12b44b0b677712642a57be2f5554a4fb86347f2a
[linux-2.6.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
486         spin_lock(&cable->lock);        
487         running = cable->running ^ cable->pause;
488         if (running & (1 << SNDRV_PCM_STREAM_PLAYBACK)) {
489                 delta_play = jiffies - dpcm_play->last_jiffies;
490                 dpcm_play->last_jiffies += delta_play;
491         }
492
493         if (running & (1 << SNDRV_PCM_STREAM_CAPTURE)) {
494                 delta_capt = jiffies - dpcm_capt->last_jiffies;
495                 dpcm_capt->last_jiffies += delta_capt;
496         }
497
498         if (delta_play == 0 && delta_capt == 0) {
499                 spin_unlock(&cable->lock);
500                 return running;
501         }
502                 
503         if (delta_play > delta_capt) {
504                 loopback_bytepos_update(dpcm_play, delta_play - delta_capt,
505                                         BYTEPOS_UPDATE_POSONLY);
506                 delta_play = delta_capt;
507         } else if (delta_play < delta_capt) {
508                 loopback_bytepos_update(dpcm_capt, delta_capt - delta_play,
509                                         BYTEPOS_UPDATE_CLEAR);
510                 delta_capt = delta_play;
511         }
512
513         if (delta_play == 0 && delta_capt == 0) {
514                 spin_unlock(&cable->lock);
515                 return running;
516         }
517         /* note delta_capt == delta_play at this moment */
518         loopback_bytepos_update(dpcm_capt, delta_capt, BYTEPOS_UPDATE_COPY);
519         loopback_bytepos_update(dpcm_play, delta_play, BYTEPOS_UPDATE_POSONLY);
520         spin_unlock(&cable->lock);
521         return running;
522 }
523
524 static void loopback_timer_function(unsigned long data)
525 {
526         struct loopback_pcm *dpcm = (struct loopback_pcm *)data;
527         unsigned int running;
528
529         running = loopback_pos_update(dpcm->cable);
530         if (running & (1 << dpcm->substream->stream)) {
531                 loopback_timer_start(dpcm);
532                 if (dpcm->period_update_pending) {
533                         dpcm->period_update_pending = 0;
534                         snd_pcm_period_elapsed(dpcm->substream);
535                 }
536         }
537 }
538
539 static snd_pcm_uframes_t loopback_pointer(struct snd_pcm_substream *substream)
540 {
541         struct snd_pcm_runtime *runtime = substream->runtime;
542         struct loopback_pcm *dpcm = runtime->private_data;
543
544         loopback_pos_update(dpcm->cable);
545         return bytes_to_frames(runtime, dpcm->buf_pos);
546 }
547
548 static struct snd_pcm_hardware loopback_pcm_hardware =
549 {
550         .info =         (SNDRV_PCM_INFO_INTERLEAVED | SNDRV_PCM_INFO_MMAP |
551                          SNDRV_PCM_INFO_MMAP_VALID | SNDRV_PCM_INFO_PAUSE),
552         .formats =      (SNDRV_PCM_FMTBIT_S16_LE | SNDRV_PCM_FMTBIT_S16_BE |
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_malloc_pages(substream, params_buffer_bytes(params));
580 }
581
582 static int loopback_hw_free(struct snd_pcm_substream *substream)
583 {
584         struct snd_pcm_runtime *runtime = substream->runtime;
585         struct loopback_pcm *dpcm = runtime->private_data;
586         struct loopback_cable *cable = dpcm->cable;
587
588         mutex_lock(&dpcm->loopback->cable_lock);
589         cable->valid &= ~(1 << substream->stream);
590         mutex_unlock(&dpcm->loopback->cable_lock);
591         return snd_pcm_lib_free_pages(substream);
592 }
593
594 static unsigned int get_cable_index(struct snd_pcm_substream *substream)
595 {
596         if (!substream->pcm->device)
597                 return substream->stream;
598         else
599                 return !substream->stream;
600 }
601
602 static int rule_format(struct snd_pcm_hw_params *params,
603                        struct snd_pcm_hw_rule *rule)
604 {
605
606         struct snd_pcm_hardware *hw = rule->private;
607         struct snd_mask *maskp = hw_param_mask(params, rule->var);
608
609         maskp->bits[0] &= (u_int32_t)hw->formats;
610         maskp->bits[1] &= (u_int32_t)(hw->formats >> 32);
611         memset(maskp->bits + 2, 0, (SNDRV_MASK_MAX-64) / 8); /* clear rest */
612         if (! maskp->bits[0] && ! maskp->bits[1])
613                 return -EINVAL;
614         return 0;
615 }
616
617 static int rule_rate(struct snd_pcm_hw_params *params,
618                      struct snd_pcm_hw_rule *rule)
619 {
620         struct snd_pcm_hardware *hw = rule->private;
621         struct snd_interval t;
622
623         t.min = hw->rate_min;
624         t.max = hw->rate_max;
625         t.openmin = t.openmax = 0;
626         t.integer = 0;
627         return snd_interval_refine(hw_param_interval(params, rule->var), &t);
628 }
629
630 static int rule_channels(struct snd_pcm_hw_params *params,
631                          struct snd_pcm_hw_rule *rule)
632 {
633         struct snd_pcm_hardware *hw = rule->private;
634         struct snd_interval t;
635
636         t.min = hw->channels_min;
637         t.max = hw->channels_max;
638         t.openmin = t.openmax = 0;
639         t.integer = 0;
640         return snd_interval_refine(hw_param_interval(params, rule->var), &t);
641 }
642
643 static int loopback_open(struct snd_pcm_substream *substream)
644 {
645         struct snd_pcm_runtime *runtime = substream->runtime;
646         struct loopback *loopback = substream->private_data;
647         struct loopback_pcm *dpcm;
648         struct loopback_cable *cable;
649         int err = 0;
650         int dev = get_cable_index(substream);
651
652         mutex_lock(&loopback->cable_lock);
653         dpcm = kzalloc(sizeof(*dpcm), GFP_KERNEL);
654         if (!dpcm) {
655                 err = -ENOMEM;
656                 goto unlock;
657         }
658         dpcm->loopback = loopback;
659         dpcm->substream = substream;
660         setup_timer(&dpcm->timer, loopback_timer_function,
661                     (unsigned long)dpcm);
662
663         cable = loopback->cables[substream->number][dev];
664         if (!cable) {
665                 cable = kzalloc(sizeof(*cable), GFP_KERNEL);
666                 if (!cable) {
667                         kfree(dpcm);
668                         err = -ENOMEM;
669                         goto unlock;
670                 }
671                 spin_lock_init(&cable->lock);
672                 cable->hw = loopback_pcm_hardware;
673                 loopback->cables[substream->number][dev] = cable;
674         }
675         dpcm->cable = cable;
676         cable->streams[substream->stream] = dpcm;
677
678         snd_pcm_hw_constraint_integer(runtime, SNDRV_PCM_HW_PARAM_PERIODS);
679
680         /* use dynamic rules based on actual runtime->hw values */
681         /* note that the default rules created in the PCM midlevel code */
682         /* are cached -> they do not reflect the actual state */
683         err = snd_pcm_hw_rule_add(runtime, 0,
684                                   SNDRV_PCM_HW_PARAM_FORMAT,
685                                   rule_format, &runtime->hw,
686                                   SNDRV_PCM_HW_PARAM_FORMAT, -1);
687         if (err < 0)
688                 goto unlock;
689         err = snd_pcm_hw_rule_add(runtime, 0,
690                                   SNDRV_PCM_HW_PARAM_RATE,
691                                   rule_rate, &runtime->hw,
692                                   SNDRV_PCM_HW_PARAM_RATE, -1);
693         if (err < 0)
694                 goto unlock;
695         err = snd_pcm_hw_rule_add(runtime, 0,
696                                   SNDRV_PCM_HW_PARAM_CHANNELS,
697                                   rule_channels, &runtime->hw,
698                                   SNDRV_PCM_HW_PARAM_CHANNELS, -1);
699         if (err < 0)
700                 goto unlock;
701
702         runtime->private_data = dpcm;
703         runtime->private_free = loopback_runtime_free;
704         if (get_notify(dpcm))
705                 runtime->hw = loopback_pcm_hardware;
706         else
707                 runtime->hw = cable->hw;
708  unlock:
709         mutex_unlock(&loopback->cable_lock);
710         return err;
711 }
712
713 static int loopback_close(struct snd_pcm_substream *substream)
714 {
715         struct loopback *loopback = substream->private_data;
716         struct loopback_pcm *dpcm = substream->runtime->private_data;
717         struct loopback_cable *cable;
718         int dev = get_cable_index(substream);
719
720         loopback_timer_stop(dpcm);
721         mutex_lock(&loopback->cable_lock);
722         cable = loopback->cables[substream->number][dev];
723         if (cable->streams[!substream->stream]) {
724                 /* other stream is still alive */
725                 cable->streams[substream->stream] = NULL;
726         } else {
727                 /* free the cable */
728                 loopback->cables[substream->number][dev] = NULL;
729                 kfree(cable);
730         }
731         mutex_unlock(&loopback->cable_lock);
732         return 0;
733 }
734
735 static struct snd_pcm_ops loopback_playback_ops = {
736         .open =         loopback_open,
737         .close =        loopback_close,
738         .ioctl =        snd_pcm_lib_ioctl,
739         .hw_params =    loopback_hw_params,
740         .hw_free =      loopback_hw_free,
741         .prepare =      loopback_prepare,
742         .trigger =      loopback_trigger,
743         .pointer =      loopback_pointer,
744 };
745
746 static struct snd_pcm_ops loopback_capture_ops = {
747         .open =         loopback_open,
748         .close =        loopback_close,
749         .ioctl =        snd_pcm_lib_ioctl,
750         .hw_params =    loopback_hw_params,
751         .hw_free =      loopback_hw_free,
752         .prepare =      loopback_prepare,
753         .trigger =      loopback_trigger,
754         .pointer =      loopback_pointer,
755 };
756
757 static int __devinit loopback_pcm_new(struct loopback *loopback,
758                                       int device, int substreams)
759 {
760         struct snd_pcm *pcm;
761         int err;
762
763         err = snd_pcm_new(loopback->card, "Loopback PCM", device,
764                           substreams, substreams, &pcm);
765         if (err < 0)
766                 return err;
767         snd_pcm_set_ops(pcm, SNDRV_PCM_STREAM_PLAYBACK, &loopback_playback_ops);
768         snd_pcm_set_ops(pcm, SNDRV_PCM_STREAM_CAPTURE, &loopback_capture_ops);
769
770         pcm->private_data = loopback;
771         pcm->info_flags = 0;
772         strcpy(pcm->name, "Loopback PCM");
773
774         loopback->pcm[device] = pcm;
775
776         snd_pcm_lib_preallocate_pages_for_all(pcm, SNDRV_DMA_TYPE_CONTINUOUS,
777                         snd_dma_continuous_data(GFP_KERNEL),
778                         0, 2 * 1024 * 1024);
779         return 0;
780 }
781
782 static int loopback_rate_shift_info(struct snd_kcontrol *kcontrol,   
783                                     struct snd_ctl_elem_info *uinfo) 
784 {
785         uinfo->type = SNDRV_CTL_ELEM_TYPE_INTEGER;
786         uinfo->count = 1;
787         uinfo->value.integer.min = 80000;
788         uinfo->value.integer.max = 120000;
789         uinfo->value.integer.step = 1;
790         return 0;
791 }                                  
792
793 static int loopback_rate_shift_get(struct snd_kcontrol *kcontrol,
794                                    struct snd_ctl_elem_value *ucontrol)
795 {
796         struct loopback *loopback = snd_kcontrol_chip(kcontrol);
797         
798         ucontrol->value.integer.value[0] =
799                 loopback->setup[kcontrol->id.subdevice]
800                                [kcontrol->id.device].rate_shift;
801         return 0;
802 }
803
804 static int loopback_rate_shift_put(struct snd_kcontrol *kcontrol,
805                                    struct snd_ctl_elem_value *ucontrol)
806 {
807         struct loopback *loopback = snd_kcontrol_chip(kcontrol);
808         unsigned int val;
809         int change = 0;
810
811         val = ucontrol->value.integer.value[0];
812         if (val < 80000)
813                 val = 80000;
814         if (val > 120000)
815                 val = 120000;   
816         mutex_lock(&loopback->cable_lock);
817         if (val != loopback->setup[kcontrol->id.subdevice]
818                                   [kcontrol->id.device].rate_shift) {
819                 loopback->setup[kcontrol->id.subdevice]
820                                [kcontrol->id.device].rate_shift = val;
821                 change = 1;
822         }
823         mutex_unlock(&loopback->cable_lock);
824         return change;
825 }
826
827 static int loopback_notify_get(struct snd_kcontrol *kcontrol,
828                                struct snd_ctl_elem_value *ucontrol)
829 {
830         struct loopback *loopback = snd_kcontrol_chip(kcontrol);
831         
832         ucontrol->value.integer.value[0] =
833                 loopback->setup[kcontrol->id.subdevice]
834                                [kcontrol->id.device].notify;
835         return 0;
836 }
837
838 static int loopback_notify_put(struct snd_kcontrol *kcontrol,
839                                struct snd_ctl_elem_value *ucontrol)
840 {
841         struct loopback *loopback = snd_kcontrol_chip(kcontrol);
842         unsigned int val;
843         int change = 0;
844
845         val = ucontrol->value.integer.value[0] ? 1 : 0;
846         if (val != loopback->setup[kcontrol->id.subdevice]
847                                 [kcontrol->id.device].notify) {
848                 loopback->setup[kcontrol->id.subdevice]
849                         [kcontrol->id.device].notify = val;
850                 change = 1;
851         }
852         return change;
853 }
854
855 static int loopback_active_get(struct snd_kcontrol *kcontrol,
856                                struct snd_ctl_elem_value *ucontrol)
857 {
858         struct loopback *loopback = snd_kcontrol_chip(kcontrol);
859         struct loopback_cable *cable = loopback->cables
860                         [kcontrol->id.subdevice][kcontrol->id.device ^ 1];
861         unsigned int val = 0;
862
863         if (cable != NULL)
864                 val = (cable->running & (1 << SNDRV_PCM_STREAM_PLAYBACK)) ?
865                                                                         1 : 0;
866         ucontrol->value.integer.value[0] = val;
867         return 0;
868 }
869
870 static int loopback_format_info(struct snd_kcontrol *kcontrol,   
871                                 struct snd_ctl_elem_info *uinfo) 
872 {
873         uinfo->type = SNDRV_CTL_ELEM_TYPE_INTEGER;
874         uinfo->count = 1;
875         uinfo->value.integer.min = 0;
876         uinfo->value.integer.max = SNDRV_PCM_FORMAT_LAST;
877         uinfo->value.integer.step = 1;
878         return 0;
879 }                                  
880
881 static int loopback_format_get(struct snd_kcontrol *kcontrol,
882                                struct snd_ctl_elem_value *ucontrol)
883 {
884         struct loopback *loopback = snd_kcontrol_chip(kcontrol);
885         
886         ucontrol->value.integer.value[0] =
887                 loopback->setup[kcontrol->id.subdevice]
888                                [kcontrol->id.device].format;
889         return 0;
890 }
891
892 static int loopback_rate_info(struct snd_kcontrol *kcontrol,   
893                               struct snd_ctl_elem_info *uinfo) 
894 {
895         uinfo->type = SNDRV_CTL_ELEM_TYPE_INTEGER;
896         uinfo->count = 1;
897         uinfo->value.integer.min = 0;
898         uinfo->value.integer.max = 192000;
899         uinfo->value.integer.step = 1;
900         return 0;
901 }                                  
902
903 static int loopback_rate_get(struct snd_kcontrol *kcontrol,
904                              struct snd_ctl_elem_value *ucontrol)
905 {
906         struct loopback *loopback = snd_kcontrol_chip(kcontrol);
907         
908         ucontrol->value.integer.value[0] =
909                 loopback->setup[kcontrol->id.subdevice]
910                                [kcontrol->id.device].rate;
911         return 0;
912 }
913
914 static int loopback_channels_info(struct snd_kcontrol *kcontrol,   
915                                   struct snd_ctl_elem_info *uinfo) 
916 {
917         uinfo->type = SNDRV_CTL_ELEM_TYPE_INTEGER;
918         uinfo->count = 1;
919         uinfo->value.integer.min = 1;
920         uinfo->value.integer.max = 1024;
921         uinfo->value.integer.step = 1;
922         return 0;
923 }                                  
924
925 static int loopback_channels_get(struct snd_kcontrol *kcontrol,
926                                  struct snd_ctl_elem_value *ucontrol)
927 {
928         struct loopback *loopback = snd_kcontrol_chip(kcontrol);
929         
930         ucontrol->value.integer.value[0] =
931                 loopback->setup[kcontrol->id.subdevice]
932                                [kcontrol->id.device].channels;
933         return 0;
934 }
935
936 static struct snd_kcontrol_new loopback_controls[]  __devinitdata = {
937 {
938         .iface =        SNDRV_CTL_ELEM_IFACE_PCM,
939         .name =         "PCM Rate Shift 100000",
940         .info =         loopback_rate_shift_info,
941         .get =          loopback_rate_shift_get,
942         .put =          loopback_rate_shift_put,
943 },
944 {
945         .iface =        SNDRV_CTL_ELEM_IFACE_PCM,
946         .name =         "PCM Notify",
947         .info =         snd_ctl_boolean_mono_info,
948         .get =          loopback_notify_get,
949         .put =          loopback_notify_put,
950 },
951 #define ACTIVE_IDX 2
952 {
953         .access =       SNDRV_CTL_ELEM_ACCESS_READ,
954         .iface =        SNDRV_CTL_ELEM_IFACE_PCM,
955         .name =         "PCM Slave Active",
956         .info =         snd_ctl_boolean_mono_info,
957         .get =          loopback_active_get,
958 },
959 #define FORMAT_IDX 3
960 {
961         .access =       SNDRV_CTL_ELEM_ACCESS_READ,
962         .iface =        SNDRV_CTL_ELEM_IFACE_PCM,
963         .name =         "PCM Slave Format",
964         .info =         loopback_format_info,
965         .get =          loopback_format_get
966 },
967 #define RATE_IDX 4
968 {
969         .access =       SNDRV_CTL_ELEM_ACCESS_READ,
970         .iface =        SNDRV_CTL_ELEM_IFACE_PCM,
971         .name =         "PCM Slave Rate",
972         .info =         loopback_rate_info,
973         .get =          loopback_rate_get
974 },
975 #define CHANNELS_IDX 5
976 {
977         .access =       SNDRV_CTL_ELEM_ACCESS_READ,
978         .iface =        SNDRV_CTL_ELEM_IFACE_PCM,
979         .name =         "PCM Slave Channels",
980         .info =         loopback_channels_info,
981         .get =          loopback_channels_get
982 }
983 };
984
985 static int __devinit loopback_mixer_new(struct loopback *loopback, int notify)
986 {
987         struct snd_card *card = loopback->card;
988         struct snd_pcm *pcm;
989         struct snd_kcontrol *kctl;
990         struct loopback_setup *setup;
991         int err, dev, substr, substr_count, idx;
992
993         strcpy(card->mixername, "Loopback Mixer");
994         for (dev = 0; dev < 2; dev++) {
995                 pcm = loopback->pcm[dev];
996                 substr_count =
997                     pcm->streams[SNDRV_PCM_STREAM_CAPTURE].substream_count;
998                 for (substr = 0; substr < substr_count; substr++) {
999                         setup = &loopback->setup[substr][dev];
1000                         setup->notify = notify;
1001                         setup->rate_shift = NO_PITCH;
1002                         setup->format = SNDRV_PCM_FORMAT_S16_LE;
1003                         setup->rate = 48000;
1004                         setup->channels = 2;
1005                         for (idx = 0; idx < ARRAY_SIZE(loopback_controls);
1006                                                                         idx++) {
1007                                 kctl = snd_ctl_new1(&loopback_controls[idx],
1008                                                     loopback);
1009                                 if (!kctl)
1010                                         return -ENOMEM;
1011                                 kctl->id.device = dev;
1012                                 kctl->id.subdevice = substr;
1013                                 switch (idx) {
1014                                 case ACTIVE_IDX:
1015                                         setup->active_id = kctl->id;
1016                                         break;
1017                                 case FORMAT_IDX:
1018                                         setup->format_id = kctl->id;
1019                                         break;
1020                                 case RATE_IDX:
1021                                         setup->rate_id = kctl->id;
1022                                         break;
1023                                 case CHANNELS_IDX:
1024                                         setup->channels_id = kctl->id;
1025                                         break;
1026                                 default:
1027                                         break;
1028                                 }
1029                                 err = snd_ctl_add(card, kctl);
1030                                 if (err < 0)
1031                                         return err;
1032                         }
1033                 }
1034         }
1035         return 0;
1036 }
1037
1038 #ifdef CONFIG_PROC_FS
1039
1040 static void print_dpcm_info(struct snd_info_buffer *buffer,
1041                             struct loopback_pcm *dpcm,
1042                             const char *id)
1043 {
1044         snd_iprintf(buffer, "  %s\n", id);
1045         if (dpcm == NULL) {
1046                 snd_iprintf(buffer, "    inactive\n");
1047                 return;
1048         }
1049         snd_iprintf(buffer, "    buffer_size:\t%u\n", dpcm->pcm_buffer_size);
1050         snd_iprintf(buffer, "    buffer_pos:\t\t%u\n", dpcm->buf_pos);
1051         snd_iprintf(buffer, "    silent_size:\t%u\n", dpcm->silent_size);
1052         snd_iprintf(buffer, "    period_size:\t%u\n", dpcm->pcm_period_size);
1053         snd_iprintf(buffer, "    bytes_per_sec:\t%u\n", dpcm->pcm_bps);
1054         snd_iprintf(buffer, "    sample_align:\t%u\n", dpcm->pcm_salign);
1055         snd_iprintf(buffer, "    rate_shift:\t\t%u\n", dpcm->pcm_rate_shift);
1056         snd_iprintf(buffer, "    update_pending:\t%u\n",
1057                                                 dpcm->period_update_pending);
1058         snd_iprintf(buffer, "    irq_pos:\t\t%u\n", dpcm->irq_pos);
1059         snd_iprintf(buffer, "    period_frac:\t%u\n", dpcm->period_size_frac);
1060         snd_iprintf(buffer, "    last_jiffies:\t%lu (%lu)\n",
1061                                         dpcm->last_jiffies, jiffies);
1062         snd_iprintf(buffer, "    timer_expires:\t%lu\n", dpcm->timer.expires);
1063 }
1064
1065 static void print_substream_info(struct snd_info_buffer *buffer,
1066                                  struct loopback *loopback,
1067                                  int sub,
1068                                  int num)
1069 {
1070         struct loopback_cable *cable = loopback->cables[sub][num];
1071
1072         snd_iprintf(buffer, "Cable %i substream %i:\n", num, sub);
1073         if (cable == NULL) {
1074                 snd_iprintf(buffer, "  inactive\n");
1075                 return;
1076         }
1077         snd_iprintf(buffer, "  valid: %u\n", cable->valid);
1078         snd_iprintf(buffer, "  running: %u\n", cable->running);
1079         snd_iprintf(buffer, "  pause: %u\n", cable->pause);
1080         print_dpcm_info(buffer, cable->streams[0], "Playback");
1081         print_dpcm_info(buffer, cable->streams[1], "Capture");
1082 }
1083
1084 static void print_cable_info(struct snd_info_entry *entry,
1085                              struct snd_info_buffer *buffer)
1086 {
1087         struct loopback *loopback = entry->private_data;
1088         int sub, num;
1089
1090         mutex_lock(&loopback->cable_lock);
1091         num = entry->name[strlen(entry->name)-1];
1092         num = num == '0' ? 0 : 1;
1093         for (sub = 0; sub < MAX_PCM_SUBSTREAMS; sub++)
1094                 print_substream_info(buffer, loopback, sub, num);
1095         mutex_unlock(&loopback->cable_lock);
1096 }
1097
1098 static int __devinit loopback_proc_new(struct loopback *loopback, int cidx)
1099 {
1100         char name[32];
1101         struct snd_info_entry *entry;
1102         int err;
1103
1104         snprintf(name, sizeof(name), "cable#%d", cidx);
1105         err = snd_card_proc_new(loopback->card, name, &entry);
1106         if (err < 0)
1107                 return err;
1108
1109         snd_info_set_text_ops(entry, loopback, print_cable_info);
1110         return 0;
1111 }
1112
1113 #else /* !CONFIG_PROC_FS */
1114
1115 #define loopback_proc_new(loopback, cidx) do { } while (0)
1116
1117 #endif
1118
1119 static int __devinit loopback_probe(struct platform_device *devptr)
1120 {
1121         struct snd_card *card;
1122         struct loopback *loopback;
1123         int dev = devptr->id;
1124         int err;
1125
1126         err = snd_card_create(index[dev], id[dev], THIS_MODULE,
1127                               sizeof(struct loopback), &card);
1128         if (err < 0)
1129                 return err;
1130         loopback = card->private_data;
1131
1132         if (pcm_substreams[dev] < 1)
1133                 pcm_substreams[dev] = 1;
1134         if (pcm_substreams[dev] > MAX_PCM_SUBSTREAMS)
1135                 pcm_substreams[dev] = MAX_PCM_SUBSTREAMS;
1136         
1137         loopback->card = card;
1138         mutex_init(&loopback->cable_lock);
1139
1140         err = loopback_pcm_new(loopback, 0, pcm_substreams[dev]);
1141         if (err < 0)
1142                 goto __nodev;
1143         err = loopback_pcm_new(loopback, 1, pcm_substreams[dev]);
1144         if (err < 0)
1145                 goto __nodev;
1146         err = loopback_mixer_new(loopback, pcm_notify[dev] ? 1 : 0);
1147         if (err < 0)
1148                 goto __nodev;
1149         loopback_proc_new(loopback, 0);
1150         loopback_proc_new(loopback, 1);
1151         strcpy(card->driver, "Loopback");
1152         strcpy(card->shortname, "Loopback");
1153         sprintf(card->longname, "Loopback %i", dev + 1);
1154         err = snd_card_register(card);
1155         if (!err) {
1156                 platform_set_drvdata(devptr, card);
1157                 return 0;
1158         }
1159       __nodev:
1160         snd_card_free(card);
1161         return err;
1162 }
1163
1164 static int __devexit loopback_remove(struct platform_device *devptr)
1165 {
1166         snd_card_free(platform_get_drvdata(devptr));
1167         platform_set_drvdata(devptr, NULL);
1168         return 0;
1169 }
1170
1171 #ifdef CONFIG_PM
1172 static int loopback_suspend(struct platform_device *pdev,
1173                                 pm_message_t state)
1174 {
1175         struct snd_card *card = platform_get_drvdata(pdev);
1176         struct loopback *loopback = card->private_data;
1177
1178         snd_power_change_state(card, SNDRV_CTL_POWER_D3hot);
1179
1180         snd_pcm_suspend_all(loopback->pcm[0]);
1181         snd_pcm_suspend_all(loopback->pcm[1]);
1182         return 0;
1183 }
1184         
1185 static int loopback_resume(struct platform_device *pdev)
1186 {
1187         struct snd_card *card = platform_get_drvdata(pdev);
1188
1189         snd_power_change_state(card, SNDRV_CTL_POWER_D0);
1190         return 0;
1191 }
1192 #endif
1193
1194 #define SND_LOOPBACK_DRIVER     "snd_aloop"
1195
1196 static struct platform_driver loopback_driver = {
1197         .probe          = loopback_probe,
1198         .remove         = __devexit_p(loopback_remove),
1199 #ifdef CONFIG_PM
1200         .suspend        = loopback_suspend,
1201         .resume         = loopback_resume,
1202 #endif
1203         .driver         = {
1204                 .name   = SND_LOOPBACK_DRIVER
1205         },
1206 };
1207
1208 static void loopback_unregister_all(void)
1209 {
1210         int i;
1211
1212         for (i = 0; i < ARRAY_SIZE(devices); ++i)
1213                 platform_device_unregister(devices[i]);
1214         platform_driver_unregister(&loopback_driver);
1215 }
1216
1217 static int __init alsa_card_loopback_init(void)
1218 {
1219         int i, err, cards;
1220
1221         err = platform_driver_register(&loopback_driver);
1222         if (err < 0)
1223                 return err;
1224
1225
1226         cards = 0;
1227         for (i = 0; i < SNDRV_CARDS; i++) {
1228                 struct platform_device *device;
1229                 if (!enable[i])
1230                         continue;
1231                 device = platform_device_register_simple(SND_LOOPBACK_DRIVER,
1232                                                          i, NULL, 0);
1233                 if (IS_ERR(device))
1234                         continue;
1235                 if (!platform_get_drvdata(device)) {
1236                         platform_device_unregister(device);
1237                         continue;
1238                 }
1239                 devices[i] = device;
1240                 cards++;
1241         }
1242         if (!cards) {
1243 #ifdef MODULE
1244                 printk(KERN_ERR "aloop: No loopback enabled\n");
1245 #endif
1246                 loopback_unregister_all();
1247                 return -ENODEV;
1248         }
1249         return 0;
1250 }
1251
1252 static void __exit alsa_card_loopback_exit(void)
1253 {
1254         loopback_unregister_all();
1255 }
1256
1257 module_init(alsa_card_loopback_init)
1258 module_exit(alsa_card_loopback_exit)