xref: /openbmc/linux/sound/drivers/aloop.c (revision f7efa9b8)
1 // SPDX-License-Identifier: GPL-2.0-or-later
2 /*
3  *  Loopback soundcard
4  *
5  *  Original code:
6  *  Copyright (c) by Jaroslav Kysela <perex@perex.cz>
7  *
8  *  More accurate positioning and full-duplex support:
9  *  Copyright (c) Ahmet İnan <ainan at mathematik.uni-freiburg.de>
10  *
11  *  Major (almost complete) rewrite:
12  *  Copyright (c) by Takashi Iwai <tiwai@suse.de>
13  *
14  *  A next major update in 2010 (separate timers for playback and capture):
15  *  Copyright (c) Jaroslav Kysela <perex@perex.cz>
16  */
17 
18 #include <linux/init.h>
19 #include <linux/jiffies.h>
20 #include <linux/slab.h>
21 #include <linux/time.h>
22 #include <linux/wait.h>
23 #include <linux/module.h>
24 #include <linux/platform_device.h>
25 #include <sound/core.h>
26 #include <sound/control.h>
27 #include <sound/pcm.h>
28 #include <sound/pcm_params.h>
29 #include <sound/info.h>
30 #include <sound/initval.h>
31 #include <sound/timer.h>
32 
33 MODULE_AUTHOR("Jaroslav Kysela <perex@perex.cz>");
34 MODULE_DESCRIPTION("A loopback soundcard");
35 MODULE_LICENSE("GPL");
36 
37 #define MAX_PCM_SUBSTREAMS	8
38 
39 static int index[SNDRV_CARDS] = SNDRV_DEFAULT_IDX;	/* Index 0-MAX */
40 static char *id[SNDRV_CARDS] = SNDRV_DEFAULT_STR;	/* ID for this card */
41 static bool enable[SNDRV_CARDS] = {1, [1 ... (SNDRV_CARDS - 1)] = 0};
42 static int pcm_substreams[SNDRV_CARDS] = {[0 ... (SNDRV_CARDS - 1)] = 8};
43 static int pcm_notify[SNDRV_CARDS];
44 static char *timer_source[SNDRV_CARDS];
45 
46 module_param_array(index, int, NULL, 0444);
47 MODULE_PARM_DESC(index, "Index value for loopback soundcard.");
48 module_param_array(id, charp, NULL, 0444);
49 MODULE_PARM_DESC(id, "ID string for loopback soundcard.");
50 module_param_array(enable, bool, NULL, 0444);
51 MODULE_PARM_DESC(enable, "Enable this loopback soundcard.");
52 module_param_array(pcm_substreams, int, NULL, 0444);
53 MODULE_PARM_DESC(pcm_substreams, "PCM substreams # (1-8) for loopback driver.");
54 module_param_array(pcm_notify, int, NULL, 0444);
55 MODULE_PARM_DESC(pcm_notify, "Break capture when PCM format/rate/channels changes.");
56 module_param_array(timer_source, charp, NULL, 0444);
57 MODULE_PARM_DESC(timer_source, "Sound card name or number and device/subdevice number of timer to be used. Empty string for jiffies timer [default].");
58 
59 #define NO_PITCH 100000
60 
61 #define CABLE_VALID_PLAYBACK	BIT(SNDRV_PCM_STREAM_PLAYBACK)
62 #define CABLE_VALID_CAPTURE	BIT(SNDRV_PCM_STREAM_CAPTURE)
63 #define CABLE_VALID_BOTH	(CABLE_VALID_PLAYBACK | CABLE_VALID_CAPTURE)
64 
65 struct loopback_cable;
66 struct loopback_pcm;
67 
68 struct loopback_ops {
69 	/* optional
70 	 * call in loopback->cable_lock
71 	 */
72 	int (*open)(struct loopback_pcm *dpcm);
73 	/* required
74 	 * call in cable->lock
75 	 */
76 	int (*start)(struct loopback_pcm *dpcm);
77 	/* required
78 	 * call in cable->lock
79 	 */
80 	int (*stop)(struct loopback_pcm *dpcm);
81 	/* optional */
82 	int (*stop_sync)(struct loopback_pcm *dpcm);
83 	/* optional */
84 	int (*close_substream)(struct loopback_pcm *dpcm);
85 	/* optional
86 	 * call in loopback->cable_lock
87 	 */
88 	int (*close_cable)(struct loopback_pcm *dpcm);
89 	/* optional
90 	 * call in cable->lock
91 	 */
92 	unsigned int (*pos_update)(struct loopback_cable *cable);
93 	/* optional */
94 	void (*dpcm_info)(struct loopback_pcm *dpcm,
95 			  struct snd_info_buffer *buffer);
96 };
97 
98 struct loopback_cable {
99 	spinlock_t lock;
100 	struct loopback_pcm *streams[2];
101 	struct snd_pcm_hardware hw;
102 	/* flags */
103 	unsigned int valid;
104 	unsigned int running;
105 	unsigned int pause;
106 	/* timer specific */
107 	const struct loopback_ops *ops;
108 	/* If sound timer is used */
109 	struct {
110 		int stream;
111 		struct snd_timer_id id;
112 		struct work_struct event_work;
113 		struct snd_timer_instance *instance;
114 	} snd_timer;
115 };
116 
117 struct loopback_setup {
118 	unsigned int notify: 1;
119 	unsigned int rate_shift;
120 	snd_pcm_format_t format;
121 	unsigned int rate;
122 	unsigned int channels;
123 	struct snd_ctl_elem_id active_id;
124 	struct snd_ctl_elem_id format_id;
125 	struct snd_ctl_elem_id rate_id;
126 	struct snd_ctl_elem_id channels_id;
127 };
128 
129 struct loopback {
130 	struct snd_card *card;
131 	struct mutex cable_lock;
132 	struct loopback_cable *cables[MAX_PCM_SUBSTREAMS][2];
133 	struct snd_pcm *pcm[2];
134 	struct loopback_setup setup[MAX_PCM_SUBSTREAMS][2];
135 	const char *timer_source;
136 };
137 
138 struct loopback_pcm {
139 	struct loopback *loopback;
140 	struct snd_pcm_substream *substream;
141 	struct loopback_cable *cable;
142 	unsigned int pcm_buffer_size;
143 	unsigned int buf_pos;	/* position in buffer */
144 	unsigned int silent_size;
145 	/* PCM parameters */
146 	unsigned int pcm_period_size;
147 	unsigned int pcm_bps;		/* bytes per second */
148 	unsigned int pcm_salign;	/* bytes per sample * channels */
149 	unsigned int pcm_rate_shift;	/* rate shift value */
150 	/* flags */
151 	unsigned int period_update_pending :1;
152 	/* timer stuff */
153 	unsigned int irq_pos;		/* fractional IRQ position in jiffies
154 					 * ticks
155 					 */
156 	unsigned int period_size_frac;	/* period size in jiffies ticks */
157 	unsigned int last_drift;
158 	unsigned long last_jiffies;
159 	/* If jiffies timer is used */
160 	struct timer_list timer;
161 };
162 
163 static struct platform_device *devices[SNDRV_CARDS];
164 
byte_pos(struct loopback_pcm * dpcm,unsigned int x)165 static inline unsigned int byte_pos(struct loopback_pcm *dpcm, unsigned int x)
166 {
167 	if (dpcm->pcm_rate_shift == NO_PITCH) {
168 		x /= HZ;
169 	} else {
170 		x = div_u64(NO_PITCH * (unsigned long long)x,
171 			    HZ * (unsigned long long)dpcm->pcm_rate_shift);
172 	}
173 	return x - (x % dpcm->pcm_salign);
174 }
175 
frac_pos(struct loopback_pcm * dpcm,unsigned int x)176 static inline unsigned int frac_pos(struct loopback_pcm *dpcm, unsigned int x)
177 {
178 	if (dpcm->pcm_rate_shift == NO_PITCH) {	/* no pitch */
179 		return x * HZ;
180 	} else {
181 		x = div_u64(dpcm->pcm_rate_shift * (unsigned long long)x * HZ,
182 			    NO_PITCH);
183 	}
184 	return x;
185 }
186 
get_setup(struct loopback_pcm * dpcm)187 static inline struct loopback_setup *get_setup(struct loopback_pcm *dpcm)
188 {
189 	int device = dpcm->substream->pstr->pcm->device;
190 
191 	if (dpcm->substream->stream == SNDRV_PCM_STREAM_PLAYBACK)
192 		device ^= 1;
193 	return &dpcm->loopback->setup[dpcm->substream->number][device];
194 }
195 
get_notify(struct loopback_pcm * dpcm)196 static inline unsigned int get_notify(struct loopback_pcm *dpcm)
197 {
198 	return get_setup(dpcm)->notify;
199 }
200 
get_rate_shift(struct loopback_pcm * dpcm)201 static inline unsigned int get_rate_shift(struct loopback_pcm *dpcm)
202 {
203 	return get_setup(dpcm)->rate_shift;
204 }
205 
206 /* call in cable->lock */
loopback_jiffies_timer_start(struct loopback_pcm * dpcm)207 static int loopback_jiffies_timer_start(struct loopback_pcm *dpcm)
208 {
209 	unsigned long tick;
210 	unsigned int rate_shift = get_rate_shift(dpcm);
211 
212 	if (rate_shift != dpcm->pcm_rate_shift) {
213 		dpcm->pcm_rate_shift = rate_shift;
214 		dpcm->period_size_frac = frac_pos(dpcm, dpcm->pcm_period_size);
215 	}
216 	if (dpcm->period_size_frac <= dpcm->irq_pos) {
217 		dpcm->irq_pos %= dpcm->period_size_frac;
218 		dpcm->period_update_pending = 1;
219 	}
220 	tick = dpcm->period_size_frac - dpcm->irq_pos;
221 	tick = DIV_ROUND_UP(tick, dpcm->pcm_bps);
222 	mod_timer(&dpcm->timer, jiffies + tick);
223 
224 	return 0;
225 }
226 
227 /* call in cable->lock */
loopback_snd_timer_start(struct loopback_pcm * dpcm)228 static int loopback_snd_timer_start(struct loopback_pcm *dpcm)
229 {
230 	struct loopback_cable *cable = dpcm->cable;
231 	int err;
232 
233 	/* Loopback device has to use same period as timer card. Therefore
234 	 * wake up for each snd_pcm_period_elapsed() call of timer card.
235 	 */
236 	err = snd_timer_start(cable->snd_timer.instance, 1);
237 	if (err < 0) {
238 		/* do not report error if trying to start but already
239 		 * running. For example called by opposite substream
240 		 * of the same cable
241 		 */
242 		if (err == -EBUSY)
243 			return 0;
244 
245 		pcm_err(dpcm->substream->pcm,
246 			"snd_timer_start(%d,%d,%d) failed with %d",
247 			cable->snd_timer.id.card,
248 			cable->snd_timer.id.device,
249 			cable->snd_timer.id.subdevice,
250 			err);
251 	}
252 
253 	return err;
254 }
255 
256 /* call in cable->lock */
loopback_jiffies_timer_stop(struct loopback_pcm * dpcm)257 static inline int loopback_jiffies_timer_stop(struct loopback_pcm *dpcm)
258 {
259 	del_timer(&dpcm->timer);
260 	dpcm->timer.expires = 0;
261 
262 	return 0;
263 }
264 
265 /* call in cable->lock */
loopback_snd_timer_stop(struct loopback_pcm * dpcm)266 static int loopback_snd_timer_stop(struct loopback_pcm *dpcm)
267 {
268 	struct loopback_cable *cable = dpcm->cable;
269 	int err;
270 
271 	/* only stop if both devices (playback and capture) are not running */
272 	if (cable->running ^ cable->pause)
273 		return 0;
274 
275 	err = snd_timer_stop(cable->snd_timer.instance);
276 	if (err < 0) {
277 		pcm_err(dpcm->substream->pcm,
278 			"snd_timer_stop(%d,%d,%d) failed with %d",
279 			cable->snd_timer.id.card,
280 			cable->snd_timer.id.device,
281 			cable->snd_timer.id.subdevice,
282 			err);
283 	}
284 
285 	return err;
286 }
287 
loopback_jiffies_timer_stop_sync(struct loopback_pcm * dpcm)288 static inline int loopback_jiffies_timer_stop_sync(struct loopback_pcm *dpcm)
289 {
290 	del_timer_sync(&dpcm->timer);
291 
292 	return 0;
293 }
294 
295 /* call in loopback->cable_lock */
loopback_snd_timer_close_cable(struct loopback_pcm * dpcm)296 static int loopback_snd_timer_close_cable(struct loopback_pcm *dpcm)
297 {
298 	struct loopback_cable *cable = dpcm->cable;
299 
300 	/* snd_timer was not opened */
301 	if (!cable->snd_timer.instance)
302 		return 0;
303 
304 	/* will only be called from free_cable() when other stream was
305 	 * already closed. Other stream cannot be reopened as long as
306 	 * loopback->cable_lock is locked. Therefore no need to lock
307 	 * cable->lock;
308 	 */
309 	snd_timer_close(cable->snd_timer.instance);
310 
311 	/* wait till drain work has finished if requested */
312 	cancel_work_sync(&cable->snd_timer.event_work);
313 
314 	snd_timer_instance_free(cable->snd_timer.instance);
315 	memset(&cable->snd_timer, 0, sizeof(cable->snd_timer));
316 
317 	return 0;
318 }
319 
loopback_check_format(struct loopback_cable * cable,int stream)320 static int loopback_check_format(struct loopback_cable *cable, int stream)
321 {
322 	struct snd_pcm_runtime *runtime, *cruntime;
323 	struct loopback_setup *setup;
324 	struct snd_card *card;
325 	int check;
326 
327 	if (cable->valid != CABLE_VALID_BOTH) {
328 		if (stream == SNDRV_PCM_STREAM_PLAYBACK)
329 			goto __notify;
330 		return 0;
331 	}
332 	runtime = cable->streams[SNDRV_PCM_STREAM_PLAYBACK]->
333 							substream->runtime;
334 	cruntime = cable->streams[SNDRV_PCM_STREAM_CAPTURE]->
335 							substream->runtime;
336 	check = runtime->format != cruntime->format ||
337 		runtime->rate != cruntime->rate ||
338 		runtime->channels != cruntime->channels;
339 	if (!check)
340 		return 0;
341 	if (stream == SNDRV_PCM_STREAM_CAPTURE) {
342 		return -EIO;
343 	} else {
344 		snd_pcm_stop(cable->streams[SNDRV_PCM_STREAM_CAPTURE]->
345 					substream, SNDRV_PCM_STATE_DRAINING);
346 	      __notify:
347 		runtime = cable->streams[SNDRV_PCM_STREAM_PLAYBACK]->
348 							substream->runtime;
349 		setup = get_setup(cable->streams[SNDRV_PCM_STREAM_PLAYBACK]);
350 		card = cable->streams[SNDRV_PCM_STREAM_PLAYBACK]->loopback->card;
351 		if (setup->format != runtime->format) {
352 			snd_ctl_notify(card, SNDRV_CTL_EVENT_MASK_VALUE,
353 							&setup->format_id);
354 			setup->format = runtime->format;
355 		}
356 		if (setup->rate != runtime->rate) {
357 			snd_ctl_notify(card, SNDRV_CTL_EVENT_MASK_VALUE,
358 							&setup->rate_id);
359 			setup->rate = runtime->rate;
360 		}
361 		if (setup->channels != runtime->channels) {
362 			snd_ctl_notify(card, SNDRV_CTL_EVENT_MASK_VALUE,
363 							&setup->channels_id);
364 			setup->channels = runtime->channels;
365 		}
366 	}
367 	return 0;
368 }
369 
loopback_active_notify(struct loopback_pcm * dpcm)370 static void loopback_active_notify(struct loopback_pcm *dpcm)
371 {
372 	snd_ctl_notify(dpcm->loopback->card,
373 		       SNDRV_CTL_EVENT_MASK_VALUE,
374 		       &get_setup(dpcm)->active_id);
375 }
376 
loopback_trigger(struct snd_pcm_substream * substream,int cmd)377 static int loopback_trigger(struct snd_pcm_substream *substream, int cmd)
378 {
379 	struct snd_pcm_runtime *runtime = substream->runtime;
380 	struct loopback_pcm *dpcm = runtime->private_data;
381 	struct loopback_cable *cable = dpcm->cable;
382 	int err = 0, stream = 1 << substream->stream;
383 
384 	switch (cmd) {
385 	case SNDRV_PCM_TRIGGER_START:
386 		err = loopback_check_format(cable, substream->stream);
387 		if (err < 0)
388 			return err;
389 		dpcm->last_jiffies = jiffies;
390 		dpcm->pcm_rate_shift = 0;
391 		dpcm->last_drift = 0;
392 		spin_lock(&cable->lock);
393 		cable->running |= stream;
394 		cable->pause &= ~stream;
395 		err = cable->ops->start(dpcm);
396 		spin_unlock(&cable->lock);
397 		if (substream->stream == SNDRV_PCM_STREAM_PLAYBACK)
398 			loopback_active_notify(dpcm);
399 		break;
400 	case SNDRV_PCM_TRIGGER_STOP:
401 		spin_lock(&cable->lock);
402 		cable->running &= ~stream;
403 		cable->pause &= ~stream;
404 		err = cable->ops->stop(dpcm);
405 		spin_unlock(&cable->lock);
406 		if (substream->stream == SNDRV_PCM_STREAM_PLAYBACK)
407 			loopback_active_notify(dpcm);
408 		break;
409 	case SNDRV_PCM_TRIGGER_PAUSE_PUSH:
410 	case SNDRV_PCM_TRIGGER_SUSPEND:
411 		spin_lock(&cable->lock);
412 		cable->pause |= stream;
413 		err = cable->ops->stop(dpcm);
414 		spin_unlock(&cable->lock);
415 		if (substream->stream == SNDRV_PCM_STREAM_PLAYBACK)
416 			loopback_active_notify(dpcm);
417 		break;
418 	case SNDRV_PCM_TRIGGER_PAUSE_RELEASE:
419 	case SNDRV_PCM_TRIGGER_RESUME:
420 		spin_lock(&cable->lock);
421 		dpcm->last_jiffies = jiffies;
422 		cable->pause &= ~stream;
423 		err = cable->ops->start(dpcm);
424 		spin_unlock(&cable->lock);
425 		if (substream->stream == SNDRV_PCM_STREAM_PLAYBACK)
426 			loopback_active_notify(dpcm);
427 		break;
428 	default:
429 		return -EINVAL;
430 	}
431 	return err;
432 }
433 
params_change(struct snd_pcm_substream * substream)434 static void params_change(struct snd_pcm_substream *substream)
435 {
436 	struct snd_pcm_runtime *runtime = substream->runtime;
437 	struct loopback_pcm *dpcm = runtime->private_data;
438 	struct loopback_cable *cable = dpcm->cable;
439 
440 	cable->hw.formats = pcm_format_to_bits(runtime->format);
441 	cable->hw.rate_min = runtime->rate;
442 	cable->hw.rate_max = runtime->rate;
443 	cable->hw.channels_min = runtime->channels;
444 	cable->hw.channels_max = runtime->channels;
445 
446 	if (cable->snd_timer.instance) {
447 		cable->hw.period_bytes_min =
448 				frames_to_bytes(runtime, runtime->period_size);
449 		cable->hw.period_bytes_max = cable->hw.period_bytes_min;
450 	}
451 
452 }
453 
loopback_prepare(struct snd_pcm_substream * substream)454 static int loopback_prepare(struct snd_pcm_substream *substream)
455 {
456 	struct snd_pcm_runtime *runtime = substream->runtime;
457 	struct loopback_pcm *dpcm = runtime->private_data;
458 	struct loopback_cable *cable = dpcm->cable;
459 	int err, bps, salign;
460 
461 	if (cable->ops->stop_sync) {
462 		err = cable->ops->stop_sync(dpcm);
463 		if (err < 0)
464 			return err;
465 	}
466 
467 	salign = (snd_pcm_format_physical_width(runtime->format) *
468 						runtime->channels) / 8;
469 	bps = salign * runtime->rate;
470 	if (bps <= 0 || salign <= 0)
471 		return -EINVAL;
472 
473 	dpcm->buf_pos = 0;
474 	dpcm->pcm_buffer_size = frames_to_bytes(runtime, runtime->buffer_size);
475 	if (substream->stream == SNDRV_PCM_STREAM_CAPTURE) {
476 		/* clear capture buffer */
477 		dpcm->silent_size = dpcm->pcm_buffer_size;
478 		snd_pcm_format_set_silence(runtime->format, runtime->dma_area,
479 					   runtime->buffer_size * runtime->channels);
480 	}
481 
482 	dpcm->irq_pos = 0;
483 	dpcm->period_update_pending = 0;
484 	dpcm->pcm_bps = bps;
485 	dpcm->pcm_salign = salign;
486 	dpcm->pcm_period_size = frames_to_bytes(runtime, runtime->period_size);
487 
488 	mutex_lock(&dpcm->loopback->cable_lock);
489 	if (!(cable->valid & ~(1 << substream->stream)) ||
490             (get_setup(dpcm)->notify &&
491 	     substream->stream == SNDRV_PCM_STREAM_PLAYBACK))
492 		params_change(substream);
493 	cable->valid |= 1 << substream->stream;
494 	mutex_unlock(&dpcm->loopback->cable_lock);
495 
496 	return 0;
497 }
498 
clear_capture_buf(struct loopback_pcm * dpcm,unsigned int bytes)499 static void clear_capture_buf(struct loopback_pcm *dpcm, unsigned int bytes)
500 {
501 	struct snd_pcm_runtime *runtime = dpcm->substream->runtime;
502 	char *dst = runtime->dma_area;
503 	unsigned int dst_off = dpcm->buf_pos;
504 
505 	if (dpcm->silent_size >= dpcm->pcm_buffer_size)
506 		return;
507 	if (dpcm->silent_size + bytes > dpcm->pcm_buffer_size)
508 		bytes = dpcm->pcm_buffer_size - dpcm->silent_size;
509 
510 	for (;;) {
511 		unsigned int size = bytes;
512 		if (dst_off + size > dpcm->pcm_buffer_size)
513 			size = dpcm->pcm_buffer_size - dst_off;
514 		snd_pcm_format_set_silence(runtime->format, dst + dst_off,
515 					   bytes_to_frames(runtime, size) *
516 					   	runtime->channels);
517 		dpcm->silent_size += size;
518 		bytes -= size;
519 		if (!bytes)
520 			break;
521 		dst_off = 0;
522 	}
523 }
524 
copy_play_buf(struct loopback_pcm * play,struct loopback_pcm * capt,unsigned int bytes)525 static void copy_play_buf(struct loopback_pcm *play,
526 			  struct loopback_pcm *capt,
527 			  unsigned int bytes)
528 {
529 	struct snd_pcm_runtime *runtime = play->substream->runtime;
530 	char *src = runtime->dma_area;
531 	char *dst = capt->substream->runtime->dma_area;
532 	unsigned int src_off = play->buf_pos;
533 	unsigned int dst_off = capt->buf_pos;
534 	unsigned int clear_bytes = 0;
535 
536 	/* check if playback is draining, trim the capture copy size
537 	 * when our pointer is at the end of playback ring buffer */
538 	if (runtime->state == SNDRV_PCM_STATE_DRAINING &&
539 	    snd_pcm_playback_hw_avail(runtime) < runtime->buffer_size) {
540 	    	snd_pcm_uframes_t appl_ptr, appl_ptr1, diff;
541 		appl_ptr = appl_ptr1 = runtime->control->appl_ptr;
542 		appl_ptr1 -= appl_ptr1 % runtime->buffer_size;
543 		appl_ptr1 += play->buf_pos / play->pcm_salign;
544 		if (appl_ptr < appl_ptr1)
545 			appl_ptr1 -= runtime->buffer_size;
546 		diff = (appl_ptr - appl_ptr1) * play->pcm_salign;
547 		if (diff < bytes) {
548 			clear_bytes = bytes - diff;
549 			bytes = diff;
550 		}
551 	}
552 
553 	for (;;) {
554 		unsigned int size = bytes;
555 		if (src_off + size > play->pcm_buffer_size)
556 			size = play->pcm_buffer_size - src_off;
557 		if (dst_off + size > capt->pcm_buffer_size)
558 			size = capt->pcm_buffer_size - dst_off;
559 		memcpy(dst + dst_off, src + src_off, size);
560 		capt->silent_size = 0;
561 		bytes -= size;
562 		if (!bytes)
563 			break;
564 		src_off = (src_off + size) % play->pcm_buffer_size;
565 		dst_off = (dst_off + size) % capt->pcm_buffer_size;
566 	}
567 
568 	if (clear_bytes > 0) {
569 		clear_capture_buf(capt, clear_bytes);
570 		capt->silent_size = 0;
571 	}
572 }
573 
bytepos_delta(struct loopback_pcm * dpcm,unsigned int jiffies_delta)574 static inline unsigned int bytepos_delta(struct loopback_pcm *dpcm,
575 					 unsigned int jiffies_delta)
576 {
577 	unsigned long last_pos;
578 	unsigned int delta;
579 
580 	last_pos = byte_pos(dpcm, dpcm->irq_pos);
581 	dpcm->irq_pos += jiffies_delta * dpcm->pcm_bps;
582 	delta = byte_pos(dpcm, dpcm->irq_pos) - last_pos;
583 	if (delta >= dpcm->last_drift)
584 		delta -= dpcm->last_drift;
585 	dpcm->last_drift = 0;
586 	if (dpcm->irq_pos >= dpcm->period_size_frac) {
587 		dpcm->irq_pos %= dpcm->period_size_frac;
588 		dpcm->period_update_pending = 1;
589 	}
590 	return delta;
591 }
592 
bytepos_finish(struct loopback_pcm * dpcm,unsigned int delta)593 static inline void bytepos_finish(struct loopback_pcm *dpcm,
594 				  unsigned int delta)
595 {
596 	dpcm->buf_pos += delta;
597 	dpcm->buf_pos %= dpcm->pcm_buffer_size;
598 }
599 
600 /* call in cable->lock */
loopback_jiffies_timer_pos_update(struct loopback_cable * cable)601 static unsigned int loopback_jiffies_timer_pos_update
602 		(struct loopback_cable *cable)
603 {
604 	struct loopback_pcm *dpcm_play =
605 			cable->streams[SNDRV_PCM_STREAM_PLAYBACK];
606 	struct loopback_pcm *dpcm_capt =
607 			cable->streams[SNDRV_PCM_STREAM_CAPTURE];
608 	unsigned long delta_play = 0, delta_capt = 0, cur_jiffies;
609 	unsigned int running, count1, count2;
610 
611 	cur_jiffies = jiffies;
612 	running = cable->running ^ cable->pause;
613 	if (running & (1 << SNDRV_PCM_STREAM_PLAYBACK)) {
614 		delta_play = cur_jiffies - dpcm_play->last_jiffies;
615 		dpcm_play->last_jiffies += delta_play;
616 	}
617 
618 	if (running & (1 << SNDRV_PCM_STREAM_CAPTURE)) {
619 		delta_capt = cur_jiffies - dpcm_capt->last_jiffies;
620 		dpcm_capt->last_jiffies += delta_capt;
621 	}
622 
623 	if (delta_play == 0 && delta_capt == 0)
624 		goto unlock;
625 
626 	if (delta_play > delta_capt) {
627 		count1 = bytepos_delta(dpcm_play, delta_play - delta_capt);
628 		bytepos_finish(dpcm_play, count1);
629 		delta_play = delta_capt;
630 	} else if (delta_play < delta_capt) {
631 		count1 = bytepos_delta(dpcm_capt, delta_capt - delta_play);
632 		clear_capture_buf(dpcm_capt, count1);
633 		bytepos_finish(dpcm_capt, count1);
634 		delta_capt = delta_play;
635 	}
636 
637 	if (delta_play == 0 && delta_capt == 0)
638 		goto unlock;
639 
640 	/* note delta_capt == delta_play at this moment */
641 	count1 = bytepos_delta(dpcm_play, delta_play);
642 	count2 = bytepos_delta(dpcm_capt, delta_capt);
643 	if (count1 < count2) {
644 		dpcm_capt->last_drift = count2 - count1;
645 		count1 = count2;
646 	} else if (count1 > count2) {
647 		dpcm_play->last_drift = count1 - count2;
648 	}
649 	copy_play_buf(dpcm_play, dpcm_capt, count1);
650 	bytepos_finish(dpcm_play, count1);
651 	bytepos_finish(dpcm_capt, count1);
652  unlock:
653 	return running;
654 }
655 
loopback_jiffies_timer_function(struct timer_list * t)656 static void loopback_jiffies_timer_function(struct timer_list *t)
657 {
658 	struct loopback_pcm *dpcm = from_timer(dpcm, t, timer);
659 	unsigned long flags;
660 
661 	spin_lock_irqsave(&dpcm->cable->lock, flags);
662 	if (loopback_jiffies_timer_pos_update(dpcm->cable) &
663 			(1 << dpcm->substream->stream)) {
664 		loopback_jiffies_timer_start(dpcm);
665 		if (dpcm->period_update_pending) {
666 			dpcm->period_update_pending = 0;
667 			spin_unlock_irqrestore(&dpcm->cable->lock, flags);
668 			/* need to unlock before calling below */
669 			snd_pcm_period_elapsed(dpcm->substream);
670 			return;
671 		}
672 	}
673 	spin_unlock_irqrestore(&dpcm->cable->lock, flags);
674 }
675 
676 /* call in cable->lock */
loopback_snd_timer_check_resolution(struct snd_pcm_runtime * runtime,unsigned long resolution)677 static int loopback_snd_timer_check_resolution(struct snd_pcm_runtime *runtime,
678 					       unsigned long resolution)
679 {
680 	if (resolution != runtime->timer_resolution) {
681 		struct loopback_pcm *dpcm = runtime->private_data;
682 		struct loopback_cable *cable = dpcm->cable;
683 		/* Worst case estimation of possible values for resolution
684 		 * resolution <= (512 * 1024) frames / 8kHz in nsec
685 		 * resolution <= 65.536.000.000 nsec
686 		 *
687 		 * period_size <= 65.536.000.000 nsec / 1000nsec/usec * 192kHz +
688 		 *  500.000
689 		 * period_size <= 12.582.912.000.000  <64bit
690 		 *  / 1.000.000 usec/sec
691 		 */
692 		snd_pcm_uframes_t period_size_usec =
693 				resolution / 1000 * runtime->rate;
694 		/* round to nearest sample rate */
695 		snd_pcm_uframes_t period_size =
696 				(period_size_usec + 500 * 1000) / (1000 * 1000);
697 
698 		pcm_err(dpcm->substream->pcm,
699 			"Period size (%lu frames) of loopback device is not corresponding to timer resolution (%lu nsec = %lu frames) of card timer %d,%d,%d. Use period size of %lu frames for loopback device.",
700 			runtime->period_size, resolution, period_size,
701 			cable->snd_timer.id.card,
702 			cable->snd_timer.id.device,
703 			cable->snd_timer.id.subdevice,
704 			period_size);
705 		return -EINVAL;
706 	}
707 	return 0;
708 }
709 
loopback_snd_timer_period_elapsed(struct loopback_cable * cable,int event,unsigned long resolution)710 static void loopback_snd_timer_period_elapsed(struct loopback_cable *cable,
711 					      int event,
712 					      unsigned long resolution)
713 {
714 	struct loopback_pcm *dpcm_play, *dpcm_capt;
715 	struct snd_pcm_substream *substream_play, *substream_capt;
716 	struct snd_pcm_runtime *valid_runtime;
717 	unsigned int running, elapsed_bytes;
718 	unsigned long flags;
719 
720 	spin_lock_irqsave(&cable->lock, flags);
721 	running = cable->running ^ cable->pause;
722 	/* no need to do anything if no stream is running */
723 	if (!running) {
724 		spin_unlock_irqrestore(&cable->lock, flags);
725 		return;
726 	}
727 
728 	dpcm_play = cable->streams[SNDRV_PCM_STREAM_PLAYBACK];
729 	dpcm_capt = cable->streams[SNDRV_PCM_STREAM_CAPTURE];
730 
731 	if (event == SNDRV_TIMER_EVENT_MSTOP) {
732 		if (!dpcm_play ||
733 		    dpcm_play->substream->runtime->state !=
734 				SNDRV_PCM_STATE_DRAINING) {
735 			spin_unlock_irqrestore(&cable->lock, flags);
736 			return;
737 		}
738 	}
739 
740 	substream_play = (running & (1 << SNDRV_PCM_STREAM_PLAYBACK)) ?
741 			dpcm_play->substream : NULL;
742 	substream_capt = (running & (1 << SNDRV_PCM_STREAM_CAPTURE)) ?
743 			dpcm_capt->substream : NULL;
744 	valid_runtime = (running & (1 << SNDRV_PCM_STREAM_PLAYBACK)) ?
745 				dpcm_play->substream->runtime :
746 				dpcm_capt->substream->runtime;
747 
748 	/* resolution is only valid for SNDRV_TIMER_EVENT_TICK events */
749 	if (event == SNDRV_TIMER_EVENT_TICK) {
750 		/* The hardware rules guarantee that playback and capture period
751 		 * are the same. Therefore only one device has to be checked
752 		 * here.
753 		 */
754 		if (loopback_snd_timer_check_resolution(valid_runtime,
755 							resolution) < 0) {
756 			spin_unlock_irqrestore(&cable->lock, flags);
757 			if (substream_play)
758 				snd_pcm_stop_xrun(substream_play);
759 			if (substream_capt)
760 				snd_pcm_stop_xrun(substream_capt);
761 			return;
762 		}
763 	}
764 
765 	elapsed_bytes = frames_to_bytes(valid_runtime,
766 					valid_runtime->period_size);
767 	/* The same timer interrupt is used for playback and capture device */
768 	if ((running & (1 << SNDRV_PCM_STREAM_PLAYBACK)) &&
769 	    (running & (1 << SNDRV_PCM_STREAM_CAPTURE))) {
770 		copy_play_buf(dpcm_play, dpcm_capt, elapsed_bytes);
771 		bytepos_finish(dpcm_play, elapsed_bytes);
772 		bytepos_finish(dpcm_capt, elapsed_bytes);
773 	} else if (running & (1 << SNDRV_PCM_STREAM_PLAYBACK)) {
774 		bytepos_finish(dpcm_play, elapsed_bytes);
775 	} else if (running & (1 << SNDRV_PCM_STREAM_CAPTURE)) {
776 		clear_capture_buf(dpcm_capt, elapsed_bytes);
777 		bytepos_finish(dpcm_capt, elapsed_bytes);
778 	}
779 	spin_unlock_irqrestore(&cable->lock, flags);
780 
781 	if (substream_play)
782 		snd_pcm_period_elapsed(substream_play);
783 	if (substream_capt)
784 		snd_pcm_period_elapsed(substream_capt);
785 }
786 
loopback_snd_timer_function(struct snd_timer_instance * timeri,unsigned long resolution,unsigned long ticks)787 static void loopback_snd_timer_function(struct snd_timer_instance *timeri,
788 					unsigned long resolution,
789 					unsigned long ticks)
790 {
791 	struct loopback_cable *cable = timeri->callback_data;
792 
793 	loopback_snd_timer_period_elapsed(cable, SNDRV_TIMER_EVENT_TICK,
794 					  resolution);
795 }
796 
loopback_snd_timer_work(struct work_struct * work)797 static void loopback_snd_timer_work(struct work_struct *work)
798 {
799 	struct loopback_cable *cable;
800 
801 	cable = container_of(work, struct loopback_cable, snd_timer.event_work);
802 	loopback_snd_timer_period_elapsed(cable, SNDRV_TIMER_EVENT_MSTOP, 0);
803 }
804 
loopback_snd_timer_event(struct snd_timer_instance * timeri,int event,struct timespec64 * tstamp,unsigned long resolution)805 static void loopback_snd_timer_event(struct snd_timer_instance *timeri,
806 				     int event,
807 				     struct timespec64 *tstamp,
808 				     unsigned long resolution)
809 {
810 	/* Do not lock cable->lock here because timer->lock is already hold.
811 	 * There are other functions which first lock cable->lock and than
812 	 * timer->lock e.g.
813 	 * loopback_trigger()
814 	 * spin_lock(&cable->lock)
815 	 * loopback_snd_timer_start()
816 	 * snd_timer_start()
817 	 * spin_lock(&timer->lock)
818 	 * Therefore when using the oposit order of locks here it could result
819 	 * in a deadlock.
820 	 */
821 
822 	if (event == SNDRV_TIMER_EVENT_MSTOP) {
823 		struct loopback_cable *cable = timeri->callback_data;
824 
825 		/* sound card of the timer was stopped. Therefore there will not
826 		 * be any further timer callbacks. Due to this forward audio
827 		 * data from here if in draining state. When still in running
828 		 * state the streaming will be aborted by the usual timeout. It
829 		 * should not be aborted here because may be the timer sound
830 		 * card does only a recovery and the timer is back soon.
831 		 * This work triggers loopback_snd_timer_work()
832 		 */
833 		schedule_work(&cable->snd_timer.event_work);
834 	}
835 }
836 
loopback_jiffies_timer_dpcm_info(struct loopback_pcm * dpcm,struct snd_info_buffer * buffer)837 static void loopback_jiffies_timer_dpcm_info(struct loopback_pcm *dpcm,
838 					     struct snd_info_buffer *buffer)
839 {
840 	snd_iprintf(buffer, "    update_pending:\t%u\n",
841 		    dpcm->period_update_pending);
842 	snd_iprintf(buffer, "    irq_pos:\t\t%u\n", dpcm->irq_pos);
843 	snd_iprintf(buffer, "    period_frac:\t%u\n", dpcm->period_size_frac);
844 	snd_iprintf(buffer, "    last_jiffies:\t%lu (%lu)\n",
845 		    dpcm->last_jiffies, jiffies);
846 	snd_iprintf(buffer, "    timer_expires:\t%lu\n", dpcm->timer.expires);
847 }
848 
loopback_snd_timer_dpcm_info(struct loopback_pcm * dpcm,struct snd_info_buffer * buffer)849 static void loopback_snd_timer_dpcm_info(struct loopback_pcm *dpcm,
850 					 struct snd_info_buffer *buffer)
851 {
852 	struct loopback_cable *cable = dpcm->cable;
853 
854 	snd_iprintf(buffer, "    sound timer:\thw:%d,%d,%d\n",
855 		    cable->snd_timer.id.card,
856 		    cable->snd_timer.id.device,
857 		    cable->snd_timer.id.subdevice);
858 	snd_iprintf(buffer, "    timer open:\t\t%s\n",
859 		    (cable->snd_timer.stream == SNDRV_PCM_STREAM_CAPTURE) ?
860 			    "capture" : "playback");
861 }
862 
loopback_pointer(struct snd_pcm_substream * substream)863 static snd_pcm_uframes_t loopback_pointer(struct snd_pcm_substream *substream)
864 {
865 	struct snd_pcm_runtime *runtime = substream->runtime;
866 	struct loopback_pcm *dpcm = runtime->private_data;
867 	snd_pcm_uframes_t pos;
868 
869 	spin_lock(&dpcm->cable->lock);
870 	if (dpcm->cable->ops->pos_update)
871 		dpcm->cable->ops->pos_update(dpcm->cable);
872 	pos = dpcm->buf_pos;
873 	spin_unlock(&dpcm->cable->lock);
874 	return bytes_to_frames(runtime, pos);
875 }
876 
877 static const struct snd_pcm_hardware loopback_pcm_hardware =
878 {
879 	.info =		(SNDRV_PCM_INFO_INTERLEAVED | SNDRV_PCM_INFO_MMAP |
880 			 SNDRV_PCM_INFO_MMAP_VALID | SNDRV_PCM_INFO_PAUSE |
881 			 SNDRV_PCM_INFO_RESUME),
882 	.formats =	(SNDRV_PCM_FMTBIT_S16_LE | SNDRV_PCM_FMTBIT_S16_BE |
883 			 SNDRV_PCM_FMTBIT_S24_LE | SNDRV_PCM_FMTBIT_S24_BE |
884 			 SNDRV_PCM_FMTBIT_S24_3LE | SNDRV_PCM_FMTBIT_S24_3BE |
885 			 SNDRV_PCM_FMTBIT_S32_LE | SNDRV_PCM_FMTBIT_S32_BE |
886 			 SNDRV_PCM_FMTBIT_FLOAT_LE | SNDRV_PCM_FMTBIT_FLOAT_BE),
887 	.rates =	SNDRV_PCM_RATE_CONTINUOUS | SNDRV_PCM_RATE_8000_192000,
888 	.rate_min =		8000,
889 	.rate_max =		192000,
890 	.channels_min =		1,
891 	.channels_max =		32,
892 	.buffer_bytes_max =	2 * 1024 * 1024,
893 	.period_bytes_min =	64,
894 	/* note check overflow in frac_pos() using pcm_rate_shift before
895 	   changing period_bytes_max value */
896 	.period_bytes_max =	1024 * 1024,
897 	.periods_min =		1,
898 	.periods_max =		1024,
899 	.fifo_size =		0,
900 };
901 
loopback_runtime_free(struct snd_pcm_runtime * runtime)902 static void loopback_runtime_free(struct snd_pcm_runtime *runtime)
903 {
904 	struct loopback_pcm *dpcm = runtime->private_data;
905 	kfree(dpcm);
906 }
907 
loopback_hw_free(struct snd_pcm_substream * substream)908 static int loopback_hw_free(struct snd_pcm_substream *substream)
909 {
910 	struct snd_pcm_runtime *runtime = substream->runtime;
911 	struct loopback_pcm *dpcm = runtime->private_data;
912 	struct loopback_cable *cable = dpcm->cable;
913 
914 	mutex_lock(&dpcm->loopback->cable_lock);
915 	cable->valid &= ~(1 << substream->stream);
916 	mutex_unlock(&dpcm->loopback->cable_lock);
917 	return 0;
918 }
919 
get_cable_index(struct snd_pcm_substream * substream)920 static unsigned int get_cable_index(struct snd_pcm_substream *substream)
921 {
922 	if (!substream->pcm->device)
923 		return substream->stream;
924 	else
925 		return !substream->stream;
926 }
927 
rule_format(struct snd_pcm_hw_params * params,struct snd_pcm_hw_rule * rule)928 static int rule_format(struct snd_pcm_hw_params *params,
929 		       struct snd_pcm_hw_rule *rule)
930 {
931 	struct loopback_pcm *dpcm = rule->private;
932 	struct loopback_cable *cable = dpcm->cable;
933 	struct snd_mask m;
934 
935 	snd_mask_none(&m);
936 	mutex_lock(&dpcm->loopback->cable_lock);
937 	m.bits[0] = (u_int32_t)cable->hw.formats;
938 	m.bits[1] = (u_int32_t)(cable->hw.formats >> 32);
939 	mutex_unlock(&dpcm->loopback->cable_lock);
940 	return snd_mask_refine(hw_param_mask(params, rule->var), &m);
941 }
942 
rule_rate(struct snd_pcm_hw_params * params,struct snd_pcm_hw_rule * rule)943 static int rule_rate(struct snd_pcm_hw_params *params,
944 		     struct snd_pcm_hw_rule *rule)
945 {
946 	struct loopback_pcm *dpcm = rule->private;
947 	struct loopback_cable *cable = dpcm->cable;
948 	struct snd_interval t;
949 
950 	mutex_lock(&dpcm->loopback->cable_lock);
951 	t.min = cable->hw.rate_min;
952 	t.max = cable->hw.rate_max;
953 	mutex_unlock(&dpcm->loopback->cable_lock);
954         t.openmin = t.openmax = 0;
955         t.integer = 0;
956 	return snd_interval_refine(hw_param_interval(params, rule->var), &t);
957 }
958 
rule_channels(struct snd_pcm_hw_params * params,struct snd_pcm_hw_rule * rule)959 static int rule_channels(struct snd_pcm_hw_params *params,
960 			 struct snd_pcm_hw_rule *rule)
961 {
962 	struct loopback_pcm *dpcm = rule->private;
963 	struct loopback_cable *cable = dpcm->cable;
964 	struct snd_interval t;
965 
966 	mutex_lock(&dpcm->loopback->cable_lock);
967 	t.min = cable->hw.channels_min;
968 	t.max = cable->hw.channels_max;
969 	mutex_unlock(&dpcm->loopback->cable_lock);
970         t.openmin = t.openmax = 0;
971         t.integer = 0;
972 	return snd_interval_refine(hw_param_interval(params, rule->var), &t);
973 }
974 
rule_period_bytes(struct snd_pcm_hw_params * params,struct snd_pcm_hw_rule * rule)975 static int rule_period_bytes(struct snd_pcm_hw_params *params,
976 			     struct snd_pcm_hw_rule *rule)
977 {
978 	struct loopback_pcm *dpcm = rule->private;
979 	struct loopback_cable *cable = dpcm->cable;
980 	struct snd_interval t;
981 
982 	mutex_lock(&dpcm->loopback->cable_lock);
983 	t.min = cable->hw.period_bytes_min;
984 	t.max = cable->hw.period_bytes_max;
985 	mutex_unlock(&dpcm->loopback->cable_lock);
986 	t.openmin = 0;
987 	t.openmax = 0;
988 	t.integer = 0;
989 	return snd_interval_refine(hw_param_interval(params, rule->var), &t);
990 }
991 
free_cable(struct snd_pcm_substream * substream)992 static void free_cable(struct snd_pcm_substream *substream)
993 {
994 	struct loopback *loopback = substream->private_data;
995 	int dev = get_cable_index(substream);
996 	struct loopback_cable *cable;
997 
998 	cable = loopback->cables[substream->number][dev];
999 	if (!cable)
1000 		return;
1001 	if (cable->streams[!substream->stream]) {
1002 		/* other stream is still alive */
1003 		spin_lock_irq(&cable->lock);
1004 		cable->streams[substream->stream] = NULL;
1005 		spin_unlock_irq(&cable->lock);
1006 	} else {
1007 		struct loopback_pcm *dpcm = substream->runtime->private_data;
1008 
1009 		if (cable->ops && cable->ops->close_cable && dpcm)
1010 			cable->ops->close_cable(dpcm);
1011 		/* free the cable */
1012 		loopback->cables[substream->number][dev] = NULL;
1013 		kfree(cable);
1014 	}
1015 }
1016 
loopback_jiffies_timer_open(struct loopback_pcm * dpcm)1017 static int loopback_jiffies_timer_open(struct loopback_pcm *dpcm)
1018 {
1019 	timer_setup(&dpcm->timer, loopback_jiffies_timer_function, 0);
1020 
1021 	return 0;
1022 }
1023 
1024 static const struct loopback_ops loopback_jiffies_timer_ops = {
1025 	.open = loopback_jiffies_timer_open,
1026 	.start = loopback_jiffies_timer_start,
1027 	.stop = loopback_jiffies_timer_stop,
1028 	.stop_sync = loopback_jiffies_timer_stop_sync,
1029 	.close_substream = loopback_jiffies_timer_stop_sync,
1030 	.pos_update = loopback_jiffies_timer_pos_update,
1031 	.dpcm_info = loopback_jiffies_timer_dpcm_info,
1032 };
1033 
loopback_parse_timer_id(const char * str,struct snd_timer_id * tid)1034 static int loopback_parse_timer_id(const char *str,
1035 				   struct snd_timer_id *tid)
1036 {
1037 	/* [<pref>:](<card name>|<card idx>)[{.,}<dev idx>[{.,}<subdev idx>]] */
1038 	const char * const sep_dev = ".,";
1039 	const char * const sep_pref = ":";
1040 	const char *name = str;
1041 	char *sep, save = '\0';
1042 	int card_idx = 0, dev = 0, subdev = 0;
1043 	int err;
1044 
1045 	sep = strpbrk(str, sep_pref);
1046 	if (sep)
1047 		name = sep + 1;
1048 	sep = strpbrk(name, sep_dev);
1049 	if (sep) {
1050 		save = *sep;
1051 		*sep = '\0';
1052 	}
1053 	err = kstrtoint(name, 0, &card_idx);
1054 	if (err == -EINVAL) {
1055 		/* Must be the name, not number */
1056 		for (card_idx = 0; card_idx < snd_ecards_limit; card_idx++) {
1057 			struct snd_card *card = snd_card_ref(card_idx);
1058 
1059 			if (card) {
1060 				if (!strcmp(card->id, name))
1061 					err = 0;
1062 				snd_card_unref(card);
1063 			}
1064 			if (!err)
1065 				break;
1066 		}
1067 	}
1068 	if (sep) {
1069 		*sep = save;
1070 		if (!err) {
1071 			char *sep2, save2 = '\0';
1072 
1073 			sep2 = strpbrk(sep + 1, sep_dev);
1074 			if (sep2) {
1075 				save2 = *sep2;
1076 				*sep2 = '\0';
1077 			}
1078 			err = kstrtoint(sep + 1, 0, &dev);
1079 			if (sep2) {
1080 				*sep2 = save2;
1081 				if (!err)
1082 					err = kstrtoint(sep2 + 1, 0, &subdev);
1083 			}
1084 		}
1085 	}
1086 	if (!err && tid) {
1087 		tid->card = card_idx;
1088 		tid->device = dev;
1089 		tid->subdevice = subdev;
1090 	}
1091 	return err;
1092 }
1093 
1094 /* call in loopback->cable_lock */
loopback_snd_timer_open(struct loopback_pcm * dpcm)1095 static int loopback_snd_timer_open(struct loopback_pcm *dpcm)
1096 {
1097 	int err = 0;
1098 	struct snd_timer_id tid = {
1099 		.dev_class = SNDRV_TIMER_CLASS_PCM,
1100 		.dev_sclass = SNDRV_TIMER_SCLASS_APPLICATION,
1101 	};
1102 	struct snd_timer_instance *timeri;
1103 	struct loopback_cable *cable = dpcm->cable;
1104 
1105 	/* check if timer was already opened. It is only opened once
1106 	 * per playback and capture subdevice (aka cable).
1107 	 */
1108 	if (cable->snd_timer.instance)
1109 		goto exit;
1110 
1111 	err = loopback_parse_timer_id(dpcm->loopback->timer_source, &tid);
1112 	if (err < 0) {
1113 		pcm_err(dpcm->substream->pcm,
1114 			"Parsing timer source \'%s\' failed with %d",
1115 			dpcm->loopback->timer_source, err);
1116 		goto exit;
1117 	}
1118 
1119 	cable->snd_timer.stream = dpcm->substream->stream;
1120 	cable->snd_timer.id = tid;
1121 
1122 	timeri = snd_timer_instance_new(dpcm->loopback->card->id);
1123 	if (!timeri) {
1124 		err = -ENOMEM;
1125 		goto exit;
1126 	}
1127 	/* The callback has to be called from another work. If
1128 	 * SNDRV_TIMER_IFLG_FAST is specified it will be called from the
1129 	 * snd_pcm_period_elapsed() call of the selected sound card.
1130 	 * snd_pcm_period_elapsed() helds snd_pcm_stream_lock_irqsave().
1131 	 * Due to our callback loopback_snd_timer_function() also calls
1132 	 * snd_pcm_period_elapsed() which calls snd_pcm_stream_lock_irqsave().
1133 	 * This would end up in a dead lock.
1134 	 */
1135 	timeri->flags |= SNDRV_TIMER_IFLG_AUTO;
1136 	timeri->callback = loopback_snd_timer_function;
1137 	timeri->callback_data = (void *)cable;
1138 	timeri->ccallback = loopback_snd_timer_event;
1139 
1140 	/* initialise a work used for draining */
1141 	INIT_WORK(&cable->snd_timer.event_work, loopback_snd_timer_work);
1142 
1143 	/* The mutex loopback->cable_lock is kept locked.
1144 	 * Therefore snd_timer_open() cannot be called a second time
1145 	 * by the other device of the same cable.
1146 	 * Therefore the following issue cannot happen:
1147 	 * [proc1] Call loopback_timer_open() ->
1148 	 *	   Unlock cable->lock for snd_timer_close/open() call
1149 	 * [proc2] Call loopback_timer_open() -> snd_timer_open(),
1150 	 *	   snd_timer_start()
1151 	 * [proc1] Call snd_timer_open() and overwrite running timer
1152 	 *	   instance
1153 	 */
1154 	err = snd_timer_open(timeri, &cable->snd_timer.id, current->pid);
1155 	if (err < 0) {
1156 		pcm_err(dpcm->substream->pcm,
1157 			"snd_timer_open (%d,%d,%d) failed with %d",
1158 			cable->snd_timer.id.card,
1159 			cable->snd_timer.id.device,
1160 			cable->snd_timer.id.subdevice,
1161 			err);
1162 		snd_timer_instance_free(timeri);
1163 		goto exit;
1164 	}
1165 
1166 	cable->snd_timer.instance = timeri;
1167 
1168 exit:
1169 	return err;
1170 }
1171 
1172 /* stop_sync() is not required for sound timer because it does not need to be
1173  * restarted in loopback_prepare() on Xrun recovery
1174  */
1175 static const struct loopback_ops loopback_snd_timer_ops = {
1176 	.open = loopback_snd_timer_open,
1177 	.start = loopback_snd_timer_start,
1178 	.stop = loopback_snd_timer_stop,
1179 	.close_cable = loopback_snd_timer_close_cable,
1180 	.dpcm_info = loopback_snd_timer_dpcm_info,
1181 };
1182 
loopback_open(struct snd_pcm_substream * substream)1183 static int loopback_open(struct snd_pcm_substream *substream)
1184 {
1185 	struct snd_pcm_runtime *runtime = substream->runtime;
1186 	struct loopback *loopback = substream->private_data;
1187 	struct loopback_pcm *dpcm;
1188 	struct loopback_cable *cable = NULL;
1189 	int err = 0;
1190 	int dev = get_cable_index(substream);
1191 
1192 	mutex_lock(&loopback->cable_lock);
1193 	dpcm = kzalloc(sizeof(*dpcm), GFP_KERNEL);
1194 	if (!dpcm) {
1195 		err = -ENOMEM;
1196 		goto unlock;
1197 	}
1198 	dpcm->loopback = loopback;
1199 	dpcm->substream = substream;
1200 
1201 	cable = loopback->cables[substream->number][dev];
1202 	if (!cable) {
1203 		cable = kzalloc(sizeof(*cable), GFP_KERNEL);
1204 		if (!cable) {
1205 			err = -ENOMEM;
1206 			goto unlock;
1207 		}
1208 		spin_lock_init(&cable->lock);
1209 		cable->hw = loopback_pcm_hardware;
1210 		if (loopback->timer_source)
1211 			cable->ops = &loopback_snd_timer_ops;
1212 		else
1213 			cable->ops = &loopback_jiffies_timer_ops;
1214 		loopback->cables[substream->number][dev] = cable;
1215 	}
1216 	dpcm->cable = cable;
1217 	runtime->private_data = dpcm;
1218 
1219 	if (cable->ops->open) {
1220 		err = cable->ops->open(dpcm);
1221 		if (err < 0)
1222 			goto unlock;
1223 	}
1224 
1225 	snd_pcm_hw_constraint_integer(runtime, SNDRV_PCM_HW_PARAM_PERIODS);
1226 
1227 	/* use dynamic rules based on actual runtime->hw values */
1228 	/* note that the default rules created in the PCM midlevel code */
1229 	/* are cached -> they do not reflect the actual state */
1230 	err = snd_pcm_hw_rule_add(runtime, 0,
1231 				  SNDRV_PCM_HW_PARAM_FORMAT,
1232 				  rule_format, dpcm,
1233 				  SNDRV_PCM_HW_PARAM_FORMAT, -1);
1234 	if (err < 0)
1235 		goto unlock;
1236 	err = snd_pcm_hw_rule_add(runtime, 0,
1237 				  SNDRV_PCM_HW_PARAM_RATE,
1238 				  rule_rate, dpcm,
1239 				  SNDRV_PCM_HW_PARAM_RATE, -1);
1240 	if (err < 0)
1241 		goto unlock;
1242 	err = snd_pcm_hw_rule_add(runtime, 0,
1243 				  SNDRV_PCM_HW_PARAM_CHANNELS,
1244 				  rule_channels, dpcm,
1245 				  SNDRV_PCM_HW_PARAM_CHANNELS, -1);
1246 	if (err < 0)
1247 		goto unlock;
1248 
1249 	/* In case of sound timer the period time of both devices of the same
1250 	 * loop has to be the same.
1251 	 * This rule only takes effect if a sound timer was chosen
1252 	 */
1253 	if (cable->snd_timer.instance) {
1254 		err = snd_pcm_hw_rule_add(runtime, 0,
1255 					  SNDRV_PCM_HW_PARAM_PERIOD_BYTES,
1256 					  rule_period_bytes, dpcm,
1257 					  SNDRV_PCM_HW_PARAM_PERIOD_BYTES, -1);
1258 		if (err < 0)
1259 			goto unlock;
1260 	}
1261 
1262 	/* loopback_runtime_free() has not to be called if kfree(dpcm) was
1263 	 * already called here. Otherwise it will end up with a double free.
1264 	 */
1265 	runtime->private_free = loopback_runtime_free;
1266 	if (get_notify(dpcm))
1267 		runtime->hw = loopback_pcm_hardware;
1268 	else
1269 		runtime->hw = cable->hw;
1270 
1271 	spin_lock_irq(&cable->lock);
1272 	cable->streams[substream->stream] = dpcm;
1273 	spin_unlock_irq(&cable->lock);
1274 
1275  unlock:
1276 	if (err < 0) {
1277 		free_cable(substream);
1278 		kfree(dpcm);
1279 	}
1280 	mutex_unlock(&loopback->cable_lock);
1281 	return err;
1282 }
1283 
loopback_close(struct snd_pcm_substream * substream)1284 static int loopback_close(struct snd_pcm_substream *substream)
1285 {
1286 	struct loopback *loopback = substream->private_data;
1287 	struct loopback_pcm *dpcm = substream->runtime->private_data;
1288 	int err = 0;
1289 
1290 	if (dpcm->cable->ops->close_substream)
1291 		err = dpcm->cable->ops->close_substream(dpcm);
1292 	mutex_lock(&loopback->cable_lock);
1293 	free_cable(substream);
1294 	mutex_unlock(&loopback->cable_lock);
1295 	return err;
1296 }
1297 
1298 static const struct snd_pcm_ops loopback_pcm_ops = {
1299 	.open =		loopback_open,
1300 	.close =	loopback_close,
1301 	.hw_free =	loopback_hw_free,
1302 	.prepare =	loopback_prepare,
1303 	.trigger =	loopback_trigger,
1304 	.pointer =	loopback_pointer,
1305 };
1306 
loopback_pcm_new(struct loopback * loopback,int device,int substreams)1307 static int loopback_pcm_new(struct loopback *loopback,
1308 			    int device, int substreams)
1309 {
1310 	struct snd_pcm *pcm;
1311 	int err;
1312 
1313 	err = snd_pcm_new(loopback->card, "Loopback PCM", device,
1314 			  substreams, substreams, &pcm);
1315 	if (err < 0)
1316 		return err;
1317 	snd_pcm_set_ops(pcm, SNDRV_PCM_STREAM_PLAYBACK, &loopback_pcm_ops);
1318 	snd_pcm_set_ops(pcm, SNDRV_PCM_STREAM_CAPTURE, &loopback_pcm_ops);
1319 	snd_pcm_set_managed_buffer_all(pcm, SNDRV_DMA_TYPE_VMALLOC, NULL, 0, 0);
1320 
1321 	pcm->private_data = loopback;
1322 	pcm->info_flags = 0;
1323 	strcpy(pcm->name, "Loopback PCM");
1324 
1325 	loopback->pcm[device] = pcm;
1326 	return 0;
1327 }
1328 
loopback_rate_shift_info(struct snd_kcontrol * kcontrol,struct snd_ctl_elem_info * uinfo)1329 static int loopback_rate_shift_info(struct snd_kcontrol *kcontrol,
1330 				    struct snd_ctl_elem_info *uinfo)
1331 {
1332 	uinfo->type = SNDRV_CTL_ELEM_TYPE_INTEGER;
1333 	uinfo->count = 1;
1334 	uinfo->value.integer.min = 80000;
1335 	uinfo->value.integer.max = 120000;
1336 	uinfo->value.integer.step = 1;
1337 	return 0;
1338 }
1339 
loopback_rate_shift_get(struct snd_kcontrol * kcontrol,struct snd_ctl_elem_value * ucontrol)1340 static int loopback_rate_shift_get(struct snd_kcontrol *kcontrol,
1341 				   struct snd_ctl_elem_value *ucontrol)
1342 {
1343 	struct loopback *loopback = snd_kcontrol_chip(kcontrol);
1344 
1345 	mutex_lock(&loopback->cable_lock);
1346 	ucontrol->value.integer.value[0] =
1347 		loopback->setup[kcontrol->id.subdevice]
1348 			       [kcontrol->id.device].rate_shift;
1349 	mutex_unlock(&loopback->cable_lock);
1350 	return 0;
1351 }
1352 
loopback_rate_shift_put(struct snd_kcontrol * kcontrol,struct snd_ctl_elem_value * ucontrol)1353 static int loopback_rate_shift_put(struct snd_kcontrol *kcontrol,
1354 				   struct snd_ctl_elem_value *ucontrol)
1355 {
1356 	struct loopback *loopback = snd_kcontrol_chip(kcontrol);
1357 	unsigned int val;
1358 	int change = 0;
1359 
1360 	val = ucontrol->value.integer.value[0];
1361 	if (val < 80000)
1362 		val = 80000;
1363 	if (val > 120000)
1364 		val = 120000;
1365 	mutex_lock(&loopback->cable_lock);
1366 	if (val != loopback->setup[kcontrol->id.subdevice]
1367 				  [kcontrol->id.device].rate_shift) {
1368 		loopback->setup[kcontrol->id.subdevice]
1369 			       [kcontrol->id.device].rate_shift = val;
1370 		change = 1;
1371 	}
1372 	mutex_unlock(&loopback->cable_lock);
1373 	return change;
1374 }
1375 
loopback_notify_get(struct snd_kcontrol * kcontrol,struct snd_ctl_elem_value * ucontrol)1376 static int loopback_notify_get(struct snd_kcontrol *kcontrol,
1377 			       struct snd_ctl_elem_value *ucontrol)
1378 {
1379 	struct loopback *loopback = snd_kcontrol_chip(kcontrol);
1380 
1381 	mutex_lock(&loopback->cable_lock);
1382 	ucontrol->value.integer.value[0] =
1383 		loopback->setup[kcontrol->id.subdevice]
1384 			       [kcontrol->id.device].notify;
1385 	mutex_unlock(&loopback->cable_lock);
1386 	return 0;
1387 }
1388 
loopback_notify_put(struct snd_kcontrol * kcontrol,struct snd_ctl_elem_value * ucontrol)1389 static int loopback_notify_put(struct snd_kcontrol *kcontrol,
1390 			       struct snd_ctl_elem_value *ucontrol)
1391 {
1392 	struct loopback *loopback = snd_kcontrol_chip(kcontrol);
1393 	unsigned int val;
1394 	int change = 0;
1395 
1396 	val = ucontrol->value.integer.value[0] ? 1 : 0;
1397 	mutex_lock(&loopback->cable_lock);
1398 	if (val != loopback->setup[kcontrol->id.subdevice]
1399 				[kcontrol->id.device].notify) {
1400 		loopback->setup[kcontrol->id.subdevice]
1401 			[kcontrol->id.device].notify = val;
1402 		change = 1;
1403 	}
1404 	mutex_unlock(&loopback->cable_lock);
1405 	return change;
1406 }
1407 
loopback_active_get(struct snd_kcontrol * kcontrol,struct snd_ctl_elem_value * ucontrol)1408 static int loopback_active_get(struct snd_kcontrol *kcontrol,
1409 			       struct snd_ctl_elem_value *ucontrol)
1410 {
1411 	struct loopback *loopback = snd_kcontrol_chip(kcontrol);
1412 	struct loopback_cable *cable;
1413 
1414 	unsigned int val = 0;
1415 
1416 	mutex_lock(&loopback->cable_lock);
1417 	cable = loopback->cables[kcontrol->id.subdevice][kcontrol->id.device ^ 1];
1418 	if (cable != NULL) {
1419 		unsigned int running = cable->running ^ cable->pause;
1420 
1421 		val = (running & (1 << SNDRV_PCM_STREAM_PLAYBACK)) ? 1 : 0;
1422 	}
1423 	mutex_unlock(&loopback->cable_lock);
1424 	ucontrol->value.integer.value[0] = val;
1425 	return 0;
1426 }
1427 
loopback_format_info(struct snd_kcontrol * kcontrol,struct snd_ctl_elem_info * uinfo)1428 static int loopback_format_info(struct snd_kcontrol *kcontrol,
1429 				struct snd_ctl_elem_info *uinfo)
1430 {
1431 	uinfo->type = SNDRV_CTL_ELEM_TYPE_INTEGER;
1432 	uinfo->count = 1;
1433 	uinfo->value.integer.min = 0;
1434 	uinfo->value.integer.max = (__force int)SNDRV_PCM_FORMAT_LAST;
1435 	uinfo->value.integer.step = 1;
1436 	return 0;
1437 }
1438 
loopback_format_get(struct snd_kcontrol * kcontrol,struct snd_ctl_elem_value * ucontrol)1439 static int loopback_format_get(struct snd_kcontrol *kcontrol,
1440 			       struct snd_ctl_elem_value *ucontrol)
1441 {
1442 	struct loopback *loopback = snd_kcontrol_chip(kcontrol);
1443 
1444 	ucontrol->value.integer.value[0] =
1445 		(__force int)loopback->setup[kcontrol->id.subdevice]
1446 			       [kcontrol->id.device].format;
1447 	return 0;
1448 }
1449 
loopback_rate_info(struct snd_kcontrol * kcontrol,struct snd_ctl_elem_info * uinfo)1450 static int loopback_rate_info(struct snd_kcontrol *kcontrol,
1451 			      struct snd_ctl_elem_info *uinfo)
1452 {
1453 	uinfo->type = SNDRV_CTL_ELEM_TYPE_INTEGER;
1454 	uinfo->count = 1;
1455 	uinfo->value.integer.min = 0;
1456 	uinfo->value.integer.max = 192000;
1457 	uinfo->value.integer.step = 1;
1458 	return 0;
1459 }
1460 
loopback_rate_get(struct snd_kcontrol * kcontrol,struct snd_ctl_elem_value * ucontrol)1461 static int loopback_rate_get(struct snd_kcontrol *kcontrol,
1462 			     struct snd_ctl_elem_value *ucontrol)
1463 {
1464 	struct loopback *loopback = snd_kcontrol_chip(kcontrol);
1465 
1466 	mutex_lock(&loopback->cable_lock);
1467 	ucontrol->value.integer.value[0] =
1468 		loopback->setup[kcontrol->id.subdevice]
1469 			       [kcontrol->id.device].rate;
1470 	mutex_unlock(&loopback->cable_lock);
1471 	return 0;
1472 }
1473 
loopback_channels_info(struct snd_kcontrol * kcontrol,struct snd_ctl_elem_info * uinfo)1474 static int loopback_channels_info(struct snd_kcontrol *kcontrol,
1475 				  struct snd_ctl_elem_info *uinfo)
1476 {
1477 	uinfo->type = SNDRV_CTL_ELEM_TYPE_INTEGER;
1478 	uinfo->count = 1;
1479 	uinfo->value.integer.min = 1;
1480 	uinfo->value.integer.max = 1024;
1481 	uinfo->value.integer.step = 1;
1482 	return 0;
1483 }
1484 
loopback_channels_get(struct snd_kcontrol * kcontrol,struct snd_ctl_elem_value * ucontrol)1485 static int loopback_channels_get(struct snd_kcontrol *kcontrol,
1486 				 struct snd_ctl_elem_value *ucontrol)
1487 {
1488 	struct loopback *loopback = snd_kcontrol_chip(kcontrol);
1489 
1490 	mutex_lock(&loopback->cable_lock);
1491 	ucontrol->value.integer.value[0] =
1492 		loopback->setup[kcontrol->id.subdevice]
1493 			       [kcontrol->id.device].channels;
1494 	mutex_unlock(&loopback->cable_lock);
1495 	return 0;
1496 }
1497 
1498 static const struct snd_kcontrol_new loopback_controls[]  = {
1499 {
1500 	.iface =        SNDRV_CTL_ELEM_IFACE_PCM,
1501 	.name =         "PCM Rate Shift 100000",
1502 	.info =         loopback_rate_shift_info,
1503 	.get =          loopback_rate_shift_get,
1504 	.put =          loopback_rate_shift_put,
1505 },
1506 {
1507 	.iface =        SNDRV_CTL_ELEM_IFACE_PCM,
1508 	.name =         "PCM Notify",
1509 	.info =         snd_ctl_boolean_mono_info,
1510 	.get =          loopback_notify_get,
1511 	.put =          loopback_notify_put,
1512 },
1513 #define ACTIVE_IDX 2
1514 {
1515 	.access =	SNDRV_CTL_ELEM_ACCESS_READ,
1516 	.iface =        SNDRV_CTL_ELEM_IFACE_PCM,
1517 	.name =         "PCM Slave Active",
1518 	.info =         snd_ctl_boolean_mono_info,
1519 	.get =          loopback_active_get,
1520 },
1521 #define FORMAT_IDX 3
1522 {
1523 	.access =	SNDRV_CTL_ELEM_ACCESS_READ,
1524 	.iface =        SNDRV_CTL_ELEM_IFACE_PCM,
1525 	.name =         "PCM Slave Format",
1526 	.info =         loopback_format_info,
1527 	.get =          loopback_format_get
1528 },
1529 #define RATE_IDX 4
1530 {
1531 	.access =	SNDRV_CTL_ELEM_ACCESS_READ,
1532 	.iface =        SNDRV_CTL_ELEM_IFACE_PCM,
1533 	.name =         "PCM Slave Rate",
1534 	.info =         loopback_rate_info,
1535 	.get =          loopback_rate_get
1536 },
1537 #define CHANNELS_IDX 5
1538 {
1539 	.access =	SNDRV_CTL_ELEM_ACCESS_READ,
1540 	.iface =        SNDRV_CTL_ELEM_IFACE_PCM,
1541 	.name =         "PCM Slave Channels",
1542 	.info =         loopback_channels_info,
1543 	.get =          loopback_channels_get
1544 }
1545 };
1546 
loopback_mixer_new(struct loopback * loopback,int notify)1547 static int loopback_mixer_new(struct loopback *loopback, int notify)
1548 {
1549 	struct snd_card *card = loopback->card;
1550 	struct snd_pcm *pcm;
1551 	struct snd_kcontrol *kctl;
1552 	struct loopback_setup *setup;
1553 	int err, dev, substr, substr_count, idx;
1554 
1555 	strcpy(card->mixername, "Loopback Mixer");
1556 	for (dev = 0; dev < 2; dev++) {
1557 		pcm = loopback->pcm[dev];
1558 		substr_count =
1559 		    pcm->streams[SNDRV_PCM_STREAM_CAPTURE].substream_count;
1560 		for (substr = 0; substr < substr_count; substr++) {
1561 			setup = &loopback->setup[substr][dev];
1562 			setup->notify = notify;
1563 			setup->rate_shift = NO_PITCH;
1564 			setup->format = SNDRV_PCM_FORMAT_S16_LE;
1565 			setup->rate = 48000;
1566 			setup->channels = 2;
1567 			for (idx = 0; idx < ARRAY_SIZE(loopback_controls);
1568 									idx++) {
1569 				kctl = snd_ctl_new1(&loopback_controls[idx],
1570 						    loopback);
1571 				if (!kctl)
1572 					return -ENOMEM;
1573 				kctl->id.device = dev;
1574 				kctl->id.subdevice = substr;
1575 
1576 				/* Add the control before copying the id so that
1577 				 * the numid field of the id is set in the copy.
1578 				 */
1579 				err = snd_ctl_add(card, kctl);
1580 				if (err < 0)
1581 					return err;
1582 
1583 				switch (idx) {
1584 				case ACTIVE_IDX:
1585 					setup->active_id = kctl->id;
1586 					break;
1587 				case FORMAT_IDX:
1588 					setup->format_id = kctl->id;
1589 					break;
1590 				case RATE_IDX:
1591 					setup->rate_id = kctl->id;
1592 					break;
1593 				case CHANNELS_IDX:
1594 					setup->channels_id = kctl->id;
1595 					break;
1596 				default:
1597 					break;
1598 				}
1599 			}
1600 		}
1601 	}
1602 	return 0;
1603 }
1604 
print_dpcm_info(struct snd_info_buffer * buffer,struct loopback_pcm * dpcm,const char * id)1605 static void print_dpcm_info(struct snd_info_buffer *buffer,
1606 			    struct loopback_pcm *dpcm,
1607 			    const char *id)
1608 {
1609 	snd_iprintf(buffer, "  %s\n", id);
1610 	if (dpcm == NULL) {
1611 		snd_iprintf(buffer, "    inactive\n");
1612 		return;
1613 	}
1614 	snd_iprintf(buffer, "    buffer_size:\t%u\n", dpcm->pcm_buffer_size);
1615 	snd_iprintf(buffer, "    buffer_pos:\t\t%u\n", dpcm->buf_pos);
1616 	snd_iprintf(buffer, "    silent_size:\t%u\n", dpcm->silent_size);
1617 	snd_iprintf(buffer, "    period_size:\t%u\n", dpcm->pcm_period_size);
1618 	snd_iprintf(buffer, "    bytes_per_sec:\t%u\n", dpcm->pcm_bps);
1619 	snd_iprintf(buffer, "    sample_align:\t%u\n", dpcm->pcm_salign);
1620 	snd_iprintf(buffer, "    rate_shift:\t\t%u\n", dpcm->pcm_rate_shift);
1621 	if (dpcm->cable->ops->dpcm_info)
1622 		dpcm->cable->ops->dpcm_info(dpcm, buffer);
1623 }
1624 
print_substream_info(struct snd_info_buffer * buffer,struct loopback * loopback,int sub,int num)1625 static void print_substream_info(struct snd_info_buffer *buffer,
1626 				 struct loopback *loopback,
1627 				 int sub,
1628 				 int num)
1629 {
1630 	struct loopback_cable *cable = loopback->cables[sub][num];
1631 
1632 	snd_iprintf(buffer, "Cable %i substream %i:\n", num, sub);
1633 	if (cable == NULL) {
1634 		snd_iprintf(buffer, "  inactive\n");
1635 		return;
1636 	}
1637 	snd_iprintf(buffer, "  valid: %u\n", cable->valid);
1638 	snd_iprintf(buffer, "  running: %u\n", cable->running);
1639 	snd_iprintf(buffer, "  pause: %u\n", cable->pause);
1640 	print_dpcm_info(buffer, cable->streams[0], "Playback");
1641 	print_dpcm_info(buffer, cable->streams[1], "Capture");
1642 }
1643 
print_cable_info(struct snd_info_entry * entry,struct snd_info_buffer * buffer)1644 static void print_cable_info(struct snd_info_entry *entry,
1645 			     struct snd_info_buffer *buffer)
1646 {
1647 	struct loopback *loopback = entry->private_data;
1648 	int sub, num;
1649 
1650 	mutex_lock(&loopback->cable_lock);
1651 	num = entry->name[strlen(entry->name)-1];
1652 	num = num == '0' ? 0 : 1;
1653 	for (sub = 0; sub < MAX_PCM_SUBSTREAMS; sub++)
1654 		print_substream_info(buffer, loopback, sub, num);
1655 	mutex_unlock(&loopback->cable_lock);
1656 }
1657 
loopback_cable_proc_new(struct loopback * loopback,int cidx)1658 static int loopback_cable_proc_new(struct loopback *loopback, int cidx)
1659 {
1660 	char name[32];
1661 
1662 	snprintf(name, sizeof(name), "cable#%d", cidx);
1663 	return snd_card_ro_proc_new(loopback->card, name, loopback,
1664 				    print_cable_info);
1665 }
1666 
loopback_set_timer_source(struct loopback * loopback,const char * value)1667 static void loopback_set_timer_source(struct loopback *loopback,
1668 				      const char *value)
1669 {
1670 	if (loopback->timer_source) {
1671 		devm_kfree(loopback->card->dev, loopback->timer_source);
1672 		loopback->timer_source = NULL;
1673 	}
1674 	if (value && *value)
1675 		loopback->timer_source = devm_kstrdup(loopback->card->dev,
1676 						      value, GFP_KERNEL);
1677 }
1678 
print_timer_source_info(struct snd_info_entry * entry,struct snd_info_buffer * buffer)1679 static void print_timer_source_info(struct snd_info_entry *entry,
1680 				    struct snd_info_buffer *buffer)
1681 {
1682 	struct loopback *loopback = entry->private_data;
1683 
1684 	mutex_lock(&loopback->cable_lock);
1685 	snd_iprintf(buffer, "%s\n",
1686 		    loopback->timer_source ? loopback->timer_source : "");
1687 	mutex_unlock(&loopback->cable_lock);
1688 }
1689 
change_timer_source_info(struct snd_info_entry * entry,struct snd_info_buffer * buffer)1690 static void change_timer_source_info(struct snd_info_entry *entry,
1691 				     struct snd_info_buffer *buffer)
1692 {
1693 	struct loopback *loopback = entry->private_data;
1694 	char line[64];
1695 
1696 	mutex_lock(&loopback->cable_lock);
1697 	if (!snd_info_get_line(buffer, line, sizeof(line)))
1698 		loopback_set_timer_source(loopback, strim(line));
1699 	mutex_unlock(&loopback->cable_lock);
1700 }
1701 
loopback_timer_source_proc_new(struct loopback * loopback)1702 static int loopback_timer_source_proc_new(struct loopback *loopback)
1703 {
1704 	return snd_card_rw_proc_new(loopback->card, "timer_source", loopback,
1705 				    print_timer_source_info,
1706 				    change_timer_source_info);
1707 }
1708 
loopback_probe(struct platform_device * devptr)1709 static int loopback_probe(struct platform_device *devptr)
1710 {
1711 	struct snd_card *card;
1712 	struct loopback *loopback;
1713 	int dev = devptr->id;
1714 	int err;
1715 
1716 	err = snd_devm_card_new(&devptr->dev, index[dev], id[dev], THIS_MODULE,
1717 				sizeof(struct loopback), &card);
1718 	if (err < 0)
1719 		return err;
1720 	loopback = card->private_data;
1721 
1722 	if (pcm_substreams[dev] < 1)
1723 		pcm_substreams[dev] = 1;
1724 	if (pcm_substreams[dev] > MAX_PCM_SUBSTREAMS)
1725 		pcm_substreams[dev] = MAX_PCM_SUBSTREAMS;
1726 
1727 	loopback->card = card;
1728 	loopback_set_timer_source(loopback, timer_source[dev]);
1729 
1730 	mutex_init(&loopback->cable_lock);
1731 
1732 	err = loopback_pcm_new(loopback, 0, pcm_substreams[dev]);
1733 	if (err < 0)
1734 		return err;
1735 	err = loopback_pcm_new(loopback, 1, pcm_substreams[dev]);
1736 	if (err < 0)
1737 		return err;
1738 	err = loopback_mixer_new(loopback, pcm_notify[dev] ? 1 : 0);
1739 	if (err < 0)
1740 		return err;
1741 	loopback_cable_proc_new(loopback, 0);
1742 	loopback_cable_proc_new(loopback, 1);
1743 	loopback_timer_source_proc_new(loopback);
1744 	strcpy(card->driver, "Loopback");
1745 	strcpy(card->shortname, "Loopback");
1746 	sprintf(card->longname, "Loopback %i", dev + 1);
1747 	err = snd_card_register(card);
1748 	if (err < 0)
1749 		return err;
1750 	platform_set_drvdata(devptr, card);
1751 	return 0;
1752 }
1753 
1754 #ifdef CONFIG_PM_SLEEP
loopback_suspend(struct device * pdev)1755 static int loopback_suspend(struct device *pdev)
1756 {
1757 	struct snd_card *card = dev_get_drvdata(pdev);
1758 
1759 	snd_power_change_state(card, SNDRV_CTL_POWER_D3hot);
1760 	return 0;
1761 }
1762 
loopback_resume(struct device * pdev)1763 static int loopback_resume(struct device *pdev)
1764 {
1765 	struct snd_card *card = dev_get_drvdata(pdev);
1766 
1767 	snd_power_change_state(card, SNDRV_CTL_POWER_D0);
1768 	return 0;
1769 }
1770 
1771 static SIMPLE_DEV_PM_OPS(loopback_pm, loopback_suspend, loopback_resume);
1772 #define LOOPBACK_PM_OPS	&loopback_pm
1773 #else
1774 #define LOOPBACK_PM_OPS	NULL
1775 #endif
1776 
1777 #define SND_LOOPBACK_DRIVER	"snd_aloop"
1778 
1779 static struct platform_driver loopback_driver = {
1780 	.probe		= loopback_probe,
1781 	.driver		= {
1782 		.name	= SND_LOOPBACK_DRIVER,
1783 		.pm	= LOOPBACK_PM_OPS,
1784 	},
1785 };
1786 
loopback_unregister_all(void)1787 static void loopback_unregister_all(void)
1788 {
1789 	int i;
1790 
1791 	for (i = 0; i < ARRAY_SIZE(devices); ++i)
1792 		platform_device_unregister(devices[i]);
1793 	platform_driver_unregister(&loopback_driver);
1794 }
1795 
alsa_card_loopback_init(void)1796 static int __init alsa_card_loopback_init(void)
1797 {
1798 	int i, err, cards;
1799 
1800 	err = platform_driver_register(&loopback_driver);
1801 	if (err < 0)
1802 		return err;
1803 
1804 
1805 	cards = 0;
1806 	for (i = 0; i < SNDRV_CARDS; i++) {
1807 		struct platform_device *device;
1808 		if (!enable[i])
1809 			continue;
1810 		device = platform_device_register_simple(SND_LOOPBACK_DRIVER,
1811 							 i, NULL, 0);
1812 		if (IS_ERR(device))
1813 			continue;
1814 		if (!platform_get_drvdata(device)) {
1815 			platform_device_unregister(device);
1816 			continue;
1817 		}
1818 		devices[i] = device;
1819 		cards++;
1820 	}
1821 	if (!cards) {
1822 #ifdef MODULE
1823 		printk(KERN_ERR "aloop: No loopback enabled\n");
1824 #endif
1825 		loopback_unregister_all();
1826 		return -ENODEV;
1827 	}
1828 	return 0;
1829 }
1830 
alsa_card_loopback_exit(void)1831 static void __exit alsa_card_loopback_exit(void)
1832 {
1833 	loopback_unregister_all();
1834 }
1835 
1836 module_init(alsa_card_loopback_init)
1837 module_exit(alsa_card_loopback_exit)
1838