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 = 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                 capt->silent_size = 0;
 391         }
 392 }
 393
 394 #define BYTEPOS_UPDATE_POSONLY  0
 395 #define BYTEPOS_UPDATE_CLEAR    1
 396 #define BYTEPOS_UPDATE_COPY     2
 397
 398 static void loopback_bytepos_update(struct loopback_pcm *dpcm,
 399                                     unsigned int delta,
 400                                     unsigned int cmd)
 401 {
 402         unsigned int count;
 403         unsigned long last_pos;
 404
 405         last_pos = byte_pos(dpcm, dpcm->irq_pos);
 406         dpcm->irq_pos += delta * dpcm->pcm_bps;
 407         count = byte_pos(dpcm, dpcm->irq_pos) - last_pos;
 408         if (!count)
 409                 return;
 410         if (cmd == BYTEPOS_UPDATE_CLEAR)
 411                 clear_capture_buf(dpcm, count);
 412         else if (cmd == BYTEPOS_UPDATE_COPY)
 413                 copy_play_buf(dpcm->cable->streams[SNDRV_PCM_STREAM_PLAYBACK],
 414                               dpcm->cable->streams[SNDRV_PCM_STREAM_CAPTURE],
 415                               count);
 416         dpcm->buf_pos += count;
 417         dpcm->buf_pos %= dpcm->pcm_buffer_size;
 418         if (dpcm->irq_pos >= dpcm->period_size_frac) {
 419                 dpcm->irq_pos %= dpcm->period_size_frac;
 420                 dpcm->period_update_pending = 1;
 421         }
 422 }
 423
 424 static void loopback_pos_update(struct loopback_cable *cable)
 425 {
 426         struct loopback_pcm *dpcm_play =
 427                         cable->streams[SNDRV_PCM_STREAM_PLAYBACK];
 428         struct loopback_pcm *dpcm_capt =
 429                         cable->streams[SNDRV_PCM_STREAM_CAPTURE];
 430         unsigned long delta_play = 0, delta_capt = 0;
 431
 432         spin_lock(&cable->lock);
 433         if (cable->running & (1 << SNDRV_PCM_STREAM_PLAYBACK)) {
 434                 delta_play = jiffies - dpcm_play->last_jiffies;
 435                 dpcm_play->last_jiffies += delta_play;
 436         }
 437
 438         if (cable->running & (1 << SNDRV_PCM_STREAM_CAPTURE)) {
 439                 delta_capt = jiffies - dpcm_capt->last_jiffies;
 440                 dpcm_capt->last_jiffies += delta_capt;
 441         }
 442
 443         if (delta_play == 0 && delta_capt == 0) {
 444                 spin_unlock(&cable->lock);
 445                 return;
 446         }
 447
 448         if (delta_play > delta_capt) {
 449                 loopback_bytepos_update(dpcm_play, delta_play - delta_capt,
 450                                         BYTEPOS_UPDATE_POSONLY);
 451                 delta_play = delta_capt;
 452         } else if (delta_play < delta_capt) {
 453                 loopback_bytepos_update(dpcm_capt, delta_capt - delta_play,
 454                                         BYTEPOS_UPDATE_CLEAR);
 455                 delta_capt = delta_play;
 456         }
 457
 458         if (delta_play == 0 && delta_capt == 0) {
 459                 spin_unlock(&cable->lock);
 460                 return;
 461         }
 462         /* note delta_capt == delta_play at this moment */
 463         loopback_bytepos_update(dpcm_capt, delta_capt, BYTEPOS_UPDATE_COPY);
 464         loopback_bytepos_update(dpcm_play, delta_play, BYTEPOS_UPDATE_POSONLY);
 465         spin_unlock(&cable->lock);
 466 }
 467
 468 static void loopback_timer_function(unsigned long data)
 469 {
 470         struct loopback_pcm *dpcm = (struct loopback_pcm *)data;
 471         int stream;
 472
 473         loopback_pos_update(dpcm->cable);
 474         stream = dpcm->substream->stream;
 475         if (dpcm->cable->running & (1 << stream))
 476                 loopback_timer_start(dpcm);
 477         if (dpcm->period_update_pending) {
 478                 dpcm->period_update_pending = 0;
 479                 if (dpcm->cable->running & (1 << stream))
 480                         snd_pcm_period_elapsed(dpcm->substream);
 481         }
 482 }
 483
 484 static snd_pcm_uframes_t loopback_pointer(struct snd_pcm_substream *substream)
 485 {
 486         struct snd_pcm_runtime *runtime = substream->runtime;
 487         struct loopback_pcm *dpcm = runtime->private_data;
 488
 489         loopback_pos_update(dpcm->cable);
 490         return bytes_to_frames(runtime, dpcm->buf_pos);
 491 }
 492
 493 static struct snd_pcm_hardware loopback_pcm_hardware =
 494 {
 495         .info =         (SNDRV_PCM_INFO_INTERLEAVED | SNDRV_PCM_INFO_MMAP |
 496                          SNDRV_PCM_INFO_MMAP_VALID),
 497         .formats =      (SNDRV_PCM_FMTBIT_S16_LE | SNDRV_PCM_FMTBIT_S16_BE |
 498                          SNDRV_PCM_FMTBIT_S32_LE | SNDRV_PCM_FMTBIT_S32_BE |
 499                          SNDRV_PCM_FMTBIT_FLOAT_LE | SNDRV_PCM_FMTBIT_FLOAT_BE),
 500         .rates =        SNDRV_PCM_RATE_CONTINUOUS | SNDRV_PCM_RATE_8000_192000,
 501         .rate_min =             8000,
 502         .rate_max =             192000,
 503         .channels_min =         1,
 504         .channels_max =         32,
 505         .buffer_bytes_max =     2 * 1024 * 1024,
 506         .period_bytes_min =     64,
 507         .period_bytes_max =     2 * 1024 * 1024,
 508         .periods_min =          1,
 509         .periods_max =          1024,
 510         .fifo_size =            0,
 511 };
 512
 513 static void loopback_runtime_free(struct snd_pcm_runtime *runtime)
 514 {
 515         struct loopback_pcm *dpcm = runtime->private_data;
 516         kfree(dpcm);
 517 }
 518
 519 static int loopback_hw_params(struct snd_pcm_substream *substream,
 520                               struct snd_pcm_hw_params *params)
 521 {
 522         return snd_pcm_lib_malloc_pages(substream, params_buffer_bytes(params));
 523 }
 524
 525 static int loopback_hw_free(struct snd_pcm_substream *substream)
 526 {
 527         struct snd_pcm_runtime *runtime = substream->runtime;
 528         struct loopback_pcm *dpcm = runtime->private_data;
 529         struct loopback_cable *cable = dpcm->cable;
 530
 531         mutex_lock(&dpcm->loopback->cable_lock);
 532         cable->valid &= ~(1 << substream->stream);
 533         mutex_unlock(&dpcm->loopback->cable_lock);
 534         return snd_pcm_lib_free_pages(substream);
 535 }
 536
 537 static unsigned int get_cable_index(struct snd_pcm_substream *substream)
 538 {
 539         if (!substream->pcm->device)
 540                 return substream->stream;
 541         else
 542                 return !substream->stream;
 543 }
 544
 545 static int loopback_open(struct snd_pcm_substream *substream)
 546 {
 547         struct snd_pcm_runtime *runtime = substream->runtime;
 548         struct loopback *loopback = substream->private_data;
 549         struct loopback_pcm *dpcm;
 550         struct loopback_cable *cable;
 551         int err = 0;
 552         int dev = get_cable_index(substream);
 553
 554         mutex_lock(&loopback->cable_lock);
 555         dpcm = kzalloc(sizeof(*dpcm), GFP_KERNEL);
 556         if (!dpcm) {
 557                 err = -ENOMEM;
 558                 goto unlock;
 559         }
 560         dpcm->loopback = loopback;
 561         dpcm->substream = substream;
 562         setup_timer(&dpcm->timer, loopback_timer_function,
 563                     (unsigned long)dpcm);
 564
 565         cable = loopback->cables[substream->number][dev];
 566         if (!cable) {
 567                 cable = kzalloc(sizeof(*cable), GFP_KERNEL);
 568                 if (!cable) {
 569                         kfree(dpcm);
 570                         err = -ENOMEM;
 571                         goto unlock;
 572                 }
 573                 spin_lock_init(&cable->lock);
 574                 cable->hw = loopback_pcm_hardware;
 575                 loopback->cables[substream->number][dev] = cable;
 576         }
 577         dpcm->cable = cable;
 578         cable->streams[substream->stream] = dpcm;
 579
 580         snd_pcm_hw_constraint_integer(runtime, SNDRV_PCM_HW_PARAM_PERIODS);
 581
 582         runtime->private_data = dpcm;
 583         runtime->private_free = loopback_runtime_free;
 584         if (get_notify(dpcm) &&
 585             substream->stream == SNDRV_PCM_STREAM_PLAYBACK) {
 586                 runtime->hw = loopback_pcm_hardware;
 587         } else {
 588                 runtime->hw = cable->hw;
 589         }
 590  unlock:
 591         mutex_unlock(&loopback->cable_lock);
 592         return err;
 593 }
 594
 595 static int loopback_close(struct snd_pcm_substream *substream)
 596 {
 597         struct loopback *loopback = substream->private_data;
 598         struct loopback_pcm *dpcm = substream->runtime->private_data;
 599         struct loopback_cable *cable;
 600         int dev = get_cable_index(substream);
 601
 602         loopback_timer_stop(dpcm);
 603         mutex_lock(&loopback->cable_lock);
 604         cable = loopback->cables[substream->number][dev];
 605         if (cable->streams[!substream->stream]) {
 606                 /* other stream is still alive */
 607                 cable->streams[substream->stream] = NULL;
 608         } else {
 609                 /* free the cable */
 610                 loopback->cables[substream->number][dev] = NULL;
 611                 kfree(cable);
 612         }
 613         mutex_unlock(&loopback->cable_lock);
 614         return 0;
 615 }
 616
 617 static struct snd_pcm_ops loopback_playback_ops = {
 618         .open =         loopback_open,
 619         .close =        loopback_close,
 620         .ioctl =        snd_pcm_lib_ioctl,
 621         .hw_params =    loopback_hw_params,
 622         .hw_free =      loopback_hw_free,
 623         .prepare =      loopback_prepare,
 624         .trigger =      loopback_trigger,
 625         .pointer =      loopback_pointer,
 626 };
 627
 628 static struct snd_pcm_ops loopback_capture_ops = {
 629         .open =         loopback_open,
 630         .close =        loopback_close,
 631         .ioctl =        snd_pcm_lib_ioctl,
 632         .hw_params =    loopback_hw_params,
 633         .hw_free =      loopback_hw_free,
 634         .prepare =      loopback_prepare,
 635         .trigger =      loopback_trigger,
 636         .pointer =      loopback_pointer,
 637 };
 638
 639 static int __devinit loopback_pcm_new(struct loopback *loopback,
 640                                       int device, int substreams)
 641 {
 642         struct snd_pcm *pcm;
 643         int err;
 644
 645         err = snd_pcm_new(loopback->card, "Loopback PCM", device,
 646                           substreams, substreams, &pcm);
 647         if (err < 0)
 648                 return err;
 649         snd_pcm_set_ops(pcm, SNDRV_PCM_STREAM_PLAYBACK, &loopback_playback_ops);
 650         snd_pcm_set_ops(pcm, SNDRV_PCM_STREAM_CAPTURE, &loopback_capture_ops);
 651
 652         pcm->private_data = loopback;
 653         pcm->info_flags = 0;
 654         strcpy(pcm->name, "Loopback PCM");
 655
 656         loopback->pcm[device] = pcm;
 657
 658         snd_pcm_lib_preallocate_pages_for_all(pcm, SNDRV_DMA_TYPE_CONTINUOUS,
 659                         snd_dma_continuous_data(GFP_KERNEL),
 660                         0, 2 * 1024 * 1024);
 661         return 0;
 662 }
 663
 664 static int loopback_rate_shift_info(struct snd_kcontrol *kcontrol,
 665                                     struct snd_ctl_elem_info *uinfo)
 666 {
 667         uinfo->type = SNDRV_CTL_ELEM_TYPE_INTEGER;
 668         uinfo->count = 1;
 669         uinfo->value.integer.min = 80000;
 670         uinfo->value.integer.max = 120000;
 671         uinfo->value.integer.step = 1;
 672         return 0;
 673 }
 674
 675 static int loopback_rate_shift_get(struct snd_kcontrol *kcontrol,
 676                                    struct snd_ctl_elem_value *ucontrol)
 677 {
 678         struct loopback *loopback = snd_kcontrol_chip(kcontrol);
 679
 680         ucontrol->value.integer.value[0] =
 681                 loopback->setup[kcontrol->id.subdevice]
 682                                [kcontrol->id.device].rate_shift;
 683         return 0;
 684 }
 685
 686 static int loopback_rate_shift_put(struct snd_kcontrol *kcontrol,
 687                                    struct snd_ctl_elem_value *ucontrol)
 688 {
 689         struct loopback *loopback = snd_kcontrol_chip(kcontrol);
 690         unsigned int val;
 691         int change = 0;
 692
 693         val = ucontrol->value.integer.value[0];
 694         if (val < 80000)
 695                 val = 80000;
 696         if (val > 120000)
 697                 val = 120000;
 698         mutex_lock(&loopback->cable_lock);
 699         if (val != loopback->setup[kcontrol->id.subdevice]
 700                                   [kcontrol->id.device].rate_shift) {
 701                 loopback->setup[kcontrol->id.subdevice]
 702                                [kcontrol->id.device].rate_shift = val;
 703                 change = 1;
 704         }
 705         mutex_unlock(&loopback->cable_lock);
 706         return change;
 707 }
 708
 709 static int loopback_notify_get(struct snd_kcontrol *kcontrol,
 710                                struct snd_ctl_elem_value *ucontrol)
 711 {
 712         struct loopback *loopback = snd_kcontrol_chip(kcontrol);
 713
 714         ucontrol->value.integer.value[0] =
 715                 loopback->setup[kcontrol->id.subdevice]
 716                                [kcontrol->id.device].notify;
 717         return 0;
 718 }
 719
 720 static int loopback_notify_put(struct snd_kcontrol *kcontrol,
 721                                struct snd_ctl_elem_value *ucontrol)
 722 {
 723         struct loopback *loopback = snd_kcontrol_chip(kcontrol);
 724         unsigned int val;
 725         int change = 0;
 726
 727         val = ucontrol->value.integer.value[0] ? 1 : 0;
 728         if (val != loopback->setup[kcontrol->id.subdevice]
 729                                 [kcontrol->id.device].notify) {
 730                 loopback->setup[kcontrol->id.subdevice]
 731                         [kcontrol->id.device].notify = val;
 732                 change = 1;
 733         }
 734         return change;
 735 }
 736
 737 static int loopback_active_get(struct snd_kcontrol *kcontrol,
 738                                struct snd_ctl_elem_value *ucontrol)
 739 {
 740         struct loopback *loopback = snd_kcontrol_chip(kcontrol);
 741         struct loopback_cable *cable = loopback->cables
 742                         [kcontrol->id.subdevice][kcontrol->id.device ^ 1];
 743         unsigned int val = 0;
 744
 745         if (cable != NULL)
 746                 val = (cable->running & (1 << SNDRV_PCM_STREAM_PLAYBACK)) ?
 747                                                                         1 : 0;
 748         ucontrol->value.integer.value[0] = val;
 749         return 0;
 750 }
 751
 752 static int loopback_format_info(struct snd_kcontrol *kcontrol,
 753                                 struct snd_ctl_elem_info *uinfo)
 754 {
 755         uinfo->type = SNDRV_CTL_ELEM_TYPE_INTEGER;
 756         uinfo->count = 1;
 757         uinfo->value.integer.min = 0;
 758         uinfo->value.integer.max = SNDRV_PCM_FORMAT_LAST;
 759         uinfo->value.integer.step = 1;
 760         return 0;
 761 }
 762
 763 static int loopback_format_get(struct snd_kcontrol *kcontrol,
 764                                struct snd_ctl_elem_value *ucontrol)
 765 {
 766         struct loopback *loopback = snd_kcontrol_chip(kcontrol);
 767
 768         ucontrol->value.integer.value[0] =
 769                 loopback->setup[kcontrol->id.subdevice]
 770                                [kcontrol->id.device].format;
 771         return 0;
 772 }
 773
 774 static int loopback_rate_info(struct snd_kcontrol *kcontrol,
 775                               struct snd_ctl_elem_info *uinfo)
 776 {
 777         uinfo->type = SNDRV_CTL_ELEM_TYPE_INTEGER;
 778         uinfo->count = 1;
 779         uinfo->value.integer.min = 0;
 780         uinfo->value.integer.max = 192000;
 781         uinfo->value.integer.step = 1;
 782         return 0;
 783 }
 784
 785 static int loopback_rate_get(struct snd_kcontrol *kcontrol,
 786                              struct snd_ctl_elem_value *ucontrol)
 787 {
 788         struct loopback *loopback = snd_kcontrol_chip(kcontrol);
 789
 790         ucontrol->value.integer.value[0] =
 791                 loopback->setup[kcontrol->id.subdevice]
 792                                [kcontrol->id.device].rate;
 793         return 0;
 794 }
 795
 796 static int loopback_channels_info(struct snd_kcontrol *kcontrol,
 797                                   struct snd_ctl_elem_info *uinfo)
 798 {
 799         uinfo->type = SNDRV_CTL_ELEM_TYPE_INTEGER;
 800         uinfo->count = 1;
 801         uinfo->value.integer.min = 1;
 802         uinfo->value.integer.max = 1024;
 803         uinfo->value.integer.step = 1;
 804         return 0;
 805 }
 806
 807 static int loopback_channels_get(struct snd_kcontrol *kcontrol,
 808                                  struct snd_ctl_elem_value *ucontrol)
 809 {
 810         struct loopback *loopback = snd_kcontrol_chip(kcontrol);
 811
 812         ucontrol->value.integer.value[0] =
 813                 loopback->setup[kcontrol->id.subdevice]
 814                                [kcontrol->id.device].channels;
 815         return 0;
 816 }
 817
 818 static struct snd_kcontrol_new loopback_controls[]  __devinitdata = {
 819 {
 820         .iface =        SNDRV_CTL_ELEM_IFACE_PCM,
 821         .name =         "PCM Rate Shift 100000",
 822         .info =         loopback_rate_shift_info,
 823         .get =          loopback_rate_shift_get,
 824         .put =          loopback_rate_shift_put,
 825 },
 826 {
 827         .iface =        SNDRV_CTL_ELEM_IFACE_PCM,
 828         .name =         "PCM Notify",
 829         .info =         snd_ctl_boolean_mono_info,
 830         .get =          loopback_notify_get,
 831         .put =          loopback_notify_put,
 832 },
 833 #define ACTIVE_IDX 2
 834 {
 835         .access =       SNDRV_CTL_ELEM_ACCESS_READ,
 836         .iface =        SNDRV_CTL_ELEM_IFACE_PCM,
 837         .name =         "PCM Slave Active",
 838         .info =         snd_ctl_boolean_mono_info,
 839         .get =          loopback_active_get,
 840 },
 841 #define FORMAT_IDX 3
 842 {
 843         .access =       SNDRV_CTL_ELEM_ACCESS_READ,
 844         .iface =        SNDRV_CTL_ELEM_IFACE_PCM,
 845         .name =         "PCM Slave Format",
 846         .info =         loopback_format_info,
 847         .get =          loopback_format_get
 848 },
 849 #define RATE_IDX 4
 850 {
 851         .access =       SNDRV_CTL_ELEM_ACCESS_READ,
 852         .iface =        SNDRV_CTL_ELEM_IFACE_PCM,
 853         .name =         "PCM Slave Rate",
 854         .info =         loopback_rate_info,
 855         .get =          loopback_rate_get
 856 },
 857 #define CHANNELS_IDX 5
 858 {
 859         .access =       SNDRV_CTL_ELEM_ACCESS_READ,
 860         .iface =        SNDRV_CTL_ELEM_IFACE_PCM,
 861         .name =         "PCM Slave Channels",
 862         .info =         loopback_channels_info,
 863         .get =          loopback_channels_get
 864 }
 865 };
 866
 867 static int __devinit loopback_mixer_new(struct loopback *loopback, int notify)
 868 {
 869         struct snd_card *card = loopback->card;
 870         struct snd_pcm *pcm;
 871         struct snd_kcontrol *kctl;
 872         struct loopback_setup *setup;
 873         int err, dev, substr, substr_count, idx;
 874
 875         strcpy(card->mixername, "Loopback Mixer");
 876         for (dev = 0; dev < 2; dev++) {
 877                 pcm = loopback->pcm[dev];
 878                 substr_count =
 879                     pcm->streams[SNDRV_PCM_STREAM_CAPTURE].substream_count;
 880                 for (substr = 0; substr < substr_count; substr++) {
 881                         setup = &loopback->setup[substr][dev];
 882                         setup->notify = notify;
 883                         setup->rate_shift = NO_PITCH;
 884                         setup->format = SNDRV_PCM_FORMAT_S16_LE;
 885                         setup->rate = 48000;
 886                         setup->channels = 2;
 887                         for (idx = 0; idx < ARRAY_SIZE(loopback_controls);
 888                                                                         idx++) {
 889                                 kctl = snd_ctl_new1(&loopback_controls[idx],
 890                                                     loopback);
 891                                 if (!kctl)
 892                                         return -ENOMEM;
 893                                 kctl->id.device = dev;
 894                                 kctl->id.subdevice = substr;
 895                                 switch (idx) {
 896                                 case ACTIVE_IDX:
 897                                         setup->active_id = kctl->id;
 898                                         break;
 899                                 case FORMAT_IDX:
 900                                         setup->format_id = kctl->id;
 901                                         break;
 902                                 case RATE_IDX:
 903                                         setup->rate_id = kctl->id;
 904                                         break;
 905                                 case CHANNELS_IDX:
 906                                         setup->channels_id = kctl->id;
 907                                         break;
 908                                 default:
 909                                         break;
 910                                 }
 911                                 err = snd_ctl_add(card, kctl);
 912                                 if (err < 0)
 913                                         return err;
 914                         }
 915                 }
 916         }
 917         return 0;
 918 }
 919
 920 static int __devinit loopback_probe(struct platform_device *devptr)
 921 {
 922         struct snd_card *card;
 923         struct loopback *loopback;
 924         int dev = devptr->id;
 925         int err;
 926
 927         err = snd_card_create(index[dev], id[dev], THIS_MODULE,
 928                               sizeof(struct loopback), &card);
 929         if (err < 0)
 930                 return err;
 931         loopback = card->private_data;
 932
 933         if (pcm_substreams[dev] < 1)
 934                 pcm_substreams[dev] = 1;
 935         if (pcm_substreams[dev] > MAX_PCM_SUBSTREAMS)
 936                 pcm_substreams[dev] = MAX_PCM_SUBSTREAMS;
 937
 938         loopback->card = card;
 939         mutex_init(&loopback->cable_lock);
 940
 941         err = loopback_pcm_new(loopback, 0, pcm_substreams[dev]);
 942         if (err < 0)
 943                 goto __nodev;
 944         err = loopback_pcm_new(loopback, 1, pcm_substreams[dev]);
 945         if (err < 0)
 946                 goto __nodev;
 947         err = loopback_mixer_new(loopback, pcm_notify[dev] ? 1 : 0);
 948         if (err < 0)
 949                 goto __nodev;
 950         strcpy(card->driver, "Loopback");
 951         strcpy(card->shortname, "Loopback");
 952         sprintf(card->longname, "Loopback %i", dev + 1);
 953         err = snd_card_register(card);
 954         if (!err) {
 955                 platform_set_drvdata(devptr, card);
 956                 return 0;
 957         }
 958       __nodev:
 959         snd_card_free(card);
 960         return err;
 961 }
 962
 963 static int __devexit loopback_remove(struct platform_device *devptr)
 964 {
 965         snd_card_free(platform_get_drvdata(devptr));
 966         platform_set_drvdata(devptr, NULL);
 967         return 0;
 968 }
 969
 970 #ifdef CONFIG_PM
 971 static int loopback_suspend(struct platform_device *pdev,
 972                                 pm_message_t state)
 973 {
 974         struct snd_card *card = platform_get_drvdata(pdev);
 975         struct loopback *loopback = card->private_data;
 976
 977         snd_power_change_state(card, SNDRV_CTL_POWER_D3hot);
 978
 979         snd_pcm_suspend_all(loopback->pcm[0]);
 980         snd_pcm_suspend_all(loopback->pcm[1]);
 981         return 0;
 982 }
 983
 984 static int loopback_resume(struct platform_device *pdev)
 985 {
 986         struct snd_card *card = platform_get_drvdata(pdev);
 987
 988         snd_power_change_state(card, SNDRV_CTL_POWER_D0);
 989         return 0;
 990 }
 991 #endif
 992
 993 #define SND_LOOPBACK_DRIVER     "snd_aloop"
 994
 995 static struct platform_driver loopback_driver = {
 996         .probe          = loopback_probe,
 997         .remove         = __devexit_p(loopback_remove),
 998 #ifdef CONFIG_PM
 999         .suspend        = loopback_suspend,
1000         .resume         = loopback_resume,
1001 #endif
1002         .driver         = {
1003                 .name   = SND_LOOPBACK_DRIVER
1004         },
1005 };
1006
1007 static void loopback_unregister_all(void)
1008 {
1009         int i;
1010
1011         for (i = 0; i < ARRAY_SIZE(devices); ++i)
1012                 platform_device_unregister(devices[i]);
1013         platform_driver_unregister(&loopback_driver);
1014 }
1015
1016 static int __init alsa_card_loopback_init(void)
1017 {
1018         int i, err, cards;
1019
1020         err = platform_driver_register(&loopback_driver);
1021         if (err < 0)
1022                 return err;
1023
1024
1025         cards = 0;
1026         for (i = 0; i < SNDRV_CARDS; i++) {
1027                 struct platform_device *device;
1028                 if (!enable[i])
1029                         continue;
1030                 device = platform_device_register_simple(SND_LOOPBACK_DRIVER,
1031                                                          i, NULL, 0);
1032                 if (IS_ERR(device))
1033                         continue;
1034                 if (!platform_get_drvdata(device)) {
1035                         platform_device_unregister(device);
1036                         continue;
1037                 }
1038                 devices[i] = device;
1039                 cards++;
1040         }
1041         if (!cards) {
1042 #ifdef MODULE
1043                 printk(KERN_ERR "aloop: No loopback enabled\n");
1044 #endif
1045                 loopback_unregister_all();
1046                 return -ENODEV;
1047         }
1048         return 0;
1049 }
1050
1051 static void __exit alsa_card_loopback_exit(void)
1052 {
1053         loopback_unregister_all();
1054 }
1055
1056 module_init(alsa_card_loopback_init)
1057 module_exit(alsa_card_loopback_exit)