sys/bus/cam/cam_sim.c

   1 /*
   2  * Common functions for SCSI Interface Modules (SIMs).
   3  *
   4  * Copyright (c) 1997 Justin T. Gibbs.
   5  * All rights reserved.
   6  *
   7  * Redistribution and use in source and binary forms, with or without
   8  * modification, are permitted provided that the following conditions
   9  * are met:
  10  * 1. Redistributions of source code must retain the above copyright
  11  *    notice, this list of conditions, and the following disclaimer,
  12  *    without modification, immediately at the beginning of the file.
  13  * 2. The name of the author may not be used to endorse or promote products
  14  *    derived from this software without specific prior written permission.
  15  *
  16  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
  17  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  18  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  19  * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE FOR
  20  * ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  21  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  22  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  23  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  24  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  25  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  26  * SUCH DAMAGE.
  27  *
  28  * $FreeBSD: src/sys/cam/cam_sim.c,v 1.3 1999/08/28 00:40:42 peter Exp $
  29  * $DragonFly: src/sys/bus/cam/cam_sim.c,v 1.10 2007/12/01 22:21:17 pavalos Exp $
  30  */
  31
  32 #include <sys/param.h>
  33 #include <sys/systm.h>
  34 #include <sys/malloc.h>
  35 #include <sys/kernel.h>
  36
  37 #include "cam.h"
  38 #include "cam_ccb.h"
  39 #include "cam_sim.h"
  40 #include "cam_queue.h"
  41 #include "cam_xpt_sim.h"
  42
  43 #define CAM_PATH_ANY (u_int32_t)-1
  44
  45 MALLOC_DEFINE(M_CAMSIM, "CAM SIM", "CAM SIM buffers");
  46
  47 struct cam_devq *
  48 cam_simq_alloc(u_int32_t max_sim_transactions)
  49 {
  50         return (cam_devq_alloc(/*size*/0, max_sim_transactions));
  51 }
  52
  53 void
  54 cam_simq_release(struct cam_devq *devq)
  55 {
  56         cam_devq_release(devq);
  57 }
  58
  59 /*
  60  * cam_sim_alloc() may potentially be called from an interrupt (?) but
  61  * unexpected things happen to the system if malloc() returns NULL so we
  62  * use M_INTWAIT anyway.
  63  */
  64 struct cam_sim *
  65 cam_sim_alloc(sim_action_func sim_action, sim_poll_func sim_poll,
  66               const char *sim_name, void *softc, u_int32_t unit,
  67               int max_dev_transactions,
  68               int max_tagged_dev_transactions, struct cam_devq *queue)
  69 {
  70         struct cam_sim *sim;
  71
  72         /*
  73          * XXX ahd was limited to 256 instead of 512 for unknown reasons,
  74          * move that to a global limit here.  We may be able to remove this
  75          * code, needs testing.
  76          */
  77         if (max_dev_transactions > 256)
  78                 max_dev_transactions = 256;
  79         if (max_tagged_dev_transactions > 256)
  80                 max_tagged_dev_transactions = 256;
  81
  82         /*
  83          * Allocate a simq or use the supplied (possibly shared) simq.
  84          */
  85         if (queue == NULL)
  86                 queue = cam_simq_alloc(max_tagged_dev_transactions);
  87         else
  88                 cam_devq_reference(queue);
  89
  90         sim = kmalloc(sizeof(struct cam_sim), M_CAMSIM, M_INTWAIT | M_ZERO);
  91         sim->sim_action = sim_action;
  92         sim->sim_poll = sim_poll;
  93         sim->sim_name = sim_name;
  94         sim->softc = softc;
  95         sim->path_id = CAM_PATH_ANY;
  96         sim->unit_number = unit;
  97         sim->bus_id = 0;        /* set in xpt_bus_register */
  98         sim->max_tagged_dev_openings = max_tagged_dev_transactions;
  99         sim->max_dev_openings = max_dev_transactions;
 100         sim->flags = 0;
 101         sim->refcount = 1;
 102         callout_init(&sim->c_handle);
 103         sim->devq = queue;
 104
 105         return (sim);
 106 }
 107
 108 static void deadsim_poll(struct cam_sim *sim);
 109 static void deadsim_action(struct cam_sim *sim, union ccb *ccb);
 110
 111 void
 112 cam_sim_free(struct cam_sim *sim)
 113 {
 114         sim->sim_action = deadsim_action;
 115         sim->sim_poll = deadsim_poll;
 116         cam_sim_release(sim, CAM_SIM_SOFTC);
 117 }
 118
 119 /*
 120  * Note: the devq is still used by individual peripherals even if the
 121  * backend sim disappears, so do not destroy it until the sim itself
 122  * is no longer needed.
 123  */
 124 void
 125 cam_sim_release(struct cam_sim *sim, int flags)
 126 {
 127         if (flags & CAM_SIM_SOFTC)
 128                 sim->softc = NULL;
 129         if (sim->refcount == 1) {
 130                 if (sim->devq) {
 131                         cam_simq_release(sim->devq);
 132                         sim->devq = NULL;
 133                 }
 134                 sim->refcount = 0;
 135                 kfree(sim, M_CAMSIM);
 136         } else {
 137                 --sim->refcount;
 138         }
 139 }
 140
 141 void
 142 cam_sim_set_path(struct cam_sim *sim, u_int32_t path_id)
 143 {
 144         sim->path_id = path_id;
 145 }
 146
 147 /*
 148  * Dead sim poll and action functions.  The backend to the sim has gone
 149  * away, aka usb, scsi device, etc... deal with it.
 150  */
 151 static void
 152 deadsim_poll(struct cam_sim *sim)
 153 {
 154         /* empty */
 155 }
 156
 157 static void
 158 deadsim_action(struct cam_sim *sim, union ccb *ccb)
 159 {
 160         ccb->ccb_h.status = CAM_TID_INVALID;
 161         xpt_done(ccb);
 162 }
 163