xref: /linux/sound/drivers/dummy.c (revision 368cf60c36a3a311474de08e52dc6314df3b06ce)
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/hrtimer_bases.h>
17 #include <linux/math64.h>
18 #include <linux/module.h>
19 #include <sound/core.h>
20 #include <sound/control.h>
21 #include <sound/tlv.h>
22 #include <sound/pcm.h>
23 #include <sound/rawmidi.h>
24 #include <sound/info.h>
25 #include <sound/initval.h>
26 
27 MODULE_AUTHOR("Jaroslav Kysela <perex@perex.cz>");
28 MODULE_DESCRIPTION("Dummy soundcard (/dev/null)");
29 MODULE_LICENSE("GPL");
30 
31 #define MAX_PCM_DEVICES		4
32 #define MAX_PCM_SUBSTREAMS	128
33 #define MAX_MIDI_DEVICES	2
34 
35 /* defaults */
36 #define MAX_BUFFER_SIZE		(64*1024)
37 #define MIN_PERIOD_SIZE		64
38 #define MAX_PERIOD_SIZE		MAX_BUFFER_SIZE
39 #define USE_FORMATS 		(SNDRV_PCM_FMTBIT_U8 | SNDRV_PCM_FMTBIT_S16_LE)
40 #define USE_RATE		SNDRV_PCM_RATE_CONTINUOUS | SNDRV_PCM_RATE_8000_48000
41 #define USE_RATE_MIN		5500
42 #define USE_RATE_MAX		48000
43 #define USE_CHANNELS_MIN 	1
44 #define USE_CHANNELS_MAX 	2
45 #define USE_PERIODS_MIN 	1
46 #define USE_PERIODS_MAX 	1024
47 #define USE_MIXER_VOLUME_LEVEL_MIN	-50
48 #define USE_MIXER_VOLUME_LEVEL_MAX	100
49 
50 static int index[SNDRV_CARDS] = SNDRV_DEFAULT_IDX;	/* Index 0-MAX */
51 static char *id[SNDRV_CARDS] = SNDRV_DEFAULT_STR;	/* ID for this card */
52 static bool enable[SNDRV_CARDS] = {1, [1 ... (SNDRV_CARDS - 1)] = 0};
53 static char *model[SNDRV_CARDS] = {[0 ... (SNDRV_CARDS - 1)] = NULL};
54 static int pcm_devs[SNDRV_CARDS] = {[0 ... (SNDRV_CARDS - 1)] = 1};
55 static int pcm_substreams[SNDRV_CARDS] = {[0 ... (SNDRV_CARDS - 1)] = 8};
56 //static int midi_devs[SNDRV_CARDS] = {[0 ... (SNDRV_CARDS - 1)] = 2};
57 static int mixer_volume_level_min = USE_MIXER_VOLUME_LEVEL_MIN;
58 static int mixer_volume_level_max = USE_MIXER_VOLUME_LEVEL_MAX;
59 #ifdef CONFIG_HIGH_RES_TIMERS
60 static bool hrtimer = 1;
61 #endif
62 static bool fake_buffer = 1;
63 
64 module_param_array(index, int, NULL, 0444);
65 MODULE_PARM_DESC(index, "Index value for dummy soundcard.");
66 module_param_array(id, charp, NULL, 0444);
67 MODULE_PARM_DESC(id, "ID string for dummy soundcard.");
68 module_param_array(enable, bool, NULL, 0444);
69 MODULE_PARM_DESC(enable, "Enable this dummy soundcard.");
70 module_param_array(model, charp, NULL, 0444);
71 MODULE_PARM_DESC(model, "Soundcard model.");
72 module_param_array(pcm_devs, int, NULL, 0444);
73 MODULE_PARM_DESC(pcm_devs, "PCM devices # (0-4) for dummy driver.");
74 module_param_array(pcm_substreams, int, NULL, 0444);
75 MODULE_PARM_DESC(pcm_substreams, "PCM substreams # (1-128) for dummy driver.");
76 //module_param_array(midi_devs, int, NULL, 0444);
77 //MODULE_PARM_DESC(midi_devs, "MIDI devices # (0-2) for dummy driver.");
78 module_param(mixer_volume_level_min, int, 0444);
79 MODULE_PARM_DESC(mixer_volume_level_min, "Minimum mixer volume level for dummy driver. Default: -50");
80 module_param(mixer_volume_level_max, int, 0444);
81 MODULE_PARM_DESC(mixer_volume_level_max, "Maximum mixer volume level for dummy driver. Default: 100");
82 module_param(fake_buffer, bool, 0444);
83 MODULE_PARM_DESC(fake_buffer, "Fake buffer allocations.");
84 #ifdef CONFIG_HIGH_RES_TIMERS
85 module_param(hrtimer, bool, 0644);
86 MODULE_PARM_DESC(hrtimer, "Use hrtimer as the timer source.");
87 #endif
88 
89 static struct platform_device *devices[SNDRV_CARDS];
90 
91 #define MIXER_ADDR_MASTER	0
92 #define MIXER_ADDR_LINE		1
93 #define MIXER_ADDR_MIC		2
94 #define MIXER_ADDR_SYNTH	3
95 #define MIXER_ADDR_CD		4
96 #define MIXER_ADDR_LAST		4
97 
98 struct dummy_timer_ops {
99 	int (*create)(struct snd_pcm_substream *);
100 	void (*free)(struct snd_pcm_substream *);
101 	int (*prepare)(struct snd_pcm_substream *);
102 	int (*start)(struct snd_pcm_substream *);
103 	int (*stop)(struct snd_pcm_substream *);
104 	snd_pcm_uframes_t (*pointer)(struct snd_pcm_substream *);
105 };
106 
107 #define get_dummy_ops(substream) \
108 	(*(const struct dummy_timer_ops **)(substream)->runtime->private_data)
109 
110 struct dummy_model {
111 	const char *name;
112 	int (*playback_constraints)(struct snd_pcm_runtime *runtime);
113 	int (*capture_constraints)(struct snd_pcm_runtime *runtime);
114 	u64 formats;
115 	size_t buffer_bytes_max;
116 	size_t period_bytes_min;
117 	size_t period_bytes_max;
118 	unsigned int periods_min;
119 	unsigned int periods_max;
120 	unsigned int rates;
121 	unsigned int rate_min;
122 	unsigned int rate_max;
123 	unsigned int channels_min;
124 	unsigned int channels_max;
125 };
126 
127 struct snd_dummy {
128 	struct snd_card *card;
129 	const struct dummy_model *model;
130 	struct snd_pcm *pcm;
131 	struct snd_pcm_hardware pcm_hw;
132 	spinlock_t mixer_lock;
133 	int mixer_volume[MIXER_ADDR_LAST+1][2];
134 	int capture_source[MIXER_ADDR_LAST+1][2];
135 	int iobox;
136 	struct snd_kcontrol *cd_volume_ctl;
137 	struct snd_kcontrol *cd_switch_ctl;
138 };
139 
140 /*
141  * card models
142  */
143 
144 static int emu10k1_playback_constraints(struct snd_pcm_runtime *runtime)
145 {
146 	int err;
147 	err = snd_pcm_hw_constraint_integer(runtime, SNDRV_PCM_HW_PARAM_PERIODS);
148 	if (err < 0)
149 		return err;
150 	err = snd_pcm_hw_constraint_minmax(runtime, SNDRV_PCM_HW_PARAM_BUFFER_BYTES, 256, UINT_MAX);
151 	if (err < 0)
152 		return err;
153 	return 0;
154 }
155 
156 static const struct dummy_model model_emu10k1 = {
157 	.name = "emu10k1",
158 	.playback_constraints = emu10k1_playback_constraints,
159 	.buffer_bytes_max = 128 * 1024,
160 };
161 
162 static const struct dummy_model model_rme9652 = {
163 	.name = "rme9652",
164 	.buffer_bytes_max = 26 * 64 * 1024,
165 	.formats = SNDRV_PCM_FMTBIT_S32_LE,
166 	.channels_min = 26,
167 	.channels_max = 26,
168 	.periods_min = 2,
169 	.periods_max = 2,
170 };
171 
172 static const struct dummy_model model_ice1712 = {
173 	.name = "ice1712",
174 	.buffer_bytes_max = 256 * 1024,
175 	.formats = SNDRV_PCM_FMTBIT_S32_LE,
176 	.channels_min = 10,
177 	.channels_max = 10,
178 	.periods_min = 1,
179 	.periods_max = 1024,
180 };
181 
182 static const struct dummy_model model_uda1341 = {
183 	.name = "uda1341",
184 	.buffer_bytes_max = 16380,
185 	.formats = SNDRV_PCM_FMTBIT_S16_LE,
186 	.channels_min = 2,
187 	.channels_max = 2,
188 	.periods_min = 2,
189 	.periods_max = 255,
190 };
191 
192 static const struct dummy_model model_ac97 = {
193 	.name = "ac97",
194 	.formats = SNDRV_PCM_FMTBIT_S16_LE,
195 	.channels_min = 2,
196 	.channels_max = 2,
197 	.rates = SNDRV_PCM_RATE_48000,
198 	.rate_min = 48000,
199 	.rate_max = 48000,
200 };
201 
202 static const struct dummy_model model_ca0106 = {
203 	.name = "ca0106",
204 	.formats = SNDRV_PCM_FMTBIT_S16_LE,
205 	.buffer_bytes_max = ((65536-64)*8),
206 	.period_bytes_max = (65536-64),
207 	.periods_min = 2,
208 	.periods_max = 8,
209 	.channels_min = 2,
210 	.channels_max = 2,
211 	.rates = SNDRV_PCM_RATE_48000|SNDRV_PCM_RATE_96000|SNDRV_PCM_RATE_192000,
212 	.rate_min = 48000,
213 	.rate_max = 192000,
214 };
215 
216 static const struct dummy_model *dummy_models[] = {
217 	&model_emu10k1,
218 	&model_rme9652,
219 	&model_ice1712,
220 	&model_uda1341,
221 	&model_ac97,
222 	&model_ca0106,
223 	NULL
224 };
225 
226 /*
227  * system timer interface
228  */
229 
230 struct dummy_systimer_pcm {
231 	/* ops must be the first item */
232 	const struct dummy_timer_ops *timer_ops;
233 	spinlock_t lock;
234 	struct timer_list timer;
235 	unsigned long base_time;
236 	unsigned int frac_pos;	/* fractional sample position (based HZ) */
237 	unsigned int frac_period_rest;
238 	unsigned int frac_buffer_size;	/* buffer_size * HZ */
239 	unsigned int frac_period_size;	/* period_size * HZ */
240 	unsigned int rate;
241 	int elapsed;
242 	struct snd_pcm_substream *substream;
243 };
244 
245 static void dummy_systimer_rearm(struct dummy_systimer_pcm *dpcm)
246 {
247 	mod_timer(&dpcm->timer, jiffies +
248 		DIV_ROUND_UP(dpcm->frac_period_rest, dpcm->rate));
249 }
250 
251 static void dummy_systimer_update(struct dummy_systimer_pcm *dpcm)
252 {
253 	unsigned long delta;
254 
255 	delta = jiffies - dpcm->base_time;
256 	if (!delta)
257 		return;
258 	dpcm->base_time += delta;
259 	delta *= dpcm->rate;
260 	dpcm->frac_pos += delta;
261 	while (dpcm->frac_pos >= dpcm->frac_buffer_size)
262 		dpcm->frac_pos -= dpcm->frac_buffer_size;
263 	while (dpcm->frac_period_rest <= delta) {
264 		dpcm->elapsed++;
265 		dpcm->frac_period_rest += dpcm->frac_period_size;
266 	}
267 	dpcm->frac_period_rest -= delta;
268 }
269 
270 static int dummy_systimer_start(struct snd_pcm_substream *substream)
271 {
272 	struct dummy_systimer_pcm *dpcm = substream->runtime->private_data;
273 
274 	guard(spinlock)(&dpcm->lock);
275 	dpcm->base_time = jiffies;
276 	dummy_systimer_rearm(dpcm);
277 	return 0;
278 }
279 
280 static int dummy_systimer_stop(struct snd_pcm_substream *substream)
281 {
282 	struct dummy_systimer_pcm *dpcm = substream->runtime->private_data;
283 
284 	guard(spinlock)(&dpcm->lock);
285 	timer_delete(&dpcm->timer);
286 	return 0;
287 }
288 
289 static int dummy_systimer_prepare(struct snd_pcm_substream *substream)
290 {
291 	struct snd_pcm_runtime *runtime = substream->runtime;
292 	struct dummy_systimer_pcm *dpcm = runtime->private_data;
293 
294 	dpcm->frac_pos = 0;
295 	dpcm->rate = runtime->rate;
296 	dpcm->frac_buffer_size = runtime->buffer_size * HZ;
297 	dpcm->frac_period_size = runtime->period_size * HZ;
298 	dpcm->frac_period_rest = dpcm->frac_period_size;
299 	dpcm->elapsed = 0;
300 
301 	return 0;
302 }
303 
304 static void dummy_systimer_callback(struct timer_list *t)
305 {
306 	struct dummy_systimer_pcm *dpcm = timer_container_of(dpcm, t, timer);
307 	int elapsed = 0;
308 
309 	scoped_guard(spinlock_irqsave, &dpcm->lock) {
310 		dummy_systimer_update(dpcm);
311 		dummy_systimer_rearm(dpcm);
312 		elapsed = dpcm->elapsed;
313 		dpcm->elapsed = 0;
314 	}
315 	if (elapsed)
316 		snd_pcm_period_elapsed(dpcm->substream);
317 }
318 
319 static snd_pcm_uframes_t
320 dummy_systimer_pointer(struct snd_pcm_substream *substream)
321 {
322 	struct dummy_systimer_pcm *dpcm = substream->runtime->private_data;
323 
324 	guard(spinlock)(&dpcm->lock);
325 	dummy_systimer_update(dpcm);
326 	return dpcm->frac_pos / HZ;
327 }
328 
329 static int dummy_systimer_create(struct snd_pcm_substream *substream)
330 {
331 	struct dummy_systimer_pcm *dpcm;
332 
333 	dpcm = kzalloc_obj(*dpcm);
334 	if (!dpcm)
335 		return -ENOMEM;
336 	substream->runtime->private_data = dpcm;
337 	timer_setup(&dpcm->timer, dummy_systimer_callback, 0);
338 	spin_lock_init(&dpcm->lock);
339 	dpcm->substream = substream;
340 	return 0;
341 }
342 
343 static void dummy_systimer_free(struct snd_pcm_substream *substream)
344 {
345 	kfree(substream->runtime->private_data);
346 }
347 
348 static const struct dummy_timer_ops dummy_systimer_ops = {
349 	.create =	dummy_systimer_create,
350 	.free =		dummy_systimer_free,
351 	.prepare =	dummy_systimer_prepare,
352 	.start =	dummy_systimer_start,
353 	.stop =		dummy_systimer_stop,
354 	.pointer =	dummy_systimer_pointer,
355 };
356 
357 #ifdef CONFIG_HIGH_RES_TIMERS
358 /*
359  * hrtimer interface
360  */
361 
362 struct dummy_hrtimer_pcm {
363 	/* ops must be the first item */
364 	const struct dummy_timer_ops *timer_ops;
365 	ktime_t base_time;
366 	ktime_t period_time;
367 	atomic_t running;
368 	struct hrtimer timer;
369 	struct snd_pcm_substream *substream;
370 };
371 
372 static enum hrtimer_restart dummy_hrtimer_callback(struct hrtimer *timer)
373 {
374 	struct dummy_hrtimer_pcm *dpcm;
375 
376 	dpcm = container_of(timer, struct dummy_hrtimer_pcm, timer);
377 	if (!atomic_read(&dpcm->running))
378 		return HRTIMER_NORESTART;
379 	/*
380 	 * In cases of XRUN and draining, this calls .trigger to stop PCM
381 	 * substream.
382 	 */
383 	snd_pcm_period_elapsed(dpcm->substream);
384 	if (!atomic_read(&dpcm->running))
385 		return HRTIMER_NORESTART;
386 
387 	hrtimer_forward_now(timer, dpcm->period_time);
388 	return HRTIMER_RESTART;
389 }
390 
391 static int dummy_hrtimer_start(struct snd_pcm_substream *substream)
392 {
393 	struct dummy_hrtimer_pcm *dpcm = substream->runtime->private_data;
394 
395 	dpcm->base_time = hrtimer_cb_get_time(&dpcm->timer);
396 	hrtimer_start(&dpcm->timer, dpcm->period_time, HRTIMER_MODE_REL_SOFT);
397 	atomic_set(&dpcm->running, 1);
398 	return 0;
399 }
400 
401 static int dummy_hrtimer_stop(struct snd_pcm_substream *substream)
402 {
403 	struct dummy_hrtimer_pcm *dpcm = substream->runtime->private_data;
404 
405 	atomic_set(&dpcm->running, 0);
406 	if (!hrtimer_callback_running(&dpcm->timer))
407 		hrtimer_cancel(&dpcm->timer);
408 	return 0;
409 }
410 
411 static inline void dummy_hrtimer_sync(struct dummy_hrtimer_pcm *dpcm)
412 {
413 	hrtimer_cancel(&dpcm->timer);
414 }
415 
416 static snd_pcm_uframes_t
417 dummy_hrtimer_pointer(struct snd_pcm_substream *substream)
418 {
419 	struct snd_pcm_runtime *runtime = substream->runtime;
420 	struct dummy_hrtimer_pcm *dpcm = runtime->private_data;
421 	u64 delta;
422 	u32 pos;
423 
424 	delta = ktime_us_delta(hrtimer_cb_get_time(&dpcm->timer),
425 			       dpcm->base_time);
426 	delta = div_u64(delta * runtime->rate + 999999, 1000000);
427 	div_u64_rem(delta, runtime->buffer_size, &pos);
428 	return pos;
429 }
430 
431 static int dummy_hrtimer_prepare(struct snd_pcm_substream *substream)
432 {
433 	struct snd_pcm_runtime *runtime = substream->runtime;
434 	struct dummy_hrtimer_pcm *dpcm = runtime->private_data;
435 	unsigned int period, rate;
436 	long sec;
437 	unsigned long nsecs;
438 
439 	dummy_hrtimer_sync(dpcm);
440 	period = runtime->period_size;
441 	rate = runtime->rate;
442 	sec = period / rate;
443 	period %= rate;
444 	nsecs = div_u64((u64)period * 1000000000UL + rate - 1, rate);
445 	dpcm->period_time = ktime_set(sec, nsecs);
446 
447 	return 0;
448 }
449 
450 static int dummy_hrtimer_create(struct snd_pcm_substream *substream)
451 {
452 	struct dummy_hrtimer_pcm *dpcm;
453 
454 	dpcm = kzalloc_obj(*dpcm);
455 	if (!dpcm)
456 		return -ENOMEM;
457 	substream->runtime->private_data = dpcm;
458 	hrtimer_setup(&dpcm->timer, dummy_hrtimer_callback, CLOCK_MONOTONIC, HRTIMER_MODE_REL_SOFT);
459 	dpcm->substream = substream;
460 	atomic_set(&dpcm->running, 0);
461 	return 0;
462 }
463 
464 static void dummy_hrtimer_free(struct snd_pcm_substream *substream)
465 {
466 	struct dummy_hrtimer_pcm *dpcm = substream->runtime->private_data;
467 	dummy_hrtimer_sync(dpcm);
468 	kfree(dpcm);
469 }
470 
471 static const struct dummy_timer_ops dummy_hrtimer_ops = {
472 	.create =	dummy_hrtimer_create,
473 	.free =		dummy_hrtimer_free,
474 	.prepare =	dummy_hrtimer_prepare,
475 	.start =	dummy_hrtimer_start,
476 	.stop =		dummy_hrtimer_stop,
477 	.pointer =	dummy_hrtimer_pointer,
478 };
479 
480 #endif /* CONFIG_HIGH_RES_TIMERS */
481 
482 /*
483  * PCM interface
484  */
485 
486 static int dummy_pcm_trigger(struct snd_pcm_substream *substream, int cmd)
487 {
488 	switch (cmd) {
489 	case SNDRV_PCM_TRIGGER_START:
490 	case SNDRV_PCM_TRIGGER_RESUME:
491 		return get_dummy_ops(substream)->start(substream);
492 	case SNDRV_PCM_TRIGGER_STOP:
493 	case SNDRV_PCM_TRIGGER_SUSPEND:
494 		return get_dummy_ops(substream)->stop(substream);
495 	}
496 	return -EINVAL;
497 }
498 
499 static int dummy_pcm_prepare(struct snd_pcm_substream *substream)
500 {
501 	return get_dummy_ops(substream)->prepare(substream);
502 }
503 
504 static snd_pcm_uframes_t dummy_pcm_pointer(struct snd_pcm_substream *substream)
505 {
506 	return get_dummy_ops(substream)->pointer(substream);
507 }
508 
509 static const struct snd_pcm_hardware dummy_pcm_hardware = {
510 	.info =			(SNDRV_PCM_INFO_MMAP |
511 				 SNDRV_PCM_INFO_INTERLEAVED |
512 				 SNDRV_PCM_INFO_RESUME |
513 				 SNDRV_PCM_INFO_MMAP_VALID),
514 	.formats =		USE_FORMATS,
515 	.rates =		USE_RATE,
516 	.rate_min =		USE_RATE_MIN,
517 	.rate_max =		USE_RATE_MAX,
518 	.channels_min =		USE_CHANNELS_MIN,
519 	.channels_max =		USE_CHANNELS_MAX,
520 	.buffer_bytes_max =	MAX_BUFFER_SIZE,
521 	.period_bytes_min =	MIN_PERIOD_SIZE,
522 	.period_bytes_max =	MAX_PERIOD_SIZE,
523 	.periods_min =		USE_PERIODS_MIN,
524 	.periods_max =		USE_PERIODS_MAX,
525 	.fifo_size =		0,
526 };
527 
528 static int dummy_pcm_hw_params(struct snd_pcm_substream *substream,
529 			       struct snd_pcm_hw_params *hw_params)
530 {
531 	if (fake_buffer) {
532 		/* runtime->dma_bytes has to be set manually to allow mmap */
533 		substream->runtime->dma_bytes = params_buffer_bytes(hw_params);
534 		return 0;
535 	}
536 	return 0;
537 }
538 
539 static int dummy_pcm_open(struct snd_pcm_substream *substream)
540 {
541 	struct snd_dummy *dummy = snd_pcm_substream_chip(substream);
542 	const struct dummy_model *model = dummy->model;
543 	struct snd_pcm_runtime *runtime = substream->runtime;
544 	const struct dummy_timer_ops *ops;
545 	int err;
546 
547 	ops = &dummy_systimer_ops;
548 #ifdef CONFIG_HIGH_RES_TIMERS
549 	if (hrtimer)
550 		ops = &dummy_hrtimer_ops;
551 #endif
552 
553 	err = ops->create(substream);
554 	if (err < 0)
555 		return err;
556 	get_dummy_ops(substream) = ops;
557 
558 	runtime->hw = dummy->pcm_hw;
559 	if (substream->pcm->device & 1) {
560 		runtime->hw.info &= ~SNDRV_PCM_INFO_INTERLEAVED;
561 		runtime->hw.info |= SNDRV_PCM_INFO_NONINTERLEAVED;
562 	}
563 	if (substream->pcm->device & 2)
564 		runtime->hw.info &= ~(SNDRV_PCM_INFO_MMAP |
565 				      SNDRV_PCM_INFO_MMAP_VALID);
566 
567 	if (model == NULL)
568 		return 0;
569 
570 	if (substream->stream == SNDRV_PCM_STREAM_PLAYBACK) {
571 		if (model->playback_constraints)
572 			err = model->playback_constraints(substream->runtime);
573 	} else {
574 		if (model->capture_constraints)
575 			err = model->capture_constraints(substream->runtime);
576 	}
577 	if (err < 0) {
578 		get_dummy_ops(substream)->free(substream);
579 		return err;
580 	}
581 	return 0;
582 }
583 
584 static int dummy_pcm_close(struct snd_pcm_substream *substream)
585 {
586 	get_dummy_ops(substream)->free(substream);
587 	return 0;
588 }
589 
590 /*
591  * dummy buffer handling
592  */
593 
594 static void *dummy_page[2];
595 
596 static void free_fake_buffer(void)
597 {
598 	if (fake_buffer) {
599 		int i;
600 		for (i = 0; i < 2; i++)
601 			if (dummy_page[i]) {
602 				free_page((unsigned long)dummy_page[i]);
603 				dummy_page[i] = NULL;
604 			}
605 	}
606 }
607 
608 static int alloc_fake_buffer(void)
609 {
610 	int i;
611 
612 	if (!fake_buffer)
613 		return 0;
614 	for (i = 0; i < 2; i++) {
615 		dummy_page[i] = (void *)get_zeroed_page(GFP_KERNEL);
616 		if (!dummy_page[i]) {
617 			free_fake_buffer();
618 			return -ENOMEM;
619 		}
620 	}
621 	return 0;
622 }
623 
624 static int dummy_pcm_copy(struct snd_pcm_substream *substream,
625 			  int channel, unsigned long pos,
626 			  struct iov_iter *iter, unsigned long bytes)
627 {
628 	return 0; /* do nothing */
629 }
630 
631 static int dummy_pcm_silence(struct snd_pcm_substream *substream,
632 			     int channel, unsigned long pos,
633 			     unsigned long bytes)
634 {
635 	return 0; /* do nothing */
636 }
637 
638 static struct page *dummy_pcm_page(struct snd_pcm_substream *substream,
639 				   unsigned long offset)
640 {
641 	return virt_to_page(dummy_page[substream->stream]); /* the same page */
642 }
643 
644 static const struct snd_pcm_ops dummy_pcm_ops = {
645 	.open =		dummy_pcm_open,
646 	.close =	dummy_pcm_close,
647 	.hw_params =	dummy_pcm_hw_params,
648 	.prepare =	dummy_pcm_prepare,
649 	.trigger =	dummy_pcm_trigger,
650 	.pointer =	dummy_pcm_pointer,
651 };
652 
653 static const struct snd_pcm_ops dummy_pcm_ops_no_buf = {
654 	.open =		dummy_pcm_open,
655 	.close =	dummy_pcm_close,
656 	.hw_params =	dummy_pcm_hw_params,
657 	.prepare =	dummy_pcm_prepare,
658 	.trigger =	dummy_pcm_trigger,
659 	.pointer =	dummy_pcm_pointer,
660 	.copy =		dummy_pcm_copy,
661 	.fill_silence =	dummy_pcm_silence,
662 	.page =		dummy_pcm_page,
663 };
664 
665 static int snd_card_dummy_pcm(struct snd_dummy *dummy, int device,
666 			      int substreams)
667 {
668 	struct snd_pcm *pcm;
669 	const struct snd_pcm_ops *ops;
670 	int err;
671 
672 	err = snd_pcm_new(dummy->card, "Dummy PCM", device,
673 			       substreams, substreams, &pcm);
674 	if (err < 0)
675 		return err;
676 	dummy->pcm = pcm;
677 	if (fake_buffer)
678 		ops = &dummy_pcm_ops_no_buf;
679 	else
680 		ops = &dummy_pcm_ops;
681 	snd_pcm_set_ops(pcm, SNDRV_PCM_STREAM_PLAYBACK, ops);
682 	snd_pcm_set_ops(pcm, SNDRV_PCM_STREAM_CAPTURE, ops);
683 	pcm->private_data = dummy;
684 	pcm->info_flags = 0;
685 	strscpy(pcm->name, "Dummy PCM");
686 	if (!fake_buffer) {
687 		snd_pcm_set_managed_buffer_all(pcm,
688 			SNDRV_DMA_TYPE_CONTINUOUS,
689 			NULL,
690 			0, 64*1024);
691 	}
692 	return 0;
693 }
694 
695 /*
696  * mixer interface
697  */
698 
699 #define DUMMY_VOLUME(xname, xindex, addr) \
700 { .iface = SNDRV_CTL_ELEM_IFACE_MIXER, \
701   .access = SNDRV_CTL_ELEM_ACCESS_READWRITE | SNDRV_CTL_ELEM_ACCESS_TLV_READ, \
702   .name = xname, .index = xindex, \
703   .info = snd_dummy_volume_info, \
704   .get = snd_dummy_volume_get, .put = snd_dummy_volume_put, \
705   .private_value = addr, \
706   .tlv = { .p = db_scale_dummy } }
707 
708 static int snd_dummy_volume_info(struct snd_kcontrol *kcontrol,
709 				 struct snd_ctl_elem_info *uinfo)
710 {
711 	uinfo->type = SNDRV_CTL_ELEM_TYPE_INTEGER;
712 	uinfo->count = 2;
713 	uinfo->value.integer.min = mixer_volume_level_min;
714 	uinfo->value.integer.max = mixer_volume_level_max;
715 	return 0;
716 }
717 
718 static int snd_dummy_volume_get(struct snd_kcontrol *kcontrol,
719 				struct snd_ctl_elem_value *ucontrol)
720 {
721 	struct snd_dummy *dummy = snd_kcontrol_chip(kcontrol);
722 	int addr = kcontrol->private_value;
723 
724 	guard(spinlock_irq)(&dummy->mixer_lock);
725 	ucontrol->value.integer.value[0] = dummy->mixer_volume[addr][0];
726 	ucontrol->value.integer.value[1] = dummy->mixer_volume[addr][1];
727 	return 0;
728 }
729 
730 static int snd_dummy_volume_put(struct snd_kcontrol *kcontrol,
731 				struct snd_ctl_elem_value *ucontrol)
732 {
733 	struct snd_dummy *dummy = snd_kcontrol_chip(kcontrol);
734 	int change, addr = kcontrol->private_value;
735 	int left, right;
736 
737 	left = ucontrol->value.integer.value[0];
738 	if (left < mixer_volume_level_min)
739 		left = mixer_volume_level_min;
740 	if (left > mixer_volume_level_max)
741 		left = mixer_volume_level_max;
742 	right = ucontrol->value.integer.value[1];
743 	if (right < mixer_volume_level_min)
744 		right = mixer_volume_level_min;
745 	if (right > mixer_volume_level_max)
746 		right = mixer_volume_level_max;
747 	guard(spinlock_irq)(&dummy->mixer_lock);
748 	change = dummy->mixer_volume[addr][0] != left ||
749 	         dummy->mixer_volume[addr][1] != right;
750 	dummy->mixer_volume[addr][0] = left;
751 	dummy->mixer_volume[addr][1] = right;
752 	return change;
753 }
754 
755 static const DECLARE_TLV_DB_SCALE(db_scale_dummy, -4500, 30, 0);
756 
757 #define DUMMY_CAPSRC(xname, xindex, addr) \
758 { .iface = SNDRV_CTL_ELEM_IFACE_MIXER, .name = xname, .index = xindex, \
759   .info = snd_dummy_capsrc_info, \
760   .get = snd_dummy_capsrc_get, .put = snd_dummy_capsrc_put, \
761   .private_value = addr }
762 
763 #define snd_dummy_capsrc_info	snd_ctl_boolean_stereo_info
764 
765 static int snd_dummy_capsrc_get(struct snd_kcontrol *kcontrol,
766 				struct snd_ctl_elem_value *ucontrol)
767 {
768 	struct snd_dummy *dummy = snd_kcontrol_chip(kcontrol);
769 	int addr = kcontrol->private_value;
770 
771 	guard(spinlock_irq)(&dummy->mixer_lock);
772 	ucontrol->value.integer.value[0] = dummy->capture_source[addr][0];
773 	ucontrol->value.integer.value[1] = dummy->capture_source[addr][1];
774 	return 0;
775 }
776 
777 static int snd_dummy_capsrc_put(struct snd_kcontrol *kcontrol, struct snd_ctl_elem_value *ucontrol)
778 {
779 	struct snd_dummy *dummy = snd_kcontrol_chip(kcontrol);
780 	int change, addr = kcontrol->private_value;
781 	int left, right;
782 
783 	left = ucontrol->value.integer.value[0] & 1;
784 	right = ucontrol->value.integer.value[1] & 1;
785 	guard(spinlock_irq)(&dummy->mixer_lock);
786 	change = dummy->capture_source[addr][0] != left &&
787 	         dummy->capture_source[addr][1] != right;
788 	dummy->capture_source[addr][0] = left;
789 	dummy->capture_source[addr][1] = right;
790 	return change;
791 }
792 
793 static int snd_dummy_iobox_info(struct snd_kcontrol *kcontrol,
794 				struct snd_ctl_elem_info *info)
795 {
796 	static const char *const names[] = { "None", "CD Player" };
797 
798 	return snd_ctl_enum_info(info, 1, 2, names);
799 }
800 
801 static int snd_dummy_iobox_get(struct snd_kcontrol *kcontrol,
802 			       struct snd_ctl_elem_value *value)
803 {
804 	struct snd_dummy *dummy = snd_kcontrol_chip(kcontrol);
805 
806 	value->value.enumerated.item[0] = dummy->iobox;
807 	return 0;
808 }
809 
810 static int snd_dummy_iobox_put(struct snd_kcontrol *kcontrol,
811 			       struct snd_ctl_elem_value *value)
812 {
813 	struct snd_dummy *dummy = snd_kcontrol_chip(kcontrol);
814 	int changed;
815 
816 	if (value->value.enumerated.item[0] > 1)
817 		return -EINVAL;
818 
819 	changed = value->value.enumerated.item[0] != dummy->iobox;
820 	if (changed) {
821 		dummy->iobox = value->value.enumerated.item[0];
822 
823 		if (dummy->iobox) {
824 			dummy->cd_volume_ctl->vd[0].access &=
825 				~SNDRV_CTL_ELEM_ACCESS_INACTIVE;
826 			dummy->cd_switch_ctl->vd[0].access &=
827 				~SNDRV_CTL_ELEM_ACCESS_INACTIVE;
828 		} else {
829 			dummy->cd_volume_ctl->vd[0].access |=
830 				SNDRV_CTL_ELEM_ACCESS_INACTIVE;
831 			dummy->cd_switch_ctl->vd[0].access |=
832 				SNDRV_CTL_ELEM_ACCESS_INACTIVE;
833 		}
834 
835 		snd_ctl_notify(dummy->card, SNDRV_CTL_EVENT_MASK_INFO,
836 			       &dummy->cd_volume_ctl->id);
837 		snd_ctl_notify(dummy->card, SNDRV_CTL_EVENT_MASK_INFO,
838 			       &dummy->cd_switch_ctl->id);
839 	}
840 
841 	return changed;
842 }
843 
844 static const struct snd_kcontrol_new snd_dummy_controls[] = {
845 DUMMY_VOLUME("Master Volume", 0, MIXER_ADDR_MASTER),
846 DUMMY_CAPSRC("Master Capture Switch", 0, MIXER_ADDR_MASTER),
847 DUMMY_VOLUME("Synth Volume", 0, MIXER_ADDR_SYNTH),
848 DUMMY_CAPSRC("Synth Capture Switch", 0, MIXER_ADDR_SYNTH),
849 DUMMY_VOLUME("Line Volume", 0, MIXER_ADDR_LINE),
850 DUMMY_CAPSRC("Line Capture Switch", 0, MIXER_ADDR_LINE),
851 DUMMY_VOLUME("Mic Volume", 0, MIXER_ADDR_MIC),
852 DUMMY_CAPSRC("Mic Capture Switch", 0, MIXER_ADDR_MIC),
853 DUMMY_VOLUME("CD Volume", 0, MIXER_ADDR_CD),
854 DUMMY_CAPSRC("CD Capture Switch", 0, MIXER_ADDR_CD),
855 {
856 	.iface = SNDRV_CTL_ELEM_IFACE_MIXER,
857 	.name  = "External I/O Box",
858 	.info  = snd_dummy_iobox_info,
859 	.get   = snd_dummy_iobox_get,
860 	.put   = snd_dummy_iobox_put,
861 },
862 };
863 
864 static int snd_card_dummy_new_mixer(struct snd_dummy *dummy)
865 {
866 	struct snd_card *card = dummy->card;
867 	struct snd_kcontrol *kcontrol;
868 	unsigned int idx;
869 	int err;
870 
871 	spin_lock_init(&dummy->mixer_lock);
872 	strscpy(card->mixername, "Dummy Mixer");
873 	dummy->iobox = 1;
874 
875 	for (idx = 0; idx < ARRAY_SIZE(snd_dummy_controls); idx++) {
876 		kcontrol = snd_ctl_new1(&snd_dummy_controls[idx], dummy);
877 		err = snd_ctl_add(card, kcontrol);
878 		if (err < 0)
879 			return err;
880 		if (!strcmp(kcontrol->id.name, "CD Volume"))
881 			dummy->cd_volume_ctl = kcontrol;
882 		else if (!strcmp(kcontrol->id.name, "CD Capture Switch"))
883 			dummy->cd_switch_ctl = kcontrol;
884 
885 	}
886 	return 0;
887 }
888 
889 #if defined(CONFIG_SND_DEBUG) && defined(CONFIG_SND_PROC_FS)
890 /*
891  * proc interface
892  */
893 static void print_formats(struct snd_dummy *dummy,
894 			  struct snd_info_buffer *buffer)
895 {
896 	snd_pcm_format_t i;
897 
898 	pcm_for_each_format(i) {
899 		if (dummy->pcm_hw.formats & pcm_format_to_bits(i))
900 			snd_iprintf(buffer, " %s", snd_pcm_format_name(i));
901 	}
902 }
903 
904 static void print_rates(struct snd_dummy *dummy,
905 			struct snd_info_buffer *buffer)
906 {
907 	static const int rates[] = {
908 		5512, 8000, 11025, 16000, 22050, 32000, 44100, 48000,
909 		64000, 88200, 96000, 176400, 192000,
910 	};
911 	int i;
912 
913 	if (dummy->pcm_hw.rates & SNDRV_PCM_RATE_CONTINUOUS)
914 		snd_iprintf(buffer, " continuous");
915 	if (dummy->pcm_hw.rates & SNDRV_PCM_RATE_KNOT)
916 		snd_iprintf(buffer, " knot");
917 	for (i = 0; i < ARRAY_SIZE(rates); i++)
918 		if (dummy->pcm_hw.rates & (1 << i))
919 			snd_iprintf(buffer, " %d", rates[i]);
920 }
921 
922 #define get_dummy_int_ptr(dummy, ofs) \
923 	(unsigned int *)((char *)&((dummy)->pcm_hw) + (ofs))
924 #define get_dummy_ll_ptr(dummy, ofs) \
925 	(unsigned long long *)((char *)&((dummy)->pcm_hw) + (ofs))
926 
927 struct dummy_hw_field {
928 	const char *name;
929 	const char *format;
930 	unsigned int offset;
931 	unsigned int size;
932 };
933 #define FIELD_ENTRY(item, fmt) {		   \
934 	.name = #item,				   \
935 	.format = fmt,				   \
936 	.offset = offsetof(struct snd_pcm_hardware, item), \
937 	.size = sizeof(dummy_pcm_hardware.item) }
938 
939 static const struct dummy_hw_field fields[] = {
940 	FIELD_ENTRY(formats, "%#llx"),
941 	FIELD_ENTRY(rates, "%#x"),
942 	FIELD_ENTRY(rate_min, "%d"),
943 	FIELD_ENTRY(rate_max, "%d"),
944 	FIELD_ENTRY(channels_min, "%d"),
945 	FIELD_ENTRY(channels_max, "%d"),
946 	FIELD_ENTRY(buffer_bytes_max, "%ld"),
947 	FIELD_ENTRY(period_bytes_min, "%ld"),
948 	FIELD_ENTRY(period_bytes_max, "%ld"),
949 	FIELD_ENTRY(periods_min, "%d"),
950 	FIELD_ENTRY(periods_max, "%d"),
951 };
952 
953 static void dummy_proc_read(struct snd_info_entry *entry,
954 			    struct snd_info_buffer *buffer)
955 {
956 	struct snd_dummy *dummy = entry->private_data;
957 	int i;
958 
959 	for (i = 0; i < ARRAY_SIZE(fields); i++) {
960 		snd_iprintf(buffer, "%s ", fields[i].name);
961 		if (fields[i].size == sizeof(int))
962 			snd_iprintf(buffer, fields[i].format,
963 				*get_dummy_int_ptr(dummy, fields[i].offset));
964 		else
965 			snd_iprintf(buffer, fields[i].format,
966 				*get_dummy_ll_ptr(dummy, fields[i].offset));
967 		if (!strcmp(fields[i].name, "formats"))
968 			print_formats(dummy, buffer);
969 		else if (!strcmp(fields[i].name, "rates"))
970 			print_rates(dummy, buffer);
971 		snd_iprintf(buffer, "\n");
972 	}
973 }
974 
975 static void dummy_proc_write(struct snd_info_entry *entry,
976 			     struct snd_info_buffer *buffer)
977 {
978 	struct snd_dummy *dummy = entry->private_data;
979 	char line[64];
980 
981 	while (!snd_info_get_line(buffer, line, sizeof(line))) {
982 		char item[20];
983 		const char *ptr;
984 		unsigned long long val;
985 		int i;
986 
987 		ptr = snd_info_get_str(item, line, sizeof(item));
988 		for (i = 0; i < ARRAY_SIZE(fields); i++) {
989 			if (!strcmp(item, fields[i].name))
990 				break;
991 		}
992 		if (i >= ARRAY_SIZE(fields))
993 			continue;
994 		snd_info_get_str(item, ptr, sizeof(item));
995 		if (kstrtoull(item, 0, &val))
996 			continue;
997 		if (fields[i].size == sizeof(int))
998 			*get_dummy_int_ptr(dummy, fields[i].offset) = val;
999 		else
1000 			*get_dummy_ll_ptr(dummy, fields[i].offset) = val;
1001 	}
1002 }
1003 
1004 static void dummy_proc_init(struct snd_dummy *chip)
1005 {
1006 	snd_card_rw_proc_new(chip->card, "dummy_pcm", chip,
1007 			     dummy_proc_read, dummy_proc_write);
1008 }
1009 #else
1010 #define dummy_proc_init(x)
1011 #endif /* CONFIG_SND_DEBUG && CONFIG_SND_PROC_FS */
1012 
1013 static int snd_dummy_probe(struct platform_device *devptr)
1014 {
1015 	struct snd_card *card;
1016 	struct snd_dummy *dummy;
1017 	const struct dummy_model *m = NULL, **mdl;
1018 	int idx, err;
1019 	int dev = devptr->id;
1020 
1021 	err = snd_devm_card_new(&devptr->dev, index[dev], id[dev], THIS_MODULE,
1022 				sizeof(struct snd_dummy), &card);
1023 	if (err < 0)
1024 		return err;
1025 	dummy = card->private_data;
1026 	dummy->card = card;
1027 	for (mdl = dummy_models; *mdl && model[dev]; mdl++) {
1028 		if (strcmp(model[dev], (*mdl)->name) == 0) {
1029 			pr_info("snd-dummy: Using model '%s' for card %i\n",
1030 				(*mdl)->name, card->number);
1031 			m = dummy->model = *mdl;
1032 			break;
1033 		}
1034 	}
1035 	for (idx = 0; idx < MAX_PCM_DEVICES && idx < pcm_devs[dev]; idx++) {
1036 		if (pcm_substreams[dev] < 1)
1037 			pcm_substreams[dev] = 1;
1038 		if (pcm_substreams[dev] > MAX_PCM_SUBSTREAMS)
1039 			pcm_substreams[dev] = MAX_PCM_SUBSTREAMS;
1040 		err = snd_card_dummy_pcm(dummy, idx, pcm_substreams[dev]);
1041 		if (err < 0)
1042 			return err;
1043 	}
1044 
1045 	dummy->pcm_hw = dummy_pcm_hardware;
1046 	if (m) {
1047 		if (m->formats)
1048 			dummy->pcm_hw.formats = m->formats;
1049 		if (m->buffer_bytes_max)
1050 			dummy->pcm_hw.buffer_bytes_max = m->buffer_bytes_max;
1051 		if (m->period_bytes_min)
1052 			dummy->pcm_hw.period_bytes_min = m->period_bytes_min;
1053 		if (m->period_bytes_max)
1054 			dummy->pcm_hw.period_bytes_max = m->period_bytes_max;
1055 		if (m->periods_min)
1056 			dummy->pcm_hw.periods_min = m->periods_min;
1057 		if (m->periods_max)
1058 			dummy->pcm_hw.periods_max = m->periods_max;
1059 		if (m->rates)
1060 			dummy->pcm_hw.rates = m->rates;
1061 		if (m->rate_min)
1062 			dummy->pcm_hw.rate_min = m->rate_min;
1063 		if (m->rate_max)
1064 			dummy->pcm_hw.rate_max = m->rate_max;
1065 		if (m->channels_min)
1066 			dummy->pcm_hw.channels_min = m->channels_min;
1067 		if (m->channels_max)
1068 			dummy->pcm_hw.channels_max = m->channels_max;
1069 	}
1070 
1071 	if (mixer_volume_level_min > mixer_volume_level_max) {
1072 		pr_warn("snd-dummy: Invalid mixer volume level: min=%d, max=%d. Fall back to default value.\n",
1073 		mixer_volume_level_min, mixer_volume_level_max);
1074 		mixer_volume_level_min = USE_MIXER_VOLUME_LEVEL_MIN;
1075 		mixer_volume_level_max = USE_MIXER_VOLUME_LEVEL_MAX;
1076 	}
1077 	err = snd_card_dummy_new_mixer(dummy);
1078 	if (err < 0)
1079 		return err;
1080 	strscpy(card->driver, "Dummy");
1081 	strscpy(card->shortname, "Dummy");
1082 	sprintf(card->longname, "Dummy %i", dev + 1);
1083 
1084 	dummy_proc_init(dummy);
1085 
1086 	err = snd_card_register(card);
1087 	if (err < 0)
1088 		return err;
1089 	platform_set_drvdata(devptr, card);
1090 	return 0;
1091 }
1092 
1093 static int snd_dummy_suspend(struct device *pdev)
1094 {
1095 	struct snd_card *card = dev_get_drvdata(pdev);
1096 
1097 	snd_power_change_state(card, SNDRV_CTL_POWER_D3hot);
1098 	return 0;
1099 }
1100 
1101 static int snd_dummy_resume(struct device *pdev)
1102 {
1103 	struct snd_card *card = dev_get_drvdata(pdev);
1104 
1105 	snd_power_change_state(card, SNDRV_CTL_POWER_D0);
1106 	return 0;
1107 }
1108 
1109 static DEFINE_SIMPLE_DEV_PM_OPS(snd_dummy_pm, snd_dummy_suspend, snd_dummy_resume);
1110 
1111 #define SND_DUMMY_DRIVER	"snd_dummy"
1112 
1113 static struct platform_driver snd_dummy_driver = {
1114 	.probe		= snd_dummy_probe,
1115 	.driver		= {
1116 		.name	= SND_DUMMY_DRIVER,
1117 		.pm	= &snd_dummy_pm,
1118 	},
1119 };
1120 
1121 static void snd_dummy_unregister_all(void)
1122 {
1123 	int i;
1124 
1125 	for (i = 0; i < ARRAY_SIZE(devices); ++i)
1126 		platform_device_unregister(devices[i]);
1127 	platform_driver_unregister(&snd_dummy_driver);
1128 	free_fake_buffer();
1129 }
1130 
1131 static int __init alsa_card_dummy_init(void)
1132 {
1133 	int i, cards, err;
1134 
1135 	err = platform_driver_register(&snd_dummy_driver);
1136 	if (err < 0)
1137 		return err;
1138 
1139 	err = alloc_fake_buffer();
1140 	if (err < 0) {
1141 		platform_driver_unregister(&snd_dummy_driver);
1142 		return err;
1143 	}
1144 
1145 	cards = 0;
1146 	for (i = 0; i < SNDRV_CARDS; i++) {
1147 		struct platform_device *device;
1148 		if (! enable[i])
1149 			continue;
1150 		device = platform_device_register_simple(SND_DUMMY_DRIVER,
1151 							 i, NULL, 0);
1152 		if (IS_ERR(device))
1153 			continue;
1154 		if (!platform_get_drvdata(device)) {
1155 			platform_device_unregister(device);
1156 			continue;
1157 		}
1158 		devices[i] = device;
1159 		cards++;
1160 	}
1161 	if (!cards) {
1162 #ifdef MODULE
1163 		pr_err("Dummy soundcard not found or device busy\n");
1164 #endif
1165 		snd_dummy_unregister_all();
1166 		return -ENODEV;
1167 	}
1168 	return 0;
1169 }
1170 
1171 static void __exit alsa_card_dummy_exit(void)
1172 {
1173 	snd_dummy_unregister_all();
1174 }
1175 
1176 module_init(alsa_card_dummy_init)
1177 module_exit(alsa_card_dummy_exit)
1178