xref: /linux/sound/drivers/dummy.c (revision 05a54fa773284d1a7923cdfdd8f0c8dabb98bd26)
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/string.h>
13 #include <linux/time.h>
14 #include <linux/wait.h>
15 #include <linux/hrtimer.h>
16 #include <linux/math64.h>
17 #include <linux/module.h>
18 #include <sound/core.h>
19 #include <sound/control.h>
20 #include <sound/tlv.h>
21 #include <sound/pcm.h>
22 #include <sound/rawmidi.h>
23 #include <sound/info.h>
24 #include <sound/initval.h>
25 
26 MODULE_AUTHOR("Jaroslav Kysela <perex@perex.cz>");
27 MODULE_DESCRIPTION("Dummy soundcard (/dev/null)");
28 MODULE_LICENSE("GPL");
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 #define USE_MIXER_VOLUME_LEVEL_MIN	-50
47 #define USE_MIXER_VOLUME_LEVEL_MAX	100
48 
49 static int index[SNDRV_CARDS] = SNDRV_DEFAULT_IDX;	/* Index 0-MAX */
50 static char *id[SNDRV_CARDS] = SNDRV_DEFAULT_STR;	/* ID for this card */
51 static bool enable[SNDRV_CARDS] = {1, [1 ... (SNDRV_CARDS - 1)] = 0};
52 static char *model[SNDRV_CARDS] = {[0 ... (SNDRV_CARDS - 1)] = NULL};
53 static int pcm_devs[SNDRV_CARDS] = {[0 ... (SNDRV_CARDS - 1)] = 1};
54 static int pcm_substreams[SNDRV_CARDS] = {[0 ... (SNDRV_CARDS - 1)] = 8};
55 //static int midi_devs[SNDRV_CARDS] = {[0 ... (SNDRV_CARDS - 1)] = 2};
56 static int mixer_volume_level_min = USE_MIXER_VOLUME_LEVEL_MIN;
57 static int mixer_volume_level_max = USE_MIXER_VOLUME_LEVEL_MAX;
58 #ifdef CONFIG_HIGH_RES_TIMERS
59 static bool hrtimer = 1;
60 #endif
61 static bool fake_buffer = 1;
62 
63 module_param_array(index, int, NULL, 0444);
64 MODULE_PARM_DESC(index, "Index value for dummy soundcard.");
65 module_param_array(id, charp, NULL, 0444);
66 MODULE_PARM_DESC(id, "ID string for dummy soundcard.");
67 module_param_array(enable, bool, NULL, 0444);
68 MODULE_PARM_DESC(enable, "Enable this dummy soundcard.");
69 module_param_array(model, charp, NULL, 0444);
70 MODULE_PARM_DESC(model, "Soundcard model.");
71 module_param_array(pcm_devs, int, NULL, 0444);
72 MODULE_PARM_DESC(pcm_devs, "PCM devices # (0-4) for dummy driver.");
73 module_param_array(pcm_substreams, int, NULL, 0444);
74 MODULE_PARM_DESC(pcm_substreams, "PCM substreams # (1-128) for dummy driver.");
75 //module_param_array(midi_devs, int, NULL, 0444);
76 //MODULE_PARM_DESC(midi_devs, "MIDI devices # (0-2) for dummy driver.");
77 module_param(mixer_volume_level_min, int, 0444);
78 MODULE_PARM_DESC(mixer_volume_level_min, "Minimum mixer volume level for dummy driver. Default: -50");
79 module_param(mixer_volume_level_max, int, 0444);
80 MODULE_PARM_DESC(mixer_volume_level_max, "Maximum mixer volume level for dummy driver. Default: 100");
81 module_param(fake_buffer, bool, 0444);
82 MODULE_PARM_DESC(fake_buffer, "Fake buffer allocations.");
83 #ifdef CONFIG_HIGH_RES_TIMERS
84 module_param(hrtimer, bool, 0644);
85 MODULE_PARM_DESC(hrtimer, "Use hrtimer as the timer source.");
86 #endif
87 
88 static struct platform_device *devices[SNDRV_CARDS];
89 
90 #define MIXER_ADDR_MASTER	0
91 #define MIXER_ADDR_LINE		1
92 #define MIXER_ADDR_MIC		2
93 #define MIXER_ADDR_SYNTH	3
94 #define MIXER_ADDR_CD		4
95 #define MIXER_ADDR_LAST		4
96 
97 struct dummy_timer_ops {
98 	int (*create)(struct snd_pcm_substream *);
99 	void (*free)(struct snd_pcm_substream *);
100 	int (*prepare)(struct snd_pcm_substream *);
101 	int (*start)(struct snd_pcm_substream *);
102 	int (*stop)(struct snd_pcm_substream *);
103 	snd_pcm_uframes_t (*pointer)(struct snd_pcm_substream *);
104 };
105 
106 #define get_dummy_ops(substream) \
107 	(*(const struct dummy_timer_ops **)(substream)->runtime->private_data)
108 
109 struct dummy_model {
110 	const char *name;
111 	int (*playback_constraints)(struct snd_pcm_runtime *runtime);
112 	int (*capture_constraints)(struct snd_pcm_runtime *runtime);
113 	u64 formats;
114 	size_t buffer_bytes_max;
115 	size_t period_bytes_min;
116 	size_t period_bytes_max;
117 	unsigned int periods_min;
118 	unsigned int periods_max;
119 	unsigned int rates;
120 	unsigned int rate_min;
121 	unsigned int rate_max;
122 	unsigned int channels_min;
123 	unsigned int channels_max;
124 };
125 
126 struct snd_dummy {
127 	struct snd_card *card;
128 	const struct dummy_model *model;
129 	struct snd_pcm *pcm;
130 	struct snd_pcm_hardware pcm_hw;
131 	spinlock_t mixer_lock;
132 	int mixer_volume[MIXER_ADDR_LAST+1][2];
133 	int capture_source[MIXER_ADDR_LAST+1][2];
134 	int iobox;
135 	struct snd_kcontrol *cd_volume_ctl;
136 	struct snd_kcontrol *cd_switch_ctl;
137 };
138 
139 /*
140  * card models
141  */
142 
143 static int emu10k1_playback_constraints(struct snd_pcm_runtime *runtime)
144 {
145 	int err;
146 	err = snd_pcm_hw_constraint_integer(runtime, SNDRV_PCM_HW_PARAM_PERIODS);
147 	if (err < 0)
148 		return err;
149 	err = snd_pcm_hw_constraint_minmax(runtime, SNDRV_PCM_HW_PARAM_BUFFER_BYTES, 256, UINT_MAX);
150 	if (err < 0)
151 		return err;
152 	return 0;
153 }
154 
155 static const struct dummy_model model_emu10k1 = {
156 	.name = "emu10k1",
157 	.playback_constraints = emu10k1_playback_constraints,
158 	.buffer_bytes_max = 128 * 1024,
159 };
160 
161 static const struct dummy_model model_rme9652 = {
162 	.name = "rme9652",
163 	.buffer_bytes_max = 26 * 64 * 1024,
164 	.formats = SNDRV_PCM_FMTBIT_S32_LE,
165 	.channels_min = 26,
166 	.channels_max = 26,
167 	.periods_min = 2,
168 	.periods_max = 2,
169 };
170 
171 static const struct dummy_model model_ice1712 = {
172 	.name = "ice1712",
173 	.buffer_bytes_max = 256 * 1024,
174 	.formats = SNDRV_PCM_FMTBIT_S32_LE,
175 	.channels_min = 10,
176 	.channels_max = 10,
177 	.periods_min = 1,
178 	.periods_max = 1024,
179 };
180 
181 static const struct dummy_model model_uda1341 = {
182 	.name = "uda1341",
183 	.buffer_bytes_max = 16380,
184 	.formats = SNDRV_PCM_FMTBIT_S16_LE,
185 	.channels_min = 2,
186 	.channels_max = 2,
187 	.periods_min = 2,
188 	.periods_max = 255,
189 };
190 
191 static const struct dummy_model model_ac97 = {
192 	.name = "ac97",
193 	.formats = SNDRV_PCM_FMTBIT_S16_LE,
194 	.channels_min = 2,
195 	.channels_max = 2,
196 	.rates = SNDRV_PCM_RATE_48000,
197 	.rate_min = 48000,
198 	.rate_max = 48000,
199 };
200 
201 static const struct dummy_model model_ca0106 = {
202 	.name = "ca0106",
203 	.formats = SNDRV_PCM_FMTBIT_S16_LE,
204 	.buffer_bytes_max = ((65536-64)*8),
205 	.period_bytes_max = (65536-64),
206 	.periods_min = 2,
207 	.periods_max = 8,
208 	.channels_min = 2,
209 	.channels_max = 2,
210 	.rates = SNDRV_PCM_RATE_48000|SNDRV_PCM_RATE_96000|SNDRV_PCM_RATE_192000,
211 	.rate_min = 48000,
212 	.rate_max = 192000,
213 };
214 
215 static const struct dummy_model *dummy_models[] = {
216 	&model_emu10k1,
217 	&model_rme9652,
218 	&model_ice1712,
219 	&model_uda1341,
220 	&model_ac97,
221 	&model_ca0106,
222 	NULL
223 };
224 
225 /*
226  * system timer interface
227  */
228 
229 struct dummy_systimer_pcm {
230 	/* ops must be the first item */
231 	const struct dummy_timer_ops *timer_ops;
232 	spinlock_t lock;
233 	struct timer_list timer;
234 	unsigned long base_time;
235 	unsigned int frac_pos;	/* fractional sample position (based HZ) */
236 	unsigned int frac_period_rest;
237 	unsigned int frac_buffer_size;	/* buffer_size * HZ */
238 	unsigned int frac_period_size;	/* period_size * HZ */
239 	unsigned int rate;
240 	int elapsed;
241 	struct snd_pcm_substream *substream;
242 };
243 
244 static void dummy_systimer_rearm(struct dummy_systimer_pcm *dpcm)
245 {
246 	mod_timer(&dpcm->timer, jiffies +
247 		DIV_ROUND_UP(dpcm->frac_period_rest, dpcm->rate));
248 }
249 
250 static void dummy_systimer_update(struct dummy_systimer_pcm *dpcm)
251 {
252 	unsigned long delta;
253 
254 	delta = jiffies - dpcm->base_time;
255 	if (!delta)
256 		return;
257 	dpcm->base_time += delta;
258 	delta *= dpcm->rate;
259 	dpcm->frac_pos += delta;
260 	while (dpcm->frac_pos >= dpcm->frac_buffer_size)
261 		dpcm->frac_pos -= dpcm->frac_buffer_size;
262 	while (dpcm->frac_period_rest <= delta) {
263 		dpcm->elapsed++;
264 		dpcm->frac_period_rest += dpcm->frac_period_size;
265 	}
266 	dpcm->frac_period_rest -= delta;
267 }
268 
269 static int dummy_systimer_start(struct snd_pcm_substream *substream)
270 {
271 	struct dummy_systimer_pcm *dpcm = substream->runtime->private_data;
272 
273 	guard(spinlock)(&dpcm->lock);
274 	dpcm->base_time = jiffies;
275 	dummy_systimer_rearm(dpcm);
276 	return 0;
277 }
278 
279 static int dummy_systimer_stop(struct snd_pcm_substream *substream)
280 {
281 	struct dummy_systimer_pcm *dpcm = substream->runtime->private_data;
282 
283 	guard(spinlock)(&dpcm->lock);
284 	timer_delete(&dpcm->timer);
285 	return 0;
286 }
287 
288 static int dummy_systimer_prepare(struct snd_pcm_substream *substream)
289 {
290 	struct snd_pcm_runtime *runtime = substream->runtime;
291 	struct dummy_systimer_pcm *dpcm = runtime->private_data;
292 
293 	dpcm->frac_pos = 0;
294 	dpcm->rate = runtime->rate;
295 	dpcm->frac_buffer_size = runtime->buffer_size * HZ;
296 	dpcm->frac_period_size = runtime->period_size * HZ;
297 	dpcm->frac_period_rest = dpcm->frac_period_size;
298 	dpcm->elapsed = 0;
299 
300 	return 0;
301 }
302 
303 static void dummy_systimer_callback(struct timer_list *t)
304 {
305 	struct dummy_systimer_pcm *dpcm = timer_container_of(dpcm, t, timer);
306 	int elapsed = 0;
307 
308 	scoped_guard(spinlock_irqsave, &dpcm->lock) {
309 		dummy_systimer_update(dpcm);
310 		dummy_systimer_rearm(dpcm);
311 		elapsed = dpcm->elapsed;
312 		dpcm->elapsed = 0;
313 	}
314 	if (elapsed)
315 		snd_pcm_period_elapsed(dpcm->substream);
316 }
317 
318 static snd_pcm_uframes_t
319 dummy_systimer_pointer(struct snd_pcm_substream *substream)
320 {
321 	struct dummy_systimer_pcm *dpcm = substream->runtime->private_data;
322 
323 	guard(spinlock)(&dpcm->lock);
324 	dummy_systimer_update(dpcm);
325 	return dpcm->frac_pos / HZ;
326 }
327 
328 static int dummy_systimer_create(struct snd_pcm_substream *substream)
329 {
330 	struct dummy_systimer_pcm *dpcm;
331 
332 	dpcm = kzalloc(sizeof(*dpcm), GFP_KERNEL);
333 	if (!dpcm)
334 		return -ENOMEM;
335 	substream->runtime->private_data = dpcm;
336 	timer_setup(&dpcm->timer, dummy_systimer_callback, 0);
337 	spin_lock_init(&dpcm->lock);
338 	dpcm->substream = substream;
339 	return 0;
340 }
341 
342 static void dummy_systimer_free(struct snd_pcm_substream *substream)
343 {
344 	kfree(substream->runtime->private_data);
345 }
346 
347 static const struct dummy_timer_ops dummy_systimer_ops = {
348 	.create =	dummy_systimer_create,
349 	.free =		dummy_systimer_free,
350 	.prepare =	dummy_systimer_prepare,
351 	.start =	dummy_systimer_start,
352 	.stop =		dummy_systimer_stop,
353 	.pointer =	dummy_systimer_pointer,
354 };
355 
356 #ifdef CONFIG_HIGH_RES_TIMERS
357 /*
358  * hrtimer interface
359  */
360 
361 struct dummy_hrtimer_pcm {
362 	/* ops must be the first item */
363 	const struct dummy_timer_ops *timer_ops;
364 	ktime_t base_time;
365 	ktime_t period_time;
366 	atomic_t running;
367 	struct hrtimer timer;
368 	struct snd_pcm_substream *substream;
369 };
370 
371 static enum hrtimer_restart dummy_hrtimer_callback(struct hrtimer *timer)
372 {
373 	struct dummy_hrtimer_pcm *dpcm;
374 
375 	dpcm = container_of(timer, struct dummy_hrtimer_pcm, timer);
376 	if (!atomic_read(&dpcm->running))
377 		return HRTIMER_NORESTART;
378 	/*
379 	 * In cases of XRUN and draining, this calls .trigger to stop PCM
380 	 * substream.
381 	 */
382 	snd_pcm_period_elapsed(dpcm->substream);
383 	if (!atomic_read(&dpcm->running))
384 		return HRTIMER_NORESTART;
385 
386 	hrtimer_forward_now(timer, dpcm->period_time);
387 	return HRTIMER_RESTART;
388 }
389 
390 static int dummy_hrtimer_start(struct snd_pcm_substream *substream)
391 {
392 	struct dummy_hrtimer_pcm *dpcm = substream->runtime->private_data;
393 
394 	dpcm->base_time = hrtimer_cb_get_time(&dpcm->timer);
395 	hrtimer_start(&dpcm->timer, dpcm->period_time, HRTIMER_MODE_REL_SOFT);
396 	atomic_set(&dpcm->running, 1);
397 	return 0;
398 }
399 
400 static int dummy_hrtimer_stop(struct snd_pcm_substream *substream)
401 {
402 	struct dummy_hrtimer_pcm *dpcm = substream->runtime->private_data;
403 
404 	atomic_set(&dpcm->running, 0);
405 	if (!hrtimer_callback_running(&dpcm->timer))
406 		hrtimer_cancel(&dpcm->timer);
407 	return 0;
408 }
409 
410 static inline void dummy_hrtimer_sync(struct dummy_hrtimer_pcm *dpcm)
411 {
412 	hrtimer_cancel(&dpcm->timer);
413 }
414 
415 static snd_pcm_uframes_t
416 dummy_hrtimer_pointer(struct snd_pcm_substream *substream)
417 {
418 	struct snd_pcm_runtime *runtime = substream->runtime;
419 	struct dummy_hrtimer_pcm *dpcm = runtime->private_data;
420 	u64 delta;
421 	u32 pos;
422 
423 	delta = ktime_us_delta(hrtimer_cb_get_time(&dpcm->timer),
424 			       dpcm->base_time);
425 	delta = div_u64(delta * runtime->rate + 999999, 1000000);
426 	div_u64_rem(delta, runtime->buffer_size, &pos);
427 	return pos;
428 }
429 
430 static int dummy_hrtimer_prepare(struct snd_pcm_substream *substream)
431 {
432 	struct snd_pcm_runtime *runtime = substream->runtime;
433 	struct dummy_hrtimer_pcm *dpcm = runtime->private_data;
434 	unsigned int period, rate;
435 	long sec;
436 	unsigned long nsecs;
437 
438 	dummy_hrtimer_sync(dpcm);
439 	period = runtime->period_size;
440 	rate = runtime->rate;
441 	sec = period / rate;
442 	period %= rate;
443 	nsecs = div_u64((u64)period * 1000000000UL + rate - 1, rate);
444 	dpcm->period_time = ktime_set(sec, nsecs);
445 
446 	return 0;
447 }
448 
449 static int dummy_hrtimer_create(struct snd_pcm_substream *substream)
450 {
451 	struct dummy_hrtimer_pcm *dpcm;
452 
453 	dpcm = kzalloc(sizeof(*dpcm), GFP_KERNEL);
454 	if (!dpcm)
455 		return -ENOMEM;
456 	substream->runtime->private_data = dpcm;
457 	hrtimer_setup(&dpcm->timer, dummy_hrtimer_callback, CLOCK_MONOTONIC, HRTIMER_MODE_REL_SOFT);
458 	dpcm->substream = substream;
459 	atomic_set(&dpcm->running, 0);
460 	return 0;
461 }
462 
463 static void dummy_hrtimer_free(struct snd_pcm_substream *substream)
464 {
465 	struct dummy_hrtimer_pcm *dpcm = substream->runtime->private_data;
466 	dummy_hrtimer_sync(dpcm);
467 	kfree(dpcm);
468 }
469 
470 static const struct dummy_timer_ops dummy_hrtimer_ops = {
471 	.create =	dummy_hrtimer_create,
472 	.free =		dummy_hrtimer_free,
473 	.prepare =	dummy_hrtimer_prepare,
474 	.start =	dummy_hrtimer_start,
475 	.stop =		dummy_hrtimer_stop,
476 	.pointer =	dummy_hrtimer_pointer,
477 };
478 
479 #endif /* CONFIG_HIGH_RES_TIMERS */
480 
481 /*
482  * PCM interface
483  */
484 
485 static int dummy_pcm_trigger(struct snd_pcm_substream *substream, int cmd)
486 {
487 	switch (cmd) {
488 	case SNDRV_PCM_TRIGGER_START:
489 	case SNDRV_PCM_TRIGGER_RESUME:
490 		return get_dummy_ops(substream)->start(substream);
491 	case SNDRV_PCM_TRIGGER_STOP:
492 	case SNDRV_PCM_TRIGGER_SUSPEND:
493 		return get_dummy_ops(substream)->stop(substream);
494 	}
495 	return -EINVAL;
496 }
497 
498 static int dummy_pcm_prepare(struct snd_pcm_substream *substream)
499 {
500 	return get_dummy_ops(substream)->prepare(substream);
501 }
502 
503 static snd_pcm_uframes_t dummy_pcm_pointer(struct snd_pcm_substream *substream)
504 {
505 	return get_dummy_ops(substream)->pointer(substream);
506 }
507 
508 static const struct snd_pcm_hardware dummy_pcm_hardware = {
509 	.info =			(SNDRV_PCM_INFO_MMAP |
510 				 SNDRV_PCM_INFO_INTERLEAVED |
511 				 SNDRV_PCM_INFO_RESUME |
512 				 SNDRV_PCM_INFO_MMAP_VALID),
513 	.formats =		USE_FORMATS,
514 	.rates =		USE_RATE,
515 	.rate_min =		USE_RATE_MIN,
516 	.rate_max =		USE_RATE_MAX,
517 	.channels_min =		USE_CHANNELS_MIN,
518 	.channels_max =		USE_CHANNELS_MAX,
519 	.buffer_bytes_max =	MAX_BUFFER_SIZE,
520 	.period_bytes_min =	MIN_PERIOD_SIZE,
521 	.period_bytes_max =	MAX_PERIOD_SIZE,
522 	.periods_min =		USE_PERIODS_MIN,
523 	.periods_max =		USE_PERIODS_MAX,
524 	.fifo_size =		0,
525 };
526 
527 static int dummy_pcm_hw_params(struct snd_pcm_substream *substream,
528 			       struct snd_pcm_hw_params *hw_params)
529 {
530 	if (fake_buffer) {
531 		/* runtime->dma_bytes has to be set manually to allow mmap */
532 		substream->runtime->dma_bytes = params_buffer_bytes(hw_params);
533 		return 0;
534 	}
535 	return 0;
536 }
537 
538 static int dummy_pcm_open(struct snd_pcm_substream *substream)
539 {
540 	struct snd_dummy *dummy = snd_pcm_substream_chip(substream);
541 	const struct dummy_model *model = dummy->model;
542 	struct snd_pcm_runtime *runtime = substream->runtime;
543 	const struct dummy_timer_ops *ops;
544 	int err;
545 
546 	ops = &dummy_systimer_ops;
547 #ifdef CONFIG_HIGH_RES_TIMERS
548 	if (hrtimer)
549 		ops = &dummy_hrtimer_ops;
550 #endif
551 
552 	err = ops->create(substream);
553 	if (err < 0)
554 		return err;
555 	get_dummy_ops(substream) = ops;
556 
557 	runtime->hw = dummy->pcm_hw;
558 	if (substream->pcm->device & 1) {
559 		runtime->hw.info &= ~SNDRV_PCM_INFO_INTERLEAVED;
560 		runtime->hw.info |= SNDRV_PCM_INFO_NONINTERLEAVED;
561 	}
562 	if (substream->pcm->device & 2)
563 		runtime->hw.info &= ~(SNDRV_PCM_INFO_MMAP |
564 				      SNDRV_PCM_INFO_MMAP_VALID);
565 
566 	if (model == NULL)
567 		return 0;
568 
569 	if (substream->stream == SNDRV_PCM_STREAM_PLAYBACK) {
570 		if (model->playback_constraints)
571 			err = model->playback_constraints(substream->runtime);
572 	} else {
573 		if (model->capture_constraints)
574 			err = model->capture_constraints(substream->runtime);
575 	}
576 	if (err < 0) {
577 		get_dummy_ops(substream)->free(substream);
578 		return err;
579 	}
580 	return 0;
581 }
582 
583 static int dummy_pcm_close(struct snd_pcm_substream *substream)
584 {
585 	get_dummy_ops(substream)->free(substream);
586 	return 0;
587 }
588 
589 /*
590  * dummy buffer handling
591  */
592 
593 static void *dummy_page[2];
594 
595 static void free_fake_buffer(void)
596 {
597 	if (fake_buffer) {
598 		int i;
599 		for (i = 0; i < 2; i++)
600 			if (dummy_page[i]) {
601 				free_page((unsigned long)dummy_page[i]);
602 				dummy_page[i] = NULL;
603 			}
604 	}
605 }
606 
607 static int alloc_fake_buffer(void)
608 {
609 	int i;
610 
611 	if (!fake_buffer)
612 		return 0;
613 	for (i = 0; i < 2; i++) {
614 		dummy_page[i] = (void *)get_zeroed_page(GFP_KERNEL);
615 		if (!dummy_page[i]) {
616 			free_fake_buffer();
617 			return -ENOMEM;
618 		}
619 	}
620 	return 0;
621 }
622 
623 static int dummy_pcm_copy(struct snd_pcm_substream *substream,
624 			  int channel, unsigned long pos,
625 			  struct iov_iter *iter, unsigned long bytes)
626 {
627 	return 0; /* do nothing */
628 }
629 
630 static int dummy_pcm_silence(struct snd_pcm_substream *substream,
631 			     int channel, unsigned long pos,
632 			     unsigned long bytes)
633 {
634 	return 0; /* do nothing */
635 }
636 
637 static struct page *dummy_pcm_page(struct snd_pcm_substream *substream,
638 				   unsigned long offset)
639 {
640 	return virt_to_page(dummy_page[substream->stream]); /* the same page */
641 }
642 
643 static const struct snd_pcm_ops dummy_pcm_ops = {
644 	.open =		dummy_pcm_open,
645 	.close =	dummy_pcm_close,
646 	.hw_params =	dummy_pcm_hw_params,
647 	.prepare =	dummy_pcm_prepare,
648 	.trigger =	dummy_pcm_trigger,
649 	.pointer =	dummy_pcm_pointer,
650 };
651 
652 static const struct snd_pcm_ops dummy_pcm_ops_no_buf = {
653 	.open =		dummy_pcm_open,
654 	.close =	dummy_pcm_close,
655 	.hw_params =	dummy_pcm_hw_params,
656 	.prepare =	dummy_pcm_prepare,
657 	.trigger =	dummy_pcm_trigger,
658 	.pointer =	dummy_pcm_pointer,
659 	.copy =		dummy_pcm_copy,
660 	.fill_silence =	dummy_pcm_silence,
661 	.page =		dummy_pcm_page,
662 };
663 
664 static int snd_card_dummy_pcm(struct snd_dummy *dummy, int device,
665 			      int substreams)
666 {
667 	struct snd_pcm *pcm;
668 	const struct snd_pcm_ops *ops;
669 	int err;
670 
671 	err = snd_pcm_new(dummy->card, "Dummy PCM", device,
672 			       substreams, substreams, &pcm);
673 	if (err < 0)
674 		return err;
675 	dummy->pcm = pcm;
676 	if (fake_buffer)
677 		ops = &dummy_pcm_ops_no_buf;
678 	else
679 		ops = &dummy_pcm_ops;
680 	snd_pcm_set_ops(pcm, SNDRV_PCM_STREAM_PLAYBACK, ops);
681 	snd_pcm_set_ops(pcm, SNDRV_PCM_STREAM_CAPTURE, ops);
682 	pcm->private_data = dummy;
683 	pcm->info_flags = 0;
684 	strscpy(pcm->name, "Dummy PCM");
685 	if (!fake_buffer) {
686 		snd_pcm_set_managed_buffer_all(pcm,
687 			SNDRV_DMA_TYPE_CONTINUOUS,
688 			NULL,
689 			0, 64*1024);
690 	}
691 	return 0;
692 }
693 
694 /*
695  * mixer interface
696  */
697 
698 #define DUMMY_VOLUME(xname, xindex, addr) \
699 { .iface = SNDRV_CTL_ELEM_IFACE_MIXER, \
700   .access = SNDRV_CTL_ELEM_ACCESS_READWRITE | SNDRV_CTL_ELEM_ACCESS_TLV_READ, \
701   .name = xname, .index = xindex, \
702   .info = snd_dummy_volume_info, \
703   .get = snd_dummy_volume_get, .put = snd_dummy_volume_put, \
704   .private_value = addr, \
705   .tlv = { .p = db_scale_dummy } }
706 
707 static int snd_dummy_volume_info(struct snd_kcontrol *kcontrol,
708 				 struct snd_ctl_elem_info *uinfo)
709 {
710 	uinfo->type = SNDRV_CTL_ELEM_TYPE_INTEGER;
711 	uinfo->count = 2;
712 	uinfo->value.integer.min = mixer_volume_level_min;
713 	uinfo->value.integer.max = mixer_volume_level_max;
714 	return 0;
715 }
716 
717 static int snd_dummy_volume_get(struct snd_kcontrol *kcontrol,
718 				struct snd_ctl_elem_value *ucontrol)
719 {
720 	struct snd_dummy *dummy = snd_kcontrol_chip(kcontrol);
721 	int addr = kcontrol->private_value;
722 
723 	guard(spinlock_irq)(&dummy->mixer_lock);
724 	ucontrol->value.integer.value[0] = dummy->mixer_volume[addr][0];
725 	ucontrol->value.integer.value[1] = dummy->mixer_volume[addr][1];
726 	return 0;
727 }
728 
729 static int snd_dummy_volume_put(struct snd_kcontrol *kcontrol,
730 				struct snd_ctl_elem_value *ucontrol)
731 {
732 	struct snd_dummy *dummy = snd_kcontrol_chip(kcontrol);
733 	int change, addr = kcontrol->private_value;
734 	int left, right;
735 
736 	left = ucontrol->value.integer.value[0];
737 	if (left < mixer_volume_level_min)
738 		left = mixer_volume_level_min;
739 	if (left > mixer_volume_level_max)
740 		left = mixer_volume_level_max;
741 	right = ucontrol->value.integer.value[1];
742 	if (right < mixer_volume_level_min)
743 		right = mixer_volume_level_min;
744 	if (right > mixer_volume_level_max)
745 		right = mixer_volume_level_max;
746 	guard(spinlock_irq)(&dummy->mixer_lock);
747 	change = dummy->mixer_volume[addr][0] != left ||
748 	         dummy->mixer_volume[addr][1] != right;
749 	dummy->mixer_volume[addr][0] = left;
750 	dummy->mixer_volume[addr][1] = right;
751 	return change;
752 }
753 
754 static const DECLARE_TLV_DB_SCALE(db_scale_dummy, -4500, 30, 0);
755 
756 #define DUMMY_CAPSRC(xname, xindex, addr) \
757 { .iface = SNDRV_CTL_ELEM_IFACE_MIXER, .name = xname, .index = xindex, \
758   .info = snd_dummy_capsrc_info, \
759   .get = snd_dummy_capsrc_get, .put = snd_dummy_capsrc_put, \
760   .private_value = addr }
761 
762 #define snd_dummy_capsrc_info	snd_ctl_boolean_stereo_info
763 
764 static int snd_dummy_capsrc_get(struct snd_kcontrol *kcontrol,
765 				struct snd_ctl_elem_value *ucontrol)
766 {
767 	struct snd_dummy *dummy = snd_kcontrol_chip(kcontrol);
768 	int addr = kcontrol->private_value;
769 
770 	guard(spinlock_irq)(&dummy->mixer_lock);
771 	ucontrol->value.integer.value[0] = dummy->capture_source[addr][0];
772 	ucontrol->value.integer.value[1] = dummy->capture_source[addr][1];
773 	return 0;
774 }
775 
776 static int snd_dummy_capsrc_put(struct snd_kcontrol *kcontrol, struct snd_ctl_elem_value *ucontrol)
777 {
778 	struct snd_dummy *dummy = snd_kcontrol_chip(kcontrol);
779 	int change, addr = kcontrol->private_value;
780 	int left, right;
781 
782 	left = ucontrol->value.integer.value[0] & 1;
783 	right = ucontrol->value.integer.value[1] & 1;
784 	guard(spinlock_irq)(&dummy->mixer_lock);
785 	change = dummy->capture_source[addr][0] != left &&
786 	         dummy->capture_source[addr][1] != right;
787 	dummy->capture_source[addr][0] = left;
788 	dummy->capture_source[addr][1] = right;
789 	return change;
790 }
791 
792 static int snd_dummy_iobox_info(struct snd_kcontrol *kcontrol,
793 				struct snd_ctl_elem_info *info)
794 {
795 	static const char *const names[] = { "None", "CD Player" };
796 
797 	return snd_ctl_enum_info(info, 1, 2, names);
798 }
799 
800 static int snd_dummy_iobox_get(struct snd_kcontrol *kcontrol,
801 			       struct snd_ctl_elem_value *value)
802 {
803 	struct snd_dummy *dummy = snd_kcontrol_chip(kcontrol);
804 
805 	value->value.enumerated.item[0] = dummy->iobox;
806 	return 0;
807 }
808 
809 static int snd_dummy_iobox_put(struct snd_kcontrol *kcontrol,
810 			       struct snd_ctl_elem_value *value)
811 {
812 	struct snd_dummy *dummy = snd_kcontrol_chip(kcontrol);
813 	int changed;
814 
815 	if (value->value.enumerated.item[0] > 1)
816 		return -EINVAL;
817 
818 	changed = value->value.enumerated.item[0] != dummy->iobox;
819 	if (changed) {
820 		dummy->iobox = value->value.enumerated.item[0];
821 
822 		if (dummy->iobox) {
823 			dummy->cd_volume_ctl->vd[0].access &=
824 				~SNDRV_CTL_ELEM_ACCESS_INACTIVE;
825 			dummy->cd_switch_ctl->vd[0].access &=
826 				~SNDRV_CTL_ELEM_ACCESS_INACTIVE;
827 		} else {
828 			dummy->cd_volume_ctl->vd[0].access |=
829 				SNDRV_CTL_ELEM_ACCESS_INACTIVE;
830 			dummy->cd_switch_ctl->vd[0].access |=
831 				SNDRV_CTL_ELEM_ACCESS_INACTIVE;
832 		}
833 
834 		snd_ctl_notify(dummy->card, SNDRV_CTL_EVENT_MASK_INFO,
835 			       &dummy->cd_volume_ctl->id);
836 		snd_ctl_notify(dummy->card, SNDRV_CTL_EVENT_MASK_INFO,
837 			       &dummy->cd_switch_ctl->id);
838 	}
839 
840 	return changed;
841 }
842 
843 static const struct snd_kcontrol_new snd_dummy_controls[] = {
844 DUMMY_VOLUME("Master Volume", 0, MIXER_ADDR_MASTER),
845 DUMMY_CAPSRC("Master Capture Switch", 0, MIXER_ADDR_MASTER),
846 DUMMY_VOLUME("Synth Volume", 0, MIXER_ADDR_SYNTH),
847 DUMMY_CAPSRC("Synth Capture Switch", 0, MIXER_ADDR_SYNTH),
848 DUMMY_VOLUME("Line Volume", 0, MIXER_ADDR_LINE),
849 DUMMY_CAPSRC("Line Capture Switch", 0, MIXER_ADDR_LINE),
850 DUMMY_VOLUME("Mic Volume", 0, MIXER_ADDR_MIC),
851 DUMMY_CAPSRC("Mic Capture Switch", 0, MIXER_ADDR_MIC),
852 DUMMY_VOLUME("CD Volume", 0, MIXER_ADDR_CD),
853 DUMMY_CAPSRC("CD Capture Switch", 0, MIXER_ADDR_CD),
854 {
855 	.iface = SNDRV_CTL_ELEM_IFACE_MIXER,
856 	.name  = "External I/O Box",
857 	.info  = snd_dummy_iobox_info,
858 	.get   = snd_dummy_iobox_get,
859 	.put   = snd_dummy_iobox_put,
860 },
861 };
862 
863 static int snd_card_dummy_new_mixer(struct snd_dummy *dummy)
864 {
865 	struct snd_card *card = dummy->card;
866 	struct snd_kcontrol *kcontrol;
867 	unsigned int idx;
868 	int err;
869 
870 	spin_lock_init(&dummy->mixer_lock);
871 	strscpy(card->mixername, "Dummy Mixer");
872 	dummy->iobox = 1;
873 
874 	for (idx = 0; idx < ARRAY_SIZE(snd_dummy_controls); idx++) {
875 		kcontrol = snd_ctl_new1(&snd_dummy_controls[idx], dummy);
876 		err = snd_ctl_add(card, kcontrol);
877 		if (err < 0)
878 			return err;
879 		if (!strcmp(kcontrol->id.name, "CD Volume"))
880 			dummy->cd_volume_ctl = kcontrol;
881 		else if (!strcmp(kcontrol->id.name, "CD Capture Switch"))
882 			dummy->cd_switch_ctl = kcontrol;
883 
884 	}
885 	return 0;
886 }
887 
888 #if defined(CONFIG_SND_DEBUG) && defined(CONFIG_SND_PROC_FS)
889 /*
890  * proc interface
891  */
892 static void print_formats(struct snd_dummy *dummy,
893 			  struct snd_info_buffer *buffer)
894 {
895 	snd_pcm_format_t i;
896 
897 	pcm_for_each_format(i) {
898 		if (dummy->pcm_hw.formats & pcm_format_to_bits(i))
899 			snd_iprintf(buffer, " %s", snd_pcm_format_name(i));
900 	}
901 }
902 
903 static void print_rates(struct snd_dummy *dummy,
904 			struct snd_info_buffer *buffer)
905 {
906 	static const int rates[] = {
907 		5512, 8000, 11025, 16000, 22050, 32000, 44100, 48000,
908 		64000, 88200, 96000, 176400, 192000,
909 	};
910 	int i;
911 
912 	if (dummy->pcm_hw.rates & SNDRV_PCM_RATE_CONTINUOUS)
913 		snd_iprintf(buffer, " continuous");
914 	if (dummy->pcm_hw.rates & SNDRV_PCM_RATE_KNOT)
915 		snd_iprintf(buffer, " knot");
916 	for (i = 0; i < ARRAY_SIZE(rates); i++)
917 		if (dummy->pcm_hw.rates & (1 << i))
918 			snd_iprintf(buffer, " %d", rates[i]);
919 }
920 
921 #define get_dummy_int_ptr(dummy, ofs) \
922 	(unsigned int *)((char *)&((dummy)->pcm_hw) + (ofs))
923 #define get_dummy_ll_ptr(dummy, ofs) \
924 	(unsigned long long *)((char *)&((dummy)->pcm_hw) + (ofs))
925 
926 struct dummy_hw_field {
927 	const char *name;
928 	const char *format;
929 	unsigned int offset;
930 	unsigned int size;
931 };
932 #define FIELD_ENTRY(item, fmt) {		   \
933 	.name = #item,				   \
934 	.format = fmt,				   \
935 	.offset = offsetof(struct snd_pcm_hardware, item), \
936 	.size = sizeof(dummy_pcm_hardware.item) }
937 
938 static const struct dummy_hw_field fields[] = {
939 	FIELD_ENTRY(formats, "%#llx"),
940 	FIELD_ENTRY(rates, "%#x"),
941 	FIELD_ENTRY(rate_min, "%d"),
942 	FIELD_ENTRY(rate_max, "%d"),
943 	FIELD_ENTRY(channels_min, "%d"),
944 	FIELD_ENTRY(channels_max, "%d"),
945 	FIELD_ENTRY(buffer_bytes_max, "%ld"),
946 	FIELD_ENTRY(period_bytes_min, "%ld"),
947 	FIELD_ENTRY(period_bytes_max, "%ld"),
948 	FIELD_ENTRY(periods_min, "%d"),
949 	FIELD_ENTRY(periods_max, "%d"),
950 };
951 
952 static void dummy_proc_read(struct snd_info_entry *entry,
953 			    struct snd_info_buffer *buffer)
954 {
955 	struct snd_dummy *dummy = entry->private_data;
956 	int i;
957 
958 	for (i = 0; i < ARRAY_SIZE(fields); i++) {
959 		snd_iprintf(buffer, "%s ", fields[i].name);
960 		if (fields[i].size == sizeof(int))
961 			snd_iprintf(buffer, fields[i].format,
962 				*get_dummy_int_ptr(dummy, fields[i].offset));
963 		else
964 			snd_iprintf(buffer, fields[i].format,
965 				*get_dummy_ll_ptr(dummy, fields[i].offset));
966 		if (!strcmp(fields[i].name, "formats"))
967 			print_formats(dummy, buffer);
968 		else if (!strcmp(fields[i].name, "rates"))
969 			print_rates(dummy, buffer);
970 		snd_iprintf(buffer, "\n");
971 	}
972 }
973 
974 static void dummy_proc_write(struct snd_info_entry *entry,
975 			     struct snd_info_buffer *buffer)
976 {
977 	struct snd_dummy *dummy = entry->private_data;
978 	char line[64];
979 
980 	while (!snd_info_get_line(buffer, line, sizeof(line))) {
981 		char item[20];
982 		const char *ptr;
983 		unsigned long long val;
984 		int i;
985 
986 		ptr = snd_info_get_str(item, line, sizeof(item));
987 		for (i = 0; i < ARRAY_SIZE(fields); i++) {
988 			if (!strcmp(item, fields[i].name))
989 				break;
990 		}
991 		if (i >= ARRAY_SIZE(fields))
992 			continue;
993 		snd_info_get_str(item, ptr, sizeof(item));
994 		if (kstrtoull(item, 0, &val))
995 			continue;
996 		if (fields[i].size == sizeof(int))
997 			*get_dummy_int_ptr(dummy, fields[i].offset) = val;
998 		else
999 			*get_dummy_ll_ptr(dummy, fields[i].offset) = val;
1000 	}
1001 }
1002 
1003 static void dummy_proc_init(struct snd_dummy *chip)
1004 {
1005 	snd_card_rw_proc_new(chip->card, "dummy_pcm", chip,
1006 			     dummy_proc_read, dummy_proc_write);
1007 }
1008 #else
1009 #define dummy_proc_init(x)
1010 #endif /* CONFIG_SND_DEBUG && CONFIG_SND_PROC_FS */
1011 
1012 static int snd_dummy_probe(struct platform_device *devptr)
1013 {
1014 	struct snd_card *card;
1015 	struct snd_dummy *dummy;
1016 	const struct dummy_model *m = NULL, **mdl;
1017 	int idx, err;
1018 	int dev = devptr->id;
1019 
1020 	err = snd_devm_card_new(&devptr->dev, index[dev], id[dev], THIS_MODULE,
1021 				sizeof(struct snd_dummy), &card);
1022 	if (err < 0)
1023 		return err;
1024 	dummy = card->private_data;
1025 	dummy->card = card;
1026 	for (mdl = dummy_models; *mdl && model[dev]; mdl++) {
1027 		if (strcmp(model[dev], (*mdl)->name) == 0) {
1028 			pr_info("snd-dummy: Using model '%s' for card %i\n",
1029 				(*mdl)->name, card->number);
1030 			m = dummy->model = *mdl;
1031 			break;
1032 		}
1033 	}
1034 	for (idx = 0; idx < MAX_PCM_DEVICES && idx < pcm_devs[dev]; idx++) {
1035 		if (pcm_substreams[dev] < 1)
1036 			pcm_substreams[dev] = 1;
1037 		if (pcm_substreams[dev] > MAX_PCM_SUBSTREAMS)
1038 			pcm_substreams[dev] = MAX_PCM_SUBSTREAMS;
1039 		err = snd_card_dummy_pcm(dummy, idx, pcm_substreams[dev]);
1040 		if (err < 0)
1041 			return err;
1042 	}
1043 
1044 	dummy->pcm_hw = dummy_pcm_hardware;
1045 	if (m) {
1046 		if (m->formats)
1047 			dummy->pcm_hw.formats = m->formats;
1048 		if (m->buffer_bytes_max)
1049 			dummy->pcm_hw.buffer_bytes_max = m->buffer_bytes_max;
1050 		if (m->period_bytes_min)
1051 			dummy->pcm_hw.period_bytes_min = m->period_bytes_min;
1052 		if (m->period_bytes_max)
1053 			dummy->pcm_hw.period_bytes_max = m->period_bytes_max;
1054 		if (m->periods_min)
1055 			dummy->pcm_hw.periods_min = m->periods_min;
1056 		if (m->periods_max)
1057 			dummy->pcm_hw.periods_max = m->periods_max;
1058 		if (m->rates)
1059 			dummy->pcm_hw.rates = m->rates;
1060 		if (m->rate_min)
1061 			dummy->pcm_hw.rate_min = m->rate_min;
1062 		if (m->rate_max)
1063 			dummy->pcm_hw.rate_max = m->rate_max;
1064 		if (m->channels_min)
1065 			dummy->pcm_hw.channels_min = m->channels_min;
1066 		if (m->channels_max)
1067 			dummy->pcm_hw.channels_max = m->channels_max;
1068 	}
1069 
1070 	if (mixer_volume_level_min > mixer_volume_level_max) {
1071 		pr_warn("snd-dummy: Invalid mixer volume level: min=%d, max=%d. Fall back to default value.\n",
1072 		mixer_volume_level_min, mixer_volume_level_max);
1073 		mixer_volume_level_min = USE_MIXER_VOLUME_LEVEL_MIN;
1074 		mixer_volume_level_max = USE_MIXER_VOLUME_LEVEL_MAX;
1075 	}
1076 	err = snd_card_dummy_new_mixer(dummy);
1077 	if (err < 0)
1078 		return err;
1079 	strscpy(card->driver, "Dummy");
1080 	strscpy(card->shortname, "Dummy");
1081 	sprintf(card->longname, "Dummy %i", dev + 1);
1082 
1083 	dummy_proc_init(dummy);
1084 
1085 	err = snd_card_register(card);
1086 	if (err < 0)
1087 		return err;
1088 	platform_set_drvdata(devptr, card);
1089 	return 0;
1090 }
1091 
1092 static int snd_dummy_suspend(struct device *pdev)
1093 {
1094 	struct snd_card *card = dev_get_drvdata(pdev);
1095 
1096 	snd_power_change_state(card, SNDRV_CTL_POWER_D3hot);
1097 	return 0;
1098 }
1099 
1100 static int snd_dummy_resume(struct device *pdev)
1101 {
1102 	struct snd_card *card = dev_get_drvdata(pdev);
1103 
1104 	snd_power_change_state(card, SNDRV_CTL_POWER_D0);
1105 	return 0;
1106 }
1107 
1108 static DEFINE_SIMPLE_DEV_PM_OPS(snd_dummy_pm, snd_dummy_suspend, snd_dummy_resume);
1109 
1110 #define SND_DUMMY_DRIVER	"snd_dummy"
1111 
1112 static struct platform_driver snd_dummy_driver = {
1113 	.probe		= snd_dummy_probe,
1114 	.driver		= {
1115 		.name	= SND_DUMMY_DRIVER,
1116 		.pm	= &snd_dummy_pm,
1117 	},
1118 };
1119 
1120 static void snd_dummy_unregister_all(void)
1121 {
1122 	int i;
1123 
1124 	for (i = 0; i < ARRAY_SIZE(devices); ++i)
1125 		platform_device_unregister(devices[i]);
1126 	platform_driver_unregister(&snd_dummy_driver);
1127 	free_fake_buffer();
1128 }
1129 
1130 static int __init alsa_card_dummy_init(void)
1131 {
1132 	int i, cards, err;
1133 
1134 	err = platform_driver_register(&snd_dummy_driver);
1135 	if (err < 0)
1136 		return err;
1137 
1138 	err = alloc_fake_buffer();
1139 	if (err < 0) {
1140 		platform_driver_unregister(&snd_dummy_driver);
1141 		return err;
1142 	}
1143 
1144 	cards = 0;
1145 	for (i = 0; i < SNDRV_CARDS; i++) {
1146 		struct platform_device *device;
1147 		if (! enable[i])
1148 			continue;
1149 		device = platform_device_register_simple(SND_DUMMY_DRIVER,
1150 							 i, NULL, 0);
1151 		if (IS_ERR(device))
1152 			continue;
1153 		if (!platform_get_drvdata(device)) {
1154 			platform_device_unregister(device);
1155 			continue;
1156 		}
1157 		devices[i] = device;
1158 		cards++;
1159 	}
1160 	if (!cards) {
1161 #ifdef MODULE
1162 		pr_err("Dummy soundcard not found or device busy\n");
1163 #endif
1164 		snd_dummy_unregister_all();
1165 		return -ENODEV;
1166 	}
1167 	return 0;
1168 }
1169 
1170 static void __exit alsa_card_dummy_exit(void)
1171 {
1172 	snd_dummy_unregister_all();
1173 }
1174 
1175 module_init(alsa_card_dummy_init)
1176 module_exit(alsa_card_dummy_exit)
1177