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