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