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TOMOYO Linux Cross Reference
Linux/sound/drivers/aloop.c

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  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 ─░nan <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                 if (substream->stream == SNDRV_PCM_STREAM_PLAYBACK)
300                         loopback_active_notify(dpcm);
301                 break;
302         case SNDRV_PCM_TRIGGER_PAUSE_RELEASE:
303         case SNDRV_PCM_TRIGGER_RESUME:
304                 spin_lock(&cable->lock);
305                 dpcm->last_jiffies = jiffies;
306                 cable->pause &= ~stream;
307                 loopback_timer_start(dpcm);
308                 spin_unlock(&cable->lock);
309                 if (substream->stream == SNDRV_PCM_STREAM_PLAYBACK)
310                         loopback_active_notify(dpcm);
311                 break;
312         default:
313                 return -EINVAL;
314         }
315         return 0;
316 }
317 
318 static void params_change(struct snd_pcm_substream *substream)
319 {
320         struct snd_pcm_runtime *runtime = substream->runtime;
321         struct loopback_pcm *dpcm = runtime->private_data;
322         struct loopback_cable *cable = dpcm->cable;
323 
324         cable->hw.formats = pcm_format_to_bits(runtime->format);
325         cable->hw.rate_min = runtime->rate;
326         cable->hw.rate_max = runtime->rate;
327         cable->hw.channels_min = runtime->channels;
328         cable->hw.channels_max = runtime->channels;
329 }
330 
331 static int loopback_prepare(struct snd_pcm_substream *substream)
332 {
333         struct snd_pcm_runtime *runtime = substream->runtime;
334         struct loopback_pcm *dpcm = runtime->private_data;
335         struct loopback_cable *cable = dpcm->cable;
336         int bps, salign;
337 
338         loopback_timer_stop_sync(dpcm);
339 
340         salign = (snd_pcm_format_width(runtime->format) *
341                                                 runtime->channels) / 8;
342         bps = salign * runtime->rate;
343         if (bps <= 0 || salign <= 0)
344                 return -EINVAL;
345 
346         dpcm->buf_pos = 0;
347         dpcm->pcm_buffer_size = frames_to_bytes(runtime, runtime->buffer_size);
348         if (substream->stream == SNDRV_PCM_STREAM_CAPTURE) {
349                 /* clear capture buffer */
350                 dpcm->silent_size = dpcm->pcm_buffer_size;
351                 snd_pcm_format_set_silence(runtime->format, runtime->dma_area,
352                                            runtime->buffer_size * runtime->channels);
353         }
354 
355         dpcm->irq_pos = 0;
356         dpcm->period_update_pending = 0;
357         dpcm->pcm_bps = bps;
358         dpcm->pcm_salign = salign;
359         dpcm->pcm_period_size = frames_to_bytes(runtime, runtime->period_size);
360 
361         mutex_lock(&dpcm->loopback->cable_lock);
362         if (!(cable->valid & ~(1 << substream->stream)) ||
363             (get_setup(dpcm)->notify &&
364              substream->stream == SNDRV_PCM_STREAM_PLAYBACK))
365                 params_change(substream);
366         cable->valid |= 1 << substream->stream;
367         mutex_unlock(&dpcm->loopback->cable_lock);
368 
369         return 0;
370 }
371 
372 static void clear_capture_buf(struct loopback_pcm *dpcm, unsigned int bytes)
373 {
374         struct snd_pcm_runtime *runtime = dpcm->substream->runtime;
375         char *dst = runtime->dma_area;
376         unsigned int dst_off = dpcm->buf_pos;
377 
378         if (dpcm->silent_size >= dpcm->pcm_buffer_size)
379                 return;
380         if (dpcm->silent_size + bytes > dpcm->pcm_buffer_size)
381                 bytes = dpcm->pcm_buffer_size - dpcm->silent_size;
382 
383         for (;;) {
384                 unsigned int size = bytes;
385                 if (dst_off + size > dpcm->pcm_buffer_size)
386                         size = dpcm->pcm_buffer_size - dst_off;
387                 snd_pcm_format_set_silence(runtime->format, dst + dst_off,
388                                            bytes_to_frames(runtime, size) *
389                                                 runtime->channels);
390                 dpcm->silent_size += size;
391                 bytes -= size;
392                 if (!bytes)
393                         break;
394                 dst_off = 0;
395         }
396 }
397 
398 static void copy_play_buf(struct loopback_pcm *play,
399                           struct loopback_pcm *capt,
400                           unsigned int bytes)
401 {
402         struct snd_pcm_runtime *runtime = play->substream->runtime;
403         char *src = runtime->dma_area;
404         char *dst = capt->substream->runtime->dma_area;
405         unsigned int src_off = play->buf_pos;
406         unsigned int dst_off = capt->buf_pos;
407         unsigned int clear_bytes = 0;
408 
409         /* check if playback is draining, trim the capture copy size
410          * when our pointer is at the end of playback ring buffer */
411         if (runtime->status->state == SNDRV_PCM_STATE_DRAINING &&
412             snd_pcm_playback_hw_avail(runtime) < runtime->buffer_size) { 
413                 snd_pcm_uframes_t appl_ptr, appl_ptr1, diff;
414                 appl_ptr = appl_ptr1 = runtime->control->appl_ptr;
415                 appl_ptr1 -= appl_ptr1 % runtime->buffer_size;
416                 appl_ptr1 += play->buf_pos / play->pcm_salign;
417                 if (appl_ptr < appl_ptr1)
418                         appl_ptr1 -= runtime->buffer_size;
419                 diff = (appl_ptr - appl_ptr1) * play->pcm_salign;
420                 if (diff < bytes) {
421                         clear_bytes = bytes - diff;
422                         bytes = diff;
423                 }
424         }
425 
426         for (;;) {
427                 unsigned int size = bytes;
428                 if (src_off + size > play->pcm_buffer_size)
429                         size = play->pcm_buffer_size - src_off;
430                 if (dst_off + size > capt->pcm_buffer_size)
431                         size = capt->pcm_buffer_size - dst_off;
432                 memcpy(dst + dst_off, src + src_off, size);
433                 capt->silent_size = 0;
434                 bytes -= size;
435                 if (!bytes)
436                         break;
437                 src_off = (src_off + size) % play->pcm_buffer_size;
438                 dst_off = (dst_off + size) % capt->pcm_buffer_size;
439         }
440 
441         if (clear_bytes > 0) {
442                 clear_capture_buf(capt, clear_bytes);
443                 capt->silent_size = 0;
444         }
445 }
446 
447 static inline unsigned int bytepos_delta(struct loopback_pcm *dpcm,
448                                          unsigned int jiffies_delta)
449 {
450         unsigned long last_pos;
451         unsigned int delta;
452 
453         last_pos = byte_pos(dpcm, dpcm->irq_pos);
454         dpcm->irq_pos += jiffies_delta * dpcm->pcm_bps;
455         delta = byte_pos(dpcm, dpcm->irq_pos) - last_pos;
456         if (delta >= dpcm->last_drift)
457                 delta -= dpcm->last_drift;
458         dpcm->last_drift = 0;
459         if (dpcm->irq_pos >= dpcm->period_size_frac) {
460                 dpcm->irq_pos %= dpcm->period_size_frac;
461                 dpcm->period_update_pending = 1;
462         }
463         return delta;
464 }
465 
466 static inline void bytepos_finish(struct loopback_pcm *dpcm,
467                                   unsigned int delta)
468 {
469         dpcm->buf_pos += delta;
470         dpcm->buf_pos %= dpcm->pcm_buffer_size;
471 }
472 
473 /* call in cable->lock */
474 static unsigned int loopback_pos_update(struct loopback_cable *cable)
475 {
476         struct loopback_pcm *dpcm_play =
477                         cable->streams[SNDRV_PCM_STREAM_PLAYBACK];
478         struct loopback_pcm *dpcm_capt =
479                         cable->streams[SNDRV_PCM_STREAM_CAPTURE];
480         unsigned long delta_play = 0, delta_capt = 0;
481         unsigned int running, count1, count2;
482 
483         running = cable->running ^ cable->pause;
484         if (running & (1 << SNDRV_PCM_STREAM_PLAYBACK)) {
485                 delta_play = jiffies - dpcm_play->last_jiffies;
486                 dpcm_play->last_jiffies += delta_play;
487         }
488 
489         if (running & (1 << SNDRV_PCM_STREAM_CAPTURE)) {
490                 delta_capt = jiffies - dpcm_capt->last_jiffies;
491                 dpcm_capt->last_jiffies += delta_capt;
492         }
493 
494         if (delta_play == 0 && delta_capt == 0)
495                 goto unlock;
496                 
497         if (delta_play > delta_capt) {
498                 count1 = bytepos_delta(dpcm_play, delta_play - delta_capt);
499                 bytepos_finish(dpcm_play, count1);
500                 delta_play = delta_capt;
501         } else if (delta_play < delta_capt) {
502                 count1 = bytepos_delta(dpcm_capt, delta_capt - delta_play);
503                 clear_capture_buf(dpcm_capt, count1);
504                 bytepos_finish(dpcm_capt, count1);
505                 delta_capt = delta_play;
506         }
507 
508         if (delta_play == 0 && delta_capt == 0)
509                 goto unlock;
510 
511         /* note delta_capt == delta_play at this moment */
512         count1 = bytepos_delta(dpcm_play, delta_play);
513         count2 = bytepos_delta(dpcm_capt, delta_capt);
514         if (count1 < count2) {
515                 dpcm_capt->last_drift = count2 - count1;
516                 count1 = count2;
517         } else if (count1 > count2) {
518                 dpcm_play->last_drift = count1 - count2;
519         }
520         copy_play_buf(dpcm_play, dpcm_capt, count1);
521         bytepos_finish(dpcm_play, count1);
522         bytepos_finish(dpcm_capt, count1);
523  unlock:
524         return running;
525 }
526 
527 static void loopback_timer_function(struct timer_list *t)
528 {
529         struct loopback_pcm *dpcm = from_timer(dpcm, t, timer);
530         unsigned long flags;
531 
532         spin_lock_irqsave(&dpcm->cable->lock, flags);
533         if (loopback_pos_update(dpcm->cable) & (1 << dpcm->substream->stream)) {
534                 loopback_timer_start(dpcm);
535                 if (dpcm->period_update_pending) {
536                         dpcm->period_update_pending = 0;
537                         spin_unlock_irqrestore(&dpcm->cable->lock, flags);
538                         /* need to unlock before calling below */
539                         snd_pcm_period_elapsed(dpcm->substream);
540                         return;
541                 }
542         }
543         spin_unlock_irqrestore(&dpcm->cable->lock, flags);
544 }
545 
546 static snd_pcm_uframes_t loopback_pointer(struct snd_pcm_substream *substream)
547 {
548         struct snd_pcm_runtime *runtime = substream->runtime;
549         struct loopback_pcm *dpcm = runtime->private_data;
550         snd_pcm_uframes_t pos;
551 
552         spin_lock(&dpcm->cable->lock);
553         loopback_pos_update(dpcm->cable);
554         pos = dpcm->buf_pos;
555         spin_unlock(&dpcm->cable->lock);
556         return bytes_to_frames(runtime, pos);
557 }
558 
559 static const struct snd_pcm_hardware loopback_pcm_hardware =
560 {
561         .info =         (SNDRV_PCM_INFO_INTERLEAVED | SNDRV_PCM_INFO_MMAP |
562                          SNDRV_PCM_INFO_MMAP_VALID | SNDRV_PCM_INFO_PAUSE |
563                          SNDRV_PCM_INFO_RESUME),
564         .formats =      (SNDRV_PCM_FMTBIT_S16_LE | SNDRV_PCM_FMTBIT_S16_BE |
565                          SNDRV_PCM_FMTBIT_S32_LE | SNDRV_PCM_FMTBIT_S32_BE |
566                          SNDRV_PCM_FMTBIT_FLOAT_LE | SNDRV_PCM_FMTBIT_FLOAT_BE),
567         .rates =        SNDRV_PCM_RATE_CONTINUOUS | SNDRV_PCM_RATE_8000_192000,
568         .rate_min =             8000,
569         .rate_max =             192000,
570         .channels_min =         1,
571         .channels_max =         32,
572         .buffer_bytes_max =     2 * 1024 * 1024,
573         .period_bytes_min =     64,
574         /* note check overflow in frac_pos() using pcm_rate_shift before
575            changing period_bytes_max value */
576         .period_bytes_max =     1024 * 1024,
577         .periods_min =          1,
578         .periods_max =          1024,
579         .fifo_size =            0,
580 };
581 
582 static void loopback_runtime_free(struct snd_pcm_runtime *runtime)
583 {
584         struct loopback_pcm *dpcm = runtime->private_data;
585         kfree(dpcm);
586 }
587 
588 static int loopback_hw_params(struct snd_pcm_substream *substream,
589                               struct snd_pcm_hw_params *params)
590 {
591         return snd_pcm_lib_alloc_vmalloc_buffer(substream,
592                                                 params_buffer_bytes(params));
593 }
594 
595 static int loopback_hw_free(struct snd_pcm_substream *substream)
596 {
597         struct snd_pcm_runtime *runtime = substream->runtime;
598         struct loopback_pcm *dpcm = runtime->private_data;
599         struct loopback_cable *cable = dpcm->cable;
600 
601         mutex_lock(&dpcm->loopback->cable_lock);
602         cable->valid &= ~(1 << substream->stream);
603         mutex_unlock(&dpcm->loopback->cable_lock);
604         return snd_pcm_lib_free_vmalloc_buffer(substream);
605 }
606 
607 static unsigned int get_cable_index(struct snd_pcm_substream *substream)
608 {
609         if (!substream->pcm->device)
610                 return substream->stream;
611         else
612                 return !substream->stream;
613 }
614 
615 static int rule_format(struct snd_pcm_hw_params *params,
616                        struct snd_pcm_hw_rule *rule)
617 {
618         struct loopback_pcm *dpcm = rule->private;
619         struct loopback_cable *cable = dpcm->cable;
620         struct snd_mask m;
621 
622         snd_mask_none(&m);
623         mutex_lock(&dpcm->loopback->cable_lock);
624         m.bits[0] = (u_int32_t)cable->hw.formats;
625         m.bits[1] = (u_int32_t)(cable->hw.formats >> 32);
626         mutex_unlock(&dpcm->loopback->cable_lock);
627         return snd_mask_refine(hw_param_mask(params, rule->var), &m);
628 }
629 
630 static int rule_rate(struct snd_pcm_hw_params *params,
631                      struct snd_pcm_hw_rule *rule)
632 {
633         struct loopback_pcm *dpcm = rule->private;
634         struct loopback_cable *cable = dpcm->cable;
635         struct snd_interval t;
636 
637         mutex_lock(&dpcm->loopback->cable_lock);
638         t.min = cable->hw.rate_min;
639         t.max = cable->hw.rate_max;
640         mutex_unlock(&dpcm->loopback->cable_lock);
641         t.openmin = t.openmax = 0;
642         t.integer = 0;
643         return snd_interval_refine(hw_param_interval(params, rule->var), &t);
644 }
645 
646 static int rule_channels(struct snd_pcm_hw_params *params,
647                          struct snd_pcm_hw_rule *rule)
648 {
649         struct loopback_pcm *dpcm = rule->private;
650         struct loopback_cable *cable = dpcm->cable;
651         struct snd_interval t;
652 
653         mutex_lock(&dpcm->loopback->cable_lock);
654         t.min = cable->hw.channels_min;
655         t.max = cable->hw.channels_max;
656         mutex_unlock(&dpcm->loopback->cable_lock);
657         t.openmin = t.openmax = 0;
658         t.integer = 0;
659         return snd_interval_refine(hw_param_interval(params, rule->var), &t);
660 }
661 
662 static void free_cable(struct snd_pcm_substream *substream)
663 {
664         struct loopback *loopback = substream->private_data;
665         int dev = get_cable_index(substream);
666         struct loopback_cable *cable;
667 
668         cable = loopback->cables[substream->number][dev];
669         if (!cable)
670                 return;
671         if (cable->streams[!substream->stream]) {
672                 /* other stream is still alive */
673                 spin_lock_irq(&cable->lock);
674                 cable->streams[substream->stream] = NULL;
675                 spin_unlock_irq(&cable->lock);
676         } else {
677                 /* free the cable */
678                 loopback->cables[substream->number][dev] = NULL;
679                 kfree(cable);
680         }
681 }
682 
683 static int loopback_open(struct snd_pcm_substream *substream)
684 {
685         struct snd_pcm_runtime *runtime = substream->runtime;
686         struct loopback *loopback = substream->private_data;
687         struct loopback_pcm *dpcm;
688         struct loopback_cable *cable = NULL;
689         int err = 0;
690         int dev = get_cable_index(substream);
691 
692         mutex_lock(&loopback->cable_lock);
693         dpcm = kzalloc(sizeof(*dpcm), GFP_KERNEL);
694         if (!dpcm) {
695                 err = -ENOMEM;
696                 goto unlock;
697         }
698         dpcm->loopback = loopback;
699         dpcm->substream = substream;
700         timer_setup(&dpcm->timer, loopback_timer_function, 0);
701 
702         cable = loopback->cables[substream->number][dev];
703         if (!cable) {
704                 cable = kzalloc(sizeof(*cable), GFP_KERNEL);
705                 if (!cable) {
706                         err = -ENOMEM;
707                         goto unlock;
708                 }
709                 spin_lock_init(&cable->lock);
710                 cable->hw = loopback_pcm_hardware;
711                 loopback->cables[substream->number][dev] = cable;
712         }
713         dpcm->cable = cable;
714 
715         snd_pcm_hw_constraint_integer(runtime, SNDRV_PCM_HW_PARAM_PERIODS);
716 
717         /* use dynamic rules based on actual runtime->hw values */
718         /* note that the default rules created in the PCM midlevel code */
719         /* are cached -> they do not reflect the actual state */
720         err = snd_pcm_hw_rule_add(runtime, 0,
721                                   SNDRV_PCM_HW_PARAM_FORMAT,
722                                   rule_format, dpcm,
723                                   SNDRV_PCM_HW_PARAM_FORMAT, -1);
724         if (err < 0)
725                 goto unlock;
726         err = snd_pcm_hw_rule_add(runtime, 0,
727                                   SNDRV_PCM_HW_PARAM_RATE,
728                                   rule_rate, dpcm,
729                                   SNDRV_PCM_HW_PARAM_RATE, -1);
730         if (err < 0)
731                 goto unlock;
732         err = snd_pcm_hw_rule_add(runtime, 0,
733                                   SNDRV_PCM_HW_PARAM_CHANNELS,
734                                   rule_channels, dpcm,
735                                   SNDRV_PCM_HW_PARAM_CHANNELS, -1);
736         if (err < 0)
737                 goto unlock;
738 
739         runtime->private_data = dpcm;
740         runtime->private_free = loopback_runtime_free;
741         if (get_notify(dpcm))
742                 runtime->hw = loopback_pcm_hardware;
743         else
744                 runtime->hw = cable->hw;
745 
746         spin_lock_irq(&cable->lock);
747         cable->streams[substream->stream] = dpcm;
748         spin_unlock_irq(&cable->lock);
749 
750  unlock:
751         if (err < 0) {
752                 free_cable(substream);
753                 kfree(dpcm);
754         }
755         mutex_unlock(&loopback->cable_lock);
756         return err;
757 }
758 
759 static int loopback_close(struct snd_pcm_substream *substream)
760 {
761         struct loopback *loopback = substream->private_data;
762         struct loopback_pcm *dpcm = substream->runtime->private_data;
763 
764         loopback_timer_stop_sync(dpcm);
765         mutex_lock(&loopback->cable_lock);
766         free_cable(substream);
767         mutex_unlock(&loopback->cable_lock);
768         return 0;
769 }
770 
771 static const struct snd_pcm_ops loopback_pcm_ops = {
772         .open =         loopback_open,
773         .close =        loopback_close,
774         .ioctl =        snd_pcm_lib_ioctl,
775         .hw_params =    loopback_hw_params,
776         .hw_free =      loopback_hw_free,
777         .prepare =      loopback_prepare,
778         .trigger =      loopback_trigger,
779         .pointer =      loopback_pointer,
780         .page =         snd_pcm_lib_get_vmalloc_page,
781 };
782 
783 static int loopback_pcm_new(struct loopback *loopback,
784                             int device, int substreams)
785 {
786         struct snd_pcm *pcm;
787         int err;
788 
789         err = snd_pcm_new(loopback->card, "Loopback PCM", device,
790                           substreams, substreams, &pcm);
791         if (err < 0)
792                 return err;
793         snd_pcm_set_ops(pcm, SNDRV_PCM_STREAM_PLAYBACK, &loopback_pcm_ops);
794         snd_pcm_set_ops(pcm, SNDRV_PCM_STREAM_CAPTURE, &loopback_pcm_ops);
795 
796         pcm->private_data = loopback;
797         pcm->info_flags = 0;
798         strcpy(pcm->name, "Loopback PCM");
799 
800         loopback->pcm[device] = pcm;
801         return 0;
802 }
803 
804 static int loopback_rate_shift_info(struct snd_kcontrol *kcontrol,   
805                                     struct snd_ctl_elem_info *uinfo) 
806 {
807         uinfo->type = SNDRV_CTL_ELEM_TYPE_INTEGER;
808         uinfo->count = 1;
809         uinfo->value.integer.min = 80000;
810         uinfo->value.integer.max = 120000;
811         uinfo->value.integer.step = 1;
812         return 0;
813 }                                  
814 
815 static int loopback_rate_shift_get(struct snd_kcontrol *kcontrol,
816                                    struct snd_ctl_elem_value *ucontrol)
817 {
818         struct loopback *loopback = snd_kcontrol_chip(kcontrol);
819         
820         mutex_lock(&loopback->cable_lock);
821         ucontrol->value.integer.value[0] =
822                 loopback->setup[kcontrol->id.subdevice]
823                                [kcontrol->id.device].rate_shift;
824         mutex_unlock(&loopback->cable_lock);
825         return 0;
826 }
827 
828 static int loopback_rate_shift_put(struct snd_kcontrol *kcontrol,
829                                    struct snd_ctl_elem_value *ucontrol)
830 {
831         struct loopback *loopback = snd_kcontrol_chip(kcontrol);
832         unsigned int val;
833         int change = 0;
834 
835         val = ucontrol->value.integer.value[0];
836         if (val < 80000)
837                 val = 80000;
838         if (val > 120000)
839                 val = 120000;   
840         mutex_lock(&loopback->cable_lock);
841         if (val != loopback->setup[kcontrol->id.subdevice]
842                                   [kcontrol->id.device].rate_shift) {
843                 loopback->setup[kcontrol->id.subdevice]
844                                [kcontrol->id.device].rate_shift = val;
845                 change = 1;
846         }
847         mutex_unlock(&loopback->cable_lock);
848         return change;
849 }
850 
851 static int loopback_notify_get(struct snd_kcontrol *kcontrol,
852                                struct snd_ctl_elem_value *ucontrol)
853 {
854         struct loopback *loopback = snd_kcontrol_chip(kcontrol);
855         
856         mutex_lock(&loopback->cable_lock);
857         ucontrol->value.integer.value[0] =
858                 loopback->setup[kcontrol->id.subdevice]
859                                [kcontrol->id.device].notify;
860         mutex_unlock(&loopback->cable_lock);
861         return 0;
862 }
863 
864 static int loopback_notify_put(struct snd_kcontrol *kcontrol,
865                                struct snd_ctl_elem_value *ucontrol)
866 {
867         struct loopback *loopback = snd_kcontrol_chip(kcontrol);
868         unsigned int val;
869         int change = 0;
870 
871         val = ucontrol->value.integer.value[0] ? 1 : 0;
872         mutex_lock(&loopback->cable_lock);
873         if (val != loopback->setup[kcontrol->id.subdevice]
874                                 [kcontrol->id.device].notify) {
875                 loopback->setup[kcontrol->id.subdevice]
876                         [kcontrol->id.device].notify = val;
877                 change = 1;
878         }
879         mutex_unlock(&loopback->cable_lock);
880         return change;
881 }
882 
883 static int loopback_active_get(struct snd_kcontrol *kcontrol,
884                                struct snd_ctl_elem_value *ucontrol)
885 {
886         struct loopback *loopback = snd_kcontrol_chip(kcontrol);
887         struct loopback_cable *cable;
888 
889         unsigned int val = 0;
890 
891         mutex_lock(&loopback->cable_lock);
892         cable = loopback->cables[kcontrol->id.subdevice][kcontrol->id.device ^ 1];
893         if (cable != NULL) {
894                 unsigned int running = cable->running ^ cable->pause;
895 
896                 val = (running & (1 << SNDRV_PCM_STREAM_PLAYBACK)) ? 1 : 0;
897         }
898         mutex_unlock(&loopback->cable_lock);
899         ucontrol->value.integer.value[0] = val;
900         return 0;
901 }
902 
903 static int loopback_format_info(struct snd_kcontrol *kcontrol,   
904                                 struct snd_ctl_elem_info *uinfo) 
905 {
906         uinfo->type = SNDRV_CTL_ELEM_TYPE_INTEGER;
907         uinfo->count = 1;
908         uinfo->value.integer.min = 0;
909         uinfo->value.integer.max = SNDRV_PCM_FORMAT_LAST;
910         uinfo->value.integer.step = 1;
911         return 0;
912 }                                  
913 
914 static int loopback_format_get(struct snd_kcontrol *kcontrol,
915                                struct snd_ctl_elem_value *ucontrol)
916 {
917         struct loopback *loopback = snd_kcontrol_chip(kcontrol);
918         
919         ucontrol->value.integer.value[0] =
920                 loopback->setup[kcontrol->id.subdevice]
921                                [kcontrol->id.device].format;
922         return 0;
923 }
924 
925 static int loopback_rate_info(struct snd_kcontrol *kcontrol,   
926                               struct snd_ctl_elem_info *uinfo) 
927 {
928         uinfo->type = SNDRV_CTL_ELEM_TYPE_INTEGER;
929         uinfo->count = 1;
930         uinfo->value.integer.min = 0;
931         uinfo->value.integer.max = 192000;
932         uinfo->value.integer.step = 1;
933         return 0;
934 }                                  
935 
936 static int loopback_rate_get(struct snd_kcontrol *kcontrol,
937                              struct snd_ctl_elem_value *ucontrol)
938 {
939         struct loopback *loopback = snd_kcontrol_chip(kcontrol);
940         
941         mutex_lock(&loopback->cable_lock);
942         ucontrol->value.integer.value[0] =
943                 loopback->setup[kcontrol->id.subdevice]
944                                [kcontrol->id.device].rate;
945         mutex_unlock(&loopback->cable_lock);
946         return 0;
947 }
948 
949 static int loopback_channels_info(struct snd_kcontrol *kcontrol,   
950                                   struct snd_ctl_elem_info *uinfo) 
951 {
952         uinfo->type = SNDRV_CTL_ELEM_TYPE_INTEGER;
953         uinfo->count = 1;
954         uinfo->value.integer.min = 1;
955         uinfo->value.integer.max = 1024;
956         uinfo->value.integer.step = 1;
957         return 0;
958 }                                  
959 
960 static int loopback_channels_get(struct snd_kcontrol *kcontrol,
961                                  struct snd_ctl_elem_value *ucontrol)
962 {
963         struct loopback *loopback = snd_kcontrol_chip(kcontrol);
964         
965         mutex_lock(&loopback->cable_lock);
966         ucontrol->value.integer.value[0] =
967                 loopback->setup[kcontrol->id.subdevice]
968                                [kcontrol->id.device].channels;
969         mutex_unlock(&loopback->cable_lock);
970         return 0;
971 }
972 
973 static struct snd_kcontrol_new loopback_controls[]  = {
974 {
975         .iface =        SNDRV_CTL_ELEM_IFACE_PCM,
976         .name =         "PCM Rate Shift 100000",
977         .info =         loopback_rate_shift_info,
978         .get =          loopback_rate_shift_get,
979         .put =          loopback_rate_shift_put,
980 },
981 {
982         .iface =        SNDRV_CTL_ELEM_IFACE_PCM,
983         .name =         "PCM Notify",
984         .info =         snd_ctl_boolean_mono_info,
985         .get =          loopback_notify_get,
986         .put =          loopback_notify_put,
987 },
988 #define ACTIVE_IDX 2
989 {
990         .access =       SNDRV_CTL_ELEM_ACCESS_READ,
991         .iface =        SNDRV_CTL_ELEM_IFACE_PCM,
992         .name =         "PCM Slave Active",
993         .info =         snd_ctl_boolean_mono_info,
994         .get =          loopback_active_get,
995 },
996 #define FORMAT_IDX 3
997 {
998         .access =       SNDRV_CTL_ELEM_ACCESS_READ,
999         .iface =        SNDRV_CTL_ELEM_IFACE_PCM,
1000         .name =         "PCM Slave Format",
1001         .info =         loopback_format_info,
1002         .get =          loopback_format_get
1003 },
1004 #define RATE_IDX 4
1005 {
1006         .access =       SNDRV_CTL_ELEM_ACCESS_READ,
1007         .iface =        SNDRV_CTL_ELEM_IFACE_PCM,
1008         .name =         "PCM Slave Rate",
1009         .info =         loopback_rate_info,
1010         .get =          loopback_rate_get
1011 },
1012 #define CHANNELS_IDX 5
1013 {
1014         .access =       SNDRV_CTL_ELEM_ACCESS_READ,
1015         .iface =        SNDRV_CTL_ELEM_IFACE_PCM,
1016         .name =         "PCM Slave Channels",
1017         .info =         loopback_channels_info,
1018         .get =          loopback_channels_get
1019 }
1020 };
1021 
1022 static int loopback_mixer_new(struct loopback *loopback, int notify)
1023 {
1024         struct snd_card *card = loopback->card;
1025         struct snd_pcm *pcm;
1026         struct snd_kcontrol *kctl;
1027         struct loopback_setup *setup;
1028         int err, dev, substr, substr_count, idx;
1029 
1030         strcpy(card->mixername, "Loopback Mixer");
1031         for (dev = 0; dev < 2; dev++) {
1032                 pcm = loopback->pcm[dev];
1033                 substr_count =
1034                     pcm->streams[SNDRV_PCM_STREAM_CAPTURE].substream_count;
1035                 for (substr = 0; substr < substr_count; substr++) {
1036                         setup = &loopback->setup[substr][dev];
1037                         setup->notify = notify;
1038                         setup->rate_shift = NO_PITCH;
1039                         setup->format = SNDRV_PCM_FORMAT_S16_LE;
1040                         setup->rate = 48000;
1041                         setup->channels = 2;
1042                         for (idx = 0; idx < ARRAY_SIZE(loopback_controls);
1043                                                                         idx++) {
1044                                 kctl = snd_ctl_new1(&loopback_controls[idx],
1045                                                     loopback);
1046                                 if (!kctl)
1047                                         return -ENOMEM;
1048                                 kctl->id.device = dev;
1049                                 kctl->id.subdevice = substr;
1050                                 switch (idx) {
1051                                 case ACTIVE_IDX:
1052                                         setup->active_id = kctl->id;
1053                                         break;
1054                                 case FORMAT_IDX:
1055                                         setup->format_id = kctl->id;
1056                                         break;
1057                                 case RATE_IDX:
1058                                         setup->rate_id = kctl->id;
1059                                         break;
1060                                 case CHANNELS_IDX:
1061                                         setup->channels_id = kctl->id;
1062                                         break;
1063                                 default:
1064                                         break;
1065                                 }
1066                                 err = snd_ctl_add(card, kctl);
1067                                 if (err < 0)
1068                                         return err;
1069                         }
1070                 }
1071         }
1072         return 0;
1073 }
1074 
1075 static void print_dpcm_info(struct snd_info_buffer *buffer,
1076                             struct loopback_pcm *dpcm,
1077                             const char *id)
1078 {
1079         snd_iprintf(buffer, "  %s\n", id);
1080         if (dpcm == NULL) {
1081                 snd_iprintf(buffer, "    inactive\n");
1082                 return;
1083         }
1084         snd_iprintf(buffer, "    buffer_size:\t%u\n", dpcm->pcm_buffer_size);
1085         snd_iprintf(buffer, "    buffer_pos:\t\t%u\n", dpcm->buf_pos);
1086         snd_iprintf(buffer, "    silent_size:\t%u\n", dpcm->silent_size);
1087         snd_iprintf(buffer, "    period_size:\t%u\n", dpcm->pcm_period_size);
1088         snd_iprintf(buffer, "    bytes_per_sec:\t%u\n", dpcm->pcm_bps);
1089         snd_iprintf(buffer, "    sample_align:\t%u\n", dpcm->pcm_salign);
1090         snd_iprintf(buffer, "    rate_shift:\t\t%u\n", dpcm->pcm_rate_shift);
1091         snd_iprintf(buffer, "    update_pending:\t%u\n",
1092                                                 dpcm->period_update_pending);
1093         snd_iprintf(buffer, "    irq_pos:\t\t%u\n", dpcm->irq_pos);
1094         snd_iprintf(buffer, "    period_frac:\t%u\n", dpcm->period_size_frac);
1095         snd_iprintf(buffer, "    last_jiffies:\t%lu (%lu)\n",
1096                                         dpcm->last_jiffies, jiffies);
1097         snd_iprintf(buffer, "    timer_expires:\t%lu\n", dpcm->timer.expires);
1098 }
1099 
1100 static void print_substream_info(struct snd_info_buffer *buffer,
1101                                  struct loopback *loopback,
1102                                  int sub,
1103                                  int num)
1104 {
1105         struct loopback_cable *cable = loopback->cables[sub][num];
1106 
1107         snd_iprintf(buffer, "Cable %i substream %i:\n", num, sub);
1108         if (cable == NULL) {
1109                 snd_iprintf(buffer, "  inactive\n");
1110                 return;
1111         }
1112         snd_iprintf(buffer, "  valid: %u\n", cable->valid);
1113         snd_iprintf(buffer, "  running: %u\n", cable->running);
1114         snd_iprintf(buffer, "  pause: %u\n", cable->pause);
1115         print_dpcm_info(buffer, cable->streams[0], "Playback");
1116         print_dpcm_info(buffer, cable->streams[1], "Capture");
1117 }
1118 
1119 static void print_cable_info(struct snd_info_entry *entry,
1120                              struct snd_info_buffer *buffer)
1121 {
1122         struct loopback *loopback = entry->private_data;
1123         int sub, num;
1124 
1125         mutex_lock(&loopback->cable_lock);
1126         num = entry->name[strlen(entry->name)-1];
1127         num = num == '' ? 0 : 1;
1128         for (sub = 0; sub < MAX_PCM_SUBSTREAMS; sub++)
1129                 print_substream_info(buffer, loopback, sub, num);
1130         mutex_unlock(&loopback->cable_lock);
1131 }
1132 
1133 static int loopback_proc_new(struct loopback *loopback, int cidx)
1134 {
1135         char name[32];
1136         struct snd_info_entry *entry;
1137         int err;
1138 
1139         snprintf(name, sizeof(name), "cable#%d", cidx);
1140         err = snd_card_proc_new(loopback->card, name, &entry);
1141         if (err < 0)
1142                 return err;
1143 
1144         snd_info_set_text_ops(entry, loopback, print_cable_info);
1145         return 0;
1146 }
1147 
1148 static int loopback_probe(struct platform_device *devptr)
1149 {
1150         struct snd_card *card;
1151         struct loopback *loopback;
1152         int dev = devptr->id;
1153         int err;
1154 
1155         err = snd_card_new(&devptr->dev, index[dev], id[dev], THIS_MODULE,
1156                            sizeof(struct loopback), &card);
1157         if (err < 0)
1158                 return err;
1159         loopback = card->private_data;
1160 
1161         if (pcm_substreams[dev] < 1)
1162                 pcm_substreams[dev] = 1;
1163         if (pcm_substreams[dev] > MAX_PCM_SUBSTREAMS)
1164                 pcm_substreams[dev] = MAX_PCM_SUBSTREAMS;
1165         
1166         loopback->card = card;
1167         mutex_init(&loopback->cable_lock);
1168 
1169         err = loopback_pcm_new(loopback, 0, pcm_substreams[dev]);
1170         if (err < 0)
1171                 goto __nodev;
1172         err = loopback_pcm_new(loopback, 1, pcm_substreams[dev]);
1173         if (err < 0)
1174                 goto __nodev;
1175         err = loopback_mixer_new(loopback, pcm_notify[dev] ? 1 : 0);
1176         if (err < 0)
1177                 goto __nodev;
1178         loopback_proc_new(loopback, 0);
1179         loopback_proc_new(loopback, 1);
1180         strcpy(card->driver, "Loopback");
1181         strcpy(card->shortname, "Loopback");
1182         sprintf(card->longname, "Loopback %i", dev + 1);
1183         err = snd_card_register(card);
1184         if (!err) {
1185                 platform_set_drvdata(devptr, card);
1186                 return 0;
1187         }
1188       __nodev:
1189         snd_card_free(card);
1190         return err;
1191 }
1192 
1193 static int loopback_remove(struct platform_device *devptr)
1194 {
1195         snd_card_free(platform_get_drvdata(devptr));
1196         return 0;
1197 }
1198 
1199 #ifdef CONFIG_PM_SLEEP
1200 static int loopback_suspend(struct device *pdev)
1201 {
1202         struct snd_card *card = dev_get_drvdata(pdev);
1203         struct loopback *loopback = card->private_data;
1204 
1205         snd_power_change_state(card, SNDRV_CTL_POWER_D3hot);
1206 
1207         snd_pcm_suspend_all(loopback->pcm[0]);
1208         snd_pcm_suspend_all(loopback->pcm[1]);
1209         return 0;
1210 }
1211         
1212 static int loopback_resume(struct device *pdev)
1213 {
1214         struct snd_card *card = dev_get_drvdata(pdev);
1215 
1216         snd_power_change_state(card, SNDRV_CTL_POWER_D0);
1217         return 0;
1218 }
1219 
1220 static SIMPLE_DEV_PM_OPS(loopback_pm, loopback_suspend, loopback_resume);
1221 #define LOOPBACK_PM_OPS &loopback_pm
1222 #else
1223 #define LOOPBACK_PM_OPS NULL
1224 #endif
1225 
1226 #define SND_LOOPBACK_DRIVER     "snd_aloop"
1227 
1228 static struct platform_driver loopback_driver = {
1229         .probe          = loopback_probe,
1230         .remove         = loopback_remove,
1231         .driver         = {
1232                 .name   = SND_LOOPBACK_DRIVER,
1233                 .pm     = LOOPBACK_PM_OPS,
1234         },
1235 };
1236 
1237 static void loopback_unregister_all(void)
1238 {
1239         int i;
1240 
1241         for (i = 0; i < ARRAY_SIZE(devices); ++i)
1242                 platform_device_unregister(devices[i]);
1243         platform_driver_unregister(&loopback_driver);
1244 }
1245 
1246 static int __init alsa_card_loopback_init(void)
1247 {
1248         int i, err, cards;
1249 
1250         err = platform_driver_register(&loopback_driver);
1251         if (err < 0)
1252                 return err;
1253 
1254 
1255         cards = 0;
1256         for (i = 0; i < SNDRV_CARDS; i++) {
1257                 struct platform_device *device;
1258                 if (!enable[i])
1259                         continue;
1260                 device = platform_device_register_simple(SND_LOOPBACK_DRIVER,
1261                                                          i, NULL, 0);
1262                 if (IS_ERR(device))
1263                         continue;
1264                 if (!platform_get_drvdata(device)) {
1265                         platform_device_unregister(device);
1266                         continue;
1267                 }
1268                 devices[i] = device;
1269                 cards++;
1270         }
1271         if (!cards) {
1272 #ifdef MODULE
1273                 printk(KERN_ERR "aloop: No loopback enabled\n");
1274 #endif
1275                 loopback_unregister_all();
1276                 return -ENODEV;
1277         }
1278         return 0;
1279 }
1280 
1281 static void __exit alsa_card_loopback_exit(void)
1282 {
1283         loopback_unregister_all();
1284 }
1285 
1286 module_init(alsa_card_loopback_init)
1287 module_exit(alsa_card_loopback_exit)
1288 

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