xref: /openbmc/linux/sound/drivers/dummy.c (revision 2359ccdd)
1 /*
2  *  Dummy soundcard
3  *  Copyright (c) by Jaroslav Kysela <perex@perex.cz>
4  *
5  *   This program is free software; you can redistribute it and/or modify
6  *   it under the terms of the GNU General Public License as published by
7  *   the Free Software Foundation; either version 2 of the License, or
8  *   (at your option) any later version.
9  *
10  *   This program is distributed in the hope that it will be useful,
11  *   but WITHOUT ANY WARRANTY; without even the implied warranty of
12  *   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
13  *   GNU General Public License for more details.
14  *
15  *   You should have received a copy of the GNU General Public License
16  *   along with this program; if not, write to the Free Software
17  *   Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307 USA
18  *
19  */
20 
21 #include <linux/init.h>
22 #include <linux/err.h>
23 #include <linux/platform_device.h>
24 #include <linux/jiffies.h>
25 #include <linux/slab.h>
26 #include <linux/time.h>
27 #include <linux/wait.h>
28 #include <linux/hrtimer.h>
29 #include <linux/math64.h>
30 #include <linux/module.h>
31 #include <sound/core.h>
32 #include <sound/control.h>
33 #include <sound/tlv.h>
34 #include <sound/pcm.h>
35 #include <sound/rawmidi.h>
36 #include <sound/info.h>
37 #include <sound/initval.h>
38 
39 MODULE_AUTHOR("Jaroslav Kysela <perex@perex.cz>");
40 MODULE_DESCRIPTION("Dummy soundcard (/dev/null)");
41 MODULE_LICENSE("GPL");
42 MODULE_SUPPORTED_DEVICE("{{ALSA,Dummy soundcard}}");
43 
44 #define MAX_PCM_DEVICES		4
45 #define MAX_PCM_SUBSTREAMS	128
46 #define MAX_MIDI_DEVICES	2
47 
48 /* defaults */
49 #define MAX_BUFFER_SIZE		(64*1024)
50 #define MIN_PERIOD_SIZE		64
51 #define MAX_PERIOD_SIZE		MAX_BUFFER_SIZE
52 #define USE_FORMATS 		(SNDRV_PCM_FMTBIT_U8 | SNDRV_PCM_FMTBIT_S16_LE)
53 #define USE_RATE		SNDRV_PCM_RATE_CONTINUOUS | SNDRV_PCM_RATE_8000_48000
54 #define USE_RATE_MIN		5500
55 #define USE_RATE_MAX		48000
56 #define USE_CHANNELS_MIN 	1
57 #define USE_CHANNELS_MAX 	2
58 #define USE_PERIODS_MIN 	1
59 #define USE_PERIODS_MAX 	1024
60 
61 static int index[SNDRV_CARDS] = SNDRV_DEFAULT_IDX;	/* Index 0-MAX */
62 static char *id[SNDRV_CARDS] = SNDRV_DEFAULT_STR;	/* ID for this card */
63 static bool enable[SNDRV_CARDS] = {1, [1 ... (SNDRV_CARDS - 1)] = 0};
64 static char *model[SNDRV_CARDS] = {[0 ... (SNDRV_CARDS - 1)] = NULL};
65 static int pcm_devs[SNDRV_CARDS] = {[0 ... (SNDRV_CARDS - 1)] = 1};
66 static int pcm_substreams[SNDRV_CARDS] = {[0 ... (SNDRV_CARDS - 1)] = 8};
67 //static int midi_devs[SNDRV_CARDS] = {[0 ... (SNDRV_CARDS - 1)] = 2};
68 #ifdef CONFIG_HIGH_RES_TIMERS
69 static bool hrtimer = 1;
70 #endif
71 static bool fake_buffer = 1;
72 
73 module_param_array(index, int, NULL, 0444);
74 MODULE_PARM_DESC(index, "Index value for dummy soundcard.");
75 module_param_array(id, charp, NULL, 0444);
76 MODULE_PARM_DESC(id, "ID string for dummy soundcard.");
77 module_param_array(enable, bool, NULL, 0444);
78 MODULE_PARM_DESC(enable, "Enable this dummy soundcard.");
79 module_param_array(model, charp, NULL, 0444);
80 MODULE_PARM_DESC(model, "Soundcard model.");
81 module_param_array(pcm_devs, int, NULL, 0444);
82 MODULE_PARM_DESC(pcm_devs, "PCM devices # (0-4) for dummy driver.");
83 module_param_array(pcm_substreams, int, NULL, 0444);
84 MODULE_PARM_DESC(pcm_substreams, "PCM substreams # (1-128) for dummy driver.");
85 //module_param_array(midi_devs, int, NULL, 0444);
86 //MODULE_PARM_DESC(midi_devs, "MIDI devices # (0-2) for dummy driver.");
87 module_param(fake_buffer, bool, 0444);
88 MODULE_PARM_DESC(fake_buffer, "Fake buffer allocations.");
89 #ifdef CONFIG_HIGH_RES_TIMERS
90 module_param(hrtimer, bool, 0644);
91 MODULE_PARM_DESC(hrtimer, "Use hrtimer as the timer source.");
92 #endif
93 
94 static struct platform_device *devices[SNDRV_CARDS];
95 
96 #define MIXER_ADDR_MASTER	0
97 #define MIXER_ADDR_LINE		1
98 #define MIXER_ADDR_MIC		2
99 #define MIXER_ADDR_SYNTH	3
100 #define MIXER_ADDR_CD		4
101 #define MIXER_ADDR_LAST		4
102 
103 struct dummy_timer_ops {
104 	int (*create)(struct snd_pcm_substream *);
105 	void (*free)(struct snd_pcm_substream *);
106 	int (*prepare)(struct snd_pcm_substream *);
107 	int (*start)(struct snd_pcm_substream *);
108 	int (*stop)(struct snd_pcm_substream *);
109 	snd_pcm_uframes_t (*pointer)(struct snd_pcm_substream *);
110 };
111 
112 #define get_dummy_ops(substream) \
113 	(*(const struct dummy_timer_ops **)(substream)->runtime->private_data)
114 
115 struct dummy_model {
116 	const char *name;
117 	int (*playback_constraints)(struct snd_pcm_runtime *runtime);
118 	int (*capture_constraints)(struct snd_pcm_runtime *runtime);
119 	u64 formats;
120 	size_t buffer_bytes_max;
121 	size_t period_bytes_min;
122 	size_t period_bytes_max;
123 	unsigned int periods_min;
124 	unsigned int periods_max;
125 	unsigned int rates;
126 	unsigned int rate_min;
127 	unsigned int rate_max;
128 	unsigned int channels_min;
129 	unsigned int channels_max;
130 };
131 
132 struct snd_dummy {
133 	struct snd_card *card;
134 	struct dummy_model *model;
135 	struct snd_pcm *pcm;
136 	struct snd_pcm_hardware pcm_hw;
137 	spinlock_t mixer_lock;
138 	int mixer_volume[MIXER_ADDR_LAST+1][2];
139 	int capture_source[MIXER_ADDR_LAST+1][2];
140 	int iobox;
141 	struct snd_kcontrol *cd_volume_ctl;
142 	struct snd_kcontrol *cd_switch_ctl;
143 };
144 
145 /*
146  * card models
147  */
148 
149 static int emu10k1_playback_constraints(struct snd_pcm_runtime *runtime)
150 {
151 	int err;
152 	err = snd_pcm_hw_constraint_integer(runtime, SNDRV_PCM_HW_PARAM_PERIODS);
153 	if (err < 0)
154 		return err;
155 	err = snd_pcm_hw_constraint_minmax(runtime, SNDRV_PCM_HW_PARAM_BUFFER_BYTES, 256, UINT_MAX);
156 	if (err < 0)
157 		return err;
158 	return 0;
159 }
160 
161 static struct dummy_model model_emu10k1 = {
162 	.name = "emu10k1",
163 	.playback_constraints = emu10k1_playback_constraints,
164 	.buffer_bytes_max = 128 * 1024,
165 };
166 
167 static struct dummy_model model_rme9652 = {
168 	.name = "rme9652",
169 	.buffer_bytes_max = 26 * 64 * 1024,
170 	.formats = SNDRV_PCM_FMTBIT_S32_LE,
171 	.channels_min = 26,
172 	.channels_max = 26,
173 	.periods_min = 2,
174 	.periods_max = 2,
175 };
176 
177 static struct dummy_model model_ice1712 = {
178 	.name = "ice1712",
179 	.buffer_bytes_max = 256 * 1024,
180 	.formats = SNDRV_PCM_FMTBIT_S32_LE,
181 	.channels_min = 10,
182 	.channels_max = 10,
183 	.periods_min = 1,
184 	.periods_max = 1024,
185 };
186 
187 static struct dummy_model model_uda1341 = {
188 	.name = "uda1341",
189 	.buffer_bytes_max = 16380,
190 	.formats = SNDRV_PCM_FMTBIT_S16_LE,
191 	.channels_min = 2,
192 	.channels_max = 2,
193 	.periods_min = 2,
194 	.periods_max = 255,
195 };
196 
197 static struct dummy_model model_ac97 = {
198 	.name = "ac97",
199 	.formats = SNDRV_PCM_FMTBIT_S16_LE,
200 	.channels_min = 2,
201 	.channels_max = 2,
202 	.rates = SNDRV_PCM_RATE_48000,
203 	.rate_min = 48000,
204 	.rate_max = 48000,
205 };
206 
207 static struct dummy_model model_ca0106 = {
208 	.name = "ca0106",
209 	.formats = SNDRV_PCM_FMTBIT_S16_LE,
210 	.buffer_bytes_max = ((65536-64)*8),
211 	.period_bytes_max = (65536-64),
212 	.periods_min = 2,
213 	.periods_max = 8,
214 	.channels_min = 2,
215 	.channels_max = 2,
216 	.rates = SNDRV_PCM_RATE_48000|SNDRV_PCM_RATE_96000|SNDRV_PCM_RATE_192000,
217 	.rate_min = 48000,
218 	.rate_max = 192000,
219 };
220 
221 static struct dummy_model *dummy_models[] = {
222 	&model_emu10k1,
223 	&model_rme9652,
224 	&model_ice1712,
225 	&model_uda1341,
226 	&model_ac97,
227 	&model_ca0106,
228 	NULL
229 };
230 
231 /*
232  * system timer interface
233  */
234 
235 struct dummy_systimer_pcm {
236 	/* ops must be the first item */
237 	const struct dummy_timer_ops *timer_ops;
238 	spinlock_t lock;
239 	struct timer_list timer;
240 	unsigned long base_time;
241 	unsigned int frac_pos;	/* fractional sample position (based HZ) */
242 	unsigned int frac_period_rest;
243 	unsigned int frac_buffer_size;	/* buffer_size * HZ */
244 	unsigned int frac_period_size;	/* period_size * HZ */
245 	unsigned int rate;
246 	int elapsed;
247 	struct snd_pcm_substream *substream;
248 };
249 
250 static void dummy_systimer_rearm(struct dummy_systimer_pcm *dpcm)
251 {
252 	mod_timer(&dpcm->timer, jiffies +
253 		(dpcm->frac_period_rest + dpcm->rate - 1) / dpcm->rate);
254 }
255 
256 static void dummy_systimer_update(struct dummy_systimer_pcm *dpcm)
257 {
258 	unsigned long delta;
259 
260 	delta = jiffies - dpcm->base_time;
261 	if (!delta)
262 		return;
263 	dpcm->base_time += delta;
264 	delta *= dpcm->rate;
265 	dpcm->frac_pos += delta;
266 	while (dpcm->frac_pos >= dpcm->frac_buffer_size)
267 		dpcm->frac_pos -= dpcm->frac_buffer_size;
268 	while (dpcm->frac_period_rest <= delta) {
269 		dpcm->elapsed++;
270 		dpcm->frac_period_rest += dpcm->frac_period_size;
271 	}
272 	dpcm->frac_period_rest -= delta;
273 }
274 
275 static int dummy_systimer_start(struct snd_pcm_substream *substream)
276 {
277 	struct dummy_systimer_pcm *dpcm = substream->runtime->private_data;
278 	spin_lock(&dpcm->lock);
279 	dpcm->base_time = jiffies;
280 	dummy_systimer_rearm(dpcm);
281 	spin_unlock(&dpcm->lock);
282 	return 0;
283 }
284 
285 static int dummy_systimer_stop(struct snd_pcm_substream *substream)
286 {
287 	struct dummy_systimer_pcm *dpcm = substream->runtime->private_data;
288 	spin_lock(&dpcm->lock);
289 	del_timer(&dpcm->timer);
290 	spin_unlock(&dpcm->lock);
291 	return 0;
292 }
293 
294 static int dummy_systimer_prepare(struct snd_pcm_substream *substream)
295 {
296 	struct snd_pcm_runtime *runtime = substream->runtime;
297 	struct dummy_systimer_pcm *dpcm = runtime->private_data;
298 
299 	dpcm->frac_pos = 0;
300 	dpcm->rate = runtime->rate;
301 	dpcm->frac_buffer_size = runtime->buffer_size * HZ;
302 	dpcm->frac_period_size = runtime->period_size * HZ;
303 	dpcm->frac_period_rest = dpcm->frac_period_size;
304 	dpcm->elapsed = 0;
305 
306 	return 0;
307 }
308 
309 static void dummy_systimer_callback(struct timer_list *t)
310 {
311 	struct dummy_systimer_pcm *dpcm = from_timer(dpcm, t, timer);
312 	unsigned long flags;
313 	int elapsed = 0;
314 
315 	spin_lock_irqsave(&dpcm->lock, flags);
316 	dummy_systimer_update(dpcm);
317 	dummy_systimer_rearm(dpcm);
318 	elapsed = dpcm->elapsed;
319 	dpcm->elapsed = 0;
320 	spin_unlock_irqrestore(&dpcm->lock, flags);
321 	if (elapsed)
322 		snd_pcm_period_elapsed(dpcm->substream);
323 }
324 
325 static snd_pcm_uframes_t
326 dummy_systimer_pointer(struct snd_pcm_substream *substream)
327 {
328 	struct dummy_systimer_pcm *dpcm = substream->runtime->private_data;
329 	snd_pcm_uframes_t pos;
330 
331 	spin_lock(&dpcm->lock);
332 	dummy_systimer_update(dpcm);
333 	pos = dpcm->frac_pos / HZ;
334 	spin_unlock(&dpcm->lock);
335 	return pos;
336 }
337 
338 static int dummy_systimer_create(struct snd_pcm_substream *substream)
339 {
340 	struct dummy_systimer_pcm *dpcm;
341 
342 	dpcm = kzalloc(sizeof(*dpcm), GFP_KERNEL);
343 	if (!dpcm)
344 		return -ENOMEM;
345 	substream->runtime->private_data = dpcm;
346 	timer_setup(&dpcm->timer, dummy_systimer_callback, 0);
347 	spin_lock_init(&dpcm->lock);
348 	dpcm->substream = substream;
349 	return 0;
350 }
351 
352 static void dummy_systimer_free(struct snd_pcm_substream *substream)
353 {
354 	kfree(substream->runtime->private_data);
355 }
356 
357 static const struct dummy_timer_ops dummy_systimer_ops = {
358 	.create =	dummy_systimer_create,
359 	.free =		dummy_systimer_free,
360 	.prepare =	dummy_systimer_prepare,
361 	.start =	dummy_systimer_start,
362 	.stop =		dummy_systimer_stop,
363 	.pointer =	dummy_systimer_pointer,
364 };
365 
366 #ifdef CONFIG_HIGH_RES_TIMERS
367 /*
368  * hrtimer interface
369  */
370 
371 struct dummy_hrtimer_pcm {
372 	/* ops must be the first item */
373 	const struct dummy_timer_ops *timer_ops;
374 	ktime_t base_time;
375 	ktime_t period_time;
376 	atomic_t running;
377 	struct hrtimer timer;
378 	struct snd_pcm_substream *substream;
379 };
380 
381 static enum hrtimer_restart dummy_hrtimer_callback(struct hrtimer *timer)
382 {
383 	struct dummy_hrtimer_pcm *dpcm;
384 
385 	dpcm = container_of(timer, struct dummy_hrtimer_pcm, timer);
386 	if (!atomic_read(&dpcm->running))
387 		return HRTIMER_NORESTART;
388 	/*
389 	 * In cases of XRUN and draining, this calls .trigger to stop PCM
390 	 * substream.
391 	 */
392 	snd_pcm_period_elapsed(dpcm->substream);
393 	if (!atomic_read(&dpcm->running))
394 		return HRTIMER_NORESTART;
395 
396 	hrtimer_forward_now(timer, dpcm->period_time);
397 	return HRTIMER_RESTART;
398 }
399 
400 static int dummy_hrtimer_start(struct snd_pcm_substream *substream)
401 {
402 	struct dummy_hrtimer_pcm *dpcm = substream->runtime->private_data;
403 
404 	dpcm->base_time = hrtimer_cb_get_time(&dpcm->timer);
405 	hrtimer_start(&dpcm->timer, dpcm->period_time, HRTIMER_MODE_REL_SOFT);
406 	atomic_set(&dpcm->running, 1);
407 	return 0;
408 }
409 
410 static int dummy_hrtimer_stop(struct snd_pcm_substream *substream)
411 {
412 	struct dummy_hrtimer_pcm *dpcm = substream->runtime->private_data;
413 
414 	atomic_set(&dpcm->running, 0);
415 	if (!hrtimer_callback_running(&dpcm->timer))
416 		hrtimer_cancel(&dpcm->timer);
417 	return 0;
418 }
419 
420 static inline void dummy_hrtimer_sync(struct dummy_hrtimer_pcm *dpcm)
421 {
422 	hrtimer_cancel(&dpcm->timer);
423 }
424 
425 static snd_pcm_uframes_t
426 dummy_hrtimer_pointer(struct snd_pcm_substream *substream)
427 {
428 	struct snd_pcm_runtime *runtime = substream->runtime;
429 	struct dummy_hrtimer_pcm *dpcm = runtime->private_data;
430 	u64 delta;
431 	u32 pos;
432 
433 	delta = ktime_us_delta(hrtimer_cb_get_time(&dpcm->timer),
434 			       dpcm->base_time);
435 	delta = div_u64(delta * runtime->rate + 999999, 1000000);
436 	div_u64_rem(delta, runtime->buffer_size, &pos);
437 	return pos;
438 }
439 
440 static int dummy_hrtimer_prepare(struct snd_pcm_substream *substream)
441 {
442 	struct snd_pcm_runtime *runtime = substream->runtime;
443 	struct dummy_hrtimer_pcm *dpcm = runtime->private_data;
444 	unsigned int period, rate;
445 	long sec;
446 	unsigned long nsecs;
447 
448 	dummy_hrtimer_sync(dpcm);
449 	period = runtime->period_size;
450 	rate = runtime->rate;
451 	sec = period / rate;
452 	period %= rate;
453 	nsecs = div_u64((u64)period * 1000000000UL + rate - 1, rate);
454 	dpcm->period_time = ktime_set(sec, nsecs);
455 
456 	return 0;
457 }
458 
459 static int dummy_hrtimer_create(struct snd_pcm_substream *substream)
460 {
461 	struct dummy_hrtimer_pcm *dpcm;
462 
463 	dpcm = kzalloc(sizeof(*dpcm), GFP_KERNEL);
464 	if (!dpcm)
465 		return -ENOMEM;
466 	substream->runtime->private_data = dpcm;
467 	hrtimer_init(&dpcm->timer, CLOCK_MONOTONIC, HRTIMER_MODE_REL_SOFT);
468 	dpcm->timer.function = dummy_hrtimer_callback;
469 	dpcm->substream = substream;
470 	atomic_set(&dpcm->running, 0);
471 	return 0;
472 }
473 
474 static void dummy_hrtimer_free(struct snd_pcm_substream *substream)
475 {
476 	struct dummy_hrtimer_pcm *dpcm = substream->runtime->private_data;
477 	dummy_hrtimer_sync(dpcm);
478 	kfree(dpcm);
479 }
480 
481 static const struct dummy_timer_ops dummy_hrtimer_ops = {
482 	.create =	dummy_hrtimer_create,
483 	.free =		dummy_hrtimer_free,
484 	.prepare =	dummy_hrtimer_prepare,
485 	.start =	dummy_hrtimer_start,
486 	.stop =		dummy_hrtimer_stop,
487 	.pointer =	dummy_hrtimer_pointer,
488 };
489 
490 #endif /* CONFIG_HIGH_RES_TIMERS */
491 
492 /*
493  * PCM interface
494  */
495 
496 static int dummy_pcm_trigger(struct snd_pcm_substream *substream, int cmd)
497 {
498 	switch (cmd) {
499 	case SNDRV_PCM_TRIGGER_START:
500 	case SNDRV_PCM_TRIGGER_RESUME:
501 		return get_dummy_ops(substream)->start(substream);
502 	case SNDRV_PCM_TRIGGER_STOP:
503 	case SNDRV_PCM_TRIGGER_SUSPEND:
504 		return get_dummy_ops(substream)->stop(substream);
505 	}
506 	return -EINVAL;
507 }
508 
509 static int dummy_pcm_prepare(struct snd_pcm_substream *substream)
510 {
511 	return get_dummy_ops(substream)->prepare(substream);
512 }
513 
514 static snd_pcm_uframes_t dummy_pcm_pointer(struct snd_pcm_substream *substream)
515 {
516 	return get_dummy_ops(substream)->pointer(substream);
517 }
518 
519 static const struct snd_pcm_hardware dummy_pcm_hardware = {
520 	.info =			(SNDRV_PCM_INFO_MMAP |
521 				 SNDRV_PCM_INFO_INTERLEAVED |
522 				 SNDRV_PCM_INFO_RESUME |
523 				 SNDRV_PCM_INFO_MMAP_VALID),
524 	.formats =		USE_FORMATS,
525 	.rates =		USE_RATE,
526 	.rate_min =		USE_RATE_MIN,
527 	.rate_max =		USE_RATE_MAX,
528 	.channels_min =		USE_CHANNELS_MIN,
529 	.channels_max =		USE_CHANNELS_MAX,
530 	.buffer_bytes_max =	MAX_BUFFER_SIZE,
531 	.period_bytes_min =	MIN_PERIOD_SIZE,
532 	.period_bytes_max =	MAX_PERIOD_SIZE,
533 	.periods_min =		USE_PERIODS_MIN,
534 	.periods_max =		USE_PERIODS_MAX,
535 	.fifo_size =		0,
536 };
537 
538 static int dummy_pcm_hw_params(struct snd_pcm_substream *substream,
539 			       struct snd_pcm_hw_params *hw_params)
540 {
541 	if (fake_buffer) {
542 		/* runtime->dma_bytes has to be set manually to allow mmap */
543 		substream->runtime->dma_bytes = params_buffer_bytes(hw_params);
544 		return 0;
545 	}
546 	return snd_pcm_lib_malloc_pages(substream,
547 					params_buffer_bytes(hw_params));
548 }
549 
550 static int dummy_pcm_hw_free(struct snd_pcm_substream *substream)
551 {
552 	if (fake_buffer)
553 		return 0;
554 	return snd_pcm_lib_free_pages(substream);
555 }
556 
557 static int dummy_pcm_open(struct snd_pcm_substream *substream)
558 {
559 	struct snd_dummy *dummy = snd_pcm_substream_chip(substream);
560 	struct dummy_model *model = dummy->model;
561 	struct snd_pcm_runtime *runtime = substream->runtime;
562 	const struct dummy_timer_ops *ops;
563 	int err;
564 
565 	ops = &dummy_systimer_ops;
566 #ifdef CONFIG_HIGH_RES_TIMERS
567 	if (hrtimer)
568 		ops = &dummy_hrtimer_ops;
569 #endif
570 
571 	err = ops->create(substream);
572 	if (err < 0)
573 		return err;
574 	get_dummy_ops(substream) = ops;
575 
576 	runtime->hw = dummy->pcm_hw;
577 	if (substream->pcm->device & 1) {
578 		runtime->hw.info &= ~SNDRV_PCM_INFO_INTERLEAVED;
579 		runtime->hw.info |= SNDRV_PCM_INFO_NONINTERLEAVED;
580 	}
581 	if (substream->pcm->device & 2)
582 		runtime->hw.info &= ~(SNDRV_PCM_INFO_MMAP |
583 				      SNDRV_PCM_INFO_MMAP_VALID);
584 
585 	if (model == NULL)
586 		return 0;
587 
588 	if (substream->stream == SNDRV_PCM_STREAM_PLAYBACK) {
589 		if (model->playback_constraints)
590 			err = model->playback_constraints(substream->runtime);
591 	} else {
592 		if (model->capture_constraints)
593 			err = model->capture_constraints(substream->runtime);
594 	}
595 	if (err < 0) {
596 		get_dummy_ops(substream)->free(substream);
597 		return err;
598 	}
599 	return 0;
600 }
601 
602 static int dummy_pcm_close(struct snd_pcm_substream *substream)
603 {
604 	get_dummy_ops(substream)->free(substream);
605 	return 0;
606 }
607 
608 /*
609  * dummy buffer handling
610  */
611 
612 static void *dummy_page[2];
613 
614 static void free_fake_buffer(void)
615 {
616 	if (fake_buffer) {
617 		int i;
618 		for (i = 0; i < 2; i++)
619 			if (dummy_page[i]) {
620 				free_page((unsigned long)dummy_page[i]);
621 				dummy_page[i] = NULL;
622 			}
623 	}
624 }
625 
626 static int alloc_fake_buffer(void)
627 {
628 	int i;
629 
630 	if (!fake_buffer)
631 		return 0;
632 	for (i = 0; i < 2; i++) {
633 		dummy_page[i] = (void *)get_zeroed_page(GFP_KERNEL);
634 		if (!dummy_page[i]) {
635 			free_fake_buffer();
636 			return -ENOMEM;
637 		}
638 	}
639 	return 0;
640 }
641 
642 static int dummy_pcm_copy(struct snd_pcm_substream *substream,
643 			  int channel, unsigned long pos,
644 			  void __user *dst, unsigned long bytes)
645 {
646 	return 0; /* do nothing */
647 }
648 
649 static int dummy_pcm_copy_kernel(struct snd_pcm_substream *substream,
650 				 int channel, unsigned long pos,
651 				 void *dst, unsigned long bytes)
652 {
653 	return 0; /* do nothing */
654 }
655 
656 static int dummy_pcm_silence(struct snd_pcm_substream *substream,
657 			     int channel, unsigned long pos,
658 			     unsigned long bytes)
659 {
660 	return 0; /* do nothing */
661 }
662 
663 static struct page *dummy_pcm_page(struct snd_pcm_substream *substream,
664 				   unsigned long offset)
665 {
666 	return virt_to_page(dummy_page[substream->stream]); /* the same page */
667 }
668 
669 static struct snd_pcm_ops dummy_pcm_ops = {
670 	.open =		dummy_pcm_open,
671 	.close =	dummy_pcm_close,
672 	.ioctl =	snd_pcm_lib_ioctl,
673 	.hw_params =	dummy_pcm_hw_params,
674 	.hw_free =	dummy_pcm_hw_free,
675 	.prepare =	dummy_pcm_prepare,
676 	.trigger =	dummy_pcm_trigger,
677 	.pointer =	dummy_pcm_pointer,
678 };
679 
680 static struct snd_pcm_ops dummy_pcm_ops_no_buf = {
681 	.open =		dummy_pcm_open,
682 	.close =	dummy_pcm_close,
683 	.ioctl =	snd_pcm_lib_ioctl,
684 	.hw_params =	dummy_pcm_hw_params,
685 	.hw_free =	dummy_pcm_hw_free,
686 	.prepare =	dummy_pcm_prepare,
687 	.trigger =	dummy_pcm_trigger,
688 	.pointer =	dummy_pcm_pointer,
689 	.copy_user =	dummy_pcm_copy,
690 	.copy_kernel =	dummy_pcm_copy_kernel,
691 	.fill_silence =	dummy_pcm_silence,
692 	.page =		dummy_pcm_page,
693 };
694 
695 static int snd_card_dummy_pcm(struct snd_dummy *dummy, int device,
696 			      int substreams)
697 {
698 	struct snd_pcm *pcm;
699 	struct snd_pcm_ops *ops;
700 	int err;
701 
702 	err = snd_pcm_new(dummy->card, "Dummy PCM", device,
703 			       substreams, substreams, &pcm);
704 	if (err < 0)
705 		return err;
706 	dummy->pcm = pcm;
707 	if (fake_buffer)
708 		ops = &dummy_pcm_ops_no_buf;
709 	else
710 		ops = &dummy_pcm_ops;
711 	snd_pcm_set_ops(pcm, SNDRV_PCM_STREAM_PLAYBACK, ops);
712 	snd_pcm_set_ops(pcm, SNDRV_PCM_STREAM_CAPTURE, ops);
713 	pcm->private_data = dummy;
714 	pcm->info_flags = 0;
715 	strcpy(pcm->name, "Dummy PCM");
716 	if (!fake_buffer) {
717 		snd_pcm_lib_preallocate_pages_for_all(pcm,
718 			SNDRV_DMA_TYPE_CONTINUOUS,
719 			snd_dma_continuous_data(GFP_KERNEL),
720 			0, 64*1024);
721 	}
722 	return 0;
723 }
724 
725 /*
726  * mixer interface
727  */
728 
729 #define DUMMY_VOLUME(xname, xindex, addr) \
730 { .iface = SNDRV_CTL_ELEM_IFACE_MIXER, \
731   .access = SNDRV_CTL_ELEM_ACCESS_READWRITE | SNDRV_CTL_ELEM_ACCESS_TLV_READ, \
732   .name = xname, .index = xindex, \
733   .info = snd_dummy_volume_info, \
734   .get = snd_dummy_volume_get, .put = snd_dummy_volume_put, \
735   .private_value = addr, \
736   .tlv = { .p = db_scale_dummy } }
737 
738 static int snd_dummy_volume_info(struct snd_kcontrol *kcontrol,
739 				 struct snd_ctl_elem_info *uinfo)
740 {
741 	uinfo->type = SNDRV_CTL_ELEM_TYPE_INTEGER;
742 	uinfo->count = 2;
743 	uinfo->value.integer.min = -50;
744 	uinfo->value.integer.max = 100;
745 	return 0;
746 }
747 
748 static int snd_dummy_volume_get(struct snd_kcontrol *kcontrol,
749 				struct snd_ctl_elem_value *ucontrol)
750 {
751 	struct snd_dummy *dummy = snd_kcontrol_chip(kcontrol);
752 	int addr = kcontrol->private_value;
753 
754 	spin_lock_irq(&dummy->mixer_lock);
755 	ucontrol->value.integer.value[0] = dummy->mixer_volume[addr][0];
756 	ucontrol->value.integer.value[1] = dummy->mixer_volume[addr][1];
757 	spin_unlock_irq(&dummy->mixer_lock);
758 	return 0;
759 }
760 
761 static int snd_dummy_volume_put(struct snd_kcontrol *kcontrol,
762 				struct snd_ctl_elem_value *ucontrol)
763 {
764 	struct snd_dummy *dummy = snd_kcontrol_chip(kcontrol);
765 	int change, addr = kcontrol->private_value;
766 	int left, right;
767 
768 	left = ucontrol->value.integer.value[0];
769 	if (left < -50)
770 		left = -50;
771 	if (left > 100)
772 		left = 100;
773 	right = ucontrol->value.integer.value[1];
774 	if (right < -50)
775 		right = -50;
776 	if (right > 100)
777 		right = 100;
778 	spin_lock_irq(&dummy->mixer_lock);
779 	change = dummy->mixer_volume[addr][0] != left ||
780 	         dummy->mixer_volume[addr][1] != right;
781 	dummy->mixer_volume[addr][0] = left;
782 	dummy->mixer_volume[addr][1] = right;
783 	spin_unlock_irq(&dummy->mixer_lock);
784 	return change;
785 }
786 
787 static const DECLARE_TLV_DB_SCALE(db_scale_dummy, -4500, 30, 0);
788 
789 #define DUMMY_CAPSRC(xname, xindex, addr) \
790 { .iface = SNDRV_CTL_ELEM_IFACE_MIXER, .name = xname, .index = xindex, \
791   .info = snd_dummy_capsrc_info, \
792   .get = snd_dummy_capsrc_get, .put = snd_dummy_capsrc_put, \
793   .private_value = addr }
794 
795 #define snd_dummy_capsrc_info	snd_ctl_boolean_stereo_info
796 
797 static int snd_dummy_capsrc_get(struct snd_kcontrol *kcontrol,
798 				struct snd_ctl_elem_value *ucontrol)
799 {
800 	struct snd_dummy *dummy = snd_kcontrol_chip(kcontrol);
801 	int addr = kcontrol->private_value;
802 
803 	spin_lock_irq(&dummy->mixer_lock);
804 	ucontrol->value.integer.value[0] = dummy->capture_source[addr][0];
805 	ucontrol->value.integer.value[1] = dummy->capture_source[addr][1];
806 	spin_unlock_irq(&dummy->mixer_lock);
807 	return 0;
808 }
809 
810 static int snd_dummy_capsrc_put(struct snd_kcontrol *kcontrol, struct snd_ctl_elem_value *ucontrol)
811 {
812 	struct snd_dummy *dummy = snd_kcontrol_chip(kcontrol);
813 	int change, addr = kcontrol->private_value;
814 	int left, right;
815 
816 	left = ucontrol->value.integer.value[0] & 1;
817 	right = ucontrol->value.integer.value[1] & 1;
818 	spin_lock_irq(&dummy->mixer_lock);
819 	change = dummy->capture_source[addr][0] != left &&
820 	         dummy->capture_source[addr][1] != right;
821 	dummy->capture_source[addr][0] = left;
822 	dummy->capture_source[addr][1] = right;
823 	spin_unlock_irq(&dummy->mixer_lock);
824 	return change;
825 }
826 
827 static int snd_dummy_iobox_info(struct snd_kcontrol *kcontrol,
828 				struct snd_ctl_elem_info *info)
829 {
830 	static const char *const names[] = { "None", "CD Player" };
831 
832 	return snd_ctl_enum_info(info, 1, 2, names);
833 }
834 
835 static int snd_dummy_iobox_get(struct snd_kcontrol *kcontrol,
836 			       struct snd_ctl_elem_value *value)
837 {
838 	struct snd_dummy *dummy = snd_kcontrol_chip(kcontrol);
839 
840 	value->value.enumerated.item[0] = dummy->iobox;
841 	return 0;
842 }
843 
844 static int snd_dummy_iobox_put(struct snd_kcontrol *kcontrol,
845 			       struct snd_ctl_elem_value *value)
846 {
847 	struct snd_dummy *dummy = snd_kcontrol_chip(kcontrol);
848 	int changed;
849 
850 	if (value->value.enumerated.item[0] > 1)
851 		return -EINVAL;
852 
853 	changed = value->value.enumerated.item[0] != dummy->iobox;
854 	if (changed) {
855 		dummy->iobox = value->value.enumerated.item[0];
856 
857 		if (dummy->iobox) {
858 			dummy->cd_volume_ctl->vd[0].access &=
859 				~SNDRV_CTL_ELEM_ACCESS_INACTIVE;
860 			dummy->cd_switch_ctl->vd[0].access &=
861 				~SNDRV_CTL_ELEM_ACCESS_INACTIVE;
862 		} else {
863 			dummy->cd_volume_ctl->vd[0].access |=
864 				SNDRV_CTL_ELEM_ACCESS_INACTIVE;
865 			dummy->cd_switch_ctl->vd[0].access |=
866 				SNDRV_CTL_ELEM_ACCESS_INACTIVE;
867 		}
868 
869 		snd_ctl_notify(dummy->card, SNDRV_CTL_EVENT_MASK_INFO,
870 			       &dummy->cd_volume_ctl->id);
871 		snd_ctl_notify(dummy->card, SNDRV_CTL_EVENT_MASK_INFO,
872 			       &dummy->cd_switch_ctl->id);
873 	}
874 
875 	return changed;
876 }
877 
878 static struct snd_kcontrol_new snd_dummy_controls[] = {
879 DUMMY_VOLUME("Master Volume", 0, MIXER_ADDR_MASTER),
880 DUMMY_CAPSRC("Master Capture Switch", 0, MIXER_ADDR_MASTER),
881 DUMMY_VOLUME("Synth Volume", 0, MIXER_ADDR_SYNTH),
882 DUMMY_CAPSRC("Synth Capture Switch", 0, MIXER_ADDR_SYNTH),
883 DUMMY_VOLUME("Line Volume", 0, MIXER_ADDR_LINE),
884 DUMMY_CAPSRC("Line Capture Switch", 0, MIXER_ADDR_LINE),
885 DUMMY_VOLUME("Mic Volume", 0, MIXER_ADDR_MIC),
886 DUMMY_CAPSRC("Mic Capture Switch", 0, MIXER_ADDR_MIC),
887 DUMMY_VOLUME("CD Volume", 0, MIXER_ADDR_CD),
888 DUMMY_CAPSRC("CD Capture Switch", 0, MIXER_ADDR_CD),
889 {
890 	.iface = SNDRV_CTL_ELEM_IFACE_MIXER,
891 	.name  = "External I/O Box",
892 	.info  = snd_dummy_iobox_info,
893 	.get   = snd_dummy_iobox_get,
894 	.put   = snd_dummy_iobox_put,
895 },
896 };
897 
898 static int snd_card_dummy_new_mixer(struct snd_dummy *dummy)
899 {
900 	struct snd_card *card = dummy->card;
901 	struct snd_kcontrol *kcontrol;
902 	unsigned int idx;
903 	int err;
904 
905 	spin_lock_init(&dummy->mixer_lock);
906 	strcpy(card->mixername, "Dummy Mixer");
907 	dummy->iobox = 1;
908 
909 	for (idx = 0; idx < ARRAY_SIZE(snd_dummy_controls); idx++) {
910 		kcontrol = snd_ctl_new1(&snd_dummy_controls[idx], dummy);
911 		err = snd_ctl_add(card, kcontrol);
912 		if (err < 0)
913 			return err;
914 		if (!strcmp(kcontrol->id.name, "CD Volume"))
915 			dummy->cd_volume_ctl = kcontrol;
916 		else if (!strcmp(kcontrol->id.name, "CD Capture Switch"))
917 			dummy->cd_switch_ctl = kcontrol;
918 
919 	}
920 	return 0;
921 }
922 
923 #if defined(CONFIG_SND_DEBUG) && defined(CONFIG_SND_PROC_FS)
924 /*
925  * proc interface
926  */
927 static void print_formats(struct snd_dummy *dummy,
928 			  struct snd_info_buffer *buffer)
929 {
930 	int i;
931 
932 	for (i = 0; i < SNDRV_PCM_FORMAT_LAST; i++) {
933 		if (dummy->pcm_hw.formats & (1ULL << i))
934 			snd_iprintf(buffer, " %s", snd_pcm_format_name(i));
935 	}
936 }
937 
938 static void print_rates(struct snd_dummy *dummy,
939 			struct snd_info_buffer *buffer)
940 {
941 	static int rates[] = {
942 		5512, 8000, 11025, 16000, 22050, 32000, 44100, 48000,
943 		64000, 88200, 96000, 176400, 192000,
944 	};
945 	int i;
946 
947 	if (dummy->pcm_hw.rates & SNDRV_PCM_RATE_CONTINUOUS)
948 		snd_iprintf(buffer, " continuous");
949 	if (dummy->pcm_hw.rates & SNDRV_PCM_RATE_KNOT)
950 		snd_iprintf(buffer, " knot");
951 	for (i = 0; i < ARRAY_SIZE(rates); i++)
952 		if (dummy->pcm_hw.rates & (1 << i))
953 			snd_iprintf(buffer, " %d", rates[i]);
954 }
955 
956 #define get_dummy_int_ptr(dummy, ofs) \
957 	(unsigned int *)((char *)&((dummy)->pcm_hw) + (ofs))
958 #define get_dummy_ll_ptr(dummy, ofs) \
959 	(unsigned long long *)((char *)&((dummy)->pcm_hw) + (ofs))
960 
961 struct dummy_hw_field {
962 	const char *name;
963 	const char *format;
964 	unsigned int offset;
965 	unsigned int size;
966 };
967 #define FIELD_ENTRY(item, fmt) {		   \
968 	.name = #item,				   \
969 	.format = fmt,				   \
970 	.offset = offsetof(struct snd_pcm_hardware, item), \
971 	.size = sizeof(dummy_pcm_hardware.item) }
972 
973 static struct dummy_hw_field fields[] = {
974 	FIELD_ENTRY(formats, "%#llx"),
975 	FIELD_ENTRY(rates, "%#x"),
976 	FIELD_ENTRY(rate_min, "%d"),
977 	FIELD_ENTRY(rate_max, "%d"),
978 	FIELD_ENTRY(channels_min, "%d"),
979 	FIELD_ENTRY(channels_max, "%d"),
980 	FIELD_ENTRY(buffer_bytes_max, "%ld"),
981 	FIELD_ENTRY(period_bytes_min, "%ld"),
982 	FIELD_ENTRY(period_bytes_max, "%ld"),
983 	FIELD_ENTRY(periods_min, "%d"),
984 	FIELD_ENTRY(periods_max, "%d"),
985 };
986 
987 static void dummy_proc_read(struct snd_info_entry *entry,
988 			    struct snd_info_buffer *buffer)
989 {
990 	struct snd_dummy *dummy = entry->private_data;
991 	int i;
992 
993 	for (i = 0; i < ARRAY_SIZE(fields); i++) {
994 		snd_iprintf(buffer, "%s ", fields[i].name);
995 		if (fields[i].size == sizeof(int))
996 			snd_iprintf(buffer, fields[i].format,
997 				*get_dummy_int_ptr(dummy, fields[i].offset));
998 		else
999 			snd_iprintf(buffer, fields[i].format,
1000 				*get_dummy_ll_ptr(dummy, fields[i].offset));
1001 		if (!strcmp(fields[i].name, "formats"))
1002 			print_formats(dummy, buffer);
1003 		else if (!strcmp(fields[i].name, "rates"))
1004 			print_rates(dummy, buffer);
1005 		snd_iprintf(buffer, "\n");
1006 	}
1007 }
1008 
1009 static void dummy_proc_write(struct snd_info_entry *entry,
1010 			     struct snd_info_buffer *buffer)
1011 {
1012 	struct snd_dummy *dummy = entry->private_data;
1013 	char line[64];
1014 
1015 	while (!snd_info_get_line(buffer, line, sizeof(line))) {
1016 		char item[20];
1017 		const char *ptr;
1018 		unsigned long long val;
1019 		int i;
1020 
1021 		ptr = snd_info_get_str(item, line, sizeof(item));
1022 		for (i = 0; i < ARRAY_SIZE(fields); i++) {
1023 			if (!strcmp(item, fields[i].name))
1024 				break;
1025 		}
1026 		if (i >= ARRAY_SIZE(fields))
1027 			continue;
1028 		snd_info_get_str(item, ptr, sizeof(item));
1029 		if (kstrtoull(item, 0, &val))
1030 			continue;
1031 		if (fields[i].size == sizeof(int))
1032 			*get_dummy_int_ptr(dummy, fields[i].offset) = val;
1033 		else
1034 			*get_dummy_ll_ptr(dummy, fields[i].offset) = val;
1035 	}
1036 }
1037 
1038 static void dummy_proc_init(struct snd_dummy *chip)
1039 {
1040 	struct snd_info_entry *entry;
1041 
1042 	if (!snd_card_proc_new(chip->card, "dummy_pcm", &entry)) {
1043 		snd_info_set_text_ops(entry, chip, dummy_proc_read);
1044 		entry->c.text.write = dummy_proc_write;
1045 		entry->mode |= S_IWUSR;
1046 		entry->private_data = chip;
1047 	}
1048 }
1049 #else
1050 #define dummy_proc_init(x)
1051 #endif /* CONFIG_SND_DEBUG && CONFIG_SND_PROC_FS */
1052 
1053 static int snd_dummy_probe(struct platform_device *devptr)
1054 {
1055 	struct snd_card *card;
1056 	struct snd_dummy *dummy;
1057 	struct dummy_model *m = NULL, **mdl;
1058 	int idx, err;
1059 	int dev = devptr->id;
1060 
1061 	err = snd_card_new(&devptr->dev, index[dev], id[dev], THIS_MODULE,
1062 			   sizeof(struct snd_dummy), &card);
1063 	if (err < 0)
1064 		return err;
1065 	dummy = card->private_data;
1066 	dummy->card = card;
1067 	for (mdl = dummy_models; *mdl && model[dev]; mdl++) {
1068 		if (strcmp(model[dev], (*mdl)->name) == 0) {
1069 			printk(KERN_INFO
1070 				"snd-dummy: Using model '%s' for card %i\n",
1071 				(*mdl)->name, card->number);
1072 			m = dummy->model = *mdl;
1073 			break;
1074 		}
1075 	}
1076 	for (idx = 0; idx < MAX_PCM_DEVICES && idx < pcm_devs[dev]; idx++) {
1077 		if (pcm_substreams[dev] < 1)
1078 			pcm_substreams[dev] = 1;
1079 		if (pcm_substreams[dev] > MAX_PCM_SUBSTREAMS)
1080 			pcm_substreams[dev] = MAX_PCM_SUBSTREAMS;
1081 		err = snd_card_dummy_pcm(dummy, idx, pcm_substreams[dev]);
1082 		if (err < 0)
1083 			goto __nodev;
1084 	}
1085 
1086 	dummy->pcm_hw = dummy_pcm_hardware;
1087 	if (m) {
1088 		if (m->formats)
1089 			dummy->pcm_hw.formats = m->formats;
1090 		if (m->buffer_bytes_max)
1091 			dummy->pcm_hw.buffer_bytes_max = m->buffer_bytes_max;
1092 		if (m->period_bytes_min)
1093 			dummy->pcm_hw.period_bytes_min = m->period_bytes_min;
1094 		if (m->period_bytes_max)
1095 			dummy->pcm_hw.period_bytes_max = m->period_bytes_max;
1096 		if (m->periods_min)
1097 			dummy->pcm_hw.periods_min = m->periods_min;
1098 		if (m->periods_max)
1099 			dummy->pcm_hw.periods_max = m->periods_max;
1100 		if (m->rates)
1101 			dummy->pcm_hw.rates = m->rates;
1102 		if (m->rate_min)
1103 			dummy->pcm_hw.rate_min = m->rate_min;
1104 		if (m->rate_max)
1105 			dummy->pcm_hw.rate_max = m->rate_max;
1106 		if (m->channels_min)
1107 			dummy->pcm_hw.channels_min = m->channels_min;
1108 		if (m->channels_max)
1109 			dummy->pcm_hw.channels_max = m->channels_max;
1110 	}
1111 
1112 	err = snd_card_dummy_new_mixer(dummy);
1113 	if (err < 0)
1114 		goto __nodev;
1115 	strcpy(card->driver, "Dummy");
1116 	strcpy(card->shortname, "Dummy");
1117 	sprintf(card->longname, "Dummy %i", dev + 1);
1118 
1119 	dummy_proc_init(dummy);
1120 
1121 	err = snd_card_register(card);
1122 	if (err == 0) {
1123 		platform_set_drvdata(devptr, card);
1124 		return 0;
1125 	}
1126       __nodev:
1127 	snd_card_free(card);
1128 	return err;
1129 }
1130 
1131 static int snd_dummy_remove(struct platform_device *devptr)
1132 {
1133 	snd_card_free(platform_get_drvdata(devptr));
1134 	return 0;
1135 }
1136 
1137 #ifdef CONFIG_PM_SLEEP
1138 static int snd_dummy_suspend(struct device *pdev)
1139 {
1140 	struct snd_card *card = dev_get_drvdata(pdev);
1141 	struct snd_dummy *dummy = card->private_data;
1142 
1143 	snd_power_change_state(card, SNDRV_CTL_POWER_D3hot);
1144 	snd_pcm_suspend_all(dummy->pcm);
1145 	return 0;
1146 }
1147 
1148 static int snd_dummy_resume(struct device *pdev)
1149 {
1150 	struct snd_card *card = dev_get_drvdata(pdev);
1151 
1152 	snd_power_change_state(card, SNDRV_CTL_POWER_D0);
1153 	return 0;
1154 }
1155 
1156 static SIMPLE_DEV_PM_OPS(snd_dummy_pm, snd_dummy_suspend, snd_dummy_resume);
1157 #define SND_DUMMY_PM_OPS	&snd_dummy_pm
1158 #else
1159 #define SND_DUMMY_PM_OPS	NULL
1160 #endif
1161 
1162 #define SND_DUMMY_DRIVER	"snd_dummy"
1163 
1164 static struct platform_driver snd_dummy_driver = {
1165 	.probe		= snd_dummy_probe,
1166 	.remove		= snd_dummy_remove,
1167 	.driver		= {
1168 		.name	= SND_DUMMY_DRIVER,
1169 		.pm	= SND_DUMMY_PM_OPS,
1170 	},
1171 };
1172 
1173 static void snd_dummy_unregister_all(void)
1174 {
1175 	int i;
1176 
1177 	for (i = 0; i < ARRAY_SIZE(devices); ++i)
1178 		platform_device_unregister(devices[i]);
1179 	platform_driver_unregister(&snd_dummy_driver);
1180 	free_fake_buffer();
1181 }
1182 
1183 static int __init alsa_card_dummy_init(void)
1184 {
1185 	int i, cards, err;
1186 
1187 	err = platform_driver_register(&snd_dummy_driver);
1188 	if (err < 0)
1189 		return err;
1190 
1191 	err = alloc_fake_buffer();
1192 	if (err < 0) {
1193 		platform_driver_unregister(&snd_dummy_driver);
1194 		return err;
1195 	}
1196 
1197 	cards = 0;
1198 	for (i = 0; i < SNDRV_CARDS; i++) {
1199 		struct platform_device *device;
1200 		if (! enable[i])
1201 			continue;
1202 		device = platform_device_register_simple(SND_DUMMY_DRIVER,
1203 							 i, NULL, 0);
1204 		if (IS_ERR(device))
1205 			continue;
1206 		if (!platform_get_drvdata(device)) {
1207 			platform_device_unregister(device);
1208 			continue;
1209 		}
1210 		devices[i] = device;
1211 		cards++;
1212 	}
1213 	if (!cards) {
1214 #ifdef MODULE
1215 		printk(KERN_ERR "Dummy soundcard not found or device busy\n");
1216 #endif
1217 		snd_dummy_unregister_all();
1218 		return -ENODEV;
1219 	}
1220 	return 0;
1221 }
1222 
1223 static void __exit alsa_card_dummy_exit(void)
1224 {
1225 	snd_dummy_unregister_all();
1226 }
1227 
1228 module_init(alsa_card_dummy_init)
1229 module_exit(alsa_card_dummy_exit)
1230