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 İnan <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/module.h>
  38 #include <linux/platform_device.h>
  39 #include <sound/core.h>
  40 #include <sound/control.h>
  41 #include <sound/pcm.h>
  42 #include <sound/info.h>
  43 #include <sound/initval.h>
  44
  45 MODULE_AUTHOR("Jaroslav Kysela <perex@perex.cz>");
  46 MODULE_DESCRIPTION("A loopback soundcard");
  47 MODULE_LICENSE("GPL");
  48 MODULE_SUPPORTED_DEVICE("{{ALSA,Loopback soundcard}}");
  49
  50 #define MAX_PCM_SUBSTREAMS      8
  51
  52 static int index[SNDRV_CARDS] = SNDRV_DEFAULT_IDX;      /* Index 0-MAX */
  53 static char *id[SNDRV_CARDS] = SNDRV_DEFAULT_STR;       /* ID for this card */
  54 static bool enable[SNDRV_CARDS] = {1, [1 ... (SNDRV_CARDS - 1)] = 0};
  55 static int pcm_substreams[SNDRV_CARDS] = {[0 ... (SNDRV_CARDS - 1)] = 8};
  56 static int pcm_notify[SNDRV_CARDS];
  57
  58 module_param_array(index, int, NULL, 0444);
  59 MODULE_PARM_DESC(index, "Index value for loopback soundcard.");
  60 module_param_array(id, charp, NULL, 0444);
  61 MODULE_PARM_DESC(id, "ID string for loopback soundcard.");
  62 module_param_array(enable, bool, NULL, 0444);
  63 MODULE_PARM_DESC(enable, "Enable this loopback soundcard.");
  64 module_param_array(pcm_substreams, int, NULL, 0444);
  65 MODULE_PARM_DESC(pcm_substreams, "PCM substreams # (1-8) for loopback driver.");
  66 module_param_array(pcm_notify, int, NULL, 0444);
  67 MODULE_PARM_DESC(pcm_notify, "Break capture when PCM format/rate/channels changes.");
  68
  69 #define NO_PITCH 100000
  70
  71 struct loopback_pcm;
  72
  73 struct loopback_cable {
  74         spinlock_t lock;
  75         struct loopback_pcm *streams[2];
  76         struct snd_pcm_hardware hw;
  77         /* flags */
  78         unsigned int valid;
  79         unsigned int running;
  80         unsigned int pause;
  81 };
  82
  83 struct loopback_setup {
  84         unsigned int notify: 1;
  85         unsigned int rate_shift;
  86         unsigned int format;
  87         unsigned int rate;
  88         unsigned int channels;
  89         struct snd_ctl_elem_id active_id;
  90         struct snd_ctl_elem_id format_id;
  91         struct snd_ctl_elem_id rate_id;
  92         struct snd_ctl_elem_id channels_id;
  93 };
  94
  95 struct loopback {
  96         struct snd_card *card;
  97         struct mutex cable_lock;
  98         struct loopback_cable *cables[MAX_PCM_SUBSTREAMS][2];
  99         struct snd_pcm *pcm[2];
 100         struct loopback_setup setup[MAX_PCM_SUBSTREAMS][2];
 101 };
 102
 103 struct loopback_pcm {
 104         struct loopback *loopback;
 105         struct snd_pcm_substream *substream;
 106         struct loopback_cable *cable;
 107         unsigned int pcm_buffer_size;
 108         unsigned int buf_pos;   /* position in buffer */
 109         unsigned int silent_size;
 110         /* PCM parameters */
 111         unsigned int pcm_period_size;
 112         unsigned int pcm_bps;           /* bytes per second */
 113         unsigned int pcm_salign;        /* bytes per sample * channels */
 114         unsigned int pcm_rate_shift;    /* rate shift value */
 115         /* flags */
 116         unsigned int period_update_pending :1;
 117         /* timer stuff */
 118         unsigned int irq_pos;           /* fractional IRQ position */
 119         unsigned int period_size_frac;
 120         unsigned int last_drift;
 121         unsigned long last_jiffies;
 122         struct timer_list timer;
 123 };
 124
 125 static struct platform_device *devices[SNDRV_CARDS];
 126
 127 static inline unsigned int byte_pos(struct loopback_pcm *dpcm, unsigned int x)
 128 {
 129         if (dpcm->pcm_rate_shift == NO_PITCH) {
 130                 x /= HZ;
 131         } else {
 132                 x = div_u64(NO_PITCH * (unsigned long long)x,
 133                             HZ * (unsigned long long)dpcm->pcm_rate_shift);
 134         }
 135         return x - (x % dpcm->pcm_salign);
 136 }
 137
 138 static inline unsigned int frac_pos(struct loopback_pcm *dpcm, unsigned int x)
 139 {
 140         if (dpcm->pcm_rate_shift == NO_PITCH) { /* no pitch */
 141                 return x * HZ;
 142         } else {
 143                 x = div_u64(dpcm->pcm_rate_shift * (unsigned long long)x * HZ,
 144                             NO_PITCH);
 145         }
 146         return x;
 147 }
 148
 149 static inline struct loopback_setup *get_setup(struct loopback_pcm *dpcm)
 150 {
 151         int device = dpcm->substream->pstr->pcm->device;
 152
 153         if (dpcm->substream->stream == SNDRV_PCM_STREAM_PLAYBACK)
 154                 device ^= 1;
 155         return &dpcm->loopback->setup[dpcm->substream->number][device];
 156 }
 157
 158 static inline unsigned int get_notify(struct loopback_pcm *dpcm)
 159 {
 160         return get_setup(dpcm)->notify;
 161 }
 162
 163 static inline unsigned int get_rate_shift(struct loopback_pcm *dpcm)
 164 {
 165         return get_setup(dpcm)->rate_shift;
 166 }
 167
 168 static void loopback_timer_start(struct loopback_pcm *dpcm)
 169 {
 170         unsigned long tick;
 171         unsigned int rate_shift = get_rate_shift(dpcm);
 172
 173         if (rate_shift != dpcm->pcm_rate_shift) {
 174                 dpcm->pcm_rate_shift = rate_shift;
 175                 dpcm->period_size_frac = frac_pos(dpcm, dpcm->pcm_period_size);
 176         }
 177         if (dpcm->period_size_frac <= dpcm->irq_pos) {
 178                 dpcm->irq_pos %= dpcm->period_size_frac;
 179                 dpcm->period_update_pending = 1;
 180         }
 181         tick = dpcm->period_size_frac - dpcm->irq_pos;
 182         tick = (tick + dpcm->pcm_bps - 1) / dpcm->pcm_bps;
 183         dpcm->timer.expires = jiffies + tick;
 184         add_timer(&dpcm->timer);
 185 }
 186
 187 static inline void loopback_timer_stop(struct loopback_pcm *dpcm)
 188 {
 189         del_timer(&dpcm->timer);
 190         dpcm->timer.expires = 0;
 191 }
 192
 193 #define CABLE_VALID_PLAYBACK    (1 << SNDRV_PCM_STREAM_PLAYBACK)
 194 #define CABLE_VALID_CAPTURE     (1 << SNDRV_PCM_STREAM_CAPTURE)
 195 #define CABLE_VALID_BOTH        (CABLE_VALID_PLAYBACK|CABLE_VALID_CAPTURE)
 196
 197 static int loopback_check_format(struct loopback_cable *cable, int stream)
 198 {
 199         struct snd_pcm_runtime *runtime, *cruntime;
 200         struct loopback_setup *setup;
 201         struct snd_card *card;
 202         int check;
 203
 204         if (cable->valid != CABLE_VALID_BOTH) {
 205                 if (stream == SNDRV_PCM_STREAM_PLAYBACK)
 206                         goto __notify;
 207                 return 0;
 208         }
 209         runtime = cable->streams[SNDRV_PCM_STREAM_PLAYBACK]->
 210                                                         substream->runtime;
 211         cruntime = cable->streams[SNDRV_PCM_STREAM_CAPTURE]->
 212                                                         substream->runtime;
 213         check = runtime->format != cruntime->format ||
 214                 runtime->rate != cruntime->rate ||
 215                 runtime->channels != cruntime->channels;
 216         if (!check)
 217                 return 0;
 218         if (stream == SNDRV_PCM_STREAM_CAPTURE) {
 219                 return -EIO;
 220         } else {
 221                 snd_pcm_stop(cable->streams[SNDRV_PCM_STREAM_CAPTURE]->
 222                                         substream, SNDRV_PCM_STATE_DRAINING);
 223               __notify:
 224                 runtime = cable->streams[SNDRV_PCM_STREAM_PLAYBACK]->
 225                                                         substream->runtime;
 226                 setup = get_setup(cable->streams[SNDRV_PCM_STREAM_PLAYBACK]);
 227                 card = cable->streams[SNDRV_PCM_STREAM_PLAYBACK]->loopback->card;
 228                 if (setup->format != runtime->format) {
 229                         snd_ctl_notify(card, SNDRV_CTL_EVENT_MASK_VALUE,
 230                                                         &setup->format_id);
 231                         setup->format = runtime->format;
 232                 }
 233                 if (setup->rate != runtime->rate) {
 234                         snd_ctl_notify(card, SNDRV_CTL_EVENT_MASK_VALUE,
 235                                                         &setup->rate_id);
 236                         setup->rate = runtime->rate;
 237                 }
 238                 if (setup->channels != runtime->channels) {
 239                         snd_ctl_notify(card, SNDRV_CTL_EVENT_MASK_VALUE,
 240                                                         &setup->channels_id);
 241                         setup->channels = runtime->channels;
 242                 }
 243         }
 244         return 0;
 245 }
 246
 247 static void loopback_active_notify(struct loopback_pcm *dpcm)
 248 {
 249         snd_ctl_notify(dpcm->loopback->card,
 250                        SNDRV_CTL_EVENT_MASK_VALUE,
 251                        &get_setup(dpcm)->active_id);
 252 }
 253
 254 static int loopback_trigger(struct snd_pcm_substream *substream, int cmd)
 255 {
 256         struct snd_pcm_runtime *runtime = substream->runtime;
 257         struct loopback_pcm *dpcm = runtime->private_data;
 258         struct loopback_cable *cable = dpcm->cable;
 259         int err, stream = 1 << substream->stream;
 260
 261         switch (cmd) {
 262         case SNDRV_PCM_TRIGGER_START:
 263                 err = loopback_check_format(cable, substream->stream);
 264                 if (err < 0)
 265                         return err;
 266                 dpcm->last_jiffies = jiffies;
 267                 dpcm->pcm_rate_shift = 0;
 268                 dpcm->last_drift = 0;
 269                 spin_lock(&cable->lock);
 270                 cable->running |= stream;
 271                 cable->pause &= ~stream;
 272                 spin_unlock(&cable->lock);
 273                 loopback_timer_start(dpcm);
 274                 if (substream->stream == SNDRV_PCM_STREAM_PLAYBACK)
 275                         loopback_active_notify(dpcm);
 276                 break;
 277         case SNDRV_PCM_TRIGGER_STOP:
 278                 spin_lock(&cable->lock);
 279                 cable->running &= ~stream;
 280                 cable->pause &= ~stream;
 281                 spin_unlock(&cable->lock);
 282                 loopback_timer_stop(dpcm);
 283                 if (substream->stream == SNDRV_PCM_STREAM_PLAYBACK)
 284                         loopback_active_notify(dpcm);
 285                 break;
 286         case SNDRV_PCM_TRIGGER_PAUSE_PUSH:
 287                 spin_lock(&cable->lock);
 288                 cable->pause |= stream;
 289                 spin_unlock(&cable->lock);
 290                 loopback_timer_stop(dpcm);
 291                 break;
 292         case SNDRV_PCM_TRIGGER_PAUSE_RELEASE:
 293                 spin_lock(&cable->lock);
 294                 dpcm->last_jiffies = jiffies;
 295                 cable->pause &= ~stream;
 296                 spin_unlock(&cable->lock);
 297                 loopback_timer_start(dpcm);
 298                 break;
 299         default:
 300                 return -EINVAL;
 301         }
 302         return 0;
 303 }
 304
 305 static void params_change_substream(struct loopback_pcm *dpcm,
 306                                     struct snd_pcm_runtime *runtime)
 307 {
 308         struct snd_pcm_runtime *dst_runtime;
 309
 310         if (dpcm == NULL || dpcm->substream == NULL)
 311                 return;
 312         dst_runtime = dpcm->substream->runtime;
 313         if (dst_runtime == NULL)
 314                 return;
 315         dst_runtime->hw = dpcm->cable->hw;
 316 }
 317
 318 static void params_change(struct snd_pcm_substream *substream)
 319 {
 320         struct snd_pcm_runtime *runtime = substream->runtime;
 321         struct loopback_pcm *dpcm = runtime->private_data;
 322         struct loopback_cable *cable = dpcm->cable;
 323
 324         cable->hw.formats = (1ULL << runtime->format);
 325         cable->hw.rate_min = runtime->rate;
 326         cable->hw.rate_max = runtime->rate;
 327         cable->hw.channels_min = runtime->channels;
 328         cable->hw.channels_max = runtime->channels;
 329         params_change_substream(cable->streams[SNDRV_PCM_STREAM_PLAYBACK],
 330                                 runtime);
 331         params_change_substream(cable->streams[SNDRV_PCM_STREAM_CAPTURE],
 332                                 runtime);
 333 }
 334
 335 static int loopback_prepare(struct snd_pcm_substream *substream)
 336 {
 337         struct snd_pcm_runtime *runtime = substream->runtime;
 338         struct loopback_pcm *dpcm = runtime->private_data;
 339         struct loopback_cable *cable = dpcm->cable;
 340         int bps, salign;
 341
 342         salign = (snd_pcm_format_width(runtime->format) *
 343                                                 runtime->channels) / 8;
 344         bps = salign * runtime->rate;
 345         if (bps <= 0 || salign <= 0)
 346                 return -EINVAL;
 347
 348         dpcm->buf_pos = 0;
 349         dpcm->pcm_buffer_size = frames_to_bytes(runtime, runtime->buffer_size);
 350         if (substream->stream == SNDRV_PCM_STREAM_CAPTURE) {
 351                 /* clear capture buffer */
 352                 dpcm->silent_size = dpcm->pcm_buffer_size;
 353                 snd_pcm_format_set_silence(runtime->format, runtime->dma_area,
 354                                            runtime->buffer_size * runtime->channels);
 355         }
 356
 357         dpcm->irq_pos = 0;
 358         dpcm->period_update_pending = 0;
 359         dpcm->pcm_bps = bps;
 360         dpcm->pcm_salign = salign;
 361         dpcm->pcm_period_size = frames_to_bytes(runtime, runtime->period_size);
 362
 363         mutex_lock(&dpcm->loopback->cable_lock);
 364         if (!(cable->valid & ~(1 << substream->stream)) ||
 365             (get_setup(dpcm)->notify &&
 366              substream->stream == SNDRV_PCM_STREAM_PLAYBACK))
 367                 params_change(substream);
 368         cable->valid |= 1 << substream->stream;
 369         mutex_unlock(&dpcm->loopback->cable_lock);
 370
 371         return 0;
 372 }
 373
 374 static void clear_capture_buf(struct loopback_pcm *dpcm, unsigned int bytes)
 375 {
 376         struct snd_pcm_runtime *runtime = dpcm->substream->runtime;
 377         char *dst = runtime->dma_area;
 378         unsigned int dst_off = dpcm->buf_pos;
 379
 380         if (dpcm->silent_size >= dpcm->pcm_buffer_size)
 381                 return;
 382         if (dpcm->silent_size + bytes > dpcm->pcm_buffer_size)
 383                 bytes = dpcm->pcm_buffer_size - dpcm->silent_size;
 384
 385         for (;;) {
 386                 unsigned int size = bytes;
 387                 if (dst_off + size > dpcm->pcm_buffer_size)
 388                         size = dpcm->pcm_buffer_size - dst_off;
 389                 snd_pcm_format_set_silence(runtime->format, dst + dst_off,
 390                                            bytes_to_frames(runtime, size) *
 391                                                 runtime->channels);
 392                 dpcm->silent_size += size;
 393                 bytes -= size;
 394                 if (!bytes)
 395                         break;
 396                 dst_off = 0;
 397         }
 398 }
 399
 400 static void copy_play_buf(struct loopback_pcm *play,
 401                           struct loopback_pcm *capt,
 402                           unsigned int bytes)
 403 {
 404         struct snd_pcm_runtime *runtime = play->substream->runtime;
 405         char *src = runtime->dma_area;
 406         char *dst = capt->substream->runtime->dma_area;
 407         unsigned int src_off = play->buf_pos;
 408         unsigned int dst_off = capt->buf_pos;
 409         unsigned int clear_bytes = 0;
 410
 411         /* check if playback is draining, trim the capture copy size
 412          * when our pointer is at the end of playback ring buffer */
 413         if (runtime->status->state == SNDRV_PCM_STATE_DRAINING &&
 414             snd_pcm_playback_hw_avail(runtime) < runtime->buffer_size) {
 415                 snd_pcm_uframes_t appl_ptr, appl_ptr1, diff;
 416                 appl_ptr = appl_ptr1 = runtime->control->appl_ptr;
 417                 appl_ptr1 -= appl_ptr1 % runtime->buffer_size;
 418                 appl_ptr1 += play->buf_pos / play->pcm_salign;
 419                 if (appl_ptr < appl_ptr1)
 420                         appl_ptr1 -= runtime->buffer_size;
 421                 diff = (appl_ptr - appl_ptr1) * play->pcm_salign;
 422                 if (diff < bytes) {
 423                         clear_bytes = bytes - diff;
 424                         bytes = diff;
 425                 }
 426         }
 427
 428         for (;;) {
 429                 unsigned int size = bytes;
 430                 if (src_off + size > play->pcm_buffer_size)
 431                         size = play->pcm_buffer_size - src_off;
 432                 if (dst_off + size > capt->pcm_buffer_size)
 433                         size = capt->pcm_buffer_size - dst_off;
 434                 memcpy(dst + dst_off, src + src_off, size);
 435                 capt->silent_size = 0;
 436                 bytes -= size;
 437                 if (!bytes)
 438                         break;
 439                 src_off = (src_off + size) % play->pcm_buffer_size;
 440                 dst_off = (dst_off + size) % capt->pcm_buffer_size;
 441         }
 442
 443         if (clear_bytes > 0) {
 444                 clear_capture_buf(capt, clear_bytes);
 445                 capt->silent_size = 0;
 446         }
 447 }
 448
 449 static inline unsigned int bytepos_delta(struct loopback_pcm *dpcm,
 450                                          unsigned int jiffies_delta)
 451 {
 452         unsigned long last_pos;
 453         unsigned int delta;
 454
 455         last_pos = byte_pos(dpcm, dpcm->irq_pos);
 456         dpcm->irq_pos += jiffies_delta * dpcm->pcm_bps;
 457         delta = byte_pos(dpcm, dpcm->irq_pos) - last_pos;
 458         if (delta >= dpcm->last_drift)
 459                 delta -= dpcm->last_drift;
 460         dpcm->last_drift = 0;
 461         if (dpcm->irq_pos >= dpcm->period_size_frac) {
 462                 dpcm->irq_pos %= dpcm->period_size_frac;
 463                 dpcm->period_update_pending = 1;
 464         }
 465         return delta;
 466 }
 467
 468 static inline void bytepos_finish(struct loopback_pcm *dpcm,
 469                                   unsigned int delta)
 470 {
 471         dpcm->buf_pos += delta;
 472         dpcm->buf_pos %= dpcm->pcm_buffer_size;
 473 }
 474
 475 static unsigned int loopback_pos_update(struct loopback_cable *cable)
 476 {
 477         struct loopback_pcm *dpcm_play =
 478                         cable->streams[SNDRV_PCM_STREAM_PLAYBACK];
 479         struct loopback_pcm *dpcm_capt =
 480                         cable->streams[SNDRV_PCM_STREAM_CAPTURE];
 481         unsigned long delta_play = 0, delta_capt = 0;
 482         unsigned int running, count1, count2;
 483         unsigned long flags;
 484
 485         spin_lock_irqsave(&cable->lock, flags);
 486         running = cable->running ^ cable->pause;
 487         if (running & (1 << SNDRV_PCM_STREAM_PLAYBACK)) {
 488                 delta_play = jiffies - dpcm_play->last_jiffies;
 489                 dpcm_play->last_jiffies += delta_play;
 490         }
 491
 492         if (running & (1 << SNDRV_PCM_STREAM_CAPTURE)) {
 493                 delta_capt = jiffies - dpcm_capt->last_jiffies;
 494                 dpcm_capt->last_jiffies += delta_capt;
 495         }
 496
 497         if (delta_play == 0 && delta_capt == 0)
 498                 goto unlock;
 499
 500         if (delta_play > delta_capt) {
 501                 count1 = bytepos_delta(dpcm_play, delta_play - delta_capt);
 502                 bytepos_finish(dpcm_play, count1);
 503                 delta_play = delta_capt;
 504         } else if (delta_play < delta_capt) {
 505                 count1 = bytepos_delta(dpcm_capt, delta_capt - delta_play);
 506                 clear_capture_buf(dpcm_capt, count1);
 507                 bytepos_finish(dpcm_capt, count1);
 508                 delta_capt = delta_play;
 509         }
 510
 511         if (delta_play == 0 && delta_capt == 0)
 512                 goto unlock;
 513
 514         /* note delta_capt == delta_play at this moment */
 515         count1 = bytepos_delta(dpcm_play, delta_play);
 516         count2 = bytepos_delta(dpcm_capt, delta_capt);
 517         if (count1 < count2) {
 518                 dpcm_capt->last_drift = count2 - count1;
 519                 count1 = count2;
 520         } else if (count1 > count2) {
 521                 dpcm_play->last_drift = count1 - count2;
 522         }
 523         copy_play_buf(dpcm_play, dpcm_capt, count1);
 524         bytepos_finish(dpcm_play, count1);
 525         bytepos_finish(dpcm_capt, count1);
 526  unlock:
 527         spin_unlock_irqrestore(&cable->lock, flags);
 528         return running;
 529 }
 530
 531 static void loopback_timer_function(unsigned long data)
 532 {
 533         struct loopback_pcm *dpcm = (struct loopback_pcm *)data;
 534         unsigned int running;
 535
 536         running = loopback_pos_update(dpcm->cable);
 537         if (running & (1 << dpcm->substream->stream)) {
 538                 loopback_timer_start(dpcm);
 539                 if (dpcm->period_update_pending) {
 540                         dpcm->period_update_pending = 0;
 541                         snd_pcm_period_elapsed(dpcm->substream);
 542                 }
 543         }
 544 }
 545
 546 static snd_pcm_uframes_t loopback_pointer(struct snd_pcm_substream *substream)
 547 {
 548         struct snd_pcm_runtime *runtime = substream->runtime;
 549         struct loopback_pcm *dpcm = runtime->private_data;
 550
 551         loopback_pos_update(dpcm->cable);
 552         return bytes_to_frames(runtime, dpcm->buf_pos);
 553 }
 554
 555 static struct snd_pcm_hardware loopback_pcm_hardware =
 556 {
 557         .info =         (SNDRV_PCM_INFO_INTERLEAVED | SNDRV_PCM_INFO_MMAP |
 558                          SNDRV_PCM_INFO_MMAP_VALID | SNDRV_PCM_INFO_PAUSE),
 559         .formats =      (SNDRV_PCM_FMTBIT_S16_LE | SNDRV_PCM_FMTBIT_S16_BE |
 560                          SNDRV_PCM_FMTBIT_S32_LE | SNDRV_PCM_FMTBIT_S32_BE |
 561                          SNDRV_PCM_FMTBIT_FLOAT_LE | SNDRV_PCM_FMTBIT_FLOAT_BE),
 562         .rates =        SNDRV_PCM_RATE_CONTINUOUS | SNDRV_PCM_RATE_8000_192000,
 563         .rate_min =             8000,
 564         .rate_max =             192000,
 565         .channels_min =         1,
 566         .channels_max =         32,
 567         .buffer_bytes_max =     2 * 1024 * 1024,
 568         .period_bytes_min =     64,
 569         /* note check overflow in frac_pos() using pcm_rate_shift before
 570            changing period_bytes_max value */
 571         .period_bytes_max =     1024 * 1024,
 572         .periods_min =          1,
 573         .periods_max =          1024,
 574         .fifo_size =            0,
 575 };
 576
 577 static void loopback_runtime_free(struct snd_pcm_runtime *runtime)
 578 {
 579         struct loopback_pcm *dpcm = runtime->private_data;
 580         kfree(dpcm);
 581 }
 582
 583 static int loopback_hw_params(struct snd_pcm_substream *substream,
 584                               struct snd_pcm_hw_params *params)
 585 {
 586         return snd_pcm_lib_alloc_vmalloc_buffer(substream,
 587                                                 params_buffer_bytes(params));
 588 }
 589
 590 static int loopback_hw_free(struct snd_pcm_substream *substream)
 591 {
 592         struct snd_pcm_runtime *runtime = substream->runtime;
 593         struct loopback_pcm *dpcm = runtime->private_data;
 594         struct loopback_cable *cable = dpcm->cable;
 595
 596         mutex_lock(&dpcm->loopback->cable_lock);
 597         cable->valid &= ~(1 << substream->stream);
 598         mutex_unlock(&dpcm->loopback->cable_lock);
 599         return snd_pcm_lib_free_vmalloc_buffer(substream);
 600 }
 601
 602 static unsigned int get_cable_index(struct snd_pcm_substream *substream)
 603 {
 604         if (!substream->pcm->device)
 605                 return substream->stream;
 606         else
 607                 return !substream->stream;
 608 }
 609
 610 static int rule_format(struct snd_pcm_hw_params *params,
 611                        struct snd_pcm_hw_rule *rule)
 612 {
 613
 614         struct snd_pcm_hardware *hw = rule->private;
 615         struct snd_mask *maskp = hw_param_mask(params, rule->var);
 616
 617         maskp->bits[0] &= (u_int32_t)hw->formats;
 618         maskp->bits[1] &= (u_int32_t)(hw->formats >> 32);
 619         memset(maskp->bits + 2, 0, (SNDRV_MASK_MAX-64) / 8); /* clear rest */
 620         if (! maskp->bits[0] && ! maskp->bits[1])
 621                 return -EINVAL;
 622         return 0;
 623 }
 624
 625 static int rule_rate(struct snd_pcm_hw_params *params,
 626                      struct snd_pcm_hw_rule *rule)
 627 {
 628         struct snd_pcm_hardware *hw = rule->private;
 629         struct snd_interval t;
 630
 631         t.min = hw->rate_min;
 632         t.max = hw->rate_max;
 633         t.openmin = t.openmax = 0;
 634         t.integer = 0;
 635         return snd_interval_refine(hw_param_interval(params, rule->var), &t);
 636 }
 637
 638 static int rule_channels(struct snd_pcm_hw_params *params,
 639                          struct snd_pcm_hw_rule *rule)
 640 {
 641         struct snd_pcm_hardware *hw = rule->private;
 642         struct snd_interval t;
 643
 644         t.min = hw->channels_min;
 645         t.max = hw->channels_max;
 646         t.openmin = t.openmax = 0;
 647         t.integer = 0;
 648         return snd_interval_refine(hw_param_interval(params, rule->var), &t);
 649 }
 650
 651 static int loopback_open(struct snd_pcm_substream *substream)
 652 {
 653         struct snd_pcm_runtime *runtime = substream->runtime;
 654         struct loopback *loopback = substream->private_data;
 655         struct loopback_pcm *dpcm;
 656         struct loopback_cable *cable;
 657         int err = 0;
 658         int dev = get_cable_index(substream);
 659
 660         mutex_lock(&loopback->cable_lock);
 661         dpcm = kzalloc(sizeof(*dpcm), GFP_KERNEL);
 662         if (!dpcm) {
 663                 err = -ENOMEM;
 664                 goto unlock;
 665         }
 666         dpcm->loopback = loopback;
 667         dpcm->substream = substream;
 668         setup_timer(&dpcm->timer, loopback_timer_function,
 669                     (unsigned long)dpcm);
 670
 671         cable = loopback->cables[substream->number][dev];
 672         if (!cable) {
 673                 cable = kzalloc(sizeof(*cable), GFP_KERNEL);
 674                 if (!cable) {
 675                         kfree(dpcm);
 676                         err = -ENOMEM;
 677                         goto unlock;
 678                 }
 679                 spin_lock_init(&cable->lock);
 680                 cable->hw = loopback_pcm_hardware;
 681                 loopback->cables[substream->number][dev] = cable;
 682         }
 683         dpcm->cable = cable;
 684         cable->streams[substream->stream] = dpcm;
 685
 686         snd_pcm_hw_constraint_integer(runtime, SNDRV_PCM_HW_PARAM_PERIODS);
 687
 688         /* use dynamic rules based on actual runtime->hw values */
 689         /* note that the default rules created in the PCM midlevel code */
 690         /* are cached -> they do not reflect the actual state */
 691         err = snd_pcm_hw_rule_add(runtime, 0,
 692                                   SNDRV_PCM_HW_PARAM_FORMAT,
 693                                   rule_format, &runtime->hw,
 694                                   SNDRV_PCM_HW_PARAM_FORMAT, -1);
 695         if (err < 0)
 696                 goto unlock;
 697         err = snd_pcm_hw_rule_add(runtime, 0,
 698                                   SNDRV_PCM_HW_PARAM_RATE,
 699                                   rule_rate, &runtime->hw,
 700                                   SNDRV_PCM_HW_PARAM_RATE, -1);
 701         if (err < 0)
 702                 goto unlock;
 703         err = snd_pcm_hw_rule_add(runtime, 0,
 704                                   SNDRV_PCM_HW_PARAM_CHANNELS,
 705                                   rule_channels, &runtime->hw,
 706                                   SNDRV_PCM_HW_PARAM_CHANNELS, -1);
 707         if (err < 0)
 708                 goto unlock;
 709
 710         runtime->private_data = dpcm;
 711         runtime->private_free = loopback_runtime_free;
 712         if (get_notify(dpcm))
 713                 runtime->hw = loopback_pcm_hardware;
 714         else
 715                 runtime->hw = cable->hw;
 716  unlock:
 717         mutex_unlock(&loopback->cable_lock);
 718         return err;
 719 }
 720
 721 static int loopback_close(struct snd_pcm_substream *substream)
 722 {
 723         struct loopback *loopback = substream->private_data;
 724         struct loopback_pcm *dpcm = substream->runtime->private_data;
 725         struct loopback_cable *cable;
 726         int dev = get_cable_index(substream);
 727
 728         loopback_timer_stop(dpcm);
 729         mutex_lock(&loopback->cable_lock);
 730         cable = loopback->cables[substream->number][dev];
 731         if (cable->streams[!substream->stream]) {
 732                 /* other stream is still alive */
 733                 cable->streams[substream->stream] = NULL;
 734         } else {
 735                 /* free the cable */
 736                 loopback->cables[substream->number][dev] = NULL;
 737                 kfree(cable);
 738         }
 739         mutex_unlock(&loopback->cable_lock);
 740         return 0;
 741 }
 742
 743 static struct snd_pcm_ops loopback_playback_ops = {
 744         .open =         loopback_open,
 745         .close =        loopback_close,
 746         .ioctl =        snd_pcm_lib_ioctl,
 747         .hw_params =    loopback_hw_params,
 748         .hw_free =      loopback_hw_free,
 749         .prepare =      loopback_prepare,
 750         .trigger =      loopback_trigger,
 751         .pointer =      loopback_pointer,
 752         .page =         snd_pcm_lib_get_vmalloc_page,
 753         .mmap =         snd_pcm_lib_mmap_vmalloc,
 754 };
 755
 756 static struct snd_pcm_ops loopback_capture_ops = {
 757         .open =         loopback_open,
 758         .close =        loopback_close,
 759         .ioctl =        snd_pcm_lib_ioctl,
 760         .hw_params =    loopback_hw_params,
 761         .hw_free =      loopback_hw_free,
 762         .prepare =      loopback_prepare,
 763         .trigger =      loopback_trigger,
 764         .pointer =      loopback_pointer,
 765         .page =         snd_pcm_lib_get_vmalloc_page,
 766         .mmap =         snd_pcm_lib_mmap_vmalloc,
 767 };
 768
 769 static int __devinit loopback_pcm_new(struct loopback *loopback,
 770                                       int device, int substreams)
 771 {
 772         struct snd_pcm *pcm;
 773         int err;
 774
 775         err = snd_pcm_new(loopback->card, "Loopback PCM", device,
 776                           substreams, substreams, &pcm);
 777         if (err < 0)
 778                 return err;
 779         snd_pcm_set_ops(pcm, SNDRV_PCM_STREAM_PLAYBACK, &loopback_playback_ops);
 780         snd_pcm_set_ops(pcm, SNDRV_PCM_STREAM_CAPTURE, &loopback_capture_ops);
 781
 782         pcm->private_data = loopback;
 783         pcm->info_flags = 0;
 784         strcpy(pcm->name, "Loopback PCM");
 785
 786         loopback->pcm[device] = pcm;
 787         return 0;
 788 }
 789
 790 static int loopback_rate_shift_info(struct snd_kcontrol *kcontrol,
 791                                     struct snd_ctl_elem_info *uinfo)
 792 {
 793         uinfo->type = SNDRV_CTL_ELEM_TYPE_INTEGER;
 794         uinfo->count = 1;
 795         uinfo->value.integer.min = 80000;
 796         uinfo->value.integer.max = 120000;
 797         uinfo->value.integer.step = 1;
 798         return 0;
 799 }
 800
 801 static int loopback_rate_shift_get(struct snd_kcontrol *kcontrol,
 802                                    struct snd_ctl_elem_value *ucontrol)
 803 {
 804         struct loopback *loopback = snd_kcontrol_chip(kcontrol);
 805
 806         ucontrol->value.integer.value[0] =
 807                 loopback->setup[kcontrol->id.subdevice]
 808                                [kcontrol->id.device].rate_shift;
 809         return 0;
 810 }
 811
 812 static int loopback_rate_shift_put(struct snd_kcontrol *kcontrol,
 813                                    struct snd_ctl_elem_value *ucontrol)
 814 {
 815         struct loopback *loopback = snd_kcontrol_chip(kcontrol);
 816         unsigned int val;
 817         int change = 0;
 818
 819         val = ucontrol->value.integer.value[0];
 820         if (val < 80000)
 821                 val = 80000;
 822         if (val > 120000)
 823                 val = 120000;
 824         mutex_lock(&loopback->cable_lock);
 825         if (val != loopback->setup[kcontrol->id.subdevice]
 826                                   [kcontrol->id.device].rate_shift) {
 827                 loopback->setup[kcontrol->id.subdevice]
 828                                [kcontrol->id.device].rate_shift = val;
 829                 change = 1;
 830         }
 831         mutex_unlock(&loopback->cable_lock);
 832         return change;
 833 }
 834
 835 static int loopback_notify_get(struct snd_kcontrol *kcontrol,
 836                                struct snd_ctl_elem_value *ucontrol)
 837 {
 838         struct loopback *loopback = snd_kcontrol_chip(kcontrol);
 839
 840         ucontrol->value.integer.value[0] =
 841                 loopback->setup[kcontrol->id.subdevice]
 842                                [kcontrol->id.device].notify;
 843         return 0;
 844 }
 845
 846 static int loopback_notify_put(struct snd_kcontrol *kcontrol,
 847                                struct snd_ctl_elem_value *ucontrol)
 848 {
 849         struct loopback *loopback = snd_kcontrol_chip(kcontrol);
 850         unsigned int val;
 851         int change = 0;
 852
 853         val = ucontrol->value.integer.value[0] ? 1 : 0;
 854         if (val != loopback->setup[kcontrol->id.subdevice]
 855                                 [kcontrol->id.device].notify) {
 856                 loopback->setup[kcontrol->id.subdevice]
 857                         [kcontrol->id.device].notify = val;
 858                 change = 1;
 859         }
 860         return change;
 861 }
 862
 863 static int loopback_active_get(struct snd_kcontrol *kcontrol,
 864                                struct snd_ctl_elem_value *ucontrol)
 865 {
 866         struct loopback *loopback = snd_kcontrol_chip(kcontrol);
 867         struct loopback_cable *cable = loopback->cables
 868                         [kcontrol->id.subdevice][kcontrol->id.device ^ 1];
 869         unsigned int val = 0;
 870
 871         if (cable != NULL)
 872                 val = (cable->running & (1 << SNDRV_PCM_STREAM_PLAYBACK)) ?
 873                                                                         1 : 0;
 874         ucontrol->value.integer.value[0] = val;
 875         return 0;
 876 }
 877
 878 static int loopback_format_info(struct snd_kcontrol *kcontrol,
 879                                 struct snd_ctl_elem_info *uinfo)
 880 {
 881         uinfo->type = SNDRV_CTL_ELEM_TYPE_INTEGER;
 882         uinfo->count = 1;
 883         uinfo->value.integer.min = 0;
 884         uinfo->value.integer.max = SNDRV_PCM_FORMAT_LAST;
 885         uinfo->value.integer.step = 1;
 886         return 0;
 887 }
 888
 889 static int loopback_format_get(struct snd_kcontrol *kcontrol,
 890                                struct snd_ctl_elem_value *ucontrol)
 891 {
 892         struct loopback *loopback = snd_kcontrol_chip(kcontrol);
 893
 894         ucontrol->value.integer.value[0] =
 895                 loopback->setup[kcontrol->id.subdevice]
 896                                [kcontrol->id.device].format;
 897         return 0;
 898 }
 899
 900 static int loopback_rate_info(struct snd_kcontrol *kcontrol,
 901                               struct snd_ctl_elem_info *uinfo)
 902 {
 903         uinfo->type = SNDRV_CTL_ELEM_TYPE_INTEGER;
 904         uinfo->count = 1;
 905         uinfo->value.integer.min = 0;
 906         uinfo->value.integer.max = 192000;
 907         uinfo->value.integer.step = 1;
 908         return 0;
 909 }
 910
 911 static int loopback_rate_get(struct snd_kcontrol *kcontrol,
 912                              struct snd_ctl_elem_value *ucontrol)
 913 {
 914         struct loopback *loopback = snd_kcontrol_chip(kcontrol);
 915
 916         ucontrol->value.integer.value[0] =
 917                 loopback->setup[kcontrol->id.subdevice]
 918                                [kcontrol->id.device].rate;
 919         return 0;
 920 }
 921
 922 static int loopback_channels_info(struct snd_kcontrol *kcontrol,
 923                                   struct snd_ctl_elem_info *uinfo)
 924 {
 925         uinfo->type = SNDRV_CTL_ELEM_TYPE_INTEGER;
 926         uinfo->count = 1;
 927         uinfo->value.integer.min = 1;
 928         uinfo->value.integer.max = 1024;
 929         uinfo->value.integer.step = 1;
 930         return 0;
 931 }
 932
 933 static int loopback_channels_get(struct snd_kcontrol *kcontrol,
 934                                  struct snd_ctl_elem_value *ucontrol)
 935 {
 936         struct loopback *loopback = snd_kcontrol_chip(kcontrol);
 937
 938         ucontrol->value.integer.value[0] =
 939                 loopback->setup[kcontrol->id.subdevice]
 940                                [kcontrol->id.device].channels;
 941         return 0;
 942 }
 943
 944 static struct snd_kcontrol_new loopback_controls[]  __devinitdata = {
 945 {
 946         .iface =        SNDRV_CTL_ELEM_IFACE_PCM,
 947         .name =         "PCM Rate Shift 100000",
 948         .info =         loopback_rate_shift_info,
 949         .get =          loopback_rate_shift_get,
 950         .put =          loopback_rate_shift_put,
 951 },
 952 {
 953         .iface =        SNDRV_CTL_ELEM_IFACE_PCM,
 954         .name =         "PCM Notify",
 955         .info =         snd_ctl_boolean_mono_info,
 956         .get =          loopback_notify_get,
 957         .put =          loopback_notify_put,
 958 },
 959 #define ACTIVE_IDX 2
 960 {
 961         .access =       SNDRV_CTL_ELEM_ACCESS_READ,
 962         .iface =        SNDRV_CTL_ELEM_IFACE_PCM,
 963         .name =         "PCM Slave Active",
 964         .info =         snd_ctl_boolean_mono_info,
 965         .get =          loopback_active_get,
 966 },
 967 #define FORMAT_IDX 3
 968 {
 969         .access =       SNDRV_CTL_ELEM_ACCESS_READ,
 970         .iface =        SNDRV_CTL_ELEM_IFACE_PCM,
 971         .name =         "PCM Slave Format",
 972         .info =         loopback_format_info,
 973         .get =          loopback_format_get
 974 },
 975 #define RATE_IDX 4
 976 {
 977         .access =       SNDRV_CTL_ELEM_ACCESS_READ,
 978         .iface =        SNDRV_CTL_ELEM_IFACE_PCM,
 979         .name =         "PCM Slave Rate",
 980         .info =         loopback_rate_info,
 981         .get =          loopback_rate_get
 982 },
 983 #define CHANNELS_IDX 5
 984 {
 985         .access =       SNDRV_CTL_ELEM_ACCESS_READ,
 986         .iface =        SNDRV_CTL_ELEM_IFACE_PCM,
 987         .name =         "PCM Slave Channels",
 988         .info =         loopback_channels_info,
 989         .get =          loopback_channels_get
 990 }
 991 };
 992
 993 static int __devinit loopback_mixer_new(struct loopback *loopback, int notify)
 994 {
 995         struct snd_card *card = loopback->card;
 996         struct snd_pcm *pcm;
 997         struct snd_kcontrol *kctl;
 998         struct loopback_setup *setup;
 999         int err, dev, substr, substr_count, idx;
1000
1001         strcpy(card->mixername, "Loopback Mixer");
1002         for (dev = 0; dev < 2; dev++) {
1003                 pcm = loopback->pcm[dev];
1004                 substr_count =
1005                     pcm->streams[SNDRV_PCM_STREAM_CAPTURE].substream_count;
1006                 for (substr = 0; substr < substr_count; substr++) {
1007                         setup = &loopback->setup[substr][dev];
1008                         setup->notify = notify;
1009                         setup->rate_shift = NO_PITCH;
1010                         setup->format = SNDRV_PCM_FORMAT_S16_LE;
1011                         setup->rate = 48000;
1012                         setup->channels = 2;
1013                         for (idx = 0; idx < ARRAY_SIZE(loopback_controls);
1014                                                                         idx++) {
1015                                 kctl = snd_ctl_new1(&loopback_controls[idx],
1016                                                     loopback);
1017                                 if (!kctl)
1018                                         return -ENOMEM;
1019                                 kctl->id.device = dev;
1020                                 kctl->id.subdevice = substr;
1021                                 switch (idx) {
1022                                 case ACTIVE_IDX:
1023                                         setup->active_id = kctl->id;
1024                                         break;
1025                                 case FORMAT_IDX:
1026                                         setup->format_id = kctl->id;
1027                                         break;
1028                                 case RATE_IDX:
1029                                         setup->rate_id = kctl->id;
1030                                         break;
1031                                 case CHANNELS_IDX:
1032                                         setup->channels_id = kctl->id;
1033                                         break;
1034                                 default:
1035                                         break;
1036                                 }
1037                                 err = snd_ctl_add(card, kctl);
1038                                 if (err < 0)
1039                                         return err;
1040                         }
1041                 }
1042         }
1043         return 0;
1044 }
1045
1046 #ifdef CONFIG_PROC_FS
1047
1048 static void print_dpcm_info(struct snd_info_buffer *buffer,
1049                             struct loopback_pcm *dpcm,
1050                             const char *id)
1051 {
1052         snd_iprintf(buffer, "  %s\n", id);
1053         if (dpcm == NULL) {
1054                 snd_iprintf(buffer, "    inactive\n");
1055                 return;
1056         }
1057         snd_iprintf(buffer, "    buffer_size:\t%u\n", dpcm->pcm_buffer_size);
1058         snd_iprintf(buffer, "    buffer_pos:\t\t%u\n", dpcm->buf_pos);
1059         snd_iprintf(buffer, "    silent_size:\t%u\n", dpcm->silent_size);
1060         snd_iprintf(buffer, "    period_size:\t%u\n", dpcm->pcm_period_size);
1061         snd_iprintf(buffer, "    bytes_per_sec:\t%u\n", dpcm->pcm_bps);
1062         snd_iprintf(buffer, "    sample_align:\t%u\n", dpcm->pcm_salign);
1063         snd_iprintf(buffer, "    rate_shift:\t\t%u\n", dpcm->pcm_rate_shift);
1064         snd_iprintf(buffer, "    update_pending:\t%u\n",
1065                                                 dpcm->period_update_pending);
1066         snd_iprintf(buffer, "    irq_pos:\t\t%u\n", dpcm->irq_pos);
1067         snd_iprintf(buffer, "    period_frac:\t%u\n", dpcm->period_size_frac);
1068         snd_iprintf(buffer, "    last_jiffies:\t%lu (%lu)\n",
1069                                         dpcm->last_jiffies, jiffies);
1070         snd_iprintf(buffer, "    timer_expires:\t%lu\n", dpcm->timer.expires);
1071 }
1072
1073 static void print_substream_info(struct snd_info_buffer *buffer,
1074                                  struct loopback *loopback,
1075                                  int sub,
1076                                  int num)
1077 {
1078         struct loopback_cable *cable = loopback->cables[sub][num];
1079
1080         snd_iprintf(buffer, "Cable %i substream %i:\n", num, sub);
1081         if (cable == NULL) {
1082                 snd_iprintf(buffer, "  inactive\n");
1083                 return;
1084         }
1085         snd_iprintf(buffer, "  valid: %u\n", cable->valid);
1086         snd_iprintf(buffer, "  running: %u\n", cable->running);
1087         snd_iprintf(buffer, "  pause: %u\n", cable->pause);
1088         print_dpcm_info(buffer, cable->streams[0], "Playback");
1089         print_dpcm_info(buffer, cable->streams[1], "Capture");
1090 }
1091
1092 static void print_cable_info(struct snd_info_entry *entry,
1093                              struct snd_info_buffer *buffer)
1094 {
1095         struct loopback *loopback = entry->private_data;
1096         int sub, num;
1097
1098         mutex_lock(&loopback->cable_lock);
1099         num = entry->name[strlen(entry->name)-1];
1100         num = num == '0' ? 0 : 1;
1101         for (sub = 0; sub < MAX_PCM_SUBSTREAMS; sub++)
1102                 print_substream_info(buffer, loopback, sub, num);
1103         mutex_unlock(&loopback->cable_lock);
1104 }
1105
1106 static int __devinit loopback_proc_new(struct loopback *loopback, int cidx)
1107 {
1108         char name[32];
1109         struct snd_info_entry *entry;
1110         int err;
1111
1112         snprintf(name, sizeof(name), "cable#%d", cidx);
1113         err = snd_card_proc_new(loopback->card, name, &entry);
1114         if (err < 0)
1115                 return err;
1116
1117         snd_info_set_text_ops(entry, loopback, print_cable_info);
1118         return 0;
1119 }
1120
1121 #else /* !CONFIG_PROC_FS */
1122
1123 #define loopback_proc_new(loopback, cidx) do { } while (0)
1124
1125 #endif
1126
1127 static int __devinit loopback_probe(struct platform_device *devptr)
1128 {
1129         struct snd_card *card;
1130         struct loopback *loopback;
1131         int dev = devptr->id;
1132         int err;
1133
1134         err = snd_card_create(index[dev], id[dev], THIS_MODULE,
1135                               sizeof(struct loopback), &card);
1136         if (err < 0)
1137                 return err;
1138         loopback = card->private_data;
1139
1140         if (pcm_substreams[dev] < 1)
1141                 pcm_substreams[dev] = 1;
1142         if (pcm_substreams[dev] > MAX_PCM_SUBSTREAMS)
1143                 pcm_substreams[dev] = MAX_PCM_SUBSTREAMS;
1144
1145         loopback->card = card;
1146         mutex_init(&loopback->cable_lock);
1147
1148         err = loopback_pcm_new(loopback, 0, pcm_substreams[dev]);
1149         if (err < 0)
1150                 goto __nodev;
1151         err = loopback_pcm_new(loopback, 1, pcm_substreams[dev]);
1152         if (err < 0)
1153                 goto __nodev;
1154         err = loopback_mixer_new(loopback, pcm_notify[dev] ? 1 : 0);
1155         if (err < 0)
1156                 goto __nodev;
1157         loopback_proc_new(loopback, 0);
1158         loopback_proc_new(loopback, 1);
1159         strcpy(card->driver, "Loopback");
1160         strcpy(card->shortname, "Loopback");
1161         sprintf(card->longname, "Loopback %i", dev + 1);
1162         err = snd_card_register(card);
1163         if (!err) {
1164                 platform_set_drvdata(devptr, card);
1165                 return 0;
1166         }
1167       __nodev:
1168         snd_card_free(card);
1169         return err;
1170 }
1171
1172 static int __devexit loopback_remove(struct platform_device *devptr)
1173 {
1174         snd_card_free(platform_get_drvdata(devptr));
1175         platform_set_drvdata(devptr, NULL);
1176         return 0;
1177 }
1178
1179 #ifdef CONFIG_PM_SLEEP
1180 static int loopback_suspend(struct device *pdev)
1181 {
1182         struct snd_card *card = dev_get_drvdata(pdev);
1183         struct loopback *loopback = card->private_data;
1184
1185         snd_power_change_state(card, SNDRV_CTL_POWER_D3hot);
1186
1187         snd_pcm_suspend_all(loopback->pcm[0]);
1188         snd_pcm_suspend_all(loopback->pcm[1]);
1189         return 0;
1190 }
1191
1192 static int loopback_resume(struct device *pdev)
1193 {
1194         struct snd_card *card = dev_get_drvdata(pdev);
1195
1196         snd_power_change_state(card, SNDRV_CTL_POWER_D0);
1197         return 0;
1198 }
1199
1200 static SIMPLE_DEV_PM_OPS(loopback_pm, loopback_suspend, loopback_resume);
1201 #define LOOPBACK_PM_OPS &loopback_pm
1202 #else
1203 #define LOOPBACK_PM_OPS NULL
1204 #endif
1205
1206 #define SND_LOOPBACK_DRIVER     "snd_aloop"
1207
1208 static struct platform_driver loopback_driver = {
1209         .probe          = loopback_probe,
1210         .remove         = __devexit_p(loopback_remove),
1211         .driver         = {
1212                 .name   = SND_LOOPBACK_DRIVER,
1213                 .owner  = THIS_MODULE,
1214                 .pm     = LOOPBACK_PM_OPS,
1215         },
1216 };
1217
1218 static void loopback_unregister_all(void)
1219 {
1220         int i;
1221
1222         for (i = 0; i < ARRAY_SIZE(devices); ++i)
1223                 platform_device_unregister(devices[i]);
1224         platform_driver_unregister(&loopback_driver);
1225 }
1226
1227 static int __init alsa_card_loopback_init(void)
1228 {
1229         int i, err, cards;
1230
1231         err = platform_driver_register(&loopback_driver);
1232         if (err < 0)
1233                 return err;
1234
1235
1236         cards = 0;
1237         for (i = 0; i < SNDRV_CARDS; i++) {
1238                 struct platform_device *device;
1239                 if (!enable[i])
1240                         continue;
1241                 device = platform_device_register_simple(SND_LOOPBACK_DRIVER,
1242                                                          i, NULL, 0);
1243                 if (IS_ERR(device))
1244                         continue;
1245                 if (!platform_get_drvdata(device)) {
1246                         platform_device_unregister(device);
1247                         continue;
1248                 }
1249                 devices[i] = device;
1250                 cards++;
1251         }
1252         if (!cards) {
1253 #ifdef MODULE
1254                 printk(KERN_ERR "aloop: No loopback enabled\n");
1255 #endif
1256                 loopback_unregister_all();
1257                 return -ENODEV;
1258         }
1259         return 0;
1260 }
1261
1262 static void __exit alsa_card_loopback_exit(void)
1263 {
1264         loopback_unregister_all();
1265 }
1266
1267 module_init(alsa_card_loopback_init)
1268 module_exit(alsa_card_loopback_exit)