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         spinlock_t timer_lock;
 124 };
 125
 126 static struct platform_device *devices[SNDRV_CARDS];
 127
 128 static inline unsigned int byte_pos(struct loopback_pcm *dpcm, unsigned int x)
 129 {
 130         if (dpcm->pcm_rate_shift == NO_PITCH) {
 131                 x /= HZ;
 132         } else {
 133                 x = div_u64(NO_PITCH * (unsigned long long)x,
 134                             HZ * (unsigned long long)dpcm->pcm_rate_shift);
 135         }
 136         return x - (x % dpcm->pcm_salign);
 137 }
 138
 139 static inline unsigned int frac_pos(struct loopback_pcm *dpcm, unsigned int x)
 140 {
 141         if (dpcm->pcm_rate_shift == NO_PITCH) { /* no pitch */
 142                 return x * HZ;
 143         } else {
 144                 x = div_u64(dpcm->pcm_rate_shift * (unsigned long long)x * HZ,
 145                             NO_PITCH);
 146         }
 147         return x;
 148 }
 149
 150 static inline struct loopback_setup *get_setup(struct loopback_pcm *dpcm)
 151 {
 152         int device = dpcm->substream->pstr->pcm->device;
 153
 154         if (dpcm->substream->stream == SNDRV_PCM_STREAM_PLAYBACK)
 155                 device ^= 1;
 156         return &dpcm->loopback->setup[dpcm->substream->number][device];
 157 }
 158
 159 static inline unsigned int get_notify(struct loopback_pcm *dpcm)
 160 {
 161         return get_setup(dpcm)->notify;
 162 }
 163
 164 static inline unsigned int get_rate_shift(struct loopback_pcm *dpcm)
 165 {
 166         return get_setup(dpcm)->rate_shift;
 167 }
 168
 169 static void loopback_timer_start(struct loopback_pcm *dpcm)
 170 {
 171         unsigned long tick;
 172         unsigned int rate_shift = get_rate_shift(dpcm);
 173
 174         spin_lock(&dpcm->timer_lock);
 175         if (rate_shift != dpcm->pcm_rate_shift) {
 176                 dpcm->pcm_rate_shift = rate_shift;
 177                 dpcm->period_size_frac = frac_pos(dpcm, dpcm->pcm_period_size);
 178         }
 179         if (dpcm->period_size_frac <= dpcm->irq_pos) {
 180                 dpcm->irq_pos %= dpcm->period_size_frac;
 181                 dpcm->period_update_pending = 1;
 182         }
 183         tick = dpcm->period_size_frac - dpcm->irq_pos;
 184         tick = (tick + dpcm->pcm_bps - 1) / dpcm->pcm_bps;
 185         dpcm->timer.expires = jiffies + tick;
 186         add_timer(&dpcm->timer);
 187         spin_unlock(&dpcm->timer_lock);
 188 }
 189
 190 static inline void loopback_timer_stop(struct loopback_pcm *dpcm)
 191 {
 192         spin_lock(&dpcm->timer_lock);
 193         del_timer(&dpcm->timer);
 194         dpcm->timer.expires = 0;
 195         spin_unlock(&dpcm->timer_lock);
 196 }
 197
 198 #define CABLE_VALID_PLAYBACK    (1 << SNDRV_PCM_STREAM_PLAYBACK)
 199 #define CABLE_VALID_CAPTURE     (1 << SNDRV_PCM_STREAM_CAPTURE)
 200 #define CABLE_VALID_BOTH        (CABLE_VALID_PLAYBACK|CABLE_VALID_CAPTURE)
 201
 202 static int loopback_check_format(struct loopback_cable *cable, int stream)
 203 {
 204         struct snd_pcm_runtime *runtime, *cruntime;
 205         struct loopback_setup *setup;
 206         struct snd_card *card;
 207         int check;
 208
 209         if (cable->valid != CABLE_VALID_BOTH) {
 210                 if (stream == SNDRV_PCM_STREAM_PLAYBACK)
 211                         goto __notify;
 212                 return 0;
 213         }
 214         runtime = cable->streams[SNDRV_PCM_STREAM_PLAYBACK]->
 215                                                         substream->runtime;
 216         cruntime = cable->streams[SNDRV_PCM_STREAM_CAPTURE]->
 217                                                         substream->runtime;
 218         check = runtime->format != cruntime->format ||
 219                 runtime->rate != cruntime->rate ||
 220                 runtime->channels != cruntime->channels;
 221         if (!check)
 222                 return 0;
 223         if (stream == SNDRV_PCM_STREAM_CAPTURE) {
 224                 return -EIO;
 225         } else {
 226                 snd_pcm_stop(cable->streams[SNDRV_PCM_STREAM_CAPTURE]->
 227                                         substream, SNDRV_PCM_STATE_DRAINING);
 228               __notify:
 229                 runtime = cable->streams[SNDRV_PCM_STREAM_PLAYBACK]->
 230                                                         substream->runtime;
 231                 setup = get_setup(cable->streams[SNDRV_PCM_STREAM_PLAYBACK]);
 232                 card = cable->streams[SNDRV_PCM_STREAM_PLAYBACK]->loopback->card;
 233                 if (setup->format != runtime->format) {
 234                         snd_ctl_notify(card, SNDRV_CTL_EVENT_MASK_VALUE,
 235                                                         &setup->format_id);
 236                         setup->format = runtime->format;
 237                 }
 238                 if (setup->rate != runtime->rate) {
 239                         snd_ctl_notify(card, SNDRV_CTL_EVENT_MASK_VALUE,
 240                                                         &setup->rate_id);
 241                         setup->rate = runtime->rate;
 242                 }
 243                 if (setup->channels != runtime->channels) {
 244                         snd_ctl_notify(card, SNDRV_CTL_EVENT_MASK_VALUE,
 245                                                         &setup->channels_id);
 246                         setup->channels = runtime->channels;
 247                 }
 248         }
 249         return 0;
 250 }
 251
 252 static void loopback_active_notify(struct loopback_pcm *dpcm)
 253 {
 254         snd_ctl_notify(dpcm->loopback->card,
 255                        SNDRV_CTL_EVENT_MASK_VALUE,
 256                        &get_setup(dpcm)->active_id);
 257 }
 258
 259 static int loopback_trigger(struct snd_pcm_substream *substream, int cmd)
 260 {
 261         struct snd_pcm_runtime *runtime = substream->runtime;
 262         struct loopback_pcm *dpcm = runtime->private_data;
 263         struct loopback_cable *cable = dpcm->cable;
 264         int err, stream = 1 << substream->stream;
 265
 266         switch (cmd) {
 267         case SNDRV_PCM_TRIGGER_START:
 268                 err = loopback_check_format(cable, substream->stream);
 269                 if (err < 0)
 270                         return err;
 271                 dpcm->last_jiffies = jiffies;
 272                 dpcm->pcm_rate_shift = 0;
 273                 dpcm->last_drift = 0;
 274                 spin_lock(&cable->lock);
 275                 cable->running |= stream;
 276                 cable->pause &= ~stream;
 277                 spin_unlock(&cable->lock);
 278                 loopback_timer_start(dpcm);
 279                 if (substream->stream == SNDRV_PCM_STREAM_PLAYBACK)
 280                         loopback_active_notify(dpcm);
 281                 break;
 282         case SNDRV_PCM_TRIGGER_STOP:
 283                 spin_lock(&cable->lock);
 284                 cable->running &= ~stream;
 285                 cable->pause &= ~stream;
 286                 spin_unlock(&cable->lock);
 287                 loopback_timer_stop(dpcm);
 288                 if (substream->stream == SNDRV_PCM_STREAM_PLAYBACK)
 289                         loopback_active_notify(dpcm);
 290                 break;
 291         case SNDRV_PCM_TRIGGER_PAUSE_PUSH:
 292                 spin_lock(&cable->lock);
 293                 cable->pause |= stream;
 294                 spin_unlock(&cable->lock);
 295                 loopback_timer_stop(dpcm);
 296                 break;
 297         case SNDRV_PCM_TRIGGER_PAUSE_RELEASE:
 298                 spin_lock(&cable->lock);
 299                 dpcm->last_jiffies = jiffies;
 300                 cable->pause &= ~stream;
 301                 spin_unlock(&cable->lock);
 302                 loopback_timer_start(dpcm);
 303                 break;
 304         default:
 305                 return -EINVAL;
 306         }
 307         return 0;
 308 }
 309
 310 static void params_change_substream(struct loopback_pcm *dpcm,
 311                                     struct snd_pcm_runtime *runtime)
 312 {
 313         struct snd_pcm_runtime *dst_runtime;
 314
 315         if (dpcm == NULL || dpcm->substream == NULL)
 316                 return;
 317         dst_runtime = dpcm->substream->runtime;
 318         if (dst_runtime == NULL)
 319                 return;
 320         dst_runtime->hw = dpcm->cable->hw;
 321 }
 322
 323 static void params_change(struct snd_pcm_substream *substream)
 324 {
 325         struct snd_pcm_runtime *runtime = substream->runtime;
 326         struct loopback_pcm *dpcm = runtime->private_data;
 327         struct loopback_cable *cable = dpcm->cable;
 328
 329         cable->hw.formats = (1ULL << runtime->format);
 330         cable->hw.rate_min = runtime->rate;
 331         cable->hw.rate_max = runtime->rate;
 332         cable->hw.channels_min = runtime->channels;
 333         cable->hw.channels_max = runtime->channels;
 334         params_change_substream(cable->streams[SNDRV_PCM_STREAM_PLAYBACK],
 335                                 runtime);
 336         params_change_substream(cable->streams[SNDRV_PCM_STREAM_CAPTURE],
 337                                 runtime);
 338 }
 339
 340 static int loopback_prepare(struct snd_pcm_substream *substream)
 341 {
 342         struct snd_pcm_runtime *runtime = substream->runtime;
 343         struct loopback_pcm *dpcm = runtime->private_data;
 344         struct loopback_cable *cable = dpcm->cable;
 345         int bps, salign;
 346
 347         salign = (snd_pcm_format_width(runtime->format) *
 348                                                 runtime->channels) / 8;
 349         bps = salign * runtime->rate;
 350         if (bps <= 0 || salign <= 0)
 351                 return -EINVAL;
 352
 353         dpcm->buf_pos = 0;
 354         dpcm->pcm_buffer_size = frames_to_bytes(runtime, runtime->buffer_size);
 355         if (substream->stream == SNDRV_PCM_STREAM_CAPTURE) {
 356                 /* clear capture buffer */
 357                 dpcm->silent_size = dpcm->pcm_buffer_size;
 358                 snd_pcm_format_set_silence(runtime->format, runtime->dma_area,
 359                                            runtime->buffer_size * runtime->channels);
 360         }
 361
 362         dpcm->irq_pos = 0;
 363         dpcm->period_update_pending = 0;
 364         dpcm->pcm_bps = bps;
 365         dpcm->pcm_salign = salign;
 366         dpcm->pcm_period_size = frames_to_bytes(runtime, runtime->period_size);
 367
 368         mutex_lock(&dpcm->loopback->cable_lock);
 369         if (!(cable->valid & ~(1 << substream->stream)) ||
 370             (get_setup(dpcm)->notify &&
 371              substream->stream == SNDRV_PCM_STREAM_PLAYBACK))
 372                 params_change(substream);
 373         cable->valid |= 1 << substream->stream;
 374         mutex_unlock(&dpcm->loopback->cable_lock);
 375
 376         return 0;
 377 }
 378
 379 static void clear_capture_buf(struct loopback_pcm *dpcm, unsigned int bytes)
 380 {
 381         struct snd_pcm_runtime *runtime = dpcm->substream->runtime;
 382         char *dst = runtime->dma_area;
 383         unsigned int dst_off = dpcm->buf_pos;
 384
 385         if (dpcm->silent_size >= dpcm->pcm_buffer_size)
 386                 return;
 387         if (dpcm->silent_size + bytes > dpcm->pcm_buffer_size)
 388                 bytes = dpcm->pcm_buffer_size - dpcm->silent_size;
 389
 390         for (;;) {
 391                 unsigned int size = bytes;
 392                 if (dst_off + size > dpcm->pcm_buffer_size)
 393                         size = dpcm->pcm_buffer_size - dst_off;
 394                 snd_pcm_format_set_silence(runtime->format, dst + dst_off,
 395                                            bytes_to_frames(runtime, size) *
 396                                                 runtime->channels);
 397                 dpcm->silent_size += size;
 398                 bytes -= size;
 399                 if (!bytes)
 400                         break;
 401                 dst_off = 0;
 402         }
 403 }
 404
 405 static void copy_play_buf(struct loopback_pcm *play,
 406                           struct loopback_pcm *capt,
 407                           unsigned int bytes)
 408 {
 409         struct snd_pcm_runtime *runtime = play->substream->runtime;
 410         char *src = runtime->dma_area;
 411         char *dst = capt->substream->runtime->dma_area;
 412         unsigned int src_off = play->buf_pos;
 413         unsigned int dst_off = capt->buf_pos;
 414         unsigned int clear_bytes = 0;
 415
 416         /* check if playback is draining, trim the capture copy size
 417          * when our pointer is at the end of playback ring buffer */
 418         if (runtime->status->state == SNDRV_PCM_STATE_DRAINING &&
 419             snd_pcm_playback_hw_avail(runtime) < runtime->buffer_size) {
 420                 snd_pcm_uframes_t appl_ptr, appl_ptr1, diff;
 421                 appl_ptr = appl_ptr1 = runtime->control->appl_ptr;
 422                 appl_ptr1 -= appl_ptr1 % runtime->buffer_size;
 423                 appl_ptr1 += play->buf_pos / play->pcm_salign;
 424                 if (appl_ptr < appl_ptr1)
 425                         appl_ptr1 -= runtime->buffer_size;
 426                 diff = (appl_ptr - appl_ptr1) * play->pcm_salign;
 427                 if (diff < bytes) {
 428                         clear_bytes = bytes - diff;
 429                         bytes = diff;
 430                 }
 431         }
 432
 433         for (;;) {
 434                 unsigned int size = bytes;
 435                 if (src_off + size > play->pcm_buffer_size)
 436                         size = play->pcm_buffer_size - src_off;
 437                 if (dst_off + size > capt->pcm_buffer_size)
 438                         size = capt->pcm_buffer_size - dst_off;
 439                 memcpy(dst + dst_off, src + src_off, size);
 440                 capt->silent_size = 0;
 441                 bytes -= size;
 442                 if (!bytes)
 443                         break;
 444                 src_off = (src_off + size) % play->pcm_buffer_size;
 445                 dst_off = (dst_off + size) % capt->pcm_buffer_size;
 446         }
 447
 448         if (clear_bytes > 0) {
 449                 clear_capture_buf(capt, clear_bytes);
 450                 capt->silent_size = 0;
 451         }
 452 }
 453
 454 static inline unsigned int bytepos_delta(struct loopback_pcm *dpcm,
 455                                          unsigned int jiffies_delta)
 456 {
 457         unsigned long last_pos;
 458         unsigned int delta;
 459
 460         last_pos = byte_pos(dpcm, dpcm->irq_pos);
 461         dpcm->irq_pos += jiffies_delta * dpcm->pcm_bps;
 462         delta = byte_pos(dpcm, dpcm->irq_pos) - last_pos;
 463         if (delta >= dpcm->last_drift)
 464                 delta -= dpcm->last_drift;
 465         dpcm->last_drift = 0;
 466         if (dpcm->irq_pos >= dpcm->period_size_frac) {
 467                 dpcm->irq_pos %= dpcm->period_size_frac;
 468                 dpcm->period_update_pending = 1;
 469         }
 470         return delta;
 471 }
 472
 473 static inline void bytepos_finish(struct loopback_pcm *dpcm,
 474                                   unsigned int delta)
 475 {
 476         dpcm->buf_pos += delta;
 477         dpcm->buf_pos %= dpcm->pcm_buffer_size;
 478 }
 479
 480 static unsigned int loopback_pos_update(struct loopback_cable *cable)
 481 {
 482         struct loopback_pcm *dpcm_play =
 483                         cable->streams[SNDRV_PCM_STREAM_PLAYBACK];
 484         struct loopback_pcm *dpcm_capt =
 485                         cable->streams[SNDRV_PCM_STREAM_CAPTURE];
 486         unsigned long delta_play = 0, delta_capt = 0;
 487         unsigned int running, count1, count2;
 488         unsigned long flags;
 489
 490         spin_lock_irqsave(&cable->lock, flags);
 491         running = cable->running ^ cable->pause;
 492         if (running & (1 << SNDRV_PCM_STREAM_PLAYBACK)) {
 493                 delta_play = jiffies - dpcm_play->last_jiffies;
 494                 dpcm_play->last_jiffies += delta_play;
 495         }
 496
 497         if (running & (1 << SNDRV_PCM_STREAM_CAPTURE)) {
 498                 delta_capt = jiffies - dpcm_capt->last_jiffies;
 499                 dpcm_capt->last_jiffies += delta_capt;
 500         }
 501
 502         if (delta_play == 0 && delta_capt == 0)
 503                 goto unlock;
 504
 505         if (delta_play > delta_capt) {
 506                 count1 = bytepos_delta(dpcm_play, delta_play - delta_capt);
 507                 bytepos_finish(dpcm_play, count1);
 508                 delta_play = delta_capt;
 509         } else if (delta_play < delta_capt) {
 510                 count1 = bytepos_delta(dpcm_capt, delta_capt - delta_play);
 511                 clear_capture_buf(dpcm_capt, count1);
 512                 bytepos_finish(dpcm_capt, count1);
 513                 delta_capt = delta_play;
 514         }
 515
 516         if (delta_play == 0 && delta_capt == 0)
 517                 goto unlock;
 518
 519         /* note delta_capt == delta_play at this moment */
 520         count1 = bytepos_delta(dpcm_play, delta_play);
 521         count2 = bytepos_delta(dpcm_capt, delta_capt);
 522         if (count1 < count2) {
 523                 dpcm_capt->last_drift = count2 - count1;
 524                 count1 = count2;
 525         } else if (count1 > count2) {
 526                 dpcm_play->last_drift = count1 - count2;
 527         }
 528         copy_play_buf(dpcm_play, dpcm_capt, count1);
 529         bytepos_finish(dpcm_play, count1);
 530         bytepos_finish(dpcm_capt, count1);
 531  unlock:
 532         spin_unlock_irqrestore(&cable->lock, flags);
 533         return running;
 534 }
 535
 536 static void loopback_timer_function(unsigned long data)
 537 {
 538         struct loopback_pcm *dpcm = (struct loopback_pcm *)data;
 539         unsigned int running;
 540
 541         running = loopback_pos_update(dpcm->cable);
 542         if (running & (1 << dpcm->substream->stream)) {
 543                 loopback_timer_start(dpcm);
 544                 if (dpcm->period_update_pending) {
 545                         dpcm->period_update_pending = 0;
 546                         snd_pcm_period_elapsed(dpcm->substream);
 547                 }
 548         }
 549 }
 550
 551 static snd_pcm_uframes_t loopback_pointer(struct snd_pcm_substream *substream)
 552 {
 553         struct snd_pcm_runtime *runtime = substream->runtime;
 554         struct loopback_pcm *dpcm = runtime->private_data;
 555
 556         loopback_pos_update(dpcm->cable);
 557         return bytes_to_frames(runtime, dpcm->buf_pos);
 558 }
 559
 560 static struct snd_pcm_hardware loopback_pcm_hardware =
 561 {
 562         .info =         (SNDRV_PCM_INFO_INTERLEAVED | SNDRV_PCM_INFO_MMAP |
 563                          SNDRV_PCM_INFO_MMAP_VALID | SNDRV_PCM_INFO_PAUSE),
 564         .formats =      (SNDRV_PCM_FMTBIT_S16_LE | SNDRV_PCM_FMTBIT_S16_BE |
 565                          SNDRV_PCM_FMTBIT_S32_LE | SNDRV_PCM_FMTBIT_S32_BE |
 566                          SNDRV_PCM_FMTBIT_FLOAT_LE | SNDRV_PCM_FMTBIT_FLOAT_BE),
 567         .rates =        SNDRV_PCM_RATE_CONTINUOUS | SNDRV_PCM_RATE_8000_192000,
 568         .rate_min =             8000,
 569         .rate_max =             192000,
 570         .channels_min =         1,
 571         .channels_max =         32,
 572         .buffer_bytes_max =     2 * 1024 * 1024,
 573         .period_bytes_min =     64,
 574         /* note check overflow in frac_pos() using pcm_rate_shift before
 575            changing period_bytes_max value */
 576         .period_bytes_max =     1024 * 1024,
 577         .periods_min =          1,
 578         .periods_max =          1024,
 579         .fifo_size =            0,
 580 };
 581
 582 static void loopback_runtime_free(struct snd_pcm_runtime *runtime)
 583 {
 584         struct loopback_pcm *dpcm = runtime->private_data;
 585         kfree(dpcm);
 586 }
 587
 588 static int loopback_hw_params(struct snd_pcm_substream *substream,
 589                               struct snd_pcm_hw_params *params)
 590 {
 591         return snd_pcm_lib_alloc_vmalloc_buffer(substream,
 592                                                 params_buffer_bytes(params));
 593 }
 594
 595 static int loopback_hw_free(struct snd_pcm_substream *substream)
 596 {
 597         struct snd_pcm_runtime *runtime = substream->runtime;
 598         struct loopback_pcm *dpcm = runtime->private_data;
 599         struct loopback_cable *cable = dpcm->cable;
 600
 601         mutex_lock(&dpcm->loopback->cable_lock);
 602         cable->valid &= ~(1 << substream->stream);
 603         mutex_unlock(&dpcm->loopback->cable_lock);
 604         return snd_pcm_lib_free_vmalloc_buffer(substream);
 605 }
 606
 607 static unsigned int get_cable_index(struct snd_pcm_substream *substream)
 608 {
 609         if (!substream->pcm->device)
 610                 return substream->stream;
 611         else
 612                 return !substream->stream;
 613 }
 614
 615 static int rule_format(struct snd_pcm_hw_params *params,
 616                        struct snd_pcm_hw_rule *rule)
 617 {
 618
 619         struct snd_pcm_hardware *hw = rule->private;
 620         struct snd_mask *maskp = hw_param_mask(params, rule->var);
 621
 622         maskp->bits[0] &= (u_int32_t)hw->formats;
 623         maskp->bits[1] &= (u_int32_t)(hw->formats >> 32);
 624         memset(maskp->bits + 2, 0, (SNDRV_MASK_MAX-64) / 8); /* clear rest */
 625         if (! maskp->bits[0] && ! maskp->bits[1])
 626                 return -EINVAL;
 627         return 0;
 628 }
 629
 630 static int rule_rate(struct snd_pcm_hw_params *params,
 631                      struct snd_pcm_hw_rule *rule)
 632 {
 633         struct snd_pcm_hardware *hw = rule->private;
 634         struct snd_interval t;
 635
 636         t.min = hw->rate_min;
 637         t.max = hw->rate_max;
 638         t.openmin = t.openmax = 0;
 639         t.integer = 0;
 640         return snd_interval_refine(hw_param_interval(params, rule->var), &t);
 641 }
 642
 643 static int rule_channels(struct snd_pcm_hw_params *params,
 644                          struct snd_pcm_hw_rule *rule)
 645 {
 646         struct snd_pcm_hardware *hw = rule->private;
 647         struct snd_interval t;
 648
 649         t.min = hw->channels_min;
 650         t.max = hw->channels_max;
 651         t.openmin = t.openmax = 0;
 652         t.integer = 0;
 653         return snd_interval_refine(hw_param_interval(params, rule->var), &t);
 654 }
 655
 656 static int loopback_open(struct snd_pcm_substream *substream)
 657 {
 658         struct snd_pcm_runtime *runtime = substream->runtime;
 659         struct loopback *loopback = substream->private_data;
 660         struct loopback_pcm *dpcm;
 661         struct loopback_cable *cable;
 662         int err = 0;
 663         int dev = get_cable_index(substream);
 664
 665         mutex_lock(&loopback->cable_lock);
 666         dpcm = kzalloc(sizeof(*dpcm), GFP_KERNEL);
 667         if (!dpcm) {
 668                 err = -ENOMEM;
 669                 goto unlock;
 670         }
 671         dpcm->loopback = loopback;
 672         dpcm->substream = substream;
 673         setup_timer(&dpcm->timer, loopback_timer_function,
 674                     (unsigned long)dpcm);
 675         spin_lock_init(&dpcm->timer_lock);
 676
 677         cable = loopback->cables[substream->number][dev];
 678         if (!cable) {
 679                 cable = kzalloc(sizeof(*cable), GFP_KERNEL);
 680                 if (!cable) {
 681                         kfree(dpcm);
 682                         err = -ENOMEM;
 683                         goto unlock;
 684                 }
 685                 spin_lock_init(&cable->lock);
 686                 cable->hw = loopback_pcm_hardware;
 687                 loopback->cables[substream->number][dev] = cable;
 688         }
 689         dpcm->cable = cable;
 690         cable->streams[substream->stream] = dpcm;
 691
 692         snd_pcm_hw_constraint_integer(runtime, SNDRV_PCM_HW_PARAM_PERIODS);
 693
 694         /* use dynamic rules based on actual runtime->hw values */
 695         /* note that the default rules created in the PCM midlevel code */
 696         /* are cached -> they do not reflect the actual state */
 697         err = snd_pcm_hw_rule_add(runtime, 0,
 698                                   SNDRV_PCM_HW_PARAM_FORMAT,
 699                                   rule_format, &runtime->hw,
 700                                   SNDRV_PCM_HW_PARAM_FORMAT, -1);
 701         if (err < 0)
 702                 goto unlock;
 703         err = snd_pcm_hw_rule_add(runtime, 0,
 704                                   SNDRV_PCM_HW_PARAM_RATE,
 705                                   rule_rate, &runtime->hw,
 706                                   SNDRV_PCM_HW_PARAM_RATE, -1);
 707         if (err < 0)
 708                 goto unlock;
 709         err = snd_pcm_hw_rule_add(runtime, 0,
 710                                   SNDRV_PCM_HW_PARAM_CHANNELS,
 711                                   rule_channels, &runtime->hw,
 712                                   SNDRV_PCM_HW_PARAM_CHANNELS, -1);
 713         if (err < 0)
 714                 goto unlock;
 715
 716         runtime->private_data = dpcm;
 717         runtime->private_free = loopback_runtime_free;
 718         if (get_notify(dpcm))
 719                 runtime->hw = loopback_pcm_hardware;
 720         else
 721                 runtime->hw = cable->hw;
 722  unlock:
 723         mutex_unlock(&loopback->cable_lock);
 724         return err;
 725 }
 726
 727 static int loopback_close(struct snd_pcm_substream *substream)
 728 {
 729         struct loopback *loopback = substream->private_data;
 730         struct loopback_pcm *dpcm = substream->runtime->private_data;
 731         struct loopback_cable *cable;
 732         int dev = get_cable_index(substream);
 733
 734         loopback_timer_stop(dpcm);
 735         mutex_lock(&loopback->cable_lock);
 736         cable = loopback->cables[substream->number][dev];
 737         if (cable->streams[!substream->stream]) {
 738                 /* other stream is still alive */
 739                 cable->streams[substream->stream] = NULL;
 740         } else {
 741                 /* free the cable */
 742                 loopback->cables[substream->number][dev] = NULL;
 743                 kfree(cable);
 744         }
 745         mutex_unlock(&loopback->cable_lock);
 746         return 0;
 747 }
 748
 749 static struct snd_pcm_ops loopback_playback_ops = {
 750         .open =         loopback_open,
 751         .close =        loopback_close,
 752         .ioctl =        snd_pcm_lib_ioctl,
 753         .hw_params =    loopback_hw_params,
 754         .hw_free =      loopback_hw_free,
 755         .prepare =      loopback_prepare,
 756         .trigger =      loopback_trigger,
 757         .pointer =      loopback_pointer,
 758         .page =         snd_pcm_lib_get_vmalloc_page,
 759         .mmap =         snd_pcm_lib_mmap_vmalloc,
 760 };
 761
 762 static struct snd_pcm_ops loopback_capture_ops = {
 763         .open =         loopback_open,
 764         .close =        loopback_close,
 765         .ioctl =        snd_pcm_lib_ioctl,
 766         .hw_params =    loopback_hw_params,
 767         .hw_free =      loopback_hw_free,
 768         .prepare =      loopback_prepare,
 769         .trigger =      loopback_trigger,
 770         .pointer =      loopback_pointer,
 771         .page =         snd_pcm_lib_get_vmalloc_page,
 772         .mmap =         snd_pcm_lib_mmap_vmalloc,
 773 };
 774
 775 static int __devinit loopback_pcm_new(struct loopback *loopback,
 776                                       int device, int substreams)
 777 {
 778         struct snd_pcm *pcm;
 779         int err;
 780
 781         err = snd_pcm_new(loopback->card, "Loopback PCM", device,
 782                           substreams, substreams, &pcm);
 783         if (err < 0)
 784                 return err;
 785         snd_pcm_set_ops(pcm, SNDRV_PCM_STREAM_PLAYBACK, &loopback_playback_ops);
 786         snd_pcm_set_ops(pcm, SNDRV_PCM_STREAM_CAPTURE, &loopback_capture_ops);
 787
 788         pcm->private_data = loopback;
 789         pcm->info_flags = 0;
 790         strcpy(pcm->name, "Loopback PCM");
 791
 792         loopback->pcm[device] = pcm;
 793         return 0;
 794 }
 795
 796 static int loopback_rate_shift_info(struct snd_kcontrol *kcontrol,
 797                                     struct snd_ctl_elem_info *uinfo)
 798 {
 799         uinfo->type = SNDRV_CTL_ELEM_TYPE_INTEGER;
 800         uinfo->count = 1;
 801         uinfo->value.integer.min = 80000;
 802         uinfo->value.integer.max = 120000;
 803         uinfo->value.integer.step = 1;
 804         return 0;
 805 }
 806
 807 static int loopback_rate_shift_get(struct snd_kcontrol *kcontrol,
 808                                    struct snd_ctl_elem_value *ucontrol)
 809 {
 810         struct loopback *loopback = snd_kcontrol_chip(kcontrol);
 811
 812         ucontrol->value.integer.value[0] =
 813                 loopback->setup[kcontrol->id.subdevice]
 814                                [kcontrol->id.device].rate_shift;
 815         return 0;
 816 }
 817
 818 static int loopback_rate_shift_put(struct snd_kcontrol *kcontrol,
 819                                    struct snd_ctl_elem_value *ucontrol)
 820 {
 821         struct loopback *loopback = snd_kcontrol_chip(kcontrol);
 822         unsigned int val;
 823         int change = 0;
 824
 825         val = ucontrol->value.integer.value[0];
 826         if (val < 80000)
 827                 val = 80000;
 828         if (val > 120000)
 829                 val = 120000;
 830         mutex_lock(&loopback->cable_lock);
 831         if (val != loopback->setup[kcontrol->id.subdevice]
 832                                   [kcontrol->id.device].rate_shift) {
 833                 loopback->setup[kcontrol->id.subdevice]
 834                                [kcontrol->id.device].rate_shift = val;
 835                 change = 1;
 836         }
 837         mutex_unlock(&loopback->cable_lock);
 838         return change;
 839 }
 840
 841 static int loopback_notify_get(struct snd_kcontrol *kcontrol,
 842                                struct snd_ctl_elem_value *ucontrol)
 843 {
 844         struct loopback *loopback = snd_kcontrol_chip(kcontrol);
 845
 846         ucontrol->value.integer.value[0] =
 847                 loopback->setup[kcontrol->id.subdevice]
 848                                [kcontrol->id.device].notify;
 849         return 0;
 850 }
 851
 852 static int loopback_notify_put(struct snd_kcontrol *kcontrol,
 853                                struct snd_ctl_elem_value *ucontrol)
 854 {
 855         struct loopback *loopback = snd_kcontrol_chip(kcontrol);
 856         unsigned int val;
 857         int change = 0;
 858
 859         val = ucontrol->value.integer.value[0] ? 1 : 0;
 860         if (val != loopback->setup[kcontrol->id.subdevice]
 861                                 [kcontrol->id.device].notify) {
 862                 loopback->setup[kcontrol->id.subdevice]
 863                         [kcontrol->id.device].notify = val;
 864                 change = 1;
 865         }
 866         return change;
 867 }
 868
 869 static int loopback_active_get(struct snd_kcontrol *kcontrol,
 870                                struct snd_ctl_elem_value *ucontrol)
 871 {
 872         struct loopback *loopback = snd_kcontrol_chip(kcontrol);
 873         struct loopback_cable *cable = loopback->cables
 874                         [kcontrol->id.subdevice][kcontrol->id.device ^ 1];
 875         unsigned int val = 0;
 876
 877         if (cable != NULL)
 878                 val = (cable->running & (1 << SNDRV_PCM_STREAM_PLAYBACK)) ?
 879                                                                         1 : 0;
 880         ucontrol->value.integer.value[0] = val;
 881         return 0;
 882 }
 883
 884 static int loopback_format_info(struct snd_kcontrol *kcontrol,
 885                                 struct snd_ctl_elem_info *uinfo)
 886 {
 887         uinfo->type = SNDRV_CTL_ELEM_TYPE_INTEGER;
 888         uinfo->count = 1;
 889         uinfo->value.integer.min = 0;
 890         uinfo->value.integer.max = SNDRV_PCM_FORMAT_LAST;
 891         uinfo->value.integer.step = 1;
 892         return 0;
 893 }
 894
 895 static int loopback_format_get(struct snd_kcontrol *kcontrol,
 896                                struct snd_ctl_elem_value *ucontrol)
 897 {
 898         struct loopback *loopback = snd_kcontrol_chip(kcontrol);
 899
 900         ucontrol->value.integer.value[0] =
 901                 loopback->setup[kcontrol->id.subdevice]
 902                                [kcontrol->id.device].format;
 903         return 0;
 904 }
 905
 906 static int loopback_rate_info(struct snd_kcontrol *kcontrol,
 907                               struct snd_ctl_elem_info *uinfo)
 908 {
 909         uinfo->type = SNDRV_CTL_ELEM_TYPE_INTEGER;
 910         uinfo->count = 1;
 911         uinfo->value.integer.min = 0;
 912         uinfo->value.integer.max = 192000;
 913         uinfo->value.integer.step = 1;
 914         return 0;
 915 }
 916
 917 static int loopback_rate_get(struct snd_kcontrol *kcontrol,
 918                              struct snd_ctl_elem_value *ucontrol)
 919 {
 920         struct loopback *loopback = snd_kcontrol_chip(kcontrol);
 921
 922         ucontrol->value.integer.value[0] =
 923                 loopback->setup[kcontrol->id.subdevice]
 924                                [kcontrol->id.device].rate;
 925         return 0;
 926 }
 927
 928 static int loopback_channels_info(struct snd_kcontrol *kcontrol,
 929                                   struct snd_ctl_elem_info *uinfo)
 930 {
 931         uinfo->type = SNDRV_CTL_ELEM_TYPE_INTEGER;
 932         uinfo->count = 1;
 933         uinfo->value.integer.min = 1;
 934         uinfo->value.integer.max = 1024;
 935         uinfo->value.integer.step = 1;
 936         return 0;
 937 }
 938
 939 static int loopback_channels_get(struct snd_kcontrol *kcontrol,
 940                                  struct snd_ctl_elem_value *ucontrol)
 941 {
 942         struct loopback *loopback = snd_kcontrol_chip(kcontrol);
 943
 944         ucontrol->value.integer.value[0] =
 945                 loopback->setup[kcontrol->id.subdevice]
 946                                [kcontrol->id.device].channels;
 947         return 0;
 948 }
 949
 950 static struct snd_kcontrol_new loopback_controls[]  __devinitdata = {
 951 {
 952         .iface =        SNDRV_CTL_ELEM_IFACE_PCM,
 953         .name =         "PCM Rate Shift 100000",
 954         .info =         loopback_rate_shift_info,
 955         .get =          loopback_rate_shift_get,
 956         .put =          loopback_rate_shift_put,
 957 },
 958 {
 959         .iface =        SNDRV_CTL_ELEM_IFACE_PCM,
 960         .name =         "PCM Notify",
 961         .info =         snd_ctl_boolean_mono_info,
 962         .get =          loopback_notify_get,
 963         .put =          loopback_notify_put,
 964 },
 965 #define ACTIVE_IDX 2
 966 {
 967         .access =       SNDRV_CTL_ELEM_ACCESS_READ,
 968         .iface =        SNDRV_CTL_ELEM_IFACE_PCM,
 969         .name =         "PCM Slave Active",
 970         .info =         snd_ctl_boolean_mono_info,
 971         .get =          loopback_active_get,
 972 },
 973 #define FORMAT_IDX 3
 974 {
 975         .access =       SNDRV_CTL_ELEM_ACCESS_READ,
 976         .iface =        SNDRV_CTL_ELEM_IFACE_PCM,
 977         .name =         "PCM Slave Format",
 978         .info =         loopback_format_info,
 979         .get =          loopback_format_get
 980 },
 981 #define RATE_IDX 4
 982 {
 983         .access =       SNDRV_CTL_ELEM_ACCESS_READ,
 984         .iface =        SNDRV_CTL_ELEM_IFACE_PCM,
 985         .name =         "PCM Slave Rate",
 986         .info =         loopback_rate_info,
 987         .get =          loopback_rate_get
 988 },
 989 #define CHANNELS_IDX 5
 990 {
 991         .access =       SNDRV_CTL_ELEM_ACCESS_READ,
 992         .iface =        SNDRV_CTL_ELEM_IFACE_PCM,
 993         .name =         "PCM Slave Channels",
 994         .info =         loopback_channels_info,
 995         .get =          loopback_channels_get
 996 }
 997 };
 998
 999 static int __devinit loopback_mixer_new(struct loopback *loopback, int notify)
1000 {
1001         struct snd_card *card = loopback->card;
1002         struct snd_pcm *pcm;
1003         struct snd_kcontrol *kctl;
1004         struct loopback_setup *setup;
1005         int err, dev, substr, substr_count, idx;
1006
1007         strcpy(card->mixername, "Loopback Mixer");
1008         for (dev = 0; dev < 2; dev++) {
1009                 pcm = loopback->pcm[dev];
1010                 substr_count =
1011                     pcm->streams[SNDRV_PCM_STREAM_CAPTURE].substream_count;
1012                 for (substr = 0; substr < substr_count; substr++) {
1013                         setup = &loopback->setup[substr][dev];
1014                         setup->notify = notify;
1015                         setup->rate_shift = NO_PITCH;
1016                         setup->format = SNDRV_PCM_FORMAT_S16_LE;
1017                         setup->rate = 48000;
1018                         setup->channels = 2;
1019                         for (idx = 0; idx < ARRAY_SIZE(loopback_controls);
1020                                                                         idx++) {
1021                                 kctl = snd_ctl_new1(&loopback_controls[idx],
1022                                                     loopback);
1023                                 if (!kctl)
1024                                         return -ENOMEM;
1025                                 kctl->id.device = dev;
1026                                 kctl->id.subdevice = substr;
1027                                 switch (idx) {
1028                                 case ACTIVE_IDX:
1029                                         setup->active_id = kctl->id;
1030                                         break;
1031                                 case FORMAT_IDX:
1032                                         setup->format_id = kctl->id;
1033                                         break;
1034                                 case RATE_IDX:
1035                                         setup->rate_id = kctl->id;
1036                                         break;
1037                                 case CHANNELS_IDX:
1038                                         setup->channels_id = kctl->id;
1039                                         break;
1040                                 default:
1041                                         break;
1042                                 }
1043                                 err = snd_ctl_add(card, kctl);
1044                                 if (err < 0)
1045                                         return err;
1046                         }
1047                 }
1048         }
1049         return 0;
1050 }
1051
1052 #ifdef CONFIG_PROC_FS
1053
1054 static void print_dpcm_info(struct snd_info_buffer *buffer,
1055                             struct loopback_pcm *dpcm,
1056                             const char *id)
1057 {
1058         snd_iprintf(buffer, "  %s\n", id);
1059         if (dpcm == NULL) {
1060                 snd_iprintf(buffer, "    inactive\n");
1061                 return;
1062         }
1063         snd_iprintf(buffer, "    buffer_size:\t%u\n", dpcm->pcm_buffer_size);
1064         snd_iprintf(buffer, "    buffer_pos:\t\t%u\n", dpcm->buf_pos);
1065         snd_iprintf(buffer, "    silent_size:\t%u\n", dpcm->silent_size);
1066         snd_iprintf(buffer, "    period_size:\t%u\n", dpcm->pcm_period_size);
1067         snd_iprintf(buffer, "    bytes_per_sec:\t%u\n", dpcm->pcm_bps);
1068         snd_iprintf(buffer, "    sample_align:\t%u\n", dpcm->pcm_salign);
1069         snd_iprintf(buffer, "    rate_shift:\t\t%u\n", dpcm->pcm_rate_shift);
1070         snd_iprintf(buffer, "    update_pending:\t%u\n",
1071                                                 dpcm->period_update_pending);
1072         snd_iprintf(buffer, "    irq_pos:\t\t%u\n", dpcm->irq_pos);
1073         snd_iprintf(buffer, "    period_frac:\t%u\n", dpcm->period_size_frac);
1074         snd_iprintf(buffer, "    last_jiffies:\t%lu (%lu)\n",
1075                                         dpcm->last_jiffies, jiffies);
1076         snd_iprintf(buffer, "    timer_expires:\t%lu\n", dpcm->timer.expires);
1077 }
1078
1079 static void print_substream_info(struct snd_info_buffer *buffer,
1080                                  struct loopback *loopback,
1081                                  int sub,
1082                                  int num)
1083 {
1084         struct loopback_cable *cable = loopback->cables[sub][num];
1085
1086         snd_iprintf(buffer, "Cable %i substream %i:\n", num, sub);
1087         if (cable == NULL) {
1088                 snd_iprintf(buffer, "  inactive\n");
1089                 return;
1090         }
1091         snd_iprintf(buffer, "  valid: %u\n", cable->valid);
1092         snd_iprintf(buffer, "  running: %u\n", cable->running);
1093         snd_iprintf(buffer, "  pause: %u\n", cable->pause);
1094         print_dpcm_info(buffer, cable->streams[0], "Playback");
1095         print_dpcm_info(buffer, cable->streams[1], "Capture");
1096 }
1097
1098 static void print_cable_info(struct snd_info_entry *entry,
1099                              struct snd_info_buffer *buffer)
1100 {
1101         struct loopback *loopback = entry->private_data;
1102         int sub, num;
1103
1104         mutex_lock(&loopback->cable_lock);
1105         num = entry->name[strlen(entry->name)-1];
1106         num = num == '0' ? 0 : 1;
1107         for (sub = 0; sub < MAX_PCM_SUBSTREAMS; sub++)
1108                 print_substream_info(buffer, loopback, sub, num);
1109         mutex_unlock(&loopback->cable_lock);
1110 }
1111
1112 static int __devinit loopback_proc_new(struct loopback *loopback, int cidx)
1113 {
1114         char name[32];
1115         struct snd_info_entry *entry;
1116         int err;
1117
1118         snprintf(name, sizeof(name), "cable#%d", cidx);
1119         err = snd_card_proc_new(loopback->card, name, &entry);
1120         if (err < 0)
1121                 return err;
1122
1123         snd_info_set_text_ops(entry, loopback, print_cable_info);
1124         return 0;
1125 }
1126
1127 #else /* !CONFIG_PROC_FS */
1128
1129 #define loopback_proc_new(loopback, cidx) do { } while (0)
1130
1131 #endif
1132
1133 static int __devinit loopback_probe(struct platform_device *devptr)
1134 {
1135         struct snd_card *card;
1136         struct loopback *loopback;
1137         int dev = devptr->id;
1138         int err;
1139
1140         err = snd_card_create(index[dev], id[dev], THIS_MODULE,
1141                               sizeof(struct loopback), &card);
1142         if (err < 0)
1143                 return err;
1144         loopback = card->private_data;
1145
1146         if (pcm_substreams[dev] < 1)
1147                 pcm_substreams[dev] = 1;
1148         if (pcm_substreams[dev] > MAX_PCM_SUBSTREAMS)
1149                 pcm_substreams[dev] = MAX_PCM_SUBSTREAMS;
1150
1151         loopback->card = card;
1152         mutex_init(&loopback->cable_lock);
1153
1154         err = loopback_pcm_new(loopback, 0, pcm_substreams[dev]);
1155         if (err < 0)
1156                 goto __nodev;
1157         err = loopback_pcm_new(loopback, 1, pcm_substreams[dev]);
1158         if (err < 0)
1159                 goto __nodev;
1160         err = loopback_mixer_new(loopback, pcm_notify[dev] ? 1 : 0);
1161         if (err < 0)
1162                 goto __nodev;
1163         loopback_proc_new(loopback, 0);
1164         loopback_proc_new(loopback, 1);
1165         strcpy(card->driver, "Loopback");
1166         strcpy(card->shortname, "Loopback");
1167         sprintf(card->longname, "Loopback %i", dev + 1);
1168         err = snd_card_register(card);
1169         if (!err) {
1170                 platform_set_drvdata(devptr, card);
1171                 return 0;
1172         }
1173       __nodev:
1174         snd_card_free(card);
1175         return err;
1176 }
1177
1178 static int __devexit loopback_remove(struct platform_device *devptr)
1179 {
1180         snd_card_free(platform_get_drvdata(devptr));
1181         platform_set_drvdata(devptr, NULL);
1182         return 0;
1183 }
1184
1185 #ifdef CONFIG_PM_SLEEP
1186 static int loopback_suspend(struct device *pdev)
1187 {
1188         struct snd_card *card = dev_get_drvdata(pdev);
1189         struct loopback *loopback = card->private_data;
1190
1191         snd_power_change_state(card, SNDRV_CTL_POWER_D3hot);
1192
1193         snd_pcm_suspend_all(loopback->pcm[0]);
1194         snd_pcm_suspend_all(loopback->pcm[1]);
1195         return 0;
1196 }
1197
1198 static int loopback_resume(struct device *pdev)
1199 {
1200         struct snd_card *card = dev_get_drvdata(pdev);
1201
1202         snd_power_change_state(card, SNDRV_CTL_POWER_D0);
1203         return 0;
1204 }
1205
1206 static SIMPLE_DEV_PM_OPS(loopback_pm, loopback_suspend, loopback_resume);
1207 #define LOOPBACK_PM_OPS &loopback_pm
1208 #else
1209 #define LOOPBACK_PM_OPS NULL
1210 #endif
1211
1212 #define SND_LOOPBACK_DRIVER     "snd_aloop"
1213
1214 static struct platform_driver loopback_driver = {
1215         .probe          = loopback_probe,
1216         .remove         = __devexit_p(loopback_remove),
1217         .driver         = {
1218                 .name   = SND_LOOPBACK_DRIVER,
1219                 .owner  = THIS_MODULE,
1220                 .pm     = LOOPBACK_PM_OPS,
1221         },
1222 };
1223
1224 static void loopback_unregister_all(void)
1225 {
1226         int i;
1227
1228         for (i = 0; i < ARRAY_SIZE(devices); ++i)
1229                 platform_device_unregister(devices[i]);
1230         platform_driver_unregister(&loopback_driver);
1231 }
1232
1233 static int __init alsa_card_loopback_init(void)
1234 {
1235         int i, err, cards;
1236
1237         err = platform_driver_register(&loopback_driver);
1238         if (err < 0)
1239                 return err;
1240
1241
1242         cards = 0;
1243         for (i = 0; i < SNDRV_CARDS; i++) {
1244                 struct platform_device *device;
1245                 if (!enable[i])
1246                         continue;
1247                 device = platform_device_register_simple(SND_LOOPBACK_DRIVER,
1248                                                          i, NULL, 0);
1249                 if (IS_ERR(device))
1250                         continue;
1251                 if (!platform_get_drvdata(device)) {
1252                         platform_device_unregister(device);
1253                         continue;
1254                 }
1255                 devices[i] = device;
1256                 cards++;
1257         }
1258         if (!cards) {
1259 #ifdef MODULE
1260                 printk(KERN_ERR "aloop: No loopback enabled\n");
1261 #endif
1262                 loopback_unregister_all();
1263                 return -ENODEV;
1264         }
1265         return 0;
1266 }
1267
1268 static void __exit alsa_card_loopback_exit(void)
1269 {
1270         loopback_unregister_all();
1271 }
1272
1273 module_init(alsa_card_loopback_init)
1274 module_exit(alsa_card_loopback_exit)