xref: /openbmc/linux/sound/drivers/dummy.c (revision 8684014d)
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 struct dummy_model {
113 	const char *name;
114 	int (*playback_constraints)(struct snd_pcm_runtime *runtime);
115 	int (*capture_constraints)(struct snd_pcm_runtime *runtime);
116 	u64 formats;
117 	size_t buffer_bytes_max;
118 	size_t period_bytes_min;
119 	size_t period_bytes_max;
120 	unsigned int periods_min;
121 	unsigned int periods_max;
122 	unsigned int rates;
123 	unsigned int rate_min;
124 	unsigned int rate_max;
125 	unsigned int channels_min;
126 	unsigned int channels_max;
127 };
128 
129 struct snd_dummy {
130 	struct snd_card *card;
131 	struct dummy_model *model;
132 	struct snd_pcm *pcm;
133 	struct snd_pcm_hardware pcm_hw;
134 	spinlock_t mixer_lock;
135 	int mixer_volume[MIXER_ADDR_LAST+1][2];
136 	int capture_source[MIXER_ADDR_LAST+1][2];
137 	int iobox;
138 	struct snd_kcontrol *cd_volume_ctl;
139 	struct snd_kcontrol *cd_switch_ctl;
140 	const struct dummy_timer_ops *timer_ops;
141 };
142 
143 /*
144  * card models
145  */
146 
147 static int emu10k1_playback_constraints(struct snd_pcm_runtime *runtime)
148 {
149 	int err;
150 	err = snd_pcm_hw_constraint_integer(runtime, SNDRV_PCM_HW_PARAM_PERIODS);
151 	if (err < 0)
152 		return err;
153 	err = snd_pcm_hw_constraint_minmax(runtime, SNDRV_PCM_HW_PARAM_BUFFER_BYTES, 256, UINT_MAX);
154 	if (err < 0)
155 		return err;
156 	return 0;
157 }
158 
159 struct dummy_model model_emu10k1 = {
160 	.name = "emu10k1",
161 	.playback_constraints = emu10k1_playback_constraints,
162 	.buffer_bytes_max = 128 * 1024,
163 };
164 
165 struct dummy_model model_rme9652 = {
166 	.name = "rme9652",
167 	.buffer_bytes_max = 26 * 64 * 1024,
168 	.formats = SNDRV_PCM_FMTBIT_S32_LE,
169 	.channels_min = 26,
170 	.channels_max = 26,
171 	.periods_min = 2,
172 	.periods_max = 2,
173 };
174 
175 struct dummy_model model_ice1712 = {
176 	.name = "ice1712",
177 	.buffer_bytes_max = 256 * 1024,
178 	.formats = SNDRV_PCM_FMTBIT_S32_LE,
179 	.channels_min = 10,
180 	.channels_max = 10,
181 	.periods_min = 1,
182 	.periods_max = 1024,
183 };
184 
185 struct dummy_model model_uda1341 = {
186 	.name = "uda1341",
187 	.buffer_bytes_max = 16380,
188 	.formats = SNDRV_PCM_FMTBIT_S16_LE,
189 	.channels_min = 2,
190 	.channels_max = 2,
191 	.periods_min = 2,
192 	.periods_max = 255,
193 };
194 
195 struct dummy_model model_ac97 = {
196 	.name = "ac97",
197 	.formats = SNDRV_PCM_FMTBIT_S16_LE,
198 	.channels_min = 2,
199 	.channels_max = 2,
200 	.rates = SNDRV_PCM_RATE_48000,
201 	.rate_min = 48000,
202 	.rate_max = 48000,
203 };
204 
205 struct dummy_model model_ca0106 = {
206 	.name = "ca0106",
207 	.formats = SNDRV_PCM_FMTBIT_S16_LE,
208 	.buffer_bytes_max = ((65536-64)*8),
209 	.period_bytes_max = (65536-64),
210 	.periods_min = 2,
211 	.periods_max = 8,
212 	.channels_min = 2,
213 	.channels_max = 2,
214 	.rates = SNDRV_PCM_RATE_48000|SNDRV_PCM_RATE_96000|SNDRV_PCM_RATE_192000,
215 	.rate_min = 48000,
216 	.rate_max = 192000,
217 };
218 
219 struct dummy_model *dummy_models[] = {
220 	&model_emu10k1,
221 	&model_rme9652,
222 	&model_ice1712,
223 	&model_uda1341,
224 	&model_ac97,
225 	&model_ca0106,
226 	NULL
227 };
228 
229 /*
230  * system timer interface
231  */
232 
233 struct dummy_systimer_pcm {
234 	spinlock_t lock;
235 	struct timer_list timer;
236 	unsigned long base_time;
237 	unsigned int frac_pos;	/* fractional sample position (based HZ) */
238 	unsigned int frac_period_rest;
239 	unsigned int frac_buffer_size;	/* buffer_size * HZ */
240 	unsigned int frac_period_size;	/* period_size * HZ */
241 	unsigned int rate;
242 	int elapsed;
243 	struct snd_pcm_substream *substream;
244 };
245 
246 static void dummy_systimer_rearm(struct dummy_systimer_pcm *dpcm)
247 {
248 	dpcm->timer.expires = jiffies +
249 		(dpcm->frac_period_rest + dpcm->rate - 1) / dpcm->rate;
250 	add_timer(&dpcm->timer);
251 }
252 
253 static void dummy_systimer_update(struct dummy_systimer_pcm *dpcm)
254 {
255 	unsigned long delta;
256 
257 	delta = jiffies - dpcm->base_time;
258 	if (!delta)
259 		return;
260 	dpcm->base_time += delta;
261 	delta *= dpcm->rate;
262 	dpcm->frac_pos += delta;
263 	while (dpcm->frac_pos >= dpcm->frac_buffer_size)
264 		dpcm->frac_pos -= dpcm->frac_buffer_size;
265 	while (dpcm->frac_period_rest <= delta) {
266 		dpcm->elapsed++;
267 		dpcm->frac_period_rest += dpcm->frac_period_size;
268 	}
269 	dpcm->frac_period_rest -= delta;
270 }
271 
272 static int dummy_systimer_start(struct snd_pcm_substream *substream)
273 {
274 	struct dummy_systimer_pcm *dpcm = substream->runtime->private_data;
275 	spin_lock(&dpcm->lock);
276 	dpcm->base_time = jiffies;
277 	dummy_systimer_rearm(dpcm);
278 	spin_unlock(&dpcm->lock);
279 	return 0;
280 }
281 
282 static int dummy_systimer_stop(struct snd_pcm_substream *substream)
283 {
284 	struct dummy_systimer_pcm *dpcm = substream->runtime->private_data;
285 	spin_lock(&dpcm->lock);
286 	del_timer(&dpcm->timer);
287 	spin_unlock(&dpcm->lock);
288 	return 0;
289 }
290 
291 static int dummy_systimer_prepare(struct snd_pcm_substream *substream)
292 {
293 	struct snd_pcm_runtime *runtime = substream->runtime;
294 	struct dummy_systimer_pcm *dpcm = runtime->private_data;
295 
296 	dpcm->frac_pos = 0;
297 	dpcm->rate = runtime->rate;
298 	dpcm->frac_buffer_size = runtime->buffer_size * HZ;
299 	dpcm->frac_period_size = runtime->period_size * HZ;
300 	dpcm->frac_period_rest = dpcm->frac_period_size;
301 	dpcm->elapsed = 0;
302 
303 	return 0;
304 }
305 
306 static void dummy_systimer_callback(unsigned long data)
307 {
308 	struct dummy_systimer_pcm *dpcm = (struct dummy_systimer_pcm *)data;
309 	unsigned long flags;
310 	int elapsed = 0;
311 
312 	spin_lock_irqsave(&dpcm->lock, flags);
313 	dummy_systimer_update(dpcm);
314 	dummy_systimer_rearm(dpcm);
315 	elapsed = dpcm->elapsed;
316 	dpcm->elapsed = 0;
317 	spin_unlock_irqrestore(&dpcm->lock, flags);
318 	if (elapsed)
319 		snd_pcm_period_elapsed(dpcm->substream);
320 }
321 
322 static snd_pcm_uframes_t
323 dummy_systimer_pointer(struct snd_pcm_substream *substream)
324 {
325 	struct dummy_systimer_pcm *dpcm = substream->runtime->private_data;
326 	snd_pcm_uframes_t pos;
327 
328 	spin_lock(&dpcm->lock);
329 	dummy_systimer_update(dpcm);
330 	pos = dpcm->frac_pos / HZ;
331 	spin_unlock(&dpcm->lock);
332 	return pos;
333 }
334 
335 static int dummy_systimer_create(struct snd_pcm_substream *substream)
336 {
337 	struct dummy_systimer_pcm *dpcm;
338 
339 	dpcm = kzalloc(sizeof(*dpcm), GFP_KERNEL);
340 	if (!dpcm)
341 		return -ENOMEM;
342 	substream->runtime->private_data = dpcm;
343 	init_timer(&dpcm->timer);
344 	dpcm->timer.data = (unsigned long) dpcm;
345 	dpcm->timer.function = dummy_systimer_callback;
346 	spin_lock_init(&dpcm->lock);
347 	dpcm->substream = substream;
348 	return 0;
349 }
350 
351 static void dummy_systimer_free(struct snd_pcm_substream *substream)
352 {
353 	kfree(substream->runtime->private_data);
354 }
355 
356 static struct dummy_timer_ops dummy_systimer_ops = {
357 	.create =	dummy_systimer_create,
358 	.free =		dummy_systimer_free,
359 	.prepare =	dummy_systimer_prepare,
360 	.start =	dummy_systimer_start,
361 	.stop =		dummy_systimer_stop,
362 	.pointer =	dummy_systimer_pointer,
363 };
364 
365 #ifdef CONFIG_HIGH_RES_TIMERS
366 /*
367  * hrtimer interface
368  */
369 
370 struct dummy_hrtimer_pcm {
371 	ktime_t base_time;
372 	ktime_t period_time;
373 	atomic_t running;
374 	struct hrtimer timer;
375 	struct tasklet_struct tasklet;
376 	struct snd_pcm_substream *substream;
377 };
378 
379 static void dummy_hrtimer_pcm_elapsed(unsigned long priv)
380 {
381 	struct dummy_hrtimer_pcm *dpcm = (struct dummy_hrtimer_pcm *)priv;
382 	if (atomic_read(&dpcm->running))
383 		snd_pcm_period_elapsed(dpcm->substream);
384 }
385 
386 static enum hrtimer_restart dummy_hrtimer_callback(struct hrtimer *timer)
387 {
388 	struct dummy_hrtimer_pcm *dpcm;
389 
390 	dpcm = container_of(timer, struct dummy_hrtimer_pcm, timer);
391 	if (!atomic_read(&dpcm->running))
392 		return HRTIMER_NORESTART;
393 	tasklet_schedule(&dpcm->tasklet);
394 	hrtimer_forward_now(timer, dpcm->period_time);
395 	return HRTIMER_RESTART;
396 }
397 
398 static int dummy_hrtimer_start(struct snd_pcm_substream *substream)
399 {
400 	struct dummy_hrtimer_pcm *dpcm = substream->runtime->private_data;
401 
402 	dpcm->base_time = hrtimer_cb_get_time(&dpcm->timer);
403 	hrtimer_start(&dpcm->timer, dpcm->period_time, HRTIMER_MODE_REL);
404 	atomic_set(&dpcm->running, 1);
405 	return 0;
406 }
407 
408 static int dummy_hrtimer_stop(struct snd_pcm_substream *substream)
409 {
410 	struct dummy_hrtimer_pcm *dpcm = substream->runtime->private_data;
411 
412 	atomic_set(&dpcm->running, 0);
413 	hrtimer_cancel(&dpcm->timer);
414 	return 0;
415 }
416 
417 static inline void dummy_hrtimer_sync(struct dummy_hrtimer_pcm *dpcm)
418 {
419 	tasklet_kill(&dpcm->tasklet);
420 }
421 
422 static snd_pcm_uframes_t
423 dummy_hrtimer_pointer(struct snd_pcm_substream *substream)
424 {
425 	struct snd_pcm_runtime *runtime = substream->runtime;
426 	struct dummy_hrtimer_pcm *dpcm = runtime->private_data;
427 	u64 delta;
428 	u32 pos;
429 
430 	delta = ktime_us_delta(hrtimer_cb_get_time(&dpcm->timer),
431 			       dpcm->base_time);
432 	delta = div_u64(delta * runtime->rate + 999999, 1000000);
433 	div_u64_rem(delta, runtime->buffer_size, &pos);
434 	return pos;
435 }
436 
437 static int dummy_hrtimer_prepare(struct snd_pcm_substream *substream)
438 {
439 	struct snd_pcm_runtime *runtime = substream->runtime;
440 	struct dummy_hrtimer_pcm *dpcm = runtime->private_data;
441 	unsigned int period, rate;
442 	long sec;
443 	unsigned long nsecs;
444 
445 	dummy_hrtimer_sync(dpcm);
446 	period = runtime->period_size;
447 	rate = runtime->rate;
448 	sec = period / rate;
449 	period %= rate;
450 	nsecs = div_u64((u64)period * 1000000000UL + rate - 1, rate);
451 	dpcm->period_time = ktime_set(sec, nsecs);
452 
453 	return 0;
454 }
455 
456 static int dummy_hrtimer_create(struct snd_pcm_substream *substream)
457 {
458 	struct dummy_hrtimer_pcm *dpcm;
459 
460 	dpcm = kzalloc(sizeof(*dpcm), GFP_KERNEL);
461 	if (!dpcm)
462 		return -ENOMEM;
463 	substream->runtime->private_data = dpcm;
464 	hrtimer_init(&dpcm->timer, CLOCK_MONOTONIC, HRTIMER_MODE_REL);
465 	dpcm->timer.function = dummy_hrtimer_callback;
466 	dpcm->substream = substream;
467 	atomic_set(&dpcm->running, 0);
468 	tasklet_init(&dpcm->tasklet, dummy_hrtimer_pcm_elapsed,
469 		     (unsigned long)dpcm);
470 	return 0;
471 }
472 
473 static void dummy_hrtimer_free(struct snd_pcm_substream *substream)
474 {
475 	struct dummy_hrtimer_pcm *dpcm = substream->runtime->private_data;
476 	dummy_hrtimer_sync(dpcm);
477 	kfree(dpcm);
478 }
479 
480 static struct dummy_timer_ops dummy_hrtimer_ops = {
481 	.create =	dummy_hrtimer_create,
482 	.free =		dummy_hrtimer_free,
483 	.prepare =	dummy_hrtimer_prepare,
484 	.start =	dummy_hrtimer_start,
485 	.stop =		dummy_hrtimer_stop,
486 	.pointer =	dummy_hrtimer_pointer,
487 };
488 
489 #endif /* CONFIG_HIGH_RES_TIMERS */
490 
491 /*
492  * PCM interface
493  */
494 
495 static int dummy_pcm_trigger(struct snd_pcm_substream *substream, int cmd)
496 {
497 	struct snd_dummy *dummy = snd_pcm_substream_chip(substream);
498 
499 	switch (cmd) {
500 	case SNDRV_PCM_TRIGGER_START:
501 	case SNDRV_PCM_TRIGGER_RESUME:
502 		return dummy->timer_ops->start(substream);
503 	case SNDRV_PCM_TRIGGER_STOP:
504 	case SNDRV_PCM_TRIGGER_SUSPEND:
505 		return dummy->timer_ops->stop(substream);
506 	}
507 	return -EINVAL;
508 }
509 
510 static int dummy_pcm_prepare(struct snd_pcm_substream *substream)
511 {
512 	struct snd_dummy *dummy = snd_pcm_substream_chip(substream);
513 
514 	return dummy->timer_ops->prepare(substream);
515 }
516 
517 static snd_pcm_uframes_t dummy_pcm_pointer(struct snd_pcm_substream *substream)
518 {
519 	struct snd_dummy *dummy = snd_pcm_substream_chip(substream);
520 
521 	return dummy->timer_ops->pointer(substream);
522 }
523 
524 static struct snd_pcm_hardware dummy_pcm_hardware = {
525 	.info =			(SNDRV_PCM_INFO_MMAP |
526 				 SNDRV_PCM_INFO_INTERLEAVED |
527 				 SNDRV_PCM_INFO_RESUME |
528 				 SNDRV_PCM_INFO_MMAP_VALID),
529 	.formats =		USE_FORMATS,
530 	.rates =		USE_RATE,
531 	.rate_min =		USE_RATE_MIN,
532 	.rate_max =		USE_RATE_MAX,
533 	.channels_min =		USE_CHANNELS_MIN,
534 	.channels_max =		USE_CHANNELS_MAX,
535 	.buffer_bytes_max =	MAX_BUFFER_SIZE,
536 	.period_bytes_min =	MIN_PERIOD_SIZE,
537 	.period_bytes_max =	MAX_PERIOD_SIZE,
538 	.periods_min =		USE_PERIODS_MIN,
539 	.periods_max =		USE_PERIODS_MAX,
540 	.fifo_size =		0,
541 };
542 
543 static int dummy_pcm_hw_params(struct snd_pcm_substream *substream,
544 			       struct snd_pcm_hw_params *hw_params)
545 {
546 	if (fake_buffer) {
547 		/* runtime->dma_bytes has to be set manually to allow mmap */
548 		substream->runtime->dma_bytes = params_buffer_bytes(hw_params);
549 		return 0;
550 	}
551 	return snd_pcm_lib_malloc_pages(substream,
552 					params_buffer_bytes(hw_params));
553 }
554 
555 static int dummy_pcm_hw_free(struct snd_pcm_substream *substream)
556 {
557 	if (fake_buffer)
558 		return 0;
559 	return snd_pcm_lib_free_pages(substream);
560 }
561 
562 static int dummy_pcm_open(struct snd_pcm_substream *substream)
563 {
564 	struct snd_dummy *dummy = snd_pcm_substream_chip(substream);
565 	struct dummy_model *model = dummy->model;
566 	struct snd_pcm_runtime *runtime = substream->runtime;
567 	int err;
568 
569 	dummy->timer_ops = &dummy_systimer_ops;
570 #ifdef CONFIG_HIGH_RES_TIMERS
571 	if (hrtimer)
572 		dummy->timer_ops = &dummy_hrtimer_ops;
573 #endif
574 
575 	err = dummy->timer_ops->create(substream);
576 	if (err < 0)
577 		return err;
578 
579 	runtime->hw = dummy->pcm_hw;
580 	if (substream->pcm->device & 1) {
581 		runtime->hw.info &= ~SNDRV_PCM_INFO_INTERLEAVED;
582 		runtime->hw.info |= SNDRV_PCM_INFO_NONINTERLEAVED;
583 	}
584 	if (substream->pcm->device & 2)
585 		runtime->hw.info &= ~(SNDRV_PCM_INFO_MMAP |
586 				      SNDRV_PCM_INFO_MMAP_VALID);
587 
588 	if (model == NULL)
589 		return 0;
590 
591 	if (substream->stream == SNDRV_PCM_STREAM_PLAYBACK) {
592 		if (model->playback_constraints)
593 			err = model->playback_constraints(substream->runtime);
594 	} else {
595 		if (model->capture_constraints)
596 			err = model->capture_constraints(substream->runtime);
597 	}
598 	if (err < 0) {
599 		dummy->timer_ops->free(substream);
600 		return err;
601 	}
602 	return 0;
603 }
604 
605 static int dummy_pcm_close(struct snd_pcm_substream *substream)
606 {
607 	struct snd_dummy *dummy = snd_pcm_substream_chip(substream);
608 	dummy->timer_ops->free(substream);
609 	return 0;
610 }
611 
612 /*
613  * dummy buffer handling
614  */
615 
616 static void *dummy_page[2];
617 
618 static void free_fake_buffer(void)
619 {
620 	if (fake_buffer) {
621 		int i;
622 		for (i = 0; i < 2; i++)
623 			if (dummy_page[i]) {
624 				free_page((unsigned long)dummy_page[i]);
625 				dummy_page[i] = NULL;
626 			}
627 	}
628 }
629 
630 static int alloc_fake_buffer(void)
631 {
632 	int i;
633 
634 	if (!fake_buffer)
635 		return 0;
636 	for (i = 0; i < 2; i++) {
637 		dummy_page[i] = (void *)get_zeroed_page(GFP_KERNEL);
638 		if (!dummy_page[i]) {
639 			free_fake_buffer();
640 			return -ENOMEM;
641 		}
642 	}
643 	return 0;
644 }
645 
646 static int dummy_pcm_copy(struct snd_pcm_substream *substream,
647 			  int channel, snd_pcm_uframes_t pos,
648 			  void __user *dst, snd_pcm_uframes_t count)
649 {
650 	return 0; /* do nothing */
651 }
652 
653 static int dummy_pcm_silence(struct snd_pcm_substream *substream,
654 			     int channel, snd_pcm_uframes_t pos,
655 			     snd_pcm_uframes_t count)
656 {
657 	return 0; /* do nothing */
658 }
659 
660 static struct page *dummy_pcm_page(struct snd_pcm_substream *substream,
661 				   unsigned long offset)
662 {
663 	return virt_to_page(dummy_page[substream->stream]); /* the same page */
664 }
665 
666 static struct snd_pcm_ops dummy_pcm_ops = {
667 	.open =		dummy_pcm_open,
668 	.close =	dummy_pcm_close,
669 	.ioctl =	snd_pcm_lib_ioctl,
670 	.hw_params =	dummy_pcm_hw_params,
671 	.hw_free =	dummy_pcm_hw_free,
672 	.prepare =	dummy_pcm_prepare,
673 	.trigger =	dummy_pcm_trigger,
674 	.pointer =	dummy_pcm_pointer,
675 };
676 
677 static struct snd_pcm_ops dummy_pcm_ops_no_buf = {
678 	.open =		dummy_pcm_open,
679 	.close =	dummy_pcm_close,
680 	.ioctl =	snd_pcm_lib_ioctl,
681 	.hw_params =	dummy_pcm_hw_params,
682 	.hw_free =	dummy_pcm_hw_free,
683 	.prepare =	dummy_pcm_prepare,
684 	.trigger =	dummy_pcm_trigger,
685 	.pointer =	dummy_pcm_pointer,
686 	.copy =		dummy_pcm_copy,
687 	.silence =	dummy_pcm_silence,
688 	.page =		dummy_pcm_page,
689 };
690 
691 static int snd_card_dummy_pcm(struct snd_dummy *dummy, int device,
692 			      int substreams)
693 {
694 	struct snd_pcm *pcm;
695 	struct snd_pcm_ops *ops;
696 	int err;
697 
698 	err = snd_pcm_new(dummy->card, "Dummy PCM", device,
699 			       substreams, substreams, &pcm);
700 	if (err < 0)
701 		return err;
702 	dummy->pcm = pcm;
703 	if (fake_buffer)
704 		ops = &dummy_pcm_ops_no_buf;
705 	else
706 		ops = &dummy_pcm_ops;
707 	snd_pcm_set_ops(pcm, SNDRV_PCM_STREAM_PLAYBACK, ops);
708 	snd_pcm_set_ops(pcm, SNDRV_PCM_STREAM_CAPTURE, ops);
709 	pcm->private_data = dummy;
710 	pcm->info_flags = 0;
711 	strcpy(pcm->name, "Dummy PCM");
712 	if (!fake_buffer) {
713 		snd_pcm_lib_preallocate_pages_for_all(pcm,
714 			SNDRV_DMA_TYPE_CONTINUOUS,
715 			snd_dma_continuous_data(GFP_KERNEL),
716 			0, 64*1024);
717 	}
718 	return 0;
719 }
720 
721 /*
722  * mixer interface
723  */
724 
725 #define DUMMY_VOLUME(xname, xindex, addr) \
726 { .iface = SNDRV_CTL_ELEM_IFACE_MIXER, \
727   .access = SNDRV_CTL_ELEM_ACCESS_READWRITE | SNDRV_CTL_ELEM_ACCESS_TLV_READ, \
728   .name = xname, .index = xindex, \
729   .info = snd_dummy_volume_info, \
730   .get = snd_dummy_volume_get, .put = snd_dummy_volume_put, \
731   .private_value = addr, \
732   .tlv = { .p = db_scale_dummy } }
733 
734 static int snd_dummy_volume_info(struct snd_kcontrol *kcontrol,
735 				 struct snd_ctl_elem_info *uinfo)
736 {
737 	uinfo->type = SNDRV_CTL_ELEM_TYPE_INTEGER;
738 	uinfo->count = 2;
739 	uinfo->value.integer.min = -50;
740 	uinfo->value.integer.max = 100;
741 	return 0;
742 }
743 
744 static int snd_dummy_volume_get(struct snd_kcontrol *kcontrol,
745 				struct snd_ctl_elem_value *ucontrol)
746 {
747 	struct snd_dummy *dummy = snd_kcontrol_chip(kcontrol);
748 	int addr = kcontrol->private_value;
749 
750 	spin_lock_irq(&dummy->mixer_lock);
751 	ucontrol->value.integer.value[0] = dummy->mixer_volume[addr][0];
752 	ucontrol->value.integer.value[1] = dummy->mixer_volume[addr][1];
753 	spin_unlock_irq(&dummy->mixer_lock);
754 	return 0;
755 }
756 
757 static int snd_dummy_volume_put(struct snd_kcontrol *kcontrol,
758 				struct snd_ctl_elem_value *ucontrol)
759 {
760 	struct snd_dummy *dummy = snd_kcontrol_chip(kcontrol);
761 	int change, addr = kcontrol->private_value;
762 	int left, right;
763 
764 	left = ucontrol->value.integer.value[0];
765 	if (left < -50)
766 		left = -50;
767 	if (left > 100)
768 		left = 100;
769 	right = ucontrol->value.integer.value[1];
770 	if (right < -50)
771 		right = -50;
772 	if (right > 100)
773 		right = 100;
774 	spin_lock_irq(&dummy->mixer_lock);
775 	change = dummy->mixer_volume[addr][0] != left ||
776 	         dummy->mixer_volume[addr][1] != right;
777 	dummy->mixer_volume[addr][0] = left;
778 	dummy->mixer_volume[addr][1] = right;
779 	spin_unlock_irq(&dummy->mixer_lock);
780 	return change;
781 }
782 
783 static const DECLARE_TLV_DB_SCALE(db_scale_dummy, -4500, 30, 0);
784 
785 #define DUMMY_CAPSRC(xname, xindex, addr) \
786 { .iface = SNDRV_CTL_ELEM_IFACE_MIXER, .name = xname, .index = xindex, \
787   .info = snd_dummy_capsrc_info, \
788   .get = snd_dummy_capsrc_get, .put = snd_dummy_capsrc_put, \
789   .private_value = addr }
790 
791 #define snd_dummy_capsrc_info	snd_ctl_boolean_stereo_info
792 
793 static int snd_dummy_capsrc_get(struct snd_kcontrol *kcontrol,
794 				struct snd_ctl_elem_value *ucontrol)
795 {
796 	struct snd_dummy *dummy = snd_kcontrol_chip(kcontrol);
797 	int addr = kcontrol->private_value;
798 
799 	spin_lock_irq(&dummy->mixer_lock);
800 	ucontrol->value.integer.value[0] = dummy->capture_source[addr][0];
801 	ucontrol->value.integer.value[1] = dummy->capture_source[addr][1];
802 	spin_unlock_irq(&dummy->mixer_lock);
803 	return 0;
804 }
805 
806 static int snd_dummy_capsrc_put(struct snd_kcontrol *kcontrol, struct snd_ctl_elem_value *ucontrol)
807 {
808 	struct snd_dummy *dummy = snd_kcontrol_chip(kcontrol);
809 	int change, addr = kcontrol->private_value;
810 	int left, right;
811 
812 	left = ucontrol->value.integer.value[0] & 1;
813 	right = ucontrol->value.integer.value[1] & 1;
814 	spin_lock_irq(&dummy->mixer_lock);
815 	change = dummy->capture_source[addr][0] != left &&
816 	         dummy->capture_source[addr][1] != right;
817 	dummy->capture_source[addr][0] = left;
818 	dummy->capture_source[addr][1] = right;
819 	spin_unlock_irq(&dummy->mixer_lock);
820 	return change;
821 }
822 
823 static int snd_dummy_iobox_info(struct snd_kcontrol *kcontrol,
824 				struct snd_ctl_elem_info *info)
825 {
826 	const char *const names[] = { "None", "CD Player" };
827 
828 	return snd_ctl_enum_info(info, 1, 2, names);
829 }
830 
831 static int snd_dummy_iobox_get(struct snd_kcontrol *kcontrol,
832 			       struct snd_ctl_elem_value *value)
833 {
834 	struct snd_dummy *dummy = snd_kcontrol_chip(kcontrol);
835 
836 	value->value.enumerated.item[0] = dummy->iobox;
837 	return 0;
838 }
839 
840 static int snd_dummy_iobox_put(struct snd_kcontrol *kcontrol,
841 			       struct snd_ctl_elem_value *value)
842 {
843 	struct snd_dummy *dummy = snd_kcontrol_chip(kcontrol);
844 	int changed;
845 
846 	if (value->value.enumerated.item[0] > 1)
847 		return -EINVAL;
848 
849 	changed = value->value.enumerated.item[0] != dummy->iobox;
850 	if (changed) {
851 		dummy->iobox = value->value.enumerated.item[0];
852 
853 		if (dummy->iobox) {
854 			dummy->cd_volume_ctl->vd[0].access &=
855 				~SNDRV_CTL_ELEM_ACCESS_INACTIVE;
856 			dummy->cd_switch_ctl->vd[0].access &=
857 				~SNDRV_CTL_ELEM_ACCESS_INACTIVE;
858 		} else {
859 			dummy->cd_volume_ctl->vd[0].access |=
860 				SNDRV_CTL_ELEM_ACCESS_INACTIVE;
861 			dummy->cd_switch_ctl->vd[0].access |=
862 				SNDRV_CTL_ELEM_ACCESS_INACTIVE;
863 		}
864 
865 		snd_ctl_notify(dummy->card, SNDRV_CTL_EVENT_MASK_INFO,
866 			       &dummy->cd_volume_ctl->id);
867 		snd_ctl_notify(dummy->card, SNDRV_CTL_EVENT_MASK_INFO,
868 			       &dummy->cd_switch_ctl->id);
869 	}
870 
871 	return changed;
872 }
873 
874 static struct snd_kcontrol_new snd_dummy_controls[] = {
875 DUMMY_VOLUME("Master Volume", 0, MIXER_ADDR_MASTER),
876 DUMMY_CAPSRC("Master Capture Switch", 0, MIXER_ADDR_MASTER),
877 DUMMY_VOLUME("Synth Volume", 0, MIXER_ADDR_SYNTH),
878 DUMMY_CAPSRC("Synth Capture Switch", 0, MIXER_ADDR_SYNTH),
879 DUMMY_VOLUME("Line Volume", 0, MIXER_ADDR_LINE),
880 DUMMY_CAPSRC("Line Capture Switch", 0, MIXER_ADDR_LINE),
881 DUMMY_VOLUME("Mic Volume", 0, MIXER_ADDR_MIC),
882 DUMMY_CAPSRC("Mic Capture Switch", 0, MIXER_ADDR_MIC),
883 DUMMY_VOLUME("CD Volume", 0, MIXER_ADDR_CD),
884 DUMMY_CAPSRC("CD Capture Switch", 0, MIXER_ADDR_CD),
885 {
886 	.iface = SNDRV_CTL_ELEM_IFACE_MIXER,
887 	.name  = "External I/O Box",
888 	.info  = snd_dummy_iobox_info,
889 	.get   = snd_dummy_iobox_get,
890 	.put   = snd_dummy_iobox_put,
891 },
892 };
893 
894 static int snd_card_dummy_new_mixer(struct snd_dummy *dummy)
895 {
896 	struct snd_card *card = dummy->card;
897 	struct snd_kcontrol *kcontrol;
898 	unsigned int idx;
899 	int err;
900 
901 	spin_lock_init(&dummy->mixer_lock);
902 	strcpy(card->mixername, "Dummy Mixer");
903 	dummy->iobox = 1;
904 
905 	for (idx = 0; idx < ARRAY_SIZE(snd_dummy_controls); idx++) {
906 		kcontrol = snd_ctl_new1(&snd_dummy_controls[idx], dummy);
907 		err = snd_ctl_add(card, kcontrol);
908 		if (err < 0)
909 			return err;
910 		if (!strcmp(kcontrol->id.name, "CD Volume"))
911 			dummy->cd_volume_ctl = kcontrol;
912 		else if (!strcmp(kcontrol->id.name, "CD Capture Switch"))
913 			dummy->cd_switch_ctl = kcontrol;
914 
915 	}
916 	return 0;
917 }
918 
919 #if defined(CONFIG_SND_DEBUG) && defined(CONFIG_PROC_FS)
920 /*
921  * proc interface
922  */
923 static void print_formats(struct snd_dummy *dummy,
924 			  struct snd_info_buffer *buffer)
925 {
926 	int i;
927 
928 	for (i = 0; i < SNDRV_PCM_FORMAT_LAST; i++) {
929 		if (dummy->pcm_hw.formats & (1ULL << i))
930 			snd_iprintf(buffer, " %s", snd_pcm_format_name(i));
931 	}
932 }
933 
934 static void print_rates(struct snd_dummy *dummy,
935 			struct snd_info_buffer *buffer)
936 {
937 	static int rates[] = {
938 		5512, 8000, 11025, 16000, 22050, 32000, 44100, 48000,
939 		64000, 88200, 96000, 176400, 192000,
940 	};
941 	int i;
942 
943 	if (dummy->pcm_hw.rates & SNDRV_PCM_RATE_CONTINUOUS)
944 		snd_iprintf(buffer, " continuous");
945 	if (dummy->pcm_hw.rates & SNDRV_PCM_RATE_KNOT)
946 		snd_iprintf(buffer, " knot");
947 	for (i = 0; i < ARRAY_SIZE(rates); i++)
948 		if (dummy->pcm_hw.rates & (1 << i))
949 			snd_iprintf(buffer, " %d", rates[i]);
950 }
951 
952 #define get_dummy_int_ptr(dummy, ofs) \
953 	(unsigned int *)((char *)&((dummy)->pcm_hw) + (ofs))
954 #define get_dummy_ll_ptr(dummy, ofs) \
955 	(unsigned long long *)((char *)&((dummy)->pcm_hw) + (ofs))
956 
957 struct dummy_hw_field {
958 	const char *name;
959 	const char *format;
960 	unsigned int offset;
961 	unsigned int size;
962 };
963 #define FIELD_ENTRY(item, fmt) {		   \
964 	.name = #item,				   \
965 	.format = fmt,				   \
966 	.offset = offsetof(struct snd_pcm_hardware, item), \
967 	.size = sizeof(dummy_pcm_hardware.item) }
968 
969 static struct dummy_hw_field fields[] = {
970 	FIELD_ENTRY(formats, "%#llx"),
971 	FIELD_ENTRY(rates, "%#x"),
972 	FIELD_ENTRY(rate_min, "%d"),
973 	FIELD_ENTRY(rate_max, "%d"),
974 	FIELD_ENTRY(channels_min, "%d"),
975 	FIELD_ENTRY(channels_max, "%d"),
976 	FIELD_ENTRY(buffer_bytes_max, "%ld"),
977 	FIELD_ENTRY(period_bytes_min, "%ld"),
978 	FIELD_ENTRY(period_bytes_max, "%ld"),
979 	FIELD_ENTRY(periods_min, "%d"),
980 	FIELD_ENTRY(periods_max, "%d"),
981 };
982 
983 static void dummy_proc_read(struct snd_info_entry *entry,
984 			    struct snd_info_buffer *buffer)
985 {
986 	struct snd_dummy *dummy = entry->private_data;
987 	int i;
988 
989 	for (i = 0; i < ARRAY_SIZE(fields); i++) {
990 		snd_iprintf(buffer, "%s ", fields[i].name);
991 		if (fields[i].size == sizeof(int))
992 			snd_iprintf(buffer, fields[i].format,
993 				*get_dummy_int_ptr(dummy, fields[i].offset));
994 		else
995 			snd_iprintf(buffer, fields[i].format,
996 				*get_dummy_ll_ptr(dummy, fields[i].offset));
997 		if (!strcmp(fields[i].name, "formats"))
998 			print_formats(dummy, buffer);
999 		else if (!strcmp(fields[i].name, "rates"))
1000 			print_rates(dummy, buffer);
1001 		snd_iprintf(buffer, "\n");
1002 	}
1003 }
1004 
1005 static void dummy_proc_write(struct snd_info_entry *entry,
1006 			     struct snd_info_buffer *buffer)
1007 {
1008 	struct snd_dummy *dummy = entry->private_data;
1009 	char line[64];
1010 
1011 	while (!snd_info_get_line(buffer, line, sizeof(line))) {
1012 		char item[20];
1013 		const char *ptr;
1014 		unsigned long long val;
1015 		int i;
1016 
1017 		ptr = snd_info_get_str(item, line, sizeof(item));
1018 		for (i = 0; i < ARRAY_SIZE(fields); i++) {
1019 			if (!strcmp(item, fields[i].name))
1020 				break;
1021 		}
1022 		if (i >= ARRAY_SIZE(fields))
1023 			continue;
1024 		snd_info_get_str(item, ptr, sizeof(item));
1025 		if (kstrtoull(item, 0, &val))
1026 			continue;
1027 		if (fields[i].size == sizeof(int))
1028 			*get_dummy_int_ptr(dummy, fields[i].offset) = val;
1029 		else
1030 			*get_dummy_ll_ptr(dummy, fields[i].offset) = val;
1031 	}
1032 }
1033 
1034 static void dummy_proc_init(struct snd_dummy *chip)
1035 {
1036 	struct snd_info_entry *entry;
1037 
1038 	if (!snd_card_proc_new(chip->card, "dummy_pcm", &entry)) {
1039 		snd_info_set_text_ops(entry, chip, dummy_proc_read);
1040 		entry->c.text.write = dummy_proc_write;
1041 		entry->mode |= S_IWUSR;
1042 		entry->private_data = chip;
1043 	}
1044 }
1045 #else
1046 #define dummy_proc_init(x)
1047 #endif /* CONFIG_SND_DEBUG && CONFIG_PROC_FS */
1048 
1049 static int snd_dummy_probe(struct platform_device *devptr)
1050 {
1051 	struct snd_card *card;
1052 	struct snd_dummy *dummy;
1053 	struct dummy_model *m = NULL, **mdl;
1054 	int idx, err;
1055 	int dev = devptr->id;
1056 
1057 	err = snd_card_new(&devptr->dev, index[dev], id[dev], THIS_MODULE,
1058 			   sizeof(struct snd_dummy), &card);
1059 	if (err < 0)
1060 		return err;
1061 	dummy = card->private_data;
1062 	dummy->card = card;
1063 	for (mdl = dummy_models; *mdl && model[dev]; mdl++) {
1064 		if (strcmp(model[dev], (*mdl)->name) == 0) {
1065 			printk(KERN_INFO
1066 				"snd-dummy: Using model '%s' for card %i\n",
1067 				(*mdl)->name, card->number);
1068 			m = dummy->model = *mdl;
1069 			break;
1070 		}
1071 	}
1072 	for (idx = 0; idx < MAX_PCM_DEVICES && idx < pcm_devs[dev]; idx++) {
1073 		if (pcm_substreams[dev] < 1)
1074 			pcm_substreams[dev] = 1;
1075 		if (pcm_substreams[dev] > MAX_PCM_SUBSTREAMS)
1076 			pcm_substreams[dev] = MAX_PCM_SUBSTREAMS;
1077 		err = snd_card_dummy_pcm(dummy, idx, pcm_substreams[dev]);
1078 		if (err < 0)
1079 			goto __nodev;
1080 	}
1081 
1082 	dummy->pcm_hw = dummy_pcm_hardware;
1083 	if (m) {
1084 		if (m->formats)
1085 			dummy->pcm_hw.formats = m->formats;
1086 		if (m->buffer_bytes_max)
1087 			dummy->pcm_hw.buffer_bytes_max = m->buffer_bytes_max;
1088 		if (m->period_bytes_min)
1089 			dummy->pcm_hw.period_bytes_min = m->period_bytes_min;
1090 		if (m->period_bytes_max)
1091 			dummy->pcm_hw.period_bytes_max = m->period_bytes_max;
1092 		if (m->periods_min)
1093 			dummy->pcm_hw.periods_min = m->periods_min;
1094 		if (m->periods_max)
1095 			dummy->pcm_hw.periods_max = m->periods_max;
1096 		if (m->rates)
1097 			dummy->pcm_hw.rates = m->rates;
1098 		if (m->rate_min)
1099 			dummy->pcm_hw.rate_min = m->rate_min;
1100 		if (m->rate_max)
1101 			dummy->pcm_hw.rate_max = m->rate_max;
1102 		if (m->channels_min)
1103 			dummy->pcm_hw.channels_min = m->channels_min;
1104 		if (m->channels_max)
1105 			dummy->pcm_hw.channels_max = m->channels_max;
1106 	}
1107 
1108 	err = snd_card_dummy_new_mixer(dummy);
1109 	if (err < 0)
1110 		goto __nodev;
1111 	strcpy(card->driver, "Dummy");
1112 	strcpy(card->shortname, "Dummy");
1113 	sprintf(card->longname, "Dummy %i", dev + 1);
1114 
1115 	dummy_proc_init(dummy);
1116 
1117 	err = snd_card_register(card);
1118 	if (err == 0) {
1119 		platform_set_drvdata(devptr, card);
1120 		return 0;
1121 	}
1122       __nodev:
1123 	snd_card_free(card);
1124 	return err;
1125 }
1126 
1127 static int snd_dummy_remove(struct platform_device *devptr)
1128 {
1129 	snd_card_free(platform_get_drvdata(devptr));
1130 	return 0;
1131 }
1132 
1133 #ifdef CONFIG_PM_SLEEP
1134 static int snd_dummy_suspend(struct device *pdev)
1135 {
1136 	struct snd_card *card = dev_get_drvdata(pdev);
1137 	struct snd_dummy *dummy = card->private_data;
1138 
1139 	snd_power_change_state(card, SNDRV_CTL_POWER_D3hot);
1140 	snd_pcm_suspend_all(dummy->pcm);
1141 	return 0;
1142 }
1143 
1144 static int snd_dummy_resume(struct device *pdev)
1145 {
1146 	struct snd_card *card = dev_get_drvdata(pdev);
1147 
1148 	snd_power_change_state(card, SNDRV_CTL_POWER_D0);
1149 	return 0;
1150 }
1151 
1152 static SIMPLE_DEV_PM_OPS(snd_dummy_pm, snd_dummy_suspend, snd_dummy_resume);
1153 #define SND_DUMMY_PM_OPS	&snd_dummy_pm
1154 #else
1155 #define SND_DUMMY_PM_OPS	NULL
1156 #endif
1157 
1158 #define SND_DUMMY_DRIVER	"snd_dummy"
1159 
1160 static struct platform_driver snd_dummy_driver = {
1161 	.probe		= snd_dummy_probe,
1162 	.remove		= snd_dummy_remove,
1163 	.driver		= {
1164 		.name	= SND_DUMMY_DRIVER,
1165 		.pm	= SND_DUMMY_PM_OPS,
1166 	},
1167 };
1168 
1169 static void snd_dummy_unregister_all(void)
1170 {
1171 	int i;
1172 
1173 	for (i = 0; i < ARRAY_SIZE(devices); ++i)
1174 		platform_device_unregister(devices[i]);
1175 	platform_driver_unregister(&snd_dummy_driver);
1176 	free_fake_buffer();
1177 }
1178 
1179 static int __init alsa_card_dummy_init(void)
1180 {
1181 	int i, cards, err;
1182 
1183 	err = platform_driver_register(&snd_dummy_driver);
1184 	if (err < 0)
1185 		return err;
1186 
1187 	err = alloc_fake_buffer();
1188 	if (err < 0) {
1189 		platform_driver_unregister(&snd_dummy_driver);
1190 		return err;
1191 	}
1192 
1193 	cards = 0;
1194 	for (i = 0; i < SNDRV_CARDS; i++) {
1195 		struct platform_device *device;
1196 		if (! enable[i])
1197 			continue;
1198 		device = platform_device_register_simple(SND_DUMMY_DRIVER,
1199 							 i, NULL, 0);
1200 		if (IS_ERR(device))
1201 			continue;
1202 		if (!platform_get_drvdata(device)) {
1203 			platform_device_unregister(device);
1204 			continue;
1205 		}
1206 		devices[i] = device;
1207 		cards++;
1208 	}
1209 	if (!cards) {
1210 #ifdef MODULE
1211 		printk(KERN_ERR "Dummy soundcard not found or device busy\n");
1212 #endif
1213 		snd_dummy_unregister_all();
1214 		return -ENODEV;
1215 	}
1216 	return 0;
1217 }
1218 
1219 static void __exit alsa_card_dummy_exit(void)
1220 {
1221 	snd_dummy_unregister_all();
1222 }
1223 
1224 module_init(alsa_card_dummy_init)
1225 module_exit(alsa_card_dummy_exit)
1226