This source file includes following definitions.
- byte_pos
- frac_pos
- get_setup
- get_notify
- get_rate_shift
- loopback_timer_start
- loopback_timer_stop
- loopback_timer_stop_sync
- loopback_check_format
- loopback_active_notify
- loopback_trigger
- params_change
- loopback_prepare
- clear_capture_buf
- copy_play_buf
- bytepos_delta
- bytepos_finish
- loopback_pos_update
- loopback_timer_function
- loopback_pointer
- loopback_runtime_free
- loopback_hw_params
- loopback_hw_free
- get_cable_index
- rule_format
- rule_rate
- rule_channels
- free_cable
- loopback_open
- loopback_close
- loopback_pcm_new
- loopback_rate_shift_info
- loopback_rate_shift_get
- loopback_rate_shift_put
- loopback_notify_get
- loopback_notify_put
- loopback_active_get
- loopback_format_info
- loopback_format_get
- loopback_rate_info
- loopback_rate_get
- loopback_channels_info
- loopback_channels_get
- loopback_mixer_new
- print_dpcm_info
- print_substream_info
- print_cable_info
- loopback_proc_new
- loopback_probe
- loopback_remove
- loopback_suspend
- loopback_resume
- loopback_unregister_all
- alsa_card_loopback_init
- alsa_card_loopback_exit
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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
32 MODULE_AUTHOR("Jaroslav Kysela <perex@perex.cz>");
33 MODULE_DESCRIPTION("A loopback soundcard");
34 MODULE_LICENSE("GPL");
35 MODULE_SUPPORTED_DEVICE("{{ALSA,Loopback soundcard}}");
36
37 #define MAX_PCM_SUBSTREAMS 8
38
39 static int index[SNDRV_CARDS] = SNDRV_DEFAULT_IDX;
40 static char *id[SNDRV_CARDS] = SNDRV_DEFAULT_STR;
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
45 module_param_array(index, int, NULL, 0444);
46 MODULE_PARM_DESC(index, "Index value for loopback soundcard.");
47 module_param_array(id, charp, NULL, 0444);
48 MODULE_PARM_DESC(id, "ID string for loopback soundcard.");
49 module_param_array(enable, bool, NULL, 0444);
50 MODULE_PARM_DESC(enable, "Enable this loopback soundcard.");
51 module_param_array(pcm_substreams, int, NULL, 0444);
52 MODULE_PARM_DESC(pcm_substreams, "PCM substreams # (1-8) for loopback driver.");
53 module_param_array(pcm_notify, int, NULL, 0444);
54 MODULE_PARM_DESC(pcm_notify, "Break capture when PCM format/rate/channels changes.");
55
56 #define NO_PITCH 100000
57
58 struct loopback_pcm;
59
60 struct loopback_cable {
61 spinlock_t lock;
62 struct loopback_pcm *streams[2];
63 struct snd_pcm_hardware hw;
64
65 unsigned int valid;
66 unsigned int running;
67 unsigned int pause;
68 };
69
70 struct loopback_setup {
71 unsigned int notify: 1;
72 unsigned int rate_shift;
73 unsigned int format;
74 unsigned int rate;
75 unsigned int channels;
76 struct snd_ctl_elem_id active_id;
77 struct snd_ctl_elem_id format_id;
78 struct snd_ctl_elem_id rate_id;
79 struct snd_ctl_elem_id channels_id;
80 };
81
82 struct loopback {
83 struct snd_card *card;
84 struct mutex cable_lock;
85 struct loopback_cable *cables[MAX_PCM_SUBSTREAMS][2];
86 struct snd_pcm *pcm[2];
87 struct loopback_setup setup[MAX_PCM_SUBSTREAMS][2];
88 };
89
90 struct loopback_pcm {
91 struct loopback *loopback;
92 struct snd_pcm_substream *substream;
93 struct loopback_cable *cable;
94 unsigned int pcm_buffer_size;
95 unsigned int buf_pos;
96 unsigned int silent_size;
97
98 unsigned int pcm_period_size;
99 unsigned int pcm_bps;
100 unsigned int pcm_salign;
101 unsigned int pcm_rate_shift;
102
103 unsigned int period_update_pending :1;
104
105 unsigned int irq_pos;
106 unsigned int period_size_frac;
107 unsigned int last_drift;
108 unsigned long last_jiffies;
109 struct timer_list timer;
110 };
111
112 static struct platform_device *devices[SNDRV_CARDS];
113
114 static inline unsigned int byte_pos(struct loopback_pcm *dpcm, unsigned int x)
115 {
116 if (dpcm->pcm_rate_shift == NO_PITCH) {
117 x /= HZ;
118 } else {
119 x = div_u64(NO_PITCH * (unsigned long long)x,
120 HZ * (unsigned long long)dpcm->pcm_rate_shift);
121 }
122 return x - (x % dpcm->pcm_salign);
123 }
124
125 static inline unsigned int frac_pos(struct loopback_pcm *dpcm, unsigned int x)
126 {
127 if (dpcm->pcm_rate_shift == NO_PITCH) {
128 return x * HZ;
129 } else {
130 x = div_u64(dpcm->pcm_rate_shift * (unsigned long long)x * HZ,
131 NO_PITCH);
132 }
133 return x;
134 }
135
136 static inline struct loopback_setup *get_setup(struct loopback_pcm *dpcm)
137 {
138 int device = dpcm->substream->pstr->pcm->device;
139
140 if (dpcm->substream->stream == SNDRV_PCM_STREAM_PLAYBACK)
141 device ^= 1;
142 return &dpcm->loopback->setup[dpcm->substream->number][device];
143 }
144
145 static inline unsigned int get_notify(struct loopback_pcm *dpcm)
146 {
147 return get_setup(dpcm)->notify;
148 }
149
150 static inline unsigned int get_rate_shift(struct loopback_pcm *dpcm)
151 {
152 return get_setup(dpcm)->rate_shift;
153 }
154
155
156 static void loopback_timer_start(struct loopback_pcm *dpcm)
157 {
158 unsigned long tick;
159 unsigned int rate_shift = get_rate_shift(dpcm);
160
161 if (rate_shift != dpcm->pcm_rate_shift) {
162 dpcm->pcm_rate_shift = rate_shift;
163 dpcm->period_size_frac = frac_pos(dpcm, dpcm->pcm_period_size);
164 }
165 if (dpcm->period_size_frac <= dpcm->irq_pos) {
166 dpcm->irq_pos %= dpcm->period_size_frac;
167 dpcm->period_update_pending = 1;
168 }
169 tick = dpcm->period_size_frac - dpcm->irq_pos;
170 tick = (tick + dpcm->pcm_bps - 1) / dpcm->pcm_bps;
171 mod_timer(&dpcm->timer, jiffies + tick);
172 }
173
174
175 static inline void loopback_timer_stop(struct loopback_pcm *dpcm)
176 {
177 del_timer(&dpcm->timer);
178 dpcm->timer.expires = 0;
179 }
180
181 static inline void loopback_timer_stop_sync(struct loopback_pcm *dpcm)
182 {
183 del_timer_sync(&dpcm->timer);
184 }
185
186 #define CABLE_VALID_PLAYBACK (1 << SNDRV_PCM_STREAM_PLAYBACK)
187 #define CABLE_VALID_CAPTURE (1 << SNDRV_PCM_STREAM_CAPTURE)
188 #define CABLE_VALID_BOTH (CABLE_VALID_PLAYBACK|CABLE_VALID_CAPTURE)
189
190 static int loopback_check_format(struct loopback_cable *cable, int stream)
191 {
192 struct snd_pcm_runtime *runtime, *cruntime;
193 struct loopback_setup *setup;
194 struct snd_card *card;
195 int check;
196
197 if (cable->valid != CABLE_VALID_BOTH) {
198 if (stream == SNDRV_PCM_STREAM_PLAYBACK)
199 goto __notify;
200 return 0;
201 }
202 runtime = cable->streams[SNDRV_PCM_STREAM_PLAYBACK]->
203 substream->runtime;
204 cruntime = cable->streams[SNDRV_PCM_STREAM_CAPTURE]->
205 substream->runtime;
206 check = runtime->format != cruntime->format ||
207 runtime->rate != cruntime->rate ||
208 runtime->channels != cruntime->channels;
209 if (!check)
210 return 0;
211 if (stream == SNDRV_PCM_STREAM_CAPTURE) {
212 return -EIO;
213 } else {
214 snd_pcm_stop(cable->streams[SNDRV_PCM_STREAM_CAPTURE]->
215 substream, SNDRV_PCM_STATE_DRAINING);
216 __notify:
217 runtime = cable->streams[SNDRV_PCM_STREAM_PLAYBACK]->
218 substream->runtime;
219 setup = get_setup(cable->streams[SNDRV_PCM_STREAM_PLAYBACK]);
220 card = cable->streams[SNDRV_PCM_STREAM_PLAYBACK]->loopback->card;
221 if (setup->format != runtime->format) {
222 snd_ctl_notify(card, SNDRV_CTL_EVENT_MASK_VALUE,
223 &setup->format_id);
224 setup->format = runtime->format;
225 }
226 if (setup->rate != runtime->rate) {
227 snd_ctl_notify(card, SNDRV_CTL_EVENT_MASK_VALUE,
228 &setup->rate_id);
229 setup->rate = runtime->rate;
230 }
231 if (setup->channels != runtime->channels) {
232 snd_ctl_notify(card, SNDRV_CTL_EVENT_MASK_VALUE,
233 &setup->channels_id);
234 setup->channels = runtime->channels;
235 }
236 }
237 return 0;
238 }
239
240 static void loopback_active_notify(struct loopback_pcm *dpcm)
241 {
242 snd_ctl_notify(dpcm->loopback->card,
243 SNDRV_CTL_EVENT_MASK_VALUE,
244 &get_setup(dpcm)->active_id);
245 }
246
247 static int loopback_trigger(struct snd_pcm_substream *substream, int cmd)
248 {
249 struct snd_pcm_runtime *runtime = substream->runtime;
250 struct loopback_pcm *dpcm = runtime->private_data;
251 struct loopback_cable *cable = dpcm->cable;
252 int err, stream = 1 << substream->stream;
253
254 switch (cmd) {
255 case SNDRV_PCM_TRIGGER_START:
256 err = loopback_check_format(cable, substream->stream);
257 if (err < 0)
258 return err;
259 dpcm->last_jiffies = jiffies;
260 dpcm->pcm_rate_shift = 0;
261 dpcm->last_drift = 0;
262 spin_lock(&cable->lock);
263 cable->running |= stream;
264 cable->pause &= ~stream;
265 loopback_timer_start(dpcm);
266 spin_unlock(&cable->lock);
267 if (substream->stream == SNDRV_PCM_STREAM_PLAYBACK)
268 loopback_active_notify(dpcm);
269 break;
270 case SNDRV_PCM_TRIGGER_STOP:
271 spin_lock(&cable->lock);
272 cable->running &= ~stream;
273 cable->pause &= ~stream;
274 loopback_timer_stop(dpcm);
275 spin_unlock(&cable->lock);
276 if (substream->stream == SNDRV_PCM_STREAM_PLAYBACK)
277 loopback_active_notify(dpcm);
278 break;
279 case SNDRV_PCM_TRIGGER_PAUSE_PUSH:
280 case SNDRV_PCM_TRIGGER_SUSPEND:
281 spin_lock(&cable->lock);
282 cable->pause |= stream;
283 loopback_timer_stop(dpcm);
284 spin_unlock(&cable->lock);
285 if (substream->stream == SNDRV_PCM_STREAM_PLAYBACK)
286 loopback_active_notify(dpcm);
287 break;
288 case SNDRV_PCM_TRIGGER_PAUSE_RELEASE:
289 case SNDRV_PCM_TRIGGER_RESUME:
290 spin_lock(&cable->lock);
291 dpcm->last_jiffies = jiffies;
292 cable->pause &= ~stream;
293 loopback_timer_start(dpcm);
294 spin_unlock(&cable->lock);
295 if (substream->stream == SNDRV_PCM_STREAM_PLAYBACK)
296 loopback_active_notify(dpcm);
297 break;
298 default:
299 return -EINVAL;
300 }
301 return 0;
302 }
303
304 static void params_change(struct snd_pcm_substream *substream)
305 {
306 struct snd_pcm_runtime *runtime = substream->runtime;
307 struct loopback_pcm *dpcm = runtime->private_data;
308 struct loopback_cable *cable = dpcm->cable;
309
310 cable->hw.formats = pcm_format_to_bits(runtime->format);
311 cable->hw.rate_min = runtime->rate;
312 cable->hw.rate_max = runtime->rate;
313 cable->hw.channels_min = runtime->channels;
314 cable->hw.channels_max = runtime->channels;
315 }
316
317 static int loopback_prepare(struct snd_pcm_substream *substream)
318 {
319 struct snd_pcm_runtime *runtime = substream->runtime;
320 struct loopback_pcm *dpcm = runtime->private_data;
321 struct loopback_cable *cable = dpcm->cable;
322 int bps, salign;
323
324 loopback_timer_stop_sync(dpcm);
325
326 salign = (snd_pcm_format_physical_width(runtime->format) *
327 runtime->channels) / 8;
328 bps = salign * runtime->rate;
329 if (bps <= 0 || salign <= 0)
330 return -EINVAL;
331
332 dpcm->buf_pos = 0;
333 dpcm->pcm_buffer_size = frames_to_bytes(runtime, runtime->buffer_size);
334 if (substream->stream == SNDRV_PCM_STREAM_CAPTURE) {
335
336 dpcm->silent_size = dpcm->pcm_buffer_size;
337 snd_pcm_format_set_silence(runtime->format, runtime->dma_area,
338 runtime->buffer_size * runtime->channels);
339 }
340
341 dpcm->irq_pos = 0;
342 dpcm->period_update_pending = 0;
343 dpcm->pcm_bps = bps;
344 dpcm->pcm_salign = salign;
345 dpcm->pcm_period_size = frames_to_bytes(runtime, runtime->period_size);
346
347 mutex_lock(&dpcm->loopback->cable_lock);
348 if (!(cable->valid & ~(1 << substream->stream)) ||
349 (get_setup(dpcm)->notify &&
350 substream->stream == SNDRV_PCM_STREAM_PLAYBACK))
351 params_change(substream);
352 cable->valid |= 1 << substream->stream;
353 mutex_unlock(&dpcm->loopback->cable_lock);
354
355 return 0;
356 }
357
358 static void clear_capture_buf(struct loopback_pcm *dpcm, unsigned int bytes)
359 {
360 struct snd_pcm_runtime *runtime = dpcm->substream->runtime;
361 char *dst = runtime->dma_area;
362 unsigned int dst_off = dpcm->buf_pos;
363
364 if (dpcm->silent_size >= dpcm->pcm_buffer_size)
365 return;
366 if (dpcm->silent_size + bytes > dpcm->pcm_buffer_size)
367 bytes = dpcm->pcm_buffer_size - dpcm->silent_size;
368
369 for (;;) {
370 unsigned int size = bytes;
371 if (dst_off + size > dpcm->pcm_buffer_size)
372 size = dpcm->pcm_buffer_size - dst_off;
373 snd_pcm_format_set_silence(runtime->format, dst + dst_off,
374 bytes_to_frames(runtime, size) *
375 runtime->channels);
376 dpcm->silent_size += size;
377 bytes -= size;
378 if (!bytes)
379 break;
380 dst_off = 0;
381 }
382 }
383
384 static void copy_play_buf(struct loopback_pcm *play,
385 struct loopback_pcm *capt,
386 unsigned int bytes)
387 {
388 struct snd_pcm_runtime *runtime = play->substream->runtime;
389 char *src = runtime->dma_area;
390 char *dst = capt->substream->runtime->dma_area;
391 unsigned int src_off = play->buf_pos;
392 unsigned int dst_off = capt->buf_pos;
393 unsigned int clear_bytes = 0;
394
395
396
397 if (runtime->status->state == SNDRV_PCM_STATE_DRAINING &&
398 snd_pcm_playback_hw_avail(runtime) < runtime->buffer_size) {
399 snd_pcm_uframes_t appl_ptr, appl_ptr1, diff;
400 appl_ptr = appl_ptr1 = runtime->control->appl_ptr;
401 appl_ptr1 -= appl_ptr1 % runtime->buffer_size;
402 appl_ptr1 += play->buf_pos / play->pcm_salign;
403 if (appl_ptr < appl_ptr1)
404 appl_ptr1 -= runtime->buffer_size;
405 diff = (appl_ptr - appl_ptr1) * play->pcm_salign;
406 if (diff < bytes) {
407 clear_bytes = bytes - diff;
408 bytes = diff;
409 }
410 }
411
412 for (;;) {
413 unsigned int size = bytes;
414 if (src_off + size > play->pcm_buffer_size)
415 size = play->pcm_buffer_size - src_off;
416 if (dst_off + size > capt->pcm_buffer_size)
417 size = capt->pcm_buffer_size - dst_off;
418 memcpy(dst + dst_off, src + src_off, size);
419 capt->silent_size = 0;
420 bytes -= size;
421 if (!bytes)
422 break;
423 src_off = (src_off + size) % play->pcm_buffer_size;
424 dst_off = (dst_off + size) % capt->pcm_buffer_size;
425 }
426
427 if (clear_bytes > 0) {
428 clear_capture_buf(capt, clear_bytes);
429 capt->silent_size = 0;
430 }
431 }
432
433 static inline unsigned int bytepos_delta(struct loopback_pcm *dpcm,
434 unsigned int jiffies_delta)
435 {
436 unsigned long last_pos;
437 unsigned int delta;
438
439 last_pos = byte_pos(dpcm, dpcm->irq_pos);
440 dpcm->irq_pos += jiffies_delta * dpcm->pcm_bps;
441 delta = byte_pos(dpcm, dpcm->irq_pos) - last_pos;
442 if (delta >= dpcm->last_drift)
443 delta -= dpcm->last_drift;
444 dpcm->last_drift = 0;
445 if (dpcm->irq_pos >= dpcm->period_size_frac) {
446 dpcm->irq_pos %= dpcm->period_size_frac;
447 dpcm->period_update_pending = 1;
448 }
449 return delta;
450 }
451
452 static inline void bytepos_finish(struct loopback_pcm *dpcm,
453 unsigned int delta)
454 {
455 dpcm->buf_pos += delta;
456 dpcm->buf_pos %= dpcm->pcm_buffer_size;
457 }
458
459
460 static unsigned int loopback_pos_update(struct loopback_cable *cable)
461 {
462 struct loopback_pcm *dpcm_play =
463 cable->streams[SNDRV_PCM_STREAM_PLAYBACK];
464 struct loopback_pcm *dpcm_capt =
465 cable->streams[SNDRV_PCM_STREAM_CAPTURE];
466 unsigned long delta_play = 0, delta_capt = 0;
467 unsigned int running, count1, count2;
468
469 running = cable->running ^ cable->pause;
470 if (running & (1 << SNDRV_PCM_STREAM_PLAYBACK)) {
471 delta_play = jiffies - dpcm_play->last_jiffies;
472 dpcm_play->last_jiffies += delta_play;
473 }
474
475 if (running & (1 << SNDRV_PCM_STREAM_CAPTURE)) {
476 delta_capt = jiffies - dpcm_capt->last_jiffies;
477 dpcm_capt->last_jiffies += delta_capt;
478 }
479
480 if (delta_play == 0 && delta_capt == 0)
481 goto unlock;
482
483 if (delta_play > delta_capt) {
484 count1 = bytepos_delta(dpcm_play, delta_play - delta_capt);
485 bytepos_finish(dpcm_play, count1);
486 delta_play = delta_capt;
487 } else if (delta_play < delta_capt) {
488 count1 = bytepos_delta(dpcm_capt, delta_capt - delta_play);
489 clear_capture_buf(dpcm_capt, count1);
490 bytepos_finish(dpcm_capt, count1);
491 delta_capt = delta_play;
492 }
493
494 if (delta_play == 0 && delta_capt == 0)
495 goto unlock;
496
497
498 count1 = bytepos_delta(dpcm_play, delta_play);
499 count2 = bytepos_delta(dpcm_capt, delta_capt);
500 if (count1 < count2) {
501 dpcm_capt->last_drift = count2 - count1;
502 count1 = count2;
503 } else if (count1 > count2) {
504 dpcm_play->last_drift = count1 - count2;
505 }
506 copy_play_buf(dpcm_play, dpcm_capt, count1);
507 bytepos_finish(dpcm_play, count1);
508 bytepos_finish(dpcm_capt, count1);
509 unlock:
510 return running;
511 }
512
513 static void loopback_timer_function(struct timer_list *t)
514 {
515 struct loopback_pcm *dpcm = from_timer(dpcm, t, timer);
516 unsigned long flags;
517
518 spin_lock_irqsave(&dpcm->cable->lock, flags);
519 if (loopback_pos_update(dpcm->cable) & (1 << dpcm->substream->stream)) {
520 loopback_timer_start(dpcm);
521 if (dpcm->period_update_pending) {
522 dpcm->period_update_pending = 0;
523 spin_unlock_irqrestore(&dpcm->cable->lock, flags);
524
525 snd_pcm_period_elapsed(dpcm->substream);
526 return;
527 }
528 }
529 spin_unlock_irqrestore(&dpcm->cable->lock, flags);
530 }
531
532 static snd_pcm_uframes_t loopback_pointer(struct snd_pcm_substream *substream)
533 {
534 struct snd_pcm_runtime *runtime = substream->runtime;
535 struct loopback_pcm *dpcm = runtime->private_data;
536 snd_pcm_uframes_t pos;
537
538 spin_lock(&dpcm->cable->lock);
539 loopback_pos_update(dpcm->cable);
540 pos = dpcm->buf_pos;
541 spin_unlock(&dpcm->cable->lock);
542 return bytes_to_frames(runtime, pos);
543 }
544
545 static const struct snd_pcm_hardware loopback_pcm_hardware =
546 {
547 .info = (SNDRV_PCM_INFO_INTERLEAVED | SNDRV_PCM_INFO_MMAP |
548 SNDRV_PCM_INFO_MMAP_VALID | SNDRV_PCM_INFO_PAUSE |
549 SNDRV_PCM_INFO_RESUME),
550 .formats = (SNDRV_PCM_FMTBIT_S16_LE | SNDRV_PCM_FMTBIT_S16_BE |
551 SNDRV_PCM_FMTBIT_S24_LE | SNDRV_PCM_FMTBIT_S24_BE |
552 SNDRV_PCM_FMTBIT_S24_3LE | SNDRV_PCM_FMTBIT_S24_3BE |
553 SNDRV_PCM_FMTBIT_S32_LE | SNDRV_PCM_FMTBIT_S32_BE |
554 SNDRV_PCM_FMTBIT_FLOAT_LE | SNDRV_PCM_FMTBIT_FLOAT_BE),
555 .rates = SNDRV_PCM_RATE_CONTINUOUS | SNDRV_PCM_RATE_8000_192000,
556 .rate_min = 8000,
557 .rate_max = 192000,
558 .channels_min = 1,
559 .channels_max = 32,
560 .buffer_bytes_max = 2 * 1024 * 1024,
561 .period_bytes_min = 64,
562
563
564 .period_bytes_max = 1024 * 1024,
565 .periods_min = 1,
566 .periods_max = 1024,
567 .fifo_size = 0,
568 };
569
570 static void loopback_runtime_free(struct snd_pcm_runtime *runtime)
571 {
572 struct loopback_pcm *dpcm = runtime->private_data;
573 kfree(dpcm);
574 }
575
576 static int loopback_hw_params(struct snd_pcm_substream *substream,
577 struct snd_pcm_hw_params *params)
578 {
579 return snd_pcm_lib_alloc_vmalloc_buffer(substream,
580 params_buffer_bytes(params));
581 }
582
583 static int loopback_hw_free(struct snd_pcm_substream *substream)
584 {
585 struct snd_pcm_runtime *runtime = substream->runtime;
586 struct loopback_pcm *dpcm = runtime->private_data;
587 struct loopback_cable *cable = dpcm->cable;
588
589 mutex_lock(&dpcm->loopback->cable_lock);
590 cable->valid &= ~(1 << substream->stream);
591 mutex_unlock(&dpcm->loopback->cable_lock);
592 return snd_pcm_lib_free_vmalloc_buffer(substream);
593 }
594
595 static unsigned int get_cable_index(struct snd_pcm_substream *substream)
596 {
597 if (!substream->pcm->device)
598 return substream->stream;
599 else
600 return !substream->stream;
601 }
602
603 static int rule_format(struct snd_pcm_hw_params *params,
604 struct snd_pcm_hw_rule *rule)
605 {
606 struct loopback_pcm *dpcm = rule->private;
607 struct loopback_cable *cable = dpcm->cable;
608 struct snd_mask m;
609
610 snd_mask_none(&m);
611 mutex_lock(&dpcm->loopback->cable_lock);
612 m.bits[0] = (u_int32_t)cable->hw.formats;
613 m.bits[1] = (u_int32_t)(cable->hw.formats >> 32);
614 mutex_unlock(&dpcm->loopback->cable_lock);
615 return snd_mask_refine(hw_param_mask(params, rule->var), &m);
616 }
617
618 static int rule_rate(struct snd_pcm_hw_params *params,
619 struct snd_pcm_hw_rule *rule)
620 {
621 struct loopback_pcm *dpcm = rule->private;
622 struct loopback_cable *cable = dpcm->cable;
623 struct snd_interval t;
624
625 mutex_lock(&dpcm->loopback->cable_lock);
626 t.min = cable->hw.rate_min;
627 t.max = cable->hw.rate_max;
628 mutex_unlock(&dpcm->loopback->cable_lock);
629 t.openmin = t.openmax = 0;
630 t.integer = 0;
631 return snd_interval_refine(hw_param_interval(params, rule->var), &t);
632 }
633
634 static int rule_channels(struct snd_pcm_hw_params *params,
635 struct snd_pcm_hw_rule *rule)
636 {
637 struct loopback_pcm *dpcm = rule->private;
638 struct loopback_cable *cable = dpcm->cable;
639 struct snd_interval t;
640
641 mutex_lock(&dpcm->loopback->cable_lock);
642 t.min = cable->hw.channels_min;
643 t.max = cable->hw.channels_max;
644 mutex_unlock(&dpcm->loopback->cable_lock);
645 t.openmin = t.openmax = 0;
646 t.integer = 0;
647 return snd_interval_refine(hw_param_interval(params, rule->var), &t);
648 }
649
650 static void free_cable(struct snd_pcm_substream *substream)
651 {
652 struct loopback *loopback = substream->private_data;
653 int dev = get_cable_index(substream);
654 struct loopback_cable *cable;
655
656 cable = loopback->cables[substream->number][dev];
657 if (!cable)
658 return;
659 if (cable->streams[!substream->stream]) {
660
661 spin_lock_irq(&cable->lock);
662 cable->streams[substream->stream] = NULL;
663 spin_unlock_irq(&cable->lock);
664 } else {
665
666 loopback->cables[substream->number][dev] = NULL;
667 kfree(cable);
668 }
669 }
670
671 static int loopback_open(struct snd_pcm_substream *substream)
672 {
673 struct snd_pcm_runtime *runtime = substream->runtime;
674 struct loopback *loopback = substream->private_data;
675 struct loopback_pcm *dpcm;
676 struct loopback_cable *cable = NULL;
677 int err = 0;
678 int dev = get_cable_index(substream);
679
680 mutex_lock(&loopback->cable_lock);
681 dpcm = kzalloc(sizeof(*dpcm), GFP_KERNEL);
682 if (!dpcm) {
683 err = -ENOMEM;
684 goto unlock;
685 }
686 dpcm->loopback = loopback;
687 dpcm->substream = substream;
688 timer_setup(&dpcm->timer, loopback_timer_function, 0);
689
690 cable = loopback->cables[substream->number][dev];
691 if (!cable) {
692 cable = kzalloc(sizeof(*cable), GFP_KERNEL);
693 if (!cable) {
694 err = -ENOMEM;
695 goto unlock;
696 }
697 spin_lock_init(&cable->lock);
698 cable->hw = loopback_pcm_hardware;
699 loopback->cables[substream->number][dev] = cable;
700 }
701 dpcm->cable = cable;
702
703 snd_pcm_hw_constraint_integer(runtime, SNDRV_PCM_HW_PARAM_PERIODS);
704
705
706
707
708 err = snd_pcm_hw_rule_add(runtime, 0,
709 SNDRV_PCM_HW_PARAM_FORMAT,
710 rule_format, dpcm,
711 SNDRV_PCM_HW_PARAM_FORMAT, -1);
712 if (err < 0)
713 goto unlock;
714 err = snd_pcm_hw_rule_add(runtime, 0,
715 SNDRV_PCM_HW_PARAM_RATE,
716 rule_rate, dpcm,
717 SNDRV_PCM_HW_PARAM_RATE, -1);
718 if (err < 0)
719 goto unlock;
720 err = snd_pcm_hw_rule_add(runtime, 0,
721 SNDRV_PCM_HW_PARAM_CHANNELS,
722 rule_channels, dpcm,
723 SNDRV_PCM_HW_PARAM_CHANNELS, -1);
724 if (err < 0)
725 goto unlock;
726
727 runtime->private_data = dpcm;
728 runtime->private_free = loopback_runtime_free;
729 if (get_notify(dpcm))
730 runtime->hw = loopback_pcm_hardware;
731 else
732 runtime->hw = cable->hw;
733
734 spin_lock_irq(&cable->lock);
735 cable->streams[substream->stream] = dpcm;
736 spin_unlock_irq(&cable->lock);
737
738 unlock:
739 if (err < 0) {
740 free_cable(substream);
741 kfree(dpcm);
742 }
743 mutex_unlock(&loopback->cable_lock);
744 return err;
745 }
746
747 static int loopback_close(struct snd_pcm_substream *substream)
748 {
749 struct loopback *loopback = substream->private_data;
750 struct loopback_pcm *dpcm = substream->runtime->private_data;
751
752 loopback_timer_stop_sync(dpcm);
753 mutex_lock(&loopback->cable_lock);
754 free_cable(substream);
755 mutex_unlock(&loopback->cable_lock);
756 return 0;
757 }
758
759 static const struct snd_pcm_ops loopback_pcm_ops = {
760 .open = loopback_open,
761 .close = loopback_close,
762 .ioctl = snd_pcm_lib_ioctl,
763 .hw_params = loopback_hw_params,
764 .hw_free = loopback_hw_free,
765 .prepare = loopback_prepare,
766 .trigger = loopback_trigger,
767 .pointer = loopback_pointer,
768 .page = snd_pcm_lib_get_vmalloc_page,
769 };
770
771 static int loopback_pcm_new(struct loopback *loopback,
772 int device, int substreams)
773 {
774 struct snd_pcm *pcm;
775 int err;
776
777 err = snd_pcm_new(loopback->card, "Loopback PCM", device,
778 substreams, substreams, &pcm);
779 if (err < 0)
780 return err;
781 snd_pcm_set_ops(pcm, SNDRV_PCM_STREAM_PLAYBACK, &loopback_pcm_ops);
782 snd_pcm_set_ops(pcm, SNDRV_PCM_STREAM_CAPTURE, &loopback_pcm_ops);
783
784 pcm->private_data = loopback;
785 pcm->info_flags = 0;
786 strcpy(pcm->name, "Loopback PCM");
787
788 loopback->pcm[device] = pcm;
789 return 0;
790 }
791
792 static int loopback_rate_shift_info(struct snd_kcontrol *kcontrol,
793 struct snd_ctl_elem_info *uinfo)
794 {
795 uinfo->type = SNDRV_CTL_ELEM_TYPE_INTEGER;
796 uinfo->count = 1;
797 uinfo->value.integer.min = 80000;
798 uinfo->value.integer.max = 120000;
799 uinfo->value.integer.step = 1;
800 return 0;
801 }
802
803 static int loopback_rate_shift_get(struct snd_kcontrol *kcontrol,
804 struct snd_ctl_elem_value *ucontrol)
805 {
806 struct loopback *loopback = snd_kcontrol_chip(kcontrol);
807
808 mutex_lock(&loopback->cable_lock);
809 ucontrol->value.integer.value[0] =
810 loopback->setup[kcontrol->id.subdevice]
811 [kcontrol->id.device].rate_shift;
812 mutex_unlock(&loopback->cable_lock);
813 return 0;
814 }
815
816 static int loopback_rate_shift_put(struct snd_kcontrol *kcontrol,
817 struct snd_ctl_elem_value *ucontrol)
818 {
819 struct loopback *loopback = snd_kcontrol_chip(kcontrol);
820 unsigned int val;
821 int change = 0;
822
823 val = ucontrol->value.integer.value[0];
824 if (val < 80000)
825 val = 80000;
826 if (val > 120000)
827 val = 120000;
828 mutex_lock(&loopback->cable_lock);
829 if (val != loopback->setup[kcontrol->id.subdevice]
830 [kcontrol->id.device].rate_shift) {
831 loopback->setup[kcontrol->id.subdevice]
832 [kcontrol->id.device].rate_shift = val;
833 change = 1;
834 }
835 mutex_unlock(&loopback->cable_lock);
836 return change;
837 }
838
839 static int loopback_notify_get(struct snd_kcontrol *kcontrol,
840 struct snd_ctl_elem_value *ucontrol)
841 {
842 struct loopback *loopback = snd_kcontrol_chip(kcontrol);
843
844 mutex_lock(&loopback->cable_lock);
845 ucontrol->value.integer.value[0] =
846 loopback->setup[kcontrol->id.subdevice]
847 [kcontrol->id.device].notify;
848 mutex_unlock(&loopback->cable_lock);
849 return 0;
850 }
851
852 static int loopback_notify_put(struct snd_kcontrol *kcontrol,
853 struct snd_ctl_elem_value *ucontrol)
854 {
855 struct loopback *loopback = snd_kcontrol_chip(kcontrol);
856 unsigned int val;
857 int change = 0;
858
859 val = ucontrol->value.integer.value[0] ? 1 : 0;
860 mutex_lock(&loopback->cable_lock);
861 if (val != loopback->setup[kcontrol->id.subdevice]
862 [kcontrol->id.device].notify) {
863 loopback->setup[kcontrol->id.subdevice]
864 [kcontrol->id.device].notify = val;
865 change = 1;
866 }
867 mutex_unlock(&loopback->cable_lock);
868 return change;
869 }
870
871 static int loopback_active_get(struct snd_kcontrol *kcontrol,
872 struct snd_ctl_elem_value *ucontrol)
873 {
874 struct loopback *loopback = snd_kcontrol_chip(kcontrol);
875 struct loopback_cable *cable;
876
877 unsigned int val = 0;
878
879 mutex_lock(&loopback->cable_lock);
880 cable = loopback->cables[kcontrol->id.subdevice][kcontrol->id.device ^ 1];
881 if (cable != NULL) {
882 unsigned int running = cable->running ^ cable->pause;
883
884 val = (running & (1 << SNDRV_PCM_STREAM_PLAYBACK)) ? 1 : 0;
885 }
886 mutex_unlock(&loopback->cable_lock);
887 ucontrol->value.integer.value[0] = val;
888 return 0;
889 }
890
891 static int loopback_format_info(struct snd_kcontrol *kcontrol,
892 struct snd_ctl_elem_info *uinfo)
893 {
894 uinfo->type = SNDRV_CTL_ELEM_TYPE_INTEGER;
895 uinfo->count = 1;
896 uinfo->value.integer.min = 0;
897 uinfo->value.integer.max = SNDRV_PCM_FORMAT_LAST;
898 uinfo->value.integer.step = 1;
899 return 0;
900 }
901
902 static int loopback_format_get(struct snd_kcontrol *kcontrol,
903 struct snd_ctl_elem_value *ucontrol)
904 {
905 struct loopback *loopback = snd_kcontrol_chip(kcontrol);
906
907 ucontrol->value.integer.value[0] =
908 loopback->setup[kcontrol->id.subdevice]
909 [kcontrol->id.device].format;
910 return 0;
911 }
912
913 static int loopback_rate_info(struct snd_kcontrol *kcontrol,
914 struct snd_ctl_elem_info *uinfo)
915 {
916 uinfo->type = SNDRV_CTL_ELEM_TYPE_INTEGER;
917 uinfo->count = 1;
918 uinfo->value.integer.min = 0;
919 uinfo->value.integer.max = 192000;
920 uinfo->value.integer.step = 1;
921 return 0;
922 }
923
924 static int loopback_rate_get(struct snd_kcontrol *kcontrol,
925 struct snd_ctl_elem_value *ucontrol)
926 {
927 struct loopback *loopback = snd_kcontrol_chip(kcontrol);
928
929 mutex_lock(&loopback->cable_lock);
930 ucontrol->value.integer.value[0] =
931 loopback->setup[kcontrol->id.subdevice]
932 [kcontrol->id.device].rate;
933 mutex_unlock(&loopback->cable_lock);
934 return 0;
935 }
936
937 static int loopback_channels_info(struct snd_kcontrol *kcontrol,
938 struct snd_ctl_elem_info *uinfo)
939 {
940 uinfo->type = SNDRV_CTL_ELEM_TYPE_INTEGER;
941 uinfo->count = 1;
942 uinfo->value.integer.min = 1;
943 uinfo->value.integer.max = 1024;
944 uinfo->value.integer.step = 1;
945 return 0;
946 }
947
948 static int loopback_channels_get(struct snd_kcontrol *kcontrol,
949 struct snd_ctl_elem_value *ucontrol)
950 {
951 struct loopback *loopback = snd_kcontrol_chip(kcontrol);
952
953 mutex_lock(&loopback->cable_lock);
954 ucontrol->value.integer.value[0] =
955 loopback->setup[kcontrol->id.subdevice]
956 [kcontrol->id.device].channels;
957 mutex_unlock(&loopback->cable_lock);
958 return 0;
959 }
960
961 static struct snd_kcontrol_new loopback_controls[] = {
962 {
963 .iface = SNDRV_CTL_ELEM_IFACE_PCM,
964 .name = "PCM Rate Shift 100000",
965 .info = loopback_rate_shift_info,
966 .get = loopback_rate_shift_get,
967 .put = loopback_rate_shift_put,
968 },
969 {
970 .iface = SNDRV_CTL_ELEM_IFACE_PCM,
971 .name = "PCM Notify",
972 .info = snd_ctl_boolean_mono_info,
973 .get = loopback_notify_get,
974 .put = loopback_notify_put,
975 },
976 #define ACTIVE_IDX 2
977 {
978 .access = SNDRV_CTL_ELEM_ACCESS_READ,
979 .iface = SNDRV_CTL_ELEM_IFACE_PCM,
980 .name = "PCM Slave Active",
981 .info = snd_ctl_boolean_mono_info,
982 .get = loopback_active_get,
983 },
984 #define FORMAT_IDX 3
985 {
986 .access = SNDRV_CTL_ELEM_ACCESS_READ,
987 .iface = SNDRV_CTL_ELEM_IFACE_PCM,
988 .name = "PCM Slave Format",
989 .info = loopback_format_info,
990 .get = loopback_format_get
991 },
992 #define RATE_IDX 4
993 {
994 .access = SNDRV_CTL_ELEM_ACCESS_READ,
995 .iface = SNDRV_CTL_ELEM_IFACE_PCM,
996 .name = "PCM Slave Rate",
997 .info = loopback_rate_info,
998 .get = loopback_rate_get
999 },
1000 #define CHANNELS_IDX 5
1001 {
1002 .access = SNDRV_CTL_ELEM_ACCESS_READ,
1003 .iface = SNDRV_CTL_ELEM_IFACE_PCM,
1004 .name = "PCM Slave Channels",
1005 .info = loopback_channels_info,
1006 .get = loopback_channels_get
1007 }
1008 };
1009
1010 static int loopback_mixer_new(struct loopback *loopback, int notify)
1011 {
1012 struct snd_card *card = loopback->card;
1013 struct snd_pcm *pcm;
1014 struct snd_kcontrol *kctl;
1015 struct loopback_setup *setup;
1016 int err, dev, substr, substr_count, idx;
1017
1018 strcpy(card->mixername, "Loopback Mixer");
1019 for (dev = 0; dev < 2; dev++) {
1020 pcm = loopback->pcm[dev];
1021 substr_count =
1022 pcm->streams[SNDRV_PCM_STREAM_CAPTURE].substream_count;
1023 for (substr = 0; substr < substr_count; substr++) {
1024 setup = &loopback->setup[substr][dev];
1025 setup->notify = notify;
1026 setup->rate_shift = NO_PITCH;
1027 setup->format = SNDRV_PCM_FORMAT_S16_LE;
1028 setup->rate = 48000;
1029 setup->channels = 2;
1030 for (idx = 0; idx < ARRAY_SIZE(loopback_controls);
1031 idx++) {
1032 kctl = snd_ctl_new1(&loopback_controls[idx],
1033 loopback);
1034 if (!kctl)
1035 return -ENOMEM;
1036 kctl->id.device = dev;
1037 kctl->id.subdevice = substr;
1038 switch (idx) {
1039 case ACTIVE_IDX:
1040 setup->active_id = kctl->id;
1041 break;
1042 case FORMAT_IDX:
1043 setup->format_id = kctl->id;
1044 break;
1045 case RATE_IDX:
1046 setup->rate_id = kctl->id;
1047 break;
1048 case CHANNELS_IDX:
1049 setup->channels_id = kctl->id;
1050 break;
1051 default:
1052 break;
1053 }
1054 err = snd_ctl_add(card, kctl);
1055 if (err < 0)
1056 return err;
1057 }
1058 }
1059 }
1060 return 0;
1061 }
1062
1063 static void print_dpcm_info(struct snd_info_buffer *buffer,
1064 struct loopback_pcm *dpcm,
1065 const char *id)
1066 {
1067 snd_iprintf(buffer, " %s\n", id);
1068 if (dpcm == NULL) {
1069 snd_iprintf(buffer, " inactive\n");
1070 return;
1071 }
1072 snd_iprintf(buffer, " buffer_size:\t%u\n", dpcm->pcm_buffer_size);
1073 snd_iprintf(buffer, " buffer_pos:\t\t%u\n", dpcm->buf_pos);
1074 snd_iprintf(buffer, " silent_size:\t%u\n", dpcm->silent_size);
1075 snd_iprintf(buffer, " period_size:\t%u\n", dpcm->pcm_period_size);
1076 snd_iprintf(buffer, " bytes_per_sec:\t%u\n", dpcm->pcm_bps);
1077 snd_iprintf(buffer, " sample_align:\t%u\n", dpcm->pcm_salign);
1078 snd_iprintf(buffer, " rate_shift:\t\t%u\n", dpcm->pcm_rate_shift);
1079 snd_iprintf(buffer, " update_pending:\t%u\n",
1080 dpcm->period_update_pending);
1081 snd_iprintf(buffer, " irq_pos:\t\t%u\n", dpcm->irq_pos);
1082 snd_iprintf(buffer, " period_frac:\t%u\n", dpcm->period_size_frac);
1083 snd_iprintf(buffer, " last_jiffies:\t%lu (%lu)\n",
1084 dpcm->last_jiffies, jiffies);
1085 snd_iprintf(buffer, " timer_expires:\t%lu\n", dpcm->timer.expires);
1086 }
1087
1088 static void print_substream_info(struct snd_info_buffer *buffer,
1089 struct loopback *loopback,
1090 int sub,
1091 int num)
1092 {
1093 struct loopback_cable *cable = loopback->cables[sub][num];
1094
1095 snd_iprintf(buffer, "Cable %i substream %i:\n", num, sub);
1096 if (cable == NULL) {
1097 snd_iprintf(buffer, " inactive\n");
1098 return;
1099 }
1100 snd_iprintf(buffer, " valid: %u\n", cable->valid);
1101 snd_iprintf(buffer, " running: %u\n", cable->running);
1102 snd_iprintf(buffer, " pause: %u\n", cable->pause);
1103 print_dpcm_info(buffer, cable->streams[0], "Playback");
1104 print_dpcm_info(buffer, cable->streams[1], "Capture");
1105 }
1106
1107 static void print_cable_info(struct snd_info_entry *entry,
1108 struct snd_info_buffer *buffer)
1109 {
1110 struct loopback *loopback = entry->private_data;
1111 int sub, num;
1112
1113 mutex_lock(&loopback->cable_lock);
1114 num = entry->name[strlen(entry->name)-1];
1115 num = num == '0' ? 0 : 1;
1116 for (sub = 0; sub < MAX_PCM_SUBSTREAMS; sub++)
1117 print_substream_info(buffer, loopback, sub, num);
1118 mutex_unlock(&loopback->cable_lock);
1119 }
1120
1121 static int loopback_proc_new(struct loopback *loopback, int cidx)
1122 {
1123 char name[32];
1124
1125 snprintf(name, sizeof(name), "cable#%d", cidx);
1126 return snd_card_ro_proc_new(loopback->card, name, loopback,
1127 print_cable_info);
1128 }
1129
1130 static int loopback_probe(struct platform_device *devptr)
1131 {
1132 struct snd_card *card;
1133 struct loopback *loopback;
1134 int dev = devptr->id;
1135 int err;
1136
1137 err = snd_card_new(&devptr->dev, index[dev], id[dev], THIS_MODULE,
1138 sizeof(struct loopback), &card);
1139 if (err < 0)
1140 return err;
1141 loopback = card->private_data;
1142
1143 if (pcm_substreams[dev] < 1)
1144 pcm_substreams[dev] = 1;
1145 if (pcm_substreams[dev] > MAX_PCM_SUBSTREAMS)
1146 pcm_substreams[dev] = MAX_PCM_SUBSTREAMS;
1147
1148 loopback->card = card;
1149 mutex_init(&loopback->cable_lock);
1150
1151 err = loopback_pcm_new(loopback, 0, pcm_substreams[dev]);
1152 if (err < 0)
1153 goto __nodev;
1154 err = loopback_pcm_new(loopback, 1, pcm_substreams[dev]);
1155 if (err < 0)
1156 goto __nodev;
1157 err = loopback_mixer_new(loopback, pcm_notify[dev] ? 1 : 0);
1158 if (err < 0)
1159 goto __nodev;
1160 loopback_proc_new(loopback, 0);
1161 loopback_proc_new(loopback, 1);
1162 strcpy(card->driver, "Loopback");
1163 strcpy(card->shortname, "Loopback");
1164 sprintf(card->longname, "Loopback %i", dev + 1);
1165 err = snd_card_register(card);
1166 if (!err) {
1167 platform_set_drvdata(devptr, card);
1168 return 0;
1169 }
1170 __nodev:
1171 snd_card_free(card);
1172 return err;
1173 }
1174
1175 static int loopback_remove(struct platform_device *devptr)
1176 {
1177 snd_card_free(platform_get_drvdata(devptr));
1178 return 0;
1179 }
1180
1181 #ifdef CONFIG_PM_SLEEP
1182 static int loopback_suspend(struct device *pdev)
1183 {
1184 struct snd_card *card = dev_get_drvdata(pdev);
1185
1186 snd_power_change_state(card, SNDRV_CTL_POWER_D3hot);
1187 return 0;
1188 }
1189
1190 static int loopback_resume(struct device *pdev)
1191 {
1192 struct snd_card *card = dev_get_drvdata(pdev);
1193
1194 snd_power_change_state(card, SNDRV_CTL_POWER_D0);
1195 return 0;
1196 }
1197
1198 static SIMPLE_DEV_PM_OPS(loopback_pm, loopback_suspend, loopback_resume);
1199 #define LOOPBACK_PM_OPS &loopback_pm
1200 #else
1201 #define LOOPBACK_PM_OPS NULL
1202 #endif
1203
1204 #define SND_LOOPBACK_DRIVER "snd_aloop"
1205
1206 static struct platform_driver loopback_driver = {
1207 .probe = loopback_probe,
1208 .remove = loopback_remove,
1209 .driver = {
1210 .name = SND_LOOPBACK_DRIVER,
1211 .pm = LOOPBACK_PM_OPS,
1212 },
1213 };
1214
1215 static void loopback_unregister_all(void)
1216 {
1217 int i;
1218
1219 for (i = 0; i < ARRAY_SIZE(devices); ++i)
1220 platform_device_unregister(devices[i]);
1221 platform_driver_unregister(&loopback_driver);
1222 }
1223
1224 static int __init alsa_card_loopback_init(void)
1225 {
1226 int i, err, cards;
1227
1228 err = platform_driver_register(&loopback_driver);
1229 if (err < 0)
1230 return err;
1231
1232
1233 cards = 0;
1234 for (i = 0; i < SNDRV_CARDS; i++) {
1235 struct platform_device *device;
1236 if (!enable[i])
1237 continue;
1238 device = platform_device_register_simple(SND_LOOPBACK_DRIVER,
1239 i, NULL, 0);
1240 if (IS_ERR(device))
1241 continue;
1242 if (!platform_get_drvdata(device)) {
1243 platform_device_unregister(device);
1244 continue;
1245 }
1246 devices[i] = device;
1247 cards++;
1248 }
1249 if (!cards) {
1250 #ifdef MODULE
1251 printk(KERN_ERR "aloop: No loopback enabled\n");
1252 #endif
1253 loopback_unregister_all();
1254 return -ENODEV;
1255 }
1256 return 0;
1257 }
1258
1259 static void __exit alsa_card_loopback_exit(void)
1260 {
1261 loopback_unregister_all();
1262 }
1263
1264 module_init(alsa_card_loopback_init)
1265 module_exit(alsa_card_loopback_exit)