sound/drivers/aloop.c

   1 // SPDX-License-Identifier: GPL-2.0-or-later
   2 /*
   3  *  Loopback soundcard
   4  *
   5  *  Original code:
   6  *  Copyright (c) by Jaroslav Kysela <perex@perex.cz>
   7  *
   8  *  More accurate positioning and full-duplex support:
   9  *  Copyright (c) Ahmet İnan <ainan at mathematik.uni-freiburg.de>
  10  *
  11  *  Major (almost complete) rewrite:
  12  *  Copyright (c) by Takashi Iwai <tiwai@suse.de>
  13  *
  14  *  A next major update in 2010 (separate timers for playback and capture):
  15  *  Copyright (c) Jaroslav Kysela <perex@perex.cz>
  16  */
  17
  18 #include <linux/init.h>
  19 #include <linux/jiffies.h>
  20 #include <linux/slab.h>
  21 #include <linux/time.h>
  22 #include <linux/wait.h>
  23 #include <linux/module.h>
  24 #include <linux/platform_device.h>
  25 #include <sound/core.h>
  26 #include <sound/control.h>
  27 #include <sound/pcm.h>
  28 #include <sound/pcm_params.h>
  29 #include <sound/info.h>
  30 #include <sound/initval.h>
  31
  32 MODULE_AUTHOR("Jaroslav Kysela <perex@perex.cz>");
  33 MODULE_DESCRIPTION("A loopback soundcard");
  34 MODULE_LICENSE("GPL");
  35 MODULE_SUPPORTED_DEVICE("{{ALSA,Loopback soundcard}}");
  36
  37 #define MAX_PCM_SUBSTREAMS      8
  38
  39 static int index[SNDRV_CARDS] = SNDRV_DEFAULT_IDX;      /* Index 0-MAX */
  40 static char *id[SNDRV_CARDS] = SNDRV_DEFAULT_STR;       /* ID for this card */
  41 static bool enable[SNDRV_CARDS] = {1, [1 ... (SNDRV_CARDS - 1)] = 0};
  42 static int pcm_substreams[SNDRV_CARDS] = {[0 ... (SNDRV_CARDS - 1)] = 8};
  43 static int pcm_notify[SNDRV_CARDS];
  44
  45 module_param_array(index, int, NULL, 0444);
  46 MODULE_PARM_DESC(index, "Index value for loopback soundcard.");
  47 module_param_array(id, charp, NULL, 0444);
  48 MODULE_PARM_DESC(id, "ID string for loopback soundcard.");
  49 module_param_array(enable, bool, NULL, 0444);
  50 MODULE_PARM_DESC(enable, "Enable this loopback soundcard.");
  51 module_param_array(pcm_substreams, int, NULL, 0444);
  52 MODULE_PARM_DESC(pcm_substreams, "PCM substreams # (1-8) for loopback driver.");
  53 module_param_array(pcm_notify, int, NULL, 0444);
  54 MODULE_PARM_DESC(pcm_notify, "Break capture when PCM format/rate/channels changes.");
  55
  56 #define NO_PITCH 100000
  57
  58 struct loopback_pcm;
  59
  60 struct loopback_cable {
  61         spinlock_t lock;
  62         struct loopback_pcm *streams[2];
  63         struct snd_pcm_hardware hw;
  64         /* flags */
  65         unsigned int valid;
  66         unsigned int running;
  67         unsigned int pause;
  68 };
  69
  70 struct loopback_setup {
  71         unsigned int notify: 1;
  72         unsigned int rate_shift;
  73         unsigned int format;
  74         unsigned int rate;
  75         unsigned int channels;
  76         struct snd_ctl_elem_id active_id;
  77         struct snd_ctl_elem_id format_id;
  78         struct snd_ctl_elem_id rate_id;
  79         struct snd_ctl_elem_id channels_id;
  80 };
  81
  82 struct loopback {
  83         struct snd_card *card;
  84         struct mutex cable_lock;
  85         struct loopback_cable *cables[MAX_PCM_SUBSTREAMS][2];
  86         struct snd_pcm *pcm[2];
  87         struct loopback_setup setup[MAX_PCM_SUBSTREAMS][2];
  88 };
  89
  90 struct loopback_pcm {
  91         struct loopback *loopback;
  92         struct snd_pcm_substream *substream;
  93         struct loopback_cable *cable;
  94         unsigned int pcm_buffer_size;
  95         unsigned int buf_pos;   /* position in buffer */
  96         unsigned int silent_size;
  97         /* PCM parameters */
  98         unsigned int pcm_period_size;
  99         unsigned int pcm_bps;           /* bytes per second */
 100         unsigned int pcm_salign;        /* bytes per sample * channels */
 101         unsigned int pcm_rate_shift;    /* rate shift value */
 102         /* flags */
 103         unsigned int period_update_pending :1;
 104         /* timer stuff */
 105         unsigned int irq_pos;           /* fractional IRQ position */
 106         unsigned int period_size_frac;
 107         unsigned int last_drift;
 108         unsigned long last_jiffies;
 109         struct timer_list timer;
 110 };
 111
 112 static struct platform_device *devices[SNDRV_CARDS];
 113
 114 static inline unsigned int byte_pos(struct loopback_pcm *dpcm, unsigned int x)
 115 {
 116         if (dpcm->pcm_rate_shift == NO_PITCH) {
 117                 x /= HZ;
 118         } else {
 119                 x = div_u64(NO_PITCH * (unsigned long long)x,
 120                             HZ * (unsigned long long)dpcm->pcm_rate_shift);
 121         }
 122         return x - (x % dpcm->pcm_salign);
 123 }
 124
 125 static inline unsigned int frac_pos(struct loopback_pcm *dpcm, unsigned int x)
 126 {
 127         if (dpcm->pcm_rate_shift == NO_PITCH) { /* no pitch */
 128                 return x * HZ;
 129         } else {
 130                 x = div_u64(dpcm->pcm_rate_shift * (unsigned long long)x * HZ,
 131                             NO_PITCH);
 132         }
 133         return x;
 134 }
 135
 136 static inline struct loopback_setup *get_setup(struct loopback_pcm *dpcm)
 137 {
 138         int device = dpcm->substream->pstr->pcm->device;
 139
 140         if (dpcm->substream->stream == SNDRV_PCM_STREAM_PLAYBACK)
 141                 device ^= 1;
 142         return &dpcm->loopback->setup[dpcm->substream->number][device];
 143 }
 144
 145 static inline unsigned int get_notify(struct loopback_pcm *dpcm)
 146 {
 147         return get_setup(dpcm)->notify;
 148 }
 149
 150 static inline unsigned int get_rate_shift(struct loopback_pcm *dpcm)
 151 {
 152         return get_setup(dpcm)->rate_shift;
 153 }
 154
 155 /* call in cable->lock */
 156 static void loopback_timer_start(struct loopback_pcm *dpcm)
 157 {
 158         unsigned long tick;
 159         unsigned int rate_shift = get_rate_shift(dpcm);
 160
 161         if (rate_shift != dpcm->pcm_rate_shift) {
 162                 dpcm->pcm_rate_shift = rate_shift;
 163                 dpcm->period_size_frac = frac_pos(dpcm, dpcm->pcm_period_size);
 164         }
 165         if (dpcm->period_size_frac <= dpcm->irq_pos) {
 166                 dpcm->irq_pos %= dpcm->period_size_frac;
 167                 dpcm->period_update_pending = 1;
 168         }
 169         tick = dpcm->period_size_frac - dpcm->irq_pos;
 170         tick = (tick + dpcm->pcm_bps - 1) / dpcm->pcm_bps;
 171         mod_timer(&dpcm->timer, jiffies + tick);
 172 }
 173
 174 /* call in cable->lock */
 175 static inline void loopback_timer_stop(struct loopback_pcm *dpcm)
 176 {
 177         del_timer(&dpcm->timer);
 178         dpcm->timer.expires = 0;
 179 }
 180
 181 static inline void loopback_timer_stop_sync(struct loopback_pcm *dpcm)
 182 {
 183         del_timer_sync(&dpcm->timer);
 184 }
 185
 186 #define CABLE_VALID_PLAYBACK    (1 << SNDRV_PCM_STREAM_PLAYBACK)
 187 #define CABLE_VALID_CAPTURE     (1 << SNDRV_PCM_STREAM_CAPTURE)
 188 #define CABLE_VALID_BOTH        (CABLE_VALID_PLAYBACK|CABLE_VALID_CAPTURE)
 189
 190 static int loopback_check_format(struct loopback_cable *cable, int stream)
 191 {
 192         struct snd_pcm_runtime *runtime, *cruntime;
 193         struct loopback_setup *setup;
 194         struct snd_card *card;
 195         int check;
 196
 197         if (cable->valid != CABLE_VALID_BOTH) {
 198                 if (stream == SNDRV_PCM_STREAM_PLAYBACK)
 199                         goto __notify;
 200                 return 0;
 201         }
 202         runtime = cable->streams[SNDRV_PCM_STREAM_PLAYBACK]->
 203                                                         substream->runtime;
 204         cruntime = cable->streams[SNDRV_PCM_STREAM_CAPTURE]->
 205                                                         substream->runtime;
 206         check = runtime->format != cruntime->format ||
 207                 runtime->rate != cruntime->rate ||
 208                 runtime->channels != cruntime->channels;
 209         if (!check)
 210                 return 0;
 211         if (stream == SNDRV_PCM_STREAM_CAPTURE) {
 212                 return -EIO;
 213         } else {
 214                 snd_pcm_stop(cable->streams[SNDRV_PCM_STREAM_CAPTURE]->
 215                                         substream, SNDRV_PCM_STATE_DRAINING);
 216               __notify:
 217                 runtime = cable->streams[SNDRV_PCM_STREAM_PLAYBACK]->
 218                                                         substream->runtime;
 219                 setup = get_setup(cable->streams[SNDRV_PCM_STREAM_PLAYBACK]);
 220                 card = cable->streams[SNDRV_PCM_STREAM_PLAYBACK]->loopback->card;
 221                 if (setup->format != runtime->format) {
 222                         snd_ctl_notify(card, SNDRV_CTL_EVENT_MASK_VALUE,
 223                                                         &setup->format_id);
 224                         setup->format = runtime->format;
 225                 }
 226                 if (setup->rate != runtime->rate) {
 227                         snd_ctl_notify(card, SNDRV_CTL_EVENT_MASK_VALUE,
 228                                                         &setup->rate_id);
 229                         setup->rate = runtime->rate;
 230                 }
 231                 if (setup->channels != runtime->channels) {
 232                         snd_ctl_notify(card, SNDRV_CTL_EVENT_MASK_VALUE,
 233                                                         &setup->channels_id);
 234                         setup->channels = runtime->channels;
 235                 }
 236         }
 237         return 0;
 238 }
 239
 240 static void loopback_active_notify(struct loopback_pcm *dpcm)
 241 {
 242         snd_ctl_notify(dpcm->loopback->card,
 243                        SNDRV_CTL_EVENT_MASK_VALUE,
 244                        &get_setup(dpcm)->active_id);
 245 }
 246
 247 static int loopback_trigger(struct snd_pcm_substream *substream, int cmd)
 248 {
 249         struct snd_pcm_runtime *runtime = substream->runtime;
 250         struct loopback_pcm *dpcm = runtime->private_data;
 251         struct loopback_cable *cable = dpcm->cable;
 252         int err, stream = 1 << substream->stream;
 253
 254         switch (cmd) {
 255         case SNDRV_PCM_TRIGGER_START:
 256                 err = loopback_check_format(cable, substream->stream);
 257                 if (err < 0)
 258                         return err;
 259                 dpcm->last_jiffies = jiffies;
 260                 dpcm->pcm_rate_shift = 0;
 261                 dpcm->last_drift = 0;
 262                 spin_lock(&cable->lock);
 263                 cable->running |= stream;
 264                 cable->pause &= ~stream;
 265                 loopback_timer_start(dpcm);
 266                 spin_unlock(&cable->lock);
 267                 if (substream->stream == SNDRV_PCM_STREAM_PLAYBACK)
 268                         loopback_active_notify(dpcm);
 269                 break;
 270         case SNDRV_PCM_TRIGGER_STOP:
 271                 spin_lock(&cable->lock);
 272                 cable->running &= ~stream;
 273                 cable->pause &= ~stream;
 274                 loopback_timer_stop(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_PAUSE_PUSH:
 280         case SNDRV_PCM_TRIGGER_SUSPEND:
 281                 spin_lock(&cable->lock);
 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_RELEASE:
 289         case SNDRV_PCM_TRIGGER_RESUME:
 290                 spin_lock(&cable->lock);
 291                 dpcm->last_jiffies = jiffies;
 292                 cable->pause &= ~stream;
 293                 loopback_timer_start(dpcm);
 294                 spin_unlock(&cable->lock);
 295                 if (substream->stream == SNDRV_PCM_STREAM_PLAYBACK)
 296                         loopback_active_notify(dpcm);
 297                 break;
 298         default:
 299                 return -EINVAL;
 300         }
 301         return 0;
 302 }
 303
 304 static void params_change(struct snd_pcm_substream *substream)
 305 {
 306         struct snd_pcm_runtime *runtime = substream->runtime;
 307         struct loopback_pcm *dpcm = runtime->private_data;
 308         struct loopback_cable *cable = dpcm->cable;
 309
 310         cable->hw.formats = pcm_format_to_bits(runtime->format);
 311         cable->hw.rate_min = runtime->rate;
 312         cable->hw.rate_max = runtime->rate;
 313         cable->hw.channels_min = runtime->channels;
 314         cable->hw.channels_max = runtime->channels;
 315 }
 316
 317 static int loopback_prepare(struct snd_pcm_substream *substream)
 318 {
 319         struct snd_pcm_runtime *runtime = substream->runtime;
 320         struct loopback_pcm *dpcm = runtime->private_data;
 321         struct loopback_cable *cable = dpcm->cable;
 322         int bps, salign;
 323
 324         loopback_timer_stop_sync(dpcm);
 325
 326         salign = (snd_pcm_format_physical_width(runtime->format) *
 327                                                 runtime->channels) / 8;
 328         bps = salign * runtime->rate;
 329         if (bps <= 0 || salign <= 0)
 330                 return -EINVAL;
 331
 332         dpcm->buf_pos = 0;
 333         dpcm->pcm_buffer_size = frames_to_bytes(runtime, runtime->buffer_size);
 334         if (substream->stream == SNDRV_PCM_STREAM_CAPTURE) {
 335                 /* clear capture buffer */
 336                 dpcm->silent_size = dpcm->pcm_buffer_size;
 337                 snd_pcm_format_set_silence(runtime->format, runtime->dma_area,
 338                                            runtime->buffer_size * runtime->channels);
 339         }
 340
 341         dpcm->irq_pos = 0;
 342         dpcm->period_update_pending = 0;
 343         dpcm->pcm_bps = bps;
 344         dpcm->pcm_salign = salign;
 345         dpcm->pcm_period_size = frames_to_bytes(runtime, runtime->period_size);
 346
 347         mutex_lock(&dpcm->loopback->cable_lock);
 348         if (!(cable->valid & ~(1 << substream->stream)) ||
 349             (get_setup(dpcm)->notify &&
 350              substream->stream == SNDRV_PCM_STREAM_PLAYBACK))
 351                 params_change(substream);
 352         cable->valid |= 1 << substream->stream;
 353         mutex_unlock(&dpcm->loopback->cable_lock);
 354
 355         return 0;
 356 }
 357
 358 static void clear_capture_buf(struct loopback_pcm *dpcm, unsigned int bytes)
 359 {
 360         struct snd_pcm_runtime *runtime = dpcm->substream->runtime;
 361         char *dst = runtime->dma_area;
 362         unsigned int dst_off = dpcm->buf_pos;
 363
 364         if (dpcm->silent_size >= dpcm->pcm_buffer_size)
 365                 return;
 366         if (dpcm->silent_size + bytes > dpcm->pcm_buffer_size)
 367                 bytes = dpcm->pcm_buffer_size - dpcm->silent_size;
 368
 369         for (;;) {
 370                 unsigned int size = bytes;
 371                 if (dst_off + size > dpcm->pcm_buffer_size)
 372                         size = dpcm->pcm_buffer_size - dst_off;
 373                 snd_pcm_format_set_silence(runtime->format, dst + dst_off,
 374                                            bytes_to_frames(runtime, size) *
 375                                                 runtime->channels);
 376                 dpcm->silent_size += size;
 377                 bytes -= size;
 378                 if (!bytes)
 379                         break;
 380                 dst_off = 0;
 381         }
 382 }
 383
 384 static void copy_play_buf(struct loopback_pcm *play,
 385                           struct loopback_pcm *capt,
 386                           unsigned int bytes)
 387 {
 388         struct snd_pcm_runtime *runtime = play->substream->runtime;
 389         char *src = runtime->dma_area;
 390         char *dst = capt->substream->runtime->dma_area;
 391         unsigned int src_off = play->buf_pos;
 392         unsigned int dst_off = capt->buf_pos;
 393         unsigned int clear_bytes = 0;
 394
 395         /* check if playback is draining, trim the capture copy size
 396          * when our pointer is at the end of playback ring buffer */
 397         if (runtime->status->state == SNDRV_PCM_STATE_DRAINING &&
 398             snd_pcm_playback_hw_avail(runtime) < runtime->buffer_size) {
 399                 snd_pcm_uframes_t appl_ptr, appl_ptr1, diff;
 400                 appl_ptr = appl_ptr1 = runtime->control->appl_ptr;
 401                 appl_ptr1 -= appl_ptr1 % runtime->buffer_size;
 402                 appl_ptr1 += play->buf_pos / play->pcm_salign;
 403                 if (appl_ptr < appl_ptr1)
 404                         appl_ptr1 -= runtime->buffer_size;
 405                 diff = (appl_ptr - appl_ptr1) * play->pcm_salign;
 406                 if (diff < bytes) {
 407                         clear_bytes = bytes - diff;
 408                         bytes = diff;
 409                 }
 410         }
 411
 412         for (;;) {
 413                 unsigned int size = bytes;
 414                 if (src_off + size > play->pcm_buffer_size)
 415                         size = play->pcm_buffer_size - src_off;
 416                 if (dst_off + size > capt->pcm_buffer_size)
 417                         size = capt->pcm_buffer_size - dst_off;
 418                 memcpy(dst + dst_off, src + src_off, size);
 419                 capt->silent_size = 0;
 420                 bytes -= size;
 421                 if (!bytes)
 422                         break;
 423                 src_off = (src_off + size) % play->pcm_buffer_size;
 424                 dst_off = (dst_off + size) % capt->pcm_buffer_size;
 425         }
 426
 427         if (clear_bytes > 0) {
 428                 clear_capture_buf(capt, clear_bytes);
 429                 capt->silent_size = 0;
 430         }
 431 }
 432
 433 static inline unsigned int bytepos_delta(struct loopback_pcm *dpcm,
 434                                          unsigned int jiffies_delta)
 435 {
 436         unsigned long last_pos;
 437         unsigned int delta;
 438
 439         last_pos = byte_pos(dpcm, dpcm->irq_pos);
 440         dpcm->irq_pos += jiffies_delta * dpcm->pcm_bps;
 441         delta = byte_pos(dpcm, dpcm->irq_pos) - last_pos;
 442         if (delta >= dpcm->last_drift)
 443                 delta -= dpcm->last_drift;
 444         dpcm->last_drift = 0;
 445         if (dpcm->irq_pos >= dpcm->period_size_frac) {
 446                 dpcm->irq_pos %= dpcm->period_size_frac;
 447                 dpcm->period_update_pending = 1;
 448         }
 449         return delta;
 450 }
 451
 452 static inline void bytepos_finish(struct loopback_pcm *dpcm,
 453                                   unsigned int delta)
 454 {
 455         dpcm->buf_pos += delta;
 456         dpcm->buf_pos %= dpcm->pcm_buffer_size;
 457 }
 458
 459 /* call in cable->lock */
 460 static unsigned int loopback_pos_update(struct loopback_cable *cable)
 461 {
 462         struct loopback_pcm *dpcm_play =
 463                         cable->streams[SNDRV_PCM_STREAM_PLAYBACK];
 464         struct loopback_pcm *dpcm_capt =
 465                         cable->streams[SNDRV_PCM_STREAM_CAPTURE];
 466         unsigned long delta_play = 0, delta_capt = 0, cur_jiffies;
 467         unsigned int running, count1, count2;
 468
 469         cur_jiffies = jiffies;
 470         running = cable->running ^ cable->pause;
 471         if (running & (1 << SNDRV_PCM_STREAM_PLAYBACK)) {
 472                 delta_play = cur_jiffies - dpcm_play->last_jiffies;
 473                 dpcm_play->last_jiffies += delta_play;
 474         }
 475
 476         if (running & (1 << SNDRV_PCM_STREAM_CAPTURE)) {
 477                 delta_capt = cur_jiffies - dpcm_capt->last_jiffies;
 478                 dpcm_capt->last_jiffies += delta_capt;
 479         }
 480
 481         if (delta_play == 0 && delta_capt == 0)
 482                 goto unlock;
 483
 484         if (delta_play > delta_capt) {
 485                 count1 = bytepos_delta(dpcm_play, delta_play - delta_capt);
 486                 bytepos_finish(dpcm_play, count1);
 487                 delta_play = delta_capt;
 488         } else if (delta_play < delta_capt) {
 489                 count1 = bytepos_delta(dpcm_capt, delta_capt - delta_play);
 490                 clear_capture_buf(dpcm_capt, count1);
 491                 bytepos_finish(dpcm_capt, count1);
 492                 delta_capt = delta_play;
 493         }
 494
 495         if (delta_play == 0 && delta_capt == 0)
 496                 goto unlock;
 497
 498         /* note delta_capt == delta_play at this moment */
 499         count1 = bytepos_delta(dpcm_play, delta_play);
 500         count2 = bytepos_delta(dpcm_capt, delta_capt);
 501         if (count1 < count2) {
 502                 dpcm_capt->last_drift = count2 - count1;
 503                 count1 = count2;
 504         } else if (count1 > count2) {
 505                 dpcm_play->last_drift = count1 - count2;
 506         }
 507         copy_play_buf(dpcm_play, dpcm_capt, count1);
 508         bytepos_finish(dpcm_play, count1);
 509         bytepos_finish(dpcm_capt, count1);
 510  unlock:
 511         return running;
 512 }
 513
 514 static void loopback_timer_function(struct timer_list *t)
 515 {
 516         struct loopback_pcm *dpcm = from_timer(dpcm, t, timer);
 517         unsigned long flags;
 518
 519         spin_lock_irqsave(&dpcm->cable->lock, flags);
 520         if (loopback_pos_update(dpcm->cable) & (1 << dpcm->substream->stream)) {
 521                 loopback_timer_start(dpcm);
 522                 if (dpcm->period_update_pending) {
 523                         dpcm->period_update_pending = 0;
 524                         spin_unlock_irqrestore(&dpcm->cable->lock, flags);
 525                         /* need to unlock before calling below */
 526                         snd_pcm_period_elapsed(dpcm->substream);
 527                         return;
 528                 }
 529         }
 530         spin_unlock_irqrestore(&dpcm->cable->lock, flags);
 531 }
 532
 533 static snd_pcm_uframes_t loopback_pointer(struct snd_pcm_substream *substream)
 534 {
 535         struct snd_pcm_runtime *runtime = substream->runtime;
 536         struct loopback_pcm *dpcm = runtime->private_data;
 537         snd_pcm_uframes_t pos;
 538
 539         spin_lock(&dpcm->cable->lock);
 540         loopback_pos_update(dpcm->cable);
 541         pos = dpcm->buf_pos;
 542         spin_unlock(&dpcm->cable->lock);
 543         return bytes_to_frames(runtime, pos);
 544 }
 545
 546 static const struct snd_pcm_hardware loopback_pcm_hardware =
 547 {
 548         .info =         (SNDRV_PCM_INFO_INTERLEAVED | SNDRV_PCM_INFO_MMAP |
 549                          SNDRV_PCM_INFO_MMAP_VALID | SNDRV_PCM_INFO_PAUSE |
 550                          SNDRV_PCM_INFO_RESUME),
 551         .formats =      (SNDRV_PCM_FMTBIT_S16_LE | SNDRV_PCM_FMTBIT_S16_BE |
 552                          SNDRV_PCM_FMTBIT_S24_LE | SNDRV_PCM_FMTBIT_S24_BE |
 553                          SNDRV_PCM_FMTBIT_S24_3LE | SNDRV_PCM_FMTBIT_S24_3BE |
 554                          SNDRV_PCM_FMTBIT_S32_LE | SNDRV_PCM_FMTBIT_S32_BE |
 555                          SNDRV_PCM_FMTBIT_FLOAT_LE | SNDRV_PCM_FMTBIT_FLOAT_BE),
 556         .rates =        SNDRV_PCM_RATE_CONTINUOUS | SNDRV_PCM_RATE_8000_192000,
 557         .rate_min =             8000,
 558         .rate_max =             192000,
 559         .channels_min =         1,
 560         .channels_max =         32,
 561         .buffer_bytes_max =     2 * 1024 * 1024,
 562         .period_bytes_min =     64,
 563         /* note check overflow in frac_pos() using pcm_rate_shift before
 564            changing period_bytes_max value */
 565         .period_bytes_max =     1024 * 1024,
 566         .periods_min =          1,
 567         .periods_max =          1024,
 568         .fifo_size =            0,
 569 };
 570
 571 static void loopback_runtime_free(struct snd_pcm_runtime *runtime)
 572 {
 573         struct loopback_pcm *dpcm = runtime->private_data;
 574         kfree(dpcm);
 575 }
 576
 577 static int loopback_hw_params(struct snd_pcm_substream *substream,
 578                               struct snd_pcm_hw_params *params)
 579 {
 580         return snd_pcm_lib_alloc_vmalloc_buffer(substream,
 581                                                 params_buffer_bytes(params));
 582 }
 583
 584 static int loopback_hw_free(struct snd_pcm_substream *substream)
 585 {
 586         struct snd_pcm_runtime *runtime = substream->runtime;
 587         struct loopback_pcm *dpcm = runtime->private_data;
 588         struct loopback_cable *cable = dpcm->cable;
 589
 590         mutex_lock(&dpcm->loopback->cable_lock);
 591         cable->valid &= ~(1 << substream->stream);
 592         mutex_unlock(&dpcm->loopback->cable_lock);
 593         return snd_pcm_lib_free_vmalloc_buffer(substream);
 594 }
 595
 596 static unsigned int get_cable_index(struct snd_pcm_substream *substream)
 597 {
 598         if (!substream->pcm->device)
 599                 return substream->stream;
 600         else
 601                 return !substream->stream;
 602 }
 603
 604 static int rule_format(struct snd_pcm_hw_params *params,
 605                        struct snd_pcm_hw_rule *rule)
 606 {
 607         struct loopback_pcm *dpcm = rule->private;
 608         struct loopback_cable *cable = dpcm->cable;
 609         struct snd_mask m;
 610
 611         snd_mask_none(&m);
 612         mutex_lock(&dpcm->loopback->cable_lock);
 613         m.bits[0] = (u_int32_t)cable->hw.formats;
 614         m.bits[1] = (u_int32_t)(cable->hw.formats >> 32);
 615         mutex_unlock(&dpcm->loopback->cable_lock);
 616         return snd_mask_refine(hw_param_mask(params, rule->var), &m);
 617 }
 618
 619 static int rule_rate(struct snd_pcm_hw_params *params,
 620                      struct snd_pcm_hw_rule *rule)
 621 {
 622         struct loopback_pcm *dpcm = rule->private;
 623         struct loopback_cable *cable = dpcm->cable;
 624         struct snd_interval t;
 625
 626         mutex_lock(&dpcm->loopback->cable_lock);
 627         t.min = cable->hw.rate_min;
 628         t.max = cable->hw.rate_max;
 629         mutex_unlock(&dpcm->loopback->cable_lock);
 630         t.openmin = t.openmax = 0;
 631         t.integer = 0;
 632         return snd_interval_refine(hw_param_interval(params, rule->var), &t);
 633 }
 634
 635 static int rule_channels(struct snd_pcm_hw_params *params,
 636                          struct snd_pcm_hw_rule *rule)
 637 {
 638         struct loopback_pcm *dpcm = rule->private;
 639         struct loopback_cable *cable = dpcm->cable;
 640         struct snd_interval t;
 641
 642         mutex_lock(&dpcm->loopback->cable_lock);
 643         t.min = cable->hw.channels_min;
 644         t.max = cable->hw.channels_max;
 645         mutex_unlock(&dpcm->loopback->cable_lock);
 646         t.openmin = t.openmax = 0;
 647         t.integer = 0;
 648         return snd_interval_refine(hw_param_interval(params, rule->var), &t);
 649 }
 650
 651 static void free_cable(struct snd_pcm_substream *substream)
 652 {
 653         struct loopback *loopback = substream->private_data;
 654         int dev = get_cable_index(substream);
 655         struct loopback_cable *cable;
 656
 657         cable = loopback->cables[substream->number][dev];
 658         if (!cable)
 659                 return;
 660         if (cable->streams[!substream->stream]) {
 661                 /* other stream is still alive */
 662                 spin_lock_irq(&cable->lock);
 663                 cable->streams[substream->stream] = NULL;
 664                 spin_unlock_irq(&cable->lock);
 665         } else {
 666                 /* free the cable */
 667                 loopback->cables[substream->number][dev] = NULL;
 668                 kfree(cable);
 669         }
 670 }
 671
 672 static int loopback_open(struct snd_pcm_substream *substream)
 673 {
 674         struct snd_pcm_runtime *runtime = substream->runtime;
 675         struct loopback *loopback = substream->private_data;
 676         struct loopback_pcm *dpcm;
 677         struct loopback_cable *cable = NULL;
 678         int err = 0;
 679         int dev = get_cable_index(substream);
 680
 681         mutex_lock(&loopback->cable_lock);
 682         dpcm = kzalloc(sizeof(*dpcm), GFP_KERNEL);
 683         if (!dpcm) {
 684                 err = -ENOMEM;
 685                 goto unlock;
 686         }
 687         dpcm->loopback = loopback;
 688         dpcm->substream = substream;
 689         timer_setup(&dpcm->timer, loopback_timer_function, 0);
 690
 691         cable = loopback->cables[substream->number][dev];
 692         if (!cable) {
 693                 cable = kzalloc(sizeof(*cable), GFP_KERNEL);
 694                 if (!cable) {
 695                         err = -ENOMEM;
 696                         goto unlock;
 697                 }
 698                 spin_lock_init(&cable->lock);
 699                 cable->hw = loopback_pcm_hardware;
 700                 loopback->cables[substream->number][dev] = cable;
 701         }
 702         dpcm->cable = cable;
 703
 704         snd_pcm_hw_constraint_integer(runtime, SNDRV_PCM_HW_PARAM_PERIODS);
 705
 706         /* use dynamic rules based on actual runtime->hw values */
 707         /* note that the default rules created in the PCM midlevel code */
 708         /* are cached -> they do not reflect the actual state */
 709         err = snd_pcm_hw_rule_add(runtime, 0,
 710                                   SNDRV_PCM_HW_PARAM_FORMAT,
 711                                   rule_format, dpcm,
 712                                   SNDRV_PCM_HW_PARAM_FORMAT, -1);
 713         if (err < 0)
 714                 goto unlock;
 715         err = snd_pcm_hw_rule_add(runtime, 0,
 716                                   SNDRV_PCM_HW_PARAM_RATE,
 717                                   rule_rate, dpcm,
 718                                   SNDRV_PCM_HW_PARAM_RATE, -1);
 719         if (err < 0)
 720                 goto unlock;
 721         err = snd_pcm_hw_rule_add(runtime, 0,
 722                                   SNDRV_PCM_HW_PARAM_CHANNELS,
 723                                   rule_channels, dpcm,
 724                                   SNDRV_PCM_HW_PARAM_CHANNELS, -1);
 725         if (err < 0)
 726                 goto unlock;
 727
 728         runtime->private_data = dpcm;
 729         runtime->private_free = loopback_runtime_free;
 730         if (get_notify(dpcm))
 731                 runtime->hw = loopback_pcm_hardware;
 732         else
 733                 runtime->hw = cable->hw;
 734
 735         spin_lock_irq(&cable->lock);
 736         cable->streams[substream->stream] = dpcm;
 737         spin_unlock_irq(&cable->lock);
 738
 739  unlock:
 740         if (err < 0) {
 741                 free_cable(substream);
 742                 kfree(dpcm);
 743         }
 744         mutex_unlock(&loopback->cable_lock);
 745         return err;
 746 }
 747
 748 static int loopback_close(struct snd_pcm_substream *substream)
 749 {
 750         struct loopback *loopback = substream->private_data;
 751         struct loopback_pcm *dpcm = substream->runtime->private_data;
 752
 753         loopback_timer_stop_sync(dpcm);
 754         mutex_lock(&loopback->cable_lock);
 755         free_cable(substream);
 756         mutex_unlock(&loopback->cable_lock);
 757         return 0;
 758 }
 759
 760 static const struct snd_pcm_ops loopback_pcm_ops = {
 761         .open =         loopback_open,
 762         .close =        loopback_close,
 763         .ioctl =        snd_pcm_lib_ioctl,
 764         .hw_params =    loopback_hw_params,
 765         .hw_free =      loopback_hw_free,
 766         .prepare =      loopback_prepare,
 767         .trigger =      loopback_trigger,
 768         .pointer =      loopback_pointer,
 769         .page =         snd_pcm_lib_get_vmalloc_page,
 770 };
 771
 772 static int loopback_pcm_new(struct loopback *loopback,
 773                             int device, int substreams)
 774 {
 775         struct snd_pcm *pcm;
 776         int err;
 777
 778         err = snd_pcm_new(loopback->card, "Loopback PCM", device,
 779                           substreams, substreams, &pcm);
 780         if (err < 0)
 781                 return err;
 782         snd_pcm_set_ops(pcm, SNDRV_PCM_STREAM_PLAYBACK, &loopback_pcm_ops);
 783         snd_pcm_set_ops(pcm, SNDRV_PCM_STREAM_CAPTURE, &loopback_pcm_ops);
 784
 785         pcm->private_data = loopback;
 786         pcm->info_flags = 0;
 787         strcpy(pcm->name, "Loopback PCM");
 788
 789         loopback->pcm[device] = pcm;
 790         return 0;
 791 }
 792
 793 static int loopback_rate_shift_info(struct snd_kcontrol *kcontrol,
 794                                     struct snd_ctl_elem_info *uinfo)
 795 {
 796         uinfo->type = SNDRV_CTL_ELEM_TYPE_INTEGER;
 797         uinfo->count = 1;
 798         uinfo->value.integer.min = 80000;
 799         uinfo->value.integer.max = 120000;
 800         uinfo->value.integer.step = 1;
 801         return 0;
 802 }
 803
 804 static int loopback_rate_shift_get(struct snd_kcontrol *kcontrol,
 805                                    struct snd_ctl_elem_value *ucontrol)
 806 {
 807         struct loopback *loopback = snd_kcontrol_chip(kcontrol);
 808
 809         mutex_lock(&loopback->cable_lock);
 810         ucontrol->value.integer.value[0] =
 811                 loopback->setup[kcontrol->id.subdevice]
 812                                [kcontrol->id.device].rate_shift;
 813         mutex_unlock(&loopback->cable_lock);
 814         return 0;
 815 }
 816
 817 static int loopback_rate_shift_put(struct snd_kcontrol *kcontrol,
 818                                    struct snd_ctl_elem_value *ucontrol)
 819 {
 820         struct loopback *loopback = snd_kcontrol_chip(kcontrol);
 821         unsigned int val;
 822         int change = 0;
 823
 824         val = ucontrol->value.integer.value[0];
 825         if (val < 80000)
 826                 val = 80000;
 827         if (val > 120000)
 828                 val = 120000;
 829         mutex_lock(&loopback->cable_lock);
 830         if (val != loopback->setup[kcontrol->id.subdevice]
 831                                   [kcontrol->id.device].rate_shift) {
 832                 loopback->setup[kcontrol->id.subdevice]
 833                                [kcontrol->id.device].rate_shift = val;
 834                 change = 1;
 835         }
 836         mutex_unlock(&loopback->cable_lock);
 837         return change;
 838 }
 839
 840 static int loopback_notify_get(struct snd_kcontrol *kcontrol,
 841                                struct snd_ctl_elem_value *ucontrol)
 842 {
 843         struct loopback *loopback = snd_kcontrol_chip(kcontrol);
 844
 845         mutex_lock(&loopback->cable_lock);
 846         ucontrol->value.integer.value[0] =
 847                 loopback->setup[kcontrol->id.subdevice]
 848                                [kcontrol->id.device].notify;
 849         mutex_unlock(&loopback->cable_lock);
 850         return 0;
 851 }
 852
 853 static int loopback_notify_put(struct snd_kcontrol *kcontrol,
 854                                struct snd_ctl_elem_value *ucontrol)
 855 {
 856         struct loopback *loopback = snd_kcontrol_chip(kcontrol);
 857         unsigned int val;
 858         int change = 0;
 859
 860         val = ucontrol->value.integer.value[0] ? 1 : 0;
 861         mutex_lock(&loopback->cable_lock);
 862         if (val != loopback->setup[kcontrol->id.subdevice]
 863                                 [kcontrol->id.device].notify) {
 864                 loopback->setup[kcontrol->id.subdevice]
 865                         [kcontrol->id.device].notify = val;
 866                 change = 1;
 867         }
 868         mutex_unlock(&loopback->cable_lock);
 869         return change;
 870 }
 871
 872 static int loopback_active_get(struct snd_kcontrol *kcontrol,
 873                                struct snd_ctl_elem_value *ucontrol)
 874 {
 875         struct loopback *loopback = snd_kcontrol_chip(kcontrol);
 876         struct loopback_cable *cable;
 877
 878         unsigned int val = 0;
 879
 880         mutex_lock(&loopback->cable_lock);
 881         cable = loopback->cables[kcontrol->id.subdevice][kcontrol->id.device ^ 1];
 882         if (cable != NULL) {
 883                 unsigned int running = cable->running ^ cable->pause;
 884
 885                 val = (running & (1 << SNDRV_PCM_STREAM_PLAYBACK)) ? 1 : 0;
 886         }
 887         mutex_unlock(&loopback->cable_lock);
 888         ucontrol->value.integer.value[0] = val;
 889         return 0;
 890 }
 891
 892 static int loopback_format_info(struct snd_kcontrol *kcontrol,
 893                                 struct snd_ctl_elem_info *uinfo)
 894 {
 895         uinfo->type = SNDRV_CTL_ELEM_TYPE_INTEGER;
 896         uinfo->count = 1;
 897         uinfo->value.integer.min = 0;
 898         uinfo->value.integer.max = SNDRV_PCM_FORMAT_LAST;
 899         uinfo->value.integer.step = 1;
 900         return 0;
 901 }
 902
 903 static int loopback_format_get(struct snd_kcontrol *kcontrol,
 904                                struct snd_ctl_elem_value *ucontrol)
 905 {
 906         struct loopback *loopback = snd_kcontrol_chip(kcontrol);
 907
 908         ucontrol->value.integer.value[0] =
 909                 loopback->setup[kcontrol->id.subdevice]
 910                                [kcontrol->id.device].format;
 911         return 0;
 912 }
 913
 914 static int loopback_rate_info(struct snd_kcontrol *kcontrol,
 915                               struct snd_ctl_elem_info *uinfo)
 916 {
 917         uinfo->type = SNDRV_CTL_ELEM_TYPE_INTEGER;
 918         uinfo->count = 1;
 919         uinfo->value.integer.min = 0;
 920         uinfo->value.integer.max = 192000;
 921         uinfo->value.integer.step = 1;
 922         return 0;
 923 }
 924
 925 static int loopback_rate_get(struct snd_kcontrol *kcontrol,
 926                              struct snd_ctl_elem_value *ucontrol)
 927 {
 928         struct loopback *loopback = snd_kcontrol_chip(kcontrol);
 929
 930         mutex_lock(&loopback->cable_lock);
 931         ucontrol->value.integer.value[0] =
 932                 loopback->setup[kcontrol->id.subdevice]
 933                                [kcontrol->id.device].rate;
 934         mutex_unlock(&loopback->cable_lock);
 935         return 0;
 936 }
 937
 938 static int loopback_channels_info(struct snd_kcontrol *kcontrol,
 939                                   struct snd_ctl_elem_info *uinfo)
 940 {
 941         uinfo->type = SNDRV_CTL_ELEM_TYPE_INTEGER;
 942         uinfo->count = 1;
 943         uinfo->value.integer.min = 1;
 944         uinfo->value.integer.max = 1024;
 945         uinfo->value.integer.step = 1;
 946         return 0;
 947 }
 948
 949 static int loopback_channels_get(struct snd_kcontrol *kcontrol,
 950                                  struct snd_ctl_elem_value *ucontrol)
 951 {
 952         struct loopback *loopback = snd_kcontrol_chip(kcontrol);
 953
 954         mutex_lock(&loopback->cable_lock);
 955         ucontrol->value.integer.value[0] =
 956                 loopback->setup[kcontrol->id.subdevice]
 957                                [kcontrol->id.device].channels;
 958         mutex_unlock(&loopback->cable_lock);
 959         return 0;
 960 }
 961
 962 static struct snd_kcontrol_new loopback_controls[]  = {
 963 {
 964         .iface =        SNDRV_CTL_ELEM_IFACE_PCM,
 965         .name =         "PCM Rate Shift 100000",
 966         .info =         loopback_rate_shift_info,
 967         .get =          loopback_rate_shift_get,
 968         .put =          loopback_rate_shift_put,
 969 },
 970 {
 971         .iface =        SNDRV_CTL_ELEM_IFACE_PCM,
 972         .name =         "PCM Notify",
 973         .info =         snd_ctl_boolean_mono_info,
 974         .get =          loopback_notify_get,
 975         .put =          loopback_notify_put,
 976 },
 977 #define ACTIVE_IDX 2
 978 {
 979         .access =       SNDRV_CTL_ELEM_ACCESS_READ,
 980         .iface =        SNDRV_CTL_ELEM_IFACE_PCM,
 981         .name =         "PCM Slave Active",
 982         .info =         snd_ctl_boolean_mono_info,
 983         .get =          loopback_active_get,
 984 },
 985 #define FORMAT_IDX 3
 986 {
 987         .access =       SNDRV_CTL_ELEM_ACCESS_READ,
 988         .iface =        SNDRV_CTL_ELEM_IFACE_PCM,
 989         .name =         "PCM Slave Format",
 990         .info =         loopback_format_info,
 991         .get =          loopback_format_get
 992 },
 993 #define RATE_IDX 4
 994 {
 995         .access =       SNDRV_CTL_ELEM_ACCESS_READ,
 996         .iface =        SNDRV_CTL_ELEM_IFACE_PCM,
 997         .name =         "PCM Slave Rate",
 998         .info =         loopback_rate_info,
 999         .get =          loopback_rate_get
1000 },
1001 #define CHANNELS_IDX 5
1002 {
1003         .access =       SNDRV_CTL_ELEM_ACCESS_READ,
1004         .iface =        SNDRV_CTL_ELEM_IFACE_PCM,
1005         .name =         "PCM Slave Channels",
1006         .info =         loopback_channels_info,
1007         .get =          loopback_channels_get
1008 }
1009 };
1010
1011 static int loopback_mixer_new(struct loopback *loopback, int notify)
1012 {
1013         struct snd_card *card = loopback->card;
1014         struct snd_pcm *pcm;
1015         struct snd_kcontrol *kctl;
1016         struct loopback_setup *setup;
1017         int err, dev, substr, substr_count, idx;
1018
1019         strcpy(card->mixername, "Loopback Mixer");
1020         for (dev = 0; dev < 2; dev++) {
1021                 pcm = loopback->pcm[dev];
1022                 substr_count =
1023                     pcm->streams[SNDRV_PCM_STREAM_CAPTURE].substream_count;
1024                 for (substr = 0; substr < substr_count; substr++) {
1025                         setup = &loopback->setup[substr][dev];
1026                         setup->notify = notify;
1027                         setup->rate_shift = NO_PITCH;
1028                         setup->format = SNDRV_PCM_FORMAT_S16_LE;
1029                         setup->rate = 48000;
1030                         setup->channels = 2;
1031                         for (idx = 0; idx < ARRAY_SIZE(loopback_controls);
1032                                                                         idx++) {
1033                                 kctl = snd_ctl_new1(&loopback_controls[idx],
1034                                                     loopback);
1035                                 if (!kctl)
1036                                         return -ENOMEM;
1037                                 kctl->id.device = dev;
1038                                 kctl->id.subdevice = substr;
1039
1040                                 /* Add the control before copying the id so that
1041                                  * the numid field of the id is set in the copy.
1042                                  */
1043                                 err = snd_ctl_add(card, kctl);
1044                                 if (err < 0)
1045                                         return err;
1046
1047                                 switch (idx) {
1048                                 case ACTIVE_IDX:
1049                                         setup->active_id = kctl->id;
1050                                         break;
1051                                 case FORMAT_IDX:
1052                                         setup->format_id = kctl->id;
1053                                         break;
1054                                 case RATE_IDX:
1055                                         setup->rate_id = kctl->id;
1056                                         break;
1057                                 case CHANNELS_IDX:
1058                                         setup->channels_id = kctl->id;
1059                                         break;
1060                                 default:
1061                                         break;
1062                                 }
1063                         }
1064                 }
1065         }
1066         return 0;
1067 }
1068
1069 static void print_dpcm_info(struct snd_info_buffer *buffer,
1070                             struct loopback_pcm *dpcm,
1071                             const char *id)
1072 {
1073         snd_iprintf(buffer, "  %s\n", id);
1074         if (dpcm == NULL) {
1075                 snd_iprintf(buffer, "    inactive\n");
1076                 return;
1077         }
1078         snd_iprintf(buffer, "    buffer_size:\t%u\n", dpcm->pcm_buffer_size);
1079         snd_iprintf(buffer, "    buffer_pos:\t\t%u\n", dpcm->buf_pos);
1080         snd_iprintf(buffer, "    silent_size:\t%u\n", dpcm->silent_size);
1081         snd_iprintf(buffer, "    period_size:\t%u\n", dpcm->pcm_period_size);
1082         snd_iprintf(buffer, "    bytes_per_sec:\t%u\n", dpcm->pcm_bps);
1083         snd_iprintf(buffer, "    sample_align:\t%u\n", dpcm->pcm_salign);
1084         snd_iprintf(buffer, "    rate_shift:\t\t%u\n", dpcm->pcm_rate_shift);
1085         snd_iprintf(buffer, "    update_pending:\t%u\n",
1086                                                 dpcm->period_update_pending);
1087         snd_iprintf(buffer, "    irq_pos:\t\t%u\n", dpcm->irq_pos);
1088         snd_iprintf(buffer, "    period_frac:\t%u\n", dpcm->period_size_frac);
1089         snd_iprintf(buffer, "    last_jiffies:\t%lu (%lu)\n",
1090                                         dpcm->last_jiffies, jiffies);
1091         snd_iprintf(buffer, "    timer_expires:\t%lu\n", dpcm->timer.expires);
1092 }
1093
1094 static void print_substream_info(struct snd_info_buffer *buffer,
1095                                  struct loopback *loopback,
1096                                  int sub,
1097                                  int num)
1098 {
1099         struct loopback_cable *cable = loopback->cables[sub][num];
1100
1101         snd_iprintf(buffer, "Cable %i substream %i:\n", num, sub);
1102         if (cable == NULL) {
1103                 snd_iprintf(buffer, "  inactive\n");
1104                 return;
1105         }
1106         snd_iprintf(buffer, "  valid: %u\n", cable->valid);
1107         snd_iprintf(buffer, "  running: %u\n", cable->running);
1108         snd_iprintf(buffer, "  pause: %u\n", cable->pause);
1109         print_dpcm_info(buffer, cable->streams[0], "Playback");
1110         print_dpcm_info(buffer, cable->streams[1], "Capture");
1111 }
1112
1113 static void print_cable_info(struct snd_info_entry *entry,
1114                              struct snd_info_buffer *buffer)
1115 {
1116         struct loopback *loopback = entry->private_data;
1117         int sub, num;
1118
1119         mutex_lock(&loopback->cable_lock);
1120         num = entry->name[strlen(entry->name)-1];
1121         num = num == '0' ? 0 : 1;
1122         for (sub = 0; sub < MAX_PCM_SUBSTREAMS; sub++)
1123                 print_substream_info(buffer, loopback, sub, num);
1124         mutex_unlock(&loopback->cable_lock);
1125 }
1126
1127 static int loopback_proc_new(struct loopback *loopback, int cidx)
1128 {
1129         char name[32];
1130
1131         snprintf(name, sizeof(name), "cable#%d", cidx);
1132         return snd_card_ro_proc_new(loopback->card, name, loopback,
1133                                     print_cable_info);
1134 }
1135
1136 static int loopback_probe(struct platform_device *devptr)
1137 {
1138         struct snd_card *card;
1139         struct loopback *loopback;
1140         int dev = devptr->id;
1141         int err;
1142
1143         err = snd_card_new(&devptr->dev, index[dev], id[dev], THIS_MODULE,
1144                            sizeof(struct loopback), &card);
1145         if (err < 0)
1146                 return err;
1147         loopback = card->private_data;
1148
1149         if (pcm_substreams[dev] < 1)
1150                 pcm_substreams[dev] = 1;
1151         if (pcm_substreams[dev] > MAX_PCM_SUBSTREAMS)
1152                 pcm_substreams[dev] = MAX_PCM_SUBSTREAMS;
1153
1154         loopback->card = card;
1155         mutex_init(&loopback->cable_lock);
1156
1157         err = loopback_pcm_new(loopback, 0, pcm_substreams[dev]);
1158         if (err < 0)
1159                 goto __nodev;
1160         err = loopback_pcm_new(loopback, 1, pcm_substreams[dev]);
1161         if (err < 0)
1162                 goto __nodev;
1163         err = loopback_mixer_new(loopback, pcm_notify[dev] ? 1 : 0);
1164         if (err < 0)
1165                 goto __nodev;
1166         loopback_proc_new(loopback, 0);
1167         loopback_proc_new(loopback, 1);
1168         strcpy(card->driver, "Loopback");
1169         strcpy(card->shortname, "Loopback");
1170         sprintf(card->longname, "Loopback %i", dev + 1);
1171         err = snd_card_register(card);
1172         if (!err) {
1173                 platform_set_drvdata(devptr, card);
1174                 return 0;
1175         }
1176       __nodev:
1177         snd_card_free(card);
1178         return err;
1179 }
1180
1181 static int loopback_remove(struct platform_device *devptr)
1182 {
1183         snd_card_free(platform_get_drvdata(devptr));
1184         return 0;
1185 }
1186
1187 #ifdef CONFIG_PM_SLEEP
1188 static int loopback_suspend(struct device *pdev)
1189 {
1190         struct snd_card *card = dev_get_drvdata(pdev);
1191
1192         snd_power_change_state(card, SNDRV_CTL_POWER_D3hot);
1193         return 0;
1194 }
1195
1196 static int loopback_resume(struct device *pdev)
1197 {
1198         struct snd_card *card = dev_get_drvdata(pdev);
1199
1200         snd_power_change_state(card, SNDRV_CTL_POWER_D0);
1201         return 0;
1202 }
1203
1204 static SIMPLE_DEV_PM_OPS(loopback_pm, loopback_suspend, loopback_resume);
1205 #define LOOPBACK_PM_OPS &loopback_pm
1206 #else
1207 #define LOOPBACK_PM_OPS NULL
1208 #endif
1209
1210 #define SND_LOOPBACK_DRIVER     "snd_aloop"
1211
1212 static struct platform_driver loopback_driver = {
1213         .probe          = loopback_probe,
1214         .remove         = loopback_remove,
1215         .driver         = {
1216                 .name   = SND_LOOPBACK_DRIVER,
1217                 .pm     = LOOPBACK_PM_OPS,
1218         },
1219 };
1220
1221 static void loopback_unregister_all(void)
1222 {
1223         int i;
1224
1225         for (i = 0; i < ARRAY_SIZE(devices); ++i)
1226                 platform_device_unregister(devices[i]);
1227         platform_driver_unregister(&loopback_driver);
1228 }
1229
1230 static int __init alsa_card_loopback_init(void)
1231 {
1232         int i, err, cards;
1233
1234         err = platform_driver_register(&loopback_driver);
1235         if (err < 0)
1236                 return err;
1237
1238
1239         cards = 0;
1240         for (i = 0; i < SNDRV_CARDS; i++) {
1241                 struct platform_device *device;
1242                 if (!enable[i])
1243                         continue;
1244                 device = platform_device_register_simple(SND_LOOPBACK_DRIVER,
1245                                                          i, NULL, 0);
1246                 if (IS_ERR(device))
1247                         continue;
1248                 if (!platform_get_drvdata(device)) {
1249                         platform_device_unregister(device);
1250                         continue;
1251                 }
1252                 devices[i] = device;
1253                 cards++;
1254         }
1255         if (!cards) {
1256 #ifdef MODULE
1257                 printk(KERN_ERR "aloop: No loopback enabled\n");
1258 #endif
1259                 loopback_unregister_all();
1260                 return -ENODEV;
1261         }
1262         return 0;
1263 }
1264
1265 static void __exit alsa_card_loopback_exit(void)
1266 {
1267         loopback_unregister_all();
1268 }
1269
1270 module_init(alsa_card_loopback_init)
1271 module_exit(alsa_card_loopback_exit)