aboutsummaryrefslogtreecommitdiffstats
path: root/sound/core/init.c
blob: c72a79115cca2e64ecc36fc9de1fae40bc24f2f3 (plain) (blame)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
698
699
700
701
702
703
704
705
706
707
708
709
710
711
712
713
714
715
716
717
718
719
720
721
722
723
724
725
726
727
728
729
730
731
732
733
734
735
736
737
738
739
740
741
742
743
744
745
746
747
748
749
750
751
752
753
754
755
756
757
758
759
760
761
762
763
764
765
766
767
768
769
770
771
772
773
774
775
776
777
778
779
780
781
782
783
784
785
786
787
788
789
790
791
792
793
794
795
796
797
798
799
800
801
802
803
804
805
806
807
808
809
810
811
812
813
814
815
816
817
818
819
820
821
822
823
824
825
826
827
828
829
830
831
832
833
834
835
836
837
838
839
840
841
842
843
844
845
846
847
848
849
850
851
852
853
854
855
856
857
858
859
860
861
862
863
864
865
866
867
868
869
870
871
872
873
874
875
876
877
878
879
880
881
882
883
884
885
886
887
888
889
890
891
892
893
894
895
896
897
898
899
900
901
902
903
904
905
906
/*
 *  Initialization routines
 *  Copyright (c) by Jaroslav Kysela <perex@suse.cz>
 *
 *
 *   This program is free software; you can redistribute it and/or modify
 *   it under the terms of the GNU General Public License as published by
 *   the Free Software Foundation; either version 2 of the License, or
 *   (at your option) any later version.
 *
 *   This program is distributed in the hope that it will be useful,
 *   but WITHOUT ANY WARRANTY; without even the implied warranty of
 *   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 *   GNU General Public License for more details.
 *
 *   You should have received a copy of the GNU General Public License
 *   along with this program; if not, write to the Free Software
 *   Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307 USA
 *
 */

#include <sound/driver.h>
#include <linux/init.h>
#include <linux/sched.h>
#include <linux/file.h>
#include <linux/slab.h>
#include <linux/time.h>
#include <linux/ctype.h>
#include <linux/pci.h>
#include <linux/pm.h>
#include <sound/core.h>
#include <sound/control.h>
#include <sound/info.h>

struct snd_shutdown_f_ops {
	struct file_operations f_ops;
	struct snd_shutdown_f_ops *next;
};

unsigned int snd_cards_lock = 0;	/* locked for registering/using */
snd_card_t *snd_cards[SNDRV_CARDS] = {[0 ... (SNDRV_CARDS-1)] = NULL};
DEFINE_RWLOCK(snd_card_rwlock);

#if defined(CONFIG_SND_MIXER_OSS) || defined(CONFIG_SND_MIXER_OSS_MODULE)
int (*snd_mixer_oss_notify_callback)(snd_card_t *card, int free_flag);
#endif

static void snd_card_id_read(snd_info_entry_t *entry, snd_info_buffer_t * buffer)
{
	snd_iprintf(buffer, "%s\n", entry->card->id);
}

static void snd_card_free_thread(void * __card);

/**
 *  snd_card_new - create and initialize a soundcard structure
 *  @idx: card index (address) [0 ... (SNDRV_CARDS-1)]
 *  @xid: card identification (ASCII string)
 *  @module: top level module for locking
 *  @extra_size: allocate this extra size after the main soundcard structure
 *
 *  Creates and initializes a soundcard structure.
 *
 *  Returns kmallocated snd_card_t structure. Creates the ALSA control interface
 *  (which is blocked until snd_card_register function is called).
 */
snd_card_t *snd_card_new(int idx, const char *xid,
			 struct module *module, int extra_size)
{
	snd_card_t *card;
	int err;

	if (extra_size < 0)
		extra_size = 0;
	card = kzalloc(sizeof(*card) + extra_size, GFP_KERNEL);
	if (card == NULL)
		return NULL;
	if (xid) {
		if (!snd_info_check_reserved_words(xid))
			goto __error;
		strlcpy(card->id, xid, sizeof(card->id));
	}
	err = 0;
	write_lock(&snd_card_rwlock);
	if (idx < 0) {
		int idx2;
		for (idx2 = 0; idx2 < SNDRV_CARDS; idx2++)
			if (~snd_cards_lock & idx & 1<<idx2) {
				idx = idx2;
				if (idx >= snd_ecards_limit)
					snd_ecards_limit = idx + 1;
				break;
			}
	} else if (idx < snd_ecards_limit) {
		if (snd_cards_lock & (1 << idx))
			err = -ENODEV;	/* invalid */
	} else if (idx < SNDRV_CARDS)
		snd_ecards_limit = idx + 1; /* increase the limit */
	else
		err = -ENODEV;
	if (idx < 0 || err < 0) {
		write_unlock(&snd_card_rwlock);
		snd_printk(KERN_ERR "cannot find the slot for index %d (range 0-%i)\n", idx, snd_ecards_limit - 1);
		goto __error;
	}
	snd_cards_lock |= 1 << idx;		/* lock it */
	write_unlock(&snd_card_rwlock);
	card->number = idx;
	card->module = module;
	INIT_LIST_HEAD(&card->devices);
	init_rwsem(&card->controls_rwsem);
	rwlock_init(&card->ctl_files_rwlock);
	INIT_LIST_HEAD(&card->controls);
	INIT_LIST_HEAD(&card->ctl_files);
	spin_lock_init(&card->files_lock);
	init_waitqueue_head(&card->shutdown_sleep);
	INIT_WORK(&card->free_workq, snd_card_free_thread, card);
#ifdef CONFIG_PM
	init_MUTEX(&card->power_lock);
	init_waitqueue_head(&card->power_sleep);
#endif
	/* the control interface cannot be accessed from the user space until */
	/* snd_cards_bitmask and snd_cards are set with snd_card_register */
	if ((err = snd_ctl_create(card)) < 0) {
		snd_printd("unable to register control minors\n");
		goto __error;
	}
	if ((err = snd_info_card_create(card)) < 0) {
		snd_printd("unable to create card info\n");
		goto __error_ctl;
	}
	if (extra_size > 0)
		card->private_data = (char *)card + sizeof(snd_card_t);
	return card;

      __error_ctl:
	snd_device_free_all(card, SNDRV_DEV_CMD_PRE);
      __error:
	kfree(card);
      	return NULL;
}

static unsigned int snd_disconnect_poll(struct file * file, poll_table * wait)
{
	return POLLERR | POLLNVAL;
}

/**
 *  snd_card_disconnect - disconnect all APIs from the file-operations (user space)
 *  @card: soundcard structure
 *
 *  Disconnects all APIs from the file-operations (user space).
 *
 *  Returns zero, otherwise a negative error code.
 *
 *  Note: The current implementation replaces all active file->f_op with special
 *        dummy file operations (they do nothing except release).
 */
int snd_card_disconnect(snd_card_t * card)
{
	struct snd_monitor_file *mfile;
	struct file *file;
	struct snd_shutdown_f_ops *s_f_ops;
	struct file_operations *f_ops, *old_f_ops;
	int err;

	spin_lock(&card->files_lock);
	if (card->shutdown) {
		spin_unlock(&card->files_lock);
		return 0;
	}
	card->shutdown = 1;
	spin_unlock(&card->files_lock);

	/* phase 1: disable fops (user space) operations for ALSA API */
	write_lock(&snd_card_rwlock);
	snd_cards[card->number] = NULL;
	write_unlock(&snd_card_rwlock);
	
	/* phase 2: replace file->f_op with special dummy operations */
	
	spin_lock(&card->files_lock);
	mfile = card->files;
	while (mfile) {
		file = mfile->file;

		/* it's critical part, use endless loop */
		/* we have no room to fail */
		s_f_ops = kmalloc(sizeof(struct snd_shutdown_f_ops), GFP_ATOMIC);
		if (s_f_ops == NULL)
			panic("Atomic allocation failed for snd_shutdown_f_ops!");

		f_ops = &s_f_ops->f_ops;

		memset(f_ops, 0, sizeof(*f_ops));
		f_ops->owner = file->f_op->owner;
		f_ops->release = file->f_op->release;
		f_ops->poll = snd_disconnect_poll;

		s_f_ops->next = card->s_f_ops;
		card->s_f_ops = s_f_ops;
		
		f_ops = fops_get(f_ops);

		old_f_ops = file->f_op;
		file->f_op = f_ops;	/* must be atomic */
		fops_put(old_f_ops);
		
		mfile = mfile->next;
	}
	spin_unlock(&card->files_lock);	

	/* phase 3: notify all connected devices about disconnection */
	/* at this point, they cannot respond to any calls except release() */

#if defined(CONFIG_SND_MIXER_OSS) || defined(CONFIG_SND_MIXER_OSS_MODULE)
	if (snd_mixer_oss_notify_callback)
		snd_mixer_oss_notify_callback(card, SND_MIXER_OSS_NOTIFY_DISCONNECT);
#endif

	/* notify all devices that we are disconnected */
	err = snd_device_disconnect_all(card);
	if (err < 0)
		snd_printk(KERN_ERR "not all devices for card %i can be disconnected\n", card->number);

	return 0;	
}

#ifdef CONFIG_SND_GENERIC_DRIVER
static void snd_generic_device_unregister(snd_card_t *card);
#else
#define snd_generic_device_unregister(x) /*NOP*/
#endif

/**
 *  snd_card_free - frees given soundcard structure
 *  @card: soundcard structure
 *
 *  This function releases the soundcard structure and the all assigned
 *  devices automatically.  That is, you don't have to release the devices
 *  by yourself.
 *
 *  Returns zero. Frees all associated devices and frees the control
 *  interface associated to given soundcard.
 */
int snd_card_free(snd_card_t * card)
{
	struct snd_shutdown_f_ops *s_f_ops;

	if (card == NULL)
		return -EINVAL;
	write_lock(&snd_card_rwlock);
	snd_cards[card->number] = NULL;
	write_unlock(&snd_card_rwlock);

#ifdef CONFIG_PM
	wake_up(&card->power_sleep);
#endif
	/* wait, until all devices are ready for the free operation */
	wait_event(card->shutdown_sleep, card->files == NULL);

#if defined(CONFIG_SND_MIXER_OSS) || defined(CONFIG_SND_MIXER_OSS_MODULE)
	if (snd_mixer_oss_notify_callback)
		snd_mixer_oss_notify_callback(card, SND_MIXER_OSS_NOTIFY_FREE);
#endif
	if (snd_device_free_all(card, SNDRV_DEV_CMD_PRE) < 0) {
		snd_printk(KERN_ERR "unable to free all devices (pre)\n");
		/* Fatal, but this situation should never occur */
	}
	if (snd_device_free_all(card, SNDRV_DEV_CMD_NORMAL) < 0) {
		snd_printk(KERN_ERR "unable to free all devices (normal)\n");
		/* Fatal, but this situation should never occur */
	}
	if (snd_device_free_all(card, SNDRV_DEV_CMD_POST) < 0) {
		snd_printk(KERN_ERR "unable to free all devices (post)\n");
		/* Fatal, but this situation should never occur */
	}
	if (card->private_free)
		card->private_free(card);
	if (card->proc_id)
		snd_info_unregister(card->proc_id);
	if (snd_info_card_free(card) < 0) {
		snd_printk(KERN_WARNING "unable to free card info\n");
		/* Not fatal error */
	}
	snd_generic_device_unregister(card);
	while (card->s_f_ops) {
		s_f_ops = card->s_f_ops;
		card->s_f_ops = s_f_ops->next;
		kfree(s_f_ops);
	}
	write_lock(&snd_card_rwlock);
	snd_cards_lock &= ~(1 << card->number);
	write_unlock(&snd_card_rwlock);
	kfree(card);
	return 0;
}

static void snd_card_free_thread(void * __card)
{
	snd_card_t *card = __card;
	struct module * module = card->module;

	if (!try_module_get(module)) {
		snd_printk(KERN_ERR "unable to lock toplevel module for card %i in free thread\n", card->number);
		module = NULL;
	}

	snd_card_free(card);

	module_put(module);
}

/**
 *  snd_card_free_in_thread - call snd_card_free() in thread
 *  @card: soundcard structure
 *
 *  This function schedules the call of snd_card_free() function in a
 *  work queue.  When all devices are released (non-busy), the work
 *  is woken up and calls snd_card_free().
 *
 *  When a card can be disconnected at any time by hotplug service,
 *  this function should be used in disconnect (or detach) callback
 *  instead of calling snd_card_free() directly.
 *  
 *  Returns - zero otherwise a negative error code if the start of thread failed.
 */
int snd_card_free_in_thread(snd_card_t * card)
{
	if (card->files == NULL) {
		snd_card_free(card);
		return 0;
	}

	if (schedule_work(&card->free_workq))
		return 0;

	snd_printk(KERN_ERR "schedule_work() failed in snd_card_free_in_thread for card %i\n", card->number);
	/* try to free the structure immediately */
	snd_card_free(card);
	return -EFAULT;
}

static void choose_default_id(snd_card_t * card)
{
	int i, len, idx_flag = 0, loops = 8;
	char *id, *spos;
	
	id = spos = card->shortname;	
	while (*id != '\0') {
		if (*id == ' ')
			spos = id + 1;
		id++;
	}
	id = card->id;
	while (*spos != '\0' && !isalnum(*spos))
		spos++;
	if (isdigit(*spos))
		*id++ = isalpha(card->shortname[0]) ? card->shortname[0] : 'D';
	while (*spos != '\0' && (size_t)(id - card->id) < sizeof(card->id) - 1) {
		if (isalnum(*spos))
			*id++ = *spos;
		spos++;
	}
	*id = '\0';

	id = card->id;
	
	if (*id == '\0')
		strcpy(id, "default");

	while (1) {
	      	if (loops-- == 0) {
      			snd_printk(KERN_ERR "unable to choose default card id (%s)\n", id);
      			strcpy(card->id, card->proc_root->name);
      			return;
      		}
	      	if (!snd_info_check_reserved_words(id))
      			goto __change;
		for (i = 0; i < snd_ecards_limit; i++) {
			if (snd_cards[i] && !strcmp(snd_cards[i]->id, id))
				goto __change;
		}
		break;

	      __change:
		len = strlen(id);
		if (idx_flag)
			id[len-1]++;
		else if ((size_t)len <= sizeof(card->id) - 3) {
			strcat(id, "_1");
			idx_flag++;
		} else {
			spos = id + len - 2;
			if ((size_t)len <= sizeof(card->id) - 2)
				spos++;
			*spos++ = '_';
			*spos++ = '1';
			*spos++ = '\0';
			idx_flag++;
		}
	}
}

/**
 *  snd_card_register - register the soundcard
 *  @card: soundcard structure
 *
 *  This function registers all the devices assigned to the soundcard.
 *  Until calling this, the ALSA control interface is blocked from the
 *  external accesses.  Thus, you should call this function at the end
 *  of the initialization of the card.
 *
 *  Returns zero otherwise a negative error code if the registrain failed.
 */
int snd_card_register(snd_card_t * card)
{
	int err;
	snd_info_entry_t *entry;

	snd_runtime_check(card != NULL, return -EINVAL);
	if ((err = snd_device_register_all(card)) < 0)
		return err;
	write_lock(&snd_card_rwlock);
	if (snd_cards[card->number]) {
		/* already registered */
		write_unlock(&snd_card_rwlock);
		return 0;
	}
	if (card->id[0] == '\0')
		choose_default_id(card);
	snd_cards[card->number] = card;
	write_unlock(&snd_card_rwlock);
	if ((err = snd_info_card_register(card)) < 0) {
		snd_printd("unable to create card info\n");
		goto __skip_info;
	}
	if ((entry = snd_info_create_card_entry(card, "id", card->proc_root)) == NULL) {
		snd_printd("unable to create card entry\n");
		goto __skip_info;
	}
	entry->c.text.read_size = PAGE_SIZE;
	entry->c.text.read = snd_card_id_read;
	if (snd_info_register(entry) < 0) {
		snd_info_free_entry(entry);
		entry = NULL;
	}
	card->proc_id = entry;
      __skip_info:
#if defined(CONFIG_SND_MIXER_OSS) || defined(CONFIG_SND_MIXER_OSS_MODULE)
	if (snd_mixer_oss_notify_callback)
		snd_mixer_oss_notify_callback(card, SND_MIXER_OSS_NOTIFY_REGISTER);
#endif
	return 0;
}

static snd_info_entry_t *snd_card_info_entry = NULL;

static void snd_card_info_read(snd_info_entry_t *entry, snd_info_buffer_t * buffer)
{
	int idx, count;
	snd_card_t *card;

	for (idx = count = 0; idx < SNDRV_CARDS; idx++) {
		read_lock(&snd_card_rwlock);
		if ((card = snd_cards[idx]) != NULL) {
			count++;
			snd_iprintf(buffer, "%i [%-15s]: %s - %s\n",
					idx,
					card->id,
					card->driver,
					card->shortname);
			snd_iprintf(buffer, "                     %s\n",
					card->longname);
		}
		read_unlock(&snd_card_rwlock);
	}
	if (!count)
		snd_iprintf(buffer, "--- no soundcards ---\n");
}

#if defined(CONFIG_SND_OSSEMUL) && defined(CONFIG_PROC_FS)

void snd_card_info_read_oss(snd_info_buffer_t * buffer)
{
	int idx, count;
	snd_card_t *card;

	for (idx = count = 0; idx < SNDRV_CARDS; idx++) {
		read_lock(&snd_card_rwlock);
		if ((card = snd_cards[idx]) != NULL) {
			count++;
			snd_iprintf(buffer, "%s\n", card->longname);
		}
		read_unlock(&snd_card_rwlock);
	}
	if (!count) {
		snd_iprintf(buffer, "--- no soundcards ---\n");
	}
}

#endif

#ifdef MODULE
static snd_info_entry_t *snd_card_module_info_entry;
static void snd_card_module_info_read(snd_info_entry_t *entry, snd_info_buffer_t * buffer)
{
	int idx;
	snd_card_t *card;

	for (idx = 0; idx < SNDRV_CARDS; idx++) {
		read_lock(&snd_card_rwlock);
		if ((card = snd_cards[idx]) != NULL)
			snd_iprintf(buffer, "%i %s\n", idx, card->module->name);
		read_unlock(&snd_card_rwlock);
	}
}
#endif

int __init snd_card_info_init(void)
{
	snd_info_entry_t *entry;

	entry = snd_info_create_module_entry(THIS_MODULE, "cards", NULL);
	snd_runtime_check(entry != NULL, return -ENOMEM);
	entry->c.text.read_size = PAGE_SIZE;
	entry->c.text.read = snd_card_info_read;
	if (snd_info_register(entry) < 0) {
		snd_info_free_entry(entry);
		return -ENOMEM;
	}
	snd_card_info_entry = entry;

#ifdef MODULE
	entry = snd_info_create_module_entry(THIS_MODULE, "modules", NULL);
	if (entry) {
		entry->c.text.read_size = PAGE_SIZE;
		entry->c.text.read = snd_card_module_info_read;
		if (snd_info_register(entry) < 0)
			snd_info_free_entry(entry);
		else
			snd_card_module_info_entry = entry;
	}
#endif

	return 0;
}

int __exit snd_card_info_done(void)
{
	if (snd_card_info_entry)
		snd_info_unregister(snd_card_info_entry);
#ifdef MODULE
	if (snd_card_module_info_entry)
		snd_info_unregister(snd_card_module_info_entry);
#endif
	return 0;
}

/**
 *  snd_component_add - add a component string
 *  @card: soundcard structure
 *  @component: the component id string
 *
 *  This function adds the component id string to the supported list.
 *  The component can be referred from the alsa-lib.
 *
 *  Returns zero otherwise a negative error code.
 */
  
int snd_component_add(snd_card_t *card, const char *component)
{
	char *ptr;
	int len = strlen(component);

	ptr = strstr(card->components, component);
	if (ptr != NULL) {
		if (ptr[len] == '\0' || ptr[len] == ' ')	/* already there */
			return 1;
	}
	if (strlen(card->components) + 1 + len + 1 > sizeof(card->components)) {
		snd_BUG();
		return -ENOMEM;
	}
	if (card->components[0] != '\0')
		strcat(card->components, " ");
	strcat(card->components, component);
	return 0;
}

/**
 *  snd_card_file_add - add the file to the file list of the card
 *  @card: soundcard structure
 *  @file: file pointer
 *
 *  This function adds the file to the file linked-list of the card.
 *  This linked-list is used to keep tracking the connection state,
 *  and to avoid the release of busy resources by hotplug.
 *
 *  Returns zero or a negative error code.
 */
int snd_card_file_add(snd_card_t *card, struct file *file)
{
	struct snd_monitor_file *mfile;

	mfile = kmalloc(sizeof(*mfile), GFP_KERNEL);
	if (mfile == NULL)
		return -ENOMEM;
	mfile->file = file;
	mfile->next = NULL;
	spin_lock(&card->files_lock);
	if (card->shutdown) {
		spin_unlock(&card->files_lock);
		kfree(mfile);
		return -ENODEV;
	}
	mfile->next = card->files;
	card->files = mfile;
	spin_unlock(&card->files_lock);
	return 0;
}

/**
 *  snd_card_file_remove - remove the file from the file list
 *  @card: soundcard structure
 *  @file: file pointer
 *
 *  This function removes the file formerly added to the card via
 *  snd_card_file_add() function.
 *  If all files are removed and the release of the card is
 *  scheduled, it will wake up the the thread to call snd_card_free()
 *  (see snd_card_free_in_thread() function).
 *
 *  Returns zero or a negative error code.
 */
int snd_card_file_remove(snd_card_t *card, struct file *file)
{
	struct snd_monitor_file *mfile, *pfile = NULL;

	spin_lock(&card->files_lock);
	mfile = card->files;
	while (mfile) {
		if (mfile->file == file) {
			if (pfile)
				pfile->next = mfile->next;
			else
				card->files = mfile->next;
			break;
		}
		pfile = mfile;
		mfile = mfile->next;
	}
	spin_unlock(&card->files_lock);
	if (card->files == NULL)
		wake_up(&card->shutdown_sleep);
	if (!mfile) {
		snd_printk(KERN_ERR "ALSA card file remove problem (%p)\n", file);
		return -ENOENT;
	}
	kfree(mfile);
	return 0;
}

#ifdef CONFIG_SND_GENERIC_DRIVER
/*
 * generic device without a proper bus using platform_device
 * (e.g. ISA)
 */
struct snd_generic_device {
	struct platform_device pdev;
	snd_card_t *card;
};

#define get_snd_generic_card(dev)	container_of(to_platform_device(dev), struct snd_generic_device, pdev)->card

#define SND_GENERIC_NAME	"snd_generic"

#ifdef CONFIG_PM
static int snd_generic_suspend(struct device *dev, pm_message_t state, u32 level);
static int snd_generic_resume(struct device *dev, u32 level);
#endif

/* initialized in sound.c */
struct device_driver snd_generic_driver = {
	.name		= SND_GENERIC_NAME,
	.bus		= &platform_bus_type,
#ifdef CONFIG_PM
	.suspend	= snd_generic_suspend,
	.resume		= snd_generic_resume,
#endif
};

void snd_generic_device_release(struct device *dev)
{
}

static int snd_generic_device_register(snd_card_t *card)
{
	struct snd_generic_device *dev;
	int err;

	if (card->generic_dev)
		return 0; /* already registered */

	dev = kzalloc(sizeof(*dev), GFP_KERNEL);
	if (! dev) {
		snd_printk(KERN_ERR "can't allocate generic_device\n");
		return -ENOMEM;
	}

	dev->pdev.name = SND_GENERIC_NAME;
	dev->pdev.id = card->number;
	dev->pdev.dev.release = snd_generic_device_release;
	dev->card = card;
	if ((err = platform_device_register(&dev->pdev)) < 0) {
		kfree(dev);
		return err;
	}
	card->generic_dev = dev;
	return 0;
}

static void snd_generic_device_unregister(snd_card_t *card)
{
	struct snd_generic_device *dev = card->generic_dev;
	if (dev) {
		platform_device_unregister(&dev->pdev);
		kfree(dev);
		card->generic_dev = NULL;
	}
}

/**
 * snd_card_set_generic_dev - assign the generic device to the card
 * @card: soundcard structure
 *
 * Assigns a generic device to the card.  This function is provided as the
 * last resort, for devices without any proper bus.  Thus this won't override
 * the device already assigned to the card.
 * 
 * Returns zero if successful, or a negative error code.
 */
int snd_card_set_generic_dev(snd_card_t *card)
{
	int err;
	if ((err = snd_generic_device_register(card)) < 0)
		return err;
	if (! card->dev)
		snd_card_set_dev(card, &card->generic_dev->pdev.dev);
	return 0;
}
#endif /* CONFIG_SND_GENERIC_DRIVER */

#ifdef CONFIG_PM
/**
 *  snd_power_wait - wait until the power-state is changed.
 *  @card: soundcard structure
 *  @power_state: expected power state
 *  @file: file structure for the O_NONBLOCK check (optional)
 *
 *  Waits until the power-state is changed.
 *
 *  Note: the power lock must be active before call.
 */
int snd_power_wait(snd_card_t *card, unsigned int power_state, struct file *file)
{
	wait_queue_t wait;
	int result = 0;

	/* fastpath */
	if (snd_power_get_state(card) == power_state)
		return 0;
	init_waitqueue_entry(&wait, current);
	add_wait_queue(&card->power_sleep, &wait);
	while (1) {
		if (card->shutdown) {
			result = -ENODEV;
			break;
		}
		if (snd_power_get_state(card) == power_state)
			break;
#if 0 /* block all devices */
		if (file && (file->f_flags & O_NONBLOCK)) {
			result = -EAGAIN;
			break;
		}
#endif
		set_current_state(TASK_UNINTERRUPTIBLE);
		snd_power_unlock(card);
		schedule_timeout(30 * HZ);
		snd_power_lock(card);
	}
	remove_wait_queue(&card->power_sleep, &wait);
	return result;
}

/**
 * snd_card_set_pm_callback - set the PCI power-management callbacks
 * @card: soundcard structure
 * @suspend: suspend callback function
 * @resume: resume callback function
 * @private_data: private data to pass to the callback functions
 *
 * Sets the power-management callback functions of the card.
 * These callbacks are called from ALSA's common PCI suspend/resume
 * handler and from the control API.
 */
int snd_card_set_pm_callback(snd_card_t *card,
			     int (*suspend)(snd_card_t *, pm_message_t),
			     int (*resume)(snd_card_t *),
			     void *private_data)
{
	card->pm_suspend = suspend;
	card->pm_resume = resume;
	card->pm_private_data = private_data;
	return 0;
}

#ifdef CONFIG_SND_GENERIC_DRIVER
/* suspend/resume callbacks for snd_generic platform device */
static int snd_generic_suspend(struct device *dev, pm_message_t state, u32 level)
{
	snd_card_t *card;

	if (level != SUSPEND_DISABLE)
		return 0;

	card = get_snd_generic_card(dev);
	if (card->power_state == SNDRV_CTL_POWER_D3hot)
		return 0;
	if (card->pm_suspend)
		card->pm_suspend(card, PMSG_SUSPEND);
	snd_power_change_state(card, SNDRV_CTL_POWER_D3hot);
	return 0;
}

static int snd_generic_resume(struct device *dev, u32 level)
{
	snd_card_t *card;

	if (level != RESUME_ENABLE)
		return 0;

	card = get_snd_generic_card(dev);
	if (card->power_state == SNDRV_CTL_POWER_D0)
		return 0;
	if (card->pm_suspend)
		card->pm_resume(card);
	snd_power_change_state(card, SNDRV_CTL_POWER_D0);
	return 0;
}

/**
 * snd_card_set_generic_pm_callback - set the generic power-management callbacks
 * @card: soundcard structure
 * @suspend: suspend callback function
 * @resume: resume callback function
 * @private_data: private data to pass to the callback functions
 *
 * Registers the power-management and sets the lowlevel callbacks for
 * the given card.  These callbacks are called from the ALSA's common
 * PM handler and from the control API.
 */
int snd_card_set_generic_pm_callback(snd_card_t *card,
				 int (*suspend)(snd_card_t *, pm_message_t),
				 int (*resume)(snd_card_t *),
				 void *private_data)
{
	int err;
	if ((err = snd_generic_device_register(card)) < 0)
		return err;
	return snd_card_set_pm_callback(card, suspend, resume, private_data);
}
#endif /* CONFIG_SND_GENERIC_DRIVER */

#ifdef CONFIG_PCI
int snd_card_pci_suspend(struct pci_dev *dev, pm_message_t state)
{
	snd_card_t *card = pci_get_drvdata(dev);
	int err;
	if (! card || ! card->pm_suspend)
		return 0;
	if (card->power_state == SNDRV_CTL_POWER_D3hot)
		return 0;
	err = card->pm_suspend(card, PMSG_SUSPEND);
	pci_save_state(dev);
	snd_power_change_state(card, SNDRV_CTL_POWER_D3hot);
	return err;
}

int snd_card_pci_resume(struct pci_dev *dev)
{
	snd_card_t *card = pci_get_drvdata(dev);
	if (! card || ! card->pm_resume)
		return 0;
	if (card->power_state == SNDRV_CTL_POWER_D0)
		return 0;
	/* restore the PCI config space */
	pci_restore_state(dev);
	card->pm_resume(card);
	snd_power_change_state(card, SNDRV_CTL_POWER_D0);
	return 0;
}
#endif

#endif /* CONFIG_PM */