bridge(4): document net.link.bridge.pfil_onlyip

[dragonfly.git] / sys / bus / cam / cam_xpt.c

/*
 * Implementation of the Common Access Method Transport (XPT) layer.
 *
 * Copyright (c) 1997, 1998, 1999 Justin T. Gibbs.
 * Copyright (c) 1997, 1998, 1999 Kenneth D. Merry.
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions, and the following disclaimer,
 *    without modification, immediately at the beginning of the file.
 * 2. The name of the author may not be used to endorse or promote products
 *    derived from this software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE FOR
 * ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 *
 * $FreeBSD: src/sys/cam/cam_xpt.c,v 1.80.2.18 2002/12/09 17:31:55 gibbs Exp $
 */
#include <sys/param.h>
#include <sys/systm.h>
#include <sys/types.h>
#include <sys/malloc.h>
#include <sys/kernel.h>
#include <sys/time.h>
#include <sys/conf.h>
#include <sys/device.h>
#include <sys/fcntl.h>
#include <sys/md5.h>
#include <sys/devicestat.h>
#include <sys/interrupt.h>
#include <sys/sbuf.h>
#include <sys/taskqueue.h>
#include <sys/bus.h>
#include <sys/thread.h>
#include <sys/lock.h>
#include <sys/spinlock.h>

#include <sys/spinlock2.h>

#include <machine/clock.h>
#include <machine/stdarg.h>

#include "cam.h"
#include "cam_ccb.h"
#include "cam_periph.h"
#include "cam_sim.h"
#include "cam_xpt.h"
#include "cam_xpt_sim.h"
#include "cam_xpt_periph.h"
#include "cam_debug.h"

#include "scsi/scsi_all.h"
#include "scsi/scsi_message.h"
#include "scsi/scsi_pass.h"
#include <sys/kthread.h>
#include "opt_cam.h"

/* Datastructures internal to the xpt layer */
MALLOC_DEFINE(M_CAMXPT, "CAM XPT", "CAM XPT buffers");

/* Object for defering XPT actions to a taskqueue */
struct xpt_task {
        struct task     task;
        void            *data1;
        uintptr_t       data2;
};

/*
 * Definition of an async handler callback block.  These are used to add
 * SIMs and peripherals to the async callback lists.
 */
struct async_node {
        SLIST_ENTRY(async_node) links;
        u_int32_t       event_enable;   /* Async Event enables */
        void            (*callback)(void *arg, u_int32_t code,
                                    struct cam_path *path, void *args);
        void            *callback_arg;
};

SLIST_HEAD(async_list, async_node);
SLIST_HEAD(periph_list, cam_periph);

/*
 * This is the maximum number of high powered commands (e.g. start unit)
 * that can be outstanding at a particular time.
 */
#ifndef CAM_MAX_HIGHPOWER
#define CAM_MAX_HIGHPOWER  4
#endif

/*
 * Structure for queueing a device in a run queue.
 * There is one run queue for allocating new ccbs,
 * and another for sending ccbs to the controller.
 */
struct cam_ed_qinfo {
        cam_pinfo pinfo;
        struct    cam_ed *device;
};

/*
 * The CAM EDT (Existing Device Table) contains the device information for
 * all devices for all busses in the system.  The table contains a
 * cam_ed structure for each device on the bus.
 */
struct cam_ed {
        TAILQ_ENTRY(cam_ed) links;
        struct  cam_ed_qinfo alloc_ccb_entry;
        struct  cam_ed_qinfo send_ccb_entry;
        struct  cam_et   *target;
        struct  cam_sim  *sim;
        lun_id_t         lun_id;
        struct  camq drvq;              /*
                                         * Queue of type drivers wanting to do
                                         * work on this device.
                                         */
        struct  cam_ccbq ccbq;          /* Queue of pending ccbs */
        struct  async_list asyncs;      /* Async callback info for this B/T/L */
        struct  periph_list periphs;    /* All attached devices */
        u_int   generation;             /* Generation number */
        struct  cam_periph *owner;      /* Peripheral driver's ownership tag */
        struct  xpt_quirk_entry *quirk; /* Oddities about this device */
                                        /* Storage for the inquiry data */
        cam_proto        protocol;
        u_int            protocol_version;
        cam_xport        transport;
        u_int            transport_version;
        struct           scsi_inquiry_data inq_data;
        u_int8_t         inq_flags;     /*
                                         * Current settings for inquiry flags.
                                         * This allows us to override settings
                                         * like disconnection and tagged
                                         * queuing for a device.
                                         */
        u_int8_t         queue_flags;   /* Queue flags from the control page */
        u_int8_t         serial_num_len;
        u_int8_t        *serial_num;
        u_int32_t        qfrozen_cnt;
        u_int32_t        flags;
#define CAM_DEV_UNCONFIGURED            0x01
#define CAM_DEV_REL_TIMEOUT_PENDING     0x02
#define CAM_DEV_REL_ON_COMPLETE         0x04
#define CAM_DEV_REL_ON_QUEUE_EMPTY      0x08
#define CAM_DEV_RESIZE_QUEUE_NEEDED     0x10
#define CAM_DEV_TAG_AFTER_COUNT         0x20
#define CAM_DEV_INQUIRY_DATA_VALID      0x40
#define CAM_DEV_IN_DV                   0x80
#define CAM_DEV_DV_HIT_BOTTOM           0x100
        u_int32_t        tag_delay_count;
#define CAM_TAG_DELAY_COUNT             5
        u_int32_t        tag_saved_openings;
        u_int32_t        refcount;
        struct callout   callout;
};

/*
 * Each target is represented by an ET (Existing Target).  These
 * entries are created when a target is successfully probed with an
 * identify, and removed when a device fails to respond after a number
 * of retries, or a bus rescan finds the device missing.
 */
struct cam_et {
        TAILQ_HEAD(, cam_ed) ed_entries;
        TAILQ_ENTRY(cam_et) links;
        struct  cam_eb  *bus;
        target_id_t     target_id;
        u_int32_t       refcount;
        u_int           generation;
        struct          timeval last_reset;     /* uptime of last reset */
};

/*
 * Each bus is represented by an EB (Existing Bus).  These entries
 * are created by calls to xpt_bus_register and deleted by calls to
 * xpt_bus_deregister.
 */
struct cam_eb {
        TAILQ_HEAD(, cam_et) et_entries;
        TAILQ_ENTRY(cam_eb)  links;
        path_id_t            path_id;
        struct cam_sim       *sim;
        struct timeval       last_reset;        /* uptime of last reset */
        u_int32_t            flags;
#define CAM_EB_RUNQ_SCHEDULED   0x01
        u_int32_t            refcount;
        u_int                generation;
        int                  counted_to_config; /* busses_to_config */
};

struct cam_path {
        struct cam_periph *periph;
        struct cam_eb     *bus;
        struct cam_et     *target;
        struct cam_ed     *device;
};

struct xpt_quirk_entry {
        struct scsi_inquiry_pattern inq_pat;
        u_int8_t quirks;
#define CAM_QUIRK_NOLUNS        0x01
#define CAM_QUIRK_NOSERIAL      0x02
#define CAM_QUIRK_HILUNS        0x04
#define CAM_QUIRK_NOHILUNS      0x08
        u_int mintags;
        u_int maxtags;
};

static int cam_srch_hi = 0;
TUNABLE_INT("kern.cam.cam_srch_hi", &cam_srch_hi);
static int sysctl_cam_search_luns(SYSCTL_HANDLER_ARGS);
SYSCTL_PROC(_kern_cam, OID_AUTO, cam_srch_hi, CTLTYPE_INT|CTLFLAG_RW, 0, 0,
    sysctl_cam_search_luns, "I",
    "allow search above LUN 7 for SCSI3 and greater devices");

#define CAM_SCSI2_MAXLUN        8
/*
 * If we're not quirked to search <= the first 8 luns
 * and we are either quirked to search above lun 8,
 * or we're > SCSI-2 and we've enabled hilun searching,
 * or we're > SCSI-2 and the last lun was a success,
 * we can look for luns above lun 8.
 */
#define CAN_SRCH_HI_SPARSE(dv)                          \
  (((dv->quirk->quirks & CAM_QUIRK_NOHILUNS) == 0)      \
  && ((dv->quirk->quirks & CAM_QUIRK_HILUNS)            \
  || (SID_ANSI_REV(&dv->inq_data) > SCSI_REV_2 && cam_srch_hi)))

#define CAN_SRCH_HI_DENSE(dv)                           \
  (((dv->quirk->quirks & CAM_QUIRK_NOHILUNS) == 0)      \
  && ((dv->quirk->quirks & CAM_QUIRK_HILUNS)            \
  || (SID_ANSI_REV(&dv->inq_data) > SCSI_REV_2)))

typedef enum {
        XPT_FLAG_OPEN           = 0x01
} xpt_flags;

struct xpt_softc {
        xpt_flags               flags;
        u_int32_t               xpt_generation;

        /* number of high powered commands that can go through right now */
        STAILQ_HEAD(highpowerlist, ccb_hdr)     highpowerq;
        int                     num_highpower;

        /* queue for handling async rescan requests. */
        TAILQ_HEAD(, ccb_hdr)   ccb_scanq;
        int                     ccb_scanq_running;

        /* Registered busses */
        TAILQ_HEAD(,cam_eb)     xpt_busses;
        u_int                   bus_generation;

        struct intr_config_hook *xpt_config_hook;

        struct lock             xpt_topo_lock;
        struct lock             xpt_lock;
};

static const char quantum[] = "QUANTUM";
static const char sony[] = "SONY";
static const char west_digital[] = "WDIGTL";
static const char samsung[] = "SAMSUNG";
static const char seagate[] = "SEAGATE";
static const char microp[] = "MICROP";

static struct xpt_quirk_entry xpt_quirk_table[] =
{
        {
                /* Reports QUEUE FULL for temporary resource shortages */
                { T_DIRECT, SIP_MEDIA_FIXED, quantum, "XP39100*", "*" },
                /*quirks*/0, /*mintags*/24, /*maxtags*/32
        },
        {
                /* Reports QUEUE FULL for temporary resource shortages */
                { T_DIRECT, SIP_MEDIA_FIXED, quantum, "XP34550*", "*" },
                /*quirks*/0, /*mintags*/24, /*maxtags*/32
        },
        {
                /* Reports QUEUE FULL for temporary resource shortages */
                { T_DIRECT, SIP_MEDIA_FIXED, quantum, "XP32275*", "*" },
                /*quirks*/0, /*mintags*/24, /*maxtags*/32
        },
        {
                /* Broken tagged queuing drive */
                { T_DIRECT, SIP_MEDIA_FIXED, microp, "4421-07*", "*" },
                /*quirks*/0, /*mintags*/0, /*maxtags*/0
        },
        {
                /* Broken tagged queuing drive */
                { T_DIRECT, SIP_MEDIA_FIXED, "HP", "C372*", "*" },
                /*quirks*/0, /*mintags*/0, /*maxtags*/0
        },
        {
                /* Broken tagged queuing drive */
                { T_DIRECT, SIP_MEDIA_FIXED, microp, "3391*", "x43h" },
                /*quirks*/0, /*mintags*/0, /*maxtags*/0
        },
        {
                /*
                 * Unfortunately, the Quantum Atlas III has the same
                 * problem as the Atlas II drives above.
                 * Reported by: "Johan Granlund" <johan@granlund.nu>
                 *
                 * For future reference, the drive with the problem was:
                 * QUANTUM QM39100TD-SW N1B0
                 *
                 * It's possible that Quantum will fix the problem in later
                 * firmware revisions.  If that happens, the quirk entry
                 * will need to be made specific to the firmware revisions
                 * with the problem.
                 *
                 */
                /* Reports QUEUE FULL for temporary resource shortages */
                { T_DIRECT, SIP_MEDIA_FIXED, quantum, "QM39100*", "*" },
                /*quirks*/0, /*mintags*/24, /*maxtags*/32
        },
        {
                /*
                 * 18 Gig Atlas III, same problem as the 9G version.
                 * Reported by: Andre Albsmeier
                 *              <andre.albsmeier@mchp.siemens.de>
                 *
                 * For future reference, the drive with the problem was:
                 * QUANTUM QM318000TD-S N491
                 */
                /* Reports QUEUE FULL for temporary resource shortages */
                { T_DIRECT, SIP_MEDIA_FIXED, quantum, "QM318000*", "*" },
                /*quirks*/0, /*mintags*/24, /*maxtags*/32
        },
        {
                /*
                 * Broken tagged queuing drive
                 * Reported by: Bret Ford <bford@uop.cs.uop.edu>
                 *         and: Martin Renters <martin@tdc.on.ca>
                 */
                { T_DIRECT, SIP_MEDIA_FIXED, seagate, "ST410800*", "71*" },
                /*quirks*/0, /*mintags*/0, /*maxtags*/0
        },
                /*
                 * The Seagate Medalist Pro drives have very poor write
                 * performance with anything more than 2 tags.
                 *
                 * Reported by:  Paul van der Zwan <paulz@trantor.xs4all.nl>
                 * Drive:  <SEAGATE ST36530N 1444>
                 *
                 * Reported by:  Jeremy Lea <reg@shale.csir.co.za>
                 * Drive:  <SEAGATE ST34520W 1281>
                 *
                 * No one has actually reported that the 9G version
                 * (ST39140*) of the Medalist Pro has the same problem, but
                 * we're assuming that it does because the 4G and 6.5G
                 * versions of the drive are broken.
                 */
        {
                { T_DIRECT, SIP_MEDIA_FIXED, seagate, "ST34520*", "*"},
                /*quirks*/0, /*mintags*/2, /*maxtags*/2
        },
        {
                { T_DIRECT, SIP_MEDIA_FIXED, seagate, "ST36530*", "*"},
                /*quirks*/0, /*mintags*/2, /*maxtags*/2
        },
        {
                { T_DIRECT, SIP_MEDIA_FIXED, seagate, "ST39140*", "*"},
                /*quirks*/0, /*mintags*/2, /*maxtags*/2
        },
        {
                /*
                 * Slow when tagged queueing is enabled.  Write performance
                 * steadily drops off with more and more concurrent
                 * transactions.  Best sequential write performance with
                 * tagged queueing turned off and write caching turned on.
                 *
                 * PR:  kern/10398
                 * Submitted by:  Hideaki Okada <hokada@isl.melco.co.jp>
                 * Drive:  DCAS-34330 w/ "S65A" firmware.
                 *
                 * The drive with the problem had the "S65A" firmware
                 * revision, and has also been reported (by Stephen J.
                 * Roznowski <sjr@home.net>) for a drive with the "S61A"
                 * firmware revision.
                 *
                 * Although no one has reported problems with the 2 gig
                 * version of the DCAS drive, the assumption is that it
                 * has the same problems as the 4 gig version.  Therefore
                 * this quirk entries disables tagged queueing for all
                 * DCAS drives.
                 */
                { T_DIRECT, SIP_MEDIA_FIXED, "IBM", "DCAS*", "*" },
                /*quirks*/0, /*mintags*/0, /*maxtags*/0
        },
        {
                /* Broken tagged queuing drive */
                { T_DIRECT, SIP_MEDIA_REMOVABLE, "iomega", "jaz*", "*" },
                /*quirks*/0, /*mintags*/0, /*maxtags*/0
        },
        {
                /* Broken tagged queuing drive */
                { T_DIRECT, SIP_MEDIA_FIXED, "CONNER", "CFP2107*", "*" },
                /*quirks*/0, /*mintags*/0, /*maxtags*/0
        },
        {
                /* This does not support other than LUN 0 */
                { T_DIRECT, SIP_MEDIA_FIXED, "VMware*", "*", "*" },
                CAM_QUIRK_NOLUNS, /*mintags*/2, /*maxtags*/255
        },
        {
                /*
                 * Broken tagged queuing drive.
                 * Submitted by:
                 * NAKAJI Hiroyuki <nakaji@zeisei.dpri.kyoto-u.ac.jp>
                 * in PR kern/9535
                 */
                { T_DIRECT, SIP_MEDIA_FIXED, samsung, "WN34324U*", "*" },
                /*quirks*/0, /*mintags*/0, /*maxtags*/0
        },
        {
                /*
                 * Slow when tagged queueing is enabled. (1.5MB/sec versus
                 * 8MB/sec.)
                 * Submitted by: Andrew Gallatin <gallatin@cs.duke.edu>
                 * Best performance with these drives is achieved with
                 * tagged queueing turned off, and write caching turned on.
                 */
                { T_DIRECT, SIP_MEDIA_FIXED, west_digital, "WDE*", "*" },
                /*quirks*/0, /*mintags*/0, /*maxtags*/0
        },
        {
                /*
                 * Slow when tagged queueing is enabled. (1.5MB/sec versus
                 * 8MB/sec.)
                 * Submitted by: Andrew Gallatin <gallatin@cs.duke.edu>
                 * Best performance with these drives is achieved with
                 * tagged queueing turned off, and write caching turned on.
                 */
                { T_DIRECT, SIP_MEDIA_FIXED, west_digital, "ENTERPRISE", "*" },
                /*quirks*/0, /*mintags*/0, /*maxtags*/0
        },
        {
                /*
                 * Doesn't handle queue full condition correctly,
                 * so we need to limit maxtags to what the device
                 * can handle instead of determining this automatically.
                 */
                { T_DIRECT, SIP_MEDIA_FIXED, samsung, "WN321010S*", "*" },
                /*quirks*/0, /*mintags*/2, /*maxtags*/32
        },
        {
                /* Really only one LUN */
                { T_ENCLOSURE, SIP_MEDIA_FIXED, "SUN", "SENA", "*" },
                CAM_QUIRK_NOLUNS, /*mintags*/0, /*maxtags*/0
        },
        {
                /* I can't believe we need a quirk for DPT volumes. */
                { T_ANY, SIP_MEDIA_FIXED|SIP_MEDIA_REMOVABLE, "DPT", "*", "*" },
                CAM_QUIRK_NOLUNS,
                /*mintags*/0, /*maxtags*/255
        },
        {
                /*
                 * Many Sony CDROM drives don't like multi-LUN probing.
                 */
                { T_CDROM, SIP_MEDIA_REMOVABLE, sony, "CD-ROM CDU*", "*" },
                CAM_QUIRK_NOLUNS, /*mintags*/0, /*maxtags*/0
        },
        {
                /*
                 * This drive doesn't like multiple LUN probing.
                 * Submitted by:  Parag Patel <parag@cgt.com>
                 */
                { T_WORM, SIP_MEDIA_REMOVABLE, sony, "CD-R   CDU9*", "*" },
                CAM_QUIRK_NOLUNS, /*mintags*/0, /*maxtags*/0
        },
        {
                { T_WORM, SIP_MEDIA_REMOVABLE, "YAMAHA", "CDR100*", "*" },
                CAM_QUIRK_NOLUNS, /*mintags*/0, /*maxtags*/0
        },
        {
                /*
                 * The 8200 doesn't like multi-lun probing, and probably
                 * don't like serial number requests either.
                 */
                {
                        T_SEQUENTIAL, SIP_MEDIA_REMOVABLE, "EXABYTE",
                        "EXB-8200*", "*"
                },
                CAM_QUIRK_NOLUNS, /*mintags*/0, /*maxtags*/0
        },
        {
                /*
                 * Let's try the same as above, but for a drive that says
                 * it's an IPL-6860 but is actually an EXB 8200.
                 */
                {
                        T_SEQUENTIAL, SIP_MEDIA_REMOVABLE, "EXABYTE",
                        "IPL-6860*", "*"
                },
                CAM_QUIRK_NOLUNS, /*mintags*/0, /*maxtags*/0
        },
        {
                /*
                 * These Hitachi drives don't like multi-lun probing.
                 * The PR submitter has a DK319H, but says that the Linux
                 * kernel has a similar work-around for the DK312 and DK314,
                 * so all DK31* drives are quirked here.
                 * PR:            misc/18793
                 * Submitted by:  Paul Haddad <paul@pth.com>
                 */
                { T_DIRECT, SIP_MEDIA_FIXED, "HITACHI", "DK31*", "*" },
                CAM_QUIRK_NOLUNS, /*mintags*/2, /*maxtags*/255
        },
        {
                /*
                 * The Hitachi CJ series with J8A8 firmware apparantly has
                 * problems with tagged commands.
                 * PR: 23536
                 * Reported by: amagai@nue.org
                 */
                { T_DIRECT, SIP_MEDIA_FIXED, "HITACHI", "DK32CJ*", "J8A8" },
                CAM_QUIRK_NOLUNS, /*mintags*/0, /*maxtags*/0
        },
        {
                /*
                 * These are the large storage arrays.
                 * Submitted by:  William Carrel <william.carrel@infospace.com>
                 */
                { T_DIRECT, SIP_MEDIA_FIXED, "HITACHI", "OPEN*", "*" },
                CAM_QUIRK_HILUNS, 2, 1024
        },
        {
                /*
                 * This old revision of the TDC3600 is also SCSI-1, and
                 * hangs upon serial number probing.
                 */
                {
                        T_SEQUENTIAL, SIP_MEDIA_REMOVABLE, "TANDBERG",
                        " TDC 3600", "U07:"
                },
                CAM_QUIRK_NOSERIAL, /*mintags*/0, /*maxtags*/0
        },
        {
                /*
                 * Would repond to all LUNs if asked for.
                 */
                {
                        T_SEQUENTIAL, SIP_MEDIA_REMOVABLE, "CALIPER",
                        "CP150", "*"
                },
                CAM_QUIRK_NOLUNS, /*mintags*/0, /*maxtags*/0
        },
        {
                /*
                 * Would repond to all LUNs if asked for.
                 */
                {
                        T_SEQUENTIAL, SIP_MEDIA_REMOVABLE, "KENNEDY",
                        "96X2*", "*"
                },
                CAM_QUIRK_NOLUNS, /*mintags*/0, /*maxtags*/0
        },
        {
                /* Submitted by: Matthew Dodd <winter@jurai.net> */
                { T_PROCESSOR, SIP_MEDIA_FIXED, "Cabletrn", "EA41*", "*" },
                CAM_QUIRK_NOLUNS, /*mintags*/0, /*maxtags*/0
        },
        {
                /* Submitted by: Matthew Dodd <winter@jurai.net> */
                { T_PROCESSOR, SIP_MEDIA_FIXED, "CABLETRN", "EA41*", "*" },
                CAM_QUIRK_NOLUNS, /*mintags*/0, /*maxtags*/0
        },
        {
                /* TeraSolutions special settings for TRC-22 RAID */
                { T_DIRECT, SIP_MEDIA_FIXED, "TERASOLU", "TRC-22", "*" },
                  /*quirks*/0, /*mintags*/55, /*maxtags*/255
        },
        {
                /* Veritas Storage Appliance */
                { T_DIRECT, SIP_MEDIA_FIXED, "VERITAS", "*", "*" },
                  CAM_QUIRK_HILUNS, /*mintags*/2, /*maxtags*/1024
        },
        {
                /*
                 * Would respond to all LUNs.  Device type and removable
                 * flag are jumper-selectable.
                 */
                { T_ANY, SIP_MEDIA_REMOVABLE|SIP_MEDIA_FIXED, "MaxOptix",
                  "Tahiti 1", "*"
                },
                CAM_QUIRK_NOLUNS, /*mintags*/0, /*maxtags*/0
        },
        {
                /* EasyRAID E5A aka. areca ARC-6010 */
                { T_DIRECT, SIP_MEDIA_FIXED, "easyRAID", "*", "*" },
                  CAM_QUIRK_NOHILUNS, /*mintags*/2, /*maxtags*/255
        },
        {
                { T_ENCLOSURE, SIP_MEDIA_FIXED, "DP", "BACKPLANE", "*" },
                CAM_QUIRK_NOLUNS, /*mintags*/0, /*maxtags*/0
        },
        {
                /* Default tagged queuing parameters for all devices */
                {
                  T_ANY, SIP_MEDIA_REMOVABLE|SIP_MEDIA_FIXED,
                  /*vendor*/"*", /*product*/"*", /*revision*/"*"
                },
                /*quirks*/0, /*mintags*/2, /*maxtags*/255
        },
};

static const int xpt_quirk_table_size = NELEM(xpt_quirk_table);

typedef enum {
        DM_RET_COPY             = 0x01,
        DM_RET_FLAG_MASK        = 0x0f,
        DM_RET_NONE             = 0x00,
        DM_RET_STOP             = 0x10,
        DM_RET_DESCEND          = 0x20,
        DM_RET_ERROR            = 0x30,
        DM_RET_ACTION_MASK      = 0xf0
} dev_match_ret;

typedef enum {
        XPT_DEPTH_BUS,
        XPT_DEPTH_TARGET,
        XPT_DEPTH_DEVICE,
        XPT_DEPTH_PERIPH
} xpt_traverse_depth;

struct xpt_traverse_config {
        xpt_traverse_depth      depth;
        void                    *tr_func;
        void                    *tr_arg;
};

typedef int     xpt_busfunc_t (struct cam_eb *bus, void *arg);
typedef int     xpt_targetfunc_t (struct cam_et *target, void *arg);
typedef int     xpt_devicefunc_t (struct cam_ed *device, void *arg);
typedef int     xpt_periphfunc_t (struct cam_periph *periph, void *arg);
typedef int     xpt_pdrvfunc_t (struct periph_driver **pdrv, void *arg);

/* Transport layer configuration information */
static struct xpt_softc xsoftc;

/* Queues for our software interrupt handler */
typedef TAILQ_HEAD(cam_isrq, ccb_hdr) cam_isrq_t;
typedef TAILQ_HEAD(cam_simq, cam_sim) cam_simq_t;
static cam_simq_t cam_simq;
static struct spinlock cam_simq_spin;

struct cam_periph *xpt_periph;

static periph_init_t xpt_periph_init;

static periph_init_t probe_periph_init;

static struct periph_driver xpt_driver =
{
        xpt_periph_init, "xpt",
        TAILQ_HEAD_INITIALIZER(xpt_driver.units)
};

static struct periph_driver probe_driver =
{
        probe_periph_init, "probe",
        TAILQ_HEAD_INITIALIZER(probe_driver.units)
};

PERIPHDRIVER_DECLARE(xpt, xpt_driver);
PERIPHDRIVER_DECLARE(probe, probe_driver);

static d_open_t xptopen;
static d_close_t xptclose;
static d_ioctl_t xptioctl;

static struct dev_ops xpt_ops = {
        { "xpt", 0, D_MPSAFE },
        .d_open = xptopen,
        .d_close = xptclose,
        .d_ioctl = xptioctl
};

static void dead_sim_action(struct cam_sim *sim, union ccb *ccb);
static void dead_sim_poll(struct cam_sim *sim);

/* Dummy SIM that is used when the real one has gone. */
static struct cam_sim cam_dead_sim;
static struct lock    cam_dead_lock;

/* Storage for debugging datastructures */
#ifdef  CAMDEBUG
struct cam_path *cam_dpath;
u_int32_t cam_dflags;
u_int32_t cam_debug_delay;
#endif

#if defined(CAM_DEBUG_FLAGS) && !defined(CAMDEBUG)
#error "You must have options CAMDEBUG to use options CAM_DEBUG_FLAGS"
#endif

/*
 * In order to enable the CAM_DEBUG_* options, the user must have CAMDEBUG
 * enabled.  Also, the user must have either none, or all of CAM_DEBUG_BUS,
 * CAM_DEBUG_TARGET, and CAM_DEBUG_LUN specified.
 */
#if defined(CAM_DEBUG_BUS) || defined(CAM_DEBUG_TARGET) \
    || defined(CAM_DEBUG_LUN)
#ifdef CAMDEBUG
#if !defined(CAM_DEBUG_BUS) || !defined(CAM_DEBUG_TARGET) \
    || !defined(CAM_DEBUG_LUN)
#error "You must define all or none of CAM_DEBUG_BUS, CAM_DEBUG_TARGET \
        and CAM_DEBUG_LUN"
#endif /* !CAM_DEBUG_BUS || !CAM_DEBUG_TARGET || !CAM_DEBUG_LUN */
#else /* !CAMDEBUG */
#error "You must use options CAMDEBUG if you use the CAM_DEBUG_* options"
#endif /* CAMDEBUG */
#endif /* CAM_DEBUG_BUS || CAM_DEBUG_TARGET || CAM_DEBUG_LUN */

/* Our boot-time initialization hook */
static int cam_module_event_handler(module_t, int /*modeventtype_t*/, void *);

static moduledata_t cam_moduledata = {
        "cam",
        cam_module_event_handler,
        NULL
};

static int      xpt_init(void *);

DECLARE_MODULE(cam, cam_moduledata, SI_SUB_CONFIGURE, SI_ORDER_SECOND);
MODULE_VERSION(cam, 1);


static cam_status       xpt_compile_path(struct cam_path *new_path,
                                         struct cam_periph *perph,
                                         path_id_t path_id,
                                         target_id_t target_id,
                                         lun_id_t lun_id);

static void             xpt_release_path(struct cam_path *path);

static void             xpt_async_bcast(struct async_list *async_head,
                                        u_int32_t async_code,
                                        struct cam_path *path,
                                        void *async_arg);
static void             xpt_dev_async(u_int32_t async_code,
                                      struct cam_eb *bus,
                                      struct cam_et *target,
                                      struct cam_ed *device,
                                      void *async_arg);
static path_id_t xptnextfreepathid(void);
static path_id_t xptpathid(const char *sim_name, int sim_unit, int sim_bus);
static union ccb *xpt_get_ccb(struct cam_ed *device);
static int       xpt_schedule_dev(struct camq *queue, cam_pinfo *dev_pinfo,
                                  u_int32_t new_priority);
static void      xpt_run_dev_allocq(struct cam_eb *bus);
static void      xpt_run_dev_sendq(struct cam_eb *bus);
static timeout_t xpt_release_devq_timeout;
static void      xpt_release_bus(struct cam_eb *bus);
static void      xpt_release_devq_device(struct cam_ed *dev, u_int count,
                                         int run_queue);
static struct cam_et*
                 xpt_alloc_target(struct cam_eb *bus, target_id_t target_id);
static void      xpt_release_target(struct cam_eb *bus, struct cam_et *target);
static struct cam_ed*
                 xpt_alloc_device(struct cam_eb *bus, struct cam_et *target,
                                  lun_id_t lun_id);
static void      xpt_release_device(struct cam_eb *bus, struct cam_et *target,
                                    struct cam_ed *device);
static u_int32_t xpt_dev_ccbq_resize(struct cam_path *path, int newopenings);
static struct cam_eb*
                 xpt_find_bus(path_id_t path_id);
static struct cam_et*
                 xpt_find_target(struct cam_eb *bus, target_id_t target_id);
static struct cam_ed*
                 xpt_find_device(struct cam_et *target, lun_id_t lun_id);
static void      xpt_scan_bus(struct cam_periph *periph, union ccb *ccb);
static void      xpt_scan_lun(struct cam_periph *periph,
                              struct cam_path *path, cam_flags flags,
                              union ccb *ccb);
static void      xptscandone(struct cam_periph *periph, union ccb *done_ccb);
static xpt_busfunc_t    xptconfigbuscountfunc;
static xpt_busfunc_t    xptconfigfunc;
static void      xpt_config(void *arg);
static xpt_devicefunc_t xptpassannouncefunc;
static void      xpt_finishconfig(struct cam_periph *periph, union ccb *ccb);
static void      xpt_uncount_bus (struct cam_eb *bus);
static void      xptaction(struct cam_sim *sim, union ccb *work_ccb);
static void      xptpoll(struct cam_sim *sim);
static inthand2_t swi_cambio;
static void      camisr(void *);
static void      camisr_runqueue(struct cam_sim *);
static dev_match_ret    xptbusmatch(struct dev_match_pattern *patterns,
                                    u_int num_patterns, struct cam_eb *bus);
static dev_match_ret    xptdevicematch(struct dev_match_pattern *patterns,
                                       u_int num_patterns,
                                       struct cam_ed *device);
static dev_match_ret    xptperiphmatch(struct dev_match_pattern *patterns,
                                       u_int num_patterns,
                                       struct cam_periph *periph);
static xpt_busfunc_t    xptedtbusfunc;
static xpt_targetfunc_t xptedttargetfunc;
static xpt_devicefunc_t xptedtdevicefunc;
static xpt_periphfunc_t xptedtperiphfunc;
static xpt_pdrvfunc_t   xptplistpdrvfunc;
static xpt_periphfunc_t xptplistperiphfunc;
static int              xptedtmatch(struct ccb_dev_match *cdm);
static int              xptperiphlistmatch(struct ccb_dev_match *cdm);
static int              xptbustraverse(struct cam_eb *start_bus,
                                       xpt_busfunc_t *tr_func, void *arg);
static int              xpttargettraverse(struct cam_eb *bus,
                                          struct cam_et *start_target,
                                          xpt_targetfunc_t *tr_func, void *arg);
static int              xptdevicetraverse(struct cam_et *target,
                                          struct cam_ed *start_device,
                                          xpt_devicefunc_t *tr_func, void *arg);
static int              xptperiphtraverse(struct cam_ed *device,
                                          struct cam_periph *start_periph,
                                          xpt_periphfunc_t *tr_func, void *arg);
static int              xptpdrvtraverse(struct periph_driver **start_pdrv,
                                        xpt_pdrvfunc_t *tr_func, void *arg);
static int              xptpdperiphtraverse(struct periph_driver **pdrv,
                                            struct cam_periph *start_periph,
                                            xpt_periphfunc_t *tr_func,
                                            void *arg);
static xpt_busfunc_t    xptdefbusfunc;
static xpt_targetfunc_t xptdeftargetfunc;
static xpt_devicefunc_t xptdefdevicefunc;
static xpt_periphfunc_t xptdefperiphfunc;
static int              xpt_for_all_busses(xpt_busfunc_t *tr_func, void *arg);
static int              xpt_for_all_devices(xpt_devicefunc_t *tr_func,
                                            void *arg);
static xpt_devicefunc_t xptsetasyncfunc;
static xpt_busfunc_t    xptsetasyncbusfunc;
static cam_status       xptregister(struct cam_periph *periph,
                                    void *arg);
static cam_status       proberegister(struct cam_periph *periph,
                                      void *arg);
static void      probeschedule(struct cam_periph *probe_periph);
static void      probestart(struct cam_periph *periph, union ccb *start_ccb);
static void      proberequestdefaultnegotiation(struct cam_periph *periph);
static int       proberequestbackoff(struct cam_periph *periph,
                                     struct cam_ed *device);
static void      probedone(struct cam_periph *periph, union ccb *done_ccb);
static void      probecleanup(struct cam_periph *periph);
static void      xpt_find_quirk(struct cam_ed *device);
static void      xpt_devise_transport(struct cam_path *path);
static void      xpt_set_transfer_settings(struct ccb_trans_settings *cts,
                                           struct cam_ed *device,
                                           int async_update);
static void      xpt_toggle_tags(struct cam_path *path);
static void      xpt_start_tags(struct cam_path *path);
static __inline int xpt_schedule_dev_allocq(struct cam_eb *bus,
                                            struct cam_ed *dev);
static __inline int xpt_schedule_dev_sendq(struct cam_eb *bus,
                                           struct cam_ed *dev);
static __inline int periph_is_queued(struct cam_periph *periph);
static __inline int device_is_alloc_queued(struct cam_ed *device);
static __inline int device_is_send_queued(struct cam_ed *device);
static __inline int dev_allocq_is_runnable(struct cam_devq *devq);

static __inline int
xpt_schedule_dev_allocq(struct cam_eb *bus, struct cam_ed *dev)
{
        int retval;

        if (bus->sim->devq && dev->ccbq.devq_openings > 0) {
                if ((dev->flags & CAM_DEV_RESIZE_QUEUE_NEEDED) != 0) {
                        cam_ccbq_resize(&dev->ccbq,
                                        dev->ccbq.dev_openings
                                        + dev->ccbq.dev_active);
                        dev->flags &= ~CAM_DEV_RESIZE_QUEUE_NEEDED;
                }
                /*
                 * The priority of a device waiting for CCB resources
                 * is that of the the highest priority peripheral driver
                 * enqueued.
                 */
                retval = xpt_schedule_dev(&bus->sim->devq->alloc_queue,
                                          &dev->alloc_ccb_entry.pinfo,
                                          CAMQ_GET_HEAD(&dev->drvq)->priority);
        } else {
                retval = 0;
        }

        return (retval);
}

static __inline int
xpt_schedule_dev_sendq(struct cam_eb *bus, struct cam_ed *dev)
{
        int     retval;

        if (bus->sim->devq && dev->ccbq.dev_openings > 0) {
                /*
                 * The priority of a device waiting for controller
                 * resources is that of the the highest priority CCB
                 * enqueued.
                 */
                retval =
                    xpt_schedule_dev(&bus->sim->devq->send_queue,
                                     &dev->send_ccb_entry.pinfo,
                                     CAMQ_GET_HEAD(&dev->ccbq.queue)->priority);
        } else {
                retval = 0;
        }
        return (retval);
}

static __inline int
periph_is_queued(struct cam_periph *periph)
{
        return (periph->pinfo.index != CAM_UNQUEUED_INDEX);
}

static __inline int
device_is_alloc_queued(struct cam_ed *device)
{
        return (device->alloc_ccb_entry.pinfo.index != CAM_UNQUEUED_INDEX);
}

static __inline int
device_is_send_queued(struct cam_ed *device)
{
        return (device->send_ccb_entry.pinfo.index != CAM_UNQUEUED_INDEX);
}

static __inline int
dev_allocq_is_runnable(struct cam_devq *devq)
{
        /*
         * Have work to do.
         * Have space to do more work.
         * Allowed to do work.
         */
        return ((devq->alloc_queue.qfrozen_cnt == 0)
             && (devq->alloc_queue.entries > 0)
             && (devq->alloc_openings > 0));
}

static void
xpt_periph_init(void)
{
        make_dev(&xpt_ops, 0, UID_ROOT, GID_OPERATOR, 0600, "xpt0");
}

static void
probe_periph_init(void)
{
}


static void
xptdone(struct cam_periph *periph, union ccb *done_ccb)
{
        /* Caller will release the CCB */
        wakeup(&done_ccb->ccb_h.cbfcnp);
}

static int
xptopen(struct dev_open_args *ap)
{
        cdev_t dev = ap->a_head.a_dev;

        /*
         * Only allow read-write access.
         */
        if (((ap->a_oflags & FWRITE) == 0) || ((ap->a_oflags & FREAD) == 0))
                return(EPERM);

        /*
         * We don't allow nonblocking access.
         */
        if ((ap->a_oflags & O_NONBLOCK) != 0) {
                kprintf("%s: can't do nonblocking access\n", devtoname(dev));
                return(ENODEV);
        }

        /* Mark ourselves open */
        lockmgr(&xsoftc.xpt_lock, LK_EXCLUSIVE);
        xsoftc.flags |= XPT_FLAG_OPEN;
        lockmgr(&xsoftc.xpt_lock, LK_RELEASE);

        return(0);
}

static int
xptclose(struct dev_close_args *ap)
{

        /* Mark ourselves closed */
        lockmgr(&xsoftc.xpt_lock, LK_EXCLUSIVE);
        xsoftc.flags &= ~XPT_FLAG_OPEN;
        lockmgr(&xsoftc.xpt_lock, LK_RELEASE);

        return(0);
}

/*
 * Don't automatically grab the xpt softc lock here even though this is going
 * through the xpt device.  The xpt device is really just a back door for
 * accessing other devices and SIMs, so the right thing to do is to grab
 * the appropriate SIM lock once the bus/SIM is located.
 */
static int
xptioctl(struct dev_ioctl_args *ap)
{
        int error;

        error = 0;

        switch(ap->a_cmd) {
        /*
         * For the transport layer CAMIOCOMMAND ioctl, we really only want
         * to accept CCB types that don't quite make sense to send through a
         * passthrough driver.
         */
        case CAMIOCOMMAND: {
                union ccb *ccb;
                union ccb *inccb;
                struct cam_eb *bus;

                inccb = (union ccb *)ap->a_data;

                bus = xpt_find_bus(inccb->ccb_h.path_id);
                if (bus == NULL) {
                        error = EINVAL;
                        break;
                }

                switch(inccb->ccb_h.func_code) {
                case XPT_SCAN_BUS:
                case XPT_RESET_BUS:
                        if ((inccb->ccb_h.target_id != CAM_TARGET_WILDCARD)
                         || (inccb->ccb_h.target_lun != CAM_LUN_WILDCARD)) {
                                error = EINVAL;
                                break;
                        }
                        /* FALLTHROUGH */
                case XPT_PATH_INQ:
                case XPT_ENG_INQ:
                case XPT_SCAN_LUN:

                        ccb = xpt_alloc_ccb();

                        CAM_SIM_LOCK(bus->sim);

                        /*
                         * Create a path using the bus, target, and lun the
                         * user passed in.
                         */
                        if (xpt_create_path(&ccb->ccb_h.path, xpt_periph,
                                            inccb->ccb_h.path_id,
                                            inccb->ccb_h.target_id,
                                            inccb->ccb_h.target_lun) !=
                                            CAM_REQ_CMP){
                                error = EINVAL;
                                CAM_SIM_UNLOCK(bus->sim);
                                xpt_free_ccb(&ccb->ccb_h);
                                break;
                        }
                        /* Ensure all of our fields are correct */
                        xpt_setup_ccb(&ccb->ccb_h, ccb->ccb_h.path,
                                      inccb->ccb_h.pinfo.priority);
                        xpt_merge_ccb(ccb, inccb);
                        ccb->ccb_h.cbfcnp = xptdone;
                        cam_periph_runccb(ccb, NULL, 0, 0, NULL);
                        bcopy(ccb, inccb, sizeof(union ccb));
                        xpt_free_path(ccb->ccb_h.path);
                        xpt_free_ccb(&ccb->ccb_h);
                        CAM_SIM_UNLOCK(bus->sim);
                        break;

                case XPT_DEBUG: {
                        union ccb *ccb;

                        ccb = xpt_alloc_ccb();

                        /*
                         * This is an immediate CCB, so it's okay to
                         * allocate it on the stack.
                         */

                        CAM_SIM_LOCK(bus->sim);

                        /*
                         * Create a path using the bus, target, and lun the
                         * user passed in.
                         */
                        if (xpt_create_path(&ccb->ccb_h.path, xpt_periph,
                                            inccb->ccb_h.path_id,
                                            inccb->ccb_h.target_id,
                                            inccb->ccb_h.target_lun) !=
                                            CAM_REQ_CMP){
                                error = EINVAL;
                                CAM_SIM_UNLOCK(bus->sim);
                                xpt_free_ccb(&ccb->ccb_h);
                                break;
                        }
                        /* Ensure all of our fields are correct */
                        xpt_setup_ccb(&ccb->ccb_h, ccb->ccb_h.path,
                                      inccb->ccb_h.pinfo.priority);
                        xpt_merge_ccb(ccb, inccb);
                        ccb->ccb_h.cbfcnp = xptdone;
                        xpt_action(ccb);
                        CAM_SIM_UNLOCK(bus->sim);
                        bcopy(ccb, inccb, sizeof(union ccb));
                        inccb->ccb_h.timeout_ch = NULL; /* SAFETY */
                        xpt_free_path(ccb->ccb_h.path);
                        xpt_free_ccb(&ccb->ccb_h);

                        break;

                }
                case XPT_DEV_MATCH: {
                        struct cam_periph_map_info mapinfo;
                        struct cam_path *old_path;

                        /*
                         * We can't deal with physical addresses for this
                         * type of transaction.
                         */
                        if (inccb->ccb_h.flags & CAM_DATA_PHYS) {
                                error = EINVAL;
                                break;
                        }

                        /*
                         * Save this in case the caller had it set to
                         * something in particular.
                         */
                        old_path = inccb->ccb_h.path;

                        /*
                         * We really don't need a path for the matching
                         * code.  The path is needed because of the
                         * debugging statements in xpt_action().  They
                         * assume that the CCB has a valid path.
                         */
                        inccb->ccb_h.path = xpt_periph->path;

                        bzero(&mapinfo, sizeof(mapinfo));

                        /*
                         * Map the pattern and match buffers into kernel
                         * virtual address space.
                         */
                        error = cam_periph_mapmem(inccb, &mapinfo);

                        if (error) {
                                inccb->ccb_h.path = old_path;
                                break;
                        }

                        /*
                         * This is an immediate CCB, we can send it on directly.
                         */
                        xpt_action(inccb);

                        /*
                         * Map the buffers back into user space.
                         */
                        cam_periph_unmapmem(inccb, &mapinfo);

                        inccb->ccb_h.path = old_path;

                        error = 0;
                        break;
                }
                default:
                        error = ENOTSUP;
                        break;
                }
                xpt_release_bus(bus);
                break;
        }
        /*
         * This is the getpassthru ioctl. It takes a XPT_GDEVLIST ccb as input,
         * with the periphal driver name and unit name filled in.  The other
         * fields don't really matter as input.  The passthrough driver name
         * ("pass"), and unit number are passed back in the ccb.  The current
         * device generation number, and the index into the device peripheral
         * driver list, and the status are also passed back.  Note that
         * since we do everything in one pass, unlike the XPT_GDEVLIST ccb,
         * we never return a status of CAM_GDEVLIST_LIST_CHANGED.  It is
         * (or rather should be) impossible for the device peripheral driver
         * list to change since we look at the whole thing in one pass, and
         * we do it with lock protection.
         *
         */
        case CAMGETPASSTHRU: {
                union ccb *ccb;
                struct cam_periph *periph;
                struct periph_driver **p_drv;
                char   *name;
                u_int unit;
                u_int cur_generation;
                int base_periph_found;
                int splbreaknum;

                ccb = (union ccb *)ap->a_data;
                unit = ccb->cgdl.unit_number;
                name = ccb->cgdl.periph_name;
                /*
                 * Every 100 devices, we want to drop our lock protection to
                 * give the software interrupt handler a chance to run.
                 * Most systems won't run into this check, but this should
                 * avoid starvation in the software interrupt handler in
                 * large systems.
                 */
                splbreaknum = 100;

                ccb = (union ccb *)ap->a_data;

                base_periph_found = 0;

                /*
                 * Sanity check -- make sure we don't get a null peripheral
                 * driver name.
                 */
                if (*ccb->cgdl.periph_name == '\0') {
                        error = EINVAL;
                        break;
                }

                /* Keep the list from changing while we traverse it */
                lockmgr(&xsoftc.xpt_topo_lock, LK_EXCLUSIVE);
ptstartover:
                cur_generation = xsoftc.xpt_generation;

                /* first find our driver in the list of drivers */
                for (p_drv = periph_drivers; *p_drv != NULL; p_drv++) {
                        if (strcmp((*p_drv)->driver_name, name) == 0)
                                break;
                }

                if (*p_drv == NULL) {
                        lockmgr(&xsoftc.xpt_topo_lock, LK_RELEASE);
                        ccb->ccb_h.status = CAM_REQ_CMP_ERR;
                        ccb->cgdl.status = CAM_GDEVLIST_ERROR;
                        *ccb->cgdl.periph_name = '\0';
                        ccb->cgdl.unit_number = 0;
                        error = ENOENT;
                        break;
                }

                /*
                 * Run through every peripheral instance of this driver
                 * and check to see whether it matches the unit passed
                 * in by the user.  If it does, get out of the loops and
                 * find the passthrough driver associated with that
                 * peripheral driver.
                 */
                TAILQ_FOREACH(periph, &(*p_drv)->units, unit_links) {

                        if (periph->unit_number == unit) {
                                break;
                        } else if (--splbreaknum == 0) {
                                lockmgr(&xsoftc.xpt_topo_lock, LK_RELEASE);
                                lockmgr(&xsoftc.xpt_topo_lock, LK_EXCLUSIVE);
                                splbreaknum = 100;
                                if (cur_generation != xsoftc.xpt_generation)
                                       goto ptstartover;
                        }
                }
                /*
                 * If we found the peripheral driver that the user passed
                 * in, go through all of the peripheral drivers for that
                 * particular device and look for a passthrough driver.
                 */
                if (periph != NULL) {
                        struct cam_ed *device;
                        int i;

                        base_periph_found = 1;
                        device = periph->path->device;
                        for (i = 0, periph = SLIST_FIRST(&device->periphs);
                             periph != NULL;
                             periph = SLIST_NEXT(periph, periph_links), i++) {
                                /*
                                 * Check to see whether we have a
                                 * passthrough device or not.
                                 */
                                if (strcmp(periph->periph_name, "pass") == 0) {
                                        /*
                                         * Fill in the getdevlist fields.
                                         */
                                        strcpy(ccb->cgdl.periph_name,
                                               periph->periph_name);
                                        ccb->cgdl.unit_number =
                                                periph->unit_number;
                                        if (SLIST_NEXT(periph, periph_links))
                                                ccb->cgdl.status =
                                                        CAM_GDEVLIST_MORE_DEVS;
                                        else
                                                ccb->cgdl.status =
                                                       CAM_GDEVLIST_LAST_DEVICE;
                                        ccb->cgdl.generation =
                                                device->generation;
                                        ccb->cgdl.index = i;
                                        /*
                                         * Fill in some CCB header fields
                                         * that the user may want.
                                         */
                                        ccb->ccb_h.path_id =
                                                periph->path->bus->path_id;
                                        ccb->ccb_h.target_id =
                                                periph->path->target->target_id;
                                        ccb->ccb_h.target_lun =
                                                periph->path->device->lun_id;
                                        ccb->ccb_h.status = CAM_REQ_CMP;
                                        break;
                                }
                        }
                }

                /*
                 * If the periph is null here, one of two things has
                 * happened.  The first possibility is that we couldn't
                 * find the unit number of the particular peripheral driver
                 * that the user is asking about.  e.g. the user asks for
                 * the passthrough driver for "da11".  We find the list of
                 * "da" peripherals all right, but there is no unit 11.
                 * The other possibility is that we went through the list
                 * of peripheral drivers attached to the device structure,
                 * but didn't find one with the name "pass".  Either way,
                 * we return ENOENT, since we couldn't find something.
                 */
                if (periph == NULL) {
                        ccb->ccb_h.status = CAM_REQ_CMP_ERR;
                        ccb->cgdl.status = CAM_GDEVLIST_ERROR;
                        *ccb->cgdl.periph_name = '\0';
                        ccb->cgdl.unit_number = 0;
                        error = ENOENT;
                        /*
                         * It is unfortunate that this is even necessary,
                         * but there are many, many clueless users out there.
                         * If this is true, the user is looking for the
                         * passthrough driver, but doesn't have one in his
                         * kernel.
                         */
                        if (base_periph_found == 1) {
                                kprintf("xptioctl: pass driver is not in the "
                                       "kernel\n");
                                kprintf("xptioctl: put \"device pass\" in "
                                       "your kernel config file\n");
                        }
                }
                lockmgr(&xsoftc.xpt_topo_lock, LK_RELEASE);
                break;
                }
        default:
                error = ENOTTY;
                break;
        }

        return(error);
}

static int
cam_module_event_handler(module_t mod, int what, void *arg)
{
        int error;

        switch (what) {
        case MOD_LOAD:
                if ((error = xpt_init(NULL)) != 0)
                        return (error);
                break;
        case MOD_UNLOAD:
                return EBUSY;
        default:
                return EOPNOTSUPP;
        }

        return 0;
}

/*
 * Thread to handle asynchronous main-context requests.
 *
 * This function is typically used by drivers to perform complex actions
 * such as bus scans and engineering requests in a main context instead
 * of an interrupt context.
 */
static void
xpt_scanner_thread(void *dummy)
{
        union ccb       *ccb;
        struct cam_sim  *sim;

        for (;;) {
                xpt_lock_buses();
                xsoftc.ccb_scanq_running = 1;
                while ((ccb = (void *)TAILQ_FIRST(&xsoftc.ccb_scanq)) != NULL) {
                        TAILQ_REMOVE(&xsoftc.ccb_scanq, &ccb->ccb_h,
                                     sim_links.tqe);
                        xpt_unlock_buses();

                        sim = ccb->ccb_h.path->bus->sim;
                        CAM_SIM_LOCK(sim);
                        xpt_action(ccb);
                        CAM_SIM_UNLOCK(sim);

                        xpt_lock_buses();
                }
                xsoftc.ccb_scanq_running = 0;
                tsleep_interlock(&xsoftc.ccb_scanq, 0);
                xpt_unlock_buses();
                tsleep(&xsoftc.ccb_scanq, PINTERLOCKED, "ccb_scanq", 0);
        }
}

/*
 * Issue an asynchronous asction
 */
void
xpt_action_async(union ccb *ccb)
{
        xpt_lock_buses();
        TAILQ_INSERT_TAIL(&xsoftc.ccb_scanq, &ccb->ccb_h, sim_links.tqe);
        if (xsoftc.ccb_scanq_running == 0) {
                xsoftc.ccb_scanq_running = 1;
                wakeup(&xsoftc.ccb_scanq);
        }
        xpt_unlock_buses();
}


/* Functions accessed by the peripheral drivers */
static int
xpt_init(void *dummy)
{
        struct cam_sim *xpt_sim;
        struct cam_path *path;
        struct cam_devq *devq;
        cam_status status;

        TAILQ_INIT(&xsoftc.xpt_busses);
        TAILQ_INIT(&cam_simq);
        TAILQ_INIT(&xsoftc.ccb_scanq);
        STAILQ_INIT(&xsoftc.highpowerq);
        xsoftc.num_highpower = CAM_MAX_HIGHPOWER;

        spin_init(&cam_simq_spin, "cam_simq_spin");
        lockinit(&xsoftc.xpt_lock, "XPT lock", 0, LK_CANRECURSE);
        lockinit(&xsoftc.xpt_topo_lock, "XPT topology lock", 0, LK_CANRECURSE);

        SLIST_INIT(&cam_dead_sim.ccb_freeq);
        TAILQ_INIT(&cam_dead_sim.sim_doneq);
        spin_init(&cam_dead_sim.sim_spin, "cam_dead_sim");
        cam_dead_sim.sim_action = dead_sim_action;
        cam_dead_sim.sim_poll = dead_sim_poll;
        cam_dead_sim.sim_name = "dead_sim";
        cam_dead_sim.lock = &cam_dead_lock;
        lockinit(&cam_dead_lock, "XPT dead_sim lock", 0, LK_CANRECURSE);
        cam_dead_sim.flags |= CAM_SIM_DEREGISTERED;

        /*
         * The xpt layer is, itself, the equivelent of a SIM.
         * Allow 16 ccbs in the ccb pool for it.  This should
         * give decent parallelism when we probe busses and
         * perform other XPT functions.
         */
        devq = cam_simq_alloc(16);
        xpt_sim = cam_sim_alloc(xptaction,
                                xptpoll,
                                "xpt",
                                /*softc*/NULL,
                                /*unit*/0,
                                /*lock*/&xsoftc.xpt_lock,
                                /*max_dev_transactions*/0,
                                /*max_tagged_dev_transactions*/0,
                                devq);
        cam_simq_release(devq);
        if (xpt_sim == NULL)
                return (ENOMEM);

        xpt_sim->max_ccbs = 16;

        lockmgr(&xsoftc.xpt_lock, LK_EXCLUSIVE);
        if ((status = xpt_bus_register(xpt_sim, /*bus #*/0)) != CAM_SUCCESS) {
                lockmgr(&xsoftc.xpt_lock, LK_RELEASE);
                kprintf("xpt_init: xpt_bus_register failed with status %#x,"
                       " failing attach\n", status);
                return (EINVAL);
        }

        /*
         * Looking at the XPT from the SIM layer, the XPT is
         * the equivelent of a peripheral driver.  Allocate
         * a peripheral driver entry for us.
         */
        if ((status = xpt_create_path(&path, NULL, CAM_XPT_PATH_ID,
                                      CAM_TARGET_WILDCARD,
                                      CAM_LUN_WILDCARD)) != CAM_REQ_CMP) {
                lockmgr(&xsoftc.xpt_lock, LK_RELEASE);
                kprintf("xpt_init: xpt_create_path failed with status %#x,"
                       " failing attach\n", status);
                return (EINVAL);
        }

        cam_periph_alloc(xptregister, NULL, NULL, NULL, "xpt", CAM_PERIPH_BIO,
                         path, NULL, 0, xpt_sim);
        xpt_free_path(path);

        lockmgr(&xsoftc.xpt_lock, LK_RELEASE);

        /*
         * Register a callback for when interrupts are enabled.
         */
        xsoftc.xpt_config_hook = kmalloc(sizeof(struct intr_config_hook),
                                  M_CAMXPT, M_INTWAIT | M_ZERO);
        xsoftc.xpt_config_hook->ich_func = xpt_config;
        xsoftc.xpt_config_hook->ich_desc = "xpt";
        xsoftc.xpt_config_hook->ich_order = 1000;
        if (config_intrhook_establish(xsoftc.xpt_config_hook) != 0) {
                kfree (xsoftc.xpt_config_hook, M_CAMXPT);
                kprintf("xpt_init: config_intrhook_establish failed "
                       "- failing attach\n");
        }

        /* fire up rescan thread */
        if (kthread_create(xpt_scanner_thread, NULL, NULL, "xpt_thrd")) {
                kprintf("xpt_init: failed to create rescan thread\n");
        }
        /* Install our software interrupt handlers */
        register_swi_mp(SWI_CAMBIO, swi_cambio, NULL, "swi_cambio", NULL, -1);

        return (0);
}

static cam_status
xptregister(struct cam_periph *periph, void *arg)
{
        struct cam_sim *xpt_sim;

        if (periph == NULL) {
                kprintf("xptregister: periph was NULL!!\n");
                return(CAM_REQ_CMP_ERR);
        }

        xpt_sim = (struct cam_sim *)arg;
        xpt_sim->softc = periph;
        xpt_periph = periph;
        periph->softc = NULL;

        return(CAM_REQ_CMP);
}

int32_t
xpt_add_periph(struct cam_periph *periph)
{
        struct cam_ed *device;
        int32_t  status;
        struct periph_list *periph_head;

        sim_lock_assert_owned(periph->sim->lock);

        device = periph->path->device;

        periph_head = &device->periphs;

        status = CAM_REQ_CMP;

        if (device != NULL) {
                /*
                 * Make room for this peripheral
                 * so it will fit in the queue
                 * when it's scheduled to run
                 */
                status = camq_resize(&device->drvq,
                                     device->drvq.array_size + 1);

                device->generation++;

                SLIST_INSERT_HEAD(periph_head, periph, periph_links);
        }

        lockmgr(&xsoftc.xpt_topo_lock, LK_EXCLUSIVE);
        xsoftc.xpt_generation++;
        lockmgr(&xsoftc.xpt_topo_lock, LK_RELEASE);

        return (status);
}

void
xpt_remove_periph(struct cam_periph *periph)
{
        struct cam_ed *device;

        sim_lock_assert_owned(periph->sim->lock);

        device = periph->path->device;

        if (device != NULL) {
                struct periph_list *periph_head;

                periph_head = &device->periphs;

                /* Release the slot for this peripheral */
                camq_resize(&device->drvq, device->drvq.array_size - 1);

                device->generation++;

                SLIST_REMOVE(periph_head, periph, cam_periph, periph_links);
        }

        lockmgr(&xsoftc.xpt_topo_lock, LK_EXCLUSIVE);
        xsoftc.xpt_generation++;
        lockmgr(&xsoftc.xpt_topo_lock, LK_RELEASE);
}

void
xpt_announce_periph(struct cam_periph *periph, char *announce_string)
{
        struct  ccb_pathinq *cpi;
        struct  ccb_trans_settings *cts;
        struct  cam_path *path;
        u_int   speed;
        u_int   freq;
        u_int   mb;

        sim_lock_assert_owned(periph->sim->lock);

        path = periph->path;

        /* Report basic attachment and inquiry data */
        kprintf("%s%d at %s%d bus %d target %d lun %d\n",
               periph->periph_name, periph->unit_number,
               path->bus->sim->sim_name,
               path->bus->sim->unit_number,
               path->bus->sim->bus_id,
               path->target->target_id,
               path->device->lun_id);
        kprintf("%s%d: ", periph->periph_name, periph->unit_number);
        scsi_print_inquiry(&path->device->inq_data);

        /* Report serial number */
        if (path->device->serial_num_len > 0) {
                /* Don't wrap the screen  - print only the first 60 chars */
                kprintf("%s%d: Serial Number %.60s\n", periph->periph_name,
                       periph->unit_number, path->device->serial_num);
        }

        /* Acquire and report transfer speed */
        cts = &xpt_alloc_ccb()->cts;
        xpt_setup_ccb(&cts->ccb_h, path, /*priority*/1);
        cts->ccb_h.func_code = XPT_GET_TRAN_SETTINGS;
        cts->type = CTS_TYPE_CURRENT_SETTINGS;
        xpt_action((union ccb*)cts);
        if ((cts->ccb_h.status & CAM_STATUS_MASK) != CAM_REQ_CMP) {
                xpt_free_ccb(&cts->ccb_h);
                return;
        }

        /* Ask the SIM for its base transfer speed */
        cpi = &xpt_alloc_ccb()->cpi;
        xpt_setup_ccb(&cpi->ccb_h, path, /*priority*/1);
        cpi->ccb_h.func_code = XPT_PATH_INQ;
        xpt_action((union ccb *)cpi);

        speed = cpi->base_transfer_speed;
        freq = 0;
        if (cts->ccb_h.status == CAM_REQ_CMP && cts->transport == XPORT_SPI) {
                struct  ccb_trans_settings_spi *spi;

                spi = &cts->xport_specific.spi;
                if ((spi->valid & CTS_SPI_VALID_SYNC_OFFSET) != 0
                  && spi->sync_offset != 0) {
                        freq = scsi_calc_syncsrate(spi->sync_period);
                        speed = freq;
                }

                if ((spi->valid & CTS_SPI_VALID_BUS_WIDTH) != 0)
                        speed *= (0x01 << spi->bus_width);
        }
        if (cts->ccb_h.status == CAM_REQ_CMP && cts->transport == XPORT_FC) {
                struct  ccb_trans_settings_fc *fc = &cts->xport_specific.fc;
                if (fc->valid & CTS_FC_VALID_SPEED) {
                        speed = fc->bitrate;
                }
        }

        if (cts->ccb_h.status == CAM_REQ_CMP && cts->transport == XPORT_SAS) {
                struct  ccb_trans_settings_sas *sas = &cts->xport_specific.sas;
                if (sas->valid & CTS_SAS_VALID_SPEED) {
                        speed = sas->bitrate;
                }
        }

        mb = speed / 1000;
        if (mb > 0)
                kprintf("%s%d: %d.%03dMB/s transfers",
                       periph->periph_name, periph->unit_number,
                       mb, speed % 1000);
        else
                kprintf("%s%d: %dKB/s transfers", periph->periph_name,
                       periph->unit_number, speed);

        /* Report additional information about SPI connections */
        if (cts->ccb_h.status == CAM_REQ_CMP && cts->transport == XPORT_SPI) {
                struct  ccb_trans_settings_spi *spi;

                spi = &cts->xport_specific.spi;
                if (freq != 0) {
                        kprintf(" (%d.%03dMHz%s, offset %d", freq / 1000,
                               freq % 1000,
                               (spi->ppr_options & MSG_EXT_PPR_DT_REQ) != 0
                             ? " DT" : "",
                               spi->sync_offset);
                }
                if ((spi->valid & CTS_SPI_VALID_BUS_WIDTH) != 0
                 && spi->bus_width > 0) {
                        if (freq != 0) {
                                kprintf(", ");
                        } else {
                                kprintf(" (");
                        }
                        kprintf("%dbit)", 8 * (0x01 << spi->bus_width));
                } else if (freq != 0) {
                        kprintf(")");
                }
        }
        if (cts->ccb_h.status == CAM_REQ_CMP && cts->transport == XPORT_FC) {
                struct  ccb_trans_settings_fc *fc;

                fc = &cts->xport_specific.fc;
                if (fc->valid & CTS_FC_VALID_WWNN)
                        kprintf(" WWNN 0x%llx", (long long) fc->wwnn);
                if (fc->valid & CTS_FC_VALID_WWPN)
                        kprintf(" WWPN 0x%llx", (long long) fc->wwpn);
                if (fc->valid & CTS_FC_VALID_PORT)
                        kprintf(" PortID 0x%x", fc->port);
        }

        if (path->device->inq_flags & SID_CmdQue ||
            path->device->flags & CAM_DEV_TAG_AFTER_COUNT) {
                kprintf("\n%s%d: Command Queueing Enabled",
                       periph->periph_name, periph->unit_number);
        }
        kprintf("\n");

        xpt_free_ccb(&cpi->ccb_h);
        xpt_free_ccb(&cts->ccb_h);

        /*
         * We only want to print the caller's announce string if they've
         * passed one in..
         */
        if (announce_string != NULL)
                kprintf("%s%d: %s\n", periph->periph_name,
                       periph->unit_number, announce_string);
}

static dev_match_ret
xptbusmatch(struct dev_match_pattern *patterns, u_int num_patterns,
            struct cam_eb *bus)
{
        dev_match_ret retval;
        int i;

        retval = DM_RET_NONE;

        /*
         * If we aren't given something to match against, that's an error.
         */
        if (bus == NULL)
                return(DM_RET_ERROR);

        /*
         * If there are no match entries, then this bus matches no
         * matter what.
         */
        if ((patterns == NULL) || (num_patterns == 0))
                return(DM_RET_DESCEND | DM_RET_COPY);

        for (i = 0; i < num_patterns; i++) {
                struct bus_match_pattern *cur_pattern;

                /*
                 * If the pattern in question isn't for a bus node, we
                 * aren't interested.  However, we do indicate to the
                 * calling routine that we should continue descending the
                 * tree, since the user wants to match against lower-level
                 * EDT elements.
                 */
                if (patterns[i].type != DEV_MATCH_BUS) {
                        if ((retval & DM_RET_ACTION_MASK) == DM_RET_NONE)
                                retval |= DM_RET_DESCEND;
                        continue;
                }

                cur_pattern = &patterns[i].pattern.bus_pattern;

                /*
                 * If they want to match any bus node, we give them any
                 * device node.
                 */
                if (cur_pattern->flags == BUS_MATCH_ANY) {
                        /* set the copy flag */
                        retval |= DM_RET_COPY;

                        /*
                         * If we've already decided on an action, go ahead
                         * and return.
                         */
                        if ((retval & DM_RET_ACTION_MASK) != DM_RET_NONE)
                                return(retval);
                }

                /*
                 * Not sure why someone would do this...
                 */
                if (cur_pattern->flags == BUS_MATCH_NONE)
                        continue;

                if (((cur_pattern->flags & BUS_MATCH_PATH) != 0)
                 && (cur_pattern->path_id != bus->path_id))
                        continue;

                if (((cur_pattern->flags & BUS_MATCH_BUS_ID) != 0)
                 && (cur_pattern->bus_id != bus->sim->bus_id))
                        continue;

                if (((cur_pattern->flags & BUS_MATCH_UNIT) != 0)
                 && (cur_pattern->unit_number != bus->sim->unit_number))
                        continue;

                if (((cur_pattern->flags & BUS_MATCH_NAME) != 0)
                 && (strncmp(cur_pattern->dev_name, bus->sim->sim_name,
                             DEV_IDLEN) != 0))
                        continue;

                /*
                 * If we get to this point, the user definitely wants
                 * information on this bus.  So tell the caller to copy the
                 * data out.
                 */
                retval |= DM_RET_COPY;

                /*
                 * If the return action has been set to descend, then we
                 * know that we've already seen a non-bus matching
                 * expression, therefore we need to further descend the tree.
                 * This won't change by continuing around the loop, so we
                 * go ahead and return.  If we haven't seen a non-bus
                 * matching expression, we keep going around the loop until
                 * we exhaust the matching expressions.  We'll set the stop
                 * flag once we fall out of the loop.
                 */
                if ((retval & DM_RET_ACTION_MASK) == DM_RET_DESCEND)
                        return(retval);
        }

        /*
         * If the return action hasn't been set to descend yet, that means
         * we haven't seen anything other than bus matching patterns.  So
         * tell the caller to stop descending the tree -- the user doesn't
         * want to match against lower level tree elements.
         */
        if ((retval & DM_RET_ACTION_MASK) == DM_RET_NONE)
                retval |= DM_RET_STOP;

        return(retval);
}

static dev_match_ret
xptdevicematch(struct dev_match_pattern *patterns, u_int num_patterns,
               struct cam_ed *device)
{
        dev_match_ret retval;
        int i;

        retval = DM_RET_NONE;

        /*
         * If we aren't given something to match against, that's an error.
         */
        if (device == NULL)
                return(DM_RET_ERROR);

        /*
         * If there are no match entries, then this device matches no
         * matter what.
         */
        if ((patterns == NULL) || (num_patterns == 0))
                return(DM_RET_DESCEND | DM_RET_COPY);

        for (i = 0; i < num_patterns; i++) {
                struct device_match_pattern *cur_pattern;

                /*
                 * If the pattern in question isn't for a device node, we
                 * aren't interested.
                 */
                if (patterns[i].type != DEV_MATCH_DEVICE) {
                        if ((patterns[i].type == DEV_MATCH_PERIPH)
                         && ((retval & DM_RET_ACTION_MASK) == DM_RET_NONE))
                                retval |= DM_RET_DESCEND;
                        continue;
                }

                cur_pattern = &patterns[i].pattern.device_pattern;

                /*
                 * If they want to match any device node, we give them any
                 * device node.
                 */
                if (cur_pattern->flags == DEV_MATCH_ANY) {
                        /* set the copy flag */
                        retval |= DM_RET_COPY;


                        /*
                         * If we've already decided on an action, go ahead
                         * and return.
                         */
                        if ((retval & DM_RET_ACTION_MASK) != DM_RET_NONE)
                                return(retval);
                }

                /*
                 * Not sure why someone would do this...
                 */
                if (cur_pattern->flags == DEV_MATCH_NONE)
                        continue;

                if (((cur_pattern->flags & DEV_MATCH_PATH) != 0)
                 && (cur_pattern->path_id != device->target->bus->path_id))
                        continue;

                if (((cur_pattern->flags & DEV_MATCH_TARGET) != 0)
                 && (cur_pattern->target_id != device->target->target_id))
                        continue;

                if (((cur_pattern->flags & DEV_MATCH_LUN) != 0)
                 && (cur_pattern->target_lun != device->lun_id))
                        continue;

                if (((cur_pattern->flags & DEV_MATCH_INQUIRY) != 0)
                 && (cam_quirkmatch((caddr_t)&device->inq_data,
                                    (caddr_t)&cur_pattern->inq_pat,
                                    1, sizeof(cur_pattern->inq_pat),
                                    scsi_static_inquiry_match) == NULL))
                        continue;

                /*
                 * If we get to this point, the user definitely wants
                 * information on this device.  So tell the caller to copy
                 * the data out.
                 */
                retval |= DM_RET_COPY;

                /*
                 * If the return action has been set to descend, then we
                 * know that we've already seen a peripheral matching
                 * expression, therefore we need to further descend the tree.
                 * This won't change by continuing around the loop, so we
                 * go ahead and return.  If we haven't seen a peripheral
                 * matching expression, we keep going around the loop until
                 * we exhaust the matching expressions.  We'll set the stop
                 * flag once we fall out of the loop.
                 */
                if ((retval & DM_RET_ACTION_MASK) == DM_RET_DESCEND)
                        return(retval);
        }

        /*
         * If the return action hasn't been set to descend yet, that means
         * we haven't seen any peripheral matching patterns.  So tell the
         * caller to stop descending the tree -- the user doesn't want to
         * match against lower level tree elements.
         */
        if ((retval & DM_RET_ACTION_MASK) == DM_RET_NONE)
                retval |= DM_RET_STOP;

        return(retval);
}

/*
 * Match a single peripheral against any number of match patterns.
 */
static dev_match_ret
xptperiphmatch(struct dev_match_pattern *patterns, u_int num_patterns,
               struct cam_periph *periph)
{
        dev_match_ret retval;
        int i;

        /*
         * If we aren't given something to match against, that's an error.
         */
        if (periph == NULL)
                return(DM_RET_ERROR);

        /*
         * If there are no match entries, then this peripheral matches no
         * matter what.
         */
        if ((patterns == NULL) || (num_patterns == 0))
                return(DM_RET_STOP | DM_RET_COPY);

        /*
         * There aren't any nodes below a peripheral node, so there's no
         * reason to descend the tree any further.
         */
        retval = DM_RET_STOP;

        for (i = 0; i < num_patterns; i++) {
                struct periph_match_pattern *cur_pattern;

                /*
                 * If the pattern in question isn't for a peripheral, we
                 * aren't interested.
                 */
                if (patterns[i].type != DEV_MATCH_PERIPH)
                        continue;

                cur_pattern = &patterns[i].pattern.periph_pattern;

                /*
                 * If they want to match on anything, then we will do so.
                 */
                if (cur_pattern->flags == PERIPH_MATCH_ANY) {
                        /* set the copy flag */
                        retval |= DM_RET_COPY;

                        /*
                         * We've already set the return action to stop,
                         * since there are no nodes below peripherals in
                         * the tree.
                         */
                        return(retval);
                }

                /*
                 * Not sure why someone would do this...
                 */
                if (cur_pattern->flags == PERIPH_MATCH_NONE)
                        continue;

                if (((cur_pattern->flags & PERIPH_MATCH_PATH) != 0)
                 && (cur_pattern->path_id != periph->path->bus->path_id))
                        continue;

                /*
                 * For the target and lun id's, we have to make sure the
                 * target and lun pointers aren't NULL.  The xpt peripheral
                 * has a wildcard target and device.
                 */
                if (((cur_pattern->flags & PERIPH_MATCH_TARGET) != 0)
                 && ((periph->path->target == NULL)
                 ||(cur_pattern->target_id != periph->path->target->target_id)))
                        continue;

                if (((cur_pattern->flags & PERIPH_MATCH_LUN) != 0)
                 && ((periph->path->device == NULL)
                 || (cur_pattern->target_lun != periph->path->device->lun_id)))
                        continue;

                if (((cur_pattern->flags & PERIPH_MATCH_UNIT) != 0)
                 && (cur_pattern->unit_number != periph->unit_number))
                        continue;

                if (((cur_pattern->flags & PERIPH_MATCH_NAME) != 0)
                 && (strncmp(cur_pattern->periph_name, periph->periph_name,
                             DEV_IDLEN) != 0))
                        continue;

                /*
                 * If we get to this point, the user definitely wants
                 * information on this peripheral.  So tell the caller to
                 * copy the data out.
                 */
                retval |= DM_RET_COPY;

                /*
                 * The return action has already been set to stop, since
                 * peripherals don't have any nodes below them in the EDT.
                 */
                return(retval);
        }

        /*
         * If we get to this point, the peripheral that was passed in
         * doesn't match any of the patterns.
         */
        return(retval);
}

static int
xptedtbusfunc(struct cam_eb *bus, void *arg)
{
        struct ccb_dev_match *cdm;
        dev_match_ret retval;

        cdm = (struct ccb_dev_match *)arg;

        /*
         * If our position is for something deeper in the tree, that means
         * that we've already seen this node.  So, we keep going down.
         */
        if ((cdm->pos.position_type & CAM_DEV_POS_BUS)
         && (cdm->pos.cookie.bus == bus)
         && (cdm->pos.position_type & CAM_DEV_POS_TARGET)
         && (cdm->pos.cookie.target != NULL))
                retval = DM_RET_DESCEND;
        else
                retval = xptbusmatch(cdm->patterns, cdm->num_patterns, bus);

        /*
         * If we got an error, bail out of the search.
         */
        if ((retval & DM_RET_ACTION_MASK) == DM_RET_ERROR) {
                cdm->status = CAM_DEV_MATCH_ERROR;
                return(0);
        }

        /*
         * If the copy flag is set, copy this bus out.
         */
        if (retval & DM_RET_COPY) {
                int spaceleft, j;

                spaceleft = cdm->match_buf_len - (cdm->num_matches *
                        sizeof(struct dev_match_result));

                /*
                 * If we don't have enough space to put in another
                 * match result, save our position and tell the
                 * user there are more devices to check.
                 */
                if (spaceleft < sizeof(struct dev_match_result)) {
                        bzero(&cdm->pos, sizeof(cdm->pos));
                        cdm->pos.position_type =
                                CAM_DEV_POS_EDT | CAM_DEV_POS_BUS;

                        cdm->pos.cookie.bus = bus;
                        cdm->pos.generations[CAM_BUS_GENERATION]=
                                xsoftc.bus_generation;
                        cdm->status = CAM_DEV_MATCH_MORE;
                        return(0);
                }
                j = cdm->num_matches;
                cdm->num_matches++;
                cdm->matches[j].type = DEV_MATCH_BUS;
                cdm->matches[j].result.bus_result.path_id = bus->path_id;
                cdm->matches[j].result.bus_result.bus_id = bus->sim->bus_id;
                cdm->matches[j].result.bus_result.unit_number =
                        bus->sim->unit_number;
                strncpy(cdm->matches[j].result.bus_result.dev_name,
                        bus->sim->sim_name, DEV_IDLEN);
        }

        /*
         * If the user is only interested in busses, there's no
         * reason to descend to the next level in the tree.
         */
        if ((retval & DM_RET_ACTION_MASK) == DM_RET_STOP)
                return(1);

        /*
         * If there is a target generation recorded, check it to
         * make sure the target list hasn't changed.
         */
        if ((cdm->pos.position_type & CAM_DEV_POS_BUS)
         && (bus == cdm->pos.cookie.bus)
         && (cdm->pos.position_type & CAM_DEV_POS_TARGET)
         && (cdm->pos.generations[CAM_TARGET_GENERATION] != 0)
         && (cdm->pos.generations[CAM_TARGET_GENERATION] !=
             bus->generation)) {
                cdm->status = CAM_DEV_MATCH_LIST_CHANGED;
                return(0);
        }

        if ((cdm->pos.position_type & CAM_DEV_POS_BUS)
         && (cdm->pos.cookie.bus == bus)
         && (cdm->pos.position_type & CAM_DEV_POS_TARGET)
         && (cdm->pos.cookie.target != NULL))
                return(xpttargettraverse(bus,
                                        (struct cam_et *)cdm->pos.cookie.target,
                                         xptedttargetfunc, arg));
        else
                return(xpttargettraverse(bus, NULL, xptedttargetfunc, arg));
}

static int
xptedttargetfunc(struct cam_et *target, void *arg)
{
        struct ccb_dev_match *cdm;

        cdm = (struct ccb_dev_match *)arg;

        /*
         * If there is a device list generation recorded, check it to
         * make sure the device list hasn't changed.
         */
        if ((cdm->pos.position_type & CAM_DEV_POS_BUS)
         && (cdm->pos.cookie.bus == target->bus)
         && (cdm->pos.position_type & CAM_DEV_POS_TARGET)
         && (cdm->pos.cookie.target == target)
         && (cdm->pos.position_type & CAM_DEV_POS_DEVICE)
         && (cdm->pos.generations[CAM_DEV_GENERATION] != 0)
         && (cdm->pos.generations[CAM_DEV_GENERATION] !=
             target->generation)) {
                cdm->status = CAM_DEV_MATCH_LIST_CHANGED;
                return(0);
        }

        if ((cdm->pos.position_type & CAM_DEV_POS_BUS)
         && (cdm->pos.cookie.bus == target->bus)
         && (cdm->pos.position_type & CAM_DEV_POS_TARGET)
         && (cdm->pos.cookie.target == target)
         && (cdm->pos.position_type & CAM_DEV_POS_DEVICE)
         && (cdm->pos.cookie.device != NULL))
                return(xptdevicetraverse(target,
                                        (struct cam_ed *)cdm->pos.cookie.device,
                                         xptedtdevicefunc, arg));
        else
                return(xptdevicetraverse(target, NULL, xptedtdevicefunc, arg));
}

static int
xptedtdevicefunc(struct cam_ed *device, void *arg)
{

        struct ccb_dev_match *cdm;
        dev_match_ret retval;

        cdm = (struct ccb_dev_match *)arg;

        /*
         * If our position is for something deeper in the tree, that means
         * that we've already seen this node.  So, we keep going down.
         */
        if ((cdm->pos.position_type & CAM_DEV_POS_DEVICE)
         && (cdm->pos.cookie.device == device)
         && (cdm->pos.position_type & CAM_DEV_POS_PERIPH)
         && (cdm->pos.cookie.periph != NULL))
                retval = DM_RET_DESCEND;
        else
                retval = xptdevicematch(cdm->patterns, cdm->num_patterns,
                                        device);

        if ((retval & DM_RET_ACTION_MASK) == DM_RET_ERROR) {
                cdm->status = CAM_DEV_MATCH_ERROR;
                return(0);
        }

        /*
         * If the copy flag is set, copy this device out.
         */
        if (retval & DM_RET_COPY) {
                int spaceleft, j;

                spaceleft = cdm->match_buf_len - (cdm->num_matches *
                        sizeof(struct dev_match_result));

                /*
                 * If we don't have enough space to put in another
                 * match result, save our position and tell the
                 * user there are more devices to check.
                 */
                if (spaceleft < sizeof(struct dev_match_result)) {
                        bzero(&cdm->pos, sizeof(cdm->pos));
                        cdm->pos.position_type =
                                CAM_DEV_POS_EDT | CAM_DEV_POS_BUS |
                                CAM_DEV_POS_TARGET | CAM_DEV_POS_DEVICE;

                        cdm->pos.cookie.bus = device->target->bus;
                        cdm->pos.generations[CAM_BUS_GENERATION]=
                                xsoftc.bus_generation;
                        cdm->pos.cookie.target = device->target;
                        cdm->pos.generations[CAM_TARGET_GENERATION] =
                                device->target->bus->generation;
                        cdm->pos.cookie.device = device;
                        cdm->pos.generations[CAM_DEV_GENERATION] =
                                device->target->generation;
                        cdm->status = CAM_DEV_MATCH_MORE;
                        return(0);
                }
                j = cdm->num_matches;
                cdm->num_matches++;
                cdm->matches[j].type = DEV_MATCH_DEVICE;
                cdm->matches[j].result.device_result.path_id =
                        device->target->bus->path_id;
                cdm->matches[j].result.device_result.target_id =
                        device->target->target_id;
                cdm->matches[j].result.device_result.target_lun =
                        device->lun_id;
                bcopy(&device->inq_data,
                      &cdm->matches[j].result.device_result.inq_data,
                      sizeof(struct scsi_inquiry_data));

                /* Let the user know whether this device is unconfigured */
                if (device->flags & CAM_DEV_UNCONFIGURED)
                        cdm->matches[j].result.device_result.flags =
                                DEV_RESULT_UNCONFIGURED;
                else
                        cdm->matches[j].result.device_result.flags =
                                DEV_RESULT_NOFLAG;
        }

        /*
         * If the user isn't interested in peripherals, don't descend
         * the tree any further.
         */
        if ((retval & DM_RET_ACTION_MASK) == DM_RET_STOP)
                return(1);

        /*
         * If there is a peripheral list generation recorded, make sure
         * it hasn't changed.
         */
        if ((cdm->pos.position_type & CAM_DEV_POS_BUS)
         && (device->target->bus == cdm->pos.cookie.bus)
         && (cdm->pos.position_type & CAM_DEV_POS_TARGET)
         && (device->target == cdm->pos.cookie.target)
         && (cdm->pos.position_type & CAM_DEV_POS_DEVICE)
         && (device == cdm->pos.cookie.device)
         && (cdm->pos.position_type & CAM_DEV_POS_PERIPH)
         && (cdm->pos.generations[CAM_PERIPH_GENERATION] != 0)
         && (cdm->pos.generations[CAM_PERIPH_GENERATION] !=
             device->generation)){
                cdm->status = CAM_DEV_MATCH_LIST_CHANGED;
                return(0);
        }

        if ((cdm->pos.position_type & CAM_DEV_POS_BUS)
         && (cdm->pos.cookie.bus == device->target->bus)
         && (cdm->pos.position_type & CAM_DEV_POS_TARGET)
         && (cdm->pos.cookie.target == device->target)
         && (cdm->pos.position_type & CAM_DEV_POS_DEVICE)
         && (cdm->pos.cookie.device == device)
         && (cdm->pos.position_type & CAM_DEV_POS_PERIPH)
         && (cdm->pos.cookie.periph != NULL))
                return(xptperiphtraverse(device,
                                (struct cam_periph *)cdm->pos.cookie.periph,
                                xptedtperiphfunc, arg));
        else
                return(xptperiphtraverse(device, NULL, xptedtperiphfunc, arg));
}

static int
xptedtperiphfunc(struct cam_periph *periph, void *arg)
{
        struct ccb_dev_match *cdm;
        dev_match_ret retval;

        cdm = (struct ccb_dev_match *)arg;

        retval = xptperiphmatch(cdm->patterns, cdm->num_patterns, periph);

        if ((retval & DM_RET_ACTION_MASK) == DM_RET_ERROR) {
                cdm->status = CAM_DEV_MATCH_ERROR;
                return(0);
        }

        /*
         * If the copy flag is set, copy this peripheral out.
         */
        if (retval & DM_RET_COPY) {
                int spaceleft, j;

                spaceleft = cdm->match_buf_len - (cdm->num_matches *
                        sizeof(struct dev_match_result));

                /*
                 * If we don't have enough space to put in another
                 * match result, save our position and tell the
                 * user there are more devices to check.
                 */
                if (spaceleft < sizeof(struct dev_match_result)) {
                        bzero(&cdm->pos, sizeof(cdm->pos));
                        cdm->pos.position_type =
                                CAM_DEV_POS_EDT | CAM_DEV_POS_BUS |
                                CAM_DEV_POS_TARGET | CAM_DEV_POS_DEVICE |
                                CAM_DEV_POS_PERIPH;

                        cdm->pos.cookie.bus = periph->path->bus;
                        cdm->pos.generations[CAM_BUS_GENERATION]=
                                xsoftc.bus_generation;
                        cdm->pos.cookie.target = periph->path->target;
                        cdm->pos.generations[CAM_TARGET_GENERATION] =
                                periph->path->bus->generation;
                        cdm->pos.cookie.device = periph->path->device;
                        cdm->pos.generations[CAM_DEV_GENERATION] =
                                periph->path->target->generation;
                        cdm->pos.cookie.periph = periph;
                        cdm->pos.generations[CAM_PERIPH_GENERATION] =
                                periph->path->device->generation;
                        cdm->status = CAM_DEV_MATCH_MORE;
                        return(0);
                }

                j = cdm->num_matches;
                cdm->num_matches++;
                cdm->matches[j].type = DEV_MATCH_PERIPH;
                cdm->matches[j].result.periph_result.path_id =
                        periph->path->bus->path_id;
                cdm->matches[j].result.periph_result.target_id =
                        periph->path->target->target_id;
                cdm->matches[j].result.periph_result.target_lun =
                        periph->path->device->lun_id;
                cdm->matches[j].result.periph_result.unit_number =
                        periph->unit_number;
                strncpy(cdm->matches[j].result.periph_result.periph_name,
                        periph->periph_name, DEV_IDLEN);
        }

        return(1);
}

static int
xptedtmatch(struct ccb_dev_match *cdm)
{
        int ret;

        cdm->num_matches = 0;

        /*
         * Check the bus list generation.  If it has changed, the user
         * needs to reset everything and start over.
         */
        if ((cdm->pos.position_type & CAM_DEV_POS_BUS)
         && (cdm->pos.generations[CAM_BUS_GENERATION] != 0)
         && (cdm->pos.generations[CAM_BUS_GENERATION] != xsoftc.bus_generation)) {
                cdm->status = CAM_DEV_MATCH_LIST_CHANGED;
                return(0);
        }

        if ((cdm->pos.position_type & CAM_DEV_POS_BUS)
         && (cdm->pos.cookie.bus != NULL))
                ret = xptbustraverse((struct cam_eb *)cdm->pos.cookie.bus,
                                     xptedtbusfunc, cdm);
        else
                ret = xptbustraverse(NULL, xptedtbusfunc, cdm);

        /*
         * If we get back 0, that means that we had to stop before fully
         * traversing the EDT.  It also means that one of the subroutines
         * has set the status field to the proper value.  If we get back 1,
         * we've fully traversed the EDT and copied out any matching entries.
         */
        if (ret == 1)
                cdm->status = CAM_DEV_MATCH_LAST;

        return(ret);
}

static int
xptplistpdrvfunc(struct periph_driver **pdrv, void *arg)
{
        struct ccb_dev_match *cdm;

        cdm = (struct ccb_dev_match *)arg;

        if ((cdm->pos.position_type & CAM_DEV_POS_PDPTR)
         && (cdm->pos.cookie.pdrv == pdrv)
         && (cdm->pos.position_type & CAM_DEV_POS_PERIPH)
         && (cdm->pos.generations[CAM_PERIPH_GENERATION] != 0)
         && (cdm->pos.generations[CAM_PERIPH_GENERATION] !=
             (*pdrv)->generation)) {
                cdm->status = CAM_DEV_MATCH_LIST_CHANGED;
                return(0);
        }

        if ((cdm->pos.position_type & CAM_DEV_POS_PDPTR)
         && (cdm->pos.cookie.pdrv == pdrv)
         && (cdm->pos.position_type & CAM_DEV_POS_PERIPH)
         && (cdm->pos.cookie.periph != NULL))
                return(xptpdperiphtraverse(pdrv,
                                (struct cam_periph *)cdm->pos.cookie.periph,
                                xptplistperiphfunc, arg));
        else
                return(xptpdperiphtraverse(pdrv, NULL,xptplistperiphfunc, arg));
}

static int
xptplistperiphfunc(struct cam_periph *periph, void *arg)
{
        struct ccb_dev_match *cdm;
        dev_match_ret retval;

        cdm = (struct ccb_dev_match *)arg;

        retval = xptperiphmatch(cdm->patterns, cdm->num_patterns, periph);

        if ((retval & DM_RET_ACTION_MASK) == DM_RET_ERROR) {
                cdm->status = CAM_DEV_MATCH_ERROR;
                return(0);
        }

        /*
         * If the copy flag is set, copy this peripheral out.
         */
        if (retval & DM_RET_COPY) {
                int spaceleft, j;

                spaceleft = cdm->match_buf_len - (cdm->num_matches *
                        sizeof(struct dev_match_result));

                /*
                 * If we don't have enough space to put in another
                 * match result, save our position and tell the
                 * user there are more devices to check.
                 */
                if (spaceleft < sizeof(struct dev_match_result)) {
                        struct periph_driver **pdrv;

                        pdrv = NULL;
                        bzero(&cdm->pos, sizeof(cdm->pos));
                        cdm->pos.position_type =
                                CAM_DEV_POS_PDRV | CAM_DEV_POS_PDPTR |
                                CAM_DEV_POS_PERIPH;

                        /*
                         * This may look a bit non-sensical, but it is
                         * actually quite logical.  There are very few
                         * peripheral drivers, and bloating every peripheral
                         * structure with a pointer back to its parent
                         * peripheral driver linker set entry would cost
                         * more in the long run than doing this quick lookup.
                         */
                        for (pdrv = periph_drivers; *pdrv != NULL; pdrv++) {
                                if (strcmp((*pdrv)->driver_name,
                                    periph->periph_name) == 0)
                                        break;
                        }

                        if (*pdrv == NULL) {
                                cdm->status = CAM_DEV_MATCH_ERROR;
                                return(0);
                        }

                        cdm->pos.cookie.pdrv = pdrv;
                        /*
                         * The periph generation slot does double duty, as
                         * does the periph pointer slot.  They are used for
                         * both edt and pdrv lookups and positioning.
                         */
                        cdm->pos.cookie.periph = periph;
                        cdm->pos.generations[CAM_PERIPH_GENERATION] =
                                (*pdrv)->generation;
                        cdm->status = CAM_DEV_MATCH_MORE;
                        return(0);
                }

                j = cdm->num_matches;
                cdm->num_matches++;
                cdm->matches[j].type = DEV_MATCH_PERIPH;
                cdm->matches[j].result.periph_result.path_id =
                        periph->path->bus->path_id;

                /*
                 * The transport layer peripheral doesn't have a target or
                 * lun.
                 */
                if (periph->path->target)
                        cdm->matches[j].result.periph_result.target_id =
                                periph->path->target->target_id;
                else
                        cdm->matches[j].result.periph_result.target_id = -1;

                if (periph->path->device)
                        cdm->matches[j].result.periph_result.target_lun =
                                periph->path->device->lun_id;
                else
                        cdm->matches[j].result.periph_result.target_lun = -1;

                cdm->matches[j].result.periph_result.unit_number =
                        periph->unit_number;
                strncpy(cdm->matches[j].result.periph_result.periph_name,
                        periph->periph_name, DEV_IDLEN);
        }

        return(1);
}

static int
xptperiphlistmatch(struct ccb_dev_match *cdm)
{
        int ret;

        cdm->num_matches = 0;

        /*
         * At this point in the edt traversal function, we check the bus
         * list generation to make sure that no busses have been added or
         * removed since the user last sent a XPT_DEV_MATCH ccb through.
         * For the peripheral driver list traversal function, however, we
         * don't have to worry about new peripheral driver types coming or
         * going; they're in a linker set, and therefore can't change
         * without a recompile.
         */

        if ((cdm->pos.position_type & CAM_DEV_POS_PDPTR)
         && (cdm->pos.cookie.pdrv != NULL))
                ret = xptpdrvtraverse(
                                (struct periph_driver **)cdm->pos.cookie.pdrv,
                                xptplistpdrvfunc, cdm);
        else
                ret = xptpdrvtraverse(NULL, xptplistpdrvfunc, cdm);

        /*
         * If we get back 0, that means that we had to stop before fully
         * traversing the peripheral driver tree.  It also means that one of
         * the subroutines has set the status field to the proper value.  If
         * we get back 1, we've fully traversed the EDT and copied out any
         * matching entries.
         */
        if (ret == 1)
                cdm->status = CAM_DEV_MATCH_LAST;

        return(ret);
}

static int
xptbustraverse(struct cam_eb *start_bus, xpt_busfunc_t *tr_func, void *arg)
{
        struct cam_eb *bus, *next_bus;
        int retval;

        retval = 1;

        lockmgr(&xsoftc.xpt_topo_lock, LK_EXCLUSIVE);
        for (bus = (start_bus ? start_bus : TAILQ_FIRST(&xsoftc.xpt_busses));
             bus != NULL;
             bus = next_bus) {
                next_bus = TAILQ_NEXT(bus, links);

                lockmgr(&xsoftc.xpt_topo_lock, LK_RELEASE);
                CAM_SIM_LOCK(bus->sim);
                retval = tr_func(bus, arg);
                CAM_SIM_UNLOCK(bus->sim);
                if (retval == 0)
                        return(retval);
                lockmgr(&xsoftc.xpt_topo_lock, LK_EXCLUSIVE);
        }
        lockmgr(&xsoftc.xpt_topo_lock, LK_RELEASE);

        return(retval);
}

static int
xpttargettraverse(struct cam_eb *bus, struct cam_et *start_target,
                  xpt_targetfunc_t *tr_func, void *arg)
{
        struct cam_et *target, *next_target;
        int retval;

        retval = 1;
        for (target = (start_target ? start_target :
                       TAILQ_FIRST(&bus->et_entries));
             target != NULL; target = next_target) {

                next_target = TAILQ_NEXT(target, links);

                retval = tr_func(target, arg);

                if (retval == 0)
                        return(retval);
        }

        return(retval);
}

static int
xptdevicetraverse(struct cam_et *target, struct cam_ed *start_device,
                  xpt_devicefunc_t *tr_func, void *arg)
{
        struct cam_ed *device, *next_device;
        int retval;

        retval = 1;
        for (device = (start_device ? start_device :
                       TAILQ_FIRST(&target->ed_entries));
             device != NULL;
             device = next_device) {

                next_device = TAILQ_NEXT(device, links);

                retval = tr_func(device, arg);

                if (retval == 0)
                        return(retval);
        }

        return(retval);
}

static int
xptperiphtraverse(struct cam_ed *device, struct cam_periph *start_periph,
                  xpt_periphfunc_t *tr_func, void *arg)
{
        struct cam_periph *periph, *next_periph;
        int retval;

        retval = 1;

        for (periph = (start_periph ? start_periph :
                       SLIST_FIRST(&device->periphs));
             periph != NULL;
             periph = next_periph) {

                next_periph = SLIST_NEXT(periph, periph_links);

                retval = tr_func(periph, arg);
                if (retval == 0)
                        return(retval);
        }

        return(retval);
}

static int
xptpdrvtraverse(struct periph_driver **start_pdrv,
                xpt_pdrvfunc_t *tr_func, void *arg)
{
        struct periph_driver **pdrv;
        int retval;

        retval = 1;

        /*
         * We don't traverse the peripheral driver list like we do the
         * other lists, because it is a linker set, and therefore cannot be
         * changed during runtime.  If the peripheral driver list is ever
         * re-done to be something other than a linker set (i.e. it can
         * change while the system is running), the list traversal should
         * be modified to work like the other traversal functions.
         */
        for (pdrv = (start_pdrv ? start_pdrv : periph_drivers);
             *pdrv != NULL; pdrv++) {
                retval = tr_func(pdrv, arg);

                if (retval == 0)
                        return(retval);
        }

        return(retval);
}

static int
xptpdperiphtraverse(struct periph_driver **pdrv,
                    struct cam_periph *start_periph,
                    xpt_periphfunc_t *tr_func, void *arg)
{
        struct cam_periph *periph, *next_periph;
        int retval;

        retval = 1;

        for (periph = (start_periph ? start_periph :
             TAILQ_FIRST(&(*pdrv)->units)); periph != NULL;
             periph = next_periph) {

                next_periph = TAILQ_NEXT(periph, unit_links);

                retval = tr_func(periph, arg);
                if (retval == 0)
                        return(retval);
        }
        return(retval);
}

static int
xptdefbusfunc(struct cam_eb *bus, void *arg)
{
        struct xpt_traverse_config *tr_config;

        tr_config = (struct xpt_traverse_config *)arg;

        if (tr_config->depth == XPT_DEPTH_BUS) {
                xpt_busfunc_t *tr_func;

                tr_func = (xpt_busfunc_t *)tr_config->tr_func;

                return(tr_func(bus, tr_config->tr_arg));
        } else
                return(xpttargettraverse(bus, NULL, xptdeftargetfunc, arg));
}

static int
xptdeftargetfunc(struct cam_et *target, void *arg)
{
        struct xpt_traverse_config *tr_config;

        tr_config = (struct xpt_traverse_config *)arg;

        if (tr_config->depth == XPT_DEPTH_TARGET) {
                xpt_targetfunc_t *tr_func;

                tr_func = (xpt_targetfunc_t *)tr_config->tr_func;

                return(tr_func(target, tr_config->tr_arg));
        } else
                return(xptdevicetraverse(target, NULL, xptdefdevicefunc, arg));
}

static int
xptdefdevicefunc(struct cam_ed *device, void *arg)
{
        struct xpt_traverse_config *tr_config;

        tr_config = (struct xpt_traverse_config *)arg;

        if (tr_config->depth == XPT_DEPTH_DEVICE) {
                xpt_devicefunc_t *tr_func;

                tr_func = (xpt_devicefunc_t *)tr_config->tr_func;

                return(tr_func(device, tr_config->tr_arg));
        } else
                return(xptperiphtraverse(device, NULL, xptdefperiphfunc, arg));
}

static int
xptdefperiphfunc(struct cam_periph *periph, void *arg)
{
        struct xpt_traverse_config *tr_config;
        xpt_periphfunc_t *tr_func;

        tr_config = (struct xpt_traverse_config *)arg;

        tr_func = (xpt_periphfunc_t *)tr_config->tr_func;

        /*
         * Unlike the other default functions, we don't check for depth
         * here.  The peripheral driver level is the last level in the EDT,
         * so if we're here, we should execute the function in question.
         */
        return(tr_func(periph, tr_config->tr_arg));
}

/*
 * Execute the given function for every bus in the EDT.
 */
static int
xpt_for_all_busses(xpt_busfunc_t *tr_func, void *arg)
{
        struct xpt_traverse_config tr_config;

        tr_config.depth = XPT_DEPTH_BUS;
        tr_config.tr_func = tr_func;
        tr_config.tr_arg = arg;

        return(xptbustraverse(NULL, xptdefbusfunc, &tr_config));
}

/*
 * Execute the given function for every device in the EDT.
 */
static int
xpt_for_all_devices(xpt_devicefunc_t *tr_func, void *arg)
{
        struct xpt_traverse_config tr_config;

        tr_config.depth = XPT_DEPTH_DEVICE;
        tr_config.tr_func = tr_func;
        tr_config.tr_arg = arg;

        return(xptbustraverse(NULL, xptdefbusfunc, &tr_config));
}

static int
xptsetasyncfunc(struct cam_ed *device, void *arg)
{
        struct cam_path path;
        struct ccb_getdev *cgd;
        struct async_node *cur_entry;

        cur_entry = (struct async_node *)arg;

        /*
         * Don't report unconfigured devices (Wildcard devs,
         * devices only for target mode, device instances
         * that have been invalidated but are waiting for
         * their last reference count to be released).
         */
        if ((device->flags & CAM_DEV_UNCONFIGURED) != 0)
                return (1);

        xpt_compile_path(&path,
                         NULL,
                         device->target->bus->path_id,
                         device->target->target_id,
                         device->lun_id);

        cgd = &xpt_alloc_ccb()->cgd;
        xpt_setup_ccb(&cgd->ccb_h, &path, /*priority*/1);
        cgd->ccb_h.func_code = XPT_GDEV_TYPE;
        xpt_action((union ccb *)cgd);
        cur_entry->callback(cur_entry->callback_arg,
                            AC_FOUND_DEVICE,
                            &path, cgd);
        xpt_release_path(&path);
        xpt_free_ccb(&cgd->ccb_h);

        return(1);
}

static int
xptsetasyncbusfunc(struct cam_eb *bus, void *arg)
{
        struct cam_path path;
        struct ccb_pathinq *cpi;
        struct async_node *cur_entry;

        cur_entry = (struct async_node *)arg;

        xpt_compile_path(&path, /*periph*/NULL,
                         bus->sim->path_id,
                         CAM_TARGET_WILDCARD,
                         CAM_LUN_WILDCARD);
        cpi = &xpt_alloc_ccb()->cpi;
        xpt_setup_ccb(&cpi->ccb_h, &path, /*priority*/1);
        cpi->ccb_h.func_code = XPT_PATH_INQ;
        xpt_action((union ccb *)cpi);
        cur_entry->callback(cur_entry->callback_arg,
                            AC_PATH_REGISTERED,
                            &path, cpi);
        xpt_release_path(&path);
        xpt_free_ccb(&cpi->ccb_h);

        return(1);
}

static void
xpt_action_sasync_cb(void *context, int pending)
{
        struct async_node *cur_entry;
        struct xpt_task *task;
        uint32_t added;

        task = (struct xpt_task *)context;
        cur_entry = (struct async_node *)task->data1;
        added = task->data2;

        if ((added & AC_FOUND_DEVICE) != 0) {
                /*
                 * Get this peripheral up to date with all
                 * the currently existing devices.
                 */
                xpt_for_all_devices(xptsetasyncfunc, cur_entry);
        }
        if ((added & AC_PATH_REGISTERED) != 0) {
                /*
                 * Get this peripheral up to date with all
                 * the currently existing busses.
                 */
                xpt_for_all_busses(xptsetasyncbusfunc, cur_entry);
        }
        kfree(task, M_CAMXPT);
}

void
xpt_action(union ccb *start_ccb)
{
        CAM_DEBUG(start_ccb->ccb_h.path, CAM_DEBUG_TRACE, ("xpt_action\n"));

        start_ccb->ccb_h.status = CAM_REQ_INPROG;

        switch (start_ccb->ccb_h.func_code) {
        case XPT_SCSI_IO:
        case XPT_TRIM:
        {
                struct cam_ed *device;
#ifdef CAMDEBUG
                char cdb_str[(SCSI_MAX_CDBLEN * 3) + 1];
                struct cam_path *path;

                path = start_ccb->ccb_h.path;
#endif

                /*
                 * For the sake of compatibility with SCSI-1
                 * devices that may not understand the identify
                 * message, we include lun information in the
                 * second byte of all commands.  SCSI-1 specifies
                 * that luns are a 3 bit value and reserves only 3
                 * bits for lun information in the CDB.  Later
                 * revisions of the SCSI spec allow for more than 8
                 * luns, but have deprecated lun information in the
                 * CDB.  So, if the lun won't fit, we must omit.
                 *
                 * Also be aware that during initial probing for devices,
                 * the inquiry information is unknown but initialized to 0.
                 * This means that this code will be exercised while probing
                 * devices with an ANSI revision greater than 2.
                 */
                device = start_ccb->ccb_h.path->device;
                if (device->protocol_version <= SCSI_REV_2
                 && start_ccb->ccb_h.target_lun < 8
                 && (start_ccb->ccb_h.flags & CAM_CDB_POINTER) == 0) {

                        start_ccb->csio.cdb_io.cdb_bytes[1] |=
                            start_ccb->ccb_h.target_lun << 5;
                }
                start_ccb->csio.scsi_status = SCSI_STATUS_OK;
                CAM_DEBUG(path, CAM_DEBUG_CDB,("%s. CDB: %s\n",
                          scsi_op_desc(start_ccb->csio.cdb_io.cdb_bytes[0],
                                       &path->device->inq_data),
                          scsi_cdb_string(start_ccb->csio.cdb_io.cdb_bytes,
                                          cdb_str, sizeof(cdb_str))));
                /* FALLTHROUGH */
        }
        case XPT_TARGET_IO:
        case XPT_CONT_TARGET_IO:
                start_ccb->csio.sense_resid = 0;
                start_ccb->csio.resid = 0;
                /* FALLTHROUGH */
        case XPT_RESET_DEV:
        case XPT_ENG_EXEC:
        {
                struct cam_path *path;
                struct cam_sim *sim;
                int runq;

                path = start_ccb->ccb_h.path;

                sim = path->bus->sim;
                if (sim == &cam_dead_sim) {
                        /* The SIM has gone; just execute the CCB directly. */
                        cam_ccbq_send_ccb(&path->device->ccbq, start_ccb);
                        (*(sim->sim_action))(sim, start_ccb);
                        break;
                }

                cam_ccbq_insert_ccb(&path->device->ccbq, start_ccb);
                if (path->device->qfrozen_cnt == 0)
                        runq = xpt_schedule_dev_sendq(path->bus, path->device);
                else
                        runq = 0;
                if (runq != 0)
                        xpt_run_dev_sendq(path->bus);
                break;
        }
        case XPT_SET_TRAN_SETTINGS:
        {
                xpt_set_transfer_settings(&start_ccb->cts,
                                          start_ccb->ccb_h.path->device,
                                          /*async_update*/FALSE);
                break;
        }
        case XPT_CALC_GEOMETRY:
        {
                struct cam_sim *sim;

                /* Filter out garbage */
                if (start_ccb->ccg.block_size == 0
                 || start_ccb->ccg.volume_size == 0) {
                        start_ccb->ccg.cylinders = 0;
                        start_ccb->ccg.heads = 0;
                        start_ccb->ccg.secs_per_track = 0;
                        start_ccb->ccb_h.status = CAM_REQ_CMP;
                        break;
                }
                sim = start_ccb->ccb_h.path->bus->sim;
                (*(sim->sim_action))(sim, start_ccb);
                break;
        }
        case XPT_ABORT:
        {
                union ccb* abort_ccb;

                abort_ccb = start_ccb->cab.abort_ccb;
                if (XPT_FC_IS_DEV_QUEUED(abort_ccb)) {

                        if (abort_ccb->ccb_h.pinfo.index >= 0) {
                                struct cam_ccbq *ccbq;

                                ccbq = &abort_ccb->ccb_h.path->device->ccbq;
                                cam_ccbq_remove_ccb(ccbq, abort_ccb);
                                abort_ccb->ccb_h.status =
                                    CAM_REQ_ABORTED|CAM_DEV_QFRZN;
                                xpt_freeze_devq(abort_ccb->ccb_h.path, 1);
                                xpt_done(abort_ccb);
                                start_ccb->ccb_h.status = CAM_REQ_CMP;
                                break;
                        }
                        if (abort_ccb->ccb_h.pinfo.index == CAM_UNQUEUED_INDEX
                         && (abort_ccb->ccb_h.status & CAM_SIM_QUEUED) == 0) {
                                /*
                                 * We've caught this ccb en route to
                                 * the SIM.  Flag it for abort and the
                                 * SIM will do so just before starting
                                 * real work on the CCB.
                                 */
                                abort_ccb->ccb_h.status =
                                    CAM_REQ_ABORTED|CAM_DEV_QFRZN;
                                xpt_freeze_devq(abort_ccb->ccb_h.path, 1);
                                start_ccb->ccb_h.status = CAM_REQ_CMP;
                                break;
                        }
                }
                if (XPT_FC_IS_QUEUED(abort_ccb)
                 && (abort_ccb->ccb_h.pinfo.index == CAM_DONEQ_INDEX)) {
                        /*
                         * It's already completed but waiting
                         * for our SWI to get to it.
                         */
                        start_ccb->ccb_h.status = CAM_UA_ABORT;
                        break;
                }
                /*
                 * If we weren't able to take care of the abort request
                 * in the XPT, pass the request down to the SIM for processing.
                 */
                /* FALLTHROUGH */
        }
        case XPT_ACCEPT_TARGET_IO:
        case XPT_EN_LUN:
        case XPT_IMMED_NOTIFY:
        case XPT_NOTIFY_ACK:
        case XPT_GET_TRAN_SETTINGS:
        case XPT_RESET_BUS:
        {
                struct cam_sim *sim;

                sim = start_ccb->ccb_h.path->bus->sim;
                (*(sim->sim_action))(sim, start_ccb);
                break;
        }
        case XPT_PATH_INQ:
        {
                struct cam_sim *sim;

                sim = start_ccb->ccb_h.path->bus->sim;
                (*(sim->sim_action))(sim, start_ccb);
                break;
        }
        case XPT_PATH_STATS:
                start_ccb->cpis.last_reset =
                        start_ccb->ccb_h.path->bus->last_reset;
                start_ccb->ccb_h.status = CAM_REQ_CMP;
                break;
        case XPT_GDEV_TYPE:
        {
                struct cam_ed *dev;

                dev = start_ccb->ccb_h.path->device;
                if ((dev->flags & CAM_DEV_UNCONFIGURED) != 0) {
                        start_ccb->ccb_h.status = CAM_DEV_NOT_THERE;
                } else {
                        struct ccb_getdev *cgd;

                        cgd = &start_ccb->cgd;
                        cgd->inq_data = dev->inq_data;
                        cgd->ccb_h.status = CAM_REQ_CMP;
                        cgd->serial_num_len = dev->serial_num_len;
                        if ((dev->serial_num_len > 0)
                         && (dev->serial_num != NULL))
                                bcopy(dev->serial_num, cgd->serial_num,
                                      dev->serial_num_len);
                }
                break;
        }
        case XPT_GDEV_STATS:
        {
                struct cam_ed *dev;

                dev = start_ccb->ccb_h.path->device;
                if ((dev->flags & CAM_DEV_UNCONFIGURED) != 0) {
                        start_ccb->ccb_h.status = CAM_DEV_NOT_THERE;
                } else {
                        struct ccb_getdevstats *cgds;
                        struct cam_eb *bus;
                        struct cam_et *tar;

                        cgds = &start_ccb->cgds;
                        bus = cgds->ccb_h.path->bus;
                        tar = cgds->ccb_h.path->target;
                        cgds->dev_openings = dev->ccbq.dev_openings;
                        cgds->dev_active = dev->ccbq.dev_active;
                        cgds->devq_openings = dev->ccbq.devq_openings;
                        cgds->devq_queued = dev->ccbq.queue.entries;
                        cgds->held = dev->ccbq.held;
                        cgds->last_reset = tar->last_reset;
                        cgds->maxtags = dev->quirk->maxtags;
                        cgds->mintags = dev->quirk->mintags;
                        if (timevalcmp(&tar->last_reset, &bus->last_reset, <))
                                cgds->last_reset = bus->last_reset;
                        cgds->ccb_h.status = CAM_REQ_CMP;
                }
                break;
        }
        case XPT_GDEVLIST:
        {
                struct cam_periph       *nperiph;
                struct periph_list      *periph_head;
                struct ccb_getdevlist   *cgdl;
                u_int                   i;
                struct cam_ed           *device;
                int                     found;


                found = 0;

                /*
                 * Don't want anyone mucking with our data.
                 */
                device = start_ccb->ccb_h.path->device;
                periph_head = &device->periphs;
                cgdl = &start_ccb->cgdl;

                /*
                 * Check and see if the list has changed since the user
                 * last requested a list member.  If so, tell them that the
                 * list has changed, and therefore they need to start over
                 * from the beginning.
                 */
                if ((cgdl->index != 0) &&
                    (cgdl->generation != device->generation)) {
                        cgdl->status = CAM_GDEVLIST_LIST_CHANGED;
                        break;
                }

                /*
                 * Traverse the list of peripherals and attempt to find
                 * the requested peripheral.
                 */
                for (nperiph = SLIST_FIRST(periph_head), i = 0;
                     (nperiph != NULL) && (i <= cgdl->index);
                     nperiph = SLIST_NEXT(nperiph, periph_links), i++) {
                        if (i == cgdl->index) {
                                strncpy(cgdl->periph_name,
                                        nperiph->periph_name,
                                        DEV_IDLEN);
                                cgdl->unit_number = nperiph->unit_number;
                                found = 1;
                        }
                }
                if (found == 0) {
                        cgdl->status = CAM_GDEVLIST_ERROR;
                        break;
                }

                if (nperiph == NULL)
                        cgdl->status = CAM_GDEVLIST_LAST_DEVICE;
                else
                        cgdl->status = CAM_GDEVLIST_MORE_DEVS;

                cgdl->index++;
                cgdl->generation = device->generation;

                cgdl->ccb_h.status = CAM_REQ_CMP;
                break;
        }
        case XPT_DEV_MATCH:
        {
                dev_pos_type position_type;
                struct ccb_dev_match *cdm;
                int ret;

                cdm = &start_ccb->cdm;

                /*
                 * There are two ways of getting at information in the EDT.
                 * The first way is via the primary EDT tree.  It starts
                 * with a list of busses, then a list of targets on a bus,
                 * then devices/luns on a target, and then peripherals on a
                 * device/lun.  The "other" way is by the peripheral driver
                 * lists.  The peripheral driver lists are organized by
                 * peripheral driver.  (obviously)  So it makes sense to
                 * use the peripheral driver list if the user is looking
                 * for something like "da1", or all "da" devices.  If the
                 * user is looking for something on a particular bus/target
                 * or lun, it's generally better to go through the EDT tree.
                 */

                if (cdm->pos.position_type != CAM_DEV_POS_NONE)
                        position_type = cdm->pos.position_type;
                else {
                        u_int i;

                        position_type = CAM_DEV_POS_NONE;

                        for (i = 0; i < cdm->num_patterns; i++) {
                                if ((cdm->patterns[i].type == DEV_MATCH_BUS)
                                 ||(cdm->patterns[i].type == DEV_MATCH_DEVICE)){
                                        position_type = CAM_DEV_POS_EDT;
                                        break;
                                }
                        }

                        if (cdm->num_patterns == 0)
                                position_type = CAM_DEV_POS_EDT;
                        else if (position_type == CAM_DEV_POS_NONE)
                                position_type = CAM_DEV_POS_PDRV;
                }

                switch(position_type & CAM_DEV_POS_TYPEMASK) {
                case CAM_DEV_POS_EDT:
                        ret = xptedtmatch(cdm);
                        break;
                case CAM_DEV_POS_PDRV:
                        ret = xptperiphlistmatch(cdm);
                        break;
                default:
                        cdm->status = CAM_DEV_MATCH_ERROR;
                        break;
                }

                if (cdm->status == CAM_DEV_MATCH_ERROR)
                        start_ccb->ccb_h.status = CAM_REQ_CMP_ERR;
                else
                        start_ccb->ccb_h.status = CAM_REQ_CMP;

                break;
        }
        case XPT_SASYNC_CB:
        {
                struct ccb_setasync *csa;
                struct async_node *cur_entry;
                struct async_list *async_head;
                u_int32_t added;

                csa = &start_ccb->csa;
                added = csa->event_enable;
                async_head = &csa->ccb_h.path->device->asyncs;

                /*
                 * If there is already an entry for us, simply
                 * update it.
                 */
                cur_entry = SLIST_FIRST(async_head);
                while (cur_entry != NULL) {
                        if ((cur_entry->callback_arg == csa->callback_arg)
                         && (cur_entry->callback == csa->callback))
                                break;
                        cur_entry = SLIST_NEXT(cur_entry, links);
                }

                if (cur_entry != NULL) {
                        /*
                         * If the request has no flags set,
                         * remove the entry.
                         */
                        added &= ~cur_entry->event_enable;
                        if (csa->event_enable == 0) {
                                SLIST_REMOVE(async_head, cur_entry,
                                             async_node, links);
                                atomic_add_int(
                                        &csa->ccb_h.path->device->refcount, -1);
                                kfree(cur_entry, M_CAMXPT);
                        } else {
                                cur_entry->event_enable = csa->event_enable;
                        }
                } else {
                        cur_entry = kmalloc(sizeof(*cur_entry), M_CAMXPT,
                                           M_INTWAIT);
                        cur_entry->event_enable = csa->event_enable;
                        cur_entry->callback_arg = csa->callback_arg;
                        cur_entry->callback = csa->callback;
                        SLIST_INSERT_HEAD(async_head, cur_entry, links);
                        atomic_add_int(&csa->ccb_h.path->device->refcount, 1);
                }

                /*
                 * Need to decouple this operation via a taskqueue so that
                 * the locking doesn't become a mess.
                 */
                if ((added & (AC_FOUND_DEVICE | AC_PATH_REGISTERED)) != 0) {
                        struct xpt_task *task;

                        task = kmalloc(sizeof(struct xpt_task), M_CAMXPT,
                                      M_INTWAIT);

                        TASK_INIT(&task->task, 0, xpt_action_sasync_cb, task);
                        task->data1 = cur_entry;
                        task->data2 = added;
                        taskqueue_enqueue(taskqueue_thread[mycpuid],
                                          &task->task);
                }

                start_ccb->ccb_h.status = CAM_REQ_CMP;
                break;
        }
        case XPT_REL_SIMQ:
        {
                struct ccb_relsim *crs;
                struct cam_ed *dev;

                crs = &start_ccb->crs;
                dev = crs->ccb_h.path->device;
                if (dev == NULL) {

                        crs->ccb_h.status = CAM_DEV_NOT_THERE;
                        break;
                }

                if ((crs->release_flags & RELSIM_ADJUST_OPENINGS) != 0) {

                        if (INQ_DATA_TQ_ENABLED(&dev->inq_data)) {
                                /* Don't ever go below one opening */
                                if (crs->openings > 0) {
                                        xpt_dev_ccbq_resize(crs->ccb_h.path,
                                                            crs->openings);

                                        if (bootverbose) {
                                                xpt_print(crs->ccb_h.path,
                                                    "tagged openings now %d\n",
                                                    crs->openings);
                                        }
                                }
                        }
                }

                if ((crs->release_flags & RELSIM_RELEASE_AFTER_TIMEOUT) != 0) {

                        if ((dev->flags & CAM_DEV_REL_TIMEOUT_PENDING) != 0) {

                                /*
                                 * Just extend the old timeout and decrement
                                 * the freeze count so that a single timeout
                                 * is sufficient for releasing the queue.
                                 */
                                start_ccb->ccb_h.flags &= ~CAM_DEV_QFREEZE;
                                callout_stop(&dev->callout);
                        } else {

                                start_ccb->ccb_h.flags |= CAM_DEV_QFREEZE;
                        }

                        callout_reset(&dev->callout,
                                      (crs->release_timeout * hz) / 1000, 
                                      xpt_release_devq_timeout, dev);

                        dev->flags |= CAM_DEV_REL_TIMEOUT_PENDING;

                }

                if ((crs->release_flags & RELSIM_RELEASE_AFTER_CMDCMPLT) != 0) {

                        if ((dev->flags & CAM_DEV_REL_ON_COMPLETE) != 0) {
                                /*
                                 * Decrement the freeze count so that a single
                                 * completion is still sufficient to unfreeze
                                 * the queue.
                                 */
                                start_ccb->ccb_h.flags &= ~CAM_DEV_QFREEZE;
                        } else {

                                dev->flags |= CAM_DEV_REL_ON_COMPLETE;
                                start_ccb->ccb_h.flags |= CAM_DEV_QFREEZE;
                        }
                }

                if ((crs->release_flags & RELSIM_RELEASE_AFTER_QEMPTY) != 0) {

                        if ((dev->flags & CAM_DEV_REL_ON_QUEUE_EMPTY) != 0
                         || (dev->ccbq.dev_active == 0)) {

                                start_ccb->ccb_h.flags &= ~CAM_DEV_QFREEZE;
                        } else {

                                dev->flags |= CAM_DEV_REL_ON_QUEUE_EMPTY;
                                start_ccb->ccb_h.flags |= CAM_DEV_QFREEZE;
                        }
                }
                
                if ((start_ccb->ccb_h.flags & CAM_DEV_QFREEZE) == 0) {

                        xpt_release_devq(crs->ccb_h.path, /*count*/1,
                                         /*run_queue*/TRUE);
                }
                start_ccb->crs.qfrozen_cnt = dev->qfrozen_cnt;
                start_ccb->ccb_h.status = CAM_REQ_CMP;
                break;
        }
        case XPT_SCAN_BUS:
                xpt_scan_bus(start_ccb->ccb_h.path->periph, start_ccb);
                break;
        case XPT_SCAN_LUN:
                xpt_scan_lun(start_ccb->ccb_h.path->periph,
                             start_ccb->ccb_h.path, start_ccb->crcn.flags,
                             start_ccb);
                break;
        case XPT_DEBUG: {
#ifdef CAMDEBUG
#ifdef CAM_DEBUG_DELAY
                cam_debug_delay = CAM_DEBUG_DELAY;
#endif
                cam_dflags = start_ccb->cdbg.flags;
                if (cam_dpath != NULL) {
                        xpt_free_path(cam_dpath);
                        cam_dpath = NULL;
                }

                if (cam_dflags != CAM_DEBUG_NONE) {
                        if (xpt_create_path(&cam_dpath, xpt_periph,
                                            start_ccb->ccb_h.path_id,
                                            start_ccb->ccb_h.target_id,
                                            start_ccb->ccb_h.target_lun) !=
                                            CAM_REQ_CMP) {
                                start_ccb->ccb_h.status = CAM_RESRC_UNAVAIL;
                                cam_dflags = CAM_DEBUG_NONE;
                        } else {
                                start_ccb->ccb_h.status = CAM_REQ_CMP;
                                xpt_print(cam_dpath, "debugging flags now %x\n",
                                    cam_dflags);
                        }
                } else {
                        cam_dpath = NULL;
                        start_ccb->ccb_h.status = CAM_REQ_CMP;
                }
#else /* !CAMDEBUG */
                start_ccb->ccb_h.status = CAM_FUNC_NOTAVAIL;
#endif /* CAMDEBUG */
                break;
        }
        case XPT_NOOP:
                if ((start_ccb->ccb_h.flags & CAM_DEV_QFREEZE) != 0)
                        xpt_freeze_devq(start_ccb->ccb_h.path, 1);
                start_ccb->ccb_h.status = CAM_REQ_CMP;
                break;
        default:
        case XPT_SDEV_TYPE:
        case XPT_TERM_IO:
        case XPT_ENG_INQ:
                /* XXX Implement */
                start_ccb->ccb_h.status = CAM_PROVIDE_FAIL;
                break;
        }
}

void
xpt_polled_action(union ccb *start_ccb)
{
        u_int32_t timeout;
        struct    cam_sim *sim;
        struct    cam_devq *devq;
        struct    cam_ed *dev;

        timeout = start_ccb->ccb_h.timeout;
        sim = start_ccb->ccb_h.path->bus->sim;
        devq = sim->devq;
        dev = start_ccb->ccb_h.path->device;

        sim_lock_assert_owned(sim->lock);

        /*
         * Steal an opening so that no other queued requests
         * can get it before us while we simulate interrupts.
         */
        dev->ccbq.devq_openings--;
        dev->ccbq.dev_openings--;

        while(((devq && devq->send_openings <= 0) || dev->ccbq.dev_openings < 0)
           && (--timeout > 0)) {
                DELAY(1000);
                (*(sim->sim_poll))(sim);
                camisr_runqueue(sim);
        }

        dev->ccbq.devq_openings++;
        dev->ccbq.dev_openings++;

        if (timeout != 0) {
                xpt_action(start_ccb);
                while(--timeout > 0) {
                        (*(sim->sim_poll))(sim);
                        camisr_runqueue(sim);
                        if ((start_ccb->ccb_h.status  & CAM_STATUS_MASK)
                            != CAM_REQ_INPROG)
                                break;
                        DELAY(1000);
                }
                if (timeout == 0) {
                        /*
                         * XXX Is it worth adding a sim_timeout entry
                         * point so we can attempt recovery?  If
                         * this is only used for dumps, I don't think
                         * it is.
                         */
                        start_ccb->ccb_h.status = CAM_CMD_TIMEOUT;
                }
        } else {
                start_ccb->ccb_h.status = CAM_RESRC_UNAVAIL;
        }
}

/*
 * Schedule a peripheral driver to receive a ccb when it's
 * target device has space for more transactions.
 */
void
xpt_schedule(struct cam_periph *perph, u_int32_t new_priority)
{
        struct cam_ed *device;
        union ccb *work_ccb;
        int runq;

        sim_lock_assert_owned(perph->sim->lock);

        CAM_DEBUG(perph->path, CAM_DEBUG_TRACE, ("xpt_schedule\n"));
        device = perph->path->device;
        if (periph_is_queued(perph)) {
                /* Simply reorder based on new priority */
                CAM_DEBUG(perph->path, CAM_DEBUG_SUBTRACE,
                          ("   change priority to %d\n", new_priority));
                if (new_priority < perph->pinfo.priority) {
                        camq_change_priority(&device->drvq,
                                             perph->pinfo.index,
                                             new_priority);
                }
                runq = 0;
        } else if (perph->path->bus->sim == &cam_dead_sim) {
                /* The SIM is gone so just call periph_start directly. */
                work_ccb = xpt_get_ccb(perph->path->device);
                if (work_ccb == NULL)
                        return; /* XXX */
                xpt_setup_ccb(&work_ccb->ccb_h, perph->path, new_priority);
                perph->pinfo.priority = new_priority;
                perph->periph_start(perph, work_ccb);
                return;
        } else {
                /* New entry on the queue */
                CAM_DEBUG(perph->path, CAM_DEBUG_SUBTRACE,
                          ("   added periph to queue\n"));
                perph->pinfo.priority = new_priority;
                perph->pinfo.generation = ++device->drvq.generation;
                camq_insert(&device->drvq, &perph->pinfo);
                runq = xpt_schedule_dev_allocq(perph->path->bus, device);
        }
        if (runq != 0) {
                CAM_DEBUG(perph->path, CAM_DEBUG_SUBTRACE,
                          ("   calling xpt_run_devq\n"));
                xpt_run_dev_allocq(perph->path->bus);
        }
}


/*
 * Schedule a device to run on a given queue.
 * If the device was inserted as a new entry on the queue,
 * return 1 meaning the device queue should be run. If we
 * were already queued, implying someone else has already
 * started the queue, return 0 so the caller doesn't attempt
 * to run the queue.
 */
static int
xpt_schedule_dev(struct camq *queue, cam_pinfo *pinfo,
                 u_int32_t new_priority)
{
        int retval;
        u_int32_t old_priority;

        CAM_DEBUG_PRINT(CAM_DEBUG_XPT, ("xpt_schedule_dev\n"));

        old_priority = pinfo->priority;

        /*
         * Are we already queued?
         */
        if (pinfo->index != CAM_UNQUEUED_INDEX) {
                /* Simply reorder based on new priority */
                if (new_priority < old_priority) {
                        camq_change_priority(queue, pinfo->index,
                                             new_priority);
                        CAM_DEBUG_PRINT(CAM_DEBUG_XPT,
                                        ("changed priority to %d\n",
                                         new_priority));
                }
                retval = 0;
        } else {
                /* New entry on the queue */
                if (new_priority < old_priority)
                        pinfo->priority = new_priority;

                CAM_DEBUG_PRINT(CAM_DEBUG_XPT,
                                ("Inserting onto queue\n"));
                pinfo->generation = ++queue->generation;
                camq_insert(queue, pinfo);
                retval = 1;
        }
        return (retval);
}

static void
xpt_run_dev_allocq(struct cam_eb *bus)
{
        struct  cam_devq *devq;

        if ((devq = bus->sim->devq) == NULL) {
                CAM_DEBUG_PRINT(CAM_DEBUG_XPT, ("xpt_run_dev_allocq: NULL devq\n"));
                return;
        }
        CAM_DEBUG_PRINT(CAM_DEBUG_XPT, ("xpt_run_dev_allocq\n"));

        CAM_DEBUG_PRINT(CAM_DEBUG_XPT,
                        ("   qfrozen_cnt == 0x%x, entries == %d, "
                         "openings == %d, active == %d\n",
                         devq->alloc_queue.qfrozen_cnt,
                         devq->alloc_queue.entries,
                         devq->alloc_openings,
                         devq->alloc_active));

        devq->alloc_queue.qfrozen_cnt++;
        while ((devq->alloc_queue.entries > 0)
            && (devq->alloc_openings > 0)
            && (devq->alloc_queue.qfrozen_cnt <= 1)) {
                struct  cam_ed_qinfo *qinfo;
                struct  cam_ed *device;
                union   ccb *work_ccb;
                struct  cam_periph *drv;
                struct  camq *drvq;

                qinfo = (struct cam_ed_qinfo *)camq_remove(&devq->alloc_queue,
                                                           CAMQ_HEAD);
                device = qinfo->device;

                CAM_DEBUG_PRINT(CAM_DEBUG_XPT,
                                ("running device %p\n", device));

                drvq = &device->drvq;

#ifdef CAMDEBUG
                if (drvq->entries <= 0) {
                        panic("xpt_run_dev_allocq: "
                              "Device on queue without any work to do");
                }
#endif
                if ((work_ccb = xpt_get_ccb(device)) != NULL) {
                        devq->alloc_openings--;
                        devq->alloc_active++;
                        drv = (struct cam_periph*)camq_remove(drvq, CAMQ_HEAD);
                        xpt_setup_ccb(&work_ccb->ccb_h, drv->path,
                                      drv->pinfo.priority);
                        CAM_DEBUG_PRINT(CAM_DEBUG_XPT,
                                        ("calling periph start\n"));
                        drv->periph_start(drv, work_ccb);
                } else {
                        /*
                         * Malloc failure in alloc_ccb
                         */
                        /*
                         * XXX add us to a list to be run from free_ccb
                         * if we don't have any ccbs active on this
                         * device queue otherwise we may never get run
                         * again.
                         */
                        break;
                }

                if (drvq->entries > 0) {
                        /* We have more work.  Attempt to reschedule */
                        xpt_schedule_dev_allocq(bus, device);
                }
        }
        devq->alloc_queue.qfrozen_cnt--;
}

static void
xpt_run_dev_sendq(struct cam_eb *bus)
{
        struct  cam_devq *devq;

        if ((devq = bus->sim->devq) == NULL) {
                CAM_DEBUG_PRINT(CAM_DEBUG_XPT, ("xpt_run_dev_sendq: NULL devq\n"));
                return;
        }
        CAM_DEBUG_PRINT(CAM_DEBUG_XPT, ("xpt_run_dev_sendq\n"));

        devq->send_queue.qfrozen_cnt++;
        while ((devq->send_queue.entries > 0)
            && (devq->send_openings > 0)) {
                struct  cam_ed_qinfo *qinfo;
                struct  cam_ed *device;
                union ccb *work_ccb;
                struct  cam_sim *sim;

                if (devq->send_queue.qfrozen_cnt > 1) {
                        break;
                }

                qinfo = (struct cam_ed_qinfo *)camq_remove(&devq->send_queue,
                                                           CAMQ_HEAD);
                device = qinfo->device;

                /*
                 * If the device has been "frozen", don't attempt
                 * to run it.
                 */
                if (device->qfrozen_cnt > 0) {
                        continue;
                }

                CAM_DEBUG_PRINT(CAM_DEBUG_XPT,
                                ("running device %p\n", device));

                work_ccb = cam_ccbq_peek_ccb(&device->ccbq, CAMQ_HEAD);
                if (work_ccb == NULL) {
                        kprintf("device on run queue with no ccbs???\n");
                        continue;
                }

                if ((work_ccb->ccb_h.flags & CAM_HIGH_POWER) != 0) {

                        lockmgr(&xsoftc.xpt_lock, LK_EXCLUSIVE);
                        if (xsoftc.num_highpower <= 0) {
                                /*
                                 * We got a high power command, but we
                                 * don't have any available slots.  Freeze
                                 * the device queue until we have a slot
                                 * available.
                                 */
                                device->qfrozen_cnt++;
                                STAILQ_INSERT_TAIL(&xsoftc.highpowerq,
                                                   &work_ccb->ccb_h,
                                                   xpt_links.stqe);

                                lockmgr(&xsoftc.xpt_lock, LK_RELEASE);
                                continue;
                        } else {
                                /*
                                 * Consume a high power slot while
                                 * this ccb runs.
                                 */
                                xsoftc.num_highpower--;
                        }
                        lockmgr(&xsoftc.xpt_lock, LK_RELEASE);
                }
                devq->active_dev = device;
                cam_ccbq_remove_ccb(&device->ccbq, work_ccb);

                cam_ccbq_send_ccb(&device->ccbq, work_ccb);

                devq->send_openings--;
                devq->send_active++;

                if (device->ccbq.queue.entries > 0)
                        xpt_schedule_dev_sendq(bus, device);

                if (work_ccb && (work_ccb->ccb_h.flags & CAM_DEV_QFREEZE) != 0){
                        /*
                         * The client wants to freeze the queue
                         * after this CCB is sent.
                         */
                        device->qfrozen_cnt++;
                }

                /* In Target mode, the peripheral driver knows best... */
                if (work_ccb->ccb_h.func_code == XPT_SCSI_IO) {
                        if ((device->inq_flags & SID_CmdQue) != 0
                         && work_ccb->csio.tag_action != CAM_TAG_ACTION_NONE)
                                work_ccb->ccb_h.flags |= CAM_TAG_ACTION_VALID;
                        else
                                /*
                                 * Clear this in case of a retried CCB that
                                 * failed due to a rejected tag.
                                 */
                                work_ccb->ccb_h.flags &= ~CAM_TAG_ACTION_VALID;
                }

                /*
                 * Device queues can be shared among multiple sim instances
                 * that reside on different busses.  Use the SIM in the queue
                 * CCB's path, rather than the one in the bus that was passed
                 * into this function.
                 */
                sim = work_ccb->ccb_h.path->bus->sim;
                (*(sim->sim_action))(sim, work_ccb);

                devq->active_dev = NULL;
        }
        devq->send_queue.qfrozen_cnt--;
}

/*
 * This function merges stuff from the slave ccb into the master ccb, while
 * keeping important fields in the master ccb constant.
 */
void
xpt_merge_ccb(union ccb *master_ccb, union ccb *slave_ccb)
{
        /*
         * Pull fields that are valid for peripheral drivers to set
         * into the master CCB along with the CCB "payload".
         */
        master_ccb->ccb_h.retry_count = slave_ccb->ccb_h.retry_count;
        master_ccb->ccb_h.func_code = slave_ccb->ccb_h.func_code;
        master_ccb->ccb_h.timeout = slave_ccb->ccb_h.timeout;
        master_ccb->ccb_h.flags = slave_ccb->ccb_h.flags;
        bcopy(&(&slave_ccb->ccb_h)[1], &(&master_ccb->ccb_h)[1],
              sizeof(union ccb) - sizeof(struct ccb_hdr));
}

void
xpt_setup_ccb(struct ccb_hdr *ccb_h, struct cam_path *path, u_int32_t priority)
{
        CAM_DEBUG(path, CAM_DEBUG_TRACE, ("xpt_setup_ccb\n"));
        callout_init(ccb_h->timeout_ch);
        ccb_h->pinfo.priority = priority;
        ccb_h->path = path;
        ccb_h->path_id = path->bus->path_id;
        if (path->target)
                ccb_h->target_id = path->target->target_id;
        else
                ccb_h->target_id = CAM_TARGET_WILDCARD;
        if (path->device) {
                ccb_h->target_lun = path->device->lun_id;
                ccb_h->pinfo.generation = ++path->device->ccbq.queue.generation;
        } else {
                ccb_h->target_lun = CAM_TARGET_WILDCARD;
        }
        ccb_h->pinfo.index = CAM_UNQUEUED_INDEX;
        ccb_h->flags = 0;
}

/* Path manipulation functions */
cam_status
xpt_create_path(struct cam_path **new_path_ptr, struct cam_periph *perph,
                path_id_t path_id, target_id_t target_id, lun_id_t lun_id)
{
        struct     cam_path *path;
        cam_status status;

        path = kmalloc(sizeof(*path), M_CAMXPT, M_INTWAIT);
        status = xpt_compile_path(path, perph, path_id, target_id, lun_id);
        if (status != CAM_REQ_CMP) {
                kfree(path, M_CAMXPT);
                path = NULL;
        }
        *new_path_ptr = path;
        return (status);
}

cam_status
xpt_create_path_unlocked(struct cam_path **new_path_ptr,
                         struct cam_periph *periph, path_id_t path_id,
                         target_id_t target_id, lun_id_t lun_id)
{
        struct     cam_path *path;
        struct     cam_eb *bus = NULL;
        cam_status status;
        int        need_unlock = 0;

        path = (struct cam_path *)kmalloc(sizeof(*path), M_CAMXPT, M_WAITOK);

        if (path_id != CAM_BUS_WILDCARD) {
                bus = xpt_find_bus(path_id);
                if (bus != NULL) {
                        need_unlock = 1;
                        CAM_SIM_LOCK(bus->sim);
                }
        }
        status = xpt_compile_path(path, periph, path_id, target_id, lun_id);
        if (need_unlock)
                CAM_SIM_UNLOCK(bus->sim);
        if (status != CAM_REQ_CMP) {
                kfree(path, M_CAMXPT);
                path = NULL;
        }
        *new_path_ptr = path;
        return (status);
}

static cam_status
xpt_compile_path(struct cam_path *new_path, struct cam_periph *perph,
                 path_id_t path_id, target_id_t target_id, lun_id_t lun_id)
{
        struct       cam_eb *bus;
        struct       cam_et *target;
        struct       cam_ed *device;
        cam_status   status;

        status = CAM_REQ_CMP;   /* Completed without error */
        target = NULL;          /* Wildcarded */
        device = NULL;          /* Wildcarded */

        /*
         * We will potentially modify the EDT, so block interrupts
         * that may attempt to create cam paths.
         */
        bus = xpt_find_bus(path_id);
        if (bus == NULL) {
                status = CAM_PATH_INVALID;
        } else {
                target = xpt_find_target(bus, target_id);
                if (target == NULL) {
                        /* Create one */
                        struct cam_et *new_target;

                        new_target = xpt_alloc_target(bus, target_id);
                        if (new_target == NULL) {
                                status = CAM_RESRC_UNAVAIL;
                        } else {
                                target = new_target;
                        }
                }
                if (target != NULL) {
                        device = xpt_find_device(target, lun_id);
                        if (device == NULL) {
                                /* Create one */
                                struct cam_ed *new_device;

                                new_device = xpt_alloc_device(bus,
                                                              target,
                                                              lun_id);
                                if (new_device == NULL) {
                                        status = CAM_RESRC_UNAVAIL;
                                } else {
                                        device = new_device;
                                }
                        }
                }
        }

        /*
         * Only touch the user's data if we are successful.
         */
        if (status == CAM_REQ_CMP) {
                new_path->periph = perph;
                new_path->bus = bus;
                new_path->target = target;
                new_path->device = device;
                CAM_DEBUG(new_path, CAM_DEBUG_TRACE, ("xpt_compile_path\n"));
        } else {
                if (device != NULL)
                        xpt_release_device(bus, target, device);
                if (target != NULL)
                        xpt_release_target(bus, target);
                if (bus != NULL)
                        xpt_release_bus(bus);
        }
        return (status);
}

static void
xpt_release_path(struct cam_path *path)
{
        CAM_DEBUG(path, CAM_DEBUG_TRACE, ("xpt_release_path\n"));
        if (path->device != NULL) {
                xpt_release_device(path->bus, path->target, path->device);
                path->device = NULL;
        }
        if (path->target != NULL) {
                xpt_release_target(path->bus, path->target);
                path->target = NULL;
        }
        if (path->bus != NULL) {
                xpt_release_bus(path->bus);
                path->bus = NULL;
        }
}

void
xpt_free_path(struct cam_path *path)
{
        CAM_DEBUG(path, CAM_DEBUG_TRACE, ("xpt_free_path\n"));
        xpt_release_path(path);
        kfree(path, M_CAMXPT);
}


/*
 * Return -1 for failure, 0 for exact match, 1 for match with wildcards
 * in path1, 2 for match with wildcards in path2.
 */
int
xpt_path_comp(struct cam_path *path1, struct cam_path *path2)
{
        int retval = 0;

        if (path1->bus != path2->bus) {
                if (path1->bus->path_id == CAM_BUS_WILDCARD)
                        retval = 1;
                else if (path2->bus->path_id == CAM_BUS_WILDCARD)
                        retval = 2;
                else
                        return (-1);
        }
        if (path1->target != path2->target) {
                if (path1->target->target_id == CAM_TARGET_WILDCARD) {
                        if (retval == 0)
                                retval = 1;
                } else if (path2->target->target_id == CAM_TARGET_WILDCARD)
                        retval = 2;
                else
                        return (-1);
        }
        if (path1->device != path2->device) {
                if (path1->device->lun_id == CAM_LUN_WILDCARD) {
                        if (retval == 0)
                                retval = 1;
                } else if (path2->device->lun_id == CAM_LUN_WILDCARD)
                        retval = 2;
                else
                        return (-1);
        }
        return (retval);
}

void
xpt_print_path(struct cam_path *path)
{

        if (path == NULL)
                kprintf("(nopath): ");
        else {
                if (path->periph != NULL)
                        kprintf("(%s%d:", path->periph->periph_name,
                               path->periph->unit_number);
                else
                        kprintf("(noperiph:");

                if (path->bus != NULL)
                        kprintf("%s%d:%d:", path->bus->sim->sim_name,
                               path->bus->sim->unit_number,
                               path->bus->sim->bus_id);
                else
                        kprintf("nobus:");

                if (path->target != NULL)
                        kprintf("%d:", path->target->target_id);
                else
                        kprintf("X:");

                if (path->device != NULL)
                        kprintf("%d): ", path->device->lun_id);
                else
                        kprintf("X): ");
        }
}

void
xpt_print(struct cam_path *path, const char *fmt, ...)
{
        __va_list ap;
        xpt_print_path(path);
        __va_start(ap, fmt);
        kvprintf(fmt, ap);
        __va_end(ap);
}

int
xpt_path_string(struct cam_path *path, char *str, size_t str_len)
{
        struct sbuf sb;

        sim_lock_assert_owned(path->bus->sim->lock);

        sbuf_new(&sb, str, str_len, 0);

        if (path == NULL)
                sbuf_printf(&sb, "(nopath): ");
        else {
                if (path->periph != NULL)
                        sbuf_printf(&sb, "(%s%d:", path->periph->periph_name,
                                    path->periph->unit_number);
                else
                        sbuf_printf(&sb, "(noperiph:");

                if (path->bus != NULL)
                        sbuf_printf(&sb, "%s%d:%d:", path->bus->sim->sim_name,
                                    path->bus->sim->unit_number,
                                    path->bus->sim->bus_id);
                else
                        sbuf_printf(&sb, "nobus:");

                if (path->target != NULL)
                        sbuf_printf(&sb, "%d:", path->target->target_id);
                else
                        sbuf_printf(&sb, "X:");

                if (path->device != NULL)
                        sbuf_printf(&sb, "%d): ", path->device->lun_id);
                else
                        sbuf_printf(&sb, "X): ");
        }
        sbuf_finish(&sb);

        return(sbuf_len(&sb));
}

path_id_t
xpt_path_path_id(struct cam_path *path)
{
        sim_lock_assert_owned(path->bus->sim->lock);

        return(path->bus->path_id);
}

target_id_t
xpt_path_target_id(struct cam_path *path)
{
        sim_lock_assert_owned(path->bus->sim->lock);

        if (path->target != NULL)
                return (path->target->target_id);
        else
                return (CAM_TARGET_WILDCARD);
}

lun_id_t
xpt_path_lun_id(struct cam_path *path)
{
        sim_lock_assert_owned(path->bus->sim->lock);

        if (path->device != NULL)
                return (path->device->lun_id);
        else
                return (CAM_LUN_WILDCARD);
}

struct cam_sim *
xpt_path_sim(struct cam_path *path)
{
        return (path->bus->sim);
}

struct cam_periph*
xpt_path_periph(struct cam_path *path)
{
        sim_lock_assert_owned(path->bus->sim->lock);

        return (path->periph);
}

char *
xpt_path_serialno(struct cam_path *path)
{
        return (path->device->serial_num);
}

/*
 * Release a CAM control block for the caller.  Remit the cost of the structure
 * to the device referenced by the path.  If the this device had no 'credits'
 * and peripheral drivers have registered async callbacks for this notification
 * call them now.
 */
void
xpt_release_ccb(union ccb *free_ccb)
{
        struct   cam_path *path;
        struct   cam_ed *device;
        struct   cam_eb *bus;
        struct   cam_sim *sim;

        CAM_DEBUG_PRINT(CAM_DEBUG_XPT, ("xpt_release_ccb\n"));
        path = free_ccb->ccb_h.path;
        device = path->device;
        bus = path->bus;
        sim = bus->sim;

        sim_lock_assert_owned(sim->lock);

        cam_ccbq_release_opening(&device->ccbq);
        if (sim->ccb_count > sim->max_ccbs) {
                xpt_free_ccb(&free_ccb->ccb_h);
                sim->ccb_count--;
        } else if (sim == &cam_dead_sim) {
                xpt_free_ccb(&free_ccb->ccb_h);
        } else  {
                SLIST_INSERT_HEAD(&sim->ccb_freeq, &free_ccb->ccb_h,
                                  xpt_links.sle);
        }
        if (sim->devq == NULL) {
                return;
        }
        sim->devq->alloc_openings++;
        sim->devq->alloc_active--;
        /* XXX Turn this into an inline function - xpt_run_device?? */
        if ((device_is_alloc_queued(device) == 0)
         && (device->drvq.entries > 0)) {
                xpt_schedule_dev_allocq(bus, device);
        }
        if (dev_allocq_is_runnable(sim->devq))
                xpt_run_dev_allocq(bus);
}

/* Functions accessed by SIM drivers */

/*
 * A sim structure, listing the SIM entry points and instance
 * identification info is passed to xpt_bus_register to hook the SIM
 * into the CAM framework.  xpt_bus_register creates a cam_eb entry
 * for this new bus and places it in the array of busses and assigns
 * it a path_id.  The path_id may be influenced by "hard wiring"
 * information specified by the user.  Once interrupt services are
 * availible, the bus will be probed.
 */
int32_t
xpt_bus_register(struct cam_sim *sim, u_int32_t bus)
{
        struct cam_eb *new_bus;
        struct cam_eb *old_bus;
        struct ccb_pathinq *cpi;

        sim_lock_assert_owned(sim->lock);

        sim->bus_id = bus;
        new_bus = kmalloc(sizeof(*new_bus), M_CAMXPT, M_INTWAIT);

        /*
         * Must hold topo lock across xptpathid() through installation of
         * new_bus to avoid duplication due to SMP races.
         */
        lockmgr(&xsoftc.xpt_topo_lock, LK_EXCLUSIVE);
        if (strcmp(sim->sim_name, "xpt") != 0) {
                sim->path_id =
                    xptpathid(sim->sim_name, sim->unit_number, sim->bus_id);
        }

        TAILQ_INIT(&new_bus->et_entries);
        new_bus->path_id = sim->path_id;
        new_bus->sim = sim;
        atomic_add_int(&sim->refcount, 1);
        timevalclear(&new_bus->last_reset);
        new_bus->flags = 0;
        new_bus->refcount = 1;  /* Held until a bus_deregister event */
        new_bus->generation = 0;
        new_bus->counted_to_config = 0;
        old_bus = TAILQ_FIRST(&xsoftc.xpt_busses);
        while (old_bus != NULL && old_bus->path_id < new_bus->path_id)
                old_bus = TAILQ_NEXT(old_bus, links);
        if (old_bus != NULL)
                TAILQ_INSERT_BEFORE(old_bus, new_bus, links);
        else
                TAILQ_INSERT_TAIL(&xsoftc.xpt_busses, new_bus, links);
        xsoftc.bus_generation++;
        lockmgr(&xsoftc.xpt_topo_lock, LK_RELEASE);

        /* Notify interested parties */
        if (sim->path_id != CAM_XPT_PATH_ID) {
                struct cam_path path;

                cpi = &xpt_alloc_ccb()->cpi;
                xpt_compile_path(&path, /*periph*/NULL, sim->path_id,
                                 CAM_TARGET_WILDCARD, CAM_LUN_WILDCARD);
                xpt_setup_ccb(&cpi->ccb_h, &path, /*priority*/1);
                cpi->ccb_h.func_code = XPT_PATH_INQ;
                xpt_action((union ccb *)cpi);
                xpt_async(AC_PATH_REGISTERED, &path, cpi);
                xpt_release_path(&path);
                xpt_free_ccb(&cpi->ccb_h);
        }
        return (CAM_SUCCESS);
}

/*
 * Deregister a bus.  We must clean out all transactions pending on the bus.
 * This routine is typically called prior to cam_sim_free() (e.g. see
 * dev/usbmisc/umass/umass.c)
 */
int32_t
xpt_bus_deregister(path_id_t pathid)
{
        struct cam_path bus_path;
        struct cam_et *target;
        struct cam_ed *device;
        struct cam_ed_qinfo *qinfo;
        struct cam_devq *devq;
        struct cam_periph *periph;
        struct cam_sim *ccbsim;
        union ccb *work_ccb;
        cam_status status;
        int retries = 0;

        status = xpt_compile_path(&bus_path, NULL, pathid,
                                  CAM_TARGET_WILDCARD, CAM_LUN_WILDCARD);
        if (status != CAM_REQ_CMP)
                return (status);

        /*
         * This should clear out all pending requests and timeouts, but
         * the ccb's may be queued to a software interrupt.
         *
         * XXX AC_LOST_DEVICE does not precisely abort the pending requests,
         * and it really ought to.
         */
        xpt_async(AC_LOST_DEVICE, &bus_path, NULL);
        xpt_async(AC_PATH_DEREGISTERED, &bus_path, NULL);

        /*
         * Mark the SIM as having been deregistered.  This prevents
         * certain operations from re-queueing to it, stops new devices
         * from being added, etc.
         */
        devq = bus_path.bus->sim->devq;
        ccbsim = bus_path.bus->sim;
        ccbsim->flags |= CAM_SIM_DEREGISTERED;

again:
        /*
         * Execute any pending operations now. 
         */
        while ((qinfo = (struct cam_ed_qinfo *)camq_remove(&devq->send_queue,
            CAMQ_HEAD)) != NULL ||
            (qinfo = (struct cam_ed_qinfo *)camq_remove(&devq->alloc_queue,
            CAMQ_HEAD)) != NULL) {
                do {
                        device = qinfo->device;
                        work_ccb = cam_ccbq_peek_ccb(&device->ccbq, CAMQ_HEAD);
                        if (work_ccb != NULL) {
                                devq->active_dev = device;
                                cam_ccbq_remove_ccb(&device->ccbq, work_ccb);
                                cam_ccbq_send_ccb(&device->ccbq, work_ccb);
                                (*(ccbsim->sim_action))(ccbsim, work_ccb);
                        }

                        periph = (struct cam_periph *)camq_remove(&device->drvq,
                            CAMQ_HEAD);
                        if (periph != NULL)
                                xpt_schedule(periph, periph->pinfo.priority);
                } while (work_ccb != NULL || periph != NULL);
        }

        /*
         * Make sure all completed CCBs are processed. 
         */
        while (!TAILQ_EMPTY(&ccbsim->sim_doneq)) {
                camisr_runqueue(ccbsim);
        }

        /*
         * Check for requeues, reissues asyncs if necessary
         */
        if (CAMQ_GET_HEAD(&devq->send_queue))
                kprintf("camq: devq send_queue still in use (%d entries)\n",
                        devq->send_queue.entries);
        if (CAMQ_GET_HEAD(&devq->alloc_queue))
                kprintf("camq: devq alloc_queue still in use (%d entries)\n",
                        devq->alloc_queue.entries);
        if (CAMQ_GET_HEAD(&devq->send_queue) || 
            CAMQ_GET_HEAD(&devq->alloc_queue)) {
                if (++retries < 5) {
                        xpt_async(AC_LOST_DEVICE, &bus_path, NULL);
                        xpt_async(AC_PATH_DEREGISTERED, &bus_path, NULL);
                        goto again;
                }
        }

        /*
         * Retarget the bus and all cached sim pointers to dead_sim.
         *
         * Various CAM subsystems may be holding on to targets, devices,
         * and/or peripherals and may attempt to use the sim pointer cached
         * in some of these structures during close.
         */
        lockmgr(&xsoftc.xpt_topo_lock, LK_EXCLUSIVE);
        bus_path.bus->sim = &cam_dead_sim;
        TAILQ_FOREACH(target, &bus_path.bus->et_entries, links) {
                TAILQ_FOREACH(device, &target->ed_entries, links) {
                        device->sim = &cam_dead_sim;
                        SLIST_FOREACH(periph, &device->periphs, periph_links) {
                                periph->sim = &cam_dead_sim;
                        }
                }
        }
        lockmgr(&xsoftc.xpt_topo_lock, LK_RELEASE);

        /*
         * Repeat the async's for the benefit of any new devices, such as
         * might be created from completed probes.  Any new device
         * ops will run on dead_sim.
         *
         * XXX There are probably races :-(
         */
        CAM_SIM_LOCK(&cam_dead_sim);
        xpt_async(AC_LOST_DEVICE, &bus_path, NULL);
        xpt_async(AC_PATH_DEREGISTERED, &bus_path, NULL);
        CAM_SIM_UNLOCK(&cam_dead_sim);

        /* Release the reference count held while registered. */
        xpt_release_bus(bus_path.bus);
        xpt_release_path(&bus_path);

        /* Release the ref we got when the bus was registered */
        cam_sim_release(ccbsim, 0);

        return (CAM_REQ_CMP);
}

/*
 * Must be called with xpt_topo_lock held.
 */
static path_id_t
xptnextfreepathid(void)
{
        struct cam_eb *bus;
        path_id_t pathid;
        const char *strval;

        pathid = 0;
        bus = TAILQ_FIRST(&xsoftc.xpt_busses);
retry:
        /* Find an unoccupied pathid */
        while (bus != NULL && bus->path_id <= pathid) {
                if (bus->path_id == pathid)
                        pathid++;
                bus = TAILQ_NEXT(bus, links);
        }

        /*
         * Ensure that this pathid is not reserved for
         * a bus that may be registered in the future.
         */
        if (resource_string_value("scbus", pathid, "at", &strval) == 0) {
                ++pathid;
                /* Start the search over */
                goto retry;
        }
        return (pathid);
}

/*
 * Must be called with xpt_topo_lock held.
 */
static path_id_t
xptpathid(const char *sim_name, int sim_unit, int sim_bus)
{
        path_id_t pathid;
        int i, dunit, val;
        char buf[32];

        pathid = CAM_XPT_PATH_ID;
        ksnprintf(buf, sizeof(buf), "%s%d", sim_name, sim_unit);
        i = -1;
        while ((i = resource_query_string(i, "at", buf)) != -1) {
                if (strcmp(resource_query_name(i), "scbus")) {
                        /* Avoid a bit of foot shooting. */
                        continue;
                }
                dunit = resource_query_unit(i);
                if (dunit < 0)          /* unwired?! */
                        continue;
                if (resource_int_value("scbus", dunit, "bus", &val) == 0) {
                        if (sim_bus == val) {
                                pathid = dunit;
                                break;
                        }
                } else if (sim_bus == 0) {
                        /* Unspecified matches bus 0 */
                        pathid = dunit;
                        break;
                } else {
                        kprintf("Ambiguous scbus configuration for %s%d "
                               "bus %d, cannot wire down.  The kernel "
                               "config entry for scbus%d should "
                               "specify a controller bus.\n"
                               "Scbus will be assigned dynamically.\n",
                               sim_name, sim_unit, sim_bus, dunit);
                        break;
                }
        }

        if (pathid == CAM_XPT_PATH_ID)
                pathid = xptnextfreepathid();
        return (pathid);
}

void
xpt_async(u_int32_t async_code, struct cam_path *path, void *async_arg)
{
        struct cam_eb *bus;
        struct cam_et *target, *next_target;
        struct cam_ed *device, *next_device;

        sim_lock_assert_owned(path->bus->sim->lock);

        CAM_DEBUG(path, CAM_DEBUG_TRACE, ("xpt_async\n"));

        /*
         * Most async events come from a CAM interrupt context.  In
         * a few cases, the error recovery code at the peripheral layer,
         * which may run from our SWI or a process context, may signal
         * deferred events with a call to xpt_async.
         */

        bus = path->bus;

        if (async_code == AC_BUS_RESET) {
                /* Update our notion of when the last reset occurred */
                microuptime(&bus->last_reset);
        }

        for (target = TAILQ_FIRST(&bus->et_entries);
             target != NULL;
             target = next_target) {

                next_target = TAILQ_NEXT(target, links);

                if (path->target != target
                 && path->target->target_id != CAM_TARGET_WILDCARD
                 && target->target_id != CAM_TARGET_WILDCARD)
                        continue;

                if (async_code == AC_SENT_BDR) {
                        /* Update our notion of when the last reset occurred */
                        microuptime(&path->target->last_reset);
                }

                for (device = TAILQ_FIRST(&target->ed_entries);
                     device != NULL;
                     device = next_device) {

                        next_device = TAILQ_NEXT(device, links);

                        if (path->device != device
                         && path->device->lun_id != CAM_LUN_WILDCARD
                         && device->lun_id != CAM_LUN_WILDCARD)
                                continue;

                        xpt_dev_async(async_code, bus, target,
                                      device, async_arg);

                        xpt_async_bcast(&device->asyncs, async_code,
                                        path, async_arg);
                }
        }

        /*
         * If this wasn't a fully wildcarded async, tell all
         * clients that want all async events.
         */
        if (bus != xpt_periph->path->bus)
                xpt_async_bcast(&xpt_periph->path->device->asyncs, async_code,
                                path, async_arg);
}

static void
xpt_async_bcast(struct async_list *async_head,
                u_int32_t async_code,
                struct cam_path *path, void *async_arg)
{
        struct async_node *cur_entry;

        cur_entry = SLIST_FIRST(async_head);
        while (cur_entry != NULL) {
                struct async_node *next_entry;
                /*
                 * Grab the next list entry before we call the current
                 * entry's callback.  This is because the callback function
                 * can delete its async callback entry.
                 */
                next_entry = SLIST_NEXT(cur_entry, links);
                if ((cur_entry->event_enable & async_code) != 0)
                        cur_entry->callback(cur_entry->callback_arg,
                                            async_code, path,
                                            async_arg);
                cur_entry = next_entry;
        }
}

/*
 * Handle any per-device event notifications that require action by the XPT.
 */
static void
xpt_dev_async(u_int32_t async_code, struct cam_eb *bus, struct cam_et *target,
              struct cam_ed *device, void *async_arg)
{
        cam_status status;
        struct cam_path newpath;

        /*
         * We only need to handle events for real devices.
         */
        if (target->target_id == CAM_TARGET_WILDCARD
         || device->lun_id == CAM_LUN_WILDCARD)
                return;

        /*
         * We need our own path with wildcards expanded to
         * handle certain types of events.
         */
        if ((async_code == AC_SENT_BDR)
         || (async_code == AC_BUS_RESET)
         || (async_code == AC_INQ_CHANGED))
                status = xpt_compile_path(&newpath, NULL,
                                          bus->path_id,
                                          target->target_id,
                                          device->lun_id);
        else
                status = CAM_REQ_CMP_ERR;

        if (status == CAM_REQ_CMP) {

                /*
                 * Allow transfer negotiation to occur in a
                 * tag free environment.
                 */
                if (async_code == AC_SENT_BDR
                 || async_code == AC_BUS_RESET)
                        xpt_toggle_tags(&newpath);

                if (async_code == AC_INQ_CHANGED) {
                        /*
                         * We've sent a start unit command, or
                         * something similar to a device that
                         * may have caused its inquiry data to
                         * change. So we re-scan the device to
                         * refresh the inquiry data for it.
                         */
                        xpt_scan_lun(newpath.periph, &newpath,
                                     CAM_EXPECT_INQ_CHANGE, NULL);
                }
                xpt_release_path(&newpath);
        } else if (async_code == AC_LOST_DEVICE) {
                /*
                 * When we lose a device the device may be about to detach
                 * the sim, we have to clear out all pending timeouts and
                 * requests before that happens.
                 *
                 * This typically happens most often with USB/UMASS devices.
                 *
                 * XXX it would be nice if we could abort the requests
                 * pertaining to the device.
                 */
                xpt_release_devq_device(device, /*count*/1, /*run_queue*/TRUE);
                if ((device->flags & CAM_DEV_UNCONFIGURED) == 0) {
                        device->flags |= CAM_DEV_UNCONFIGURED;
                        xpt_release_device(bus, target, device);
                }
        } else if (async_code == AC_TRANSFER_NEG) {
                struct ccb_trans_settings *settings;

                settings = (struct ccb_trans_settings *)async_arg;
                xpt_set_transfer_settings(settings, device,
                                          /*async_update*/TRUE);
        }
}

u_int32_t
xpt_freeze_devq(struct cam_path *path, u_int count)
{
        struct ccb_hdr *ccbh;

        sim_lock_assert_owned(path->bus->sim->lock);

        path->device->qfrozen_cnt += count;

        /*
         * Mark the last CCB in the queue as needing
         * to be requeued if the driver hasn't
         * changed it's state yet.  This fixes a race
         * where a ccb is just about to be queued to
         * a controller driver when it's interrupt routine
         * freezes the queue.  To completly close the
         * hole, controller drives must check to see
         * if a ccb's status is still CAM_REQ_INPROG
         * just before they queue
         * the CCB.  See ahc_action/ahc_freeze_devq for
         * an example.
         */
        ccbh = TAILQ_LAST(&path->device->ccbq.active_ccbs, ccb_hdr_tailq);
        if (ccbh && ccbh->status == CAM_REQ_INPROG)
                ccbh->status = CAM_REQUEUE_REQ;
        return (path->device->qfrozen_cnt);
}

u_int32_t
xpt_freeze_simq(struct cam_sim *sim, u_int count)
{
        sim_lock_assert_owned(sim->lock);

        if (sim->devq == NULL)
                return(count);
        sim->devq->send_queue.qfrozen_cnt += count;
        if (sim->devq->active_dev != NULL) {
                struct ccb_hdr *ccbh;

                ccbh = TAILQ_LAST(&sim->devq->active_dev->ccbq.active_ccbs,
                                  ccb_hdr_tailq);
                if (ccbh && ccbh->status == CAM_REQ_INPROG)
                        ccbh->status = CAM_REQUEUE_REQ;
        }
        return (sim->devq->send_queue.qfrozen_cnt);
}

/*
 * Release the device queue after a timeout has expired, typically used to
 * introduce a delay before retrying after an I/O error or other problem.
 */
static void
xpt_release_devq_timeout(void *arg)
{
        struct cam_ed *device;

        device = (struct cam_ed *)arg;
        CAM_SIM_LOCK(device->sim);
        xpt_release_devq_device(device, /*count*/1, /*run_queue*/TRUE);
        CAM_SIM_UNLOCK(device->sim);
}

void
xpt_release_devq(struct cam_path *path, u_int count, int run_queue)
{
        sim_lock_assert_owned(path->bus->sim->lock);

        xpt_release_devq_device(path->device, count, run_queue);
}

static void
xpt_release_devq_device(struct cam_ed *dev, u_int count, int run_queue)
{
        int     rundevq;

        rundevq = 0;

        if (dev->qfrozen_cnt > 0) {

                count = (count > dev->qfrozen_cnt) ? dev->qfrozen_cnt : count;
                dev->qfrozen_cnt -= count;
                if (dev->qfrozen_cnt == 0) {

                        /*
                         * No longer need to wait for a successful
                         * command completion.
                         */
                        dev->flags &= ~CAM_DEV_REL_ON_COMPLETE;

                        /*
                         * Remove any timeouts that might be scheduled
                         * to release this queue.
                         */
                        if ((dev->flags & CAM_DEV_REL_TIMEOUT_PENDING) != 0) {
                                callout_stop(&dev->callout);
                                dev->flags &= ~CAM_DEV_REL_TIMEOUT_PENDING;
                        }

                        /*
                         * Now that we are unfrozen schedule the
                         * device so any pending transactions are
                         * run.
                         */
                        if ((dev->ccbq.queue.entries > 0)
                         && (xpt_schedule_dev_sendq(dev->target->bus, dev))
                         && (run_queue != 0)) {
                                rundevq = 1;
                        }
                }
        }
        if (rundevq != 0)
                xpt_run_dev_sendq(dev->target->bus);
}

void
xpt_release_simq(struct cam_sim *sim, int run_queue)
{
        struct  camq *sendq;

        sim_lock_assert_owned(sim->lock);

        if (sim->devq == NULL)
                return;

        sendq = &(sim->devq->send_queue);
        if (sendq->qfrozen_cnt > 0) {
                sendq->qfrozen_cnt--;
                if (sendq->qfrozen_cnt == 0) {
                        struct cam_eb *bus;

                        /*
                         * If there is a timeout scheduled to release this
                         * sim queue, remove it.  The queue frozen count is
                         * already at 0.
                         */
                        if ((sim->flags & CAM_SIM_REL_TIMEOUT_PENDING) != 0){
                                callout_stop(&sim->callout);
                                sim->flags &= ~CAM_SIM_REL_TIMEOUT_PENDING;
                        }
                        bus = xpt_find_bus(sim->path_id);

                        if (run_queue) {
                                /*
                                 * Now that we are unfrozen run the send queue.
                                 */
                                xpt_run_dev_sendq(bus);
                        }
                        xpt_release_bus(bus);
                }
        }
}

void
xpt_done(union ccb *done_ccb)
{
        struct cam_sim *sim;

        CAM_DEBUG(done_ccb->ccb_h.path, CAM_DEBUG_TRACE, ("xpt_done\n"));
        if ((done_ccb->ccb_h.func_code & XPT_FC_QUEUED) != 0) {
                /*
                 * Queue up the request for handling by our SWI handler
                 * any of the "non-immediate" type of ccbs.
                 */
                sim = done_ccb->ccb_h.path->bus->sim;
                switch (done_ccb->ccb_h.path->periph->type) {
                case CAM_PERIPH_BIO:
                        spin_lock(&sim->sim_spin);
                        TAILQ_INSERT_TAIL(&sim->sim_doneq, &done_ccb->ccb_h,
                                          sim_links.tqe);
                        done_ccb->ccb_h.pinfo.index = CAM_DONEQ_INDEX;
                        spin_unlock(&sim->sim_spin);
                        if ((sim->flags & CAM_SIM_ON_DONEQ) == 0) {
                                spin_lock(&cam_simq_spin);
                                if ((sim->flags & CAM_SIM_ON_DONEQ) == 0) {
                                        TAILQ_INSERT_TAIL(&cam_simq, sim,
                                                          links);
                                        sim->flags |= CAM_SIM_ON_DONEQ;
                                }
                                spin_unlock(&cam_simq_spin);
                        }
                        if ((done_ccb->ccb_h.flags & CAM_POLLED) == 0)
                                setsoftcambio();
                        break;
                default:
                        panic("unknown periph type %d",
                                done_ccb->ccb_h.path->periph->type);
                }
        }
}

union ccb *
xpt_alloc_ccb(void)
{
        union ccb *new_ccb;

        new_ccb = kmalloc(sizeof(*new_ccb), M_CAMXPT, M_INTWAIT | M_ZERO);
        new_ccb->ccb_h.timeout_ch = kmalloc(sizeof(struct callout), M_CAMXPT,
                                            M_INTWAIT | M_ZERO);

        return (new_ccb);
}

void
xpt_free_ccb(struct ccb_hdr *free_ccb)
{
        KKASSERT(free_ccb->timeout_ch != NULL);
        kfree(free_ccb->timeout_ch, M_CAMXPT);
        free_ccb->timeout_ch = NULL;
        kfree(free_ccb, M_CAMXPT);
}

/* Private XPT functions */

/*
 * Get a CAM control block for the caller. Charge the structure to the device
 * referenced by the path.  If the this device has no 'credits' then the
 * device already has the maximum number of outstanding operations under way
 * and we return NULL. If we don't have sufficient resources to allocate more
 * ccbs, we also return NULL.
 */
static union ccb *
xpt_get_ccb(struct cam_ed *device)
{
        union ccb *new_ccb;
        struct cam_sim *sim;

        sim = device->sim;
        if ((new_ccb = (union ccb *)SLIST_FIRST(&sim->ccb_freeq)) == NULL) {
                new_ccb = xpt_alloc_ccb();
                if ((sim->flags & CAM_SIM_MPSAFE) == 0)
                        callout_init(new_ccb->ccb_h.timeout_ch);
                SLIST_INSERT_HEAD(&sim->ccb_freeq, &new_ccb->ccb_h,
                                  xpt_links.sle);
                sim->ccb_count++;
        }
        cam_ccbq_take_opening(&device->ccbq);
        SLIST_REMOVE_HEAD(&sim->ccb_freeq, xpt_links.sle);
        return (new_ccb);
}

static void
xpt_release_bus(struct cam_eb *bus)
{
        for (;;) {
                int count = bus->refcount;

                cpu_ccfence();
                if (count == 1) {
                        lockmgr(&xsoftc.xpt_topo_lock, LK_EXCLUSIVE);
                        if (atomic_cmpset_int(&bus->refcount, 1, 0)) {
                                if (TAILQ_EMPTY(&bus->et_entries)) {
                                        TAILQ_REMOVE(&xsoftc.xpt_busses,
                                                     bus, links);
                                        xsoftc.bus_generation++;
                                        kfree(bus, M_CAMXPT);
                                }
                                lockmgr(&xsoftc.xpt_topo_lock, LK_RELEASE);
                                return;
                        }
                        lockmgr(&xsoftc.xpt_topo_lock, LK_RELEASE);
                } else {
                        if (atomic_cmpset_int(&bus->refcount, count, count-1)) {
                                return;
                        }
                }
        }
}

static struct cam_et *
xpt_alloc_target(struct cam_eb *bus, target_id_t target_id)
{
        struct cam_et *target;
        struct cam_et *cur_target;

        target = kmalloc(sizeof(*target), M_CAMXPT, M_INTWAIT);

        TAILQ_INIT(&target->ed_entries);
        target->bus = bus;
        target->target_id = target_id;
        target->refcount = 1;
        target->generation = 0;
        timevalclear(&target->last_reset);

        /*
         * Hold a reference to our parent bus so it
         * will not go away before we do.
         */
        atomic_add_int(&bus->refcount, 1);

        lockmgr(&xsoftc.xpt_topo_lock, LK_EXCLUSIVE);
        /* Insertion sort into our bus's target list */
        cur_target = TAILQ_FIRST(&bus->et_entries);
        while (cur_target != NULL && cur_target->target_id < target_id)
                cur_target = TAILQ_NEXT(cur_target, links);

        if (cur_target != NULL) {
                TAILQ_INSERT_BEFORE(cur_target, target, links);
        } else {
                TAILQ_INSERT_TAIL(&bus->et_entries, target, links);
        }
        bus->generation++;
        lockmgr(&xsoftc.xpt_topo_lock, LK_RELEASE);

        return (target);
}

static void
xpt_release_target(struct cam_eb *bus, struct cam_et *target)
{
        for (;;) {
                int count = target->refcount;

                cpu_ccfence();
                if (count == 1) {
                        lockmgr(&xsoftc.xpt_topo_lock, LK_EXCLUSIVE);
                        if (atomic_cmpset_int(&target->refcount, 1, 0)) {
                                KKASSERT(TAILQ_EMPTY(&target->ed_entries));
                                TAILQ_REMOVE(&bus->et_entries, target, links);
                                bus->generation++;
                                kfree(target, M_CAMXPT);
                                lockmgr(&xsoftc.xpt_topo_lock, LK_RELEASE);
                                xpt_release_bus(bus);
                                return;
                        }
                        lockmgr(&xsoftc.xpt_topo_lock, LK_RELEASE);
                } else {
                        if (atomic_cmpset_int(&target->refcount,
                                              count, count - 1)) {
                                return;
                        }
                }
        }
}

static struct cam_ed *
xpt_alloc_device(struct cam_eb *bus, struct cam_et *target, lun_id_t lun_id)
{
        struct     cam_path path;
        struct     cam_ed *device;
        struct     cam_devq *devq;
        cam_status status;

        /*
         * Disallow new devices while trying to deregister a sim
         */
        if (bus->sim->flags & CAM_SIM_DEREGISTERED)
                return (NULL);

        /*
         * Make space for us in the device queue on our bus
         */
        lockmgr(&xsoftc.xpt_topo_lock, LK_EXCLUSIVE);
        devq = bus->sim->devq;
        if (devq == NULL) {
                lockmgr(&xsoftc.xpt_topo_lock, LK_RELEASE);
                return(NULL);
        }
        status = cam_devq_resize(devq, devq->alloc_queue.array_size + 1);
        lockmgr(&xsoftc.xpt_topo_lock, LK_RELEASE);

        if (status != CAM_REQ_CMP) {
                device = NULL;
        } else {
                device = kmalloc(sizeof(*device), M_CAMXPT, M_INTWAIT);
        }

        if (device != NULL) {
                struct cam_ed *cur_device;

                cam_init_pinfo(&device->alloc_ccb_entry.pinfo);
                device->alloc_ccb_entry.device = device;
                cam_init_pinfo(&device->send_ccb_entry.pinfo);
                device->send_ccb_entry.device = device;
                device->target = target;
                device->lun_id = lun_id;
                device->sim = bus->sim;
                /* Initialize our queues */
                if (camq_init(&device->drvq, 0) != 0) {
                        kfree(device, M_CAMXPT);
                        return (NULL);
                }
                if (cam_ccbq_init(&device->ccbq,
                                  bus->sim->max_dev_openings) != 0) {
                        camq_fini(&device->drvq);
                        kfree(device, M_CAMXPT);
                        return (NULL);
                }
                SLIST_INIT(&device->asyncs);
                SLIST_INIT(&device->periphs);
                device->generation = 0;
                device->owner = NULL;
                /*
                 * Take the default quirk entry until we have inquiry
                 * data and can determine a better quirk to use.
                 */
                device->quirk = &xpt_quirk_table[xpt_quirk_table_size - 1];
                bzero(&device->inq_data, sizeof(device->inq_data));
                device->inq_flags = 0;
                device->queue_flags = 0;
                device->serial_num = NULL;
                device->serial_num_len = 0;
                device->qfrozen_cnt = 0;
                device->flags = CAM_DEV_UNCONFIGURED;
                device->tag_delay_count = 0;
                device->tag_saved_openings = 0;
                device->refcount = 1;
                callout_init(&device->callout);

                /*
                 * Hold a reference to our parent target so it
                 * will not go away before we do.
                 */
                atomic_add_int(&target->refcount, 1);

                /*
                 * XXX should be limited by number of CCBs this bus can
                 * do.
                 */
                bus->sim->max_ccbs += device->ccbq.devq_openings;
                /* Insertion sort into our target's device list */
                cur_device = TAILQ_FIRST(&target->ed_entries);
                while (cur_device != NULL && cur_device->lun_id < lun_id)
                        cur_device = TAILQ_NEXT(cur_device, links);
                if (cur_device != NULL) {
                        TAILQ_INSERT_BEFORE(cur_device, device, links);
                } else {
                        TAILQ_INSERT_TAIL(&target->ed_entries, device, links);
                }
                target->generation++;
                if (lun_id != CAM_LUN_WILDCARD) {
                        xpt_compile_path(&path,
                                         NULL,
                                         bus->path_id,
                                         target->target_id,
                                         lun_id);
                        xpt_devise_transport(&path);
                        xpt_release_path(&path);
                }
        }
        return (device);
}

static void
xpt_reference_device(struct cam_ed *device)
{
        atomic_add_int(&device->refcount, 1);
}

static void
xpt_release_device(struct cam_eb *bus, struct cam_et *target,
                   struct cam_ed *device)
{
        struct cam_devq *devq;

        for (;;) {
                int count = device->refcount;

                if (count == 1) {
                        lockmgr(&xsoftc.xpt_topo_lock, LK_EXCLUSIVE);
                        if (atomic_cmpset_int(&device->refcount, 1, 0)) {
                                KKASSERT(device->flags & CAM_DEV_UNCONFIGURED);
                                if (device->alloc_ccb_entry.pinfo.index !=
                                     CAM_UNQUEUED_INDEX ||
                                    device->send_ccb_entry.pinfo.index !=
                                     CAM_UNQUEUED_INDEX) {
                                        panic("Removing device while "
                                              "still queued for ccbs");
                                }
                                if ((device->flags & CAM_DEV_REL_TIMEOUT_PENDING) != 0) {
                                        device->flags &= ~CAM_DEV_REL_TIMEOUT_PENDING;
                                        callout_stop(&device->callout);
                                }
                                TAILQ_REMOVE(&target->ed_entries, device, links);
                                target->generation++;
                                bus->sim->max_ccbs -= device->ccbq.devq_openings;
                                if ((devq = bus->sim->devq) != NULL) {
                                        /* Release our slot in the devq */
                                        cam_devq_resize(devq, devq->alloc_queue.array_size - 1);
                                }
                                lockmgr(&xsoftc.xpt_topo_lock, LK_RELEASE);

                                camq_fini(&device->drvq);
                                camq_fini(&device->ccbq.queue);
                                xpt_release_target(bus, target);
                                kfree(device, M_CAMXPT);
                                return;
                        }
                        lockmgr(&xsoftc.xpt_topo_lock, LK_RELEASE);
                } else {
                        if (atomic_cmpset_int(&device->refcount,
                                              count, count - 1)) {
                                return;
                        }
                }
        }
}

static u_int32_t
xpt_dev_ccbq_resize(struct cam_path *path, int newopenings)
{
        int     diff;
        int     result;
        struct  cam_ed *dev;

        dev = path->device;

        diff = newopenings - (dev->ccbq.dev_active + dev->ccbq.dev_openings);
        result = cam_ccbq_resize(&dev->ccbq, newopenings);
        if (result == CAM_REQ_CMP && (diff < 0)) {
                dev->flags |= CAM_DEV_RESIZE_QUEUE_NEEDED;
        }
        if ((dev->flags & CAM_DEV_TAG_AFTER_COUNT) != 0
         || (dev->inq_flags & SID_CmdQue) != 0)
                dev->tag_saved_openings = newopenings;
        /* Adjust the global limit */
        dev->sim->max_ccbs += diff;
        return (result);
}

static struct cam_eb *
xpt_find_bus(path_id_t path_id)
{
        struct cam_eb *bus;

        lockmgr(&xsoftc.xpt_topo_lock, LK_EXCLUSIVE);
        TAILQ_FOREACH(bus, &xsoftc.xpt_busses, links) {
                if (bus->path_id == path_id) {
                        atomic_add_int(&bus->refcount, 1);
                        break;
                }
        }
        lockmgr(&xsoftc.xpt_topo_lock, LK_RELEASE);

        return (bus);
}

static struct cam_et *
xpt_find_target(struct cam_eb *bus, target_id_t target_id)
{
        struct cam_et *target;

        lockmgr(&xsoftc.xpt_topo_lock, LK_EXCLUSIVE);
        TAILQ_FOREACH(target, &bus->et_entries, links) {
                if (target->target_id == target_id) {
                        atomic_add_int(&target->refcount, 1);
                        break;
                }
        }
        lockmgr(&xsoftc.xpt_topo_lock, LK_RELEASE);

        return (target);
}

static struct cam_ed *
xpt_find_device(struct cam_et *target, lun_id_t lun_id)
{
        struct cam_ed *device;

        lockmgr(&xsoftc.xpt_topo_lock, LK_EXCLUSIVE);
        TAILQ_FOREACH(device, &target->ed_entries, links) {
                if (device->lun_id == lun_id) {
                        atomic_add_int(&device->refcount, 1);
                        break;
                }
        }
        lockmgr(&xsoftc.xpt_topo_lock, LK_RELEASE);

        return (device);
}

typedef struct {
        union   ccb *request_ccb;
        struct  ccb_pathinq *cpi;
        int     counter;
} xpt_scan_bus_info;

/*
 * To start a scan, request_ccb is an XPT_SCAN_BUS ccb.
 * As the scan progresses, xpt_scan_bus is used as the
 * callback on completion function.
 */
static void
xpt_scan_bus(struct cam_periph *periph, union ccb *request_ccb)
{
        CAM_DEBUG(request_ccb->ccb_h.path, CAM_DEBUG_TRACE,
                  ("xpt_scan_bus\n"));
        switch (request_ccb->ccb_h.func_code) {
        case XPT_SCAN_BUS:
        {
                xpt_scan_bus_info *scan_info;
                union   ccb *work_ccb;
                struct  cam_path *path;
                u_int   i;
                u_int   max_target;
                u_int   initiator_id;

                /* Find out the characteristics of the bus */
                work_ccb = xpt_alloc_ccb();
                xpt_setup_ccb(&work_ccb->ccb_h, request_ccb->ccb_h.path,
                              request_ccb->ccb_h.pinfo.priority);
                work_ccb->ccb_h.func_code = XPT_PATH_INQ;
                xpt_action(work_ccb);
                if (work_ccb->ccb_h.status != CAM_REQ_CMP) {
                        request_ccb->ccb_h.status = work_ccb->ccb_h.status;
                        xpt_free_ccb(&work_ccb->ccb_h);
                        xpt_done(request_ccb);
                        return;
                }

                if ((work_ccb->cpi.hba_misc & PIM_NOINITIATOR) != 0) {
                        /*
                         * Can't scan the bus on an adapter that
                         * cannot perform the initiator role.
                         */
                        request_ccb->ccb_h.status = CAM_REQ_CMP;
                        xpt_free_ccb(&work_ccb->ccb_h);
                        xpt_done(request_ccb);
                        return;
                }

                /* Save some state for use while we probe for devices */
                scan_info = (xpt_scan_bus_info *)
                    kmalloc(sizeof(xpt_scan_bus_info), M_CAMXPT, M_INTWAIT);
                scan_info->request_ccb = request_ccb;
                scan_info->cpi = &work_ccb->cpi;

                /* Cache on our stack so we can work asynchronously */
                max_target = scan_info->cpi->max_target;
                initiator_id = scan_info->cpi->initiator_id;


                /*
                 * We can scan all targets in parallel, or do it sequentially.
                 */
                if (scan_info->cpi->hba_misc & PIM_SEQSCAN) {
                        max_target = 0;
                        scan_info->counter = 0;
                } else {
                        scan_info->counter = scan_info->cpi->max_target + 1;
                        if (scan_info->cpi->initiator_id < scan_info->counter) {
                                scan_info->counter--;
                        }
                }

                for (i = 0; i <= max_target; i++) {
                        cam_status status;
                        if (i == initiator_id)
                                continue;

                        status = xpt_create_path(&path, xpt_periph,
                                                 request_ccb->ccb_h.path_id,
                                                 i, 0);
                        if (status != CAM_REQ_CMP) {
                                kprintf("xpt_scan_bus: xpt_create_path failed"
                                       " with status %#x, bus scan halted\n",
                                       status);
                                kfree(scan_info, M_CAMXPT);
                                request_ccb->ccb_h.status = status;
                                xpt_free_ccb(&work_ccb->ccb_h);
                                xpt_done(request_ccb);
                                break;
                        }
                        work_ccb = xpt_alloc_ccb();
                        xpt_setup_ccb(&work_ccb->ccb_h, path,
                                      request_ccb->ccb_h.pinfo.priority);
                        work_ccb->ccb_h.func_code = XPT_SCAN_LUN;
                        work_ccb->ccb_h.cbfcnp = xpt_scan_bus;
                        work_ccb->ccb_h.ppriv_ptr0 = scan_info;
                        work_ccb->crcn.flags = request_ccb->crcn.flags;
                        xpt_action(work_ccb);
                }
                break;
        }
        case XPT_SCAN_LUN:
        {
                cam_status status;
                struct cam_path *path;
                xpt_scan_bus_info *scan_info;
                path_id_t path_id;
                target_id_t target_id;
                lun_id_t lun_id;

                /* Reuse the same CCB to query if a device was really found */
                scan_info = (xpt_scan_bus_info *)request_ccb->ccb_h.ppriv_ptr0;
                xpt_setup_ccb(&request_ccb->ccb_h, request_ccb->ccb_h.path,
                              request_ccb->ccb_h.pinfo.priority);
                request_ccb->ccb_h.func_code = XPT_GDEV_TYPE;

                path_id = request_ccb->ccb_h.path_id;
                target_id = request_ccb->ccb_h.target_id;
                lun_id = request_ccb->ccb_h.target_lun;
                xpt_action(request_ccb);

                if (request_ccb->ccb_h.status != CAM_REQ_CMP) {
                        struct cam_ed *device;
                        struct cam_et *target;
                        int phl;

                        /*
                         * If we already probed lun 0 successfully, or
                         * we have additional configured luns on this
                         * target that might have "gone away", go onto
                         * the next lun.
                         */
                        target = request_ccb->ccb_h.path->target;
                        /*
                         * We may touch devices that we don't
                         * hold references too, so ensure they
                         * don't disappear out from under us.
                         * The target above is referenced by the
                         * path in the request ccb.
                         */
                        phl = 0;
                        device = TAILQ_FIRST(&target->ed_entries);
                        if (device != NULL) {
                                phl = CAN_SRCH_HI_SPARSE(device);
                                if (device->lun_id == 0)
                                        device = TAILQ_NEXT(device, links);
                        }
                        if ((lun_id != 0) || (device != NULL)) {
                                if (lun_id < (CAM_SCSI2_MAXLUN-1) || phl)
                                        lun_id++;
                        }
                } else {
                        struct cam_ed *device;

                        device = request_ccb->ccb_h.path->device;

                        if ((device->quirk->quirks & CAM_QUIRK_NOLUNS) == 0) {
                                /* Try the next lun */
                                if (lun_id < (CAM_SCSI2_MAXLUN-1)
                                  || CAN_SRCH_HI_DENSE(device))
                                        lun_id++;
                        }
                }

                /*
                 * Free the current request path- we're done with it.
                 */
                xpt_free_path(request_ccb->ccb_h.path);

                /*
                 * Check to see if we scan any further luns.
                 */
                if (lun_id == request_ccb->ccb_h.target_lun
                 || lun_id > scan_info->cpi->max_lun) {
                        int done;

 hop_again:
                        done = 0;
                        if (scan_info->cpi->hba_misc & PIM_SEQSCAN) {
                                scan_info->counter++;
                                if (scan_info->counter ==
                                    scan_info->cpi->initiator_id) {
                                        scan_info->counter++;
                                }
                                if (scan_info->counter >=
                                    scan_info->cpi->max_target+1) {
                                        done = 1;
                                }
                        } else {
                                scan_info->counter--;
                                if (scan_info->counter == 0) {
                                        done = 1;
                                }
                        }
                        if (done) {
                                xpt_free_ccb(&request_ccb->ccb_h);
                                xpt_free_ccb(&scan_info->cpi->ccb_h);
                                request_ccb = scan_info->request_ccb;
                                kfree(scan_info, M_CAMXPT);
                                request_ccb->ccb_h.status = CAM_REQ_CMP;
                                xpt_done(request_ccb);
                                break;
                        }

                        if ((scan_info->cpi->hba_misc & PIM_SEQSCAN) == 0) {
                                break;
                        }
                        status = xpt_create_path(&path, xpt_periph,
                            scan_info->request_ccb->ccb_h.path_id,
                            scan_info->counter, 0);
                        if (status != CAM_REQ_CMP) {
                                kprintf("xpt_scan_bus: xpt_create_path failed"
                                    " with status %#x, bus scan halted\n",
                                    status);
                                xpt_free_ccb(&request_ccb->ccb_h);
                                xpt_free_ccb(&scan_info->cpi->ccb_h);
                                request_ccb = scan_info->request_ccb;
                                kfree(scan_info, M_CAMXPT);
                                request_ccb->ccb_h.status = status;
                                xpt_done(request_ccb);
                                break;
                        }
                        xpt_setup_ccb(&request_ccb->ccb_h, path,
                                      request_ccb->ccb_h.pinfo.priority);
                        request_ccb->ccb_h.func_code = XPT_SCAN_LUN;
                        request_ccb->ccb_h.cbfcnp = xpt_scan_bus;
                        request_ccb->ccb_h.ppriv_ptr0 = scan_info;
                        request_ccb->crcn.flags =
                            scan_info->request_ccb->crcn.flags;
                } else {
                        status = xpt_create_path(&path, xpt_periph,
                                                 path_id, target_id, lun_id);
                        if (status != CAM_REQ_CMP) {
                                kprintf("xpt_scan_bus: xpt_create_path failed "
                                       "with status %#x, halting LUN scan\n",
                                       status);
                                goto hop_again;
                        }
                        xpt_setup_ccb(&request_ccb->ccb_h, path,
                                      request_ccb->ccb_h.pinfo.priority);
                        request_ccb->ccb_h.func_code = XPT_SCAN_LUN;
                        request_ccb->ccb_h.cbfcnp = xpt_scan_bus;
                        request_ccb->ccb_h.ppriv_ptr0 = scan_info;
                        request_ccb->crcn.flags =
                                scan_info->request_ccb->crcn.flags;
                }
                xpt_action(request_ccb);
                break;
        }
        default:
                break;
        }
}

typedef enum {
        PROBE_TUR,
        PROBE_INQUIRY,  /* this counts as DV0 for Basic Domain Validation */
        PROBE_FULL_INQUIRY,
        PROBE_MODE_SENSE,
        PROBE_SERIAL_NUM_0,
        PROBE_SERIAL_NUM_1,
        PROBE_TUR_FOR_NEGOTIATION,
        PROBE_INQUIRY_BASIC_DV1,
        PROBE_INQUIRY_BASIC_DV2,
        PROBE_DV_EXIT,
        PROBE_INVALID
} probe_action;

static char *probe_action_text[] = {
        "PROBE_TUR",
        "PROBE_INQUIRY",
        "PROBE_FULL_INQUIRY",
        "PROBE_MODE_SENSE",
        "PROBE_SERIAL_NUM_0",
        "PROBE_SERIAL_NUM_1",
        "PROBE_TUR_FOR_NEGOTIATION",
        "PROBE_INQUIRY_BASIC_DV1",
        "PROBE_INQUIRY_BASIC_DV2",
        "PROBE_DV_EXIT",
        "PROBE_INVALID"
};

#define PROBE_SET_ACTION(softc, newaction)      \
do {                                                                    \
        char **text;                                                    \
        text = probe_action_text;                                       \
        CAM_DEBUG((softc)->periph->path, CAM_DEBUG_INFO,                \
            ("Probe %s to %s\n", text[(softc)->action],                 \
            text[(newaction)]));                                        \
        (softc)->action = (newaction);                                  \
} while(0)

typedef enum {
        PROBE_INQUIRY_CKSUM     = 0x01,
        PROBE_SERIAL_CKSUM      = 0x02,
        PROBE_NO_ANNOUNCE       = 0x04
} probe_flags;

typedef struct {
        TAILQ_HEAD(, ccb_hdr) request_ccbs;
        probe_action    action;
        union ccb       saved_ccb;
        probe_flags     flags;
        MD5_CTX         context;
        u_int8_t        digest[16];
        struct cam_periph *periph;
} probe_softc; 

static void
xpt_scan_lun(struct cam_periph *periph, struct cam_path *path,
             cam_flags flags, union ccb *request_ccb)
{
        struct ccb_pathinq *cpi;
        cam_status status;
        struct cam_path *new_path;
        struct cam_periph *old_periph;
        
        CAM_DEBUG(request_ccb->ccb_h.path, CAM_DEBUG_TRACE,
                  ("xpt_scan_lun\n"));

        cpi = &xpt_alloc_ccb()->cpi;
        xpt_setup_ccb(&cpi->ccb_h, path, /*priority*/1);
        cpi->ccb_h.func_code = XPT_PATH_INQ;
        xpt_action((union ccb *)cpi);

        if (cpi->ccb_h.status != CAM_REQ_CMP) {
                if (request_ccb != NULL) {
                        request_ccb->ccb_h.status = cpi->ccb_h.status;
                        xpt_done(request_ccb);
                }
                xpt_free_ccb(&cpi->ccb_h);
                return;
        }

        if ((cpi->hba_misc & PIM_NOINITIATOR) != 0) {
                /*
                 * Can't scan the bus on an adapter that
                 * cannot perform the initiator role.
                 */
                if (request_ccb != NULL) {
                        request_ccb->ccb_h.status = CAM_REQ_CMP;
                        xpt_done(request_ccb);
                }
                xpt_free_ccb(&cpi->ccb_h);
                return;
        }
        xpt_free_ccb(&cpi->ccb_h);

        if (request_ccb == NULL) {
                request_ccb = xpt_alloc_ccb();
                new_path = kmalloc(sizeof(*new_path), M_CAMXPT, M_INTWAIT);
                status = xpt_compile_path(new_path, xpt_periph,
                                          path->bus->path_id,
                                          path->target->target_id,
                                          path->device->lun_id);

                if (status != CAM_REQ_CMP) {
                        xpt_print(path, "xpt_scan_lun: can't compile path, "
                            "can't continue\n");
                        xpt_free_ccb(&request_ccb->ccb_h);
                        kfree(new_path, M_CAMXPT);
                        return;
                }
                xpt_setup_ccb(&request_ccb->ccb_h, new_path, /*priority*/ 1);
                request_ccb->ccb_h.cbfcnp = xptscandone;
                request_ccb->ccb_h.func_code = XPT_SCAN_LUN;
                request_ccb->crcn.flags = flags;
        }

        if ((old_periph = cam_periph_find(path, "probe")) != NULL) {
                probe_softc *softc;

                softc = (probe_softc *)old_periph->softc;
                TAILQ_INSERT_TAIL(&softc->request_ccbs, &request_ccb->ccb_h,
                                  periph_links.tqe);
        } else {
                status = cam_periph_alloc(proberegister, NULL, probecleanup,
                                          probestart, "probe",
                                          CAM_PERIPH_BIO,
                                          request_ccb->ccb_h.path, NULL, 0,
                                          request_ccb);

                if (status != CAM_REQ_CMP) {
                        xpt_print(path, "xpt_scan_lun: cam_alloc_periph "
                            "returned an error, can't continue probe\n");
                        request_ccb->ccb_h.status = status;
                        xpt_done(request_ccb);
                }
        }
}

static void
xptscandone(struct cam_periph *periph, union ccb *done_ccb)
{
        xpt_release_path(done_ccb->ccb_h.path);
        kfree(done_ccb->ccb_h.path, M_CAMXPT);
        xpt_free_ccb(&done_ccb->ccb_h);
}

static cam_status
proberegister(struct cam_periph *periph, void *arg)
{
        union ccb *request_ccb; /* CCB representing the probe request */
        cam_status status;
        probe_softc *softc;

        request_ccb = (union ccb *)arg;
        if (periph == NULL) {
                kprintf("proberegister: periph was NULL!!\n");
                return(CAM_REQ_CMP_ERR);
        }

        if (request_ccb == NULL) {
                kprintf("proberegister: no probe CCB, "
                       "can't register device\n");
                return(CAM_REQ_CMP_ERR);
        }

        softc = kmalloc(sizeof(*softc), M_CAMXPT, M_INTWAIT | M_ZERO);
        TAILQ_INIT(&softc->request_ccbs);
        TAILQ_INSERT_TAIL(&softc->request_ccbs, &request_ccb->ccb_h,
                          periph_links.tqe);
        softc->flags = 0;
        periph->softc = softc;
        softc->periph = periph;
        softc->action = PROBE_INVALID;
        status = cam_periph_acquire(periph);
        if (status != CAM_REQ_CMP) {
                return (status);
        }


        /*
         * Ensure we've waited at least a bus settle
         * delay before attempting to probe the device.
         * For HBAs that don't do bus resets, this won't make a difference.
         */
        cam_periph_freeze_after_event(periph, &periph->path->bus->last_reset,
                                      scsi_delay);
        probeschedule(periph);
        return(CAM_REQ_CMP);
}

static void
probeschedule(struct cam_periph *periph)
{
        struct ccb_pathinq *cpi;
        union ccb *ccb;
        probe_softc *softc;

        softc = (probe_softc *)periph->softc;
        ccb = (union ccb *)TAILQ_FIRST(&softc->request_ccbs);

        cpi = &xpt_alloc_ccb()->cpi;
        xpt_setup_ccb(&cpi->ccb_h, periph->path, /*priority*/1);
        cpi->ccb_h.func_code = XPT_PATH_INQ;
        xpt_action((union ccb *)cpi);

        /*
         * If a device has gone away and another device, or the same one,
         * is back in the same place, it should have a unit attention
         * condition pending.  It will not report the unit attention in
         * response to an inquiry, which may leave invalid transfer
         * negotiations in effect.  The TUR will reveal the unit attention
         * condition.  Only send the TUR for lun 0, since some devices
         * will get confused by commands other than inquiry to non-existent
         * luns.  If you think a device has gone away start your scan from
         * lun 0.  This will insure that any bogus transfer settings are
         * invalidated.
         *
         * If we haven't seen the device before and the controller supports
         * some kind of transfer negotiation, negotiate with the first
         * sent command if no bus reset was performed at startup.  This
         * ensures that the device is not confused by transfer negotiation
         * settings left over by loader or BIOS action.
         */
        if (((ccb->ccb_h.path->device->flags & CAM_DEV_UNCONFIGURED) == 0)
         && (ccb->ccb_h.target_lun == 0)) {
                PROBE_SET_ACTION(softc, PROBE_TUR);
        } else if ((cpi->hba_inquiry & (PI_WIDE_32|PI_WIDE_16|PI_SDTR_ABLE)) != 0
              && (cpi->hba_misc & PIM_NOBUSRESET) != 0) {
                proberequestdefaultnegotiation(periph);
                PROBE_SET_ACTION(softc, PROBE_INQUIRY);
        } else {
                PROBE_SET_ACTION(softc, PROBE_INQUIRY);
        }

        if (ccb->crcn.flags & CAM_EXPECT_INQ_CHANGE)
                softc->flags |= PROBE_NO_ANNOUNCE;
        else
                softc->flags &= ~PROBE_NO_ANNOUNCE;

        xpt_schedule(periph, ccb->ccb_h.pinfo.priority);
        xpt_free_ccb(&cpi->ccb_h);
}

static void
probestart(struct cam_periph *periph, union ccb *start_ccb)
{
        /* Probe the device that our peripheral driver points to */
        struct ccb_scsiio *csio;
        probe_softc *softc;

        CAM_DEBUG(start_ccb->ccb_h.path, CAM_DEBUG_TRACE, ("probestart\n"));

        softc = (probe_softc *)periph->softc;
        csio = &start_ccb->csio;

        switch (softc->action) {
        case PROBE_TUR:
        case PROBE_TUR_FOR_NEGOTIATION:
        case PROBE_DV_EXIT:
        {
                scsi_test_unit_ready(csio,
                                     /*retries*/4,
                                     probedone,
                                     MSG_SIMPLE_Q_TAG,
                                     SSD_FULL_SIZE,
                                     /*timeout*/60000);
                break;
        }
        case PROBE_INQUIRY:
        case PROBE_FULL_INQUIRY:
        case PROBE_INQUIRY_BASIC_DV1:
        case PROBE_INQUIRY_BASIC_DV2:
        {
                u_int inquiry_len;
                struct scsi_inquiry_data *inq_buf;

                inq_buf = &periph->path->device->inq_data;

                /*
                 * If the device is currently configured, we calculate an
                 * MD5 checksum of the inquiry data, and if the serial number
                 * length is greater than 0, add the serial number data
                 * into the checksum as well.  Once the inquiry and the
                 * serial number check finish, we attempt to figure out
                 * whether we still have the same device.
                 */
                if ((periph->path->device->flags & CAM_DEV_UNCONFIGURED) == 0) {

                        MD5Init(&softc->context);
                        MD5Update(&softc->context, (unsigned char *)inq_buf,
                                  sizeof(struct scsi_inquiry_data));
                        softc->flags |= PROBE_INQUIRY_CKSUM;
                        if (periph->path->device->serial_num_len > 0) {
                                MD5Update(&softc->context,
                                          periph->path->device->serial_num,
                                          periph->path->device->serial_num_len);
                                softc->flags |= PROBE_SERIAL_CKSUM;
                        }
                        MD5Final(softc->digest, &softc->context);
                }

                if (softc->action == PROBE_INQUIRY)
                        inquiry_len = SHORT_INQUIRY_LENGTH;
                else
                        inquiry_len = SID_ADDITIONAL_LENGTH(inq_buf);

                /*
                 * Some parallel SCSI devices fail to send an
                 * ignore wide residue message when dealing with
                 * odd length inquiry requests.  Round up to be
                 * safe.
                 */
                inquiry_len = roundup2(inquiry_len, 2);

                if (softc->action == PROBE_INQUIRY_BASIC_DV1
                 || softc->action == PROBE_INQUIRY_BASIC_DV2) {
                        inq_buf = kmalloc(inquiry_len, M_CAMXPT, M_INTWAIT);
                }
                scsi_inquiry(csio,
                             /*retries*/4,
                             probedone,
                             MSG_SIMPLE_Q_TAG,
                             (u_int8_t *)inq_buf,
                             inquiry_len,
                             /*evpd*/FALSE,
                             /*page_code*/0,
                             SSD_MIN_SIZE,
                             /*timeout*/60 * 1000);
                break;
        }
        case PROBE_MODE_SENSE:
        {
                void  *mode_buf;
                int    mode_buf_len;

                mode_buf_len = sizeof(struct scsi_mode_header_6)
                             + sizeof(struct scsi_mode_blk_desc)
                             + sizeof(struct scsi_control_page);
                mode_buf = kmalloc(mode_buf_len, M_CAMXPT, M_INTWAIT);
                scsi_mode_sense(csio,
                                /*retries*/4,
                                probedone,
                                MSG_SIMPLE_Q_TAG,
                                /*dbd*/FALSE,
                                SMS_PAGE_CTRL_CURRENT,
                                SMS_CONTROL_MODE_PAGE,
                                mode_buf,
                                mode_buf_len,
                                SSD_FULL_SIZE,
                                /*timeout*/60000);
                break;
        }
        case PROBE_SERIAL_NUM_0:
        {
                struct scsi_vpd_supported_page_list *vpd_list = NULL;
                struct cam_ed *device;

                device = periph->path->device;
                if ((device->quirk->quirks & CAM_QUIRK_NOSERIAL) == 0) {
                        vpd_list = kmalloc(sizeof(*vpd_list), M_CAMXPT,
                            M_INTWAIT | M_ZERO);
                }

                if (vpd_list != NULL) {
                        scsi_inquiry(csio,
                                     /*retries*/4,
                                     probedone,
                                     MSG_SIMPLE_Q_TAG,
                                     (u_int8_t *)vpd_list,
                                     sizeof(*vpd_list),
                                     /*evpd*/TRUE,
                                     SVPD_SUPPORTED_PAGE_LIST,
                                     SSD_MIN_SIZE,
                                     /*timeout*/60 * 1000);
                        break;
                }
                /*
                 * We'll have to do without, let our probedone
                 * routine finish up for us.
                 */
                start_ccb->csio.data_ptr = NULL;
                probedone(periph, start_ccb);
                return;
        }
        case PROBE_SERIAL_NUM_1:
        {
                struct scsi_vpd_unit_serial_number *serial_buf;
                struct cam_ed* device;

                serial_buf = NULL;
                device = periph->path->device;
                device->serial_num = NULL;
                device->serial_num_len = 0;

                serial_buf = (struct scsi_vpd_unit_serial_number *)
                        kmalloc(sizeof(*serial_buf), M_CAMXPT,
                                M_INTWAIT | M_ZERO);
                scsi_inquiry(csio,
                             /*retries*/4,
                             probedone,
                             MSG_SIMPLE_Q_TAG,
                             (u_int8_t *)serial_buf,
                             sizeof(*serial_buf),
                             /*evpd*/TRUE,
                             SVPD_UNIT_SERIAL_NUMBER,
                             SSD_MIN_SIZE,
                             /*timeout*/60 * 1000);
                break;
        }
        case PROBE_INVALID:
                CAM_DEBUG(start_ccb->ccb_h.path, CAM_DEBUG_INFO,
                    ("probestart: invalid action state\n"));
        default:
                break;
        }
        xpt_action(start_ccb);
}

static void
proberequestdefaultnegotiation(struct cam_periph *periph)
{
        struct ccb_trans_settings *cts;

        cts = &xpt_alloc_ccb()->cts;
        xpt_setup_ccb(&cts->ccb_h, periph->path, /*priority*/1);
        cts->ccb_h.func_code = XPT_GET_TRAN_SETTINGS;
        cts->type = CTS_TYPE_USER_SETTINGS;
        xpt_action((union ccb *)cts);
        if ((cts->ccb_h.status & CAM_STATUS_MASK) != CAM_REQ_CMP) {
                xpt_free_ccb(&cts->ccb_h);
                return;
        }
        cts->ccb_h.func_code = XPT_SET_TRAN_SETTINGS;
        cts->type = CTS_TYPE_CURRENT_SETTINGS;
        xpt_action((union ccb *)cts);
        xpt_free_ccb(&cts->ccb_h);
}

/*
 * Backoff Negotiation Code- only pertinent for SPI devices.
 */
static int
proberequestbackoff(struct cam_periph *periph, struct cam_ed *device)
{
        struct ccb_trans_settings *cts;
        struct ccb_trans_settings_spi *spi;
        int result;

        result = 0;
        cts = &xpt_alloc_ccb()->cts;
        xpt_setup_ccb(&cts->ccb_h, periph->path, /*priority*/1);
        cts->ccb_h.func_code = XPT_GET_TRAN_SETTINGS;
        cts->type = CTS_TYPE_CURRENT_SETTINGS;
        xpt_action((union ccb *)cts);
        if ((cts->ccb_h.status & CAM_STATUS_MASK) != CAM_REQ_CMP) {
                if (bootverbose) {
                        xpt_print(periph->path,
                            "failed to get current device settings\n");
                }
                goto done;
        }
        if (cts->transport != XPORT_SPI) {
                if (bootverbose) {
                        xpt_print(periph->path, "not SPI transport\n");
                }
                goto done;
        }
        spi = &cts->xport_specific.spi;

        /*
         * We cannot renegotiate sync rate if we don't have one.
         */
        if ((spi->valid & CTS_SPI_VALID_SYNC_RATE) == 0) {
                if (bootverbose) {
                        xpt_print(periph->path, "no sync rate known\n");
                }
                goto done;
        }

        /*
         * We'll assert that we don't have to touch PPR options- the
         * SIM will see what we do with period and offset and adjust
         * the PPR options as appropriate.
         */

        /*
         * A sync rate with unknown or zero offset is nonsensical.
         * A sync period of zero means Async.
         */
        if ((spi->valid & CTS_SPI_VALID_SYNC_OFFSET) == 0
         || spi->sync_offset == 0 || spi->sync_period == 0) {
                if (bootverbose) {
                        xpt_print(periph->path, "no sync rate available\n");
                }
                goto done;
        }

        if (device->flags & CAM_DEV_DV_HIT_BOTTOM) {
                CAM_DEBUG(periph->path, CAM_DEBUG_INFO,
                    ("hit async: giving up on DV\n"));
                goto done;
        }


        /*
         * Jump sync_period up by one, but stop at 5MHz and fall back to Async.
         * We don't try to remember 'last' settings to see if the SIM actually
         * gets into the speed we want to set. We check on the SIM telling
         * us that a requested speed is bad, but otherwise don't try and
         * check the speed due to the asynchronous and handshake nature
         * of speed setting.
         */
        spi->valid = CTS_SPI_VALID_SYNC_RATE | CTS_SPI_VALID_SYNC_OFFSET;
        for (;;) {
                spi->sync_period++;
                if (spi->sync_period >= 0xf) {
                        spi->sync_period = 0;
                        spi->sync_offset = 0;
                        CAM_DEBUG(periph->path, CAM_DEBUG_INFO,
                            ("setting to async for DV\n"));
                        /*
                         * Once we hit async, we don't want to try
                         * any more settings.
                         */
                        device->flags |= CAM_DEV_DV_HIT_BOTTOM;
                } else if (bootverbose) {
                        CAM_DEBUG(periph->path, CAM_DEBUG_INFO,
                            ("DV: period 0x%x\n", spi->sync_period));
                        kprintf("setting period to 0x%x\n", spi->sync_period);
                }
                cts->ccb_h.func_code = XPT_SET_TRAN_SETTINGS;
                cts->type = CTS_TYPE_CURRENT_SETTINGS;
                xpt_action((union ccb *)cts);
                if ((cts->ccb_h.status & CAM_STATUS_MASK) == CAM_REQ_CMP) {
                        break;
                }
                CAM_DEBUG(periph->path, CAM_DEBUG_INFO,
                    ("DV: failed to set period 0x%x\n", spi->sync_period));
                if (spi->sync_period == 0)
                        goto done;
        }
        result = 1;
done:
        xpt_free_ccb(&cts->ccb_h);

        return result;
}

static void
probedone(struct cam_periph *periph, union ccb *done_ccb)
{
        probe_softc *softc;
        struct cam_path *path;
        u_int32_t  priority;

        CAM_DEBUG(done_ccb->ccb_h.path, CAM_DEBUG_TRACE, ("probedone\n"));

        softc = (probe_softc *)periph->softc;
        path = done_ccb->ccb_h.path;
        priority = done_ccb->ccb_h.pinfo.priority;

        switch (softc->action) {
        case PROBE_TUR:
        {
                if ((done_ccb->ccb_h.status & CAM_STATUS_MASK) != CAM_REQ_CMP) {

                        if (cam_periph_error(done_ccb, 0,
                                             SF_NO_PRINT, NULL) == ERESTART)
                                return;
                        else if ((done_ccb->ccb_h.status & CAM_DEV_QFRZN) != 0)
                                /* Don't wedge the queue */
                                xpt_release_devq(done_ccb->ccb_h.path,
                                                 /*count*/1,
                                                 /*run_queue*/TRUE);
                }
                PROBE_SET_ACTION(softc, PROBE_INQUIRY);
                xpt_release_ccb(done_ccb);
                xpt_schedule(periph, priority);
                return;
        }
        case PROBE_INQUIRY:
        case PROBE_FULL_INQUIRY:
        {
                if ((done_ccb->ccb_h.status & CAM_STATUS_MASK) == CAM_REQ_CMP) {
                        struct scsi_inquiry_data *inq_buf;
                        u_int8_t periph_qual;

                        path->device->flags |= CAM_DEV_INQUIRY_DATA_VALID;
                        inq_buf = &path->device->inq_data;

                        periph_qual = SID_QUAL(inq_buf);

                        switch(periph_qual) {
                        case SID_QUAL_LU_CONNECTED:
                        {
                                u_int8_t len;

                                /*
                                 * We conservatively request only
                                 * SHORT_INQUIRY_LEN bytes of inquiry
                                 * information during our first try
                                 * at sending an INQUIRY. If the device
                                 * has more information to give,
                                 * perform a second request specifying
                                 * the amount of information the device
                                 * is willing to give.
                                 */
                                len = inq_buf->additional_length
                                    + offsetof(struct scsi_inquiry_data,
                                                additional_length) + 1;
                                if (softc->action == PROBE_INQUIRY
                                    && len > SHORT_INQUIRY_LENGTH) {
                                        PROBE_SET_ACTION(softc,
                                            PROBE_FULL_INQUIRY);
                                        xpt_release_ccb(done_ccb);
                                        xpt_schedule(periph, priority);
                                        return;
                                }

                                xpt_find_quirk(path->device);

                                xpt_devise_transport(path);
                                if (INQ_DATA_TQ_ENABLED(inq_buf))
                                        PROBE_SET_ACTION(softc, PROBE_MODE_SENSE);
                                else
                                        PROBE_SET_ACTION(softc, PROBE_SERIAL_NUM_0);

                                path->device->flags &= ~CAM_DEV_UNCONFIGURED;
                                xpt_reference_device(path->device);

                                xpt_release_ccb(done_ccb);
                                xpt_schedule(periph, priority);
                                return;
                        }
                        default:
                                break;
                        }
                } else if (cam_periph_error(done_ccb, 0,
                                            done_ccb->ccb_h.target_lun > 0
                                            ? SF_RETRY_UA|SF_QUIET_IR|SF_NO_PRINT
                                            : SF_RETRY_UA|SF_NO_PRINT,
                                            &softc->saved_ccb) == ERESTART) {
                        return;
                } else if ((done_ccb->ccb_h.status & CAM_DEV_QFRZN) != 0) {
                        /* Don't wedge the queue */
                        xpt_release_devq(done_ccb->ccb_h.path, /*count*/1,
                                         /*run_queue*/TRUE);
                }
                /*
                 * If we get to this point, we got an error status back
                 * from the inquiry and the error status doesn't require
                 * automatically retrying the command.  Therefore, the
                 * inquiry failed.  If we had inquiry information before
                 * for this device, but this latest inquiry command failed,
                 * the device has probably gone away.  If this device isn't
                 * already marked unconfigured, notify the peripheral
                 * drivers that this device is no more.
                 */
                if ((path->device->flags & CAM_DEV_UNCONFIGURED) == 0) {
                        /* Send the async notification. */
                        xpt_async(AC_LOST_DEVICE, path, NULL);
                }

                xpt_release_ccb(done_ccb);
                break;
        }
        case PROBE_MODE_SENSE:
        {
                struct ccb_scsiio *csio;
                struct scsi_mode_header_6 *mode_hdr;

                csio = &done_ccb->csio;
                mode_hdr = (struct scsi_mode_header_6 *)csio->data_ptr;
                if ((csio->ccb_h.status & CAM_STATUS_MASK) == CAM_REQ_CMP) {
                        struct scsi_control_page *page;
                        u_int8_t *offset;

                        offset = ((u_int8_t *)&mode_hdr[1])
                            + mode_hdr->blk_desc_len;
                        page = (struct scsi_control_page *)offset;
                        path->device->queue_flags = page->queue_flags;
                } else if (cam_periph_error(done_ccb, 0,
                                            SF_RETRY_UA|SF_NO_PRINT,
                                            &softc->saved_ccb) == ERESTART) {
                        return;
                } else if ((done_ccb->ccb_h.status & CAM_DEV_QFRZN) != 0) {
                        /* Don't wedge the queue */
                        xpt_release_devq(done_ccb->ccb_h.path,
                                         /*count*/1, /*run_queue*/TRUE);
                }
                xpt_release_ccb(done_ccb);
                kfree(mode_hdr, M_CAMXPT);
                PROBE_SET_ACTION(softc, PROBE_SERIAL_NUM_0);
                xpt_schedule(periph, priority);
                return;
        }
        case PROBE_SERIAL_NUM_0:
        {
                struct ccb_scsiio *csio;
                struct scsi_vpd_supported_page_list *page_list;
                int length, serialnum_supported, i;

                serialnum_supported = 0;
                csio = &done_ccb->csio;
                page_list =
                    (struct scsi_vpd_supported_page_list *)csio->data_ptr;

                if (page_list == NULL) {
                        /*
                         * Don't process the command as it was never sent
                         */
                } else if ((csio->ccb_h.status & CAM_STATUS_MASK) == CAM_REQ_CMP
                    && (page_list->length > 0)) {
                        length = min(page_list->length,
                            SVPD_SUPPORTED_PAGES_SIZE);
                        for (i = 0; i < length; i++) {
                                if (page_list->list[i] ==
                                    SVPD_UNIT_SERIAL_NUMBER) {
                                        serialnum_supported = 1;
                                        break;
                                }
                        }
                } else if (cam_periph_error(done_ccb, 0,
                                            SF_RETRY_UA|SF_NO_PRINT,
                                            &softc->saved_ccb) == ERESTART) {
                        return;
                } else if ((done_ccb->ccb_h.status & CAM_DEV_QFRZN) != 0) {
                        /* Don't wedge the queue */
                        xpt_release_devq(done_ccb->ccb_h.path, /*count*/1,
                                         /*run_queue*/TRUE);
                }

                if (page_list != NULL)
                        kfree(page_list, M_DEVBUF);

                if (serialnum_supported) {
                        xpt_release_ccb(done_ccb);
                        PROBE_SET_ACTION(softc, PROBE_SERIAL_NUM_1);
                        xpt_schedule(periph, priority);
                        return;
                }

                csio->data_ptr = NULL;
                /* FALLTHROUGH */
        }

        case PROBE_SERIAL_NUM_1:
        {
                struct ccb_scsiio *csio;
                struct scsi_vpd_unit_serial_number *serial_buf;
                u_int32_t  priority;
                int changed;
                int have_serialnum;

                changed = 1;
                have_serialnum = 0;
                csio = &done_ccb->csio;
                priority = done_ccb->ccb_h.pinfo.priority;
                serial_buf =
                    (struct scsi_vpd_unit_serial_number *)csio->data_ptr;

                /* Clean up from previous instance of this device */
                if (path->device->serial_num != NULL) {
                        kfree(path->device->serial_num, M_CAMXPT);
                        path->device->serial_num = NULL;
                        path->device->serial_num_len = 0;
                }

                if (serial_buf == NULL) {
                        /*
                         * Don't process the command as it was never sent
                         */
                } else if ((csio->ccb_h.status & CAM_STATUS_MASK) == CAM_REQ_CMP
                        && (serial_buf->length > 0)) {

                        have_serialnum = 1;
                        path->device->serial_num =
                                kmalloc((serial_buf->length + 1),
                                       M_CAMXPT, M_INTWAIT);
                        bcopy(serial_buf->serial_num,
                              path->device->serial_num,
                              serial_buf->length);
                        path->device->serial_num_len = serial_buf->length;
                        path->device->serial_num[serial_buf->length] = '\0';
                } else if (cam_periph_error(done_ccb, 0,
                                            SF_RETRY_UA|SF_NO_PRINT,
                                            &softc->saved_ccb) == ERESTART) {
                        return;
                } else if ((done_ccb->ccb_h.status & CAM_DEV_QFRZN) != 0) {
                        /* Don't wedge the queue */
                        xpt_release_devq(done_ccb->ccb_h.path, /*count*/1,
                                         /*run_queue*/TRUE);
                }

                /*
                 * Let's see if we have seen this device before.
                 */
                if ((softc->flags & PROBE_INQUIRY_CKSUM) != 0) {
                        MD5_CTX context;
                        u_int8_t digest[16];

                        MD5Init(&context);

                        MD5Update(&context,
                                  (unsigned char *)&path->device->inq_data,
                                  sizeof(struct scsi_inquiry_data));

                        if (have_serialnum)
                                MD5Update(&context, serial_buf->serial_num,
                                          serial_buf->length);

                        MD5Final(digest, &context);
                        if (bcmp(softc->digest, digest, 16) == 0)
                                changed = 0;

                        /*
                         * XXX Do we need to do a TUR in order to ensure
                         *     that the device really hasn't changed???
                         */
                        if ((changed != 0)
                         && ((softc->flags & PROBE_NO_ANNOUNCE) == 0))
                                xpt_async(AC_LOST_DEVICE, path, NULL);
                }
                if (serial_buf != NULL)
                        kfree(serial_buf, M_CAMXPT);

                if (changed != 0) {
                        /*
                         * Now that we have all the necessary
                         * information to safely perform transfer
                         * negotiations... Controllers don't perform
                         * any negotiation or tagged queuing until
                         * after the first XPT_SET_TRAN_SETTINGS ccb is
                         * received.  So, on a new device, just retrieve
                         * the user settings, and set them as the current
                         * settings to set the device up.
                         */
                        proberequestdefaultnegotiation(periph);
                        xpt_release_ccb(done_ccb);

                        /*
                         * Perform a TUR to allow the controller to
                         * perform any necessary transfer negotiation.
                         */
                        PROBE_SET_ACTION(softc, PROBE_TUR_FOR_NEGOTIATION);
                        xpt_schedule(periph, priority);
                        return;
                }
                xpt_release_ccb(done_ccb);
                break;
        }
        case PROBE_TUR_FOR_NEGOTIATION:
        case PROBE_DV_EXIT:
                if ((done_ccb->ccb_h.status & CAM_DEV_QFRZN) != 0) {
                        /* Don't wedge the queue */
                        xpt_release_devq(done_ccb->ccb_h.path, /*count*/1,
                                         /*run_queue*/TRUE);
                }

                xpt_reference_device(path->device);

                /*
                 * Do Domain Validation for lun 0 on devices that claim
                 * to support Synchronous Transfer modes.
                 *
                 * The SID_Sync flag is obsolete or misused in some
                 * situations (some virtio block devices), ignore it.
                 */
                if (softc->action == PROBE_TUR_FOR_NEGOTIATION
                 && done_ccb->ccb_h.target_lun == 0
                 /* && (path->device->inq_data.flags & SID_Sync) != 0 */
                 && (path->device->flags & CAM_DEV_IN_DV) == 0) {
                        CAM_DEBUG(periph->path, CAM_DEBUG_INFO,
                            ("Begin Domain Validation\n"));
                        path->device->flags |= CAM_DEV_IN_DV;
                        xpt_release_ccb(done_ccb);
                        PROBE_SET_ACTION(softc, PROBE_INQUIRY_BASIC_DV1);
                        xpt_schedule(periph, priority);
                        return;
                }
                if (softc->action == PROBE_DV_EXIT) {
                        CAM_DEBUG(periph->path, CAM_DEBUG_INFO,
                            ("Leave Domain Validation\n"));
                }
                path->device->flags &=
                    ~(CAM_DEV_UNCONFIGURED|CAM_DEV_IN_DV|CAM_DEV_DV_HIT_BOTTOM);
                if ((softc->flags & PROBE_NO_ANNOUNCE) == 0) {
                        /* Inform the XPT that a new device has been found */
                        done_ccb->ccb_h.func_code = XPT_GDEV_TYPE;
                        xpt_action(done_ccb);
                        xpt_async(AC_FOUND_DEVICE, done_ccb->ccb_h.path,
                                  done_ccb);
                }
                xpt_release_ccb(done_ccb);
                break;
        case PROBE_INQUIRY_BASIC_DV1:
        case PROBE_INQUIRY_BASIC_DV2:
        {
                struct scsi_inquiry_data *nbuf;
                struct ccb_scsiio *csio;

                if ((done_ccb->ccb_h.status & CAM_DEV_QFRZN) != 0) {
                        /* Don't wedge the queue */
                        xpt_release_devq(done_ccb->ccb_h.path, /*count*/1,
                                         /*run_queue*/TRUE);
                }
                csio = &done_ccb->csio;
                nbuf = (struct scsi_inquiry_data *)csio->data_ptr;
                if (bcmp(nbuf, &path->device->inq_data, SHORT_INQUIRY_LENGTH)) {
                        xpt_print(path,
                            "inquiry data fails comparison at DV%d step\n",
                            softc->action == PROBE_INQUIRY_BASIC_DV1 ? 1 : 2);
                        if (proberequestbackoff(periph, path->device)) {
                                path->device->flags &= ~CAM_DEV_IN_DV;
                                PROBE_SET_ACTION(softc, PROBE_TUR_FOR_NEGOTIATION);
                        } else {
                                /* give up */
                                PROBE_SET_ACTION(softc, PROBE_DV_EXIT);
                        }
                        kfree(nbuf, M_CAMXPT);
                        xpt_release_ccb(done_ccb);
                        xpt_schedule(periph, priority);
                        return;
                }
                kfree(nbuf, M_CAMXPT);
                if (softc->action == PROBE_INQUIRY_BASIC_DV1) {
                        PROBE_SET_ACTION(softc, PROBE_INQUIRY_BASIC_DV2);
                        xpt_release_ccb(done_ccb);
                        xpt_schedule(periph, priority);
                        return;
                }
                if (softc->action == PROBE_DV_EXIT) {
                        CAM_DEBUG(periph->path, CAM_DEBUG_INFO,
                            ("Leave Domain Validation Successfully\n"));
                }
                path->device->flags &=
                    ~(CAM_DEV_UNCONFIGURED|CAM_DEV_IN_DV|CAM_DEV_DV_HIT_BOTTOM);
                if ((softc->flags & PROBE_NO_ANNOUNCE) == 0) {
                        /* Inform the XPT that a new device has been found */
                        done_ccb->ccb_h.func_code = XPT_GDEV_TYPE;
                        xpt_action(done_ccb);
                        xpt_async(AC_FOUND_DEVICE, done_ccb->ccb_h.path,
                                  done_ccb);
                }
                xpt_release_ccb(done_ccb);
                break;
        }
        case PROBE_INVALID:
                CAM_DEBUG(done_ccb->ccb_h.path, CAM_DEBUG_INFO,
                    ("probedone: invalid action state\n"));
        default:
                break;
        }
        done_ccb = (union ccb *)TAILQ_FIRST(&softc->request_ccbs);
        TAILQ_REMOVE(&softc->request_ccbs, &done_ccb->ccb_h, periph_links.tqe);
        done_ccb->ccb_h.status = CAM_REQ_CMP;
        xpt_done(done_ccb);
        if (TAILQ_FIRST(&softc->request_ccbs) == NULL) {
                cam_periph_invalidate(periph);
                cam_periph_release(periph);
        } else {
                probeschedule(periph);
        }
}

static void
probecleanup(struct cam_periph *periph)
{
        kfree(periph->softc, M_CAMXPT);
}

static void
xpt_find_quirk(struct cam_ed *device)
{
        caddr_t match;

        match = cam_quirkmatch((caddr_t)&device->inq_data,
                               (caddr_t)xpt_quirk_table,
                               NELEM(xpt_quirk_table),
                               sizeof(*xpt_quirk_table), scsi_inquiry_match);

        if (match == NULL)
                panic("xpt_find_quirk: device didn't match wildcard entry!!");

        device->quirk = (struct xpt_quirk_entry *)match;
}

static int
sysctl_cam_search_luns(SYSCTL_HANDLER_ARGS)
{
        int error, lbool;

        lbool = cam_srch_hi;
        error = sysctl_handle_int(oidp, &lbool, 0, req);
        if (error != 0 || req->newptr == NULL)
                return (error);
        if (lbool == 0 || lbool == 1) {
                cam_srch_hi = lbool;
                return (0);
        } else {
                return (EINVAL);
        }
}

static void
xpt_devise_transport(struct cam_path *path)
{
        struct ccb_pathinq *cpi;
        struct ccb_trans_settings *cts;
        struct scsi_inquiry_data *inq_buf;

        /* Get transport information from the SIM */
        cpi = &xpt_alloc_ccb()->cpi;
        cts = &xpt_alloc_ccb()->cts;

        xpt_setup_ccb(&cpi->ccb_h, path, /*priority*/1);
        cpi->ccb_h.func_code = XPT_PATH_INQ;
        xpt_action((union ccb *)cpi);

        inq_buf = NULL;
        if ((path->device->flags & CAM_DEV_INQUIRY_DATA_VALID) != 0)
                inq_buf = &path->device->inq_data;
        path->device->protocol = PROTO_SCSI;
        path->device->protocol_version =
            inq_buf != NULL ? SID_ANSI_REV(inq_buf) : cpi->protocol_version;
        path->device->transport = cpi->transport;
        path->device->transport_version = cpi->transport_version;

        /*
         * Any device not using SPI3 features should
         * be considered SPI2 or lower.
         */
        if (inq_buf != NULL) {
                if (path->device->transport == XPORT_SPI
                 && (inq_buf->spi3data & SID_SPI_MASK) == 0
                 && path->device->transport_version > 2)
                        path->device->transport_version = 2;
        } else {
                struct cam_ed* otherdev;

                for (otherdev = TAILQ_FIRST(&path->target->ed_entries);
                     otherdev != NULL;
                     otherdev = TAILQ_NEXT(otherdev, links)) {
                        if (otherdev != path->device)
                                break;
                }

                if (otherdev != NULL) {
                        /*
                         * Initially assume the same versioning as
                         * prior luns for this target.
                         */
                        path->device->protocol_version =
                            otherdev->protocol_version;
                        path->device->transport_version =
                            otherdev->transport_version;
                } else {
                        /* Until we know better, opt for safty */
                        path->device->protocol_version = 2;
                        if (path->device->transport == XPORT_SPI)
                                path->device->transport_version = 2;
                        else
                                path->device->transport_version = 0;
                }
        }

        /*
         * XXX
         * For a device compliant with SPC-2 we should be able
         * to determine the transport version supported by
         * scrutinizing the version descriptors in the
         * inquiry buffer.
         */

        /* Tell the controller what we think */
        xpt_setup_ccb(&cts->ccb_h, path, /*priority*/1);
        cts->ccb_h.func_code = XPT_SET_TRAN_SETTINGS;
        cts->type = CTS_TYPE_CURRENT_SETTINGS;
        cts->transport = path->device->transport;
        cts->transport_version = path->device->transport_version;
        cts->protocol = path->device->protocol;
        cts->protocol_version = path->device->protocol_version;
        cts->proto_specific.valid = 0;
        cts->xport_specific.valid = 0;
        xpt_action((union ccb *)cts);

        xpt_free_ccb(&cts->ccb_h);
        xpt_free_ccb(&cpi->ccb_h);
}

static void
xpt_set_transfer_settings(struct ccb_trans_settings *cts, struct cam_ed *device,
                          int async_update)
{
        struct  ccb_pathinq *cpi;
        struct  ccb_trans_settings *cur_cts;
        struct  ccb_trans_settings_scsi *scsi;
        struct  ccb_trans_settings_scsi *cur_scsi;
        struct  cam_sim *sim;
        struct  scsi_inquiry_data *inq_data;

        if (device == NULL) {
                cts->ccb_h.status = CAM_PATH_INVALID;
                xpt_done((union ccb *)cts);
                return;
        }

        if (cts->protocol == PROTO_UNKNOWN
         || cts->protocol == PROTO_UNSPECIFIED) {
                cts->protocol = device->protocol;
                cts->protocol_version = device->protocol_version;
        }

        if (cts->protocol_version == PROTO_VERSION_UNKNOWN
         || cts->protocol_version == PROTO_VERSION_UNSPECIFIED)
                cts->protocol_version = device->protocol_version;

        if (cts->protocol != device->protocol) {
                xpt_print(cts->ccb_h.path, "Uninitialized Protocol %x:%x?\n",
                       cts->protocol, device->protocol);
                cts->protocol = device->protocol;
        }

        if (cts->protocol_version > device->protocol_version) {
                if (bootverbose) {
                        xpt_print(cts->ccb_h.path, "Down reving Protocol "
                            "Version from %d to %d?\n", cts->protocol_version,
                            device->protocol_version);
                }
                cts->protocol_version = device->protocol_version;
        }

        if (cts->transport == XPORT_UNKNOWN
         || cts->transport == XPORT_UNSPECIFIED) {
                cts->transport = device->transport;
                cts->transport_version = device->transport_version;
        }

        if (cts->transport_version == XPORT_VERSION_UNKNOWN
         || cts->transport_version == XPORT_VERSION_UNSPECIFIED)
                cts->transport_version = device->transport_version;

        if (cts->transport != device->transport) {
                xpt_print(cts->ccb_h.path, "Uninitialized Transport %x:%x?\n",
                    cts->transport, device->transport);
                cts->transport = device->transport;
        }

        if (cts->transport_version > device->transport_version) {
                if (bootverbose) {
                        xpt_print(cts->ccb_h.path, "Down reving Transport "
                            "Version from %d to %d?\n", cts->transport_version,
                            device->transport_version);
                }
                cts->transport_version = device->transport_version;
        }

        sim = cts->ccb_h.path->bus->sim;

        /*
         * Nothing more of interest to do unless
         * this is a device connected via the
         * SCSI protocol.
         */
        if (cts->protocol != PROTO_SCSI) {
                if (async_update == FALSE)
                        (*(sim->sim_action))(sim, (union ccb *)cts);
                return;
        }

        cpi = &xpt_alloc_ccb()->cpi;
        cur_cts = &xpt_alloc_ccb()->cts;

        inq_data = &device->inq_data;
        scsi = &cts->proto_specific.scsi;
        xpt_setup_ccb(&cpi->ccb_h, cts->ccb_h.path, /*priority*/1);
        cpi->ccb_h.func_code = XPT_PATH_INQ;
        xpt_action((union ccb *)cpi);

        /* SCSI specific sanity checking */
        if ((cpi->hba_inquiry & PI_TAG_ABLE) == 0
         || (INQ_DATA_TQ_ENABLED(inq_data)) == 0
         || (device->queue_flags & SCP_QUEUE_DQUE) != 0
         || (device->quirk->mintags == 0)) {
                /*
                 * Can't tag on hardware that doesn't support tags,
                 * doesn't have it enabled, or has broken tag support.
                 */
                scsi->flags &= ~CTS_SCSI_FLAGS_TAG_ENB;
        }

        if (async_update == FALSE) {
                /*
                 * Perform sanity checking against what the
                 * controller and device can do.
                 */
                xpt_setup_ccb(&cur_cts->ccb_h, cts->ccb_h.path, /*priority*/1);
                cur_cts->ccb_h.func_code = XPT_GET_TRAN_SETTINGS;
                cur_cts->type = cts->type;
                xpt_action((union ccb *)cur_cts);
                if ((cur_cts->ccb_h.status & CAM_STATUS_MASK) != CAM_REQ_CMP) {
                        goto done;
                }
                cur_scsi = &cur_cts->proto_specific.scsi;
                if ((scsi->valid & CTS_SCSI_VALID_TQ) == 0) {
                        scsi->flags &= ~CTS_SCSI_FLAGS_TAG_ENB;
                        scsi->flags |= cur_scsi->flags & CTS_SCSI_FLAGS_TAG_ENB;
                }
                if ((cur_scsi->valid & CTS_SCSI_VALID_TQ) == 0)
                        scsi->flags &= ~CTS_SCSI_FLAGS_TAG_ENB;
        }

        /* SPI specific sanity checking */
        if (cts->transport == XPORT_SPI && async_update == FALSE) {
                u_int spi3caps;
                struct ccb_trans_settings_spi *spi;
                struct ccb_trans_settings_spi *cur_spi;

                spi = &cts->xport_specific.spi;

                cur_spi = &cur_cts->xport_specific.spi;

                /* Fill in any gaps in what the user gave us */
                if ((spi->valid & CTS_SPI_VALID_SYNC_RATE) == 0)
                        spi->sync_period = cur_spi->sync_period;
                if ((cur_spi->valid & CTS_SPI_VALID_SYNC_RATE) == 0)
                        spi->sync_period = 0;
                if ((spi->valid & CTS_SPI_VALID_SYNC_OFFSET) == 0)
                        spi->sync_offset = cur_spi->sync_offset;
                if ((cur_spi->valid & CTS_SPI_VALID_SYNC_OFFSET) == 0)
                        spi->sync_offset = 0;
                if ((spi->valid & CTS_SPI_VALID_PPR_OPTIONS) == 0)
                        spi->ppr_options = cur_spi->ppr_options;
                if ((cur_spi->valid & CTS_SPI_VALID_PPR_OPTIONS) == 0)
                        spi->ppr_options = 0;
                if ((spi->valid & CTS_SPI_VALID_BUS_WIDTH) == 0)
                        spi->bus_width = cur_spi->bus_width;
                if ((cur_spi->valid & CTS_SPI_VALID_BUS_WIDTH) == 0)
                        spi->bus_width = 0;
                if ((spi->valid & CTS_SPI_VALID_DISC) == 0) {
                        spi->flags &= ~CTS_SPI_FLAGS_DISC_ENB;
                        spi->flags |= cur_spi->flags & CTS_SPI_FLAGS_DISC_ENB;
                }
                if ((cur_spi->valid & CTS_SPI_VALID_DISC) == 0)
                        spi->flags &= ~CTS_SPI_FLAGS_DISC_ENB;
                if (((device->flags & CAM_DEV_INQUIRY_DATA_VALID) != 0
                  && (inq_data->flags & SID_Sync) == 0
                  && cts->type == CTS_TYPE_CURRENT_SETTINGS)
                 || ((cpi->hba_inquiry & PI_SDTR_ABLE) == 0)) {
                        /* Force async */
                        spi->sync_period = 0;
                        spi->sync_offset = 0;
                }

                switch (spi->bus_width) {
                case MSG_EXT_WDTR_BUS_32_BIT:
                        if (((device->flags & CAM_DEV_INQUIRY_DATA_VALID) == 0
                          || (inq_data->flags & SID_WBus32) != 0
                          || cts->type == CTS_TYPE_USER_SETTINGS)
                         && (cpi->hba_inquiry & PI_WIDE_32) != 0)
                                break;
                        /* Fall Through to 16-bit */
                case MSG_EXT_WDTR_BUS_16_BIT:
                        if (((device->flags & CAM_DEV_INQUIRY_DATA_VALID) == 0
                          || (inq_data->flags & SID_WBus16) != 0
                          || cts->type == CTS_TYPE_USER_SETTINGS)
                         && (cpi->hba_inquiry & PI_WIDE_16) != 0) {
                                spi->bus_width = MSG_EXT_WDTR_BUS_16_BIT;
                                break;
                        }
                        /* Fall Through to 8-bit */
                default: /* New bus width?? */
                case MSG_EXT_WDTR_BUS_8_BIT:
                        /* All targets can do this */
                        spi->bus_width = MSG_EXT_WDTR_BUS_8_BIT;
                        break;
                }

                spi3caps = cpi->xport_specific.spi.ppr_options;
                if ((device->flags & CAM_DEV_INQUIRY_DATA_VALID) != 0
                 && cts->type == CTS_TYPE_CURRENT_SETTINGS)
                        spi3caps &= inq_data->spi3data;

                if ((spi3caps & SID_SPI_CLOCK_DT) == 0)
                        spi->ppr_options &= ~MSG_EXT_PPR_DT_REQ;

                if ((spi3caps & SID_SPI_IUS) == 0)
                        spi->ppr_options &= ~MSG_EXT_PPR_IU_REQ;

                if ((spi3caps & SID_SPI_QAS) == 0)
                        spi->ppr_options &= ~MSG_EXT_PPR_QAS_REQ;

                /* No SPI Transfer settings are allowed unless we are wide */
                if (spi->bus_width == 0)
                        spi->ppr_options = 0;

                if ((spi->valid & CTS_SPI_VALID_DISC)
                 && ((spi->flags & CTS_SPI_FLAGS_DISC_ENB) == 0)) {
                        /*
                         * Can't tag queue without disconnection.
                         */
                        scsi->flags &= ~CTS_SCSI_FLAGS_TAG_ENB;
                        scsi->valid |= CTS_SCSI_VALID_TQ;
                }

                /*
                 * If we are currently performing tagged transactions to
                 * this device and want to change its negotiation parameters,
                 * go non-tagged for a bit to give the controller a chance to
                 * negotiate unhampered by tag messages.
                 */
                if (cts->type == CTS_TYPE_CURRENT_SETTINGS
                 && (device->inq_flags & SID_CmdQue) != 0
                 && (scsi->flags & CTS_SCSI_FLAGS_TAG_ENB) != 0
                 && (spi->flags & (CTS_SPI_VALID_SYNC_RATE|
                                   CTS_SPI_VALID_SYNC_OFFSET|
                                   CTS_SPI_VALID_BUS_WIDTH)) != 0)
                        xpt_toggle_tags(cts->ccb_h.path);
        }

        if (cts->type == CTS_TYPE_CURRENT_SETTINGS
         && (scsi->valid & CTS_SCSI_VALID_TQ) != 0) {
                int device_tagenb;

                /*
                 * If we are transitioning from tags to no-tags or
                 * vice-versa, we need to carefully freeze and restart
                 * the queue so that we don't overlap tagged and non-tagged
                 * commands.  We also temporarily stop tags if there is
                 * a change in transfer negotiation settings to allow
                 * "tag-less" negotiation.
                 */
                if ((device->flags & CAM_DEV_TAG_AFTER_COUNT) != 0
                 || (device->inq_flags & SID_CmdQue) != 0)
                        device_tagenb = TRUE;
                else
                        device_tagenb = FALSE;

                if (((scsi->flags & CTS_SCSI_FLAGS_TAG_ENB) != 0
                  && device_tagenb == FALSE)
                 || ((scsi->flags & CTS_SCSI_FLAGS_TAG_ENB) == 0
                  && device_tagenb == TRUE)) {

                        if ((scsi->flags & CTS_SCSI_FLAGS_TAG_ENB) != 0) {
                                /*
                                 * Delay change to use tags until after a
                                 * few commands have gone to this device so
                                 * the controller has time to perform transfer
                                 * negotiations without tagged messages getting
                                 * in the way.
                                 */
                                device->tag_delay_count = CAM_TAG_DELAY_COUNT;
                                device->flags |= CAM_DEV_TAG_AFTER_COUNT;
                        } else {
                                struct ccb_relsim crs;

                                xpt_freeze_devq(cts->ccb_h.path, /*count*/1);
                                device->inq_flags &= ~SID_CmdQue;
                                xpt_dev_ccbq_resize(cts->ccb_h.path,
                                                    sim->max_dev_openings);
                                device->flags &= ~CAM_DEV_TAG_AFTER_COUNT;
                                device->tag_delay_count = 0;

                                xpt_setup_ccb(&crs.ccb_h, cts->ccb_h.path,
                                              /*priority*/1);
                                crs.ccb_h.func_code = XPT_REL_SIMQ;
                                crs.release_flags = RELSIM_RELEASE_AFTER_QEMPTY;
                                crs.openings
                                    = crs.release_timeout
                                    = crs.qfrozen_cnt
                                    = 0;
                                xpt_action((union ccb *)&crs);
                        }
                }
        }
        if (async_update == FALSE)
                (*(sim->sim_action))(sim, (union ccb *)cts);
done:
        xpt_free_ccb(&cur_cts->ccb_h);
        xpt_free_ccb(&cpi->ccb_h);
}

static void
xpt_toggle_tags(struct cam_path *path)
{
        struct cam_ed *dev;

        /*
         * Give controllers a chance to renegotiate
         * before starting tag operations.  We
         * "toggle" tagged queuing off then on
         * which causes the tag enable command delay
         * counter to come into effect.
         */
        dev = path->device;
        if ((dev->flags & CAM_DEV_TAG_AFTER_COUNT) != 0
         || ((dev->inq_flags & SID_CmdQue) != 0
          && (dev->inq_flags & (SID_Sync|SID_WBus16|SID_WBus32)) != 0)) {
                struct ccb_trans_settings *cts;

                cts = &xpt_alloc_ccb()->cts;
                xpt_setup_ccb(&cts->ccb_h, path, 1);
                cts->protocol = PROTO_SCSI;
                cts->protocol_version = PROTO_VERSION_UNSPECIFIED;
                cts->transport = XPORT_UNSPECIFIED;
                cts->transport_version = XPORT_VERSION_UNSPECIFIED;
                cts->proto_specific.scsi.flags = 0;
                cts->proto_specific.scsi.valid = CTS_SCSI_VALID_TQ;
                xpt_set_transfer_settings(cts, path->device,
                                          /*async_update*/TRUE);
                cts->proto_specific.scsi.flags = CTS_SCSI_FLAGS_TAG_ENB;
                xpt_set_transfer_settings(cts, path->device,
                                          /*async_update*/TRUE);
                xpt_free_ccb(&cts->ccb_h);
        }
}

static void
xpt_start_tags(struct cam_path *path)
{
        struct ccb_relsim *crs;
        struct cam_ed *device;
        struct cam_sim *sim;
        int    newopenings;

        crs = &xpt_alloc_ccb()->crs;
        device = path->device;
        sim = path->bus->sim;
        device->flags &= ~CAM_DEV_TAG_AFTER_COUNT;
        xpt_freeze_devq(path, /*count*/1);
        device->inq_flags |= SID_CmdQue;
        if (device->tag_saved_openings != 0)
                newopenings = device->tag_saved_openings;
        else
                newopenings = min(device->quirk->maxtags,
                                  sim->max_tagged_dev_openings);
        xpt_dev_ccbq_resize(path, newopenings);
        xpt_setup_ccb(&crs->ccb_h, path, /*priority*/1);
        crs->ccb_h.func_code = XPT_REL_SIMQ;
        crs->release_flags = RELSIM_RELEASE_AFTER_QEMPTY;
        crs->openings
            = crs->release_timeout
            = crs->qfrozen_cnt
            = 0;
        xpt_action((union ccb *)crs);
        xpt_free_ccb(&crs->ccb_h);
}

static int busses_to_config;
static int busses_to_reset;

static int
xptconfigbuscountfunc(struct cam_eb *bus, void *arg)
{
        sim_lock_assert_owned(bus->sim->lock);

        if (bus->counted_to_config == 0 && bus->path_id != CAM_XPT_PATH_ID) {
                struct cam_path path;
                struct ccb_pathinq *cpi;
                int can_negotiate;

                if (bootverbose) {
                        kprintf("CAM: Configuring bus:");
                        if (bus->sim) {
                                kprintf(" %s%d\n",
                                        bus->sim->sim_name,
                                        bus->sim->unit_number);
                        } else {
                                kprintf(" (unknown)\n");
                        }
                }

                cpi = &xpt_alloc_ccb()->cpi;

                atomic_add_int(&busses_to_config, 1);
                bus->counted_to_config = 1;
                xpt_compile_path(&path, NULL, bus->path_id,
                                 CAM_TARGET_WILDCARD, CAM_LUN_WILDCARD);
                xpt_setup_ccb(&cpi->ccb_h, &path, /*priority*/1);
                cpi->ccb_h.func_code = XPT_PATH_INQ;
                xpt_action((union ccb *)cpi);
                can_negotiate = cpi->hba_inquiry;
                can_negotiate &= (PI_WIDE_32|PI_WIDE_16|PI_SDTR_ABLE);
                if ((cpi->hba_misc & PIM_NOBUSRESET) == 0 && can_negotiate)
                        busses_to_reset++;
                xpt_release_path(&path);
                xpt_free_ccb(&cpi->ccb_h);
        } else
        if (bus->counted_to_config == 0 && bus->path_id == CAM_XPT_PATH_ID) {
                /* this is our dummy periph/bus */
                atomic_add_int(&busses_to_config, 1);
                bus->counted_to_config = 1;
        }

        return(1);
}

static int
xptconfigfunc(struct cam_eb *bus, void *arg)
{
        struct  cam_path *path;
        union   ccb *work_ccb;

        sim_lock_assert_owned(bus->sim->lock);

        if (bus->path_id != CAM_XPT_PATH_ID) {
                cam_status status;
                int can_negotiate;

                work_ccb = xpt_alloc_ccb();
                if ((status = xpt_create_path(&path, xpt_periph, bus->path_id,
                                              CAM_TARGET_WILDCARD,
                                              CAM_LUN_WILDCARD)) !=CAM_REQ_CMP){
                        kprintf("xptconfigfunc: xpt_create_path failed with "
                               "status %#x for bus %d\n", status, bus->path_id);
                        kprintf("xptconfigfunc: halting bus configuration\n");
                        xpt_free_ccb(&work_ccb->ccb_h);
                        xpt_uncount_bus(bus);
                        return(0);
                }
                xpt_setup_ccb(&work_ccb->ccb_h, path, /*priority*/1);
                work_ccb->ccb_h.func_code = XPT_PATH_INQ;
                xpt_action(work_ccb);
                if (work_ccb->ccb_h.status != CAM_REQ_CMP) {
                        kprintf("xptconfigfunc: CPI failed on bus %d "
                               "with status %d\n", bus->path_id,
                               work_ccb->ccb_h.status);
                        xpt_finishconfig(xpt_periph, work_ccb);
                        return(1);
                }

                can_negotiate = work_ccb->cpi.hba_inquiry;
                can_negotiate &= (PI_WIDE_32|PI_WIDE_16|PI_SDTR_ABLE);
                if ((work_ccb->cpi.hba_misc & PIM_NOBUSRESET) == 0
                 && (can_negotiate != 0)) {
                        xpt_setup_ccb(&work_ccb->ccb_h, path, /*priority*/1);
                        work_ccb->ccb_h.func_code = XPT_RESET_BUS;
                        work_ccb->ccb_h.cbfcnp = NULL;
                        CAM_DEBUG(path, CAM_DEBUG_SUBTRACE,
                                  ("Resetting Bus\n"));
                        xpt_action(work_ccb);
                        xpt_finishconfig(xpt_periph, work_ccb);
                } else {
                        /* Act as though we performed a successful BUS RESET */
                        work_ccb->ccb_h.func_code = XPT_RESET_BUS;
                        xpt_finishconfig(xpt_periph, work_ccb);
                }
        } else {
                xpt_uncount_bus(bus);
        }

        return(1);
}

/*
 * Now that interrupts are enabled, go find our devices.
 *
 * This hook function is called once by run_interrupt_driven_config_hooks().
 * XPT is expected to disestablish its hook when done.
 */
static void
xpt_config(void *arg)
{

#ifdef CAMDEBUG
        /* Setup debugging flags and path */
#ifdef CAM_DEBUG_FLAGS
        cam_dflags = CAM_DEBUG_FLAGS;
#else /* !CAM_DEBUG_FLAGS */
        cam_dflags = CAM_DEBUG_NONE;
#endif /* CAM_DEBUG_FLAGS */
#ifdef CAM_DEBUG_BUS
        if (cam_dflags != CAM_DEBUG_NONE) {
                /*
                 * Locking is specifically omitted here.  No SIMs have
                 * registered yet, so xpt_create_path will only be searching
                 * empty lists of targets and devices.
                 */
                if (xpt_create_path(&cam_dpath, xpt_periph,
                                    CAM_DEBUG_BUS, CAM_DEBUG_TARGET,
                                    CAM_DEBUG_LUN) != CAM_REQ_CMP) {
                        kprintf("xpt_config: xpt_create_path() failed for debug"
                               " target %d:%d:%d, debugging disabled\n",
                               CAM_DEBUG_BUS, CAM_DEBUG_TARGET, CAM_DEBUG_LUN);
                        cam_dflags = CAM_DEBUG_NONE;
                }
        } else {
                cam_dpath = NULL;
        }
#else /* !CAM_DEBUG_BUS */
        cam_dpath = NULL;
#endif /* CAM_DEBUG_BUS */
#endif /* CAMDEBUG */

        /*
         * Scan all installed busses.  This will also add a count
         * for our dummy placeholder (xpt_periph).
         */
        xpt_for_all_busses(xptconfigbuscountfunc, NULL);

        kprintf("CAM: Configuring %d busses\n", busses_to_config - 1);
        if (busses_to_reset > 0 && scsi_delay >= 2000) {
                kprintf("Waiting %d seconds for SCSI "
                        "devices to settle\n",
                        scsi_delay/1000);
        }
        xpt_for_all_busses(xptconfigfunc, NULL);
}

/*
 * If the given device only has one peripheral attached to it, and if that
 * peripheral is the passthrough driver, announce it.  This insures that the
 * user sees some sort of announcement for every peripheral in their system.
 */
static int
xptpassannouncefunc(struct cam_ed *device, void *arg)
{
        struct cam_periph *periph;
        int i;

        for (periph = SLIST_FIRST(&device->periphs), i = 0; periph != NULL;
             periph = SLIST_NEXT(periph, periph_links), i++);

        periph = SLIST_FIRST(&device->periphs);
        if ((i == 1)
         && (strncmp(periph->periph_name, "pass", 4) == 0))
                xpt_announce_periph(periph, NULL);

        return(1);
}

static void
xpt_finishconfig_task(void *context, int pending)
{
        struct  periph_driver **p_drv;
        int     i;

        kprintf("CAM: finished configuring all busses\n");

        if (busses_to_config == 0) {
                /* Register all the peripheral drivers */
                /* XXX This will have to change when we have loadable modules */
                p_drv = periph_drivers;
                for (i = 0; p_drv[i] != NULL; i++) {
                        (*p_drv[i]->init)();
                }

                /*
                 * Check for devices with no "standard" peripheral driver
                 * attached.  For any devices like that, announce the
                 * passthrough driver so the user will see something.
                 */
                xpt_for_all_devices(xptpassannouncefunc, NULL);

                /* Release our hook so that the boot can continue. */
                config_intrhook_disestablish(xsoftc.xpt_config_hook);
                kfree(xsoftc.xpt_config_hook, M_CAMXPT);
                xsoftc.xpt_config_hook = NULL;
        }
        kfree(context, M_CAMXPT);
}

static void
xpt_uncount_bus (struct cam_eb *bus)
{
        struct xpt_task *task;

        if (bus->counted_to_config) {
                bus->counted_to_config = 0;
                if (atomic_fetchadd_int(&busses_to_config, -1) == 1) {
                        task = kmalloc(sizeof(struct xpt_task), M_CAMXPT,
                                       M_INTWAIT | M_ZERO);
                        TASK_INIT(&task->task, 0, xpt_finishconfig_task, task);
                        taskqueue_enqueue(taskqueue_thread[mycpuid],
                                          &task->task);
                }
        }
}

static void
xpt_finishconfig(struct cam_periph *periph, union ccb *done_ccb)
{
        struct cam_path *path;

        path = done_ccb->ccb_h.path;
        CAM_DEBUG(path, CAM_DEBUG_TRACE, ("xpt_finishconfig\n"));

        switch(done_ccb->ccb_h.func_code) {
        case XPT_RESET_BUS:
                if (done_ccb->ccb_h.status == CAM_REQ_CMP) {
                        done_ccb->ccb_h.func_code = XPT_SCAN_BUS;
                        done_ccb->ccb_h.cbfcnp = xpt_finishconfig;
                        done_ccb->crcn.flags = 0;
                        xpt_action(done_ccb);
                        return;
                }
                /* FALLTHROUGH */
        case XPT_SCAN_BUS:
        default:
                if (bootverbose) {
                        kprintf("CAM: Finished configuring bus:");
                        if (path->bus->sim) {
                                kprintf(" %s%d\n",
                                        path->bus->sim->sim_name,
                                        path->bus->sim->unit_number);
                        } else {
                                kprintf(" (unknown)\n");
                        }
                }
                xpt_uncount_bus(path->bus);
                xpt_free_path(path);
                xpt_free_ccb(&done_ccb->ccb_h);
                break;
        }
}

cam_status
xpt_register_async(int event, ac_callback_t *cbfunc, void *cbarg,
                   struct cam_path *path)
{
        struct ccb_setasync *csa;
        cam_status status;
        int xptpath = 0;

        if (path == NULL) {
                lockmgr(&xsoftc.xpt_lock, LK_EXCLUSIVE);
                status = xpt_create_path(&path, /*periph*/NULL, CAM_XPT_PATH_ID,
                                         CAM_TARGET_WILDCARD, CAM_LUN_WILDCARD);
                if (status != CAM_REQ_CMP) {
                        lockmgr(&xsoftc.xpt_lock, LK_RELEASE);
                        return (status);
                }
                xptpath = 1;
        }

        csa = &xpt_alloc_ccb()->csa;
        xpt_setup_ccb(&csa->ccb_h, path, /*priority*/5);
        csa->ccb_h.func_code = XPT_SASYNC_CB;
        csa->event_enable = event;
        csa->callback = cbfunc;
        csa->callback_arg = cbarg;
        xpt_action((union ccb *)csa);
        status = csa->ccb_h.status;
        if (xptpath) {
                xpt_free_path(path);
                lockmgr(&xsoftc.xpt_lock, LK_RELEASE);
        }
        xpt_free_ccb(&csa->ccb_h);

        return (status);
}

static void
xptaction(struct cam_sim *sim, union ccb *work_ccb)
{
        CAM_DEBUG(work_ccb->ccb_h.path, CAM_DEBUG_TRACE, ("xptaction\n"));

        switch (work_ccb->ccb_h.func_code) {
        /* Common cases first */
        case XPT_PATH_INQ:              /* Path routing inquiry */
        {
                struct ccb_pathinq *cpi;

                cpi = &work_ccb->cpi;
                cpi->version_num = 1; /* XXX??? */
                cpi->hba_inquiry = 0;
                cpi->target_sprt = 0;
                cpi->hba_misc = 0;
                cpi->hba_eng_cnt = 0;
                cpi->max_target = 0;
                cpi->max_lun = 0;
                cpi->initiator_id = 0;
                strncpy(cpi->sim_vid, "FreeBSD", SIM_IDLEN);
                strncpy(cpi->hba_vid, "", HBA_IDLEN);
                strncpy(cpi->dev_name, sim->sim_name, DEV_IDLEN);
                cpi->unit_number = sim->unit_number;
                cpi->bus_id = sim->bus_id;
                cpi->base_transfer_speed = 0;
                cpi->protocol = PROTO_UNSPECIFIED;
                cpi->protocol_version = PROTO_VERSION_UNSPECIFIED;
                cpi->transport = XPORT_UNSPECIFIED;
                cpi->transport_version = XPORT_VERSION_UNSPECIFIED;
                cpi->ccb_h.status = CAM_REQ_CMP;
                xpt_done(work_ccb);
                break;
        }
        default:
                work_ccb->ccb_h.status = CAM_REQ_INVALID;
                xpt_done(work_ccb);
                break;
        }
}

/*
 * The xpt as a "controller" has no interrupt sources, so polling
 * is a no-op.
 */
static void
xptpoll(struct cam_sim *sim)
{
}

void
xpt_lock_buses(void)
{
        lockmgr(&xsoftc.xpt_topo_lock, LK_EXCLUSIVE);
}

void
xpt_unlock_buses(void)
{
        lockmgr(&xsoftc.xpt_topo_lock, LK_RELEASE);
}


/*
 * Should only be called by the machine interrupt dispatch routines,
 * so put these prototypes here instead of in the header.
 */

static void
swi_cambio(void *arg, void *frame)
{
        camisr(NULL);
}

static void
camisr(void *dummy)
{
        cam_simq_t queue;
        struct cam_sim *sim;

        spin_lock(&cam_simq_spin);
        TAILQ_INIT(&queue);
        TAILQ_CONCAT(&queue, &cam_simq, links);
        spin_unlock(&cam_simq_spin);

        while ((sim = TAILQ_FIRST(&queue)) != NULL) {
                TAILQ_REMOVE(&queue, sim, links);
                CAM_SIM_LOCK(sim);
                sim->flags &= ~CAM_SIM_ON_DONEQ;
                camisr_runqueue(sim);
                CAM_SIM_UNLOCK(sim);
        }
}

static void
camisr_runqueue(struct cam_sim *sim)
{
        struct  ccb_hdr *ccb_h;
        int     runq;

        spin_lock(&sim->sim_spin);
        while ((ccb_h = TAILQ_FIRST(&sim->sim_doneq)) != NULL) {
                TAILQ_REMOVE(&sim->sim_doneq, ccb_h, sim_links.tqe);
                spin_unlock(&sim->sim_spin);
                ccb_h->pinfo.index = CAM_UNQUEUED_INDEX;

                CAM_DEBUG(ccb_h->path, CAM_DEBUG_TRACE,
                          ("camisr\n"));

                runq = FALSE;

                if (ccb_h->flags & CAM_HIGH_POWER) {
                        struct highpowerlist    *hphead;
                        union ccb               *send_ccb;

                        lockmgr(&xsoftc.xpt_lock, LK_EXCLUSIVE);
                        hphead = &xsoftc.highpowerq;

                        send_ccb = (union ccb *)STAILQ_FIRST(hphead);

                        /*
                         * Increment the count since this command is done.
                         */
                        xsoftc.num_highpower++;

                        /*
                         * Any high powered commands queued up?
                         */
                        if (send_ccb != NULL) {
                                STAILQ_REMOVE_HEAD(hphead, xpt_links.stqe);
                                lockmgr(&xsoftc.xpt_lock, LK_RELEASE);

                                xpt_release_devq(send_ccb->ccb_h.path,
                                                 /*count*/1, /*runqueue*/TRUE);
                        } else
                                lockmgr(&xsoftc.xpt_lock, LK_RELEASE);
                }

                if ((ccb_h->func_code & XPT_FC_USER_CCB) == 0) {
                        struct cam_ed *dev;

                        dev = ccb_h->path->device;

                        cam_ccbq_ccb_done(&dev->ccbq, (union ccb *)ccb_h);

                        /*
                         * devq may be NULL if this is cam_dead_sim
                         */
                        if (ccb_h->path->bus->sim->devq) {
                                ccb_h->path->bus->sim->devq->send_active--;
                                ccb_h->path->bus->sim->devq->send_openings++;
                        }

                        if (((dev->flags & CAM_DEV_REL_ON_COMPLETE) != 0
                          && (ccb_h->status&CAM_STATUS_MASK) != CAM_REQUEUE_REQ)
                         || ((dev->flags & CAM_DEV_REL_ON_QUEUE_EMPTY) != 0
                          && (dev->ccbq.dev_active == 0))) {

                                xpt_release_devq(ccb_h->path, /*count*/1,
                                                 /*run_queue*/TRUE);
                        }

                        if ((dev->flags & CAM_DEV_TAG_AFTER_COUNT) != 0
                         && (--dev->tag_delay_count == 0))
                                xpt_start_tags(ccb_h->path);

                        if ((dev->ccbq.queue.entries > 0)
                         && (dev->qfrozen_cnt == 0)
                         && (device_is_send_queued(dev) == 0)) {
                                runq = xpt_schedule_dev_sendq(ccb_h->path->bus,
                                                              dev);
                        }
                }

                if (ccb_h->status & CAM_RELEASE_SIMQ) {
                        xpt_release_simq(ccb_h->path->bus->sim,
                                         /*run_queue*/TRUE);
                        ccb_h->status &= ~CAM_RELEASE_SIMQ;
                        runq = FALSE;
                }

                if ((ccb_h->flags & CAM_DEV_QFRZDIS)
                 && (ccb_h->status & CAM_DEV_QFRZN)) {
                        xpt_release_devq(ccb_h->path, /*count*/1,
                                         /*run_queue*/TRUE);
                        ccb_h->status &= ~CAM_DEV_QFRZN;
                } else if (runq) {
                        xpt_run_dev_sendq(ccb_h->path->bus);
                }

                /* Call the peripheral driver's callback */
                (*ccb_h->cbfcnp)(ccb_h->path->periph, (union ccb *)ccb_h);
                spin_lock(&sim->sim_spin);
        }
        spin_unlock(&sim->sim_spin);
}

/*
 * The dead_sim isn't completely hooked into CAM, we have to make sure
 * the doneq is cleared after calling xpt_done() so cam_periph_ccbwait()
 * doesn't block.
 */
static void
dead_sim_action(struct cam_sim *sim, union ccb *ccb)
{

        ccb->ccb_h.status = CAM_DEV_NOT_THERE;
        xpt_done(ccb);
        camisr_runqueue(sim);
}

static void
dead_sim_poll(struct cam_sim *sim)
{
}