ALSA: aloop - Fix possible IRQ lock inversion
[linux-3.10.git] / sound / drivers / aloop.c
1 /*
2  *  Loopback soundcard
3  *
4  *  Original code:
5  *  Copyright (c) by Jaroslav Kysela <perex@perex.cz>
6  *
7  *  More accurate positioning and full-duplex support:
8  *  Copyright (c) Ahmet ─░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/moduleparam.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 int 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 long last_jiffies;
121         struct timer_list timer;
122 };
123
124 static struct platform_device *devices[SNDRV_CARDS];
125
126 static inline unsigned int byte_pos(struct loopback_pcm *dpcm, unsigned int x)
127 {
128         if (dpcm->pcm_rate_shift == NO_PITCH) {
129                 x /= HZ;
130         } else {
131                 x = div_u64(NO_PITCH * (unsigned long long)x,
132                             HZ * (unsigned long long)dpcm->pcm_rate_shift);
133         }
134         return x - (x % dpcm->pcm_salign);
135 }
136
137 static inline unsigned int frac_pos(struct loopback_pcm *dpcm, unsigned int x)
138 {
139         if (dpcm->pcm_rate_shift == NO_PITCH) { /* no pitch */
140                 return x * HZ;
141         } else {
142                 x = div_u64(dpcm->pcm_rate_shift * (unsigned long long)x * HZ,
143                             NO_PITCH);
144         }
145         return x;
146 }
147
148 static inline struct loopback_setup *get_setup(struct loopback_pcm *dpcm)
149 {
150         int device = dpcm->substream->pstr->pcm->device;
151         
152         if (dpcm->substream->stream == SNDRV_PCM_STREAM_PLAYBACK)
153                 device ^= 1;
154         return &dpcm->loopback->setup[dpcm->substream->number][device];
155 }
156
157 static inline unsigned int get_notify(struct loopback_pcm *dpcm)
158 {
159         return get_setup(dpcm)->notify;
160 }
161
162 static inline unsigned int get_rate_shift(struct loopback_pcm *dpcm)
163 {
164         return get_setup(dpcm)->rate_shift;
165 }
166
167 static void loopback_timer_start(struct loopback_pcm *dpcm)
168 {
169         unsigned long tick;
170         unsigned int rate_shift = get_rate_shift(dpcm);
171
172         if (rate_shift != dpcm->pcm_rate_shift) {
173                 dpcm->pcm_rate_shift = rate_shift;
174                 dpcm->period_size_frac = frac_pos(dpcm, dpcm->pcm_period_size);
175         }
176         if (dpcm->period_size_frac <= dpcm->irq_pos) {
177                 dpcm->irq_pos %= dpcm->period_size_frac;
178                 dpcm->period_update_pending = 1;
179         }
180         tick = dpcm->period_size_frac - dpcm->irq_pos;
181         tick = (tick + dpcm->pcm_bps - 1) / dpcm->pcm_bps;
182         dpcm->timer.expires = jiffies + tick;
183         add_timer(&dpcm->timer);
184 }
185
186 static inline void loopback_timer_stop(struct loopback_pcm *dpcm)
187 {
188         del_timer(&dpcm->timer);
189         dpcm->timer.expires = 0;
190 }
191
192 #define CABLE_VALID_PLAYBACK    (1 << SNDRV_PCM_STREAM_PLAYBACK)
193 #define CABLE_VALID_CAPTURE     (1 << SNDRV_PCM_STREAM_CAPTURE)
194 #define CABLE_VALID_BOTH        (CABLE_VALID_PLAYBACK|CABLE_VALID_CAPTURE)
195
196 static int loopback_check_format(struct loopback_cable *cable, int stream)
197 {
198         struct snd_pcm_runtime *runtime, *cruntime;
199         struct loopback_setup *setup;
200         struct snd_card *card;
201         int check;
202
203         if (cable->valid != CABLE_VALID_BOTH) {
204                 if (stream == SNDRV_PCM_STREAM_PLAYBACK)
205                         goto __notify;
206                 return 0;
207         }
208         runtime = cable->streams[SNDRV_PCM_STREAM_PLAYBACK]->
209                                                         substream->runtime;
210         cruntime = cable->streams[SNDRV_PCM_STREAM_CAPTURE]->
211                                                         substream->runtime;
212         check = runtime->format != cruntime->format ||
213                 runtime->rate != cruntime->rate ||
214                 runtime->channels != cruntime->channels;
215         if (!check)
216                 return 0;
217         if (stream == SNDRV_PCM_STREAM_CAPTURE) {
218                 return -EIO;
219         } else {
220                 snd_pcm_stop(cable->streams[SNDRV_PCM_STREAM_CAPTURE]->
221                                         substream, SNDRV_PCM_STATE_DRAINING);
222               __notify:
223                 runtime = cable->streams[SNDRV_PCM_STREAM_PLAYBACK]->
224                                                         substream->runtime;
225                 setup = get_setup(cable->streams[SNDRV_PCM_STREAM_PLAYBACK]);
226                 card = cable->streams[SNDRV_PCM_STREAM_PLAYBACK]->loopback->card;
227                 if (setup->format != runtime->format) {
228                         snd_ctl_notify(card, SNDRV_CTL_EVENT_MASK_VALUE,
229                                                         &setup->format_id);
230                         setup->format = runtime->format;
231                 }
232                 if (setup->rate != runtime->rate) {
233                         snd_ctl_notify(card, SNDRV_CTL_EVENT_MASK_VALUE,
234                                                         &setup->rate_id);
235                         setup->rate = runtime->rate;
236                 }
237                 if (setup->channels != runtime->channels) {
238                         snd_ctl_notify(card, SNDRV_CTL_EVENT_MASK_VALUE,
239                                                         &setup->channels_id);
240                         setup->channels = runtime->channels;
241                 }
242         }
243         return 0;
244 }
245
246 static void loopback_active_notify(struct loopback_pcm *dpcm)
247 {
248         snd_ctl_notify(dpcm->loopback->card,
249                        SNDRV_CTL_EVENT_MASK_VALUE,
250                        &get_setup(dpcm)->active_id);
251 }
252
253 static int loopback_trigger(struct snd_pcm_substream *substream, int cmd)
254 {
255         struct snd_pcm_runtime *runtime = substream->runtime;
256         struct loopback_pcm *dpcm = runtime->private_data;
257         struct loopback_cable *cable = dpcm->cable;
258         int err, stream = 1 << substream->stream;
259
260         switch (cmd) {
261         case SNDRV_PCM_TRIGGER_START:
262                 err = loopback_check_format(cable, substream->stream);
263                 if (err < 0)
264                         return err;
265                 dpcm->last_jiffies = jiffies;
266                 dpcm->pcm_rate_shift = 0;
267                 spin_lock(&cable->lock);        
268                 cable->running |= stream;
269                 cable->pause &= ~stream;
270                 spin_unlock(&cable->lock);
271                 loopback_timer_start(dpcm);
272                 if (substream->stream == SNDRV_PCM_STREAM_PLAYBACK)
273                         loopback_active_notify(dpcm);
274                 break;
275         case SNDRV_PCM_TRIGGER_STOP:
276                 spin_lock(&cable->lock);        
277                 cable->running &= ~stream;
278                 cable->pause &= ~stream;
279                 spin_unlock(&cable->lock);
280                 loopback_timer_stop(dpcm);
281                 if (substream->stream == SNDRV_PCM_STREAM_PLAYBACK)
282                         loopback_active_notify(dpcm);
283                 break;
284         case SNDRV_PCM_TRIGGER_PAUSE_PUSH:
285                 spin_lock(&cable->lock);        
286                 cable->pause |= stream;
287                 spin_unlock(&cable->lock);
288                 loopback_timer_stop(dpcm);
289                 break;
290         case SNDRV_PCM_TRIGGER_PAUSE_RELEASE:
291                 spin_lock(&cable->lock);
292                 dpcm->last_jiffies = jiffies;
293                 cable->pause &= ~stream;
294                 spin_unlock(&cable->lock);
295                 loopback_timer_start(dpcm);
296                 break;
297         default:
298                 return -EINVAL;
299         }
300         return 0;
301 }
302
303 static void params_change_substream(struct loopback_pcm *dpcm,
304                                     struct snd_pcm_runtime *runtime)
305 {
306         struct snd_pcm_runtime *dst_runtime;
307
308         if (dpcm == NULL || dpcm->substream == NULL)
309                 return;
310         dst_runtime = dpcm->substream->runtime;
311         if (dst_runtime == NULL)
312                 return;
313         dst_runtime->hw = dpcm->cable->hw;
314 }
315
316 static void params_change(struct snd_pcm_substream *substream)
317 {
318         struct snd_pcm_runtime *runtime = substream->runtime;
319         struct loopback_pcm *dpcm = runtime->private_data;
320         struct loopback_cable *cable = dpcm->cable;
321
322         cable->hw.formats = (1ULL << runtime->format);
323         cable->hw.rate_min = runtime->rate;
324         cable->hw.rate_max = runtime->rate;
325         cable->hw.channels_min = runtime->channels;
326         cable->hw.channels_max = runtime->channels;
327         params_change_substream(cable->streams[SNDRV_PCM_STREAM_PLAYBACK],
328                                 runtime);
329         params_change_substream(cable->streams[SNDRV_PCM_STREAM_CAPTURE],
330                                 runtime);
331 }
332
333 static int loopback_prepare(struct snd_pcm_substream *substream)
334 {
335         struct snd_pcm_runtime *runtime = substream->runtime;
336         struct loopback_pcm *dpcm = runtime->private_data;
337         struct loopback_cable *cable = dpcm->cable;
338         int bps, salign;
339
340         salign = (snd_pcm_format_width(runtime->format) *
341                                                 runtime->channels) / 8;
342         bps = salign * runtime->rate;
343         if (bps <= 0 || salign <= 0)
344                 return -EINVAL;
345
346         dpcm->buf_pos = 0;
347         dpcm->pcm_buffer_size = frames_to_bytes(runtime, runtime->buffer_size);
348         if (substream->stream == SNDRV_PCM_STREAM_CAPTURE) {
349                 /* clear capture buffer */
350                 dpcm->silent_size = dpcm->pcm_buffer_size;
351                 snd_pcm_format_set_silence(runtime->format, runtime->dma_area,
352                                            runtime->buffer_size * runtime->channels);
353         }
354
355         dpcm->irq_pos = 0;
356         dpcm->period_update_pending = 0;
357         dpcm->pcm_bps = bps;
358         dpcm->pcm_salign = salign;
359         dpcm->pcm_period_size = frames_to_bytes(runtime, runtime->period_size);
360
361         mutex_lock(&dpcm->loopback->cable_lock);
362         if (!(cable->valid & ~(1 << substream->stream)) ||
363             (get_setup(dpcm)->notify &&
364              substream->stream == SNDRV_PCM_STREAM_PLAYBACK))
365                 params_change(substream);
366         cable->valid |= 1 << substream->stream;
367         mutex_unlock(&dpcm->loopback->cable_lock);
368
369         return 0;
370 }
371
372 static void clear_capture_buf(struct loopback_pcm *dpcm, unsigned int bytes)
373 {
374         struct snd_pcm_runtime *runtime = dpcm->substream->runtime;
375         char *dst = runtime->dma_area;
376         unsigned int dst_off = dpcm->buf_pos;
377
378         if (dpcm->silent_size >= dpcm->pcm_buffer_size)
379                 return;
380         if (dpcm->silent_size + bytes > dpcm->pcm_buffer_size)
381                 bytes = dpcm->pcm_buffer_size - dpcm->silent_size;
382
383         for (;;) {
384                 unsigned int size = bytes;
385                 if (dst_off + size > dpcm->pcm_buffer_size)
386                         size = dpcm->pcm_buffer_size - dst_off;
387                 snd_pcm_format_set_silence(runtime->format, dst + dst_off,
388                                            bytes_to_frames(runtime, size) *
389                                                 runtime->channels);
390                 dpcm->silent_size += size;
391                 bytes -= size;
392                 if (!bytes)
393                         break;
394                 dst_off = 0;
395         }
396 }
397
398 static void copy_play_buf(struct loopback_pcm *play,
399                           struct loopback_pcm *capt,
400                           unsigned int bytes)
401 {
402         struct snd_pcm_runtime *runtime = play->substream->runtime;
403         char *src = runtime->dma_area;
404         char *dst = capt->substream->runtime->dma_area;
405         unsigned int src_off = play->buf_pos;
406         unsigned int dst_off = capt->buf_pos;
407         unsigned int clear_bytes = 0;
408
409         /* check if playback is draining, trim the capture copy size
410          * when our pointer is at the end of playback ring buffer */
411         if (runtime->status->state == SNDRV_PCM_STATE_DRAINING &&
412             snd_pcm_playback_hw_avail(runtime) < runtime->buffer_size) { 
413                 snd_pcm_uframes_t appl_ptr, appl_ptr1, diff;
414                 appl_ptr = appl_ptr1 = runtime->control->appl_ptr;
415                 appl_ptr1 -= appl_ptr1 % runtime->buffer_size;
416                 appl_ptr1 += play->buf_pos / play->pcm_salign;
417                 if (appl_ptr < appl_ptr1)
418                         appl_ptr1 -= runtime->buffer_size;
419                 diff = (appl_ptr - appl_ptr1) * play->pcm_salign;
420                 if (diff < bytes) {
421                         clear_bytes = bytes - diff;
422                         bytes = diff;
423                 }
424         }
425
426         for (;;) {
427                 unsigned int size = bytes;
428                 if (src_off + size > play->pcm_buffer_size)
429                         size = play->pcm_buffer_size - src_off;
430                 if (dst_off + size > capt->pcm_buffer_size)
431                         size = capt->pcm_buffer_size - dst_off;
432                 memcpy(dst + dst_off, src + src_off, size);
433                 capt->silent_size = 0;
434                 bytes -= size;
435                 if (!bytes)
436                         break;
437                 src_off = (src_off + size) % play->pcm_buffer_size;
438                 dst_off = (dst_off + size) % capt->pcm_buffer_size;
439         }
440
441         if (clear_bytes > 0) {
442                 clear_capture_buf(capt, clear_bytes);
443                 capt->silent_size = 0;
444         }
445 }
446
447 #define BYTEPOS_UPDATE_POSONLY  0
448 #define BYTEPOS_UPDATE_CLEAR    1
449 #define BYTEPOS_UPDATE_COPY     2
450
451 static void loopback_bytepos_update(struct loopback_pcm *dpcm,
452                                     unsigned int delta,
453                                     unsigned int cmd)
454 {
455         unsigned int count;
456         unsigned long last_pos;
457
458         last_pos = byte_pos(dpcm, dpcm->irq_pos);
459         dpcm->irq_pos += delta * dpcm->pcm_bps;
460         count = byte_pos(dpcm, dpcm->irq_pos) - last_pos;
461         if (!count)
462                 return;
463         if (cmd == BYTEPOS_UPDATE_CLEAR)
464                 clear_capture_buf(dpcm, count);
465         else if (cmd == BYTEPOS_UPDATE_COPY)
466                 copy_play_buf(dpcm->cable->streams[SNDRV_PCM_STREAM_PLAYBACK],
467                               dpcm->cable->streams[SNDRV_PCM_STREAM_CAPTURE],
468                               count);
469         dpcm->buf_pos += count;
470         dpcm->buf_pos %= dpcm->pcm_buffer_size;
471         if (dpcm->irq_pos >= dpcm->period_size_frac) {
472                 dpcm->irq_pos %= dpcm->period_size_frac;
473                 dpcm->period_update_pending = 1;
474         }
475 }
476
477 static unsigned int loopback_pos_update(struct loopback_cable *cable)
478 {
479         struct loopback_pcm *dpcm_play =
480                         cable->streams[SNDRV_PCM_STREAM_PLAYBACK];
481         struct loopback_pcm *dpcm_capt =
482                         cable->streams[SNDRV_PCM_STREAM_CAPTURE];
483         unsigned long delta_play = 0, delta_capt = 0;
484         unsigned int running;
485         unsigned long flags;
486
487         spin_lock_irqsave(&cable->lock, flags);
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                 loopback_bytepos_update(dpcm_play, delta_play - delta_capt,
504                                         BYTEPOS_UPDATE_POSONLY);
505                 delta_play = delta_capt;
506         } else if (delta_play < delta_capt) {
507                 loopback_bytepos_update(dpcm_capt, delta_capt - delta_play,
508                                         BYTEPOS_UPDATE_CLEAR);
509                 delta_capt = delta_play;
510         }
511
512         if (delta_play == 0 && delta_capt == 0)
513                 goto unlock;
514
515         /* note delta_capt == delta_play at this moment */
516         loopback_bytepos_update(dpcm_capt, delta_capt, BYTEPOS_UPDATE_COPY);
517         loopback_bytepos_update(dpcm_play, delta_play, BYTEPOS_UPDATE_POSONLY);
518  unlock:
519         spin_unlock_irqrestore(&cable->lock, flags);
520         return running;
521 }
522
523 static void loopback_timer_function(unsigned long data)
524 {
525         struct loopback_pcm *dpcm = (struct loopback_pcm *)data;
526         unsigned int running;
527
528         running = loopback_pos_update(dpcm->cable);
529         if (running & (1 << dpcm->substream->stream)) {
530                 loopback_timer_start(dpcm);
531                 if (dpcm->period_update_pending) {
532                         dpcm->period_update_pending = 0;
533                         snd_pcm_period_elapsed(dpcm->substream);
534                 }
535         }
536 }
537
538 static snd_pcm_uframes_t loopback_pointer(struct snd_pcm_substream *substream)
539 {
540         struct snd_pcm_runtime *runtime = substream->runtime;
541         struct loopback_pcm *dpcm = runtime->private_data;
542
543         loopback_pos_update(dpcm->cable);
544         return bytes_to_frames(runtime, dpcm->buf_pos);
545 }
546
547 static struct snd_pcm_hardware loopback_pcm_hardware =
548 {
549         .info =         (SNDRV_PCM_INFO_INTERLEAVED | SNDRV_PCM_INFO_MMAP |
550                          SNDRV_PCM_INFO_MMAP_VALID | SNDRV_PCM_INFO_PAUSE),
551         .formats =      (SNDRV_PCM_FMTBIT_S16_LE | SNDRV_PCM_FMTBIT_S16_BE |
552                          SNDRV_PCM_FMTBIT_S32_LE | SNDRV_PCM_FMTBIT_S32_BE |
553                          SNDRV_PCM_FMTBIT_FLOAT_LE | SNDRV_PCM_FMTBIT_FLOAT_BE),
554         .rates =        SNDRV_PCM_RATE_CONTINUOUS | SNDRV_PCM_RATE_8000_192000,
555         .rate_min =             8000,
556         .rate_max =             192000,
557         .channels_min =         1,
558         .channels_max =         32,
559         .buffer_bytes_max =     2 * 1024 * 1024,
560         .period_bytes_min =     64,
561         /* note check overflow in frac_pos() using pcm_rate_shift before
562            changing period_bytes_max value */
563         .period_bytes_max =     1024 * 1024,
564         .periods_min =          1,
565         .periods_max =          1024,
566         .fifo_size =            0,
567 };
568
569 static void loopback_runtime_free(struct snd_pcm_runtime *runtime)
570 {
571         struct loopback_pcm *dpcm = runtime->private_data;
572         kfree(dpcm);
573 }
574
575 static int loopback_hw_params(struct snd_pcm_substream *substream,
576                               struct snd_pcm_hw_params *params)
577 {
578         return snd_pcm_lib_malloc_pages(substream, params_buffer_bytes(params));
579 }
580
581 static int loopback_hw_free(struct snd_pcm_substream *substream)
582 {
583         struct snd_pcm_runtime *runtime = substream->runtime;
584         struct loopback_pcm *dpcm = runtime->private_data;
585         struct loopback_cable *cable = dpcm->cable;
586
587         mutex_lock(&dpcm->loopback->cable_lock);
588         cable->valid &= ~(1 << substream->stream);
589         mutex_unlock(&dpcm->loopback->cable_lock);
590         return snd_pcm_lib_free_pages(substream);
591 }
592
593 static unsigned int get_cable_index(struct snd_pcm_substream *substream)
594 {
595         if (!substream->pcm->device)
596                 return substream->stream;
597         else
598                 return !substream->stream;
599 }
600
601 static int rule_format(struct snd_pcm_hw_params *params,
602                        struct snd_pcm_hw_rule *rule)
603 {
604
605         struct snd_pcm_hardware *hw = rule->private;
606         struct snd_mask *maskp = hw_param_mask(params, rule->var);
607
608         maskp->bits[0] &= (u_int32_t)hw->formats;
609         maskp->bits[1] &= (u_int32_t)(hw->formats >> 32);
610         memset(maskp->bits + 2, 0, (SNDRV_MASK_MAX-64) / 8); /* clear rest */
611         if (! maskp->bits[0] && ! maskp->bits[1])
612                 return -EINVAL;
613         return 0;
614 }
615
616 static int rule_rate(struct snd_pcm_hw_params *params,
617                      struct snd_pcm_hw_rule *rule)
618 {
619         struct snd_pcm_hardware *hw = rule->private;
620         struct snd_interval t;
621
622         t.min = hw->rate_min;
623         t.max = hw->rate_max;
624         t.openmin = t.openmax = 0;
625         t.integer = 0;
626         return snd_interval_refine(hw_param_interval(params, rule->var), &t);
627 }
628
629 static int rule_channels(struct snd_pcm_hw_params *params,
630                          struct snd_pcm_hw_rule *rule)
631 {
632         struct snd_pcm_hardware *hw = rule->private;
633         struct snd_interval t;
634
635         t.min = hw->channels_min;
636         t.max = hw->channels_max;
637         t.openmin = t.openmax = 0;
638         t.integer = 0;
639         return snd_interval_refine(hw_param_interval(params, rule->var), &t);
640 }
641
642 static int loopback_open(struct snd_pcm_substream *substream)
643 {
644         struct snd_pcm_runtime *runtime = substream->runtime;
645         struct loopback *loopback = substream->private_data;
646         struct loopback_pcm *dpcm;
647         struct loopback_cable *cable;
648         int err = 0;
649         int dev = get_cable_index(substream);
650
651         mutex_lock(&loopback->cable_lock);
652         dpcm = kzalloc(sizeof(*dpcm), GFP_KERNEL);
653         if (!dpcm) {
654                 err = -ENOMEM;
655                 goto unlock;
656         }
657         dpcm->loopback = loopback;
658         dpcm->substream = substream;
659         setup_timer(&dpcm->timer, loopback_timer_function,
660                     (unsigned long)dpcm);
661
662         cable = loopback->cables[substream->number][dev];
663         if (!cable) {
664                 cable = kzalloc(sizeof(*cable), GFP_KERNEL);
665                 if (!cable) {
666                         kfree(dpcm);
667                         err = -ENOMEM;
668                         goto unlock;
669                 }
670                 spin_lock_init(&cable->lock);
671                 cable->hw = loopback_pcm_hardware;
672                 loopback->cables[substream->number][dev] = cable;
673         }
674         dpcm->cable = cable;
675         cable->streams[substream->stream] = dpcm;
676
677         snd_pcm_hw_constraint_integer(runtime, SNDRV_PCM_HW_PARAM_PERIODS);
678
679         /* use dynamic rules based on actual runtime->hw values */
680         /* note that the default rules created in the PCM midlevel code */
681         /* are cached -> they do not reflect the actual state */
682         err = snd_pcm_hw_rule_add(runtime, 0,
683                                   SNDRV_PCM_HW_PARAM_FORMAT,
684                                   rule_format, &runtime->hw,
685                                   SNDRV_PCM_HW_PARAM_FORMAT, -1);
686         if (err < 0)
687                 goto unlock;
688         err = snd_pcm_hw_rule_add(runtime, 0,
689                                   SNDRV_PCM_HW_PARAM_RATE,
690                                   rule_rate, &runtime->hw,
691                                   SNDRV_PCM_HW_PARAM_RATE, -1);
692         if (err < 0)
693                 goto unlock;
694         err = snd_pcm_hw_rule_add(runtime, 0,
695                                   SNDRV_PCM_HW_PARAM_CHANNELS,
696                                   rule_channels, &runtime->hw,
697                                   SNDRV_PCM_HW_PARAM_CHANNELS, -1);
698         if (err < 0)
699                 goto unlock;
700
701         runtime->private_data = dpcm;
702         runtime->private_free = loopback_runtime_free;
703         if (get_notify(dpcm))
704                 runtime->hw = loopback_pcm_hardware;
705         else
706                 runtime->hw = cable->hw;
707  unlock:
708         mutex_unlock(&loopback->cable_lock);
709         return err;
710 }
711
712 static int loopback_close(struct snd_pcm_substream *substream)
713 {
714         struct loopback *loopback = substream->private_data;
715         struct loopback_pcm *dpcm = substream->runtime->private_data;
716         struct loopback_cable *cable;
717         int dev = get_cable_index(substream);
718
719         loopback_timer_stop(dpcm);
720         mutex_lock(&loopback->cable_lock);
721         cable = loopback->cables[substream->number][dev];
722         if (cable->streams[!substream->stream]) {
723                 /* other stream is still alive */
724                 cable->streams[substream->stream] = NULL;
725         } else {
726                 /* free the cable */
727                 loopback->cables[substream->number][dev] = NULL;
728                 kfree(cable);
729         }
730         mutex_unlock(&loopback->cable_lock);
731         return 0;
732 }
733
734 static struct snd_pcm_ops loopback_playback_ops = {
735         .open =         loopback_open,
736         .close =        loopback_close,
737         .ioctl =        snd_pcm_lib_ioctl,
738         .hw_params =    loopback_hw_params,
739         .hw_free =      loopback_hw_free,
740         .prepare =      loopback_prepare,
741         .trigger =      loopback_trigger,
742         .pointer =      loopback_pointer,
743 };
744
745 static struct snd_pcm_ops loopback_capture_ops = {
746         .open =         loopback_open,
747         .close =        loopback_close,
748         .ioctl =        snd_pcm_lib_ioctl,
749         .hw_params =    loopback_hw_params,
750         .hw_free =      loopback_hw_free,
751         .prepare =      loopback_prepare,
752         .trigger =      loopback_trigger,
753         .pointer =      loopback_pointer,
754 };
755
756 static int __devinit loopback_pcm_new(struct loopback *loopback,
757                                       int device, int substreams)
758 {
759         struct snd_pcm *pcm;
760         int err;
761
762         err = snd_pcm_new(loopback->card, "Loopback PCM", device,
763                           substreams, substreams, &pcm);
764         if (err < 0)
765                 return err;
766         snd_pcm_set_ops(pcm, SNDRV_PCM_STREAM_PLAYBACK, &loopback_playback_ops);
767         snd_pcm_set_ops(pcm, SNDRV_PCM_STREAM_CAPTURE, &loopback_capture_ops);
768
769         pcm->private_data = loopback;
770         pcm->info_flags = 0;
771         strcpy(pcm->name, "Loopback PCM");
772
773         loopback->pcm[device] = pcm;
774
775         snd_pcm_lib_preallocate_pages_for_all(pcm, SNDRV_DMA_TYPE_CONTINUOUS,
776                         snd_dma_continuous_data(GFP_KERNEL),
777                         0, 2 * 1024 * 1024);
778         return 0;
779 }
780
781 static int loopback_rate_shift_info(struct snd_kcontrol *kcontrol,   
782                                     struct snd_ctl_elem_info *uinfo) 
783 {
784         uinfo->type = SNDRV_CTL_ELEM_TYPE_INTEGER;
785         uinfo->count = 1;
786         uinfo->value.integer.min = 80000;
787         uinfo->value.integer.max = 120000;
788         uinfo->value.integer.step = 1;
789         return 0;
790 }                                  
791
792 static int loopback_rate_shift_get(struct snd_kcontrol *kcontrol,
793                                    struct snd_ctl_elem_value *ucontrol)
794 {
795         struct loopback *loopback = snd_kcontrol_chip(kcontrol);
796         
797         ucontrol->value.integer.value[0] =
798                 loopback->setup[kcontrol->id.subdevice]
799                                [kcontrol->id.device].rate_shift;
800         return 0;
801 }
802
803 static int loopback_rate_shift_put(struct snd_kcontrol *kcontrol,
804                                    struct snd_ctl_elem_value *ucontrol)
805 {
806         struct loopback *loopback = snd_kcontrol_chip(kcontrol);
807         unsigned int val;
808         int change = 0;
809
810         val = ucontrol->value.integer.value[0];
811         if (val < 80000)
812                 val = 80000;
813         if (val > 120000)
814                 val = 120000;   
815         mutex_lock(&loopback->cable_lock);
816         if (val != loopback->setup[kcontrol->id.subdevice]
817                                   [kcontrol->id.device].rate_shift) {
818                 loopback->setup[kcontrol->id.subdevice]
819                                [kcontrol->id.device].rate_shift = val;
820                 change = 1;
821         }
822         mutex_unlock(&loopback->cable_lock);
823         return change;
824 }
825
826 static int loopback_notify_get(struct snd_kcontrol *kcontrol,
827                                struct snd_ctl_elem_value *ucontrol)
828 {
829         struct loopback *loopback = snd_kcontrol_chip(kcontrol);
830         
831         ucontrol->value.integer.value[0] =
832                 loopback->setup[kcontrol->id.subdevice]
833                                [kcontrol->id.device].notify;
834         return 0;
835 }
836
837 static int loopback_notify_put(struct snd_kcontrol *kcontrol,
838                                struct snd_ctl_elem_value *ucontrol)
839 {
840         struct loopback *loopback = snd_kcontrol_chip(kcontrol);
841         unsigned int val;
842         int change = 0;
843
844         val = ucontrol->value.integer.value[0] ? 1 : 0;
845         if (val != loopback->setup[kcontrol->id.subdevice]
846                                 [kcontrol->id.device].notify) {
847                 loopback->setup[kcontrol->id.subdevice]
848                         [kcontrol->id.device].notify = val;
849                 change = 1;
850         }
851         return change;
852 }
853
854 static int loopback_active_get(struct snd_kcontrol *kcontrol,
855                                struct snd_ctl_elem_value *ucontrol)
856 {
857         struct loopback *loopback = snd_kcontrol_chip(kcontrol);
858         struct loopback_cable *cable = loopback->cables
859                         [kcontrol->id.subdevice][kcontrol->id.device ^ 1];
860         unsigned int val = 0;
861
862         if (cable != NULL)
863                 val = (cable->running & (1 << SNDRV_PCM_STREAM_PLAYBACK)) ?
864                                                                         1 : 0;
865         ucontrol->value.integer.value[0] = val;
866         return 0;
867 }
868
869 static int loopback_format_info(struct snd_kcontrol *kcontrol,   
870                                 struct snd_ctl_elem_info *uinfo) 
871 {
872         uinfo->type = SNDRV_CTL_ELEM_TYPE_INTEGER;
873         uinfo->count = 1;
874         uinfo->value.integer.min = 0;
875         uinfo->value.integer.max = SNDRV_PCM_FORMAT_LAST;
876         uinfo->value.integer.step = 1;
877         return 0;
878 }                                  
879
880 static int loopback_format_get(struct snd_kcontrol *kcontrol,
881                                struct snd_ctl_elem_value *ucontrol)
882 {
883         struct loopback *loopback = snd_kcontrol_chip(kcontrol);
884         
885         ucontrol->value.integer.value[0] =
886                 loopback->setup[kcontrol->id.subdevice]
887                                [kcontrol->id.device].format;
888         return 0;
889 }
890
891 static int loopback_rate_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 = 192000;
898         uinfo->value.integer.step = 1;
899         return 0;
900 }                                  
901
902 static int loopback_rate_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].rate;
910         return 0;
911 }
912
913 static int loopback_channels_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 = 1;
919         uinfo->value.integer.max = 1024;
920         uinfo->value.integer.step = 1;
921         return 0;
922 }                                  
923
924 static int loopback_channels_get(struct snd_kcontrol *kcontrol,
925                                  struct snd_ctl_elem_value *ucontrol)
926 {
927         struct loopback *loopback = snd_kcontrol_chip(kcontrol);
928         
929         ucontrol->value.integer.value[0] =
930                 loopback->setup[kcontrol->id.subdevice]
931                                [kcontrol->id.device].channels;
932         return 0;
933 }
934
935 static struct snd_kcontrol_new loopback_controls[]  __devinitdata = {
936 {
937         .iface =        SNDRV_CTL_ELEM_IFACE_PCM,
938         .name =         "PCM Rate Shift 100000",
939         .info =         loopback_rate_shift_info,
940         .get =          loopback_rate_shift_get,
941         .put =          loopback_rate_shift_put,
942 },
943 {
944         .iface =        SNDRV_CTL_ELEM_IFACE_PCM,
945         .name =         "PCM Notify",
946         .info =         snd_ctl_boolean_mono_info,
947         .get =          loopback_notify_get,
948         .put =          loopback_notify_put,
949 },
950 #define ACTIVE_IDX 2
951 {
952         .access =       SNDRV_CTL_ELEM_ACCESS_READ,
953         .iface =        SNDRV_CTL_ELEM_IFACE_PCM,
954         .name =         "PCM Slave Active",
955         .info =         snd_ctl_boolean_mono_info,
956         .get =          loopback_active_get,
957 },
958 #define FORMAT_IDX 3
959 {
960         .access =       SNDRV_CTL_ELEM_ACCESS_READ,
961         .iface =        SNDRV_CTL_ELEM_IFACE_PCM,
962         .name =         "PCM Slave Format",
963         .info =         loopback_format_info,
964         .get =          loopback_format_get
965 },
966 #define RATE_IDX 4
967 {
968         .access =       SNDRV_CTL_ELEM_ACCESS_READ,
969         .iface =        SNDRV_CTL_ELEM_IFACE_PCM,
970         .name =         "PCM Slave Rate",
971         .info =         loopback_rate_info,
972         .get =          loopback_rate_get
973 },
974 #define CHANNELS_IDX 5
975 {
976         .access =       SNDRV_CTL_ELEM_ACCESS_READ,
977         .iface =        SNDRV_CTL_ELEM_IFACE_PCM,
978         .name =         "PCM Slave Channels",
979         .info =         loopback_channels_info,
980         .get =          loopback_channels_get
981 }
982 };
983
984 static int __devinit loopback_mixer_new(struct loopback *loopback, int notify)
985 {
986         struct snd_card *card = loopback->card;
987         struct snd_pcm *pcm;
988         struct snd_kcontrol *kctl;
989         struct loopback_setup *setup;
990         int err, dev, substr, substr_count, idx;
991
992         strcpy(card->mixername, "Loopback Mixer");
993         for (dev = 0; dev < 2; dev++) {
994                 pcm = loopback->pcm[dev];
995                 substr_count =
996                     pcm->streams[SNDRV_PCM_STREAM_CAPTURE].substream_count;
997                 for (substr = 0; substr < substr_count; substr++) {
998                         setup = &loopback->setup[substr][dev];
999                         setup->notify = notify;
1000                         setup->rate_shift = NO_PITCH;
1001                         setup->format = SNDRV_PCM_FORMAT_S16_LE;
1002                         setup->rate = 48000;
1003                         setup->channels = 2;
1004                         for (idx = 0; idx < ARRAY_SIZE(loopback_controls);
1005                                                                         idx++) {
1006                                 kctl = snd_ctl_new1(&loopback_controls[idx],
1007                                                     loopback);
1008                                 if (!kctl)
1009                                         return -ENOMEM;
1010                                 kctl->id.device = dev;
1011                                 kctl->id.subdevice = substr;
1012                                 switch (idx) {
1013                                 case ACTIVE_IDX:
1014                                         setup->active_id = kctl->id;
1015                                         break;
1016                                 case FORMAT_IDX:
1017                                         setup->format_id = kctl->id;
1018                                         break;
1019                                 case RATE_IDX:
1020                                         setup->rate_id = kctl->id;
1021                                         break;
1022                                 case CHANNELS_IDX:
1023                                         setup->channels_id = kctl->id;
1024                                         break;
1025                                 default:
1026                                         break;
1027                                 }
1028                                 err = snd_ctl_add(card, kctl);
1029                                 if (err < 0)
1030                                         return err;
1031                         }
1032                 }
1033         }
1034         return 0;
1035 }
1036
1037 #ifdef CONFIG_PROC_FS
1038
1039 static void print_dpcm_info(struct snd_info_buffer *buffer,
1040                             struct loopback_pcm *dpcm,
1041                             const char *id)
1042 {
1043         snd_iprintf(buffer, "  %s\n", id);
1044         if (dpcm == NULL) {
1045                 snd_iprintf(buffer, "    inactive\n");
1046                 return;
1047         }
1048         snd_iprintf(buffer, "    buffer_size:\t%u\n", dpcm->pcm_buffer_size);
1049         snd_iprintf(buffer, "    buffer_pos:\t\t%u\n", dpcm->buf_pos);
1050         snd_iprintf(buffer, "    silent_size:\t%u\n", dpcm->silent_size);
1051         snd_iprintf(buffer, "    period_size:\t%u\n", dpcm->pcm_period_size);
1052         snd_iprintf(buffer, "    bytes_per_sec:\t%u\n", dpcm->pcm_bps);
1053         snd_iprintf(buffer, "    sample_align:\t%u\n", dpcm->pcm_salign);
1054         snd_iprintf(buffer, "    rate_shift:\t\t%u\n", dpcm->pcm_rate_shift);
1055         snd_iprintf(buffer, "    update_pending:\t%u\n",
1056                                                 dpcm->period_update_pending);
1057         snd_iprintf(buffer, "    irq_pos:\t\t%u\n", dpcm->irq_pos);
1058         snd_iprintf(buffer, "    period_frac:\t%u\n", dpcm->period_size_frac);
1059         snd_iprintf(buffer, "    last_jiffies:\t%lu (%lu)\n",
1060                                         dpcm->last_jiffies, jiffies);
1061         snd_iprintf(buffer, "    timer_expires:\t%lu\n", dpcm->timer.expires);
1062 }
1063
1064 static void print_substream_info(struct snd_info_buffer *buffer,
1065                                  struct loopback *loopback,
1066                                  int sub,
1067                                  int num)
1068 {
1069         struct loopback_cable *cable = loopback->cables[sub][num];
1070
1071         snd_iprintf(buffer, "Cable %i substream %i:\n", num, sub);
1072         if (cable == NULL) {
1073                 snd_iprintf(buffer, "  inactive\n");
1074                 return;
1075         }
1076         snd_iprintf(buffer, "  valid: %u\n", cable->valid);
1077         snd_iprintf(buffer, "  running: %u\n", cable->running);
1078         snd_iprintf(buffer, "  pause: %u\n", cable->pause);
1079         print_dpcm_info(buffer, cable->streams[0], "Playback");
1080         print_dpcm_info(buffer, cable->streams[1], "Capture");
1081 }
1082
1083 static void print_cable_info(struct snd_info_entry *entry,
1084                              struct snd_info_buffer *buffer)
1085 {
1086         struct loopback *loopback = entry->private_data;
1087         int sub, num;
1088
1089         mutex_lock(&loopback->cable_lock);
1090         num = entry->name[strlen(entry->name)-1];
1091         num = num == '0' ? 0 : 1;
1092         for (sub = 0; sub < MAX_PCM_SUBSTREAMS; sub++)
1093                 print_substream_info(buffer, loopback, sub, num);
1094         mutex_unlock(&loopback->cable_lock);
1095 }
1096
1097 static int __devinit loopback_proc_new(struct loopback *loopback, int cidx)
1098 {
1099         char name[32];
1100         struct snd_info_entry *entry;
1101         int err;
1102
1103         snprintf(name, sizeof(name), "cable#%d", cidx);
1104         err = snd_card_proc_new(loopback->card, name, &entry);
1105         if (err < 0)
1106                 return err;
1107
1108         snd_info_set_text_ops(entry, loopback, print_cable_info);
1109         return 0;
1110 }
1111
1112 #else /* !CONFIG_PROC_FS */
1113
1114 #define loopback_proc_new(loopback, cidx) do { } while (0)
1115
1116 #endif
1117
1118 static int __devinit loopback_probe(struct platform_device *devptr)
1119 {
1120         struct snd_card *card;
1121         struct loopback *loopback;
1122         int dev = devptr->id;
1123         int err;
1124
1125         err = snd_card_create(index[dev], id[dev], THIS_MODULE,
1126                               sizeof(struct loopback), &card);
1127         if (err < 0)
1128                 return err;
1129         loopback = card->private_data;
1130
1131         if (pcm_substreams[dev] < 1)
1132                 pcm_substreams[dev] = 1;
1133         if (pcm_substreams[dev] > MAX_PCM_SUBSTREAMS)
1134                 pcm_substreams[dev] = MAX_PCM_SUBSTREAMS;
1135         
1136         loopback->card = card;
1137         mutex_init(&loopback->cable_lock);
1138
1139         err = loopback_pcm_new(loopback, 0, pcm_substreams[dev]);
1140         if (err < 0)
1141                 goto __nodev;
1142         err = loopback_pcm_new(loopback, 1, pcm_substreams[dev]);
1143         if (err < 0)
1144                 goto __nodev;
1145         err = loopback_mixer_new(loopback, pcm_notify[dev] ? 1 : 0);
1146         if (err < 0)
1147                 goto __nodev;
1148         loopback_proc_new(loopback, 0);
1149         loopback_proc_new(loopback, 1);
1150         strcpy(card->driver, "Loopback");
1151         strcpy(card->shortname, "Loopback");
1152         sprintf(card->longname, "Loopback %i", dev + 1);
1153         err = snd_card_register(card);
1154         if (!err) {
1155                 platform_set_drvdata(devptr, card);
1156                 return 0;
1157         }
1158       __nodev:
1159         snd_card_free(card);
1160         return err;
1161 }
1162
1163 static int __devexit loopback_remove(struct platform_device *devptr)
1164 {
1165         snd_card_free(platform_get_drvdata(devptr));
1166         platform_set_drvdata(devptr, NULL);
1167         return 0;
1168 }
1169
1170 #ifdef CONFIG_PM
1171 static int loopback_suspend(struct platform_device *pdev,
1172                                 pm_message_t state)
1173 {
1174         struct snd_card *card = platform_get_drvdata(pdev);
1175         struct loopback *loopback = card->private_data;
1176
1177         snd_power_change_state(card, SNDRV_CTL_POWER_D3hot);
1178
1179         snd_pcm_suspend_all(loopback->pcm[0]);
1180         snd_pcm_suspend_all(loopback->pcm[1]);
1181         return 0;
1182 }
1183         
1184 static int loopback_resume(struct platform_device *pdev)
1185 {
1186         struct snd_card *card = platform_get_drvdata(pdev);
1187
1188         snd_power_change_state(card, SNDRV_CTL_POWER_D0);
1189         return 0;
1190 }
1191 #endif
1192
1193 #define SND_LOOPBACK_DRIVER     "snd_aloop"
1194
1195 static struct platform_driver loopback_driver = {
1196         .probe          = loopback_probe,
1197         .remove         = __devexit_p(loopback_remove),
1198 #ifdef CONFIG_PM
1199         .suspend        = loopback_suspend,
1200         .resume         = loopback_resume,
1201 #endif
1202         .driver         = {
1203                 .name   = SND_LOOPBACK_DRIVER
1204         },
1205 };
1206
1207 static void loopback_unregister_all(void)
1208 {
1209         int i;
1210
1211         for (i = 0; i < ARRAY_SIZE(devices); ++i)
1212                 platform_device_unregister(devices[i]);
1213         platform_driver_unregister(&loopback_driver);
1214 }
1215
1216 static int __init alsa_card_loopback_init(void)
1217 {
1218         int i, err, cards;
1219
1220         err = platform_driver_register(&loopback_driver);
1221         if (err < 0)
1222                 return err;
1223
1224
1225         cards = 0;
1226         for (i = 0; i < SNDRV_CARDS; i++) {
1227                 struct platform_device *device;
1228                 if (!enable[i])
1229                         continue;
1230                 device = platform_device_register_simple(SND_LOOPBACK_DRIVER,
1231                                                          i, NULL, 0);
1232                 if (IS_ERR(device))
1233                         continue;
1234                 if (!platform_get_drvdata(device)) {
1235                         platform_device_unregister(device);
1236                         continue;
1237                 }
1238                 devices[i] = device;
1239                 cards++;
1240         }
1241         if (!cards) {
1242 #ifdef MODULE
1243                 printk(KERN_ERR "aloop: No loopback enabled\n");
1244 #endif
1245                 loopback_unregister_all();
1246                 return -ENODEV;
1247         }
1248         return 0;
1249 }
1250
1251 static void __exit alsa_card_loopback_exit(void)
1252 {
1253         loopback_unregister_all();
1254 }
1255
1256 module_init(alsa_card_loopback_init)
1257 module_exit(alsa_card_loopback_exit)