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
43static int scsi_host_next_hn;		/* host_no for next new host */
44
45
46static void scsi_host_cls_release(struct class_device *class_dev)
47{
48	put_device(&class_to_shost(class_dev)->shost_gendev);
49}
50
51static 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 **/
65int 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}
150EXPORT_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 **/
156void 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}
182EXPORT_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 **/
192int 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}
255EXPORT_SYMBOL(scsi_add_host);
256
257static 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	if (shost->uspace_req_q) {
267		kfree(shost->uspace_req_q->queuedata);
268		scsi_free_queue(shost->uspace_req_q);
269	}
270
271	scsi_destroy_command_freelist(shost);
272	if (shost->bqt)
273		blk_free_tags(shost->bqt);
274
275	kfree(shost->shost_data);
276
277	if (parent)
278		put_device(parent);
279	kfree(shost);
280}
281
282/**
283 * scsi_host_alloc - register a scsi host adapter instance.
284 * @sht:	pointer to scsi host template
285 * @privsize:	extra bytes to allocate for driver
286 *
287 * Note:
288 * 	Allocate a new Scsi_Host and perform basic initialization.
289 * 	The host is not published to the scsi midlayer until scsi_add_host
290 * 	is called.
291 *
292 * Return value:
293 * 	Pointer to a new Scsi_Host
294 **/
295struct Scsi_Host *scsi_host_alloc(struct scsi_host_template *sht, int privsize)
296{
297	struct Scsi_Host *shost;
298	gfp_t gfp_mask = GFP_KERNEL;
299	int rval;
300
301	if (sht->unchecked_isa_dma && privsize)
302		gfp_mask |= __GFP_DMA;
303
304	shost = kzalloc(sizeof(struct Scsi_Host) + privsize, gfp_mask);
305	if (!shost)
306		return NULL;
307
308	shost->host_lock = &shost->default_lock;
309	spin_lock_init(shost->host_lock);
310	shost->shost_state = SHOST_CREATED;
311	INIT_LIST_HEAD(&shost->__devices);
312	INIT_LIST_HEAD(&shost->__targets);
313	INIT_LIST_HEAD(&shost->eh_cmd_q);
314	INIT_LIST_HEAD(&shost->starved_list);
315	init_waitqueue_head(&shost->host_wait);
316
317	mutex_init(&shost->scan_mutex);
318
319	shost->host_no = scsi_host_next_hn++;
320	shost->dma_channel = 0xff;
321
322	/* These three are default values which can be overridden */
323	shost->max_channel = 0;
324	shost->max_id = 8;
325	shost->max_lun = 8;
326
327	/* Give each shost a default transportt */
328	shost->transportt = &blank_transport_template;
329
330	/*
331	 * All drivers right now should be able to handle 12 byte
332	 * commands.  Every so often there are requests for 16 byte
333	 * commands, but individual low-level drivers need to certify that
334	 * they actually do something sensible with such commands.
335	 */
336	shost->max_cmd_len = 12;
337	shost->hostt = sht;
338	shost->this_id = sht->this_id;
339	shost->can_queue = sht->can_queue;
340	shost->sg_tablesize = sht->sg_tablesize;
341	shost->cmd_per_lun = sht->cmd_per_lun;
342	shost->unchecked_isa_dma = sht->unchecked_isa_dma;
343	shost->use_clustering = sht->use_clustering;
344	shost->ordered_tag = sht->ordered_tag;
345
346	if (sht->max_host_blocked)
347		shost->max_host_blocked = sht->max_host_blocked;
348	else
349		shost->max_host_blocked = SCSI_DEFAULT_HOST_BLOCKED;
350
351	/*
352	 * If the driver imposes no hard sector transfer limit, start at
353	 * machine infinity initially.
354	 */
355	if (sht->max_sectors)
356		shost->max_sectors = sht->max_sectors;
357	else
358		shost->max_sectors = SCSI_DEFAULT_MAX_SECTORS;
359
360	/*
361	 * assume a 4GB boundary, if not set
362	 */
363	if (sht->dma_boundary)
364		shost->dma_boundary = sht->dma_boundary;
365	else
366		shost->dma_boundary = 0xffffffff;
367
368	rval = scsi_setup_command_freelist(shost);
369	if (rval)
370		goto fail_kfree;
371
372	device_initialize(&shost->shost_gendev);
373	snprintf(shost->shost_gendev.bus_id, BUS_ID_SIZE, "host%d",
374		shost->host_no);
375	shost->shost_gendev.release = scsi_host_dev_release;
376
377	class_device_initialize(&shost->shost_classdev);
378	shost->shost_classdev.dev = &shost->shost_gendev;
379	shost->shost_classdev.class = &shost_class;
380	snprintf(shost->shost_classdev.class_id, BUS_ID_SIZE, "host%d",
381		  shost->host_no);
382
383	shost->ehandler = kthread_run(scsi_error_handler, shost,
384			"scsi_eh_%d", shost->host_no);
385	if (IS_ERR(shost->ehandler)) {
386		rval = PTR_ERR(shost->ehandler);
387		goto fail_destroy_freelist;
388	}
389
390	scsi_proc_hostdir_add(shost->hostt);
391	return shost;
392
393 fail_destroy_freelist:
394	scsi_destroy_command_freelist(shost);
395 fail_kfree:
396	kfree(shost);
397	return NULL;
398}
399EXPORT_SYMBOL(scsi_host_alloc);
400
401struct Scsi_Host *scsi_register(struct scsi_host_template *sht, int privsize)
402{
403	struct Scsi_Host *shost = scsi_host_alloc(sht, privsize);
404
405	if (!sht->detect) {
406		printk(KERN_WARNING "scsi_register() called on new-style "
407				    "template for driver %s\n", sht->name);
408		dump_stack();
409	}
410
411	if (shost)
412		list_add_tail(&shost->sht_legacy_list, &sht->legacy_hosts);
413	return shost;
414}
415EXPORT_SYMBOL(scsi_register);
416
417void scsi_unregister(struct Scsi_Host *shost)
418{
419	list_del(&shost->sht_legacy_list);
420	scsi_host_put(shost);
421}
422EXPORT_SYMBOL(scsi_unregister);
423
424/**
425 * scsi_host_lookup - get a reference to a Scsi_Host by host no
426 *
427 * @hostnum:	host number to locate
428 *
429 * Return value:
430 *	A pointer to located Scsi_Host or NULL.
431 **/
432struct Scsi_Host *scsi_host_lookup(unsigned short hostnum)
433{
434	struct class *class = &shost_class;
435	struct class_device *cdev;
436	struct Scsi_Host *shost = ERR_PTR(-ENXIO), *p;
437
438	down(&class->sem);
439	list_for_each_entry(cdev, &class->children, node) {
440		p = class_to_shost(cdev);
441		if (p->host_no == hostnum) {
442			shost = scsi_host_get(p);
443			break;
444		}
445	}
446	up(&class->sem);
447
448	return shost;
449}
450EXPORT_SYMBOL(scsi_host_lookup);
451
452/**
453 * scsi_host_get - inc a Scsi_Host ref count
454 * @shost:	Pointer to Scsi_Host to inc.
455 **/
456struct Scsi_Host *scsi_host_get(struct Scsi_Host *shost)
457{
458	if ((shost->shost_state == SHOST_DEL) ||
459		!get_device(&shost->shost_gendev))
460		return NULL;
461	return shost;
462}
463EXPORT_SYMBOL(scsi_host_get);
464
465/**
466 * scsi_host_put - dec a Scsi_Host ref count
467 * @shost:	Pointer to Scsi_Host to dec.
468 **/
469void scsi_host_put(struct Scsi_Host *shost)
470{
471	put_device(&shost->shost_gendev);
472}
473EXPORT_SYMBOL(scsi_host_put);
474
475int scsi_init_hosts(void)
476{
477	return class_register(&shost_class);
478}
479
480void scsi_exit_hosts(void)
481{
482	class_unregister(&shost_class);
483}
484
485int scsi_is_host_device(const struct device *dev)
486{
487	return dev->release == scsi_host_dev_release;
488}
489EXPORT_SYMBOL(scsi_is_host_device);
490
491/**
492 * scsi_queue_work - Queue work to the Scsi_Host workqueue.
493 * @shost:	Pointer to Scsi_Host.
494 * @work:	Work to queue for execution.
495 *
496 * Return value:
497 * 	1 - work queued for execution
498 *	0 - work is already queued
499 *	-EINVAL - work queue doesn't exist
500 **/
501int scsi_queue_work(struct Scsi_Host *shost, struct work_struct *work)
502{
503	if (unlikely(!shost->work_q)) {
504		printk(KERN_ERR
505			"ERROR: Scsi host '%s' attempted to queue scsi-work, "
506			"when no workqueue created.\n", shost->hostt->name);
507		dump_stack();
508
509		return -EINVAL;
510	}
511
512	return queue_work(shost->work_q, work);
513}
514EXPORT_SYMBOL_GPL(scsi_queue_work);
515
516/**
517 * scsi_flush_work - Flush a Scsi_Host's workqueue.
518 * @shost:	Pointer to Scsi_Host.
519 **/
520void scsi_flush_work(struct Scsi_Host *shost)
521{
522	if (!shost->work_q) {
523		printk(KERN_ERR
524			"ERROR: Scsi host '%s' attempted to flush scsi-work, "
525			"when no workqueue created.\n", shost->hostt->name);
526		dump_stack();
527		return;
528	}
529
530	flush_workqueue(shost->work_q);
531}
532EXPORT_SYMBOL_GPL(scsi_flush_work);
533