~ [ source navigation ] ~ [ diff markup ] ~ [ identifier search ] ~

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

Version: ~ [ linux-5.12-rc1 ] ~ [ linux-5.11.2 ] ~ [ linux-5.10.19 ] ~ [ linux-5.9.16 ] ~ [ linux-5.8.18 ] ~ [ linux-5.7.19 ] ~ [ linux-5.6.19 ] ~ [ linux-5.5.19 ] ~ [ linux-5.4.101 ] ~ [ linux-5.3.18 ] ~ [ linux-5.2.21 ] ~ [ linux-5.1.21 ] ~ [ linux-5.0.21 ] ~ [ linux-4.20.17 ] ~ [ linux-4.19.177 ] ~ [ linux-4.18.20 ] ~ [ linux-4.17.19 ] ~ [ linux-4.16.18 ] ~ [ linux-4.15.18 ] ~ [ linux-4.14.222 ] ~ [ linux-4.13.16 ] ~ [ linux-4.12.14 ] ~ [ linux-4.11.12 ] ~ [ linux-4.10.17 ] ~ [ linux-4.9.258 ] ~ [ linux-4.8.17 ] ~ [ linux-4.7.10 ] ~ [ linux-4.6.7 ] ~ [ linux-4.5.7 ] ~ [ linux-4.4.258 ] ~ [ linux-4.3.6 ] ~ [ linux-4.2.8 ] ~ [ linux-4.1.52 ] ~ [ linux-4.0.9 ] ~ [ linux-3.18.140 ] ~ [ linux-3.16.85 ] ~ [ linux-3.14.79 ] ~ [ linux-3.12.74 ] ~ [ linux-3.10.108 ] ~ [ linux-2.6.32.71 ] ~ [ linux-2.6.0 ] ~ [ linux-2.4.37.11 ] ~ [ unix-v6-master ] ~ [ ccs-tools-1.8.5 ] ~ [ policy-sample ] ~
Architecture: ~ [ i386 ] ~ [ alpha ] ~ [ m68k ] ~ [ mips ] ~ [ ppc ] ~ [ sparc ] ~ [ sparc64 ] ~

  1 // SPDX-License-Identifier: GPL-2.0-or-later
  2 /*
  3  *  Loopback soundcard
  4  *
  5  *  Original code:
  6  *  Copyright (c) by Jaroslav Kysela <perex@perex.cz>
  7  *
  8  *  More accurate positioning and full-duplex support:
  9  *  Copyright (c) Ahmet ─░nan <ainan at mathematik.uni-freiburg.de>
 10  *
 11  *  Major (almost complete) rewrite:
 12  *  Copyright (c) by Takashi Iwai <tiwai@suse.de>
 13  *
 14  *  A next major update in 2010 (separate timers for playback and capture):
 15  *  Copyright (c) Jaroslav Kysela <perex@perex.cz>
 16  */
 17 
 18 #include <linux/init.h>
 19 #include <linux/jiffies.h>
 20 #include <linux/slab.h>
 21 #include <linux/time.h>
 22 #include <linux/wait.h>
 23 #include <linux/module.h>
 24 #include <linux/platform_device.h>
 25 #include <sound/core.h>
 26 #include <sound/control.h>
 27 #include <sound/pcm.h>
 28 #include <sound/pcm_params.h>
 29 #include <sound/info.h>
 30 #include <sound/initval.h>
 31 
 32 MODULE_AUTHOR("Jaroslav Kysela <perex@perex.cz>");
 33 MODULE_DESCRIPTION("A loopback soundcard");
 34 MODULE_LICENSE("GPL");
 35 MODULE_SUPPORTED_DEVICE("{{ALSA,Loopback soundcard}}");
 36 
 37 #define MAX_PCM_SUBSTREAMS      8
 38 
 39 static int index[SNDRV_CARDS] = SNDRV_DEFAULT_IDX;      /* Index 0-MAX */
 40 static char *id[SNDRV_CARDS] = SNDRV_DEFAULT_STR;       /* ID for this card */
 41 static bool enable[SNDRV_CARDS] = {1, [1 ... (SNDRV_CARDS - 1)] = 0};
 42 static int pcm_substreams[SNDRV_CARDS] = {[0 ... (SNDRV_CARDS - 1)] = 8};
 43 static int pcm_notify[SNDRV_CARDS];
 44 
 45 module_param_array(index, int, NULL, 0444);
 46 MODULE_PARM_DESC(index, "Index value for loopback soundcard.");
 47 module_param_array(id, charp, NULL, 0444);
 48 MODULE_PARM_DESC(id, "ID string for loopback soundcard.");
 49 module_param_array(enable, bool, NULL, 0444);
 50 MODULE_PARM_DESC(enable, "Enable this loopback soundcard.");
 51 module_param_array(pcm_substreams, int, NULL, 0444);
 52 MODULE_PARM_DESC(pcm_substreams, "PCM substreams # (1-8) for loopback driver.");
 53 module_param_array(pcm_notify, int, NULL, 0444);
 54 MODULE_PARM_DESC(pcm_notify, "Break capture when PCM format/rate/channels changes.");
 55 
 56 #define NO_PITCH 100000
 57 
 58 struct loopback_pcm;
 59 
 60 struct loopback_cable {
 61         spinlock_t lock;
 62         struct loopback_pcm *streams[2];
 63         struct snd_pcm_hardware hw;
 64         /* flags */
 65         unsigned int valid;
 66         unsigned int running;
 67         unsigned int pause;
 68 };
 69 
 70 struct loopback_setup {
 71         unsigned int notify: 1;
 72         unsigned int rate_shift;
 73         unsigned int format;
 74         unsigned int rate;
 75         unsigned int channels;
 76         struct snd_ctl_elem_id active_id;
 77         struct snd_ctl_elem_id format_id;
 78         struct snd_ctl_elem_id rate_id;
 79         struct snd_ctl_elem_id channels_id;
 80 };
 81 
 82 struct loopback {
 83         struct snd_card *card;
 84         struct mutex cable_lock;
 85         struct loopback_cable *cables[MAX_PCM_SUBSTREAMS][2];
 86         struct snd_pcm *pcm[2];
 87         struct loopback_setup setup[MAX_PCM_SUBSTREAMS][2];
 88 };
 89 
 90 struct loopback_pcm {
 91         struct loopback *loopback;
 92         struct snd_pcm_substream *substream;
 93         struct loopback_cable *cable;
 94         unsigned int pcm_buffer_size;
 95         unsigned int buf_pos;   /* position in buffer */
 96         unsigned int silent_size;
 97         /* PCM parameters */
 98         unsigned int pcm_period_size;
 99         unsigned int pcm_bps;           /* bytes per second */
100         unsigned int pcm_salign;        /* bytes per sample * channels */
101         unsigned int pcm_rate_shift;    /* rate shift value */
102         /* flags */
103         unsigned int period_update_pending :1;
104         /* timer stuff */
105         unsigned int irq_pos;           /* fractional IRQ position */
106         unsigned int period_size_frac;
107         unsigned int last_drift;
108         unsigned long last_jiffies;
109         struct timer_list timer;
110 };
111 
112 static struct platform_device *devices[SNDRV_CARDS];
113 
114 static inline unsigned int byte_pos(struct loopback_pcm *dpcm, unsigned int x)
115 {
116         if (dpcm->pcm_rate_shift == NO_PITCH) {
117                 x /= HZ;
118         } else {
119                 x = div_u64(NO_PITCH * (unsigned long long)x,
120                             HZ * (unsigned long long)dpcm->pcm_rate_shift);
121         }
122         return x - (x % dpcm->pcm_salign);
123 }
124 
125 static inline unsigned int frac_pos(struct loopback_pcm *dpcm, unsigned int x)
126 {
127         if (dpcm->pcm_rate_shift == NO_PITCH) { /* no pitch */
128                 return x * HZ;
129         } else {
130                 x = div_u64(dpcm->pcm_rate_shift * (unsigned long long)x * HZ,
131                             NO_PITCH);
132         }
133         return x;
134 }
135 
136 static inline struct loopback_setup *get_setup(struct loopback_pcm *dpcm)
137 {
138         int device = dpcm->substream->pstr->pcm->device;
139         
140         if (dpcm->substream->stream == SNDRV_PCM_STREAM_PLAYBACK)
141                 device ^= 1;
142         return &dpcm->loopback->setup[dpcm->substream->number][device];
143 }
144 
145 static inline unsigned int get_notify(struct loopback_pcm *dpcm)
146 {
147         return get_setup(dpcm)->notify;
148 }
149 
150 static inline unsigned int get_rate_shift(struct loopback_pcm *dpcm)
151 {
152         return get_setup(dpcm)->rate_shift;
153 }
154 
155 /* call in cable->lock */
156 static void loopback_timer_start(struct loopback_pcm *dpcm)
157 {
158         unsigned long tick;
159         unsigned int rate_shift = get_rate_shift(dpcm);
160 
161         if (rate_shift != dpcm->pcm_rate_shift) {
162                 dpcm->pcm_rate_shift = rate_shift;
163                 dpcm->period_size_frac = frac_pos(dpcm, dpcm->pcm_period_size);
164         }
165         if (dpcm->period_size_frac <= dpcm->irq_pos) {
166                 dpcm->irq_pos %= dpcm->period_size_frac;
167                 dpcm->period_update_pending = 1;
168         }
169         tick = dpcm->period_size_frac - dpcm->irq_pos;
170         tick = (tick + dpcm->pcm_bps - 1) / dpcm->pcm_bps;
171         mod_timer(&dpcm->timer, jiffies + tick);
172 }
173 
174 /* call in cable->lock */
175 static inline void loopback_timer_stop(struct loopback_pcm *dpcm)
176 {
177         del_timer(&dpcm->timer);
178         dpcm->timer.expires = 0;
179 }
180 
181 static inline void loopback_timer_stop_sync(struct loopback_pcm *dpcm)
182 {
183         del_timer_sync(&dpcm->timer);
184 }
185 
186 #define CABLE_VALID_PLAYBACK    (1 << SNDRV_PCM_STREAM_PLAYBACK)
187 #define CABLE_VALID_CAPTURE     (1 << SNDRV_PCM_STREAM_CAPTURE)
188 #define CABLE_VALID_BOTH        (CABLE_VALID_PLAYBACK|CABLE_VALID_CAPTURE)
189 
190 static int loopback_check_format(struct loopback_cable *cable, int stream)
191 {
192         struct snd_pcm_runtime *runtime, *cruntime;
193         struct loopback_setup *setup;
194         struct snd_card *card;
195         int check;
196 
197         if (cable->valid != CABLE_VALID_BOTH) {
198                 if (stream == SNDRV_PCM_STREAM_PLAYBACK)
199                         goto __notify;
200                 return 0;
201         }
202         runtime = cable->streams[SNDRV_PCM_STREAM_PLAYBACK]->
203                                                         substream->runtime;
204         cruntime = cable->streams[SNDRV_PCM_STREAM_CAPTURE]->
205                                                         substream->runtime;
206         check = runtime->format != cruntime->format ||
207                 runtime->rate != cruntime->rate ||
208                 runtime->channels != cruntime->channels;
209         if (!check)
210                 return 0;
211         if (stream == SNDRV_PCM_STREAM_CAPTURE) {
212                 return -EIO;
213         } else {
214                 snd_pcm_stop(cable->streams[SNDRV_PCM_STREAM_CAPTURE]->
215                                         substream, SNDRV_PCM_STATE_DRAINING);
216               __notify:
217                 runtime = cable->streams[SNDRV_PCM_STREAM_PLAYBACK]->
218                                                         substream->runtime;
219                 setup = get_setup(cable->streams[SNDRV_PCM_STREAM_PLAYBACK]);
220                 card = cable->streams[SNDRV_PCM_STREAM_PLAYBACK]->loopback->card;
221                 if (setup->format != runtime->format) {
222                         snd_ctl_notify(card, SNDRV_CTL_EVENT_MASK_VALUE,
223                                                         &setup->format_id);
224                         setup->format = runtime->format;
225                 }
226                 if (setup->rate != runtime->rate) {
227                         snd_ctl_notify(card, SNDRV_CTL_EVENT_MASK_VALUE,
228                                                         &setup->rate_id);
229                         setup->rate = runtime->rate;
230                 }
231                 if (setup->channels != runtime->channels) {
232                         snd_ctl_notify(card, SNDRV_CTL_EVENT_MASK_VALUE,
233                                                         &setup->channels_id);
234                         setup->channels = runtime->channels;
235                 }
236         }
237         return 0;
238 }
239 
240 static void loopback_active_notify(struct loopback_pcm *dpcm)
241 {
242         snd_ctl_notify(dpcm->loopback->card,
243                        SNDRV_CTL_EVENT_MASK_VALUE,
244                        &get_setup(dpcm)->active_id);
245 }
246 
247 static int loopback_trigger(struct snd_pcm_substream *substream, int cmd)
248 {
249         struct snd_pcm_runtime *runtime = substream->runtime;
250         struct loopback_pcm *dpcm = runtime->private_data;
251         struct loopback_cable *cable = dpcm->cable;
252         int err, stream = 1 << substream->stream;
253 
254         switch (cmd) {
255         case SNDRV_PCM_TRIGGER_START:
256                 err = loopback_check_format(cable, substream->stream);
257                 if (err < 0)
258                         return err;
259                 dpcm->last_jiffies = jiffies;
260                 dpcm->pcm_rate_shift = 0;
261                 dpcm->last_drift = 0;
262                 spin_lock(&cable->lock);        
263                 cable->running |= stream;
264                 cable->pause &= ~stream;
265                 loopback_timer_start(dpcm);
266                 spin_unlock(&cable->lock);
267                 if (substream->stream == SNDRV_PCM_STREAM_PLAYBACK)
268                         loopback_active_notify(dpcm);
269                 break;
270         case SNDRV_PCM_TRIGGER_STOP:
271                 spin_lock(&cable->lock);        
272                 cable->running &= ~stream;
273                 cable->pause &= ~stream;
274                 loopback_timer_stop(dpcm);
275                 spin_unlock(&cable->lock);
276                 if (substream->stream == SNDRV_PCM_STREAM_PLAYBACK)
277                         loopback_active_notify(dpcm);
278                 break;
279         case SNDRV_PCM_TRIGGER_PAUSE_PUSH:
280         case SNDRV_PCM_TRIGGER_SUSPEND:
281                 spin_lock(&cable->lock);        
282                 cable->pause |= stream;
283                 loopback_timer_stop(dpcm);
284                 spin_unlock(&cable->lock);
285                 if (substream->stream == SNDRV_PCM_STREAM_PLAYBACK)
286                         loopback_active_notify(dpcm);
287                 break;
288         case SNDRV_PCM_TRIGGER_PAUSE_RELEASE:
289         case SNDRV_PCM_TRIGGER_RESUME:
290                 spin_lock(&cable->lock);
291                 dpcm->last_jiffies = jiffies;
292                 cable->pause &= ~stream;
293                 loopback_timer_start(dpcm);
294                 spin_unlock(&cable->lock);
295                 if (substream->stream == SNDRV_PCM_STREAM_PLAYBACK)
296                         loopback_active_notify(dpcm);
297                 break;
298         default:
299                 return -EINVAL;
300         }
301         return 0;
302 }
303 
304 static void params_change(struct snd_pcm_substream *substream)
305 {
306         struct snd_pcm_runtime *runtime = substream->runtime;
307         struct loopback_pcm *dpcm = runtime->private_data;
308         struct loopback_cable *cable = dpcm->cable;
309 
310         cable->hw.formats = pcm_format_to_bits(runtime->format);
311         cable->hw.rate_min = runtime->rate;
312         cable->hw.rate_max = runtime->rate;
313         cable->hw.channels_min = runtime->channels;
314         cable->hw.channels_max = runtime->channels;
315 }
316 
317 static int loopback_prepare(struct snd_pcm_substream *substream)
318 {
319         struct snd_pcm_runtime *runtime = substream->runtime;
320         struct loopback_pcm *dpcm = runtime->private_data;
321         struct loopback_cable *cable = dpcm->cable;
322         int bps, salign;
323 
324         loopback_timer_stop_sync(dpcm);
325 
326         salign = (snd_pcm_format_physical_width(runtime->format) *
327                                                 runtime->channels) / 8;
328         bps = salign * runtime->rate;
329         if (bps <= 0 || salign <= 0)
330                 return -EINVAL;
331 
332         dpcm->buf_pos = 0;
333         dpcm->pcm_buffer_size = frames_to_bytes(runtime, runtime->buffer_size);
334         if (substream->stream == SNDRV_PCM_STREAM_CAPTURE) {
335                 /* clear capture buffer */
336                 dpcm->silent_size = dpcm->pcm_buffer_size;
337                 snd_pcm_format_set_silence(runtime->format, runtime->dma_area,
338                                            runtime->buffer_size * runtime->channels);
339         }
340 
341         dpcm->irq_pos = 0;
342         dpcm->period_update_pending = 0;
343         dpcm->pcm_bps = bps;
344         dpcm->pcm_salign = salign;
345         dpcm->pcm_period_size = frames_to_bytes(runtime, runtime->period_size);
346 
347         mutex_lock(&dpcm->loopback->cable_lock);
348         if (!(cable->valid & ~(1 << substream->stream)) ||
349             (get_setup(dpcm)->notify &&
350              substream->stream == SNDRV_PCM_STREAM_PLAYBACK))
351                 params_change(substream);
352         cable->valid |= 1 << substream->stream;
353         mutex_unlock(&dpcm->loopback->cable_lock);
354 
355         return 0;
356 }
357 
358 static void clear_capture_buf(struct loopback_pcm *dpcm, unsigned int bytes)
359 {
360         struct snd_pcm_runtime *runtime = dpcm->substream->runtime;
361         char *dst = runtime->dma_area;
362         unsigned int dst_off = dpcm->buf_pos;
363 
364         if (dpcm->silent_size >= dpcm->pcm_buffer_size)
365                 return;
366         if (dpcm->silent_size + bytes > dpcm->pcm_buffer_size)
367                 bytes = dpcm->pcm_buffer_size - dpcm->silent_size;
368 
369         for (;;) {
370                 unsigned int size = bytes;
371                 if (dst_off + size > dpcm->pcm_buffer_size)
372                         size = dpcm->pcm_buffer_size - dst_off;
373                 snd_pcm_format_set_silence(runtime->format, dst + dst_off,
374                                            bytes_to_frames(runtime, size) *
375                                                 runtime->channels);
376                 dpcm->silent_size += size;
377                 bytes -= size;
378                 if (!bytes)
379                         break;
380                 dst_off = 0;
381         }
382 }
383 
384 static void copy_play_buf(struct loopback_pcm *play,
385                           struct loopback_pcm *capt,
386                           unsigned int bytes)
387 {
388         struct snd_pcm_runtime *runtime = play->substream->runtime;
389         char *src = runtime->dma_area;
390         char *dst = capt->substream->runtime->dma_area;
391         unsigned int src_off = play->buf_pos;
392         unsigned int dst_off = capt->buf_pos;
393         unsigned int clear_bytes = 0;
394 
395         /* check if playback is draining, trim the capture copy size
396          * when our pointer is at the end of playback ring buffer */
397         if (runtime->status->state == SNDRV_PCM_STATE_DRAINING &&
398             snd_pcm_playback_hw_avail(runtime) < runtime->buffer_size) { 
399                 snd_pcm_uframes_t appl_ptr, appl_ptr1, diff;
400                 appl_ptr = appl_ptr1 = runtime->control->appl_ptr;
401                 appl_ptr1 -= appl_ptr1 % runtime->buffer_size;
402                 appl_ptr1 += play->buf_pos / play->pcm_salign;
403                 if (appl_ptr < appl_ptr1)
404                         appl_ptr1 -= runtime->buffer_size;
405                 diff = (appl_ptr - appl_ptr1) * play->pcm_salign;
406                 if (diff < bytes) {
407                         clear_bytes = bytes - diff;
408                         bytes = diff;
409                 }
410         }
411 
412         for (;;) {
413                 unsigned int size = bytes;
414                 if (src_off + size > play->pcm_buffer_size)
415                         size = play->pcm_buffer_size - src_off;
416                 if (dst_off + size > capt->pcm_buffer_size)
417                         size = capt->pcm_buffer_size - dst_off;
418                 memcpy(dst + dst_off, src + src_off, size);
419                 capt->silent_size = 0;
420                 bytes -= size;
421                 if (!bytes)
422                         break;
423                 src_off = (src_off + size) % play->pcm_buffer_size;
424                 dst_off = (dst_off + size) % capt->pcm_buffer_size;
425         }
426 
427         if (clear_bytes > 0) {
428                 clear_capture_buf(capt, clear_bytes);
429                 capt->silent_size = 0;
430         }
431 }
432 
433 static inline unsigned int bytepos_delta(struct loopback_pcm *dpcm,
434                                          unsigned int jiffies_delta)
435 {
436         unsigned long last_pos;
437         unsigned int delta;
438 
439         last_pos = byte_pos(dpcm, dpcm->irq_pos);
440         dpcm->irq_pos += jiffies_delta * dpcm->pcm_bps;
441         delta = byte_pos(dpcm, dpcm->irq_pos) - last_pos;
442         if (delta >= dpcm->last_drift)
443                 delta -= dpcm->last_drift;
444         dpcm->last_drift = 0;
445         if (dpcm->irq_pos >= dpcm->period_size_frac) {
446                 dpcm->irq_pos %= dpcm->period_size_frac;
447                 dpcm->period_update_pending = 1;
448         }
449         return delta;
450 }
451 
452 static inline void bytepos_finish(struct loopback_pcm *dpcm,
453                                   unsigned int delta)
454 {
455         dpcm->buf_pos += delta;
456         dpcm->buf_pos %= dpcm->pcm_buffer_size;
457 }
458 
459 /* call in cable->lock */
460 static unsigned int loopback_pos_update(struct loopback_cable *cable)
461 {
462         struct loopback_pcm *dpcm_play =
463                         cable->streams[SNDRV_PCM_STREAM_PLAYBACK];
464         struct loopback_pcm *dpcm_capt =
465                         cable->streams[SNDRV_PCM_STREAM_CAPTURE];
466         unsigned long delta_play = 0, delta_capt = 0;
467         unsigned int running, count1, count2;
468 
469         running = cable->running ^ cable->pause;
470         if (running & (1 << SNDRV_PCM_STREAM_PLAYBACK)) {
471                 delta_play = jiffies - dpcm_play->last_jiffies;
472                 dpcm_play->last_jiffies += delta_play;
473         }
474 
475         if (running & (1 << SNDRV_PCM_STREAM_CAPTURE)) {
476                 delta_capt = jiffies - dpcm_capt->last_jiffies;
477                 dpcm_capt->last_jiffies += delta_capt;
478         }
479 
480         if (delta_play == 0 && delta_capt == 0)
481                 goto unlock;
482                 
483         if (delta_play > delta_capt) {
484                 count1 = bytepos_delta(dpcm_play, delta_play - delta_capt);
485                 bytepos_finish(dpcm_play, count1);
486                 delta_play = delta_capt;
487         } else if (delta_play < delta_capt) {
488                 count1 = bytepos_delta(dpcm_capt, delta_capt - delta_play);
489                 clear_capture_buf(dpcm_capt, count1);
490                 bytepos_finish(dpcm_capt, count1);
491                 delta_capt = delta_play;
492         }
493 
494         if (delta_play == 0 && delta_capt == 0)
495                 goto unlock;
496 
497         /* note delta_capt == delta_play at this moment */
498         count1 = bytepos_delta(dpcm_play, delta_play);
499         count2 = bytepos_delta(dpcm_capt, delta_capt);
500         if (count1 < count2) {
501                 dpcm_capt->last_drift = count2 - count1;
502                 count1 = count2;
503         } else if (count1 > count2) {
504                 dpcm_play->last_drift = count1 - count2;
505         }
506         copy_play_buf(dpcm_play, dpcm_capt, count1);
507         bytepos_finish(dpcm_play, count1);
508         bytepos_finish(dpcm_capt, count1);
509  unlock:
510         return running;
511 }
512 
513 static void loopback_timer_function(struct timer_list *t)
514 {
515         struct loopback_pcm *dpcm = from_timer(dpcm, t, timer);
516         unsigned long flags;
517 
518         spin_lock_irqsave(&dpcm->cable->lock, flags);
519         if (loopback_pos_update(dpcm->cable) & (1 << dpcm->substream->stream)) {
520                 loopback_timer_start(dpcm);
521                 if (dpcm->period_update_pending) {
522                         dpcm->period_update_pending = 0;
523                         spin_unlock_irqrestore(&dpcm->cable->lock, flags);
524                         /* need to unlock before calling below */
525                         snd_pcm_period_elapsed(dpcm->substream);
526                         return;
527                 }
528         }
529         spin_unlock_irqrestore(&dpcm->cable->lock, flags);
530 }
531 
532 static snd_pcm_uframes_t loopback_pointer(struct snd_pcm_substream *substream)
533 {
534         struct snd_pcm_runtime *runtime = substream->runtime;
535         struct loopback_pcm *dpcm = runtime->private_data;
536         snd_pcm_uframes_t pos;
537 
538         spin_lock(&dpcm->cable->lock);
539         loopback_pos_update(dpcm->cable);
540         pos = dpcm->buf_pos;
541         spin_unlock(&dpcm->cable->lock);
542         return bytes_to_frames(runtime, pos);
543 }
544 
545 static const struct snd_pcm_hardware loopback_pcm_hardware =
546 {
547         .info =         (SNDRV_PCM_INFO_INTERLEAVED | SNDRV_PCM_INFO_MMAP |
548                          SNDRV_PCM_INFO_MMAP_VALID | SNDRV_PCM_INFO_PAUSE |
549                          SNDRV_PCM_INFO_RESUME),
550         .formats =      (SNDRV_PCM_FMTBIT_S16_LE | SNDRV_PCM_FMTBIT_S16_BE |
551                          SNDRV_PCM_FMTBIT_S24_LE | SNDRV_PCM_FMTBIT_S24_BE |
552                          SNDRV_PCM_FMTBIT_S24_3LE | SNDRV_PCM_FMTBIT_S24_3BE |
553                          SNDRV_PCM_FMTBIT_S32_LE | SNDRV_PCM_FMTBIT_S32_BE |
554                          SNDRV_PCM_FMTBIT_FLOAT_LE | SNDRV_PCM_FMTBIT_FLOAT_BE),
555         .rates =        SNDRV_PCM_RATE_CONTINUOUS | SNDRV_PCM_RATE_8000_192000,
556         .rate_min =             8000,
557         .rate_max =             192000,
558         .channels_min =         1,
559         .channels_max =         32,
560         .buffer_bytes_max =     2 * 1024 * 1024,
561         .period_bytes_min =     64,
562         /* note check overflow in frac_pos() using pcm_rate_shift before
563            changing period_bytes_max value */
564         .period_bytes_max =     1024 * 1024,
565         .periods_min =          1,
566         .periods_max =          1024,
567         .fifo_size =            0,
568 };
569 
570 static void loopback_runtime_free(struct snd_pcm_runtime *runtime)
571 {
572         struct loopback_pcm *dpcm = runtime->private_data;
573         kfree(dpcm);
574 }
575 
576 static int loopback_hw_params(struct snd_pcm_substream *substream,
577                               struct snd_pcm_hw_params *params)
578 {
579         return snd_pcm_lib_alloc_vmalloc_buffer(substream,
580                                                 params_buffer_bytes(params));
581 }
582 
583 static int loopback_hw_free(struct snd_pcm_substream *substream)
584 {
585         struct snd_pcm_runtime *runtime = substream->runtime;
586         struct loopback_pcm *dpcm = runtime->private_data;
587         struct loopback_cable *cable = dpcm->cable;
588 
589         mutex_lock(&dpcm->loopback->cable_lock);
590         cable->valid &= ~(1 << substream->stream);
591         mutex_unlock(&dpcm->loopback->cable_lock);
592         return snd_pcm_lib_free_vmalloc_buffer(substream);
593 }
594 
595 static unsigned int get_cable_index(struct snd_pcm_substream *substream)
596 {
597         if (!substream->pcm->device)
598                 return substream->stream;
599         else
600                 return !substream->stream;
601 }
602 
603 static int rule_format(struct snd_pcm_hw_params *params,
604                        struct snd_pcm_hw_rule *rule)
605 {
606         struct loopback_pcm *dpcm = rule->private;
607         struct loopback_cable *cable = dpcm->cable;
608         struct snd_mask m;
609 
610         snd_mask_none(&m);
611         mutex_lock(&dpcm->loopback->cable_lock);
612         m.bits[0] = (u_int32_t)cable->hw.formats;
613         m.bits[1] = (u_int32_t)(cable->hw.formats >> 32);
614         mutex_unlock(&dpcm->loopback->cable_lock);
615         return snd_mask_refine(hw_param_mask(params, rule->var), &m);
616 }
617 
618 static int rule_rate(struct snd_pcm_hw_params *params,
619                      struct snd_pcm_hw_rule *rule)
620 {
621         struct loopback_pcm *dpcm = rule->private;
622         struct loopback_cable *cable = dpcm->cable;
623         struct snd_interval t;
624 
625         mutex_lock(&dpcm->loopback->cable_lock);
626         t.min = cable->hw.rate_min;
627         t.max = cable->hw.rate_max;
628         mutex_unlock(&dpcm->loopback->cable_lock);
629         t.openmin = t.openmax = 0;
630         t.integer = 0;
631         return snd_interval_refine(hw_param_interval(params, rule->var), &t);
632 }
633 
634 static int rule_channels(struct snd_pcm_hw_params *params,
635                          struct snd_pcm_hw_rule *rule)
636 {
637         struct loopback_pcm *dpcm = rule->private;
638         struct loopback_cable *cable = dpcm->cable;
639         struct snd_interval t;
640 
641         mutex_lock(&dpcm->loopback->cable_lock);
642         t.min = cable->hw.channels_min;
643         t.max = cable->hw.channels_max;
644         mutex_unlock(&dpcm->loopback->cable_lock);
645         t.openmin = t.openmax = 0;
646         t.integer = 0;
647         return snd_interval_refine(hw_param_interval(params, rule->var), &t);
648 }
649 
650 static void free_cable(struct snd_pcm_substream *substream)
651 {
652         struct loopback *loopback = substream->private_data;
653         int dev = get_cable_index(substream);
654         struct loopback_cable *cable;
655 
656         cable = loopback->cables[substream->number][dev];
657         if (!cable)
658                 return;
659         if (cable->streams[!substream->stream]) {
660                 /* other stream is still alive */
661                 spin_lock_irq(&cable->lock);
662                 cable->streams[substream->stream] = NULL;
663                 spin_unlock_irq(&cable->lock);
664         } else {
665                 /* free the cable */
666                 loopback->cables[substream->number][dev] = NULL;
667                 kfree(cable);
668         }
669 }
670 
671 static int loopback_open(struct snd_pcm_substream *substream)
672 {
673         struct snd_pcm_runtime *runtime = substream->runtime;
674         struct loopback *loopback = substream->private_data;
675         struct loopback_pcm *dpcm;
676         struct loopback_cable *cable = NULL;
677         int err = 0;
678         int dev = get_cable_index(substream);
679 
680         mutex_lock(&loopback->cable_lock);
681         dpcm = kzalloc(sizeof(*dpcm), GFP_KERNEL);
682         if (!dpcm) {
683                 err = -ENOMEM;
684                 goto unlock;
685         }
686         dpcm->loopback = loopback;
687         dpcm->substream = substream;
688         timer_setup(&dpcm->timer, loopback_timer_function, 0);
689 
690         cable = loopback->cables[substream->number][dev];
691         if (!cable) {
692                 cable = kzalloc(sizeof(*cable), GFP_KERNEL);
693                 if (!cable) {
694                         err = -ENOMEM;
695                         goto unlock;
696                 }
697                 spin_lock_init(&cable->lock);
698                 cable->hw = loopback_pcm_hardware;
699                 loopback->cables[substream->number][dev] = cable;
700         }
701         dpcm->cable = cable;
702 
703         snd_pcm_hw_constraint_integer(runtime, SNDRV_PCM_HW_PARAM_PERIODS);
704 
705         /* use dynamic rules based on actual runtime->hw values */
706         /* note that the default rules created in the PCM midlevel code */
707         /* are cached -> they do not reflect the actual state */
708         err = snd_pcm_hw_rule_add(runtime, 0,
709                                   SNDRV_PCM_HW_PARAM_FORMAT,
710                                   rule_format, dpcm,
711                                   SNDRV_PCM_HW_PARAM_FORMAT, -1);
712         if (err < 0)
713                 goto unlock;
714         err = snd_pcm_hw_rule_add(runtime, 0,
715                                   SNDRV_PCM_HW_PARAM_RATE,
716                                   rule_rate, dpcm,
717                                   SNDRV_PCM_HW_PARAM_RATE, -1);
718         if (err < 0)
719                 goto unlock;
720         err = snd_pcm_hw_rule_add(runtime, 0,
721                                   SNDRV_PCM_HW_PARAM_CHANNELS,
722                                   rule_channels, dpcm,
723                                   SNDRV_PCM_HW_PARAM_CHANNELS, -1);
724         if (err < 0)
725                 goto unlock;
726 
727         runtime->private_data = dpcm;
728         runtime->private_free = loopback_runtime_free;
729         if (get_notify(dpcm))
730                 runtime->hw = loopback_pcm_hardware;
731         else
732                 runtime->hw = cable->hw;
733 
734         spin_lock_irq(&cable->lock);
735         cable->streams[substream->stream] = dpcm;
736         spin_unlock_irq(&cable->lock);
737 
738  unlock:
739         if (err < 0) {
740                 free_cable(substream);
741                 kfree(dpcm);
742         }
743         mutex_unlock(&loopback->cable_lock);
744         return err;
745 }
746 
747 static int loopback_close(struct snd_pcm_substream *substream)
748 {
749         struct loopback *loopback = substream->private_data;
750         struct loopback_pcm *dpcm = substream->runtime->private_data;
751 
752         loopback_timer_stop_sync(dpcm);
753         mutex_lock(&loopback->cable_lock);
754         free_cable(substream);
755         mutex_unlock(&loopback->cable_lock);
756         return 0;
757 }
758 
759 static const struct snd_pcm_ops loopback_pcm_ops = {
760         .open =         loopback_open,
761         .close =        loopback_close,
762         .ioctl =        snd_pcm_lib_ioctl,
763         .hw_params =    loopback_hw_params,
764         .hw_free =      loopback_hw_free,
765         .prepare =      loopback_prepare,
766         .trigger =      loopback_trigger,
767         .pointer =      loopback_pointer,
768         .page =         snd_pcm_lib_get_vmalloc_page,
769 };
770 
771 static int loopback_pcm_new(struct loopback *loopback,
772                             int device, int substreams)
773 {
774         struct snd_pcm *pcm;
775         int err;
776 
777         err = snd_pcm_new(loopback->card, "Loopback PCM", device,
778                           substreams, substreams, &pcm);
779         if (err < 0)
780                 return err;
781         snd_pcm_set_ops(pcm, SNDRV_PCM_STREAM_PLAYBACK, &loopback_pcm_ops);
782         snd_pcm_set_ops(pcm, SNDRV_PCM_STREAM_CAPTURE, &loopback_pcm_ops);
783 
784         pcm->private_data = loopback;
785         pcm->info_flags = 0;
786         strcpy(pcm->name, "Loopback PCM");
787 
788         loopback->pcm[device] = pcm;
789         return 0;
790 }
791 
792 static int loopback_rate_shift_info(struct snd_kcontrol *kcontrol,   
793                                     struct snd_ctl_elem_info *uinfo) 
794 {
795         uinfo->type = SNDRV_CTL_ELEM_TYPE_INTEGER;
796         uinfo->count = 1;
797         uinfo->value.integer.min = 80000;
798         uinfo->value.integer.max = 120000;
799         uinfo->value.integer.step = 1;
800         return 0;
801 }                                  
802 
803 static int loopback_rate_shift_get(struct snd_kcontrol *kcontrol,
804                                    struct snd_ctl_elem_value *ucontrol)
805 {
806         struct loopback *loopback = snd_kcontrol_chip(kcontrol);
807         
808         mutex_lock(&loopback->cable_lock);
809         ucontrol->value.integer.value[0] =
810                 loopback->setup[kcontrol->id.subdevice]
811                                [kcontrol->id.device].rate_shift;
812         mutex_unlock(&loopback->cable_lock);
813         return 0;
814 }
815 
816 static int loopback_rate_shift_put(struct snd_kcontrol *kcontrol,
817                                    struct snd_ctl_elem_value *ucontrol)
818 {
819         struct loopback *loopback = snd_kcontrol_chip(kcontrol);
820         unsigned int val;
821         int change = 0;
822 
823         val = ucontrol->value.integer.value[0];
824         if (val < 80000)
825                 val = 80000;
826         if (val > 120000)
827                 val = 120000;   
828         mutex_lock(&loopback->cable_lock);
829         if (val != loopback->setup[kcontrol->id.subdevice]
830                                   [kcontrol->id.device].rate_shift) {
831                 loopback->setup[kcontrol->id.subdevice]
832                                [kcontrol->id.device].rate_shift = val;
833                 change = 1;
834         }
835         mutex_unlock(&loopback->cable_lock);
836         return change;
837 }
838 
839 static int loopback_notify_get(struct snd_kcontrol *kcontrol,
840                                struct snd_ctl_elem_value *ucontrol)
841 {
842         struct loopback *loopback = snd_kcontrol_chip(kcontrol);
843         
844         mutex_lock(&loopback->cable_lock);
845         ucontrol->value.integer.value[0] =
846                 loopback->setup[kcontrol->id.subdevice]
847                                [kcontrol->id.device].notify;
848         mutex_unlock(&loopback->cable_lock);
849         return 0;
850 }
851 
852 static int loopback_notify_put(struct snd_kcontrol *kcontrol,
853                                struct snd_ctl_elem_value *ucontrol)
854 {
855         struct loopback *loopback = snd_kcontrol_chip(kcontrol);
856         unsigned int val;
857         int change = 0;
858 
859         val = ucontrol->value.integer.value[0] ? 1 : 0;
860         mutex_lock(&loopback->cable_lock);
861         if (val != loopback->setup[kcontrol->id.subdevice]
862                                 [kcontrol->id.device].notify) {
863                 loopback->setup[kcontrol->id.subdevice]
864                         [kcontrol->id.device].notify = val;
865                 change = 1;
866         }
867         mutex_unlock(&loopback->cable_lock);
868         return change;
869 }
870 
871 static int loopback_active_get(struct snd_kcontrol *kcontrol,
872                                struct snd_ctl_elem_value *ucontrol)
873 {
874         struct loopback *loopback = snd_kcontrol_chip(kcontrol);
875         struct loopback_cable *cable;
876 
877         unsigned int val = 0;
878 
879         mutex_lock(&loopback->cable_lock);
880         cable = loopback->cables[kcontrol->id.subdevice][kcontrol->id.device ^ 1];
881         if (cable != NULL) {
882                 unsigned int running = cable->running ^ cable->pause;
883 
884                 val = (running & (1 << SNDRV_PCM_STREAM_PLAYBACK)) ? 1 : 0;
885         }
886         mutex_unlock(&loopback->cable_lock);
887         ucontrol->value.integer.value[0] = val;
888         return 0;
889 }
890 
891 static int loopback_format_info(struct snd_kcontrol *kcontrol,   
892                                 struct snd_ctl_elem_info *uinfo) 
893 {
894         uinfo->type = SNDRV_CTL_ELEM_TYPE_INTEGER;
895         uinfo->count = 1;
896         uinfo->value.integer.min = 0;
897         uinfo->value.integer.max = SNDRV_PCM_FORMAT_LAST;
898         uinfo->value.integer.step = 1;
899         return 0;
900 }                                  
901 
902 static int loopback_format_get(struct snd_kcontrol *kcontrol,
903                                struct snd_ctl_elem_value *ucontrol)
904 {
905         struct loopback *loopback = snd_kcontrol_chip(kcontrol);
906         
907         ucontrol->value.integer.value[0] =
908                 loopback->setup[kcontrol->id.subdevice]
909                                [kcontrol->id.device].format;
910         return 0;
911 }
912 
913 static int loopback_rate_info(struct snd_kcontrol *kcontrol,   
914                               struct snd_ctl_elem_info *uinfo) 
915 {
916         uinfo->type = SNDRV_CTL_ELEM_TYPE_INTEGER;
917         uinfo->count = 1;
918         uinfo->value.integer.min = 0;
919         uinfo->value.integer.max = 192000;
920         uinfo->value.integer.step = 1;
921         return 0;
922 }                                  
923 
924 static int loopback_rate_get(struct snd_kcontrol *kcontrol,
925                              struct snd_ctl_elem_value *ucontrol)
926 {
927         struct loopback *loopback = snd_kcontrol_chip(kcontrol);
928         
929         mutex_lock(&loopback->cable_lock);
930         ucontrol->value.integer.value[0] =
931                 loopback->setup[kcontrol->id.subdevice]
932                                [kcontrol->id.device].rate;
933         mutex_unlock(&loopback->cable_lock);
934         return 0;
935 }
936 
937 static int loopback_channels_info(struct snd_kcontrol *kcontrol,   
938                                   struct snd_ctl_elem_info *uinfo) 
939 {
940         uinfo->type = SNDRV_CTL_ELEM_TYPE_INTEGER;
941         uinfo->count = 1;
942         uinfo->value.integer.min = 1;
943         uinfo->value.integer.max = 1024;
944         uinfo->value.integer.step = 1;
945         return 0;
946 }                                  
947 
948 static int loopback_channels_get(struct snd_kcontrol *kcontrol,
949                                  struct snd_ctl_elem_value *ucontrol)
950 {
951         struct loopback *loopback = snd_kcontrol_chip(kcontrol);
952         
953         mutex_lock(&loopback->cable_lock);
954         ucontrol->value.integer.value[0] =
955                 loopback->setup[kcontrol->id.subdevice]
956                                [kcontrol->id.device].channels;
957         mutex_unlock(&loopback->cable_lock);
958         return 0;
959 }
960 
961 static struct snd_kcontrol_new loopback_controls[]  = {
962 {
963         .iface =        SNDRV_CTL_ELEM_IFACE_PCM,
964         .name =         "PCM Rate Shift 100000",
965         .info =         loopback_rate_shift_info,
966         .get =          loopback_rate_shift_get,
967         .put =          loopback_rate_shift_put,
968 },
969 {
970         .iface =        SNDRV_CTL_ELEM_IFACE_PCM,
971         .name =         "PCM Notify",
972         .info =         snd_ctl_boolean_mono_info,
973         .get =          loopback_notify_get,
974         .put =          loopback_notify_put,
975 },
976 #define ACTIVE_IDX 2
977 {
978         .access =       SNDRV_CTL_ELEM_ACCESS_READ,
979         .iface =        SNDRV_CTL_ELEM_IFACE_PCM,
980         .name =         "PCM Slave Active",
981         .info =         snd_ctl_boolean_mono_info,
982         .get =          loopback_active_get,
983 },
984 #define FORMAT_IDX 3
985 {
986         .access =       SNDRV_CTL_ELEM_ACCESS_READ,
987         .iface =        SNDRV_CTL_ELEM_IFACE_PCM,
988         .name =         "PCM Slave Format",
989         .info =         loopback_format_info,
990         .get =          loopback_format_get
991 },
992 #define RATE_IDX 4
993 {
994         .access =       SNDRV_CTL_ELEM_ACCESS_READ,
995         .iface =        SNDRV_CTL_ELEM_IFACE_PCM,
996         .name =         "PCM Slave Rate",
997         .info =         loopback_rate_info,
998         .get =          loopback_rate_get
999 },
1000 #define CHANNELS_IDX 5
1001 {
1002         .access =       SNDRV_CTL_ELEM_ACCESS_READ,
1003         .iface =        SNDRV_CTL_ELEM_IFACE_PCM,
1004         .name =         "PCM Slave Channels",
1005         .info =         loopback_channels_info,
1006         .get =          loopback_channels_get
1007 }
1008 };
1009 
1010 static int loopback_mixer_new(struct loopback *loopback, int notify)
1011 {
1012         struct snd_card *card = loopback->card;
1013         struct snd_pcm *pcm;
1014         struct snd_kcontrol *kctl;
1015         struct loopback_setup *setup;
1016         int err, dev, substr, substr_count, idx;
1017 
1018         strcpy(card->mixername, "Loopback Mixer");
1019         for (dev = 0; dev < 2; dev++) {
1020                 pcm = loopback->pcm[dev];
1021                 substr_count =
1022                     pcm->streams[SNDRV_PCM_STREAM_CAPTURE].substream_count;
1023                 for (substr = 0; substr < substr_count; substr++) {
1024                         setup = &loopback->setup[substr][dev];
1025                         setup->notify = notify;
1026                         setup->rate_shift = NO_PITCH;
1027                         setup->format = SNDRV_PCM_FORMAT_S16_LE;
1028                         setup->rate = 48000;
1029                         setup->channels = 2;
1030                         for (idx = 0; idx < ARRAY_SIZE(loopback_controls);
1031                                                                         idx++) {
1032                                 kctl = snd_ctl_new1(&loopback_controls[idx],
1033                                                     loopback);
1034                                 if (!kctl)
1035                                         return -ENOMEM;
1036                                 kctl->id.device = dev;
1037                                 kctl->id.subdevice = substr;
1038                                 switch (idx) {
1039                                 case ACTIVE_IDX:
1040                                         setup->active_id = kctl->id;
1041                                         break;
1042                                 case FORMAT_IDX:
1043                                         setup->format_id = kctl->id;
1044                                         break;
1045                                 case RATE_IDX:
1046                                         setup->rate_id = kctl->id;
1047                                         break;
1048                                 case CHANNELS_IDX:
1049                                         setup->channels_id = kctl->id;
1050                                         break;
1051                                 default:
1052                                         break;
1053                                 }
1054                                 err = snd_ctl_add(card, kctl);
1055                                 if (err < 0)
1056                                         return err;
1057                         }
1058                 }
1059         }
1060         return 0;
1061 }
1062 
1063 static void print_dpcm_info(struct snd_info_buffer *buffer,
1064                             struct loopback_pcm *dpcm,
1065                             const char *id)
1066 {
1067         snd_iprintf(buffer, "  %s\n", id);
1068         if (dpcm == NULL) {
1069                 snd_iprintf(buffer, "    inactive\n");
1070                 return;
1071         }
1072         snd_iprintf(buffer, "    buffer_size:\t%u\n", dpcm->pcm_buffer_size);
1073         snd_iprintf(buffer, "    buffer_pos:\t\t%u\n", dpcm->buf_pos);
1074         snd_iprintf(buffer, "    silent_size:\t%u\n", dpcm->silent_size);
1075         snd_iprintf(buffer, "    period_size:\t%u\n", dpcm->pcm_period_size);
1076         snd_iprintf(buffer, "    bytes_per_sec:\t%u\n", dpcm->pcm_bps);
1077         snd_iprintf(buffer, "    sample_align:\t%u\n", dpcm->pcm_salign);
1078         snd_iprintf(buffer, "    rate_shift:\t\t%u\n", dpcm->pcm_rate_shift);
1079         snd_iprintf(buffer, "    update_pending:\t%u\n",
1080                                                 dpcm->period_update_pending);
1081         snd_iprintf(buffer, "    irq_pos:\t\t%u\n", dpcm->irq_pos);
1082         snd_iprintf(buffer, "    period_frac:\t%u\n", dpcm->period_size_frac);
1083         snd_iprintf(buffer, "    last_jiffies:\t%lu (%lu)\n",
1084                                         dpcm->last_jiffies, jiffies);
1085         snd_iprintf(buffer, "    timer_expires:\t%lu\n", dpcm->timer.expires);
1086 }
1087 
1088 static void print_substream_info(struct snd_info_buffer *buffer,
1089                                  struct loopback *loopback,
1090                                  int sub,
1091                                  int num)
1092 {
1093         struct loopback_cable *cable = loopback->cables[sub][num];
1094 
1095         snd_iprintf(buffer, "Cable %i substream %i:\n", num, sub);
1096         if (cable == NULL) {
1097                 snd_iprintf(buffer, "  inactive\n");
1098                 return;
1099         }
1100         snd_iprintf(buffer, "  valid: %u\n", cable->valid);
1101         snd_iprintf(buffer, "  running: %u\n", cable->running);
1102         snd_iprintf(buffer, "  pause: %u\n", cable->pause);
1103         print_dpcm_info(buffer, cable->streams[0], "Playback");
1104         print_dpcm_info(buffer, cable->streams[1], "Capture");
1105 }
1106 
1107 static void print_cable_info(struct snd_info_entry *entry,
1108                              struct snd_info_buffer *buffer)
1109 {
1110         struct loopback *loopback = entry->private_data;
1111         int sub, num;
1112 
1113         mutex_lock(&loopback->cable_lock);
1114         num = entry->name[strlen(entry->name)-1];
1115         num = num == '' ? 0 : 1;
1116         for (sub = 0; sub < MAX_PCM_SUBSTREAMS; sub++)
1117                 print_substream_info(buffer, loopback, sub, num);
1118         mutex_unlock(&loopback->cable_lock);
1119 }
1120 
1121 static int loopback_proc_new(struct loopback *loopback, int cidx)
1122 {
1123         char name[32];
1124 
1125         snprintf(name, sizeof(name), "cable#%d", cidx);
1126         return snd_card_ro_proc_new(loopback->card, name, loopback,
1127                                     print_cable_info);
1128 }
1129 
1130 static int loopback_probe(struct platform_device *devptr)
1131 {
1132         struct snd_card *card;
1133         struct loopback *loopback;
1134         int dev = devptr->id;
1135         int err;
1136 
1137         err = snd_card_new(&devptr->dev, index[dev], id[dev], THIS_MODULE,
1138                            sizeof(struct loopback), &card);
1139         if (err < 0)
1140                 return err;
1141         loopback = card->private_data;
1142 
1143         if (pcm_substreams[dev] < 1)
1144                 pcm_substreams[dev] = 1;
1145         if (pcm_substreams[dev] > MAX_PCM_SUBSTREAMS)
1146                 pcm_substreams[dev] = MAX_PCM_SUBSTREAMS;
1147         
1148         loopback->card = card;
1149         mutex_init(&loopback->cable_lock);
1150 
1151         err = loopback_pcm_new(loopback, 0, pcm_substreams[dev]);
1152         if (err < 0)
1153                 goto __nodev;
1154         err = loopback_pcm_new(loopback, 1, pcm_substreams[dev]);
1155         if (err < 0)
1156                 goto __nodev;
1157         err = loopback_mixer_new(loopback, pcm_notify[dev] ? 1 : 0);
1158         if (err < 0)
1159                 goto __nodev;
1160         loopback_proc_new(loopback, 0);
1161         loopback_proc_new(loopback, 1);
1162         strcpy(card->driver, "Loopback");
1163         strcpy(card->shortname, "Loopback");
1164         sprintf(card->longname, "Loopback %i", dev + 1);
1165         err = snd_card_register(card);
1166         if (!err) {
1167                 platform_set_drvdata(devptr, card);
1168                 return 0;
1169         }
1170       __nodev:
1171         snd_card_free(card);
1172         return err;
1173 }
1174 
1175 static int loopback_remove(struct platform_device *devptr)
1176 {
1177         snd_card_free(platform_get_drvdata(devptr));
1178         return 0;
1179 }
1180 
1181 #ifdef CONFIG_PM_SLEEP
1182 static int loopback_suspend(struct device *pdev)
1183 {
1184         struct snd_card *card = dev_get_drvdata(pdev);
1185 
1186         snd_power_change_state(card, SNDRV_CTL_POWER_D3hot);
1187         return 0;
1188 }
1189         
1190 static int loopback_resume(struct device *pdev)
1191 {
1192         struct snd_card *card = dev_get_drvdata(pdev);
1193 
1194         snd_power_change_state(card, SNDRV_CTL_POWER_D0);
1195         return 0;
1196 }
1197 
1198 static SIMPLE_DEV_PM_OPS(loopback_pm, loopback_suspend, loopback_resume);
1199 #define LOOPBACK_PM_OPS &loopback_pm
1200 #else
1201 #define LOOPBACK_PM_OPS NULL
1202 #endif
1203 
1204 #define SND_LOOPBACK_DRIVER     "snd_aloop"
1205 
1206 static struct platform_driver loopback_driver = {
1207         .probe          = loopback_probe,
1208         .remove         = loopback_remove,
1209         .driver         = {
1210                 .name   = SND_LOOPBACK_DRIVER,
1211                 .pm     = LOOPBACK_PM_OPS,
1212         },
1213 };
1214 
1215 static void loopback_unregister_all(void)
1216 {
1217         int i;
1218 
1219         for (i = 0; i < ARRAY_SIZE(devices); ++i)
1220                 platform_device_unregister(devices[i]);
1221         platform_driver_unregister(&loopback_driver);
1222 }
1223 
1224 static int __init alsa_card_loopback_init(void)
1225 {
1226         int i, err, cards;
1227 
1228         err = platform_driver_register(&loopback_driver);
1229         if (err < 0)
1230                 return err;
1231 
1232 
1233         cards = 0;
1234         for (i = 0; i < SNDRV_CARDS; i++) {
1235                 struct platform_device *device;
1236                 if (!enable[i])
1237                         continue;
1238                 device = platform_device_register_simple(SND_LOOPBACK_DRIVER,
1239                                                          i, NULL, 0);
1240                 if (IS_ERR(device))
1241                         continue;
1242                 if (!platform_get_drvdata(device)) {
1243                         platform_device_unregister(device);
1244                         continue;
1245                 }
1246                 devices[i] = device;
1247                 cards++;
1248         }
1249         if (!cards) {
1250 #ifdef MODULE
1251                 printk(KERN_ERR "aloop: No loopback enabled\n");
1252 #endif
1253                 loopback_unregister_all();
1254                 return -ENODEV;
1255         }
1256         return 0;
1257 }
1258 
1259 static void __exit alsa_card_loopback_exit(void)
1260 {
1261         loopback_unregister_all();
1262 }
1263 
1264 module_init(alsa_card_loopback_init)
1265 module_exit(alsa_card_loopback_exit)
1266 

~ [ source navigation ] ~ [ diff markup ] ~ [ identifier search ] ~

kernel.org | git.kernel.org | LWN.net | Project Home | Wiki (Japanese) | Wiki (English) | SVN repository | Mail admin

Linux® is a registered trademark of Linus Torvalds in the United States and other countries.
TOMOYO® is a registered trademark of NTT DATA CORPORATION.

osdn.jp