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 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 class_device_unregister(&shost->shost_classdev);
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 = class_device_add(&shost->shost_classdev);
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_classdev;
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_classdev:
254 class_device_del(&shost->shost_classdev);
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 /**
288 * scsi_host_alloc - register a scsi host adapter instance.
289 * @sht: pointer to scsi host template
290 * @privsize: extra bytes to allocate for driver
291 *
292 * Note:
293 * Allocate a new Scsi_Host and perform basic initialization.
294 * The host is not published to the scsi midlayer until scsi_add_host
295 * is called.
296 *
297 * Return value:
298 * Pointer to a new Scsi_Host
299 **/
300 struct Scsi_Host *scsi_host_alloc(struct scsi_host_template *sht, int privsize)
301 {
302 struct Scsi_Host *shost;
303 gfp_t gfp_mask = GFP_KERNEL;
304 int rval;
305
306 if (sht->unchecked_isa_dma && privsize)
307 gfp_mask |= __GFP_DMA;
308
309 shost = kzalloc(sizeof(struct Scsi_Host) + privsize, gfp_mask);
310 if (!shost)
311 return NULL;
312
313 shost->host_lock = &shost->default_lock;
314 spin_lock_init(shost->host_lock);
315 shost->shost_state = SHOST_CREATED;
316 INIT_LIST_HEAD(&shost->__devices);
317 INIT_LIST_HEAD(&shost->__targets);
318 INIT_LIST_HEAD(&shost->eh_cmd_q);
319 INIT_LIST_HEAD(&shost->starved_list);
320 init_waitqueue_head(&shost->host_wait);
321
322 mutex_init(&shost->scan_mutex);
323
324 shost->host_no = scsi_host_next_hn++; /* XXX(hch): still racy */
325 shost->dma_channel = 0xff;
326
327 /* These three are default values which can be overridden */
328 shost->max_channel = 0;
329 shost->max_id = 8;
330 shost->max_lun = 8;
331
332 /* Give each shost a default transportt */
333 shost->transportt = &blank_transport_template;
334
335 /*
336 * All drivers right now should be able to handle 12 byte
337 * commands. Every so often there are requests for 16 byte
338 * commands, but individual low-level drivers need to certify that
339 * they actually do something sensible with such commands.
340 */
341 shost->max_cmd_len = 12;
342 shost->hostt = sht;
343 shost->this_id = sht->this_id;
344 shost->can_queue = sht->can_queue;
345 shost->sg_tablesize = sht->sg_tablesize;
346 shost->cmd_per_lun = sht->cmd_per_lun;
347 shost->unchecked_isa_dma = sht->unchecked_isa_dma;
348 shost->use_clustering = sht->use_clustering;
349 shost->ordered_tag = sht->ordered_tag;
350 shost->active_mode = sht->supported_mode;
351
352 if (sht->supported_mode == MODE_UNKNOWN)
353 /* means we didn't set it ... default to INITIATOR */
354 shost->active_mode = MODE_INITIATOR;
355 else
356 shost->active_mode = sht->supported_mode;
357
358 if (sht->max_host_blocked)
359 shost->max_host_blocked = sht->max_host_blocked;
360 else
361 shost->max_host_blocked = SCSI_DEFAULT_HOST_BLOCKED;
362
363 /*
364 * If the driver imposes no hard sector transfer limit, start at
365 * machine infinity initially.
366 */
367 if (sht->max_sectors)
368 shost->max_sectors = sht->max_sectors;
369 else
370 shost->max_sectors = SCSI_DEFAULT_MAX_SECTORS;
371
372 /*
373 * assume a 4GB boundary, if not set
374 */
375 if (sht->dma_boundary)
376 shost->dma_boundary = sht->dma_boundary;
377 else
378 shost->dma_boundary = 0xffffffff;
379
380 rval = scsi_setup_command_freelist(shost);
381 if (rval)
382 goto fail_kfree;
383
384 device_initialize(&shost->shost_gendev);
385 snprintf(shost->shost_gendev.bus_id, BUS_ID_SIZE, "host%d",
386 shost->host_no);
387 shost->shost_gendev.release = scsi_host_dev_release;
388
389 class_device_initialize(&shost->shost_classdev);
390 shost->shost_classdev.dev = &shost->shost_gendev;
391 shost->shost_classdev.class = &shost_class;
392 snprintf(shost->shost_classdev.class_id, BUS_ID_SIZE, "host%d",
393 shost->host_no);
394
395 shost->ehandler = kthread_run(scsi_error_handler, shost,
396 "scsi_eh_%d", shost->host_no);
397 if (IS_ERR(shost->ehandler)) {
398 rval = PTR_ERR(shost->ehandler);
399 goto fail_destroy_freelist;
400 }
401
402 scsi_proc_hostdir_add(shost->hostt);
403 return shost;
404
405 fail_destroy_freelist:
406 scsi_destroy_command_freelist(shost);
407 fail_kfree:
408 kfree(shost);
409 return NULL;
410 }
411 EXPORT_SYMBOL(scsi_host_alloc);
412
413 struct Scsi_Host *scsi_register(struct scsi_host_template *sht, int privsize)
414 {
415 struct Scsi_Host *shost = scsi_host_alloc(sht, privsize);
416
417 if (!sht->detect) {
418 printk(KERN_WARNING "scsi_register() called on new-style "
419 "template for driver %s\n", sht->name);
420 dump_stack();
421 }
422
423 if (shost)
424 list_add_tail(&shost->sht_legacy_list, &sht->legacy_hosts);
425 return shost;
426 }
427 EXPORT_SYMBOL(scsi_register);
428
429 void scsi_unregister(struct Scsi_Host *shost)
430 {
431 list_del(&shost->sht_legacy_list);
432 scsi_host_put(shost);
433 }
434 EXPORT_SYMBOL(scsi_unregister);
435
436 static int __scsi_host_match(struct class_device *cdev, void *data)
437 {
438 struct Scsi_Host *p;
439 unsigned short *hostnum = (unsigned short *)data;
440
441 p = class_to_shost(cdev);
442 return p->host_no == *hostnum;
443 }
444
445 /**
446 * scsi_host_lookup - get a reference to a Scsi_Host by host no
447 * @hostnum: host number to locate
448 *
449 * Return value:
450 * A pointer to located Scsi_Host or NULL.
451 **/
452 struct Scsi_Host *scsi_host_lookup(unsigned short hostnum)
453 {
454 struct class_device *cdev;
455 struct Scsi_Host *shost = ERR_PTR(-ENXIO);
456
457 cdev = class_find_child(&shost_class, &hostnum, __scsi_host_match);
458 if (cdev)
459 shost = scsi_host_get(class_to_shost(cdev));
460
461 return shost;
462 }
463 EXPORT_SYMBOL(scsi_host_lookup);
464
465 /**
466 * scsi_host_get - inc a Scsi_Host ref count
467 * @shost: Pointer to Scsi_Host to inc.
468 **/
469 struct Scsi_Host *scsi_host_get(struct Scsi_Host *shost)
470 {
471 if ((shost->shost_state == SHOST_DEL) ||
472 !get_device(&shost->shost_gendev))
473 return NULL;
474 return shost;
475 }
476 EXPORT_SYMBOL(scsi_host_get);
477
478 /**
479 * scsi_host_put - dec a Scsi_Host ref count
480 * @shost: Pointer to Scsi_Host to dec.
481 **/
482 void scsi_host_put(struct Scsi_Host *shost)
483 {
484 put_device(&shost->shost_gendev);
485 }
486 EXPORT_SYMBOL(scsi_host_put);
487
488 int scsi_init_hosts(void)
489 {
490 return class_register(&shost_class);
491 }
492
493 void scsi_exit_hosts(void)
494 {
495 class_unregister(&shost_class);
496 }
497
498 int scsi_is_host_device(const struct device *dev)
499 {
500 return dev->release == scsi_host_dev_release;
501 }
502 EXPORT_SYMBOL(scsi_is_host_device);
503
504 /**
505 * scsi_queue_work - Queue work to the Scsi_Host workqueue.
506 * @shost: Pointer to Scsi_Host.
507 * @work: Work to queue for execution.
508 *
509 * Return value:
510 * 1 - work queued for execution
511 * 0 - work is already queued
512 * -EINVAL - work queue doesn't exist
513 **/
514 int scsi_queue_work(struct Scsi_Host *shost, struct work_struct *work)
515 {
516 if (unlikely(!shost->work_q)) {
517 printk(KERN_ERR
518 "ERROR: Scsi host '%s' attempted to queue scsi-work, "
519 "when no workqueue created.\n", shost->hostt->name);
520 dump_stack();
521
522 return -EINVAL;
523 }
524
525 return queue_work(shost->work_q, work);
526 }
527 EXPORT_SYMBOL_GPL(scsi_queue_work);
528
529 /**
530 * scsi_flush_work - Flush a Scsi_Host's workqueue.
531 * @shost: Pointer to Scsi_Host.
532 **/
533 void scsi_flush_work(struct Scsi_Host *shost)
534 {
535 if (!shost->work_q) {
536 printk(KERN_ERR
537 "ERROR: Scsi host '%s' attempted to flush scsi-work, "
538 "when no workqueue created.\n", shost->hostt->name);
539 dump_stack();
540 return;
541 }
542
543 flush_workqueue(shost->work_q);
544 }
545 EXPORT_SYMBOL_GPL(scsi_flush_work);
546
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