xref: /openbmc/linux/sound/core/init.c (revision 9d56dd3b083a3bec56e9da35ce07baca81030b03)
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 /* monitor files for graceful shutdown (hotplug) */
35 struct snd_monitor_file {
36 	struct file *file;
37 	const struct file_operations *disconnected_f_op;
38 	struct list_head shutdown_list;	/* still need to shutdown */
39 	struct list_head list;	/* link of monitor files */
40 };
41 
42 static DEFINE_SPINLOCK(shutdown_lock);
43 static LIST_HEAD(shutdown_files);
44 
45 static const struct file_operations snd_shutdown_f_ops;
46 
47 static unsigned int snd_cards_lock;	/* locked for registering/using */
48 struct snd_card *snd_cards[SNDRV_CARDS];
49 EXPORT_SYMBOL(snd_cards);
50 
51 static DEFINE_MUTEX(snd_card_mutex);
52 
53 static char *slots[SNDRV_CARDS];
54 module_param_array(slots, charp, NULL, 0444);
55 MODULE_PARM_DESC(slots, "Module names assigned to the slots.");
56 
57 /* return non-zero if the given index is reserved for the given
58  * module via slots option
59  */
60 static int module_slot_match(struct module *module, int idx)
61 {
62 	int match = 1;
63 #ifdef MODULE
64 	const char *s1, *s2;
65 
66 	if (!module || !module->name || !slots[idx])
67 		return 0;
68 
69 	s1 = module->name;
70 	s2 = slots[idx];
71 	if (*s2 == '!') {
72 		match = 0; /* negative match */
73 		s2++;
74 	}
75 	/* compare module name strings
76 	 * hyphens are handled as equivalent with underscore
77 	 */
78 	for (;;) {
79 		char c1 = *s1++;
80 		char c2 = *s2++;
81 		if (c1 == '-')
82 			c1 = '_';
83 		if (c2 == '-')
84 			c2 = '_';
85 		if (c1 != c2)
86 			return !match;
87 		if (!c1)
88 			break;
89 	}
90 #endif /* MODULE */
91 	return match;
92 }
93 
94 #if defined(CONFIG_SND_MIXER_OSS) || defined(CONFIG_SND_MIXER_OSS_MODULE)
95 int (*snd_mixer_oss_notify_callback)(struct snd_card *card, int free_flag);
96 EXPORT_SYMBOL(snd_mixer_oss_notify_callback);
97 #endif
98 
99 #ifdef CONFIG_PROC_FS
100 static void snd_card_id_read(struct snd_info_entry *entry,
101 			     struct snd_info_buffer *buffer)
102 {
103 	snd_iprintf(buffer, "%s\n", entry->card->id);
104 }
105 
106 static inline int init_info_for_card(struct snd_card *card)
107 {
108 	int err;
109 	struct snd_info_entry *entry;
110 
111 	if ((err = snd_info_card_register(card)) < 0) {
112 		snd_printd("unable to create card info\n");
113 		return err;
114 	}
115 	if ((entry = snd_info_create_card_entry(card, "id", card->proc_root)) == NULL) {
116 		snd_printd("unable to create card entry\n");
117 		return err;
118 	}
119 	entry->c.text.read = snd_card_id_read;
120 	if (snd_info_register(entry) < 0) {
121 		snd_info_free_entry(entry);
122 		entry = NULL;
123 	}
124 	card->proc_id = entry;
125 	return 0;
126 }
127 #else /* !CONFIG_PROC_FS */
128 #define init_info_for_card(card)
129 #endif
130 
131 /**
132  *  snd_card_create - create and initialize a soundcard structure
133  *  @idx: card index (address) [0 ... (SNDRV_CARDS-1)]
134  *  @xid: card identification (ASCII string)
135  *  @module: top level module for locking
136  *  @extra_size: allocate this extra size after the main soundcard structure
137  *  @card_ret: the pointer to store the created card instance
138  *
139  *  Creates and initializes a soundcard structure.
140  *
141  *  The function allocates snd_card instance via kzalloc with the given
142  *  space for the driver to use freely.  The allocated struct is stored
143  *  in the given card_ret pointer.
144  *
145  *  Returns zero if successful or a negative error code.
146  */
147 int snd_card_create(int idx, const char *xid,
148 		    struct module *module, int extra_size,
149 		    struct snd_card **card_ret)
150 {
151 	struct snd_card *card;
152 	int err, idx2;
153 
154 	if (snd_BUG_ON(!card_ret))
155 		return -EINVAL;
156 	*card_ret = NULL;
157 
158 	if (extra_size < 0)
159 		extra_size = 0;
160 	card = kzalloc(sizeof(*card) + extra_size, GFP_KERNEL);
161 	if (!card)
162 		return -ENOMEM;
163 	if (xid)
164 		strlcpy(card->id, xid, sizeof(card->id));
165 	err = 0;
166 	mutex_lock(&snd_card_mutex);
167 	if (idx < 0) {
168 		for (idx2 = 0; idx2 < SNDRV_CARDS; idx2++)
169 			/* idx == -1 == 0xffff means: take any free slot */
170 			if (~snd_cards_lock & idx & 1<<idx2) {
171 				if (module_slot_match(module, idx2)) {
172 					idx = idx2;
173 					break;
174 				}
175 			}
176 	}
177 	if (idx < 0) {
178 		for (idx2 = 0; idx2 < SNDRV_CARDS; idx2++)
179 			/* idx == -1 == 0xffff means: take any free slot */
180 			if (~snd_cards_lock & idx & 1<<idx2) {
181 				if (!slots[idx2] || !*slots[idx2]) {
182 					idx = idx2;
183 					break;
184 				}
185 			}
186 	}
187 	if (idx < 0)
188 		err = -ENODEV;
189 	else if (idx < snd_ecards_limit) {
190 		if (snd_cards_lock & (1 << idx))
191 			err = -EBUSY;	/* invalid */
192 	} else if (idx >= SNDRV_CARDS)
193 		err = -ENODEV;
194 	if (err < 0) {
195 		mutex_unlock(&snd_card_mutex);
196 		snd_printk(KERN_ERR "cannot find the slot for index %d (range 0-%i), error: %d\n",
197 			 idx, snd_ecards_limit - 1, err);
198 		goto __error;
199 	}
200 	snd_cards_lock |= 1 << idx;		/* lock it */
201 	if (idx >= snd_ecards_limit)
202 		snd_ecards_limit = idx + 1; /* increase the limit */
203 	mutex_unlock(&snd_card_mutex);
204 	card->number = idx;
205 	card->module = module;
206 	INIT_LIST_HEAD(&card->devices);
207 	init_rwsem(&card->controls_rwsem);
208 	rwlock_init(&card->ctl_files_rwlock);
209 	INIT_LIST_HEAD(&card->controls);
210 	INIT_LIST_HEAD(&card->ctl_files);
211 	spin_lock_init(&card->files_lock);
212 	INIT_LIST_HEAD(&card->files_list);
213 	init_waitqueue_head(&card->shutdown_sleep);
214 #ifdef CONFIG_PM
215 	mutex_init(&card->power_lock);
216 	init_waitqueue_head(&card->power_sleep);
217 #endif
218 	/* the control interface cannot be accessed from the user space until */
219 	/* snd_cards_bitmask and snd_cards are set with snd_card_register */
220 	err = snd_ctl_create(card);
221 	if (err < 0) {
222 		snd_printk(KERN_ERR "unable to register control minors\n");
223 		goto __error;
224 	}
225 	err = snd_info_card_create(card);
226 	if (err < 0) {
227 		snd_printk(KERN_ERR "unable to create card info\n");
228 		goto __error_ctl;
229 	}
230 	if (extra_size > 0)
231 		card->private_data = (char *)card + sizeof(struct snd_card);
232 	*card_ret = card;
233 	return 0;
234 
235       __error_ctl:
236 	snd_device_free_all(card, SNDRV_DEV_CMD_PRE);
237       __error:
238 	kfree(card);
239   	return err;
240 }
241 EXPORT_SYMBOL(snd_card_create);
242 
243 /* return non-zero if a card is already locked */
244 int snd_card_locked(int card)
245 {
246 	int locked;
247 
248 	mutex_lock(&snd_card_mutex);
249 	locked = snd_cards_lock & (1 << card);
250 	mutex_unlock(&snd_card_mutex);
251 	return locked;
252 }
253 
254 static loff_t snd_disconnect_llseek(struct file *file, loff_t offset, int orig)
255 {
256 	return -ENODEV;
257 }
258 
259 static ssize_t snd_disconnect_read(struct file *file, char __user *buf,
260 				   size_t count, loff_t *offset)
261 {
262 	return -ENODEV;
263 }
264 
265 static ssize_t snd_disconnect_write(struct file *file, const char __user *buf,
266 				    size_t count, loff_t *offset)
267 {
268 	return -ENODEV;
269 }
270 
271 static int snd_disconnect_release(struct inode *inode, struct file *file)
272 {
273 	struct snd_monitor_file *df = NULL, *_df;
274 
275 	spin_lock(&shutdown_lock);
276 	list_for_each_entry(_df, &shutdown_files, shutdown_list) {
277 		if (_df->file == file) {
278 			df = _df;
279 			list_del_init(&df->shutdown_list);
280 			break;
281 		}
282 	}
283 	spin_unlock(&shutdown_lock);
284 
285 	if (likely(df)) {
286 		if ((file->f_flags & FASYNC) && df->disconnected_f_op->fasync)
287 			df->disconnected_f_op->fasync(-1, file, 0);
288 		return df->disconnected_f_op->release(inode, file);
289 	}
290 
291 	panic("%s(%p, %p) failed!", __func__, inode, file);
292 }
293 
294 static unsigned int snd_disconnect_poll(struct file * file, poll_table * wait)
295 {
296 	return POLLERR | POLLNVAL;
297 }
298 
299 static long snd_disconnect_ioctl(struct file *file,
300 				 unsigned int cmd, unsigned long arg)
301 {
302 	return -ENODEV;
303 }
304 
305 static int snd_disconnect_mmap(struct file *file, struct vm_area_struct *vma)
306 {
307 	return -ENODEV;
308 }
309 
310 static int snd_disconnect_fasync(int fd, struct file *file, int on)
311 {
312 	return -ENODEV;
313 }
314 
315 static const struct file_operations snd_shutdown_f_ops =
316 {
317 	.owner = 	THIS_MODULE,
318 	.llseek =	snd_disconnect_llseek,
319 	.read = 	snd_disconnect_read,
320 	.write =	snd_disconnect_write,
321 	.release =	snd_disconnect_release,
322 	.poll =		snd_disconnect_poll,
323 	.unlocked_ioctl = snd_disconnect_ioctl,
324 #ifdef CONFIG_COMPAT
325 	.compat_ioctl = snd_disconnect_ioctl,
326 #endif
327 	.mmap =		snd_disconnect_mmap,
328 	.fasync =	snd_disconnect_fasync
329 };
330 
331 /**
332  *  snd_card_disconnect - disconnect all APIs from the file-operations (user space)
333  *  @card: soundcard structure
334  *
335  *  Disconnects all APIs from the file-operations (user space).
336  *
337  *  Returns zero, otherwise a negative error code.
338  *
339  *  Note: The current implementation replaces all active file->f_op with special
340  *        dummy file operations (they do nothing except release).
341  */
342 int snd_card_disconnect(struct snd_card *card)
343 {
344 	struct snd_monitor_file *mfile;
345 	struct file *file;
346 	int err;
347 
348 	if (!card)
349 		return -EINVAL;
350 
351 	spin_lock(&card->files_lock);
352 	if (card->shutdown) {
353 		spin_unlock(&card->files_lock);
354 		return 0;
355 	}
356 	card->shutdown = 1;
357 	spin_unlock(&card->files_lock);
358 
359 	/* phase 1: disable fops (user space) operations for ALSA API */
360 	mutex_lock(&snd_card_mutex);
361 	snd_cards[card->number] = NULL;
362 	snd_cards_lock &= ~(1 << card->number);
363 	mutex_unlock(&snd_card_mutex);
364 
365 	/* phase 2: replace file->f_op with special dummy operations */
366 
367 	spin_lock(&card->files_lock);
368 	list_for_each_entry(mfile, &card->files_list, list) {
369 		file = mfile->file;
370 
371 		/* it's critical part, use endless loop */
372 		/* we have no room to fail */
373 		mfile->disconnected_f_op = mfile->file->f_op;
374 
375 		spin_lock(&shutdown_lock);
376 		list_add(&mfile->shutdown_list, &shutdown_files);
377 		spin_unlock(&shutdown_lock);
378 
379 		mfile->file->f_op = &snd_shutdown_f_ops;
380 		fops_get(mfile->file->f_op);
381 	}
382 	spin_unlock(&card->files_lock);
383 
384 	/* phase 3: notify all connected devices about disconnection */
385 	/* at this point, they cannot respond to any calls except release() */
386 
387 #if defined(CONFIG_SND_MIXER_OSS) || defined(CONFIG_SND_MIXER_OSS_MODULE)
388 	if (snd_mixer_oss_notify_callback)
389 		snd_mixer_oss_notify_callback(card, SND_MIXER_OSS_NOTIFY_DISCONNECT);
390 #endif
391 
392 	/* notify all devices that we are disconnected */
393 	err = snd_device_disconnect_all(card);
394 	if (err < 0)
395 		snd_printk(KERN_ERR "not all devices for card %i can be disconnected\n", card->number);
396 
397 	snd_info_card_disconnect(card);
398 #ifndef CONFIG_SYSFS_DEPRECATED
399 	if (card->card_dev) {
400 		device_unregister(card->card_dev);
401 		card->card_dev = NULL;
402 	}
403 #endif
404 #ifdef CONFIG_PM
405 	wake_up(&card->power_sleep);
406 #endif
407 	return 0;
408 }
409 
410 EXPORT_SYMBOL(snd_card_disconnect);
411 
412 /**
413  *  snd_card_free - frees given soundcard structure
414  *  @card: soundcard structure
415  *
416  *  This function releases the soundcard structure and the all assigned
417  *  devices automatically.  That is, you don't have to release the devices
418  *  by yourself.
419  *
420  *  Returns zero. Frees all associated devices and frees the control
421  *  interface associated to given soundcard.
422  */
423 static int snd_card_do_free(struct snd_card *card)
424 {
425 #if defined(CONFIG_SND_MIXER_OSS) || defined(CONFIG_SND_MIXER_OSS_MODULE)
426 	if (snd_mixer_oss_notify_callback)
427 		snd_mixer_oss_notify_callback(card, SND_MIXER_OSS_NOTIFY_FREE);
428 #endif
429 	if (snd_device_free_all(card, SNDRV_DEV_CMD_PRE) < 0) {
430 		snd_printk(KERN_ERR "unable to free all devices (pre)\n");
431 		/* Fatal, but this situation should never occur */
432 	}
433 	if (snd_device_free_all(card, SNDRV_DEV_CMD_NORMAL) < 0) {
434 		snd_printk(KERN_ERR "unable to free all devices (normal)\n");
435 		/* Fatal, but this situation should never occur */
436 	}
437 	if (snd_device_free_all(card, SNDRV_DEV_CMD_POST) < 0) {
438 		snd_printk(KERN_ERR "unable to free all devices (post)\n");
439 		/* Fatal, but this situation should never occur */
440 	}
441 	if (card->private_free)
442 		card->private_free(card);
443 	snd_info_free_entry(card->proc_id);
444 	if (snd_info_card_free(card) < 0) {
445 		snd_printk(KERN_WARNING "unable to free card info\n");
446 		/* Not fatal error */
447 	}
448 	kfree(card);
449 	return 0;
450 }
451 
452 int snd_card_free_when_closed(struct snd_card *card)
453 {
454 	int free_now = 0;
455 	int ret = snd_card_disconnect(card);
456 	if (ret)
457 		return ret;
458 
459 	spin_lock(&card->files_lock);
460 	if (list_empty(&card->files_list))
461 		free_now = 1;
462 	else
463 		card->free_on_last_close = 1;
464 	spin_unlock(&card->files_lock);
465 
466 	if (free_now)
467 		snd_card_do_free(card);
468 	return 0;
469 }
470 
471 EXPORT_SYMBOL(snd_card_free_when_closed);
472 
473 int snd_card_free(struct snd_card *card)
474 {
475 	int ret = snd_card_disconnect(card);
476 	if (ret)
477 		return ret;
478 
479 	/* wait, until all devices are ready for the free operation */
480 	wait_event(card->shutdown_sleep, list_empty(&card->files_list));
481 	snd_card_do_free(card);
482 	return 0;
483 }
484 
485 EXPORT_SYMBOL(snd_card_free);
486 
487 static void snd_card_set_id_no_lock(struct snd_card *card, const char *nid)
488 {
489 	int i, len, idx_flag = 0, loops = SNDRV_CARDS;
490 	const char *spos, *src;
491 	char *id;
492 
493 	if (nid == NULL) {
494 		id = card->shortname;
495 		spos = src = id;
496 		while (*id != '\0') {
497 			if (*id == ' ')
498 				spos = id + 1;
499 			id++;
500 		}
501 	} else {
502 		spos = src = nid;
503 	}
504 	id = card->id;
505 	while (*spos != '\0' && !isalnum(*spos))
506 		spos++;
507 	if (isdigit(*spos))
508 		*id++ = isalpha(src[0]) ? src[0] : 'D';
509 	while (*spos != '\0' && (size_t)(id - card->id) < sizeof(card->id) - 1) {
510 		if (isalnum(*spos))
511 			*id++ = *spos;
512 		spos++;
513 	}
514 	*id = '\0';
515 
516 	id = card->id;
517 
518 	if (*id == '\0')
519 		strcpy(id, "default");
520 
521 	while (1) {
522 	      	if (loops-- == 0) {
523 			snd_printk(KERN_ERR "unable to set card id (%s)\n", id);
524       			strcpy(card->id, card->proc_root->name);
525       			return;
526       		}
527 	      	if (!snd_info_check_reserved_words(id))
528       			goto __change;
529 		for (i = 0; i < snd_ecards_limit; i++) {
530 			if (snd_cards[i] && !strcmp(snd_cards[i]->id, id))
531 				goto __change;
532 		}
533 		break;
534 
535 	      __change:
536 		len = strlen(id);
537 		if (idx_flag) {
538 			if (id[len-1] != '9')
539 				id[len-1]++;
540 			else
541 				id[len-1] = 'A';
542 		} else if ((size_t)len <= sizeof(card->id) - 3) {
543 			strcat(id, "_1");
544 			idx_flag++;
545 		} else {
546 			spos = id + len - 2;
547 			if ((size_t)len <= sizeof(card->id) - 2)
548 				spos++;
549 			*(char *)spos++ = '_';
550 			*(char *)spos++ = '1';
551 			*(char *)spos++ = '\0';
552 			idx_flag++;
553 		}
554 	}
555 }
556 
557 /**
558  *  snd_card_set_id - set card identification name
559  *  @card: soundcard structure
560  *  @nid: new identification string
561  *
562  *  This function sets the card identification and checks for name
563  *  collisions.
564  */
565 void snd_card_set_id(struct snd_card *card, const char *nid)
566 {
567 	/* check if user specified own card->id */
568 	if (card->id[0] != '\0')
569 		return;
570 	mutex_lock(&snd_card_mutex);
571 	snd_card_set_id_no_lock(card, nid);
572 	mutex_unlock(&snd_card_mutex);
573 }
574 EXPORT_SYMBOL(snd_card_set_id);
575 
576 #ifndef CONFIG_SYSFS_DEPRECATED
577 static ssize_t
578 card_id_show_attr(struct device *dev,
579 		  struct device_attribute *attr, char *buf)
580 {
581 	struct snd_card *card = dev_get_drvdata(dev);
582 	return snprintf(buf, PAGE_SIZE, "%s\n", card ? card->id : "(null)");
583 }
584 
585 static ssize_t
586 card_id_store_attr(struct device *dev, struct device_attribute *attr,
587 		   const char *buf, size_t count)
588 {
589 	struct snd_card *card = dev_get_drvdata(dev);
590 	char buf1[sizeof(card->id)];
591 	size_t copy = count > sizeof(card->id) - 1 ?
592 					sizeof(card->id) - 1 : count;
593 	size_t idx;
594 	int c;
595 
596 	for (idx = 0; idx < copy; idx++) {
597 		c = buf[idx];
598 		if (!isalnum(c) && c != '_' && c != '-')
599 			return -EINVAL;
600 	}
601 	memcpy(buf1, buf, copy);
602 	buf1[copy] = '\0';
603 	mutex_lock(&snd_card_mutex);
604 	if (!snd_info_check_reserved_words(buf1)) {
605 	     __exist:
606 		mutex_unlock(&snd_card_mutex);
607 		return -EEXIST;
608 	}
609 	for (idx = 0; idx < snd_ecards_limit; idx++) {
610 		if (snd_cards[idx] && !strcmp(snd_cards[idx]->id, buf1))
611 			goto __exist;
612 	}
613 	strcpy(card->id, buf1);
614 	snd_info_card_id_change(card);
615 	mutex_unlock(&snd_card_mutex);
616 
617 	return count;
618 }
619 
620 static struct device_attribute card_id_attrs =
621 	__ATTR(id, S_IRUGO | S_IWUSR, card_id_show_attr, card_id_store_attr);
622 
623 static ssize_t
624 card_number_show_attr(struct device *dev,
625 		     struct device_attribute *attr, char *buf)
626 {
627 	struct snd_card *card = dev_get_drvdata(dev);
628 	return snprintf(buf, PAGE_SIZE, "%i\n", card ? card->number : -1);
629 }
630 
631 static struct device_attribute card_number_attrs =
632 	__ATTR(number, S_IRUGO, card_number_show_attr, NULL);
633 #endif /* CONFIG_SYSFS_DEPRECATED */
634 
635 /**
636  *  snd_card_register - register the soundcard
637  *  @card: soundcard structure
638  *
639  *  This function registers all the devices assigned to the soundcard.
640  *  Until calling this, the ALSA control interface is blocked from the
641  *  external accesses.  Thus, you should call this function at the end
642  *  of the initialization of the card.
643  *
644  *  Returns zero otherwise a negative error code if the registrain failed.
645  */
646 int snd_card_register(struct snd_card *card)
647 {
648 	int err;
649 
650 	if (snd_BUG_ON(!card))
651 		return -EINVAL;
652 #ifndef CONFIG_SYSFS_DEPRECATED
653 	if (!card->card_dev) {
654 		card->card_dev = device_create(sound_class, card->dev,
655 					       MKDEV(0, 0), card,
656 					       "card%i", card->number);
657 		if (IS_ERR(card->card_dev))
658 			card->card_dev = NULL;
659 	}
660 #endif
661 	if ((err = snd_device_register_all(card)) < 0)
662 		return err;
663 	mutex_lock(&snd_card_mutex);
664 	if (snd_cards[card->number]) {
665 		/* already registered */
666 		mutex_unlock(&snd_card_mutex);
667 		return 0;
668 	}
669 	snd_card_set_id_no_lock(card, card->id[0] == '\0' ? NULL : card->id);
670 	snd_cards[card->number] = card;
671 	mutex_unlock(&snd_card_mutex);
672 	init_info_for_card(card);
673 #if defined(CONFIG_SND_MIXER_OSS) || defined(CONFIG_SND_MIXER_OSS_MODULE)
674 	if (snd_mixer_oss_notify_callback)
675 		snd_mixer_oss_notify_callback(card, SND_MIXER_OSS_NOTIFY_REGISTER);
676 #endif
677 #ifndef CONFIG_SYSFS_DEPRECATED
678 	if (card->card_dev) {
679 		err = device_create_file(card->card_dev, &card_id_attrs);
680 		if (err < 0)
681 			return err;
682 		err = device_create_file(card->card_dev, &card_number_attrs);
683 		if (err < 0)
684 			return err;
685 	}
686 #endif
687 	return 0;
688 }
689 
690 EXPORT_SYMBOL(snd_card_register);
691 
692 #ifdef CONFIG_PROC_FS
693 static struct snd_info_entry *snd_card_info_entry;
694 
695 static void snd_card_info_read(struct snd_info_entry *entry,
696 			       struct snd_info_buffer *buffer)
697 {
698 	int idx, count;
699 	struct snd_card *card;
700 
701 	for (idx = count = 0; idx < SNDRV_CARDS; idx++) {
702 		mutex_lock(&snd_card_mutex);
703 		if ((card = snd_cards[idx]) != NULL) {
704 			count++;
705 			snd_iprintf(buffer, "%2i [%-15s]: %s - %s\n",
706 					idx,
707 					card->id,
708 					card->driver,
709 					card->shortname);
710 			snd_iprintf(buffer, "                      %s\n",
711 					card->longname);
712 		}
713 		mutex_unlock(&snd_card_mutex);
714 	}
715 	if (!count)
716 		snd_iprintf(buffer, "--- no soundcards ---\n");
717 }
718 
719 #ifdef CONFIG_SND_OSSEMUL
720 
721 void snd_card_info_read_oss(struct snd_info_buffer *buffer)
722 {
723 	int idx, count;
724 	struct snd_card *card;
725 
726 	for (idx = count = 0; idx < SNDRV_CARDS; idx++) {
727 		mutex_lock(&snd_card_mutex);
728 		if ((card = snd_cards[idx]) != NULL) {
729 			count++;
730 			snd_iprintf(buffer, "%s\n", card->longname);
731 		}
732 		mutex_unlock(&snd_card_mutex);
733 	}
734 	if (!count) {
735 		snd_iprintf(buffer, "--- no soundcards ---\n");
736 	}
737 }
738 
739 #endif
740 
741 #ifdef MODULE
742 static struct snd_info_entry *snd_card_module_info_entry;
743 static void snd_card_module_info_read(struct snd_info_entry *entry,
744 				      struct snd_info_buffer *buffer)
745 {
746 	int idx;
747 	struct snd_card *card;
748 
749 	for (idx = 0; idx < SNDRV_CARDS; idx++) {
750 		mutex_lock(&snd_card_mutex);
751 		if ((card = snd_cards[idx]) != NULL)
752 			snd_iprintf(buffer, "%2i %s\n",
753 				    idx, card->module->name);
754 		mutex_unlock(&snd_card_mutex);
755 	}
756 }
757 #endif
758 
759 int __init snd_card_info_init(void)
760 {
761 	struct snd_info_entry *entry;
762 
763 	entry = snd_info_create_module_entry(THIS_MODULE, "cards", NULL);
764 	if (! entry)
765 		return -ENOMEM;
766 	entry->c.text.read = snd_card_info_read;
767 	if (snd_info_register(entry) < 0) {
768 		snd_info_free_entry(entry);
769 		return -ENOMEM;
770 	}
771 	snd_card_info_entry = entry;
772 
773 #ifdef MODULE
774 	entry = snd_info_create_module_entry(THIS_MODULE, "modules", NULL);
775 	if (entry) {
776 		entry->c.text.read = snd_card_module_info_read;
777 		if (snd_info_register(entry) < 0)
778 			snd_info_free_entry(entry);
779 		else
780 			snd_card_module_info_entry = entry;
781 	}
782 #endif
783 
784 	return 0;
785 }
786 
787 int __exit snd_card_info_done(void)
788 {
789 	snd_info_free_entry(snd_card_info_entry);
790 #ifdef MODULE
791 	snd_info_free_entry(snd_card_module_info_entry);
792 #endif
793 	return 0;
794 }
795 
796 #endif /* CONFIG_PROC_FS */
797 
798 /**
799  *  snd_component_add - add a component string
800  *  @card: soundcard structure
801  *  @component: the component id string
802  *
803  *  This function adds the component id string to the supported list.
804  *  The component can be referred from the alsa-lib.
805  *
806  *  Returns zero otherwise a negative error code.
807  */
808 
809 int snd_component_add(struct snd_card *card, const char *component)
810 {
811 	char *ptr;
812 	int len = strlen(component);
813 
814 	ptr = strstr(card->components, component);
815 	if (ptr != NULL) {
816 		if (ptr[len] == '\0' || ptr[len] == ' ')	/* already there */
817 			return 1;
818 	}
819 	if (strlen(card->components) + 1 + len + 1 > sizeof(card->components)) {
820 		snd_BUG();
821 		return -ENOMEM;
822 	}
823 	if (card->components[0] != '\0')
824 		strcat(card->components, " ");
825 	strcat(card->components, component);
826 	return 0;
827 }
828 
829 EXPORT_SYMBOL(snd_component_add);
830 
831 /**
832  *  snd_card_file_add - add the file to the file list of the card
833  *  @card: soundcard structure
834  *  @file: file pointer
835  *
836  *  This function adds the file to the file linked-list of the card.
837  *  This linked-list is used to keep tracking the connection state,
838  *  and to avoid the release of busy resources by hotplug.
839  *
840  *  Returns zero or a negative error code.
841  */
842 int snd_card_file_add(struct snd_card *card, struct file *file)
843 {
844 	struct snd_monitor_file *mfile;
845 
846 	mfile = kmalloc(sizeof(*mfile), GFP_KERNEL);
847 	if (mfile == NULL)
848 		return -ENOMEM;
849 	mfile->file = file;
850 	mfile->disconnected_f_op = NULL;
851 	spin_lock(&card->files_lock);
852 	if (card->shutdown) {
853 		spin_unlock(&card->files_lock);
854 		kfree(mfile);
855 		return -ENODEV;
856 	}
857 	list_add(&mfile->list, &card->files_list);
858 	spin_unlock(&card->files_lock);
859 	return 0;
860 }
861 
862 EXPORT_SYMBOL(snd_card_file_add);
863 
864 /**
865  *  snd_card_file_remove - remove the file from the file list
866  *  @card: soundcard structure
867  *  @file: file pointer
868  *
869  *  This function removes the file formerly added to the card via
870  *  snd_card_file_add() function.
871  *  If all files are removed and snd_card_free_when_closed() was
872  *  called beforehand, it processes the pending release of
873  *  resources.
874  *
875  *  Returns zero or a negative error code.
876  */
877 int snd_card_file_remove(struct snd_card *card, struct file *file)
878 {
879 	struct snd_monitor_file *mfile, *found = NULL;
880 	int last_close = 0;
881 
882 	spin_lock(&card->files_lock);
883 	list_for_each_entry(mfile, &card->files_list, list) {
884 		if (mfile->file == file) {
885 			list_del(&mfile->list);
886 			if (mfile->disconnected_f_op)
887 				fops_put(mfile->disconnected_f_op);
888 			found = mfile;
889 			break;
890 		}
891 	}
892 	if (list_empty(&card->files_list))
893 		last_close = 1;
894 	spin_unlock(&card->files_lock);
895 	if (last_close) {
896 		wake_up(&card->shutdown_sleep);
897 		if (card->free_on_last_close)
898 			snd_card_do_free(card);
899 	}
900 	if (!found) {
901 		snd_printk(KERN_ERR "ALSA card file remove problem (%p)\n", file);
902 		return -ENOENT;
903 	}
904 	kfree(found);
905 	return 0;
906 }
907 
908 EXPORT_SYMBOL(snd_card_file_remove);
909 
910 #ifdef CONFIG_PM
911 /**
912  *  snd_power_wait - wait until the power-state is changed.
913  *  @card: soundcard structure
914  *  @power_state: expected power state
915  *
916  *  Waits until the power-state is changed.
917  *
918  *  Note: the power lock must be active before call.
919  */
920 int snd_power_wait(struct snd_card *card, unsigned int power_state)
921 {
922 	wait_queue_t wait;
923 	int result = 0;
924 
925 	/* fastpath */
926 	if (snd_power_get_state(card) == power_state)
927 		return 0;
928 	init_waitqueue_entry(&wait, current);
929 	add_wait_queue(&card->power_sleep, &wait);
930 	while (1) {
931 		if (card->shutdown) {
932 			result = -ENODEV;
933 			break;
934 		}
935 		if (snd_power_get_state(card) == power_state)
936 			break;
937 		set_current_state(TASK_UNINTERRUPTIBLE);
938 		snd_power_unlock(card);
939 		schedule_timeout(30 * HZ);
940 		snd_power_lock(card);
941 	}
942 	remove_wait_queue(&card->power_sleep, &wait);
943 	return result;
944 }
945 
946 EXPORT_SYMBOL(snd_power_wait);
947 #endif /* CONFIG_PM */
948