sound/drivers/aloop.c

   1 /*
   2  *  Loopback soundcard
   3  *
   4  *  Original code:
   5  *  Copyright (c) by Jaroslav Kysela <perex@perex.cz>
   6  *
   7  *  More accurate positioning and full-duplex support:
   8  *  Copyright (c) Ahmet İnan <ainan at mathematik.uni-freiburg.de>
   9  *
  10  *  Major (almost complete) rewrite:
  11  *  Copyright (c) by Takashi Iwai <tiwai@suse.de>
  12  *
  13  *  A next major update in 2010 (separate timers for playback and capture):
  14  *  Copyright (c) Jaroslav Kysela <perex@perex.cz>
  15  *
  16  *   This program is free software; you can redistribute it and/or modify
  17  *   it under the terms of the GNU General Public License as published by
  18  *   the Free Software Foundation; either version 2 of the License, or
  19  *   (at your option) any later version.
  20  *
  21  *   This program is distributed in the hope that it will be useful,
  22  *   but WITHOUT ANY WARRANTY; without even the implied warranty of
  23  *   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  24  *   GNU General Public License for more details.
  25  *
  26  *   You should have received a copy of the GNU General Public License
  27  *   along with this program; if not, write to the Free Software
  28  *   Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307 USA
  29  *
  30  */
  31
  32 #include <linux/init.h>
  33 #include <linux/jiffies.h>
  34 #include <linux/slab.h>
  35 #include <linux/time.h>
  36 #include <linux/wait.h>
  37 #include <linux/moduleparam.h>
  38 #include <linux/platform_device.h>
  39 #include <sound/core.h>
  40 #include <sound/control.h>
  41 #include <sound/pcm.h>
  42 #include <sound/initval.h>
  43
  44 MODULE_AUTHOR("Jaroslav Kysela <perex@perex.cz>");
  45 MODULE_DESCRIPTION("A loopback soundcard");
  46 MODULE_LICENSE("GPL");
  47 MODULE_SUPPORTED_DEVICE("{{ALSA,Loopback soundcard}}");
  48
  49 #define MAX_PCM_SUBSTREAMS      8
  50
  51 static int index[SNDRV_CARDS] = SNDRV_DEFAULT_IDX;      /* Index 0-MAX */
  52 static char *id[SNDRV_CARDS] = SNDRV_DEFAULT_STR;       /* ID for this card */
  53 static int enable[SNDRV_CARDS] = {1, [1 ... (SNDRV_CARDS - 1)] = 0};
  54 static int pcm_substreams[SNDRV_CARDS] = {[0 ... (SNDRV_CARDS - 1)] = 8};
  55 static int pcm_notify[SNDRV_CARDS];
  56
  57 module_param_array(index, int, NULL, 0444);
  58 MODULE_PARM_DESC(index, "Index value for loopback soundcard.");
  59 module_param_array(id, charp, NULL, 0444);
  60 MODULE_PARM_DESC(id, "ID string for loopback soundcard.");
  61 module_param_array(enable, bool, NULL, 0444);
  62 MODULE_PARM_DESC(enable, "Enable this loopback soundcard.");
  63 module_param_array(pcm_substreams, int, NULL, 0444);
  64 MODULE_PARM_DESC(pcm_substreams, "PCM substreams # (1-8) for loopback driver.");
  65 module_param_array(pcm_notify, int, NULL, 0444);
  66 MODULE_PARM_DESC(pcm_notify, "Break capture when PCM format/rate/channels changes.");
  67
  68 #define NO_PITCH 100000
  69
  70 struct loopback_pcm;
  71
  72 struct loopback_cable {
  73         spinlock_t lock;
  74         struct loopback_pcm *streams[2];
  75         struct snd_pcm_hardware hw;
  76         /* flags */
  77         unsigned int valid;
  78         unsigned int running;
  79 };
  80
  81 struct loopback_setup {
  82         unsigned int notify: 1;
  83         unsigned int rate_shift;
  84         unsigned int format;
  85         unsigned int rate;
  86         unsigned int channels;
  87         struct snd_ctl_elem_id active_id;
  88         struct snd_ctl_elem_id format_id;
  89         struct snd_ctl_elem_id rate_id;
  90         struct snd_ctl_elem_id channels_id;
  91 };
  92
  93 struct loopback {
  94         struct snd_card *card;
  95         struct mutex cable_lock;
  96         struct loopback_cable *cables[MAX_PCM_SUBSTREAMS][2];
  97         struct snd_pcm *pcm[2];
  98         struct loopback_setup setup[MAX_PCM_SUBSTREAMS][2];
  99 };
 100
 101 struct loopback_pcm {
 102         struct loopback *loopback;
 103         struct snd_pcm_substream *substream;
 104         struct loopback_cable *cable;
 105         unsigned int pcm_buffer_size;
 106         unsigned int buf_pos;   /* position in buffer */
 107         unsigned int silent_size;
 108         /* PCM parameters */
 109         unsigned int pcm_period_size;
 110         unsigned int pcm_bps;           /* bytes per second */
 111         unsigned int pcm_salign;        /* bytes per sample * channels */
 112         unsigned int pcm_rate_shift;    /* rate shift value */
 113         /* flags */
 114         unsigned int period_update_pending :1;
 115         /* timer stuff */
 116         unsigned int irq_pos;           /* fractional IRQ position */
 117         unsigned int period_size_frac;
 118         unsigned long last_jiffies;
 119         struct timer_list timer;
 120 };
 121
 122 static struct platform_device *devices[SNDRV_CARDS];
 123
 124 static inline unsigned int byte_pos(struct loopback_pcm *dpcm, unsigned int x)
 125 {
 126         if (dpcm->pcm_rate_shift == NO_PITCH) {
 127                 x /= HZ;
 128         } else {
 129                 x = div_u64(NO_PITCH * (unsigned long long)x,
 130                             HZ * (unsigned long long)dpcm->pcm_rate_shift);
 131         }
 132         return x - (x % dpcm->pcm_salign);
 133 }
 134
 135 static inline unsigned int frac_pos(struct loopback_pcm *dpcm, unsigned int x)
 136 {
 137         if (dpcm->pcm_rate_shift == NO_PITCH) { /* no pitch */
 138                 return x * HZ;
 139         } else {
 140                 x = div_u64(dpcm->pcm_rate_shift * (unsigned long long)x * HZ,
 141                             NO_PITCH);
 142         }
 143         return x;
 144 }
 145
 146 static inline struct loopback_setup *get_setup(struct loopback_pcm *dpcm)
 147 {
 148         int device = dpcm->substream->pstr->pcm->device;
 149
 150         if (dpcm->substream->stream == SNDRV_PCM_STREAM_PLAYBACK)
 151                 device ^= 1;
 152         return &dpcm->loopback->setup[dpcm->substream->number][device];
 153 }
 154
 155 static inline unsigned int get_notify(struct loopback_pcm *dpcm)
 156 {
 157         return get_setup(dpcm)->notify;
 158 }
 159
 160 static inline unsigned int get_rate_shift(struct loopback_pcm *dpcm)
 161 {
 162         return get_setup(dpcm)->rate_shift;
 163 }
 164
 165 static void loopback_timer_start(struct loopback_pcm *dpcm)
 166 {
 167         unsigned long tick;
 168         unsigned int rate_shift = get_rate_shift(dpcm);
 169
 170         if (rate_shift != dpcm->pcm_rate_shift) {
 171                 dpcm->pcm_rate_shift = rate_shift;
 172                 dpcm->period_size_frac = frac_pos(dpcm, dpcm->pcm_period_size);
 173         }
 174         tick = dpcm->period_size_frac - dpcm->irq_pos;
 175         tick = (tick + dpcm->pcm_bps - 1) / dpcm->pcm_bps;
 176         dpcm->timer.expires = jiffies + tick;
 177         add_timer(&dpcm->timer);
 178 }
 179
 180 static inline void loopback_timer_stop(struct loopback_pcm *dpcm)
 181 {
 182         del_timer(&dpcm->timer);
 183 }
 184
 185 #define CABLE_VALID_PLAYBACK    (1 << SNDRV_PCM_STREAM_PLAYBACK)
 186 #define CABLE_VALID_CAPTURE     (1 << SNDRV_PCM_STREAM_CAPTURE)
 187 #define CABLE_VALID_BOTH        (CABLE_VALID_PLAYBACK|CABLE_VALID_CAPTURE)
 188
 189 static int loopback_check_format(struct loopback_cable *cable, int stream)
 190 {
 191         struct snd_pcm_runtime *runtime;
 192         struct loopback_setup *setup;
 193         struct snd_card *card;
 194         int check;
 195
 196         if (cable->valid != CABLE_VALID_BOTH) {
 197                 if (stream == SNDRV_PCM_STREAM_PLAYBACK)
 198                         goto __notify;
 199                 return 0;
 200         }
 201         runtime = cable->streams[SNDRV_PCM_STREAM_PLAYBACK]->
 202                                                         substream->runtime;
 203         check = cable->hw.formats != (1ULL << runtime->format) ||
 204                 cable->hw.rate_min != runtime->rate ||
 205                 cable->hw.rate_max != runtime->rate ||
 206                 cable->hw.channels_min != runtime->channels ||
 207                 cable->hw.channels_max != runtime->channels;
 208         if (!check)
 209                 return 0;
 210         if (stream == SNDRV_PCM_STREAM_CAPTURE) {
 211                 return -EIO;
 212         } else {
 213                 snd_pcm_stop(cable->streams[SNDRV_PCM_STREAM_CAPTURE]->
 214                                         substream, SNDRV_PCM_STATE_DRAINING);
 215               __notify:
 216                 runtime = cable->streams[SNDRV_PCM_STREAM_PLAYBACK]->
 217                                                         substream->runtime;
 218                 setup = get_setup(cable->streams[SNDRV_PCM_STREAM_PLAYBACK]);
 219                 card = cable->streams[SNDRV_PCM_STREAM_PLAYBACK]->loopback->card;
 220                 if (setup->format != runtime->format) {
 221                         snd_ctl_notify(card, SNDRV_CTL_EVENT_MASK_VALUE,
 222                                                         &setup->format_id);
 223                         setup->format = runtime->format;
 224                 }
 225                 if (setup->rate != runtime->rate) {
 226                         snd_ctl_notify(card, SNDRV_CTL_EVENT_MASK_VALUE,
 227                                                         &setup->rate_id);
 228                         setup->rate = runtime->rate;
 229                 }
 230                 if (setup->channels != runtime->channels) {
 231                         snd_ctl_notify(card, SNDRV_CTL_EVENT_MASK_VALUE,
 232                                                         &setup->channels_id);
 233                         setup->channels = runtime->channels;
 234                 }
 235         }
 236         return 0;
 237 }
 238
 239 static void loopback_active_notify(struct loopback_pcm *dpcm)
 240 {
 241         snd_ctl_notify(dpcm->loopback->card,
 242                        SNDRV_CTL_EVENT_MASK_VALUE,
 243                        &get_setup(dpcm)->active_id);
 244 }
 245
 246 static int loopback_trigger(struct snd_pcm_substream *substream, int cmd)
 247 {
 248         struct snd_pcm_runtime *runtime = substream->runtime;
 249         struct loopback_pcm *dpcm = runtime->private_data;
 250         struct loopback_cable *cable = dpcm->cable;
 251         int err;
 252
 253         switch (cmd) {
 254         case SNDRV_PCM_TRIGGER_START:
 255                 err = loopback_check_format(cable, substream->stream);
 256                 if (err < 0)
 257                         return err;
 258                 dpcm->last_jiffies = jiffies;
 259                 dpcm->pcm_rate_shift = 0;
 260                 loopback_timer_start(dpcm);
 261                 cable->running |= (1 << substream->stream);
 262                 if (substream->stream == SNDRV_PCM_STREAM_PLAYBACK)
 263                         loopback_active_notify(dpcm);
 264                 break;
 265         case SNDRV_PCM_TRIGGER_STOP:
 266                 cable->running &= ~(1 << substream->stream);
 267                 loopback_timer_stop(dpcm);
 268                 if (substream->stream == SNDRV_PCM_STREAM_PLAYBACK)
 269                         loopback_active_notify(dpcm);
 270                 break;
 271         default:
 272                 return -EINVAL;
 273         }
 274         return 0;
 275 }
 276
 277 static int loopback_prepare(struct snd_pcm_substream *substream)
 278 {
 279         struct snd_pcm_runtime *runtime = substream->runtime;
 280         struct loopback_pcm *dpcm = runtime->private_data;
 281         struct loopback_cable *cable = dpcm->cable;
 282         unsigned int bps, salign;
 283
 284         salign = (snd_pcm_format_width(runtime->format) *
 285                                                 runtime->channels) / 8;
 286         bps = salign * runtime->rate;
 287         if (bps <= 0 || salign <= 0)
 288                 return -EINVAL;
 289
 290         dpcm->buf_pos = 0;
 291         dpcm->pcm_buffer_size = frames_to_bytes(runtime, runtime->buffer_size);
 292         if (substream->stream == SNDRV_PCM_STREAM_CAPTURE) {
 293                 /* clear capture buffer */
 294                 dpcm->silent_size = dpcm->pcm_buffer_size;
 295                 snd_pcm_format_set_silence(runtime->format, runtime->dma_area,
 296                                            runtime->buffer_size * runtime->channels);
 297         }
 298
 299         dpcm->irq_pos = 0;
 300         dpcm->period_update_pending = 0;
 301         dpcm->pcm_bps = bps;
 302         dpcm->pcm_salign = salign;
 303         dpcm->pcm_period_size = frames_to_bytes(runtime, runtime->period_size);
 304
 305         mutex_lock(&dpcm->loopback->cable_lock);
 306         if (!(cable->valid & ~(1 << substream->stream))) {
 307                 cable->hw.formats = (1ULL << runtime->format);
 308                 cable->hw.rate_min = runtime->rate;
 309                 cable->hw.rate_max = runtime->rate;
 310                 cable->hw.channels_min = runtime->channels;
 311                 cable->hw.channels_max = runtime->channels;
 312         }
 313         cable->valid |= 1 << substream->stream;
 314         mutex_unlock(&dpcm->loopback->cable_lock);
 315
 316         return 0;
 317 }
 318
 319 static void clear_capture_buf(struct loopback_pcm *dpcm, unsigned int bytes)
 320 {
 321         struct snd_pcm_runtime *runtime = dpcm->substream->runtime;
 322         char *dst = runtime->dma_area;
 323         unsigned int dst_off = dpcm->buf_pos;
 324
 325         if (dpcm->silent_size >= dpcm->pcm_buffer_size)
 326                 return;
 327         if (dpcm->silent_size + bytes > dpcm->pcm_buffer_size)
 328                 bytes = dpcm->pcm_buffer_size - dpcm->silent_size;
 329
 330         for (;;) {
 331                 unsigned int size = bytes;
 332                 if (dst_off + size > dpcm->pcm_buffer_size)
 333                         size = dpcm->pcm_buffer_size - dst_off;
 334                 snd_pcm_format_set_silence(runtime->format, dst + dst_off,
 335                                            bytes_to_frames(runtime, size) *
 336                                                 runtime->channels);
 337                 dpcm->silent_size += size;
 338                 bytes -= size;
 339                 if (!bytes)
 340                         break;
 341                 dst_off = 0;
 342         }
 343 }
 344
 345 static void copy_play_buf(struct loopback_pcm *play,
 346                           struct loopback_pcm *capt,
 347                           unsigned int bytes)
 348 {
 349         struct snd_pcm_runtime *runtime = play->substream->runtime;
 350         char *src = play->substream->runtime->dma_area;
 351         char *dst = capt->substream->runtime->dma_area;
 352         unsigned int src_off = play->buf_pos;
 353         unsigned int dst_off = capt->buf_pos;
 354         unsigned int clear_bytes = 0;
 355
 356         /* check if playback is draining, trim the capture copy size
 357          * when our pointer is at the end of playback ring buffer */
 358         if (runtime->status->state == SNDRV_PCM_STATE_DRAINING &&
 359             snd_pcm_playback_hw_avail(runtime) < runtime->buffer_size) {
 360                 snd_pcm_uframes_t appl_ptr, appl_ptr1, diff;
 361                 appl_ptr = appl_ptr1 = runtime->control->appl_ptr;
 362                 appl_ptr1 -= appl_ptr1 % runtime->buffer_size;
 363                 appl_ptr1 += play->buf_pos / play->pcm_salign;
 364                 if (appl_ptr < appl_ptr1)
 365                         appl_ptr1 -= runtime->buffer_size;
 366                 diff = (appl_ptr - appl_ptr1) * play->pcm_salign;
 367                 if (diff < bytes) {
 368                         clear_bytes = bytes - diff;
 369                         bytes = diff;
 370                 }
 371         }
 372
 373         for (;;) {
 374                 unsigned int size = bytes;
 375                 if (src_off + size > play->pcm_buffer_size)
 376                         size = play->pcm_buffer_size - src_off;
 377                 if (dst_off + size > capt->pcm_buffer_size)
 378                         size = capt->pcm_buffer_size - dst_off;
 379                 memcpy(dst + dst_off, src + src_off, size);
 380                 capt->silent_size = 0;
 381                 bytes -= size;
 382                 if (!bytes)
 383                         break;
 384                 src_off = (src_off + size) % play->pcm_buffer_size;
 385                 dst_off = (dst_off + size) % capt->pcm_buffer_size;
 386         }
 387
 388         if (clear_bytes > 0)
 389                 clear_capture_buf(capt, clear_bytes);
 390 }
 391
 392 #define BYTEPOS_UPDATE_POSONLY  0
 393 #define BYTEPOS_UPDATE_CLEAR    1
 394 #define BYTEPOS_UPDATE_COPY     2
 395
 396 static void loopback_bytepos_update(struct loopback_pcm *dpcm,
 397                                     unsigned int delta,
 398                                     unsigned int cmd)
 399 {
 400         unsigned int count;
 401         unsigned long last_pos;
 402
 403         last_pos = byte_pos(dpcm, dpcm->irq_pos);
 404         dpcm->irq_pos += delta * dpcm->pcm_bps;
 405         count = byte_pos(dpcm, dpcm->irq_pos) - last_pos;
 406         if (!count)
 407                 return;
 408         if (cmd == BYTEPOS_UPDATE_CLEAR)
 409                 clear_capture_buf(dpcm, count);
 410         else if (cmd == BYTEPOS_UPDATE_COPY)
 411                 copy_play_buf(dpcm->cable->streams[SNDRV_PCM_STREAM_PLAYBACK],
 412                               dpcm->cable->streams[SNDRV_PCM_STREAM_CAPTURE],
 413                               count);
 414         dpcm->buf_pos += count;
 415         dpcm->buf_pos %= dpcm->pcm_buffer_size;
 416         if (dpcm->irq_pos >= dpcm->period_size_frac) {
 417                 dpcm->irq_pos %= dpcm->period_size_frac;
 418                 dpcm->period_update_pending = 1;
 419         }
 420 }
 421
 422 static void loopback_pos_update(struct loopback_cable *cable)
 423 {
 424         struct loopback_pcm *dpcm_play =
 425                         cable->streams[SNDRV_PCM_STREAM_PLAYBACK];
 426         struct loopback_pcm *dpcm_capt =
 427                         cable->streams[SNDRV_PCM_STREAM_CAPTURE];
 428         unsigned long delta_play = 0, delta_capt = 0;
 429
 430         spin_lock(&cable->lock);
 431         if (cable->running & (1 << SNDRV_PCM_STREAM_PLAYBACK)) {
 432                 delta_play = jiffies - dpcm_play->last_jiffies;
 433                 dpcm_play->last_jiffies += delta_play;
 434         }
 435
 436         if (cable->running & (1 << SNDRV_PCM_STREAM_CAPTURE)) {
 437                 delta_capt = jiffies - dpcm_capt->last_jiffies;
 438                 dpcm_capt->last_jiffies += delta_capt;
 439         }
 440
 441         if (delta_play == 0 && delta_capt == 0) {
 442                 spin_unlock(&cable->lock);
 443                 return;
 444         }
 445
 446         if (delta_play > delta_capt) {
 447                 loopback_bytepos_update(dpcm_play, delta_play - delta_capt,
 448                                         BYTEPOS_UPDATE_POSONLY);
 449                 delta_play = delta_capt;
 450         } else if (delta_play < delta_capt) {
 451                 loopback_bytepos_update(dpcm_capt, delta_capt - delta_play,
 452                                         BYTEPOS_UPDATE_CLEAR);
 453                 delta_capt = delta_play;
 454         }
 455
 456         if (delta_play == 0 && delta_capt == 0) {
 457                 spin_unlock(&cable->lock);
 458                 return;
 459         }
 460         /* note delta_capt == delta_play at this moment */
 461         loopback_bytepos_update(dpcm_capt, delta_capt, BYTEPOS_UPDATE_COPY);
 462         loopback_bytepos_update(dpcm_play, delta_play, BYTEPOS_UPDATE_POSONLY);
 463         spin_unlock(&cable->lock);
 464 }
 465
 466 static void loopback_timer_function(unsigned long data)
 467 {
 468         struct loopback_pcm *dpcm = (struct loopback_pcm *)data;
 469         int stream;
 470
 471         loopback_pos_update(dpcm->cable);
 472         stream = dpcm->substream->stream;
 473         if (dpcm->cable->running & (1 << stream))
 474                 loopback_timer_start(dpcm);
 475         if (dpcm->period_update_pending) {
 476                 dpcm->period_update_pending = 0;
 477                 if (dpcm->cable->running & (1 << stream))
 478                         snd_pcm_period_elapsed(dpcm->substream);
 479         }
 480 }
 481
 482 static snd_pcm_uframes_t loopback_pointer(struct snd_pcm_substream *substream)
 483 {
 484         struct snd_pcm_runtime *runtime = substream->runtime;
 485         struct loopback_pcm *dpcm = runtime->private_data;
 486
 487         loopback_pos_update(dpcm->cable);
 488         return bytes_to_frames(runtime, dpcm->buf_pos);
 489 }
 490
 491 static struct snd_pcm_hardware loopback_pcm_hardware =
 492 {
 493         .info =         (SNDRV_PCM_INFO_INTERLEAVED | SNDRV_PCM_INFO_MMAP |
 494                          SNDRV_PCM_INFO_MMAP_VALID),
 495         .formats =      (SNDRV_PCM_FMTBIT_S16_LE | SNDRV_PCM_FMTBIT_S16_BE |
 496                          SNDRV_PCM_FMTBIT_S32_LE | SNDRV_PCM_FMTBIT_S32_BE |
 497                          SNDRV_PCM_FMTBIT_FLOAT_LE | SNDRV_PCM_FMTBIT_FLOAT_BE),
 498         .rates =        SNDRV_PCM_RATE_CONTINUOUS | SNDRV_PCM_RATE_8000_192000,
 499         .rate_min =             8000,
 500         .rate_max =             192000,
 501         .channels_min =         1,
 502         .channels_max =         32,
 503         .buffer_bytes_max =     2 * 1024 * 1024,
 504         .period_bytes_min =     64,
 505         .period_bytes_max =     2 * 1024 * 1024,
 506         .periods_min =          1,
 507         .periods_max =          1024,
 508         .fifo_size =            0,
 509 };
 510
 511 static void loopback_runtime_free(struct snd_pcm_runtime *runtime)
 512 {
 513         struct loopback_pcm *dpcm = runtime->private_data;
 514         kfree(dpcm);
 515 }
 516
 517 static int loopback_hw_params(struct snd_pcm_substream *substream,
 518                               struct snd_pcm_hw_params *params)
 519 {
 520         return snd_pcm_lib_malloc_pages(substream, params_buffer_bytes(params));
 521 }
 522
 523 static int loopback_hw_free(struct snd_pcm_substream *substream)
 524 {
 525         struct snd_pcm_runtime *runtime = substream->runtime;
 526         struct loopback_pcm *dpcm = runtime->private_data;
 527         struct loopback_cable *cable = dpcm->cable;
 528
 529         mutex_lock(&dpcm->loopback->cable_lock);
 530         cable->valid &= ~(1 << substream->stream);
 531         mutex_unlock(&dpcm->loopback->cable_lock);
 532         return snd_pcm_lib_free_pages(substream);
 533 }
 534
 535 static unsigned int get_cable_index(struct snd_pcm_substream *substream)
 536 {
 537         if (!substream->pcm->device)
 538                 return substream->stream;
 539         else
 540                 return !substream->stream;
 541 }
 542
 543 static int loopback_open(struct snd_pcm_substream *substream)
 544 {
 545         struct snd_pcm_runtime *runtime = substream->runtime;
 546         struct loopback *loopback = substream->private_data;
 547         struct loopback_pcm *dpcm;
 548         struct loopback_cable *cable;
 549         int err = 0;
 550         int dev = get_cable_index(substream);
 551
 552         mutex_lock(&loopback->cable_lock);
 553         dpcm = kzalloc(sizeof(*dpcm), GFP_KERNEL);
 554         if (!dpcm) {
 555                 err = -ENOMEM;
 556                 goto unlock;
 557         }
 558         dpcm->loopback = loopback;
 559         dpcm->substream = substream;
 560         setup_timer(&dpcm->timer, loopback_timer_function,
 561                     (unsigned long)dpcm);
 562
 563         cable = loopback->cables[substream->number][dev];
 564         if (!cable) {
 565                 cable = kzalloc(sizeof(*cable), GFP_KERNEL);
 566                 if (!cable) {
 567                         kfree(dpcm);
 568                         err = -ENOMEM;
 569                         goto unlock;
 570                 }
 571                 spin_lock_init(&cable->lock);
 572                 cable->hw = loopback_pcm_hardware;
 573                 loopback->cables[substream->number][dev] = cable;
 574         }
 575         dpcm->cable = cable;
 576         cable->streams[substream->stream] = dpcm;
 577
 578         snd_pcm_hw_constraint_integer(runtime, SNDRV_PCM_HW_PARAM_PERIODS);
 579
 580         runtime->private_data = dpcm;
 581         runtime->private_free = loopback_runtime_free;
 582         if (get_notify(dpcm) &&
 583             substream->stream == SNDRV_PCM_STREAM_PLAYBACK) {
 584                 runtime->hw = loopback_pcm_hardware;
 585         } else {
 586                 runtime->hw = cable->hw;
 587         }
 588  unlock:
 589         mutex_unlock(&loopback->cable_lock);
 590         return err;
 591 }
 592
 593 static int loopback_close(struct snd_pcm_substream *substream)
 594 {
 595         struct loopback *loopback = substream->private_data;
 596         struct loopback_pcm *dpcm = substream->runtime->private_data;
 597         struct loopback_cable *cable;
 598         int dev = get_cable_index(substream);
 599
 600         loopback_timer_stop(dpcm);
 601         mutex_lock(&loopback->cable_lock);
 602         cable = loopback->cables[substream->number][dev];
 603         if (cable->streams[!substream->stream]) {
 604                 /* other stream is still alive */
 605                 cable->streams[substream->stream] = NULL;
 606         } else {
 607                 /* free the cable */
 608                 loopback->cables[substream->number][dev] = NULL;
 609                 kfree(cable);
 610         }
 611         mutex_unlock(&loopback->cable_lock);
 612         return 0;
 613 }
 614
 615 static struct snd_pcm_ops loopback_playback_ops = {
 616         .open =         loopback_open,
 617         .close =        loopback_close,
 618         .ioctl =        snd_pcm_lib_ioctl,
 619         .hw_params =    loopback_hw_params,
 620         .hw_free =      loopback_hw_free,
 621         .prepare =      loopback_prepare,
 622         .trigger =      loopback_trigger,
 623         .pointer =      loopback_pointer,
 624 };
 625
 626 static struct snd_pcm_ops loopback_capture_ops = {
 627         .open =         loopback_open,
 628         .close =        loopback_close,
 629         .ioctl =        snd_pcm_lib_ioctl,
 630         .hw_params =    loopback_hw_params,
 631         .hw_free =      loopback_hw_free,
 632         .prepare =      loopback_prepare,
 633         .trigger =      loopback_trigger,
 634         .pointer =      loopback_pointer,
 635 };
 636
 637 static int __devinit loopback_pcm_new(struct loopback *loopback,
 638                                       int device, int substreams)
 639 {
 640         struct snd_pcm *pcm;
 641         int err;
 642
 643         err = snd_pcm_new(loopback->card, "Loopback PCM", device,
 644                           substreams, substreams, &pcm);
 645         if (err < 0)
 646                 return err;
 647         snd_pcm_set_ops(pcm, SNDRV_PCM_STREAM_PLAYBACK, &loopback_playback_ops);
 648         snd_pcm_set_ops(pcm, SNDRV_PCM_STREAM_CAPTURE, &loopback_capture_ops);
 649
 650         pcm->private_data = loopback;
 651         pcm->info_flags = 0;
 652         strcpy(pcm->name, "Loopback PCM");
 653
 654         loopback->pcm[device] = pcm;
 655
 656         snd_pcm_lib_preallocate_pages_for_all(pcm, SNDRV_DMA_TYPE_CONTINUOUS,
 657                         snd_dma_continuous_data(GFP_KERNEL),
 658                         0, 2 * 1024 * 1024);
 659         return 0;
 660 }
 661
 662 static int loopback_rate_shift_info(struct snd_kcontrol *kcontrol,
 663                                     struct snd_ctl_elem_info *uinfo)
 664 {
 665         uinfo->type = SNDRV_CTL_ELEM_TYPE_INTEGER;
 666         uinfo->count = 1;
 667         uinfo->value.integer.min = 80000;
 668         uinfo->value.integer.max = 120000;
 669         uinfo->value.integer.step = 1;
 670         return 0;
 671 }
 672
 673 static int loopback_rate_shift_get(struct snd_kcontrol *kcontrol,
 674                                    struct snd_ctl_elem_value *ucontrol)
 675 {
 676         struct loopback *loopback = snd_kcontrol_chip(kcontrol);
 677
 678         ucontrol->value.integer.value[0] =
 679                 loopback->setup[kcontrol->id.subdevice]
 680                                [kcontrol->id.device].rate_shift;
 681         return 0;
 682 }
 683
 684 static int loopback_rate_shift_put(struct snd_kcontrol *kcontrol,
 685                                    struct snd_ctl_elem_value *ucontrol)
 686 {
 687         struct loopback *loopback = snd_kcontrol_chip(kcontrol);
 688         unsigned int val;
 689         int change = 0;
 690
 691         val = ucontrol->value.integer.value[0];
 692         if (val < 80000)
 693                 val = 80000;
 694         if (val > 120000)
 695                 val = 120000;
 696         mutex_lock(&loopback->cable_lock);
 697         if (val != loopback->setup[kcontrol->id.subdevice]
 698                                   [kcontrol->id.device].rate_shift) {
 699                 loopback->setup[kcontrol->id.subdevice]
 700                                [kcontrol->id.device].rate_shift = val;
 701                 change = 1;
 702         }
 703         mutex_unlock(&loopback->cable_lock);
 704         return change;
 705 }
 706
 707 static int loopback_notify_get(struct snd_kcontrol *kcontrol,
 708                                struct snd_ctl_elem_value *ucontrol)
 709 {
 710         struct loopback *loopback = snd_kcontrol_chip(kcontrol);
 711
 712         ucontrol->value.integer.value[0] =
 713                 loopback->setup[kcontrol->id.subdevice]
 714                                [kcontrol->id.device].notify;
 715         return 0;
 716 }
 717
 718 static int loopback_notify_put(struct snd_kcontrol *kcontrol,
 719                                struct snd_ctl_elem_value *ucontrol)
 720 {
 721         struct loopback *loopback = snd_kcontrol_chip(kcontrol);
 722         unsigned int val;
 723         int change = 0;
 724
 725         val = ucontrol->value.integer.value[0] ? 1 : 0;
 726         if (val != loopback->setup[kcontrol->id.subdevice]
 727                                 [kcontrol->id.device].notify) {
 728                 loopback->setup[kcontrol->id.subdevice]
 729                         [kcontrol->id.device].notify = val;
 730                 change = 1;
 731         }
 732         return change;
 733 }
 734
 735 static int loopback_active_get(struct snd_kcontrol *kcontrol,
 736                                struct snd_ctl_elem_value *ucontrol)
 737 {
 738         struct loopback *loopback = snd_kcontrol_chip(kcontrol);
 739         struct loopback_cable *cable = loopback->cables
 740                                 [kcontrol->id.subdevice][kcontrol->id.device];
 741         unsigned int val = 0;
 742
 743         if (cable != NULL)
 744                 val = (cable->running & (1 << SNDRV_PCM_STREAM_PLAYBACK)) ?
 745                                                                         1 : 0;
 746         ucontrol->value.integer.value[0] = val;
 747         return 0;
 748 }
 749
 750 static int loopback_format_info(struct snd_kcontrol *kcontrol,
 751                                 struct snd_ctl_elem_info *uinfo)
 752 {
 753         uinfo->type = SNDRV_CTL_ELEM_TYPE_INTEGER;
 754         uinfo->count = 1;
 755         uinfo->value.integer.min = 0;
 756         uinfo->value.integer.max = SNDRV_PCM_FORMAT_LAST;
 757         uinfo->value.integer.step = 1;
 758         return 0;
 759 }
 760
 761 static int loopback_format_get(struct snd_kcontrol *kcontrol,
 762                                struct snd_ctl_elem_value *ucontrol)
 763 {
 764         struct loopback *loopback = snd_kcontrol_chip(kcontrol);
 765
 766         ucontrol->value.integer.value[0] =
 767                 loopback->setup[kcontrol->id.subdevice]
 768                                [kcontrol->id.device].format;
 769         return 0;
 770 }
 771
 772 static int loopback_rate_info(struct snd_kcontrol *kcontrol,
 773                               struct snd_ctl_elem_info *uinfo)
 774 {
 775         uinfo->type = SNDRV_CTL_ELEM_TYPE_INTEGER;
 776         uinfo->count = 1;
 777         uinfo->value.integer.min = 0;
 778         uinfo->value.integer.max = 192000;
 779         uinfo->value.integer.step = 1;
 780         return 0;
 781 }
 782
 783 static int loopback_rate_get(struct snd_kcontrol *kcontrol,
 784                              struct snd_ctl_elem_value *ucontrol)
 785 {
 786         struct loopback *loopback = snd_kcontrol_chip(kcontrol);
 787
 788         ucontrol->value.integer.value[0] =
 789                 loopback->setup[kcontrol->id.subdevice]
 790                                [kcontrol->id.device].rate;
 791         return 0;
 792 }
 793
 794 static int loopback_channels_info(struct snd_kcontrol *kcontrol,
 795                                   struct snd_ctl_elem_info *uinfo)
 796 {
 797         uinfo->type = SNDRV_CTL_ELEM_TYPE_INTEGER;
 798         uinfo->count = 1;
 799         uinfo->value.integer.min = 1;
 800         uinfo->value.integer.max = 1024;
 801         uinfo->value.integer.step = 1;
 802         return 0;
 803 }
 804
 805 static int loopback_channels_get(struct snd_kcontrol *kcontrol,
 806                                  struct snd_ctl_elem_value *ucontrol)
 807 {
 808         struct loopback *loopback = snd_kcontrol_chip(kcontrol);
 809
 810         ucontrol->value.integer.value[0] =
 811                 loopback->setup[kcontrol->id.subdevice]
 812                                [kcontrol->id.device].channels;
 813         return 0;
 814 }
 815
 816 static struct snd_kcontrol_new loopback_controls[]  __devinitdata = {
 817 {
 818         .iface =        SNDRV_CTL_ELEM_IFACE_PCM,
 819         .name =         "PCM Rate Shift 100000",
 820         .info =         loopback_rate_shift_info,
 821         .get =          loopback_rate_shift_get,
 822         .put =          loopback_rate_shift_put,
 823 },
 824 {
 825         .iface =        SNDRV_CTL_ELEM_IFACE_PCM,
 826         .name =         "PCM Notify",
 827         .info =         snd_ctl_boolean_mono_info,
 828         .get =          loopback_notify_get,
 829         .put =          loopback_notify_put,
 830 },
 831 #define ACTIVE_IDX 2
 832 {
 833         .access =       SNDRV_CTL_ELEM_ACCESS_READ,
 834         .iface =        SNDRV_CTL_ELEM_IFACE_PCM,
 835         .name =         "PCM Slave Active",
 836         .info =         snd_ctl_boolean_mono_info,
 837         .get =          loopback_active_get,
 838 },
 839 #define FORMAT_IDX 3
 840 {
 841         .access =       SNDRV_CTL_ELEM_ACCESS_READ,
 842         .iface =        SNDRV_CTL_ELEM_IFACE_PCM,
 843         .name =         "PCM Slave Format",
 844         .info =         loopback_format_info,
 845         .get =          loopback_format_get
 846 },
 847 #define RATE_IDX 4
 848 {
 849         .access =       SNDRV_CTL_ELEM_ACCESS_READ,
 850         .iface =        SNDRV_CTL_ELEM_IFACE_PCM,
 851         .name =         "PCM Slave Rate",
 852         .info =         loopback_rate_info,
 853         .get =          loopback_rate_get
 854 },
 855 #define CHANNELS_IDX 5
 856 {
 857         .access =       SNDRV_CTL_ELEM_ACCESS_READ,
 858         .iface =        SNDRV_CTL_ELEM_IFACE_PCM,
 859         .name =         "PCM Slave Channels",
 860         .info =         loopback_channels_info,
 861         .get =          loopback_channels_get
 862 }
 863 };
 864
 865 static int __devinit loopback_mixer_new(struct loopback *loopback, int notify)
 866 {
 867         struct snd_card *card = loopback->card;
 868         struct snd_pcm *pcm;
 869         struct snd_kcontrol *kctl;
 870         struct loopback_setup *setup;
 871         int err, dev, substr, substr_count, idx;
 872
 873         strcpy(card->mixername, "Loopback Mixer");
 874         for (dev = 0; dev < 2; dev++) {
 875                 pcm = loopback->pcm[dev];
 876                 substr_count =
 877                     pcm->streams[SNDRV_PCM_STREAM_CAPTURE].substream_count;
 878                 for (substr = 0; substr < substr_count; substr++) {
 879                         setup = &loopback->setup[substr][dev];
 880                         setup->notify = notify;
 881                         setup->rate_shift = NO_PITCH;
 882                         setup->format = SNDRV_PCM_FORMAT_S16_LE;
 883                         setup->rate = 48000;
 884                         setup->channels = 2;
 885                         for (idx = 0; idx < ARRAY_SIZE(loopback_controls);
 886                                                                         idx++) {
 887                                 kctl = snd_ctl_new1(&loopback_controls[idx],
 888                                                     loopback);
 889                                 if (!kctl)
 890                                         return -ENOMEM;
 891                                 kctl->id.device = dev;
 892                                 kctl->id.subdevice = substr;
 893                                 switch (idx) {
 894                                 case ACTIVE_IDX:
 895                                         setup->active_id = kctl->id;
 896                                         break;
 897                                 case FORMAT_IDX:
 898                                         setup->format_id = kctl->id;
 899                                         break;
 900                                 case RATE_IDX:
 901                                         setup->rate_id = kctl->id;
 902                                         break;
 903                                 case CHANNELS_IDX:
 904                                         setup->channels_id = kctl->id;
 905                                         break;
 906                                 default:
 907                                         break;
 908                                 }
 909                                 err = snd_ctl_add(card, kctl);
 910                                 if (err < 0)
 911                                         return err;
 912                         }
 913                 }
 914         }
 915         return 0;
 916 }
 917
 918 static int __devinit loopback_probe(struct platform_device *devptr)
 919 {
 920         struct snd_card *card;
 921         struct loopback *loopback;
 922         int dev = devptr->id;
 923         int err;
 924
 925         err = snd_card_create(index[dev], id[dev], THIS_MODULE,
 926                               sizeof(struct loopback), &card);
 927         if (err < 0)
 928                 return err;
 929         loopback = card->private_data;
 930
 931         if (pcm_substreams[dev] < 1)
 932                 pcm_substreams[dev] = 1;
 933         if (pcm_substreams[dev] > MAX_PCM_SUBSTREAMS)
 934                 pcm_substreams[dev] = MAX_PCM_SUBSTREAMS;
 935
 936         loopback->card = card;
 937         mutex_init(&loopback->cable_lock);
 938
 939         err = loopback_pcm_new(loopback, 0, pcm_substreams[dev]);
 940         if (err < 0)
 941                 goto __nodev;
 942         err = loopback_pcm_new(loopback, 1, pcm_substreams[dev]);
 943         if (err < 0)
 944                 goto __nodev;
 945         err = loopback_mixer_new(loopback, pcm_notify[dev] ? 1 : 0);
 946         if (err < 0)
 947                 goto __nodev;
 948         strcpy(card->driver, "Loopback");
 949         strcpy(card->shortname, "Loopback");
 950         sprintf(card->longname, "Loopback %i", dev + 1);
 951         err = snd_card_register(card);
 952         if (!err) {
 953                 platform_set_drvdata(devptr, card);
 954                 return 0;
 955         }
 956       __nodev:
 957         snd_card_free(card);
 958         return err;
 959 }
 960
 961 static int __devexit loopback_remove(struct platform_device *devptr)
 962 {
 963         snd_card_free(platform_get_drvdata(devptr));
 964         platform_set_drvdata(devptr, NULL);
 965         return 0;
 966 }
 967
 968 #ifdef CONFIG_PM
 969 static int loopback_suspend(struct platform_device *pdev,
 970                                 pm_message_t state)
 971 {
 972         struct snd_card *card = platform_get_drvdata(pdev);
 973         struct loopback *loopback = card->private_data;
 974
 975         snd_power_change_state(card, SNDRV_CTL_POWER_D3hot);
 976
 977         snd_pcm_suspend_all(loopback->pcm[0]);
 978         snd_pcm_suspend_all(loopback->pcm[1]);
 979         return 0;
 980 }
 981
 982 static int loopback_resume(struct platform_device *pdev)
 983 {
 984         struct snd_card *card = platform_get_drvdata(pdev);
 985
 986         snd_power_change_state(card, SNDRV_CTL_POWER_D0);
 987         return 0;
 988 }
 989 #endif
 990
 991 #define SND_LOOPBACK_DRIVER     "snd_aloop"
 992
 993 static struct platform_driver loopback_driver = {
 994         .probe          = loopback_probe,
 995         .remove         = __devexit_p(loopback_remove),
 996 #ifdef CONFIG_PM
 997         .suspend        = loopback_suspend,
 998         .resume         = loopback_resume,
 999 #endif
1000         .driver         = {
1001                 .name   = SND_LOOPBACK_DRIVER
1002         },
1003 };
1004
1005 static void loopback_unregister_all(void)
1006 {
1007         int i;
1008
1009         for (i = 0; i < ARRAY_SIZE(devices); ++i)
1010                 platform_device_unregister(devices[i]);
1011         platform_driver_unregister(&loopback_driver);
1012 }
1013
1014 static int __init alsa_card_loopback_init(void)
1015 {
1016         int i, err, cards;
1017
1018         err = platform_driver_register(&loopback_driver);
1019         if (err < 0)
1020                 return err;
1021
1022
1023         cards = 0;
1024         for (i = 0; i < SNDRV_CARDS; i++) {
1025                 struct platform_device *device;
1026                 if (!enable[i])
1027                         continue;
1028                 device = platform_device_register_simple(SND_LOOPBACK_DRIVER,
1029                                                          i, NULL, 0);
1030                 if (IS_ERR(device))
1031                         continue;
1032                 if (!platform_get_drvdata(device)) {
1033                         platform_device_unregister(device);
1034                         continue;
1035                 }
1036                 devices[i] = device;
1037                 cards++;
1038         }
1039         if (!cards) {
1040 #ifdef MODULE
1041                 printk(KERN_ERR "aloop: No loopback enabled\n");
1042 #endif
1043                 loopback_unregister_all();
1044                 return -ENODEV;
1045         }
1046         return 0;
1047 }
1048
1049 static void __exit alsa_card_loopback_exit(void)
1050 {
1051         loopback_unregister_all();
1052 }
1053
1054 module_init(alsa_card_loopback_init)
1055 module_exit(alsa_card_loopback_exit)