xref: /openbmc/linux/sound/drivers/dummy.c (revision f3dfffb3)
1 // SPDX-License-Identifier: GPL-2.0-or-later
2 /*
3  *  Dummy soundcard
4  *  Copyright (c) by Jaroslav Kysela <perex@perex.cz>
5  */
6 
7 #include <linux/init.h>
8 #include <linux/err.h>
9 #include <linux/platform_device.h>
10 #include <linux/jiffies.h>
11 #include <linux/slab.h>
12 #include <linux/time.h>
13 #include <linux/wait.h>
14 #include <linux/hrtimer.h>
15 #include <linux/math64.h>
16 #include <linux/module.h>
17 #include <sound/core.h>
18 #include <sound/control.h>
19 #include <sound/tlv.h>
20 #include <sound/pcm.h>
21 #include <sound/rawmidi.h>
22 #include <sound/info.h>
23 #include <sound/initval.h>
24 
25 MODULE_AUTHOR("Jaroslav Kysela <perex@perex.cz>");
26 MODULE_DESCRIPTION("Dummy soundcard (/dev/null)");
27 MODULE_LICENSE("GPL");
28 
29 #define MAX_PCM_DEVICES		4
30 #define MAX_PCM_SUBSTREAMS	128
31 #define MAX_MIDI_DEVICES	2
32 
33 /* defaults */
34 #define MAX_BUFFER_SIZE		(64*1024)
35 #define MIN_PERIOD_SIZE		64
36 #define MAX_PERIOD_SIZE		MAX_BUFFER_SIZE
37 #define USE_FORMATS 		(SNDRV_PCM_FMTBIT_U8 | SNDRV_PCM_FMTBIT_S16_LE)
38 #define USE_RATE		SNDRV_PCM_RATE_CONTINUOUS | SNDRV_PCM_RATE_8000_48000
39 #define USE_RATE_MIN		5500
40 #define USE_RATE_MAX		48000
41 #define USE_CHANNELS_MIN 	1
42 #define USE_CHANNELS_MAX 	2
43 #define USE_PERIODS_MIN 	1
44 #define USE_PERIODS_MAX 	1024
45 #define USE_MIXER_VOLUME_LEVEL_MIN	-50
46 #define USE_MIXER_VOLUME_LEVEL_MAX	100
47 
48 static int index[SNDRV_CARDS] = SNDRV_DEFAULT_IDX;	/* Index 0-MAX */
49 static char *id[SNDRV_CARDS] = SNDRV_DEFAULT_STR;	/* ID for this card */
50 static bool enable[SNDRV_CARDS] = {1, [1 ... (SNDRV_CARDS - 1)] = 0};
51 static char *model[SNDRV_CARDS] = {[0 ... (SNDRV_CARDS - 1)] = NULL};
52 static int pcm_devs[SNDRV_CARDS] = {[0 ... (SNDRV_CARDS - 1)] = 1};
53 static int pcm_substreams[SNDRV_CARDS] = {[0 ... (SNDRV_CARDS - 1)] = 8};
54 //static int midi_devs[SNDRV_CARDS] = {[0 ... (SNDRV_CARDS - 1)] = 2};
55 static int mixer_volume_level_min = USE_MIXER_VOLUME_LEVEL_MIN;
56 static int mixer_volume_level_max = USE_MIXER_VOLUME_LEVEL_MAX;
57 #ifdef CONFIG_HIGH_RES_TIMERS
58 static bool hrtimer = 1;
59 #endif
60 static bool fake_buffer = 1;
61 
62 module_param_array(index, int, NULL, 0444);
63 MODULE_PARM_DESC(index, "Index value for dummy soundcard.");
64 module_param_array(id, charp, NULL, 0444);
65 MODULE_PARM_DESC(id, "ID string for dummy soundcard.");
66 module_param_array(enable, bool, NULL, 0444);
67 MODULE_PARM_DESC(enable, "Enable this dummy soundcard.");
68 module_param_array(model, charp, NULL, 0444);
69 MODULE_PARM_DESC(model, "Soundcard model.");
70 module_param_array(pcm_devs, int, NULL, 0444);
71 MODULE_PARM_DESC(pcm_devs, "PCM devices # (0-4) for dummy driver.");
72 module_param_array(pcm_substreams, int, NULL, 0444);
73 MODULE_PARM_DESC(pcm_substreams, "PCM substreams # (1-128) for dummy driver.");
74 //module_param_array(midi_devs, int, NULL, 0444);
75 //MODULE_PARM_DESC(midi_devs, "MIDI devices # (0-2) for dummy driver.");
76 module_param(mixer_volume_level_min, int, 0444);
77 MODULE_PARM_DESC(mixer_volume_level_min, "Minimum mixer volume level for dummy driver. Default: -50");
78 module_param(mixer_volume_level_max, int, 0444);
79 MODULE_PARM_DESC(mixer_volume_level_max, "Maximum mixer volume level for dummy driver. Default: 100");
80 module_param(fake_buffer, bool, 0444);
81 MODULE_PARM_DESC(fake_buffer, "Fake buffer allocations.");
82 #ifdef CONFIG_HIGH_RES_TIMERS
83 module_param(hrtimer, bool, 0644);
84 MODULE_PARM_DESC(hrtimer, "Use hrtimer as the timer source.");
85 #endif
86 
87 static struct platform_device *devices[SNDRV_CARDS];
88 
89 #define MIXER_ADDR_MASTER	0
90 #define MIXER_ADDR_LINE		1
91 #define MIXER_ADDR_MIC		2
92 #define MIXER_ADDR_SYNTH	3
93 #define MIXER_ADDR_CD		4
94 #define MIXER_ADDR_LAST		4
95 
96 struct dummy_timer_ops {
97 	int (*create)(struct snd_pcm_substream *);
98 	void (*free)(struct snd_pcm_substream *);
99 	int (*prepare)(struct snd_pcm_substream *);
100 	int (*start)(struct snd_pcm_substream *);
101 	int (*stop)(struct snd_pcm_substream *);
102 	snd_pcm_uframes_t (*pointer)(struct snd_pcm_substream *);
103 };
104 
105 #define get_dummy_ops(substream) \
106 	(*(const struct dummy_timer_ops **)(substream)->runtime->private_data)
107 
108 struct dummy_model {
109 	const char *name;
110 	int (*playback_constraints)(struct snd_pcm_runtime *runtime);
111 	int (*capture_constraints)(struct snd_pcm_runtime *runtime);
112 	u64 formats;
113 	size_t buffer_bytes_max;
114 	size_t period_bytes_min;
115 	size_t period_bytes_max;
116 	unsigned int periods_min;
117 	unsigned int periods_max;
118 	unsigned int rates;
119 	unsigned int rate_min;
120 	unsigned int rate_max;
121 	unsigned int channels_min;
122 	unsigned int channels_max;
123 };
124 
125 struct snd_dummy {
126 	struct snd_card *card;
127 	const struct dummy_model *model;
128 	struct snd_pcm *pcm;
129 	struct snd_pcm_hardware pcm_hw;
130 	spinlock_t mixer_lock;
131 	int mixer_volume[MIXER_ADDR_LAST+1][2];
132 	int capture_source[MIXER_ADDR_LAST+1][2];
133 	int iobox;
134 	struct snd_kcontrol *cd_volume_ctl;
135 	struct snd_kcontrol *cd_switch_ctl;
136 };
137 
138 /*
139  * card models
140  */
141 
142 static int emu10k1_playback_constraints(struct snd_pcm_runtime *runtime)
143 {
144 	int err;
145 	err = snd_pcm_hw_constraint_integer(runtime, SNDRV_PCM_HW_PARAM_PERIODS);
146 	if (err < 0)
147 		return err;
148 	err = snd_pcm_hw_constraint_minmax(runtime, SNDRV_PCM_HW_PARAM_BUFFER_BYTES, 256, UINT_MAX);
149 	if (err < 0)
150 		return err;
151 	return 0;
152 }
153 
154 static const struct dummy_model model_emu10k1 = {
155 	.name = "emu10k1",
156 	.playback_constraints = emu10k1_playback_constraints,
157 	.buffer_bytes_max = 128 * 1024,
158 };
159 
160 static const struct dummy_model model_rme9652 = {
161 	.name = "rme9652",
162 	.buffer_bytes_max = 26 * 64 * 1024,
163 	.formats = SNDRV_PCM_FMTBIT_S32_LE,
164 	.channels_min = 26,
165 	.channels_max = 26,
166 	.periods_min = 2,
167 	.periods_max = 2,
168 };
169 
170 static const struct dummy_model model_ice1712 = {
171 	.name = "ice1712",
172 	.buffer_bytes_max = 256 * 1024,
173 	.formats = SNDRV_PCM_FMTBIT_S32_LE,
174 	.channels_min = 10,
175 	.channels_max = 10,
176 	.periods_min = 1,
177 	.periods_max = 1024,
178 };
179 
180 static const struct dummy_model model_uda1341 = {
181 	.name = "uda1341",
182 	.buffer_bytes_max = 16380,
183 	.formats = SNDRV_PCM_FMTBIT_S16_LE,
184 	.channels_min = 2,
185 	.channels_max = 2,
186 	.periods_min = 2,
187 	.periods_max = 255,
188 };
189 
190 static const struct dummy_model model_ac97 = {
191 	.name = "ac97",
192 	.formats = SNDRV_PCM_FMTBIT_S16_LE,
193 	.channels_min = 2,
194 	.channels_max = 2,
195 	.rates = SNDRV_PCM_RATE_48000,
196 	.rate_min = 48000,
197 	.rate_max = 48000,
198 };
199 
200 static const struct dummy_model model_ca0106 = {
201 	.name = "ca0106",
202 	.formats = SNDRV_PCM_FMTBIT_S16_LE,
203 	.buffer_bytes_max = ((65536-64)*8),
204 	.period_bytes_max = (65536-64),
205 	.periods_min = 2,
206 	.periods_max = 8,
207 	.channels_min = 2,
208 	.channels_max = 2,
209 	.rates = SNDRV_PCM_RATE_48000|SNDRV_PCM_RATE_96000|SNDRV_PCM_RATE_192000,
210 	.rate_min = 48000,
211 	.rate_max = 192000,
212 };
213 
214 static const struct dummy_model *dummy_models[] = {
215 	&model_emu10k1,
216 	&model_rme9652,
217 	&model_ice1712,
218 	&model_uda1341,
219 	&model_ac97,
220 	&model_ca0106,
221 	NULL
222 };
223 
224 /*
225  * system timer interface
226  */
227 
228 struct dummy_systimer_pcm {
229 	/* ops must be the first item */
230 	const struct dummy_timer_ops *timer_ops;
231 	spinlock_t lock;
232 	struct timer_list timer;
233 	unsigned long base_time;
234 	unsigned int frac_pos;	/* fractional sample position (based HZ) */
235 	unsigned int frac_period_rest;
236 	unsigned int frac_buffer_size;	/* buffer_size * HZ */
237 	unsigned int frac_period_size;	/* period_size * HZ */
238 	unsigned int rate;
239 	int elapsed;
240 	struct snd_pcm_substream *substream;
241 };
242 
243 static void dummy_systimer_rearm(struct dummy_systimer_pcm *dpcm)
244 {
245 	mod_timer(&dpcm->timer, jiffies +
246 		DIV_ROUND_UP(dpcm->frac_period_rest, dpcm->rate));
247 }
248 
249 static void dummy_systimer_update(struct dummy_systimer_pcm *dpcm)
250 {
251 	unsigned long delta;
252 
253 	delta = jiffies - dpcm->base_time;
254 	if (!delta)
255 		return;
256 	dpcm->base_time += delta;
257 	delta *= dpcm->rate;
258 	dpcm->frac_pos += delta;
259 	while (dpcm->frac_pos >= dpcm->frac_buffer_size)
260 		dpcm->frac_pos -= dpcm->frac_buffer_size;
261 	while (dpcm->frac_period_rest <= delta) {
262 		dpcm->elapsed++;
263 		dpcm->frac_period_rest += dpcm->frac_period_size;
264 	}
265 	dpcm->frac_period_rest -= delta;
266 }
267 
268 static int dummy_systimer_start(struct snd_pcm_substream *substream)
269 {
270 	struct dummy_systimer_pcm *dpcm = substream->runtime->private_data;
271 	spin_lock(&dpcm->lock);
272 	dpcm->base_time = jiffies;
273 	dummy_systimer_rearm(dpcm);
274 	spin_unlock(&dpcm->lock);
275 	return 0;
276 }
277 
278 static int dummy_systimer_stop(struct snd_pcm_substream *substream)
279 {
280 	struct dummy_systimer_pcm *dpcm = substream->runtime->private_data;
281 	spin_lock(&dpcm->lock);
282 	del_timer(&dpcm->timer);
283 	spin_unlock(&dpcm->lock);
284 	return 0;
285 }
286 
287 static int dummy_systimer_prepare(struct snd_pcm_substream *substream)
288 {
289 	struct snd_pcm_runtime *runtime = substream->runtime;
290 	struct dummy_systimer_pcm *dpcm = runtime->private_data;
291 
292 	dpcm->frac_pos = 0;
293 	dpcm->rate = runtime->rate;
294 	dpcm->frac_buffer_size = runtime->buffer_size * HZ;
295 	dpcm->frac_period_size = runtime->period_size * HZ;
296 	dpcm->frac_period_rest = dpcm->frac_period_size;
297 	dpcm->elapsed = 0;
298 
299 	return 0;
300 }
301 
302 static void dummy_systimer_callback(struct timer_list *t)
303 {
304 	struct dummy_systimer_pcm *dpcm = from_timer(dpcm, t, timer);
305 	unsigned long flags;
306 	int elapsed = 0;
307 
308 	spin_lock_irqsave(&dpcm->lock, flags);
309 	dummy_systimer_update(dpcm);
310 	dummy_systimer_rearm(dpcm);
311 	elapsed = dpcm->elapsed;
312 	dpcm->elapsed = 0;
313 	spin_unlock_irqrestore(&dpcm->lock, flags);
314 	if (elapsed)
315 		snd_pcm_period_elapsed(dpcm->substream);
316 }
317 
318 static snd_pcm_uframes_t
319 dummy_systimer_pointer(struct snd_pcm_substream *substream)
320 {
321 	struct dummy_systimer_pcm *dpcm = substream->runtime->private_data;
322 	snd_pcm_uframes_t pos;
323 
324 	spin_lock(&dpcm->lock);
325 	dummy_systimer_update(dpcm);
326 	pos = dpcm->frac_pos / HZ;
327 	spin_unlock(&dpcm->lock);
328 	return pos;
329 }
330 
331 static int dummy_systimer_create(struct snd_pcm_substream *substream)
332 {
333 	struct dummy_systimer_pcm *dpcm;
334 
335 	dpcm = kzalloc(sizeof(*dpcm), GFP_KERNEL);
336 	if (!dpcm)
337 		return -ENOMEM;
338 	substream->runtime->private_data = dpcm;
339 	timer_setup(&dpcm->timer, dummy_systimer_callback, 0);
340 	spin_lock_init(&dpcm->lock);
341 	dpcm->substream = substream;
342 	return 0;
343 }
344 
345 static void dummy_systimer_free(struct snd_pcm_substream *substream)
346 {
347 	kfree(substream->runtime->private_data);
348 }
349 
350 static const struct dummy_timer_ops dummy_systimer_ops = {
351 	.create =	dummy_systimer_create,
352 	.free =		dummy_systimer_free,
353 	.prepare =	dummy_systimer_prepare,
354 	.start =	dummy_systimer_start,
355 	.stop =		dummy_systimer_stop,
356 	.pointer =	dummy_systimer_pointer,
357 };
358 
359 #ifdef CONFIG_HIGH_RES_TIMERS
360 /*
361  * hrtimer interface
362  */
363 
364 struct dummy_hrtimer_pcm {
365 	/* ops must be the first item */
366 	const struct dummy_timer_ops *timer_ops;
367 	ktime_t base_time;
368 	ktime_t period_time;
369 	atomic_t running;
370 	struct hrtimer timer;
371 	struct snd_pcm_substream *substream;
372 };
373 
374 static enum hrtimer_restart dummy_hrtimer_callback(struct hrtimer *timer)
375 {
376 	struct dummy_hrtimer_pcm *dpcm;
377 
378 	dpcm = container_of(timer, struct dummy_hrtimer_pcm, timer);
379 	if (!atomic_read(&dpcm->running))
380 		return HRTIMER_NORESTART;
381 	/*
382 	 * In cases of XRUN and draining, this calls .trigger to stop PCM
383 	 * substream.
384 	 */
385 	snd_pcm_period_elapsed(dpcm->substream);
386 	if (!atomic_read(&dpcm->running))
387 		return HRTIMER_NORESTART;
388 
389 	hrtimer_forward_now(timer, dpcm->period_time);
390 	return HRTIMER_RESTART;
391 }
392 
393 static int dummy_hrtimer_start(struct snd_pcm_substream *substream)
394 {
395 	struct dummy_hrtimer_pcm *dpcm = substream->runtime->private_data;
396 
397 	dpcm->base_time = hrtimer_cb_get_time(&dpcm->timer);
398 	hrtimer_start(&dpcm->timer, dpcm->period_time, HRTIMER_MODE_REL_SOFT);
399 	atomic_set(&dpcm->running, 1);
400 	return 0;
401 }
402 
403 static int dummy_hrtimer_stop(struct snd_pcm_substream *substream)
404 {
405 	struct dummy_hrtimer_pcm *dpcm = substream->runtime->private_data;
406 
407 	atomic_set(&dpcm->running, 0);
408 	if (!hrtimer_callback_running(&dpcm->timer))
409 		hrtimer_cancel(&dpcm->timer);
410 	return 0;
411 }
412 
413 static inline void dummy_hrtimer_sync(struct dummy_hrtimer_pcm *dpcm)
414 {
415 	hrtimer_cancel(&dpcm->timer);
416 }
417 
418 static snd_pcm_uframes_t
419 dummy_hrtimer_pointer(struct snd_pcm_substream *substream)
420 {
421 	struct snd_pcm_runtime *runtime = substream->runtime;
422 	struct dummy_hrtimer_pcm *dpcm = runtime->private_data;
423 	u64 delta;
424 	u32 pos;
425 
426 	delta = ktime_us_delta(hrtimer_cb_get_time(&dpcm->timer),
427 			       dpcm->base_time);
428 	delta = div_u64(delta * runtime->rate + 999999, 1000000);
429 	div_u64_rem(delta, runtime->buffer_size, &pos);
430 	return pos;
431 }
432 
433 static int dummy_hrtimer_prepare(struct snd_pcm_substream *substream)
434 {
435 	struct snd_pcm_runtime *runtime = substream->runtime;
436 	struct dummy_hrtimer_pcm *dpcm = runtime->private_data;
437 	unsigned int period, rate;
438 	long sec;
439 	unsigned long nsecs;
440 
441 	dummy_hrtimer_sync(dpcm);
442 	period = runtime->period_size;
443 	rate = runtime->rate;
444 	sec = period / rate;
445 	period %= rate;
446 	nsecs = div_u64((u64)period * 1000000000UL + rate - 1, rate);
447 	dpcm->period_time = ktime_set(sec, nsecs);
448 
449 	return 0;
450 }
451 
452 static int dummy_hrtimer_create(struct snd_pcm_substream *substream)
453 {
454 	struct dummy_hrtimer_pcm *dpcm;
455 
456 	dpcm = kzalloc(sizeof(*dpcm), GFP_KERNEL);
457 	if (!dpcm)
458 		return -ENOMEM;
459 	substream->runtime->private_data = dpcm;
460 	hrtimer_init(&dpcm->timer, CLOCK_MONOTONIC, HRTIMER_MODE_REL_SOFT);
461 	dpcm->timer.function = dummy_hrtimer_callback;
462 	dpcm->substream = substream;
463 	atomic_set(&dpcm->running, 0);
464 	return 0;
465 }
466 
467 static void dummy_hrtimer_free(struct snd_pcm_substream *substream)
468 {
469 	struct dummy_hrtimer_pcm *dpcm = substream->runtime->private_data;
470 	dummy_hrtimer_sync(dpcm);
471 	kfree(dpcm);
472 }
473 
474 static const struct dummy_timer_ops dummy_hrtimer_ops = {
475 	.create =	dummy_hrtimer_create,
476 	.free =		dummy_hrtimer_free,
477 	.prepare =	dummy_hrtimer_prepare,
478 	.start =	dummy_hrtimer_start,
479 	.stop =		dummy_hrtimer_stop,
480 	.pointer =	dummy_hrtimer_pointer,
481 };
482 
483 #endif /* CONFIG_HIGH_RES_TIMERS */
484 
485 /*
486  * PCM interface
487  */
488 
489 static int dummy_pcm_trigger(struct snd_pcm_substream *substream, int cmd)
490 {
491 	switch (cmd) {
492 	case SNDRV_PCM_TRIGGER_START:
493 	case SNDRV_PCM_TRIGGER_RESUME:
494 		return get_dummy_ops(substream)->start(substream);
495 	case SNDRV_PCM_TRIGGER_STOP:
496 	case SNDRV_PCM_TRIGGER_SUSPEND:
497 		return get_dummy_ops(substream)->stop(substream);
498 	}
499 	return -EINVAL;
500 }
501 
502 static int dummy_pcm_prepare(struct snd_pcm_substream *substream)
503 {
504 	return get_dummy_ops(substream)->prepare(substream);
505 }
506 
507 static snd_pcm_uframes_t dummy_pcm_pointer(struct snd_pcm_substream *substream)
508 {
509 	return get_dummy_ops(substream)->pointer(substream);
510 }
511 
512 static const struct snd_pcm_hardware dummy_pcm_hardware = {
513 	.info =			(SNDRV_PCM_INFO_MMAP |
514 				 SNDRV_PCM_INFO_INTERLEAVED |
515 				 SNDRV_PCM_INFO_RESUME |
516 				 SNDRV_PCM_INFO_MMAP_VALID),
517 	.formats =		USE_FORMATS,
518 	.rates =		USE_RATE,
519 	.rate_min =		USE_RATE_MIN,
520 	.rate_max =		USE_RATE_MAX,
521 	.channels_min =		USE_CHANNELS_MIN,
522 	.channels_max =		USE_CHANNELS_MAX,
523 	.buffer_bytes_max =	MAX_BUFFER_SIZE,
524 	.period_bytes_min =	MIN_PERIOD_SIZE,
525 	.period_bytes_max =	MAX_PERIOD_SIZE,
526 	.periods_min =		USE_PERIODS_MIN,
527 	.periods_max =		USE_PERIODS_MAX,
528 	.fifo_size =		0,
529 };
530 
531 static int dummy_pcm_hw_params(struct snd_pcm_substream *substream,
532 			       struct snd_pcm_hw_params *hw_params)
533 {
534 	if (fake_buffer) {
535 		/* runtime->dma_bytes has to be set manually to allow mmap */
536 		substream->runtime->dma_bytes = params_buffer_bytes(hw_params);
537 		return 0;
538 	}
539 	return 0;
540 }
541 
542 static int dummy_pcm_open(struct snd_pcm_substream *substream)
543 {
544 	struct snd_dummy *dummy = snd_pcm_substream_chip(substream);
545 	const struct dummy_model *model = dummy->model;
546 	struct snd_pcm_runtime *runtime = substream->runtime;
547 	const struct dummy_timer_ops *ops;
548 	int err;
549 
550 	ops = &dummy_systimer_ops;
551 #ifdef CONFIG_HIGH_RES_TIMERS
552 	if (hrtimer)
553 		ops = &dummy_hrtimer_ops;
554 #endif
555 
556 	err = ops->create(substream);
557 	if (err < 0)
558 		return err;
559 	get_dummy_ops(substream) = ops;
560 
561 	runtime->hw = dummy->pcm_hw;
562 	if (substream->pcm->device & 1) {
563 		runtime->hw.info &= ~SNDRV_PCM_INFO_INTERLEAVED;
564 		runtime->hw.info |= SNDRV_PCM_INFO_NONINTERLEAVED;
565 	}
566 	if (substream->pcm->device & 2)
567 		runtime->hw.info &= ~(SNDRV_PCM_INFO_MMAP |
568 				      SNDRV_PCM_INFO_MMAP_VALID);
569 
570 	if (model == NULL)
571 		return 0;
572 
573 	if (substream->stream == SNDRV_PCM_STREAM_PLAYBACK) {
574 		if (model->playback_constraints)
575 			err = model->playback_constraints(substream->runtime);
576 	} else {
577 		if (model->capture_constraints)
578 			err = model->capture_constraints(substream->runtime);
579 	}
580 	if (err < 0) {
581 		get_dummy_ops(substream)->free(substream);
582 		return err;
583 	}
584 	return 0;
585 }
586 
587 static int dummy_pcm_close(struct snd_pcm_substream *substream)
588 {
589 	get_dummy_ops(substream)->free(substream);
590 	return 0;
591 }
592 
593 /*
594  * dummy buffer handling
595  */
596 
597 static void *dummy_page[2];
598 
599 static void free_fake_buffer(void)
600 {
601 	if (fake_buffer) {
602 		int i;
603 		for (i = 0; i < 2; i++)
604 			if (dummy_page[i]) {
605 				free_page((unsigned long)dummy_page[i]);
606 				dummy_page[i] = NULL;
607 			}
608 	}
609 }
610 
611 static int alloc_fake_buffer(void)
612 {
613 	int i;
614 
615 	if (!fake_buffer)
616 		return 0;
617 	for (i = 0; i < 2; i++) {
618 		dummy_page[i] = (void *)get_zeroed_page(GFP_KERNEL);
619 		if (!dummy_page[i]) {
620 			free_fake_buffer();
621 			return -ENOMEM;
622 		}
623 	}
624 	return 0;
625 }
626 
627 static int dummy_pcm_copy(struct snd_pcm_substream *substream,
628 			  int channel, unsigned long pos,
629 			  struct iov_iter *iter, unsigned long bytes)
630 {
631 	return 0; /* do nothing */
632 }
633 
634 static int dummy_pcm_silence(struct snd_pcm_substream *substream,
635 			     int channel, unsigned long pos,
636 			     unsigned long bytes)
637 {
638 	return 0; /* do nothing */
639 }
640 
641 static struct page *dummy_pcm_page(struct snd_pcm_substream *substream,
642 				   unsigned long offset)
643 {
644 	return virt_to_page(dummy_page[substream->stream]); /* the same page */
645 }
646 
647 static const struct snd_pcm_ops dummy_pcm_ops = {
648 	.open =		dummy_pcm_open,
649 	.close =	dummy_pcm_close,
650 	.hw_params =	dummy_pcm_hw_params,
651 	.prepare =	dummy_pcm_prepare,
652 	.trigger =	dummy_pcm_trigger,
653 	.pointer =	dummy_pcm_pointer,
654 };
655 
656 static const struct snd_pcm_ops dummy_pcm_ops_no_buf = {
657 	.open =		dummy_pcm_open,
658 	.close =	dummy_pcm_close,
659 	.hw_params =	dummy_pcm_hw_params,
660 	.prepare =	dummy_pcm_prepare,
661 	.trigger =	dummy_pcm_trigger,
662 	.pointer =	dummy_pcm_pointer,
663 	.copy =		dummy_pcm_copy,
664 	.fill_silence =	dummy_pcm_silence,
665 	.page =		dummy_pcm_page,
666 };
667 
668 static int snd_card_dummy_pcm(struct snd_dummy *dummy, int device,
669 			      int substreams)
670 {
671 	struct snd_pcm *pcm;
672 	const struct snd_pcm_ops *ops;
673 	int err;
674 
675 	err = snd_pcm_new(dummy->card, "Dummy PCM", device,
676 			       substreams, substreams, &pcm);
677 	if (err < 0)
678 		return err;
679 	dummy->pcm = pcm;
680 	if (fake_buffer)
681 		ops = &dummy_pcm_ops_no_buf;
682 	else
683 		ops = &dummy_pcm_ops;
684 	snd_pcm_set_ops(pcm, SNDRV_PCM_STREAM_PLAYBACK, ops);
685 	snd_pcm_set_ops(pcm, SNDRV_PCM_STREAM_CAPTURE, ops);
686 	pcm->private_data = dummy;
687 	pcm->info_flags = 0;
688 	strcpy(pcm->name, "Dummy PCM");
689 	if (!fake_buffer) {
690 		snd_pcm_set_managed_buffer_all(pcm,
691 			SNDRV_DMA_TYPE_CONTINUOUS,
692 			NULL,
693 			0, 64*1024);
694 	}
695 	return 0;
696 }
697 
698 /*
699  * mixer interface
700  */
701 
702 #define DUMMY_VOLUME(xname, xindex, addr) \
703 { .iface = SNDRV_CTL_ELEM_IFACE_MIXER, \
704   .access = SNDRV_CTL_ELEM_ACCESS_READWRITE | SNDRV_CTL_ELEM_ACCESS_TLV_READ, \
705   .name = xname, .index = xindex, \
706   .info = snd_dummy_volume_info, \
707   .get = snd_dummy_volume_get, .put = snd_dummy_volume_put, \
708   .private_value = addr, \
709   .tlv = { .p = db_scale_dummy } }
710 
711 static int snd_dummy_volume_info(struct snd_kcontrol *kcontrol,
712 				 struct snd_ctl_elem_info *uinfo)
713 {
714 	uinfo->type = SNDRV_CTL_ELEM_TYPE_INTEGER;
715 	uinfo->count = 2;
716 	uinfo->value.integer.min = mixer_volume_level_min;
717 	uinfo->value.integer.max = mixer_volume_level_max;
718 	return 0;
719 }
720 
721 static int snd_dummy_volume_get(struct snd_kcontrol *kcontrol,
722 				struct snd_ctl_elem_value *ucontrol)
723 {
724 	struct snd_dummy *dummy = snd_kcontrol_chip(kcontrol);
725 	int addr = kcontrol->private_value;
726 
727 	spin_lock_irq(&dummy->mixer_lock);
728 	ucontrol->value.integer.value[0] = dummy->mixer_volume[addr][0];
729 	ucontrol->value.integer.value[1] = dummy->mixer_volume[addr][1];
730 	spin_unlock_irq(&dummy->mixer_lock);
731 	return 0;
732 }
733 
734 static int snd_dummy_volume_put(struct snd_kcontrol *kcontrol,
735 				struct snd_ctl_elem_value *ucontrol)
736 {
737 	struct snd_dummy *dummy = snd_kcontrol_chip(kcontrol);
738 	int change, addr = kcontrol->private_value;
739 	int left, right;
740 
741 	left = ucontrol->value.integer.value[0];
742 	if (left < mixer_volume_level_min)
743 		left = mixer_volume_level_min;
744 	if (left > mixer_volume_level_max)
745 		left = mixer_volume_level_max;
746 	right = ucontrol->value.integer.value[1];
747 	if (right < mixer_volume_level_min)
748 		right = mixer_volume_level_min;
749 	if (right > mixer_volume_level_max)
750 		right = mixer_volume_level_max;
751 	spin_lock_irq(&dummy->mixer_lock);
752 	change = dummy->mixer_volume[addr][0] != left ||
753 	         dummy->mixer_volume[addr][1] != right;
754 	dummy->mixer_volume[addr][0] = left;
755 	dummy->mixer_volume[addr][1] = right;
756 	spin_unlock_irq(&dummy->mixer_lock);
757 	return change;
758 }
759 
760 static const DECLARE_TLV_DB_SCALE(db_scale_dummy, -4500, 30, 0);
761 
762 #define DUMMY_CAPSRC(xname, xindex, addr) \
763 { .iface = SNDRV_CTL_ELEM_IFACE_MIXER, .name = xname, .index = xindex, \
764   .info = snd_dummy_capsrc_info, \
765   .get = snd_dummy_capsrc_get, .put = snd_dummy_capsrc_put, \
766   .private_value = addr }
767 
768 #define snd_dummy_capsrc_info	snd_ctl_boolean_stereo_info
769 
770 static int snd_dummy_capsrc_get(struct snd_kcontrol *kcontrol,
771 				struct snd_ctl_elem_value *ucontrol)
772 {
773 	struct snd_dummy *dummy = snd_kcontrol_chip(kcontrol);
774 	int addr = kcontrol->private_value;
775 
776 	spin_lock_irq(&dummy->mixer_lock);
777 	ucontrol->value.integer.value[0] = dummy->capture_source[addr][0];
778 	ucontrol->value.integer.value[1] = dummy->capture_source[addr][1];
779 	spin_unlock_irq(&dummy->mixer_lock);
780 	return 0;
781 }
782 
783 static int snd_dummy_capsrc_put(struct snd_kcontrol *kcontrol, struct snd_ctl_elem_value *ucontrol)
784 {
785 	struct snd_dummy *dummy = snd_kcontrol_chip(kcontrol);
786 	int change, addr = kcontrol->private_value;
787 	int left, right;
788 
789 	left = ucontrol->value.integer.value[0] & 1;
790 	right = ucontrol->value.integer.value[1] & 1;
791 	spin_lock_irq(&dummy->mixer_lock);
792 	change = dummy->capture_source[addr][0] != left &&
793 	         dummy->capture_source[addr][1] != right;
794 	dummy->capture_source[addr][0] = left;
795 	dummy->capture_source[addr][1] = right;
796 	spin_unlock_irq(&dummy->mixer_lock);
797 	return change;
798 }
799 
800 static int snd_dummy_iobox_info(struct snd_kcontrol *kcontrol,
801 				struct snd_ctl_elem_info *info)
802 {
803 	static const char *const names[] = { "None", "CD Player" };
804 
805 	return snd_ctl_enum_info(info, 1, 2, names);
806 }
807 
808 static int snd_dummy_iobox_get(struct snd_kcontrol *kcontrol,
809 			       struct snd_ctl_elem_value *value)
810 {
811 	struct snd_dummy *dummy = snd_kcontrol_chip(kcontrol);
812 
813 	value->value.enumerated.item[0] = dummy->iobox;
814 	return 0;
815 }
816 
817 static int snd_dummy_iobox_put(struct snd_kcontrol *kcontrol,
818 			       struct snd_ctl_elem_value *value)
819 {
820 	struct snd_dummy *dummy = snd_kcontrol_chip(kcontrol);
821 	int changed;
822 
823 	if (value->value.enumerated.item[0] > 1)
824 		return -EINVAL;
825 
826 	changed = value->value.enumerated.item[0] != dummy->iobox;
827 	if (changed) {
828 		dummy->iobox = value->value.enumerated.item[0];
829 
830 		if (dummy->iobox) {
831 			dummy->cd_volume_ctl->vd[0].access &=
832 				~SNDRV_CTL_ELEM_ACCESS_INACTIVE;
833 			dummy->cd_switch_ctl->vd[0].access &=
834 				~SNDRV_CTL_ELEM_ACCESS_INACTIVE;
835 		} else {
836 			dummy->cd_volume_ctl->vd[0].access |=
837 				SNDRV_CTL_ELEM_ACCESS_INACTIVE;
838 			dummy->cd_switch_ctl->vd[0].access |=
839 				SNDRV_CTL_ELEM_ACCESS_INACTIVE;
840 		}
841 
842 		snd_ctl_notify(dummy->card, SNDRV_CTL_EVENT_MASK_INFO,
843 			       &dummy->cd_volume_ctl->id);
844 		snd_ctl_notify(dummy->card, SNDRV_CTL_EVENT_MASK_INFO,
845 			       &dummy->cd_switch_ctl->id);
846 	}
847 
848 	return changed;
849 }
850 
851 static const struct snd_kcontrol_new snd_dummy_controls[] = {
852 DUMMY_VOLUME("Master Volume", 0, MIXER_ADDR_MASTER),
853 DUMMY_CAPSRC("Master Capture Switch", 0, MIXER_ADDR_MASTER),
854 DUMMY_VOLUME("Synth Volume", 0, MIXER_ADDR_SYNTH),
855 DUMMY_CAPSRC("Synth Capture Switch", 0, MIXER_ADDR_SYNTH),
856 DUMMY_VOLUME("Line Volume", 0, MIXER_ADDR_LINE),
857 DUMMY_CAPSRC("Line Capture Switch", 0, MIXER_ADDR_LINE),
858 DUMMY_VOLUME("Mic Volume", 0, MIXER_ADDR_MIC),
859 DUMMY_CAPSRC("Mic Capture Switch", 0, MIXER_ADDR_MIC),
860 DUMMY_VOLUME("CD Volume", 0, MIXER_ADDR_CD),
861 DUMMY_CAPSRC("CD Capture Switch", 0, MIXER_ADDR_CD),
862 {
863 	.iface = SNDRV_CTL_ELEM_IFACE_MIXER,
864 	.name  = "External I/O Box",
865 	.info  = snd_dummy_iobox_info,
866 	.get   = snd_dummy_iobox_get,
867 	.put   = snd_dummy_iobox_put,
868 },
869 };
870 
871 static int snd_card_dummy_new_mixer(struct snd_dummy *dummy)
872 {
873 	struct snd_card *card = dummy->card;
874 	struct snd_kcontrol *kcontrol;
875 	unsigned int idx;
876 	int err;
877 
878 	spin_lock_init(&dummy->mixer_lock);
879 	strcpy(card->mixername, "Dummy Mixer");
880 	dummy->iobox = 1;
881 
882 	for (idx = 0; idx < ARRAY_SIZE(snd_dummy_controls); idx++) {
883 		kcontrol = snd_ctl_new1(&snd_dummy_controls[idx], dummy);
884 		err = snd_ctl_add(card, kcontrol);
885 		if (err < 0)
886 			return err;
887 		if (!strcmp(kcontrol->id.name, "CD Volume"))
888 			dummy->cd_volume_ctl = kcontrol;
889 		else if (!strcmp(kcontrol->id.name, "CD Capture Switch"))
890 			dummy->cd_switch_ctl = kcontrol;
891 
892 	}
893 	return 0;
894 }
895 
896 #if defined(CONFIG_SND_DEBUG) && defined(CONFIG_SND_PROC_FS)
897 /*
898  * proc interface
899  */
900 static void print_formats(struct snd_dummy *dummy,
901 			  struct snd_info_buffer *buffer)
902 {
903 	snd_pcm_format_t i;
904 
905 	pcm_for_each_format(i) {
906 		if (dummy->pcm_hw.formats & pcm_format_to_bits(i))
907 			snd_iprintf(buffer, " %s", snd_pcm_format_name(i));
908 	}
909 }
910 
911 static void print_rates(struct snd_dummy *dummy,
912 			struct snd_info_buffer *buffer)
913 {
914 	static const int rates[] = {
915 		5512, 8000, 11025, 16000, 22050, 32000, 44100, 48000,
916 		64000, 88200, 96000, 176400, 192000,
917 	};
918 	int i;
919 
920 	if (dummy->pcm_hw.rates & SNDRV_PCM_RATE_CONTINUOUS)
921 		snd_iprintf(buffer, " continuous");
922 	if (dummy->pcm_hw.rates & SNDRV_PCM_RATE_KNOT)
923 		snd_iprintf(buffer, " knot");
924 	for (i = 0; i < ARRAY_SIZE(rates); i++)
925 		if (dummy->pcm_hw.rates & (1 << i))
926 			snd_iprintf(buffer, " %d", rates[i]);
927 }
928 
929 #define get_dummy_int_ptr(dummy, ofs) \
930 	(unsigned int *)((char *)&((dummy)->pcm_hw) + (ofs))
931 #define get_dummy_ll_ptr(dummy, ofs) \
932 	(unsigned long long *)((char *)&((dummy)->pcm_hw) + (ofs))
933 
934 struct dummy_hw_field {
935 	const char *name;
936 	const char *format;
937 	unsigned int offset;
938 	unsigned int size;
939 };
940 #define FIELD_ENTRY(item, fmt) {		   \
941 	.name = #item,				   \
942 	.format = fmt,				   \
943 	.offset = offsetof(struct snd_pcm_hardware, item), \
944 	.size = sizeof(dummy_pcm_hardware.item) }
945 
946 static const struct dummy_hw_field fields[] = {
947 	FIELD_ENTRY(formats, "%#llx"),
948 	FIELD_ENTRY(rates, "%#x"),
949 	FIELD_ENTRY(rate_min, "%d"),
950 	FIELD_ENTRY(rate_max, "%d"),
951 	FIELD_ENTRY(channels_min, "%d"),
952 	FIELD_ENTRY(channels_max, "%d"),
953 	FIELD_ENTRY(buffer_bytes_max, "%ld"),
954 	FIELD_ENTRY(period_bytes_min, "%ld"),
955 	FIELD_ENTRY(period_bytes_max, "%ld"),
956 	FIELD_ENTRY(periods_min, "%d"),
957 	FIELD_ENTRY(periods_max, "%d"),
958 };
959 
960 static void dummy_proc_read(struct snd_info_entry *entry,
961 			    struct snd_info_buffer *buffer)
962 {
963 	struct snd_dummy *dummy = entry->private_data;
964 	int i;
965 
966 	for (i = 0; i < ARRAY_SIZE(fields); i++) {
967 		snd_iprintf(buffer, "%s ", fields[i].name);
968 		if (fields[i].size == sizeof(int))
969 			snd_iprintf(buffer, fields[i].format,
970 				*get_dummy_int_ptr(dummy, fields[i].offset));
971 		else
972 			snd_iprintf(buffer, fields[i].format,
973 				*get_dummy_ll_ptr(dummy, fields[i].offset));
974 		if (!strcmp(fields[i].name, "formats"))
975 			print_formats(dummy, buffer);
976 		else if (!strcmp(fields[i].name, "rates"))
977 			print_rates(dummy, buffer);
978 		snd_iprintf(buffer, "\n");
979 	}
980 }
981 
982 static void dummy_proc_write(struct snd_info_entry *entry,
983 			     struct snd_info_buffer *buffer)
984 {
985 	struct snd_dummy *dummy = entry->private_data;
986 	char line[64];
987 
988 	while (!snd_info_get_line(buffer, line, sizeof(line))) {
989 		char item[20];
990 		const char *ptr;
991 		unsigned long long val;
992 		int i;
993 
994 		ptr = snd_info_get_str(item, line, sizeof(item));
995 		for (i = 0; i < ARRAY_SIZE(fields); i++) {
996 			if (!strcmp(item, fields[i].name))
997 				break;
998 		}
999 		if (i >= ARRAY_SIZE(fields))
1000 			continue;
1001 		snd_info_get_str(item, ptr, sizeof(item));
1002 		if (kstrtoull(item, 0, &val))
1003 			continue;
1004 		if (fields[i].size == sizeof(int))
1005 			*get_dummy_int_ptr(dummy, fields[i].offset) = val;
1006 		else
1007 			*get_dummy_ll_ptr(dummy, fields[i].offset) = val;
1008 	}
1009 }
1010 
1011 static void dummy_proc_init(struct snd_dummy *chip)
1012 {
1013 	snd_card_rw_proc_new(chip->card, "dummy_pcm", chip,
1014 			     dummy_proc_read, dummy_proc_write);
1015 }
1016 #else
1017 #define dummy_proc_init(x)
1018 #endif /* CONFIG_SND_DEBUG && CONFIG_SND_PROC_FS */
1019 
1020 static int snd_dummy_probe(struct platform_device *devptr)
1021 {
1022 	struct snd_card *card;
1023 	struct snd_dummy *dummy;
1024 	const struct dummy_model *m = NULL, **mdl;
1025 	int idx, err;
1026 	int dev = devptr->id;
1027 
1028 	err = snd_devm_card_new(&devptr->dev, index[dev], id[dev], THIS_MODULE,
1029 				sizeof(struct snd_dummy), &card);
1030 	if (err < 0)
1031 		return err;
1032 	dummy = card->private_data;
1033 	dummy->card = card;
1034 	for (mdl = dummy_models; *mdl && model[dev]; mdl++) {
1035 		if (strcmp(model[dev], (*mdl)->name) == 0) {
1036 			printk(KERN_INFO
1037 				"snd-dummy: Using model '%s' for card %i\n",
1038 				(*mdl)->name, card->number);
1039 			m = dummy->model = *mdl;
1040 			break;
1041 		}
1042 	}
1043 	for (idx = 0; idx < MAX_PCM_DEVICES && idx < pcm_devs[dev]; idx++) {
1044 		if (pcm_substreams[dev] < 1)
1045 			pcm_substreams[dev] = 1;
1046 		if (pcm_substreams[dev] > MAX_PCM_SUBSTREAMS)
1047 			pcm_substreams[dev] = MAX_PCM_SUBSTREAMS;
1048 		err = snd_card_dummy_pcm(dummy, idx, pcm_substreams[dev]);
1049 		if (err < 0)
1050 			return err;
1051 	}
1052 
1053 	dummy->pcm_hw = dummy_pcm_hardware;
1054 	if (m) {
1055 		if (m->formats)
1056 			dummy->pcm_hw.formats = m->formats;
1057 		if (m->buffer_bytes_max)
1058 			dummy->pcm_hw.buffer_bytes_max = m->buffer_bytes_max;
1059 		if (m->period_bytes_min)
1060 			dummy->pcm_hw.period_bytes_min = m->period_bytes_min;
1061 		if (m->period_bytes_max)
1062 			dummy->pcm_hw.period_bytes_max = m->period_bytes_max;
1063 		if (m->periods_min)
1064 			dummy->pcm_hw.periods_min = m->periods_min;
1065 		if (m->periods_max)
1066 			dummy->pcm_hw.periods_max = m->periods_max;
1067 		if (m->rates)
1068 			dummy->pcm_hw.rates = m->rates;
1069 		if (m->rate_min)
1070 			dummy->pcm_hw.rate_min = m->rate_min;
1071 		if (m->rate_max)
1072 			dummy->pcm_hw.rate_max = m->rate_max;
1073 		if (m->channels_min)
1074 			dummy->pcm_hw.channels_min = m->channels_min;
1075 		if (m->channels_max)
1076 			dummy->pcm_hw.channels_max = m->channels_max;
1077 	}
1078 
1079 	if (mixer_volume_level_min > mixer_volume_level_max) {
1080 		pr_warn("snd-dummy: Invalid mixer volume level: min=%d, max=%d. Fall back to default value.\n",
1081 		mixer_volume_level_min, mixer_volume_level_max);
1082 		mixer_volume_level_min = USE_MIXER_VOLUME_LEVEL_MIN;
1083 		mixer_volume_level_max = USE_MIXER_VOLUME_LEVEL_MAX;
1084 	}
1085 	err = snd_card_dummy_new_mixer(dummy);
1086 	if (err < 0)
1087 		return err;
1088 	strcpy(card->driver, "Dummy");
1089 	strcpy(card->shortname, "Dummy");
1090 	sprintf(card->longname, "Dummy %i", dev + 1);
1091 
1092 	dummy_proc_init(dummy);
1093 
1094 	err = snd_card_register(card);
1095 	if (err < 0)
1096 		return err;
1097 	platform_set_drvdata(devptr, card);
1098 	return 0;
1099 }
1100 
1101 #ifdef CONFIG_PM_SLEEP
1102 static int snd_dummy_suspend(struct device *pdev)
1103 {
1104 	struct snd_card *card = dev_get_drvdata(pdev);
1105 
1106 	snd_power_change_state(card, SNDRV_CTL_POWER_D3hot);
1107 	return 0;
1108 }
1109 
1110 static int snd_dummy_resume(struct device *pdev)
1111 {
1112 	struct snd_card *card = dev_get_drvdata(pdev);
1113 
1114 	snd_power_change_state(card, SNDRV_CTL_POWER_D0);
1115 	return 0;
1116 }
1117 
1118 static SIMPLE_DEV_PM_OPS(snd_dummy_pm, snd_dummy_suspend, snd_dummy_resume);
1119 #define SND_DUMMY_PM_OPS	&snd_dummy_pm
1120 #else
1121 #define SND_DUMMY_PM_OPS	NULL
1122 #endif
1123 
1124 #define SND_DUMMY_DRIVER	"snd_dummy"
1125 
1126 static struct platform_driver snd_dummy_driver = {
1127 	.probe		= snd_dummy_probe,
1128 	.driver		= {
1129 		.name	= SND_DUMMY_DRIVER,
1130 		.pm	= SND_DUMMY_PM_OPS,
1131 	},
1132 };
1133 
1134 static void snd_dummy_unregister_all(void)
1135 {
1136 	int i;
1137 
1138 	for (i = 0; i < ARRAY_SIZE(devices); ++i)
1139 		platform_device_unregister(devices[i]);
1140 	platform_driver_unregister(&snd_dummy_driver);
1141 	free_fake_buffer();
1142 }
1143 
1144 static int __init alsa_card_dummy_init(void)
1145 {
1146 	int i, cards, err;
1147 
1148 	err = platform_driver_register(&snd_dummy_driver);
1149 	if (err < 0)
1150 		return err;
1151 
1152 	err = alloc_fake_buffer();
1153 	if (err < 0) {
1154 		platform_driver_unregister(&snd_dummy_driver);
1155 		return err;
1156 	}
1157 
1158 	cards = 0;
1159 	for (i = 0; i < SNDRV_CARDS; i++) {
1160 		struct platform_device *device;
1161 		if (! enable[i])
1162 			continue;
1163 		device = platform_device_register_simple(SND_DUMMY_DRIVER,
1164 							 i, NULL, 0);
1165 		if (IS_ERR(device))
1166 			continue;
1167 		if (!platform_get_drvdata(device)) {
1168 			platform_device_unregister(device);
1169 			continue;
1170 		}
1171 		devices[i] = device;
1172 		cards++;
1173 	}
1174 	if (!cards) {
1175 #ifdef MODULE
1176 		printk(KERN_ERR "Dummy soundcard not found or device busy\n");
1177 #endif
1178 		snd_dummy_unregister_all();
1179 		return -ENODEV;
1180 	}
1181 	return 0;
1182 }
1183 
1184 static void __exit alsa_card_dummy_exit(void)
1185 {
1186 	snd_dummy_unregister_all();
1187 }
1188 
1189 module_init(alsa_card_dummy_init)
1190 module_exit(alsa_card_dummy_exit)
1191