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