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>
32 MODULE_AUTHOR("Jaroslav Kysela <perex@perex.cz>");
33 MODULE_DESCRIPTION("A loopback soundcard");
34 MODULE_LICENSE("GPL");
35 MODULE_SUPPORTED_DEVICE("{{ALSA,Loopback soundcard}}");
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];
45 module_param_array(index, int, NULL, 0444);
46 MODULE_PARM_DESC(index, "Index value for loopback soundcard.");
47 module_param_array(id, charp, NULL, 0444);
48 MODULE_PARM_DESC(id, "ID string for loopback soundcard.");
49 module_param_array(enable, bool, NULL, 0444);
50 MODULE_PARM_DESC(enable, "Enable this loopback soundcard.");
51 module_param_array(pcm_substreams, int, NULL, 0444);
52 MODULE_PARM_DESC(pcm_substreams, "PCM substreams # (1-8) for loopback driver.");
53 module_param_array(pcm_notify, int, NULL, 0444);
54 MODULE_PARM_DESC(pcm_notify, "Break capture when PCM format/rate/channels changes.");
56 #define NO_PITCH 100000
60 struct loopback_cable {
62 struct loopback_pcm *streams[2];
63 struct snd_pcm_hardware hw;
70 struct loopback_setup {
71 unsigned int notify: 1;
72 unsigned int rate_shift;
75 unsigned int channels;
76 struct snd_ctl_elem_id active_id;
77 struct snd_ctl_elem_id format_id;
78 struct snd_ctl_elem_id rate_id;
79 struct snd_ctl_elem_id channels_id;
83 struct snd_card *card;
84 struct mutex cable_lock;
85 struct loopback_cable *cables[MAX_PCM_SUBSTREAMS][2];
86 struct snd_pcm *pcm[2];
87 struct loopback_setup setup[MAX_PCM_SUBSTREAMS][2];
91 struct loopback *loopback;
92 struct snd_pcm_substream *substream;
93 struct loopback_cable *cable;
94 unsigned int pcm_buffer_size;
95 unsigned int buf_pos; /* position in buffer */
96 unsigned int silent_size;
98 unsigned int pcm_period_size;
99 unsigned int pcm_bps; /* bytes per second */
100 unsigned int pcm_salign; /* bytes per sample * channels */
101 unsigned int pcm_rate_shift; /* rate shift value */
103 unsigned int period_update_pending :1;
105 unsigned int irq_pos; /* fractional IRQ position */
106 unsigned int period_size_frac;
107 unsigned int last_drift;
108 unsigned long last_jiffies;
109 struct timer_list timer;
112 static struct platform_device *devices[SNDRV_CARDS];
114 static inline unsigned int byte_pos(struct loopback_pcm *dpcm, unsigned int x)
116 if (dpcm->pcm_rate_shift == NO_PITCH) {
119 x = div_u64(NO_PITCH * (unsigned long long)x,
120 HZ * (unsigned long long)dpcm->pcm_rate_shift);
122 return x - (x % dpcm->pcm_salign);
125 static inline unsigned int frac_pos(struct loopback_pcm *dpcm, unsigned int x)
127 if (dpcm->pcm_rate_shift == NO_PITCH) { /* no pitch */
130 x = div_u64(dpcm->pcm_rate_shift * (unsigned long long)x * HZ,
136 static inline struct loopback_setup *get_setup(struct loopback_pcm *dpcm)
138 int device = dpcm->substream->pstr->pcm->device;
140 if (dpcm->substream->stream == SNDRV_PCM_STREAM_PLAYBACK)
142 return &dpcm->loopback->setup[dpcm->substream->number][device];
145 static inline unsigned int get_notify(struct loopback_pcm *dpcm)
147 return get_setup(dpcm)->notify;
150 static inline unsigned int get_rate_shift(struct loopback_pcm *dpcm)
152 return get_setup(dpcm)->rate_shift;
155 /* call in cable->lock */
156 static void loopback_timer_start(struct loopback_pcm *dpcm)
159 unsigned int rate_shift = get_rate_shift(dpcm);
161 if (rate_shift != dpcm->pcm_rate_shift) {
162 dpcm->pcm_rate_shift = rate_shift;
163 dpcm->period_size_frac = frac_pos(dpcm, dpcm->pcm_period_size);
165 if (dpcm->period_size_frac <= dpcm->irq_pos) {
166 dpcm->irq_pos %= dpcm->period_size_frac;
167 dpcm->period_update_pending = 1;
169 tick = dpcm->period_size_frac - dpcm->irq_pos;
170 tick = (tick + dpcm->pcm_bps - 1) / dpcm->pcm_bps;
171 mod_timer(&dpcm->timer, jiffies + tick);
174 /* call in cable->lock */
175 static inline void loopback_timer_stop(struct loopback_pcm *dpcm)
177 del_timer(&dpcm->timer);
178 dpcm->timer.expires = 0;
181 static inline void loopback_timer_stop_sync(struct loopback_pcm *dpcm)
183 del_timer_sync(&dpcm->timer);
186 #define CABLE_VALID_PLAYBACK (1 << SNDRV_PCM_STREAM_PLAYBACK)
187 #define CABLE_VALID_CAPTURE (1 << SNDRV_PCM_STREAM_CAPTURE)
188 #define CABLE_VALID_BOTH (CABLE_VALID_PLAYBACK|CABLE_VALID_CAPTURE)
190 static int loopback_check_format(struct loopback_cable *cable, int stream)
192 struct snd_pcm_runtime *runtime, *cruntime;
193 struct loopback_setup *setup;
194 struct snd_card *card;
197 if (cable->valid != CABLE_VALID_BOTH) {
198 if (stream == SNDRV_PCM_STREAM_PLAYBACK)
202 runtime = cable->streams[SNDRV_PCM_STREAM_PLAYBACK]->
204 cruntime = cable->streams[SNDRV_PCM_STREAM_CAPTURE]->
206 check = runtime->format != cruntime->format ||
207 runtime->rate != cruntime->rate ||
208 runtime->channels != cruntime->channels;
211 if (stream == SNDRV_PCM_STREAM_CAPTURE) {
214 snd_pcm_stop(cable->streams[SNDRV_PCM_STREAM_CAPTURE]->
215 substream, SNDRV_PCM_STATE_DRAINING);
217 runtime = cable->streams[SNDRV_PCM_STREAM_PLAYBACK]->
219 setup = get_setup(cable->streams[SNDRV_PCM_STREAM_PLAYBACK]);
220 card = cable->streams[SNDRV_PCM_STREAM_PLAYBACK]->loopback->card;
221 if (setup->format != runtime->format) {
222 snd_ctl_notify(card, SNDRV_CTL_EVENT_MASK_VALUE,
224 setup->format = runtime->format;
226 if (setup->rate != runtime->rate) {
227 snd_ctl_notify(card, SNDRV_CTL_EVENT_MASK_VALUE,
229 setup->rate = runtime->rate;
231 if (setup->channels != runtime->channels) {
232 snd_ctl_notify(card, SNDRV_CTL_EVENT_MASK_VALUE,
233 &setup->channels_id);
234 setup->channels = runtime->channels;
240 static void loopback_active_notify(struct loopback_pcm *dpcm)
242 snd_ctl_notify(dpcm->loopback->card,
243 SNDRV_CTL_EVENT_MASK_VALUE,
244 &get_setup(dpcm)->active_id);
247 static int loopback_trigger(struct snd_pcm_substream *substream, int cmd)
249 struct snd_pcm_runtime *runtime = substream->runtime;
250 struct loopback_pcm *dpcm = runtime->private_data;
251 struct loopback_cable *cable = dpcm->cable;
252 int err, stream = 1 << substream->stream;
255 case SNDRV_PCM_TRIGGER_START:
256 err = loopback_check_format(cable, substream->stream);
259 dpcm->last_jiffies = jiffies;
260 dpcm->pcm_rate_shift = 0;
261 dpcm->last_drift = 0;
262 spin_lock(&cable->lock);
263 cable->running |= stream;
264 cable->pause &= ~stream;
265 loopback_timer_start(dpcm);
266 spin_unlock(&cable->lock);
267 if (substream->stream == SNDRV_PCM_STREAM_PLAYBACK)
268 loopback_active_notify(dpcm);
270 case SNDRV_PCM_TRIGGER_STOP:
271 spin_lock(&cable->lock);
272 cable->running &= ~stream;
273 cable->pause &= ~stream;
274 loopback_timer_stop(dpcm);
275 spin_unlock(&cable->lock);
276 if (substream->stream == SNDRV_PCM_STREAM_PLAYBACK)
277 loopback_active_notify(dpcm);
279 case SNDRV_PCM_TRIGGER_PAUSE_PUSH:
280 case SNDRV_PCM_TRIGGER_SUSPEND:
281 spin_lock(&cable->lock);
282 cable->pause |= stream;
283 loopback_timer_stop(dpcm);
284 spin_unlock(&cable->lock);
285 if (substream->stream == SNDRV_PCM_STREAM_PLAYBACK)
286 loopback_active_notify(dpcm);
288 case SNDRV_PCM_TRIGGER_PAUSE_RELEASE:
289 case SNDRV_PCM_TRIGGER_RESUME:
290 spin_lock(&cable->lock);
291 dpcm->last_jiffies = jiffies;
292 cable->pause &= ~stream;
293 loopback_timer_start(dpcm);
294 spin_unlock(&cable->lock);
295 if (substream->stream == SNDRV_PCM_STREAM_PLAYBACK)
296 loopback_active_notify(dpcm);
304 static void params_change(struct snd_pcm_substream *substream)
306 struct snd_pcm_runtime *runtime = substream->runtime;
307 struct loopback_pcm *dpcm = runtime->private_data;
308 struct loopback_cable *cable = dpcm->cable;
310 cable->hw.formats = pcm_format_to_bits(runtime->format);
311 cable->hw.rate_min = runtime->rate;
312 cable->hw.rate_max = runtime->rate;
313 cable->hw.channels_min = runtime->channels;
314 cable->hw.channels_max = runtime->channels;
317 static int loopback_prepare(struct snd_pcm_substream *substream)
319 struct snd_pcm_runtime *runtime = substream->runtime;
320 struct loopback_pcm *dpcm = runtime->private_data;
321 struct loopback_cable *cable = dpcm->cable;
324 loopback_timer_stop_sync(dpcm);
326 salign = (snd_pcm_format_physical_width(runtime->format) *
327 runtime->channels) / 8;
328 bps = salign * runtime->rate;
329 if (bps <= 0 || salign <= 0)
333 dpcm->pcm_buffer_size = frames_to_bytes(runtime, runtime->buffer_size);
334 if (substream->stream == SNDRV_PCM_STREAM_CAPTURE) {
335 /* clear capture buffer */
336 dpcm->silent_size = dpcm->pcm_buffer_size;
337 snd_pcm_format_set_silence(runtime->format, runtime->dma_area,
338 runtime->buffer_size * runtime->channels);
342 dpcm->period_update_pending = 0;
344 dpcm->pcm_salign = salign;
345 dpcm->pcm_period_size = frames_to_bytes(runtime, runtime->period_size);
347 mutex_lock(&dpcm->loopback->cable_lock);
348 if (!(cable->valid & ~(1 << substream->stream)) ||
349 (get_setup(dpcm)->notify &&
350 substream->stream == SNDRV_PCM_STREAM_PLAYBACK))
351 params_change(substream);
352 cable->valid |= 1 << substream->stream;
353 mutex_unlock(&dpcm->loopback->cable_lock);
358 static void clear_capture_buf(struct loopback_pcm *dpcm, unsigned int bytes)
360 struct snd_pcm_runtime *runtime = dpcm->substream->runtime;
361 char *dst = runtime->dma_area;
362 unsigned int dst_off = dpcm->buf_pos;
364 if (dpcm->silent_size >= dpcm->pcm_buffer_size)
366 if (dpcm->silent_size + bytes > dpcm->pcm_buffer_size)
367 bytes = dpcm->pcm_buffer_size - dpcm->silent_size;
370 unsigned int size = bytes;
371 if (dst_off + size > dpcm->pcm_buffer_size)
372 size = dpcm->pcm_buffer_size - dst_off;
373 snd_pcm_format_set_silence(runtime->format, dst + dst_off,
374 bytes_to_frames(runtime, size) *
376 dpcm->silent_size += size;
384 static void copy_play_buf(struct loopback_pcm *play,
385 struct loopback_pcm *capt,
388 struct snd_pcm_runtime *runtime = play->substream->runtime;
389 char *src = runtime->dma_area;
390 char *dst = capt->substream->runtime->dma_area;
391 unsigned int src_off = play->buf_pos;
392 unsigned int dst_off = capt->buf_pos;
393 unsigned int clear_bytes = 0;
395 /* check if playback is draining, trim the capture copy size
396 * when our pointer is at the end of playback ring buffer */
397 if (runtime->status->state == SNDRV_PCM_STATE_DRAINING &&
398 snd_pcm_playback_hw_avail(runtime) < runtime->buffer_size) {
399 snd_pcm_uframes_t appl_ptr, appl_ptr1, diff;
400 appl_ptr = appl_ptr1 = runtime->control->appl_ptr;
401 appl_ptr1 -= appl_ptr1 % runtime->buffer_size;
402 appl_ptr1 += play->buf_pos / play->pcm_salign;
403 if (appl_ptr < appl_ptr1)
404 appl_ptr1 -= runtime->buffer_size;
405 diff = (appl_ptr - appl_ptr1) * play->pcm_salign;
407 clear_bytes = bytes - diff;
413 unsigned int size = bytes;
414 if (src_off + size > play->pcm_buffer_size)
415 size = play->pcm_buffer_size - src_off;
416 if (dst_off + size > capt->pcm_buffer_size)
417 size = capt->pcm_buffer_size - dst_off;
418 memcpy(dst + dst_off, src + src_off, size);
419 capt->silent_size = 0;
423 src_off = (src_off + size) % play->pcm_buffer_size;
424 dst_off = (dst_off + size) % capt->pcm_buffer_size;
427 if (clear_bytes > 0) {
428 clear_capture_buf(capt, clear_bytes);
429 capt->silent_size = 0;
433 static inline unsigned int bytepos_delta(struct loopback_pcm *dpcm,
434 unsigned int jiffies_delta)
436 unsigned long last_pos;
439 last_pos = byte_pos(dpcm, dpcm->irq_pos);
440 dpcm->irq_pos += jiffies_delta * dpcm->pcm_bps;
441 delta = byte_pos(dpcm, dpcm->irq_pos) - last_pos;
442 if (delta >= dpcm->last_drift)
443 delta -= dpcm->last_drift;
444 dpcm->last_drift = 0;
445 if (dpcm->irq_pos >= dpcm->period_size_frac) {
446 dpcm->irq_pos %= dpcm->period_size_frac;
447 dpcm->period_update_pending = 1;
452 static inline void bytepos_finish(struct loopback_pcm *dpcm,
455 dpcm->buf_pos += delta;
456 dpcm->buf_pos %= dpcm->pcm_buffer_size;
459 /* call in cable->lock */
460 static unsigned int loopback_pos_update(struct loopback_cable *cable)
462 struct loopback_pcm *dpcm_play =
463 cable->streams[SNDRV_PCM_STREAM_PLAYBACK];
464 struct loopback_pcm *dpcm_capt =
465 cable->streams[SNDRV_PCM_STREAM_CAPTURE];
466 unsigned long delta_play = 0, delta_capt = 0;
467 unsigned int running, count1, count2;
469 running = cable->running ^ cable->pause;
470 if (running & (1 << SNDRV_PCM_STREAM_PLAYBACK)) {
471 delta_play = jiffies - dpcm_play->last_jiffies;
472 dpcm_play->last_jiffies += delta_play;
475 if (running & (1 << SNDRV_PCM_STREAM_CAPTURE)) {
476 delta_capt = jiffies - dpcm_capt->last_jiffies;
477 dpcm_capt->last_jiffies += delta_capt;
480 if (delta_play == 0 && delta_capt == 0)
483 if (delta_play > delta_capt) {
484 count1 = bytepos_delta(dpcm_play, delta_play - delta_capt);
485 bytepos_finish(dpcm_play, count1);
486 delta_play = delta_capt;
487 } else if (delta_play < delta_capt) {
488 count1 = bytepos_delta(dpcm_capt, delta_capt - delta_play);
489 clear_capture_buf(dpcm_capt, count1);
490 bytepos_finish(dpcm_capt, count1);
491 delta_capt = delta_play;
494 if (delta_play == 0 && delta_capt == 0)
497 /* note delta_capt == delta_play at this moment */
498 count1 = bytepos_delta(dpcm_play, delta_play);
499 count2 = bytepos_delta(dpcm_capt, delta_capt);
500 if (count1 < count2) {
501 dpcm_capt->last_drift = count2 - count1;
503 } else if (count1 > count2) {
504 dpcm_play->last_drift = count1 - count2;
506 copy_play_buf(dpcm_play, dpcm_capt, count1);
507 bytepos_finish(dpcm_play, count1);
508 bytepos_finish(dpcm_capt, count1);
513 static void loopback_timer_function(struct timer_list *t)
515 struct loopback_pcm *dpcm = from_timer(dpcm, t, timer);
518 spin_lock_irqsave(&dpcm->cable->lock, flags);
519 if (loopback_pos_update(dpcm->cable) & (1 << dpcm->substream->stream)) {
520 loopback_timer_start(dpcm);
521 if (dpcm->period_update_pending) {
522 dpcm->period_update_pending = 0;
523 spin_unlock_irqrestore(&dpcm->cable->lock, flags);
524 /* need to unlock before calling below */
525 snd_pcm_period_elapsed(dpcm->substream);
529 spin_unlock_irqrestore(&dpcm->cable->lock, flags);
532 static snd_pcm_uframes_t loopback_pointer(struct snd_pcm_substream *substream)
534 struct snd_pcm_runtime *runtime = substream->runtime;
535 struct loopback_pcm *dpcm = runtime->private_data;
536 snd_pcm_uframes_t pos;
538 spin_lock(&dpcm->cable->lock);
539 loopback_pos_update(dpcm->cable);
541 spin_unlock(&dpcm->cable->lock);
542 return bytes_to_frames(runtime, pos);
545 static const struct snd_pcm_hardware loopback_pcm_hardware =
547 .info = (SNDRV_PCM_INFO_INTERLEAVED | SNDRV_PCM_INFO_MMAP |
548 SNDRV_PCM_INFO_MMAP_VALID | SNDRV_PCM_INFO_PAUSE |
549 SNDRV_PCM_INFO_RESUME),
550 .formats = (SNDRV_PCM_FMTBIT_S16_LE | SNDRV_PCM_FMTBIT_S16_BE |
551 SNDRV_PCM_FMTBIT_S24_LE | SNDRV_PCM_FMTBIT_S24_BE |
552 SNDRV_PCM_FMTBIT_S24_3LE | SNDRV_PCM_FMTBIT_S24_3BE |
553 SNDRV_PCM_FMTBIT_S32_LE | SNDRV_PCM_FMTBIT_S32_BE |
554 SNDRV_PCM_FMTBIT_FLOAT_LE | SNDRV_PCM_FMTBIT_FLOAT_BE),
555 .rates = SNDRV_PCM_RATE_CONTINUOUS | SNDRV_PCM_RATE_8000_192000,
560 .buffer_bytes_max = 2 * 1024 * 1024,
561 .period_bytes_min = 64,
562 /* note check overflow in frac_pos() using pcm_rate_shift before
563 changing period_bytes_max value */
564 .period_bytes_max = 1024 * 1024,
570 static void loopback_runtime_free(struct snd_pcm_runtime *runtime)
572 struct loopback_pcm *dpcm = runtime->private_data;
576 static int loopback_hw_params(struct snd_pcm_substream *substream,
577 struct snd_pcm_hw_params *params)
579 return snd_pcm_lib_alloc_vmalloc_buffer(substream,
580 params_buffer_bytes(params));
583 static int loopback_hw_free(struct snd_pcm_substream *substream)
585 struct snd_pcm_runtime *runtime = substream->runtime;
586 struct loopback_pcm *dpcm = runtime->private_data;
587 struct loopback_cable *cable = dpcm->cable;
589 mutex_lock(&dpcm->loopback->cable_lock);
590 cable->valid &= ~(1 << substream->stream);
591 mutex_unlock(&dpcm->loopback->cable_lock);
592 return snd_pcm_lib_free_vmalloc_buffer(substream);
595 static unsigned int get_cable_index(struct snd_pcm_substream *substream)
597 if (!substream->pcm->device)
598 return substream->stream;
600 return !substream->stream;
603 static int rule_format(struct snd_pcm_hw_params *params,
604 struct snd_pcm_hw_rule *rule)
606 struct loopback_pcm *dpcm = rule->private;
607 struct loopback_cable *cable = dpcm->cable;
611 mutex_lock(&dpcm->loopback->cable_lock);
612 m.bits[0] = (u_int32_t)cable->hw.formats;
613 m.bits[1] = (u_int32_t)(cable->hw.formats >> 32);
614 mutex_unlock(&dpcm->loopback->cable_lock);
615 return snd_mask_refine(hw_param_mask(params, rule->var), &m);
618 static int rule_rate(struct snd_pcm_hw_params *params,
619 struct snd_pcm_hw_rule *rule)
621 struct loopback_pcm *dpcm = rule->private;
622 struct loopback_cable *cable = dpcm->cable;
623 struct snd_interval t;
625 mutex_lock(&dpcm->loopback->cable_lock);
626 t.min = cable->hw.rate_min;
627 t.max = cable->hw.rate_max;
628 mutex_unlock(&dpcm->loopback->cable_lock);
629 t.openmin = t.openmax = 0;
631 return snd_interval_refine(hw_param_interval(params, rule->var), &t);
634 static int rule_channels(struct snd_pcm_hw_params *params,
635 struct snd_pcm_hw_rule *rule)
637 struct loopback_pcm *dpcm = rule->private;
638 struct loopback_cable *cable = dpcm->cable;
639 struct snd_interval t;
641 mutex_lock(&dpcm->loopback->cable_lock);
642 t.min = cable->hw.channels_min;
643 t.max = cable->hw.channels_max;
644 mutex_unlock(&dpcm->loopback->cable_lock);
645 t.openmin = t.openmax = 0;
647 return snd_interval_refine(hw_param_interval(params, rule->var), &t);
650 static void free_cable(struct snd_pcm_substream *substream)
652 struct loopback *loopback = substream->private_data;
653 int dev = get_cable_index(substream);
654 struct loopback_cable *cable;
656 cable = loopback->cables[substream->number][dev];
659 if (cable->streams[!substream->stream]) {
660 /* other stream is still alive */
661 spin_lock_irq(&cable->lock);
662 cable->streams[substream->stream] = NULL;
663 spin_unlock_irq(&cable->lock);
666 loopback->cables[substream->number][dev] = NULL;
671 static int loopback_open(struct snd_pcm_substream *substream)
673 struct snd_pcm_runtime *runtime = substream->runtime;
674 struct loopback *loopback = substream->private_data;
675 struct loopback_pcm *dpcm;
676 struct loopback_cable *cable = NULL;
678 int dev = get_cable_index(substream);
680 mutex_lock(&loopback->cable_lock);
681 dpcm = kzalloc(sizeof(*dpcm), GFP_KERNEL);
686 dpcm->loopback = loopback;
687 dpcm->substream = substream;
688 timer_setup(&dpcm->timer, loopback_timer_function, 0);
690 cable = loopback->cables[substream->number][dev];
692 cable = kzalloc(sizeof(*cable), GFP_KERNEL);
697 spin_lock_init(&cable->lock);
698 cable->hw = loopback_pcm_hardware;
699 loopback->cables[substream->number][dev] = cable;
703 snd_pcm_hw_constraint_integer(runtime, SNDRV_PCM_HW_PARAM_PERIODS);
705 /* use dynamic rules based on actual runtime->hw values */
706 /* note that the default rules created in the PCM midlevel code */
707 /* are cached -> they do not reflect the actual state */
708 err = snd_pcm_hw_rule_add(runtime, 0,
709 SNDRV_PCM_HW_PARAM_FORMAT,
711 SNDRV_PCM_HW_PARAM_FORMAT, -1);
714 err = snd_pcm_hw_rule_add(runtime, 0,
715 SNDRV_PCM_HW_PARAM_RATE,
717 SNDRV_PCM_HW_PARAM_RATE, -1);
720 err = snd_pcm_hw_rule_add(runtime, 0,
721 SNDRV_PCM_HW_PARAM_CHANNELS,
723 SNDRV_PCM_HW_PARAM_CHANNELS, -1);
727 runtime->private_data = dpcm;
728 runtime->private_free = loopback_runtime_free;
729 if (get_notify(dpcm))
730 runtime->hw = loopback_pcm_hardware;
732 runtime->hw = cable->hw;
734 spin_lock_irq(&cable->lock);
735 cable->streams[substream->stream] = dpcm;
736 spin_unlock_irq(&cable->lock);
740 free_cable(substream);
743 mutex_unlock(&loopback->cable_lock);
747 static int loopback_close(struct snd_pcm_substream *substream)
749 struct loopback *loopback = substream->private_data;
750 struct loopback_pcm *dpcm = substream->runtime->private_data;
752 loopback_timer_stop_sync(dpcm);
753 mutex_lock(&loopback->cable_lock);
754 free_cable(substream);
755 mutex_unlock(&loopback->cable_lock);
759 static const struct snd_pcm_ops loopback_pcm_ops = {
760 .open = loopback_open,
761 .close = loopback_close,
762 .ioctl = snd_pcm_lib_ioctl,
763 .hw_params = loopback_hw_params,
764 .hw_free = loopback_hw_free,
765 .prepare = loopback_prepare,
766 .trigger = loopback_trigger,
767 .pointer = loopback_pointer,
768 .page = snd_pcm_lib_get_vmalloc_page,
771 static int loopback_pcm_new(struct loopback *loopback,
772 int device, int substreams)
777 err = snd_pcm_new(loopback->card, "Loopback PCM", device,
778 substreams, substreams, &pcm);
781 snd_pcm_set_ops(pcm, SNDRV_PCM_STREAM_PLAYBACK, &loopback_pcm_ops);
782 snd_pcm_set_ops(pcm, SNDRV_PCM_STREAM_CAPTURE, &loopback_pcm_ops);
784 pcm->private_data = loopback;
786 strcpy(pcm->name, "Loopback PCM");
788 loopback->pcm[device] = pcm;
792 static int loopback_rate_shift_info(struct snd_kcontrol *kcontrol,
793 struct snd_ctl_elem_info *uinfo)
795 uinfo->type = SNDRV_CTL_ELEM_TYPE_INTEGER;
797 uinfo->value.integer.min = 80000;
798 uinfo->value.integer.max = 120000;
799 uinfo->value.integer.step = 1;
803 static int loopback_rate_shift_get(struct snd_kcontrol *kcontrol,
804 struct snd_ctl_elem_value *ucontrol)
806 struct loopback *loopback = snd_kcontrol_chip(kcontrol);
808 mutex_lock(&loopback->cable_lock);
809 ucontrol->value.integer.value[0] =
810 loopback->setup[kcontrol->id.subdevice]
811 [kcontrol->id.device].rate_shift;
812 mutex_unlock(&loopback->cable_lock);
816 static int loopback_rate_shift_put(struct snd_kcontrol *kcontrol,
817 struct snd_ctl_elem_value *ucontrol)
819 struct loopback *loopback = snd_kcontrol_chip(kcontrol);
823 val = ucontrol->value.integer.value[0];
828 mutex_lock(&loopback->cable_lock);
829 if (val != loopback->setup[kcontrol->id.subdevice]
830 [kcontrol->id.device].rate_shift) {
831 loopback->setup[kcontrol->id.subdevice]
832 [kcontrol->id.device].rate_shift = val;
835 mutex_unlock(&loopback->cable_lock);
839 static int loopback_notify_get(struct snd_kcontrol *kcontrol,
840 struct snd_ctl_elem_value *ucontrol)
842 struct loopback *loopback = snd_kcontrol_chip(kcontrol);
844 mutex_lock(&loopback->cable_lock);
845 ucontrol->value.integer.value[0] =
846 loopback->setup[kcontrol->id.subdevice]
847 [kcontrol->id.device].notify;
848 mutex_unlock(&loopback->cable_lock);
852 static int loopback_notify_put(struct snd_kcontrol *kcontrol,
853 struct snd_ctl_elem_value *ucontrol)
855 struct loopback *loopback = snd_kcontrol_chip(kcontrol);
859 val = ucontrol->value.integer.value[0] ? 1 : 0;
860 mutex_lock(&loopback->cable_lock);
861 if (val != loopback->setup[kcontrol->id.subdevice]
862 [kcontrol->id.device].notify) {
863 loopback->setup[kcontrol->id.subdevice]
864 [kcontrol->id.device].notify = val;
867 mutex_unlock(&loopback->cable_lock);
871 static int loopback_active_get(struct snd_kcontrol *kcontrol,
872 struct snd_ctl_elem_value *ucontrol)
874 struct loopback *loopback = snd_kcontrol_chip(kcontrol);
875 struct loopback_cable *cable;
877 unsigned int val = 0;
879 mutex_lock(&loopback->cable_lock);
880 cable = loopback->cables[kcontrol->id.subdevice][kcontrol->id.device ^ 1];
882 unsigned int running = cable->running ^ cable->pause;
884 val = (running & (1 << SNDRV_PCM_STREAM_PLAYBACK)) ? 1 : 0;
886 mutex_unlock(&loopback->cable_lock);
887 ucontrol->value.integer.value[0] = val;
891 static int loopback_format_info(struct snd_kcontrol *kcontrol,
892 struct snd_ctl_elem_info *uinfo)
894 uinfo->type = SNDRV_CTL_ELEM_TYPE_INTEGER;
896 uinfo->value.integer.min = 0;
897 uinfo->value.integer.max = SNDRV_PCM_FORMAT_LAST;
898 uinfo->value.integer.step = 1;
902 static int loopback_format_get(struct snd_kcontrol *kcontrol,
903 struct snd_ctl_elem_value *ucontrol)
905 struct loopback *loopback = snd_kcontrol_chip(kcontrol);
907 ucontrol->value.integer.value[0] =
908 loopback->setup[kcontrol->id.subdevice]
909 [kcontrol->id.device].format;
913 static int loopback_rate_info(struct snd_kcontrol *kcontrol,
914 struct snd_ctl_elem_info *uinfo)
916 uinfo->type = SNDRV_CTL_ELEM_TYPE_INTEGER;
918 uinfo->value.integer.min = 0;
919 uinfo->value.integer.max = 192000;
920 uinfo->value.integer.step = 1;
924 static int loopback_rate_get(struct snd_kcontrol *kcontrol,
925 struct snd_ctl_elem_value *ucontrol)
927 struct loopback *loopback = snd_kcontrol_chip(kcontrol);
929 mutex_lock(&loopback->cable_lock);
930 ucontrol->value.integer.value[0] =
931 loopback->setup[kcontrol->id.subdevice]
932 [kcontrol->id.device].rate;
933 mutex_unlock(&loopback->cable_lock);
937 static int loopback_channels_info(struct snd_kcontrol *kcontrol,
938 struct snd_ctl_elem_info *uinfo)
940 uinfo->type = SNDRV_CTL_ELEM_TYPE_INTEGER;
942 uinfo->value.integer.min = 1;
943 uinfo->value.integer.max = 1024;
944 uinfo->value.integer.step = 1;
948 static int loopback_channels_get(struct snd_kcontrol *kcontrol,
949 struct snd_ctl_elem_value *ucontrol)
951 struct loopback *loopback = snd_kcontrol_chip(kcontrol);
953 mutex_lock(&loopback->cable_lock);
954 ucontrol->value.integer.value[0] =
955 loopback->setup[kcontrol->id.subdevice]
956 [kcontrol->id.device].channels;
957 mutex_unlock(&loopback->cable_lock);
961 static struct snd_kcontrol_new loopback_controls[] = {
963 .iface = SNDRV_CTL_ELEM_IFACE_PCM,
964 .name = "PCM Rate Shift 100000",
965 .info = loopback_rate_shift_info,
966 .get = loopback_rate_shift_get,
967 .put = loopback_rate_shift_put,
970 .iface = SNDRV_CTL_ELEM_IFACE_PCM,
971 .name = "PCM Notify",
972 .info = snd_ctl_boolean_mono_info,
973 .get = loopback_notify_get,
974 .put = loopback_notify_put,
978 .access = SNDRV_CTL_ELEM_ACCESS_READ,
979 .iface = SNDRV_CTL_ELEM_IFACE_PCM,
980 .name = "PCM Slave Active",
981 .info = snd_ctl_boolean_mono_info,
982 .get = loopback_active_get,
986 .access = SNDRV_CTL_ELEM_ACCESS_READ,
987 .iface = SNDRV_CTL_ELEM_IFACE_PCM,
988 .name = "PCM Slave Format",
989 .info = loopback_format_info,
990 .get = loopback_format_get
994 .access = SNDRV_CTL_ELEM_ACCESS_READ,
995 .iface = SNDRV_CTL_ELEM_IFACE_PCM,
996 .name = "PCM Slave Rate",
997 .info = loopback_rate_info,
998 .get = loopback_rate_get
1000 #define CHANNELS_IDX 5
1002 .access = SNDRV_CTL_ELEM_ACCESS_READ,
1003 .iface = SNDRV_CTL_ELEM_IFACE_PCM,
1004 .name = "PCM Slave Channels",
1005 .info = loopback_channels_info,
1006 .get = loopback_channels_get
1010 static int loopback_mixer_new(struct loopback *loopback, int notify)
1012 struct snd_card *card = loopback->card;
1013 struct snd_pcm *pcm;
1014 struct snd_kcontrol *kctl;
1015 struct loopback_setup *setup;
1016 int err, dev, substr, substr_count, idx;
1018 strcpy(card->mixername, "Loopback Mixer");
1019 for (dev = 0; dev < 2; dev++) {
1020 pcm = loopback->pcm[dev];
1022 pcm->streams[SNDRV_PCM_STREAM_CAPTURE].substream_count;
1023 for (substr = 0; substr < substr_count; substr++) {
1024 setup = &loopback->setup[substr][dev];
1025 setup->notify = notify;
1026 setup->rate_shift = NO_PITCH;
1027 setup->format = SNDRV_PCM_FORMAT_S16_LE;
1028 setup->rate = 48000;
1029 setup->channels = 2;
1030 for (idx = 0; idx < ARRAY_SIZE(loopback_controls);
1032 kctl = snd_ctl_new1(&loopback_controls[idx],
1036 kctl->id.device = dev;
1037 kctl->id.subdevice = substr;
1040 setup->active_id = kctl->id;
1043 setup->format_id = kctl->id;
1046 setup->rate_id = kctl->id;
1049 setup->channels_id = kctl->id;
1054 err = snd_ctl_add(card, kctl);
1063 static void print_dpcm_info(struct snd_info_buffer *buffer,
1064 struct loopback_pcm *dpcm,
1067 snd_iprintf(buffer, " %s\n", id);
1069 snd_iprintf(buffer, " inactive\n");
1072 snd_iprintf(buffer, " buffer_size:\t%u\n", dpcm->pcm_buffer_size);
1073 snd_iprintf(buffer, " buffer_pos:\t\t%u\n", dpcm->buf_pos);
1074 snd_iprintf(buffer, " silent_size:\t%u\n", dpcm->silent_size);
1075 snd_iprintf(buffer, " period_size:\t%u\n", dpcm->pcm_period_size);
1076 snd_iprintf(buffer, " bytes_per_sec:\t%u\n", dpcm->pcm_bps);
1077 snd_iprintf(buffer, " sample_align:\t%u\n", dpcm->pcm_salign);
1078 snd_iprintf(buffer, " rate_shift:\t\t%u\n", dpcm->pcm_rate_shift);
1079 snd_iprintf(buffer, " update_pending:\t%u\n",
1080 dpcm->period_update_pending);
1081 snd_iprintf(buffer, " irq_pos:\t\t%u\n", dpcm->irq_pos);
1082 snd_iprintf(buffer, " period_frac:\t%u\n", dpcm->period_size_frac);
1083 snd_iprintf(buffer, " last_jiffies:\t%lu (%lu)\n",
1084 dpcm->last_jiffies, jiffies);
1085 snd_iprintf(buffer, " timer_expires:\t%lu\n", dpcm->timer.expires);
1088 static void print_substream_info(struct snd_info_buffer *buffer,
1089 struct loopback *loopback,
1093 struct loopback_cable *cable = loopback->cables[sub][num];
1095 snd_iprintf(buffer, "Cable %i substream %i:\n", num, sub);
1096 if (cable == NULL) {
1097 snd_iprintf(buffer, " inactive\n");
1100 snd_iprintf(buffer, " valid: %u\n", cable->valid);
1101 snd_iprintf(buffer, " running: %u\n", cable->running);
1102 snd_iprintf(buffer, " pause: %u\n", cable->pause);
1103 print_dpcm_info(buffer, cable->streams[0], "Playback");
1104 print_dpcm_info(buffer, cable->streams[1], "Capture");
1107 static void print_cable_info(struct snd_info_entry *entry,
1108 struct snd_info_buffer *buffer)
1110 struct loopback *loopback = entry->private_data;
1113 mutex_lock(&loopback->cable_lock);
1114 num = entry->name[strlen(entry->name)-1];
1115 num = num == '0' ? 0 : 1;
1116 for (sub = 0; sub < MAX_PCM_SUBSTREAMS; sub++)
1117 print_substream_info(buffer, loopback, sub, num);
1118 mutex_unlock(&loopback->cable_lock);
1121 static int loopback_proc_new(struct loopback *loopback, int cidx)
1125 snprintf(name, sizeof(name), "cable#%d", cidx);
1126 return snd_card_ro_proc_new(loopback->card, name, loopback,
1130 static int loopback_probe(struct platform_device *devptr)
1132 struct snd_card *card;
1133 struct loopback *loopback;
1134 int dev = devptr->id;
1137 err = snd_card_new(&devptr->dev, index[dev], id[dev], THIS_MODULE,
1138 sizeof(struct loopback), &card);
1141 loopback = card->private_data;
1143 if (pcm_substreams[dev] < 1)
1144 pcm_substreams[dev] = 1;
1145 if (pcm_substreams[dev] > MAX_PCM_SUBSTREAMS)
1146 pcm_substreams[dev] = MAX_PCM_SUBSTREAMS;
1148 loopback->card = card;
1149 mutex_init(&loopback->cable_lock);
1151 err = loopback_pcm_new(loopback, 0, pcm_substreams[dev]);
1154 err = loopback_pcm_new(loopback, 1, pcm_substreams[dev]);
1157 err = loopback_mixer_new(loopback, pcm_notify[dev] ? 1 : 0);
1160 loopback_proc_new(loopback, 0);
1161 loopback_proc_new(loopback, 1);
1162 strcpy(card->driver, "Loopback");
1163 strcpy(card->shortname, "Loopback");
1164 sprintf(card->longname, "Loopback %i", dev + 1);
1165 err = snd_card_register(card);
1167 platform_set_drvdata(devptr, card);
1171 snd_card_free(card);
1175 static int loopback_remove(struct platform_device *devptr)
1177 snd_card_free(platform_get_drvdata(devptr));
1181 #ifdef CONFIG_PM_SLEEP
1182 static int loopback_suspend(struct device *pdev)
1184 struct snd_card *card = dev_get_drvdata(pdev);
1186 snd_power_change_state(card, SNDRV_CTL_POWER_D3hot);
1190 static int loopback_resume(struct device *pdev)
1192 struct snd_card *card = dev_get_drvdata(pdev);
1194 snd_power_change_state(card, SNDRV_CTL_POWER_D0);
1198 static SIMPLE_DEV_PM_OPS(loopback_pm, loopback_suspend, loopback_resume);
1199 #define LOOPBACK_PM_OPS &loopback_pm
1201 #define LOOPBACK_PM_OPS NULL
1204 #define SND_LOOPBACK_DRIVER "snd_aloop"
1206 static struct platform_driver loopback_driver = {
1207 .probe = loopback_probe,
1208 .remove = loopback_remove,
1210 .name = SND_LOOPBACK_DRIVER,
1211 .pm = LOOPBACK_PM_OPS,
1215 static void loopback_unregister_all(void)
1219 for (i = 0; i < ARRAY_SIZE(devices); ++i)
1220 platform_device_unregister(devices[i]);
1221 platform_driver_unregister(&loopback_driver);
1224 static int __init alsa_card_loopback_init(void)
1228 err = platform_driver_register(&loopback_driver);
1234 for (i = 0; i < SNDRV_CARDS; i++) {
1235 struct platform_device *device;
1238 device = platform_device_register_simple(SND_LOOPBACK_DRIVER,
1242 if (!platform_get_drvdata(device)) {
1243 platform_device_unregister(device);
1246 devices[i] = device;
1251 printk(KERN_ERR "aloop: No loopback enabled\n");
1253 loopback_unregister_all();
1259 static void __exit alsa_card_loopback_exit(void)
1261 loopback_unregister_all();
1264 module_init(alsa_card_loopback_init)
1265 module_exit(alsa_card_loopback_exit)