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
45static atomic_t scsi_host_next_hn;	/* host_no for next new host */
46
47
48static void scsi_host_cls_release(struct device *dev)
49{
50	put_device(&class_to_shost(dev)->shost_gendev);
51}
52
53static 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 **/
66int 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}
151EXPORT_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 **/
157void 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}
185EXPORT_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 **/
200int 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	if (!dma_dev)
222		dma_dev = shost->shost_gendev.parent;
223
224	shost->dma_dev = dma_dev;
225
226	error = device_add(&shost->shost_gendev);
227	if (error)
228		goto out;
229
230	pm_runtime_set_active(&shost->shost_gendev);
231	pm_runtime_enable(&shost->shost_gendev);
232	device_enable_async_suspend(&shost->shost_gendev);
233
234	scsi_host_set_state(shost, SHOST_RUNNING);
235	get_device(shost->shost_gendev.parent);
236
237	device_enable_async_suspend(&shost->shost_dev);
238
239	error = device_add(&shost->shost_dev);
240	if (error)
241		goto out_del_gendev;
242
243	get_device(&shost->shost_gendev);
244
245	if (shost->transportt->host_size) {
246		shost->shost_data = kzalloc(shost->transportt->host_size,
247					 GFP_KERNEL);
248		if (shost->shost_data == NULL) {
249			error = -ENOMEM;
250			goto out_del_dev;
251		}
252	}
253
254	if (shost->transportt->create_work_queue) {
255		snprintf(shost->work_q_name, sizeof(shost->work_q_name),
256			 "scsi_wq_%d", shost->host_no);
257		shost->work_q = create_singlethread_workqueue(
258					shost->work_q_name);
259		if (!shost->work_q) {
260			error = -EINVAL;
261			goto out_free_shost_data;
262		}
263	}
264
265	error = scsi_sysfs_add_host(shost);
266	if (error)
267		goto out_destroy_host;
268
269	scsi_proc_host_add(shost);
270	return error;
271
272 out_destroy_host:
273	if (shost->work_q)
274		destroy_workqueue(shost->work_q);
275 out_free_shost_data:
276	kfree(shost->shost_data);
277 out_del_dev:
278	device_del(&shost->shost_dev);
279 out_del_gendev:
280	device_del(&shost->shost_gendev);
281 out:
282	scsi_destroy_command_freelist(shost);
283 fail:
284	return error;
285}
286EXPORT_SYMBOL(scsi_add_host_with_dma);
287
288static void scsi_host_dev_release(struct device *dev)
289{
290	struct Scsi_Host *shost = dev_to_shost(dev);
291	struct device *parent = dev->parent;
292	struct request_queue *q;
293
294	scsi_proc_hostdir_rm(shost->hostt);
295
296	if (shost->ehandler)
297		kthread_stop(shost->ehandler);
298	if (shost->work_q)
299		destroy_workqueue(shost->work_q);
300	q = shost->uspace_req_q;
301	if (q) {
302		kfree(q->queuedata);
303		q->queuedata = NULL;
304		scsi_free_queue(q);
305	}
306
307	scsi_destroy_command_freelist(shost);
308	if (shost->bqt)
309		blk_free_tags(shost->bqt);
310
311	kfree(shost->shost_data);
312
313	if (parent)
314		put_device(parent);
315	kfree(shost);
316}
317
318static struct device_type scsi_host_type = {
319	.name =		"scsi_host",
320	.release =	scsi_host_dev_release,
321};
322
323/**
324 * scsi_host_alloc - register a scsi host adapter instance.
325 * @sht:	pointer to scsi host template
326 * @privsize:	extra bytes to allocate for driver
327 *
328 * Note:
329 * 	Allocate a new Scsi_Host and perform basic initialization.
330 * 	The host is not published to the scsi midlayer until scsi_add_host
331 * 	is called.
332 *
333 * Return value:
334 * 	Pointer to a new Scsi_Host
335 **/
336struct Scsi_Host *scsi_host_alloc(struct scsi_host_template *sht, int privsize)
337{
338	struct Scsi_Host *shost;
339	gfp_t gfp_mask = GFP_KERNEL;
340
341	if (sht->unchecked_isa_dma && privsize)
342		gfp_mask |= __GFP_DMA;
343
344	shost = kzalloc(sizeof(struct Scsi_Host) + privsize, gfp_mask);
345	if (!shost)
346		return NULL;
347
348	shost->host_lock = &shost->default_lock;
349	spin_lock_init(shost->host_lock);
350	shost->shost_state = SHOST_CREATED;
351	INIT_LIST_HEAD(&shost->__devices);
352	INIT_LIST_HEAD(&shost->__targets);
353	INIT_LIST_HEAD(&shost->eh_cmd_q);
354	INIT_LIST_HEAD(&shost->starved_list);
355	init_waitqueue_head(&shost->host_wait);
356
357	mutex_init(&shost->scan_mutex);
358
359	/*
360	 * subtract one because we increment first then return, but we need to
361	 * know what the next host number was before increment
362	 */
363	shost->host_no = atomic_inc_return(&scsi_host_next_hn) - 1;
364	shost->dma_channel = 0xff;
365
366	/* These three are default values which can be overridden */
367	shost->max_channel = 0;
368	shost->max_id = 8;
369	shost->max_lun = 8;
370
371	/* Give each shost a default transportt */
372	shost->transportt = &blank_transport_template;
373
374	/*
375	 * All drivers right now should be able to handle 12 byte
376	 * commands.  Every so often there are requests for 16 byte
377	 * commands, but individual low-level drivers need to certify that
378	 * they actually do something sensible with such commands.
379	 */
380	shost->max_cmd_len = 12;
381	shost->hostt = sht;
382	shost->this_id = sht->this_id;
383	shost->can_queue = sht->can_queue;
384	shost->sg_tablesize = sht->sg_tablesize;
385	shost->sg_prot_tablesize = sht->sg_prot_tablesize;
386	shost->cmd_per_lun = sht->cmd_per_lun;
387	shost->unchecked_isa_dma = sht->unchecked_isa_dma;
388	shost->use_clustering = sht->use_clustering;
389	shost->ordered_tag = sht->ordered_tag;
390
391	if (sht->supported_mode == MODE_UNKNOWN)
392		/* means we didn't set it ... default to INITIATOR */
393		shost->active_mode = MODE_INITIATOR;
394	else
395		shost->active_mode = sht->supported_mode;
396
397	if (sht->max_host_blocked)
398		shost->max_host_blocked = sht->max_host_blocked;
399	else
400		shost->max_host_blocked = SCSI_DEFAULT_HOST_BLOCKED;
401
402	/*
403	 * If the driver imposes no hard sector transfer limit, start at
404	 * machine infinity initially.
405	 */
406	if (sht->max_sectors)
407		shost->max_sectors = sht->max_sectors;
408	else
409		shost->max_sectors = SCSI_DEFAULT_MAX_SECTORS;
410
411	/*
412	 * assume a 4GB boundary, if not set
413	 */
414	if (sht->dma_boundary)
415		shost->dma_boundary = sht->dma_boundary;
416	else
417		shost->dma_boundary = 0xffffffff;
418
419	device_initialize(&shost->shost_gendev);
420	dev_set_name(&shost->shost_gendev, "host%d", shost->host_no);
421	shost->shost_gendev.bus = &scsi_bus_type;
422	shost->shost_gendev.type = &scsi_host_type;
423
424	device_initialize(&shost->shost_dev);
425	shost->shost_dev.parent = &shost->shost_gendev;
426	shost->shost_dev.class = &shost_class;
427	dev_set_name(&shost->shost_dev, "host%d", shost->host_no);
428	shost->shost_dev.groups = scsi_sysfs_shost_attr_groups;
429
430	shost->ehandler = kthread_run(scsi_error_handler, shost,
431			"scsi_eh_%d", shost->host_no);
432	if (IS_ERR(shost->ehandler)) {
433		printk(KERN_WARNING "scsi%d: error handler thread failed to spawn, error = %ld\n",
434			shost->host_no, PTR_ERR(shost->ehandler));
435		goto fail_kfree;
436	}
437
438	scsi_proc_hostdir_add(shost->hostt);
439	return shost;
440
441 fail_kfree:
442	kfree(shost);
443	return NULL;
444}
445EXPORT_SYMBOL(scsi_host_alloc);
446
447struct Scsi_Host *scsi_register(struct scsi_host_template *sht, int privsize)
448{
449	struct Scsi_Host *shost = scsi_host_alloc(sht, privsize);
450
451	if (!sht->detect) {
452		printk(KERN_WARNING "scsi_register() called on new-style "
453				    "template for driver %s\n", sht->name);
454		dump_stack();
455	}
456
457	if (shost)
458		list_add_tail(&shost->sht_legacy_list, &sht->legacy_hosts);
459	return shost;
460}
461EXPORT_SYMBOL(scsi_register);
462
463void scsi_unregister(struct Scsi_Host *shost)
464{
465	list_del(&shost->sht_legacy_list);
466	scsi_host_put(shost);
467}
468EXPORT_SYMBOL(scsi_unregister);
469
470static int __scsi_host_match(struct device *dev, void *data)
471{
472	struct Scsi_Host *p;
473	unsigned short *hostnum = (unsigned short *)data;
474
475	p = class_to_shost(dev);
476	return p->host_no == *hostnum;
477}
478
479/**
480 * scsi_host_lookup - get a reference to a Scsi_Host by host no
481 * @hostnum:	host number to locate
482 *
483 * Return value:
484 *	A pointer to located Scsi_Host or NULL.
485 *
486 *	The caller must do a scsi_host_put() to drop the reference
487 *	that scsi_host_get() took. The put_device() below dropped
488 *	the reference from class_find_device().
489 **/
490struct Scsi_Host *scsi_host_lookup(unsigned short hostnum)
491{
492	struct device *cdev;
493	struct Scsi_Host *shost = NULL;
494
495	cdev = class_find_device(&shost_class, NULL, &hostnum,
496				 __scsi_host_match);
497	if (cdev) {
498		shost = scsi_host_get(class_to_shost(cdev));
499		put_device(cdev);
500	}
501	return shost;
502}
503EXPORT_SYMBOL(scsi_host_lookup);
504
505/**
506 * scsi_host_get - inc a Scsi_Host ref count
507 * @shost:	Pointer to Scsi_Host to inc.
508 **/
509struct Scsi_Host *scsi_host_get(struct Scsi_Host *shost)
510{
511	if ((shost->shost_state == SHOST_DEL) ||
512		!get_device(&shost->shost_gendev))
513		return NULL;
514	return shost;
515}
516EXPORT_SYMBOL(scsi_host_get);
517
518/**
519 * scsi_host_put - dec a Scsi_Host ref count
520 * @shost:	Pointer to Scsi_Host to dec.
521 **/
522void scsi_host_put(struct Scsi_Host *shost)
523{
524	put_device(&shost->shost_gendev);
525}
526EXPORT_SYMBOL(scsi_host_put);
527
528int scsi_init_hosts(void)
529{
530	return class_register(&shost_class);
531}
532
533void scsi_exit_hosts(void)
534{
535	class_unregister(&shost_class);
536}
537
538int scsi_is_host_device(const struct device *dev)
539{
540	return dev->type == &scsi_host_type;
541}
542EXPORT_SYMBOL(scsi_is_host_device);
543
544/**
545 * scsi_queue_work - Queue work to the Scsi_Host workqueue.
546 * @shost:	Pointer to Scsi_Host.
547 * @work:	Work to queue for execution.
548 *
549 * Return value:
550 * 	1 - work queued for execution
551 *	0 - work is already queued
552 *	-EINVAL - work queue doesn't exist
553 **/
554int scsi_queue_work(struct Scsi_Host *shost, struct work_struct *work)
555{
556	if (unlikely(!shost->work_q)) {
557		printk(KERN_ERR
558			"ERROR: Scsi host '%s' attempted to queue scsi-work, "
559			"when no workqueue created.\n", shost->hostt->name);
560		dump_stack();
561
562		return -EINVAL;
563	}
564
565	return queue_work(shost->work_q, work);
566}
567EXPORT_SYMBOL_GPL(scsi_queue_work);
568
569/**
570 * scsi_flush_work - Flush a Scsi_Host's workqueue.
571 * @shost:	Pointer to Scsi_Host.
572 **/
573void scsi_flush_work(struct Scsi_Host *shost)
574{
575	if (!shost->work_q) {
576		printk(KERN_ERR
577			"ERROR: Scsi host '%s' attempted to flush scsi-work, "
578			"when no workqueue created.\n", shost->hostt->name);
579		dump_stack();
580		return;
581	}
582
583	flush_workqueue(shost->work_q);
584}
585EXPORT_SYMBOL_GPL(scsi_flush_work);
586