63bed62f270e2d3fefd3a006239d3fead87f0515
[linux-2.6.git] / drivers / scsi / hosts.c
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/kthread.h>
28 #include <linux/string.h>
29 #include <linux/mm.h>
30 #include <linux/init.h>
31 #include <linux/completion.h>
32 #include <linux/transport_class.h>
33 #include <linux/platform_device.h>
34
35 #include <scsi/scsi_device.h>
36 #include <scsi/scsi_host.h>
37 #include <scsi/scsi_transport.h>
38
39 #include "scsi_priv.h"
40 #include "scsi_logging.h"
41
42
43 static int scsi_host_next_hn;           /* host_no for next new host */
44
45
46 static void scsi_host_cls_release(struct device *dev)
47 {
48         put_device(&class_to_shost(dev)->shost_gendev);
49 }
50
51 static struct class shost_class = {
52         .name           = "scsi_host",
53         .dev_release    = scsi_host_cls_release,
54 };
55
56 /**
57  *      scsi_host_set_state - Take the given host through the host state model.
58  *      @shost: scsi host to change the state of.
59  *      @state: state to change to.
60  *
61  *      Returns zero if unsuccessful or an error if the requested
62  *      transition is illegal.
63  **/
64 int scsi_host_set_state(struct Scsi_Host *shost, enum scsi_host_state state)
65 {
66         enum scsi_host_state oldstate = shost->shost_state;
67
68         if (state == oldstate)
69                 return 0;
70
71         switch (state) {
72         case SHOST_CREATED:
73                 /* There are no legal states that come back to
74                  * created.  This is the manually initialised start
75                  * state */
76                 goto illegal;
77
78         case SHOST_RUNNING:
79                 switch (oldstate) {
80                 case SHOST_CREATED:
81                 case SHOST_RECOVERY:
82                         break;
83                 default:
84                         goto illegal;
85                 }
86                 break;
87
88         case SHOST_RECOVERY:
89                 switch (oldstate) {
90                 case SHOST_RUNNING:
91                         break;
92                 default:
93                         goto illegal;
94                 }
95                 break;
96
97         case SHOST_CANCEL:
98                 switch (oldstate) {
99                 case SHOST_CREATED:
100                 case SHOST_RUNNING:
101                 case SHOST_CANCEL_RECOVERY:
102                         break;
103                 default:
104                         goto illegal;
105                 }
106                 break;
107
108         case SHOST_DEL:
109                 switch (oldstate) {
110                 case SHOST_CANCEL:
111                 case SHOST_DEL_RECOVERY:
112                         break;
113                 default:
114                         goto illegal;
115                 }
116                 break;
117
118         case SHOST_CANCEL_RECOVERY:
119                 switch (oldstate) {
120                 case SHOST_CANCEL:
121                 case SHOST_RECOVERY:
122                         break;
123                 default:
124                         goto illegal;
125                 }
126                 break;
127
128         case SHOST_DEL_RECOVERY:
129                 switch (oldstate) {
130                 case SHOST_CANCEL_RECOVERY:
131                         break;
132                 default:
133                         goto illegal;
134                 }
135                 break;
136         }
137         shost->shost_state = state;
138         return 0;
139
140  illegal:
141         SCSI_LOG_ERROR_RECOVERY(1,
142                                 shost_printk(KERN_ERR, shost,
143                                              "Illegal host state transition"
144                                              "%s->%s\n",
145                                              scsi_host_state_name(oldstate),
146                                              scsi_host_state_name(state)));
147         return -EINVAL;
148 }
149 EXPORT_SYMBOL(scsi_host_set_state);
150
151 /**
152  * scsi_remove_host - remove a scsi host
153  * @shost:      a pointer to a scsi host to remove
154  **/
155 void scsi_remove_host(struct Scsi_Host *shost)
156 {
157         unsigned long flags;
158         mutex_lock(&shost->scan_mutex);
159         spin_lock_irqsave(shost->host_lock, flags);
160         if (scsi_host_set_state(shost, SHOST_CANCEL))
161                 if (scsi_host_set_state(shost, SHOST_CANCEL_RECOVERY)) {
162                         spin_unlock_irqrestore(shost->host_lock, flags);
163                         mutex_unlock(&shost->scan_mutex);
164                         return;
165                 }
166         spin_unlock_irqrestore(shost->host_lock, flags);
167         mutex_unlock(&shost->scan_mutex);
168         scsi_forget_host(shost);
169         scsi_proc_host_rm(shost);
170
171         spin_lock_irqsave(shost->host_lock, flags);
172         if (scsi_host_set_state(shost, SHOST_DEL))
173                 BUG_ON(scsi_host_set_state(shost, SHOST_DEL_RECOVERY));
174         spin_unlock_irqrestore(shost->host_lock, flags);
175
176         transport_unregister_device(&shost->shost_gendev);
177         device_unregister(&shost->shost_dev);
178         device_del(&shost->shost_gendev);
179         scsi_proc_hostdir_rm(shost->hostt);
180 }
181 EXPORT_SYMBOL(scsi_remove_host);
182
183 /**
184  * scsi_add_host - add a scsi host
185  * @shost:      scsi host pointer to add
186  * @dev:        a struct device of type scsi class
187  *
188  * Return value: 
189  *      0 on success / != 0 for error
190  **/
191 int scsi_add_host(struct Scsi_Host *shost, struct device *dev)
192 {
193         struct scsi_host_template *sht = shost->hostt;
194         int error = -EINVAL;
195
196         printk(KERN_INFO "scsi%d : %s\n", shost->host_no,
197                         sht->info ? sht->info(shost) : sht->name);
198
199         if (!shost->can_queue) {
200                 printk(KERN_ERR "%s: can_queue = 0 no longer supported\n",
201                                 sht->name);
202                 goto out;
203         }
204
205         if (!shost->shost_gendev.parent)
206                 shost->shost_gendev.parent = dev ? dev : &platform_bus;
207
208         error = device_add(&shost->shost_gendev);
209         if (error)
210                 goto out;
211
212         scsi_host_set_state(shost, SHOST_RUNNING);
213         get_device(shost->shost_gendev.parent);
214
215         error = device_add(&shost->shost_dev);
216         if (error)
217                 goto out_del_gendev;
218
219         get_device(&shost->shost_gendev);
220
221         if (shost->transportt->host_size) {
222                 shost->shost_data = kzalloc(shost->transportt->host_size,
223                                          GFP_KERNEL);
224                 if (shost->shost_data == NULL) {
225                         error = -ENOMEM;
226                         goto out_del_dev;
227                 }
228         }
229
230         if (shost->transportt->create_work_queue) {
231                 snprintf(shost->work_q_name, KOBJ_NAME_LEN, "scsi_wq_%d",
232                         shost->host_no);
233                 shost->work_q = create_singlethread_workqueue(
234                                         shost->work_q_name);
235                 if (!shost->work_q) {
236                         error = -EINVAL;
237                         goto out_free_shost_data;
238                 }
239         }
240
241         error = scsi_sysfs_add_host(shost);
242         if (error)
243                 goto out_destroy_host;
244
245         scsi_proc_host_add(shost);
246         return error;
247
248  out_destroy_host:
249         if (shost->work_q)
250                 destroy_workqueue(shost->work_q);
251  out_free_shost_data:
252         kfree(shost->shost_data);
253  out_del_dev:
254         device_del(&shost->shost_dev);
255  out_del_gendev:
256         device_del(&shost->shost_gendev);
257  out:
258         return error;
259 }
260 EXPORT_SYMBOL(scsi_add_host);
261
262 static void scsi_host_dev_release(struct device *dev)
263 {
264         struct Scsi_Host *shost = dev_to_shost(dev);
265         struct device *parent = dev->parent;
266
267         if (shost->ehandler)
268                 kthread_stop(shost->ehandler);
269         if (shost->work_q)
270                 destroy_workqueue(shost->work_q);
271         if (shost->uspace_req_q) {
272                 kfree(shost->uspace_req_q->queuedata);
273                 scsi_free_queue(shost->uspace_req_q);
274         }
275
276         scsi_destroy_command_freelist(shost);
277         if (shost->bqt)
278                 blk_free_tags(shost->bqt);
279
280         kfree(shost->shost_data);
281
282         if (parent)
283                 put_device(parent);
284         kfree(shost);
285 }
286
287 struct device_type scsi_host_type = {
288         .name =         "scsi_host",
289         .release =      scsi_host_dev_release,
290 };
291
292 /**
293  * scsi_host_alloc - register a scsi host adapter instance.
294  * @sht:        pointer to scsi host template
295  * @privsize:   extra bytes to allocate for driver
296  *
297  * Note:
298  *      Allocate a new Scsi_Host and perform basic initialization.
299  *      The host is not published to the scsi midlayer until scsi_add_host
300  *      is called.
301  *
302  * Return value:
303  *      Pointer to a new Scsi_Host
304  **/
305 struct Scsi_Host *scsi_host_alloc(struct scsi_host_template *sht, int privsize)
306 {
307         struct Scsi_Host *shost;
308         gfp_t gfp_mask = GFP_KERNEL;
309         int rval;
310
311         if (sht->unchecked_isa_dma && privsize)
312                 gfp_mask |= __GFP_DMA;
313
314         shost = kzalloc(sizeof(struct Scsi_Host) + privsize, gfp_mask);
315         if (!shost)
316                 return NULL;
317
318         shost->host_lock = &shost->default_lock;
319         spin_lock_init(shost->host_lock);
320         shost->shost_state = SHOST_CREATED;
321         INIT_LIST_HEAD(&shost->__devices);
322         INIT_LIST_HEAD(&shost->__targets);
323         INIT_LIST_HEAD(&shost->eh_cmd_q);
324         INIT_LIST_HEAD(&shost->starved_list);
325         init_waitqueue_head(&shost->host_wait);
326
327         mutex_init(&shost->scan_mutex);
328
329         shost->host_no = scsi_host_next_hn++; /* XXX(hch): still racy */
330         shost->dma_channel = 0xff;
331
332         /* These three are default values which can be overridden */
333         shost->max_channel = 0;
334         shost->max_id = 8;
335         shost->max_lun = 8;
336
337         /* Give each shost a default transportt */
338         shost->transportt = &blank_transport_template;
339
340         /*
341          * All drivers right now should be able to handle 12 byte
342          * commands.  Every so often there are requests for 16 byte
343          * commands, but individual low-level drivers need to certify that
344          * they actually do something sensible with such commands.
345          */
346         shost->max_cmd_len = 12;
347         shost->hostt = sht;
348         shost->this_id = sht->this_id;
349         shost->can_queue = sht->can_queue;
350         shost->sg_tablesize = sht->sg_tablesize;
351         shost->cmd_per_lun = sht->cmd_per_lun;
352         shost->unchecked_isa_dma = sht->unchecked_isa_dma;
353         shost->use_clustering = sht->use_clustering;
354         shost->ordered_tag = sht->ordered_tag;
355
356         if (sht->supported_mode == MODE_UNKNOWN)
357                 /* means we didn't set it ... default to INITIATOR */
358                 shost->active_mode = MODE_INITIATOR;
359         else
360                 shost->active_mode = sht->supported_mode;
361
362         if (sht->max_host_blocked)
363                 shost->max_host_blocked = sht->max_host_blocked;
364         else
365                 shost->max_host_blocked = SCSI_DEFAULT_HOST_BLOCKED;
366
367         /*
368          * If the driver imposes no hard sector transfer limit, start at
369          * machine infinity initially.
370          */
371         if (sht->max_sectors)
372                 shost->max_sectors = sht->max_sectors;
373         else
374                 shost->max_sectors = SCSI_DEFAULT_MAX_SECTORS;
375
376         /*
377          * assume a 4GB boundary, if not set
378          */
379         if (sht->dma_boundary)
380                 shost->dma_boundary = sht->dma_boundary;
381         else
382                 shost->dma_boundary = 0xffffffff;
383
384         rval = scsi_setup_command_freelist(shost);
385         if (rval)
386                 goto fail_kfree;
387
388         device_initialize(&shost->shost_gendev);
389         snprintf(shost->shost_gendev.bus_id, BUS_ID_SIZE, "host%d",
390                 shost->host_no);
391 #ifndef CONFIG_SYSFS_DEPRECATED
392         shost->shost_gendev.bus = &scsi_bus_type;
393 #endif
394         shost->shost_gendev.type = &scsi_host_type;
395
396         device_initialize(&shost->shost_dev);
397         shost->shost_dev.parent = &shost->shost_gendev;
398         shost->shost_dev.class = &shost_class;
399         snprintf(shost->shost_dev.bus_id, BUS_ID_SIZE, "host%d",
400                  shost->host_no);
401
402         shost->ehandler = kthread_run(scsi_error_handler, shost,
403                         "scsi_eh_%d", shost->host_no);
404         if (IS_ERR(shost->ehandler)) {
405                 rval = PTR_ERR(shost->ehandler);
406                 goto fail_destroy_freelist;
407         }
408
409         scsi_proc_hostdir_add(shost->hostt);
410         return shost;
411
412  fail_destroy_freelist:
413         scsi_destroy_command_freelist(shost);
414  fail_kfree:
415         kfree(shost);
416         return NULL;
417 }
418 EXPORT_SYMBOL(scsi_host_alloc);
419
420 struct Scsi_Host *scsi_register(struct scsi_host_template *sht, int privsize)
421 {
422         struct Scsi_Host *shost = scsi_host_alloc(sht, privsize);
423
424         if (!sht->detect) {
425                 printk(KERN_WARNING "scsi_register() called on new-style "
426                                     "template for driver %s\n", sht->name);
427                 dump_stack();
428         }
429
430         if (shost)
431                 list_add_tail(&shost->sht_legacy_list, &sht->legacy_hosts);
432         return shost;
433 }
434 EXPORT_SYMBOL(scsi_register);
435
436 void scsi_unregister(struct Scsi_Host *shost)
437 {
438         list_del(&shost->sht_legacy_list);
439         scsi_host_put(shost);
440 }
441 EXPORT_SYMBOL(scsi_unregister);
442
443 static int __scsi_host_match(struct device *dev, void *data)
444 {
445         struct Scsi_Host *p;
446         unsigned short *hostnum = (unsigned short *)data;
447
448         p = class_to_shost(dev);
449         return p->host_no == *hostnum;
450 }
451
452 /**
453  * scsi_host_lookup - get a reference to a Scsi_Host by host no
454  * @hostnum:    host number to locate
455  *
456  * Return value:
457  *      A pointer to located Scsi_Host or NULL.
458  **/
459 struct Scsi_Host *scsi_host_lookup(unsigned short hostnum)
460 {
461         struct device *cdev;
462         struct Scsi_Host *shost = ERR_PTR(-ENXIO);
463
464         cdev = class_find_device(&shost_class, &hostnum, __scsi_host_match);
465         if (cdev)
466                 shost = scsi_host_get(class_to_shost(cdev));
467
468         return shost;
469 }
470 EXPORT_SYMBOL(scsi_host_lookup);
471
472 /**
473  * scsi_host_get - inc a Scsi_Host ref count
474  * @shost:      Pointer to Scsi_Host to inc.
475  **/
476 struct Scsi_Host *scsi_host_get(struct Scsi_Host *shost)
477 {
478         if ((shost->shost_state == SHOST_DEL) ||
479                 !get_device(&shost->shost_gendev))
480                 return NULL;
481         return shost;
482 }
483 EXPORT_SYMBOL(scsi_host_get);
484
485 /**
486  * scsi_host_put - dec a Scsi_Host ref count
487  * @shost:      Pointer to Scsi_Host to dec.
488  **/
489 void scsi_host_put(struct Scsi_Host *shost)
490 {
491         put_device(&shost->shost_gendev);
492 }
493 EXPORT_SYMBOL(scsi_host_put);
494
495 int scsi_init_hosts(void)
496 {
497         return class_register(&shost_class);
498 }
499
500 void scsi_exit_hosts(void)
501 {
502         class_unregister(&shost_class);
503 }
504
505 int scsi_is_host_device(const struct device *dev)
506 {
507         return dev->type == &scsi_host_type;
508 }
509 EXPORT_SYMBOL(scsi_is_host_device);
510
511 /**
512  * scsi_queue_work - Queue work to the Scsi_Host workqueue.
513  * @shost:      Pointer to Scsi_Host.
514  * @work:       Work to queue for execution.
515  *
516  * Return value:
517  *      1 - work queued for execution
518  *      0 - work is already queued
519  *      -EINVAL - work queue doesn't exist
520  **/
521 int scsi_queue_work(struct Scsi_Host *shost, struct work_struct *work)
522 {
523         if (unlikely(!shost->work_q)) {
524                 printk(KERN_ERR
525                         "ERROR: Scsi host '%s' attempted to queue scsi-work, "
526                         "when no workqueue created.\n", shost->hostt->name);
527                 dump_stack();
528
529                 return -EINVAL;
530         }
531
532         return queue_work(shost->work_q, work);
533 }
534 EXPORT_SYMBOL_GPL(scsi_queue_work);
535
536 /**
537  * scsi_flush_work - Flush a Scsi_Host's workqueue.
538  * @shost:      Pointer to Scsi_Host.
539  **/
540 void scsi_flush_work(struct Scsi_Host *shost)
541 {
542         if (!shost->work_q) {
543                 printk(KERN_ERR
544                         "ERROR: Scsi host '%s' attempted to flush scsi-work, "
545                         "when no workqueue created.\n", shost->hostt->name);
546                 dump_stack();
547                 return;
548         }
549
550         flush_workqueue(shost->work_q);
551 }
552 EXPORT_SYMBOL_GPL(scsi_flush_work);