sound/drivers/aloop.c

   1 /*
   2  *  Loopback soundcard
   3  *
   4  *  Original code:
   5  *  Copyright (c) by Jaroslav Kysela <perex@perex.cz>
   6  *
   7  *  More accurate positioning and full-duplex support:
   8  *  Copyright (c) Ahmet İnan <ainan at mathematik.uni-freiburg.de>
   9  *
  10  *  Major (almost complete) rewrite:
  11  *  Copyright (c) by Takashi Iwai <tiwai@suse.de>
  12  *
  13  *  A next major update in 2010 (separate timers for playback and capture):
  14  *  Copyright (c) Jaroslav Kysela <perex@perex.cz>
  15  *
  16  *   This program is free software; you can redistribute it and/or modify
  17  *   it under the terms of the GNU General Public License as published by
  18  *   the Free Software Foundation; either version 2 of the License, or
  19  *   (at your option) any later version.
  20  *
  21  *   This program is distributed in the hope that it will be useful,
  22  *   but WITHOUT ANY WARRANTY; without even the implied warranty of
  23  *   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  24  *   GNU General Public License for more details.
  25  *
  26  *   You should have received a copy of the GNU General Public License
  27  *   along with this program; if not, write to the Free Software
  28  *   Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307 USA
  29  *
  30  */
  31
  32 #include <linux/init.h>
  33 #include <linux/jiffies.h>
  34 #include <linux/slab.h>
  35 #include <linux/time.h>
  36 #include <linux/wait.h>
  37 #include <linux/module.h>
  38 #include <linux/platform_device.h>
  39 #include <sound/core.h>
  40 #include <sound/control.h>
  41 #include <sound/pcm.h>
  42 #include <sound/info.h>
  43 #include <sound/initval.h>
  44
  45 MODULE_AUTHOR("Jaroslav Kysela <perex@perex.cz>");
  46 MODULE_DESCRIPTION("A loopback soundcard");
  47 MODULE_LICENSE("GPL");
  48 MODULE_SUPPORTED_DEVICE("{{ALSA,Loopback soundcard}}");
  49
  50 #define MAX_PCM_SUBSTREAMS      8
  51
  52 static int index[SNDRV_CARDS] = SNDRV_DEFAULT_IDX;      /* Index 0-MAX */
  53 static char *id[SNDRV_CARDS] = SNDRV_DEFAULT_STR;       /* ID for this card */
  54 static bool enable[SNDRV_CARDS] = {1, [1 ... (SNDRV_CARDS - 1)] = 0};
  55 static int pcm_substreams[SNDRV_CARDS] = {[0 ... (SNDRV_CARDS - 1)] = 8};
  56 static int pcm_notify[SNDRV_CARDS];
  57
  58 module_param_array(index, int, NULL, 0444);
  59 MODULE_PARM_DESC(index, "Index value for loopback soundcard.");
  60 module_param_array(id, charp, NULL, 0444);
  61 MODULE_PARM_DESC(id, "ID string for loopback soundcard.");
  62 module_param_array(enable, bool, NULL, 0444);
  63 MODULE_PARM_DESC(enable, "Enable this loopback soundcard.");
  64 module_param_array(pcm_substreams, int, NULL, 0444);
  65 MODULE_PARM_DESC(pcm_substreams, "PCM substreams # (1-8) for loopback driver.");
  66 module_param_array(pcm_notify, int, NULL, 0444);
  67 MODULE_PARM_DESC(pcm_notify, "Break capture when PCM format/rate/channels changes.");
  68
  69 #define NO_PITCH 100000
  70
  71 struct loopback_pcm;
  72
  73 struct loopback_cable {
  74         spinlock_t lock;
  75         struct loopback_pcm *streams[2];
  76         struct snd_pcm_hardware hw;
  77         /* flags */
  78         unsigned int valid;
  79         unsigned int running;
  80         unsigned int pause;
  81 };
  82
  83 struct loopback_setup {
  84         unsigned int notify: 1;
  85         unsigned int rate_shift;
  86         unsigned int format;
  87         unsigned int rate;
  88         unsigned int channels;
  89         struct snd_ctl_elem_id active_id;
  90         struct snd_ctl_elem_id format_id;
  91         struct snd_ctl_elem_id rate_id;
  92         struct snd_ctl_elem_id channels_id;
  93 };
  94
  95 struct loopback {
  96         struct snd_card *card;
  97         struct mutex cable_lock;
  98         struct loopback_cable *cables[MAX_PCM_SUBSTREAMS][2];
  99         struct snd_pcm *pcm[2];
 100         struct loopback_setup setup[MAX_PCM_SUBSTREAMS][2];
 101 };
 102
 103 struct loopback_pcm {
 104         struct loopback *loopback;
 105         struct snd_pcm_substream *substream;
 106         struct loopback_cable *cable;
 107         unsigned int pcm_buffer_size;
 108         unsigned int buf_pos;   /* position in buffer */
 109         unsigned int silent_size;
 110         /* PCM parameters */
 111         unsigned int pcm_period_size;
 112         unsigned int pcm_bps;           /* bytes per second */
 113         unsigned int pcm_salign;        /* bytes per sample * channels */
 114         unsigned int pcm_rate_shift;    /* rate shift value */
 115         /* flags */
 116         unsigned int period_update_pending :1;
 117         /* timer stuff */
 118         unsigned int irq_pos;           /* fractional IRQ position */
 119         unsigned int period_size_frac;
 120         unsigned int last_drift;
 121         unsigned long last_jiffies;
 122         struct timer_list timer;
 123 };
 124
 125 static struct platform_device *devices[SNDRV_CARDS];
 126
 127 static inline unsigned int byte_pos(struct loopback_pcm *dpcm, unsigned int x)
 128 {
 129         if (dpcm->pcm_rate_shift == NO_PITCH) {
 130                 x /= HZ;
 131         } else {
 132                 x = div_u64(NO_PITCH * (unsigned long long)x,
 133                             HZ * (unsigned long long)dpcm->pcm_rate_shift);
 134         }
 135         return x - (x % dpcm->pcm_salign);
 136 }
 137
 138 static inline unsigned int frac_pos(struct loopback_pcm *dpcm, unsigned int x)
 139 {
 140         if (dpcm->pcm_rate_shift == NO_PITCH) { /* no pitch */
 141                 return x * HZ;
 142         } else {
 143                 x = div_u64(dpcm->pcm_rate_shift * (unsigned long long)x * HZ,
 144                             NO_PITCH);
 145         }
 146         return x;
 147 }
 148
 149 static inline struct loopback_setup *get_setup(struct loopback_pcm *dpcm)
 150 {
 151         int device = dpcm->substream->pstr->pcm->device;
 152
 153         if (dpcm->substream->stream == SNDRV_PCM_STREAM_PLAYBACK)
 154                 device ^= 1;
 155         return &dpcm->loopback->setup[dpcm->substream->number][device];
 156 }
 157
 158 static inline unsigned int get_notify(struct loopback_pcm *dpcm)
 159 {
 160         return get_setup(dpcm)->notify;
 161 }
 162
 163 static inline unsigned int get_rate_shift(struct loopback_pcm *dpcm)
 164 {
 165         return get_setup(dpcm)->rate_shift;
 166 }
 167
 168 /* call in cable->lock */
 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         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 }
 187
 188 /* call in cable->lock */
 189 static inline void loopback_timer_stop(struct loopback_pcm *dpcm)
 190 {
 191         del_timer(&dpcm->timer);
 192         dpcm->timer.expires = 0;
 193 }
 194
 195 #define CABLE_VALID_PLAYBACK    (1 << SNDRV_PCM_STREAM_PLAYBACK)
 196 #define CABLE_VALID_CAPTURE     (1 << SNDRV_PCM_STREAM_CAPTURE)
 197 #define CABLE_VALID_BOTH        (CABLE_VALID_PLAYBACK|CABLE_VALID_CAPTURE)
 198
 199 static int loopback_check_format(struct loopback_cable *cable, int stream)
 200 {
 201         struct snd_pcm_runtime *runtime, *cruntime;
 202         struct loopback_setup *setup;
 203         struct snd_card *card;
 204         int check;
 205
 206         if (cable->valid != CABLE_VALID_BOTH) {
 207                 if (stream == SNDRV_PCM_STREAM_PLAYBACK)
 208                         goto __notify;
 209                 return 0;
 210         }
 211         runtime = cable->streams[SNDRV_PCM_STREAM_PLAYBACK]->
 212                                                         substream->runtime;
 213         cruntime = cable->streams[SNDRV_PCM_STREAM_CAPTURE]->
 214                                                         substream->runtime;
 215         check = runtime->format != cruntime->format ||
 216                 runtime->rate != cruntime->rate ||
 217                 runtime->channels != cruntime->channels;
 218         if (!check)
 219                 return 0;
 220         if (stream == SNDRV_PCM_STREAM_CAPTURE) {
 221                 return -EIO;
 222         } else {
 223                 snd_pcm_stop(cable->streams[SNDRV_PCM_STREAM_CAPTURE]->
 224                                         substream, SNDRV_PCM_STATE_DRAINING);
 225               __notify:
 226                 runtime = cable->streams[SNDRV_PCM_STREAM_PLAYBACK]->
 227                                                         substream->runtime;
 228                 setup = get_setup(cable->streams[SNDRV_PCM_STREAM_PLAYBACK]);
 229                 card = cable->streams[SNDRV_PCM_STREAM_PLAYBACK]->loopback->card;
 230                 if (setup->format != runtime->format) {
 231                         snd_ctl_notify(card, SNDRV_CTL_EVENT_MASK_VALUE,
 232                                                         &setup->format_id);
 233                         setup->format = runtime->format;
 234                 }
 235                 if (setup->rate != runtime->rate) {
 236                         snd_ctl_notify(card, SNDRV_CTL_EVENT_MASK_VALUE,
 237                                                         &setup->rate_id);
 238                         setup->rate = runtime->rate;
 239                 }
 240                 if (setup->channels != runtime->channels) {
 241                         snd_ctl_notify(card, SNDRV_CTL_EVENT_MASK_VALUE,
 242                                                         &setup->channels_id);
 243                         setup->channels = runtime->channels;
 244                 }
 245         }
 246         return 0;
 247 }
 248
 249 static void loopback_active_notify(struct loopback_pcm *dpcm)
 250 {
 251         snd_ctl_notify(dpcm->loopback->card,
 252                        SNDRV_CTL_EVENT_MASK_VALUE,
 253                        &get_setup(dpcm)->active_id);
 254 }
 255
 256 static int loopback_trigger(struct snd_pcm_substream *substream, int cmd)
 257 {
 258         struct snd_pcm_runtime *runtime = substream->runtime;
 259         struct loopback_pcm *dpcm = runtime->private_data;
 260         struct loopback_cable *cable = dpcm->cable;
 261         int err, stream = 1 << substream->stream;
 262
 263         switch (cmd) {
 264         case SNDRV_PCM_TRIGGER_START:
 265                 err = loopback_check_format(cable, substream->stream);
 266                 if (err < 0)
 267                         return err;
 268                 dpcm->last_jiffies = jiffies;
 269                 dpcm->pcm_rate_shift = 0;
 270                 dpcm->last_drift = 0;
 271                 spin_lock(&cable->lock);
 272                 cable->running |= stream;
 273                 cable->pause &= ~stream;
 274                 loopback_timer_start(dpcm);
 275                 spin_unlock(&cable->lock);
 276                 if (substream->stream == SNDRV_PCM_STREAM_PLAYBACK)
 277                         loopback_active_notify(dpcm);
 278                 break;
 279         case SNDRV_PCM_TRIGGER_STOP:
 280                 spin_lock(&cable->lock);
 281                 cable->running &= ~stream;
 282                 cable->pause &= ~stream;
 283                 loopback_timer_stop(dpcm);
 284                 spin_unlock(&cable->lock);
 285                 if (substream->stream == SNDRV_PCM_STREAM_PLAYBACK)
 286                         loopback_active_notify(dpcm);
 287                 break;
 288         case SNDRV_PCM_TRIGGER_PAUSE_PUSH:
 289         case SNDRV_PCM_TRIGGER_SUSPEND:
 290                 spin_lock(&cable->lock);
 291                 cable->pause |= stream;
 292                 loopback_timer_stop(dpcm);
 293                 spin_unlock(&cable->lock);
 294                 break;
 295         case SNDRV_PCM_TRIGGER_PAUSE_RELEASE:
 296         case SNDRV_PCM_TRIGGER_RESUME:
 297                 spin_lock(&cable->lock);
 298                 dpcm->last_jiffies = jiffies;
 299                 cable->pause &= ~stream;
 300                 loopback_timer_start(dpcm);
 301                 spin_unlock(&cable->lock);
 302                 break;
 303         default:
 304                 return -EINVAL;
 305         }
 306         return 0;
 307 }
 308
 309 static void params_change_substream(struct loopback_pcm *dpcm,
 310                                     struct snd_pcm_runtime *runtime)
 311 {
 312         struct snd_pcm_runtime *dst_runtime;
 313
 314         if (dpcm == NULL || dpcm->substream == NULL)
 315                 return;
 316         dst_runtime = dpcm->substream->runtime;
 317         if (dst_runtime == NULL)
 318                 return;
 319         dst_runtime->hw = dpcm->cable->hw;
 320 }
 321
 322 static void params_change(struct snd_pcm_substream *substream)
 323 {
 324         struct snd_pcm_runtime *runtime = substream->runtime;
 325         struct loopback_pcm *dpcm = runtime->private_data;
 326         struct loopback_cable *cable = dpcm->cable;
 327
 328         cable->hw.formats = pcm_format_to_bits(runtime->format);
 329         cable->hw.rate_min = runtime->rate;
 330         cable->hw.rate_max = runtime->rate;
 331         cable->hw.channels_min = runtime->channels;
 332         cable->hw.channels_max = runtime->channels;
 333         params_change_substream(cable->streams[SNDRV_PCM_STREAM_PLAYBACK],
 334                                 runtime);
 335         params_change_substream(cable->streams[SNDRV_PCM_STREAM_CAPTURE],
 336                                 runtime);
 337 }
 338
 339 static int loopback_prepare(struct snd_pcm_substream *substream)
 340 {
 341         struct snd_pcm_runtime *runtime = substream->runtime;
 342         struct loopback_pcm *dpcm = runtime->private_data;
 343         struct loopback_cable *cable = dpcm->cable;
 344         int bps, salign;
 345
 346         salign = (snd_pcm_format_width(runtime->format) *
 347                                                 runtime->channels) / 8;
 348         bps = salign * runtime->rate;
 349         if (bps <= 0 || salign <= 0)
 350                 return -EINVAL;
 351
 352         dpcm->buf_pos = 0;
 353         dpcm->pcm_buffer_size = frames_to_bytes(runtime, runtime->buffer_size);
 354         if (substream->stream == SNDRV_PCM_STREAM_CAPTURE) {
 355                 /* clear capture buffer */
 356                 dpcm->silent_size = dpcm->pcm_buffer_size;
 357                 snd_pcm_format_set_silence(runtime->format, runtime->dma_area,
 358                                            runtime->buffer_size * runtime->channels);
 359         }
 360
 361         dpcm->irq_pos = 0;
 362         dpcm->period_update_pending = 0;
 363         dpcm->pcm_bps = bps;
 364         dpcm->pcm_salign = salign;
 365         dpcm->pcm_period_size = frames_to_bytes(runtime, runtime->period_size);
 366
 367         mutex_lock(&dpcm->loopback->cable_lock);
 368         if (!(cable->valid & ~(1 << substream->stream)) ||
 369             (get_setup(dpcm)->notify &&
 370              substream->stream == SNDRV_PCM_STREAM_PLAYBACK))
 371                 params_change(substream);
 372         cable->valid |= 1 << substream->stream;
 373         mutex_unlock(&dpcm->loopback->cable_lock);
 374
 375         return 0;
 376 }
 377
 378 static void clear_capture_buf(struct loopback_pcm *dpcm, unsigned int bytes)
 379 {
 380         struct snd_pcm_runtime *runtime = dpcm->substream->runtime;
 381         char *dst = runtime->dma_area;
 382         unsigned int dst_off = dpcm->buf_pos;
 383
 384         if (dpcm->silent_size >= dpcm->pcm_buffer_size)
 385                 return;
 386         if (dpcm->silent_size + bytes > dpcm->pcm_buffer_size)
 387                 bytes = dpcm->pcm_buffer_size - dpcm->silent_size;
 388
 389         for (;;) {
 390                 unsigned int size = bytes;
 391                 if (dst_off + size > dpcm->pcm_buffer_size)
 392                         size = dpcm->pcm_buffer_size - dst_off;
 393                 snd_pcm_format_set_silence(runtime->format, dst + dst_off,
 394                                            bytes_to_frames(runtime, size) *
 395                                                 runtime->channels);
 396                 dpcm->silent_size += size;
 397                 bytes -= size;
 398                 if (!bytes)
 399                         break;
 400                 dst_off = 0;
 401         }
 402 }
 403
 404 static void copy_play_buf(struct loopback_pcm *play,
 405                           struct loopback_pcm *capt,
 406                           unsigned int bytes)
 407 {
 408         struct snd_pcm_runtime *runtime = play->substream->runtime;
 409         char *src = runtime->dma_area;
 410         char *dst = capt->substream->runtime->dma_area;
 411         unsigned int src_off = play->buf_pos;
 412         unsigned int dst_off = capt->buf_pos;
 413         unsigned int clear_bytes = 0;
 414
 415         /* check if playback is draining, trim the capture copy size
 416          * when our pointer is at the end of playback ring buffer */
 417         if (runtime->status->state == SNDRV_PCM_STATE_DRAINING &&
 418             snd_pcm_playback_hw_avail(runtime) < runtime->buffer_size) {
 419                 snd_pcm_uframes_t appl_ptr, appl_ptr1, diff;
 420                 appl_ptr = appl_ptr1 = runtime->control->appl_ptr;
 421                 appl_ptr1 -= appl_ptr1 % runtime->buffer_size;
 422                 appl_ptr1 += play->buf_pos / play->pcm_salign;
 423                 if (appl_ptr < appl_ptr1)
 424                         appl_ptr1 -= runtime->buffer_size;
 425                 diff = (appl_ptr - appl_ptr1) * play->pcm_salign;
 426                 if (diff < bytes) {
 427                         clear_bytes = bytes - diff;
 428                         bytes = diff;
 429                 }
 430         }
 431
 432         for (;;) {
 433                 unsigned int size = bytes;
 434                 if (src_off + size > play->pcm_buffer_size)
 435                         size = play->pcm_buffer_size - src_off;
 436                 if (dst_off + size > capt->pcm_buffer_size)
 437                         size = capt->pcm_buffer_size - dst_off;
 438                 memcpy(dst + dst_off, src + src_off, size);
 439                 capt->silent_size = 0;
 440                 bytes -= size;
 441                 if (!bytes)
 442                         break;
 443                 src_off = (src_off + size) % play->pcm_buffer_size;
 444                 dst_off = (dst_off + size) % capt->pcm_buffer_size;
 445         }
 446
 447         if (clear_bytes > 0) {
 448                 clear_capture_buf(capt, clear_bytes);
 449                 capt->silent_size = 0;
 450         }
 451 }
 452
 453 static inline unsigned int bytepos_delta(struct loopback_pcm *dpcm,
 454                                          unsigned int jiffies_delta)
 455 {
 456         unsigned long last_pos;
 457         unsigned int delta;
 458
 459         last_pos = byte_pos(dpcm, dpcm->irq_pos);
 460         dpcm->irq_pos += jiffies_delta * dpcm->pcm_bps;
 461         delta = byte_pos(dpcm, dpcm->irq_pos) - last_pos;
 462         if (delta >= dpcm->last_drift)
 463                 delta -= dpcm->last_drift;
 464         dpcm->last_drift = 0;
 465         if (dpcm->irq_pos >= dpcm->period_size_frac) {
 466                 dpcm->irq_pos %= dpcm->period_size_frac;
 467                 dpcm->period_update_pending = 1;
 468         }
 469         return delta;
 470 }
 471
 472 static inline void bytepos_finish(struct loopback_pcm *dpcm,
 473                                   unsigned int delta)
 474 {
 475         dpcm->buf_pos += delta;
 476         dpcm->buf_pos %= dpcm->pcm_buffer_size;
 477 }
 478
 479 /* call in cable->lock */
 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
 489         running = cable->running ^ cable->pause;
 490         if (running & (1 << SNDRV_PCM_STREAM_PLAYBACK)) {
 491                 delta_play = jiffies - dpcm_play->last_jiffies;
 492                 dpcm_play->last_jiffies += delta_play;
 493         }
 494
 495         if (running & (1 << SNDRV_PCM_STREAM_CAPTURE)) {
 496                 delta_capt = jiffies - dpcm_capt->last_jiffies;
 497                 dpcm_capt->last_jiffies += delta_capt;
 498         }
 499
 500         if (delta_play == 0 && delta_capt == 0)
 501                 goto unlock;
 502
 503         if (delta_play > delta_capt) {
 504                 count1 = bytepos_delta(dpcm_play, delta_play - delta_capt);
 505                 bytepos_finish(dpcm_play, count1);
 506                 delta_play = delta_capt;
 507         } else if (delta_play < delta_capt) {
 508                 count1 = bytepos_delta(dpcm_capt, delta_capt - delta_play);
 509                 clear_capture_buf(dpcm_capt, count1);
 510                 bytepos_finish(dpcm_capt, count1);
 511                 delta_capt = delta_play;
 512         }
 513
 514         if (delta_play == 0 && delta_capt == 0)
 515                 goto unlock;
 516
 517         /* note delta_capt == delta_play at this moment */
 518         count1 = bytepos_delta(dpcm_play, delta_play);
 519         count2 = bytepos_delta(dpcm_capt, delta_capt);
 520         if (count1 < count2) {
 521                 dpcm_capt->last_drift = count2 - count1;
 522                 count1 = count2;
 523         } else if (count1 > count2) {
 524                 dpcm_play->last_drift = count1 - count2;
 525         }
 526         copy_play_buf(dpcm_play, dpcm_capt, count1);
 527         bytepos_finish(dpcm_play, count1);
 528         bytepos_finish(dpcm_capt, count1);
 529  unlock:
 530         return running;
 531 }
 532
 533 static void loopback_timer_function(unsigned long data)
 534 {
 535         struct loopback_pcm *dpcm = (struct loopback_pcm *)data;
 536         unsigned long flags;
 537
 538         spin_lock_irqsave(&dpcm->cable->lock, flags);
 539         if (loopback_pos_update(dpcm->cable) & (1 << dpcm->substream->stream)) {
 540                 loopback_timer_start(dpcm);
 541                 if (dpcm->period_update_pending) {
 542                         dpcm->period_update_pending = 0;
 543                         spin_unlock_irqrestore(&dpcm->cable->lock, flags);
 544                         /* need to unlock before calling below */
 545                         snd_pcm_period_elapsed(dpcm->substream);
 546                         return;
 547                 }
 548         }
 549         spin_unlock_irqrestore(&dpcm->cable->lock, flags);
 550 }
 551
 552 static snd_pcm_uframes_t loopback_pointer(struct snd_pcm_substream *substream)
 553 {
 554         struct snd_pcm_runtime *runtime = substream->runtime;
 555         struct loopback_pcm *dpcm = runtime->private_data;
 556         snd_pcm_uframes_t pos;
 557
 558         spin_lock(&dpcm->cable->lock);
 559         loopback_pos_update(dpcm->cable);
 560         pos = dpcm->buf_pos;
 561         spin_unlock(&dpcm->cable->lock);
 562         return bytes_to_frames(runtime, pos);
 563 }
 564
 565 static struct snd_pcm_hardware loopback_pcm_hardware =
 566 {
 567         .info =         (SNDRV_PCM_INFO_INTERLEAVED | SNDRV_PCM_INFO_MMAP |
 568                          SNDRV_PCM_INFO_MMAP_VALID | SNDRV_PCM_INFO_PAUSE |
 569                          SNDRV_PCM_INFO_RESUME),
 570         .formats =      (SNDRV_PCM_FMTBIT_S16_LE | SNDRV_PCM_FMTBIT_S16_BE |
 571                          SNDRV_PCM_FMTBIT_S32_LE | SNDRV_PCM_FMTBIT_S32_BE |
 572                          SNDRV_PCM_FMTBIT_FLOAT_LE | SNDRV_PCM_FMTBIT_FLOAT_BE),
 573         .rates =        SNDRV_PCM_RATE_CONTINUOUS | SNDRV_PCM_RATE_8000_192000,
 574         .rate_min =             8000,
 575         .rate_max =             192000,
 576         .channels_min =         1,
 577         .channels_max =         32,
 578         .buffer_bytes_max =     2 * 1024 * 1024,
 579         .period_bytes_min =     64,
 580         /* note check overflow in frac_pos() using pcm_rate_shift before
 581            changing period_bytes_max value */
 582         .period_bytes_max =     1024 * 1024,
 583         .periods_min =          1,
 584         .periods_max =          1024,
 585         .fifo_size =            0,
 586 };
 587
 588 static void loopback_runtime_free(struct snd_pcm_runtime *runtime)
 589 {
 590         struct loopback_pcm *dpcm = runtime->private_data;
 591         kfree(dpcm);
 592 }
 593
 594 static int loopback_hw_params(struct snd_pcm_substream *substream,
 595                               struct snd_pcm_hw_params *params)
 596 {
 597         return snd_pcm_lib_alloc_vmalloc_buffer(substream,
 598                                                 params_buffer_bytes(params));
 599 }
 600
 601 static int loopback_hw_free(struct snd_pcm_substream *substream)
 602 {
 603         struct snd_pcm_runtime *runtime = substream->runtime;
 604         struct loopback_pcm *dpcm = runtime->private_data;
 605         struct loopback_cable *cable = dpcm->cable;
 606
 607         mutex_lock(&dpcm->loopback->cable_lock);
 608         cable->valid &= ~(1 << substream->stream);
 609         mutex_unlock(&dpcm->loopback->cable_lock);
 610         return snd_pcm_lib_free_vmalloc_buffer(substream);
 611 }
 612
 613 static unsigned int get_cable_index(struct snd_pcm_substream *substream)
 614 {
 615         if (!substream->pcm->device)
 616                 return substream->stream;
 617         else
 618                 return !substream->stream;
 619 }
 620
 621 static int rule_format(struct snd_pcm_hw_params *params,
 622                        struct snd_pcm_hw_rule *rule)
 623 {
 624
 625         struct snd_pcm_hardware *hw = rule->private;
 626         struct snd_mask *maskp = hw_param_mask(params, rule->var);
 627
 628         maskp->bits[0] &= (u_int32_t)hw->formats;
 629         maskp->bits[1] &= (u_int32_t)(hw->formats >> 32);
 630         memset(maskp->bits + 2, 0, (SNDRV_MASK_MAX-64) / 8); /* clear rest */
 631         if (! maskp->bits[0] && ! maskp->bits[1])
 632                 return -EINVAL;
 633         return 0;
 634 }
 635
 636 static int rule_rate(struct snd_pcm_hw_params *params,
 637                      struct snd_pcm_hw_rule *rule)
 638 {
 639         struct snd_pcm_hardware *hw = rule->private;
 640         struct snd_interval t;
 641
 642         t.min = hw->rate_min;
 643         t.max = hw->rate_max;
 644         t.openmin = t.openmax = 0;
 645         t.integer = 0;
 646         return snd_interval_refine(hw_param_interval(params, rule->var), &t);
 647 }
 648
 649 static int rule_channels(struct snd_pcm_hw_params *params,
 650                          struct snd_pcm_hw_rule *rule)
 651 {
 652         struct snd_pcm_hardware *hw = rule->private;
 653         struct snd_interval t;
 654
 655         t.min = hw->channels_min;
 656         t.max = hw->channels_max;
 657         t.openmin = t.openmax = 0;
 658         t.integer = 0;
 659         return snd_interval_refine(hw_param_interval(params, rule->var), &t);
 660 }
 661
 662 static int loopback_open(struct snd_pcm_substream *substream)
 663 {
 664         struct snd_pcm_runtime *runtime = substream->runtime;
 665         struct loopback *loopback = substream->private_data;
 666         struct loopback_pcm *dpcm;
 667         struct loopback_cable *cable;
 668         int err = 0;
 669         int dev = get_cable_index(substream);
 670
 671         mutex_lock(&loopback->cable_lock);
 672         dpcm = kzalloc(sizeof(*dpcm), GFP_KERNEL);
 673         if (!dpcm) {
 674                 err = -ENOMEM;
 675                 goto unlock;
 676         }
 677         dpcm->loopback = loopback;
 678         dpcm->substream = substream;
 679         setup_timer(&dpcm->timer, loopback_timer_function,
 680                     (unsigned long)dpcm);
 681
 682         cable = loopback->cables[substream->number][dev];
 683         if (!cable) {
 684                 cable = kzalloc(sizeof(*cable), GFP_KERNEL);
 685                 if (!cable) {
 686                         kfree(dpcm);
 687                         err = -ENOMEM;
 688                         goto unlock;
 689                 }
 690                 spin_lock_init(&cable->lock);
 691                 cable->hw = loopback_pcm_hardware;
 692                 loopback->cables[substream->number][dev] = cable;
 693         }
 694         dpcm->cable = cable;
 695         cable->streams[substream->stream] = dpcm;
 696
 697         snd_pcm_hw_constraint_integer(runtime, SNDRV_PCM_HW_PARAM_PERIODS);
 698
 699         /* use dynamic rules based on actual runtime->hw values */
 700         /* note that the default rules created in the PCM midlevel code */
 701         /* are cached -> they do not reflect the actual state */
 702         err = snd_pcm_hw_rule_add(runtime, 0,
 703                                   SNDRV_PCM_HW_PARAM_FORMAT,
 704                                   rule_format, &runtime->hw,
 705                                   SNDRV_PCM_HW_PARAM_FORMAT, -1);
 706         if (err < 0)
 707                 goto unlock;
 708         err = snd_pcm_hw_rule_add(runtime, 0,
 709                                   SNDRV_PCM_HW_PARAM_RATE,
 710                                   rule_rate, &runtime->hw,
 711                                   SNDRV_PCM_HW_PARAM_RATE, -1);
 712         if (err < 0)
 713                 goto unlock;
 714         err = snd_pcm_hw_rule_add(runtime, 0,
 715                                   SNDRV_PCM_HW_PARAM_CHANNELS,
 716                                   rule_channels, &runtime->hw,
 717                                   SNDRV_PCM_HW_PARAM_CHANNELS, -1);
 718         if (err < 0)
 719                 goto unlock;
 720
 721         runtime->private_data = dpcm;
 722         runtime->private_free = loopback_runtime_free;
 723         if (get_notify(dpcm))
 724                 runtime->hw = loopback_pcm_hardware;
 725         else
 726                 runtime->hw = cable->hw;
 727  unlock:
 728         mutex_unlock(&loopback->cable_lock);
 729         return err;
 730 }
 731
 732 static int loopback_close(struct snd_pcm_substream *substream)
 733 {
 734         struct loopback *loopback = substream->private_data;
 735         struct loopback_pcm *dpcm = substream->runtime->private_data;
 736         struct loopback_cable *cable;
 737         int dev = get_cable_index(substream);
 738
 739         loopback_timer_stop(dpcm);
 740         mutex_lock(&loopback->cable_lock);
 741         cable = loopback->cables[substream->number][dev];
 742         if (cable->streams[!substream->stream]) {
 743                 /* other stream is still alive */
 744                 cable->streams[substream->stream] = NULL;
 745         } else {
 746                 /* free the cable */
 747                 loopback->cables[substream->number][dev] = NULL;
 748                 kfree(cable);
 749         }
 750         mutex_unlock(&loopback->cable_lock);
 751         return 0;
 752 }
 753
 754 static struct snd_pcm_ops loopback_playback_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 struct snd_pcm_ops loopback_capture_ops = {
 768         .open =         loopback_open,
 769         .close =        loopback_close,
 770         .ioctl =        snd_pcm_lib_ioctl,
 771         .hw_params =    loopback_hw_params,
 772         .hw_free =      loopback_hw_free,
 773         .prepare =      loopback_prepare,
 774         .trigger =      loopback_trigger,
 775         .pointer =      loopback_pointer,
 776         .page =         snd_pcm_lib_get_vmalloc_page,
 777         .mmap =         snd_pcm_lib_mmap_vmalloc,
 778 };
 779
 780 static int loopback_pcm_new(struct loopback *loopback,
 781                             int device, int substreams)
 782 {
 783         struct snd_pcm *pcm;
 784         int err;
 785
 786         err = snd_pcm_new(loopback->card, "Loopback PCM", device,
 787                           substreams, substreams, &pcm);
 788         if (err < 0)
 789                 return err;
 790         snd_pcm_set_ops(pcm, SNDRV_PCM_STREAM_PLAYBACK, &loopback_playback_ops);
 791         snd_pcm_set_ops(pcm, SNDRV_PCM_STREAM_CAPTURE, &loopback_capture_ops);
 792
 793         pcm->private_data = loopback;
 794         pcm->info_flags = 0;
 795         strcpy(pcm->name, "Loopback PCM");
 796
 797         loopback->pcm[device] = pcm;
 798         return 0;
 799 }
 800
 801 static int loopback_rate_shift_info(struct snd_kcontrol *kcontrol,
 802                                     struct snd_ctl_elem_info *uinfo)
 803 {
 804         uinfo->type = SNDRV_CTL_ELEM_TYPE_INTEGER;
 805         uinfo->count = 1;
 806         uinfo->value.integer.min = 80000;
 807         uinfo->value.integer.max = 120000;
 808         uinfo->value.integer.step = 1;
 809         return 0;
 810 }
 811
 812 static int loopback_rate_shift_get(struct snd_kcontrol *kcontrol,
 813                                    struct snd_ctl_elem_value *ucontrol)
 814 {
 815         struct loopback *loopback = snd_kcontrol_chip(kcontrol);
 816
 817         ucontrol->value.integer.value[0] =
 818                 loopback->setup[kcontrol->id.subdevice]
 819                                [kcontrol->id.device].rate_shift;
 820         return 0;
 821 }
 822
 823 static int loopback_rate_shift_put(struct snd_kcontrol *kcontrol,
 824                                    struct snd_ctl_elem_value *ucontrol)
 825 {
 826         struct loopback *loopback = snd_kcontrol_chip(kcontrol);
 827         unsigned int val;
 828         int change = 0;
 829
 830         val = ucontrol->value.integer.value[0];
 831         if (val < 80000)
 832                 val = 80000;
 833         if (val > 120000)
 834                 val = 120000;
 835         mutex_lock(&loopback->cable_lock);
 836         if (val != loopback->setup[kcontrol->id.subdevice]
 837                                   [kcontrol->id.device].rate_shift) {
 838                 loopback->setup[kcontrol->id.subdevice]
 839                                [kcontrol->id.device].rate_shift = val;
 840                 change = 1;
 841         }
 842         mutex_unlock(&loopback->cable_lock);
 843         return change;
 844 }
 845
 846 static int loopback_notify_get(struct snd_kcontrol *kcontrol,
 847                                struct snd_ctl_elem_value *ucontrol)
 848 {
 849         struct loopback *loopback = snd_kcontrol_chip(kcontrol);
 850
 851         ucontrol->value.integer.value[0] =
 852                 loopback->setup[kcontrol->id.subdevice]
 853                                [kcontrol->id.device].notify;
 854         return 0;
 855 }
 856
 857 static int loopback_notify_put(struct snd_kcontrol *kcontrol,
 858                                struct snd_ctl_elem_value *ucontrol)
 859 {
 860         struct loopback *loopback = snd_kcontrol_chip(kcontrol);
 861         unsigned int val;
 862         int change = 0;
 863
 864         val = ucontrol->value.integer.value[0] ? 1 : 0;
 865         if (val != loopback->setup[kcontrol->id.subdevice]
 866                                 [kcontrol->id.device].notify) {
 867                 loopback->setup[kcontrol->id.subdevice]
 868                         [kcontrol->id.device].notify = val;
 869                 change = 1;
 870         }
 871         return change;
 872 }
 873
 874 static int loopback_active_get(struct snd_kcontrol *kcontrol,
 875                                struct snd_ctl_elem_value *ucontrol)
 876 {
 877         struct loopback *loopback = snd_kcontrol_chip(kcontrol);
 878         struct loopback_cable *cable = loopback->cables
 879                         [kcontrol->id.subdevice][kcontrol->id.device ^ 1];
 880         unsigned int val = 0;
 881
 882         if (cable != NULL)
 883                 val = (cable->running & (1 << SNDRV_PCM_STREAM_PLAYBACK)) ?
 884                                                                         1 : 0;
 885         ucontrol->value.integer.value[0] = val;
 886         return 0;
 887 }
 888
 889 static int loopback_format_info(struct snd_kcontrol *kcontrol,
 890                                 struct snd_ctl_elem_info *uinfo)
 891 {
 892         uinfo->type = SNDRV_CTL_ELEM_TYPE_INTEGER;
 893         uinfo->count = 1;
 894         uinfo->value.integer.min = 0;
 895         uinfo->value.integer.max = SNDRV_PCM_FORMAT_LAST;
 896         uinfo->value.integer.step = 1;
 897         return 0;
 898 }
 899
 900 static int loopback_format_get(struct snd_kcontrol *kcontrol,
 901                                struct snd_ctl_elem_value *ucontrol)
 902 {
 903         struct loopback *loopback = snd_kcontrol_chip(kcontrol);
 904
 905         ucontrol->value.integer.value[0] =
 906                 loopback->setup[kcontrol->id.subdevice]
 907                                [kcontrol->id.device].format;
 908         return 0;
 909 }
 910
 911 static int loopback_rate_info(struct snd_kcontrol *kcontrol,
 912                               struct snd_ctl_elem_info *uinfo)
 913 {
 914         uinfo->type = SNDRV_CTL_ELEM_TYPE_INTEGER;
 915         uinfo->count = 1;
 916         uinfo->value.integer.min = 0;
 917         uinfo->value.integer.max = 192000;
 918         uinfo->value.integer.step = 1;
 919         return 0;
 920 }
 921
 922 static int loopback_rate_get(struct snd_kcontrol *kcontrol,
 923                              struct snd_ctl_elem_value *ucontrol)
 924 {
 925         struct loopback *loopback = snd_kcontrol_chip(kcontrol);
 926
 927         ucontrol->value.integer.value[0] =
 928                 loopback->setup[kcontrol->id.subdevice]
 929                                [kcontrol->id.device].rate;
 930         return 0;
 931 }
 932
 933 static int loopback_channels_info(struct snd_kcontrol *kcontrol,
 934                                   struct snd_ctl_elem_info *uinfo)
 935 {
 936         uinfo->type = SNDRV_CTL_ELEM_TYPE_INTEGER;
 937         uinfo->count = 1;
 938         uinfo->value.integer.min = 1;
 939         uinfo->value.integer.max = 1024;
 940         uinfo->value.integer.step = 1;
 941         return 0;
 942 }
 943
 944 static int loopback_channels_get(struct snd_kcontrol *kcontrol,
 945                                  struct snd_ctl_elem_value *ucontrol)
 946 {
 947         struct loopback *loopback = snd_kcontrol_chip(kcontrol);
 948
 949         ucontrol->value.integer.value[0] =
 950                 loopback->setup[kcontrol->id.subdevice]
 951                                [kcontrol->id.device].channels;
 952         return 0;
 953 }
 954
 955 static struct snd_kcontrol_new loopback_controls[]  = {
 956 {
 957         .iface =        SNDRV_CTL_ELEM_IFACE_PCM,
 958         .name =         "PCM Rate Shift 100000",
 959         .info =         loopback_rate_shift_info,
 960         .get =          loopback_rate_shift_get,
 961         .put =          loopback_rate_shift_put,
 962 },
 963 {
 964         .iface =        SNDRV_CTL_ELEM_IFACE_PCM,
 965         .name =         "PCM Notify",
 966         .info =         snd_ctl_boolean_mono_info,
 967         .get =          loopback_notify_get,
 968         .put =          loopback_notify_put,
 969 },
 970 #define ACTIVE_IDX 2
 971 {
 972         .access =       SNDRV_CTL_ELEM_ACCESS_READ,
 973         .iface =        SNDRV_CTL_ELEM_IFACE_PCM,
 974         .name =         "PCM Slave Active",
 975         .info =         snd_ctl_boolean_mono_info,
 976         .get =          loopback_active_get,
 977 },
 978 #define FORMAT_IDX 3
 979 {
 980         .access =       SNDRV_CTL_ELEM_ACCESS_READ,
 981         .iface =        SNDRV_CTL_ELEM_IFACE_PCM,
 982         .name =         "PCM Slave Format",
 983         .info =         loopback_format_info,
 984         .get =          loopback_format_get
 985 },
 986 #define RATE_IDX 4
 987 {
 988         .access =       SNDRV_CTL_ELEM_ACCESS_READ,
 989         .iface =        SNDRV_CTL_ELEM_IFACE_PCM,
 990         .name =         "PCM Slave Rate",
 991         .info =         loopback_rate_info,
 992         .get =          loopback_rate_get
 993 },
 994 #define CHANNELS_IDX 5
 995 {
 996         .access =       SNDRV_CTL_ELEM_ACCESS_READ,
 997         .iface =        SNDRV_CTL_ELEM_IFACE_PCM,
 998         .name =         "PCM Slave Channels",
 999         .info =         loopback_channels_info,
1000         .get =          loopback_channels_get
1001 }
1002 };
1003
1004 static int loopback_mixer_new(struct loopback *loopback, int notify)
1005 {
1006         struct snd_card *card = loopback->card;
1007         struct snd_pcm *pcm;
1008         struct snd_kcontrol *kctl;
1009         struct loopback_setup *setup;
1010         int err, dev, substr, substr_count, idx;
1011
1012         strcpy(card->mixername, "Loopback Mixer");
1013         for (dev = 0; dev < 2; dev++) {
1014                 pcm = loopback->pcm[dev];
1015                 substr_count =
1016                     pcm->streams[SNDRV_PCM_STREAM_CAPTURE].substream_count;
1017                 for (substr = 0; substr < substr_count; substr++) {
1018                         setup = &loopback->setup[substr][dev];
1019                         setup->notify = notify;
1020                         setup->rate_shift = NO_PITCH;
1021                         setup->format = SNDRV_PCM_FORMAT_S16_LE;
1022                         setup->rate = 48000;
1023                         setup->channels = 2;
1024                         for (idx = 0; idx < ARRAY_SIZE(loopback_controls);
1025                                                                         idx++) {
1026                                 kctl = snd_ctl_new1(&loopback_controls[idx],
1027                                                     loopback);
1028                                 if (!kctl)
1029                                         return -ENOMEM;
1030                                 kctl->id.device = dev;
1031                                 kctl->id.subdevice = substr;
1032                                 switch (idx) {
1033                                 case ACTIVE_IDX:
1034                                         setup->active_id = kctl->id;
1035                                         break;
1036                                 case FORMAT_IDX:
1037                                         setup->format_id = kctl->id;
1038                                         break;
1039                                 case RATE_IDX:
1040                                         setup->rate_id = kctl->id;
1041                                         break;
1042                                 case CHANNELS_IDX:
1043                                         setup->channels_id = kctl->id;
1044                                         break;
1045                                 default:
1046                                         break;
1047                                 }
1048                                 err = snd_ctl_add(card, kctl);
1049                                 if (err < 0)
1050                                         return err;
1051                         }
1052                 }
1053         }
1054         return 0;
1055 }
1056
1057 #ifdef CONFIG_PROC_FS
1058
1059 static void print_dpcm_info(struct snd_info_buffer *buffer,
1060                             struct loopback_pcm *dpcm,
1061                             const char *id)
1062 {
1063         snd_iprintf(buffer, "  %s\n", id);
1064         if (dpcm == NULL) {
1065                 snd_iprintf(buffer, "    inactive\n");
1066                 return;
1067         }
1068         snd_iprintf(buffer, "    buffer_size:\t%u\n", dpcm->pcm_buffer_size);
1069         snd_iprintf(buffer, "    buffer_pos:\t\t%u\n", dpcm->buf_pos);
1070         snd_iprintf(buffer, "    silent_size:\t%u\n", dpcm->silent_size);
1071         snd_iprintf(buffer, "    period_size:\t%u\n", dpcm->pcm_period_size);
1072         snd_iprintf(buffer, "    bytes_per_sec:\t%u\n", dpcm->pcm_bps);
1073         snd_iprintf(buffer, "    sample_align:\t%u\n", dpcm->pcm_salign);
1074         snd_iprintf(buffer, "    rate_shift:\t\t%u\n", dpcm->pcm_rate_shift);
1075         snd_iprintf(buffer, "    update_pending:\t%u\n",
1076                                                 dpcm->period_update_pending);
1077         snd_iprintf(buffer, "    irq_pos:\t\t%u\n", dpcm->irq_pos);
1078         snd_iprintf(buffer, "    period_frac:\t%u\n", dpcm->period_size_frac);
1079         snd_iprintf(buffer, "    last_jiffies:\t%lu (%lu)\n",
1080                                         dpcm->last_jiffies, jiffies);
1081         snd_iprintf(buffer, "    timer_expires:\t%lu\n", dpcm->timer.expires);
1082 }
1083
1084 static void print_substream_info(struct snd_info_buffer *buffer,
1085                                  struct loopback *loopback,
1086                                  int sub,
1087                                  int num)
1088 {
1089         struct loopback_cable *cable = loopback->cables[sub][num];
1090
1091         snd_iprintf(buffer, "Cable %i substream %i:\n", num, sub);
1092         if (cable == NULL) {
1093                 snd_iprintf(buffer, "  inactive\n");
1094                 return;
1095         }
1096         snd_iprintf(buffer, "  valid: %u\n", cable->valid);
1097         snd_iprintf(buffer, "  running: %u\n", cable->running);
1098         snd_iprintf(buffer, "  pause: %u\n", cable->pause);
1099         print_dpcm_info(buffer, cable->streams[0], "Playback");
1100         print_dpcm_info(buffer, cable->streams[1], "Capture");
1101 }
1102
1103 static void print_cable_info(struct snd_info_entry *entry,
1104                              struct snd_info_buffer *buffer)
1105 {
1106         struct loopback *loopback = entry->private_data;
1107         int sub, num;
1108
1109         mutex_lock(&loopback->cable_lock);
1110         num = entry->name[strlen(entry->name)-1];
1111         num = num == '0' ? 0 : 1;
1112         for (sub = 0; sub < MAX_PCM_SUBSTREAMS; sub++)
1113                 print_substream_info(buffer, loopback, sub, num);
1114         mutex_unlock(&loopback->cable_lock);
1115 }
1116
1117 static int loopback_proc_new(struct loopback *loopback, int cidx)
1118 {
1119         char name[32];
1120         struct snd_info_entry *entry;
1121         int err;
1122
1123         snprintf(name, sizeof(name), "cable#%d", cidx);
1124         err = snd_card_proc_new(loopback->card, name, &entry);
1125         if (err < 0)
1126                 return err;
1127
1128         snd_info_set_text_ops(entry, loopback, print_cable_info);
1129         return 0;
1130 }
1131
1132 #else /* !CONFIG_PROC_FS */
1133
1134 #define loopback_proc_new(loopback, cidx) do { } while (0)
1135
1136 #endif
1137
1138 static int loopback_probe(struct platform_device *devptr)
1139 {
1140         struct snd_card *card;
1141         struct loopback *loopback;
1142         int dev = devptr->id;
1143         int err;
1144
1145         err = snd_card_new(&devptr->dev, index[dev], id[dev], THIS_MODULE,
1146                            sizeof(struct loopback), &card);
1147         if (err < 0)
1148                 return err;
1149         loopback = card->private_data;
1150
1151         if (pcm_substreams[dev] < 1)
1152                 pcm_substreams[dev] = 1;
1153         if (pcm_substreams[dev] > MAX_PCM_SUBSTREAMS)
1154                 pcm_substreams[dev] = MAX_PCM_SUBSTREAMS;
1155
1156         loopback->card = card;
1157         mutex_init(&loopback->cable_lock);
1158
1159         err = loopback_pcm_new(loopback, 0, pcm_substreams[dev]);
1160         if (err < 0)
1161                 goto __nodev;
1162         err = loopback_pcm_new(loopback, 1, pcm_substreams[dev]);
1163         if (err < 0)
1164                 goto __nodev;
1165         err = loopback_mixer_new(loopback, pcm_notify[dev] ? 1 : 0);
1166         if (err < 0)
1167                 goto __nodev;
1168         loopback_proc_new(loopback, 0);
1169         loopback_proc_new(loopback, 1);
1170         strcpy(card->driver, "Loopback");
1171         strcpy(card->shortname, "Loopback");
1172         sprintf(card->longname, "Loopback %i", dev + 1);
1173         err = snd_card_register(card);
1174         if (!err) {
1175                 platform_set_drvdata(devptr, card);
1176                 return 0;
1177         }
1178       __nodev:
1179         snd_card_free(card);
1180         return err;
1181 }
1182
1183 static int loopback_remove(struct platform_device *devptr)
1184 {
1185         snd_card_free(platform_get_drvdata(devptr));
1186         return 0;
1187 }
1188
1189 #ifdef CONFIG_PM_SLEEP
1190 static int loopback_suspend(struct device *pdev)
1191 {
1192         struct snd_card *card = dev_get_drvdata(pdev);
1193         struct loopback *loopback = card->private_data;
1194
1195         snd_power_change_state(card, SNDRV_CTL_POWER_D3hot);
1196
1197         snd_pcm_suspend_all(loopback->pcm[0]);
1198         snd_pcm_suspend_all(loopback->pcm[1]);
1199         return 0;
1200 }
1201
1202 static int loopback_resume(struct device *pdev)
1203 {
1204         struct snd_card *card = dev_get_drvdata(pdev);
1205
1206         snd_power_change_state(card, SNDRV_CTL_POWER_D0);
1207         return 0;
1208 }
1209
1210 static SIMPLE_DEV_PM_OPS(loopback_pm, loopback_suspend, loopback_resume);
1211 #define LOOPBACK_PM_OPS &loopback_pm
1212 #else
1213 #define LOOPBACK_PM_OPS NULL
1214 #endif
1215
1216 #define SND_LOOPBACK_DRIVER     "snd_aloop"
1217
1218 static struct platform_driver loopback_driver = {
1219         .probe          = loopback_probe,
1220         .remove         = loopback_remove,
1221         .driver         = {
1222                 .name   = SND_LOOPBACK_DRIVER,
1223                 .pm     = LOOPBACK_PM_OPS,
1224         },
1225 };
1226
1227 static void loopback_unregister_all(void)
1228 {
1229         int i;
1230
1231         for (i = 0; i < ARRAY_SIZE(devices); ++i)
1232                 platform_device_unregister(devices[i]);
1233         platform_driver_unregister(&loopback_driver);
1234 }
1235
1236 static int __init alsa_card_loopback_init(void)
1237 {
1238         int i, err, cards;
1239
1240         err = platform_driver_register(&loopback_driver);
1241         if (err < 0)
1242                 return err;
1243
1244
1245         cards = 0;
1246         for (i = 0; i < SNDRV_CARDS; i++) {
1247                 struct platform_device *device;
1248                 if (!enable[i])
1249                         continue;
1250                 device = platform_device_register_simple(SND_LOOPBACK_DRIVER,
1251                                                          i, NULL, 0);
1252                 if (IS_ERR(device))
1253                         continue;
1254                 if (!platform_get_drvdata(device)) {
1255                         platform_device_unregister(device);
1256                         continue;
1257                 }
1258                 devices[i] = device;
1259                 cards++;
1260         }
1261         if (!cards) {
1262 #ifdef MODULE
1263                 printk(KERN_ERR "aloop: No loopback enabled\n");
1264 #endif
1265                 loopback_unregister_all();
1266                 return -ENODEV;
1267         }
1268         return 0;
1269 }
1270
1271 static void __exit alsa_card_loopback_exit(void)
1272 {
1273         loopback_unregister_all();
1274 }
1275
1276 module_init(alsa_card_loopback_init)
1277 module_exit(alsa_card_loopback_exit)