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   1 /*
   2  *  hosts.c Copyright (C) 1992 Drew Eckhardt
   3  *          Copyright (C) 1993, 1994, 1995 Eric Youngdale
   4  *          Copyright (C) 2002-2003 Christoph Hellwig
   5  *
   6  *  mid to lowlevel SCSI driver interface
   7  *      Initial versions: Drew Eckhardt
   8  *      Subsequent revisions: Eric Youngdale
   9  *
  10  *  <drew@colorado.edu>
  11  *
  12  *  Jiffies wrap fixes (host->resetting), 3 Dec 1998 Andrea Arcangeli
  13  *  Added QLOGIC QLA1280 SCSI controller kernel host support.
  14  *     August 4, 1999 Fred Lewis, Intel DuPont
  15  *
  16  *  Updated to reflect the new initialization scheme for the higher
  17  *  level of scsi drivers (sd/sr/st)
  18  *  September 17, 2000 Torben Mathiasen <tmm@image.dk>
  19  *
  20  *  Restructured scsi_host lists and associated functions.
  21  *  September 04, 2002 Mike Anderson (andmike@us.ibm.com)
  22  */
  23
  24 #include <linux/module.h>
  25 #include <linux/blkdev.h>
  26 #include <linux/kernel.h>
  27 #include <linux/string.h>
  28 #include <linux/mm.h>
  29 #include <linux/init.h>
  30 #include <linux/completion.h>
  31 #include <linux/transport_class.h>
  32
  33 #include <scsi/scsi_device.h>
  34 #include <scsi/scsi_host.h>
  35 #include <scsi/scsi_transport.h>
  36
  37 #include "scsi_priv.h"
  38 #include "scsi_logging.h"
  39
  40
  41 static int scsi_host_next_hn;           /* host_no for next new host */
  42
  43
  44 static void scsi_host_cls_release(struct class_device *class_dev)
  45 {
  46         put_device(&class_to_shost(class_dev)->shost_gendev);
  47 }
  48
  49 static struct class shost_class = {
  50         .name           = "scsi_host",
  51         .release        = scsi_host_cls_release,
  52 };
  53
  54 /**
  55  *      scsi_host_set_state - Take the given host through the host
  56  *              state model.
  57  *      @shost: scsi host to change the state of.
  58  *      @state: state to change to.
  59  *
  60  *      Returns zero if unsuccessful or an error if the requested
  61  *      transition is illegal.
  62  **/
  63 int scsi_host_set_state(struct Scsi_Host *shost, enum scsi_host_state state)
  64 {
  65         enum scsi_host_state oldstate = shost->shost_state;
  66
  67         if (state == oldstate)
  68                 return 0;
  69
  70         switch (state) {
  71         case SHOST_CREATED:
  72                 /* There are no legal states that come back to
  73                  * created.  This is the manually initialised start
  74                  * state */
  75                 goto illegal;
  76
  77         case SHOST_RUNNING:
  78                 switch (oldstate) {
  79                 case SHOST_CREATED:
  80                 case SHOST_RECOVERY:
  81                         break;
  82                 default:
  83                         goto illegal;
  84                 }
  85                 break;
  86
  87         case SHOST_RECOVERY:
  88                 switch (oldstate) {
  89                 case SHOST_RUNNING:
  90                         break;
  91                 default:
  92                         goto illegal;
  93                 }
  94                 break;
  95
  96         case SHOST_CANCEL:
  97                 switch (oldstate) {
  98                 case SHOST_CREATED:
  99                 case SHOST_RUNNING:
 100                         break;
 101                 default:
 102                         goto illegal;
 103                 }
 104                 break;
 105
 106         case SHOST_DEL:
 107                 switch (oldstate) {
 108                 case SHOST_CANCEL:
 109                         break;
 110                 default:
 111                         goto illegal;
 112                 }
 113                 break;
 114
 115         }
 116         shost->shost_state = state;
 117         return 0;
 118
 119  illegal:
 120         SCSI_LOG_ERROR_RECOVERY(1,
 121                                 dev_printk(KERN_ERR, &shost->shost_gendev,
 122                                            "Illegal host state transition"
 123                                            "%s->%s\n",
 124                                            scsi_host_state_name(oldstate),
 125                                            scsi_host_state_name(state)));
 126         return -EINVAL;
 127 }
 128 EXPORT_SYMBOL(scsi_host_set_state);
 129
 130 /**
 131  * scsi_remove_host - remove a scsi host
 132  * @shost:      a pointer to a scsi host to remove
 133  **/
 134 void scsi_remove_host(struct Scsi_Host *shost)
 135 {
 136         down(&shost->scan_mutex);
 137         scsi_host_set_state(shost, SHOST_CANCEL);
 138         up(&shost->scan_mutex);
 139         scsi_forget_host(shost);
 140         scsi_proc_host_rm(shost);
 141
 142         scsi_host_set_state(shost, SHOST_DEL);
 143
 144         transport_unregister_device(&shost->shost_gendev);
 145         class_device_unregister(&shost->shost_classdev);
 146         device_del(&shost->shost_gendev);
 147 }
 148 EXPORT_SYMBOL(scsi_remove_host);
 149
 150 /**
 151  * scsi_add_host - add a scsi host
 152  * @shost:      scsi host pointer to add
 153  * @dev:        a struct device of type scsi class
 154  *
 155  * Return value:
 156  *      0 on success / != 0 for error
 157  **/
 158 int scsi_add_host(struct Scsi_Host *shost, struct device *dev)
 159 {
 160         struct scsi_host_template *sht = shost->hostt;
 161         int error = -EINVAL;
 162
 163         printk(KERN_INFO "scsi%d : %s\n", shost->host_no,
 164                         sht->info ? sht->info(shost) : sht->name);
 165
 166         if (!shost->can_queue) {
 167                 printk(KERN_ERR "%s: can_queue = 0 no longer supported\n",
 168                                 sht->name);
 169                 goto out;
 170         }
 171
 172         if (!shost->shost_gendev.parent)
 173                 shost->shost_gendev.parent = dev ? dev : &platform_bus;
 174
 175         error = device_add(&shost->shost_gendev);
 176         if (error)
 177                 goto out;
 178
 179         scsi_host_set_state(shost, SHOST_RUNNING);
 180         get_device(shost->shost_gendev.parent);
 181
 182         error = class_device_add(&shost->shost_classdev);
 183         if (error)
 184                 goto out_del_gendev;
 185
 186         get_device(&shost->shost_gendev);
 187
 188         if (shost->transportt->host_size &&
 189             (shost->shost_data = kmalloc(shost->transportt->host_size,
 190                                          GFP_KERNEL)) == NULL)
 191                 goto out_del_classdev;
 192
 193         if (shost->transportt->create_work_queue) {
 194                 snprintf(shost->work_q_name, KOBJ_NAME_LEN, "scsi_wq_%d",
 195                         shost->host_no);
 196                 shost->work_q = create_singlethread_workqueue(
 197                                         shost->work_q_name);
 198                 if (!shost->work_q)
 199                         goto out_free_shost_data;
 200         }
 201
 202         error = scsi_sysfs_add_host(shost);
 203         if (error)
 204                 goto out_destroy_host;
 205
 206         scsi_proc_host_add(shost);
 207         return error;
 208
 209  out_destroy_host:
 210         if (shost->work_q)
 211                 destroy_workqueue(shost->work_q);
 212  out_free_shost_data:
 213         kfree(shost->shost_data);
 214  out_del_classdev:
 215         class_device_del(&shost->shost_classdev);
 216  out_del_gendev:
 217         device_del(&shost->shost_gendev);
 218  out:
 219         return error;
 220 }
 221 EXPORT_SYMBOL(scsi_add_host);
 222
 223 static void scsi_host_dev_release(struct device *dev)
 224 {
 225         struct Scsi_Host *shost = dev_to_shost(dev);
 226         struct device *parent = dev->parent;
 227
 228         if (shost->ehandler) {
 229                 DECLARE_COMPLETION(sem);
 230                 shost->eh_notify = &sem;
 231                 shost->eh_kill = 1;
 232                 up(shost->eh_wait);
 233                 wait_for_completion(&sem);
 234                 shost->eh_notify = NULL;
 235         }
 236
 237         if (shost->work_q)
 238                 destroy_workqueue(shost->work_q);
 239
 240         scsi_proc_hostdir_rm(shost->hostt);
 241         scsi_destroy_command_freelist(shost);
 242         kfree(shost->shost_data);
 243
 244         if (parent)
 245                 put_device(parent);
 246         kfree(shost);
 247 }
 248
 249 /**
 250  * scsi_host_alloc - register a scsi host adapter instance.
 251  * @sht:        pointer to scsi host template
 252  * @privsize:   extra bytes to allocate for driver
 253  *
 254  * Note:
 255  *      Allocate a new Scsi_Host and perform basic initialization.
 256  *      The host is not published to the scsi midlayer until scsi_add_host
 257  *      is called.
 258  *
 259  * Return value:
 260  *      Pointer to a new Scsi_Host
 261  **/
 262 struct Scsi_Host *scsi_host_alloc(struct scsi_host_template *sht, int privsize)
 263 {
 264         struct Scsi_Host *shost;
 265         int gfp_mask = GFP_KERNEL, rval;
 266         DECLARE_COMPLETION(complete);
 267
 268         if (sht->unchecked_isa_dma && privsize)
 269                 gfp_mask |= __GFP_DMA;
 270
 271         /* Check to see if this host has any error handling facilities */
 272         if (!sht->eh_strategy_handler && !sht->eh_abort_handler &&
 273             !sht->eh_device_reset_handler && !sht->eh_bus_reset_handler &&
 274             !sht->eh_host_reset_handler) {
 275                 printk(KERN_ERR "ERROR: SCSI host `%s' has no error handling\n"
 276                                 "ERROR: This is not a safe way to run your "
 277                                         "SCSI host\n"
 278                                 "ERROR: The error handling must be added to "
 279                                 "this driver\n", sht->proc_name);
 280                 dump_stack();
 281         }
 282
 283         shost = kmalloc(sizeof(struct Scsi_Host) + privsize, gfp_mask);
 284         if (!shost)
 285                 return NULL;
 286         memset(shost, 0, sizeof(struct Scsi_Host) + privsize);
 287
 288         spin_lock_init(&shost->default_lock);
 289         scsi_assign_lock(shost, &shost->default_lock);
 290         shost->shost_state = SHOST_CREATED;
 291         INIT_LIST_HEAD(&shost->__devices);
 292         INIT_LIST_HEAD(&shost->__targets);
 293         INIT_LIST_HEAD(&shost->eh_cmd_q);
 294         INIT_LIST_HEAD(&shost->starved_list);
 295         init_waitqueue_head(&shost->host_wait);
 296
 297         init_MUTEX(&shost->scan_mutex);
 298
 299         shost->host_no = scsi_host_next_hn++; /* XXX(hch): still racy */
 300         shost->dma_channel = 0xff;
 301
 302         /* These three are default values which can be overridden */
 303         shost->max_channel = 0;
 304         shost->max_id = 8;
 305         shost->max_lun = 8;
 306
 307         /* Give each shost a default transportt */
 308         shost->transportt = &blank_transport_template;
 309
 310         /*
 311          * All drivers right now should be able to handle 12 byte
 312          * commands.  Every so often there are requests for 16 byte
 313          * commands, but individual low-level drivers need to certify that
 314          * they actually do something sensible with such commands.
 315          */
 316         shost->max_cmd_len = 12;
 317         shost->hostt = sht;
 318         shost->this_id = sht->this_id;
 319         shost->can_queue = sht->can_queue;
 320         shost->sg_tablesize = sht->sg_tablesize;
 321         shost->cmd_per_lun = sht->cmd_per_lun;
 322         shost->unchecked_isa_dma = sht->unchecked_isa_dma;
 323         shost->use_clustering = sht->use_clustering;
 324         shost->ordered_flush = sht->ordered_flush;
 325         shost->ordered_tag = sht->ordered_tag;
 326
 327         /*
 328          * hosts/devices that do queueing must support ordered tags
 329          */
 330         if (shost->can_queue > 1 && shost->ordered_flush) {
 331                 printk(KERN_ERR "scsi: ordered flushes don't support queueing\n");
 332                 shost->ordered_flush = 0;
 333         }
 334
 335         if (sht->max_host_blocked)
 336                 shost->max_host_blocked = sht->max_host_blocked;
 337         else
 338                 shost->max_host_blocked = SCSI_DEFAULT_HOST_BLOCKED;
 339
 340         /*
 341          * If the driver imposes no hard sector transfer limit, start at
 342          * machine infinity initially.
 343          */
 344         if (sht->max_sectors)
 345                 shost->max_sectors = sht->max_sectors;
 346         else
 347                 shost->max_sectors = SCSI_DEFAULT_MAX_SECTORS;
 348
 349         /*
 350          * assume a 4GB boundary, if not set
 351          */
 352         if (sht->dma_boundary)
 353                 shost->dma_boundary = sht->dma_boundary;
 354         else
 355                 shost->dma_boundary = 0xffffffff;
 356
 357         rval = scsi_setup_command_freelist(shost);
 358         if (rval)
 359                 goto fail_kfree;
 360
 361         device_initialize(&shost->shost_gendev);
 362         snprintf(shost->shost_gendev.bus_id, BUS_ID_SIZE, "host%d",
 363                 shost->host_no);
 364         shost->shost_gendev.release = scsi_host_dev_release;
 365
 366         class_device_initialize(&shost->shost_classdev);
 367         shost->shost_classdev.dev = &shost->shost_gendev;
 368         shost->shost_classdev.class = &shost_class;
 369         snprintf(shost->shost_classdev.class_id, BUS_ID_SIZE, "host%d",
 370                   shost->host_no);
 371
 372         shost->eh_notify = &complete;
 373         rval = kernel_thread(scsi_error_handler, shost, 0);
 374         if (rval < 0)
 375                 goto fail_destroy_freelist;
 376         wait_for_completion(&complete);
 377         shost->eh_notify = NULL;
 378
 379         scsi_proc_hostdir_add(shost->hostt);
 380         return shost;
 381
 382  fail_destroy_freelist:
 383         scsi_destroy_command_freelist(shost);
 384  fail_kfree:
 385         kfree(shost);
 386         return NULL;
 387 }
 388 EXPORT_SYMBOL(scsi_host_alloc);
 389
 390 struct Scsi_Host *scsi_register(struct scsi_host_template *sht, int privsize)
 391 {
 392         struct Scsi_Host *shost = scsi_host_alloc(sht, privsize);
 393
 394         if (!sht->detect) {
 395                 printk(KERN_WARNING "scsi_register() called on new-style "
 396                                     "template for driver %s\n", sht->name);
 397                 dump_stack();
 398         }
 399
 400         if (shost)
 401                 list_add_tail(&shost->sht_legacy_list, &sht->legacy_hosts);
 402         return shost;
 403 }
 404 EXPORT_SYMBOL(scsi_register);
 405
 406 void scsi_unregister(struct Scsi_Host *shost)
 407 {
 408         list_del(&shost->sht_legacy_list);
 409         scsi_host_put(shost);
 410 }
 411 EXPORT_SYMBOL(scsi_unregister);
 412
 413 /**
 414  * scsi_host_lookup - get a reference to a Scsi_Host by host no
 415  *
 416  * @hostnum:    host number to locate
 417  *
 418  * Return value:
 419  *      A pointer to located Scsi_Host or NULL.
 420  **/
 421 struct Scsi_Host *scsi_host_lookup(unsigned short hostnum)
 422 {
 423         struct class *class = &shost_class;
 424         struct class_device *cdev;
 425         struct Scsi_Host *shost = ERR_PTR(-ENXIO), *p;
 426
 427         down_read(&class->subsys.rwsem);
 428         list_for_each_entry(cdev, &class->children, node) {
 429                 p = class_to_shost(cdev);
 430                 if (p->host_no == hostnum) {
 431                         shost = scsi_host_get(p);
 432                         break;
 433                 }
 434         }
 435         up_read(&class->subsys.rwsem);
 436
 437         return shost;
 438 }
 439 EXPORT_SYMBOL(scsi_host_lookup);
 440
 441 /**
 442  * scsi_host_get - inc a Scsi_Host ref count
 443  * @shost:      Pointer to Scsi_Host to inc.
 444  **/
 445 struct Scsi_Host *scsi_host_get(struct Scsi_Host *shost)
 446 {
 447         if ((shost->shost_state == SHOST_DEL) ||
 448                 !get_device(&shost->shost_gendev))
 449                 return NULL;
 450         return shost;
 451 }
 452 EXPORT_SYMBOL(scsi_host_get);
 453
 454 /**
 455  * scsi_host_put - dec a Scsi_Host ref count
 456  * @shost:      Pointer to Scsi_Host to dec.
 457  **/
 458 void scsi_host_put(struct Scsi_Host *shost)
 459 {
 460         put_device(&shost->shost_gendev);
 461 }
 462 EXPORT_SYMBOL(scsi_host_put);
 463
 464 int scsi_init_hosts(void)
 465 {
 466         return class_register(&shost_class);
 467 }
 468
 469 void scsi_exit_hosts(void)
 470 {
 471         class_unregister(&shost_class);
 472 }
 473
 474 int scsi_is_host_device(const struct device *dev)
 475 {
 476         return dev->release == scsi_host_dev_release;
 477 }
 478 EXPORT_SYMBOL(scsi_is_host_device);
 479
 480 /**
 481  * scsi_queue_work - Queue work to the Scsi_Host workqueue.
 482  * @shost:      Pointer to Scsi_Host.
 483  * @work:       Work to queue for execution.
 484  *
 485  * Return value:
 486  *      0 on success / != 0 for error
 487  **/
 488 int scsi_queue_work(struct Scsi_Host *shost, struct work_struct *work)
 489 {
 490         if (unlikely(!shost->work_q)) {
 491                 printk(KERN_ERR
 492                         "ERROR: Scsi host '%s' attempted to queue scsi-work, "
 493                         "when no workqueue created.\n", shost->hostt->name);
 494                 dump_stack();
 495
 496                 return -EINVAL;
 497         }
 498
 499         return queue_work(shost->work_q, work);
 500 }
 501 EXPORT_SYMBOL_GPL(scsi_queue_work);
 502
 503 /**
 504  * scsi_flush_work - Flush a Scsi_Host's workqueue.
 505  * @shost:      Pointer to Scsi_Host.
 506  **/
 507 void scsi_flush_work(struct Scsi_Host *shost)
 508 {
 509         if (!shost->work_q) {
 510                 printk(KERN_ERR
 511                         "ERROR: Scsi host '%s' attempted to flush scsi-work, "
 512                         "when no workqueue created.\n", shost->hostt->name);
 513                 dump_stack();
 514                 return;
 515         }
 516
 517         flush_workqueue(shost->work_q);
 518 }
 519 EXPORT_SYMBOL_GPL(scsi_flush_work);