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;
 467         unsigned int running, count1, count2;
 468
 469         running = cable->running ^ cable->pause;
 470         if (running & (1 << SNDRV_PCM_STREAM_PLAYBACK)) {
 471                 delta_play = jiffies - dpcm_play->last_jiffies;
 472                 dpcm_play->last_jiffies += delta_play;
 473         }
 474
 475         if (running & (1 << SNDRV_PCM_STREAM_CAPTURE)) {
 476                 delta_capt = jiffies - dpcm_capt->last_jiffies;
 477                 dpcm_capt->last_jiffies += delta_capt;
 478         }
 479
 480         if (delta_play == 0 && delta_capt == 0)
 481                 goto unlock;
 482
 483         if (delta_play > delta_capt) {
 484                 count1 = bytepos_delta(dpcm_play, delta_play - delta_capt);
 485                 bytepos_finish(dpcm_play, count1);
 486                 delta_play = delta_capt;
 487         } else if (delta_play < delta_capt) {
 488                 count1 = bytepos_delta(dpcm_capt, delta_capt - delta_play);
 489                 clear_capture_buf(dpcm_capt, count1);
 490                 bytepos_finish(dpcm_capt, count1);
 491                 delta_capt = delta_play;
 492         }
 493
 494         if (delta_play == 0 && delta_capt == 0)
 495                 goto unlock;
 496
 497         /* note delta_capt == delta_play at this moment */
 498         count1 = bytepos_delta(dpcm_play, delta_play);
 499         count2 = bytepos_delta(dpcm_capt, delta_capt);
 500         if (count1 < count2) {
 501                 dpcm_capt->last_drift = count2 - count1;
 502                 count1 = count2;
 503         } else if (count1 > count2) {
 504                 dpcm_play->last_drift = count1 - count2;
 505         }
 506         copy_play_buf(dpcm_play, dpcm_capt, count1);
 507         bytepos_finish(dpcm_play, count1);
 508         bytepos_finish(dpcm_capt, count1);
 509  unlock:
 510         return running;
 511 }
 512
 513 static void loopback_timer_function(struct timer_list *t)
 514 {
 515         struct loopback_pcm *dpcm = from_timer(dpcm, t, timer);
 516         unsigned long flags;
 517
 518         spin_lock_irqsave(&dpcm->cable->lock, flags);
 519         if (loopback_pos_update(dpcm->cable) & (1 << dpcm->substream->stream)) {
 520                 loopback_timer_start(dpcm);
 521                 if (dpcm->period_update_pending) {
 522                         dpcm->period_update_pending = 0;
 523                         spin_unlock_irqrestore(&dpcm->cable->lock, flags);
 524                         /* need to unlock before calling below */
 525                         snd_pcm_period_elapsed(dpcm->substream);
 526                         return;
 527                 }
 528         }
 529         spin_unlock_irqrestore(&dpcm->cable->lock, flags);
 530 }
 531
 532 static snd_pcm_uframes_t loopback_pointer(struct snd_pcm_substream *substream)
 533 {
 534         struct snd_pcm_runtime *runtime = substream->runtime;
 535         struct loopback_pcm *dpcm = runtime->private_data;
 536         snd_pcm_uframes_t pos;
 537
 538         spin_lock(&dpcm->cable->lock);
 539         loopback_pos_update(dpcm->cable);
 540         pos = dpcm->buf_pos;
 541         spin_unlock(&dpcm->cable->lock);
 542         return bytes_to_frames(runtime, pos);
 543 }
 544
 545 static const struct snd_pcm_hardware loopback_pcm_hardware =
 546 {
 547         .info =         (SNDRV_PCM_INFO_INTERLEAVED | SNDRV_PCM_INFO_MMAP |
 548                          SNDRV_PCM_INFO_MMAP_VALID | SNDRV_PCM_INFO_PAUSE |
 549                          SNDRV_PCM_INFO_RESUME),
 550         .formats =      (SNDRV_PCM_FMTBIT_S16_LE | SNDRV_PCM_FMTBIT_S16_BE |
 551                          SNDRV_PCM_FMTBIT_S24_LE | SNDRV_PCM_FMTBIT_S24_BE |
 552                          SNDRV_PCM_FMTBIT_S24_3LE | SNDRV_PCM_FMTBIT_S24_3BE |
 553                          SNDRV_PCM_FMTBIT_S32_LE | SNDRV_PCM_FMTBIT_S32_BE |
 554                          SNDRV_PCM_FMTBIT_FLOAT_LE | SNDRV_PCM_FMTBIT_FLOAT_BE),
 555         .rates =        SNDRV_PCM_RATE_CONTINUOUS | SNDRV_PCM_RATE_8000_192000,
 556         .rate_min =             8000,
 557         .rate_max =             192000,
 558         .channels_min =         1,
 559         .channels_max =         32,
 560         .buffer_bytes_max =     2 * 1024 * 1024,
 561         .period_bytes_min =     64,
 562         /* note check overflow in frac_pos() using pcm_rate_shift before
 563            changing period_bytes_max value */
 564         .period_bytes_max =     1024 * 1024,
 565         .periods_min =          1,
 566         .periods_max =          1024,
 567         .fifo_size =            0,
 568 };
 569
 570 static void loopback_runtime_free(struct snd_pcm_runtime *runtime)
 571 {
 572         struct loopback_pcm *dpcm = runtime->private_data;
 573         kfree(dpcm);
 574 }
 575
 576 static int loopback_hw_params(struct snd_pcm_substream *substream,
 577                               struct snd_pcm_hw_params *params)
 578 {
 579         return snd_pcm_lib_malloc_pages(substream, params_buffer_bytes(params));
 580 }
 581
 582 static int loopback_hw_free(struct snd_pcm_substream *substream)
 583 {
 584         struct snd_pcm_runtime *runtime = substream->runtime;
 585         struct loopback_pcm *dpcm = runtime->private_data;
 586         struct loopback_cable *cable = dpcm->cable;
 587
 588         mutex_lock(&dpcm->loopback->cable_lock);
 589         cable->valid &= ~(1 << substream->stream);
 590         mutex_unlock(&dpcm->loopback->cable_lock);
 591         return snd_pcm_lib_free_pages(substream);
 592 }
 593
 594 static unsigned int get_cable_index(struct snd_pcm_substream *substream)
 595 {
 596         if (!substream->pcm->device)
 597                 return substream->stream;
 598         else
 599                 return !substream->stream;
 600 }
 601
 602 static int rule_format(struct snd_pcm_hw_params *params,
 603                        struct snd_pcm_hw_rule *rule)
 604 {
 605         struct loopback_pcm *dpcm = rule->private;
 606         struct loopback_cable *cable = dpcm->cable;
 607         struct snd_mask m;
 608
 609         snd_mask_none(&m);
 610         mutex_lock(&dpcm->loopback->cable_lock);
 611         m.bits[0] = (u_int32_t)cable->hw.formats;
 612         m.bits[1] = (u_int32_t)(cable->hw.formats >> 32);
 613         mutex_unlock(&dpcm->loopback->cable_lock);
 614         return snd_mask_refine(hw_param_mask(params, rule->var), &m);
 615 }
 616
 617 static int rule_rate(struct snd_pcm_hw_params *params,
 618                      struct snd_pcm_hw_rule *rule)
 619 {
 620         struct loopback_pcm *dpcm = rule->private;
 621         struct loopback_cable *cable = dpcm->cable;
 622         struct snd_interval t;
 623
 624         mutex_lock(&dpcm->loopback->cable_lock);
 625         t.min = cable->hw.rate_min;
 626         t.max = cable->hw.rate_max;
 627         mutex_unlock(&dpcm->loopback->cable_lock);
 628         t.openmin = t.openmax = 0;
 629         t.integer = 0;
 630         return snd_interval_refine(hw_param_interval(params, rule->var), &t);
 631 }
 632
 633 static int rule_channels(struct snd_pcm_hw_params *params,
 634                          struct snd_pcm_hw_rule *rule)
 635 {
 636         struct loopback_pcm *dpcm = rule->private;
 637         struct loopback_cable *cable = dpcm->cable;
 638         struct snd_interval t;
 639
 640         mutex_lock(&dpcm->loopback->cable_lock);
 641         t.min = cable->hw.channels_min;
 642         t.max = cable->hw.channels_max;
 643         mutex_unlock(&dpcm->loopback->cable_lock);
 644         t.openmin = t.openmax = 0;
 645         t.integer = 0;
 646         return snd_interval_refine(hw_param_interval(params, rule->var), &t);
 647 }
 648
 649 static void free_cable(struct snd_pcm_substream *substream)
 650 {
 651         struct loopback *loopback = substream->private_data;
 652         int dev = get_cable_index(substream);
 653         struct loopback_cable *cable;
 654
 655         cable = loopback->cables[substream->number][dev];
 656         if (!cable)
 657                 return;
 658         if (cable->streams[!substream->stream]) {
 659                 /* other stream is still alive */
 660                 spin_lock_irq(&cable->lock);
 661                 cable->streams[substream->stream] = NULL;
 662                 spin_unlock_irq(&cable->lock);
 663         } else {
 664                 /* free the cable */
 665                 loopback->cables[substream->number][dev] = NULL;
 666                 kfree(cable);
 667         }
 668 }
 669
 670 static int loopback_open(struct snd_pcm_substream *substream)
 671 {
 672         struct snd_pcm_runtime *runtime = substream->runtime;
 673         struct loopback *loopback = substream->private_data;
 674         struct loopback_pcm *dpcm;
 675         struct loopback_cable *cable = NULL;
 676         int err = 0;
 677         int dev = get_cable_index(substream);
 678
 679         mutex_lock(&loopback->cable_lock);
 680         dpcm = kzalloc(sizeof(*dpcm), GFP_KERNEL);
 681         if (!dpcm) {
 682                 err = -ENOMEM;
 683                 goto unlock;
 684         }
 685         dpcm->loopback = loopback;
 686         dpcm->substream = substream;
 687         timer_setup(&dpcm->timer, loopback_timer_function, 0);
 688
 689         cable = loopback->cables[substream->number][dev];
 690         if (!cable) {
 691                 cable = kzalloc(sizeof(*cable), GFP_KERNEL);
 692                 if (!cable) {
 693                         err = -ENOMEM;
 694                         goto unlock;
 695                 }
 696                 spin_lock_init(&cable->lock);
 697                 cable->hw = loopback_pcm_hardware;
 698                 loopback->cables[substream->number][dev] = cable;
 699         }
 700         dpcm->cable = cable;
 701
 702         snd_pcm_hw_constraint_integer(runtime, SNDRV_PCM_HW_PARAM_PERIODS);
 703
 704         /* use dynamic rules based on actual runtime->hw values */
 705         /* note that the default rules created in the PCM midlevel code */
 706         /* are cached -> they do not reflect the actual state */
 707         err = snd_pcm_hw_rule_add(runtime, 0,
 708                                   SNDRV_PCM_HW_PARAM_FORMAT,
 709                                   rule_format, dpcm,
 710                                   SNDRV_PCM_HW_PARAM_FORMAT, -1);
 711         if (err < 0)
 712                 goto unlock;
 713         err = snd_pcm_hw_rule_add(runtime, 0,
 714                                   SNDRV_PCM_HW_PARAM_RATE,
 715                                   rule_rate, dpcm,
 716                                   SNDRV_PCM_HW_PARAM_RATE, -1);
 717         if (err < 0)
 718                 goto unlock;
 719         err = snd_pcm_hw_rule_add(runtime, 0,
 720                                   SNDRV_PCM_HW_PARAM_CHANNELS,
 721                                   rule_channels, dpcm,
 722                                   SNDRV_PCM_HW_PARAM_CHANNELS, -1);
 723         if (err < 0)
 724                 goto unlock;
 725
 726         runtime->private_data = dpcm;
 727         runtime->private_free = loopback_runtime_free;
 728         if (get_notify(dpcm))
 729                 runtime->hw = loopback_pcm_hardware;
 730         else
 731                 runtime->hw = cable->hw;
 732
 733         spin_lock_irq(&cable->lock);
 734         cable->streams[substream->stream] = dpcm;
 735         spin_unlock_irq(&cable->lock);
 736
 737  unlock:
 738         if (err < 0) {
 739                 free_cable(substream);
 740                 kfree(dpcm);
 741         }
 742         mutex_unlock(&loopback->cable_lock);
 743         return err;
 744 }
 745
 746 static int loopback_close(struct snd_pcm_substream *substream)
 747 {
 748         struct loopback *loopback = substream->private_data;
 749         struct loopback_pcm *dpcm = substream->runtime->private_data;
 750
 751         loopback_timer_stop_sync(dpcm);
 752         mutex_lock(&loopback->cable_lock);
 753         free_cable(substream);
 754         mutex_unlock(&loopback->cable_lock);
 755         return 0;
 756 }
 757
 758 static const struct snd_pcm_ops loopback_pcm_ops = {
 759         .open =         loopback_open,
 760         .close =        loopback_close,
 761         .ioctl =        snd_pcm_lib_ioctl,
 762         .hw_params =    loopback_hw_params,
 763         .hw_free =      loopback_hw_free,
 764         .prepare =      loopback_prepare,
 765         .trigger =      loopback_trigger,
 766         .pointer =      loopback_pointer,
 767 };
 768
 769 static int loopback_pcm_new(struct loopback *loopback,
 770                             int device, int substreams)
 771 {
 772         struct snd_pcm *pcm;
 773         int err;
 774
 775         err = snd_pcm_new(loopback->card, "Loopback PCM", device,
 776                           substreams, substreams, &pcm);
 777         if (err < 0)
 778                 return err;
 779         snd_pcm_set_ops(pcm, SNDRV_PCM_STREAM_PLAYBACK, &loopback_pcm_ops);
 780         snd_pcm_set_ops(pcm, SNDRV_PCM_STREAM_CAPTURE, &loopback_pcm_ops);
 781         snd_pcm_lib_preallocate_pages_for_all(pcm, SNDRV_DMA_TYPE_VMALLOC,
 782                                               NULL, 0, 0);
 783
 784         pcm->private_data = loopback;
 785         pcm->info_flags = 0;
 786         strcpy(pcm->name, "Loopback PCM");
 787
 788         loopback->pcm[device] = pcm;
 789         return 0;
 790 }
 791
 792 static int loopback_rate_shift_info(struct snd_kcontrol *kcontrol,
 793                                     struct snd_ctl_elem_info *uinfo)
 794 {
 795         uinfo->type = SNDRV_CTL_ELEM_TYPE_INTEGER;
 796         uinfo->count = 1;
 797         uinfo->value.integer.min = 80000;
 798         uinfo->value.integer.max = 120000;
 799         uinfo->value.integer.step = 1;
 800         return 0;
 801 }
 802
 803 static int loopback_rate_shift_get(struct snd_kcontrol *kcontrol,
 804                                    struct snd_ctl_elem_value *ucontrol)
 805 {
 806         struct loopback *loopback = snd_kcontrol_chip(kcontrol);
 807
 808         mutex_lock(&loopback->cable_lock);
 809         ucontrol->value.integer.value[0] =
 810                 loopback->setup[kcontrol->id.subdevice]
 811                                [kcontrol->id.device].rate_shift;
 812         mutex_unlock(&loopback->cable_lock);
 813         return 0;
 814 }
 815
 816 static int loopback_rate_shift_put(struct snd_kcontrol *kcontrol,
 817                                    struct snd_ctl_elem_value *ucontrol)
 818 {
 819         struct loopback *loopback = snd_kcontrol_chip(kcontrol);
 820         unsigned int val;
 821         int change = 0;
 822
 823         val = ucontrol->value.integer.value[0];
 824         if (val < 80000)
 825                 val = 80000;
 826         if (val > 120000)
 827                 val = 120000;
 828         mutex_lock(&loopback->cable_lock);
 829         if (val != loopback->setup[kcontrol->id.subdevice]
 830                                   [kcontrol->id.device].rate_shift) {
 831                 loopback->setup[kcontrol->id.subdevice]
 832                                [kcontrol->id.device].rate_shift = val;
 833                 change = 1;
 834         }
 835         mutex_unlock(&loopback->cable_lock);
 836         return change;
 837 }
 838
 839 static int loopback_notify_get(struct snd_kcontrol *kcontrol,
 840                                struct snd_ctl_elem_value *ucontrol)
 841 {
 842         struct loopback *loopback = snd_kcontrol_chip(kcontrol);
 843
 844         mutex_lock(&loopback->cable_lock);
 845         ucontrol->value.integer.value[0] =
 846                 loopback->setup[kcontrol->id.subdevice]
 847                                [kcontrol->id.device].notify;
 848         mutex_unlock(&loopback->cable_lock);
 849         return 0;
 850 }
 851
 852 static int loopback_notify_put(struct snd_kcontrol *kcontrol,
 853                                struct snd_ctl_elem_value *ucontrol)
 854 {
 855         struct loopback *loopback = snd_kcontrol_chip(kcontrol);
 856         unsigned int val;
 857         int change = 0;
 858
 859         val = ucontrol->value.integer.value[0] ? 1 : 0;
 860         mutex_lock(&loopback->cable_lock);
 861         if (val != loopback->setup[kcontrol->id.subdevice]
 862                                 [kcontrol->id.device].notify) {
 863                 loopback->setup[kcontrol->id.subdevice]
 864                         [kcontrol->id.device].notify = val;
 865                 change = 1;
 866         }
 867         mutex_unlock(&loopback->cable_lock);
 868         return change;
 869 }
 870
 871 static int loopback_active_get(struct snd_kcontrol *kcontrol,
 872                                struct snd_ctl_elem_value *ucontrol)
 873 {
 874         struct loopback *loopback = snd_kcontrol_chip(kcontrol);
 875         struct loopback_cable *cable;
 876
 877         unsigned int val = 0;
 878
 879         mutex_lock(&loopback->cable_lock);
 880         cable = loopback->cables[kcontrol->id.subdevice][kcontrol->id.device ^ 1];
 881         if (cable != NULL) {
 882                 unsigned int running = cable->running ^ cable->pause;
 883
 884                 val = (running & (1 << SNDRV_PCM_STREAM_PLAYBACK)) ? 1 : 0;
 885         }
 886         mutex_unlock(&loopback->cable_lock);
 887         ucontrol->value.integer.value[0] = val;
 888         return 0;
 889 }
 890
 891 static int loopback_format_info(struct snd_kcontrol *kcontrol,
 892                                 struct snd_ctl_elem_info *uinfo)
 893 {
 894         uinfo->type = SNDRV_CTL_ELEM_TYPE_INTEGER;
 895         uinfo->count = 1;
 896         uinfo->value.integer.min = 0;
 897         uinfo->value.integer.max = SNDRV_PCM_FORMAT_LAST;
 898         uinfo->value.integer.step = 1;
 899         return 0;
 900 }
 901
 902 static int loopback_format_get(struct snd_kcontrol *kcontrol,
 903                                struct snd_ctl_elem_value *ucontrol)
 904 {
 905         struct loopback *loopback = snd_kcontrol_chip(kcontrol);
 906
 907         ucontrol->value.integer.value[0] =
 908                 loopback->setup[kcontrol->id.subdevice]
 909                                [kcontrol->id.device].format;
 910         return 0;
 911 }
 912
 913 static int loopback_rate_info(struct snd_kcontrol *kcontrol,
 914                               struct snd_ctl_elem_info *uinfo)
 915 {
 916         uinfo->type = SNDRV_CTL_ELEM_TYPE_INTEGER;
 917         uinfo->count = 1;
 918         uinfo->value.integer.min = 0;
 919         uinfo->value.integer.max = 192000;
 920         uinfo->value.integer.step = 1;
 921         return 0;
 922 }
 923
 924 static int loopback_rate_get(struct snd_kcontrol *kcontrol,
 925                              struct snd_ctl_elem_value *ucontrol)
 926 {
 927         struct loopback *loopback = snd_kcontrol_chip(kcontrol);
 928
 929         mutex_lock(&loopback->cable_lock);
 930         ucontrol->value.integer.value[0] =
 931                 loopback->setup[kcontrol->id.subdevice]
 932                                [kcontrol->id.device].rate;
 933         mutex_unlock(&loopback->cable_lock);
 934         return 0;
 935 }
 936
 937 static int loopback_channels_info(struct snd_kcontrol *kcontrol,
 938                                   struct snd_ctl_elem_info *uinfo)
 939 {
 940         uinfo->type = SNDRV_CTL_ELEM_TYPE_INTEGER;
 941         uinfo->count = 1;
 942         uinfo->value.integer.min = 1;
 943         uinfo->value.integer.max = 1024;
 944         uinfo->value.integer.step = 1;
 945         return 0;
 946 }
 947
 948 static int loopback_channels_get(struct snd_kcontrol *kcontrol,
 949                                  struct snd_ctl_elem_value *ucontrol)
 950 {
 951         struct loopback *loopback = snd_kcontrol_chip(kcontrol);
 952
 953         mutex_lock(&loopback->cable_lock);
 954         ucontrol->value.integer.value[0] =
 955                 loopback->setup[kcontrol->id.subdevice]
 956                                [kcontrol->id.device].channels;
 957         mutex_unlock(&loopback->cable_lock);
 958         return 0;
 959 }
 960
 961 static struct snd_kcontrol_new loopback_controls[]  = {
 962 {
 963         .iface =        SNDRV_CTL_ELEM_IFACE_PCM,
 964         .name =         "PCM Rate Shift 100000",
 965         .info =         loopback_rate_shift_info,
 966         .get =          loopback_rate_shift_get,
 967         .put =          loopback_rate_shift_put,
 968 },
 969 {
 970         .iface =        SNDRV_CTL_ELEM_IFACE_PCM,
 971         .name =         "PCM Notify",
 972         .info =         snd_ctl_boolean_mono_info,
 973         .get =          loopback_notify_get,
 974         .put =          loopback_notify_put,
 975 },
 976 #define ACTIVE_IDX 2
 977 {
 978         .access =       SNDRV_CTL_ELEM_ACCESS_READ,
 979         .iface =        SNDRV_CTL_ELEM_IFACE_PCM,
 980         .name =         "PCM Slave Active",
 981         .info =         snd_ctl_boolean_mono_info,
 982         .get =          loopback_active_get,
 983 },
 984 #define FORMAT_IDX 3
 985 {
 986         .access =       SNDRV_CTL_ELEM_ACCESS_READ,
 987         .iface =        SNDRV_CTL_ELEM_IFACE_PCM,
 988         .name =         "PCM Slave Format",
 989         .info =         loopback_format_info,
 990         .get =          loopback_format_get
 991 },
 992 #define RATE_IDX 4
 993 {
 994         .access =       SNDRV_CTL_ELEM_ACCESS_READ,
 995         .iface =        SNDRV_CTL_ELEM_IFACE_PCM,
 996         .name =         "PCM Slave Rate",
 997         .info =         loopback_rate_info,
 998         .get =          loopback_rate_get
 999 },
1000 #define CHANNELS_IDX 5
1001 {
1002         .access =       SNDRV_CTL_ELEM_ACCESS_READ,
1003         .iface =        SNDRV_CTL_ELEM_IFACE_PCM,
1004         .name =         "PCM Slave Channels",
1005         .info =         loopback_channels_info,
1006         .get =          loopback_channels_get
1007 }
1008 };
1009
1010 static int loopback_mixer_new(struct loopback *loopback, int notify)
1011 {
1012         struct snd_card *card = loopback->card;
1013         struct snd_pcm *pcm;
1014         struct snd_kcontrol *kctl;
1015         struct loopback_setup *setup;
1016         int err, dev, substr, substr_count, idx;
1017
1018         strcpy(card->mixername, "Loopback Mixer");
1019         for (dev = 0; dev < 2; dev++) {
1020                 pcm = loopback->pcm[dev];
1021                 substr_count =
1022                     pcm->streams[SNDRV_PCM_STREAM_CAPTURE].substream_count;
1023                 for (substr = 0; substr < substr_count; substr++) {
1024                         setup = &loopback->setup[substr][dev];
1025                         setup->notify = notify;
1026                         setup->rate_shift = NO_PITCH;
1027                         setup->format = SNDRV_PCM_FORMAT_S16_LE;
1028                         setup->rate = 48000;
1029                         setup->channels = 2;
1030                         for (idx = 0; idx < ARRAY_SIZE(loopback_controls);
1031                                                                         idx++) {
1032                                 kctl = snd_ctl_new1(&loopback_controls[idx],
1033                                                     loopback);
1034                                 if (!kctl)
1035                                         return -ENOMEM;
1036                                 kctl->id.device = dev;
1037                                 kctl->id.subdevice = substr;
1038                                 switch (idx) {
1039                                 case ACTIVE_IDX:
1040                                         setup->active_id = kctl->id;
1041                                         break;
1042                                 case FORMAT_IDX:
1043                                         setup->format_id = kctl->id;
1044                                         break;
1045                                 case RATE_IDX:
1046                                         setup->rate_id = kctl->id;
1047                                         break;
1048                                 case CHANNELS_IDX:
1049                                         setup->channels_id = kctl->id;
1050                                         break;
1051                                 default:
1052                                         break;
1053                                 }
1054                                 err = snd_ctl_add(card, kctl);
1055                                 if (err < 0)
1056                                         return err;
1057                         }
1058                 }
1059         }
1060         return 0;
1061 }
1062
1063 static void print_dpcm_info(struct snd_info_buffer *buffer,
1064                             struct loopback_pcm *dpcm,
1065                             const char *id)
1066 {
1067         snd_iprintf(buffer, "  %s\n", id);
1068         if (dpcm == NULL) {
1069                 snd_iprintf(buffer, "    inactive\n");
1070                 return;
1071         }
1072         snd_iprintf(buffer, "    buffer_size:\t%u\n", dpcm->pcm_buffer_size);
1073         snd_iprintf(buffer, "    buffer_pos:\t\t%u\n", dpcm->buf_pos);
1074         snd_iprintf(buffer, "    silent_size:\t%u\n", dpcm->silent_size);
1075         snd_iprintf(buffer, "    period_size:\t%u\n", dpcm->pcm_period_size);
1076         snd_iprintf(buffer, "    bytes_per_sec:\t%u\n", dpcm->pcm_bps);
1077         snd_iprintf(buffer, "    sample_align:\t%u\n", dpcm->pcm_salign);
1078         snd_iprintf(buffer, "    rate_shift:\t\t%u\n", dpcm->pcm_rate_shift);
1079         snd_iprintf(buffer, "    update_pending:\t%u\n",
1080                                                 dpcm->period_update_pending);
1081         snd_iprintf(buffer, "    irq_pos:\t\t%u\n", dpcm->irq_pos);
1082         snd_iprintf(buffer, "    period_frac:\t%u\n", dpcm->period_size_frac);
1083         snd_iprintf(buffer, "    last_jiffies:\t%lu (%lu)\n",
1084                                         dpcm->last_jiffies, jiffies);
1085         snd_iprintf(buffer, "    timer_expires:\t%lu\n", dpcm->timer.expires);
1086 }
1087
1088 static void print_substream_info(struct snd_info_buffer *buffer,
1089                                  struct loopback *loopback,
1090                                  int sub,
1091                                  int num)
1092 {
1093         struct loopback_cable *cable = loopback->cables[sub][num];
1094
1095         snd_iprintf(buffer, "Cable %i substream %i:\n", num, sub);
1096         if (cable == NULL) {
1097                 snd_iprintf(buffer, "  inactive\n");
1098                 return;
1099         }
1100         snd_iprintf(buffer, "  valid: %u\n", cable->valid);
1101         snd_iprintf(buffer, "  running: %u\n", cable->running);
1102         snd_iprintf(buffer, "  pause: %u\n", cable->pause);
1103         print_dpcm_info(buffer, cable->streams[0], "Playback");
1104         print_dpcm_info(buffer, cable->streams[1], "Capture");
1105 }
1106
1107 static void print_cable_info(struct snd_info_entry *entry,
1108                              struct snd_info_buffer *buffer)
1109 {
1110         struct loopback *loopback = entry->private_data;
1111         int sub, num;
1112
1113         mutex_lock(&loopback->cable_lock);
1114         num = entry->name[strlen(entry->name)-1];
1115         num = num == '0' ? 0 : 1;
1116         for (sub = 0; sub < MAX_PCM_SUBSTREAMS; sub++)
1117                 print_substream_info(buffer, loopback, sub, num);
1118         mutex_unlock(&loopback->cable_lock);
1119 }
1120
1121 static int loopback_proc_new(struct loopback *loopback, int cidx)
1122 {
1123         char name[32];
1124
1125         snprintf(name, sizeof(name), "cable#%d", cidx);
1126         return snd_card_ro_proc_new(loopback->card, name, loopback,
1127                                     print_cable_info);
1128 }
1129
1130 static int loopback_probe(struct platform_device *devptr)
1131 {
1132         struct snd_card *card;
1133         struct loopback *loopback;
1134         int dev = devptr->id;
1135         int err;
1136
1137         err = snd_card_new(&devptr->dev, index[dev], id[dev], THIS_MODULE,
1138                            sizeof(struct loopback), &card);
1139         if (err < 0)
1140                 return err;
1141         loopback = card->private_data;
1142
1143         if (pcm_substreams[dev] < 1)
1144                 pcm_substreams[dev] = 1;
1145         if (pcm_substreams[dev] > MAX_PCM_SUBSTREAMS)
1146                 pcm_substreams[dev] = MAX_PCM_SUBSTREAMS;
1147
1148         loopback->card = card;
1149         mutex_init(&loopback->cable_lock);
1150
1151         err = loopback_pcm_new(loopback, 0, pcm_substreams[dev]);
1152         if (err < 0)
1153                 goto __nodev;
1154         err = loopback_pcm_new(loopback, 1, pcm_substreams[dev]);
1155         if (err < 0)
1156                 goto __nodev;
1157         err = loopback_mixer_new(loopback, pcm_notify[dev] ? 1 : 0);
1158         if (err < 0)
1159                 goto __nodev;
1160         loopback_proc_new(loopback, 0);
1161         loopback_proc_new(loopback, 1);
1162         strcpy(card->driver, "Loopback");
1163         strcpy(card->shortname, "Loopback");
1164         sprintf(card->longname, "Loopback %i", dev + 1);
1165         err = snd_card_register(card);
1166         if (!err) {
1167                 platform_set_drvdata(devptr, card);
1168                 return 0;
1169         }
1170       __nodev:
1171         snd_card_free(card);
1172         return err;
1173 }
1174
1175 static int loopback_remove(struct platform_device *devptr)
1176 {
1177         snd_card_free(platform_get_drvdata(devptr));
1178         return 0;
1179 }
1180
1181 #ifdef CONFIG_PM_SLEEP
1182 static int loopback_suspend(struct device *pdev)
1183 {
1184         struct snd_card *card = dev_get_drvdata(pdev);
1185
1186         snd_power_change_state(card, SNDRV_CTL_POWER_D3hot);
1187         return 0;
1188 }
1189
1190 static int loopback_resume(struct device *pdev)
1191 {
1192         struct snd_card *card = dev_get_drvdata(pdev);
1193
1194         snd_power_change_state(card, SNDRV_CTL_POWER_D0);
1195         return 0;
1196 }
1197
1198 static SIMPLE_DEV_PM_OPS(loopback_pm, loopback_suspend, loopback_resume);
1199 #define LOOPBACK_PM_OPS &loopback_pm
1200 #else
1201 #define LOOPBACK_PM_OPS NULL
1202 #endif
1203
1204 #define SND_LOOPBACK_DRIVER     "snd_aloop"
1205
1206 static struct platform_driver loopback_driver = {
1207         .probe          = loopback_probe,
1208         .remove         = loopback_remove,
1209         .driver         = {
1210                 .name   = SND_LOOPBACK_DRIVER,
1211                 .pm     = LOOPBACK_PM_OPS,
1212         },
1213 };
1214
1215 static void loopback_unregister_all(void)
1216 {
1217         int i;
1218
1219         for (i = 0; i < ARRAY_SIZE(devices); ++i)
1220                 platform_device_unregister(devices[i]);
1221         platform_driver_unregister(&loopback_driver);
1222 }
1223
1224 static int __init alsa_card_loopback_init(void)
1225 {
1226         int i, err, cards;
1227
1228         err = platform_driver_register(&loopback_driver);
1229         if (err < 0)
1230                 return err;
1231
1232
1233         cards = 0;
1234         for (i = 0; i < SNDRV_CARDS; i++) {
1235                 struct platform_device *device;
1236                 if (!enable[i])
1237                         continue;
1238                 device = platform_device_register_simple(SND_LOOPBACK_DRIVER,
1239                                                          i, NULL, 0);
1240                 if (IS_ERR(device))
1241                         continue;
1242                 if (!platform_get_drvdata(device)) {
1243                         platform_device_unregister(device);
1244                         continue;
1245                 }
1246                 devices[i] = device;
1247                 cards++;
1248         }
1249         if (!cards) {
1250 #ifdef MODULE
1251                 printk(KERN_ERR "aloop: No loopback enabled\n");
1252 #endif
1253                 loopback_unregister_all();
1254                 return -ENODEV;
1255         }
1256         return 0;
1257 }
1258
1259 static void __exit alsa_card_loopback_exit(void)
1260 {
1261         loopback_unregister_all();
1262 }
1263
1264 module_init(alsa_card_loopback_init)
1265 module_exit(alsa_card_loopback_exit)