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 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;
129 };
130
131 struct loopback {
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;
138 };
139
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;
147 /* PCM parameters */
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 */
152 /* flags */
153 unsigned int period_update_pending :1;
154 /* timer stuff */
155 unsigned int irq_pos; /* fractional IRQ position in jiffies
156 * ticks
157 */
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;
163
164 /* size of per channel buffer in case of non-interleaved access */
165 unsigned int channel_buf_n;
166 };
167
168 static struct platform_device *devices[SNDRV_CARDS];
169
170 static inline unsigned int byte_pos(struct loopback_pcm *dpcm, unsigned int x)
171 {
172 if (dpcm->pcm_rate_shift == NO_PITCH) {
173 x /= HZ;
174 } else {
175 x = div_u64(NO_PITCH * (unsigned long long)x,
176 HZ * (unsigned long long)dpcm->pcm_rate_shift);
177 }
178 return x - (x % dpcm->pcm_salign);
179 }
180
181 static inline unsigned int frac_pos(struct loopback_pcm *dpcm, unsigned int x)
182 {
183 if (dpcm->pcm_rate_shift == NO_PITCH) { /* no pitch */
184 return x * HZ;
185 } else {
186 x = div_u64(dpcm->pcm_rate_shift * (unsigned long long)x * HZ,
187 NO_PITCH);
188 }
189 return x;
190 }
191
192 static inline struct loopback_setup *get_setup(struct loopback_pcm *dpcm)
193 {
194 int device = dpcm->substream->pstr->pcm->device;
195
196 if (dpcm->substream->stream == SNDRV_PCM_STREAM_PLAYBACK)
197 device ^= 1;
198 return &dpcm->loopback->setup[dpcm->substream->number][device];
199 }
200
201 static inline unsigned int get_notify(struct loopback_pcm *dpcm)
202 {
203 return get_setup(dpcm)->notify;
204 }
205
206 static inline unsigned int get_rate_shift(struct loopback_pcm *dpcm)
207 {
208 return get_setup(dpcm)->rate_shift;
209 }
210
211 /* call in cable->lock */
212 static int loopback_jiffies_timer_start(struct loopback_pcm *dpcm)
213 {
214 unsigned long tick;
215 unsigned int rate_shift = get_rate_shift(dpcm);
216
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);
220 }
221 if (dpcm->period_size_frac <= dpcm->irq_pos) {
222 dpcm->irq_pos %= dpcm->period_size_frac;
223 dpcm->period_update_pending = 1;
224 }
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);
228
229 return 0;
230 }
231
232 /* call in cable->lock */
233 static int loopback_snd_timer_start(struct loopback_pcm *dpcm)
234 {
235 struct loopback_cable *cable = dpcm->cable;
236 int err;
237
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.
240 */
241 err = snd_timer_start(cable->snd_timer.instance, 1);
242 if (err < 0) {
243 /* do not report error if trying to start but already
244 * running. For example called by opposite substream
245 * of the same cable
246 */
247 if (err == -EBUSY)
248 return 0;
249
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,
255 err);
256 }
257
258 return err;
259 }
260
261 /* call in cable->lock */
262 static inline int loopback_jiffies_timer_stop(struct loopback_pcm *dpcm)
263 {
264 del_timer(&dpcm->timer);
265 dpcm->timer.expires = 0;
266
267 return 0;
268 }
269
270 /* call in cable->lock */
271 static int loopback_snd_timer_stop(struct loopback_pcm *dpcm)
272 {
273 struct loopback_cable *cable = dpcm->cable;
274 int err;
275
276 /* only stop if both devices (playback and capture) are not running */
277 if (cable->running ^ cable->pause)
278 return 0;
279
280 err = snd_timer_stop(cable->snd_timer.instance);
281 if (err < 0) {
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,
287 err);
288 }
289
290 return err;
291 }
292
293 static inline int loopback_jiffies_timer_stop_sync(struct loopback_pcm *dpcm)
294 {
295 del_timer_sync(&dpcm->timer);
296
297 return 0;
298 }
299
300 /* call in loopback->cable_lock */
301 static int loopback_snd_timer_close_cable(struct loopback_pcm *dpcm)
302 {
303 struct loopback_cable *cable = dpcm->cable;
304
305 /* snd_timer was not opened */
306 if (!cable->snd_timer.instance)
307 return 0;
308
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
312 * cable->lock;
313 */
314 snd_timer_close(cable->snd_timer.instance);
315
316 /* wait till drain work has finished if requested */
317 cancel_work_sync(&cable->snd_timer.event_work);
318
319 snd_timer_instance_free(cable->snd_timer.instance);
320 memset(&cable->snd_timer, 0, sizeof(cable->snd_timer));
321
322 return 0;
323 }
324
325 static bool is_access_interleaved(snd_pcm_access_t access)
326 {
327 switch (access) {
328 case SNDRV_PCM_ACCESS_MMAP_INTERLEAVED:
329 case SNDRV_PCM_ACCESS_RW_INTERLEAVED:
330 return true;
331 default:
332 return false;
333 }
334 };
335
336 static int loopback_check_format(struct loopback_cable *cable, int stream)
337 {
338 struct snd_pcm_runtime *runtime, *cruntime;
339 struct loopback_setup *setup;
340 struct snd_card *card;
341 int check;
342
343 if (cable->valid != CABLE_VALID_BOTH) {
344 if (stream == SNDRV_PCM_STREAM_PLAYBACK)
345 goto __notify;
346 return 0;
347 }
348 runtime = cable->streams[SNDRV_PCM_STREAM_PLAYBACK]->
349 substream->runtime;
350 cruntime = cable->streams[SNDRV_PCM_STREAM_CAPTURE]->
351 substream->runtime;
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);
357 if (!check)
358 return 0;
359 if (stream == SNDRV_PCM_STREAM_CAPTURE) {
360 return -EIO;
361 } else {
362 snd_pcm_stop(cable->streams[SNDRV_PCM_STREAM_CAPTURE]->
363 substream, SNDRV_PCM_STATE_DRAINING);
364 __notify:
365 runtime = cable->streams[SNDRV_PCM_STREAM_PLAYBACK]->
366 substream->runtime;
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,
371 &setup->format_id);
372 setup->format = runtime->format;
373 }
374 if (setup->rate != runtime->rate) {
375 snd_ctl_notify(card, SNDRV_CTL_EVENT_MASK_VALUE,
376 &setup->rate_id);
377 setup->rate = runtime->rate;
378 }
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;
383 }
384 if (is_access_interleaved(setup->access) !=
385 is_access_interleaved(runtime->access)) {
386 snd_ctl_notify(card, SNDRV_CTL_EVENT_MASK_VALUE,
387 &setup->access_id);
388 setup->access = runtime->access;
389 }
390 }
391 return 0;
392 }
393
394 static void loopback_active_notify(struct loopback_pcm *dpcm)
395 {
396 snd_ctl_notify(dpcm->loopback->card,
397 SNDRV_CTL_EVENT_MASK_VALUE,
398 &get_setup(dpcm)->active_id);
399 }
400
401 static int loopback_trigger(struct snd_pcm_substream *substream, int cmd)
402 {
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;
407
408 switch (cmd) {
409 case SNDRV_PCM_TRIGGER_START:
410 err = loopback_check_format(cable, substream->stream);
411 if (err < 0)
412 return err;
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);
423 break;
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);
432 break;
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);
441 break;
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);
451 break;
452 default:
453 return -EINVAL;
454 }
455 return err;
456 }
457
458 static void params_change(struct snd_pcm_substream *substream)
459 {
460 struct snd_pcm_runtime *runtime = substream->runtime;
461 struct loopback_pcm *dpcm = runtime->private_data;
462 struct loopback_cable *cable = dpcm->cable;
463
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;
469
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;
474 }
475
476 }
477
478 static int loopback_prepare(struct snd_pcm_substream *substream)
479 {
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;
484
485 if (cable->ops->stop_sync) {
486 err = cable->ops->stop_sync(dpcm);
487 if (err < 0)
488 return err;
489 }
490
491 salign = (snd_pcm_format_physical_width(runtime->format) *
492 runtime->channels) / 8;
493 bps = salign * runtime->rate;
494 if (bps <= 0 || salign <= 0)
495 return -EINVAL;
496
497 dpcm->buf_pos = 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);
505 }
506
507 dpcm->irq_pos = 0;
508 dpcm->period_update_pending = 0;
509 dpcm->pcm_bps = bps;
510 dpcm->pcm_salign = salign;
511 dpcm->pcm_period_size = frames_to_bytes(runtime, runtime->period_size);
512
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);
520
521 return 0;
522 }
523
524 static void clear_capture_buf(struct loopback_pcm *dpcm, unsigned int bytes)
525 {
526 struct snd_pcm_runtime *runtime = dpcm->substream->runtime;
527 char *dst = runtime->dma_area;
528 unsigned int dst_off = dpcm->buf_pos;
529
530 if (dpcm->silent_size >= dpcm->pcm_buffer_size)
531 return;
532 if (dpcm->silent_size + bytes > dpcm->pcm_buffer_size)
533 bytes = dpcm->pcm_buffer_size - dpcm->silent_size;
534
535 for (;;) {
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) *
541 runtime->channels);
542 dpcm->silent_size += size;
543 bytes -= size;
544 if (!bytes)
545 break;
546 dst_off = 0;
547 }
548 }
549
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)
552 {
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;
557 int i;
558
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,
562 size_p_ch);
563 }
564 }
565
566 static void copy_play_buf(struct loopback_pcm *play,
567 struct loopback_pcm *capt,
568 unsigned int bytes)
569 {
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;
576
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;
588 if (diff < bytes) {
589 clear_bytes = bytes - diff;
590 bytes = diff;
591 }
592 }
593
594 for (;;) {
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);
602 else
603 memcpy(dst + dst_off, src + src_off, size);
604 capt->silent_size = 0;
605 bytes -= size;
606 if (!bytes)
607 break;
608 src_off = (src_off + size) % play->pcm_buffer_size;
609 dst_off = (dst_off + size) % capt->pcm_buffer_size;
610 }
611
612 if (clear_bytes > 0) {
613 clear_capture_buf(capt, clear_bytes);
614 capt->silent_size = 0;
615 }
616 }
617
618 static inline unsigned int bytepos_delta(struct loopback_pcm *dpcm,
619 unsigned int jiffies_delta)
620 {
621 unsigned long last_pos;
622 unsigned int delta;
623
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;
633 }
634 return delta;
635 }
636
637 static inline void bytepos_finish(struct loopback_pcm *dpcm,
638 unsigned int delta)
639 {
640 dpcm->buf_pos += delta;
641 dpcm->buf_pos %= dpcm->pcm_buffer_size;
642 }
643
644 /* call in cable->lock */
645 static unsigned int loopback_jiffies_timer_pos_update
646 (struct loopback_cable *cable)
647 {
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;
654
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;
660 }
661
662 if (running & (1 << SNDRV_PCM_STREAM_CAPTURE)) {
663 delta_capt = cur_jiffies - dpcm_capt->last_jiffies;
664 dpcm_capt->last_jiffies += delta_capt;
665 }
666
667 if (delta_play == 0 && delta_capt == 0)
668 goto unlock;
669
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;
679 }
680
681 if (delta_play == 0 && delta_capt == 0)
682 goto unlock;
683
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;
689 count1 = count2;
690 } else if (count1 > count2) {
691 dpcm_play->last_drift = count1 - count2;
692 }
693 copy_play_buf(dpcm_play, dpcm_capt, count1);
694 bytepos_finish(dpcm_play, count1);
695 bytepos_finish(dpcm_capt, count1);
696 unlock:
697 return running;
698 }
699
700 static void loopback_jiffies_timer_function(struct timer_list *t)
701 {
702 struct loopback_pcm *dpcm = from_timer(dpcm, t, timer);
703 unsigned long flags;
704
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);
714 return;
715 }
716 }
717 spin_unlock_irqrestore(&dpcm->cable->lock, flags);
718 }
719
720 /* call in cable->lock */
721 static int loopback_snd_timer_check_resolution(struct snd_pcm_runtime *runtime,
722 unsigned long resolution)
723 {
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
730 *
731 * period_size <= 65.536.000.000 nsec / 1000nsec/usec * 192kHz +
732 * 500.000
733 * period_size <= 12.582.912.000.000 <64bit
734 * / 1.000.000 usec/sec
735 */
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);
741
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,
748 period_size);
749 return -EINVAL;
750 }
751 return 0;
752 }
753
754 static void loopback_snd_timer_period_elapsed(struct loopback_cable *cable,
755 int event,
756 unsigned long resolution)
757 {
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;
762 unsigned long flags;
763
764 spin_lock_irqsave(&cable->lock, flags);
765 running = cable->running ^ cable->pause;
766 /* no need to do anything if no stream is running */
767 if (!running) {
768 spin_unlock_irqrestore(&cable->lock, flags);
769 return;
770 }
771
772 dpcm_play = cable->streams[SNDRV_PCM_STREAM_PLAYBACK];
773 dpcm_capt = cable->streams[SNDRV_PCM_STREAM_CAPTURE];
774
775 if (event == SNDRV_TIMER_EVENT_MSTOP) {
776 if (!dpcm_play ||
777 dpcm_play->substream->runtime->state !=
778 SNDRV_PCM_STATE_DRAINING) {
779 spin_unlock_irqrestore(&cable->lock, flags);
780 return;
781 }
782 }
783
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;
791
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
796 * here.
797 */
798 if (loopback_snd_timer_check_resolution(valid_runtime,
799 resolution) < 0) {
800 spin_unlock_irqrestore(&cable->lock, flags);
801 if (substream_play)
802 snd_pcm_stop_xrun(substream_play);
803 if (substream_capt)
804 snd_pcm_stop_xrun(substream_capt);
805 return;
806 }
807 }
808
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);
822 }
823 spin_unlock_irqrestore(&cable->lock, flags);
824
825 if (substream_play)
826 snd_pcm_period_elapsed(substream_play);
827 if (substream_capt)
828 snd_pcm_period_elapsed(substream_capt);
829 }
830
831 static void loopback_snd_timer_function(struct snd_timer_instance *timeri,
832 unsigned long resolution,
833 unsigned long ticks)
834 {
835 struct loopback_cable *cable = timeri->callback_data;
836
837 loopback_snd_timer_period_elapsed(cable, SNDRV_TIMER_EVENT_TICK,
838 resolution);
839 }
840
841 static void loopback_snd_timer_work(struct work_struct *work)
842 {
843 struct loopback_cable *cable;
844
845 cable = container_of(work, struct loopback_cable, snd_timer.event_work);
846 loopback_snd_timer_period_elapsed(cable, SNDRV_TIMER_EVENT_MSTOP, 0);
847 }
848
849 static void loopback_snd_timer_event(struct snd_timer_instance *timeri,
850 int event,
851 struct timespec64 *tstamp,
852 unsigned long resolution)
853 {
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
856 * timer->lock e.g.
857 * loopback_trigger()
858 * spin_lock(&cable->lock)
859 * loopback_snd_timer_start()
860 * snd_timer_start()
861 * spin_lock(&timer->lock)
862 * Therefore when using the oposit order of locks here it could result
863 * in a deadlock.
864 */
865
866 if (event == SNDRV_TIMER_EVENT_MSTOP) {
867 struct loopback_cable *cable = timeri->callback_data;
868
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()
876 */
877 schedule_work(&cable->snd_timer.event_work);
878 }
879 }
880
881 static void loopback_jiffies_timer_dpcm_info(struct loopback_pcm *dpcm,
882 struct snd_info_buffer *buffer)
883 {
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);
891 }
892
893 static void loopback_snd_timer_dpcm_info(struct loopback_pcm *dpcm,
894 struct snd_info_buffer *buffer)
895 {
896 struct loopback_cable *cable = dpcm->cable;
897
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");
905 }
906
907 static snd_pcm_uframes_t loopback_pointer(struct snd_pcm_substream *substream)
908 {
909 struct snd_pcm_runtime *runtime = substream->runtime;
910 struct loopback_pcm *dpcm = runtime->private_data;
911 snd_pcm_uframes_t pos;
912
913 spin_lock(&dpcm->cable->lock);
914 if (dpcm->cable->ops->pos_update)
915 dpcm->cable->ops->pos_update(dpcm->cable);
916 pos = dpcm->buf_pos;
917 spin_unlock(&dpcm->cable->lock);
918 return bytes_to_frames(runtime, pos);
919 }
920
921 static const struct snd_pcm_hardware loopback_pcm_hardware =
922 {
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 SNDRV_PCM_FMTBIT_DSD_U8 |
932 SNDRV_PCM_FMTBIT_DSD_U16_LE | SNDRV_PCM_FMTBIT_DSD_U16_BE |
933 SNDRV_PCM_FMTBIT_DSD_U32_LE | SNDRV_PCM_FMTBIT_DSD_U32_BE),
934 .rates = SNDRV_PCM_RATE_CONTINUOUS | SNDRV_PCM_RATE_8000_768000,
935 .rate_min = 8000,
936 .rate_max = 768000,
937 .channels_min = 1,
938 .channels_max = 32,
939 .buffer_bytes_max = 2 * 1024 * 1024,
940 .period_bytes_min = 64,
941 /* note check overflow in frac_pos() using pcm_rate_shift before
942 changing period_bytes_max value */
943 .period_bytes_max = 1024 * 1024,
944 .periods_min = 1,
945 .periods_max = 1024,
946 .fifo_size = 0,
947 };
948
949 static void loopback_runtime_free(struct snd_pcm_runtime *runtime)
950 {
951 struct loopback_pcm *dpcm = runtime->private_data;
952 kfree(dpcm);
953 }
954
955 static int loopback_hw_free(struct snd_pcm_substream *substream)
956 {
957 struct snd_pcm_runtime *runtime = substream->runtime;
958 struct loopback_pcm *dpcm = runtime->private_data;
959 struct loopback_cable *cable = dpcm->cable;
960
961 mutex_lock(&dpcm->loopback->cable_lock);
962 cable->valid &= ~(1 << substream->stream);
963 mutex_unlock(&dpcm->loopback->cable_lock);
964 return 0;
965 }
966
967 static unsigned int get_cable_index(struct snd_pcm_substream *substream)
968 {
969 if (!substream->pcm->device)
970 return substream->stream;
971 else
972 return !substream->stream;
973 }
974
975 static int rule_format(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_mask m;
981
982 snd_mask_none(&m);
983 mutex_lock(&dpcm->loopback->cable_lock);
984 m.bits[0] = (u_int32_t)cable->hw.formats;
985 m.bits[1] = (u_int32_t)(cable->hw.formats >> 32);
986 mutex_unlock(&dpcm->loopback->cable_lock);
987 return snd_mask_refine(hw_param_mask(params, rule->var), &m);
988 }
989
990 static int rule_rate(struct snd_pcm_hw_params *params,
991 struct snd_pcm_hw_rule *rule)
992 {
993 struct loopback_pcm *dpcm = rule->private;
994 struct loopback_cable *cable = dpcm->cable;
995 struct snd_interval t;
996
997 mutex_lock(&dpcm->loopback->cable_lock);
998 t.min = cable->hw.rate_min;
999 t.max = cable->hw.rate_max;
1000 mutex_unlock(&dpcm->loopback->cable_lock);
1001 t.openmin = t.openmax = 0;
1002 t.integer = 0;
1003 return snd_interval_refine(hw_param_interval(params, rule->var), &t);
1004 }
1005
1006 static int rule_channels(struct snd_pcm_hw_params *params,
1007 struct snd_pcm_hw_rule *rule)
1008 {
1009 struct loopback_pcm *dpcm = rule->private;
1010 struct loopback_cable *cable = dpcm->cable;
1011 struct snd_interval t;
1012
1013 mutex_lock(&dpcm->loopback->cable_lock);
1014 t.min = cable->hw.channels_min;
1015 t.max = cable->hw.channels_max;
1016 mutex_unlock(&dpcm->loopback->cable_lock);
1017 t.openmin = t.openmax = 0;
1018 t.integer = 0;
1019 return snd_interval_refine(hw_param_interval(params, rule->var), &t);
1020 }
1021
1022 static int rule_period_bytes(struct snd_pcm_hw_params *params,
1023 struct snd_pcm_hw_rule *rule)
1024 {
1025 struct loopback_pcm *dpcm = rule->private;
1026 struct loopback_cable *cable = dpcm->cable;
1027 struct snd_interval t;
1028
1029 mutex_lock(&dpcm->loopback->cable_lock);
1030 t.min = cable->hw.period_bytes_min;
1031 t.max = cable->hw.period_bytes_max;
1032 mutex_unlock(&dpcm->loopback->cable_lock);
1033 t.openmin = 0;
1034 t.openmax = 0;
1035 t.integer = 0;
1036 return snd_interval_refine(hw_param_interval(params, rule->var), &t);
1037 }
1038
1039 static void free_cable(struct snd_pcm_substream *substream)
1040 {
1041 struct loopback *loopback = substream->private_data;
1042 int dev = get_cable_index(substream);
1043 struct loopback_cable *cable;
1044
1045 cable = loopback->cables[substream->number][dev];
1046 if (!cable)
1047 return;
1048 if (cable->streams[!substream->stream]) {
1049 /* other stream is still alive */
1050 spin_lock_irq(&cable->lock);
1051 cable->streams[substream->stream] = NULL;
1052 spin_unlock_irq(&cable->lock);
1053 } else {
1054 struct loopback_pcm *dpcm = substream->runtime->private_data;
1055
1056 if (cable->ops && cable->ops->close_cable && dpcm)
1057 cable->ops->close_cable(dpcm);
1058 /* free the cable */
1059 loopback->cables[substream->number][dev] = NULL;
1060 kfree(cable);
1061 }
1062 }
1063
1064 static int loopback_jiffies_timer_open(struct loopback_pcm *dpcm)
1065 {
1066 timer_setup(&dpcm->timer, loopback_jiffies_timer_function, 0);
1067
1068 return 0;
1069 }
1070
1071 static const struct loopback_ops loopback_jiffies_timer_ops = {
1072 .open = loopback_jiffies_timer_open,
1073 .start = loopback_jiffies_timer_start,
1074 .stop = loopback_jiffies_timer_stop,
1075 .stop_sync = loopback_jiffies_timer_stop_sync,
1076 .close_substream = loopback_jiffies_timer_stop_sync,
1077 .pos_update = loopback_jiffies_timer_pos_update,
1078 .dpcm_info = loopback_jiffies_timer_dpcm_info,
1079 };
1080
1081 static int loopback_parse_timer_id(const char *str,
1082 struct snd_timer_id *tid)
1083 {
1084 /* [<pref>:](<card name>|<card idx>)[{.,}<dev idx>[{.,}<subdev idx>]] */
1085 const char * const sep_dev = ".,";
1086 const char * const sep_pref = ":";
1087 const char *name = str;
1088 char *sep, save = '\0';
1089 int card_idx = 0, dev = 0, subdev = 0;
1090 int err;
1091
1092 sep = strpbrk(str, sep_pref);
1093 if (sep)
1094 name = sep + 1;
1095 sep = strpbrk(name, sep_dev);
1096 if (sep) {
1097 save = *sep;
1098 *sep = '\0';
1099 }
1100 err = kstrtoint(name, 0, &card_idx);
1101 if (err == -EINVAL) {
1102 /* Must be the name, not number */
1103 for (card_idx = 0; card_idx < snd_ecards_limit; card_idx++) {
1104 struct snd_card *card = snd_card_ref(card_idx);
1105
1106 if (card) {
1107 if (!strcmp(card->id, name))
1108 err = 0;
1109 snd_card_unref(card);
1110 }
1111 if (!err)
1112 break;
1113 }
1114 }
1115 if (sep) {
1116 *sep = save;
1117 if (!err) {
1118 char *sep2, save2 = '\0';
1119
1120 sep2 = strpbrk(sep + 1, sep_dev);
1121 if (sep2) {
1122 save2 = *sep2;
1123 *sep2 = '\0';
1124 }
1125 err = kstrtoint(sep + 1, 0, &dev);
1126 if (sep2) {
1127 *sep2 = save2;
1128 if (!err)
1129 err = kstrtoint(sep2 + 1, 0, &subdev);
1130 }
1131 }
1132 }
1133 if (!err && tid) {
1134 tid->card = card_idx;
1135 tid->device = dev;
1136 tid->subdevice = subdev;
1137 }
1138 return err;
1139 }
1140
1141 /* call in loopback->cable_lock */
1142 static int loopback_snd_timer_open(struct loopback_pcm *dpcm)
1143 {
1144 int err = 0;
1145 struct snd_timer_id tid = {
1146 .dev_class = SNDRV_TIMER_CLASS_PCM,
1147 .dev_sclass = SNDRV_TIMER_SCLASS_APPLICATION,
1148 };
1149 struct snd_timer_instance *timeri;
1150 struct loopback_cable *cable = dpcm->cable;
1151
1152 /* check if timer was already opened. It is only opened once
1153 * per playback and capture subdevice (aka cable).
1154 */
1155 if (cable->snd_timer.instance)
1156 goto exit;
1157
1158 err = loopback_parse_timer_id(dpcm->loopback->timer_source, &tid);
1159 if (err < 0) {
1160 pcm_err(dpcm->substream->pcm,
1161 "Parsing timer source \'%s\' failed with %d",
1162 dpcm->loopback->timer_source, err);
1163 goto exit;
1164 }
1165
1166 cable->snd_timer.stream = dpcm->substream->stream;
1167 cable->snd_timer.id = tid;
1168
1169 timeri = snd_timer_instance_new(dpcm->loopback->card->id);
1170 if (!timeri) {
1171 err = -ENOMEM;
1172 goto exit;
1173 }
1174 /* The callback has to be called from another work. If
1175 * SNDRV_TIMER_IFLG_FAST is specified it will be called from the
1176 * snd_pcm_period_elapsed() call of the selected sound card.
1177 * snd_pcm_period_elapsed() helds snd_pcm_stream_lock_irqsave().
1178 * Due to our callback loopback_snd_timer_function() also calls
1179 * snd_pcm_period_elapsed() which calls snd_pcm_stream_lock_irqsave().
1180 * This would end up in a dead lock.
1181 */
1182 timeri->flags |= SNDRV_TIMER_IFLG_AUTO;
1183 timeri->callback = loopback_snd_timer_function;
1184 timeri->callback_data = (void *)cable;
1185 timeri->ccallback = loopback_snd_timer_event;
1186
1187 /* initialise a work used for draining */
1188 INIT_WORK(&cable->snd_timer.event_work, loopback_snd_timer_work);
1189
1190 /* The mutex loopback->cable_lock is kept locked.
1191 * Therefore snd_timer_open() cannot be called a second time
1192 * by the other device of the same cable.
1193 * Therefore the following issue cannot happen:
1194 * [proc1] Call loopback_timer_open() ->
1195 * Unlock cable->lock for snd_timer_close/open() call
1196 * [proc2] Call loopback_timer_open() -> snd_timer_open(),
1197 * snd_timer_start()
1198 * [proc1] Call snd_timer_open() and overwrite running timer
1199 * instance
1200 */
1201 err = snd_timer_open(timeri, &cable->snd_timer.id, current->pid);
1202 if (err < 0) {
1203 pcm_err(dpcm->substream->pcm,
1204 "snd_timer_open (%d,%d,%d) failed with %d",
1205 cable->snd_timer.id.card,
1206 cable->snd_timer.id.device,
1207 cable->snd_timer.id.subdevice,
1208 err);
1209 snd_timer_instance_free(timeri);
1210 goto exit;
1211 }
1212
1213 cable->snd_timer.instance = timeri;
1214
1215 exit:
1216 return err;
1217 }
1218
1219 /* stop_sync() is not required for sound timer because it does not need to be
1220 * restarted in loopback_prepare() on Xrun recovery
1221 */
1222 static const struct loopback_ops loopback_snd_timer_ops = {
1223 .open = loopback_snd_timer_open,
1224 .start = loopback_snd_timer_start,
1225 .stop = loopback_snd_timer_stop,
1226 .close_cable = loopback_snd_timer_close_cable,
1227 .dpcm_info = loopback_snd_timer_dpcm_info,
1228 };
1229
1230 static int loopback_open(struct snd_pcm_substream *substream)
1231 {
1232 struct snd_pcm_runtime *runtime = substream->runtime;
1233 struct loopback *loopback = substream->private_data;
1234 struct loopback_pcm *dpcm;
1235 struct loopback_cable *cable = NULL;
1236 int err = 0;
1237 int dev = get_cable_index(substream);
1238
1239 mutex_lock(&loopback->cable_lock);
1240 dpcm = kzalloc(sizeof(*dpcm), GFP_KERNEL);
1241 if (!dpcm) {
1242 err = -ENOMEM;
1243 goto unlock;
1244 }
1245 dpcm->loopback = loopback;
1246 dpcm->substream = substream;
1247
1248 cable = loopback->cables[substream->number][dev];
1249 if (!cable) {
1250 cable = kzalloc(sizeof(*cable), GFP_KERNEL);
1251 if (!cable) {
1252 err = -ENOMEM;
1253 goto unlock;
1254 }
1255 spin_lock_init(&cable->lock);
1256 cable->hw = loopback_pcm_hardware;
1257 if (loopback->timer_source)
1258 cable->ops = &loopback_snd_timer_ops;
1259 else
1260 cable->ops = &loopback_jiffies_timer_ops;
1261 loopback->cables[substream->number][dev] = cable;
1262 }
1263 dpcm->cable = cable;
1264 runtime->private_data = dpcm;
1265
1266 if (cable->ops->open) {
1267 err = cable->ops->open(dpcm);
1268 if (err < 0)
1269 goto unlock;
1270 }
1271
1272 snd_pcm_hw_constraint_integer(runtime, SNDRV_PCM_HW_PARAM_PERIODS);
1273
1274 /* use dynamic rules based on actual runtime->hw values */
1275 /* note that the default rules created in the PCM midlevel code */
1276 /* are cached -> they do not reflect the actual state */
1277 err = snd_pcm_hw_rule_add(runtime, 0,
1278 SNDRV_PCM_HW_PARAM_FORMAT,
1279 rule_format, dpcm,
1280 SNDRV_PCM_HW_PARAM_FORMAT, -1);
1281 if (err < 0)
1282 goto unlock;
1283 err = snd_pcm_hw_rule_add(runtime, 0,
1284 SNDRV_PCM_HW_PARAM_RATE,
1285 rule_rate, dpcm,
1286 SNDRV_PCM_HW_PARAM_RATE, -1);
1287 if (err < 0)
1288 goto unlock;
1289 err = snd_pcm_hw_rule_add(runtime, 0,
1290 SNDRV_PCM_HW_PARAM_CHANNELS,
1291 rule_channels, dpcm,
1292 SNDRV_PCM_HW_PARAM_CHANNELS, -1);
1293 if (err < 0)
1294 goto unlock;
1295
1296 /* In case of sound timer the period time of both devices of the same
1297 * loop has to be the same.
1298 * This rule only takes effect if a sound timer was chosen
1299 */
1300 if (cable->snd_timer.instance) {
1301 err = snd_pcm_hw_rule_add(runtime, 0,
1302 SNDRV_PCM_HW_PARAM_PERIOD_BYTES,
1303 rule_period_bytes, dpcm,
1304 SNDRV_PCM_HW_PARAM_PERIOD_BYTES, -1);
1305 if (err < 0)
1306 goto unlock;
1307 }
1308
1309 /* loopback_runtime_free() has not to be called if kfree(dpcm) was
1310 * already called here. Otherwise it will end up with a double free.
1311 */
1312 runtime->private_free = loopback_runtime_free;
1313 if (get_notify(dpcm))
1314 runtime->hw = loopback_pcm_hardware;
1315 else
1316 runtime->hw = cable->hw;
1317
1318 spin_lock_irq(&cable->lock);
1319 cable->streams[substream->stream] = dpcm;
1320 spin_unlock_irq(&cable->lock);
1321
1322 unlock:
1323 if (err < 0) {
1324 free_cable(substream);
1325 kfree(dpcm);
1326 }
1327 mutex_unlock(&loopback->cable_lock);
1328 return err;
1329 }
1330
1331 static int loopback_close(struct snd_pcm_substream *substream)
1332 {
1333 struct loopback *loopback = substream->private_data;
1334 struct loopback_pcm *dpcm = substream->runtime->private_data;
1335 int err = 0;
1336
1337 if (dpcm->cable->ops->close_substream)
1338 err = dpcm->cable->ops->close_substream(dpcm);
1339 mutex_lock(&loopback->cable_lock);
1340 free_cable(substream);
1341 mutex_unlock(&loopback->cable_lock);
1342 return err;
1343 }
1344
1345 static const struct snd_pcm_ops loopback_pcm_ops = {
1346 .open = loopback_open,
1347 .close = loopback_close,
1348 .hw_free = loopback_hw_free,
1349 .prepare = loopback_prepare,
1350 .trigger = loopback_trigger,
1351 .pointer = loopback_pointer,
1352 };
1353
1354 static int loopback_pcm_new(struct loopback *loopback,
1355 int device, int substreams)
1356 {
1357 struct snd_pcm *pcm;
1358 int err;
1359
1360 err = snd_pcm_new(loopback->card, "Loopback PCM", device,
1361 substreams, substreams, &pcm);
1362 if (err < 0)
1363 return err;
1364 snd_pcm_set_ops(pcm, SNDRV_PCM_STREAM_PLAYBACK, &loopback_pcm_ops);
1365 snd_pcm_set_ops(pcm, SNDRV_PCM_STREAM_CAPTURE, &loopback_pcm_ops);
1366 snd_pcm_set_managed_buffer_all(pcm, SNDRV_DMA_TYPE_VMALLOC, NULL, 0, 0);
1367
1368 pcm->private_data = loopback;
1369 pcm->info_flags = 0;
1370 strcpy(pcm->name, "Loopback PCM");
1371
1372 loopback->pcm[device] = pcm;
1373 return 0;
1374 }
1375
1376 static int loopback_rate_shift_info(struct snd_kcontrol *kcontrol,
1377 struct snd_ctl_elem_info *uinfo)
1378 {
1379 uinfo->type = SNDRV_CTL_ELEM_TYPE_INTEGER;
1380 uinfo->count = 1;
1381 uinfo->value.integer.min = 80000;
1382 uinfo->value.integer.max = 120000;
1383 uinfo->value.integer.step = 1;
1384 return 0;
1385 }
1386
1387 static int loopback_rate_shift_get(struct snd_kcontrol *kcontrol,
1388 struct snd_ctl_elem_value *ucontrol)
1389 {
1390 struct loopback *loopback = snd_kcontrol_chip(kcontrol);
1391
1392 mutex_lock(&loopback->cable_lock);
1393 ucontrol->value.integer.value[0] =
1394 loopback->setup[kcontrol->id.subdevice]
1395 [kcontrol->id.device].rate_shift;
1396 mutex_unlock(&loopback->cable_lock);
1397 return 0;
1398 }
1399
1400 static int loopback_rate_shift_put(struct snd_kcontrol *kcontrol,
1401 struct snd_ctl_elem_value *ucontrol)
1402 {
1403 struct loopback *loopback = snd_kcontrol_chip(kcontrol);
1404 unsigned int val;
1405 int change = 0;
1406
1407 val = ucontrol->value.integer.value[0];
1408 if (val < 80000)
1409 val = 80000;
1410 if (val > 120000)
1411 val = 120000;
1412 mutex_lock(&loopback->cable_lock);
1413 if (val != loopback->setup[kcontrol->id.subdevice]
1414 [kcontrol->id.device].rate_shift) {
1415 loopback->setup[kcontrol->id.subdevice]
1416 [kcontrol->id.device].rate_shift = val;
1417 change = 1;
1418 }
1419 mutex_unlock(&loopback->cable_lock);
1420 return change;
1421 }
1422
1423 static int loopback_notify_get(struct snd_kcontrol *kcontrol,
1424 struct snd_ctl_elem_value *ucontrol)
1425 {
1426 struct loopback *loopback = snd_kcontrol_chip(kcontrol);
1427
1428 mutex_lock(&loopback->cable_lock);
1429 ucontrol->value.integer.value[0] =
1430 loopback->setup[kcontrol->id.subdevice]
1431 [kcontrol->id.device].notify;
1432 mutex_unlock(&loopback->cable_lock);
1433 return 0;
1434 }
1435
1436 static int loopback_notify_put(struct snd_kcontrol *kcontrol,
1437 struct snd_ctl_elem_value *ucontrol)
1438 {
1439 struct loopback *loopback = snd_kcontrol_chip(kcontrol);
1440 unsigned int val;
1441 int change = 0;
1442
1443 val = ucontrol->value.integer.value[0] ? 1 : 0;
1444 mutex_lock(&loopback->cable_lock);
1445 if (val != loopback->setup[kcontrol->id.subdevice]
1446 [kcontrol->id.device].notify) {
1447 loopback->setup[kcontrol->id.subdevice]
1448 [kcontrol->id.device].notify = val;
1449 change = 1;
1450 }
1451 mutex_unlock(&loopback->cable_lock);
1452 return change;
1453 }
1454
1455 static int loopback_active_get(struct snd_kcontrol *kcontrol,
1456 struct snd_ctl_elem_value *ucontrol)
1457 {
1458 struct loopback *loopback = snd_kcontrol_chip(kcontrol);
1459 struct loopback_cable *cable;
1460
1461 unsigned int val = 0;
1462
1463 mutex_lock(&loopback->cable_lock);
1464 cable = loopback->cables[kcontrol->id.subdevice][kcontrol->id.device ^ 1];
1465 if (cable != NULL) {
1466 unsigned int running = cable->running ^ cable->pause;
1467
1468 val = (running & (1 << SNDRV_PCM_STREAM_PLAYBACK)) ? 1 : 0;
1469 }
1470 mutex_unlock(&loopback->cable_lock);
1471 ucontrol->value.integer.value[0] = val;
1472 return 0;
1473 }
1474
1475 static int loopback_format_info(struct snd_kcontrol *kcontrol,
1476 struct snd_ctl_elem_info *uinfo)
1477 {
1478 uinfo->type = SNDRV_CTL_ELEM_TYPE_INTEGER;
1479 uinfo->count = 1;
1480 uinfo->value.integer.min = 0;
1481 uinfo->value.integer.max = (__force int)SNDRV_PCM_FORMAT_LAST;
1482 uinfo->value.integer.step = 1;
1483 return 0;
1484 }
1485
1486 static int loopback_format_get(struct snd_kcontrol *kcontrol,
1487 struct snd_ctl_elem_value *ucontrol)
1488 {
1489 struct loopback *loopback = snd_kcontrol_chip(kcontrol);
1490
1491 ucontrol->value.integer.value[0] =
1492 (__force int)loopback->setup[kcontrol->id.subdevice]
1493 [kcontrol->id.device].format;
1494 return 0;
1495 }
1496
1497 static int loopback_rate_info(struct snd_kcontrol *kcontrol,
1498 struct snd_ctl_elem_info *uinfo)
1499 {
1500 uinfo->type = SNDRV_CTL_ELEM_TYPE_INTEGER;
1501 uinfo->count = 1;
1502 uinfo->value.integer.min = 0;
1503 uinfo->value.integer.max = 192000;
1504 uinfo->value.integer.step = 1;
1505 return 0;
1506 }
1507
1508 static int loopback_rate_get(struct snd_kcontrol *kcontrol,
1509 struct snd_ctl_elem_value *ucontrol)
1510 {
1511 struct loopback *loopback = snd_kcontrol_chip(kcontrol);
1512
1513 mutex_lock(&loopback->cable_lock);
1514 ucontrol->value.integer.value[0] =
1515 loopback->setup[kcontrol->id.subdevice]
1516 [kcontrol->id.device].rate;
1517 mutex_unlock(&loopback->cable_lock);
1518 return 0;
1519 }
1520
1521 static int loopback_channels_info(struct snd_kcontrol *kcontrol,
1522 struct snd_ctl_elem_info *uinfo)
1523 {
1524 uinfo->type = SNDRV_CTL_ELEM_TYPE_INTEGER;
1525 uinfo->count = 1;
1526 uinfo->value.integer.min = 1;
1527 uinfo->value.integer.max = 1024;
1528 uinfo->value.integer.step = 1;
1529 return 0;
1530 }
1531
1532 static int loopback_channels_get(struct snd_kcontrol *kcontrol,
1533 struct snd_ctl_elem_value *ucontrol)
1534 {
1535 struct loopback *loopback = snd_kcontrol_chip(kcontrol);
1536
1537 mutex_lock(&loopback->cable_lock);
1538 ucontrol->value.integer.value[0] =
1539 loopback->setup[kcontrol->id.subdevice]
1540 [kcontrol->id.device].channels;
1541 mutex_unlock(&loopback->cable_lock);
1542 return 0;
1543 }
1544
1545 static int loopback_access_info(struct snd_kcontrol *kcontrol,
1546 struct snd_ctl_elem_info *uinfo)
1547 {
1548 const char * const texts[] = {"Interleaved", "Non-interleaved"};
1549
1550 return snd_ctl_enum_info(uinfo, 1, ARRAY_SIZE(texts), texts);
1551 }
1552
1553 static int loopback_access_get(struct snd_kcontrol *kcontrol,
1554 struct snd_ctl_elem_value *ucontrol)
1555 {
1556 struct loopback *loopback = snd_kcontrol_chip(kcontrol);
1557 snd_pcm_access_t access;
1558
1559 mutex_lock(&loopback->cable_lock);
1560 access = loopback->setup[kcontrol->id.subdevice][kcontrol->id.device].access;
1561
1562 ucontrol->value.enumerated.item[0] = !is_access_interleaved(access);
1563
1564 mutex_unlock(&loopback->cable_lock);
1565 return 0;
1566 }
1567
1568 static const struct snd_kcontrol_new loopback_controls[] = {
1569 {
1570 .iface = SNDRV_CTL_ELEM_IFACE_PCM,
1571 .name = "PCM Rate Shift 100000",
1572 .info = loopback_rate_shift_info,
1573 .get = loopback_rate_shift_get,
1574 .put = loopback_rate_shift_put,
1575 },
1576 {
1577 .iface = SNDRV_CTL_ELEM_IFACE_PCM,
1578 .name = "PCM Notify",
1579 .info = snd_ctl_boolean_mono_info,
1580 .get = loopback_notify_get,
1581 .put = loopback_notify_put,
1582 },
1583 #define ACTIVE_IDX 2
1584 {
1585 .access = SNDRV_CTL_ELEM_ACCESS_READ,
1586 .iface = SNDRV_CTL_ELEM_IFACE_PCM,
1587 .name = "PCM Slave Active",
1588 .info = snd_ctl_boolean_mono_info,
1589 .get = loopback_active_get,
1590 },
1591 #define FORMAT_IDX 3
1592 {
1593 .access = SNDRV_CTL_ELEM_ACCESS_READ,
1594 .iface = SNDRV_CTL_ELEM_IFACE_PCM,
1595 .name = "PCM Slave Format",
1596 .info = loopback_format_info,
1597 .get = loopback_format_get
1598 },
1599 #define RATE_IDX 4
1600 {
1601 .access = SNDRV_CTL_ELEM_ACCESS_READ,
1602 .iface = SNDRV_CTL_ELEM_IFACE_PCM,
1603 .name = "PCM Slave Rate",
1604 .info = loopback_rate_info,
1605 .get = loopback_rate_get
1606 },
1607 #define CHANNELS_IDX 5
1608 {
1609 .access = SNDRV_CTL_ELEM_ACCESS_READ,
1610 .iface = SNDRV_CTL_ELEM_IFACE_PCM,
1611 .name = "PCM Slave Channels",
1612 .info = loopback_channels_info,
1613 .get = loopback_channels_get
1614 },
1615 #define ACCESS_IDX 6
1616 {
1617 .access = SNDRV_CTL_ELEM_ACCESS_READ,
1618 .iface = SNDRV_CTL_ELEM_IFACE_PCM,
1619 .name = "PCM Slave Access Mode",
1620 .info = loopback_access_info,
1621 .get = loopback_access_get,
1622 },
1623 };
1624
1625 static int loopback_mixer_new(struct loopback *loopback, int notify)
1626 {
1627 struct snd_card *card = loopback->card;
1628 struct snd_pcm *pcm;
1629 struct snd_kcontrol *kctl;
1630 struct loopback_setup *setup;
1631 int err, dev, substr, substr_count, idx;
1632
1633 strcpy(card->mixername, "Loopback Mixer");
1634 for (dev = 0; dev < 2; dev++) {
1635 pcm = loopback->pcm[dev];
1636 substr_count =
1637 pcm->streams[SNDRV_PCM_STREAM_CAPTURE].substream_count;
1638 for (substr = 0; substr < substr_count; substr++) {
1639 setup = &loopback->setup[substr][dev];
1640 setup->notify = notify;
1641 setup->rate_shift = NO_PITCH;
1642 setup->format = SNDRV_PCM_FORMAT_S16_LE;
1643 setup->access = SNDRV_PCM_ACCESS_RW_INTERLEAVED;
1644 setup->rate = 48000;
1645 setup->channels = 2;
1646 for (idx = 0; idx < ARRAY_SIZE(loopback_controls);
1647 idx++) {
1648 kctl = snd_ctl_new1(&loopback_controls[idx],
1649 loopback);
1650 if (!kctl)
1651 return -ENOMEM;
1652 kctl->id.device = dev;
1653 kctl->id.subdevice = substr;
1654
1655 /* Add the control before copying the id so that
1656 * the numid field of the id is set in the copy.
1657 */
1658 err = snd_ctl_add(card, kctl);
1659 if (err < 0)
1660 return err;
1661
1662 switch (idx) {
1663 case ACTIVE_IDX:
1664 setup->active_id = kctl->id;
1665 break;
1666 case FORMAT_IDX:
1667 setup->format_id = kctl->id;
1668 break;
1669 case RATE_IDX:
1670 setup->rate_id = kctl->id;
1671 break;
1672 case CHANNELS_IDX:
1673 setup->channels_id = kctl->id;
1674 break;
1675 case ACCESS_IDX:
1676 setup->access_id = kctl->id;
1677 break;
1678 default:
1679 break;
1680 }
1681 }
1682 }
1683 }
1684 return 0;
1685 }
1686
1687 static void print_dpcm_info(struct snd_info_buffer *buffer,
1688 struct loopback_pcm *dpcm,
1689 const char *id)
1690 {
1691 snd_iprintf(buffer, " %s\n", id);
1692 if (dpcm == NULL) {
1693 snd_iprintf(buffer, " inactive\n");
1694 return;
1695 }
1696 snd_iprintf(buffer, " buffer_size:\t%u\n", dpcm->pcm_buffer_size);
1697 snd_iprintf(buffer, " buffer_pos:\t\t%u\n", dpcm->buf_pos);
1698 snd_iprintf(buffer, " silent_size:\t%u\n", dpcm->silent_size);
1699 snd_iprintf(buffer, " period_size:\t%u\n", dpcm->pcm_period_size);
1700 snd_iprintf(buffer, " bytes_per_sec:\t%u\n", dpcm->pcm_bps);
1701 snd_iprintf(buffer, " sample_align:\t%u\n", dpcm->pcm_salign);
1702 snd_iprintf(buffer, " rate_shift:\t\t%u\n", dpcm->pcm_rate_shift);
1703 if (dpcm->cable->ops->dpcm_info)
1704 dpcm->cable->ops->dpcm_info(dpcm, buffer);
1705 }
1706
1707 static void print_substream_info(struct snd_info_buffer *buffer,
1708 struct loopback *loopback,
1709 int sub,
1710 int num)
1711 {
1712 struct loopback_cable *cable = loopback->cables[sub][num];
1713
1714 snd_iprintf(buffer, "Cable %i substream %i:\n", num, sub);
1715 if (cable == NULL) {
1716 snd_iprintf(buffer, " inactive\n");
1717 return;
1718 }
1719 snd_iprintf(buffer, " valid: %u\n", cable->valid);
1720 snd_iprintf(buffer, " running: %u\n", cable->running);
1721 snd_iprintf(buffer, " pause: %u\n", cable->pause);
1722 print_dpcm_info(buffer, cable->streams[0], "Playback");
1723 print_dpcm_info(buffer, cable->streams[1], "Capture");
1724 }
1725
1726 static void print_cable_info(struct snd_info_entry *entry,
1727 struct snd_info_buffer *buffer)
1728 {
1729 struct loopback *loopback = entry->private_data;
1730 int sub, num;
1731
1732 mutex_lock(&loopback->cable_lock);
1733 num = entry->name[strlen(entry->name)-1];
1734 num = num == '' ? 0 : 1;
1735 for (sub = 0; sub < MAX_PCM_SUBSTREAMS; sub++)
1736 print_substream_info(buffer, loopback, sub, num);
1737 mutex_unlock(&loopback->cable_lock);
1738 }
1739
1740 static int loopback_cable_proc_new(struct loopback *loopback, int cidx)
1741 {
1742 char name[32];
1743
1744 snprintf(name, sizeof(name), "cable#%d", cidx);
1745 return snd_card_ro_proc_new(loopback->card, name, loopback,
1746 print_cable_info);
1747 }
1748
1749 static void loopback_set_timer_source(struct loopback *loopback,
1750 const char *value)
1751 {
1752 if (loopback->timer_source) {
1753 devm_kfree(loopback->card->dev, loopback->timer_source);
1754 loopback->timer_source = NULL;
1755 }
1756 if (value && *value)
1757 loopback->timer_source = devm_kstrdup(loopback->card->dev,
1758 value, GFP_KERNEL);
1759 }
1760
1761 static void print_timer_source_info(struct snd_info_entry *entry,
1762 struct snd_info_buffer *buffer)
1763 {
1764 struct loopback *loopback = entry->private_data;
1765
1766 mutex_lock(&loopback->cable_lock);
1767 snd_iprintf(buffer, "%s\n",
1768 loopback->timer_source ? loopback->timer_source : "");
1769 mutex_unlock(&loopback->cable_lock);
1770 }
1771
1772 static void change_timer_source_info(struct snd_info_entry *entry,
1773 struct snd_info_buffer *buffer)
1774 {
1775 struct loopback *loopback = entry->private_data;
1776 char line[64];
1777
1778 mutex_lock(&loopback->cable_lock);
1779 if (!snd_info_get_line(buffer, line, sizeof(line)))
1780 loopback_set_timer_source(loopback, strim(line));
1781 mutex_unlock(&loopback->cable_lock);
1782 }
1783
1784 static int loopback_timer_source_proc_new(struct loopback *loopback)
1785 {
1786 return snd_card_rw_proc_new(loopback->card, "timer_source", loopback,
1787 print_timer_source_info,
1788 change_timer_source_info);
1789 }
1790
1791 static int loopback_probe(struct platform_device *devptr)
1792 {
1793 struct snd_card *card;
1794 struct loopback *loopback;
1795 int dev = devptr->id;
1796 int err;
1797
1798 err = snd_devm_card_new(&devptr->dev, index[dev], id[dev], THIS_MODULE,
1799 sizeof(struct loopback), &card);
1800 if (err < 0)
1801 return err;
1802 loopback = card->private_data;
1803
1804 if (pcm_substreams[dev] < 1)
1805 pcm_substreams[dev] = 1;
1806 if (pcm_substreams[dev] > MAX_PCM_SUBSTREAMS)
1807 pcm_substreams[dev] = MAX_PCM_SUBSTREAMS;
1808
1809 loopback->card = card;
1810 loopback_set_timer_source(loopback, timer_source[dev]);
1811
1812 mutex_init(&loopback->cable_lock);
1813
1814 err = loopback_pcm_new(loopback, 0, pcm_substreams[dev]);
1815 if (err < 0)
1816 return err;
1817 err = loopback_pcm_new(loopback, 1, pcm_substreams[dev]);
1818 if (err < 0)
1819 return err;
1820 err = loopback_mixer_new(loopback, pcm_notify[dev] ? 1 : 0);
1821 if (err < 0)
1822 return err;
1823 loopback_cable_proc_new(loopback, 0);
1824 loopback_cable_proc_new(loopback, 1);
1825 loopback_timer_source_proc_new(loopback);
1826 strcpy(card->driver, "Loopback");
1827 strcpy(card->shortname, "Loopback");
1828 sprintf(card->longname, "Loopback %i", dev + 1);
1829 err = snd_card_register(card);
1830 if (err < 0)
1831 return err;
1832 platform_set_drvdata(devptr, card);
1833 return 0;
1834 }
1835
1836 static int loopback_suspend(struct device *pdev)
1837 {
1838 struct snd_card *card = dev_get_drvdata(pdev);
1839
1840 snd_power_change_state(card, SNDRV_CTL_POWER_D3hot);
1841 return 0;
1842 }
1843
1844 static int loopback_resume(struct device *pdev)
1845 {
1846 struct snd_card *card = dev_get_drvdata(pdev);
1847
1848 snd_power_change_state(card, SNDRV_CTL_POWER_D0);
1849 return 0;
1850 }
1851
1852 static DEFINE_SIMPLE_DEV_PM_OPS(loopback_pm, loopback_suspend, loopback_resume);
1853
1854 #define SND_LOOPBACK_DRIVER "snd_aloop"
1855
1856 static struct platform_driver loopback_driver = {
1857 .probe = loopback_probe,
1858 .driver = {
1859 .name = SND_LOOPBACK_DRIVER,
1860 .pm = &loopback_pm,
1861 },
1862 };
1863
1864 static void loopback_unregister_all(void)
1865 {
1866 int i;
1867
1868 for (i = 0; i < ARRAY_SIZE(devices); ++i)
1869 platform_device_unregister(devices[i]);
1870 platform_driver_unregister(&loopback_driver);
1871 }
1872
1873 static int __init alsa_card_loopback_init(void)
1874 {
1875 int i, err, cards;
1876
1877 err = platform_driver_register(&loopback_driver);
1878 if (err < 0)
1879 return err;
1880
1881
1882 cards = 0;
1883 for (i = 0; i < SNDRV_CARDS; i++) {
1884 struct platform_device *device;
1885 if (!enable[i])
1886 continue;
1887 device = platform_device_register_simple(SND_LOOPBACK_DRIVER,
1888 i, NULL, 0);
1889 if (IS_ERR(device))
1890 continue;
1891 if (!platform_get_drvdata(device)) {
1892 platform_device_unregister(device);
1893 continue;
1894 }
1895 devices[i] = device;
1896 cards++;
1897 }
1898 if (!cards) {
1899 #ifdef MODULE
1900 printk(KERN_ERR "aloop: No loopback enabled\n");
1901 #endif
1902 loopback_unregister_all();
1903 return -ENODEV;
1904 }
1905 return 0;
1906 }
1907
1908 static void __exit alsa_card_loopback_exit(void)
1909 {
1910 loopback_unregister_all();
1911 }
1912
1913 module_init(alsa_card_loopback_init)
1914 module_exit(alsa_card_loopback_exit)
1915
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