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 1.13 2008/07/18 00:07:21 dillon Exp $
  30  */
  31
  32 #include <sys/param.h>
  33 #include <sys/systm.h>
  34 #include <sys/malloc.h>
  35 #include <sys/kernel.h>
  36 #include <sys/lock.h>
  37 #include <sys/spinlock.h>
  38 #include <sys/thread2.h>
  39 #include <sys/spinlock2.h>
  40
  41 #include "cam.h"
  42 #include "cam_ccb.h"
  43 #include "cam_sim.h"
  44 #include "cam_queue.h"
  45 #include "cam_xpt_sim.h"
  46
  47 #define CAM_PATH_ANY (u_int32_t)-1
  48
  49 MALLOC_DEFINE(M_CAMSIM, "CAM SIM", "CAM SIM buffers");
  50
  51 /* Drivers will use sim_mplock if they need the BGL */
  52 sim_lock        sim_mplock;
  53
  54 void
  55 cam_sim_lock(sim_lock *lock)
  56 {
  57         if (lock == &sim_mplock)
  58                 get_mplock();
  59         else
  60                 lockmgr(lock, LK_EXCLUSIVE);
  61 }
  62
  63 void
  64 cam_sim_unlock(sim_lock *lock)
  65 {
  66         if (lock == &sim_mplock)
  67                 rel_mplock();
  68         else
  69                 lockmgr(lock, LK_RELEASE);
  70 }
  71
  72 /*
  73  * lock can be NULL if sim was &dead_sim
  74  */
  75 void
  76 sim_lock_assert_owned(sim_lock *lock)
  77 {
  78         if (lock) {
  79                 if (lock == &sim_mplock)
  80                         ASSERT_MP_LOCK_HELD(curthread);
  81                 else
  82                         KKASSERT(lockstatus(lock, curthread) != 0);
  83         }
  84 }
  85
  86 void
  87 sim_lock_assert_unowned(sim_lock *lock)
  88 {
  89         if (lock) {
  90                 if (lock != &sim_mplock)
  91                         KKASSERT(lockstatus(lock, curthread) == 0);
  92         }
  93 }
  94
  95 int
  96 sim_lock_sleep(void *ident, int flags, const char *wmesg, int timo,
  97                sim_lock *lock)
  98 {
  99         int retval;
 100
 101         if (lock != &sim_mplock) {
 102                 /* lock should be held already */
 103                 KKASSERT(lockstatus(lock, curthread) != 0);
 104                 tsleep_interlock(ident, flags);
 105                 lockmgr(lock, LK_RELEASE);
 106                 retval = tsleep(ident, flags | PINTERLOCKED, wmesg, timo);
 107         } else {
 108                 retval = tsleep(ident, flags, wmesg, timo);
 109         }
 110
 111         if (lock != &sim_mplock) {
 112                 lockmgr(lock, LK_EXCLUSIVE);
 113         }
 114
 115         return (retval);
 116 }
 117
 118 struct cam_devq *
 119 cam_simq_alloc(u_int32_t max_sim_transactions)
 120 {
 121         return (cam_devq_alloc(/*size*/0, max_sim_transactions));
 122 }
 123
 124 void
 125 cam_simq_release(struct cam_devq *devq)
 126 {
 127         cam_devq_release(devq);
 128 }
 129
 130 /*
 131  * cam_sim_alloc() may potentially be called from an interrupt (?) but
 132  * unexpected things happen to the system if malloc() returns NULL so we
 133  * use M_INTWAIT anyway.
 134  */
 135 struct cam_sim *
 136 cam_sim_alloc(sim_action_func sim_action, sim_poll_func sim_poll,
 137               const char *sim_name, void *softc, u_int32_t unit,
 138               sim_lock *lock, int max_dev_transactions,
 139               int max_tagged_dev_transactions, struct cam_devq *queue)
 140 {
 141         struct cam_sim *sim;
 142
 143         /*
 144          * XXX ahd was limited to 256 instead of 512 for unknown reasons,
 145          * move that to a global limit here.  We may be able to remove this
 146          * code, needs testing.
 147          */
 148         if (max_dev_transactions > 256)
 149                 max_dev_transactions = 256;
 150         if (max_tagged_dev_transactions > 256)
 151                 max_tagged_dev_transactions = 256;
 152
 153         /*
 154          * Allocate a simq or use the supplied (possibly shared) simq.
 155          */
 156         if (queue == NULL)
 157                 queue = cam_simq_alloc(max_tagged_dev_transactions);
 158         else
 159                 cam_devq_reference(queue);
 160
 161         if (lock == NULL)
 162                 return (NULL);
 163
 164         sim = kmalloc(sizeof(struct cam_sim), M_CAMSIM, M_INTWAIT | M_ZERO);
 165         sim->sim_action = sim_action;
 166         sim->sim_poll = sim_poll;
 167         sim->sim_name = sim_name;
 168         sim->softc = softc;
 169         sim->path_id = CAM_PATH_ANY;
 170         sim->unit_number = unit;
 171         sim->bus_id = 0;        /* set in xpt_bus_register */
 172         sim->max_tagged_dev_openings = max_tagged_dev_transactions;
 173         sim->max_dev_openings = max_dev_transactions;
 174         sim->flags = 0;
 175         sim->refcount = 1;
 176         sim->devq = queue;
 177         sim->lock = lock;
 178         if (lock == &sim_mplock) {
 179                 sim->flags |= 0;
 180                 callout_init(&sim->callout);
 181         } else {
 182                 sim->flags |= CAM_SIM_MPSAFE;
 183                 callout_init_mp(&sim->callout);
 184         }
 185
 186         SLIST_INIT(&sim->ccb_freeq);
 187         TAILQ_INIT(&sim->sim_doneq);
 188         spin_init(&sim->sim_spin);
 189
 190         return (sim);
 191 }
 192
 193 static void deadsim_poll(struct cam_sim *sim);
 194 static void deadsim_action(struct cam_sim *sim, union ccb *ccb);
 195
 196 void
 197 cam_sim_free(struct cam_sim *sim)
 198 {
 199         sim->sim_action = deadsim_action;
 200         sim->sim_poll = deadsim_poll;
 201         cam_sim_release(sim, CAM_SIM_SOFTC);
 202 }
 203
 204 /*
 205  * Note: the devq is still used by individual peripherals even if the
 206  * backend sim disappears, so do not destroy it until the sim itself
 207  * is no longer needed.
 208  */
 209 void
 210 cam_sim_release(struct cam_sim *sim, int flags)
 211 {
 212         if (flags & CAM_SIM_SOFTC)
 213                 sim->softc = NULL;
 214         if (sim->refcount == 1) {
 215                 if (sim->devq) {
 216                         cam_simq_release(sim->devq);
 217                         sim->devq = NULL;
 218                 }
 219                 sim->refcount = 0;
 220                 kfree(sim, M_CAMSIM);
 221         } else {
 222                 --sim->refcount;
 223         }
 224 }
 225
 226 void
 227 cam_sim_set_path(struct cam_sim *sim, u_int32_t path_id)
 228 {
 229         sim->path_id = path_id;
 230 }
 231
 232 /*
 233  * Dead sim poll and action functions.  The backend to the sim has gone
 234  * away, aka usb, scsi device, etc... deal with it.
 235  */
 236 static void
 237 deadsim_poll(struct cam_sim *sim)
 238 {
 239         /* empty */
 240 }
 241
 242 static void
 243 deadsim_action(struct cam_sim *sim, union ccb *ccb)
 244 {
 245         ccb->ccb_h.status = CAM_TID_INVALID;
 246         xpt_done(ccb);
 247 }
 248