6408932f5f7251bdac6ddb98edb8a6abd176da4e
[sfrench/cifs-2.6.git] / sound / drivers / aloop.c
1 // SPDX-License-Identifier: GPL-2.0-or-later
2 /*
3  *  Loopback soundcard
4  *
5  *  Original code:
6  *  Copyright (c) by Jaroslav Kysela <perex@perex.cz>
7  *
8  *  More accurate positioning and full-duplex support:
9  *  Copyright (c) Ahmet ─░nan <ainan at mathematik.uni-freiburg.de>
10  *
11  *  Major (almost complete) rewrite:
12  *  Copyright (c) by Takashi Iwai <tiwai@suse.de>
13  *
14  *  A next major update in 2010 (separate timers for playback and capture):
15  *  Copyright (c) Jaroslav Kysela <perex@perex.cz>
16  */
17
18 #include <linux/init.h>
19 #include <linux/jiffies.h>
20 #include <linux/slab.h>
21 #include <linux/time.h>
22 #include <linux/wait.h>
23 #include <linux/module.h>
24 #include <linux/platform_device.h>
25 #include <sound/core.h>
26 #include <sound/control.h>
27 #include <sound/pcm.h>
28 #include <sound/pcm_params.h>
29 #include <sound/info.h>
30 #include <sound/initval.h>
31 #include <sound/timer.h>
32
33 MODULE_AUTHOR("Jaroslav Kysela <perex@perex.cz>");
34 MODULE_DESCRIPTION("A loopback soundcard");
35 MODULE_LICENSE("GPL");
36 MODULE_SUPPORTED_DEVICE("{{ALSA,Loopback soundcard}}");
37
38 #define MAX_PCM_SUBSTREAMS      8
39
40 static int index[SNDRV_CARDS] = SNDRV_DEFAULT_IDX;      /* Index 0-MAX */
41 static char *id[SNDRV_CARDS] = SNDRV_DEFAULT_STR;       /* ID for this card */
42 static bool enable[SNDRV_CARDS] = {1, [1 ... (SNDRV_CARDS - 1)] = 0};
43 static int pcm_substreams[SNDRV_CARDS] = {[0 ... (SNDRV_CARDS - 1)] = 8};
44 static int pcm_notify[SNDRV_CARDS];
45 static char *timer_source[SNDRV_CARDS];
46
47 module_param_array(index, int, NULL, 0444);
48 MODULE_PARM_DESC(index, "Index value for loopback soundcard.");
49 module_param_array(id, charp, NULL, 0444);
50 MODULE_PARM_DESC(id, "ID string for loopback soundcard.");
51 module_param_array(enable, bool, NULL, 0444);
52 MODULE_PARM_DESC(enable, "Enable this loopback soundcard.");
53 module_param_array(pcm_substreams, int, NULL, 0444);
54 MODULE_PARM_DESC(pcm_substreams, "PCM substreams # (1-8) for loopback driver.");
55 module_param_array(pcm_notify, int, NULL, 0444);
56 MODULE_PARM_DESC(pcm_notify, "Break capture when PCM format/rate/channels changes.");
57 module_param_array(timer_source, charp, NULL, 0444);
58 MODULE_PARM_DESC(timer_source, "Sound card name or number and device/subdevice number of timer to be used. Empty string for jiffies timer [default].");
59
60 #define NO_PITCH 100000
61
62 #define CABLE_VALID_PLAYBACK    BIT(SNDRV_PCM_STREAM_PLAYBACK)
63 #define CABLE_VALID_CAPTURE     BIT(SNDRV_PCM_STREAM_CAPTURE)
64 #define CABLE_VALID_BOTH        (CABLE_VALID_PLAYBACK | CABLE_VALID_CAPTURE)
65
66 struct loopback_cable;
67 struct loopback_pcm;
68
69 struct loopback_ops {
70         /* optional
71          * call in loopback->cable_lock
72          */
73         int (*open)(struct loopback_pcm *dpcm);
74         /* required
75          * call in cable->lock
76          */
77         int (*start)(struct loopback_pcm *dpcm);
78         /* required
79          * call in cable->lock
80          */
81         int (*stop)(struct loopback_pcm *dpcm);
82         /* optional */
83         int (*stop_sync)(struct loopback_pcm *dpcm);
84         /* optional */
85         int (*close_substream)(struct loopback_pcm *dpcm);
86         /* optional
87          * call in loopback->cable_lock
88          */
89         int (*close_cable)(struct loopback_pcm *dpcm);
90         /* optional
91          * call in cable->lock
92          */
93         unsigned int (*pos_update)(struct loopback_cable *cable);
94         /* optional */
95         void (*dpcm_info)(struct loopback_pcm *dpcm,
96                           struct snd_info_buffer *buffer);
97 };
98
99 struct loopback_cable {
100         spinlock_t lock;
101         struct loopback_pcm *streams[2];
102         struct snd_pcm_hardware hw;
103         /* flags */
104         unsigned int valid;
105         unsigned int running;
106         unsigned int pause;
107         /* timer specific */
108         struct loopback_ops *ops;
109         /* If sound timer is used */
110         struct {
111                 int stream;
112                 struct snd_timer_id id;
113                 struct tasklet_struct event_tasklet;
114                 struct snd_timer_instance *instance;
115         } snd_timer;
116 };
117
118 struct loopback_setup {
119         unsigned int notify: 1;
120         unsigned int rate_shift;
121         unsigned int format;
122         unsigned int rate;
123         unsigned int channels;
124         struct snd_ctl_elem_id active_id;
125         struct snd_ctl_elem_id format_id;
126         struct snd_ctl_elem_id rate_id;
127         struct snd_ctl_elem_id channels_id;
128 };
129
130 struct loopback {
131         struct snd_card *card;
132         struct mutex cable_lock;
133         struct loopback_cable *cables[MAX_PCM_SUBSTREAMS][2];
134         struct snd_pcm *pcm[2];
135         struct loopback_setup setup[MAX_PCM_SUBSTREAMS][2];
136         const char *timer_source;
137 };
138
139 struct loopback_pcm {
140         struct loopback *loopback;
141         struct snd_pcm_substream *substream;
142         struct loopback_cable *cable;
143         unsigned int pcm_buffer_size;
144         unsigned int buf_pos;   /* position in buffer */
145         unsigned int silent_size;
146         /* PCM parameters */
147         unsigned int pcm_period_size;
148         unsigned int pcm_bps;           /* bytes per second */
149         unsigned int pcm_salign;        /* bytes per sample * channels */
150         unsigned int pcm_rate_shift;    /* rate shift value */
151         /* flags */
152         unsigned int period_update_pending :1;
153         /* timer stuff */
154         unsigned int irq_pos;           /* fractional IRQ position in jiffies
155                                          * ticks
156                                          */
157         unsigned int period_size_frac;  /* period size in jiffies ticks */
158         unsigned int last_drift;
159         unsigned long last_jiffies;
160         /* If jiffies timer is used */
161         struct timer_list timer;
162 };
163
164 static struct platform_device *devices[SNDRV_CARDS];
165
166 static inline unsigned int byte_pos(struct loopback_pcm *dpcm, unsigned int x)
167 {
168         if (dpcm->pcm_rate_shift == NO_PITCH) {
169                 x /= HZ;
170         } else {
171                 x = div_u64(NO_PITCH * (unsigned long long)x,
172                             HZ * (unsigned long long)dpcm->pcm_rate_shift);
173         }
174         return x - (x % dpcm->pcm_salign);
175 }
176
177 static inline unsigned int frac_pos(struct loopback_pcm *dpcm, unsigned int x)
178 {
179         if (dpcm->pcm_rate_shift == NO_PITCH) { /* no pitch */
180                 return x * HZ;
181         } else {
182                 x = div_u64(dpcm->pcm_rate_shift * (unsigned long long)x * HZ,
183                             NO_PITCH);
184         }
185         return x;
186 }
187
188 static inline struct loopback_setup *get_setup(struct loopback_pcm *dpcm)
189 {
190         int device = dpcm->substream->pstr->pcm->device;
191         
192         if (dpcm->substream->stream == SNDRV_PCM_STREAM_PLAYBACK)
193                 device ^= 1;
194         return &dpcm->loopback->setup[dpcm->substream->number][device];
195 }
196
197 static inline unsigned int get_notify(struct loopback_pcm *dpcm)
198 {
199         return get_setup(dpcm)->notify;
200 }
201
202 static inline unsigned int get_rate_shift(struct loopback_pcm *dpcm)
203 {
204         return get_setup(dpcm)->rate_shift;
205 }
206
207 /* call in cable->lock */
208 static int loopback_jiffies_timer_start(struct loopback_pcm *dpcm)
209 {
210         unsigned long tick;
211         unsigned int rate_shift = get_rate_shift(dpcm);
212
213         if (rate_shift != dpcm->pcm_rate_shift) {
214                 dpcm->pcm_rate_shift = rate_shift;
215                 dpcm->period_size_frac = frac_pos(dpcm, dpcm->pcm_period_size);
216         }
217         if (dpcm->period_size_frac <= dpcm->irq_pos) {
218                 dpcm->irq_pos %= dpcm->period_size_frac;
219                 dpcm->period_update_pending = 1;
220         }
221         tick = dpcm->period_size_frac - dpcm->irq_pos;
222         tick = (tick + dpcm->pcm_bps - 1) / dpcm->pcm_bps;
223         mod_timer(&dpcm->timer, jiffies + tick);
224
225         return 0;
226 }
227
228 /* call in cable->lock */
229 static int loopback_snd_timer_start(struct loopback_pcm *dpcm)
230 {
231         struct loopback_cable *cable = dpcm->cable;
232         int err;
233
234         /* Loopback device has to use same period as timer card. Therefore
235          * wake up for each snd_pcm_period_elapsed() call of timer card.
236          */
237         err = snd_timer_start(cable->snd_timer.instance, 1);
238         if (err < 0) {
239                 /* do not report error if trying to start but already
240                  * running. For example called by opposite substream
241                  * of the same cable
242                  */
243                 if (err == -EBUSY)
244                         return 0;
245
246                 pcm_err(dpcm->substream->pcm,
247                         "snd_timer_start(%d,%d,%d) failed with %d",
248                         cable->snd_timer.id.card,
249                         cable->snd_timer.id.device,
250                         cable->snd_timer.id.subdevice,
251                         err);
252         }
253
254         return err;
255 }
256
257 /* call in cable->lock */
258 static inline int loopback_jiffies_timer_stop(struct loopback_pcm *dpcm)
259 {
260         del_timer(&dpcm->timer);
261         dpcm->timer.expires = 0;
262
263         return 0;
264 }
265
266 /* call in cable->lock */
267 static int loopback_snd_timer_stop(struct loopback_pcm *dpcm)
268 {
269         struct loopback_cable *cable = dpcm->cable;
270         int err;
271
272         /* only stop if both devices (playback and capture) are not running */
273         if (cable->running ^ cable->pause)
274                 return 0;
275
276         err = snd_timer_stop(cable->snd_timer.instance);
277         if (err < 0) {
278                 pcm_err(dpcm->substream->pcm,
279                         "snd_timer_stop(%d,%d,%d) failed with %d",
280                         cable->snd_timer.id.card,
281                         cable->snd_timer.id.device,
282                         cable->snd_timer.id.subdevice,
283                         err);
284         }
285
286         return err;
287 }
288
289 static inline int loopback_jiffies_timer_stop_sync(struct loopback_pcm *dpcm)
290 {
291         del_timer_sync(&dpcm->timer);
292
293         return 0;
294 }
295
296 /* call in loopback->cable_lock */
297 static int loopback_snd_timer_close_cable(struct loopback_pcm *dpcm)
298 {
299         struct loopback_cable *cable = dpcm->cable;
300
301         /* snd_timer was not opened */
302         if (!cable->snd_timer.instance)
303                 return 0;
304
305         /* wait till drain tasklet has finished if requested */
306         tasklet_kill(&cable->snd_timer.event_tasklet);
307
308         /* will only be called from free_cable() when other stream was
309          * already closed. Other stream cannot be reopened as long as
310          * loopback->cable_lock is locked. Therefore no need to lock
311          * cable->lock;
312          */
313         snd_timer_close(cable->snd_timer.instance);
314         snd_timer_instance_free(cable->snd_timer.instance);
315         memset(&cable->snd_timer, 0, sizeof(cable->snd_timer));
316
317         return 0;
318 }
319
320 static int loopback_check_format(struct loopback_cable *cable, int stream)
321 {
322         struct snd_pcm_runtime *runtime, *cruntime;
323         struct loopback_setup *setup;
324         struct snd_card *card;
325         int check;
326
327         if (cable->valid != CABLE_VALID_BOTH) {
328                 if (stream == SNDRV_PCM_STREAM_PLAYBACK)
329                         goto __notify;
330                 return 0;
331         }
332         runtime = cable->streams[SNDRV_PCM_STREAM_PLAYBACK]->
333                                                         substream->runtime;
334         cruntime = cable->streams[SNDRV_PCM_STREAM_CAPTURE]->
335                                                         substream->runtime;
336         check = runtime->format != cruntime->format ||
337                 runtime->rate != cruntime->rate ||
338                 runtime->channels != cruntime->channels;
339         if (!check)
340                 return 0;
341         if (stream == SNDRV_PCM_STREAM_CAPTURE) {
342                 return -EIO;
343         } else {
344                 snd_pcm_stop(cable->streams[SNDRV_PCM_STREAM_CAPTURE]->
345                                         substream, SNDRV_PCM_STATE_DRAINING);
346               __notify:
347                 runtime = cable->streams[SNDRV_PCM_STREAM_PLAYBACK]->
348                                                         substream->runtime;
349                 setup = get_setup(cable->streams[SNDRV_PCM_STREAM_PLAYBACK]);
350                 card = cable->streams[SNDRV_PCM_STREAM_PLAYBACK]->loopback->card;
351                 if (setup->format != runtime->format) {
352                         snd_ctl_notify(card, SNDRV_CTL_EVENT_MASK_VALUE,
353                                                         &setup->format_id);
354                         setup->format = runtime->format;
355                 }
356                 if (setup->rate != runtime->rate) {
357                         snd_ctl_notify(card, SNDRV_CTL_EVENT_MASK_VALUE,
358                                                         &setup->rate_id);
359                         setup->rate = runtime->rate;
360                 }
361                 if (setup->channels != runtime->channels) {
362                         snd_ctl_notify(card, SNDRV_CTL_EVENT_MASK_VALUE,
363                                                         &setup->channels_id);
364                         setup->channels = runtime->channels;
365                 }
366         }
367         return 0;
368 }
369
370 static void loopback_active_notify(struct loopback_pcm *dpcm)
371 {
372         snd_ctl_notify(dpcm->loopback->card,
373                        SNDRV_CTL_EVENT_MASK_VALUE,
374                        &get_setup(dpcm)->active_id);
375 }
376
377 static int loopback_trigger(struct snd_pcm_substream *substream, int cmd)
378 {
379         struct snd_pcm_runtime *runtime = substream->runtime;
380         struct loopback_pcm *dpcm = runtime->private_data;
381         struct loopback_cable *cable = dpcm->cable;
382         int err = 0, stream = 1 << substream->stream;
383
384         switch (cmd) {
385         case SNDRV_PCM_TRIGGER_START:
386                 err = loopback_check_format(cable, substream->stream);
387                 if (err < 0)
388                         return err;
389                 dpcm->last_jiffies = jiffies;
390                 dpcm->pcm_rate_shift = 0;
391                 dpcm->last_drift = 0;
392                 spin_lock(&cable->lock);        
393                 cable->running |= stream;
394                 cable->pause &= ~stream;
395                 err = cable->ops->start(dpcm);
396                 spin_unlock(&cable->lock);
397                 if (substream->stream == SNDRV_PCM_STREAM_PLAYBACK)
398                         loopback_active_notify(dpcm);
399                 break;
400         case SNDRV_PCM_TRIGGER_STOP:
401                 spin_lock(&cable->lock);        
402                 cable->running &= ~stream;
403                 cable->pause &= ~stream;
404                 err = cable->ops->stop(dpcm);
405                 spin_unlock(&cable->lock);
406                 if (substream->stream == SNDRV_PCM_STREAM_PLAYBACK)
407                         loopback_active_notify(dpcm);
408                 break;
409         case SNDRV_PCM_TRIGGER_PAUSE_PUSH:
410         case SNDRV_PCM_TRIGGER_SUSPEND:
411                 spin_lock(&cable->lock);        
412                 cable->pause |= stream;
413                 err = cable->ops->stop(dpcm);
414                 spin_unlock(&cable->lock);
415                 if (substream->stream == SNDRV_PCM_STREAM_PLAYBACK)
416                         loopback_active_notify(dpcm);
417                 break;
418         case SNDRV_PCM_TRIGGER_PAUSE_RELEASE:
419         case SNDRV_PCM_TRIGGER_RESUME:
420                 spin_lock(&cable->lock);
421                 dpcm->last_jiffies = jiffies;
422                 cable->pause &= ~stream;
423                 err = cable->ops->start(dpcm);
424                 spin_unlock(&cable->lock);
425                 if (substream->stream == SNDRV_PCM_STREAM_PLAYBACK)
426                         loopback_active_notify(dpcm);
427                 break;
428         default:
429                 return -EINVAL;
430         }
431         return err;
432 }
433
434 static void params_change(struct snd_pcm_substream *substream)
435 {
436         struct snd_pcm_runtime *runtime = substream->runtime;
437         struct loopback_pcm *dpcm = runtime->private_data;
438         struct loopback_cable *cable = dpcm->cable;
439
440         cable->hw.formats = pcm_format_to_bits(runtime->format);
441         cable->hw.rate_min = runtime->rate;
442         cable->hw.rate_max = runtime->rate;
443         cable->hw.channels_min = runtime->channels;
444         cable->hw.channels_max = runtime->channels;
445
446         if (cable->snd_timer.instance) {
447                 cable->hw.period_bytes_min =
448                                 frames_to_bytes(runtime, runtime->period_size);
449                 cable->hw.period_bytes_max = cable->hw.period_bytes_min;
450         }
451
452 }
453
454 static int loopback_prepare(struct snd_pcm_substream *substream)
455 {
456         struct snd_pcm_runtime *runtime = substream->runtime;
457         struct loopback_pcm *dpcm = runtime->private_data;
458         struct loopback_cable *cable = dpcm->cable;
459         int err, bps, salign;
460
461         if (cable->ops->stop_sync) {
462                 err = cable->ops->stop_sync(dpcm);
463                 if (err < 0)
464                         return err;
465         }
466
467         salign = (snd_pcm_format_physical_width(runtime->format) *
468                                                 runtime->channels) / 8;
469         bps = salign * runtime->rate;
470         if (bps <= 0 || salign <= 0)
471                 return -EINVAL;
472
473         dpcm->buf_pos = 0;
474         dpcm->pcm_buffer_size = frames_to_bytes(runtime, runtime->buffer_size);
475         if (substream->stream == SNDRV_PCM_STREAM_CAPTURE) {
476                 /* clear capture buffer */
477                 dpcm->silent_size = dpcm->pcm_buffer_size;
478                 snd_pcm_format_set_silence(runtime->format, runtime->dma_area,
479                                            runtime->buffer_size * runtime->channels);
480         }
481
482         dpcm->irq_pos = 0;
483         dpcm->period_update_pending = 0;
484         dpcm->pcm_bps = bps;
485         dpcm->pcm_salign = salign;
486         dpcm->pcm_period_size = frames_to_bytes(runtime, runtime->period_size);
487
488         mutex_lock(&dpcm->loopback->cable_lock);
489         if (!(cable->valid & ~(1 << substream->stream)) ||
490             (get_setup(dpcm)->notify &&
491              substream->stream == SNDRV_PCM_STREAM_PLAYBACK))
492                 params_change(substream);
493         cable->valid |= 1 << substream->stream;
494         mutex_unlock(&dpcm->loopback->cable_lock);
495
496         return 0;
497 }
498
499 static void clear_capture_buf(struct loopback_pcm *dpcm, unsigned int bytes)
500 {
501         struct snd_pcm_runtime *runtime = dpcm->substream->runtime;
502         char *dst = runtime->dma_area;
503         unsigned int dst_off = dpcm->buf_pos;
504
505         if (dpcm->silent_size >= dpcm->pcm_buffer_size)
506                 return;
507         if (dpcm->silent_size + bytes > dpcm->pcm_buffer_size)
508                 bytes = dpcm->pcm_buffer_size - dpcm->silent_size;
509
510         for (;;) {
511                 unsigned int size = bytes;
512                 if (dst_off + size > dpcm->pcm_buffer_size)
513                         size = dpcm->pcm_buffer_size - dst_off;
514                 snd_pcm_format_set_silence(runtime->format, dst + dst_off,
515                                            bytes_to_frames(runtime, size) *
516                                                 runtime->channels);
517                 dpcm->silent_size += size;
518                 bytes -= size;
519                 if (!bytes)
520                         break;
521                 dst_off = 0;
522         }
523 }
524
525 static void copy_play_buf(struct loopback_pcm *play,
526                           struct loopback_pcm *capt,
527                           unsigned int bytes)
528 {
529         struct snd_pcm_runtime *runtime = play->substream->runtime;
530         char *src = runtime->dma_area;
531         char *dst = capt->substream->runtime->dma_area;
532         unsigned int src_off = play->buf_pos;
533         unsigned int dst_off = capt->buf_pos;
534         unsigned int clear_bytes = 0;
535
536         /* check if playback is draining, trim the capture copy size
537          * when our pointer is at the end of playback ring buffer */
538         if (runtime->status->state == SNDRV_PCM_STATE_DRAINING &&
539             snd_pcm_playback_hw_avail(runtime) < runtime->buffer_size) { 
540                 snd_pcm_uframes_t appl_ptr, appl_ptr1, diff;
541                 appl_ptr = appl_ptr1 = runtime->control->appl_ptr;
542                 appl_ptr1 -= appl_ptr1 % runtime->buffer_size;
543                 appl_ptr1 += play->buf_pos / play->pcm_salign;
544                 if (appl_ptr < appl_ptr1)
545                         appl_ptr1 -= runtime->buffer_size;
546                 diff = (appl_ptr - appl_ptr1) * play->pcm_salign;
547                 if (diff < bytes) {
548                         clear_bytes = bytes - diff;
549                         bytes = diff;
550                 }
551         }
552
553         for (;;) {
554                 unsigned int size = bytes;
555                 if (src_off + size > play->pcm_buffer_size)
556                         size = play->pcm_buffer_size - src_off;
557                 if (dst_off + size > capt->pcm_buffer_size)
558                         size = capt->pcm_buffer_size - dst_off;
559                 memcpy(dst + dst_off, src + src_off, size);
560                 capt->silent_size = 0;
561                 bytes -= size;
562                 if (!bytes)
563                         break;
564                 src_off = (src_off + size) % play->pcm_buffer_size;
565                 dst_off = (dst_off + size) % capt->pcm_buffer_size;
566         }
567
568         if (clear_bytes > 0) {
569                 clear_capture_buf(capt, clear_bytes);
570                 capt->silent_size = 0;
571         }
572 }
573
574 static inline unsigned int bytepos_delta(struct loopback_pcm *dpcm,
575                                          unsigned int jiffies_delta)
576 {
577         unsigned long last_pos;
578         unsigned int delta;
579
580         last_pos = byte_pos(dpcm, dpcm->irq_pos);
581         dpcm->irq_pos += jiffies_delta * dpcm->pcm_bps;
582         delta = byte_pos(dpcm, dpcm->irq_pos) - last_pos;
583         if (delta >= dpcm->last_drift)
584                 delta -= dpcm->last_drift;
585         dpcm->last_drift = 0;
586         if (dpcm->irq_pos >= dpcm->period_size_frac) {
587                 dpcm->irq_pos %= dpcm->period_size_frac;
588                 dpcm->period_update_pending = 1;
589         }
590         return delta;
591 }
592
593 static inline void bytepos_finish(struct loopback_pcm *dpcm,
594                                   unsigned int delta)
595 {
596         dpcm->buf_pos += delta;
597         dpcm->buf_pos %= dpcm->pcm_buffer_size;
598 }
599
600 /* call in cable->lock */
601 static unsigned int loopback_jiffies_timer_pos_update
602                 (struct loopback_cable *cable)
603 {
604         struct loopback_pcm *dpcm_play =
605                         cable->streams[SNDRV_PCM_STREAM_PLAYBACK];
606         struct loopback_pcm *dpcm_capt =
607                         cable->streams[SNDRV_PCM_STREAM_CAPTURE];
608         unsigned long delta_play = 0, delta_capt = 0;
609         unsigned int running, count1, count2;
610
611         running = cable->running ^ cable->pause;
612         if (running & (1 << SNDRV_PCM_STREAM_PLAYBACK)) {
613                 delta_play = jiffies - dpcm_play->last_jiffies;
614                 dpcm_play->last_jiffies += delta_play;
615         }
616
617         if (running & (1 << SNDRV_PCM_STREAM_CAPTURE)) {
618                 delta_capt = jiffies - dpcm_capt->last_jiffies;
619                 dpcm_capt->last_jiffies += delta_capt;
620         }
621
622         if (delta_play == 0 && delta_capt == 0)
623                 goto unlock;
624                 
625         if (delta_play > delta_capt) {
626                 count1 = bytepos_delta(dpcm_play, delta_play - delta_capt);
627                 bytepos_finish(dpcm_play, count1);
628                 delta_play = delta_capt;
629         } else if (delta_play < delta_capt) {
630                 count1 = bytepos_delta(dpcm_capt, delta_capt - delta_play);
631                 clear_capture_buf(dpcm_capt, count1);
632                 bytepos_finish(dpcm_capt, count1);
633                 delta_capt = delta_play;
634         }
635
636         if (delta_play == 0 && delta_capt == 0)
637                 goto unlock;
638
639         /* note delta_capt == delta_play at this moment */
640         count1 = bytepos_delta(dpcm_play, delta_play);
641         count2 = bytepos_delta(dpcm_capt, delta_capt);
642         if (count1 < count2) {
643                 dpcm_capt->last_drift = count2 - count1;
644                 count1 = count2;
645         } else if (count1 > count2) {
646                 dpcm_play->last_drift = count1 - count2;
647         }
648         copy_play_buf(dpcm_play, dpcm_capt, count1);
649         bytepos_finish(dpcm_play, count1);
650         bytepos_finish(dpcm_capt, count1);
651  unlock:
652         return running;
653 }
654
655 static void loopback_jiffies_timer_function(struct timer_list *t)
656 {
657         struct loopback_pcm *dpcm = from_timer(dpcm, t, timer);
658         unsigned long flags;
659
660         spin_lock_irqsave(&dpcm->cable->lock, flags);
661         if (loopback_jiffies_timer_pos_update(dpcm->cable) &
662                         (1 << dpcm->substream->stream)) {
663                 loopback_jiffies_timer_start(dpcm);
664                 if (dpcm->period_update_pending) {
665                         dpcm->period_update_pending = 0;
666                         spin_unlock_irqrestore(&dpcm->cable->lock, flags);
667                         /* need to unlock before calling below */
668                         snd_pcm_period_elapsed(dpcm->substream);
669                         return;
670                 }
671         }
672         spin_unlock_irqrestore(&dpcm->cable->lock, flags);
673 }
674
675 /* call in cable->lock */
676 static int loopback_snd_timer_check_resolution(struct snd_pcm_runtime *runtime,
677                                                unsigned long resolution)
678 {
679         if (resolution != runtime->timer_resolution) {
680                 struct loopback_pcm *dpcm = runtime->private_data;
681                 struct loopback_cable *cable = dpcm->cable;
682                 /* Worst case estimation of possible values for resolution
683                  * resolution <= (512 * 1024) frames / 8kHz in nsec
684                  * resolution <= 65.536.000.000 nsec
685                  *
686                  * period_size <= 65.536.000.000 nsec / 1000nsec/usec * 192kHz +
687                  *  500.000
688                  * period_size <= 12.582.912.000.000  <64bit
689                  *  / 1.000.000 usec/sec
690                  */
691                 snd_pcm_uframes_t period_size_usec =
692                                 resolution / 1000 * runtime->rate;
693                 /* round to nearest sample rate */
694                 snd_pcm_uframes_t period_size =
695                                 (period_size_usec + 500 * 1000) / (1000 * 1000);
696
697                 pcm_err(dpcm->substream->pcm,
698                         "Period size (%lu frames) of loopback device is not corresponding to timer resolution (%lu nsec = %lu frames) of card timer %d,%d,%d. Use period size of %lu frames for loopback device.",
699                         runtime->period_size, resolution, period_size,
700                         cable->snd_timer.id.card,
701                         cable->snd_timer.id.device,
702                         cable->snd_timer.id.subdevice,
703                         period_size);
704                 return -EINVAL;
705         }
706         return 0;
707 }
708
709 static void loopback_snd_timer_period_elapsed(struct loopback_cable *cable,
710                                               int event,
711                                               unsigned long resolution)
712 {
713         struct loopback_pcm *dpcm_play, *dpcm_capt;
714         struct snd_pcm_substream *substream_play, *substream_capt;
715         struct snd_pcm_runtime *valid_runtime;
716         unsigned int running, elapsed_bytes;
717         unsigned long flags;
718
719         spin_lock_irqsave(&cable->lock, flags);
720         running = cable->running ^ cable->pause;
721         /* no need to do anything if no stream is running */
722         if (!running) {
723                 spin_unlock_irqrestore(&cable->lock, flags);
724                 return;
725         }
726
727         dpcm_play = cable->streams[SNDRV_PCM_STREAM_PLAYBACK];
728         dpcm_capt = cable->streams[SNDRV_PCM_STREAM_CAPTURE];
729         substream_play = (running & (1 << SNDRV_PCM_STREAM_PLAYBACK)) ?
730                         dpcm_play->substream : NULL;
731         substream_capt = (running & (1 << SNDRV_PCM_STREAM_CAPTURE)) ?
732                         dpcm_capt->substream : NULL;
733
734         if (event == SNDRV_TIMER_EVENT_MSTOP) {
735                 if (!dpcm_play ||
736                     dpcm_play->substream->runtime->status->state !=
737                                 SNDRV_PCM_STATE_DRAINING) {
738                         spin_unlock_irqrestore(&cable->lock, flags);
739                         return;
740                 }
741         }
742
743         valid_runtime = (running & (1 << SNDRV_PCM_STREAM_PLAYBACK)) ?
744                                 dpcm_play->substream->runtime :
745                                 dpcm_capt->substream->runtime;
746
747         /* resolution is only valid for SNDRV_TIMER_EVENT_TICK events */
748         if (event == SNDRV_TIMER_EVENT_TICK) {
749                 /* The hardware rules guarantee that playback and capture period
750                  * are the same. Therefore only one device has to be checked
751                  * here.
752                  */
753                 if (loopback_snd_timer_check_resolution(valid_runtime,
754                                                         resolution) < 0) {
755                         spin_unlock_irqrestore(&cable->lock, flags);
756                         if (substream_play)
757                                 snd_pcm_stop_xrun(substream_play);
758                         if (substream_capt)
759                                 snd_pcm_stop_xrun(substream_capt);
760                         return;
761                 }
762         }
763
764         elapsed_bytes = frames_to_bytes(valid_runtime,
765                                         valid_runtime->period_size);
766         /* The same timer interrupt is used for playback and capture device */
767         if ((running & (1 << SNDRV_PCM_STREAM_PLAYBACK)) &&
768             (running & (1 << SNDRV_PCM_STREAM_CAPTURE))) {
769                 copy_play_buf(dpcm_play, dpcm_capt, elapsed_bytes);
770                 bytepos_finish(dpcm_play, elapsed_bytes);
771                 bytepos_finish(dpcm_capt, elapsed_bytes);
772         } else if (running & (1 << SNDRV_PCM_STREAM_PLAYBACK)) {
773                 bytepos_finish(dpcm_play, elapsed_bytes);
774         } else if (running & (1 << SNDRV_PCM_STREAM_CAPTURE)) {
775                 clear_capture_buf(dpcm_capt, elapsed_bytes);
776                 bytepos_finish(dpcm_capt, elapsed_bytes);
777         }
778         spin_unlock_irqrestore(&cable->lock, flags);
779
780         if (substream_play)
781                 snd_pcm_period_elapsed(substream_play);
782         if (substream_capt)
783                 snd_pcm_period_elapsed(substream_capt);
784 }
785
786 static void loopback_snd_timer_function(struct snd_timer_instance *timeri,
787                                         unsigned long resolution,
788                                         unsigned long ticks)
789 {
790         struct loopback_cable *cable = timeri->callback_data;
791
792         loopback_snd_timer_period_elapsed(cable, SNDRV_TIMER_EVENT_TICK,
793                                           resolution);
794 }
795
796 static void loopback_snd_timer_tasklet(unsigned long arg)
797 {
798         struct snd_timer_instance *timeri = (struct snd_timer_instance *)arg;
799         struct loopback_cable *cable = timeri->callback_data;
800
801         loopback_snd_timer_period_elapsed(cable, SNDRV_TIMER_EVENT_MSTOP, 0);
802 }
803
804 static void loopback_snd_timer_event(struct snd_timer_instance *timeri,
805                                      int event,
806                                      struct timespec *tstamp,
807                                      unsigned long resolution)
808 {
809         /* Do not lock cable->lock here because timer->lock is already hold.
810          * There are other functions which first lock cable->lock and than
811          * timer->lock e.g.
812          * loopback_trigger()
813          * spin_lock(&cable->lock)
814          * loopback_snd_timer_start()
815          * snd_timer_start()
816          * spin_lock(&timer->lock)
817          * Therefore when using the oposit order of locks here it could result
818          * in a deadlock.
819          */
820
821         if (event == SNDRV_TIMER_EVENT_MSTOP) {
822                 struct loopback_cable *cable = timeri->callback_data;
823
824                 /* sound card of the timer was stopped. Therefore there will not
825                  * be any further timer callbacks. Due to this forward audio
826                  * data from here if in draining state. When still in running
827                  * state the streaming will be aborted by the usual timeout. It
828                  * should not be aborted here because may be the timer sound
829                  * card does only a recovery and the timer is back soon.
830                  * This tasklet triggers loopback_snd_timer_tasklet()
831                  */
832                 tasklet_schedule(&cable->snd_timer.event_tasklet);
833         }
834 }
835
836 static void loopback_jiffies_timer_dpcm_info(struct loopback_pcm *dpcm,
837                                              struct snd_info_buffer *buffer)
838 {
839         snd_iprintf(buffer, "    update_pending:\t%u\n",
840                     dpcm->period_update_pending);
841         snd_iprintf(buffer, "    irq_pos:\t\t%u\n", dpcm->irq_pos);
842         snd_iprintf(buffer, "    period_frac:\t%u\n", dpcm->period_size_frac);
843         snd_iprintf(buffer, "    last_jiffies:\t%lu (%lu)\n",
844                     dpcm->last_jiffies, jiffies);
845         snd_iprintf(buffer, "    timer_expires:\t%lu\n", dpcm->timer.expires);
846 }
847
848 static void loopback_snd_timer_dpcm_info(struct loopback_pcm *dpcm,
849                                          struct snd_info_buffer *buffer)
850 {
851         struct loopback_cable *cable = dpcm->cable;
852
853         snd_iprintf(buffer, "    sound timer:\thw:%d,%d,%d\n",
854                     cable->snd_timer.id.card,
855                     cable->snd_timer.id.device,
856                     cable->snd_timer.id.subdevice);
857         snd_iprintf(buffer, "    timer open:\t\t%s\n",
858                     (cable->snd_timer.stream == SNDRV_PCM_STREAM_CAPTURE) ?
859                             "capture" : "playback");
860 }
861
862 static snd_pcm_uframes_t loopback_pointer(struct snd_pcm_substream *substream)
863 {
864         struct snd_pcm_runtime *runtime = substream->runtime;
865         struct loopback_pcm *dpcm = runtime->private_data;
866         snd_pcm_uframes_t pos;
867
868         spin_lock(&dpcm->cable->lock);
869         if (dpcm->cable->ops->pos_update)
870                 dpcm->cable->ops->pos_update(dpcm->cable);
871         pos = dpcm->buf_pos;
872         spin_unlock(&dpcm->cable->lock);
873         return bytes_to_frames(runtime, pos);
874 }
875
876 static const struct snd_pcm_hardware loopback_pcm_hardware =
877 {
878         .info =         (SNDRV_PCM_INFO_INTERLEAVED | SNDRV_PCM_INFO_MMAP |
879                          SNDRV_PCM_INFO_MMAP_VALID | SNDRV_PCM_INFO_PAUSE |
880                          SNDRV_PCM_INFO_RESUME),
881         .formats =      (SNDRV_PCM_FMTBIT_S16_LE | SNDRV_PCM_FMTBIT_S16_BE |
882                          SNDRV_PCM_FMTBIT_S24_LE | SNDRV_PCM_FMTBIT_S24_BE |
883                          SNDRV_PCM_FMTBIT_S24_3LE | SNDRV_PCM_FMTBIT_S24_3BE |
884                          SNDRV_PCM_FMTBIT_S32_LE | SNDRV_PCM_FMTBIT_S32_BE |
885                          SNDRV_PCM_FMTBIT_FLOAT_LE | SNDRV_PCM_FMTBIT_FLOAT_BE),
886         .rates =        SNDRV_PCM_RATE_CONTINUOUS | SNDRV_PCM_RATE_8000_192000,
887         .rate_min =             8000,
888         .rate_max =             192000,
889         .channels_min =         1,
890         .channels_max =         32,
891         .buffer_bytes_max =     2 * 1024 * 1024,
892         .period_bytes_min =     64,
893         /* note check overflow in frac_pos() using pcm_rate_shift before
894            changing period_bytes_max value */
895         .period_bytes_max =     1024 * 1024,
896         .periods_min =          1,
897         .periods_max =          1024,
898         .fifo_size =            0,
899 };
900
901 static void loopback_runtime_free(struct snd_pcm_runtime *runtime)
902 {
903         struct loopback_pcm *dpcm = runtime->private_data;
904         kfree(dpcm);
905 }
906
907 static int loopback_hw_params(struct snd_pcm_substream *substream,
908                               struct snd_pcm_hw_params *params)
909 {
910         return snd_pcm_lib_malloc_pages(substream, params_buffer_bytes(params));
911 }
912
913 static int loopback_hw_free(struct snd_pcm_substream *substream)
914 {
915         struct snd_pcm_runtime *runtime = substream->runtime;
916         struct loopback_pcm *dpcm = runtime->private_data;
917         struct loopback_cable *cable = dpcm->cable;
918
919         mutex_lock(&dpcm->loopback->cable_lock);
920         cable->valid &= ~(1 << substream->stream);
921         mutex_unlock(&dpcm->loopback->cable_lock);
922         return snd_pcm_lib_free_pages(substream);
923 }
924
925 static unsigned int get_cable_index(struct snd_pcm_substream *substream)
926 {
927         if (!substream->pcm->device)
928                 return substream->stream;
929         else
930                 return !substream->stream;
931 }
932
933 static int rule_format(struct snd_pcm_hw_params *params,
934                        struct snd_pcm_hw_rule *rule)
935 {
936         struct loopback_pcm *dpcm = rule->private;
937         struct loopback_cable *cable = dpcm->cable;
938         struct snd_mask m;
939
940         snd_mask_none(&m);
941         mutex_lock(&dpcm->loopback->cable_lock);
942         m.bits[0] = (u_int32_t)cable->hw.formats;
943         m.bits[1] = (u_int32_t)(cable->hw.formats >> 32);
944         mutex_unlock(&dpcm->loopback->cable_lock);
945         return snd_mask_refine(hw_param_mask(params, rule->var), &m);
946 }
947
948 static int rule_rate(struct snd_pcm_hw_params *params,
949                      struct snd_pcm_hw_rule *rule)
950 {
951         struct loopback_pcm *dpcm = rule->private;
952         struct loopback_cable *cable = dpcm->cable;
953         struct snd_interval t;
954
955         mutex_lock(&dpcm->loopback->cable_lock);
956         t.min = cable->hw.rate_min;
957         t.max = cable->hw.rate_max;
958         mutex_unlock(&dpcm->loopback->cable_lock);
959         t.openmin = t.openmax = 0;
960         t.integer = 0;
961         return snd_interval_refine(hw_param_interval(params, rule->var), &t);
962 }
963
964 static int rule_channels(struct snd_pcm_hw_params *params,
965                          struct snd_pcm_hw_rule *rule)
966 {
967         struct loopback_pcm *dpcm = rule->private;
968         struct loopback_cable *cable = dpcm->cable;
969         struct snd_interval t;
970
971         mutex_lock(&dpcm->loopback->cable_lock);
972         t.min = cable->hw.channels_min;
973         t.max = cable->hw.channels_max;
974         mutex_unlock(&dpcm->loopback->cable_lock);
975         t.openmin = t.openmax = 0;
976         t.integer = 0;
977         return snd_interval_refine(hw_param_interval(params, rule->var), &t);
978 }
979
980 static int rule_period_bytes(struct snd_pcm_hw_params *params,
981                              struct snd_pcm_hw_rule *rule)
982 {
983         struct loopback_pcm *dpcm = rule->private;
984         struct loopback_cable *cable = dpcm->cable;
985         struct snd_interval t;
986
987         mutex_lock(&dpcm->loopback->cable_lock);
988         t.min = cable->hw.period_bytes_min;
989         t.max = cable->hw.period_bytes_max;
990         mutex_unlock(&dpcm->loopback->cable_lock);
991         t.openmin = 0;
992         t.openmax = 0;
993         t.integer = 0;
994         return snd_interval_refine(hw_param_interval(params, rule->var), &t);
995 }
996
997 static void free_cable(struct snd_pcm_substream *substream)
998 {
999         struct loopback *loopback = substream->private_data;
1000         int dev = get_cable_index(substream);
1001         struct loopback_cable *cable;
1002
1003         cable = loopback->cables[substream->number][dev];
1004         if (!cable)
1005                 return;
1006         if (cable->streams[!substream->stream]) {
1007                 /* other stream is still alive */
1008                 spin_lock_irq(&cable->lock);
1009                 cable->streams[substream->stream] = NULL;
1010                 spin_unlock_irq(&cable->lock);
1011         } else {
1012                 struct loopback_pcm *dpcm = substream->runtime->private_data;
1013
1014                 if (cable->ops && cable->ops->close_cable && dpcm)
1015                         cable->ops->close_cable(dpcm);
1016                 /* free the cable */
1017                 loopback->cables[substream->number][dev] = NULL;
1018                 kfree(cable);
1019         }
1020 }
1021
1022 static int loopback_jiffies_timer_open(struct loopback_pcm *dpcm)
1023 {
1024         timer_setup(&dpcm->timer, loopback_jiffies_timer_function, 0);
1025
1026         return 0;
1027 }
1028
1029 static struct loopback_ops loopback_jiffies_timer_ops = {
1030         .open = loopback_jiffies_timer_open,
1031         .start = loopback_jiffies_timer_start,
1032         .stop = loopback_jiffies_timer_stop,
1033         .stop_sync = loopback_jiffies_timer_stop_sync,
1034         .close_substream = loopback_jiffies_timer_stop_sync,
1035         .pos_update = loopback_jiffies_timer_pos_update,
1036         .dpcm_info = loopback_jiffies_timer_dpcm_info,
1037 };
1038
1039 static int loopback_parse_timer_id(const char *str,
1040                                    struct snd_timer_id *tid)
1041 {
1042         /* [<pref>:](<card name>|<card idx>)[{.,}<dev idx>[{.,}<subdev idx>]] */
1043         const char * const sep_dev = ".,";
1044         const char * const sep_pref = ":";
1045         const char *name = str;
1046         char *sep, save = '\0';
1047         int card_idx = 0, dev = 0, subdev = 0;
1048         int err;
1049
1050         sep = strpbrk(str, sep_pref);
1051         if (sep)
1052                 name = sep + 1;
1053         sep = strpbrk(name, sep_dev);
1054         if (sep) {
1055                 save = *sep;
1056                 *sep = '\0';
1057         }
1058         err = kstrtoint(name, 0, &card_idx);
1059         if (err == -EINVAL) {
1060                 /* Must be the name, not number */
1061                 for (card_idx = 0; card_idx < snd_ecards_limit; card_idx++) {
1062                         struct snd_card *card = snd_card_ref(card_idx);
1063
1064                         if (card) {
1065                                 if (!strcmp(card->id, name))
1066                                         err = 0;
1067                                 snd_card_unref(card);
1068                         }
1069                         if (!err)
1070                                 break;
1071                 }
1072         }
1073         if (sep) {
1074                 *sep = save;
1075                 if (!err) {
1076                         char *sep2, save2 = '\0';
1077
1078                         sep2 = strpbrk(sep + 1, sep_dev);
1079                         if (sep2) {
1080                                 save2 = *sep2;
1081                                 *sep2 = '\0';
1082                         }
1083                         err = kstrtoint(sep + 1, 0, &dev);
1084                         if (sep2) {
1085                                 *sep2 = save2;
1086                                 if (!err)
1087                                         err = kstrtoint(sep2 + 1, 0, &subdev);
1088                         }
1089                 }
1090         }
1091         if (!err && tid) {
1092                 tid->card = card_idx;
1093                 tid->device = dev;
1094                 tid->subdevice = subdev;
1095         }
1096         return err;
1097 }
1098
1099 /* call in loopback->cable_lock */
1100 static int loopback_snd_timer_open(struct loopback_pcm *dpcm)
1101 {
1102         int err = 0;
1103         struct snd_timer_id tid = {
1104                 .dev_class = SNDRV_TIMER_CLASS_PCM,
1105                 .dev_sclass = SNDRV_TIMER_SCLASS_APPLICATION,
1106         };
1107         struct snd_timer_instance *timeri;
1108         struct loopback_cable *cable = dpcm->cable;
1109
1110         /* check if timer was already opened. It is only opened once
1111          * per playback and capture subdevice (aka cable).
1112          */
1113         if (cable->snd_timer.instance)
1114                 goto exit;
1115
1116         err = loopback_parse_timer_id(dpcm->loopback->timer_source, &tid);
1117         if (err < 0) {
1118                 pcm_err(dpcm->substream->pcm,
1119                         "Parsing timer source \'%s\' failed with %d",
1120                         dpcm->loopback->timer_source, err);
1121                 goto exit;
1122         }
1123
1124         cable->snd_timer.stream = dpcm->substream->stream;
1125         cable->snd_timer.id = tid;
1126
1127         timeri = snd_timer_instance_new(dpcm->loopback->card->id);
1128         if (!timeri) {
1129                 err = -ENOMEM;
1130                 goto exit;
1131         }
1132         /* The callback has to be called from another tasklet. If
1133          * SNDRV_TIMER_IFLG_FAST is specified it will be called from the
1134          * snd_pcm_period_elapsed() call of the selected sound card.
1135          * snd_pcm_period_elapsed() helds snd_pcm_stream_lock_irqsave().
1136          * Due to our callback loopback_snd_timer_function() also calls
1137          * snd_pcm_period_elapsed() which calls snd_pcm_stream_lock_irqsave().
1138          * This would end up in a dead lock.
1139          */
1140         timeri->flags |= SNDRV_TIMER_IFLG_AUTO;
1141         timeri->callback = loopback_snd_timer_function;
1142         timeri->callback_data = (void *)cable;
1143         timeri->ccallback = loopback_snd_timer_event;
1144
1145         /* initialise a tasklet used for draining */
1146         tasklet_init(&cable->snd_timer.event_tasklet,
1147                      loopback_snd_timer_tasklet, (unsigned long)timeri);
1148
1149         /* The mutex loopback->cable_lock is kept locked.
1150          * Therefore snd_timer_open() cannot be called a second time
1151          * by the other device of the same cable.
1152          * Therefore the following issue cannot happen:
1153          * [proc1] Call loopback_timer_open() ->
1154          *         Unlock cable->lock for snd_timer_close/open() call
1155          * [proc2] Call loopback_timer_open() -> snd_timer_open(),
1156          *         snd_timer_start()
1157          * [proc1] Call snd_timer_open() and overwrite running timer
1158          *         instance
1159          */
1160         err = snd_timer_open(timeri, &cable->snd_timer.id, current->pid);
1161         if (err < 0) {
1162                 pcm_err(dpcm->substream->pcm,
1163                         "snd_timer_open (%d,%d,%d) failed with %d",
1164                         cable->snd_timer.id.card,
1165                         cable->snd_timer.id.device,
1166                         cable->snd_timer.id.subdevice,
1167                         err);
1168                 snd_timer_instance_free(timeri);
1169                 goto exit;
1170         }
1171
1172         cable->snd_timer.instance = timeri;
1173
1174 exit:
1175         return err;
1176 }
1177
1178 /* stop_sync() is not required for sound timer because it does not need to be
1179  * restarted in loopback_prepare() on Xrun recovery
1180  */
1181 static struct loopback_ops loopback_snd_timer_ops = {
1182         .open = loopback_snd_timer_open,
1183         .start = loopback_snd_timer_start,
1184         .stop = loopback_snd_timer_stop,
1185         .close_cable = loopback_snd_timer_close_cable,
1186         .dpcm_info = loopback_snd_timer_dpcm_info,
1187 };
1188
1189 static int loopback_open(struct snd_pcm_substream *substream)
1190 {
1191         struct snd_pcm_runtime *runtime = substream->runtime;
1192         struct loopback *loopback = substream->private_data;
1193         struct loopback_pcm *dpcm;
1194         struct loopback_cable *cable = NULL;
1195         int err = 0;
1196         int dev = get_cable_index(substream);
1197
1198         mutex_lock(&loopback->cable_lock);
1199         dpcm = kzalloc(sizeof(*dpcm), GFP_KERNEL);
1200         if (!dpcm) {
1201                 err = -ENOMEM;
1202                 goto unlock;
1203         }
1204         dpcm->loopback = loopback;
1205         dpcm->substream = substream;
1206
1207         cable = loopback->cables[substream->number][dev];
1208         if (!cable) {
1209                 cable = kzalloc(sizeof(*cable), GFP_KERNEL);
1210                 if (!cable) {
1211                         err = -ENOMEM;
1212                         goto unlock;
1213                 }
1214                 spin_lock_init(&cable->lock);
1215                 cable->hw = loopback_pcm_hardware;
1216                 if (loopback->timer_source)
1217                         cable->ops = &loopback_snd_timer_ops;
1218                 else
1219                         cable->ops = &loopback_jiffies_timer_ops;
1220                 loopback->cables[substream->number][dev] = cable;
1221         }
1222         dpcm->cable = cable;
1223         runtime->private_data = dpcm;
1224
1225         if (cable->ops->open) {
1226                 err = cable->ops->open(dpcm);
1227                 if (err < 0)
1228                         goto unlock;
1229         }
1230
1231         snd_pcm_hw_constraint_integer(runtime, SNDRV_PCM_HW_PARAM_PERIODS);
1232
1233         /* use dynamic rules based on actual runtime->hw values */
1234         /* note that the default rules created in the PCM midlevel code */
1235         /* are cached -> they do not reflect the actual state */
1236         err = snd_pcm_hw_rule_add(runtime, 0,
1237                                   SNDRV_PCM_HW_PARAM_FORMAT,
1238                                   rule_format, dpcm,
1239                                   SNDRV_PCM_HW_PARAM_FORMAT, -1);
1240         if (err < 0)
1241                 goto unlock;
1242         err = snd_pcm_hw_rule_add(runtime, 0,
1243                                   SNDRV_PCM_HW_PARAM_RATE,
1244                                   rule_rate, dpcm,
1245                                   SNDRV_PCM_HW_PARAM_RATE, -1);
1246         if (err < 0)
1247                 goto unlock;
1248         err = snd_pcm_hw_rule_add(runtime, 0,
1249                                   SNDRV_PCM_HW_PARAM_CHANNELS,
1250                                   rule_channels, dpcm,
1251                                   SNDRV_PCM_HW_PARAM_CHANNELS, -1);
1252         if (err < 0)
1253                 goto unlock;
1254
1255         /* In case of sound timer the period time of both devices of the same
1256          * loop has to be the same.
1257          * This rule only takes effect if a sound timer was chosen
1258          */
1259         if (cable->snd_timer.instance) {
1260                 err = snd_pcm_hw_rule_add(runtime, 0,
1261                                           SNDRV_PCM_HW_PARAM_PERIOD_BYTES,
1262                                           rule_period_bytes, dpcm,
1263                                           SNDRV_PCM_HW_PARAM_PERIOD_BYTES, -1);
1264                 if (err < 0)
1265                         goto unlock;
1266         }
1267
1268         /* loopback_runtime_free() has not to be called if kfree(dpcm) was
1269          * already called here. Otherwise it will end up with a double free.
1270          */
1271         runtime->private_free = loopback_runtime_free;
1272         if (get_notify(dpcm))
1273                 runtime->hw = loopback_pcm_hardware;
1274         else
1275                 runtime->hw = cable->hw;
1276
1277         spin_lock_irq(&cable->lock);
1278         cable->streams[substream->stream] = dpcm;
1279         spin_unlock_irq(&cable->lock);
1280
1281  unlock:
1282         if (err < 0) {
1283                 free_cable(substream);
1284                 kfree(dpcm);
1285         }
1286         mutex_unlock(&loopback->cable_lock);
1287         return err;
1288 }
1289
1290 static int loopback_close(struct snd_pcm_substream *substream)
1291 {
1292         struct loopback *loopback = substream->private_data;
1293         struct loopback_pcm *dpcm = substream->runtime->private_data;
1294         int err = 0;
1295
1296         if (dpcm->cable->ops->close_substream)
1297                 err = dpcm->cable->ops->close_substream(dpcm);
1298         mutex_lock(&loopback->cable_lock);
1299         free_cable(substream);
1300         mutex_unlock(&loopback->cable_lock);
1301         return err;
1302 }
1303
1304 static const struct snd_pcm_ops loopback_pcm_ops = {
1305         .open =         loopback_open,
1306         .close =        loopback_close,
1307         .ioctl =        snd_pcm_lib_ioctl,
1308         .hw_params =    loopback_hw_params,
1309         .hw_free =      loopback_hw_free,
1310         .prepare =      loopback_prepare,
1311         .trigger =      loopback_trigger,
1312         .pointer =      loopback_pointer,
1313 };
1314
1315 static int loopback_pcm_new(struct loopback *loopback,
1316                             int device, int substreams)
1317 {
1318         struct snd_pcm *pcm;
1319         int err;
1320
1321         err = snd_pcm_new(loopback->card, "Loopback PCM", device,
1322                           substreams, substreams, &pcm);
1323         if (err < 0)
1324                 return err;
1325         snd_pcm_set_ops(pcm, SNDRV_PCM_STREAM_PLAYBACK, &loopback_pcm_ops);
1326         snd_pcm_set_ops(pcm, SNDRV_PCM_STREAM_CAPTURE, &loopback_pcm_ops);
1327         snd_pcm_lib_preallocate_pages_for_all(pcm, SNDRV_DMA_TYPE_VMALLOC,
1328                                               NULL, 0, 0);
1329
1330         pcm->private_data = loopback;
1331         pcm->info_flags = 0;
1332         strcpy(pcm->name, "Loopback PCM");
1333
1334         loopback->pcm[device] = pcm;
1335         return 0;
1336 }
1337
1338 static int loopback_rate_shift_info(struct snd_kcontrol *kcontrol,   
1339                                     struct snd_ctl_elem_info *uinfo) 
1340 {
1341         uinfo->type = SNDRV_CTL_ELEM_TYPE_INTEGER;
1342         uinfo->count = 1;
1343         uinfo->value.integer.min = 80000;
1344         uinfo->value.integer.max = 120000;
1345         uinfo->value.integer.step = 1;
1346         return 0;
1347 }                                  
1348
1349 static int loopback_rate_shift_get(struct snd_kcontrol *kcontrol,
1350                                    struct snd_ctl_elem_value *ucontrol)
1351 {
1352         struct loopback *loopback = snd_kcontrol_chip(kcontrol);
1353         
1354         mutex_lock(&loopback->cable_lock);
1355         ucontrol->value.integer.value[0] =
1356                 loopback->setup[kcontrol->id.subdevice]
1357                                [kcontrol->id.device].rate_shift;
1358         mutex_unlock(&loopback->cable_lock);
1359         return 0;
1360 }
1361
1362 static int loopback_rate_shift_put(struct snd_kcontrol *kcontrol,
1363                                    struct snd_ctl_elem_value *ucontrol)
1364 {
1365         struct loopback *loopback = snd_kcontrol_chip(kcontrol);
1366         unsigned int val;
1367         int change = 0;
1368
1369         val = ucontrol->value.integer.value[0];
1370         if (val < 80000)
1371                 val = 80000;
1372         if (val > 120000)
1373                 val = 120000;   
1374         mutex_lock(&loopback->cable_lock);
1375         if (val != loopback->setup[kcontrol->id.subdevice]
1376                                   [kcontrol->id.device].rate_shift) {
1377                 loopback->setup[kcontrol->id.subdevice]
1378                                [kcontrol->id.device].rate_shift = val;
1379                 change = 1;
1380         }
1381         mutex_unlock(&loopback->cable_lock);
1382         return change;
1383 }
1384
1385 static int loopback_notify_get(struct snd_kcontrol *kcontrol,
1386                                struct snd_ctl_elem_value *ucontrol)
1387 {
1388         struct loopback *loopback = snd_kcontrol_chip(kcontrol);
1389         
1390         mutex_lock(&loopback->cable_lock);
1391         ucontrol->value.integer.value[0] =
1392                 loopback->setup[kcontrol->id.subdevice]
1393                                [kcontrol->id.device].notify;
1394         mutex_unlock(&loopback->cable_lock);
1395         return 0;
1396 }
1397
1398 static int loopback_notify_put(struct snd_kcontrol *kcontrol,
1399                                struct snd_ctl_elem_value *ucontrol)
1400 {
1401         struct loopback *loopback = snd_kcontrol_chip(kcontrol);
1402         unsigned int val;
1403         int change = 0;
1404
1405         val = ucontrol->value.integer.value[0] ? 1 : 0;
1406         mutex_lock(&loopback->cable_lock);
1407         if (val != loopback->setup[kcontrol->id.subdevice]
1408                                 [kcontrol->id.device].notify) {
1409                 loopback->setup[kcontrol->id.subdevice]
1410                         [kcontrol->id.device].notify = val;
1411                 change = 1;
1412         }
1413         mutex_unlock(&loopback->cable_lock);
1414         return change;
1415 }
1416
1417 static int loopback_active_get(struct snd_kcontrol *kcontrol,
1418                                struct snd_ctl_elem_value *ucontrol)
1419 {
1420         struct loopback *loopback = snd_kcontrol_chip(kcontrol);
1421         struct loopback_cable *cable;
1422
1423         unsigned int val = 0;
1424
1425         mutex_lock(&loopback->cable_lock);
1426         cable = loopback->cables[kcontrol->id.subdevice][kcontrol->id.device ^ 1];
1427         if (cable != NULL) {
1428                 unsigned int running = cable->running ^ cable->pause;
1429
1430                 val = (running & (1 << SNDRV_PCM_STREAM_PLAYBACK)) ? 1 : 0;
1431         }
1432         mutex_unlock(&loopback->cable_lock);
1433         ucontrol->value.integer.value[0] = val;
1434         return 0;
1435 }
1436
1437 static int loopback_format_info(struct snd_kcontrol *kcontrol,   
1438                                 struct snd_ctl_elem_info *uinfo) 
1439 {
1440         uinfo->type = SNDRV_CTL_ELEM_TYPE_INTEGER;
1441         uinfo->count = 1;
1442         uinfo->value.integer.min = 0;
1443         uinfo->value.integer.max = SNDRV_PCM_FORMAT_LAST;
1444         uinfo->value.integer.step = 1;
1445         return 0;
1446 }                                  
1447
1448 static int loopback_format_get(struct snd_kcontrol *kcontrol,
1449                                struct snd_ctl_elem_value *ucontrol)
1450 {
1451         struct loopback *loopback = snd_kcontrol_chip(kcontrol);
1452         
1453         ucontrol->value.integer.value[0] =
1454                 loopback->setup[kcontrol->id.subdevice]
1455                                [kcontrol->id.device].format;
1456         return 0;
1457 }
1458
1459 static int loopback_rate_info(struct snd_kcontrol *kcontrol,   
1460                               struct snd_ctl_elem_info *uinfo) 
1461 {
1462         uinfo->type = SNDRV_CTL_ELEM_TYPE_INTEGER;
1463         uinfo->count = 1;
1464         uinfo->value.integer.min = 0;
1465         uinfo->value.integer.max = 192000;
1466         uinfo->value.integer.step = 1;
1467         return 0;
1468 }                                  
1469
1470 static int loopback_rate_get(struct snd_kcontrol *kcontrol,
1471                              struct snd_ctl_elem_value *ucontrol)
1472 {
1473         struct loopback *loopback = snd_kcontrol_chip(kcontrol);
1474         
1475         mutex_lock(&loopback->cable_lock);
1476         ucontrol->value.integer.value[0] =
1477                 loopback->setup[kcontrol->id.subdevice]
1478                                [kcontrol->id.device].rate;
1479         mutex_unlock(&loopback->cable_lock);
1480         return 0;
1481 }
1482
1483 static int loopback_channels_info(struct snd_kcontrol *kcontrol,   
1484                                   struct snd_ctl_elem_info *uinfo) 
1485 {
1486         uinfo->type = SNDRV_CTL_ELEM_TYPE_INTEGER;
1487         uinfo->count = 1;
1488         uinfo->value.integer.min = 1;
1489         uinfo->value.integer.max = 1024;
1490         uinfo->value.integer.step = 1;
1491         return 0;
1492 }                                  
1493
1494 static int loopback_channels_get(struct snd_kcontrol *kcontrol,
1495                                  struct snd_ctl_elem_value *ucontrol)
1496 {
1497         struct loopback *loopback = snd_kcontrol_chip(kcontrol);
1498         
1499         mutex_lock(&loopback->cable_lock);
1500         ucontrol->value.integer.value[0] =
1501                 loopback->setup[kcontrol->id.subdevice]
1502                                [kcontrol->id.device].channels;
1503         mutex_unlock(&loopback->cable_lock);
1504         return 0;
1505 }
1506
1507 static struct snd_kcontrol_new loopback_controls[]  = {
1508 {
1509         .iface =        SNDRV_CTL_ELEM_IFACE_PCM,
1510         .name =         "PCM Rate Shift 100000",
1511         .info =         loopback_rate_shift_info,
1512         .get =          loopback_rate_shift_get,
1513         .put =          loopback_rate_shift_put,
1514 },
1515 {
1516         .iface =        SNDRV_CTL_ELEM_IFACE_PCM,
1517         .name =         "PCM Notify",
1518         .info =         snd_ctl_boolean_mono_info,
1519         .get =          loopback_notify_get,
1520         .put =          loopback_notify_put,
1521 },
1522 #define ACTIVE_IDX 2
1523 {
1524         .access =       SNDRV_CTL_ELEM_ACCESS_READ,
1525         .iface =        SNDRV_CTL_ELEM_IFACE_PCM,
1526         .name =         "PCM Slave Active",
1527         .info =         snd_ctl_boolean_mono_info,
1528         .get =          loopback_active_get,
1529 },
1530 #define FORMAT_IDX 3
1531 {
1532         .access =       SNDRV_CTL_ELEM_ACCESS_READ,
1533         .iface =        SNDRV_CTL_ELEM_IFACE_PCM,
1534         .name =         "PCM Slave Format",
1535         .info =         loopback_format_info,
1536         .get =          loopback_format_get
1537 },
1538 #define RATE_IDX 4
1539 {
1540         .access =       SNDRV_CTL_ELEM_ACCESS_READ,
1541         .iface =        SNDRV_CTL_ELEM_IFACE_PCM,
1542         .name =         "PCM Slave Rate",
1543         .info =         loopback_rate_info,
1544         .get =          loopback_rate_get
1545 },
1546 #define CHANNELS_IDX 5
1547 {
1548         .access =       SNDRV_CTL_ELEM_ACCESS_READ,
1549         .iface =        SNDRV_CTL_ELEM_IFACE_PCM,
1550         .name =         "PCM Slave Channels",
1551         .info =         loopback_channels_info,
1552         .get =          loopback_channels_get
1553 }
1554 };
1555
1556 static int loopback_mixer_new(struct loopback *loopback, int notify)
1557 {
1558         struct snd_card *card = loopback->card;
1559         struct snd_pcm *pcm;
1560         struct snd_kcontrol *kctl;
1561         struct loopback_setup *setup;
1562         int err, dev, substr, substr_count, idx;
1563
1564         strcpy(card->mixername, "Loopback Mixer");
1565         for (dev = 0; dev < 2; dev++) {
1566                 pcm = loopback->pcm[dev];
1567                 substr_count =
1568                     pcm->streams[SNDRV_PCM_STREAM_CAPTURE].substream_count;
1569                 for (substr = 0; substr < substr_count; substr++) {
1570                         setup = &loopback->setup[substr][dev];
1571                         setup->notify = notify;
1572                         setup->rate_shift = NO_PITCH;
1573                         setup->format = SNDRV_PCM_FORMAT_S16_LE;
1574                         setup->rate = 48000;
1575                         setup->channels = 2;
1576                         for (idx = 0; idx < ARRAY_SIZE(loopback_controls);
1577                                                                         idx++) {
1578                                 kctl = snd_ctl_new1(&loopback_controls[idx],
1579                                                     loopback);
1580                                 if (!kctl)
1581                                         return -ENOMEM;
1582                                 kctl->id.device = dev;
1583                                 kctl->id.subdevice = substr;
1584                                 switch (idx) {
1585                                 case ACTIVE_IDX:
1586                                         setup->active_id = kctl->id;
1587                                         break;
1588                                 case FORMAT_IDX:
1589                                         setup->format_id = kctl->id;
1590                                         break;
1591                                 case RATE_IDX:
1592                                         setup->rate_id = kctl->id;
1593                                         break;
1594                                 case CHANNELS_IDX:
1595                                         setup->channels_id = kctl->id;
1596                                         break;
1597                                 default:
1598                                         break;
1599                                 }
1600                                 err = snd_ctl_add(card, kctl);
1601                                 if (err < 0)
1602                                         return err;
1603                         }
1604                 }
1605         }
1606         return 0;
1607 }
1608
1609 static void print_dpcm_info(struct snd_info_buffer *buffer,
1610                             struct loopback_pcm *dpcm,
1611                             const char *id)
1612 {
1613         snd_iprintf(buffer, "  %s\n", id);
1614         if (dpcm == NULL) {
1615                 snd_iprintf(buffer, "    inactive\n");
1616                 return;
1617         }
1618         snd_iprintf(buffer, "    buffer_size:\t%u\n", dpcm->pcm_buffer_size);
1619         snd_iprintf(buffer, "    buffer_pos:\t\t%u\n", dpcm->buf_pos);
1620         snd_iprintf(buffer, "    silent_size:\t%u\n", dpcm->silent_size);
1621         snd_iprintf(buffer, "    period_size:\t%u\n", dpcm->pcm_period_size);
1622         snd_iprintf(buffer, "    bytes_per_sec:\t%u\n", dpcm->pcm_bps);
1623         snd_iprintf(buffer, "    sample_align:\t%u\n", dpcm->pcm_salign);
1624         snd_iprintf(buffer, "    rate_shift:\t\t%u\n", dpcm->pcm_rate_shift);
1625         if (dpcm->cable->ops->dpcm_info)
1626                 dpcm->cable->ops->dpcm_info(dpcm, buffer);
1627 }
1628
1629 static void print_substream_info(struct snd_info_buffer *buffer,
1630                                  struct loopback *loopback,
1631                                  int sub,
1632                                  int num)
1633 {
1634         struct loopback_cable *cable = loopback->cables[sub][num];
1635
1636         snd_iprintf(buffer, "Cable %i substream %i:\n", num, sub);
1637         if (cable == NULL) {
1638                 snd_iprintf(buffer, "  inactive\n");
1639                 return;
1640         }
1641         snd_iprintf(buffer, "  valid: %u\n", cable->valid);
1642         snd_iprintf(buffer, "  running: %u\n", cable->running);
1643         snd_iprintf(buffer, "  pause: %u\n", cable->pause);
1644         print_dpcm_info(buffer, cable->streams[0], "Playback");
1645         print_dpcm_info(buffer, cable->streams[1], "Capture");
1646 }
1647
1648 static void print_cable_info(struct snd_info_entry *entry,
1649                              struct snd_info_buffer *buffer)
1650 {
1651         struct loopback *loopback = entry->private_data;
1652         int sub, num;
1653
1654         mutex_lock(&loopback->cable_lock);
1655         num = entry->name[strlen(entry->name)-1];
1656         num = num == '0' ? 0 : 1;
1657         for (sub = 0; sub < MAX_PCM_SUBSTREAMS; sub++)
1658                 print_substream_info(buffer, loopback, sub, num);
1659         mutex_unlock(&loopback->cable_lock);
1660 }
1661
1662 static int loopback_cable_proc_new(struct loopback *loopback, int cidx)
1663 {
1664         char name[32];
1665
1666         snprintf(name, sizeof(name), "cable#%d", cidx);
1667         return snd_card_ro_proc_new(loopback->card, name, loopback,
1668                                     print_cable_info);
1669 }
1670
1671 static void loopback_set_timer_source(struct loopback *loopback,
1672                                       const char *value)
1673 {
1674         if (loopback->timer_source) {
1675                 devm_kfree(loopback->card->dev, loopback->timer_source);
1676                 loopback->timer_source = NULL;
1677         }
1678         if (value && *value)
1679                 loopback->timer_source = devm_kstrdup(loopback->card->dev,
1680                                                       value, GFP_KERNEL);
1681 }
1682
1683 static void print_timer_source_info(struct snd_info_entry *entry,
1684                                     struct snd_info_buffer *buffer)
1685 {
1686         struct loopback *loopback = entry->private_data;
1687
1688         mutex_lock(&loopback->cable_lock);
1689         snd_iprintf(buffer, "%s\n",
1690                     loopback->timer_source ? loopback->timer_source : "");
1691         mutex_unlock(&loopback->cable_lock);
1692 }
1693
1694 static void change_timer_source_info(struct snd_info_entry *entry,
1695                                      struct snd_info_buffer *buffer)
1696 {
1697         struct loopback *loopback = entry->private_data;
1698         char line[64];
1699
1700         mutex_lock(&loopback->cable_lock);
1701         if (!snd_info_get_line(buffer, line, sizeof(line)))
1702                 loopback_set_timer_source(loopback, strim(line));
1703         mutex_unlock(&loopback->cable_lock);
1704 }
1705
1706 static int loopback_timer_source_proc_new(struct loopback *loopback)
1707 {
1708         return snd_card_rw_proc_new(loopback->card, "timer_source", loopback,
1709                                     print_timer_source_info,
1710                                     change_timer_source_info);
1711 }
1712
1713 static int loopback_probe(struct platform_device *devptr)
1714 {
1715         struct snd_card *card;
1716         struct loopback *loopback;
1717         int dev = devptr->id;
1718         int err;
1719
1720         err = snd_card_new(&devptr->dev, index[dev], id[dev], THIS_MODULE,
1721                            sizeof(struct loopback), &card);
1722         if (err < 0)
1723                 return err;
1724         loopback = card->private_data;
1725
1726         if (pcm_substreams[dev] < 1)
1727                 pcm_substreams[dev] = 1;
1728         if (pcm_substreams[dev] > MAX_PCM_SUBSTREAMS)
1729                 pcm_substreams[dev] = MAX_PCM_SUBSTREAMS;
1730         
1731         loopback->card = card;
1732         loopback_set_timer_source(loopback, timer_source[dev]);
1733
1734         mutex_init(&loopback->cable_lock);
1735
1736         err = loopback_pcm_new(loopback, 0, pcm_substreams[dev]);
1737         if (err < 0)
1738                 goto __nodev;
1739         err = loopback_pcm_new(loopback, 1, pcm_substreams[dev]);
1740         if (err < 0)
1741                 goto __nodev;
1742         err = loopback_mixer_new(loopback, pcm_notify[dev] ? 1 : 0);
1743         if (err < 0)
1744                 goto __nodev;
1745         loopback_cable_proc_new(loopback, 0);
1746         loopback_cable_proc_new(loopback, 1);
1747         loopback_timer_source_proc_new(loopback);
1748         strcpy(card->driver, "Loopback");
1749         strcpy(card->shortname, "Loopback");
1750         sprintf(card->longname, "Loopback %i", dev + 1);
1751         err = snd_card_register(card);
1752         if (!err) {
1753                 platform_set_drvdata(devptr, card);
1754                 return 0;
1755         }
1756       __nodev:
1757         snd_card_free(card);
1758         return err;
1759 }
1760
1761 static int loopback_remove(struct platform_device *devptr)
1762 {
1763         snd_card_free(platform_get_drvdata(devptr));
1764         return 0;
1765 }
1766
1767 #ifdef CONFIG_PM_SLEEP
1768 static int loopback_suspend(struct device *pdev)
1769 {
1770         struct snd_card *card = dev_get_drvdata(pdev);
1771
1772         snd_power_change_state(card, SNDRV_CTL_POWER_D3hot);
1773         return 0;
1774 }
1775         
1776 static int loopback_resume(struct device *pdev)
1777 {
1778         struct snd_card *card = dev_get_drvdata(pdev);
1779
1780         snd_power_change_state(card, SNDRV_CTL_POWER_D0);
1781         return 0;
1782 }
1783
1784 static SIMPLE_DEV_PM_OPS(loopback_pm, loopback_suspend, loopback_resume);
1785 #define LOOPBACK_PM_OPS &loopback_pm
1786 #else
1787 #define LOOPBACK_PM_OPS NULL
1788 #endif
1789
1790 #define SND_LOOPBACK_DRIVER     "snd_aloop"
1791
1792 static struct platform_driver loopback_driver = {
1793         .probe          = loopback_probe,
1794         .remove         = loopback_remove,
1795         .driver         = {
1796                 .name   = SND_LOOPBACK_DRIVER,
1797                 .pm     = LOOPBACK_PM_OPS,
1798         },
1799 };
1800
1801 static void loopback_unregister_all(void)
1802 {
1803         int i;
1804
1805         for (i = 0; i < ARRAY_SIZE(devices); ++i)
1806                 platform_device_unregister(devices[i]);
1807         platform_driver_unregister(&loopback_driver);
1808 }
1809
1810 static int __init alsa_card_loopback_init(void)
1811 {
1812         int i, err, cards;
1813
1814         err = platform_driver_register(&loopback_driver);
1815         if (err < 0)
1816                 return err;
1817
1818
1819         cards = 0;
1820         for (i = 0; i < SNDRV_CARDS; i++) {
1821                 struct platform_device *device;
1822                 if (!enable[i])
1823                         continue;
1824                 device = platform_device_register_simple(SND_LOOPBACK_DRIVER,
1825                                                          i, NULL, 0);
1826                 if (IS_ERR(device))
1827                         continue;
1828                 if (!platform_get_drvdata(device)) {
1829                         platform_device_unregister(device);
1830                         continue;
1831                 }
1832                 devices[i] = device;
1833                 cards++;
1834         }
1835         if (!cards) {
1836 #ifdef MODULE
1837                 printk(KERN_ERR "aloop: No loopback enabled\n");
1838 #endif
1839                 loopback_unregister_all();
1840                 return -ENODEV;
1841         }
1842         return 0;
1843 }
1844
1845 static void __exit alsa_card_loopback_exit(void)
1846 {
1847         loopback_unregister_all();
1848 }
1849
1850 module_init(alsa_card_loopback_init)
1851 module_exit(alsa_card_loopback_exit)