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