xref: /openbmc/linux/sound/core/init.c (revision 643d1f7f)
1 /*
2  *  Initialization routines
3  *  Copyright (c) by Jaroslav Kysela <perex@perex.cz>
4  *
5  *
6  *   This program is free software; you can redistribute it and/or modify
7  *   it under the terms of the GNU General Public License as published by
8  *   the Free Software Foundation; either version 2 of the License, or
9  *   (at your option) any later version.
10  *
11  *   This program is distributed in the hope that it will be useful,
12  *   but WITHOUT ANY WARRANTY; without even the implied warranty of
13  *   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
14  *   GNU General Public License for more details.
15  *
16  *   You should have received a copy of the GNU General Public License
17  *   along with this program; if not, write to the Free Software
18  *   Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307 USA
19  *
20  */
21 
22 #include <linux/init.h>
23 #include <linux/sched.h>
24 #include <linux/file.h>
25 #include <linux/slab.h>
26 #include <linux/time.h>
27 #include <linux/ctype.h>
28 #include <linux/pm.h>
29 
30 #include <sound/core.h>
31 #include <sound/control.h>
32 #include <sound/info.h>
33 
34 static DEFINE_SPINLOCK(shutdown_lock);
35 static LIST_HEAD(shutdown_files);
36 
37 static const struct file_operations snd_shutdown_f_ops;
38 
39 static unsigned int snd_cards_lock;	/* locked for registering/using */
40 struct snd_card *snd_cards[SNDRV_CARDS];
41 EXPORT_SYMBOL(snd_cards);
42 
43 static DEFINE_MUTEX(snd_card_mutex);
44 
45 static char *slots[SNDRV_CARDS];
46 module_param_array(slots, charp, NULL, 0444);
47 MODULE_PARM_DESC(slots, "Module names assigned to the slots.");
48 
49 /* return non-zero if the given index is already reserved for another
50  * module via slots option
51  */
52 static int module_slot_mismatch(struct module *module, int idx)
53 {
54 #ifdef MODULE
55 	char *s1, *s2;
56 	if (!module || !module->name || !slots[idx])
57 		return 0;
58 	s1 = slots[idx];
59 	s2 = module->name;
60 	/* compare module name strings
61 	 * hyphens are handled as equivalent with underscore
62 	 */
63 	for (;;) {
64 		char c1 = *s1++;
65 		char c2 = *s2++;
66 		if (c1 == '-')
67 			c1 = '_';
68 		if (c2 == '-')
69 			c2 = '_';
70 		if (c1 != c2)
71 			return 1;
72 		if (!c1)
73 			break;
74 	}
75 #endif
76 	return 0;
77 }
78 
79 #if defined(CONFIG_SND_MIXER_OSS) || defined(CONFIG_SND_MIXER_OSS_MODULE)
80 int (*snd_mixer_oss_notify_callback)(struct snd_card *card, int free_flag);
81 EXPORT_SYMBOL(snd_mixer_oss_notify_callback);
82 #endif
83 
84 #ifdef CONFIG_PROC_FS
85 static void snd_card_id_read(struct snd_info_entry *entry,
86 			     struct snd_info_buffer *buffer)
87 {
88 	snd_iprintf(buffer, "%s\n", entry->card->id);
89 }
90 
91 static inline int init_info_for_card(struct snd_card *card)
92 {
93 	int err;
94 	struct snd_info_entry *entry;
95 
96 	if ((err = snd_info_card_register(card)) < 0) {
97 		snd_printd("unable to create card info\n");
98 		return err;
99 	}
100 	if ((entry = snd_info_create_card_entry(card, "id", card->proc_root)) == NULL) {
101 		snd_printd("unable to create card entry\n");
102 		return err;
103 	}
104 	entry->c.text.read = snd_card_id_read;
105 	if (snd_info_register(entry) < 0) {
106 		snd_info_free_entry(entry);
107 		entry = NULL;
108 	}
109 	card->proc_id = entry;
110 	return 0;
111 }
112 #else /* !CONFIG_PROC_FS */
113 #define init_info_for_card(card)
114 #endif
115 
116 /**
117  *  snd_card_new - create and initialize a soundcard structure
118  *  @idx: card index (address) [0 ... (SNDRV_CARDS-1)]
119  *  @xid: card identification (ASCII string)
120  *  @module: top level module for locking
121  *  @extra_size: allocate this extra size after the main soundcard structure
122  *
123  *  Creates and initializes a soundcard structure.
124  *
125  *  Returns kmallocated snd_card structure. Creates the ALSA control interface
126  *  (which is blocked until snd_card_register function is called).
127  */
128 struct snd_card *snd_card_new(int idx, const char *xid,
129 			 struct module *module, int extra_size)
130 {
131 	struct snd_card *card;
132 	int err;
133 
134 	if (extra_size < 0)
135 		extra_size = 0;
136 	card = kzalloc(sizeof(*card) + extra_size, GFP_KERNEL);
137 	if (card == NULL)
138 		return NULL;
139 	if (xid) {
140 		if (!snd_info_check_reserved_words(xid))
141 			goto __error;
142 		strlcpy(card->id, xid, sizeof(card->id));
143 	}
144 	err = 0;
145 	mutex_lock(&snd_card_mutex);
146 	if (idx < 0) {
147 		int idx2;
148 		for (idx2 = 0; idx2 < SNDRV_CARDS; idx2++)
149 			/* idx == -1 == 0xffff means: take any free slot */
150 			if (~snd_cards_lock & idx & 1<<idx2) {
151 				if (module_slot_mismatch(module, idx2))
152 					continue;
153 				idx = idx2;
154 				if (idx >= snd_ecards_limit)
155 					snd_ecards_limit = idx + 1;
156 				break;
157 			}
158 	} else {
159 		 if (idx < snd_ecards_limit) {
160 			if (snd_cards_lock & (1 << idx))
161 				err = -EBUSY;	/* invalid */
162 		} else {
163 			if (idx < SNDRV_CARDS)
164 				snd_ecards_limit = idx + 1; /* increase the limit */
165 			else
166 				err = -ENODEV;
167 		}
168 	}
169 	if (idx < 0 || err < 0) {
170 		mutex_unlock(&snd_card_mutex);
171 		snd_printk(KERN_ERR "cannot find the slot for index %d (range 0-%i), error: %d\n",
172 			 idx, snd_ecards_limit - 1, err);
173 		goto __error;
174 	}
175 	snd_cards_lock |= 1 << idx;		/* lock it */
176 	mutex_unlock(&snd_card_mutex);
177 	card->number = idx;
178 	card->module = module;
179 	INIT_LIST_HEAD(&card->devices);
180 	init_rwsem(&card->controls_rwsem);
181 	rwlock_init(&card->ctl_files_rwlock);
182 	INIT_LIST_HEAD(&card->controls);
183 	INIT_LIST_HEAD(&card->ctl_files);
184 	spin_lock_init(&card->files_lock);
185 	init_waitqueue_head(&card->shutdown_sleep);
186 #ifdef CONFIG_PM
187 	mutex_init(&card->power_lock);
188 	init_waitqueue_head(&card->power_sleep);
189 #endif
190 	/* the control interface cannot be accessed from the user space until */
191 	/* snd_cards_bitmask and snd_cards are set with snd_card_register */
192 	if ((err = snd_ctl_create(card)) < 0) {
193 		snd_printd("unable to register control minors\n");
194 		goto __error;
195 	}
196 	if ((err = snd_info_card_create(card)) < 0) {
197 		snd_printd("unable to create card info\n");
198 		goto __error_ctl;
199 	}
200 	if (extra_size > 0)
201 		card->private_data = (char *)card + sizeof(struct snd_card);
202 	return card;
203 
204       __error_ctl:
205 	snd_device_free_all(card, SNDRV_DEV_CMD_PRE);
206       __error:
207 	kfree(card);
208       	return NULL;
209 }
210 
211 EXPORT_SYMBOL(snd_card_new);
212 
213 /* return non-zero if a card is already locked */
214 int snd_card_locked(int card)
215 {
216 	int locked;
217 
218 	mutex_lock(&snd_card_mutex);
219 	locked = snd_cards_lock & (1 << card);
220 	mutex_unlock(&snd_card_mutex);
221 	return locked;
222 }
223 
224 static loff_t snd_disconnect_llseek(struct file *file, loff_t offset, int orig)
225 {
226 	return -ENODEV;
227 }
228 
229 static ssize_t snd_disconnect_read(struct file *file, char __user *buf,
230 				   size_t count, loff_t *offset)
231 {
232 	return -ENODEV;
233 }
234 
235 static ssize_t snd_disconnect_write(struct file *file, const char __user *buf,
236 				    size_t count, loff_t *offset)
237 {
238 	return -ENODEV;
239 }
240 
241 static int snd_disconnect_release(struct inode *inode, struct file *file)
242 {
243 	struct snd_monitor_file *df = NULL, *_df;
244 
245 	spin_lock(&shutdown_lock);
246 	list_for_each_entry(_df, &shutdown_files, shutdown_list) {
247 		if (_df->file == file) {
248 			df = _df;
249 			break;
250 		}
251 	}
252 	spin_unlock(&shutdown_lock);
253 
254 	if (likely(df))
255 		return df->disconnected_f_op->release(inode, file);
256 
257 	panic("%s(%p, %p) failed!", __FUNCTION__, inode, file);
258 }
259 
260 static unsigned int snd_disconnect_poll(struct file * file, poll_table * wait)
261 {
262 	return POLLERR | POLLNVAL;
263 }
264 
265 static long snd_disconnect_ioctl(struct file *file,
266 				 unsigned int cmd, unsigned long arg)
267 {
268 	return -ENODEV;
269 }
270 
271 static int snd_disconnect_mmap(struct file *file, struct vm_area_struct *vma)
272 {
273 	return -ENODEV;
274 }
275 
276 static int snd_disconnect_fasync(int fd, struct file *file, int on)
277 {
278 	return -ENODEV;
279 }
280 
281 static const struct file_operations snd_shutdown_f_ops =
282 {
283 	.owner = 	THIS_MODULE,
284 	.llseek =	snd_disconnect_llseek,
285 	.read = 	snd_disconnect_read,
286 	.write =	snd_disconnect_write,
287 	.release =	snd_disconnect_release,
288 	.poll =		snd_disconnect_poll,
289 	.unlocked_ioctl = snd_disconnect_ioctl,
290 #ifdef CONFIG_COMPAT
291 	.compat_ioctl = snd_disconnect_ioctl,
292 #endif
293 	.mmap =		snd_disconnect_mmap,
294 	.fasync =	snd_disconnect_fasync
295 };
296 
297 /**
298  *  snd_card_disconnect - disconnect all APIs from the file-operations (user space)
299  *  @card: soundcard structure
300  *
301  *  Disconnects all APIs from the file-operations (user space).
302  *
303  *  Returns zero, otherwise a negative error code.
304  *
305  *  Note: The current implementation replaces all active file->f_op with special
306  *        dummy file operations (they do nothing except release).
307  */
308 int snd_card_disconnect(struct snd_card *card)
309 {
310 	struct snd_monitor_file *mfile;
311 	struct file *file;
312 	int err;
313 
314 	spin_lock(&card->files_lock);
315 	if (card->shutdown) {
316 		spin_unlock(&card->files_lock);
317 		return 0;
318 	}
319 	card->shutdown = 1;
320 	spin_unlock(&card->files_lock);
321 
322 	/* phase 1: disable fops (user space) operations for ALSA API */
323 	mutex_lock(&snd_card_mutex);
324 	snd_cards[card->number] = NULL;
325 	mutex_unlock(&snd_card_mutex);
326 
327 	/* phase 2: replace file->f_op with special dummy operations */
328 
329 	spin_lock(&card->files_lock);
330 	mfile = card->files;
331 	while (mfile) {
332 		file = mfile->file;
333 
334 		/* it's critical part, use endless loop */
335 		/* we have no room to fail */
336 		mfile->disconnected_f_op = mfile->file->f_op;
337 
338 		spin_lock(&shutdown_lock);
339 		list_add(&mfile->shutdown_list, &shutdown_files);
340 		spin_unlock(&shutdown_lock);
341 
342 		mfile->file->f_op = &snd_shutdown_f_ops;
343 		fops_get(mfile->file->f_op);
344 
345 		mfile = mfile->next;
346 	}
347 	spin_unlock(&card->files_lock);
348 
349 	/* phase 3: notify all connected devices about disconnection */
350 	/* at this point, they cannot respond to any calls except release() */
351 
352 #if defined(CONFIG_SND_MIXER_OSS) || defined(CONFIG_SND_MIXER_OSS_MODULE)
353 	if (snd_mixer_oss_notify_callback)
354 		snd_mixer_oss_notify_callback(card, SND_MIXER_OSS_NOTIFY_DISCONNECT);
355 #endif
356 
357 	/* notify all devices that we are disconnected */
358 	err = snd_device_disconnect_all(card);
359 	if (err < 0)
360 		snd_printk(KERN_ERR "not all devices for card %i can be disconnected\n", card->number);
361 
362 	snd_info_card_disconnect(card);
363 	return 0;
364 }
365 
366 EXPORT_SYMBOL(snd_card_disconnect);
367 
368 /**
369  *  snd_card_free - frees given soundcard structure
370  *  @card: soundcard structure
371  *
372  *  This function releases the soundcard structure and the all assigned
373  *  devices automatically.  That is, you don't have to release the devices
374  *  by yourself.
375  *
376  *  Returns zero. Frees all associated devices and frees the control
377  *  interface associated to given soundcard.
378  */
379 static int snd_card_do_free(struct snd_card *card)
380 {
381 #if defined(CONFIG_SND_MIXER_OSS) || defined(CONFIG_SND_MIXER_OSS_MODULE)
382 	if (snd_mixer_oss_notify_callback)
383 		snd_mixer_oss_notify_callback(card, SND_MIXER_OSS_NOTIFY_FREE);
384 #endif
385 	if (snd_device_free_all(card, SNDRV_DEV_CMD_PRE) < 0) {
386 		snd_printk(KERN_ERR "unable to free all devices (pre)\n");
387 		/* Fatal, but this situation should never occur */
388 	}
389 	if (snd_device_free_all(card, SNDRV_DEV_CMD_NORMAL) < 0) {
390 		snd_printk(KERN_ERR "unable to free all devices (normal)\n");
391 		/* Fatal, but this situation should never occur */
392 	}
393 	if (snd_device_free_all(card, SNDRV_DEV_CMD_POST) < 0) {
394 		snd_printk(KERN_ERR "unable to free all devices (post)\n");
395 		/* Fatal, but this situation should never occur */
396 	}
397 	if (card->private_free)
398 		card->private_free(card);
399 	snd_info_free_entry(card->proc_id);
400 	if (snd_info_card_free(card) < 0) {
401 		snd_printk(KERN_WARNING "unable to free card info\n");
402 		/* Not fatal error */
403 	}
404 #ifndef CONFIG_SYSFS_DEPRECATED
405 	if (card->card_dev)
406 		device_unregister(card->card_dev);
407 #endif
408 	kfree(card);
409 	return 0;
410 }
411 
412 static int snd_card_free_prepare(struct snd_card *card)
413 {
414 	if (card == NULL)
415 		return -EINVAL;
416 	(void) snd_card_disconnect(card);
417 	mutex_lock(&snd_card_mutex);
418 	snd_cards[card->number] = NULL;
419 	snd_cards_lock &= ~(1 << card->number);
420 	mutex_unlock(&snd_card_mutex);
421 #ifdef CONFIG_PM
422 	wake_up(&card->power_sleep);
423 #endif
424 	return 0;
425 }
426 
427 int snd_card_free_when_closed(struct snd_card *card)
428 {
429 	int free_now = 0;
430 	int ret = snd_card_free_prepare(card);
431 	if (ret)
432 		return ret;
433 
434 	spin_lock(&card->files_lock);
435 	if (card->files == NULL)
436 		free_now = 1;
437 	else
438 		card->free_on_last_close = 1;
439 	spin_unlock(&card->files_lock);
440 
441 	if (free_now)
442 		snd_card_do_free(card);
443 	return 0;
444 }
445 
446 EXPORT_SYMBOL(snd_card_free_when_closed);
447 
448 int snd_card_free(struct snd_card *card)
449 {
450 	int ret = snd_card_free_prepare(card);
451 	if (ret)
452 		return ret;
453 
454 	/* wait, until all devices are ready for the free operation */
455 	wait_event(card->shutdown_sleep, card->files == NULL);
456 	snd_card_do_free(card);
457 	return 0;
458 }
459 
460 EXPORT_SYMBOL(snd_card_free);
461 
462 static void choose_default_id(struct snd_card *card)
463 {
464 	int i, len, idx_flag = 0, loops = SNDRV_CARDS;
465 	char *id, *spos;
466 
467 	id = spos = card->shortname;
468 	while (*id != '\0') {
469 		if (*id == ' ')
470 			spos = id + 1;
471 		id++;
472 	}
473 	id = card->id;
474 	while (*spos != '\0' && !isalnum(*spos))
475 		spos++;
476 	if (isdigit(*spos))
477 		*id++ = isalpha(card->shortname[0]) ? card->shortname[0] : 'D';
478 	while (*spos != '\0' && (size_t)(id - card->id) < sizeof(card->id) - 1) {
479 		if (isalnum(*spos))
480 			*id++ = *spos;
481 		spos++;
482 	}
483 	*id = '\0';
484 
485 	id = card->id;
486 
487 	if (*id == '\0')
488 		strcpy(id, "default");
489 
490 	while (1) {
491 	      	if (loops-- == 0) {
492       			snd_printk(KERN_ERR "unable to choose default card id (%s)\n", id);
493       			strcpy(card->id, card->proc_root->name);
494       			return;
495       		}
496 	      	if (!snd_info_check_reserved_words(id))
497       			goto __change;
498 		for (i = 0; i < snd_ecards_limit; i++) {
499 			if (snd_cards[i] && !strcmp(snd_cards[i]->id, id))
500 				goto __change;
501 		}
502 		break;
503 
504 	      __change:
505 		len = strlen(id);
506 		if (idx_flag) {
507 			if (id[len-1] != '9')
508 				id[len-1]++;
509 			else
510 				id[len-1] = 'A';
511 		} else if ((size_t)len <= sizeof(card->id) - 3) {
512 			strcat(id, "_1");
513 			idx_flag++;
514 		} else {
515 			spos = id + len - 2;
516 			if ((size_t)len <= sizeof(card->id) - 2)
517 				spos++;
518 			*spos++ = '_';
519 			*spos++ = '1';
520 			*spos++ = '\0';
521 			idx_flag++;
522 		}
523 	}
524 }
525 
526 /**
527  *  snd_card_register - register the soundcard
528  *  @card: soundcard structure
529  *
530  *  This function registers all the devices assigned to the soundcard.
531  *  Until calling this, the ALSA control interface is blocked from the
532  *  external accesses.  Thus, you should call this function at the end
533  *  of the initialization of the card.
534  *
535  *  Returns zero otherwise a negative error code if the registrain failed.
536  */
537 int snd_card_register(struct snd_card *card)
538 {
539 	int err;
540 
541 	snd_assert(card != NULL, return -EINVAL);
542 #ifndef CONFIG_SYSFS_DEPRECATED
543 	if (!card->card_dev) {
544 		card->card_dev = device_create(sound_class, card->dev, 0,
545 					       "card%i", card->number);
546 		if (IS_ERR(card->card_dev))
547 			card->card_dev = NULL;
548 	}
549 #endif
550 	if ((err = snd_device_register_all(card)) < 0)
551 		return err;
552 	mutex_lock(&snd_card_mutex);
553 	if (snd_cards[card->number]) {
554 		/* already registered */
555 		mutex_unlock(&snd_card_mutex);
556 		return 0;
557 	}
558 	if (card->id[0] == '\0')
559 		choose_default_id(card);
560 	snd_cards[card->number] = card;
561 	mutex_unlock(&snd_card_mutex);
562 	init_info_for_card(card);
563 #if defined(CONFIG_SND_MIXER_OSS) || defined(CONFIG_SND_MIXER_OSS_MODULE)
564 	if (snd_mixer_oss_notify_callback)
565 		snd_mixer_oss_notify_callback(card, SND_MIXER_OSS_NOTIFY_REGISTER);
566 #endif
567 	return 0;
568 }
569 
570 EXPORT_SYMBOL(snd_card_register);
571 
572 #ifdef CONFIG_PROC_FS
573 static struct snd_info_entry *snd_card_info_entry;
574 
575 static void snd_card_info_read(struct snd_info_entry *entry,
576 			       struct snd_info_buffer *buffer)
577 {
578 	int idx, count;
579 	struct snd_card *card;
580 
581 	for (idx = count = 0; idx < SNDRV_CARDS; idx++) {
582 		mutex_lock(&snd_card_mutex);
583 		if ((card = snd_cards[idx]) != NULL) {
584 			count++;
585 			snd_iprintf(buffer, "%2i [%-15s]: %s - %s\n",
586 					idx,
587 					card->id,
588 					card->driver,
589 					card->shortname);
590 			snd_iprintf(buffer, "                      %s\n",
591 					card->longname);
592 		}
593 		mutex_unlock(&snd_card_mutex);
594 	}
595 	if (!count)
596 		snd_iprintf(buffer, "--- no soundcards ---\n");
597 }
598 
599 #ifdef CONFIG_SND_OSSEMUL
600 
601 void snd_card_info_read_oss(struct snd_info_buffer *buffer)
602 {
603 	int idx, count;
604 	struct snd_card *card;
605 
606 	for (idx = count = 0; idx < SNDRV_CARDS; idx++) {
607 		mutex_lock(&snd_card_mutex);
608 		if ((card = snd_cards[idx]) != NULL) {
609 			count++;
610 			snd_iprintf(buffer, "%s\n", card->longname);
611 		}
612 		mutex_unlock(&snd_card_mutex);
613 	}
614 	if (!count) {
615 		snd_iprintf(buffer, "--- no soundcards ---\n");
616 	}
617 }
618 
619 #endif
620 
621 #ifdef MODULE
622 static struct snd_info_entry *snd_card_module_info_entry;
623 static void snd_card_module_info_read(struct snd_info_entry *entry,
624 				      struct snd_info_buffer *buffer)
625 {
626 	int idx;
627 	struct snd_card *card;
628 
629 	for (idx = 0; idx < SNDRV_CARDS; idx++) {
630 		mutex_lock(&snd_card_mutex);
631 		if ((card = snd_cards[idx]) != NULL)
632 			snd_iprintf(buffer, "%2i %s\n",
633 				    idx, card->module->name);
634 		mutex_unlock(&snd_card_mutex);
635 	}
636 }
637 #endif
638 
639 int __init snd_card_info_init(void)
640 {
641 	struct snd_info_entry *entry;
642 
643 	entry = snd_info_create_module_entry(THIS_MODULE, "cards", NULL);
644 	if (! entry)
645 		return -ENOMEM;
646 	entry->c.text.read = snd_card_info_read;
647 	if (snd_info_register(entry) < 0) {
648 		snd_info_free_entry(entry);
649 		return -ENOMEM;
650 	}
651 	snd_card_info_entry = entry;
652 
653 #ifdef MODULE
654 	entry = snd_info_create_module_entry(THIS_MODULE, "modules", NULL);
655 	if (entry) {
656 		entry->c.text.read = snd_card_module_info_read;
657 		if (snd_info_register(entry) < 0)
658 			snd_info_free_entry(entry);
659 		else
660 			snd_card_module_info_entry = entry;
661 	}
662 #endif
663 
664 	return 0;
665 }
666 
667 int __exit snd_card_info_done(void)
668 {
669 	snd_info_free_entry(snd_card_info_entry);
670 #ifdef MODULE
671 	snd_info_free_entry(snd_card_module_info_entry);
672 #endif
673 	return 0;
674 }
675 
676 #endif /* CONFIG_PROC_FS */
677 
678 /**
679  *  snd_component_add - add a component string
680  *  @card: soundcard structure
681  *  @component: the component id string
682  *
683  *  This function adds the component id string to the supported list.
684  *  The component can be referred from the alsa-lib.
685  *
686  *  Returns zero otherwise a negative error code.
687  */
688 
689 int snd_component_add(struct snd_card *card, const char *component)
690 {
691 	char *ptr;
692 	int len = strlen(component);
693 
694 	ptr = strstr(card->components, component);
695 	if (ptr != NULL) {
696 		if (ptr[len] == '\0' || ptr[len] == ' ')	/* already there */
697 			return 1;
698 	}
699 	if (strlen(card->components) + 1 + len + 1 > sizeof(card->components)) {
700 		snd_BUG();
701 		return -ENOMEM;
702 	}
703 	if (card->components[0] != '\0')
704 		strcat(card->components, " ");
705 	strcat(card->components, component);
706 	return 0;
707 }
708 
709 EXPORT_SYMBOL(snd_component_add);
710 
711 /**
712  *  snd_card_file_add - add the file to the file list of the card
713  *  @card: soundcard structure
714  *  @file: file pointer
715  *
716  *  This function adds the file to the file linked-list of the card.
717  *  This linked-list is used to keep tracking the connection state,
718  *  and to avoid the release of busy resources by hotplug.
719  *
720  *  Returns zero or a negative error code.
721  */
722 int snd_card_file_add(struct snd_card *card, struct file *file)
723 {
724 	struct snd_monitor_file *mfile;
725 
726 	mfile = kmalloc(sizeof(*mfile), GFP_KERNEL);
727 	if (mfile == NULL)
728 		return -ENOMEM;
729 	mfile->file = file;
730 	mfile->disconnected_f_op = NULL;
731 	mfile->next = NULL;
732 	spin_lock(&card->files_lock);
733 	if (card->shutdown) {
734 		spin_unlock(&card->files_lock);
735 		kfree(mfile);
736 		return -ENODEV;
737 	}
738 	mfile->next = card->files;
739 	card->files = mfile;
740 	spin_unlock(&card->files_lock);
741 	return 0;
742 }
743 
744 EXPORT_SYMBOL(snd_card_file_add);
745 
746 /**
747  *  snd_card_file_remove - remove the file from the file list
748  *  @card: soundcard structure
749  *  @file: file pointer
750  *
751  *  This function removes the file formerly added to the card via
752  *  snd_card_file_add() function.
753  *  If all files are removed and snd_card_free_when_closed() was
754  *  called beforehand, it processes the pending release of
755  *  resources.
756  *
757  *  Returns zero or a negative error code.
758  */
759 int snd_card_file_remove(struct snd_card *card, struct file *file)
760 {
761 	struct snd_monitor_file *mfile, *pfile = NULL;
762 	int last_close = 0;
763 
764 	spin_lock(&card->files_lock);
765 	mfile = card->files;
766 	while (mfile) {
767 		if (mfile->file == file) {
768 			if (pfile)
769 				pfile->next = mfile->next;
770 			else
771 				card->files = mfile->next;
772 			break;
773 		}
774 		pfile = mfile;
775 		mfile = mfile->next;
776 	}
777 	if (mfile && mfile->disconnected_f_op) {
778 		fops_put(mfile->disconnected_f_op);
779 		spin_lock(&shutdown_lock);
780 		list_del(&mfile->shutdown_list);
781 		spin_unlock(&shutdown_lock);
782 	}
783 	if (card->files == NULL)
784 		last_close = 1;
785 	spin_unlock(&card->files_lock);
786 	if (last_close) {
787 		wake_up(&card->shutdown_sleep);
788 		if (card->free_on_last_close)
789 			snd_card_do_free(card);
790 	}
791 	if (!mfile) {
792 		snd_printk(KERN_ERR "ALSA card file remove problem (%p)\n", file);
793 		return -ENOENT;
794 	}
795 	kfree(mfile);
796 	return 0;
797 }
798 
799 EXPORT_SYMBOL(snd_card_file_remove);
800 
801 #ifdef CONFIG_PM
802 /**
803  *  snd_power_wait - wait until the power-state is changed.
804  *  @card: soundcard structure
805  *  @power_state: expected power state
806  *
807  *  Waits until the power-state is changed.
808  *
809  *  Note: the power lock must be active before call.
810  */
811 int snd_power_wait(struct snd_card *card, unsigned int power_state)
812 {
813 	wait_queue_t wait;
814 	int result = 0;
815 
816 	/* fastpath */
817 	if (snd_power_get_state(card) == power_state)
818 		return 0;
819 	init_waitqueue_entry(&wait, current);
820 	add_wait_queue(&card->power_sleep, &wait);
821 	while (1) {
822 		if (card->shutdown) {
823 			result = -ENODEV;
824 			break;
825 		}
826 		if (snd_power_get_state(card) == power_state)
827 			break;
828 		set_current_state(TASK_UNINTERRUPTIBLE);
829 		snd_power_unlock(card);
830 		schedule_timeout(30 * HZ);
831 		snd_power_lock(card);
832 	}
833 	remove_wait_queue(&card->power_sleep, &wait);
834 	return result;
835 }
836 
837 EXPORT_SYMBOL(snd_power_wait);
838 #endif /* CONFIG_PM */
839