xref: /openbmc/linux/drivers/scsi/hosts.c (revision 9d56dd3b083a3bec56e9da35ce07baca81030b03)
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 	error = device_add(&shost->shost_gendev);
219 	if (error)
220 		goto out;
221 
222 	scsi_host_set_state(shost, SHOST_RUNNING);
223 	get_device(shost->shost_gendev.parent);
224 
225 	error = device_add(&shost->shost_dev);
226 	if (error)
227 		goto out_del_gendev;
228 
229 	get_device(&shost->shost_gendev);
230 
231 	if (shost->transportt->host_size) {
232 		shost->shost_data = kzalloc(shost->transportt->host_size,
233 					 GFP_KERNEL);
234 		if (shost->shost_data == NULL) {
235 			error = -ENOMEM;
236 			goto out_del_dev;
237 		}
238 	}
239 
240 	if (shost->transportt->create_work_queue) {
241 		snprintf(shost->work_q_name, sizeof(shost->work_q_name),
242 			 "scsi_wq_%d", shost->host_no);
243 		shost->work_q = create_singlethread_workqueue(
244 					shost->work_q_name);
245 		if (!shost->work_q) {
246 			error = -EINVAL;
247 			goto out_free_shost_data;
248 		}
249 	}
250 
251 	error = scsi_sysfs_add_host(shost);
252 	if (error)
253 		goto out_destroy_host;
254 
255 	scsi_proc_host_add(shost);
256 	return error;
257 
258  out_destroy_host:
259 	if (shost->work_q)
260 		destroy_workqueue(shost->work_q);
261  out_free_shost_data:
262 	kfree(shost->shost_data);
263  out_del_dev:
264 	device_del(&shost->shost_dev);
265  out_del_gendev:
266 	device_del(&shost->shost_gendev);
267  out:
268 	scsi_destroy_command_freelist(shost);
269  fail:
270 	return error;
271 }
272 EXPORT_SYMBOL(scsi_add_host_with_dma);
273 
274 static void scsi_host_dev_release(struct device *dev)
275 {
276 	struct Scsi_Host *shost = dev_to_shost(dev);
277 	struct device *parent = dev->parent;
278 
279 	scsi_proc_hostdir_rm(shost->hostt);
280 
281 	if (shost->ehandler)
282 		kthread_stop(shost->ehandler);
283 	if (shost->work_q)
284 		destroy_workqueue(shost->work_q);
285 	if (shost->uspace_req_q) {
286 		kfree(shost->uspace_req_q->queuedata);
287 		scsi_free_queue(shost->uspace_req_q);
288 	}
289 
290 	scsi_destroy_command_freelist(shost);
291 	if (shost->bqt)
292 		blk_free_tags(shost->bqt);
293 
294 	kfree(shost->shost_data);
295 
296 	if (parent)
297 		put_device(parent);
298 	kfree(shost);
299 }
300 
301 static struct device_type scsi_host_type = {
302 	.name =		"scsi_host",
303 	.release =	scsi_host_dev_release,
304 };
305 
306 /**
307  * scsi_host_alloc - register a scsi host adapter instance.
308  * @sht:	pointer to scsi host template
309  * @privsize:	extra bytes to allocate for driver
310  *
311  * Note:
312  * 	Allocate a new Scsi_Host and perform basic initialization.
313  * 	The host is not published to the scsi midlayer until scsi_add_host
314  * 	is called.
315  *
316  * Return value:
317  * 	Pointer to a new Scsi_Host
318  **/
319 struct Scsi_Host *scsi_host_alloc(struct scsi_host_template *sht, int privsize)
320 {
321 	struct Scsi_Host *shost;
322 	gfp_t gfp_mask = GFP_KERNEL;
323 	int rval;
324 
325 	if (sht->unchecked_isa_dma && privsize)
326 		gfp_mask |= __GFP_DMA;
327 
328 	shost = kzalloc(sizeof(struct Scsi_Host) + privsize, gfp_mask);
329 	if (!shost)
330 		return NULL;
331 
332 	shost->host_lock = &shost->default_lock;
333 	spin_lock_init(shost->host_lock);
334 	shost->shost_state = SHOST_CREATED;
335 	INIT_LIST_HEAD(&shost->__devices);
336 	INIT_LIST_HEAD(&shost->__targets);
337 	INIT_LIST_HEAD(&shost->eh_cmd_q);
338 	INIT_LIST_HEAD(&shost->starved_list);
339 	init_waitqueue_head(&shost->host_wait);
340 
341 	mutex_init(&shost->scan_mutex);
342 
343 	/*
344 	 * subtract one because we increment first then return, but we need to
345 	 * know what the next host number was before increment
346 	 */
347 	shost->host_no = atomic_inc_return(&scsi_host_next_hn) - 1;
348 	shost->dma_channel = 0xff;
349 
350 	/* These three are default values which can be overridden */
351 	shost->max_channel = 0;
352 	shost->max_id = 8;
353 	shost->max_lun = 8;
354 
355 	/* Give each shost a default transportt */
356 	shost->transportt = &blank_transport_template;
357 
358 	/*
359 	 * All drivers right now should be able to handle 12 byte
360 	 * commands.  Every so often there are requests for 16 byte
361 	 * commands, but individual low-level drivers need to certify that
362 	 * they actually do something sensible with such commands.
363 	 */
364 	shost->max_cmd_len = 12;
365 	shost->hostt = sht;
366 	shost->this_id = sht->this_id;
367 	shost->can_queue = sht->can_queue;
368 	shost->sg_tablesize = sht->sg_tablesize;
369 	shost->cmd_per_lun = sht->cmd_per_lun;
370 	shost->unchecked_isa_dma = sht->unchecked_isa_dma;
371 	shost->use_clustering = sht->use_clustering;
372 	shost->ordered_tag = sht->ordered_tag;
373 
374 	if (sht->supported_mode == MODE_UNKNOWN)
375 		/* means we didn't set it ... default to INITIATOR */
376 		shost->active_mode = MODE_INITIATOR;
377 	else
378 		shost->active_mode = sht->supported_mode;
379 
380 	if (sht->max_host_blocked)
381 		shost->max_host_blocked = sht->max_host_blocked;
382 	else
383 		shost->max_host_blocked = SCSI_DEFAULT_HOST_BLOCKED;
384 
385 	/*
386 	 * If the driver imposes no hard sector transfer limit, start at
387 	 * machine infinity initially.
388 	 */
389 	if (sht->max_sectors)
390 		shost->max_sectors = sht->max_sectors;
391 	else
392 		shost->max_sectors = SCSI_DEFAULT_MAX_SECTORS;
393 
394 	/*
395 	 * assume a 4GB boundary, if not set
396 	 */
397 	if (sht->dma_boundary)
398 		shost->dma_boundary = sht->dma_boundary;
399 	else
400 		shost->dma_boundary = 0xffffffff;
401 
402 	device_initialize(&shost->shost_gendev);
403 	dev_set_name(&shost->shost_gendev, "host%d", shost->host_no);
404 #ifndef CONFIG_SYSFS_DEPRECATED
405 	shost->shost_gendev.bus = &scsi_bus_type;
406 #endif
407 	shost->shost_gendev.type = &scsi_host_type;
408 
409 	device_initialize(&shost->shost_dev);
410 	shost->shost_dev.parent = &shost->shost_gendev;
411 	shost->shost_dev.class = &shost_class;
412 	dev_set_name(&shost->shost_dev, "host%d", shost->host_no);
413 	shost->shost_dev.groups = scsi_sysfs_shost_attr_groups;
414 
415 	shost->ehandler = kthread_run(scsi_error_handler, shost,
416 			"scsi_eh_%d", shost->host_no);
417 	if (IS_ERR(shost->ehandler)) {
418 		rval = PTR_ERR(shost->ehandler);
419 		goto fail_kfree;
420 	}
421 
422 	scsi_proc_hostdir_add(shost->hostt);
423 	return shost;
424 
425  fail_kfree:
426 	kfree(shost);
427 	return NULL;
428 }
429 EXPORT_SYMBOL(scsi_host_alloc);
430 
431 struct Scsi_Host *scsi_register(struct scsi_host_template *sht, int privsize)
432 {
433 	struct Scsi_Host *shost = scsi_host_alloc(sht, privsize);
434 
435 	if (!sht->detect) {
436 		printk(KERN_WARNING "scsi_register() called on new-style "
437 				    "template for driver %s\n", sht->name);
438 		dump_stack();
439 	}
440 
441 	if (shost)
442 		list_add_tail(&shost->sht_legacy_list, &sht->legacy_hosts);
443 	return shost;
444 }
445 EXPORT_SYMBOL(scsi_register);
446 
447 void scsi_unregister(struct Scsi_Host *shost)
448 {
449 	list_del(&shost->sht_legacy_list);
450 	scsi_host_put(shost);
451 }
452 EXPORT_SYMBOL(scsi_unregister);
453 
454 static int __scsi_host_match(struct device *dev, void *data)
455 {
456 	struct Scsi_Host *p;
457 	unsigned short *hostnum = (unsigned short *)data;
458 
459 	p = class_to_shost(dev);
460 	return p->host_no == *hostnum;
461 }
462 
463 /**
464  * scsi_host_lookup - get a reference to a Scsi_Host by host no
465  * @hostnum:	host number to locate
466  *
467  * Return value:
468  *	A pointer to located Scsi_Host or NULL.
469  *
470  *	The caller must do a scsi_host_put() to drop the reference
471  *	that scsi_host_get() took. The put_device() below dropped
472  *	the reference from class_find_device().
473  **/
474 struct Scsi_Host *scsi_host_lookup(unsigned short hostnum)
475 {
476 	struct device *cdev;
477 	struct Scsi_Host *shost = NULL;
478 
479 	cdev = class_find_device(&shost_class, NULL, &hostnum,
480 				 __scsi_host_match);
481 	if (cdev) {
482 		shost = scsi_host_get(class_to_shost(cdev));
483 		put_device(cdev);
484 	}
485 	return shost;
486 }
487 EXPORT_SYMBOL(scsi_host_lookup);
488 
489 /**
490  * scsi_host_get - inc a Scsi_Host ref count
491  * @shost:	Pointer to Scsi_Host to inc.
492  **/
493 struct Scsi_Host *scsi_host_get(struct Scsi_Host *shost)
494 {
495 	if ((shost->shost_state == SHOST_DEL) ||
496 		!get_device(&shost->shost_gendev))
497 		return NULL;
498 	return shost;
499 }
500 EXPORT_SYMBOL(scsi_host_get);
501 
502 /**
503  * scsi_host_put - dec a Scsi_Host ref count
504  * @shost:	Pointer to Scsi_Host to dec.
505  **/
506 void scsi_host_put(struct Scsi_Host *shost)
507 {
508 	put_device(&shost->shost_gendev);
509 }
510 EXPORT_SYMBOL(scsi_host_put);
511 
512 int scsi_init_hosts(void)
513 {
514 	return class_register(&shost_class);
515 }
516 
517 void scsi_exit_hosts(void)
518 {
519 	class_unregister(&shost_class);
520 }
521 
522 int scsi_is_host_device(const struct device *dev)
523 {
524 	return dev->type == &scsi_host_type;
525 }
526 EXPORT_SYMBOL(scsi_is_host_device);
527 
528 /**
529  * scsi_queue_work - Queue work to the Scsi_Host workqueue.
530  * @shost:	Pointer to Scsi_Host.
531  * @work:	Work to queue for execution.
532  *
533  * Return value:
534  * 	1 - work queued for execution
535  *	0 - work is already queued
536  *	-EINVAL - work queue doesn't exist
537  **/
538 int scsi_queue_work(struct Scsi_Host *shost, struct work_struct *work)
539 {
540 	if (unlikely(!shost->work_q)) {
541 		printk(KERN_ERR
542 			"ERROR: Scsi host '%s' attempted to queue scsi-work, "
543 			"when no workqueue created.\n", shost->hostt->name);
544 		dump_stack();
545 
546 		return -EINVAL;
547 	}
548 
549 	return queue_work(shost->work_q, work);
550 }
551 EXPORT_SYMBOL_GPL(scsi_queue_work);
552 
553 /**
554  * scsi_flush_work - Flush a Scsi_Host's workqueue.
555  * @shost:	Pointer to Scsi_Host.
556  **/
557 void scsi_flush_work(struct Scsi_Host *shost)
558 {
559 	if (!shost->work_q) {
560 		printk(KERN_ERR
561 			"ERROR: Scsi host '%s' attempted to flush scsi-work, "
562 			"when no workqueue created.\n", shost->hostt->name);
563 		dump_stack();
564 		return;
565 	}
566 
567 	flush_workqueue(shost->work_q);
568 }
569 EXPORT_SYMBOL_GPL(scsi_flush_work);
570