Version:  2.0.40 2.2.26 2.4.37 3.6 3.7 3.8 3.9 3.10 3.11 3.12 3.13 3.14 3.15 3.16 3.17 3.18 3.19 4.0 4.1 4.2

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

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