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Merge tag 'vfio-v4.16-rc7' of git://github.com/awilliam/linux-vfio
[mirror_ubuntu-hirsute-kernel.git] / sound / drivers / aloop.c
1 /*
2 * Loopback soundcard
3 *
4 * Original code:
5 * Copyright (c) by Jaroslav Kysela <perex@perex.cz>
6 *
7 * More accurate positioning and full-duplex support:
8 * Copyright (c) Ahmet İnan <ainan at mathematik.uni-freiburg.de>
9 *
10 * Major (almost complete) rewrite:
11 * Copyright (c) by Takashi Iwai <tiwai@suse.de>
12 *
13 * A next major update in 2010 (separate timers for playback and capture):
14 * Copyright (c) Jaroslav Kysela <perex@perex.cz>
15 *
16 * This program is free software; you can redistribute it and/or modify
17 * it under the terms of the GNU General Public License as published by
18 * the Free Software Foundation; either version 2 of the License, or
19 * (at your option) any later version.
20 *
21 * This program is distributed in the hope that it will be useful,
22 * but WITHOUT ANY WARRANTY; without even the implied warranty of
23 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
24 * GNU General Public License for more details.
25 *
26 * You should have received a copy of the GNU General Public License
27 * along with this program; if not, write to the Free Software
28 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
29 *
30 */
31
32 #include <linux/init.h>
33 #include <linux/jiffies.h>
34 #include <linux/slab.h>
35 #include <linux/time.h>
36 #include <linux/wait.h>
37 #include <linux/module.h>
38 #include <linux/platform_device.h>
39 #include <sound/core.h>
40 #include <sound/control.h>
41 #include <sound/pcm.h>
42 #include <sound/pcm_params.h>
43 #include <sound/info.h>
44 #include <sound/initval.h>
45
46 MODULE_AUTHOR("Jaroslav Kysela <perex@perex.cz>");
47 MODULE_DESCRIPTION("A loopback soundcard");
48 MODULE_LICENSE("GPL");
49 MODULE_SUPPORTED_DEVICE("{{ALSA,Loopback soundcard}}");
50
51 #define MAX_PCM_SUBSTREAMS 8
52
53 static int index[SNDRV_CARDS] = SNDRV_DEFAULT_IDX; /* Index 0-MAX */
54 static char *id[SNDRV_CARDS] = SNDRV_DEFAULT_STR; /* ID for this card */
55 static bool enable[SNDRV_CARDS] = {1, [1 ... (SNDRV_CARDS - 1)] = 0};
56 static int pcm_substreams[SNDRV_CARDS] = {[0 ... (SNDRV_CARDS - 1)] = 8};
57 static int pcm_notify[SNDRV_CARDS];
58
59 module_param_array(index, int, NULL, 0444);
60 MODULE_PARM_DESC(index, "Index value for loopback soundcard.");
61 module_param_array(id, charp, NULL, 0444);
62 MODULE_PARM_DESC(id, "ID string for loopback soundcard.");
63 module_param_array(enable, bool, NULL, 0444);
64 MODULE_PARM_DESC(enable, "Enable this loopback soundcard.");
65 module_param_array(pcm_substreams, int, NULL, 0444);
66 MODULE_PARM_DESC(pcm_substreams, "PCM substreams # (1-8) for loopback driver.");
67 module_param_array(pcm_notify, int, NULL, 0444);
68 MODULE_PARM_DESC(pcm_notify, "Break capture when PCM format/rate/channels changes.");
69
70 #define NO_PITCH 100000
71
72 struct loopback_pcm;
73
74 struct loopback_cable {
75 spinlock_t lock;
76 struct loopback_pcm *streams[2];
77 struct snd_pcm_hardware hw;
78 /* flags */
79 unsigned int valid;
80 unsigned int running;
81 unsigned int pause;
82 };
83
84 struct loopback_setup {
85 unsigned int notify: 1;
86 unsigned int rate_shift;
87 unsigned int format;
88 unsigned int rate;
89 unsigned int channels;
90 struct snd_ctl_elem_id active_id;
91 struct snd_ctl_elem_id format_id;
92 struct snd_ctl_elem_id rate_id;
93 struct snd_ctl_elem_id channels_id;
94 };
95
96 struct loopback {
97 struct snd_card *card;
98 struct mutex cable_lock;
99 struct loopback_cable *cables[MAX_PCM_SUBSTREAMS][2];
100 struct snd_pcm *pcm[2];
101 struct loopback_setup setup[MAX_PCM_SUBSTREAMS][2];
102 };
103
104 struct loopback_pcm {
105 struct loopback *loopback;
106 struct snd_pcm_substream *substream;
107 struct loopback_cable *cable;
108 unsigned int pcm_buffer_size;
109 unsigned int buf_pos; /* position in buffer */
110 unsigned int silent_size;
111 /* PCM parameters */
112 unsigned int pcm_period_size;
113 unsigned int pcm_bps; /* bytes per second */
114 unsigned int pcm_salign; /* bytes per sample * channels */
115 unsigned int pcm_rate_shift; /* rate shift value */
116 /* flags */
117 unsigned int period_update_pending :1;
118 /* timer stuff */
119 unsigned int irq_pos; /* fractional IRQ position */
120 unsigned int period_size_frac;
121 unsigned int last_drift;
122 unsigned long last_jiffies;
123 struct timer_list timer;
124 };
125
126 static struct platform_device *devices[SNDRV_CARDS];
127
128 static inline unsigned int byte_pos(struct loopback_pcm *dpcm, unsigned int x)
129 {
130 if (dpcm->pcm_rate_shift == NO_PITCH) {
131 x /= HZ;
132 } else {
133 x = div_u64(NO_PITCH * (unsigned long long)x,
134 HZ * (unsigned long long)dpcm->pcm_rate_shift);
135 }
136 return x - (x % dpcm->pcm_salign);
137 }
138
139 static inline unsigned int frac_pos(struct loopback_pcm *dpcm, unsigned int x)
140 {
141 if (dpcm->pcm_rate_shift == NO_PITCH) { /* no pitch */
142 return x * HZ;
143 } else {
144 x = div_u64(dpcm->pcm_rate_shift * (unsigned long long)x * HZ,
145 NO_PITCH);
146 }
147 return x;
148 }
149
150 static inline struct loopback_setup *get_setup(struct loopback_pcm *dpcm)
151 {
152 int device = dpcm->substream->pstr->pcm->device;
153
154 if (dpcm->substream->stream == SNDRV_PCM_STREAM_PLAYBACK)
155 device ^= 1;
156 return &dpcm->loopback->setup[dpcm->substream->number][device];
157 }
158
159 static inline unsigned int get_notify(struct loopback_pcm *dpcm)
160 {
161 return get_setup(dpcm)->notify;
162 }
163
164 static inline unsigned int get_rate_shift(struct loopback_pcm *dpcm)
165 {
166 return get_setup(dpcm)->rate_shift;
167 }
168
169 /* call in cable->lock */
170 static void loopback_timer_start(struct loopback_pcm *dpcm)
171 {
172 unsigned long tick;
173 unsigned int rate_shift = get_rate_shift(dpcm);
174
175 if (rate_shift != dpcm->pcm_rate_shift) {
176 dpcm->pcm_rate_shift = rate_shift;
177 dpcm->period_size_frac = frac_pos(dpcm, dpcm->pcm_period_size);
178 }
179 if (dpcm->period_size_frac <= dpcm->irq_pos) {
180 dpcm->irq_pos %= dpcm->period_size_frac;
181 dpcm->period_update_pending = 1;
182 }
183 tick = dpcm->period_size_frac - dpcm->irq_pos;
184 tick = (tick + dpcm->pcm_bps - 1) / dpcm->pcm_bps;
185 mod_timer(&dpcm->timer, jiffies + tick);
186 }
187
188 /* call in cable->lock */
189 static inline void loopback_timer_stop(struct loopback_pcm *dpcm)
190 {
191 del_timer(&dpcm->timer);
192 dpcm->timer.expires = 0;
193 }
194
195 static inline void loopback_timer_stop_sync(struct loopback_pcm *dpcm)
196 {
197 del_timer_sync(&dpcm->timer);
198 }
199
200 #define CABLE_VALID_PLAYBACK (1 << SNDRV_PCM_STREAM_PLAYBACK)
201 #define CABLE_VALID_CAPTURE (1 << SNDRV_PCM_STREAM_CAPTURE)
202 #define CABLE_VALID_BOTH (CABLE_VALID_PLAYBACK|CABLE_VALID_CAPTURE)
203
204 static int loopback_check_format(struct loopback_cable *cable, int stream)
205 {
206 struct snd_pcm_runtime *runtime, *cruntime;
207 struct loopback_setup *setup;
208 struct snd_card *card;
209 int check;
210
211 if (cable->valid != CABLE_VALID_BOTH) {
212 if (stream == SNDRV_PCM_STREAM_PLAYBACK)
213 goto __notify;
214 return 0;
215 }
216 runtime = cable->streams[SNDRV_PCM_STREAM_PLAYBACK]->
217 substream->runtime;
218 cruntime = cable->streams[SNDRV_PCM_STREAM_CAPTURE]->
219 substream->runtime;
220 check = runtime->format != cruntime->format ||
221 runtime->rate != cruntime->rate ||
222 runtime->channels != cruntime->channels;
223 if (!check)
224 return 0;
225 if (stream == SNDRV_PCM_STREAM_CAPTURE) {
226 return -EIO;
227 } else {
228 snd_pcm_stop(cable->streams[SNDRV_PCM_STREAM_CAPTURE]->
229 substream, SNDRV_PCM_STATE_DRAINING);
230 __notify:
231 runtime = cable->streams[SNDRV_PCM_STREAM_PLAYBACK]->
232 substream->runtime;
233 setup = get_setup(cable->streams[SNDRV_PCM_STREAM_PLAYBACK]);
234 card = cable->streams[SNDRV_PCM_STREAM_PLAYBACK]->loopback->card;
235 if (setup->format != runtime->format) {
236 snd_ctl_notify(card, SNDRV_CTL_EVENT_MASK_VALUE,
237 &setup->format_id);
238 setup->format = runtime->format;
239 }
240 if (setup->rate != runtime->rate) {
241 snd_ctl_notify(card, SNDRV_CTL_EVENT_MASK_VALUE,
242 &setup->rate_id);
243 setup->rate = runtime->rate;
244 }
245 if (setup->channels != runtime->channels) {
246 snd_ctl_notify(card, SNDRV_CTL_EVENT_MASK_VALUE,
247 &setup->channels_id);
248 setup->channels = runtime->channels;
249 }
250 }
251 return 0;
252 }
253
254 static void loopback_active_notify(struct loopback_pcm *dpcm)
255 {
256 snd_ctl_notify(dpcm->loopback->card,
257 SNDRV_CTL_EVENT_MASK_VALUE,
258 &get_setup(dpcm)->active_id);
259 }
260
261 static int loopback_trigger(struct snd_pcm_substream *substream, int cmd)
262 {
263 struct snd_pcm_runtime *runtime = substream->runtime;
264 struct loopback_pcm *dpcm = runtime->private_data;
265 struct loopback_cable *cable = dpcm->cable;
266 int err, stream = 1 << substream->stream;
267
268 switch (cmd) {
269 case SNDRV_PCM_TRIGGER_START:
270 err = loopback_check_format(cable, substream->stream);
271 if (err < 0)
272 return err;
273 dpcm->last_jiffies = jiffies;
274 dpcm->pcm_rate_shift = 0;
275 dpcm->last_drift = 0;
276 spin_lock(&cable->lock);
277 cable->running |= stream;
278 cable->pause &= ~stream;
279 loopback_timer_start(dpcm);
280 spin_unlock(&cable->lock);
281 if (substream->stream == SNDRV_PCM_STREAM_PLAYBACK)
282 loopback_active_notify(dpcm);
283 break;
284 case SNDRV_PCM_TRIGGER_STOP:
285 spin_lock(&cable->lock);
286 cable->running &= ~stream;
287 cable->pause &= ~stream;
288 loopback_timer_stop(dpcm);
289 spin_unlock(&cable->lock);
290 if (substream->stream == SNDRV_PCM_STREAM_PLAYBACK)
291 loopback_active_notify(dpcm);
292 break;
293 case SNDRV_PCM_TRIGGER_PAUSE_PUSH:
294 case SNDRV_PCM_TRIGGER_SUSPEND:
295 spin_lock(&cable->lock);
296 cable->pause |= stream;
297 loopback_timer_stop(dpcm);
298 spin_unlock(&cable->lock);
299 break;
300 case SNDRV_PCM_TRIGGER_PAUSE_RELEASE:
301 case SNDRV_PCM_TRIGGER_RESUME:
302 spin_lock(&cable->lock);
303 dpcm->last_jiffies = jiffies;
304 cable->pause &= ~stream;
305 loopback_timer_start(dpcm);
306 spin_unlock(&cable->lock);
307 break;
308 default:
309 return -EINVAL;
310 }
311 return 0;
312 }
313
314 static void params_change(struct snd_pcm_substream *substream)
315 {
316 struct snd_pcm_runtime *runtime = substream->runtime;
317 struct loopback_pcm *dpcm = runtime->private_data;
318 struct loopback_cable *cable = dpcm->cable;
319
320 cable->hw.formats = pcm_format_to_bits(runtime->format);
321 cable->hw.rate_min = runtime->rate;
322 cable->hw.rate_max = runtime->rate;
323 cable->hw.channels_min = runtime->channels;
324 cable->hw.channels_max = runtime->channels;
325 }
326
327 static int loopback_prepare(struct snd_pcm_substream *substream)
328 {
329 struct snd_pcm_runtime *runtime = substream->runtime;
330 struct loopback_pcm *dpcm = runtime->private_data;
331 struct loopback_cable *cable = dpcm->cable;
332 int bps, salign;
333
334 loopback_timer_stop_sync(dpcm);
335
336 salign = (snd_pcm_format_width(runtime->format) *
337 runtime->channels) / 8;
338 bps = salign * runtime->rate;
339 if (bps <= 0 || salign <= 0)
340 return -EINVAL;
341
342 dpcm->buf_pos = 0;
343 dpcm->pcm_buffer_size = frames_to_bytes(runtime, runtime->buffer_size);
344 if (substream->stream == SNDRV_PCM_STREAM_CAPTURE) {
345 /* clear capture buffer */
346 dpcm->silent_size = dpcm->pcm_buffer_size;
347 snd_pcm_format_set_silence(runtime->format, runtime->dma_area,
348 runtime->buffer_size * runtime->channels);
349 }
350
351 dpcm->irq_pos = 0;
352 dpcm->period_update_pending = 0;
353 dpcm->pcm_bps = bps;
354 dpcm->pcm_salign = salign;
355 dpcm->pcm_period_size = frames_to_bytes(runtime, runtime->period_size);
356
357 mutex_lock(&dpcm->loopback->cable_lock);
358 if (!(cable->valid & ~(1 << substream->stream)) ||
359 (get_setup(dpcm)->notify &&
360 substream->stream == SNDRV_PCM_STREAM_PLAYBACK))
361 params_change(substream);
362 cable->valid |= 1 << substream->stream;
363 mutex_unlock(&dpcm->loopback->cable_lock);
364
365 return 0;
366 }
367
368 static void clear_capture_buf(struct loopback_pcm *dpcm, unsigned int bytes)
369 {
370 struct snd_pcm_runtime *runtime = dpcm->substream->runtime;
371 char *dst = runtime->dma_area;
372 unsigned int dst_off = dpcm->buf_pos;
373
374 if (dpcm->silent_size >= dpcm->pcm_buffer_size)
375 return;
376 if (dpcm->silent_size + bytes > dpcm->pcm_buffer_size)
377 bytes = dpcm->pcm_buffer_size - dpcm->silent_size;
378
379 for (;;) {
380 unsigned int size = bytes;
381 if (dst_off + size > dpcm->pcm_buffer_size)
382 size = dpcm->pcm_buffer_size - dst_off;
383 snd_pcm_format_set_silence(runtime->format, dst + dst_off,
384 bytes_to_frames(runtime, size) *
385 runtime->channels);
386 dpcm->silent_size += size;
387 bytes -= size;
388 if (!bytes)
389 break;
390 dst_off = 0;
391 }
392 }
393
394 static void copy_play_buf(struct loopback_pcm *play,
395 struct loopback_pcm *capt,
396 unsigned int bytes)
397 {
398 struct snd_pcm_runtime *runtime = play->substream->runtime;
399 char *src = runtime->dma_area;
400 char *dst = capt->substream->runtime->dma_area;
401 unsigned int src_off = play->buf_pos;
402 unsigned int dst_off = capt->buf_pos;
403 unsigned int clear_bytes = 0;
404
405 /* check if playback is draining, trim the capture copy size
406 * when our pointer is at the end of playback ring buffer */
407 if (runtime->status->state == SNDRV_PCM_STATE_DRAINING &&
408 snd_pcm_playback_hw_avail(runtime) < runtime->buffer_size) {
409 snd_pcm_uframes_t appl_ptr, appl_ptr1, diff;
410 appl_ptr = appl_ptr1 = runtime->control->appl_ptr;
411 appl_ptr1 -= appl_ptr1 % runtime->buffer_size;
412 appl_ptr1 += play->buf_pos / play->pcm_salign;
413 if (appl_ptr < appl_ptr1)
414 appl_ptr1 -= runtime->buffer_size;
415 diff = (appl_ptr - appl_ptr1) * play->pcm_salign;
416 if (diff < bytes) {
417 clear_bytes = bytes - diff;
418 bytes = diff;
419 }
420 }
421
422 for (;;) {
423 unsigned int size = bytes;
424 if (src_off + size > play->pcm_buffer_size)
425 size = play->pcm_buffer_size - src_off;
426 if (dst_off + size > capt->pcm_buffer_size)
427 size = capt->pcm_buffer_size - dst_off;
428 memcpy(dst + dst_off, src + src_off, size);
429 capt->silent_size = 0;
430 bytes -= size;
431 if (!bytes)
432 break;
433 src_off = (src_off + size) % play->pcm_buffer_size;
434 dst_off = (dst_off + size) % capt->pcm_buffer_size;
435 }
436
437 if (clear_bytes > 0) {
438 clear_capture_buf(capt, clear_bytes);
439 capt->silent_size = 0;
440 }
441 }
442
443 static inline unsigned int bytepos_delta(struct loopback_pcm *dpcm,
444 unsigned int jiffies_delta)
445 {
446 unsigned long last_pos;
447 unsigned int delta;
448
449 last_pos = byte_pos(dpcm, dpcm->irq_pos);
450 dpcm->irq_pos += jiffies_delta * dpcm->pcm_bps;
451 delta = byte_pos(dpcm, dpcm->irq_pos) - last_pos;
452 if (delta >= dpcm->last_drift)
453 delta -= dpcm->last_drift;
454 dpcm->last_drift = 0;
455 if (dpcm->irq_pos >= dpcm->period_size_frac) {
456 dpcm->irq_pos %= dpcm->period_size_frac;
457 dpcm->period_update_pending = 1;
458 }
459 return delta;
460 }
461
462 static inline void bytepos_finish(struct loopback_pcm *dpcm,
463 unsigned int delta)
464 {
465 dpcm->buf_pos += delta;
466 dpcm->buf_pos %= dpcm->pcm_buffer_size;
467 }
468
469 /* call in cable->lock */
470 static unsigned int loopback_pos_update(struct loopback_cable *cable)
471 {
472 struct loopback_pcm *dpcm_play =
473 cable->streams[SNDRV_PCM_STREAM_PLAYBACK];
474 struct loopback_pcm *dpcm_capt =
475 cable->streams[SNDRV_PCM_STREAM_CAPTURE];
476 unsigned long delta_play = 0, delta_capt = 0;
477 unsigned int running, count1, count2;
478
479 running = cable->running ^ cable->pause;
480 if (running & (1 << SNDRV_PCM_STREAM_PLAYBACK)) {
481 delta_play = jiffies - dpcm_play->last_jiffies;
482 dpcm_play->last_jiffies += delta_play;
483 }
484
485 if (running & (1 << SNDRV_PCM_STREAM_CAPTURE)) {
486 delta_capt = jiffies - dpcm_capt->last_jiffies;
487 dpcm_capt->last_jiffies += delta_capt;
488 }
489
490 if (delta_play == 0 && delta_capt == 0)
491 goto unlock;
492
493 if (delta_play > delta_capt) {
494 count1 = bytepos_delta(dpcm_play, delta_play - delta_capt);
495 bytepos_finish(dpcm_play, count1);
496 delta_play = delta_capt;
497 } else if (delta_play < delta_capt) {
498 count1 = bytepos_delta(dpcm_capt, delta_capt - delta_play);
499 clear_capture_buf(dpcm_capt, count1);
500 bytepos_finish(dpcm_capt, count1);
501 delta_capt = delta_play;
502 }
503
504 if (delta_play == 0 && delta_capt == 0)
505 goto unlock;
506
507 /* note delta_capt == delta_play at this moment */
508 count1 = bytepos_delta(dpcm_play, delta_play);
509 count2 = bytepos_delta(dpcm_capt, delta_capt);
510 if (count1 < count2) {
511 dpcm_capt->last_drift = count2 - count1;
512 count1 = count2;
513 } else if (count1 > count2) {
514 dpcm_play->last_drift = count1 - count2;
515 }
516 copy_play_buf(dpcm_play, dpcm_capt, count1);
517 bytepos_finish(dpcm_play, count1);
518 bytepos_finish(dpcm_capt, count1);
519 unlock:
520 return running;
521 }
522
523 static void loopback_timer_function(struct timer_list *t)
524 {
525 struct loopback_pcm *dpcm = from_timer(dpcm, t, timer);
526 unsigned long flags;
527
528 spin_lock_irqsave(&dpcm->cable->lock, flags);
529 if (loopback_pos_update(dpcm->cable) & (1 << dpcm->substream->stream)) {
530 loopback_timer_start(dpcm);
531 if (dpcm->period_update_pending) {
532 dpcm->period_update_pending = 0;
533 spin_unlock_irqrestore(&dpcm->cable->lock, flags);
534 /* need to unlock before calling below */
535 snd_pcm_period_elapsed(dpcm->substream);
536 return;
537 }
538 }
539 spin_unlock_irqrestore(&dpcm->cable->lock, flags);
540 }
541
542 static snd_pcm_uframes_t loopback_pointer(struct snd_pcm_substream *substream)
543 {
544 struct snd_pcm_runtime *runtime = substream->runtime;
545 struct loopback_pcm *dpcm = runtime->private_data;
546 snd_pcm_uframes_t pos;
547
548 spin_lock(&dpcm->cable->lock);
549 loopback_pos_update(dpcm->cable);
550 pos = dpcm->buf_pos;
551 spin_unlock(&dpcm->cable->lock);
552 return bytes_to_frames(runtime, pos);
553 }
554
555 static const struct snd_pcm_hardware loopback_pcm_hardware =
556 {
557 .info = (SNDRV_PCM_INFO_INTERLEAVED | SNDRV_PCM_INFO_MMAP |
558 SNDRV_PCM_INFO_MMAP_VALID | SNDRV_PCM_INFO_PAUSE |
559 SNDRV_PCM_INFO_RESUME),
560 .formats = (SNDRV_PCM_FMTBIT_S16_LE | SNDRV_PCM_FMTBIT_S16_BE |
561 SNDRV_PCM_FMTBIT_S32_LE | SNDRV_PCM_FMTBIT_S32_BE |
562 SNDRV_PCM_FMTBIT_FLOAT_LE | SNDRV_PCM_FMTBIT_FLOAT_BE),
563 .rates = SNDRV_PCM_RATE_CONTINUOUS | SNDRV_PCM_RATE_8000_192000,
564 .rate_min = 8000,
565 .rate_max = 192000,
566 .channels_min = 1,
567 .channels_max = 32,
568 .buffer_bytes_max = 2 * 1024 * 1024,
569 .period_bytes_min = 64,
570 /* note check overflow in frac_pos() using pcm_rate_shift before
571 changing period_bytes_max value */
572 .period_bytes_max = 1024 * 1024,
573 .periods_min = 1,
574 .periods_max = 1024,
575 .fifo_size = 0,
576 };
577
578 static void loopback_runtime_free(struct snd_pcm_runtime *runtime)
579 {
580 struct loopback_pcm *dpcm = runtime->private_data;
581 kfree(dpcm);
582 }
583
584 static int loopback_hw_params(struct snd_pcm_substream *substream,
585 struct snd_pcm_hw_params *params)
586 {
587 return snd_pcm_lib_alloc_vmalloc_buffer(substream,
588 params_buffer_bytes(params));
589 }
590
591 static int loopback_hw_free(struct snd_pcm_substream *substream)
592 {
593 struct snd_pcm_runtime *runtime = substream->runtime;
594 struct loopback_pcm *dpcm = runtime->private_data;
595 struct loopback_cable *cable = dpcm->cable;
596
597 mutex_lock(&dpcm->loopback->cable_lock);
598 cable->valid &= ~(1 << substream->stream);
599 mutex_unlock(&dpcm->loopback->cable_lock);
600 return snd_pcm_lib_free_vmalloc_buffer(substream);
601 }
602
603 static unsigned int get_cable_index(struct snd_pcm_substream *substream)
604 {
605 if (!substream->pcm->device)
606 return substream->stream;
607 else
608 return !substream->stream;
609 }
610
611 static int rule_format(struct snd_pcm_hw_params *params,
612 struct snd_pcm_hw_rule *rule)
613 {
614 struct loopback_pcm *dpcm = rule->private;
615 struct loopback_cable *cable = dpcm->cable;
616 struct snd_mask m;
617
618 snd_mask_none(&m);
619 mutex_lock(&dpcm->loopback->cable_lock);
620 m.bits[0] = (u_int32_t)cable->hw.formats;
621 m.bits[1] = (u_int32_t)(cable->hw.formats >> 32);
622 mutex_unlock(&dpcm->loopback->cable_lock);
623 return snd_mask_refine(hw_param_mask(params, rule->var), &m);
624 }
625
626 static int rule_rate(struct snd_pcm_hw_params *params,
627 struct snd_pcm_hw_rule *rule)
628 {
629 struct loopback_pcm *dpcm = rule->private;
630 struct loopback_cable *cable = dpcm->cable;
631 struct snd_interval t;
632
633 mutex_lock(&dpcm->loopback->cable_lock);
634 t.min = cable->hw.rate_min;
635 t.max = cable->hw.rate_max;
636 mutex_unlock(&dpcm->loopback->cable_lock);
637 t.openmin = t.openmax = 0;
638 t.integer = 0;
639 return snd_interval_refine(hw_param_interval(params, rule->var), &t);
640 }
641
642 static int rule_channels(struct snd_pcm_hw_params *params,
643 struct snd_pcm_hw_rule *rule)
644 {
645 struct loopback_pcm *dpcm = rule->private;
646 struct loopback_cable *cable = dpcm->cable;
647 struct snd_interval t;
648
649 mutex_lock(&dpcm->loopback->cable_lock);
650 t.min = cable->hw.channels_min;
651 t.max = cable->hw.channels_max;
652 mutex_unlock(&dpcm->loopback->cable_lock);
653 t.openmin = t.openmax = 0;
654 t.integer = 0;
655 return snd_interval_refine(hw_param_interval(params, rule->var), &t);
656 }
657
658 static void free_cable(struct snd_pcm_substream *substream)
659 {
660 struct loopback *loopback = substream->private_data;
661 int dev = get_cable_index(substream);
662 struct loopback_cable *cable;
663
664 cable = loopback->cables[substream->number][dev];
665 if (!cable)
666 return;
667 if (cable->streams[!substream->stream]) {
668 /* other stream is still alive */
669 spin_lock_irq(&cable->lock);
670 cable->streams[substream->stream] = NULL;
671 spin_unlock_irq(&cable->lock);
672 } else {
673 /* free the cable */
674 loopback->cables[substream->number][dev] = NULL;
675 kfree(cable);
676 }
677 }
678
679 static int loopback_open(struct snd_pcm_substream *substream)
680 {
681 struct snd_pcm_runtime *runtime = substream->runtime;
682 struct loopback *loopback = substream->private_data;
683 struct loopback_pcm *dpcm;
684 struct loopback_cable *cable = NULL;
685 int err = 0;
686 int dev = get_cable_index(substream);
687
688 mutex_lock(&loopback->cable_lock);
689 dpcm = kzalloc(sizeof(*dpcm), GFP_KERNEL);
690 if (!dpcm) {
691 err = -ENOMEM;
692 goto unlock;
693 }
694 dpcm->loopback = loopback;
695 dpcm->substream = substream;
696 timer_setup(&dpcm->timer, loopback_timer_function, 0);
697
698 cable = loopback->cables[substream->number][dev];
699 if (!cable) {
700 cable = kzalloc(sizeof(*cable), GFP_KERNEL);
701 if (!cable) {
702 err = -ENOMEM;
703 goto unlock;
704 }
705 spin_lock_init(&cable->lock);
706 cable->hw = loopback_pcm_hardware;
707 loopback->cables[substream->number][dev] = cable;
708 }
709 dpcm->cable = cable;
710
711 snd_pcm_hw_constraint_integer(runtime, SNDRV_PCM_HW_PARAM_PERIODS);
712
713 /* use dynamic rules based on actual runtime->hw values */
714 /* note that the default rules created in the PCM midlevel code */
715 /* are cached -> they do not reflect the actual state */
716 err = snd_pcm_hw_rule_add(runtime, 0,
717 SNDRV_PCM_HW_PARAM_FORMAT,
718 rule_format, dpcm,
719 SNDRV_PCM_HW_PARAM_FORMAT, -1);
720 if (err < 0)
721 goto unlock;
722 err = snd_pcm_hw_rule_add(runtime, 0,
723 SNDRV_PCM_HW_PARAM_RATE,
724 rule_rate, dpcm,
725 SNDRV_PCM_HW_PARAM_RATE, -1);
726 if (err < 0)
727 goto unlock;
728 err = snd_pcm_hw_rule_add(runtime, 0,
729 SNDRV_PCM_HW_PARAM_CHANNELS,
730 rule_channels, dpcm,
731 SNDRV_PCM_HW_PARAM_CHANNELS, -1);
732 if (err < 0)
733 goto unlock;
734
735 runtime->private_data = dpcm;
736 runtime->private_free = loopback_runtime_free;
737 if (get_notify(dpcm))
738 runtime->hw = loopback_pcm_hardware;
739 else
740 runtime->hw = cable->hw;
741
742 spin_lock_irq(&cable->lock);
743 cable->streams[substream->stream] = dpcm;
744 spin_unlock_irq(&cable->lock);
745
746 unlock:
747 if (err < 0) {
748 free_cable(substream);
749 kfree(dpcm);
750 }
751 mutex_unlock(&loopback->cable_lock);
752 return err;
753 }
754
755 static int loopback_close(struct snd_pcm_substream *substream)
756 {
757 struct loopback *loopback = substream->private_data;
758 struct loopback_pcm *dpcm = substream->runtime->private_data;
759
760 loopback_timer_stop_sync(dpcm);
761 mutex_lock(&loopback->cable_lock);
762 free_cable(substream);
763 mutex_unlock(&loopback->cable_lock);
764 return 0;
765 }
766
767 static const struct snd_pcm_ops loopback_playback_ops = {
768 .open = loopback_open,
769 .close = loopback_close,
770 .ioctl = snd_pcm_lib_ioctl,
771 .hw_params = loopback_hw_params,
772 .hw_free = loopback_hw_free,
773 .prepare = loopback_prepare,
774 .trigger = loopback_trigger,
775 .pointer = loopback_pointer,
776 .page = snd_pcm_lib_get_vmalloc_page,
777 .mmap = snd_pcm_lib_mmap_vmalloc,
778 };
779
780 static const struct snd_pcm_ops loopback_capture_ops = {
781 .open = loopback_open,
782 .close = loopback_close,
783 .ioctl = snd_pcm_lib_ioctl,
784 .hw_params = loopback_hw_params,
785 .hw_free = loopback_hw_free,
786 .prepare = loopback_prepare,
787 .trigger = loopback_trigger,
788 .pointer = loopback_pointer,
789 .page = snd_pcm_lib_get_vmalloc_page,
790 .mmap = snd_pcm_lib_mmap_vmalloc,
791 };
792
793 static int loopback_pcm_new(struct loopback *loopback,
794 int device, int substreams)
795 {
796 struct snd_pcm *pcm;
797 int err;
798
799 err = snd_pcm_new(loopback->card, "Loopback PCM", device,
800 substreams, substreams, &pcm);
801 if (err < 0)
802 return err;
803 snd_pcm_set_ops(pcm, SNDRV_PCM_STREAM_PLAYBACK, &loopback_playback_ops);
804 snd_pcm_set_ops(pcm, SNDRV_PCM_STREAM_CAPTURE, &loopback_capture_ops);
805
806 pcm->private_data = loopback;
807 pcm->info_flags = 0;
808 strcpy(pcm->name, "Loopback PCM");
809
810 loopback->pcm[device] = pcm;
811 return 0;
812 }
813
814 static int loopback_rate_shift_info(struct snd_kcontrol *kcontrol,
815 struct snd_ctl_elem_info *uinfo)
816 {
817 uinfo->type = SNDRV_CTL_ELEM_TYPE_INTEGER;
818 uinfo->count = 1;
819 uinfo->value.integer.min = 80000;
820 uinfo->value.integer.max = 120000;
821 uinfo->value.integer.step = 1;
822 return 0;
823 }
824
825 static int loopback_rate_shift_get(struct snd_kcontrol *kcontrol,
826 struct snd_ctl_elem_value *ucontrol)
827 {
828 struct loopback *loopback = snd_kcontrol_chip(kcontrol);
829
830 ucontrol->value.integer.value[0] =
831 loopback->setup[kcontrol->id.subdevice]
832 [kcontrol->id.device].rate_shift;
833 return 0;
834 }
835
836 static int loopback_rate_shift_put(struct snd_kcontrol *kcontrol,
837 struct snd_ctl_elem_value *ucontrol)
838 {
839 struct loopback *loopback = snd_kcontrol_chip(kcontrol);
840 unsigned int val;
841 int change = 0;
842
843 val = ucontrol->value.integer.value[0];
844 if (val < 80000)
845 val = 80000;
846 if (val > 120000)
847 val = 120000;
848 mutex_lock(&loopback->cable_lock);
849 if (val != loopback->setup[kcontrol->id.subdevice]
850 [kcontrol->id.device].rate_shift) {
851 loopback->setup[kcontrol->id.subdevice]
852 [kcontrol->id.device].rate_shift = val;
853 change = 1;
854 }
855 mutex_unlock(&loopback->cable_lock);
856 return change;
857 }
858
859 static int loopback_notify_get(struct snd_kcontrol *kcontrol,
860 struct snd_ctl_elem_value *ucontrol)
861 {
862 struct loopback *loopback = snd_kcontrol_chip(kcontrol);
863
864 ucontrol->value.integer.value[0] =
865 loopback->setup[kcontrol->id.subdevice]
866 [kcontrol->id.device].notify;
867 return 0;
868 }
869
870 static int loopback_notify_put(struct snd_kcontrol *kcontrol,
871 struct snd_ctl_elem_value *ucontrol)
872 {
873 struct loopback *loopback = snd_kcontrol_chip(kcontrol);
874 unsigned int val;
875 int change = 0;
876
877 val = ucontrol->value.integer.value[0] ? 1 : 0;
878 if (val != loopback->setup[kcontrol->id.subdevice]
879 [kcontrol->id.device].notify) {
880 loopback->setup[kcontrol->id.subdevice]
881 [kcontrol->id.device].notify = val;
882 change = 1;
883 }
884 return change;
885 }
886
887 static int loopback_active_get(struct snd_kcontrol *kcontrol,
888 struct snd_ctl_elem_value *ucontrol)
889 {
890 struct loopback *loopback = snd_kcontrol_chip(kcontrol);
891 struct loopback_cable *cable = loopback->cables
892 [kcontrol->id.subdevice][kcontrol->id.device ^ 1];
893 unsigned int val = 0;
894
895 if (cable != NULL)
896 val = (cable->running & (1 << SNDRV_PCM_STREAM_PLAYBACK)) ?
897 1 : 0;
898 ucontrol->value.integer.value[0] = val;
899 return 0;
900 }
901
902 static int loopback_format_info(struct snd_kcontrol *kcontrol,
903 struct snd_ctl_elem_info *uinfo)
904 {
905 uinfo->type = SNDRV_CTL_ELEM_TYPE_INTEGER;
906 uinfo->count = 1;
907 uinfo->value.integer.min = 0;
908 uinfo->value.integer.max = SNDRV_PCM_FORMAT_LAST;
909 uinfo->value.integer.step = 1;
910 return 0;
911 }
912
913 static int loopback_format_get(struct snd_kcontrol *kcontrol,
914 struct snd_ctl_elem_value *ucontrol)
915 {
916 struct loopback *loopback = snd_kcontrol_chip(kcontrol);
917
918 ucontrol->value.integer.value[0] =
919 loopback->setup[kcontrol->id.subdevice]
920 [kcontrol->id.device].format;
921 return 0;
922 }
923
924 static int loopback_rate_info(struct snd_kcontrol *kcontrol,
925 struct snd_ctl_elem_info *uinfo)
926 {
927 uinfo->type = SNDRV_CTL_ELEM_TYPE_INTEGER;
928 uinfo->count = 1;
929 uinfo->value.integer.min = 0;
930 uinfo->value.integer.max = 192000;
931 uinfo->value.integer.step = 1;
932 return 0;
933 }
934
935 static int loopback_rate_get(struct snd_kcontrol *kcontrol,
936 struct snd_ctl_elem_value *ucontrol)
937 {
938 struct loopback *loopback = snd_kcontrol_chip(kcontrol);
939
940 ucontrol->value.integer.value[0] =
941 loopback->setup[kcontrol->id.subdevice]
942 [kcontrol->id.device].rate;
943 return 0;
944 }
945
946 static int loopback_channels_info(struct snd_kcontrol *kcontrol,
947 struct snd_ctl_elem_info *uinfo)
948 {
949 uinfo->type = SNDRV_CTL_ELEM_TYPE_INTEGER;
950 uinfo->count = 1;
951 uinfo->value.integer.min = 1;
952 uinfo->value.integer.max = 1024;
953 uinfo->value.integer.step = 1;
954 return 0;
955 }
956
957 static int loopback_channels_get(struct snd_kcontrol *kcontrol,
958 struct snd_ctl_elem_value *ucontrol)
959 {
960 struct loopback *loopback = snd_kcontrol_chip(kcontrol);
961
962 ucontrol->value.integer.value[0] =
963 loopback->setup[kcontrol->id.subdevice]
964 [kcontrol->id.device].channels;
965 return 0;
966 }
967
968 static struct snd_kcontrol_new loopback_controls[] = {
969 {
970 .iface = SNDRV_CTL_ELEM_IFACE_PCM,
971 .name = "PCM Rate Shift 100000",
972 .info = loopback_rate_shift_info,
973 .get = loopback_rate_shift_get,
974 .put = loopback_rate_shift_put,
975 },
976 {
977 .iface = SNDRV_CTL_ELEM_IFACE_PCM,
978 .name = "PCM Notify",
979 .info = snd_ctl_boolean_mono_info,
980 .get = loopback_notify_get,
981 .put = loopback_notify_put,
982 },
983 #define ACTIVE_IDX 2
984 {
985 .access = SNDRV_CTL_ELEM_ACCESS_READ,
986 .iface = SNDRV_CTL_ELEM_IFACE_PCM,
987 .name = "PCM Slave Active",
988 .info = snd_ctl_boolean_mono_info,
989 .get = loopback_active_get,
990 },
991 #define FORMAT_IDX 3
992 {
993 .access = SNDRV_CTL_ELEM_ACCESS_READ,
994 .iface = SNDRV_CTL_ELEM_IFACE_PCM,
995 .name = "PCM Slave Format",
996 .info = loopback_format_info,
997 .get = loopback_format_get
998 },
999 #define RATE_IDX 4
1000 {
1001 .access = SNDRV_CTL_ELEM_ACCESS_READ,
1002 .iface = SNDRV_CTL_ELEM_IFACE_PCM,
1003 .name = "PCM Slave Rate",
1004 .info = loopback_rate_info,
1005 .get = loopback_rate_get
1006 },
1007 #define CHANNELS_IDX 5
1008 {
1009 .access = SNDRV_CTL_ELEM_ACCESS_READ,
1010 .iface = SNDRV_CTL_ELEM_IFACE_PCM,
1011 .name = "PCM Slave Channels",
1012 .info = loopback_channels_info,
1013 .get = loopback_channels_get
1014 }
1015 };
1016
1017 static int loopback_mixer_new(struct loopback *loopback, int notify)
1018 {
1019 struct snd_card *card = loopback->card;
1020 struct snd_pcm *pcm;
1021 struct snd_kcontrol *kctl;
1022 struct loopback_setup *setup;
1023 int err, dev, substr, substr_count, idx;
1024
1025 strcpy(card->mixername, "Loopback Mixer");
1026 for (dev = 0; dev < 2; dev++) {
1027 pcm = loopback->pcm[dev];
1028 substr_count =
1029 pcm->streams[SNDRV_PCM_STREAM_CAPTURE].substream_count;
1030 for (substr = 0; substr < substr_count; substr++) {
1031 setup = &loopback->setup[substr][dev];
1032 setup->notify = notify;
1033 setup->rate_shift = NO_PITCH;
1034 setup->format = SNDRV_PCM_FORMAT_S16_LE;
1035 setup->rate = 48000;
1036 setup->channels = 2;
1037 for (idx = 0; idx < ARRAY_SIZE(loopback_controls);
1038 idx++) {
1039 kctl = snd_ctl_new1(&loopback_controls[idx],
1040 loopback);
1041 if (!kctl)
1042 return -ENOMEM;
1043 kctl->id.device = dev;
1044 kctl->id.subdevice = substr;
1045 switch (idx) {
1046 case ACTIVE_IDX:
1047 setup->active_id = kctl->id;
1048 break;
1049 case FORMAT_IDX:
1050 setup->format_id = kctl->id;
1051 break;
1052 case RATE_IDX:
1053 setup->rate_id = kctl->id;
1054 break;
1055 case CHANNELS_IDX:
1056 setup->channels_id = kctl->id;
1057 break;
1058 default:
1059 break;
1060 }
1061 err = snd_ctl_add(card, kctl);
1062 if (err < 0)
1063 return err;
1064 }
1065 }
1066 }
1067 return 0;
1068 }
1069
1070 static void print_dpcm_info(struct snd_info_buffer *buffer,
1071 struct loopback_pcm *dpcm,
1072 const char *id)
1073 {
1074 snd_iprintf(buffer, " %s\n", id);
1075 if (dpcm == NULL) {
1076 snd_iprintf(buffer, " inactive\n");
1077 return;
1078 }
1079 snd_iprintf(buffer, " buffer_size:\t%u\n", dpcm->pcm_buffer_size);
1080 snd_iprintf(buffer, " buffer_pos:\t\t%u\n", dpcm->buf_pos);
1081 snd_iprintf(buffer, " silent_size:\t%u\n", dpcm->silent_size);
1082 snd_iprintf(buffer, " period_size:\t%u\n", dpcm->pcm_period_size);
1083 snd_iprintf(buffer, " bytes_per_sec:\t%u\n", dpcm->pcm_bps);
1084 snd_iprintf(buffer, " sample_align:\t%u\n", dpcm->pcm_salign);
1085 snd_iprintf(buffer, " rate_shift:\t\t%u\n", dpcm->pcm_rate_shift);
1086 snd_iprintf(buffer, " update_pending:\t%u\n",
1087 dpcm->period_update_pending);
1088 snd_iprintf(buffer, " irq_pos:\t\t%u\n", dpcm->irq_pos);
1089 snd_iprintf(buffer, " period_frac:\t%u\n", dpcm->period_size_frac);
1090 snd_iprintf(buffer, " last_jiffies:\t%lu (%lu)\n",
1091 dpcm->last_jiffies, jiffies);
1092 snd_iprintf(buffer, " timer_expires:\t%lu\n", dpcm->timer.expires);
1093 }
1094
1095 static void print_substream_info(struct snd_info_buffer *buffer,
1096 struct loopback *loopback,
1097 int sub,
1098 int num)
1099 {
1100 struct loopback_cable *cable = loopback->cables[sub][num];
1101
1102 snd_iprintf(buffer, "Cable %i substream %i:\n", num, sub);
1103 if (cable == NULL) {
1104 snd_iprintf(buffer, " inactive\n");
1105 return;
1106 }
1107 snd_iprintf(buffer, " valid: %u\n", cable->valid);
1108 snd_iprintf(buffer, " running: %u\n", cable->running);
1109 snd_iprintf(buffer, " pause: %u\n", cable->pause);
1110 print_dpcm_info(buffer, cable->streams[0], "Playback");
1111 print_dpcm_info(buffer, cable->streams[1], "Capture");
1112 }
1113
1114 static void print_cable_info(struct snd_info_entry *entry,
1115 struct snd_info_buffer *buffer)
1116 {
1117 struct loopback *loopback = entry->private_data;
1118 int sub, num;
1119
1120 mutex_lock(&loopback->cable_lock);
1121 num = entry->name[strlen(entry->name)-1];
1122 num = num == '0' ? 0 : 1;
1123 for (sub = 0; sub < MAX_PCM_SUBSTREAMS; sub++)
1124 print_substream_info(buffer, loopback, sub, num);
1125 mutex_unlock(&loopback->cable_lock);
1126 }
1127
1128 static int loopback_proc_new(struct loopback *loopback, int cidx)
1129 {
1130 char name[32];
1131 struct snd_info_entry *entry;
1132 int err;
1133
1134 snprintf(name, sizeof(name), "cable#%d", cidx);
1135 err = snd_card_proc_new(loopback->card, name, &entry);
1136 if (err < 0)
1137 return err;
1138
1139 snd_info_set_text_ops(entry, loopback, print_cable_info);
1140 return 0;
1141 }
1142
1143 static int loopback_probe(struct platform_device *devptr)
1144 {
1145 struct snd_card *card;
1146 struct loopback *loopback;
1147 int dev = devptr->id;
1148 int err;
1149
1150 err = snd_card_new(&devptr->dev, index[dev], id[dev], THIS_MODULE,
1151 sizeof(struct loopback), &card);
1152 if (err < 0)
1153 return err;
1154 loopback = card->private_data;
1155
1156 if (pcm_substreams[dev] < 1)
1157 pcm_substreams[dev] = 1;
1158 if (pcm_substreams[dev] > MAX_PCM_SUBSTREAMS)
1159 pcm_substreams[dev] = MAX_PCM_SUBSTREAMS;
1160
1161 loopback->card = card;
1162 mutex_init(&loopback->cable_lock);
1163
1164 err = loopback_pcm_new(loopback, 0, pcm_substreams[dev]);
1165 if (err < 0)
1166 goto __nodev;
1167 err = loopback_pcm_new(loopback, 1, pcm_substreams[dev]);
1168 if (err < 0)
1169 goto __nodev;
1170 err = loopback_mixer_new(loopback, pcm_notify[dev] ? 1 : 0);
1171 if (err < 0)
1172 goto __nodev;
1173 loopback_proc_new(loopback, 0);
1174 loopback_proc_new(loopback, 1);
1175 strcpy(card->driver, "Loopback");
1176 strcpy(card->shortname, "Loopback");
1177 sprintf(card->longname, "Loopback %i", dev + 1);
1178 err = snd_card_register(card);
1179 if (!err) {
1180 platform_set_drvdata(devptr, card);
1181 return 0;
1182 }
1183 __nodev:
1184 snd_card_free(card);
1185 return err;
1186 }
1187
1188 static int loopback_remove(struct platform_device *devptr)
1189 {
1190 snd_card_free(platform_get_drvdata(devptr));
1191 return 0;
1192 }
1193
1194 #ifdef CONFIG_PM_SLEEP
1195 static int loopback_suspend(struct device *pdev)
1196 {
1197 struct snd_card *card = dev_get_drvdata(pdev);
1198 struct loopback *loopback = card->private_data;
1199
1200 snd_power_change_state(card, SNDRV_CTL_POWER_D3hot);
1201
1202 snd_pcm_suspend_all(loopback->pcm[0]);
1203 snd_pcm_suspend_all(loopback->pcm[1]);
1204 return 0;
1205 }
1206
1207 static int loopback_resume(struct device *pdev)
1208 {
1209 struct snd_card *card = dev_get_drvdata(pdev);
1210
1211 snd_power_change_state(card, SNDRV_CTL_POWER_D0);
1212 return 0;
1213 }
1214
1215 static SIMPLE_DEV_PM_OPS(loopback_pm, loopback_suspend, loopback_resume);
1216 #define LOOPBACK_PM_OPS &loopback_pm
1217 #else
1218 #define LOOPBACK_PM_OPS NULL
1219 #endif
1220
1221 #define SND_LOOPBACK_DRIVER "snd_aloop"
1222
1223 static struct platform_driver loopback_driver = {
1224 .probe = loopback_probe,
1225 .remove = loopback_remove,
1226 .driver = {
1227 .name = SND_LOOPBACK_DRIVER,
1228 .pm = LOOPBACK_PM_OPS,
1229 },
1230 };
1231
1232 static void loopback_unregister_all(void)
1233 {
1234 int i;
1235
1236 for (i = 0; i < ARRAY_SIZE(devices); ++i)
1237 platform_device_unregister(devices[i]);
1238 platform_driver_unregister(&loopback_driver);
1239 }
1240
1241 static int __init alsa_card_loopback_init(void)
1242 {
1243 int i, err, cards;
1244
1245 err = platform_driver_register(&loopback_driver);
1246 if (err < 0)
1247 return err;
1248
1249
1250 cards = 0;
1251 for (i = 0; i < SNDRV_CARDS; i++) {
1252 struct platform_device *device;
1253 if (!enable[i])
1254 continue;
1255 device = platform_device_register_simple(SND_LOOPBACK_DRIVER,
1256 i, NULL, 0);
1257 if (IS_ERR(device))
1258 continue;
1259 if (!platform_get_drvdata(device)) {
1260 platform_device_unregister(device);
1261 continue;
1262 }
1263 devices[i] = device;
1264 cards++;
1265 }
1266 if (!cards) {
1267 #ifdef MODULE
1268 printk(KERN_ERR "aloop: No loopback enabled\n");
1269 #endif
1270 loopback_unregister_all();
1271 return -ENODEV;
1272 }
1273 return 0;
1274 }
1275
1276 static void __exit alsa_card_loopback_exit(void)
1277 {
1278 loopback_unregister_all();
1279 }
1280
1281 module_init(alsa_card_loopback_init)
1282 module_exit(alsa_card_loopback_exit)
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