xref: /linux/sound/drivers/dummy.c (revision 37cb8e1f8e10c6e9bd2a1b95cdda0620a21b0551)
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 tasklet_struct tasklet;
379 	struct snd_pcm_substream *substream;
380 };
381 
382 static void dummy_hrtimer_pcm_elapsed(unsigned long priv)
383 {
384 	struct dummy_hrtimer_pcm *dpcm = (struct dummy_hrtimer_pcm *)priv;
385 	if (atomic_read(&dpcm->running))
386 		snd_pcm_period_elapsed(dpcm->substream);
387 }
388 
389 static enum hrtimer_restart dummy_hrtimer_callback(struct hrtimer *timer)
390 {
391 	struct dummy_hrtimer_pcm *dpcm;
392 
393 	dpcm = container_of(timer, struct dummy_hrtimer_pcm, timer);
394 	if (!atomic_read(&dpcm->running))
395 		return HRTIMER_NORESTART;
396 	tasklet_schedule(&dpcm->tasklet);
397 	hrtimer_forward_now(timer, dpcm->period_time);
398 	return HRTIMER_RESTART;
399 }
400 
401 static int dummy_hrtimer_start(struct snd_pcm_substream *substream)
402 {
403 	struct dummy_hrtimer_pcm *dpcm = substream->runtime->private_data;
404 
405 	dpcm->base_time = hrtimer_cb_get_time(&dpcm->timer);
406 	hrtimer_start(&dpcm->timer, dpcm->period_time, HRTIMER_MODE_REL);
407 	atomic_set(&dpcm->running, 1);
408 	return 0;
409 }
410 
411 static int dummy_hrtimer_stop(struct snd_pcm_substream *substream)
412 {
413 	struct dummy_hrtimer_pcm *dpcm = substream->runtime->private_data;
414 
415 	atomic_set(&dpcm->running, 0);
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 	tasklet_kill(&dpcm->tasklet);
424 }
425 
426 static snd_pcm_uframes_t
427 dummy_hrtimer_pointer(struct snd_pcm_substream *substream)
428 {
429 	struct snd_pcm_runtime *runtime = substream->runtime;
430 	struct dummy_hrtimer_pcm *dpcm = runtime->private_data;
431 	u64 delta;
432 	u32 pos;
433 
434 	delta = ktime_us_delta(hrtimer_cb_get_time(&dpcm->timer),
435 			       dpcm->base_time);
436 	delta = div_u64(delta * runtime->rate + 999999, 1000000);
437 	div_u64_rem(delta, runtime->buffer_size, &pos);
438 	return pos;
439 }
440 
441 static int dummy_hrtimer_prepare(struct snd_pcm_substream *substream)
442 {
443 	struct snd_pcm_runtime *runtime = substream->runtime;
444 	struct dummy_hrtimer_pcm *dpcm = runtime->private_data;
445 	unsigned int period, rate;
446 	long sec;
447 	unsigned long nsecs;
448 
449 	dummy_hrtimer_sync(dpcm);
450 	period = runtime->period_size;
451 	rate = runtime->rate;
452 	sec = period / rate;
453 	period %= rate;
454 	nsecs = div_u64((u64)period * 1000000000UL + rate - 1, rate);
455 	dpcm->period_time = ktime_set(sec, nsecs);
456 
457 	return 0;
458 }
459 
460 static int dummy_hrtimer_create(struct snd_pcm_substream *substream)
461 {
462 	struct dummy_hrtimer_pcm *dpcm;
463 
464 	dpcm = kzalloc(sizeof(*dpcm), GFP_KERNEL);
465 	if (!dpcm)
466 		return -ENOMEM;
467 	substream->runtime->private_data = dpcm;
468 	hrtimer_init(&dpcm->timer, CLOCK_MONOTONIC, HRTIMER_MODE_REL);
469 	dpcm->timer.function = dummy_hrtimer_callback;
470 	dpcm->substream = substream;
471 	atomic_set(&dpcm->running, 0);
472 	tasklet_init(&dpcm->tasklet, dummy_hrtimer_pcm_elapsed,
473 		     (unsigned long)dpcm);
474 	return 0;
475 }
476 
477 static void dummy_hrtimer_free(struct snd_pcm_substream *substream)
478 {
479 	struct dummy_hrtimer_pcm *dpcm = substream->runtime->private_data;
480 	dummy_hrtimer_sync(dpcm);
481 	kfree(dpcm);
482 }
483 
484 static const struct dummy_timer_ops dummy_hrtimer_ops = {
485 	.create =	dummy_hrtimer_create,
486 	.free =		dummy_hrtimer_free,
487 	.prepare =	dummy_hrtimer_prepare,
488 	.start =	dummy_hrtimer_start,
489 	.stop =		dummy_hrtimer_stop,
490 	.pointer =	dummy_hrtimer_pointer,
491 };
492 
493 #endif /* CONFIG_HIGH_RES_TIMERS */
494 
495 /*
496  * PCM interface
497  */
498 
499 static int dummy_pcm_trigger(struct snd_pcm_substream *substream, int cmd)
500 {
501 	switch (cmd) {
502 	case SNDRV_PCM_TRIGGER_START:
503 	case SNDRV_PCM_TRIGGER_RESUME:
504 		return get_dummy_ops(substream)->start(substream);
505 	case SNDRV_PCM_TRIGGER_STOP:
506 	case SNDRV_PCM_TRIGGER_SUSPEND:
507 		return get_dummy_ops(substream)->stop(substream);
508 	}
509 	return -EINVAL;
510 }
511 
512 static int dummy_pcm_prepare(struct snd_pcm_substream *substream)
513 {
514 	return get_dummy_ops(substream)->prepare(substream);
515 }
516 
517 static snd_pcm_uframes_t dummy_pcm_pointer(struct snd_pcm_substream *substream)
518 {
519 	return get_dummy_ops(substream)->pointer(substream);
520 }
521 
522 static const struct snd_pcm_hardware dummy_pcm_hardware = {
523 	.info =			(SNDRV_PCM_INFO_MMAP |
524 				 SNDRV_PCM_INFO_INTERLEAVED |
525 				 SNDRV_PCM_INFO_RESUME |
526 				 SNDRV_PCM_INFO_MMAP_VALID),
527 	.formats =		USE_FORMATS,
528 	.rates =		USE_RATE,
529 	.rate_min =		USE_RATE_MIN,
530 	.rate_max =		USE_RATE_MAX,
531 	.channels_min =		USE_CHANNELS_MIN,
532 	.channels_max =		USE_CHANNELS_MAX,
533 	.buffer_bytes_max =	MAX_BUFFER_SIZE,
534 	.period_bytes_min =	MIN_PERIOD_SIZE,
535 	.period_bytes_max =	MAX_PERIOD_SIZE,
536 	.periods_min =		USE_PERIODS_MIN,
537 	.periods_max =		USE_PERIODS_MAX,
538 	.fifo_size =		0,
539 };
540 
541 static int dummy_pcm_hw_params(struct snd_pcm_substream *substream,
542 			       struct snd_pcm_hw_params *hw_params)
543 {
544 	if (fake_buffer) {
545 		/* runtime->dma_bytes has to be set manually to allow mmap */
546 		substream->runtime->dma_bytes = params_buffer_bytes(hw_params);
547 		return 0;
548 	}
549 	return snd_pcm_lib_malloc_pages(substream,
550 					params_buffer_bytes(hw_params));
551 }
552 
553 static int dummy_pcm_hw_free(struct snd_pcm_substream *substream)
554 {
555 	if (fake_buffer)
556 		return 0;
557 	return snd_pcm_lib_free_pages(substream);
558 }
559 
560 static int dummy_pcm_open(struct snd_pcm_substream *substream)
561 {
562 	struct snd_dummy *dummy = snd_pcm_substream_chip(substream);
563 	struct dummy_model *model = dummy->model;
564 	struct snd_pcm_runtime *runtime = substream->runtime;
565 	const struct dummy_timer_ops *ops;
566 	int err;
567 
568 	ops = &dummy_systimer_ops;
569 #ifdef CONFIG_HIGH_RES_TIMERS
570 	if (hrtimer)
571 		ops = &dummy_hrtimer_ops;
572 #endif
573 
574 	err = ops->create(substream);
575 	if (err < 0)
576 		return err;
577 	get_dummy_ops(substream) = ops;
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 		get_dummy_ops(substream)->free(substream);
600 		return err;
601 	}
602 	return 0;
603 }
604 
605 static int dummy_pcm_close(struct snd_pcm_substream *substream)
606 {
607 	get_dummy_ops(substream)->free(substream);
608 	return 0;
609 }
610 
611 /*
612  * dummy buffer handling
613  */
614 
615 static void *dummy_page[2];
616 
617 static void free_fake_buffer(void)
618 {
619 	if (fake_buffer) {
620 		int i;
621 		for (i = 0; i < 2; i++)
622 			if (dummy_page[i]) {
623 				free_page((unsigned long)dummy_page[i]);
624 				dummy_page[i] = NULL;
625 			}
626 	}
627 }
628 
629 static int alloc_fake_buffer(void)
630 {
631 	int i;
632 
633 	if (!fake_buffer)
634 		return 0;
635 	for (i = 0; i < 2; i++) {
636 		dummy_page[i] = (void *)get_zeroed_page(GFP_KERNEL);
637 		if (!dummy_page[i]) {
638 			free_fake_buffer();
639 			return -ENOMEM;
640 		}
641 	}
642 	return 0;
643 }
644 
645 static int dummy_pcm_copy(struct snd_pcm_substream *substream,
646 			  int channel, unsigned long pos,
647 			  void __user *dst, unsigned long bytes)
648 {
649 	return 0; /* do nothing */
650 }
651 
652 static int dummy_pcm_copy_kernel(struct snd_pcm_substream *substream,
653 				 int channel, unsigned long pos,
654 				 void *dst, unsigned long bytes)
655 {
656 	return 0; /* do nothing */
657 }
658 
659 static int dummy_pcm_silence(struct snd_pcm_substream *substream,
660 			     int channel, unsigned long pos,
661 			     unsigned long bytes)
662 {
663 	return 0; /* do nothing */
664 }
665 
666 static struct page *dummy_pcm_page(struct snd_pcm_substream *substream,
667 				   unsigned long offset)
668 {
669 	return virt_to_page(dummy_page[substream->stream]); /* the same page */
670 }
671 
672 static struct snd_pcm_ops dummy_pcm_ops = {
673 	.open =		dummy_pcm_open,
674 	.close =	dummy_pcm_close,
675 	.ioctl =	snd_pcm_lib_ioctl,
676 	.hw_params =	dummy_pcm_hw_params,
677 	.hw_free =	dummy_pcm_hw_free,
678 	.prepare =	dummy_pcm_prepare,
679 	.trigger =	dummy_pcm_trigger,
680 	.pointer =	dummy_pcm_pointer,
681 };
682 
683 static struct snd_pcm_ops dummy_pcm_ops_no_buf = {
684 	.open =		dummy_pcm_open,
685 	.close =	dummy_pcm_close,
686 	.ioctl =	snd_pcm_lib_ioctl,
687 	.hw_params =	dummy_pcm_hw_params,
688 	.hw_free =	dummy_pcm_hw_free,
689 	.prepare =	dummy_pcm_prepare,
690 	.trigger =	dummy_pcm_trigger,
691 	.pointer =	dummy_pcm_pointer,
692 	.copy_user =	dummy_pcm_copy,
693 	.copy_kernel =	dummy_pcm_copy_kernel,
694 	.fill_silence =	dummy_pcm_silence,
695 	.page =		dummy_pcm_page,
696 };
697 
698 static int snd_card_dummy_pcm(struct snd_dummy *dummy, int device,
699 			      int substreams)
700 {
701 	struct snd_pcm *pcm;
702 	struct snd_pcm_ops *ops;
703 	int err;
704 
705 	err = snd_pcm_new(dummy->card, "Dummy PCM", device,
706 			       substreams, substreams, &pcm);
707 	if (err < 0)
708 		return err;
709 	dummy->pcm = pcm;
710 	if (fake_buffer)
711 		ops = &dummy_pcm_ops_no_buf;
712 	else
713 		ops = &dummy_pcm_ops;
714 	snd_pcm_set_ops(pcm, SNDRV_PCM_STREAM_PLAYBACK, ops);
715 	snd_pcm_set_ops(pcm, SNDRV_PCM_STREAM_CAPTURE, ops);
716 	pcm->private_data = dummy;
717 	pcm->info_flags = 0;
718 	strcpy(pcm->name, "Dummy PCM");
719 	if (!fake_buffer) {
720 		snd_pcm_lib_preallocate_pages_for_all(pcm,
721 			SNDRV_DMA_TYPE_CONTINUOUS,
722 			snd_dma_continuous_data(GFP_KERNEL),
723 			0, 64*1024);
724 	}
725 	return 0;
726 }
727 
728 /*
729  * mixer interface
730  */
731 
732 #define DUMMY_VOLUME(xname, xindex, addr) \
733 { .iface = SNDRV_CTL_ELEM_IFACE_MIXER, \
734   .access = SNDRV_CTL_ELEM_ACCESS_READWRITE | SNDRV_CTL_ELEM_ACCESS_TLV_READ, \
735   .name = xname, .index = xindex, \
736   .info = snd_dummy_volume_info, \
737   .get = snd_dummy_volume_get, .put = snd_dummy_volume_put, \
738   .private_value = addr, \
739   .tlv = { .p = db_scale_dummy } }
740 
741 static int snd_dummy_volume_info(struct snd_kcontrol *kcontrol,
742 				 struct snd_ctl_elem_info *uinfo)
743 {
744 	uinfo->type = SNDRV_CTL_ELEM_TYPE_INTEGER;
745 	uinfo->count = 2;
746 	uinfo->value.integer.min = -50;
747 	uinfo->value.integer.max = 100;
748 	return 0;
749 }
750 
751 static int snd_dummy_volume_get(struct snd_kcontrol *kcontrol,
752 				struct snd_ctl_elem_value *ucontrol)
753 {
754 	struct snd_dummy *dummy = snd_kcontrol_chip(kcontrol);
755 	int addr = kcontrol->private_value;
756 
757 	spin_lock_irq(&dummy->mixer_lock);
758 	ucontrol->value.integer.value[0] = dummy->mixer_volume[addr][0];
759 	ucontrol->value.integer.value[1] = dummy->mixer_volume[addr][1];
760 	spin_unlock_irq(&dummy->mixer_lock);
761 	return 0;
762 }
763 
764 static int snd_dummy_volume_put(struct snd_kcontrol *kcontrol,
765 				struct snd_ctl_elem_value *ucontrol)
766 {
767 	struct snd_dummy *dummy = snd_kcontrol_chip(kcontrol);
768 	int change, addr = kcontrol->private_value;
769 	int left, right;
770 
771 	left = ucontrol->value.integer.value[0];
772 	if (left < -50)
773 		left = -50;
774 	if (left > 100)
775 		left = 100;
776 	right = ucontrol->value.integer.value[1];
777 	if (right < -50)
778 		right = -50;
779 	if (right > 100)
780 		right = 100;
781 	spin_lock_irq(&dummy->mixer_lock);
782 	change = dummy->mixer_volume[addr][0] != left ||
783 	         dummy->mixer_volume[addr][1] != right;
784 	dummy->mixer_volume[addr][0] = left;
785 	dummy->mixer_volume[addr][1] = right;
786 	spin_unlock_irq(&dummy->mixer_lock);
787 	return change;
788 }
789 
790 static const DECLARE_TLV_DB_SCALE(db_scale_dummy, -4500, 30, 0);
791 
792 #define DUMMY_CAPSRC(xname, xindex, addr) \
793 { .iface = SNDRV_CTL_ELEM_IFACE_MIXER, .name = xname, .index = xindex, \
794   .info = snd_dummy_capsrc_info, \
795   .get = snd_dummy_capsrc_get, .put = snd_dummy_capsrc_put, \
796   .private_value = addr }
797 
798 #define snd_dummy_capsrc_info	snd_ctl_boolean_stereo_info
799 
800 static int snd_dummy_capsrc_get(struct snd_kcontrol *kcontrol,
801 				struct snd_ctl_elem_value *ucontrol)
802 {
803 	struct snd_dummy *dummy = snd_kcontrol_chip(kcontrol);
804 	int addr = kcontrol->private_value;
805 
806 	spin_lock_irq(&dummy->mixer_lock);
807 	ucontrol->value.integer.value[0] = dummy->capture_source[addr][0];
808 	ucontrol->value.integer.value[1] = dummy->capture_source[addr][1];
809 	spin_unlock_irq(&dummy->mixer_lock);
810 	return 0;
811 }
812 
813 static int snd_dummy_capsrc_put(struct snd_kcontrol *kcontrol, struct snd_ctl_elem_value *ucontrol)
814 {
815 	struct snd_dummy *dummy = snd_kcontrol_chip(kcontrol);
816 	int change, addr = kcontrol->private_value;
817 	int left, right;
818 
819 	left = ucontrol->value.integer.value[0] & 1;
820 	right = ucontrol->value.integer.value[1] & 1;
821 	spin_lock_irq(&dummy->mixer_lock);
822 	change = dummy->capture_source[addr][0] != left &&
823 	         dummy->capture_source[addr][1] != right;
824 	dummy->capture_source[addr][0] = left;
825 	dummy->capture_source[addr][1] = right;
826 	spin_unlock_irq(&dummy->mixer_lock);
827 	return change;
828 }
829 
830 static int snd_dummy_iobox_info(struct snd_kcontrol *kcontrol,
831 				struct snd_ctl_elem_info *info)
832 {
833 	const char *const names[] = { "None", "CD Player" };
834 
835 	return snd_ctl_enum_info(info, 1, 2, names);
836 }
837 
838 static int snd_dummy_iobox_get(struct snd_kcontrol *kcontrol,
839 			       struct snd_ctl_elem_value *value)
840 {
841 	struct snd_dummy *dummy = snd_kcontrol_chip(kcontrol);
842 
843 	value->value.enumerated.item[0] = dummy->iobox;
844 	return 0;
845 }
846 
847 static int snd_dummy_iobox_put(struct snd_kcontrol *kcontrol,
848 			       struct snd_ctl_elem_value *value)
849 {
850 	struct snd_dummy *dummy = snd_kcontrol_chip(kcontrol);
851 	int changed;
852 
853 	if (value->value.enumerated.item[0] > 1)
854 		return -EINVAL;
855 
856 	changed = value->value.enumerated.item[0] != dummy->iobox;
857 	if (changed) {
858 		dummy->iobox = value->value.enumerated.item[0];
859 
860 		if (dummy->iobox) {
861 			dummy->cd_volume_ctl->vd[0].access &=
862 				~SNDRV_CTL_ELEM_ACCESS_INACTIVE;
863 			dummy->cd_switch_ctl->vd[0].access &=
864 				~SNDRV_CTL_ELEM_ACCESS_INACTIVE;
865 		} else {
866 			dummy->cd_volume_ctl->vd[0].access |=
867 				SNDRV_CTL_ELEM_ACCESS_INACTIVE;
868 			dummy->cd_switch_ctl->vd[0].access |=
869 				SNDRV_CTL_ELEM_ACCESS_INACTIVE;
870 		}
871 
872 		snd_ctl_notify(dummy->card, SNDRV_CTL_EVENT_MASK_INFO,
873 			       &dummy->cd_volume_ctl->id);
874 		snd_ctl_notify(dummy->card, SNDRV_CTL_EVENT_MASK_INFO,
875 			       &dummy->cd_switch_ctl->id);
876 	}
877 
878 	return changed;
879 }
880 
881 static struct snd_kcontrol_new snd_dummy_controls[] = {
882 DUMMY_VOLUME("Master Volume", 0, MIXER_ADDR_MASTER),
883 DUMMY_CAPSRC("Master Capture Switch", 0, MIXER_ADDR_MASTER),
884 DUMMY_VOLUME("Synth Volume", 0, MIXER_ADDR_SYNTH),
885 DUMMY_CAPSRC("Synth Capture Switch", 0, MIXER_ADDR_SYNTH),
886 DUMMY_VOLUME("Line Volume", 0, MIXER_ADDR_LINE),
887 DUMMY_CAPSRC("Line Capture Switch", 0, MIXER_ADDR_LINE),
888 DUMMY_VOLUME("Mic Volume", 0, MIXER_ADDR_MIC),
889 DUMMY_CAPSRC("Mic Capture Switch", 0, MIXER_ADDR_MIC),
890 DUMMY_VOLUME("CD Volume", 0, MIXER_ADDR_CD),
891 DUMMY_CAPSRC("CD Capture Switch", 0, MIXER_ADDR_CD),
892 {
893 	.iface = SNDRV_CTL_ELEM_IFACE_MIXER,
894 	.name  = "External I/O Box",
895 	.info  = snd_dummy_iobox_info,
896 	.get   = snd_dummy_iobox_get,
897 	.put   = snd_dummy_iobox_put,
898 },
899 };
900 
901 static int snd_card_dummy_new_mixer(struct snd_dummy *dummy)
902 {
903 	struct snd_card *card = dummy->card;
904 	struct snd_kcontrol *kcontrol;
905 	unsigned int idx;
906 	int err;
907 
908 	spin_lock_init(&dummy->mixer_lock);
909 	strcpy(card->mixername, "Dummy Mixer");
910 	dummy->iobox = 1;
911 
912 	for (idx = 0; idx < ARRAY_SIZE(snd_dummy_controls); idx++) {
913 		kcontrol = snd_ctl_new1(&snd_dummy_controls[idx], dummy);
914 		err = snd_ctl_add(card, kcontrol);
915 		if (err < 0)
916 			return err;
917 		if (!strcmp(kcontrol->id.name, "CD Volume"))
918 			dummy->cd_volume_ctl = kcontrol;
919 		else if (!strcmp(kcontrol->id.name, "CD Capture Switch"))
920 			dummy->cd_switch_ctl = kcontrol;
921 
922 	}
923 	return 0;
924 }
925 
926 #if defined(CONFIG_SND_DEBUG) && defined(CONFIG_SND_PROC_FS)
927 /*
928  * proc interface
929  */
930 static void print_formats(struct snd_dummy *dummy,
931 			  struct snd_info_buffer *buffer)
932 {
933 	int i;
934 
935 	for (i = 0; i < SNDRV_PCM_FORMAT_LAST; i++) {
936 		if (dummy->pcm_hw.formats & (1ULL << i))
937 			snd_iprintf(buffer, " %s", snd_pcm_format_name(i));
938 	}
939 }
940 
941 static void print_rates(struct snd_dummy *dummy,
942 			struct snd_info_buffer *buffer)
943 {
944 	static int rates[] = {
945 		5512, 8000, 11025, 16000, 22050, 32000, 44100, 48000,
946 		64000, 88200, 96000, 176400, 192000,
947 	};
948 	int i;
949 
950 	if (dummy->pcm_hw.rates & SNDRV_PCM_RATE_CONTINUOUS)
951 		snd_iprintf(buffer, " continuous");
952 	if (dummy->pcm_hw.rates & SNDRV_PCM_RATE_KNOT)
953 		snd_iprintf(buffer, " knot");
954 	for (i = 0; i < ARRAY_SIZE(rates); i++)
955 		if (dummy->pcm_hw.rates & (1 << i))
956 			snd_iprintf(buffer, " %d", rates[i]);
957 }
958 
959 #define get_dummy_int_ptr(dummy, ofs) \
960 	(unsigned int *)((char *)&((dummy)->pcm_hw) + (ofs))
961 #define get_dummy_ll_ptr(dummy, ofs) \
962 	(unsigned long long *)((char *)&((dummy)->pcm_hw) + (ofs))
963 
964 struct dummy_hw_field {
965 	const char *name;
966 	const char *format;
967 	unsigned int offset;
968 	unsigned int size;
969 };
970 #define FIELD_ENTRY(item, fmt) {		   \
971 	.name = #item,				   \
972 	.format = fmt,				   \
973 	.offset = offsetof(struct snd_pcm_hardware, item), \
974 	.size = sizeof(dummy_pcm_hardware.item) }
975 
976 static struct dummy_hw_field fields[] = {
977 	FIELD_ENTRY(formats, "%#llx"),
978 	FIELD_ENTRY(rates, "%#x"),
979 	FIELD_ENTRY(rate_min, "%d"),
980 	FIELD_ENTRY(rate_max, "%d"),
981 	FIELD_ENTRY(channels_min, "%d"),
982 	FIELD_ENTRY(channels_max, "%d"),
983 	FIELD_ENTRY(buffer_bytes_max, "%ld"),
984 	FIELD_ENTRY(period_bytes_min, "%ld"),
985 	FIELD_ENTRY(period_bytes_max, "%ld"),
986 	FIELD_ENTRY(periods_min, "%d"),
987 	FIELD_ENTRY(periods_max, "%d"),
988 };
989 
990 static void dummy_proc_read(struct snd_info_entry *entry,
991 			    struct snd_info_buffer *buffer)
992 {
993 	struct snd_dummy *dummy = entry->private_data;
994 	int i;
995 
996 	for (i = 0; i < ARRAY_SIZE(fields); i++) {
997 		snd_iprintf(buffer, "%s ", fields[i].name);
998 		if (fields[i].size == sizeof(int))
999 			snd_iprintf(buffer, fields[i].format,
1000 				*get_dummy_int_ptr(dummy, fields[i].offset));
1001 		else
1002 			snd_iprintf(buffer, fields[i].format,
1003 				*get_dummy_ll_ptr(dummy, fields[i].offset));
1004 		if (!strcmp(fields[i].name, "formats"))
1005 			print_formats(dummy, buffer);
1006 		else if (!strcmp(fields[i].name, "rates"))
1007 			print_rates(dummy, buffer);
1008 		snd_iprintf(buffer, "\n");
1009 	}
1010 }
1011 
1012 static void dummy_proc_write(struct snd_info_entry *entry,
1013 			     struct snd_info_buffer *buffer)
1014 {
1015 	struct snd_dummy *dummy = entry->private_data;
1016 	char line[64];
1017 
1018 	while (!snd_info_get_line(buffer, line, sizeof(line))) {
1019 		char item[20];
1020 		const char *ptr;
1021 		unsigned long long val;
1022 		int i;
1023 
1024 		ptr = snd_info_get_str(item, line, sizeof(item));
1025 		for (i = 0; i < ARRAY_SIZE(fields); i++) {
1026 			if (!strcmp(item, fields[i].name))
1027 				break;
1028 		}
1029 		if (i >= ARRAY_SIZE(fields))
1030 			continue;
1031 		snd_info_get_str(item, ptr, sizeof(item));
1032 		if (kstrtoull(item, 0, &val))
1033 			continue;
1034 		if (fields[i].size == sizeof(int))
1035 			*get_dummy_int_ptr(dummy, fields[i].offset) = val;
1036 		else
1037 			*get_dummy_ll_ptr(dummy, fields[i].offset) = val;
1038 	}
1039 }
1040 
1041 static void dummy_proc_init(struct snd_dummy *chip)
1042 {
1043 	struct snd_info_entry *entry;
1044 
1045 	if (!snd_card_proc_new(chip->card, "dummy_pcm", &entry)) {
1046 		snd_info_set_text_ops(entry, chip, dummy_proc_read);
1047 		entry->c.text.write = dummy_proc_write;
1048 		entry->mode |= S_IWUSR;
1049 		entry->private_data = chip;
1050 	}
1051 }
1052 #else
1053 #define dummy_proc_init(x)
1054 #endif /* CONFIG_SND_DEBUG && CONFIG_SND_PROC_FS */
1055 
1056 static int snd_dummy_probe(struct platform_device *devptr)
1057 {
1058 	struct snd_card *card;
1059 	struct snd_dummy *dummy;
1060 	struct dummy_model *m = NULL, **mdl;
1061 	int idx, err;
1062 	int dev = devptr->id;
1063 
1064 	err = snd_card_new(&devptr->dev, index[dev], id[dev], THIS_MODULE,
1065 			   sizeof(struct snd_dummy), &card);
1066 	if (err < 0)
1067 		return err;
1068 	dummy = card->private_data;
1069 	dummy->card = card;
1070 	for (mdl = dummy_models; *mdl && model[dev]; mdl++) {
1071 		if (strcmp(model[dev], (*mdl)->name) == 0) {
1072 			printk(KERN_INFO
1073 				"snd-dummy: Using model '%s' for card %i\n",
1074 				(*mdl)->name, card->number);
1075 			m = dummy->model = *mdl;
1076 			break;
1077 		}
1078 	}
1079 	for (idx = 0; idx < MAX_PCM_DEVICES && idx < pcm_devs[dev]; idx++) {
1080 		if (pcm_substreams[dev] < 1)
1081 			pcm_substreams[dev] = 1;
1082 		if (pcm_substreams[dev] > MAX_PCM_SUBSTREAMS)
1083 			pcm_substreams[dev] = MAX_PCM_SUBSTREAMS;
1084 		err = snd_card_dummy_pcm(dummy, idx, pcm_substreams[dev]);
1085 		if (err < 0)
1086 			goto __nodev;
1087 	}
1088 
1089 	dummy->pcm_hw = dummy_pcm_hardware;
1090 	if (m) {
1091 		if (m->formats)
1092 			dummy->pcm_hw.formats = m->formats;
1093 		if (m->buffer_bytes_max)
1094 			dummy->pcm_hw.buffer_bytes_max = m->buffer_bytes_max;
1095 		if (m->period_bytes_min)
1096 			dummy->pcm_hw.period_bytes_min = m->period_bytes_min;
1097 		if (m->period_bytes_max)
1098 			dummy->pcm_hw.period_bytes_max = m->period_bytes_max;
1099 		if (m->periods_min)
1100 			dummy->pcm_hw.periods_min = m->periods_min;
1101 		if (m->periods_max)
1102 			dummy->pcm_hw.periods_max = m->periods_max;
1103 		if (m->rates)
1104 			dummy->pcm_hw.rates = m->rates;
1105 		if (m->rate_min)
1106 			dummy->pcm_hw.rate_min = m->rate_min;
1107 		if (m->rate_max)
1108 			dummy->pcm_hw.rate_max = m->rate_max;
1109 		if (m->channels_min)
1110 			dummy->pcm_hw.channels_min = m->channels_min;
1111 		if (m->channels_max)
1112 			dummy->pcm_hw.channels_max = m->channels_max;
1113 	}
1114 
1115 	err = snd_card_dummy_new_mixer(dummy);
1116 	if (err < 0)
1117 		goto __nodev;
1118 	strcpy(card->driver, "Dummy");
1119 	strcpy(card->shortname, "Dummy");
1120 	sprintf(card->longname, "Dummy %i", dev + 1);
1121 
1122 	dummy_proc_init(dummy);
1123 
1124 	err = snd_card_register(card);
1125 	if (err == 0) {
1126 		platform_set_drvdata(devptr, card);
1127 		return 0;
1128 	}
1129       __nodev:
1130 	snd_card_free(card);
1131 	return err;
1132 }
1133 
1134 static int snd_dummy_remove(struct platform_device *devptr)
1135 {
1136 	snd_card_free(platform_get_drvdata(devptr));
1137 	return 0;
1138 }
1139 
1140 #ifdef CONFIG_PM_SLEEP
1141 static int snd_dummy_suspend(struct device *pdev)
1142 {
1143 	struct snd_card *card = dev_get_drvdata(pdev);
1144 	struct snd_dummy *dummy = card->private_data;
1145 
1146 	snd_power_change_state(card, SNDRV_CTL_POWER_D3hot);
1147 	snd_pcm_suspend_all(dummy->pcm);
1148 	return 0;
1149 }
1150 
1151 static int snd_dummy_resume(struct device *pdev)
1152 {
1153 	struct snd_card *card = dev_get_drvdata(pdev);
1154 
1155 	snd_power_change_state(card, SNDRV_CTL_POWER_D0);
1156 	return 0;
1157 }
1158 
1159 static SIMPLE_DEV_PM_OPS(snd_dummy_pm, snd_dummy_suspend, snd_dummy_resume);
1160 #define SND_DUMMY_PM_OPS	&snd_dummy_pm
1161 #else
1162 #define SND_DUMMY_PM_OPS	NULL
1163 #endif
1164 
1165 #define SND_DUMMY_DRIVER	"snd_dummy"
1166 
1167 static struct platform_driver snd_dummy_driver = {
1168 	.probe		= snd_dummy_probe,
1169 	.remove		= snd_dummy_remove,
1170 	.driver		= {
1171 		.name	= SND_DUMMY_DRIVER,
1172 		.pm	= SND_DUMMY_PM_OPS,
1173 	},
1174 };
1175 
1176 static void snd_dummy_unregister_all(void)
1177 {
1178 	int i;
1179 
1180 	for (i = 0; i < ARRAY_SIZE(devices); ++i)
1181 		platform_device_unregister(devices[i]);
1182 	platform_driver_unregister(&snd_dummy_driver);
1183 	free_fake_buffer();
1184 }
1185 
1186 static int __init alsa_card_dummy_init(void)
1187 {
1188 	int i, cards, err;
1189 
1190 	err = platform_driver_register(&snd_dummy_driver);
1191 	if (err < 0)
1192 		return err;
1193 
1194 	err = alloc_fake_buffer();
1195 	if (err < 0) {
1196 		platform_driver_unregister(&snd_dummy_driver);
1197 		return err;
1198 	}
1199 
1200 	cards = 0;
1201 	for (i = 0; i < SNDRV_CARDS; i++) {
1202 		struct platform_device *device;
1203 		if (! enable[i])
1204 			continue;
1205 		device = platform_device_register_simple(SND_DUMMY_DRIVER,
1206 							 i, NULL, 0);
1207 		if (IS_ERR(device))
1208 			continue;
1209 		if (!platform_get_drvdata(device)) {
1210 			platform_device_unregister(device);
1211 			continue;
1212 		}
1213 		devices[i] = device;
1214 		cards++;
1215 	}
1216 	if (!cards) {
1217 #ifdef MODULE
1218 		printk(KERN_ERR "Dummy soundcard not found or device busy\n");
1219 #endif
1220 		snd_dummy_unregister_all();
1221 		return -ENODEV;
1222 	}
1223 	return 0;
1224 }
1225 
1226 static void __exit alsa_card_dummy_exit(void)
1227 {
1228 	snd_dummy_unregister_all();
1229 }
1230 
1231 module_init(alsa_card_dummy_init)
1232 module_exit(alsa_card_dummy_exit)
1233