xref: /openbmc/linux/sound/drivers/dummy.c (revision 005f3e67)
1 // SPDX-License-Identifier: GPL-2.0-or-later
2 /*
3  *  Dummy soundcard
4  *  Copyright (c) by Jaroslav Kysela <perex@perex.cz>
5  */
6 
7 #include <linux/init.h>
8 #include <linux/err.h>
9 #include <linux/platform_device.h>
10 #include <linux/jiffies.h>
11 #include <linux/slab.h>
12 #include <linux/time.h>
13 #include <linux/wait.h>
14 #include <linux/hrtimer.h>
15 #include <linux/math64.h>
16 #include <linux/module.h>
17 #include <sound/core.h>
18 #include <sound/control.h>
19 #include <sound/tlv.h>
20 #include <sound/pcm.h>
21 #include <sound/rawmidi.h>
22 #include <sound/info.h>
23 #include <sound/initval.h>
24 
25 MODULE_AUTHOR("Jaroslav Kysela <perex@perex.cz>");
26 MODULE_DESCRIPTION("Dummy soundcard (/dev/null)");
27 MODULE_LICENSE("GPL");
28 MODULE_SUPPORTED_DEVICE("{{ALSA,Dummy soundcard}}");
29 
30 #define MAX_PCM_DEVICES		4
31 #define MAX_PCM_SUBSTREAMS	128
32 #define MAX_MIDI_DEVICES	2
33 
34 /* defaults */
35 #define MAX_BUFFER_SIZE		(64*1024)
36 #define MIN_PERIOD_SIZE		64
37 #define MAX_PERIOD_SIZE		MAX_BUFFER_SIZE
38 #define USE_FORMATS 		(SNDRV_PCM_FMTBIT_U8 | SNDRV_PCM_FMTBIT_S16_LE)
39 #define USE_RATE		SNDRV_PCM_RATE_CONTINUOUS | SNDRV_PCM_RATE_8000_48000
40 #define USE_RATE_MIN		5500
41 #define USE_RATE_MAX		48000
42 #define USE_CHANNELS_MIN 	1
43 #define USE_CHANNELS_MAX 	2
44 #define USE_PERIODS_MIN 	1
45 #define USE_PERIODS_MAX 	1024
46 
47 static int index[SNDRV_CARDS] = SNDRV_DEFAULT_IDX;	/* Index 0-MAX */
48 static char *id[SNDRV_CARDS] = SNDRV_DEFAULT_STR;	/* ID for this card */
49 static bool enable[SNDRV_CARDS] = {1, [1 ... (SNDRV_CARDS - 1)] = 0};
50 static char *model[SNDRV_CARDS] = {[0 ... (SNDRV_CARDS - 1)] = NULL};
51 static int pcm_devs[SNDRV_CARDS] = {[0 ... (SNDRV_CARDS - 1)] = 1};
52 static int pcm_substreams[SNDRV_CARDS] = {[0 ... (SNDRV_CARDS - 1)] = 8};
53 //static int midi_devs[SNDRV_CARDS] = {[0 ... (SNDRV_CARDS - 1)] = 2};
54 #ifdef CONFIG_HIGH_RES_TIMERS
55 static bool hrtimer = 1;
56 #endif
57 static bool fake_buffer = 1;
58 
59 module_param_array(index, int, NULL, 0444);
60 MODULE_PARM_DESC(index, "Index value for dummy soundcard.");
61 module_param_array(id, charp, NULL, 0444);
62 MODULE_PARM_DESC(id, "ID string for dummy soundcard.");
63 module_param_array(enable, bool, NULL, 0444);
64 MODULE_PARM_DESC(enable, "Enable this dummy soundcard.");
65 module_param_array(model, charp, NULL, 0444);
66 MODULE_PARM_DESC(model, "Soundcard model.");
67 module_param_array(pcm_devs, int, NULL, 0444);
68 MODULE_PARM_DESC(pcm_devs, "PCM devices # (0-4) for dummy driver.");
69 module_param_array(pcm_substreams, int, NULL, 0444);
70 MODULE_PARM_DESC(pcm_substreams, "PCM substreams # (1-128) for dummy driver.");
71 //module_param_array(midi_devs, int, NULL, 0444);
72 //MODULE_PARM_DESC(midi_devs, "MIDI devices # (0-2) for dummy driver.");
73 module_param(fake_buffer, bool, 0444);
74 MODULE_PARM_DESC(fake_buffer, "Fake buffer allocations.");
75 #ifdef CONFIG_HIGH_RES_TIMERS
76 module_param(hrtimer, bool, 0644);
77 MODULE_PARM_DESC(hrtimer, "Use hrtimer as the timer source.");
78 #endif
79 
80 static struct platform_device *devices[SNDRV_CARDS];
81 
82 #define MIXER_ADDR_MASTER	0
83 #define MIXER_ADDR_LINE		1
84 #define MIXER_ADDR_MIC		2
85 #define MIXER_ADDR_SYNTH	3
86 #define MIXER_ADDR_CD		4
87 #define MIXER_ADDR_LAST		4
88 
89 struct dummy_timer_ops {
90 	int (*create)(struct snd_pcm_substream *);
91 	void (*free)(struct snd_pcm_substream *);
92 	int (*prepare)(struct snd_pcm_substream *);
93 	int (*start)(struct snd_pcm_substream *);
94 	int (*stop)(struct snd_pcm_substream *);
95 	snd_pcm_uframes_t (*pointer)(struct snd_pcm_substream *);
96 };
97 
98 #define get_dummy_ops(substream) \
99 	(*(const struct dummy_timer_ops **)(substream)->runtime->private_data)
100 
101 struct dummy_model {
102 	const char *name;
103 	int (*playback_constraints)(struct snd_pcm_runtime *runtime);
104 	int (*capture_constraints)(struct snd_pcm_runtime *runtime);
105 	u64 formats;
106 	size_t buffer_bytes_max;
107 	size_t period_bytes_min;
108 	size_t period_bytes_max;
109 	unsigned int periods_min;
110 	unsigned int periods_max;
111 	unsigned int rates;
112 	unsigned int rate_min;
113 	unsigned int rate_max;
114 	unsigned int channels_min;
115 	unsigned int channels_max;
116 };
117 
118 struct snd_dummy {
119 	struct snd_card *card;
120 	struct dummy_model *model;
121 	struct snd_pcm *pcm;
122 	struct snd_pcm_hardware pcm_hw;
123 	spinlock_t mixer_lock;
124 	int mixer_volume[MIXER_ADDR_LAST+1][2];
125 	int capture_source[MIXER_ADDR_LAST+1][2];
126 	int iobox;
127 	struct snd_kcontrol *cd_volume_ctl;
128 	struct snd_kcontrol *cd_switch_ctl;
129 };
130 
131 /*
132  * card models
133  */
134 
135 static int emu10k1_playback_constraints(struct snd_pcm_runtime *runtime)
136 {
137 	int err;
138 	err = snd_pcm_hw_constraint_integer(runtime, SNDRV_PCM_HW_PARAM_PERIODS);
139 	if (err < 0)
140 		return err;
141 	err = snd_pcm_hw_constraint_minmax(runtime, SNDRV_PCM_HW_PARAM_BUFFER_BYTES, 256, UINT_MAX);
142 	if (err < 0)
143 		return err;
144 	return 0;
145 }
146 
147 static struct dummy_model model_emu10k1 = {
148 	.name = "emu10k1",
149 	.playback_constraints = emu10k1_playback_constraints,
150 	.buffer_bytes_max = 128 * 1024,
151 };
152 
153 static struct dummy_model model_rme9652 = {
154 	.name = "rme9652",
155 	.buffer_bytes_max = 26 * 64 * 1024,
156 	.formats = SNDRV_PCM_FMTBIT_S32_LE,
157 	.channels_min = 26,
158 	.channels_max = 26,
159 	.periods_min = 2,
160 	.periods_max = 2,
161 };
162 
163 static struct dummy_model model_ice1712 = {
164 	.name = "ice1712",
165 	.buffer_bytes_max = 256 * 1024,
166 	.formats = SNDRV_PCM_FMTBIT_S32_LE,
167 	.channels_min = 10,
168 	.channels_max = 10,
169 	.periods_min = 1,
170 	.periods_max = 1024,
171 };
172 
173 static struct dummy_model model_uda1341 = {
174 	.name = "uda1341",
175 	.buffer_bytes_max = 16380,
176 	.formats = SNDRV_PCM_FMTBIT_S16_LE,
177 	.channels_min = 2,
178 	.channels_max = 2,
179 	.periods_min = 2,
180 	.periods_max = 255,
181 };
182 
183 static struct dummy_model model_ac97 = {
184 	.name = "ac97",
185 	.formats = SNDRV_PCM_FMTBIT_S16_LE,
186 	.channels_min = 2,
187 	.channels_max = 2,
188 	.rates = SNDRV_PCM_RATE_48000,
189 	.rate_min = 48000,
190 	.rate_max = 48000,
191 };
192 
193 static struct dummy_model model_ca0106 = {
194 	.name = "ca0106",
195 	.formats = SNDRV_PCM_FMTBIT_S16_LE,
196 	.buffer_bytes_max = ((65536-64)*8),
197 	.period_bytes_max = (65536-64),
198 	.periods_min = 2,
199 	.periods_max = 8,
200 	.channels_min = 2,
201 	.channels_max = 2,
202 	.rates = SNDRV_PCM_RATE_48000|SNDRV_PCM_RATE_96000|SNDRV_PCM_RATE_192000,
203 	.rate_min = 48000,
204 	.rate_max = 192000,
205 };
206 
207 static struct dummy_model *dummy_models[] = {
208 	&model_emu10k1,
209 	&model_rme9652,
210 	&model_ice1712,
211 	&model_uda1341,
212 	&model_ac97,
213 	&model_ca0106,
214 	NULL
215 };
216 
217 /*
218  * system timer interface
219  */
220 
221 struct dummy_systimer_pcm {
222 	/* ops must be the first item */
223 	const struct dummy_timer_ops *timer_ops;
224 	spinlock_t lock;
225 	struct timer_list timer;
226 	unsigned long base_time;
227 	unsigned int frac_pos;	/* fractional sample position (based HZ) */
228 	unsigned int frac_period_rest;
229 	unsigned int frac_buffer_size;	/* buffer_size * HZ */
230 	unsigned int frac_period_size;	/* period_size * HZ */
231 	unsigned int rate;
232 	int elapsed;
233 	struct snd_pcm_substream *substream;
234 };
235 
236 static void dummy_systimer_rearm(struct dummy_systimer_pcm *dpcm)
237 {
238 	mod_timer(&dpcm->timer, jiffies +
239 		(dpcm->frac_period_rest + dpcm->rate - 1) / dpcm->rate);
240 }
241 
242 static void dummy_systimer_update(struct dummy_systimer_pcm *dpcm)
243 {
244 	unsigned long delta;
245 
246 	delta = jiffies - dpcm->base_time;
247 	if (!delta)
248 		return;
249 	dpcm->base_time += delta;
250 	delta *= dpcm->rate;
251 	dpcm->frac_pos += delta;
252 	while (dpcm->frac_pos >= dpcm->frac_buffer_size)
253 		dpcm->frac_pos -= dpcm->frac_buffer_size;
254 	while (dpcm->frac_period_rest <= delta) {
255 		dpcm->elapsed++;
256 		dpcm->frac_period_rest += dpcm->frac_period_size;
257 	}
258 	dpcm->frac_period_rest -= delta;
259 }
260 
261 static int dummy_systimer_start(struct snd_pcm_substream *substream)
262 {
263 	struct dummy_systimer_pcm *dpcm = substream->runtime->private_data;
264 	spin_lock(&dpcm->lock);
265 	dpcm->base_time = jiffies;
266 	dummy_systimer_rearm(dpcm);
267 	spin_unlock(&dpcm->lock);
268 	return 0;
269 }
270 
271 static int dummy_systimer_stop(struct snd_pcm_substream *substream)
272 {
273 	struct dummy_systimer_pcm *dpcm = substream->runtime->private_data;
274 	spin_lock(&dpcm->lock);
275 	del_timer(&dpcm->timer);
276 	spin_unlock(&dpcm->lock);
277 	return 0;
278 }
279 
280 static int dummy_systimer_prepare(struct snd_pcm_substream *substream)
281 {
282 	struct snd_pcm_runtime *runtime = substream->runtime;
283 	struct dummy_systimer_pcm *dpcm = runtime->private_data;
284 
285 	dpcm->frac_pos = 0;
286 	dpcm->rate = runtime->rate;
287 	dpcm->frac_buffer_size = runtime->buffer_size * HZ;
288 	dpcm->frac_period_size = runtime->period_size * HZ;
289 	dpcm->frac_period_rest = dpcm->frac_period_size;
290 	dpcm->elapsed = 0;
291 
292 	return 0;
293 }
294 
295 static void dummy_systimer_callback(struct timer_list *t)
296 {
297 	struct dummy_systimer_pcm *dpcm = from_timer(dpcm, t, timer);
298 	unsigned long flags;
299 	int elapsed = 0;
300 
301 	spin_lock_irqsave(&dpcm->lock, flags);
302 	dummy_systimer_update(dpcm);
303 	dummy_systimer_rearm(dpcm);
304 	elapsed = dpcm->elapsed;
305 	dpcm->elapsed = 0;
306 	spin_unlock_irqrestore(&dpcm->lock, flags);
307 	if (elapsed)
308 		snd_pcm_period_elapsed(dpcm->substream);
309 }
310 
311 static snd_pcm_uframes_t
312 dummy_systimer_pointer(struct snd_pcm_substream *substream)
313 {
314 	struct dummy_systimer_pcm *dpcm = substream->runtime->private_data;
315 	snd_pcm_uframes_t pos;
316 
317 	spin_lock(&dpcm->lock);
318 	dummy_systimer_update(dpcm);
319 	pos = dpcm->frac_pos / HZ;
320 	spin_unlock(&dpcm->lock);
321 	return pos;
322 }
323 
324 static int dummy_systimer_create(struct snd_pcm_substream *substream)
325 {
326 	struct dummy_systimer_pcm *dpcm;
327 
328 	dpcm = kzalloc(sizeof(*dpcm), GFP_KERNEL);
329 	if (!dpcm)
330 		return -ENOMEM;
331 	substream->runtime->private_data = dpcm;
332 	timer_setup(&dpcm->timer, dummy_systimer_callback, 0);
333 	spin_lock_init(&dpcm->lock);
334 	dpcm->substream = substream;
335 	return 0;
336 }
337 
338 static void dummy_systimer_free(struct snd_pcm_substream *substream)
339 {
340 	kfree(substream->runtime->private_data);
341 }
342 
343 static const struct dummy_timer_ops dummy_systimer_ops = {
344 	.create =	dummy_systimer_create,
345 	.free =		dummy_systimer_free,
346 	.prepare =	dummy_systimer_prepare,
347 	.start =	dummy_systimer_start,
348 	.stop =		dummy_systimer_stop,
349 	.pointer =	dummy_systimer_pointer,
350 };
351 
352 #ifdef CONFIG_HIGH_RES_TIMERS
353 /*
354  * hrtimer interface
355  */
356 
357 struct dummy_hrtimer_pcm {
358 	/* ops must be the first item */
359 	const struct dummy_timer_ops *timer_ops;
360 	ktime_t base_time;
361 	ktime_t period_time;
362 	atomic_t running;
363 	struct hrtimer timer;
364 	struct snd_pcm_substream *substream;
365 };
366 
367 static enum hrtimer_restart dummy_hrtimer_callback(struct hrtimer *timer)
368 {
369 	struct dummy_hrtimer_pcm *dpcm;
370 
371 	dpcm = container_of(timer, struct dummy_hrtimer_pcm, timer);
372 	if (!atomic_read(&dpcm->running))
373 		return HRTIMER_NORESTART;
374 	/*
375 	 * In cases of XRUN and draining, this calls .trigger to stop PCM
376 	 * substream.
377 	 */
378 	snd_pcm_period_elapsed(dpcm->substream);
379 	if (!atomic_read(&dpcm->running))
380 		return HRTIMER_NORESTART;
381 
382 	hrtimer_forward_now(timer, dpcm->period_time);
383 	return HRTIMER_RESTART;
384 }
385 
386 static int dummy_hrtimer_start(struct snd_pcm_substream *substream)
387 {
388 	struct dummy_hrtimer_pcm *dpcm = substream->runtime->private_data;
389 
390 	dpcm->base_time = hrtimer_cb_get_time(&dpcm->timer);
391 	hrtimer_start(&dpcm->timer, dpcm->period_time, HRTIMER_MODE_REL_SOFT);
392 	atomic_set(&dpcm->running, 1);
393 	return 0;
394 }
395 
396 static int dummy_hrtimer_stop(struct snd_pcm_substream *substream)
397 {
398 	struct dummy_hrtimer_pcm *dpcm = substream->runtime->private_data;
399 
400 	atomic_set(&dpcm->running, 0);
401 	if (!hrtimer_callback_running(&dpcm->timer))
402 		hrtimer_cancel(&dpcm->timer);
403 	return 0;
404 }
405 
406 static inline void dummy_hrtimer_sync(struct dummy_hrtimer_pcm *dpcm)
407 {
408 	hrtimer_cancel(&dpcm->timer);
409 }
410 
411 static snd_pcm_uframes_t
412 dummy_hrtimer_pointer(struct snd_pcm_substream *substream)
413 {
414 	struct snd_pcm_runtime *runtime = substream->runtime;
415 	struct dummy_hrtimer_pcm *dpcm = runtime->private_data;
416 	u64 delta;
417 	u32 pos;
418 
419 	delta = ktime_us_delta(hrtimer_cb_get_time(&dpcm->timer),
420 			       dpcm->base_time);
421 	delta = div_u64(delta * runtime->rate + 999999, 1000000);
422 	div_u64_rem(delta, runtime->buffer_size, &pos);
423 	return pos;
424 }
425 
426 static int dummy_hrtimer_prepare(struct snd_pcm_substream *substream)
427 {
428 	struct snd_pcm_runtime *runtime = substream->runtime;
429 	struct dummy_hrtimer_pcm *dpcm = runtime->private_data;
430 	unsigned int period, rate;
431 	long sec;
432 	unsigned long nsecs;
433 
434 	dummy_hrtimer_sync(dpcm);
435 	period = runtime->period_size;
436 	rate = runtime->rate;
437 	sec = period / rate;
438 	period %= rate;
439 	nsecs = div_u64((u64)period * 1000000000UL + rate - 1, rate);
440 	dpcm->period_time = ktime_set(sec, nsecs);
441 
442 	return 0;
443 }
444 
445 static int dummy_hrtimer_create(struct snd_pcm_substream *substream)
446 {
447 	struct dummy_hrtimer_pcm *dpcm;
448 
449 	dpcm = kzalloc(sizeof(*dpcm), GFP_KERNEL);
450 	if (!dpcm)
451 		return -ENOMEM;
452 	substream->runtime->private_data = dpcm;
453 	hrtimer_init(&dpcm->timer, CLOCK_MONOTONIC, HRTIMER_MODE_REL_SOFT);
454 	dpcm->timer.function = dummy_hrtimer_callback;
455 	dpcm->substream = substream;
456 	atomic_set(&dpcm->running, 0);
457 	return 0;
458 }
459 
460 static void dummy_hrtimer_free(struct snd_pcm_substream *substream)
461 {
462 	struct dummy_hrtimer_pcm *dpcm = substream->runtime->private_data;
463 	dummy_hrtimer_sync(dpcm);
464 	kfree(dpcm);
465 }
466 
467 static const struct dummy_timer_ops dummy_hrtimer_ops = {
468 	.create =	dummy_hrtimer_create,
469 	.free =		dummy_hrtimer_free,
470 	.prepare =	dummy_hrtimer_prepare,
471 	.start =	dummy_hrtimer_start,
472 	.stop =		dummy_hrtimer_stop,
473 	.pointer =	dummy_hrtimer_pointer,
474 };
475 
476 #endif /* CONFIG_HIGH_RES_TIMERS */
477 
478 /*
479  * PCM interface
480  */
481 
482 static int dummy_pcm_trigger(struct snd_pcm_substream *substream, int cmd)
483 {
484 	switch (cmd) {
485 	case SNDRV_PCM_TRIGGER_START:
486 	case SNDRV_PCM_TRIGGER_RESUME:
487 		return get_dummy_ops(substream)->start(substream);
488 	case SNDRV_PCM_TRIGGER_STOP:
489 	case SNDRV_PCM_TRIGGER_SUSPEND:
490 		return get_dummy_ops(substream)->stop(substream);
491 	}
492 	return -EINVAL;
493 }
494 
495 static int dummy_pcm_prepare(struct snd_pcm_substream *substream)
496 {
497 	return get_dummy_ops(substream)->prepare(substream);
498 }
499 
500 static snd_pcm_uframes_t dummy_pcm_pointer(struct snd_pcm_substream *substream)
501 {
502 	return get_dummy_ops(substream)->pointer(substream);
503 }
504 
505 static const struct snd_pcm_hardware dummy_pcm_hardware = {
506 	.info =			(SNDRV_PCM_INFO_MMAP |
507 				 SNDRV_PCM_INFO_INTERLEAVED |
508 				 SNDRV_PCM_INFO_RESUME |
509 				 SNDRV_PCM_INFO_MMAP_VALID),
510 	.formats =		USE_FORMATS,
511 	.rates =		USE_RATE,
512 	.rate_min =		USE_RATE_MIN,
513 	.rate_max =		USE_RATE_MAX,
514 	.channels_min =		USE_CHANNELS_MIN,
515 	.channels_max =		USE_CHANNELS_MAX,
516 	.buffer_bytes_max =	MAX_BUFFER_SIZE,
517 	.period_bytes_min =	MIN_PERIOD_SIZE,
518 	.period_bytes_max =	MAX_PERIOD_SIZE,
519 	.periods_min =		USE_PERIODS_MIN,
520 	.periods_max =		USE_PERIODS_MAX,
521 	.fifo_size =		0,
522 };
523 
524 static int dummy_pcm_hw_params(struct snd_pcm_substream *substream,
525 			       struct snd_pcm_hw_params *hw_params)
526 {
527 	if (fake_buffer) {
528 		/* runtime->dma_bytes has to be set manually to allow mmap */
529 		substream->runtime->dma_bytes = params_buffer_bytes(hw_params);
530 		return 0;
531 	}
532 	return 0;
533 }
534 
535 static int dummy_pcm_open(struct snd_pcm_substream *substream)
536 {
537 	struct snd_dummy *dummy = snd_pcm_substream_chip(substream);
538 	struct dummy_model *model = dummy->model;
539 	struct snd_pcm_runtime *runtime = substream->runtime;
540 	const struct dummy_timer_ops *ops;
541 	int err;
542 
543 	ops = &dummy_systimer_ops;
544 #ifdef CONFIG_HIGH_RES_TIMERS
545 	if (hrtimer)
546 		ops = &dummy_hrtimer_ops;
547 #endif
548 
549 	err = ops->create(substream);
550 	if (err < 0)
551 		return err;
552 	get_dummy_ops(substream) = ops;
553 
554 	runtime->hw = dummy->pcm_hw;
555 	if (substream->pcm->device & 1) {
556 		runtime->hw.info &= ~SNDRV_PCM_INFO_INTERLEAVED;
557 		runtime->hw.info |= SNDRV_PCM_INFO_NONINTERLEAVED;
558 	}
559 	if (substream->pcm->device & 2)
560 		runtime->hw.info &= ~(SNDRV_PCM_INFO_MMAP |
561 				      SNDRV_PCM_INFO_MMAP_VALID);
562 
563 	if (model == NULL)
564 		return 0;
565 
566 	if (substream->stream == SNDRV_PCM_STREAM_PLAYBACK) {
567 		if (model->playback_constraints)
568 			err = model->playback_constraints(substream->runtime);
569 	} else {
570 		if (model->capture_constraints)
571 			err = model->capture_constraints(substream->runtime);
572 	}
573 	if (err < 0) {
574 		get_dummy_ops(substream)->free(substream);
575 		return err;
576 	}
577 	return 0;
578 }
579 
580 static int dummy_pcm_close(struct snd_pcm_substream *substream)
581 {
582 	get_dummy_ops(substream)->free(substream);
583 	return 0;
584 }
585 
586 /*
587  * dummy buffer handling
588  */
589 
590 static void *dummy_page[2];
591 
592 static void free_fake_buffer(void)
593 {
594 	if (fake_buffer) {
595 		int i;
596 		for (i = 0; i < 2; i++)
597 			if (dummy_page[i]) {
598 				free_page((unsigned long)dummy_page[i]);
599 				dummy_page[i] = NULL;
600 			}
601 	}
602 }
603 
604 static int alloc_fake_buffer(void)
605 {
606 	int i;
607 
608 	if (!fake_buffer)
609 		return 0;
610 	for (i = 0; i < 2; i++) {
611 		dummy_page[i] = (void *)get_zeroed_page(GFP_KERNEL);
612 		if (!dummy_page[i]) {
613 			free_fake_buffer();
614 			return -ENOMEM;
615 		}
616 	}
617 	return 0;
618 }
619 
620 static int dummy_pcm_copy(struct snd_pcm_substream *substream,
621 			  int channel, unsigned long pos,
622 			  void __user *dst, unsigned long bytes)
623 {
624 	return 0; /* do nothing */
625 }
626 
627 static int dummy_pcm_copy_kernel(struct snd_pcm_substream *substream,
628 				 int channel, unsigned long pos,
629 				 void *dst, unsigned long bytes)
630 {
631 	return 0; /* do nothing */
632 }
633 
634 static int dummy_pcm_silence(struct snd_pcm_substream *substream,
635 			     int channel, unsigned long pos,
636 			     unsigned long bytes)
637 {
638 	return 0; /* do nothing */
639 }
640 
641 static struct page *dummy_pcm_page(struct snd_pcm_substream *substream,
642 				   unsigned long offset)
643 {
644 	return virt_to_page(dummy_page[substream->stream]); /* the same page */
645 }
646 
647 static struct snd_pcm_ops dummy_pcm_ops = {
648 	.open =		dummy_pcm_open,
649 	.close =	dummy_pcm_close,
650 	.ioctl =	snd_pcm_lib_ioctl,
651 	.hw_params =	dummy_pcm_hw_params,
652 	.prepare =	dummy_pcm_prepare,
653 	.trigger =	dummy_pcm_trigger,
654 	.pointer =	dummy_pcm_pointer,
655 };
656 
657 static struct snd_pcm_ops dummy_pcm_ops_no_buf = {
658 	.open =		dummy_pcm_open,
659 	.close =	dummy_pcm_close,
660 	.ioctl =	snd_pcm_lib_ioctl,
661 	.hw_params =	dummy_pcm_hw_params,
662 	.prepare =	dummy_pcm_prepare,
663 	.trigger =	dummy_pcm_trigger,
664 	.pointer =	dummy_pcm_pointer,
665 	.copy_user =	dummy_pcm_copy,
666 	.copy_kernel =	dummy_pcm_copy_kernel,
667 	.fill_silence =	dummy_pcm_silence,
668 	.page =		dummy_pcm_page,
669 };
670 
671 static int snd_card_dummy_pcm(struct snd_dummy *dummy, int device,
672 			      int substreams)
673 {
674 	struct snd_pcm *pcm;
675 	struct snd_pcm_ops *ops;
676 	int err;
677 
678 	err = snd_pcm_new(dummy->card, "Dummy PCM", device,
679 			       substreams, substreams, &pcm);
680 	if (err < 0)
681 		return err;
682 	dummy->pcm = pcm;
683 	if (fake_buffer)
684 		ops = &dummy_pcm_ops_no_buf;
685 	else
686 		ops = &dummy_pcm_ops;
687 	snd_pcm_set_ops(pcm, SNDRV_PCM_STREAM_PLAYBACK, ops);
688 	snd_pcm_set_ops(pcm, SNDRV_PCM_STREAM_CAPTURE, ops);
689 	pcm->private_data = dummy;
690 	pcm->info_flags = 0;
691 	strcpy(pcm->name, "Dummy PCM");
692 	if (!fake_buffer) {
693 		snd_pcm_set_managed_buffer_all(pcm,
694 			SNDRV_DMA_TYPE_CONTINUOUS,
695 			NULL,
696 			0, 64*1024);
697 	}
698 	return 0;
699 }
700 
701 /*
702  * mixer interface
703  */
704 
705 #define DUMMY_VOLUME(xname, xindex, addr) \
706 { .iface = SNDRV_CTL_ELEM_IFACE_MIXER, \
707   .access = SNDRV_CTL_ELEM_ACCESS_READWRITE | SNDRV_CTL_ELEM_ACCESS_TLV_READ, \
708   .name = xname, .index = xindex, \
709   .info = snd_dummy_volume_info, \
710   .get = snd_dummy_volume_get, .put = snd_dummy_volume_put, \
711   .private_value = addr, \
712   .tlv = { .p = db_scale_dummy } }
713 
714 static int snd_dummy_volume_info(struct snd_kcontrol *kcontrol,
715 				 struct snd_ctl_elem_info *uinfo)
716 {
717 	uinfo->type = SNDRV_CTL_ELEM_TYPE_INTEGER;
718 	uinfo->count = 2;
719 	uinfo->value.integer.min = -50;
720 	uinfo->value.integer.max = 100;
721 	return 0;
722 }
723 
724 static int snd_dummy_volume_get(struct snd_kcontrol *kcontrol,
725 				struct snd_ctl_elem_value *ucontrol)
726 {
727 	struct snd_dummy *dummy = snd_kcontrol_chip(kcontrol);
728 	int addr = kcontrol->private_value;
729 
730 	spin_lock_irq(&dummy->mixer_lock);
731 	ucontrol->value.integer.value[0] = dummy->mixer_volume[addr][0];
732 	ucontrol->value.integer.value[1] = dummy->mixer_volume[addr][1];
733 	spin_unlock_irq(&dummy->mixer_lock);
734 	return 0;
735 }
736 
737 static int snd_dummy_volume_put(struct snd_kcontrol *kcontrol,
738 				struct snd_ctl_elem_value *ucontrol)
739 {
740 	struct snd_dummy *dummy = snd_kcontrol_chip(kcontrol);
741 	int change, addr = kcontrol->private_value;
742 	int left, right;
743 
744 	left = ucontrol->value.integer.value[0];
745 	if (left < -50)
746 		left = -50;
747 	if (left > 100)
748 		left = 100;
749 	right = ucontrol->value.integer.value[1];
750 	if (right < -50)
751 		right = -50;
752 	if (right > 100)
753 		right = 100;
754 	spin_lock_irq(&dummy->mixer_lock);
755 	change = dummy->mixer_volume[addr][0] != left ||
756 	         dummy->mixer_volume[addr][1] != right;
757 	dummy->mixer_volume[addr][0] = left;
758 	dummy->mixer_volume[addr][1] = right;
759 	spin_unlock_irq(&dummy->mixer_lock);
760 	return change;
761 }
762 
763 static const DECLARE_TLV_DB_SCALE(db_scale_dummy, -4500, 30, 0);
764 
765 #define DUMMY_CAPSRC(xname, xindex, addr) \
766 { .iface = SNDRV_CTL_ELEM_IFACE_MIXER, .name = xname, .index = xindex, \
767   .info = snd_dummy_capsrc_info, \
768   .get = snd_dummy_capsrc_get, .put = snd_dummy_capsrc_put, \
769   .private_value = addr }
770 
771 #define snd_dummy_capsrc_info	snd_ctl_boolean_stereo_info
772 
773 static int snd_dummy_capsrc_get(struct snd_kcontrol *kcontrol,
774 				struct snd_ctl_elem_value *ucontrol)
775 {
776 	struct snd_dummy *dummy = snd_kcontrol_chip(kcontrol);
777 	int addr = kcontrol->private_value;
778 
779 	spin_lock_irq(&dummy->mixer_lock);
780 	ucontrol->value.integer.value[0] = dummy->capture_source[addr][0];
781 	ucontrol->value.integer.value[1] = dummy->capture_source[addr][1];
782 	spin_unlock_irq(&dummy->mixer_lock);
783 	return 0;
784 }
785 
786 static int snd_dummy_capsrc_put(struct snd_kcontrol *kcontrol, struct snd_ctl_elem_value *ucontrol)
787 {
788 	struct snd_dummy *dummy = snd_kcontrol_chip(kcontrol);
789 	int change, addr = kcontrol->private_value;
790 	int left, right;
791 
792 	left = ucontrol->value.integer.value[0] & 1;
793 	right = ucontrol->value.integer.value[1] & 1;
794 	spin_lock_irq(&dummy->mixer_lock);
795 	change = dummy->capture_source[addr][0] != left &&
796 	         dummy->capture_source[addr][1] != right;
797 	dummy->capture_source[addr][0] = left;
798 	dummy->capture_source[addr][1] = right;
799 	spin_unlock_irq(&dummy->mixer_lock);
800 	return change;
801 }
802 
803 static int snd_dummy_iobox_info(struct snd_kcontrol *kcontrol,
804 				struct snd_ctl_elem_info *info)
805 {
806 	static const char *const names[] = { "None", "CD Player" };
807 
808 	return snd_ctl_enum_info(info, 1, 2, names);
809 }
810 
811 static int snd_dummy_iobox_get(struct snd_kcontrol *kcontrol,
812 			       struct snd_ctl_elem_value *value)
813 {
814 	struct snd_dummy *dummy = snd_kcontrol_chip(kcontrol);
815 
816 	value->value.enumerated.item[0] = dummy->iobox;
817 	return 0;
818 }
819 
820 static int snd_dummy_iobox_put(struct snd_kcontrol *kcontrol,
821 			       struct snd_ctl_elem_value *value)
822 {
823 	struct snd_dummy *dummy = snd_kcontrol_chip(kcontrol);
824 	int changed;
825 
826 	if (value->value.enumerated.item[0] > 1)
827 		return -EINVAL;
828 
829 	changed = value->value.enumerated.item[0] != dummy->iobox;
830 	if (changed) {
831 		dummy->iobox = value->value.enumerated.item[0];
832 
833 		if (dummy->iobox) {
834 			dummy->cd_volume_ctl->vd[0].access &=
835 				~SNDRV_CTL_ELEM_ACCESS_INACTIVE;
836 			dummy->cd_switch_ctl->vd[0].access &=
837 				~SNDRV_CTL_ELEM_ACCESS_INACTIVE;
838 		} else {
839 			dummy->cd_volume_ctl->vd[0].access |=
840 				SNDRV_CTL_ELEM_ACCESS_INACTIVE;
841 			dummy->cd_switch_ctl->vd[0].access |=
842 				SNDRV_CTL_ELEM_ACCESS_INACTIVE;
843 		}
844 
845 		snd_ctl_notify(dummy->card, SNDRV_CTL_EVENT_MASK_INFO,
846 			       &dummy->cd_volume_ctl->id);
847 		snd_ctl_notify(dummy->card, SNDRV_CTL_EVENT_MASK_INFO,
848 			       &dummy->cd_switch_ctl->id);
849 	}
850 
851 	return changed;
852 }
853 
854 static struct snd_kcontrol_new snd_dummy_controls[] = {
855 DUMMY_VOLUME("Master Volume", 0, MIXER_ADDR_MASTER),
856 DUMMY_CAPSRC("Master Capture Switch", 0, MIXER_ADDR_MASTER),
857 DUMMY_VOLUME("Synth Volume", 0, MIXER_ADDR_SYNTH),
858 DUMMY_CAPSRC("Synth Capture Switch", 0, MIXER_ADDR_SYNTH),
859 DUMMY_VOLUME("Line Volume", 0, MIXER_ADDR_LINE),
860 DUMMY_CAPSRC("Line Capture Switch", 0, MIXER_ADDR_LINE),
861 DUMMY_VOLUME("Mic Volume", 0, MIXER_ADDR_MIC),
862 DUMMY_CAPSRC("Mic Capture Switch", 0, MIXER_ADDR_MIC),
863 DUMMY_VOLUME("CD Volume", 0, MIXER_ADDR_CD),
864 DUMMY_CAPSRC("CD Capture Switch", 0, MIXER_ADDR_CD),
865 {
866 	.iface = SNDRV_CTL_ELEM_IFACE_MIXER,
867 	.name  = "External I/O Box",
868 	.info  = snd_dummy_iobox_info,
869 	.get   = snd_dummy_iobox_get,
870 	.put   = snd_dummy_iobox_put,
871 },
872 };
873 
874 static int snd_card_dummy_new_mixer(struct snd_dummy *dummy)
875 {
876 	struct snd_card *card = dummy->card;
877 	struct snd_kcontrol *kcontrol;
878 	unsigned int idx;
879 	int err;
880 
881 	spin_lock_init(&dummy->mixer_lock);
882 	strcpy(card->mixername, "Dummy Mixer");
883 	dummy->iobox = 1;
884 
885 	for (idx = 0; idx < ARRAY_SIZE(snd_dummy_controls); idx++) {
886 		kcontrol = snd_ctl_new1(&snd_dummy_controls[idx], dummy);
887 		err = snd_ctl_add(card, kcontrol);
888 		if (err < 0)
889 			return err;
890 		if (!strcmp(kcontrol->id.name, "CD Volume"))
891 			dummy->cd_volume_ctl = kcontrol;
892 		else if (!strcmp(kcontrol->id.name, "CD Capture Switch"))
893 			dummy->cd_switch_ctl = kcontrol;
894 
895 	}
896 	return 0;
897 }
898 
899 #if defined(CONFIG_SND_DEBUG) && defined(CONFIG_SND_PROC_FS)
900 /*
901  * proc interface
902  */
903 static void print_formats(struct snd_dummy *dummy,
904 			  struct snd_info_buffer *buffer)
905 {
906 	int i;
907 
908 	for (i = 0; i < SNDRV_PCM_FORMAT_LAST; i++) {
909 		if (dummy->pcm_hw.formats & (1ULL << i))
910 			snd_iprintf(buffer, " %s", snd_pcm_format_name(i));
911 	}
912 }
913 
914 static void print_rates(struct snd_dummy *dummy,
915 			struct snd_info_buffer *buffer)
916 {
917 	static int rates[] = {
918 		5512, 8000, 11025, 16000, 22050, 32000, 44100, 48000,
919 		64000, 88200, 96000, 176400, 192000,
920 	};
921 	int i;
922 
923 	if (dummy->pcm_hw.rates & SNDRV_PCM_RATE_CONTINUOUS)
924 		snd_iprintf(buffer, " continuous");
925 	if (dummy->pcm_hw.rates & SNDRV_PCM_RATE_KNOT)
926 		snd_iprintf(buffer, " knot");
927 	for (i = 0; i < ARRAY_SIZE(rates); i++)
928 		if (dummy->pcm_hw.rates & (1 << i))
929 			snd_iprintf(buffer, " %d", rates[i]);
930 }
931 
932 #define get_dummy_int_ptr(dummy, ofs) \
933 	(unsigned int *)((char *)&((dummy)->pcm_hw) + (ofs))
934 #define get_dummy_ll_ptr(dummy, ofs) \
935 	(unsigned long long *)((char *)&((dummy)->pcm_hw) + (ofs))
936 
937 struct dummy_hw_field {
938 	const char *name;
939 	const char *format;
940 	unsigned int offset;
941 	unsigned int size;
942 };
943 #define FIELD_ENTRY(item, fmt) {		   \
944 	.name = #item,				   \
945 	.format = fmt,				   \
946 	.offset = offsetof(struct snd_pcm_hardware, item), \
947 	.size = sizeof(dummy_pcm_hardware.item) }
948 
949 static struct dummy_hw_field fields[] = {
950 	FIELD_ENTRY(formats, "%#llx"),
951 	FIELD_ENTRY(rates, "%#x"),
952 	FIELD_ENTRY(rate_min, "%d"),
953 	FIELD_ENTRY(rate_max, "%d"),
954 	FIELD_ENTRY(channels_min, "%d"),
955 	FIELD_ENTRY(channels_max, "%d"),
956 	FIELD_ENTRY(buffer_bytes_max, "%ld"),
957 	FIELD_ENTRY(period_bytes_min, "%ld"),
958 	FIELD_ENTRY(period_bytes_max, "%ld"),
959 	FIELD_ENTRY(periods_min, "%d"),
960 	FIELD_ENTRY(periods_max, "%d"),
961 };
962 
963 static void dummy_proc_read(struct snd_info_entry *entry,
964 			    struct snd_info_buffer *buffer)
965 {
966 	struct snd_dummy *dummy = entry->private_data;
967 	int i;
968 
969 	for (i = 0; i < ARRAY_SIZE(fields); i++) {
970 		snd_iprintf(buffer, "%s ", fields[i].name);
971 		if (fields[i].size == sizeof(int))
972 			snd_iprintf(buffer, fields[i].format,
973 				*get_dummy_int_ptr(dummy, fields[i].offset));
974 		else
975 			snd_iprintf(buffer, fields[i].format,
976 				*get_dummy_ll_ptr(dummy, fields[i].offset));
977 		if (!strcmp(fields[i].name, "formats"))
978 			print_formats(dummy, buffer);
979 		else if (!strcmp(fields[i].name, "rates"))
980 			print_rates(dummy, buffer);
981 		snd_iprintf(buffer, "\n");
982 	}
983 }
984 
985 static void dummy_proc_write(struct snd_info_entry *entry,
986 			     struct snd_info_buffer *buffer)
987 {
988 	struct snd_dummy *dummy = entry->private_data;
989 	char line[64];
990 
991 	while (!snd_info_get_line(buffer, line, sizeof(line))) {
992 		char item[20];
993 		const char *ptr;
994 		unsigned long long val;
995 		int i;
996 
997 		ptr = snd_info_get_str(item, line, sizeof(item));
998 		for (i = 0; i < ARRAY_SIZE(fields); i++) {
999 			if (!strcmp(item, fields[i].name))
1000 				break;
1001 		}
1002 		if (i >= ARRAY_SIZE(fields))
1003 			continue;
1004 		snd_info_get_str(item, ptr, sizeof(item));
1005 		if (kstrtoull(item, 0, &val))
1006 			continue;
1007 		if (fields[i].size == sizeof(int))
1008 			*get_dummy_int_ptr(dummy, fields[i].offset) = val;
1009 		else
1010 			*get_dummy_ll_ptr(dummy, fields[i].offset) = val;
1011 	}
1012 }
1013 
1014 static void dummy_proc_init(struct snd_dummy *chip)
1015 {
1016 	snd_card_rw_proc_new(chip->card, "dummy_pcm", chip,
1017 			     dummy_proc_read, dummy_proc_write);
1018 }
1019 #else
1020 #define dummy_proc_init(x)
1021 #endif /* CONFIG_SND_DEBUG && CONFIG_SND_PROC_FS */
1022 
1023 static int snd_dummy_probe(struct platform_device *devptr)
1024 {
1025 	struct snd_card *card;
1026 	struct snd_dummy *dummy;
1027 	struct dummy_model *m = NULL, **mdl;
1028 	int idx, err;
1029 	int dev = devptr->id;
1030 
1031 	err = snd_card_new(&devptr->dev, index[dev], id[dev], THIS_MODULE,
1032 			   sizeof(struct snd_dummy), &card);
1033 	if (err < 0)
1034 		return err;
1035 	dummy = card->private_data;
1036 	dummy->card = card;
1037 	for (mdl = dummy_models; *mdl && model[dev]; mdl++) {
1038 		if (strcmp(model[dev], (*mdl)->name) == 0) {
1039 			printk(KERN_INFO
1040 				"snd-dummy: Using model '%s' for card %i\n",
1041 				(*mdl)->name, card->number);
1042 			m = dummy->model = *mdl;
1043 			break;
1044 		}
1045 	}
1046 	for (idx = 0; idx < MAX_PCM_DEVICES && idx < pcm_devs[dev]; idx++) {
1047 		if (pcm_substreams[dev] < 1)
1048 			pcm_substreams[dev] = 1;
1049 		if (pcm_substreams[dev] > MAX_PCM_SUBSTREAMS)
1050 			pcm_substreams[dev] = MAX_PCM_SUBSTREAMS;
1051 		err = snd_card_dummy_pcm(dummy, idx, pcm_substreams[dev]);
1052 		if (err < 0)
1053 			goto __nodev;
1054 	}
1055 
1056 	dummy->pcm_hw = dummy_pcm_hardware;
1057 	if (m) {
1058 		if (m->formats)
1059 			dummy->pcm_hw.formats = m->formats;
1060 		if (m->buffer_bytes_max)
1061 			dummy->pcm_hw.buffer_bytes_max = m->buffer_bytes_max;
1062 		if (m->period_bytes_min)
1063 			dummy->pcm_hw.period_bytes_min = m->period_bytes_min;
1064 		if (m->period_bytes_max)
1065 			dummy->pcm_hw.period_bytes_max = m->period_bytes_max;
1066 		if (m->periods_min)
1067 			dummy->pcm_hw.periods_min = m->periods_min;
1068 		if (m->periods_max)
1069 			dummy->pcm_hw.periods_max = m->periods_max;
1070 		if (m->rates)
1071 			dummy->pcm_hw.rates = m->rates;
1072 		if (m->rate_min)
1073 			dummy->pcm_hw.rate_min = m->rate_min;
1074 		if (m->rate_max)
1075 			dummy->pcm_hw.rate_max = m->rate_max;
1076 		if (m->channels_min)
1077 			dummy->pcm_hw.channels_min = m->channels_min;
1078 		if (m->channels_max)
1079 			dummy->pcm_hw.channels_max = m->channels_max;
1080 	}
1081 
1082 	err = snd_card_dummy_new_mixer(dummy);
1083 	if (err < 0)
1084 		goto __nodev;
1085 	strcpy(card->driver, "Dummy");
1086 	strcpy(card->shortname, "Dummy");
1087 	sprintf(card->longname, "Dummy %i", dev + 1);
1088 
1089 	dummy_proc_init(dummy);
1090 
1091 	err = snd_card_register(card);
1092 	if (err == 0) {
1093 		platform_set_drvdata(devptr, card);
1094 		return 0;
1095 	}
1096       __nodev:
1097 	snd_card_free(card);
1098 	return err;
1099 }
1100 
1101 static int snd_dummy_remove(struct platform_device *devptr)
1102 {
1103 	snd_card_free(platform_get_drvdata(devptr));
1104 	return 0;
1105 }
1106 
1107 #ifdef CONFIG_PM_SLEEP
1108 static int snd_dummy_suspend(struct device *pdev)
1109 {
1110 	struct snd_card *card = dev_get_drvdata(pdev);
1111 
1112 	snd_power_change_state(card, SNDRV_CTL_POWER_D3hot);
1113 	return 0;
1114 }
1115 
1116 static int snd_dummy_resume(struct device *pdev)
1117 {
1118 	struct snd_card *card = dev_get_drvdata(pdev);
1119 
1120 	snd_power_change_state(card, SNDRV_CTL_POWER_D0);
1121 	return 0;
1122 }
1123 
1124 static SIMPLE_DEV_PM_OPS(snd_dummy_pm, snd_dummy_suspend, snd_dummy_resume);
1125 #define SND_DUMMY_PM_OPS	&snd_dummy_pm
1126 #else
1127 #define SND_DUMMY_PM_OPS	NULL
1128 #endif
1129 
1130 #define SND_DUMMY_DRIVER	"snd_dummy"
1131 
1132 static struct platform_driver snd_dummy_driver = {
1133 	.probe		= snd_dummy_probe,
1134 	.remove		= snd_dummy_remove,
1135 	.driver		= {
1136 		.name	= SND_DUMMY_DRIVER,
1137 		.pm	= SND_DUMMY_PM_OPS,
1138 	},
1139 };
1140 
1141 static void snd_dummy_unregister_all(void)
1142 {
1143 	int i;
1144 
1145 	for (i = 0; i < ARRAY_SIZE(devices); ++i)
1146 		platform_device_unregister(devices[i]);
1147 	platform_driver_unregister(&snd_dummy_driver);
1148 	free_fake_buffer();
1149 }
1150 
1151 static int __init alsa_card_dummy_init(void)
1152 {
1153 	int i, cards, err;
1154 
1155 	err = platform_driver_register(&snd_dummy_driver);
1156 	if (err < 0)
1157 		return err;
1158 
1159 	err = alloc_fake_buffer();
1160 	if (err < 0) {
1161 		platform_driver_unregister(&snd_dummy_driver);
1162 		return err;
1163 	}
1164 
1165 	cards = 0;
1166 	for (i = 0; i < SNDRV_CARDS; i++) {
1167 		struct platform_device *device;
1168 		if (! enable[i])
1169 			continue;
1170 		device = platform_device_register_simple(SND_DUMMY_DRIVER,
1171 							 i, NULL, 0);
1172 		if (IS_ERR(device))
1173 			continue;
1174 		if (!platform_get_drvdata(device)) {
1175 			platform_device_unregister(device);
1176 			continue;
1177 		}
1178 		devices[i] = device;
1179 		cards++;
1180 	}
1181 	if (!cards) {
1182 #ifdef MODULE
1183 		printk(KERN_ERR "Dummy soundcard not found or device busy\n");
1184 #endif
1185 		snd_dummy_unregister_all();
1186 		return -ENODEV;
1187 	}
1188 	return 0;
1189 }
1190 
1191 static void __exit alsa_card_dummy_exit(void)
1192 {
1193 	snd_dummy_unregister_all();
1194 }
1195 
1196 module_init(alsa_card_dummy_init)
1197 module_exit(alsa_card_dummy_exit)
1198