xref: /linux/sound/core/pcm.c (revision 2ba9268dd603d23e17643437b2246acb6844953b)
1 /*
2  *  Digital Audio (PCM) abstract layer
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/slab.h>
24 #include <linux/module.h>
25 #include <linux/time.h>
26 #include <linux/mutex.h>
27 #include <linux/device.h>
28 #include <sound/core.h>
29 #include <sound/minors.h>
30 #include <sound/pcm.h>
31 #include <sound/control.h>
32 #include <sound/info.h>
33 
34 MODULE_AUTHOR("Jaroslav Kysela <perex@perex.cz>, Abramo Bagnara <abramo@alsa-project.org>");
35 MODULE_DESCRIPTION("Midlevel PCM code for ALSA.");
36 MODULE_LICENSE("GPL");
37 
38 static LIST_HEAD(snd_pcm_devices);
39 static LIST_HEAD(snd_pcm_notify_list);
40 static DEFINE_MUTEX(register_mutex);
41 
42 static int snd_pcm_free(struct snd_pcm *pcm);
43 static int snd_pcm_dev_free(struct snd_device *device);
44 static int snd_pcm_dev_register(struct snd_device *device);
45 static int snd_pcm_dev_disconnect(struct snd_device *device);
46 
47 static struct snd_pcm *snd_pcm_get(struct snd_card *card, int device)
48 {
49 	struct snd_pcm *pcm;
50 
51 	list_for_each_entry(pcm, &snd_pcm_devices, list) {
52 		if (pcm->internal)
53 			continue;
54 		if (pcm->card == card && pcm->device == device)
55 			return pcm;
56 	}
57 	return NULL;
58 }
59 
60 static int snd_pcm_next(struct snd_card *card, int device)
61 {
62 	struct snd_pcm *pcm;
63 
64 	list_for_each_entry(pcm, &snd_pcm_devices, list) {
65 		if (pcm->internal)
66 			continue;
67 		if (pcm->card == card && pcm->device > device)
68 			return pcm->device;
69 		else if (pcm->card->number > card->number)
70 			return -1;
71 	}
72 	return -1;
73 }
74 
75 static int snd_pcm_add(struct snd_pcm *newpcm)
76 {
77 	struct snd_pcm *pcm;
78 
79 	list_for_each_entry(pcm, &snd_pcm_devices, list) {
80 		if (pcm->card == newpcm->card && pcm->device == newpcm->device)
81 			return -EBUSY;
82 		if (pcm->card->number > newpcm->card->number ||
83 				(pcm->card == newpcm->card &&
84 				pcm->device > newpcm->device)) {
85 			list_add(&newpcm->list, pcm->list.prev);
86 			return 0;
87 		}
88 	}
89 	list_add_tail(&newpcm->list, &snd_pcm_devices);
90 	return 0;
91 }
92 
93 static int snd_pcm_control_ioctl(struct snd_card *card,
94 				 struct snd_ctl_file *control,
95 				 unsigned int cmd, unsigned long arg)
96 {
97 	switch (cmd) {
98 	case SNDRV_CTL_IOCTL_PCM_NEXT_DEVICE:
99 		{
100 			int device;
101 
102 			if (get_user(device, (int __user *)arg))
103 				return -EFAULT;
104 			mutex_lock(&register_mutex);
105 			device = snd_pcm_next(card, device);
106 			mutex_unlock(&register_mutex);
107 			if (put_user(device, (int __user *)arg))
108 				return -EFAULT;
109 			return 0;
110 		}
111 	case SNDRV_CTL_IOCTL_PCM_INFO:
112 		{
113 			struct snd_pcm_info __user *info;
114 			unsigned int device, subdevice;
115 			int stream;
116 			struct snd_pcm *pcm;
117 			struct snd_pcm_str *pstr;
118 			struct snd_pcm_substream *substream;
119 			int err;
120 
121 			info = (struct snd_pcm_info __user *)arg;
122 			if (get_user(device, &info->device))
123 				return -EFAULT;
124 			if (get_user(stream, &info->stream))
125 				return -EFAULT;
126 			if (stream < 0 || stream > 1)
127 				return -EINVAL;
128 			if (get_user(subdevice, &info->subdevice))
129 				return -EFAULT;
130 			mutex_lock(&register_mutex);
131 			pcm = snd_pcm_get(card, device);
132 			if (pcm == NULL) {
133 				err = -ENXIO;
134 				goto _error;
135 			}
136 			pstr = &pcm->streams[stream];
137 			if (pstr->substream_count == 0) {
138 				err = -ENOENT;
139 				goto _error;
140 			}
141 			if (subdevice >= pstr->substream_count) {
142 				err = -ENXIO;
143 				goto _error;
144 			}
145 			for (substream = pstr->substream; substream;
146 			     substream = substream->next)
147 				if (substream->number == (int)subdevice)
148 					break;
149 			if (substream == NULL) {
150 				err = -ENXIO;
151 				goto _error;
152 			}
153 			err = snd_pcm_info_user(substream, info);
154 		_error:
155 			mutex_unlock(&register_mutex);
156 			return err;
157 		}
158 	case SNDRV_CTL_IOCTL_PCM_PREFER_SUBDEVICE:
159 		{
160 			int val;
161 
162 			if (get_user(val, (int __user *)arg))
163 				return -EFAULT;
164 			control->preferred_subdevice[SND_CTL_SUBDEV_PCM] = val;
165 			return 0;
166 		}
167 	}
168 	return -ENOIOCTLCMD;
169 }
170 
171 #define FORMAT(v) [SNDRV_PCM_FORMAT_##v] = #v
172 
173 static char *snd_pcm_format_names[] = {
174 	FORMAT(S8),
175 	FORMAT(U8),
176 	FORMAT(S16_LE),
177 	FORMAT(S16_BE),
178 	FORMAT(U16_LE),
179 	FORMAT(U16_BE),
180 	FORMAT(S24_LE),
181 	FORMAT(S24_BE),
182 	FORMAT(U24_LE),
183 	FORMAT(U24_BE),
184 	FORMAT(S32_LE),
185 	FORMAT(S32_BE),
186 	FORMAT(U32_LE),
187 	FORMAT(U32_BE),
188 	FORMAT(FLOAT_LE),
189 	FORMAT(FLOAT_BE),
190 	FORMAT(FLOAT64_LE),
191 	FORMAT(FLOAT64_BE),
192 	FORMAT(IEC958_SUBFRAME_LE),
193 	FORMAT(IEC958_SUBFRAME_BE),
194 	FORMAT(MU_LAW),
195 	FORMAT(A_LAW),
196 	FORMAT(IMA_ADPCM),
197 	FORMAT(MPEG),
198 	FORMAT(GSM),
199 	FORMAT(SPECIAL),
200 	FORMAT(S24_3LE),
201 	FORMAT(S24_3BE),
202 	FORMAT(U24_3LE),
203 	FORMAT(U24_3BE),
204 	FORMAT(S20_3LE),
205 	FORMAT(S20_3BE),
206 	FORMAT(U20_3LE),
207 	FORMAT(U20_3BE),
208 	FORMAT(S18_3LE),
209 	FORMAT(S18_3BE),
210 	FORMAT(U18_3LE),
211 	FORMAT(U18_3BE),
212 	FORMAT(G723_24),
213 	FORMAT(G723_24_1B),
214 	FORMAT(G723_40),
215 	FORMAT(G723_40_1B),
216 	FORMAT(DSD_U8),
217 	FORMAT(DSD_U16_LE),
218 	FORMAT(DSD_U32_LE),
219 	FORMAT(DSD_U16_BE),
220 	FORMAT(DSD_U32_BE),
221 };
222 
223 /**
224  * snd_pcm_format_name - Return a name string for the given PCM format
225  * @format: PCM format
226  */
227 const char *snd_pcm_format_name(snd_pcm_format_t format)
228 {
229 	if ((__force unsigned int)format >= ARRAY_SIZE(snd_pcm_format_names))
230 		return "Unknown";
231 	return snd_pcm_format_names[(__force unsigned int)format];
232 }
233 EXPORT_SYMBOL_GPL(snd_pcm_format_name);
234 
235 #ifdef CONFIG_SND_VERBOSE_PROCFS
236 
237 #define STATE(v) [SNDRV_PCM_STATE_##v] = #v
238 #define STREAM(v) [SNDRV_PCM_STREAM_##v] = #v
239 #define READY(v) [SNDRV_PCM_READY_##v] = #v
240 #define XRUN(v) [SNDRV_PCM_XRUN_##v] = #v
241 #define SILENCE(v) [SNDRV_PCM_SILENCE_##v] = #v
242 #define TSTAMP(v) [SNDRV_PCM_TSTAMP_##v] = #v
243 #define ACCESS(v) [SNDRV_PCM_ACCESS_##v] = #v
244 #define START(v) [SNDRV_PCM_START_##v] = #v
245 #define SUBFORMAT(v) [SNDRV_PCM_SUBFORMAT_##v] = #v
246 
247 static char *snd_pcm_stream_names[] = {
248 	STREAM(PLAYBACK),
249 	STREAM(CAPTURE),
250 };
251 
252 static char *snd_pcm_state_names[] = {
253 	STATE(OPEN),
254 	STATE(SETUP),
255 	STATE(PREPARED),
256 	STATE(RUNNING),
257 	STATE(XRUN),
258 	STATE(DRAINING),
259 	STATE(PAUSED),
260 	STATE(SUSPENDED),
261 };
262 
263 static char *snd_pcm_access_names[] = {
264 	ACCESS(MMAP_INTERLEAVED),
265 	ACCESS(MMAP_NONINTERLEAVED),
266 	ACCESS(MMAP_COMPLEX),
267 	ACCESS(RW_INTERLEAVED),
268 	ACCESS(RW_NONINTERLEAVED),
269 };
270 
271 static char *snd_pcm_subformat_names[] = {
272 	SUBFORMAT(STD),
273 };
274 
275 static char *snd_pcm_tstamp_mode_names[] = {
276 	TSTAMP(NONE),
277 	TSTAMP(ENABLE),
278 };
279 
280 static const char *snd_pcm_stream_name(int stream)
281 {
282 	return snd_pcm_stream_names[stream];
283 }
284 
285 static const char *snd_pcm_access_name(snd_pcm_access_t access)
286 {
287 	return snd_pcm_access_names[(__force int)access];
288 }
289 
290 static const char *snd_pcm_subformat_name(snd_pcm_subformat_t subformat)
291 {
292 	return snd_pcm_subformat_names[(__force int)subformat];
293 }
294 
295 static const char *snd_pcm_tstamp_mode_name(int mode)
296 {
297 	return snd_pcm_tstamp_mode_names[mode];
298 }
299 
300 static const char *snd_pcm_state_name(snd_pcm_state_t state)
301 {
302 	return snd_pcm_state_names[(__force int)state];
303 }
304 
305 #if IS_ENABLED(CONFIG_SND_PCM_OSS)
306 #include <linux/soundcard.h>
307 
308 static const char *snd_pcm_oss_format_name(int format)
309 {
310 	switch (format) {
311 	case AFMT_MU_LAW:
312 		return "MU_LAW";
313 	case AFMT_A_LAW:
314 		return "A_LAW";
315 	case AFMT_IMA_ADPCM:
316 		return "IMA_ADPCM";
317 	case AFMT_U8:
318 		return "U8";
319 	case AFMT_S16_LE:
320 		return "S16_LE";
321 	case AFMT_S16_BE:
322 		return "S16_BE";
323 	case AFMT_S8:
324 		return "S8";
325 	case AFMT_U16_LE:
326 		return "U16_LE";
327 	case AFMT_U16_BE:
328 		return "U16_BE";
329 	case AFMT_MPEG:
330 		return "MPEG";
331 	default:
332 		return "unknown";
333 	}
334 }
335 #endif
336 
337 static void snd_pcm_proc_info_read(struct snd_pcm_substream *substream,
338 				   struct snd_info_buffer *buffer)
339 {
340 	struct snd_pcm_info *info;
341 	int err;
342 
343 	if (! substream)
344 		return;
345 
346 	info = kmalloc(sizeof(*info), GFP_KERNEL);
347 	if (! info) {
348 		pcm_dbg(substream->pcm,
349 			"snd_pcm_proc_info_read: cannot malloc\n");
350 		return;
351 	}
352 
353 	err = snd_pcm_info(substream, info);
354 	if (err < 0) {
355 		snd_iprintf(buffer, "error %d\n", err);
356 		kfree(info);
357 		return;
358 	}
359 	snd_iprintf(buffer, "card: %d\n", info->card);
360 	snd_iprintf(buffer, "device: %d\n", info->device);
361 	snd_iprintf(buffer, "subdevice: %d\n", info->subdevice);
362 	snd_iprintf(buffer, "stream: %s\n", snd_pcm_stream_name(info->stream));
363 	snd_iprintf(buffer, "id: %s\n", info->id);
364 	snd_iprintf(buffer, "name: %s\n", info->name);
365 	snd_iprintf(buffer, "subname: %s\n", info->subname);
366 	snd_iprintf(buffer, "class: %d\n", info->dev_class);
367 	snd_iprintf(buffer, "subclass: %d\n", info->dev_subclass);
368 	snd_iprintf(buffer, "subdevices_count: %d\n", info->subdevices_count);
369 	snd_iprintf(buffer, "subdevices_avail: %d\n", info->subdevices_avail);
370 	kfree(info);
371 }
372 
373 static void snd_pcm_stream_proc_info_read(struct snd_info_entry *entry,
374 					  struct snd_info_buffer *buffer)
375 {
376 	snd_pcm_proc_info_read(((struct snd_pcm_str *)entry->private_data)->substream,
377 			       buffer);
378 }
379 
380 static void snd_pcm_substream_proc_info_read(struct snd_info_entry *entry,
381 					     struct snd_info_buffer *buffer)
382 {
383 	snd_pcm_proc_info_read(entry->private_data, buffer);
384 }
385 
386 static void snd_pcm_substream_proc_hw_params_read(struct snd_info_entry *entry,
387 						  struct snd_info_buffer *buffer)
388 {
389 	struct snd_pcm_substream *substream = entry->private_data;
390 	struct snd_pcm_runtime *runtime;
391 
392 	mutex_lock(&substream->pcm->open_mutex);
393 	runtime = substream->runtime;
394 	if (!runtime) {
395 		snd_iprintf(buffer, "closed\n");
396 		goto unlock;
397 	}
398 	if (runtime->status->state == SNDRV_PCM_STATE_OPEN) {
399 		snd_iprintf(buffer, "no setup\n");
400 		goto unlock;
401 	}
402 	snd_iprintf(buffer, "access: %s\n", snd_pcm_access_name(runtime->access));
403 	snd_iprintf(buffer, "format: %s\n", snd_pcm_format_name(runtime->format));
404 	snd_iprintf(buffer, "subformat: %s\n", snd_pcm_subformat_name(runtime->subformat));
405 	snd_iprintf(buffer, "channels: %u\n", runtime->channels);
406 	snd_iprintf(buffer, "rate: %u (%u/%u)\n", runtime->rate, runtime->rate_num, runtime->rate_den);
407 	snd_iprintf(buffer, "period_size: %lu\n", runtime->period_size);
408 	snd_iprintf(buffer, "buffer_size: %lu\n", runtime->buffer_size);
409 #if IS_ENABLED(CONFIG_SND_PCM_OSS)
410 	if (substream->oss.oss) {
411 		snd_iprintf(buffer, "OSS format: %s\n", snd_pcm_oss_format_name(runtime->oss.format));
412 		snd_iprintf(buffer, "OSS channels: %u\n", runtime->oss.channels);
413 		snd_iprintf(buffer, "OSS rate: %u\n", runtime->oss.rate);
414 		snd_iprintf(buffer, "OSS period bytes: %lu\n", (unsigned long)runtime->oss.period_bytes);
415 		snd_iprintf(buffer, "OSS periods: %u\n", runtime->oss.periods);
416 		snd_iprintf(buffer, "OSS period frames: %lu\n", (unsigned long)runtime->oss.period_frames);
417 	}
418 #endif
419  unlock:
420 	mutex_unlock(&substream->pcm->open_mutex);
421 }
422 
423 static void snd_pcm_substream_proc_sw_params_read(struct snd_info_entry *entry,
424 						  struct snd_info_buffer *buffer)
425 {
426 	struct snd_pcm_substream *substream = entry->private_data;
427 	struct snd_pcm_runtime *runtime;
428 
429 	mutex_lock(&substream->pcm->open_mutex);
430 	runtime = substream->runtime;
431 	if (!runtime) {
432 		snd_iprintf(buffer, "closed\n");
433 		goto unlock;
434 	}
435 	if (runtime->status->state == SNDRV_PCM_STATE_OPEN) {
436 		snd_iprintf(buffer, "no setup\n");
437 		goto unlock;
438 	}
439 	snd_iprintf(buffer, "tstamp_mode: %s\n", snd_pcm_tstamp_mode_name(runtime->tstamp_mode));
440 	snd_iprintf(buffer, "period_step: %u\n", runtime->period_step);
441 	snd_iprintf(buffer, "avail_min: %lu\n", runtime->control->avail_min);
442 	snd_iprintf(buffer, "start_threshold: %lu\n", runtime->start_threshold);
443 	snd_iprintf(buffer, "stop_threshold: %lu\n", runtime->stop_threshold);
444 	snd_iprintf(buffer, "silence_threshold: %lu\n", runtime->silence_threshold);
445 	snd_iprintf(buffer, "silence_size: %lu\n", runtime->silence_size);
446 	snd_iprintf(buffer, "boundary: %lu\n", runtime->boundary);
447  unlock:
448 	mutex_unlock(&substream->pcm->open_mutex);
449 }
450 
451 static void snd_pcm_substream_proc_status_read(struct snd_info_entry *entry,
452 					       struct snd_info_buffer *buffer)
453 {
454 	struct snd_pcm_substream *substream = entry->private_data;
455 	struct snd_pcm_runtime *runtime;
456 	struct snd_pcm_status status;
457 	int err;
458 
459 	mutex_lock(&substream->pcm->open_mutex);
460 	runtime = substream->runtime;
461 	if (!runtime) {
462 		snd_iprintf(buffer, "closed\n");
463 		goto unlock;
464 	}
465 	memset(&status, 0, sizeof(status));
466 	err = snd_pcm_status(substream, &status);
467 	if (err < 0) {
468 		snd_iprintf(buffer, "error %d\n", err);
469 		goto unlock;
470 	}
471 	snd_iprintf(buffer, "state: %s\n", snd_pcm_state_name(status.state));
472 	snd_iprintf(buffer, "owner_pid   : %d\n", pid_vnr(substream->pid));
473 	snd_iprintf(buffer, "trigger_time: %ld.%09ld\n",
474 		status.trigger_tstamp.tv_sec, status.trigger_tstamp.tv_nsec);
475 	snd_iprintf(buffer, "tstamp      : %ld.%09ld\n",
476 		status.tstamp.tv_sec, status.tstamp.tv_nsec);
477 	snd_iprintf(buffer, "delay       : %ld\n", status.delay);
478 	snd_iprintf(buffer, "avail       : %ld\n", status.avail);
479 	snd_iprintf(buffer, "avail_max   : %ld\n", status.avail_max);
480 	snd_iprintf(buffer, "-----\n");
481 	snd_iprintf(buffer, "hw_ptr      : %ld\n", runtime->status->hw_ptr);
482 	snd_iprintf(buffer, "appl_ptr    : %ld\n", runtime->control->appl_ptr);
483  unlock:
484 	mutex_unlock(&substream->pcm->open_mutex);
485 }
486 
487 #ifdef CONFIG_SND_PCM_XRUN_DEBUG
488 static void snd_pcm_xrun_injection_write(struct snd_info_entry *entry,
489 					 struct snd_info_buffer *buffer)
490 {
491 	struct snd_pcm_substream *substream = entry->private_data;
492 	struct snd_pcm_runtime *runtime;
493 
494 	snd_pcm_stream_lock_irq(substream);
495 	runtime = substream->runtime;
496 	if (runtime && runtime->status->state == SNDRV_PCM_STATE_RUNNING)
497 		snd_pcm_stop(substream, SNDRV_PCM_STATE_XRUN);
498 	snd_pcm_stream_unlock_irq(substream);
499 }
500 
501 static void snd_pcm_xrun_debug_read(struct snd_info_entry *entry,
502 				    struct snd_info_buffer *buffer)
503 {
504 	struct snd_pcm_str *pstr = entry->private_data;
505 	snd_iprintf(buffer, "%d\n", pstr->xrun_debug);
506 }
507 
508 static void snd_pcm_xrun_debug_write(struct snd_info_entry *entry,
509 				     struct snd_info_buffer *buffer)
510 {
511 	struct snd_pcm_str *pstr = entry->private_data;
512 	char line[64];
513 	if (!snd_info_get_line(buffer, line, sizeof(line)))
514 		pstr->xrun_debug = simple_strtoul(line, NULL, 10);
515 }
516 #endif
517 
518 static int snd_pcm_stream_proc_init(struct snd_pcm_str *pstr)
519 {
520 	struct snd_pcm *pcm = pstr->pcm;
521 	struct snd_info_entry *entry;
522 	char name[16];
523 
524 	sprintf(name, "pcm%i%c", pcm->device,
525 		pstr->stream == SNDRV_PCM_STREAM_PLAYBACK ? 'p' : 'c');
526 	if ((entry = snd_info_create_card_entry(pcm->card, name, pcm->card->proc_root)) == NULL)
527 		return -ENOMEM;
528 	entry->mode = S_IFDIR | S_IRUGO | S_IXUGO;
529 	if (snd_info_register(entry) < 0) {
530 		snd_info_free_entry(entry);
531 		return -ENOMEM;
532 	}
533 	pstr->proc_root = entry;
534 
535 	if ((entry = snd_info_create_card_entry(pcm->card, "info", pstr->proc_root)) != NULL) {
536 		snd_info_set_text_ops(entry, pstr, snd_pcm_stream_proc_info_read);
537 		if (snd_info_register(entry) < 0) {
538 			snd_info_free_entry(entry);
539 			entry = NULL;
540 		}
541 	}
542 	pstr->proc_info_entry = entry;
543 
544 #ifdef CONFIG_SND_PCM_XRUN_DEBUG
545 	if ((entry = snd_info_create_card_entry(pcm->card, "xrun_debug",
546 						pstr->proc_root)) != NULL) {
547 		entry->c.text.read = snd_pcm_xrun_debug_read;
548 		entry->c.text.write = snd_pcm_xrun_debug_write;
549 		entry->mode |= S_IWUSR;
550 		entry->private_data = pstr;
551 		if (snd_info_register(entry) < 0) {
552 			snd_info_free_entry(entry);
553 			entry = NULL;
554 		}
555 	}
556 	pstr->proc_xrun_debug_entry = entry;
557 #endif
558 	return 0;
559 }
560 
561 static int snd_pcm_stream_proc_done(struct snd_pcm_str *pstr)
562 {
563 #ifdef CONFIG_SND_PCM_XRUN_DEBUG
564 	snd_info_free_entry(pstr->proc_xrun_debug_entry);
565 	pstr->proc_xrun_debug_entry = NULL;
566 #endif
567 	snd_info_free_entry(pstr->proc_info_entry);
568 	pstr->proc_info_entry = NULL;
569 	snd_info_free_entry(pstr->proc_root);
570 	pstr->proc_root = NULL;
571 	return 0;
572 }
573 
574 static int snd_pcm_substream_proc_init(struct snd_pcm_substream *substream)
575 {
576 	struct snd_info_entry *entry;
577 	struct snd_card *card;
578 	char name[16];
579 
580 	card = substream->pcm->card;
581 
582 	sprintf(name, "sub%i", substream->number);
583 	if ((entry = snd_info_create_card_entry(card, name, substream->pstr->proc_root)) == NULL)
584 		return -ENOMEM;
585 	entry->mode = S_IFDIR | S_IRUGO | S_IXUGO;
586 	if (snd_info_register(entry) < 0) {
587 		snd_info_free_entry(entry);
588 		return -ENOMEM;
589 	}
590 	substream->proc_root = entry;
591 
592 	if ((entry = snd_info_create_card_entry(card, "info", substream->proc_root)) != NULL) {
593 		snd_info_set_text_ops(entry, substream,
594 				      snd_pcm_substream_proc_info_read);
595 		if (snd_info_register(entry) < 0) {
596 			snd_info_free_entry(entry);
597 			entry = NULL;
598 		}
599 	}
600 	substream->proc_info_entry = entry;
601 
602 	if ((entry = snd_info_create_card_entry(card, "hw_params", substream->proc_root)) != NULL) {
603 		snd_info_set_text_ops(entry, substream,
604 				      snd_pcm_substream_proc_hw_params_read);
605 		if (snd_info_register(entry) < 0) {
606 			snd_info_free_entry(entry);
607 			entry = NULL;
608 		}
609 	}
610 	substream->proc_hw_params_entry = entry;
611 
612 	if ((entry = snd_info_create_card_entry(card, "sw_params", substream->proc_root)) != NULL) {
613 		snd_info_set_text_ops(entry, substream,
614 				      snd_pcm_substream_proc_sw_params_read);
615 		if (snd_info_register(entry) < 0) {
616 			snd_info_free_entry(entry);
617 			entry = NULL;
618 		}
619 	}
620 	substream->proc_sw_params_entry = entry;
621 
622 	if ((entry = snd_info_create_card_entry(card, "status", substream->proc_root)) != NULL) {
623 		snd_info_set_text_ops(entry, substream,
624 				      snd_pcm_substream_proc_status_read);
625 		if (snd_info_register(entry) < 0) {
626 			snd_info_free_entry(entry);
627 			entry = NULL;
628 		}
629 	}
630 	substream->proc_status_entry = entry;
631 
632 #ifdef CONFIG_SND_PCM_XRUN_DEBUG
633 	entry = snd_info_create_card_entry(card, "xrun_injection",
634 					   substream->proc_root);
635 	if (entry) {
636 		entry->private_data = substream;
637 		entry->c.text.read = NULL;
638 		entry->c.text.write = snd_pcm_xrun_injection_write;
639 		entry->mode = S_IFREG | S_IWUSR;
640 		if (snd_info_register(entry) < 0) {
641 			snd_info_free_entry(entry);
642 			entry = NULL;
643 		}
644 	}
645 	substream->proc_xrun_injection_entry = entry;
646 #endif /* CONFIG_SND_PCM_XRUN_DEBUG */
647 
648 	return 0;
649 }
650 
651 static int snd_pcm_substream_proc_done(struct snd_pcm_substream *substream)
652 {
653 	snd_info_free_entry(substream->proc_info_entry);
654 	substream->proc_info_entry = NULL;
655 	snd_info_free_entry(substream->proc_hw_params_entry);
656 	substream->proc_hw_params_entry = NULL;
657 	snd_info_free_entry(substream->proc_sw_params_entry);
658 	substream->proc_sw_params_entry = NULL;
659 	snd_info_free_entry(substream->proc_status_entry);
660 	substream->proc_status_entry = NULL;
661 #ifdef CONFIG_SND_PCM_XRUN_DEBUG
662 	snd_info_free_entry(substream->proc_xrun_injection_entry);
663 	substream->proc_xrun_injection_entry = NULL;
664 #endif
665 	snd_info_free_entry(substream->proc_root);
666 	substream->proc_root = NULL;
667 	return 0;
668 }
669 #else /* !CONFIG_SND_VERBOSE_PROCFS */
670 static inline int snd_pcm_stream_proc_init(struct snd_pcm_str *pstr) { return 0; }
671 static inline int snd_pcm_stream_proc_done(struct snd_pcm_str *pstr) { return 0; }
672 static inline int snd_pcm_substream_proc_init(struct snd_pcm_substream *substream) { return 0; }
673 static inline int snd_pcm_substream_proc_done(struct snd_pcm_substream *substream) { return 0; }
674 #endif /* CONFIG_SND_VERBOSE_PROCFS */
675 
676 static const struct attribute_group *pcm_dev_attr_groups[];
677 
678 /**
679  * snd_pcm_new_stream - create a new PCM stream
680  * @pcm: the pcm instance
681  * @stream: the stream direction, SNDRV_PCM_STREAM_XXX
682  * @substream_count: the number of substreams
683  *
684  * Creates a new stream for the pcm.
685  * The corresponding stream on the pcm must have been empty before
686  * calling this, i.e. zero must be given to the argument of
687  * snd_pcm_new().
688  *
689  * Return: Zero if successful, or a negative error code on failure.
690  */
691 int snd_pcm_new_stream(struct snd_pcm *pcm, int stream, int substream_count)
692 {
693 	int idx, err;
694 	struct snd_pcm_str *pstr = &pcm->streams[stream];
695 	struct snd_pcm_substream *substream, *prev;
696 
697 #if IS_ENABLED(CONFIG_SND_PCM_OSS)
698 	mutex_init(&pstr->oss.setup_mutex);
699 #endif
700 	pstr->stream = stream;
701 	pstr->pcm = pcm;
702 	pstr->substream_count = substream_count;
703 	if (!substream_count)
704 		return 0;
705 
706 	snd_device_initialize(&pstr->dev, pcm->card);
707 	pstr->dev.groups = pcm_dev_attr_groups;
708 	dev_set_name(&pstr->dev, "pcmC%iD%i%c", pcm->card->number, pcm->device,
709 		     stream == SNDRV_PCM_STREAM_PLAYBACK ? 'p' : 'c');
710 
711 	if (!pcm->internal) {
712 		err = snd_pcm_stream_proc_init(pstr);
713 		if (err < 0) {
714 			pcm_err(pcm, "Error in snd_pcm_stream_proc_init\n");
715 			return err;
716 		}
717 	}
718 	prev = NULL;
719 	for (idx = 0, prev = NULL; idx < substream_count; idx++) {
720 		substream = kzalloc(sizeof(*substream), GFP_KERNEL);
721 		if (substream == NULL) {
722 			pcm_err(pcm, "Cannot allocate PCM substream\n");
723 			return -ENOMEM;
724 		}
725 		substream->pcm = pcm;
726 		substream->pstr = pstr;
727 		substream->number = idx;
728 		substream->stream = stream;
729 		sprintf(substream->name, "subdevice #%i", idx);
730 		substream->buffer_bytes_max = UINT_MAX;
731 		if (prev == NULL)
732 			pstr->substream = substream;
733 		else
734 			prev->next = substream;
735 
736 		if (!pcm->internal) {
737 			err = snd_pcm_substream_proc_init(substream);
738 			if (err < 0) {
739 				pcm_err(pcm,
740 					"Error in snd_pcm_stream_proc_init\n");
741 				if (prev == NULL)
742 					pstr->substream = NULL;
743 				else
744 					prev->next = NULL;
745 				kfree(substream);
746 				return err;
747 			}
748 		}
749 		substream->group = &substream->self_group;
750 		spin_lock_init(&substream->self_group.lock);
751 		mutex_init(&substream->self_group.mutex);
752 		INIT_LIST_HEAD(&substream->self_group.substreams);
753 		list_add_tail(&substream->link_list, &substream->self_group.substreams);
754 		atomic_set(&substream->mmap_count, 0);
755 		prev = substream;
756 	}
757 	return 0;
758 }
759 EXPORT_SYMBOL(snd_pcm_new_stream);
760 
761 static int _snd_pcm_new(struct snd_card *card, const char *id, int device,
762 		int playback_count, int capture_count, bool internal,
763 		struct snd_pcm **rpcm)
764 {
765 	struct snd_pcm *pcm;
766 	int err;
767 	static struct snd_device_ops ops = {
768 		.dev_free = snd_pcm_dev_free,
769 		.dev_register =	snd_pcm_dev_register,
770 		.dev_disconnect = snd_pcm_dev_disconnect,
771 	};
772 
773 	if (snd_BUG_ON(!card))
774 		return -ENXIO;
775 	if (rpcm)
776 		*rpcm = NULL;
777 	pcm = kzalloc(sizeof(*pcm), GFP_KERNEL);
778 	if (pcm == NULL) {
779 		dev_err(card->dev, "Cannot allocate PCM\n");
780 		return -ENOMEM;
781 	}
782 	pcm->card = card;
783 	pcm->device = device;
784 	pcm->internal = internal;
785 	if (id)
786 		strlcpy(pcm->id, id, sizeof(pcm->id));
787 	if ((err = snd_pcm_new_stream(pcm, SNDRV_PCM_STREAM_PLAYBACK, playback_count)) < 0) {
788 		snd_pcm_free(pcm);
789 		return err;
790 	}
791 	if ((err = snd_pcm_new_stream(pcm, SNDRV_PCM_STREAM_CAPTURE, capture_count)) < 0) {
792 		snd_pcm_free(pcm);
793 		return err;
794 	}
795 	mutex_init(&pcm->open_mutex);
796 	init_waitqueue_head(&pcm->open_wait);
797 	if ((err = snd_device_new(card, SNDRV_DEV_PCM, pcm, &ops)) < 0) {
798 		snd_pcm_free(pcm);
799 		return err;
800 	}
801 	if (rpcm)
802 		*rpcm = pcm;
803 	return 0;
804 }
805 
806 /**
807  * snd_pcm_new - create a new PCM instance
808  * @card: the card instance
809  * @id: the id string
810  * @device: the device index (zero based)
811  * @playback_count: the number of substreams for playback
812  * @capture_count: the number of substreams for capture
813  * @rpcm: the pointer to store the new pcm instance
814  *
815  * Creates a new PCM instance.
816  *
817  * The pcm operators have to be set afterwards to the new instance
818  * via snd_pcm_set_ops().
819  *
820  * Return: Zero if successful, or a negative error code on failure.
821  */
822 int snd_pcm_new(struct snd_card *card, const char *id, int device,
823 		int playback_count, int capture_count, struct snd_pcm **rpcm)
824 {
825 	return _snd_pcm_new(card, id, device, playback_count, capture_count,
826 			false, rpcm);
827 }
828 EXPORT_SYMBOL(snd_pcm_new);
829 
830 /**
831  * snd_pcm_new_internal - create a new internal PCM instance
832  * @card: the card instance
833  * @id: the id string
834  * @device: the device index (zero based - shared with normal PCMs)
835  * @playback_count: the number of substreams for playback
836  * @capture_count: the number of substreams for capture
837  * @rpcm: the pointer to store the new pcm instance
838  *
839  * Creates a new internal PCM instance with no userspace device or procfs
840  * entries. This is used by ASoC Back End PCMs in order to create a PCM that
841  * will only be used internally by kernel drivers. i.e. it cannot be opened
842  * by userspace. It provides existing ASoC components drivers with a substream
843  * and access to any private data.
844  *
845  * The pcm operators have to be set afterwards to the new instance
846  * via snd_pcm_set_ops().
847  *
848  * Return: Zero if successful, or a negative error code on failure.
849  */
850 int snd_pcm_new_internal(struct snd_card *card, const char *id, int device,
851 	int playback_count, int capture_count,
852 	struct snd_pcm **rpcm)
853 {
854 	return _snd_pcm_new(card, id, device, playback_count, capture_count,
855 			true, rpcm);
856 }
857 EXPORT_SYMBOL(snd_pcm_new_internal);
858 
859 static void snd_pcm_free_stream(struct snd_pcm_str * pstr)
860 {
861 	struct snd_pcm_substream *substream, *substream_next;
862 #if IS_ENABLED(CONFIG_SND_PCM_OSS)
863 	struct snd_pcm_oss_setup *setup, *setupn;
864 #endif
865 	substream = pstr->substream;
866 	while (substream) {
867 		substream_next = substream->next;
868 		snd_pcm_timer_done(substream);
869 		snd_pcm_substream_proc_done(substream);
870 		kfree(substream);
871 		substream = substream_next;
872 	}
873 	snd_pcm_stream_proc_done(pstr);
874 #if IS_ENABLED(CONFIG_SND_PCM_OSS)
875 	for (setup = pstr->oss.setup_list; setup; setup = setupn) {
876 		setupn = setup->next;
877 		kfree(setup->task_name);
878 		kfree(setup);
879 	}
880 #endif
881 	if (pstr->substream_count)
882 		put_device(&pstr->dev);
883 }
884 
885 static int snd_pcm_free(struct snd_pcm *pcm)
886 {
887 	struct snd_pcm_notify *notify;
888 
889 	if (!pcm)
890 		return 0;
891 	list_for_each_entry(notify, &snd_pcm_notify_list, list) {
892 		notify->n_unregister(pcm);
893 	}
894 	if (pcm->private_free)
895 		pcm->private_free(pcm);
896 	snd_pcm_lib_preallocate_free_for_all(pcm);
897 	snd_pcm_free_stream(&pcm->streams[SNDRV_PCM_STREAM_PLAYBACK]);
898 	snd_pcm_free_stream(&pcm->streams[SNDRV_PCM_STREAM_CAPTURE]);
899 	kfree(pcm);
900 	return 0;
901 }
902 
903 static int snd_pcm_dev_free(struct snd_device *device)
904 {
905 	struct snd_pcm *pcm = device->device_data;
906 	return snd_pcm_free(pcm);
907 }
908 
909 int snd_pcm_attach_substream(struct snd_pcm *pcm, int stream,
910 			     struct file *file,
911 			     struct snd_pcm_substream **rsubstream)
912 {
913 	struct snd_pcm_str * pstr;
914 	struct snd_pcm_substream *substream;
915 	struct snd_pcm_runtime *runtime;
916 	struct snd_card *card;
917 	int prefer_subdevice;
918 	size_t size;
919 
920 	if (snd_BUG_ON(!pcm || !rsubstream))
921 		return -ENXIO;
922 	*rsubstream = NULL;
923 	pstr = &pcm->streams[stream];
924 	if (pstr->substream == NULL || pstr->substream_count == 0)
925 		return -ENODEV;
926 
927 	card = pcm->card;
928 	prefer_subdevice = snd_ctl_get_preferred_subdevice(card, SND_CTL_SUBDEV_PCM);
929 
930 	switch (stream) {
931 	case SNDRV_PCM_STREAM_PLAYBACK:
932 		if (pcm->info_flags & SNDRV_PCM_INFO_HALF_DUPLEX) {
933 			for (substream = pcm->streams[SNDRV_PCM_STREAM_CAPTURE].substream; substream; substream = substream->next) {
934 				if (SUBSTREAM_BUSY(substream))
935 					return -EAGAIN;
936 			}
937 		}
938 		break;
939 	case SNDRV_PCM_STREAM_CAPTURE:
940 		if (pcm->info_flags & SNDRV_PCM_INFO_HALF_DUPLEX) {
941 			for (substream = pcm->streams[SNDRV_PCM_STREAM_PLAYBACK].substream; substream; substream = substream->next) {
942 				if (SUBSTREAM_BUSY(substream))
943 					return -EAGAIN;
944 			}
945 		}
946 		break;
947 	default:
948 		return -EINVAL;
949 	}
950 
951 	if (file->f_flags & O_APPEND) {
952 		if (prefer_subdevice < 0) {
953 			if (pstr->substream_count > 1)
954 				return -EINVAL; /* must be unique */
955 			substream = pstr->substream;
956 		} else {
957 			for (substream = pstr->substream; substream;
958 			     substream = substream->next)
959 				if (substream->number == prefer_subdevice)
960 					break;
961 		}
962 		if (! substream)
963 			return -ENODEV;
964 		if (! SUBSTREAM_BUSY(substream))
965 			return -EBADFD;
966 		substream->ref_count++;
967 		*rsubstream = substream;
968 		return 0;
969 	}
970 
971 	if (prefer_subdevice >= 0) {
972 		for (substream = pstr->substream; substream; substream = substream->next)
973 			if (!SUBSTREAM_BUSY(substream) && substream->number == prefer_subdevice)
974 				goto __ok;
975 	}
976 	for (substream = pstr->substream; substream; substream = substream->next)
977 		if (!SUBSTREAM_BUSY(substream))
978 			break;
979       __ok:
980 	if (substream == NULL)
981 		return -EAGAIN;
982 
983 	runtime = kzalloc(sizeof(*runtime), GFP_KERNEL);
984 	if (runtime == NULL)
985 		return -ENOMEM;
986 
987 	size = PAGE_ALIGN(sizeof(struct snd_pcm_mmap_status));
988 	runtime->status = snd_malloc_pages(size, GFP_KERNEL);
989 	if (runtime->status == NULL) {
990 		kfree(runtime);
991 		return -ENOMEM;
992 	}
993 	memset((void*)runtime->status, 0, size);
994 
995 	size = PAGE_ALIGN(sizeof(struct snd_pcm_mmap_control));
996 	runtime->control = snd_malloc_pages(size, GFP_KERNEL);
997 	if (runtime->control == NULL) {
998 		snd_free_pages((void*)runtime->status,
999 			       PAGE_ALIGN(sizeof(struct snd_pcm_mmap_status)));
1000 		kfree(runtime);
1001 		return -ENOMEM;
1002 	}
1003 	memset((void*)runtime->control, 0, size);
1004 
1005 	init_waitqueue_head(&runtime->sleep);
1006 	init_waitqueue_head(&runtime->tsleep);
1007 
1008 	runtime->status->state = SNDRV_PCM_STATE_OPEN;
1009 
1010 	substream->runtime = runtime;
1011 	substream->private_data = pcm->private_data;
1012 	substream->ref_count = 1;
1013 	substream->f_flags = file->f_flags;
1014 	substream->pid = get_pid(task_pid(current));
1015 	pstr->substream_opened++;
1016 	*rsubstream = substream;
1017 	return 0;
1018 }
1019 
1020 void snd_pcm_detach_substream(struct snd_pcm_substream *substream)
1021 {
1022 	struct snd_pcm_runtime *runtime;
1023 
1024 	if (PCM_RUNTIME_CHECK(substream))
1025 		return;
1026 	runtime = substream->runtime;
1027 	if (runtime->private_free != NULL)
1028 		runtime->private_free(runtime);
1029 	snd_free_pages((void*)runtime->status,
1030 		       PAGE_ALIGN(sizeof(struct snd_pcm_mmap_status)));
1031 	snd_free_pages((void*)runtime->control,
1032 		       PAGE_ALIGN(sizeof(struct snd_pcm_mmap_control)));
1033 	kfree(runtime->hw_constraints.rules);
1034 #ifdef CONFIG_SND_PCM_XRUN_DEBUG
1035 	kfree(runtime->hwptr_log);
1036 #endif
1037 	kfree(runtime);
1038 	substream->runtime = NULL;
1039 	put_pid(substream->pid);
1040 	substream->pid = NULL;
1041 	substream->pstr->substream_opened--;
1042 }
1043 
1044 static ssize_t show_pcm_class(struct device *dev,
1045 			      struct device_attribute *attr, char *buf)
1046 {
1047 	struct snd_pcm *pcm;
1048 	const char *str;
1049 	static const char *strs[SNDRV_PCM_CLASS_LAST + 1] = {
1050 		[SNDRV_PCM_CLASS_GENERIC] = "generic",
1051 		[SNDRV_PCM_CLASS_MULTI] = "multi",
1052 		[SNDRV_PCM_CLASS_MODEM] = "modem",
1053 		[SNDRV_PCM_CLASS_DIGITIZER] = "digitizer",
1054 	};
1055 
1056 	if (! (pcm = dev_get_drvdata(dev)) ||
1057 	    pcm->dev_class > SNDRV_PCM_CLASS_LAST)
1058 		str = "none";
1059 	else
1060 		str = strs[pcm->dev_class];
1061         return snprintf(buf, PAGE_SIZE, "%s\n", str);
1062 }
1063 
1064 static DEVICE_ATTR(pcm_class, S_IRUGO, show_pcm_class, NULL);
1065 static struct attribute *pcm_dev_attrs[] = {
1066 	&dev_attr_pcm_class.attr,
1067 	NULL
1068 };
1069 
1070 static struct attribute_group pcm_dev_attr_group = {
1071 	.attrs	= pcm_dev_attrs,
1072 };
1073 
1074 static const struct attribute_group *pcm_dev_attr_groups[] = {
1075 	&pcm_dev_attr_group,
1076 	NULL
1077 };
1078 
1079 static int snd_pcm_dev_register(struct snd_device *device)
1080 {
1081 	int cidx, err;
1082 	struct snd_pcm_substream *substream;
1083 	struct snd_pcm_notify *notify;
1084 	struct snd_pcm *pcm;
1085 
1086 	if (snd_BUG_ON(!device || !device->device_data))
1087 		return -ENXIO;
1088 	pcm = device->device_data;
1089 	mutex_lock(&register_mutex);
1090 	err = snd_pcm_add(pcm);
1091 	if (err) {
1092 		mutex_unlock(&register_mutex);
1093 		return err;
1094 	}
1095 	for (cidx = 0; cidx < 2; cidx++) {
1096 		int devtype = -1;
1097 		if (pcm->streams[cidx].substream == NULL || pcm->internal)
1098 			continue;
1099 		switch (cidx) {
1100 		case SNDRV_PCM_STREAM_PLAYBACK:
1101 			devtype = SNDRV_DEVICE_TYPE_PCM_PLAYBACK;
1102 			break;
1103 		case SNDRV_PCM_STREAM_CAPTURE:
1104 			devtype = SNDRV_DEVICE_TYPE_PCM_CAPTURE;
1105 			break;
1106 		}
1107 		/* register pcm */
1108 		err = snd_register_device(devtype, pcm->card, pcm->device,
1109 					  &snd_pcm_f_ops[cidx], pcm,
1110 					  &pcm->streams[cidx].dev);
1111 		if (err < 0) {
1112 			list_del(&pcm->list);
1113 			mutex_unlock(&register_mutex);
1114 			return err;
1115 		}
1116 
1117 		for (substream = pcm->streams[cidx].substream; substream; substream = substream->next)
1118 			snd_pcm_timer_init(substream);
1119 	}
1120 
1121 	list_for_each_entry(notify, &snd_pcm_notify_list, list)
1122 		notify->n_register(pcm);
1123 
1124 	mutex_unlock(&register_mutex);
1125 	return 0;
1126 }
1127 
1128 static int snd_pcm_dev_disconnect(struct snd_device *device)
1129 {
1130 	struct snd_pcm *pcm = device->device_data;
1131 	struct snd_pcm_notify *notify;
1132 	struct snd_pcm_substream *substream;
1133 	int cidx;
1134 
1135 	mutex_lock(&register_mutex);
1136 	if (list_empty(&pcm->list))
1137 		goto unlock;
1138 
1139 	mutex_lock(&pcm->open_mutex);
1140 	wake_up(&pcm->open_wait);
1141 	list_del_init(&pcm->list);
1142 	for (cidx = 0; cidx < 2; cidx++)
1143 		for (substream = pcm->streams[cidx].substream; substream; substream = substream->next) {
1144 			snd_pcm_stream_lock_irq(substream);
1145 			if (substream->runtime) {
1146 				substream->runtime->status->state = SNDRV_PCM_STATE_DISCONNECTED;
1147 				wake_up(&substream->runtime->sleep);
1148 				wake_up(&substream->runtime->tsleep);
1149 			}
1150 			snd_pcm_stream_unlock_irq(substream);
1151 		}
1152 	list_for_each_entry(notify, &snd_pcm_notify_list, list) {
1153 		notify->n_disconnect(pcm);
1154 	}
1155 	for (cidx = 0; cidx < 2; cidx++) {
1156 		snd_unregister_device(&pcm->streams[cidx].dev);
1157 		if (pcm->streams[cidx].chmap_kctl) {
1158 			snd_ctl_remove(pcm->card, pcm->streams[cidx].chmap_kctl);
1159 			pcm->streams[cidx].chmap_kctl = NULL;
1160 		}
1161 	}
1162 	mutex_unlock(&pcm->open_mutex);
1163  unlock:
1164 	mutex_unlock(&register_mutex);
1165 	return 0;
1166 }
1167 
1168 /**
1169  * snd_pcm_notify - Add/remove the notify list
1170  * @notify: PCM notify list
1171  * @nfree: 0 = register, 1 = unregister
1172  *
1173  * This adds the given notifier to the global list so that the callback is
1174  * called for each registered PCM devices.  This exists only for PCM OSS
1175  * emulation, so far.
1176  */
1177 int snd_pcm_notify(struct snd_pcm_notify *notify, int nfree)
1178 {
1179 	struct snd_pcm *pcm;
1180 
1181 	if (snd_BUG_ON(!notify ||
1182 		       !notify->n_register ||
1183 		       !notify->n_unregister ||
1184 		       !notify->n_disconnect))
1185 		return -EINVAL;
1186 	mutex_lock(&register_mutex);
1187 	if (nfree) {
1188 		list_del(&notify->list);
1189 		list_for_each_entry(pcm, &snd_pcm_devices, list)
1190 			notify->n_unregister(pcm);
1191 	} else {
1192 		list_add_tail(&notify->list, &snd_pcm_notify_list);
1193 		list_for_each_entry(pcm, &snd_pcm_devices, list)
1194 			notify->n_register(pcm);
1195 	}
1196 	mutex_unlock(&register_mutex);
1197 	return 0;
1198 }
1199 EXPORT_SYMBOL(snd_pcm_notify);
1200 
1201 #ifdef CONFIG_PROC_FS
1202 /*
1203  *  Info interface
1204  */
1205 
1206 static void snd_pcm_proc_read(struct snd_info_entry *entry,
1207 			      struct snd_info_buffer *buffer)
1208 {
1209 	struct snd_pcm *pcm;
1210 
1211 	mutex_lock(&register_mutex);
1212 	list_for_each_entry(pcm, &snd_pcm_devices, list) {
1213 		snd_iprintf(buffer, "%02i-%02i: %s : %s",
1214 			    pcm->card->number, pcm->device, pcm->id, pcm->name);
1215 		if (pcm->streams[SNDRV_PCM_STREAM_PLAYBACK].substream)
1216 			snd_iprintf(buffer, " : playback %i",
1217 				    pcm->streams[SNDRV_PCM_STREAM_PLAYBACK].substream_count);
1218 		if (pcm->streams[SNDRV_PCM_STREAM_CAPTURE].substream)
1219 			snd_iprintf(buffer, " : capture %i",
1220 				    pcm->streams[SNDRV_PCM_STREAM_CAPTURE].substream_count);
1221 		snd_iprintf(buffer, "\n");
1222 	}
1223 	mutex_unlock(&register_mutex);
1224 }
1225 
1226 static struct snd_info_entry *snd_pcm_proc_entry;
1227 
1228 static void snd_pcm_proc_init(void)
1229 {
1230 	struct snd_info_entry *entry;
1231 
1232 	if ((entry = snd_info_create_module_entry(THIS_MODULE, "pcm", NULL)) != NULL) {
1233 		snd_info_set_text_ops(entry, NULL, snd_pcm_proc_read);
1234 		if (snd_info_register(entry) < 0) {
1235 			snd_info_free_entry(entry);
1236 			entry = NULL;
1237 		}
1238 	}
1239 	snd_pcm_proc_entry = entry;
1240 }
1241 
1242 static void snd_pcm_proc_done(void)
1243 {
1244 	snd_info_free_entry(snd_pcm_proc_entry);
1245 }
1246 
1247 #else /* !CONFIG_PROC_FS */
1248 #define snd_pcm_proc_init()
1249 #define snd_pcm_proc_done()
1250 #endif /* CONFIG_PROC_FS */
1251 
1252 
1253 /*
1254  *  ENTRY functions
1255  */
1256 
1257 static int __init alsa_pcm_init(void)
1258 {
1259 	snd_ctl_register_ioctl(snd_pcm_control_ioctl);
1260 	snd_ctl_register_ioctl_compat(snd_pcm_control_ioctl);
1261 	snd_pcm_proc_init();
1262 	return 0;
1263 }
1264 
1265 static void __exit alsa_pcm_exit(void)
1266 {
1267 	snd_ctl_unregister_ioctl(snd_pcm_control_ioctl);
1268 	snd_ctl_unregister_ioctl_compat(snd_pcm_control_ioctl);
1269 	snd_pcm_proc_done();
1270 }
1271 
1272 module_init(alsa_pcm_init)
1273 module_exit(alsa_pcm_exit)
1274