xref: /linux/sound/core/pcm.c (revision e0a2e73e501c77037c8756137e87b12c7c3c9793)
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/timer.h>
32 #include <sound/control.h>
33 #include <sound/info.h>
34 
35 #include "pcm_local.h"
36 
37 MODULE_AUTHOR("Jaroslav Kysela <perex@perex.cz>, Abramo Bagnara <abramo@alsa-project.org>");
38 MODULE_DESCRIPTION("Midlevel PCM code for ALSA.");
39 MODULE_LICENSE("GPL");
40 
41 static LIST_HEAD(snd_pcm_devices);
42 static DEFINE_MUTEX(register_mutex);
43 #if IS_ENABLED(CONFIG_SND_PCM_OSS)
44 static LIST_HEAD(snd_pcm_notify_list);
45 #endif
46 
47 static int snd_pcm_free(struct snd_pcm *pcm);
48 static int snd_pcm_dev_free(struct snd_device *device);
49 static int snd_pcm_dev_register(struct snd_device *device);
50 static int snd_pcm_dev_disconnect(struct snd_device *device);
51 
52 static struct snd_pcm *snd_pcm_get(struct snd_card *card, int device)
53 {
54 	struct snd_pcm *pcm;
55 
56 	list_for_each_entry(pcm, &snd_pcm_devices, list) {
57 		if (pcm->card == card && pcm->device == device)
58 			return pcm;
59 	}
60 	return NULL;
61 }
62 
63 static int snd_pcm_next(struct snd_card *card, int device)
64 {
65 	struct snd_pcm *pcm;
66 
67 	list_for_each_entry(pcm, &snd_pcm_devices, list) {
68 		if (pcm->card == card && pcm->device > device)
69 			return pcm->device;
70 		else if (pcm->card->number > card->number)
71 			return -1;
72 	}
73 	return -1;
74 }
75 
76 static int snd_pcm_add(struct snd_pcm *newpcm)
77 {
78 	struct snd_pcm *pcm;
79 
80 	if (newpcm->internal)
81 		return 0;
82 
83 	list_for_each_entry(pcm, &snd_pcm_devices, list) {
84 		if (pcm->card == newpcm->card && pcm->device == newpcm->device)
85 			return -EBUSY;
86 		if (pcm->card->number > newpcm->card->number ||
87 				(pcm->card == newpcm->card &&
88 				pcm->device > newpcm->device)) {
89 			list_add(&newpcm->list, pcm->list.prev);
90 			return 0;
91 		}
92 	}
93 	list_add_tail(&newpcm->list, &snd_pcm_devices);
94 	return 0;
95 }
96 
97 static int snd_pcm_control_ioctl(struct snd_card *card,
98 				 struct snd_ctl_file *control,
99 				 unsigned int cmd, unsigned long arg)
100 {
101 	switch (cmd) {
102 	case SNDRV_CTL_IOCTL_PCM_NEXT_DEVICE:
103 		{
104 			int device;
105 
106 			if (get_user(device, (int __user *)arg))
107 				return -EFAULT;
108 			mutex_lock(&register_mutex);
109 			device = snd_pcm_next(card, device);
110 			mutex_unlock(&register_mutex);
111 			if (put_user(device, (int __user *)arg))
112 				return -EFAULT;
113 			return 0;
114 		}
115 	case SNDRV_CTL_IOCTL_PCM_INFO:
116 		{
117 			struct snd_pcm_info __user *info;
118 			unsigned int device, subdevice;
119 			int stream;
120 			struct snd_pcm *pcm;
121 			struct snd_pcm_str *pstr;
122 			struct snd_pcm_substream *substream;
123 			int err;
124 
125 			info = (struct snd_pcm_info __user *)arg;
126 			if (get_user(device, &info->device))
127 				return -EFAULT;
128 			if (get_user(stream, &info->stream))
129 				return -EFAULT;
130 			if (stream < 0 || stream > 1)
131 				return -EINVAL;
132 			if (get_user(subdevice, &info->subdevice))
133 				return -EFAULT;
134 			mutex_lock(&register_mutex);
135 			pcm = snd_pcm_get(card, device);
136 			if (pcm == NULL) {
137 				err = -ENXIO;
138 				goto _error;
139 			}
140 			pstr = &pcm->streams[stream];
141 			if (pstr->substream_count == 0) {
142 				err = -ENOENT;
143 				goto _error;
144 			}
145 			if (subdevice >= pstr->substream_count) {
146 				err = -ENXIO;
147 				goto _error;
148 			}
149 			for (substream = pstr->substream; substream;
150 			     substream = substream->next)
151 				if (substream->number == (int)subdevice)
152 					break;
153 			if (substream == NULL) {
154 				err = -ENXIO;
155 				goto _error;
156 			}
157 			mutex_lock(&pcm->open_mutex);
158 			err = snd_pcm_info_user(substream, info);
159 			mutex_unlock(&pcm->open_mutex);
160 		_error:
161 			mutex_unlock(&register_mutex);
162 			return err;
163 		}
164 	case SNDRV_CTL_IOCTL_PCM_PREFER_SUBDEVICE:
165 		{
166 			int val;
167 
168 			if (get_user(val, (int __user *)arg))
169 				return -EFAULT;
170 			control->preferred_subdevice[SND_CTL_SUBDEV_PCM] = val;
171 			return 0;
172 		}
173 	}
174 	return -ENOIOCTLCMD;
175 }
176 
177 #define FORMAT(v) [SNDRV_PCM_FORMAT_##v] = #v
178 
179 static char *snd_pcm_format_names[] = {
180 	FORMAT(S8),
181 	FORMAT(U8),
182 	FORMAT(S16_LE),
183 	FORMAT(S16_BE),
184 	FORMAT(U16_LE),
185 	FORMAT(U16_BE),
186 	FORMAT(S24_LE),
187 	FORMAT(S24_BE),
188 	FORMAT(U24_LE),
189 	FORMAT(U24_BE),
190 	FORMAT(S32_LE),
191 	FORMAT(S32_BE),
192 	FORMAT(U32_LE),
193 	FORMAT(U32_BE),
194 	FORMAT(FLOAT_LE),
195 	FORMAT(FLOAT_BE),
196 	FORMAT(FLOAT64_LE),
197 	FORMAT(FLOAT64_BE),
198 	FORMAT(IEC958_SUBFRAME_LE),
199 	FORMAT(IEC958_SUBFRAME_BE),
200 	FORMAT(MU_LAW),
201 	FORMAT(A_LAW),
202 	FORMAT(IMA_ADPCM),
203 	FORMAT(MPEG),
204 	FORMAT(GSM),
205 	FORMAT(SPECIAL),
206 	FORMAT(S24_3LE),
207 	FORMAT(S24_3BE),
208 	FORMAT(U24_3LE),
209 	FORMAT(U24_3BE),
210 	FORMAT(S20_3LE),
211 	FORMAT(S20_3BE),
212 	FORMAT(U20_3LE),
213 	FORMAT(U20_3BE),
214 	FORMAT(S18_3LE),
215 	FORMAT(S18_3BE),
216 	FORMAT(U18_3LE),
217 	FORMAT(U18_3BE),
218 	FORMAT(G723_24),
219 	FORMAT(G723_24_1B),
220 	FORMAT(G723_40),
221 	FORMAT(G723_40_1B),
222 	FORMAT(DSD_U8),
223 	FORMAT(DSD_U16_LE),
224 	FORMAT(DSD_U32_LE),
225 	FORMAT(DSD_U16_BE),
226 	FORMAT(DSD_U32_BE),
227 };
228 
229 /**
230  * snd_pcm_format_name - Return a name string for the given PCM format
231  * @format: PCM format
232  */
233 const char *snd_pcm_format_name(snd_pcm_format_t format)
234 {
235 	if ((__force unsigned int)format >= ARRAY_SIZE(snd_pcm_format_names))
236 		return "Unknown";
237 	return snd_pcm_format_names[(__force unsigned int)format];
238 }
239 EXPORT_SYMBOL_GPL(snd_pcm_format_name);
240 
241 #ifdef CONFIG_SND_VERBOSE_PROCFS
242 
243 #define STATE(v) [SNDRV_PCM_STATE_##v] = #v
244 #define STREAM(v) [SNDRV_PCM_STREAM_##v] = #v
245 #define READY(v) [SNDRV_PCM_READY_##v] = #v
246 #define XRUN(v) [SNDRV_PCM_XRUN_##v] = #v
247 #define SILENCE(v) [SNDRV_PCM_SILENCE_##v] = #v
248 #define TSTAMP(v) [SNDRV_PCM_TSTAMP_##v] = #v
249 #define ACCESS(v) [SNDRV_PCM_ACCESS_##v] = #v
250 #define START(v) [SNDRV_PCM_START_##v] = #v
251 #define SUBFORMAT(v) [SNDRV_PCM_SUBFORMAT_##v] = #v
252 
253 static char *snd_pcm_stream_names[] = {
254 	STREAM(PLAYBACK),
255 	STREAM(CAPTURE),
256 };
257 
258 static char *snd_pcm_state_names[] = {
259 	STATE(OPEN),
260 	STATE(SETUP),
261 	STATE(PREPARED),
262 	STATE(RUNNING),
263 	STATE(XRUN),
264 	STATE(DRAINING),
265 	STATE(PAUSED),
266 	STATE(SUSPENDED),
267 };
268 
269 static char *snd_pcm_access_names[] = {
270 	ACCESS(MMAP_INTERLEAVED),
271 	ACCESS(MMAP_NONINTERLEAVED),
272 	ACCESS(MMAP_COMPLEX),
273 	ACCESS(RW_INTERLEAVED),
274 	ACCESS(RW_NONINTERLEAVED),
275 };
276 
277 static char *snd_pcm_subformat_names[] = {
278 	SUBFORMAT(STD),
279 };
280 
281 static char *snd_pcm_tstamp_mode_names[] = {
282 	TSTAMP(NONE),
283 	TSTAMP(ENABLE),
284 };
285 
286 static const char *snd_pcm_stream_name(int stream)
287 {
288 	return snd_pcm_stream_names[stream];
289 }
290 
291 static const char *snd_pcm_access_name(snd_pcm_access_t access)
292 {
293 	return snd_pcm_access_names[(__force int)access];
294 }
295 
296 static const char *snd_pcm_subformat_name(snd_pcm_subformat_t subformat)
297 {
298 	return snd_pcm_subformat_names[(__force int)subformat];
299 }
300 
301 static const char *snd_pcm_tstamp_mode_name(int mode)
302 {
303 	return snd_pcm_tstamp_mode_names[mode];
304 }
305 
306 static const char *snd_pcm_state_name(snd_pcm_state_t state)
307 {
308 	return snd_pcm_state_names[(__force int)state];
309 }
310 
311 #if IS_ENABLED(CONFIG_SND_PCM_OSS)
312 #include <linux/soundcard.h>
313 
314 static const char *snd_pcm_oss_format_name(int format)
315 {
316 	switch (format) {
317 	case AFMT_MU_LAW:
318 		return "MU_LAW";
319 	case AFMT_A_LAW:
320 		return "A_LAW";
321 	case AFMT_IMA_ADPCM:
322 		return "IMA_ADPCM";
323 	case AFMT_U8:
324 		return "U8";
325 	case AFMT_S16_LE:
326 		return "S16_LE";
327 	case AFMT_S16_BE:
328 		return "S16_BE";
329 	case AFMT_S8:
330 		return "S8";
331 	case AFMT_U16_LE:
332 		return "U16_LE";
333 	case AFMT_U16_BE:
334 		return "U16_BE";
335 	case AFMT_MPEG:
336 		return "MPEG";
337 	default:
338 		return "unknown";
339 	}
340 }
341 #endif
342 
343 static void snd_pcm_proc_info_read(struct snd_pcm_substream *substream,
344 				   struct snd_info_buffer *buffer)
345 {
346 	struct snd_pcm_info *info;
347 	int err;
348 
349 	if (! substream)
350 		return;
351 
352 	info = kmalloc(sizeof(*info), GFP_KERNEL);
353 	if (!info)
354 		return;
355 
356 	err = snd_pcm_info(substream, info);
357 	if (err < 0) {
358 		snd_iprintf(buffer, "error %d\n", err);
359 		kfree(info);
360 		return;
361 	}
362 	snd_iprintf(buffer, "card: %d\n", info->card);
363 	snd_iprintf(buffer, "device: %d\n", info->device);
364 	snd_iprintf(buffer, "subdevice: %d\n", info->subdevice);
365 	snd_iprintf(buffer, "stream: %s\n", snd_pcm_stream_name(info->stream));
366 	snd_iprintf(buffer, "id: %s\n", info->id);
367 	snd_iprintf(buffer, "name: %s\n", info->name);
368 	snd_iprintf(buffer, "subname: %s\n", info->subname);
369 	snd_iprintf(buffer, "class: %d\n", info->dev_class);
370 	snd_iprintf(buffer, "subclass: %d\n", info->dev_subclass);
371 	snd_iprintf(buffer, "subdevices_count: %d\n", info->subdevices_count);
372 	snd_iprintf(buffer, "subdevices_avail: %d\n", info->subdevices_avail);
373 	kfree(info);
374 }
375 
376 static void snd_pcm_stream_proc_info_read(struct snd_info_entry *entry,
377 					  struct snd_info_buffer *buffer)
378 {
379 	snd_pcm_proc_info_read(((struct snd_pcm_str *)entry->private_data)->substream,
380 			       buffer);
381 }
382 
383 static void snd_pcm_substream_proc_info_read(struct snd_info_entry *entry,
384 					     struct snd_info_buffer *buffer)
385 {
386 	snd_pcm_proc_info_read(entry->private_data, buffer);
387 }
388 
389 static void snd_pcm_substream_proc_hw_params_read(struct snd_info_entry *entry,
390 						  struct snd_info_buffer *buffer)
391 {
392 	struct snd_pcm_substream *substream = entry->private_data;
393 	struct snd_pcm_runtime *runtime;
394 
395 	mutex_lock(&substream->pcm->open_mutex);
396 	runtime = substream->runtime;
397 	if (!runtime) {
398 		snd_iprintf(buffer, "closed\n");
399 		goto unlock;
400 	}
401 	if (runtime->status->state == SNDRV_PCM_STATE_OPEN) {
402 		snd_iprintf(buffer, "no setup\n");
403 		goto unlock;
404 	}
405 	snd_iprintf(buffer, "access: %s\n", snd_pcm_access_name(runtime->access));
406 	snd_iprintf(buffer, "format: %s\n", snd_pcm_format_name(runtime->format));
407 	snd_iprintf(buffer, "subformat: %s\n", snd_pcm_subformat_name(runtime->subformat));
408 	snd_iprintf(buffer, "channels: %u\n", runtime->channels);
409 	snd_iprintf(buffer, "rate: %u (%u/%u)\n", runtime->rate, runtime->rate_num, runtime->rate_den);
410 	snd_iprintf(buffer, "period_size: %lu\n", runtime->period_size);
411 	snd_iprintf(buffer, "buffer_size: %lu\n", runtime->buffer_size);
412 #if IS_ENABLED(CONFIG_SND_PCM_OSS)
413 	if (substream->oss.oss) {
414 		snd_iprintf(buffer, "OSS format: %s\n", snd_pcm_oss_format_name(runtime->oss.format));
415 		snd_iprintf(buffer, "OSS channels: %u\n", runtime->oss.channels);
416 		snd_iprintf(buffer, "OSS rate: %u\n", runtime->oss.rate);
417 		snd_iprintf(buffer, "OSS period bytes: %lu\n", (unsigned long)runtime->oss.period_bytes);
418 		snd_iprintf(buffer, "OSS periods: %u\n", runtime->oss.periods);
419 		snd_iprintf(buffer, "OSS period frames: %lu\n", (unsigned long)runtime->oss.period_frames);
420 	}
421 #endif
422  unlock:
423 	mutex_unlock(&substream->pcm->open_mutex);
424 }
425 
426 static void snd_pcm_substream_proc_sw_params_read(struct snd_info_entry *entry,
427 						  struct snd_info_buffer *buffer)
428 {
429 	struct snd_pcm_substream *substream = entry->private_data;
430 	struct snd_pcm_runtime *runtime;
431 
432 	mutex_lock(&substream->pcm->open_mutex);
433 	runtime = substream->runtime;
434 	if (!runtime) {
435 		snd_iprintf(buffer, "closed\n");
436 		goto unlock;
437 	}
438 	if (runtime->status->state == SNDRV_PCM_STATE_OPEN) {
439 		snd_iprintf(buffer, "no setup\n");
440 		goto unlock;
441 	}
442 	snd_iprintf(buffer, "tstamp_mode: %s\n", snd_pcm_tstamp_mode_name(runtime->tstamp_mode));
443 	snd_iprintf(buffer, "period_step: %u\n", runtime->period_step);
444 	snd_iprintf(buffer, "avail_min: %lu\n", runtime->control->avail_min);
445 	snd_iprintf(buffer, "start_threshold: %lu\n", runtime->start_threshold);
446 	snd_iprintf(buffer, "stop_threshold: %lu\n", runtime->stop_threshold);
447 	snd_iprintf(buffer, "silence_threshold: %lu\n", runtime->silence_threshold);
448 	snd_iprintf(buffer, "silence_size: %lu\n", runtime->silence_size);
449 	snd_iprintf(buffer, "boundary: %lu\n", runtime->boundary);
450  unlock:
451 	mutex_unlock(&substream->pcm->open_mutex);
452 }
453 
454 static void snd_pcm_substream_proc_status_read(struct snd_info_entry *entry,
455 					       struct snd_info_buffer *buffer)
456 {
457 	struct snd_pcm_substream *substream = entry->private_data;
458 	struct snd_pcm_runtime *runtime;
459 	struct snd_pcm_status status;
460 	int err;
461 
462 	mutex_lock(&substream->pcm->open_mutex);
463 	runtime = substream->runtime;
464 	if (!runtime) {
465 		snd_iprintf(buffer, "closed\n");
466 		goto unlock;
467 	}
468 	memset(&status, 0, sizeof(status));
469 	err = snd_pcm_status(substream, &status);
470 	if (err < 0) {
471 		snd_iprintf(buffer, "error %d\n", err);
472 		goto unlock;
473 	}
474 	snd_iprintf(buffer, "state: %s\n", snd_pcm_state_name(status.state));
475 	snd_iprintf(buffer, "owner_pid   : %d\n", pid_vnr(substream->pid));
476 	snd_iprintf(buffer, "trigger_time: %ld.%09ld\n",
477 		status.trigger_tstamp.tv_sec, status.trigger_tstamp.tv_nsec);
478 	snd_iprintf(buffer, "tstamp      : %ld.%09ld\n",
479 		status.tstamp.tv_sec, status.tstamp.tv_nsec);
480 	snd_iprintf(buffer, "delay       : %ld\n", status.delay);
481 	snd_iprintf(buffer, "avail       : %ld\n", status.avail);
482 	snd_iprintf(buffer, "avail_max   : %ld\n", status.avail_max);
483 	snd_iprintf(buffer, "-----\n");
484 	snd_iprintf(buffer, "hw_ptr      : %ld\n", runtime->status->hw_ptr);
485 	snd_iprintf(buffer, "appl_ptr    : %ld\n", runtime->control->appl_ptr);
486  unlock:
487 	mutex_unlock(&substream->pcm->open_mutex);
488 }
489 
490 #ifdef CONFIG_SND_PCM_XRUN_DEBUG
491 static void snd_pcm_xrun_injection_write(struct snd_info_entry *entry,
492 					 struct snd_info_buffer *buffer)
493 {
494 	struct snd_pcm_substream *substream = entry->private_data;
495 
496 	snd_pcm_stop_xrun(substream);
497 }
498 
499 static void snd_pcm_xrun_debug_read(struct snd_info_entry *entry,
500 				    struct snd_info_buffer *buffer)
501 {
502 	struct snd_pcm_str *pstr = entry->private_data;
503 	snd_iprintf(buffer, "%d\n", pstr->xrun_debug);
504 }
505 
506 static void snd_pcm_xrun_debug_write(struct snd_info_entry *entry,
507 				     struct snd_info_buffer *buffer)
508 {
509 	struct snd_pcm_str *pstr = entry->private_data;
510 	char line[64];
511 	if (!snd_info_get_line(buffer, line, sizeof(line)))
512 		pstr->xrun_debug = simple_strtoul(line, NULL, 10);
513 }
514 #endif
515 
516 static int snd_pcm_stream_proc_init(struct snd_pcm_str *pstr)
517 {
518 	struct snd_pcm *pcm = pstr->pcm;
519 	struct snd_info_entry *entry;
520 	char name[16];
521 
522 	sprintf(name, "pcm%i%c", pcm->device,
523 		pstr->stream == SNDRV_PCM_STREAM_PLAYBACK ? 'p' : 'c');
524 	entry = snd_info_create_card_entry(pcm->card, name,
525 					   pcm->card->proc_root);
526 	if (!entry)
527 		return -ENOMEM;
528 	entry->mode = S_IFDIR | 0555;
529 	if (snd_info_register(entry) < 0) {
530 		snd_info_free_entry(entry);
531 		return -ENOMEM;
532 	}
533 	pstr->proc_root = entry;
534 	entry = snd_info_create_card_entry(pcm->card, "info", pstr->proc_root);
535 	if (entry) {
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 	entry = snd_info_create_card_entry(pcm->card, "xrun_debug",
546 					   pstr->proc_root);
547 	if (entry) {
548 		entry->c.text.read = snd_pcm_xrun_debug_read;
549 		entry->c.text.write = snd_pcm_xrun_debug_write;
550 		entry->mode |= 0200;
551 		entry->private_data = pstr;
552 		if (snd_info_register(entry) < 0) {
553 			snd_info_free_entry(entry);
554 			entry = NULL;
555 		}
556 	}
557 	pstr->proc_xrun_debug_entry = entry;
558 #endif
559 	return 0;
560 }
561 
562 static int snd_pcm_stream_proc_done(struct snd_pcm_str *pstr)
563 {
564 #ifdef CONFIG_SND_PCM_XRUN_DEBUG
565 	snd_info_free_entry(pstr->proc_xrun_debug_entry);
566 	pstr->proc_xrun_debug_entry = NULL;
567 #endif
568 	snd_info_free_entry(pstr->proc_info_entry);
569 	pstr->proc_info_entry = NULL;
570 	snd_info_free_entry(pstr->proc_root);
571 	pstr->proc_root = NULL;
572 	return 0;
573 }
574 
575 static int snd_pcm_substream_proc_init(struct snd_pcm_substream *substream)
576 {
577 	struct snd_info_entry *entry;
578 	struct snd_card *card;
579 	char name[16];
580 
581 	card = substream->pcm->card;
582 
583 	sprintf(name, "sub%i", substream->number);
584 	entry = snd_info_create_card_entry(card, name,
585 					   substream->pstr->proc_root);
586 	if (!entry)
587 		return -ENOMEM;
588 	entry->mode = S_IFDIR | 0555;
589 	if (snd_info_register(entry) < 0) {
590 		snd_info_free_entry(entry);
591 		return -ENOMEM;
592 	}
593 	substream->proc_root = entry;
594 	entry = snd_info_create_card_entry(card, "info", substream->proc_root);
595 	if (entry) {
596 		snd_info_set_text_ops(entry, substream,
597 				      snd_pcm_substream_proc_info_read);
598 		if (snd_info_register(entry) < 0) {
599 			snd_info_free_entry(entry);
600 			entry = NULL;
601 		}
602 	}
603 	substream->proc_info_entry = entry;
604 	entry = snd_info_create_card_entry(card, "hw_params",
605 					   substream->proc_root);
606 	if (entry) {
607 		snd_info_set_text_ops(entry, substream,
608 				      snd_pcm_substream_proc_hw_params_read);
609 		if (snd_info_register(entry) < 0) {
610 			snd_info_free_entry(entry);
611 			entry = NULL;
612 		}
613 	}
614 	substream->proc_hw_params_entry = entry;
615 	entry = snd_info_create_card_entry(card, "sw_params",
616 					   substream->proc_root);
617 	if (entry) {
618 		snd_info_set_text_ops(entry, substream,
619 				      snd_pcm_substream_proc_sw_params_read);
620 		if (snd_info_register(entry) < 0) {
621 			snd_info_free_entry(entry);
622 			entry = NULL;
623 		}
624 	}
625 	substream->proc_sw_params_entry = entry;
626 	entry = snd_info_create_card_entry(card, "status",
627 					   substream->proc_root);
628 	if (entry) {
629 		snd_info_set_text_ops(entry, substream,
630 				      snd_pcm_substream_proc_status_read);
631 		if (snd_info_register(entry) < 0) {
632 			snd_info_free_entry(entry);
633 			entry = NULL;
634 		}
635 	}
636 	substream->proc_status_entry = entry;
637 
638 #ifdef CONFIG_SND_PCM_XRUN_DEBUG
639 	entry = snd_info_create_card_entry(card, "xrun_injection",
640 					   substream->proc_root);
641 	if (entry) {
642 		entry->private_data = substream;
643 		entry->c.text.read = NULL;
644 		entry->c.text.write = snd_pcm_xrun_injection_write;
645 		entry->mode = S_IFREG | 0200;
646 		if (snd_info_register(entry) < 0) {
647 			snd_info_free_entry(entry);
648 			entry = NULL;
649 		}
650 	}
651 	substream->proc_xrun_injection_entry = entry;
652 #endif /* CONFIG_SND_PCM_XRUN_DEBUG */
653 
654 	return 0;
655 }
656 
657 static int snd_pcm_substream_proc_done(struct snd_pcm_substream *substream)
658 {
659 	snd_info_free_entry(substream->proc_info_entry);
660 	substream->proc_info_entry = NULL;
661 	snd_info_free_entry(substream->proc_hw_params_entry);
662 	substream->proc_hw_params_entry = NULL;
663 	snd_info_free_entry(substream->proc_sw_params_entry);
664 	substream->proc_sw_params_entry = NULL;
665 	snd_info_free_entry(substream->proc_status_entry);
666 	substream->proc_status_entry = NULL;
667 #ifdef CONFIG_SND_PCM_XRUN_DEBUG
668 	snd_info_free_entry(substream->proc_xrun_injection_entry);
669 	substream->proc_xrun_injection_entry = NULL;
670 #endif
671 	snd_info_free_entry(substream->proc_root);
672 	substream->proc_root = NULL;
673 	return 0;
674 }
675 #else /* !CONFIG_SND_VERBOSE_PROCFS */
676 static inline int snd_pcm_stream_proc_init(struct snd_pcm_str *pstr) { return 0; }
677 static inline int snd_pcm_stream_proc_done(struct snd_pcm_str *pstr) { return 0; }
678 static inline int snd_pcm_substream_proc_init(struct snd_pcm_substream *substream) { return 0; }
679 static inline int snd_pcm_substream_proc_done(struct snd_pcm_substream *substream) { return 0; }
680 #endif /* CONFIG_SND_VERBOSE_PROCFS */
681 
682 static const struct attribute_group *pcm_dev_attr_groups[];
683 
684 /**
685  * snd_pcm_new_stream - create a new PCM stream
686  * @pcm: the pcm instance
687  * @stream: the stream direction, SNDRV_PCM_STREAM_XXX
688  * @substream_count: the number of substreams
689  *
690  * Creates a new stream for the pcm.
691  * The corresponding stream on the pcm must have been empty before
692  * calling this, i.e. zero must be given to the argument of
693  * snd_pcm_new().
694  *
695  * Return: Zero if successful, or a negative error code on failure.
696  */
697 int snd_pcm_new_stream(struct snd_pcm *pcm, int stream, int substream_count)
698 {
699 	int idx, err;
700 	struct snd_pcm_str *pstr = &pcm->streams[stream];
701 	struct snd_pcm_substream *substream, *prev;
702 
703 #if IS_ENABLED(CONFIG_SND_PCM_OSS)
704 	mutex_init(&pstr->oss.setup_mutex);
705 #endif
706 	pstr->stream = stream;
707 	pstr->pcm = pcm;
708 	pstr->substream_count = substream_count;
709 	if (!substream_count)
710 		return 0;
711 
712 	snd_device_initialize(&pstr->dev, pcm->card);
713 	pstr->dev.groups = pcm_dev_attr_groups;
714 	dev_set_name(&pstr->dev, "pcmC%iD%i%c", pcm->card->number, pcm->device,
715 		     stream == SNDRV_PCM_STREAM_PLAYBACK ? 'p' : 'c');
716 
717 	if (!pcm->internal) {
718 		err = snd_pcm_stream_proc_init(pstr);
719 		if (err < 0) {
720 			pcm_err(pcm, "Error in snd_pcm_stream_proc_init\n");
721 			return err;
722 		}
723 	}
724 	prev = NULL;
725 	for (idx = 0, prev = NULL; idx < substream_count; idx++) {
726 		substream = kzalloc(sizeof(*substream), GFP_KERNEL);
727 		if (!substream)
728 			return -ENOMEM;
729 		substream->pcm = pcm;
730 		substream->pstr = pstr;
731 		substream->number = idx;
732 		substream->stream = stream;
733 		sprintf(substream->name, "subdevice #%i", idx);
734 		substream->buffer_bytes_max = UINT_MAX;
735 		if (prev == NULL)
736 			pstr->substream = substream;
737 		else
738 			prev->next = substream;
739 
740 		if (!pcm->internal) {
741 			err = snd_pcm_substream_proc_init(substream);
742 			if (err < 0) {
743 				pcm_err(pcm,
744 					"Error in snd_pcm_stream_proc_init\n");
745 				if (prev == NULL)
746 					pstr->substream = NULL;
747 				else
748 					prev->next = NULL;
749 				kfree(substream);
750 				return err;
751 			}
752 		}
753 		substream->group = &substream->self_group;
754 		spin_lock_init(&substream->self_group.lock);
755 		mutex_init(&substream->self_group.mutex);
756 		INIT_LIST_HEAD(&substream->self_group.substreams);
757 		list_add_tail(&substream->link_list, &substream->self_group.substreams);
758 		atomic_set(&substream->mmap_count, 0);
759 		prev = substream;
760 	}
761 	return 0;
762 }
763 EXPORT_SYMBOL(snd_pcm_new_stream);
764 
765 static int _snd_pcm_new(struct snd_card *card, const char *id, int device,
766 		int playback_count, int capture_count, bool internal,
767 		struct snd_pcm **rpcm)
768 {
769 	struct snd_pcm *pcm;
770 	int err;
771 	static struct snd_device_ops ops = {
772 		.dev_free = snd_pcm_dev_free,
773 		.dev_register =	snd_pcm_dev_register,
774 		.dev_disconnect = snd_pcm_dev_disconnect,
775 	};
776 	static struct snd_device_ops internal_ops = {
777 		.dev_free = snd_pcm_dev_free,
778 	};
779 
780 	if (snd_BUG_ON(!card))
781 		return -ENXIO;
782 	if (rpcm)
783 		*rpcm = NULL;
784 	pcm = kzalloc(sizeof(*pcm), GFP_KERNEL);
785 	if (!pcm)
786 		return -ENOMEM;
787 	pcm->card = card;
788 	pcm->device = device;
789 	pcm->internal = internal;
790 	mutex_init(&pcm->open_mutex);
791 	init_waitqueue_head(&pcm->open_wait);
792 	INIT_LIST_HEAD(&pcm->list);
793 	if (id)
794 		strlcpy(pcm->id, id, sizeof(pcm->id));
795 
796 	err = snd_pcm_new_stream(pcm, SNDRV_PCM_STREAM_PLAYBACK,
797 				 playback_count);
798 	if (err < 0)
799 		goto free_pcm;
800 
801 	err = snd_pcm_new_stream(pcm, SNDRV_PCM_STREAM_CAPTURE, capture_count);
802 	if (err < 0)
803 		goto free_pcm;
804 
805 	err = snd_device_new(card, SNDRV_DEV_PCM, pcm,
806 			     internal ? &internal_ops : &ops);
807 	if (err < 0)
808 		goto free_pcm;
809 
810 	if (rpcm)
811 		*rpcm = pcm;
812 	return 0;
813 
814 free_pcm:
815 	snd_pcm_free(pcm);
816 	return err;
817 }
818 
819 /**
820  * snd_pcm_new - create a new PCM instance
821  * @card: the card instance
822  * @id: the id string
823  * @device: the device index (zero based)
824  * @playback_count: the number of substreams for playback
825  * @capture_count: the number of substreams for capture
826  * @rpcm: the pointer to store the new pcm instance
827  *
828  * Creates a new PCM instance.
829  *
830  * The pcm operators have to be set afterwards to the new instance
831  * via snd_pcm_set_ops().
832  *
833  * Return: Zero if successful, or a negative error code on failure.
834  */
835 int snd_pcm_new(struct snd_card *card, const char *id, int device,
836 		int playback_count, int capture_count, struct snd_pcm **rpcm)
837 {
838 	return _snd_pcm_new(card, id, device, playback_count, capture_count,
839 			false, rpcm);
840 }
841 EXPORT_SYMBOL(snd_pcm_new);
842 
843 /**
844  * snd_pcm_new_internal - create a new internal PCM instance
845  * @card: the card instance
846  * @id: the id string
847  * @device: the device index (zero based - shared with normal PCMs)
848  * @playback_count: the number of substreams for playback
849  * @capture_count: the number of substreams for capture
850  * @rpcm: the pointer to store the new pcm instance
851  *
852  * Creates a new internal PCM instance with no userspace device or procfs
853  * entries. This is used by ASoC Back End PCMs in order to create a PCM that
854  * will only be used internally by kernel drivers. i.e. it cannot be opened
855  * by userspace. It provides existing ASoC components drivers with a substream
856  * and access to any private data.
857  *
858  * The pcm operators have to be set afterwards to the new instance
859  * via snd_pcm_set_ops().
860  *
861  * Return: Zero if successful, or a negative error code on failure.
862  */
863 int snd_pcm_new_internal(struct snd_card *card, const char *id, int device,
864 	int playback_count, int capture_count,
865 	struct snd_pcm **rpcm)
866 {
867 	return _snd_pcm_new(card, id, device, playback_count, capture_count,
868 			true, rpcm);
869 }
870 EXPORT_SYMBOL(snd_pcm_new_internal);
871 
872 static void free_chmap(struct snd_pcm_str *pstr)
873 {
874 	if (pstr->chmap_kctl) {
875 		snd_ctl_remove(pstr->pcm->card, pstr->chmap_kctl);
876 		pstr->chmap_kctl = NULL;
877 	}
878 }
879 
880 static void snd_pcm_free_stream(struct snd_pcm_str * pstr)
881 {
882 	struct snd_pcm_substream *substream, *substream_next;
883 #if IS_ENABLED(CONFIG_SND_PCM_OSS)
884 	struct snd_pcm_oss_setup *setup, *setupn;
885 #endif
886 	substream = pstr->substream;
887 	while (substream) {
888 		substream_next = substream->next;
889 		snd_pcm_timer_done(substream);
890 		snd_pcm_substream_proc_done(substream);
891 		kfree(substream);
892 		substream = substream_next;
893 	}
894 	snd_pcm_stream_proc_done(pstr);
895 #if IS_ENABLED(CONFIG_SND_PCM_OSS)
896 	for (setup = pstr->oss.setup_list; setup; setup = setupn) {
897 		setupn = setup->next;
898 		kfree(setup->task_name);
899 		kfree(setup);
900 	}
901 #endif
902 	free_chmap(pstr);
903 	if (pstr->substream_count)
904 		put_device(&pstr->dev);
905 }
906 
907 #if IS_ENABLED(CONFIG_SND_PCM_OSS)
908 #define pcm_call_notify(pcm, call)					\
909 	do {								\
910 		struct snd_pcm_notify *_notify;				\
911 		list_for_each_entry(_notify, &snd_pcm_notify_list, list) \
912 			_notify->call(pcm);				\
913 	} while (0)
914 #else
915 #define pcm_call_notify(pcm, call) do {} while (0)
916 #endif
917 
918 static int snd_pcm_free(struct snd_pcm *pcm)
919 {
920 	if (!pcm)
921 		return 0;
922 	if (!pcm->internal)
923 		pcm_call_notify(pcm, n_unregister);
924 	if (pcm->private_free)
925 		pcm->private_free(pcm);
926 	snd_pcm_lib_preallocate_free_for_all(pcm);
927 	snd_pcm_free_stream(&pcm->streams[SNDRV_PCM_STREAM_PLAYBACK]);
928 	snd_pcm_free_stream(&pcm->streams[SNDRV_PCM_STREAM_CAPTURE]);
929 	kfree(pcm);
930 	return 0;
931 }
932 
933 static int snd_pcm_dev_free(struct snd_device *device)
934 {
935 	struct snd_pcm *pcm = device->device_data;
936 	return snd_pcm_free(pcm);
937 }
938 
939 int snd_pcm_attach_substream(struct snd_pcm *pcm, int stream,
940 			     struct file *file,
941 			     struct snd_pcm_substream **rsubstream)
942 {
943 	struct snd_pcm_str * pstr;
944 	struct snd_pcm_substream *substream;
945 	struct snd_pcm_runtime *runtime;
946 	struct snd_card *card;
947 	int prefer_subdevice;
948 	size_t size;
949 
950 	if (snd_BUG_ON(!pcm || !rsubstream))
951 		return -ENXIO;
952 	if (snd_BUG_ON(stream != SNDRV_PCM_STREAM_PLAYBACK &&
953 		       stream != SNDRV_PCM_STREAM_CAPTURE))
954 		return -EINVAL;
955 	*rsubstream = NULL;
956 	pstr = &pcm->streams[stream];
957 	if (pstr->substream == NULL || pstr->substream_count == 0)
958 		return -ENODEV;
959 
960 	card = pcm->card;
961 	prefer_subdevice = snd_ctl_get_preferred_subdevice(card, SND_CTL_SUBDEV_PCM);
962 
963 	if (pcm->info_flags & SNDRV_PCM_INFO_HALF_DUPLEX) {
964 		int opposite = !stream;
965 
966 		for (substream = pcm->streams[opposite].substream; substream;
967 		     substream = substream->next) {
968 			if (SUBSTREAM_BUSY(substream))
969 				return -EAGAIN;
970 		}
971 	}
972 
973 	if (file->f_flags & O_APPEND) {
974 		if (prefer_subdevice < 0) {
975 			if (pstr->substream_count > 1)
976 				return -EINVAL; /* must be unique */
977 			substream = pstr->substream;
978 		} else {
979 			for (substream = pstr->substream; substream;
980 			     substream = substream->next)
981 				if (substream->number == prefer_subdevice)
982 					break;
983 		}
984 		if (! substream)
985 			return -ENODEV;
986 		if (! SUBSTREAM_BUSY(substream))
987 			return -EBADFD;
988 		substream->ref_count++;
989 		*rsubstream = substream;
990 		return 0;
991 	}
992 
993 	for (substream = pstr->substream; substream; substream = substream->next) {
994 		if (!SUBSTREAM_BUSY(substream) &&
995 		    (prefer_subdevice == -1 ||
996 		     substream->number == prefer_subdevice))
997 			break;
998 	}
999 	if (substream == NULL)
1000 		return -EAGAIN;
1001 
1002 	runtime = kzalloc(sizeof(*runtime), GFP_KERNEL);
1003 	if (runtime == NULL)
1004 		return -ENOMEM;
1005 
1006 	size = PAGE_ALIGN(sizeof(struct snd_pcm_mmap_status));
1007 	runtime->status = snd_malloc_pages(size, GFP_KERNEL);
1008 	if (runtime->status == NULL) {
1009 		kfree(runtime);
1010 		return -ENOMEM;
1011 	}
1012 	memset((void*)runtime->status, 0, size);
1013 
1014 	size = PAGE_ALIGN(sizeof(struct snd_pcm_mmap_control));
1015 	runtime->control = snd_malloc_pages(size, GFP_KERNEL);
1016 	if (runtime->control == NULL) {
1017 		snd_free_pages((void*)runtime->status,
1018 			       PAGE_ALIGN(sizeof(struct snd_pcm_mmap_status)));
1019 		kfree(runtime);
1020 		return -ENOMEM;
1021 	}
1022 	memset((void*)runtime->control, 0, size);
1023 
1024 	init_waitqueue_head(&runtime->sleep);
1025 	init_waitqueue_head(&runtime->tsleep);
1026 
1027 	runtime->status->state = SNDRV_PCM_STATE_OPEN;
1028 
1029 	substream->runtime = runtime;
1030 	substream->private_data = pcm->private_data;
1031 	substream->ref_count = 1;
1032 	substream->f_flags = file->f_flags;
1033 	substream->pid = get_pid(task_pid(current));
1034 	pstr->substream_opened++;
1035 	*rsubstream = substream;
1036 	return 0;
1037 }
1038 
1039 void snd_pcm_detach_substream(struct snd_pcm_substream *substream)
1040 {
1041 	struct snd_pcm_runtime *runtime;
1042 
1043 	if (PCM_RUNTIME_CHECK(substream))
1044 		return;
1045 	runtime = substream->runtime;
1046 	if (runtime->private_free != NULL)
1047 		runtime->private_free(runtime);
1048 	snd_free_pages((void*)runtime->status,
1049 		       PAGE_ALIGN(sizeof(struct snd_pcm_mmap_status)));
1050 	snd_free_pages((void*)runtime->control,
1051 		       PAGE_ALIGN(sizeof(struct snd_pcm_mmap_control)));
1052 	kfree(runtime->hw_constraints.rules);
1053 	/* Avoid concurrent access to runtime via PCM timer interface */
1054 	if (substream->timer)
1055 		spin_lock_irq(&substream->timer->lock);
1056 	substream->runtime = NULL;
1057 	if (substream->timer)
1058 		spin_unlock_irq(&substream->timer->lock);
1059 	kfree(runtime);
1060 	put_pid(substream->pid);
1061 	substream->pid = NULL;
1062 	substream->pstr->substream_opened--;
1063 }
1064 
1065 static ssize_t show_pcm_class(struct device *dev,
1066 			      struct device_attribute *attr, char *buf)
1067 {
1068 	struct snd_pcm_str *pstr = container_of(dev, struct snd_pcm_str, dev);
1069 	struct snd_pcm *pcm = pstr->pcm;
1070 	const char *str;
1071 	static const char *strs[SNDRV_PCM_CLASS_LAST + 1] = {
1072 		[SNDRV_PCM_CLASS_GENERIC] = "generic",
1073 		[SNDRV_PCM_CLASS_MULTI] = "multi",
1074 		[SNDRV_PCM_CLASS_MODEM] = "modem",
1075 		[SNDRV_PCM_CLASS_DIGITIZER] = "digitizer",
1076 	};
1077 
1078 	if (pcm->dev_class > SNDRV_PCM_CLASS_LAST)
1079 		str = "none";
1080 	else
1081 		str = strs[pcm->dev_class];
1082         return snprintf(buf, PAGE_SIZE, "%s\n", str);
1083 }
1084 
1085 static DEVICE_ATTR(pcm_class, 0444, show_pcm_class, NULL);
1086 static struct attribute *pcm_dev_attrs[] = {
1087 	&dev_attr_pcm_class.attr,
1088 	NULL
1089 };
1090 
1091 static const struct attribute_group pcm_dev_attr_group = {
1092 	.attrs	= pcm_dev_attrs,
1093 };
1094 
1095 static const struct attribute_group *pcm_dev_attr_groups[] = {
1096 	&pcm_dev_attr_group,
1097 	NULL
1098 };
1099 
1100 static int snd_pcm_dev_register(struct snd_device *device)
1101 {
1102 	int cidx, err;
1103 	struct snd_pcm_substream *substream;
1104 	struct snd_pcm *pcm;
1105 
1106 	if (snd_BUG_ON(!device || !device->device_data))
1107 		return -ENXIO;
1108 	pcm = device->device_data;
1109 
1110 	mutex_lock(&register_mutex);
1111 	err = snd_pcm_add(pcm);
1112 	if (err)
1113 		goto unlock;
1114 	for (cidx = 0; cidx < 2; cidx++) {
1115 		int devtype = -1;
1116 		if (pcm->streams[cidx].substream == NULL)
1117 			continue;
1118 		switch (cidx) {
1119 		case SNDRV_PCM_STREAM_PLAYBACK:
1120 			devtype = SNDRV_DEVICE_TYPE_PCM_PLAYBACK;
1121 			break;
1122 		case SNDRV_PCM_STREAM_CAPTURE:
1123 			devtype = SNDRV_DEVICE_TYPE_PCM_CAPTURE;
1124 			break;
1125 		}
1126 		/* register pcm */
1127 		err = snd_register_device(devtype, pcm->card, pcm->device,
1128 					  &snd_pcm_f_ops[cidx], pcm,
1129 					  &pcm->streams[cidx].dev);
1130 		if (err < 0) {
1131 			list_del_init(&pcm->list);
1132 			goto unlock;
1133 		}
1134 
1135 		for (substream = pcm->streams[cidx].substream; substream; substream = substream->next)
1136 			snd_pcm_timer_init(substream);
1137 	}
1138 
1139 	pcm_call_notify(pcm, n_register);
1140 
1141  unlock:
1142 	mutex_unlock(&register_mutex);
1143 	return err;
1144 }
1145 
1146 static int snd_pcm_dev_disconnect(struct snd_device *device)
1147 {
1148 	struct snd_pcm *pcm = device->device_data;
1149 	struct snd_pcm_substream *substream;
1150 	int cidx;
1151 
1152 	mutex_lock(&register_mutex);
1153 	mutex_lock(&pcm->open_mutex);
1154 	wake_up(&pcm->open_wait);
1155 	list_del_init(&pcm->list);
1156 	for (cidx = 0; cidx < 2; cidx++) {
1157 		for (substream = pcm->streams[cidx].substream; substream; substream = substream->next) {
1158 			snd_pcm_stream_lock_irq(substream);
1159 			if (substream->runtime) {
1160 				if (snd_pcm_running(substream))
1161 					snd_pcm_stop(substream,
1162 						     SNDRV_PCM_STATE_DISCONNECTED);
1163 				/* to be sure, set the state unconditionally */
1164 				substream->runtime->status->state = SNDRV_PCM_STATE_DISCONNECTED;
1165 				wake_up(&substream->runtime->sleep);
1166 				wake_up(&substream->runtime->tsleep);
1167 			}
1168 			snd_pcm_stream_unlock_irq(substream);
1169 		}
1170 	}
1171 
1172 	pcm_call_notify(pcm, n_disconnect);
1173 	for (cidx = 0; cidx < 2; cidx++) {
1174 		snd_unregister_device(&pcm->streams[cidx].dev);
1175 		free_chmap(&pcm->streams[cidx]);
1176 	}
1177 	mutex_unlock(&pcm->open_mutex);
1178 	mutex_unlock(&register_mutex);
1179 	return 0;
1180 }
1181 
1182 #if IS_ENABLED(CONFIG_SND_PCM_OSS)
1183 /**
1184  * snd_pcm_notify - Add/remove the notify list
1185  * @notify: PCM notify list
1186  * @nfree: 0 = register, 1 = unregister
1187  *
1188  * This adds the given notifier to the global list so that the callback is
1189  * called for each registered PCM devices.  This exists only for PCM OSS
1190  * emulation, so far.
1191  */
1192 int snd_pcm_notify(struct snd_pcm_notify *notify, int nfree)
1193 {
1194 	struct snd_pcm *pcm;
1195 
1196 	if (snd_BUG_ON(!notify ||
1197 		       !notify->n_register ||
1198 		       !notify->n_unregister ||
1199 		       !notify->n_disconnect))
1200 		return -EINVAL;
1201 	mutex_lock(&register_mutex);
1202 	if (nfree) {
1203 		list_del(&notify->list);
1204 		list_for_each_entry(pcm, &snd_pcm_devices, list)
1205 			notify->n_unregister(pcm);
1206 	} else {
1207 		list_add_tail(&notify->list, &snd_pcm_notify_list);
1208 		list_for_each_entry(pcm, &snd_pcm_devices, list)
1209 			notify->n_register(pcm);
1210 	}
1211 	mutex_unlock(&register_mutex);
1212 	return 0;
1213 }
1214 EXPORT_SYMBOL(snd_pcm_notify);
1215 #endif /* CONFIG_SND_PCM_OSS */
1216 
1217 #ifdef CONFIG_SND_PROC_FS
1218 /*
1219  *  Info interface
1220  */
1221 
1222 static void snd_pcm_proc_read(struct snd_info_entry *entry,
1223 			      struct snd_info_buffer *buffer)
1224 {
1225 	struct snd_pcm *pcm;
1226 
1227 	mutex_lock(&register_mutex);
1228 	list_for_each_entry(pcm, &snd_pcm_devices, list) {
1229 		snd_iprintf(buffer, "%02i-%02i: %s : %s",
1230 			    pcm->card->number, pcm->device, pcm->id, pcm->name);
1231 		if (pcm->streams[SNDRV_PCM_STREAM_PLAYBACK].substream)
1232 			snd_iprintf(buffer, " : playback %i",
1233 				    pcm->streams[SNDRV_PCM_STREAM_PLAYBACK].substream_count);
1234 		if (pcm->streams[SNDRV_PCM_STREAM_CAPTURE].substream)
1235 			snd_iprintf(buffer, " : capture %i",
1236 				    pcm->streams[SNDRV_PCM_STREAM_CAPTURE].substream_count);
1237 		snd_iprintf(buffer, "\n");
1238 	}
1239 	mutex_unlock(&register_mutex);
1240 }
1241 
1242 static struct snd_info_entry *snd_pcm_proc_entry;
1243 
1244 static void snd_pcm_proc_init(void)
1245 {
1246 	struct snd_info_entry *entry;
1247 
1248 	entry = snd_info_create_module_entry(THIS_MODULE, "pcm", NULL);
1249 	if (entry) {
1250 		snd_info_set_text_ops(entry, NULL, snd_pcm_proc_read);
1251 		if (snd_info_register(entry) < 0) {
1252 			snd_info_free_entry(entry);
1253 			entry = NULL;
1254 		}
1255 	}
1256 	snd_pcm_proc_entry = entry;
1257 }
1258 
1259 static void snd_pcm_proc_done(void)
1260 {
1261 	snd_info_free_entry(snd_pcm_proc_entry);
1262 }
1263 
1264 #else /* !CONFIG_SND_PROC_FS */
1265 #define snd_pcm_proc_init()
1266 #define snd_pcm_proc_done()
1267 #endif /* CONFIG_SND_PROC_FS */
1268 
1269 
1270 /*
1271  *  ENTRY functions
1272  */
1273 
1274 static int __init alsa_pcm_init(void)
1275 {
1276 	snd_ctl_register_ioctl(snd_pcm_control_ioctl);
1277 	snd_ctl_register_ioctl_compat(snd_pcm_control_ioctl);
1278 	snd_pcm_proc_init();
1279 	return 0;
1280 }
1281 
1282 static void __exit alsa_pcm_exit(void)
1283 {
1284 	snd_ctl_unregister_ioctl(snd_pcm_control_ioctl);
1285 	snd_ctl_unregister_ioctl_compat(snd_pcm_control_ioctl);
1286 	snd_pcm_proc_done();
1287 }
1288 
1289 module_init(alsa_pcm_init)
1290 module_exit(alsa_pcm_exit)
1291