1 // SPDX-License-Identifier: GPL-2.0-or-later
6 * Copyright (c) by Jaroslav Kysela <perex@perex.cz>
8 * More accurate positioning and full-duplex support:
9 * Copyright (c) Ahmet İnan <ainan at mathematik.uni-freiburg.de>
11 * Major (almost complete) rewrite:
12 * Copyright (c) by Takashi Iwai <tiwai@suse.de>
14 * A next major update in 2010 (separate timers for playback and capture):
15 * Copyright (c) Jaroslav Kysela <perex@perex.cz>
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>
33 MODULE_AUTHOR("Jaroslav Kysela <perex@perex.cz>");
34 MODULE_DESCRIPTION("A loopback soundcard");
35 MODULE_LICENSE("GPL");
37 #define MAX_PCM_SUBSTREAMS 8
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];
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].");
59 #define NO_PITCH 100000
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)
65 struct loopback_cable;
70 * call in loopback->cable_lock
72 int (*open)(struct loopback_pcm *dpcm);
76 int (*start)(struct loopback_pcm *dpcm);
80 int (*stop)(struct loopback_pcm *dpcm);
82 int (*stop_sync)(struct loopback_pcm *dpcm);
84 int (*close_substream)(struct loopback_pcm *dpcm);
86 * call in loopback->cable_lock
88 int (*close_cable)(struct loopback_pcm *dpcm);
92 unsigned int (*pos_update)(struct loopback_cable *cable);
94 void (*dpcm_info)(struct loopback_pcm *dpcm,
95 struct snd_info_buffer *buffer);
98 struct loopback_cable {
100 struct loopback_pcm *streams[2];
101 struct snd_pcm_hardware hw;
104 unsigned int running;
107 const struct loopback_ops *ops;
108 /* If sound timer is used */
111 struct snd_timer_id id;
112 struct work_struct event_work;
113 struct snd_timer_instance *instance;
117 struct loopback_setup {
118 unsigned int notify: 1;
119 unsigned int rate_shift;
120 snd_pcm_format_t format;
122 snd_pcm_access_t access;
123 unsigned int channels;
124 struct snd_ctl_elem_id active_id;
125 struct snd_ctl_elem_id format_id;
126 struct snd_ctl_elem_id rate_id;
127 struct snd_ctl_elem_id channels_id;
128 struct snd_ctl_elem_id access_id;
132 struct snd_card *card;
133 struct mutex cable_lock;
134 struct loopback_cable *cables[MAX_PCM_SUBSTREAMS][2];
135 struct snd_pcm *pcm[2];
136 struct loopback_setup setup[MAX_PCM_SUBSTREAMS][2];
137 const char *timer_source;
140 struct loopback_pcm {
141 struct loopback *loopback;
142 struct snd_pcm_substream *substream;
143 struct loopback_cable *cable;
144 unsigned int pcm_buffer_size;
145 unsigned int buf_pos; /* position in buffer */
146 unsigned int silent_size;
148 unsigned int pcm_period_size;
149 unsigned int pcm_bps; /* bytes per second */
150 unsigned int pcm_salign; /* bytes per sample * channels */
151 unsigned int pcm_rate_shift; /* rate shift value */
153 unsigned int period_update_pending :1;
155 unsigned int irq_pos; /* fractional IRQ position in jiffies
158 unsigned int period_size_frac; /* period size in jiffies ticks */
159 unsigned int last_drift;
160 unsigned long last_jiffies;
161 /* If jiffies timer is used */
162 struct timer_list timer;
164 /* size of per channel buffer in case of non-interleaved access */
165 unsigned int channel_buf_n;
168 static struct platform_device *devices[SNDRV_CARDS];
170 static inline unsigned int byte_pos(struct loopback_pcm *dpcm, unsigned int x)
172 if (dpcm->pcm_rate_shift == NO_PITCH) {
175 x = div_u64(NO_PITCH * (unsigned long long)x,
176 HZ * (unsigned long long)dpcm->pcm_rate_shift);
178 return x - (x % dpcm->pcm_salign);
181 static inline unsigned int frac_pos(struct loopback_pcm *dpcm, unsigned int x)
183 if (dpcm->pcm_rate_shift == NO_PITCH) { /* no pitch */
186 x = div_u64(dpcm->pcm_rate_shift * (unsigned long long)x * HZ,
192 static inline struct loopback_setup *get_setup(struct loopback_pcm *dpcm)
194 int device = dpcm->substream->pstr->pcm->device;
196 if (dpcm->substream->stream == SNDRV_PCM_STREAM_PLAYBACK)
198 return &dpcm->loopback->setup[dpcm->substream->number][device];
201 static inline unsigned int get_notify(struct loopback_pcm *dpcm)
203 return get_setup(dpcm)->notify;
206 static inline unsigned int get_rate_shift(struct loopback_pcm *dpcm)
208 return get_setup(dpcm)->rate_shift;
211 /* call in cable->lock */
212 static int loopback_jiffies_timer_start(struct loopback_pcm *dpcm)
215 unsigned int rate_shift = get_rate_shift(dpcm);
217 if (rate_shift != dpcm->pcm_rate_shift) {
218 dpcm->pcm_rate_shift = rate_shift;
219 dpcm->period_size_frac = frac_pos(dpcm, dpcm->pcm_period_size);
221 if (dpcm->period_size_frac <= dpcm->irq_pos) {
222 dpcm->irq_pos %= dpcm->period_size_frac;
223 dpcm->period_update_pending = 1;
225 tick = dpcm->period_size_frac - dpcm->irq_pos;
226 tick = DIV_ROUND_UP(tick, dpcm->pcm_bps);
227 mod_timer(&dpcm->timer, jiffies + tick);
232 /* call in cable->lock */
233 static int loopback_snd_timer_start(struct loopback_pcm *dpcm)
235 struct loopback_cable *cable = dpcm->cable;
238 /* Loopback device has to use same period as timer card. Therefore
239 * wake up for each snd_pcm_period_elapsed() call of timer card.
241 err = snd_timer_start(cable->snd_timer.instance, 1);
243 /* do not report error if trying to start but already
244 * running. For example called by opposite substream
250 pcm_err(dpcm->substream->pcm,
251 "snd_timer_start(%d,%d,%d) failed with %d",
252 cable->snd_timer.id.card,
253 cable->snd_timer.id.device,
254 cable->snd_timer.id.subdevice,
261 /* call in cable->lock */
262 static inline int loopback_jiffies_timer_stop(struct loopback_pcm *dpcm)
264 del_timer(&dpcm->timer);
265 dpcm->timer.expires = 0;
270 /* call in cable->lock */
271 static int loopback_snd_timer_stop(struct loopback_pcm *dpcm)
273 struct loopback_cable *cable = dpcm->cable;
276 /* only stop if both devices (playback and capture) are not running */
277 if (cable->running ^ cable->pause)
280 err = snd_timer_stop(cable->snd_timer.instance);
282 pcm_err(dpcm->substream->pcm,
283 "snd_timer_stop(%d,%d,%d) failed with %d",
284 cable->snd_timer.id.card,
285 cable->snd_timer.id.device,
286 cable->snd_timer.id.subdevice,
293 static inline int loopback_jiffies_timer_stop_sync(struct loopback_pcm *dpcm)
295 del_timer_sync(&dpcm->timer);
300 /* call in loopback->cable_lock */
301 static int loopback_snd_timer_close_cable(struct loopback_pcm *dpcm)
303 struct loopback_cable *cable = dpcm->cable;
305 /* snd_timer was not opened */
306 if (!cable->snd_timer.instance)
309 /* will only be called from free_cable() when other stream was
310 * already closed. Other stream cannot be reopened as long as
311 * loopback->cable_lock is locked. Therefore no need to lock
314 snd_timer_close(cable->snd_timer.instance);
316 /* wait till drain work has finished if requested */
317 cancel_work_sync(&cable->snd_timer.event_work);
319 snd_timer_instance_free(cable->snd_timer.instance);
320 memset(&cable->snd_timer, 0, sizeof(cable->snd_timer));
325 static bool is_access_interleaved(snd_pcm_access_t access)
328 case SNDRV_PCM_ACCESS_MMAP_INTERLEAVED:
329 case SNDRV_PCM_ACCESS_RW_INTERLEAVED:
336 static int loopback_check_format(struct loopback_cable *cable, int stream)
338 struct snd_pcm_runtime *runtime, *cruntime;
339 struct loopback_setup *setup;
340 struct snd_card *card;
343 if (cable->valid != CABLE_VALID_BOTH) {
344 if (stream == SNDRV_PCM_STREAM_PLAYBACK)
348 runtime = cable->streams[SNDRV_PCM_STREAM_PLAYBACK]->
350 cruntime = cable->streams[SNDRV_PCM_STREAM_CAPTURE]->
352 check = runtime->format != cruntime->format ||
353 runtime->rate != cruntime->rate ||
354 runtime->channels != cruntime->channels ||
355 is_access_interleaved(runtime->access) !=
356 is_access_interleaved(cruntime->access);
359 if (stream == SNDRV_PCM_STREAM_CAPTURE) {
362 snd_pcm_stop(cable->streams[SNDRV_PCM_STREAM_CAPTURE]->
363 substream, SNDRV_PCM_STATE_DRAINING);
365 runtime = cable->streams[SNDRV_PCM_STREAM_PLAYBACK]->
367 setup = get_setup(cable->streams[SNDRV_PCM_STREAM_PLAYBACK]);
368 card = cable->streams[SNDRV_PCM_STREAM_PLAYBACK]->loopback->card;
369 if (setup->format != runtime->format) {
370 snd_ctl_notify(card, SNDRV_CTL_EVENT_MASK_VALUE,
372 setup->format = runtime->format;
374 if (setup->rate != runtime->rate) {
375 snd_ctl_notify(card, SNDRV_CTL_EVENT_MASK_VALUE,
377 setup->rate = runtime->rate;
379 if (setup->channels != runtime->channels) {
380 snd_ctl_notify(card, SNDRV_CTL_EVENT_MASK_VALUE,
381 &setup->channels_id);
382 setup->channels = runtime->channels;
384 if (is_access_interleaved(setup->access) !=
385 is_access_interleaved(runtime->access)) {
386 snd_ctl_notify(card, SNDRV_CTL_EVENT_MASK_VALUE,
388 setup->access = runtime->access;
394 static void loopback_active_notify(struct loopback_pcm *dpcm)
396 snd_ctl_notify(dpcm->loopback->card,
397 SNDRV_CTL_EVENT_MASK_VALUE,
398 &get_setup(dpcm)->active_id);
401 static int loopback_trigger(struct snd_pcm_substream *substream, int cmd)
403 struct snd_pcm_runtime *runtime = substream->runtime;
404 struct loopback_pcm *dpcm = runtime->private_data;
405 struct loopback_cable *cable = dpcm->cable;
406 int err = 0, stream = 1 << substream->stream;
409 case SNDRV_PCM_TRIGGER_START:
410 err = loopback_check_format(cable, substream->stream);
413 dpcm->last_jiffies = jiffies;
414 dpcm->pcm_rate_shift = 0;
415 dpcm->last_drift = 0;
416 spin_lock(&cable->lock);
417 cable->running |= stream;
418 cable->pause &= ~stream;
419 err = cable->ops->start(dpcm);
420 spin_unlock(&cable->lock);
421 if (substream->stream == SNDRV_PCM_STREAM_PLAYBACK)
422 loopback_active_notify(dpcm);
424 case SNDRV_PCM_TRIGGER_STOP:
425 spin_lock(&cable->lock);
426 cable->running &= ~stream;
427 cable->pause &= ~stream;
428 err = cable->ops->stop(dpcm);
429 spin_unlock(&cable->lock);
430 if (substream->stream == SNDRV_PCM_STREAM_PLAYBACK)
431 loopback_active_notify(dpcm);
433 case SNDRV_PCM_TRIGGER_PAUSE_PUSH:
434 case SNDRV_PCM_TRIGGER_SUSPEND:
435 spin_lock(&cable->lock);
436 cable->pause |= stream;
437 err = cable->ops->stop(dpcm);
438 spin_unlock(&cable->lock);
439 if (substream->stream == SNDRV_PCM_STREAM_PLAYBACK)
440 loopback_active_notify(dpcm);
442 case SNDRV_PCM_TRIGGER_PAUSE_RELEASE:
443 case SNDRV_PCM_TRIGGER_RESUME:
444 spin_lock(&cable->lock);
445 dpcm->last_jiffies = jiffies;
446 cable->pause &= ~stream;
447 err = cable->ops->start(dpcm);
448 spin_unlock(&cable->lock);
449 if (substream->stream == SNDRV_PCM_STREAM_PLAYBACK)
450 loopback_active_notify(dpcm);
458 static void params_change(struct snd_pcm_substream *substream)
460 struct snd_pcm_runtime *runtime = substream->runtime;
461 struct loopback_pcm *dpcm = runtime->private_data;
462 struct loopback_cable *cable = dpcm->cable;
464 cable->hw.formats = pcm_format_to_bits(runtime->format);
465 cable->hw.rate_min = runtime->rate;
466 cable->hw.rate_max = runtime->rate;
467 cable->hw.channels_min = runtime->channels;
468 cable->hw.channels_max = runtime->channels;
470 if (cable->snd_timer.instance) {
471 cable->hw.period_bytes_min =
472 frames_to_bytes(runtime, runtime->period_size);
473 cable->hw.period_bytes_max = cable->hw.period_bytes_min;
478 static int loopback_prepare(struct snd_pcm_substream *substream)
480 struct snd_pcm_runtime *runtime = substream->runtime;
481 struct loopback_pcm *dpcm = runtime->private_data;
482 struct loopback_cable *cable = dpcm->cable;
483 int err, bps, salign;
485 if (cable->ops->stop_sync) {
486 err = cable->ops->stop_sync(dpcm);
491 salign = (snd_pcm_format_physical_width(runtime->format) *
492 runtime->channels) / 8;
493 bps = salign * runtime->rate;
494 if (bps <= 0 || salign <= 0)
498 dpcm->pcm_buffer_size = frames_to_bytes(runtime, runtime->buffer_size);
499 dpcm->channel_buf_n = dpcm->pcm_buffer_size / runtime->channels;
500 if (substream->stream == SNDRV_PCM_STREAM_CAPTURE) {
501 /* clear capture buffer */
502 dpcm->silent_size = dpcm->pcm_buffer_size;
503 snd_pcm_format_set_silence(runtime->format, runtime->dma_area,
504 runtime->buffer_size * runtime->channels);
508 dpcm->period_update_pending = 0;
510 dpcm->pcm_salign = salign;
511 dpcm->pcm_period_size = frames_to_bytes(runtime, runtime->period_size);
513 mutex_lock(&dpcm->loopback->cable_lock);
514 if (!(cable->valid & ~(1 << substream->stream)) ||
515 (get_setup(dpcm)->notify &&
516 substream->stream == SNDRV_PCM_STREAM_PLAYBACK))
517 params_change(substream);
518 cable->valid |= 1 << substream->stream;
519 mutex_unlock(&dpcm->loopback->cable_lock);
524 static void clear_capture_buf(struct loopback_pcm *dpcm, unsigned int bytes)
526 struct snd_pcm_runtime *runtime = dpcm->substream->runtime;
527 char *dst = runtime->dma_area;
528 unsigned int dst_off = dpcm->buf_pos;
530 if (dpcm->silent_size >= dpcm->pcm_buffer_size)
532 if (dpcm->silent_size + bytes > dpcm->pcm_buffer_size)
533 bytes = dpcm->pcm_buffer_size - dpcm->silent_size;
536 unsigned int size = bytes;
537 if (dst_off + size > dpcm->pcm_buffer_size)
538 size = dpcm->pcm_buffer_size - dst_off;
539 snd_pcm_format_set_silence(runtime->format, dst + dst_off,
540 bytes_to_frames(runtime, size) *
542 dpcm->silent_size += size;
550 static void copy_play_buf_part_n(struct loopback_pcm *play, struct loopback_pcm *capt,
551 unsigned int size, unsigned int src_off, unsigned int dst_off)
553 unsigned int channels = capt->substream->runtime->channels;
554 unsigned int size_p_ch = size / channels;
555 unsigned int src_off_ch = src_off / channels;
556 unsigned int dst_off_ch = dst_off / channels;
559 for (i = 0; i < channels; i++) {
560 memcpy(capt->substream->runtime->dma_area + capt->channel_buf_n * i + dst_off_ch,
561 play->substream->runtime->dma_area + play->channel_buf_n * i + src_off_ch,
566 static void copy_play_buf(struct loopback_pcm *play,
567 struct loopback_pcm *capt,
570 struct snd_pcm_runtime *runtime = play->substream->runtime;
571 char *src = runtime->dma_area;
572 char *dst = capt->substream->runtime->dma_area;
573 unsigned int src_off = play->buf_pos;
574 unsigned int dst_off = capt->buf_pos;
575 unsigned int clear_bytes = 0;
577 /* check if playback is draining, trim the capture copy size
578 * when our pointer is at the end of playback ring buffer */
579 if (runtime->state == SNDRV_PCM_STATE_DRAINING &&
580 snd_pcm_playback_hw_avail(runtime) < runtime->buffer_size) {
581 snd_pcm_uframes_t appl_ptr, appl_ptr1, diff;
582 appl_ptr = appl_ptr1 = runtime->control->appl_ptr;
583 appl_ptr1 -= appl_ptr1 % runtime->buffer_size;
584 appl_ptr1 += play->buf_pos / play->pcm_salign;
585 if (appl_ptr < appl_ptr1)
586 appl_ptr1 -= runtime->buffer_size;
587 diff = (appl_ptr - appl_ptr1) * play->pcm_salign;
589 clear_bytes = bytes - diff;
595 unsigned int size = bytes;
596 if (src_off + size > play->pcm_buffer_size)
597 size = play->pcm_buffer_size - src_off;
598 if (dst_off + size > capt->pcm_buffer_size)
599 size = capt->pcm_buffer_size - dst_off;
600 if (!is_access_interleaved(runtime->access))
601 copy_play_buf_part_n(play, capt, size, src_off, dst_off);
603 memcpy(dst + dst_off, src + src_off, size);
604 capt->silent_size = 0;
608 src_off = (src_off + size) % play->pcm_buffer_size;
609 dst_off = (dst_off + size) % capt->pcm_buffer_size;
612 if (clear_bytes > 0) {
613 clear_capture_buf(capt, clear_bytes);
614 capt->silent_size = 0;
618 static inline unsigned int bytepos_delta(struct loopback_pcm *dpcm,
619 unsigned int jiffies_delta)
621 unsigned long last_pos;
624 last_pos = byte_pos(dpcm, dpcm->irq_pos);
625 dpcm->irq_pos += jiffies_delta * dpcm->pcm_bps;
626 delta = byte_pos(dpcm, dpcm->irq_pos) - last_pos;
627 if (delta >= dpcm->last_drift)
628 delta -= dpcm->last_drift;
629 dpcm->last_drift = 0;
630 if (dpcm->irq_pos >= dpcm->period_size_frac) {
631 dpcm->irq_pos %= dpcm->period_size_frac;
632 dpcm->period_update_pending = 1;
637 static inline void bytepos_finish(struct loopback_pcm *dpcm,
640 dpcm->buf_pos += delta;
641 dpcm->buf_pos %= dpcm->pcm_buffer_size;
644 /* call in cable->lock */
645 static unsigned int loopback_jiffies_timer_pos_update
646 (struct loopback_cable *cable)
648 struct loopback_pcm *dpcm_play =
649 cable->streams[SNDRV_PCM_STREAM_PLAYBACK];
650 struct loopback_pcm *dpcm_capt =
651 cable->streams[SNDRV_PCM_STREAM_CAPTURE];
652 unsigned long delta_play = 0, delta_capt = 0, cur_jiffies;
653 unsigned int running, count1, count2;
655 cur_jiffies = jiffies;
656 running = cable->running ^ cable->pause;
657 if (running & (1 << SNDRV_PCM_STREAM_PLAYBACK)) {
658 delta_play = cur_jiffies - dpcm_play->last_jiffies;
659 dpcm_play->last_jiffies += delta_play;
662 if (running & (1 << SNDRV_PCM_STREAM_CAPTURE)) {
663 delta_capt = cur_jiffies - dpcm_capt->last_jiffies;
664 dpcm_capt->last_jiffies += delta_capt;
667 if (delta_play == 0 && delta_capt == 0)
670 if (delta_play > delta_capt) {
671 count1 = bytepos_delta(dpcm_play, delta_play - delta_capt);
672 bytepos_finish(dpcm_play, count1);
673 delta_play = delta_capt;
674 } else if (delta_play < delta_capt) {
675 count1 = bytepos_delta(dpcm_capt, delta_capt - delta_play);
676 clear_capture_buf(dpcm_capt, count1);
677 bytepos_finish(dpcm_capt, count1);
678 delta_capt = delta_play;
681 if (delta_play == 0 && delta_capt == 0)
684 /* note delta_capt == delta_play at this moment */
685 count1 = bytepos_delta(dpcm_play, delta_play);
686 count2 = bytepos_delta(dpcm_capt, delta_capt);
687 if (count1 < count2) {
688 dpcm_capt->last_drift = count2 - count1;
690 } else if (count1 > count2) {
691 dpcm_play->last_drift = count1 - count2;
693 copy_play_buf(dpcm_play, dpcm_capt, count1);
694 bytepos_finish(dpcm_play, count1);
695 bytepos_finish(dpcm_capt, count1);
700 static void loopback_jiffies_timer_function(struct timer_list *t)
702 struct loopback_pcm *dpcm = from_timer(dpcm, t, timer);
705 spin_lock_irqsave(&dpcm->cable->lock, flags);
706 if (loopback_jiffies_timer_pos_update(dpcm->cable) &
707 (1 << dpcm->substream->stream)) {
708 loopback_jiffies_timer_start(dpcm);
709 if (dpcm->period_update_pending) {
710 dpcm->period_update_pending = 0;
711 spin_unlock_irqrestore(&dpcm->cable->lock, flags);
712 /* need to unlock before calling below */
713 snd_pcm_period_elapsed(dpcm->substream);
717 spin_unlock_irqrestore(&dpcm->cable->lock, flags);
720 /* call in cable->lock */
721 static int loopback_snd_timer_check_resolution(struct snd_pcm_runtime *runtime,
722 unsigned long resolution)
724 if (resolution != runtime->timer_resolution) {
725 struct loopback_pcm *dpcm = runtime->private_data;
726 struct loopback_cable *cable = dpcm->cable;
727 /* Worst case estimation of possible values for resolution
728 * resolution <= (512 * 1024) frames / 8kHz in nsec
729 * resolution <= 65.536.000.000 nsec
731 * period_size <= 65.536.000.000 nsec / 1000nsec/usec * 192kHz +
733 * period_size <= 12.582.912.000.000 <64bit
734 * / 1.000.000 usec/sec
736 snd_pcm_uframes_t period_size_usec =
737 resolution / 1000 * runtime->rate;
738 /* round to nearest sample rate */
739 snd_pcm_uframes_t period_size =
740 (period_size_usec + 500 * 1000) / (1000 * 1000);
742 pcm_err(dpcm->substream->pcm,
743 "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.",
744 runtime->period_size, resolution, period_size,
745 cable->snd_timer.id.card,
746 cable->snd_timer.id.device,
747 cable->snd_timer.id.subdevice,
754 static void loopback_snd_timer_period_elapsed(struct loopback_cable *cable,
756 unsigned long resolution)
758 struct loopback_pcm *dpcm_play, *dpcm_capt;
759 struct snd_pcm_substream *substream_play, *substream_capt;
760 struct snd_pcm_runtime *valid_runtime;
761 unsigned int running, elapsed_bytes;
764 spin_lock_irqsave(&cable->lock, flags);
765 running = cable->running ^ cable->pause;
766 /* no need to do anything if no stream is running */
768 spin_unlock_irqrestore(&cable->lock, flags);
772 dpcm_play = cable->streams[SNDRV_PCM_STREAM_PLAYBACK];
773 dpcm_capt = cable->streams[SNDRV_PCM_STREAM_CAPTURE];
775 if (event == SNDRV_TIMER_EVENT_MSTOP) {
777 dpcm_play->substream->runtime->state !=
778 SNDRV_PCM_STATE_DRAINING) {
779 spin_unlock_irqrestore(&cable->lock, flags);
784 substream_play = (running & (1 << SNDRV_PCM_STREAM_PLAYBACK)) ?
785 dpcm_play->substream : NULL;
786 substream_capt = (running & (1 << SNDRV_PCM_STREAM_CAPTURE)) ?
787 dpcm_capt->substream : NULL;
788 valid_runtime = (running & (1 << SNDRV_PCM_STREAM_PLAYBACK)) ?
789 dpcm_play->substream->runtime :
790 dpcm_capt->substream->runtime;
792 /* resolution is only valid for SNDRV_TIMER_EVENT_TICK events */
793 if (event == SNDRV_TIMER_EVENT_TICK) {
794 /* The hardware rules guarantee that playback and capture period
795 * are the same. Therefore only one device has to be checked
798 if (loopback_snd_timer_check_resolution(valid_runtime,
800 spin_unlock_irqrestore(&cable->lock, flags);
802 snd_pcm_stop_xrun(substream_play);
804 snd_pcm_stop_xrun(substream_capt);
809 elapsed_bytes = frames_to_bytes(valid_runtime,
810 valid_runtime->period_size);
811 /* The same timer interrupt is used for playback and capture device */
812 if ((running & (1 << SNDRV_PCM_STREAM_PLAYBACK)) &&
813 (running & (1 << SNDRV_PCM_STREAM_CAPTURE))) {
814 copy_play_buf(dpcm_play, dpcm_capt, elapsed_bytes);
815 bytepos_finish(dpcm_play, elapsed_bytes);
816 bytepos_finish(dpcm_capt, elapsed_bytes);
817 } else if (running & (1 << SNDRV_PCM_STREAM_PLAYBACK)) {
818 bytepos_finish(dpcm_play, elapsed_bytes);
819 } else if (running & (1 << SNDRV_PCM_STREAM_CAPTURE)) {
820 clear_capture_buf(dpcm_capt, elapsed_bytes);
821 bytepos_finish(dpcm_capt, elapsed_bytes);
823 spin_unlock_irqrestore(&cable->lock, flags);
826 snd_pcm_period_elapsed(substream_play);
828 snd_pcm_period_elapsed(substream_capt);
831 static void loopback_snd_timer_function(struct snd_timer_instance *timeri,
832 unsigned long resolution,
835 struct loopback_cable *cable = timeri->callback_data;
837 loopback_snd_timer_period_elapsed(cable, SNDRV_TIMER_EVENT_TICK,
841 static void loopback_snd_timer_work(struct work_struct *work)
843 struct loopback_cable *cable;
845 cable = container_of(work, struct loopback_cable, snd_timer.event_work);
846 loopback_snd_timer_period_elapsed(cable, SNDRV_TIMER_EVENT_MSTOP, 0);
849 static void loopback_snd_timer_event(struct snd_timer_instance *timeri,
851 struct timespec64 *tstamp,
852 unsigned long resolution)
854 /* Do not lock cable->lock here because timer->lock is already hold.
855 * There are other functions which first lock cable->lock and than
858 * spin_lock(&cable->lock)
859 * loopback_snd_timer_start()
861 * spin_lock(&timer->lock)
862 * Therefore when using the oposit order of locks here it could result
866 if (event == SNDRV_TIMER_EVENT_MSTOP) {
867 struct loopback_cable *cable = timeri->callback_data;
869 /* sound card of the timer was stopped. Therefore there will not
870 * be any further timer callbacks. Due to this forward audio
871 * data from here if in draining state. When still in running
872 * state the streaming will be aborted by the usual timeout. It
873 * should not be aborted here because may be the timer sound
874 * card does only a recovery and the timer is back soon.
875 * This work triggers loopback_snd_timer_work()
877 schedule_work(&cable->snd_timer.event_work);
881 static void loopback_jiffies_timer_dpcm_info(struct loopback_pcm *dpcm,
882 struct snd_info_buffer *buffer)
884 snd_iprintf(buffer, " update_pending:\t%u\n",
885 dpcm->period_update_pending);
886 snd_iprintf(buffer, " irq_pos:\t\t%u\n", dpcm->irq_pos);
887 snd_iprintf(buffer, " period_frac:\t%u\n", dpcm->period_size_frac);
888 snd_iprintf(buffer, " last_jiffies:\t%lu (%lu)\n",
889 dpcm->last_jiffies, jiffies);
890 snd_iprintf(buffer, " timer_expires:\t%lu\n", dpcm->timer.expires);
893 static void loopback_snd_timer_dpcm_info(struct loopback_pcm *dpcm,
894 struct snd_info_buffer *buffer)
896 struct loopback_cable *cable = dpcm->cable;
898 snd_iprintf(buffer, " sound timer:\thw:%d,%d,%d\n",
899 cable->snd_timer.id.card,
900 cable->snd_timer.id.device,
901 cable->snd_timer.id.subdevice);
902 snd_iprintf(buffer, " timer open:\t\t%s\n",
903 (cable->snd_timer.stream == SNDRV_PCM_STREAM_CAPTURE) ?
904 "capture" : "playback");
907 static snd_pcm_uframes_t loopback_pointer(struct snd_pcm_substream *substream)
909 struct snd_pcm_runtime *runtime = substream->runtime;
910 struct loopback_pcm *dpcm = runtime->private_data;
911 snd_pcm_uframes_t pos;
913 spin_lock(&dpcm->cable->lock);
914 if (dpcm->cable->ops->pos_update)
915 dpcm->cable->ops->pos_update(dpcm->cable);
917 spin_unlock(&dpcm->cable->lock);
918 return bytes_to_frames(runtime, pos);
921 static const struct snd_pcm_hardware loopback_pcm_hardware =
923 .info = (SNDRV_PCM_INFO_INTERLEAVED | SNDRV_PCM_INFO_MMAP |
924 SNDRV_PCM_INFO_MMAP_VALID | SNDRV_PCM_INFO_PAUSE |
925 SNDRV_PCM_INFO_RESUME | SNDRV_PCM_INFO_NONINTERLEAVED),
926 .formats = (SNDRV_PCM_FMTBIT_S16_LE | SNDRV_PCM_FMTBIT_S16_BE |
927 SNDRV_PCM_FMTBIT_S24_LE | SNDRV_PCM_FMTBIT_S24_BE |
928 SNDRV_PCM_FMTBIT_S24_3LE | SNDRV_PCM_FMTBIT_S24_3BE |
929 SNDRV_PCM_FMTBIT_S32_LE | SNDRV_PCM_FMTBIT_S32_BE |
930 SNDRV_PCM_FMTBIT_FLOAT_LE | SNDRV_PCM_FMTBIT_FLOAT_BE),
931 .rates = SNDRV_PCM_RATE_CONTINUOUS | SNDRV_PCM_RATE_8000_192000,
936 .buffer_bytes_max = 2 * 1024 * 1024,
937 .period_bytes_min = 64,
938 /* note check overflow in frac_pos() using pcm_rate_shift before
939 changing period_bytes_max value */
940 .period_bytes_max = 1024 * 1024,
946 static void loopback_runtime_free(struct snd_pcm_runtime *runtime)
948 struct loopback_pcm *dpcm = runtime->private_data;
952 static int loopback_hw_free(struct snd_pcm_substream *substream)
954 struct snd_pcm_runtime *runtime = substream->runtime;
955 struct loopback_pcm *dpcm = runtime->private_data;
956 struct loopback_cable *cable = dpcm->cable;
958 mutex_lock(&dpcm->loopback->cable_lock);
959 cable->valid &= ~(1 << substream->stream);
960 mutex_unlock(&dpcm->loopback->cable_lock);
964 static unsigned int get_cable_index(struct snd_pcm_substream *substream)
966 if (!substream->pcm->device)
967 return substream->stream;
969 return !substream->stream;
972 static int rule_format(struct snd_pcm_hw_params *params,
973 struct snd_pcm_hw_rule *rule)
975 struct loopback_pcm *dpcm = rule->private;
976 struct loopback_cable *cable = dpcm->cable;
980 mutex_lock(&dpcm->loopback->cable_lock);
981 m.bits[0] = (u_int32_t)cable->hw.formats;
982 m.bits[1] = (u_int32_t)(cable->hw.formats >> 32);
983 mutex_unlock(&dpcm->loopback->cable_lock);
984 return snd_mask_refine(hw_param_mask(params, rule->var), &m);
987 static int rule_rate(struct snd_pcm_hw_params *params,
988 struct snd_pcm_hw_rule *rule)
990 struct loopback_pcm *dpcm = rule->private;
991 struct loopback_cable *cable = dpcm->cable;
992 struct snd_interval t;
994 mutex_lock(&dpcm->loopback->cable_lock);
995 t.min = cable->hw.rate_min;
996 t.max = cable->hw.rate_max;
997 mutex_unlock(&dpcm->loopback->cable_lock);
998 t.openmin = t.openmax = 0;
1000 return snd_interval_refine(hw_param_interval(params, rule->var), &t);
1003 static int rule_channels(struct snd_pcm_hw_params *params,
1004 struct snd_pcm_hw_rule *rule)
1006 struct loopback_pcm *dpcm = rule->private;
1007 struct loopback_cable *cable = dpcm->cable;
1008 struct snd_interval t;
1010 mutex_lock(&dpcm->loopback->cable_lock);
1011 t.min = cable->hw.channels_min;
1012 t.max = cable->hw.channels_max;
1013 mutex_unlock(&dpcm->loopback->cable_lock);
1014 t.openmin = t.openmax = 0;
1016 return snd_interval_refine(hw_param_interval(params, rule->var), &t);
1019 static int rule_period_bytes(struct snd_pcm_hw_params *params,
1020 struct snd_pcm_hw_rule *rule)
1022 struct loopback_pcm *dpcm = rule->private;
1023 struct loopback_cable *cable = dpcm->cable;
1024 struct snd_interval t;
1026 mutex_lock(&dpcm->loopback->cable_lock);
1027 t.min = cable->hw.period_bytes_min;
1028 t.max = cable->hw.period_bytes_max;
1029 mutex_unlock(&dpcm->loopback->cable_lock);
1033 return snd_interval_refine(hw_param_interval(params, rule->var), &t);
1036 static void free_cable(struct snd_pcm_substream *substream)
1038 struct loopback *loopback = substream->private_data;
1039 int dev = get_cable_index(substream);
1040 struct loopback_cable *cable;
1042 cable = loopback->cables[substream->number][dev];
1045 if (cable->streams[!substream->stream]) {
1046 /* other stream is still alive */
1047 spin_lock_irq(&cable->lock);
1048 cable->streams[substream->stream] = NULL;
1049 spin_unlock_irq(&cable->lock);
1051 struct loopback_pcm *dpcm = substream->runtime->private_data;
1053 if (cable->ops && cable->ops->close_cable && dpcm)
1054 cable->ops->close_cable(dpcm);
1055 /* free the cable */
1056 loopback->cables[substream->number][dev] = NULL;
1061 static int loopback_jiffies_timer_open(struct loopback_pcm *dpcm)
1063 timer_setup(&dpcm->timer, loopback_jiffies_timer_function, 0);
1068 static const struct loopback_ops loopback_jiffies_timer_ops = {
1069 .open = loopback_jiffies_timer_open,
1070 .start = loopback_jiffies_timer_start,
1071 .stop = loopback_jiffies_timer_stop,
1072 .stop_sync = loopback_jiffies_timer_stop_sync,
1073 .close_substream = loopback_jiffies_timer_stop_sync,
1074 .pos_update = loopback_jiffies_timer_pos_update,
1075 .dpcm_info = loopback_jiffies_timer_dpcm_info,
1078 static int loopback_parse_timer_id(const char *str,
1079 struct snd_timer_id *tid)
1081 /* [<pref>:](<card name>|<card idx>)[{.,}<dev idx>[{.,}<subdev idx>]] */
1082 const char * const sep_dev = ".,";
1083 const char * const sep_pref = ":";
1084 const char *name = str;
1085 char *sep, save = '\0';
1086 int card_idx = 0, dev = 0, subdev = 0;
1089 sep = strpbrk(str, sep_pref);
1092 sep = strpbrk(name, sep_dev);
1097 err = kstrtoint(name, 0, &card_idx);
1098 if (err == -EINVAL) {
1099 /* Must be the name, not number */
1100 for (card_idx = 0; card_idx < snd_ecards_limit; card_idx++) {
1101 struct snd_card *card = snd_card_ref(card_idx);
1104 if (!strcmp(card->id, name))
1106 snd_card_unref(card);
1115 char *sep2, save2 = '\0';
1117 sep2 = strpbrk(sep + 1, sep_dev);
1122 err = kstrtoint(sep + 1, 0, &dev);
1126 err = kstrtoint(sep2 + 1, 0, &subdev);
1131 tid->card = card_idx;
1133 tid->subdevice = subdev;
1138 /* call in loopback->cable_lock */
1139 static int loopback_snd_timer_open(struct loopback_pcm *dpcm)
1142 struct snd_timer_id tid = {
1143 .dev_class = SNDRV_TIMER_CLASS_PCM,
1144 .dev_sclass = SNDRV_TIMER_SCLASS_APPLICATION,
1146 struct snd_timer_instance *timeri;
1147 struct loopback_cable *cable = dpcm->cable;
1149 /* check if timer was already opened. It is only opened once
1150 * per playback and capture subdevice (aka cable).
1152 if (cable->snd_timer.instance)
1155 err = loopback_parse_timer_id(dpcm->loopback->timer_source, &tid);
1157 pcm_err(dpcm->substream->pcm,
1158 "Parsing timer source \'%s\' failed with %d",
1159 dpcm->loopback->timer_source, err);
1163 cable->snd_timer.stream = dpcm->substream->stream;
1164 cable->snd_timer.id = tid;
1166 timeri = snd_timer_instance_new(dpcm->loopback->card->id);
1171 /* The callback has to be called from another work. If
1172 * SNDRV_TIMER_IFLG_FAST is specified it will be called from the
1173 * snd_pcm_period_elapsed() call of the selected sound card.
1174 * snd_pcm_period_elapsed() helds snd_pcm_stream_lock_irqsave().
1175 * Due to our callback loopback_snd_timer_function() also calls
1176 * snd_pcm_period_elapsed() which calls snd_pcm_stream_lock_irqsave().
1177 * This would end up in a dead lock.
1179 timeri->flags |= SNDRV_TIMER_IFLG_AUTO;
1180 timeri->callback = loopback_snd_timer_function;
1181 timeri->callback_data = (void *)cable;
1182 timeri->ccallback = loopback_snd_timer_event;
1184 /* initialise a work used for draining */
1185 INIT_WORK(&cable->snd_timer.event_work, loopback_snd_timer_work);
1187 /* The mutex loopback->cable_lock is kept locked.
1188 * Therefore snd_timer_open() cannot be called a second time
1189 * by the other device of the same cable.
1190 * Therefore the following issue cannot happen:
1191 * [proc1] Call loopback_timer_open() ->
1192 * Unlock cable->lock for snd_timer_close/open() call
1193 * [proc2] Call loopback_timer_open() -> snd_timer_open(),
1195 * [proc1] Call snd_timer_open() and overwrite running timer
1198 err = snd_timer_open(timeri, &cable->snd_timer.id, current->pid);
1200 pcm_err(dpcm->substream->pcm,
1201 "snd_timer_open (%d,%d,%d) failed with %d",
1202 cable->snd_timer.id.card,
1203 cable->snd_timer.id.device,
1204 cable->snd_timer.id.subdevice,
1206 snd_timer_instance_free(timeri);
1210 cable->snd_timer.instance = timeri;
1216 /* stop_sync() is not required for sound timer because it does not need to be
1217 * restarted in loopback_prepare() on Xrun recovery
1219 static const struct loopback_ops loopback_snd_timer_ops = {
1220 .open = loopback_snd_timer_open,
1221 .start = loopback_snd_timer_start,
1222 .stop = loopback_snd_timer_stop,
1223 .close_cable = loopback_snd_timer_close_cable,
1224 .dpcm_info = loopback_snd_timer_dpcm_info,
1227 static int loopback_open(struct snd_pcm_substream *substream)
1229 struct snd_pcm_runtime *runtime = substream->runtime;
1230 struct loopback *loopback = substream->private_data;
1231 struct loopback_pcm *dpcm;
1232 struct loopback_cable *cable = NULL;
1234 int dev = get_cable_index(substream);
1236 mutex_lock(&loopback->cable_lock);
1237 dpcm = kzalloc(sizeof(*dpcm), GFP_KERNEL);
1242 dpcm->loopback = loopback;
1243 dpcm->substream = substream;
1245 cable = loopback->cables[substream->number][dev];
1247 cable = kzalloc(sizeof(*cable), GFP_KERNEL);
1252 spin_lock_init(&cable->lock);
1253 cable->hw = loopback_pcm_hardware;
1254 if (loopback->timer_source)
1255 cable->ops = &loopback_snd_timer_ops;
1257 cable->ops = &loopback_jiffies_timer_ops;
1258 loopback->cables[substream->number][dev] = cable;
1260 dpcm->cable = cable;
1261 runtime->private_data = dpcm;
1263 if (cable->ops->open) {
1264 err = cable->ops->open(dpcm);
1269 snd_pcm_hw_constraint_integer(runtime, SNDRV_PCM_HW_PARAM_PERIODS);
1271 /* use dynamic rules based on actual runtime->hw values */
1272 /* note that the default rules created in the PCM midlevel code */
1273 /* are cached -> they do not reflect the actual state */
1274 err = snd_pcm_hw_rule_add(runtime, 0,
1275 SNDRV_PCM_HW_PARAM_FORMAT,
1277 SNDRV_PCM_HW_PARAM_FORMAT, -1);
1280 err = snd_pcm_hw_rule_add(runtime, 0,
1281 SNDRV_PCM_HW_PARAM_RATE,
1283 SNDRV_PCM_HW_PARAM_RATE, -1);
1286 err = snd_pcm_hw_rule_add(runtime, 0,
1287 SNDRV_PCM_HW_PARAM_CHANNELS,
1288 rule_channels, dpcm,
1289 SNDRV_PCM_HW_PARAM_CHANNELS, -1);
1293 /* In case of sound timer the period time of both devices of the same
1294 * loop has to be the same.
1295 * This rule only takes effect if a sound timer was chosen
1297 if (cable->snd_timer.instance) {
1298 err = snd_pcm_hw_rule_add(runtime, 0,
1299 SNDRV_PCM_HW_PARAM_PERIOD_BYTES,
1300 rule_period_bytes, dpcm,
1301 SNDRV_PCM_HW_PARAM_PERIOD_BYTES, -1);
1306 /* loopback_runtime_free() has not to be called if kfree(dpcm) was
1307 * already called here. Otherwise it will end up with a double free.
1309 runtime->private_free = loopback_runtime_free;
1310 if (get_notify(dpcm))
1311 runtime->hw = loopback_pcm_hardware;
1313 runtime->hw = cable->hw;
1315 spin_lock_irq(&cable->lock);
1316 cable->streams[substream->stream] = dpcm;
1317 spin_unlock_irq(&cable->lock);
1321 free_cable(substream);
1324 mutex_unlock(&loopback->cable_lock);
1328 static int loopback_close(struct snd_pcm_substream *substream)
1330 struct loopback *loopback = substream->private_data;
1331 struct loopback_pcm *dpcm = substream->runtime->private_data;
1334 if (dpcm->cable->ops->close_substream)
1335 err = dpcm->cable->ops->close_substream(dpcm);
1336 mutex_lock(&loopback->cable_lock);
1337 free_cable(substream);
1338 mutex_unlock(&loopback->cable_lock);
1342 static const struct snd_pcm_ops loopback_pcm_ops = {
1343 .open = loopback_open,
1344 .close = loopback_close,
1345 .hw_free = loopback_hw_free,
1346 .prepare = loopback_prepare,
1347 .trigger = loopback_trigger,
1348 .pointer = loopback_pointer,
1351 static int loopback_pcm_new(struct loopback *loopback,
1352 int device, int substreams)
1354 struct snd_pcm *pcm;
1357 err = snd_pcm_new(loopback->card, "Loopback PCM", device,
1358 substreams, substreams, &pcm);
1361 snd_pcm_set_ops(pcm, SNDRV_PCM_STREAM_PLAYBACK, &loopback_pcm_ops);
1362 snd_pcm_set_ops(pcm, SNDRV_PCM_STREAM_CAPTURE, &loopback_pcm_ops);
1363 snd_pcm_set_managed_buffer_all(pcm, SNDRV_DMA_TYPE_VMALLOC, NULL, 0, 0);
1365 pcm->private_data = loopback;
1366 pcm->info_flags = 0;
1367 strcpy(pcm->name, "Loopback PCM");
1369 loopback->pcm[device] = pcm;
1373 static int loopback_rate_shift_info(struct snd_kcontrol *kcontrol,
1374 struct snd_ctl_elem_info *uinfo)
1376 uinfo->type = SNDRV_CTL_ELEM_TYPE_INTEGER;
1378 uinfo->value.integer.min = 80000;
1379 uinfo->value.integer.max = 120000;
1380 uinfo->value.integer.step = 1;
1384 static int loopback_rate_shift_get(struct snd_kcontrol *kcontrol,
1385 struct snd_ctl_elem_value *ucontrol)
1387 struct loopback *loopback = snd_kcontrol_chip(kcontrol);
1389 mutex_lock(&loopback->cable_lock);
1390 ucontrol->value.integer.value[0] =
1391 loopback->setup[kcontrol->id.subdevice]
1392 [kcontrol->id.device].rate_shift;
1393 mutex_unlock(&loopback->cable_lock);
1397 static int loopback_rate_shift_put(struct snd_kcontrol *kcontrol,
1398 struct snd_ctl_elem_value *ucontrol)
1400 struct loopback *loopback = snd_kcontrol_chip(kcontrol);
1404 val = ucontrol->value.integer.value[0];
1409 mutex_lock(&loopback->cable_lock);
1410 if (val != loopback->setup[kcontrol->id.subdevice]
1411 [kcontrol->id.device].rate_shift) {
1412 loopback->setup[kcontrol->id.subdevice]
1413 [kcontrol->id.device].rate_shift = val;
1416 mutex_unlock(&loopback->cable_lock);
1420 static int loopback_notify_get(struct snd_kcontrol *kcontrol,
1421 struct snd_ctl_elem_value *ucontrol)
1423 struct loopback *loopback = snd_kcontrol_chip(kcontrol);
1425 mutex_lock(&loopback->cable_lock);
1426 ucontrol->value.integer.value[0] =
1427 loopback->setup[kcontrol->id.subdevice]
1428 [kcontrol->id.device].notify;
1429 mutex_unlock(&loopback->cable_lock);
1433 static int loopback_notify_put(struct snd_kcontrol *kcontrol,
1434 struct snd_ctl_elem_value *ucontrol)
1436 struct loopback *loopback = snd_kcontrol_chip(kcontrol);
1440 val = ucontrol->value.integer.value[0] ? 1 : 0;
1441 mutex_lock(&loopback->cable_lock);
1442 if (val != loopback->setup[kcontrol->id.subdevice]
1443 [kcontrol->id.device].notify) {
1444 loopback->setup[kcontrol->id.subdevice]
1445 [kcontrol->id.device].notify = val;
1448 mutex_unlock(&loopback->cable_lock);
1452 static int loopback_active_get(struct snd_kcontrol *kcontrol,
1453 struct snd_ctl_elem_value *ucontrol)
1455 struct loopback *loopback = snd_kcontrol_chip(kcontrol);
1456 struct loopback_cable *cable;
1458 unsigned int val = 0;
1460 mutex_lock(&loopback->cable_lock);
1461 cable = loopback->cables[kcontrol->id.subdevice][kcontrol->id.device ^ 1];
1462 if (cable != NULL) {
1463 unsigned int running = cable->running ^ cable->pause;
1465 val = (running & (1 << SNDRV_PCM_STREAM_PLAYBACK)) ? 1 : 0;
1467 mutex_unlock(&loopback->cable_lock);
1468 ucontrol->value.integer.value[0] = val;
1472 static int loopback_format_info(struct snd_kcontrol *kcontrol,
1473 struct snd_ctl_elem_info *uinfo)
1475 uinfo->type = SNDRV_CTL_ELEM_TYPE_INTEGER;
1477 uinfo->value.integer.min = 0;
1478 uinfo->value.integer.max = (__force int)SNDRV_PCM_FORMAT_LAST;
1479 uinfo->value.integer.step = 1;
1483 static int loopback_format_get(struct snd_kcontrol *kcontrol,
1484 struct snd_ctl_elem_value *ucontrol)
1486 struct loopback *loopback = snd_kcontrol_chip(kcontrol);
1488 ucontrol->value.integer.value[0] =
1489 (__force int)loopback->setup[kcontrol->id.subdevice]
1490 [kcontrol->id.device].format;
1494 static int loopback_rate_info(struct snd_kcontrol *kcontrol,
1495 struct snd_ctl_elem_info *uinfo)
1497 uinfo->type = SNDRV_CTL_ELEM_TYPE_INTEGER;
1499 uinfo->value.integer.min = 0;
1500 uinfo->value.integer.max = 192000;
1501 uinfo->value.integer.step = 1;
1505 static int loopback_rate_get(struct snd_kcontrol *kcontrol,
1506 struct snd_ctl_elem_value *ucontrol)
1508 struct loopback *loopback = snd_kcontrol_chip(kcontrol);
1510 mutex_lock(&loopback->cable_lock);
1511 ucontrol->value.integer.value[0] =
1512 loopback->setup[kcontrol->id.subdevice]
1513 [kcontrol->id.device].rate;
1514 mutex_unlock(&loopback->cable_lock);
1518 static int loopback_channels_info(struct snd_kcontrol *kcontrol,
1519 struct snd_ctl_elem_info *uinfo)
1521 uinfo->type = SNDRV_CTL_ELEM_TYPE_INTEGER;
1523 uinfo->value.integer.min = 1;
1524 uinfo->value.integer.max = 1024;
1525 uinfo->value.integer.step = 1;
1529 static int loopback_channels_get(struct snd_kcontrol *kcontrol,
1530 struct snd_ctl_elem_value *ucontrol)
1532 struct loopback *loopback = snd_kcontrol_chip(kcontrol);
1534 mutex_lock(&loopback->cable_lock);
1535 ucontrol->value.integer.value[0] =
1536 loopback->setup[kcontrol->id.subdevice]
1537 [kcontrol->id.device].channels;
1538 mutex_unlock(&loopback->cable_lock);
1542 static int loopback_access_info(struct snd_kcontrol *kcontrol,
1543 struct snd_ctl_elem_info *uinfo)
1545 const char * const texts[] = {"Interleaved", "Non-interleaved"};
1547 return snd_ctl_enum_info(uinfo, 1, ARRAY_SIZE(texts), texts);
1550 static int loopback_access_get(struct snd_kcontrol *kcontrol,
1551 struct snd_ctl_elem_value *ucontrol)
1553 struct loopback *loopback = snd_kcontrol_chip(kcontrol);
1554 snd_pcm_access_t access;
1556 mutex_lock(&loopback->cable_lock);
1557 access = loopback->setup[kcontrol->id.subdevice][kcontrol->id.device].access;
1559 ucontrol->value.enumerated.item[0] = !is_access_interleaved(access);
1561 mutex_unlock(&loopback->cable_lock);
1565 static const struct snd_kcontrol_new loopback_controls[] = {
1567 .iface = SNDRV_CTL_ELEM_IFACE_PCM,
1568 .name = "PCM Rate Shift 100000",
1569 .info = loopback_rate_shift_info,
1570 .get = loopback_rate_shift_get,
1571 .put = loopback_rate_shift_put,
1574 .iface = SNDRV_CTL_ELEM_IFACE_PCM,
1575 .name = "PCM Notify",
1576 .info = snd_ctl_boolean_mono_info,
1577 .get = loopback_notify_get,
1578 .put = loopback_notify_put,
1580 #define ACTIVE_IDX 2
1582 .access = SNDRV_CTL_ELEM_ACCESS_READ,
1583 .iface = SNDRV_CTL_ELEM_IFACE_PCM,
1584 .name = "PCM Slave Active",
1585 .info = snd_ctl_boolean_mono_info,
1586 .get = loopback_active_get,
1588 #define FORMAT_IDX 3
1590 .access = SNDRV_CTL_ELEM_ACCESS_READ,
1591 .iface = SNDRV_CTL_ELEM_IFACE_PCM,
1592 .name = "PCM Slave Format",
1593 .info = loopback_format_info,
1594 .get = loopback_format_get
1598 .access = SNDRV_CTL_ELEM_ACCESS_READ,
1599 .iface = SNDRV_CTL_ELEM_IFACE_PCM,
1600 .name = "PCM Slave Rate",
1601 .info = loopback_rate_info,
1602 .get = loopback_rate_get
1604 #define CHANNELS_IDX 5
1606 .access = SNDRV_CTL_ELEM_ACCESS_READ,
1607 .iface = SNDRV_CTL_ELEM_IFACE_PCM,
1608 .name = "PCM Slave Channels",
1609 .info = loopback_channels_info,
1610 .get = loopback_channels_get
1612 #define ACCESS_IDX 6
1614 .access = SNDRV_CTL_ELEM_ACCESS_READ,
1615 .iface = SNDRV_CTL_ELEM_IFACE_PCM,
1616 .name = "PCM Slave Access Mode",
1617 .info = loopback_access_info,
1618 .get = loopback_access_get,
1622 static int loopback_mixer_new(struct loopback *loopback, int notify)
1624 struct snd_card *card = loopback->card;
1625 struct snd_pcm *pcm;
1626 struct snd_kcontrol *kctl;
1627 struct loopback_setup *setup;
1628 int err, dev, substr, substr_count, idx;
1630 strcpy(card->mixername, "Loopback Mixer");
1631 for (dev = 0; dev < 2; dev++) {
1632 pcm = loopback->pcm[dev];
1634 pcm->streams[SNDRV_PCM_STREAM_CAPTURE].substream_count;
1635 for (substr = 0; substr < substr_count; substr++) {
1636 setup = &loopback->setup[substr][dev];
1637 setup->notify = notify;
1638 setup->rate_shift = NO_PITCH;
1639 setup->format = SNDRV_PCM_FORMAT_S16_LE;
1640 setup->access = SNDRV_PCM_ACCESS_RW_INTERLEAVED;
1641 setup->rate = 48000;
1642 setup->channels = 2;
1643 for (idx = 0; idx < ARRAY_SIZE(loopback_controls);
1645 kctl = snd_ctl_new1(&loopback_controls[idx],
1649 kctl->id.device = dev;
1650 kctl->id.subdevice = substr;
1652 /* Add the control before copying the id so that
1653 * the numid field of the id is set in the copy.
1655 err = snd_ctl_add(card, kctl);
1661 setup->active_id = kctl->id;
1664 setup->format_id = kctl->id;
1667 setup->rate_id = kctl->id;
1670 setup->channels_id = kctl->id;
1673 setup->access_id = kctl->id;
1684 static void print_dpcm_info(struct snd_info_buffer *buffer,
1685 struct loopback_pcm *dpcm,
1688 snd_iprintf(buffer, " %s\n", id);
1690 snd_iprintf(buffer, " inactive\n");
1693 snd_iprintf(buffer, " buffer_size:\t%u\n", dpcm->pcm_buffer_size);
1694 snd_iprintf(buffer, " buffer_pos:\t\t%u\n", dpcm->buf_pos);
1695 snd_iprintf(buffer, " silent_size:\t%u\n", dpcm->silent_size);
1696 snd_iprintf(buffer, " period_size:\t%u\n", dpcm->pcm_period_size);
1697 snd_iprintf(buffer, " bytes_per_sec:\t%u\n", dpcm->pcm_bps);
1698 snd_iprintf(buffer, " sample_align:\t%u\n", dpcm->pcm_salign);
1699 snd_iprintf(buffer, " rate_shift:\t\t%u\n", dpcm->pcm_rate_shift);
1700 if (dpcm->cable->ops->dpcm_info)
1701 dpcm->cable->ops->dpcm_info(dpcm, buffer);
1704 static void print_substream_info(struct snd_info_buffer *buffer,
1705 struct loopback *loopback,
1709 struct loopback_cable *cable = loopback->cables[sub][num];
1711 snd_iprintf(buffer, "Cable %i substream %i:\n", num, sub);
1712 if (cable == NULL) {
1713 snd_iprintf(buffer, " inactive\n");
1716 snd_iprintf(buffer, " valid: %u\n", cable->valid);
1717 snd_iprintf(buffer, " running: %u\n", cable->running);
1718 snd_iprintf(buffer, " pause: %u\n", cable->pause);
1719 print_dpcm_info(buffer, cable->streams[0], "Playback");
1720 print_dpcm_info(buffer, cable->streams[1], "Capture");
1723 static void print_cable_info(struct snd_info_entry *entry,
1724 struct snd_info_buffer *buffer)
1726 struct loopback *loopback = entry->private_data;
1729 mutex_lock(&loopback->cable_lock);
1730 num = entry->name[strlen(entry->name)-1];
1731 num = num == '0' ? 0 : 1;
1732 for (sub = 0; sub < MAX_PCM_SUBSTREAMS; sub++)
1733 print_substream_info(buffer, loopback, sub, num);
1734 mutex_unlock(&loopback->cable_lock);
1737 static int loopback_cable_proc_new(struct loopback *loopback, int cidx)
1741 snprintf(name, sizeof(name), "cable#%d", cidx);
1742 return snd_card_ro_proc_new(loopback->card, name, loopback,
1746 static void loopback_set_timer_source(struct loopback *loopback,
1749 if (loopback->timer_source) {
1750 devm_kfree(loopback->card->dev, loopback->timer_source);
1751 loopback->timer_source = NULL;
1753 if (value && *value)
1754 loopback->timer_source = devm_kstrdup(loopback->card->dev,
1758 static void print_timer_source_info(struct snd_info_entry *entry,
1759 struct snd_info_buffer *buffer)
1761 struct loopback *loopback = entry->private_data;
1763 mutex_lock(&loopback->cable_lock);
1764 snd_iprintf(buffer, "%s\n",
1765 loopback->timer_source ? loopback->timer_source : "");
1766 mutex_unlock(&loopback->cable_lock);
1769 static void change_timer_source_info(struct snd_info_entry *entry,
1770 struct snd_info_buffer *buffer)
1772 struct loopback *loopback = entry->private_data;
1775 mutex_lock(&loopback->cable_lock);
1776 if (!snd_info_get_line(buffer, line, sizeof(line)))
1777 loopback_set_timer_source(loopback, strim(line));
1778 mutex_unlock(&loopback->cable_lock);
1781 static int loopback_timer_source_proc_new(struct loopback *loopback)
1783 return snd_card_rw_proc_new(loopback->card, "timer_source", loopback,
1784 print_timer_source_info,
1785 change_timer_source_info);
1788 static int loopback_probe(struct platform_device *devptr)
1790 struct snd_card *card;
1791 struct loopback *loopback;
1792 int dev = devptr->id;
1795 err = snd_devm_card_new(&devptr->dev, index[dev], id[dev], THIS_MODULE,
1796 sizeof(struct loopback), &card);
1799 loopback = card->private_data;
1801 if (pcm_substreams[dev] < 1)
1802 pcm_substreams[dev] = 1;
1803 if (pcm_substreams[dev] > MAX_PCM_SUBSTREAMS)
1804 pcm_substreams[dev] = MAX_PCM_SUBSTREAMS;
1806 loopback->card = card;
1807 loopback_set_timer_source(loopback, timer_source[dev]);
1809 mutex_init(&loopback->cable_lock);
1811 err = loopback_pcm_new(loopback, 0, pcm_substreams[dev]);
1814 err = loopback_pcm_new(loopback, 1, pcm_substreams[dev]);
1817 err = loopback_mixer_new(loopback, pcm_notify[dev] ? 1 : 0);
1820 loopback_cable_proc_new(loopback, 0);
1821 loopback_cable_proc_new(loopback, 1);
1822 loopback_timer_source_proc_new(loopback);
1823 strcpy(card->driver, "Loopback");
1824 strcpy(card->shortname, "Loopback");
1825 sprintf(card->longname, "Loopback %i", dev + 1);
1826 err = snd_card_register(card);
1829 platform_set_drvdata(devptr, card);
1833 #ifdef CONFIG_PM_SLEEP
1834 static int loopback_suspend(struct device *pdev)
1836 struct snd_card *card = dev_get_drvdata(pdev);
1838 snd_power_change_state(card, SNDRV_CTL_POWER_D3hot);
1842 static int loopback_resume(struct device *pdev)
1844 struct snd_card *card = dev_get_drvdata(pdev);
1846 snd_power_change_state(card, SNDRV_CTL_POWER_D0);
1850 static SIMPLE_DEV_PM_OPS(loopback_pm, loopback_suspend, loopback_resume);
1851 #define LOOPBACK_PM_OPS &loopback_pm
1853 #define LOOPBACK_PM_OPS NULL
1856 #define SND_LOOPBACK_DRIVER "snd_aloop"
1858 static struct platform_driver loopback_driver = {
1859 .probe = loopback_probe,
1861 .name = SND_LOOPBACK_DRIVER,
1862 .pm = LOOPBACK_PM_OPS,
1866 static void loopback_unregister_all(void)
1870 for (i = 0; i < ARRAY_SIZE(devices); ++i)
1871 platform_device_unregister(devices[i]);
1872 platform_driver_unregister(&loopback_driver);
1875 static int __init alsa_card_loopback_init(void)
1879 err = platform_driver_register(&loopback_driver);
1885 for (i = 0; i < SNDRV_CARDS; i++) {
1886 struct platform_device *device;
1889 device = platform_device_register_simple(SND_LOOPBACK_DRIVER,
1893 if (!platform_get_drvdata(device)) {
1894 platform_device_unregister(device);
1897 devices[i] = device;
1902 printk(KERN_ERR "aloop: No loopback enabled\n");
1904 loopback_unregister_all();
1910 static void __exit alsa_card_loopback_exit(void)
1912 loopback_unregister_all();
1915 module_init(alsa_card_loopback_init)
1916 module_exit(alsa_card_loopback_exit)