Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/sparc-2.6
[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 atomic_t 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         scsi_forget_host(shost);
168         mutex_unlock(&shost->scan_mutex);
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 }
180 EXPORT_SYMBOL(scsi_remove_host);
181
182 /**
183  * scsi_add_host_with_dma - add a scsi host with dma device
184  * @shost:      scsi host pointer to add
185  * @dev:        a struct device of type scsi class
186  * @dma_dev:    dma device for the host
187  *
188  * Note: You rarely need to worry about this unless you're in a
189  * virtualised host environments, so use the simpler scsi_add_host()
190  * function instead.
191  *
192  * Return value: 
193  *      0 on success / != 0 for error
194  **/
195 int scsi_add_host_with_dma(struct Scsi_Host *shost, struct device *dev,
196                            struct device *dma_dev)
197 {
198         struct scsi_host_template *sht = shost->hostt;
199         int error = -EINVAL;
200
201         printk(KERN_INFO "scsi%d : %s\n", shost->host_no,
202                         sht->info ? sht->info(shost) : sht->name);
203
204         if (!shost->can_queue) {
205                 printk(KERN_ERR "%s: can_queue = 0 no longer supported\n",
206                                 sht->name);
207                 goto fail;
208         }
209
210         error = scsi_setup_command_freelist(shost);
211         if (error)
212                 goto fail;
213
214         if (!shost->shost_gendev.parent)
215                 shost->shost_gendev.parent = dev ? dev : &platform_bus;
216         shost->dma_dev = dma_dev;
217
218         device_enable_async_suspend(&shost->shost_gendev);
219
220         error = device_add(&shost->shost_gendev);
221         if (error)
222                 goto out;
223
224         scsi_host_set_state(shost, SHOST_RUNNING);
225         get_device(shost->shost_gendev.parent);
226
227         device_enable_async_suspend(&shost->shost_dev);
228
229         error = device_add(&shost->shost_dev);
230         if (error)
231                 goto out_del_gendev;
232
233         get_device(&shost->shost_gendev);
234
235         if (shost->transportt->host_size) {
236                 shost->shost_data = kzalloc(shost->transportt->host_size,
237                                          GFP_KERNEL);
238                 if (shost->shost_data == NULL) {
239                         error = -ENOMEM;
240                         goto out_del_dev;
241                 }
242         }
243
244         if (shost->transportt->create_work_queue) {
245                 snprintf(shost->work_q_name, sizeof(shost->work_q_name),
246                          "scsi_wq_%d", shost->host_no);
247                 shost->work_q = create_singlethread_workqueue(
248                                         shost->work_q_name);
249                 if (!shost->work_q) {
250                         error = -EINVAL;
251                         goto out_free_shost_data;
252                 }
253         }
254
255         error = scsi_sysfs_add_host(shost);
256         if (error)
257                 goto out_destroy_host;
258
259         scsi_proc_host_add(shost);
260         return error;
261
262  out_destroy_host:
263         if (shost->work_q)
264                 destroy_workqueue(shost->work_q);
265  out_free_shost_data:
266         kfree(shost->shost_data);
267  out_del_dev:
268         device_del(&shost->shost_dev);
269  out_del_gendev:
270         device_del(&shost->shost_gendev);
271  out:
272         scsi_destroy_command_freelist(shost);
273  fail:
274         return error;
275 }
276 EXPORT_SYMBOL(scsi_add_host_with_dma);
277
278 static void scsi_host_dev_release(struct device *dev)
279 {
280         struct Scsi_Host *shost = dev_to_shost(dev);
281         struct device *parent = dev->parent;
282
283         scsi_proc_hostdir_rm(shost->hostt);
284
285         if (shost->ehandler)
286                 kthread_stop(shost->ehandler);
287         if (shost->work_q)
288                 destroy_workqueue(shost->work_q);
289         if (shost->uspace_req_q) {
290                 kfree(shost->uspace_req_q->queuedata);
291                 scsi_free_queue(shost->uspace_req_q);
292         }
293
294         scsi_destroy_command_freelist(shost);
295         if (shost->bqt)
296                 blk_free_tags(shost->bqt);
297
298         kfree(shost->shost_data);
299
300         if (parent)
301                 put_device(parent);
302         kfree(shost);
303 }
304
305 static struct device_type scsi_host_type = {
306         .name =         "scsi_host",
307         .release =      scsi_host_dev_release,
308 };
309
310 /**
311  * scsi_host_alloc - register a scsi host adapter instance.
312  * @sht:        pointer to scsi host template
313  * @privsize:   extra bytes to allocate for driver
314  *
315  * Note:
316  *      Allocate a new Scsi_Host and perform basic initialization.
317  *      The host is not published to the scsi midlayer until scsi_add_host
318  *      is called.
319  *
320  * Return value:
321  *      Pointer to a new Scsi_Host
322  **/
323 struct Scsi_Host *scsi_host_alloc(struct scsi_host_template *sht, int privsize)
324 {
325         struct Scsi_Host *shost;
326         gfp_t gfp_mask = GFP_KERNEL;
327         int rval;
328
329         if (sht->unchecked_isa_dma && privsize)
330                 gfp_mask |= __GFP_DMA;
331
332         shost = kzalloc(sizeof(struct Scsi_Host) + privsize, gfp_mask);
333         if (!shost)
334                 return NULL;
335
336         shost->host_lock = &shost->default_lock;
337         spin_lock_init(shost->host_lock);
338         shost->shost_state = SHOST_CREATED;
339         INIT_LIST_HEAD(&shost->__devices);
340         INIT_LIST_HEAD(&shost->__targets);
341         INIT_LIST_HEAD(&shost->eh_cmd_q);
342         INIT_LIST_HEAD(&shost->starved_list);
343         init_waitqueue_head(&shost->host_wait);
344
345         mutex_init(&shost->scan_mutex);
346
347         /*
348          * subtract one because we increment first then return, but we need to
349          * know what the next host number was before increment
350          */
351         shost->host_no = atomic_inc_return(&scsi_host_next_hn) - 1;
352         shost->dma_channel = 0xff;
353
354         /* These three are default values which can be overridden */
355         shost->max_channel = 0;
356         shost->max_id = 8;
357         shost->max_lun = 8;
358
359         /* Give each shost a default transportt */
360         shost->transportt = &blank_transport_template;
361
362         /*
363          * All drivers right now should be able to handle 12 byte
364          * commands.  Every so often there are requests for 16 byte
365          * commands, but individual low-level drivers need to certify that
366          * they actually do something sensible with such commands.
367          */
368         shost->max_cmd_len = 12;
369         shost->hostt = sht;
370         shost->this_id = sht->this_id;
371         shost->can_queue = sht->can_queue;
372         shost->sg_tablesize = sht->sg_tablesize;
373         shost->cmd_per_lun = sht->cmd_per_lun;
374         shost->unchecked_isa_dma = sht->unchecked_isa_dma;
375         shost->use_clustering = sht->use_clustering;
376         shost->ordered_tag = sht->ordered_tag;
377
378         if (sht->supported_mode == MODE_UNKNOWN)
379                 /* means we didn't set it ... default to INITIATOR */
380                 shost->active_mode = MODE_INITIATOR;
381         else
382                 shost->active_mode = sht->supported_mode;
383
384         if (sht->max_host_blocked)
385                 shost->max_host_blocked = sht->max_host_blocked;
386         else
387                 shost->max_host_blocked = SCSI_DEFAULT_HOST_BLOCKED;
388
389         /*
390          * If the driver imposes no hard sector transfer limit, start at
391          * machine infinity initially.
392          */
393         if (sht->max_sectors)
394                 shost->max_sectors = sht->max_sectors;
395         else
396                 shost->max_sectors = SCSI_DEFAULT_MAX_SECTORS;
397
398         /*
399          * assume a 4GB boundary, if not set
400          */
401         if (sht->dma_boundary)
402                 shost->dma_boundary = sht->dma_boundary;
403         else
404                 shost->dma_boundary = 0xffffffff;
405
406         device_initialize(&shost->shost_gendev);
407         dev_set_name(&shost->shost_gendev, "host%d", shost->host_no);
408 #ifndef CONFIG_SYSFS_DEPRECATED
409         shost->shost_gendev.bus = &scsi_bus_type;
410 #endif
411         shost->shost_gendev.type = &scsi_host_type;
412
413         device_initialize(&shost->shost_dev);
414         shost->shost_dev.parent = &shost->shost_gendev;
415         shost->shost_dev.class = &shost_class;
416         dev_set_name(&shost->shost_dev, "host%d", shost->host_no);
417         shost->shost_dev.groups = scsi_sysfs_shost_attr_groups;
418
419         shost->ehandler = kthread_run(scsi_error_handler, shost,
420                         "scsi_eh_%d", shost->host_no);
421         if (IS_ERR(shost->ehandler)) {
422                 rval = PTR_ERR(shost->ehandler);
423                 goto fail_kfree;
424         }
425
426         scsi_proc_hostdir_add(shost->hostt);
427         return shost;
428
429  fail_kfree:
430         kfree(shost);
431         return NULL;
432 }
433 EXPORT_SYMBOL(scsi_host_alloc);
434
435 struct Scsi_Host *scsi_register(struct scsi_host_template *sht, int privsize)
436 {
437         struct Scsi_Host *shost = scsi_host_alloc(sht, privsize);
438
439         if (!sht->detect) {
440                 printk(KERN_WARNING "scsi_register() called on new-style "
441                                     "template for driver %s\n", sht->name);
442                 dump_stack();
443         }
444
445         if (shost)
446                 list_add_tail(&shost->sht_legacy_list, &sht->legacy_hosts);
447         return shost;
448 }
449 EXPORT_SYMBOL(scsi_register);
450
451 void scsi_unregister(struct Scsi_Host *shost)
452 {
453         list_del(&shost->sht_legacy_list);
454         scsi_host_put(shost);
455 }
456 EXPORT_SYMBOL(scsi_unregister);
457
458 static int __scsi_host_match(struct device *dev, void *data)
459 {
460         struct Scsi_Host *p;
461         unsigned short *hostnum = (unsigned short *)data;
462
463         p = class_to_shost(dev);
464         return p->host_no == *hostnum;
465 }
466
467 /**
468  * scsi_host_lookup - get a reference to a Scsi_Host by host no
469  * @hostnum:    host number to locate
470  *
471  * Return value:
472  *      A pointer to located Scsi_Host or NULL.
473  *
474  *      The caller must do a scsi_host_put() to drop the reference
475  *      that scsi_host_get() took. The put_device() below dropped
476  *      the reference from class_find_device().
477  **/
478 struct Scsi_Host *scsi_host_lookup(unsigned short hostnum)
479 {
480         struct device *cdev;
481         struct Scsi_Host *shost = NULL;
482
483         cdev = class_find_device(&shost_class, NULL, &hostnum,
484                                  __scsi_host_match);
485         if (cdev) {
486                 shost = scsi_host_get(class_to_shost(cdev));
487                 put_device(cdev);
488         }
489         return shost;
490 }
491 EXPORT_SYMBOL(scsi_host_lookup);
492
493 /**
494  * scsi_host_get - inc a Scsi_Host ref count
495  * @shost:      Pointer to Scsi_Host to inc.
496  **/
497 struct Scsi_Host *scsi_host_get(struct Scsi_Host *shost)
498 {
499         if ((shost->shost_state == SHOST_DEL) ||
500                 !get_device(&shost->shost_gendev))
501                 return NULL;
502         return shost;
503 }
504 EXPORT_SYMBOL(scsi_host_get);
505
506 /**
507  * scsi_host_put - dec a Scsi_Host ref count
508  * @shost:      Pointer to Scsi_Host to dec.
509  **/
510 void scsi_host_put(struct Scsi_Host *shost)
511 {
512         put_device(&shost->shost_gendev);
513 }
514 EXPORT_SYMBOL(scsi_host_put);
515
516 int scsi_init_hosts(void)
517 {
518         return class_register(&shost_class);
519 }
520
521 void scsi_exit_hosts(void)
522 {
523         class_unregister(&shost_class);
524 }
525
526 int scsi_is_host_device(const struct device *dev)
527 {
528         return dev->type == &scsi_host_type;
529 }
530 EXPORT_SYMBOL(scsi_is_host_device);
531
532 /**
533  * scsi_queue_work - Queue work to the Scsi_Host workqueue.
534  * @shost:      Pointer to Scsi_Host.
535  * @work:       Work to queue for execution.
536  *
537  * Return value:
538  *      1 - work queued for execution
539  *      0 - work is already queued
540  *      -EINVAL - work queue doesn't exist
541  **/
542 int scsi_queue_work(struct Scsi_Host *shost, struct work_struct *work)
543 {
544         if (unlikely(!shost->work_q)) {
545                 printk(KERN_ERR
546                         "ERROR: Scsi host '%s' attempted to queue scsi-work, "
547                         "when no workqueue created.\n", shost->hostt->name);
548                 dump_stack();
549
550                 return -EINVAL;
551         }
552
553         return queue_work(shost->work_q, work);
554 }
555 EXPORT_SYMBOL_GPL(scsi_queue_work);
556
557 /**
558  * scsi_flush_work - Flush a Scsi_Host's workqueue.
559  * @shost:      Pointer to Scsi_Host.
560  **/
561 void scsi_flush_work(struct Scsi_Host *shost)
562 {
563         if (!shost->work_q) {
564                 printk(KERN_ERR
565                         "ERROR: Scsi host '%s' attempted to flush scsi-work, "
566                         "when no workqueue created.\n", shost->hostt->name);
567                 dump_stack();
568                 return;
569         }
570
571         flush_workqueue(shost->work_q);
572 }
573 EXPORT_SYMBOL_GPL(scsi_flush_work);