[SCSI] implement runtime Power Management
[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/slab.h>
28 #include <linux/kthread.h>
29 #include <linux/string.h>
30 #include <linux/mm.h>
31 #include <linux/init.h>
32 #include <linux/completion.h>
33 #include <linux/transport_class.h>
34 #include <linux/platform_device.h>
35 #include <linux/pm_runtime.h>
36
37 #include <scsi/scsi_device.h>
38 #include <scsi/scsi_host.h>
39 #include <scsi/scsi_transport.h>
40
41 #include "scsi_priv.h"
42 #include "scsi_logging.h"
43
44
45 static atomic_t scsi_host_next_hn;      /* host_no for next new host */
46
47
48 static void scsi_host_cls_release(struct device *dev)
49 {
50         put_device(&class_to_shost(dev)->shost_gendev);
51 }
52
53 static struct class shost_class = {
54         .name           = "scsi_host",
55         .dev_release    = scsi_host_cls_release,
56 };
57
58 /**
59  *      scsi_host_set_state - Take the given host through the host state model.
60  *      @shost: scsi host to change the state of.
61  *      @state: state to change to.
62  *
63  *      Returns zero if unsuccessful or an error if the requested
64  *      transition is illegal.
65  **/
66 int scsi_host_set_state(struct Scsi_Host *shost, enum scsi_host_state state)
67 {
68         enum scsi_host_state oldstate = shost->shost_state;
69
70         if (state == oldstate)
71                 return 0;
72
73         switch (state) {
74         case SHOST_CREATED:
75                 /* There are no legal states that come back to
76                  * created.  This is the manually initialised start
77                  * state */
78                 goto illegal;
79
80         case SHOST_RUNNING:
81                 switch (oldstate) {
82                 case SHOST_CREATED:
83                 case SHOST_RECOVERY:
84                         break;
85                 default:
86                         goto illegal;
87                 }
88                 break;
89
90         case SHOST_RECOVERY:
91                 switch (oldstate) {
92                 case SHOST_RUNNING:
93                         break;
94                 default:
95                         goto illegal;
96                 }
97                 break;
98
99         case SHOST_CANCEL:
100                 switch (oldstate) {
101                 case SHOST_CREATED:
102                 case SHOST_RUNNING:
103                 case SHOST_CANCEL_RECOVERY:
104                         break;
105                 default:
106                         goto illegal;
107                 }
108                 break;
109
110         case SHOST_DEL:
111                 switch (oldstate) {
112                 case SHOST_CANCEL:
113                 case SHOST_DEL_RECOVERY:
114                         break;
115                 default:
116                         goto illegal;
117                 }
118                 break;
119
120         case SHOST_CANCEL_RECOVERY:
121                 switch (oldstate) {
122                 case SHOST_CANCEL:
123                 case SHOST_RECOVERY:
124                         break;
125                 default:
126                         goto illegal;
127                 }
128                 break;
129
130         case SHOST_DEL_RECOVERY:
131                 switch (oldstate) {
132                 case SHOST_CANCEL_RECOVERY:
133                         break;
134                 default:
135                         goto illegal;
136                 }
137                 break;
138         }
139         shost->shost_state = state;
140         return 0;
141
142  illegal:
143         SCSI_LOG_ERROR_RECOVERY(1,
144                                 shost_printk(KERN_ERR, shost,
145                                              "Illegal host state transition"
146                                              "%s->%s\n",
147                                              scsi_host_state_name(oldstate),
148                                              scsi_host_state_name(state)));
149         return -EINVAL;
150 }
151 EXPORT_SYMBOL(scsi_host_set_state);
152
153 /**
154  * scsi_remove_host - remove a scsi host
155  * @shost:      a pointer to a scsi host to remove
156  **/
157 void scsi_remove_host(struct Scsi_Host *shost)
158 {
159         unsigned long flags;
160
161         mutex_lock(&shost->scan_mutex);
162         spin_lock_irqsave(shost->host_lock, flags);
163         if (scsi_host_set_state(shost, SHOST_CANCEL))
164                 if (scsi_host_set_state(shost, SHOST_CANCEL_RECOVERY)) {
165                         spin_unlock_irqrestore(shost->host_lock, flags);
166                         mutex_unlock(&shost->scan_mutex);
167                         return;
168                 }
169         spin_unlock_irqrestore(shost->host_lock, flags);
170
171         scsi_autopm_get_host(shost);
172         scsi_forget_host(shost);
173         mutex_unlock(&shost->scan_mutex);
174         scsi_proc_host_rm(shost);
175
176         spin_lock_irqsave(shost->host_lock, flags);
177         if (scsi_host_set_state(shost, SHOST_DEL))
178                 BUG_ON(scsi_host_set_state(shost, SHOST_DEL_RECOVERY));
179         spin_unlock_irqrestore(shost->host_lock, flags);
180
181         transport_unregister_device(&shost->shost_gendev);
182         device_unregister(&shost->shost_dev);
183         device_del(&shost->shost_gendev);
184 }
185 EXPORT_SYMBOL(scsi_remove_host);
186
187 /**
188  * scsi_add_host_with_dma - add a scsi host with dma device
189  * @shost:      scsi host pointer to add
190  * @dev:        a struct device of type scsi class
191  * @dma_dev:    dma device for the host
192  *
193  * Note: You rarely need to worry about this unless you're in a
194  * virtualised host environments, so use the simpler scsi_add_host()
195  * function instead.
196  *
197  * Return value: 
198  *      0 on success / != 0 for error
199  **/
200 int scsi_add_host_with_dma(struct Scsi_Host *shost, struct device *dev,
201                            struct device *dma_dev)
202 {
203         struct scsi_host_template *sht = shost->hostt;
204         int error = -EINVAL;
205
206         printk(KERN_INFO "scsi%d : %s\n", shost->host_no,
207                         sht->info ? sht->info(shost) : sht->name);
208
209         if (!shost->can_queue) {
210                 printk(KERN_ERR "%s: can_queue = 0 no longer supported\n",
211                                 sht->name);
212                 goto fail;
213         }
214
215         error = scsi_setup_command_freelist(shost);
216         if (error)
217                 goto fail;
218
219         if (!shost->shost_gendev.parent)
220                 shost->shost_gendev.parent = dev ? dev : &platform_bus;
221         shost->dma_dev = dma_dev;
222
223         error = device_add(&shost->shost_gendev);
224         if (error)
225                 goto out;
226
227         pm_runtime_set_active(&shost->shost_gendev);
228         pm_runtime_enable(&shost->shost_gendev);
229         device_enable_async_suspend(&shost->shost_gendev);
230
231         scsi_host_set_state(shost, SHOST_RUNNING);
232         get_device(shost->shost_gendev.parent);
233
234         device_enable_async_suspend(&shost->shost_dev);
235
236         error = device_add(&shost->shost_dev);
237         if (error)
238                 goto out_del_gendev;
239
240         get_device(&shost->shost_gendev);
241
242         if (shost->transportt->host_size) {
243                 shost->shost_data = kzalloc(shost->transportt->host_size,
244                                          GFP_KERNEL);
245                 if (shost->shost_data == NULL) {
246                         error = -ENOMEM;
247                         goto out_del_dev;
248                 }
249         }
250
251         if (shost->transportt->create_work_queue) {
252                 snprintf(shost->work_q_name, sizeof(shost->work_q_name),
253                          "scsi_wq_%d", shost->host_no);
254                 shost->work_q = create_singlethread_workqueue(
255                                         shost->work_q_name);
256                 if (!shost->work_q) {
257                         error = -EINVAL;
258                         goto out_free_shost_data;
259                 }
260         }
261
262         error = scsi_sysfs_add_host(shost);
263         if (error)
264                 goto out_destroy_host;
265
266         scsi_proc_host_add(shost);
267         return error;
268
269  out_destroy_host:
270         if (shost->work_q)
271                 destroy_workqueue(shost->work_q);
272  out_free_shost_data:
273         kfree(shost->shost_data);
274  out_del_dev:
275         device_del(&shost->shost_dev);
276  out_del_gendev:
277         device_del(&shost->shost_gendev);
278  out:
279         scsi_destroy_command_freelist(shost);
280  fail:
281         return error;
282 }
283 EXPORT_SYMBOL(scsi_add_host_with_dma);
284
285 static void scsi_host_dev_release(struct device *dev)
286 {
287         struct Scsi_Host *shost = dev_to_shost(dev);
288         struct device *parent = dev->parent;
289
290         scsi_proc_hostdir_rm(shost->hostt);
291
292         if (shost->ehandler)
293                 kthread_stop(shost->ehandler);
294         if (shost->work_q)
295                 destroy_workqueue(shost->work_q);
296         if (shost->uspace_req_q) {
297                 kfree(shost->uspace_req_q->queuedata);
298                 scsi_free_queue(shost->uspace_req_q);
299         }
300
301         scsi_destroy_command_freelist(shost);
302         if (shost->bqt)
303                 blk_free_tags(shost->bqt);
304
305         kfree(shost->shost_data);
306
307         if (parent)
308                 put_device(parent);
309         kfree(shost);
310 }
311
312 static struct device_type scsi_host_type = {
313         .name =         "scsi_host",
314         .release =      scsi_host_dev_release,
315 };
316
317 /**
318  * scsi_host_alloc - register a scsi host adapter instance.
319  * @sht:        pointer to scsi host template
320  * @privsize:   extra bytes to allocate for driver
321  *
322  * Note:
323  *      Allocate a new Scsi_Host and perform basic initialization.
324  *      The host is not published to the scsi midlayer until scsi_add_host
325  *      is called.
326  *
327  * Return value:
328  *      Pointer to a new Scsi_Host
329  **/
330 struct Scsi_Host *scsi_host_alloc(struct scsi_host_template *sht, int privsize)
331 {
332         struct Scsi_Host *shost;
333         gfp_t gfp_mask = GFP_KERNEL;
334
335         if (sht->unchecked_isa_dma && privsize)
336                 gfp_mask |= __GFP_DMA;
337
338         shost = kzalloc(sizeof(struct Scsi_Host) + privsize, gfp_mask);
339         if (!shost)
340                 return NULL;
341
342         shost->host_lock = &shost->default_lock;
343         spin_lock_init(shost->host_lock);
344         shost->shost_state = SHOST_CREATED;
345         INIT_LIST_HEAD(&shost->__devices);
346         INIT_LIST_HEAD(&shost->__targets);
347         INIT_LIST_HEAD(&shost->eh_cmd_q);
348         INIT_LIST_HEAD(&shost->starved_list);
349         init_waitqueue_head(&shost->host_wait);
350
351         mutex_init(&shost->scan_mutex);
352
353         /*
354          * subtract one because we increment first then return, but we need to
355          * know what the next host number was before increment
356          */
357         shost->host_no = atomic_inc_return(&scsi_host_next_hn) - 1;
358         shost->dma_channel = 0xff;
359
360         /* These three are default values which can be overridden */
361         shost->max_channel = 0;
362         shost->max_id = 8;
363         shost->max_lun = 8;
364
365         /* Give each shost a default transportt */
366         shost->transportt = &blank_transport_template;
367
368         /*
369          * All drivers right now should be able to handle 12 byte
370          * commands.  Every so often there are requests for 16 byte
371          * commands, but individual low-level drivers need to certify that
372          * they actually do something sensible with such commands.
373          */
374         shost->max_cmd_len = 12;
375         shost->hostt = sht;
376         shost->this_id = sht->this_id;
377         shost->can_queue = sht->can_queue;
378         shost->sg_tablesize = sht->sg_tablesize;
379         shost->cmd_per_lun = sht->cmd_per_lun;
380         shost->unchecked_isa_dma = sht->unchecked_isa_dma;
381         shost->use_clustering = sht->use_clustering;
382         shost->ordered_tag = sht->ordered_tag;
383
384         if (sht->supported_mode == MODE_UNKNOWN)
385                 /* means we didn't set it ... default to INITIATOR */
386                 shost->active_mode = MODE_INITIATOR;
387         else
388                 shost->active_mode = sht->supported_mode;
389
390         if (sht->max_host_blocked)
391                 shost->max_host_blocked = sht->max_host_blocked;
392         else
393                 shost->max_host_blocked = SCSI_DEFAULT_HOST_BLOCKED;
394
395         /*
396          * If the driver imposes no hard sector transfer limit, start at
397          * machine infinity initially.
398          */
399         if (sht->max_sectors)
400                 shost->max_sectors = sht->max_sectors;
401         else
402                 shost->max_sectors = SCSI_DEFAULT_MAX_SECTORS;
403
404         /*
405          * assume a 4GB boundary, if not set
406          */
407         if (sht->dma_boundary)
408                 shost->dma_boundary = sht->dma_boundary;
409         else
410                 shost->dma_boundary = 0xffffffff;
411
412         device_initialize(&shost->shost_gendev);
413         dev_set_name(&shost->shost_gendev, "host%d", shost->host_no);
414 #ifndef CONFIG_SYSFS_DEPRECATED
415         shost->shost_gendev.bus = &scsi_bus_type;
416 #endif
417         shost->shost_gendev.type = &scsi_host_type;
418
419         device_initialize(&shost->shost_dev);
420         shost->shost_dev.parent = &shost->shost_gendev;
421         shost->shost_dev.class = &shost_class;
422         dev_set_name(&shost->shost_dev, "host%d", shost->host_no);
423         shost->shost_dev.groups = scsi_sysfs_shost_attr_groups;
424
425         shost->ehandler = kthread_run(scsi_error_handler, shost,
426                         "scsi_eh_%d", shost->host_no);
427         if (IS_ERR(shost->ehandler)) {
428                 printk(KERN_WARNING "scsi%d: error handler thread failed to spawn, error = %ld\n",
429                         shost->host_no, PTR_ERR(shost->ehandler));
430                 goto fail_kfree;
431         }
432
433         scsi_proc_hostdir_add(shost->hostt);
434         return shost;
435
436  fail_kfree:
437         kfree(shost);
438         return NULL;
439 }
440 EXPORT_SYMBOL(scsi_host_alloc);
441
442 struct Scsi_Host *scsi_register(struct scsi_host_template *sht, int privsize)
443 {
444         struct Scsi_Host *shost = scsi_host_alloc(sht, privsize);
445
446         if (!sht->detect) {
447                 printk(KERN_WARNING "scsi_register() called on new-style "
448                                     "template for driver %s\n", sht->name);
449                 dump_stack();
450         }
451
452         if (shost)
453                 list_add_tail(&shost->sht_legacy_list, &sht->legacy_hosts);
454         return shost;
455 }
456 EXPORT_SYMBOL(scsi_register);
457
458 void scsi_unregister(struct Scsi_Host *shost)
459 {
460         list_del(&shost->sht_legacy_list);
461         scsi_host_put(shost);
462 }
463 EXPORT_SYMBOL(scsi_unregister);
464
465 static int __scsi_host_match(struct device *dev, void *data)
466 {
467         struct Scsi_Host *p;
468         unsigned short *hostnum = (unsigned short *)data;
469
470         p = class_to_shost(dev);
471         return p->host_no == *hostnum;
472 }
473
474 /**
475  * scsi_host_lookup - get a reference to a Scsi_Host by host no
476  * @hostnum:    host number to locate
477  *
478  * Return value:
479  *      A pointer to located Scsi_Host or NULL.
480  *
481  *      The caller must do a scsi_host_put() to drop the reference
482  *      that scsi_host_get() took. The put_device() below dropped
483  *      the reference from class_find_device().
484  **/
485 struct Scsi_Host *scsi_host_lookup(unsigned short hostnum)
486 {
487         struct device *cdev;
488         struct Scsi_Host *shost = NULL;
489
490         cdev = class_find_device(&shost_class, NULL, &hostnum,
491                                  __scsi_host_match);
492         if (cdev) {
493                 shost = scsi_host_get(class_to_shost(cdev));
494                 put_device(cdev);
495         }
496         return shost;
497 }
498 EXPORT_SYMBOL(scsi_host_lookup);
499
500 /**
501  * scsi_host_get - inc a Scsi_Host ref count
502  * @shost:      Pointer to Scsi_Host to inc.
503  **/
504 struct Scsi_Host *scsi_host_get(struct Scsi_Host *shost)
505 {
506         if ((shost->shost_state == SHOST_DEL) ||
507                 !get_device(&shost->shost_gendev))
508                 return NULL;
509         return shost;
510 }
511 EXPORT_SYMBOL(scsi_host_get);
512
513 /**
514  * scsi_host_put - dec a Scsi_Host ref count
515  * @shost:      Pointer to Scsi_Host to dec.
516  **/
517 void scsi_host_put(struct Scsi_Host *shost)
518 {
519         put_device(&shost->shost_gendev);
520 }
521 EXPORT_SYMBOL(scsi_host_put);
522
523 int scsi_init_hosts(void)
524 {
525         return class_register(&shost_class);
526 }
527
528 void scsi_exit_hosts(void)
529 {
530         class_unregister(&shost_class);
531 }
532
533 int scsi_is_host_device(const struct device *dev)
534 {
535         return dev->type == &scsi_host_type;
536 }
537 EXPORT_SYMBOL(scsi_is_host_device);
538
539 /**
540  * scsi_queue_work - Queue work to the Scsi_Host workqueue.
541  * @shost:      Pointer to Scsi_Host.
542  * @work:       Work to queue for execution.
543  *
544  * Return value:
545  *      1 - work queued for execution
546  *      0 - work is already queued
547  *      -EINVAL - work queue doesn't exist
548  **/
549 int scsi_queue_work(struct Scsi_Host *shost, struct work_struct *work)
550 {
551         if (unlikely(!shost->work_q)) {
552                 printk(KERN_ERR
553                         "ERROR: Scsi host '%s' attempted to queue scsi-work, "
554                         "when no workqueue created.\n", shost->hostt->name);
555                 dump_stack();
556
557                 return -EINVAL;
558         }
559
560         return queue_work(shost->work_q, work);
561 }
562 EXPORT_SYMBOL_GPL(scsi_queue_work);
563
564 /**
565  * scsi_flush_work - Flush a Scsi_Host's workqueue.
566  * @shost:      Pointer to Scsi_Host.
567  **/
568 void scsi_flush_work(struct Scsi_Host *shost)
569 {
570         if (!shost->work_q) {
571                 printk(KERN_ERR
572                         "ERROR: Scsi host '%s' attempted to flush scsi-work, "
573                         "when no workqueue created.\n", shost->hostt->name);
574                 dump_stack();
575                 return;
576         }
577
578         flush_workqueue(shost->work_q);
579 }
580 EXPORT_SYMBOL_GPL(scsi_flush_work);