xref: /openbmc/linux/sound/drivers/dummy.c (revision 9cfc5c90)
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 static struct dummy_model model_emu10k1 = {
160 	.name = "emu10k1",
161 	.playback_constraints = emu10k1_playback_constraints,
162 	.buffer_bytes_max = 128 * 1024,
163 };
164 
165 static 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 static 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 static 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 static 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 static 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 static 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 	mod_timer(&dpcm->timer, jiffies +
249 		(dpcm->frac_period_rest + dpcm->rate - 1) / dpcm->rate);
250 }
251 
252 static void dummy_systimer_update(struct dummy_systimer_pcm *dpcm)
253 {
254 	unsigned long delta;
255 
256 	delta = jiffies - dpcm->base_time;
257 	if (!delta)
258 		return;
259 	dpcm->base_time += delta;
260 	delta *= dpcm->rate;
261 	dpcm->frac_pos += delta;
262 	while (dpcm->frac_pos >= dpcm->frac_buffer_size)
263 		dpcm->frac_pos -= dpcm->frac_buffer_size;
264 	while (dpcm->frac_period_rest <= delta) {
265 		dpcm->elapsed++;
266 		dpcm->frac_period_rest += dpcm->frac_period_size;
267 	}
268 	dpcm->frac_period_rest -= delta;
269 }
270 
271 static int dummy_systimer_start(struct snd_pcm_substream *substream)
272 {
273 	struct dummy_systimer_pcm *dpcm = substream->runtime->private_data;
274 	spin_lock(&dpcm->lock);
275 	dpcm->base_time = jiffies;
276 	dummy_systimer_rearm(dpcm);
277 	spin_unlock(&dpcm->lock);
278 	return 0;
279 }
280 
281 static int dummy_systimer_stop(struct snd_pcm_substream *substream)
282 {
283 	struct dummy_systimer_pcm *dpcm = substream->runtime->private_data;
284 	spin_lock(&dpcm->lock);
285 	del_timer(&dpcm->timer);
286 	spin_unlock(&dpcm->lock);
287 	return 0;
288 }
289 
290 static int dummy_systimer_prepare(struct snd_pcm_substream *substream)
291 {
292 	struct snd_pcm_runtime *runtime = substream->runtime;
293 	struct dummy_systimer_pcm *dpcm = runtime->private_data;
294 
295 	dpcm->frac_pos = 0;
296 	dpcm->rate = runtime->rate;
297 	dpcm->frac_buffer_size = runtime->buffer_size * HZ;
298 	dpcm->frac_period_size = runtime->period_size * HZ;
299 	dpcm->frac_period_rest = dpcm->frac_period_size;
300 	dpcm->elapsed = 0;
301 
302 	return 0;
303 }
304 
305 static void dummy_systimer_callback(unsigned long data)
306 {
307 	struct dummy_systimer_pcm *dpcm = (struct dummy_systimer_pcm *)data;
308 	unsigned long flags;
309 	int elapsed = 0;
310 
311 	spin_lock_irqsave(&dpcm->lock, flags);
312 	dummy_systimer_update(dpcm);
313 	dummy_systimer_rearm(dpcm);
314 	elapsed = dpcm->elapsed;
315 	dpcm->elapsed = 0;
316 	spin_unlock_irqrestore(&dpcm->lock, flags);
317 	if (elapsed)
318 		snd_pcm_period_elapsed(dpcm->substream);
319 }
320 
321 static snd_pcm_uframes_t
322 dummy_systimer_pointer(struct snd_pcm_substream *substream)
323 {
324 	struct dummy_systimer_pcm *dpcm = substream->runtime->private_data;
325 	snd_pcm_uframes_t pos;
326 
327 	spin_lock(&dpcm->lock);
328 	dummy_systimer_update(dpcm);
329 	pos = dpcm->frac_pos / HZ;
330 	spin_unlock(&dpcm->lock);
331 	return pos;
332 }
333 
334 static int dummy_systimer_create(struct snd_pcm_substream *substream)
335 {
336 	struct dummy_systimer_pcm *dpcm;
337 
338 	dpcm = kzalloc(sizeof(*dpcm), GFP_KERNEL);
339 	if (!dpcm)
340 		return -ENOMEM;
341 	substream->runtime->private_data = dpcm;
342 	setup_timer(&dpcm->timer, dummy_systimer_callback,
343 			(unsigned long) dpcm);
344 	spin_lock_init(&dpcm->lock);
345 	dpcm->substream = substream;
346 	return 0;
347 }
348 
349 static void dummy_systimer_free(struct snd_pcm_substream *substream)
350 {
351 	kfree(substream->runtime->private_data);
352 }
353 
354 static struct dummy_timer_ops dummy_systimer_ops = {
355 	.create =	dummy_systimer_create,
356 	.free =		dummy_systimer_free,
357 	.prepare =	dummy_systimer_prepare,
358 	.start =	dummy_systimer_start,
359 	.stop =		dummy_systimer_stop,
360 	.pointer =	dummy_systimer_pointer,
361 };
362 
363 #ifdef CONFIG_HIGH_RES_TIMERS
364 /*
365  * hrtimer interface
366  */
367 
368 struct dummy_hrtimer_pcm {
369 	ktime_t base_time;
370 	ktime_t period_time;
371 	atomic_t running;
372 	struct hrtimer timer;
373 	struct tasklet_struct tasklet;
374 	struct snd_pcm_substream *substream;
375 };
376 
377 static void dummy_hrtimer_pcm_elapsed(unsigned long priv)
378 {
379 	struct dummy_hrtimer_pcm *dpcm = (struct dummy_hrtimer_pcm *)priv;
380 	if (atomic_read(&dpcm->running))
381 		snd_pcm_period_elapsed(dpcm->substream);
382 }
383 
384 static enum hrtimer_restart dummy_hrtimer_callback(struct hrtimer *timer)
385 {
386 	struct dummy_hrtimer_pcm *dpcm;
387 
388 	dpcm = container_of(timer, struct dummy_hrtimer_pcm, timer);
389 	if (!atomic_read(&dpcm->running))
390 		return HRTIMER_NORESTART;
391 	tasklet_schedule(&dpcm->tasklet);
392 	hrtimer_forward_now(timer, dpcm->period_time);
393 	return HRTIMER_RESTART;
394 }
395 
396 static int dummy_hrtimer_start(struct snd_pcm_substream *substream)
397 {
398 	struct dummy_hrtimer_pcm *dpcm = substream->runtime->private_data;
399 
400 	dpcm->base_time = hrtimer_cb_get_time(&dpcm->timer);
401 	hrtimer_start(&dpcm->timer, dpcm->period_time, HRTIMER_MODE_REL);
402 	atomic_set(&dpcm->running, 1);
403 	return 0;
404 }
405 
406 static int dummy_hrtimer_stop(struct snd_pcm_substream *substream)
407 {
408 	struct dummy_hrtimer_pcm *dpcm = substream->runtime->private_data;
409 
410 	atomic_set(&dpcm->running, 0);
411 	hrtimer_cancel(&dpcm->timer);
412 	return 0;
413 }
414 
415 static inline void dummy_hrtimer_sync(struct dummy_hrtimer_pcm *dpcm)
416 {
417 	tasklet_kill(&dpcm->tasklet);
418 }
419 
420 static snd_pcm_uframes_t
421 dummy_hrtimer_pointer(struct snd_pcm_substream *substream)
422 {
423 	struct snd_pcm_runtime *runtime = substream->runtime;
424 	struct dummy_hrtimer_pcm *dpcm = runtime->private_data;
425 	u64 delta;
426 	u32 pos;
427 
428 	delta = ktime_us_delta(hrtimer_cb_get_time(&dpcm->timer),
429 			       dpcm->base_time);
430 	delta = div_u64(delta * runtime->rate + 999999, 1000000);
431 	div_u64_rem(delta, runtime->buffer_size, &pos);
432 	return pos;
433 }
434 
435 static int dummy_hrtimer_prepare(struct snd_pcm_substream *substream)
436 {
437 	struct snd_pcm_runtime *runtime = substream->runtime;
438 	struct dummy_hrtimer_pcm *dpcm = runtime->private_data;
439 	unsigned int period, rate;
440 	long sec;
441 	unsigned long nsecs;
442 
443 	dummy_hrtimer_sync(dpcm);
444 	period = runtime->period_size;
445 	rate = runtime->rate;
446 	sec = period / rate;
447 	period %= rate;
448 	nsecs = div_u64((u64)period * 1000000000UL + rate - 1, rate);
449 	dpcm->period_time = ktime_set(sec, nsecs);
450 
451 	return 0;
452 }
453 
454 static int dummy_hrtimer_create(struct snd_pcm_substream *substream)
455 {
456 	struct dummy_hrtimer_pcm *dpcm;
457 
458 	dpcm = kzalloc(sizeof(*dpcm), GFP_KERNEL);
459 	if (!dpcm)
460 		return -ENOMEM;
461 	substream->runtime->private_data = dpcm;
462 	hrtimer_init(&dpcm->timer, CLOCK_MONOTONIC, HRTIMER_MODE_REL);
463 	dpcm->timer.function = dummy_hrtimer_callback;
464 	dpcm->substream = substream;
465 	atomic_set(&dpcm->running, 0);
466 	tasklet_init(&dpcm->tasklet, dummy_hrtimer_pcm_elapsed,
467 		     (unsigned long)dpcm);
468 	return 0;
469 }
470 
471 static void dummy_hrtimer_free(struct snd_pcm_substream *substream)
472 {
473 	struct dummy_hrtimer_pcm *dpcm = substream->runtime->private_data;
474 	dummy_hrtimer_sync(dpcm);
475 	kfree(dpcm);
476 }
477 
478 static struct dummy_timer_ops dummy_hrtimer_ops = {
479 	.create =	dummy_hrtimer_create,
480 	.free =		dummy_hrtimer_free,
481 	.prepare =	dummy_hrtimer_prepare,
482 	.start =	dummy_hrtimer_start,
483 	.stop =		dummy_hrtimer_stop,
484 	.pointer =	dummy_hrtimer_pointer,
485 };
486 
487 #endif /* CONFIG_HIGH_RES_TIMERS */
488 
489 /*
490  * PCM interface
491  */
492 
493 static int dummy_pcm_trigger(struct snd_pcm_substream *substream, int cmd)
494 {
495 	struct snd_dummy *dummy = snd_pcm_substream_chip(substream);
496 
497 	switch (cmd) {
498 	case SNDRV_PCM_TRIGGER_START:
499 	case SNDRV_PCM_TRIGGER_RESUME:
500 		return dummy->timer_ops->start(substream);
501 	case SNDRV_PCM_TRIGGER_STOP:
502 	case SNDRV_PCM_TRIGGER_SUSPEND:
503 		return dummy->timer_ops->stop(substream);
504 	}
505 	return -EINVAL;
506 }
507 
508 static int dummy_pcm_prepare(struct snd_pcm_substream *substream)
509 {
510 	struct snd_dummy *dummy = snd_pcm_substream_chip(substream);
511 
512 	return dummy->timer_ops->prepare(substream);
513 }
514 
515 static snd_pcm_uframes_t dummy_pcm_pointer(struct snd_pcm_substream *substream)
516 {
517 	struct snd_dummy *dummy = snd_pcm_substream_chip(substream);
518 
519 	return dummy->timer_ops->pointer(substream);
520 }
521 
522 static 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 	int err;
566 
567 	dummy->timer_ops = &dummy_systimer_ops;
568 #ifdef CONFIG_HIGH_RES_TIMERS
569 	if (hrtimer)
570 		dummy->timer_ops = &dummy_hrtimer_ops;
571 #endif
572 
573 	err = dummy->timer_ops->create(substream);
574 	if (err < 0)
575 		return err;
576 
577 	runtime->hw = dummy->pcm_hw;
578 	if (substream->pcm->device & 1) {
579 		runtime->hw.info &= ~SNDRV_PCM_INFO_INTERLEAVED;
580 		runtime->hw.info |= SNDRV_PCM_INFO_NONINTERLEAVED;
581 	}
582 	if (substream->pcm->device & 2)
583 		runtime->hw.info &= ~(SNDRV_PCM_INFO_MMAP |
584 				      SNDRV_PCM_INFO_MMAP_VALID);
585 
586 	if (model == NULL)
587 		return 0;
588 
589 	if (substream->stream == SNDRV_PCM_STREAM_PLAYBACK) {
590 		if (model->playback_constraints)
591 			err = model->playback_constraints(substream->runtime);
592 	} else {
593 		if (model->capture_constraints)
594 			err = model->capture_constraints(substream->runtime);
595 	}
596 	if (err < 0) {
597 		dummy->timer_ops->free(substream);
598 		return err;
599 	}
600 	return 0;
601 }
602 
603 static int dummy_pcm_close(struct snd_pcm_substream *substream)
604 {
605 	struct snd_dummy *dummy = snd_pcm_substream_chip(substream);
606 	dummy->timer_ops->free(substream);
607 	return 0;
608 }
609 
610 /*
611  * dummy buffer handling
612  */
613 
614 static void *dummy_page[2];
615 
616 static void free_fake_buffer(void)
617 {
618 	if (fake_buffer) {
619 		int i;
620 		for (i = 0; i < 2; i++)
621 			if (dummy_page[i]) {
622 				free_page((unsigned long)dummy_page[i]);
623 				dummy_page[i] = NULL;
624 			}
625 	}
626 }
627 
628 static int alloc_fake_buffer(void)
629 {
630 	int i;
631 
632 	if (!fake_buffer)
633 		return 0;
634 	for (i = 0; i < 2; i++) {
635 		dummy_page[i] = (void *)get_zeroed_page(GFP_KERNEL);
636 		if (!dummy_page[i]) {
637 			free_fake_buffer();
638 			return -ENOMEM;
639 		}
640 	}
641 	return 0;
642 }
643 
644 static int dummy_pcm_copy(struct snd_pcm_substream *substream,
645 			  int channel, snd_pcm_uframes_t pos,
646 			  void __user *dst, snd_pcm_uframes_t count)
647 {
648 	return 0; /* do nothing */
649 }
650 
651 static int dummy_pcm_silence(struct snd_pcm_substream *substream,
652 			     int channel, snd_pcm_uframes_t pos,
653 			     snd_pcm_uframes_t count)
654 {
655 	return 0; /* do nothing */
656 }
657 
658 static struct page *dummy_pcm_page(struct snd_pcm_substream *substream,
659 				   unsigned long offset)
660 {
661 	return virt_to_page(dummy_page[substream->stream]); /* the same page */
662 }
663 
664 static struct snd_pcm_ops dummy_pcm_ops = {
665 	.open =		dummy_pcm_open,
666 	.close =	dummy_pcm_close,
667 	.ioctl =	snd_pcm_lib_ioctl,
668 	.hw_params =	dummy_pcm_hw_params,
669 	.hw_free =	dummy_pcm_hw_free,
670 	.prepare =	dummy_pcm_prepare,
671 	.trigger =	dummy_pcm_trigger,
672 	.pointer =	dummy_pcm_pointer,
673 };
674 
675 static struct snd_pcm_ops dummy_pcm_ops_no_buf = {
676 	.open =		dummy_pcm_open,
677 	.close =	dummy_pcm_close,
678 	.ioctl =	snd_pcm_lib_ioctl,
679 	.hw_params =	dummy_pcm_hw_params,
680 	.hw_free =	dummy_pcm_hw_free,
681 	.prepare =	dummy_pcm_prepare,
682 	.trigger =	dummy_pcm_trigger,
683 	.pointer =	dummy_pcm_pointer,
684 	.copy =		dummy_pcm_copy,
685 	.silence =	dummy_pcm_silence,
686 	.page =		dummy_pcm_page,
687 };
688 
689 static int snd_card_dummy_pcm(struct snd_dummy *dummy, int device,
690 			      int substreams)
691 {
692 	struct snd_pcm *pcm;
693 	struct snd_pcm_ops *ops;
694 	int err;
695 
696 	err = snd_pcm_new(dummy->card, "Dummy PCM", device,
697 			       substreams, substreams, &pcm);
698 	if (err < 0)
699 		return err;
700 	dummy->pcm = pcm;
701 	if (fake_buffer)
702 		ops = &dummy_pcm_ops_no_buf;
703 	else
704 		ops = &dummy_pcm_ops;
705 	snd_pcm_set_ops(pcm, SNDRV_PCM_STREAM_PLAYBACK, ops);
706 	snd_pcm_set_ops(pcm, SNDRV_PCM_STREAM_CAPTURE, ops);
707 	pcm->private_data = dummy;
708 	pcm->info_flags = 0;
709 	strcpy(pcm->name, "Dummy PCM");
710 	if (!fake_buffer) {
711 		snd_pcm_lib_preallocate_pages_for_all(pcm,
712 			SNDRV_DMA_TYPE_CONTINUOUS,
713 			snd_dma_continuous_data(GFP_KERNEL),
714 			0, 64*1024);
715 	}
716 	return 0;
717 }
718 
719 /*
720  * mixer interface
721  */
722 
723 #define DUMMY_VOLUME(xname, xindex, addr) \
724 { .iface = SNDRV_CTL_ELEM_IFACE_MIXER, \
725   .access = SNDRV_CTL_ELEM_ACCESS_READWRITE | SNDRV_CTL_ELEM_ACCESS_TLV_READ, \
726   .name = xname, .index = xindex, \
727   .info = snd_dummy_volume_info, \
728   .get = snd_dummy_volume_get, .put = snd_dummy_volume_put, \
729   .private_value = addr, \
730   .tlv = { .p = db_scale_dummy } }
731 
732 static int snd_dummy_volume_info(struct snd_kcontrol *kcontrol,
733 				 struct snd_ctl_elem_info *uinfo)
734 {
735 	uinfo->type = SNDRV_CTL_ELEM_TYPE_INTEGER;
736 	uinfo->count = 2;
737 	uinfo->value.integer.min = -50;
738 	uinfo->value.integer.max = 100;
739 	return 0;
740 }
741 
742 static int snd_dummy_volume_get(struct snd_kcontrol *kcontrol,
743 				struct snd_ctl_elem_value *ucontrol)
744 {
745 	struct snd_dummy *dummy = snd_kcontrol_chip(kcontrol);
746 	int addr = kcontrol->private_value;
747 
748 	spin_lock_irq(&dummy->mixer_lock);
749 	ucontrol->value.integer.value[0] = dummy->mixer_volume[addr][0];
750 	ucontrol->value.integer.value[1] = dummy->mixer_volume[addr][1];
751 	spin_unlock_irq(&dummy->mixer_lock);
752 	return 0;
753 }
754 
755 static int snd_dummy_volume_put(struct snd_kcontrol *kcontrol,
756 				struct snd_ctl_elem_value *ucontrol)
757 {
758 	struct snd_dummy *dummy = snd_kcontrol_chip(kcontrol);
759 	int change, addr = kcontrol->private_value;
760 	int left, right;
761 
762 	left = ucontrol->value.integer.value[0];
763 	if (left < -50)
764 		left = -50;
765 	if (left > 100)
766 		left = 100;
767 	right = ucontrol->value.integer.value[1];
768 	if (right < -50)
769 		right = -50;
770 	if (right > 100)
771 		right = 100;
772 	spin_lock_irq(&dummy->mixer_lock);
773 	change = dummy->mixer_volume[addr][0] != left ||
774 	         dummy->mixer_volume[addr][1] != right;
775 	dummy->mixer_volume[addr][0] = left;
776 	dummy->mixer_volume[addr][1] = right;
777 	spin_unlock_irq(&dummy->mixer_lock);
778 	return change;
779 }
780 
781 static const DECLARE_TLV_DB_SCALE(db_scale_dummy, -4500, 30, 0);
782 
783 #define DUMMY_CAPSRC(xname, xindex, addr) \
784 { .iface = SNDRV_CTL_ELEM_IFACE_MIXER, .name = xname, .index = xindex, \
785   .info = snd_dummy_capsrc_info, \
786   .get = snd_dummy_capsrc_get, .put = snd_dummy_capsrc_put, \
787   .private_value = addr }
788 
789 #define snd_dummy_capsrc_info	snd_ctl_boolean_stereo_info
790 
791 static int snd_dummy_capsrc_get(struct snd_kcontrol *kcontrol,
792 				struct snd_ctl_elem_value *ucontrol)
793 {
794 	struct snd_dummy *dummy = snd_kcontrol_chip(kcontrol);
795 	int addr = kcontrol->private_value;
796 
797 	spin_lock_irq(&dummy->mixer_lock);
798 	ucontrol->value.integer.value[0] = dummy->capture_source[addr][0];
799 	ucontrol->value.integer.value[1] = dummy->capture_source[addr][1];
800 	spin_unlock_irq(&dummy->mixer_lock);
801 	return 0;
802 }
803 
804 static int snd_dummy_capsrc_put(struct snd_kcontrol *kcontrol, struct snd_ctl_elem_value *ucontrol)
805 {
806 	struct snd_dummy *dummy = snd_kcontrol_chip(kcontrol);
807 	int change, addr = kcontrol->private_value;
808 	int left, right;
809 
810 	left = ucontrol->value.integer.value[0] & 1;
811 	right = ucontrol->value.integer.value[1] & 1;
812 	spin_lock_irq(&dummy->mixer_lock);
813 	change = dummy->capture_source[addr][0] != left &&
814 	         dummy->capture_source[addr][1] != right;
815 	dummy->capture_source[addr][0] = left;
816 	dummy->capture_source[addr][1] = right;
817 	spin_unlock_irq(&dummy->mixer_lock);
818 	return change;
819 }
820 
821 static int snd_dummy_iobox_info(struct snd_kcontrol *kcontrol,
822 				struct snd_ctl_elem_info *info)
823 {
824 	const char *const names[] = { "None", "CD Player" };
825 
826 	return snd_ctl_enum_info(info, 1, 2, names);
827 }
828 
829 static int snd_dummy_iobox_get(struct snd_kcontrol *kcontrol,
830 			       struct snd_ctl_elem_value *value)
831 {
832 	struct snd_dummy *dummy = snd_kcontrol_chip(kcontrol);
833 
834 	value->value.enumerated.item[0] = dummy->iobox;
835 	return 0;
836 }
837 
838 static int snd_dummy_iobox_put(struct snd_kcontrol *kcontrol,
839 			       struct snd_ctl_elem_value *value)
840 {
841 	struct snd_dummy *dummy = snd_kcontrol_chip(kcontrol);
842 	int changed;
843 
844 	if (value->value.enumerated.item[0] > 1)
845 		return -EINVAL;
846 
847 	changed = value->value.enumerated.item[0] != dummy->iobox;
848 	if (changed) {
849 		dummy->iobox = value->value.enumerated.item[0];
850 
851 		if (dummy->iobox) {
852 			dummy->cd_volume_ctl->vd[0].access &=
853 				~SNDRV_CTL_ELEM_ACCESS_INACTIVE;
854 			dummy->cd_switch_ctl->vd[0].access &=
855 				~SNDRV_CTL_ELEM_ACCESS_INACTIVE;
856 		} else {
857 			dummy->cd_volume_ctl->vd[0].access |=
858 				SNDRV_CTL_ELEM_ACCESS_INACTIVE;
859 			dummy->cd_switch_ctl->vd[0].access |=
860 				SNDRV_CTL_ELEM_ACCESS_INACTIVE;
861 		}
862 
863 		snd_ctl_notify(dummy->card, SNDRV_CTL_EVENT_MASK_INFO,
864 			       &dummy->cd_volume_ctl->id);
865 		snd_ctl_notify(dummy->card, SNDRV_CTL_EVENT_MASK_INFO,
866 			       &dummy->cd_switch_ctl->id);
867 	}
868 
869 	return changed;
870 }
871 
872 static struct snd_kcontrol_new snd_dummy_controls[] = {
873 DUMMY_VOLUME("Master Volume", 0, MIXER_ADDR_MASTER),
874 DUMMY_CAPSRC("Master Capture Switch", 0, MIXER_ADDR_MASTER),
875 DUMMY_VOLUME("Synth Volume", 0, MIXER_ADDR_SYNTH),
876 DUMMY_CAPSRC("Synth Capture Switch", 0, MIXER_ADDR_SYNTH),
877 DUMMY_VOLUME("Line Volume", 0, MIXER_ADDR_LINE),
878 DUMMY_CAPSRC("Line Capture Switch", 0, MIXER_ADDR_LINE),
879 DUMMY_VOLUME("Mic Volume", 0, MIXER_ADDR_MIC),
880 DUMMY_CAPSRC("Mic Capture Switch", 0, MIXER_ADDR_MIC),
881 DUMMY_VOLUME("CD Volume", 0, MIXER_ADDR_CD),
882 DUMMY_CAPSRC("CD Capture Switch", 0, MIXER_ADDR_CD),
883 {
884 	.iface = SNDRV_CTL_ELEM_IFACE_MIXER,
885 	.name  = "External I/O Box",
886 	.info  = snd_dummy_iobox_info,
887 	.get   = snd_dummy_iobox_get,
888 	.put   = snd_dummy_iobox_put,
889 },
890 };
891 
892 static int snd_card_dummy_new_mixer(struct snd_dummy *dummy)
893 {
894 	struct snd_card *card = dummy->card;
895 	struct snd_kcontrol *kcontrol;
896 	unsigned int idx;
897 	int err;
898 
899 	spin_lock_init(&dummy->mixer_lock);
900 	strcpy(card->mixername, "Dummy Mixer");
901 	dummy->iobox = 1;
902 
903 	for (idx = 0; idx < ARRAY_SIZE(snd_dummy_controls); idx++) {
904 		kcontrol = snd_ctl_new1(&snd_dummy_controls[idx], dummy);
905 		err = snd_ctl_add(card, kcontrol);
906 		if (err < 0)
907 			return err;
908 		if (!strcmp(kcontrol->id.name, "CD Volume"))
909 			dummy->cd_volume_ctl = kcontrol;
910 		else if (!strcmp(kcontrol->id.name, "CD Capture Switch"))
911 			dummy->cd_switch_ctl = kcontrol;
912 
913 	}
914 	return 0;
915 }
916 
917 #if defined(CONFIG_SND_DEBUG) && defined(CONFIG_SND_PROC_FS)
918 /*
919  * proc interface
920  */
921 static void print_formats(struct snd_dummy *dummy,
922 			  struct snd_info_buffer *buffer)
923 {
924 	int i;
925 
926 	for (i = 0; i < SNDRV_PCM_FORMAT_LAST; i++) {
927 		if (dummy->pcm_hw.formats & (1ULL << i))
928 			snd_iprintf(buffer, " %s", snd_pcm_format_name(i));
929 	}
930 }
931 
932 static void print_rates(struct snd_dummy *dummy,
933 			struct snd_info_buffer *buffer)
934 {
935 	static int rates[] = {
936 		5512, 8000, 11025, 16000, 22050, 32000, 44100, 48000,
937 		64000, 88200, 96000, 176400, 192000,
938 	};
939 	int i;
940 
941 	if (dummy->pcm_hw.rates & SNDRV_PCM_RATE_CONTINUOUS)
942 		snd_iprintf(buffer, " continuous");
943 	if (dummy->pcm_hw.rates & SNDRV_PCM_RATE_KNOT)
944 		snd_iprintf(buffer, " knot");
945 	for (i = 0; i < ARRAY_SIZE(rates); i++)
946 		if (dummy->pcm_hw.rates & (1 << i))
947 			snd_iprintf(buffer, " %d", rates[i]);
948 }
949 
950 #define get_dummy_int_ptr(dummy, ofs) \
951 	(unsigned int *)((char *)&((dummy)->pcm_hw) + (ofs))
952 #define get_dummy_ll_ptr(dummy, ofs) \
953 	(unsigned long long *)((char *)&((dummy)->pcm_hw) + (ofs))
954 
955 struct dummy_hw_field {
956 	const char *name;
957 	const char *format;
958 	unsigned int offset;
959 	unsigned int size;
960 };
961 #define FIELD_ENTRY(item, fmt) {		   \
962 	.name = #item,				   \
963 	.format = fmt,				   \
964 	.offset = offsetof(struct snd_pcm_hardware, item), \
965 	.size = sizeof(dummy_pcm_hardware.item) }
966 
967 static struct dummy_hw_field fields[] = {
968 	FIELD_ENTRY(formats, "%#llx"),
969 	FIELD_ENTRY(rates, "%#x"),
970 	FIELD_ENTRY(rate_min, "%d"),
971 	FIELD_ENTRY(rate_max, "%d"),
972 	FIELD_ENTRY(channels_min, "%d"),
973 	FIELD_ENTRY(channels_max, "%d"),
974 	FIELD_ENTRY(buffer_bytes_max, "%ld"),
975 	FIELD_ENTRY(period_bytes_min, "%ld"),
976 	FIELD_ENTRY(period_bytes_max, "%ld"),
977 	FIELD_ENTRY(periods_min, "%d"),
978 	FIELD_ENTRY(periods_max, "%d"),
979 };
980 
981 static void dummy_proc_read(struct snd_info_entry *entry,
982 			    struct snd_info_buffer *buffer)
983 {
984 	struct snd_dummy *dummy = entry->private_data;
985 	int i;
986 
987 	for (i = 0; i < ARRAY_SIZE(fields); i++) {
988 		snd_iprintf(buffer, "%s ", fields[i].name);
989 		if (fields[i].size == sizeof(int))
990 			snd_iprintf(buffer, fields[i].format,
991 				*get_dummy_int_ptr(dummy, fields[i].offset));
992 		else
993 			snd_iprintf(buffer, fields[i].format,
994 				*get_dummy_ll_ptr(dummy, fields[i].offset));
995 		if (!strcmp(fields[i].name, "formats"))
996 			print_formats(dummy, buffer);
997 		else if (!strcmp(fields[i].name, "rates"))
998 			print_rates(dummy, buffer);
999 		snd_iprintf(buffer, "\n");
1000 	}
1001 }
1002 
1003 static void dummy_proc_write(struct snd_info_entry *entry,
1004 			     struct snd_info_buffer *buffer)
1005 {
1006 	struct snd_dummy *dummy = entry->private_data;
1007 	char line[64];
1008 
1009 	while (!snd_info_get_line(buffer, line, sizeof(line))) {
1010 		char item[20];
1011 		const char *ptr;
1012 		unsigned long long val;
1013 		int i;
1014 
1015 		ptr = snd_info_get_str(item, line, sizeof(item));
1016 		for (i = 0; i < ARRAY_SIZE(fields); i++) {
1017 			if (!strcmp(item, fields[i].name))
1018 				break;
1019 		}
1020 		if (i >= ARRAY_SIZE(fields))
1021 			continue;
1022 		snd_info_get_str(item, ptr, sizeof(item));
1023 		if (kstrtoull(item, 0, &val))
1024 			continue;
1025 		if (fields[i].size == sizeof(int))
1026 			*get_dummy_int_ptr(dummy, fields[i].offset) = val;
1027 		else
1028 			*get_dummy_ll_ptr(dummy, fields[i].offset) = val;
1029 	}
1030 }
1031 
1032 static void dummy_proc_init(struct snd_dummy *chip)
1033 {
1034 	struct snd_info_entry *entry;
1035 
1036 	if (!snd_card_proc_new(chip->card, "dummy_pcm", &entry)) {
1037 		snd_info_set_text_ops(entry, chip, dummy_proc_read);
1038 		entry->c.text.write = dummy_proc_write;
1039 		entry->mode |= S_IWUSR;
1040 		entry->private_data = chip;
1041 	}
1042 }
1043 #else
1044 #define dummy_proc_init(x)
1045 #endif /* CONFIG_SND_DEBUG && CONFIG_SND_PROC_FS */
1046 
1047 static int snd_dummy_probe(struct platform_device *devptr)
1048 {
1049 	struct snd_card *card;
1050 	struct snd_dummy *dummy;
1051 	struct dummy_model *m = NULL, **mdl;
1052 	int idx, err;
1053 	int dev = devptr->id;
1054 
1055 	err = snd_card_new(&devptr->dev, index[dev], id[dev], THIS_MODULE,
1056 			   sizeof(struct snd_dummy), &card);
1057 	if (err < 0)
1058 		return err;
1059 	dummy = card->private_data;
1060 	dummy->card = card;
1061 	for (mdl = dummy_models; *mdl && model[dev]; mdl++) {
1062 		if (strcmp(model[dev], (*mdl)->name) == 0) {
1063 			printk(KERN_INFO
1064 				"snd-dummy: Using model '%s' for card %i\n",
1065 				(*mdl)->name, card->number);
1066 			m = dummy->model = *mdl;
1067 			break;
1068 		}
1069 	}
1070 	for (idx = 0; idx < MAX_PCM_DEVICES && idx < pcm_devs[dev]; idx++) {
1071 		if (pcm_substreams[dev] < 1)
1072 			pcm_substreams[dev] = 1;
1073 		if (pcm_substreams[dev] > MAX_PCM_SUBSTREAMS)
1074 			pcm_substreams[dev] = MAX_PCM_SUBSTREAMS;
1075 		err = snd_card_dummy_pcm(dummy, idx, pcm_substreams[dev]);
1076 		if (err < 0)
1077 			goto __nodev;
1078 	}
1079 
1080 	dummy->pcm_hw = dummy_pcm_hardware;
1081 	if (m) {
1082 		if (m->formats)
1083 			dummy->pcm_hw.formats = m->formats;
1084 		if (m->buffer_bytes_max)
1085 			dummy->pcm_hw.buffer_bytes_max = m->buffer_bytes_max;
1086 		if (m->period_bytes_min)
1087 			dummy->pcm_hw.period_bytes_min = m->period_bytes_min;
1088 		if (m->period_bytes_max)
1089 			dummy->pcm_hw.period_bytes_max = m->period_bytes_max;
1090 		if (m->periods_min)
1091 			dummy->pcm_hw.periods_min = m->periods_min;
1092 		if (m->periods_max)
1093 			dummy->pcm_hw.periods_max = m->periods_max;
1094 		if (m->rates)
1095 			dummy->pcm_hw.rates = m->rates;
1096 		if (m->rate_min)
1097 			dummy->pcm_hw.rate_min = m->rate_min;
1098 		if (m->rate_max)
1099 			dummy->pcm_hw.rate_max = m->rate_max;
1100 		if (m->channels_min)
1101 			dummy->pcm_hw.channels_min = m->channels_min;
1102 		if (m->channels_max)
1103 			dummy->pcm_hw.channels_max = m->channels_max;
1104 	}
1105 
1106 	err = snd_card_dummy_new_mixer(dummy);
1107 	if (err < 0)
1108 		goto __nodev;
1109 	strcpy(card->driver, "Dummy");
1110 	strcpy(card->shortname, "Dummy");
1111 	sprintf(card->longname, "Dummy %i", dev + 1);
1112 
1113 	dummy_proc_init(dummy);
1114 
1115 	err = snd_card_register(card);
1116 	if (err == 0) {
1117 		platform_set_drvdata(devptr, card);
1118 		return 0;
1119 	}
1120       __nodev:
1121 	snd_card_free(card);
1122 	return err;
1123 }
1124 
1125 static int snd_dummy_remove(struct platform_device *devptr)
1126 {
1127 	snd_card_free(platform_get_drvdata(devptr));
1128 	return 0;
1129 }
1130 
1131 #ifdef CONFIG_PM_SLEEP
1132 static int snd_dummy_suspend(struct device *pdev)
1133 {
1134 	struct snd_card *card = dev_get_drvdata(pdev);
1135 	struct snd_dummy *dummy = card->private_data;
1136 
1137 	snd_power_change_state(card, SNDRV_CTL_POWER_D3hot);
1138 	snd_pcm_suspend_all(dummy->pcm);
1139 	return 0;
1140 }
1141 
1142 static int snd_dummy_resume(struct device *pdev)
1143 {
1144 	struct snd_card *card = dev_get_drvdata(pdev);
1145 
1146 	snd_power_change_state(card, SNDRV_CTL_POWER_D0);
1147 	return 0;
1148 }
1149 
1150 static SIMPLE_DEV_PM_OPS(snd_dummy_pm, snd_dummy_suspend, snd_dummy_resume);
1151 #define SND_DUMMY_PM_OPS	&snd_dummy_pm
1152 #else
1153 #define SND_DUMMY_PM_OPS	NULL
1154 #endif
1155 
1156 #define SND_DUMMY_DRIVER	"snd_dummy"
1157 
1158 static struct platform_driver snd_dummy_driver = {
1159 	.probe		= snd_dummy_probe,
1160 	.remove		= snd_dummy_remove,
1161 	.driver		= {
1162 		.name	= SND_DUMMY_DRIVER,
1163 		.pm	= SND_DUMMY_PM_OPS,
1164 	},
1165 };
1166 
1167 static void snd_dummy_unregister_all(void)
1168 {
1169 	int i;
1170 
1171 	for (i = 0; i < ARRAY_SIZE(devices); ++i)
1172 		platform_device_unregister(devices[i]);
1173 	platform_driver_unregister(&snd_dummy_driver);
1174 	free_fake_buffer();
1175 }
1176 
1177 static int __init alsa_card_dummy_init(void)
1178 {
1179 	int i, cards, err;
1180 
1181 	err = platform_driver_register(&snd_dummy_driver);
1182 	if (err < 0)
1183 		return err;
1184 
1185 	err = alloc_fake_buffer();
1186 	if (err < 0) {
1187 		platform_driver_unregister(&snd_dummy_driver);
1188 		return err;
1189 	}
1190 
1191 	cards = 0;
1192 	for (i = 0; i < SNDRV_CARDS; i++) {
1193 		struct platform_device *device;
1194 		if (! enable[i])
1195 			continue;
1196 		device = platform_device_register_simple(SND_DUMMY_DRIVER,
1197 							 i, NULL, 0);
1198 		if (IS_ERR(device))
1199 			continue;
1200 		if (!platform_get_drvdata(device)) {
1201 			platform_device_unregister(device);
1202 			continue;
1203 		}
1204 		devices[i] = device;
1205 		cards++;
1206 	}
1207 	if (!cards) {
1208 #ifdef MODULE
1209 		printk(KERN_ERR "Dummy soundcard not found or device busy\n");
1210 #endif
1211 		snd_dummy_unregister_all();
1212 		return -ENODEV;
1213 	}
1214 	return 0;
1215 }
1216 
1217 static void __exit alsa_card_dummy_exit(void)
1218 {
1219 	snd_dummy_unregister_all();
1220 }
1221 
1222 module_init(alsa_card_dummy_init)
1223 module_exit(alsa_card_dummy_exit)
1224