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, *cruntime;
 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         cruntime = cable->streams[SNDRV_PCM_STREAM_CAPTURE]->
 204                                                         substream->runtime;
 205         check = runtime->format != cruntime->format ||
 206                 runtime->rate != cruntime->rate ||
 207                 runtime->channels != cruntime->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 void params_change_substream(struct loopback_pcm *dpcm,
 278                                     struct snd_pcm_runtime *runtime)
 279 {
 280         struct snd_pcm_runtime *dst_runtime;
 281
 282         if (dpcm == NULL || dpcm->substream == NULL)
 283                 return;
 284         dst_runtime = dpcm->substream->runtime;
 285         if (dst_runtime == NULL)
 286                 return;
 287         dst_runtime->hw = dpcm->cable->hw;
 288 }
 289
 290 static void params_change(struct snd_pcm_substream *substream)
 291 {
 292         struct snd_pcm_runtime *runtime = substream->runtime;
 293         struct loopback_pcm *dpcm = runtime->private_data;
 294         struct loopback_cable *cable = dpcm->cable;
 295
 296         cable->hw.formats = (1ULL << runtime->format);
 297         cable->hw.rate_min = runtime->rate;
 298         cable->hw.rate_max = runtime->rate;
 299         cable->hw.channels_min = runtime->channels;
 300         cable->hw.channels_max = runtime->channels;
 301         params_change_substream(cable->streams[SNDRV_PCM_STREAM_PLAYBACK],
 302                                 runtime);
 303         params_change_substream(cable->streams[SNDRV_PCM_STREAM_CAPTURE],
 304                                 runtime);
 305 }
 306
 307 static int loopback_prepare(struct snd_pcm_substream *substream)
 308 {
 309         struct snd_pcm_runtime *runtime = substream->runtime;
 310         struct loopback_pcm *dpcm = runtime->private_data;
 311         struct loopback_cable *cable = dpcm->cable;
 312         int bps, salign;
 313
 314         salign = (snd_pcm_format_width(runtime->format) *
 315                                                 runtime->channels) / 8;
 316         bps = salign * runtime->rate;
 317         if (bps <= 0 || salign <= 0)
 318                 return -EINVAL;
 319
 320         dpcm->buf_pos = 0;
 321         dpcm->pcm_buffer_size = frames_to_bytes(runtime, runtime->buffer_size);
 322         if (substream->stream == SNDRV_PCM_STREAM_CAPTURE) {
 323                 /* clear capture buffer */
 324                 dpcm->silent_size = dpcm->pcm_buffer_size;
 325                 snd_pcm_format_set_silence(runtime->format, runtime->dma_area,
 326                                            runtime->buffer_size * runtime->channels);
 327         }
 328
 329         dpcm->irq_pos = 0;
 330         dpcm->period_update_pending = 0;
 331         dpcm->pcm_bps = bps;
 332         dpcm->pcm_salign = salign;
 333         dpcm->pcm_period_size = frames_to_bytes(runtime, runtime->period_size);
 334
 335         mutex_lock(&dpcm->loopback->cable_lock);
 336         if (!(cable->valid & ~(1 << substream->stream)) ||
 337             (get_setup(dpcm)->notify &&
 338              substream->stream == SNDRV_PCM_STREAM_PLAYBACK))
 339                 params_change(substream);
 340         cable->valid |= 1 << substream->stream;
 341         mutex_unlock(&dpcm->loopback->cable_lock);
 342
 343         return 0;
 344 }
 345
 346 static void clear_capture_buf(struct loopback_pcm *dpcm, unsigned int bytes)
 347 {
 348         struct snd_pcm_runtime *runtime = dpcm->substream->runtime;
 349         char *dst = runtime->dma_area;
 350         unsigned int dst_off = dpcm->buf_pos;
 351
 352         if (dpcm->silent_size >= dpcm->pcm_buffer_size)
 353                 return;
 354         if (dpcm->silent_size + bytes > dpcm->pcm_buffer_size)
 355                 bytes = dpcm->pcm_buffer_size - dpcm->silent_size;
 356
 357         for (;;) {
 358                 unsigned int size = bytes;
 359                 if (dst_off + size > dpcm->pcm_buffer_size)
 360                         size = dpcm->pcm_buffer_size - dst_off;
 361                 snd_pcm_format_set_silence(runtime->format, dst + dst_off,
 362                                            bytes_to_frames(runtime, size) *
 363                                                 runtime->channels);
 364                 dpcm->silent_size += size;
 365                 bytes -= size;
 366                 if (!bytes)
 367                         break;
 368                 dst_off = 0;
 369         }
 370 }
 371
 372 static void copy_play_buf(struct loopback_pcm *play,
 373                           struct loopback_pcm *capt,
 374                           unsigned int bytes)
 375 {
 376         struct snd_pcm_runtime *runtime = play->substream->runtime;
 377         char *src = runtime->dma_area;
 378         char *dst = capt->substream->runtime->dma_area;
 379         unsigned int src_off = play->buf_pos;
 380         unsigned int dst_off = capt->buf_pos;
 381         unsigned int clear_bytes = 0;
 382
 383         /* check if playback is draining, trim the capture copy size
 384          * when our pointer is at the end of playback ring buffer */
 385         if (runtime->status->state == SNDRV_PCM_STATE_DRAINING &&
 386             snd_pcm_playback_hw_avail(runtime) < runtime->buffer_size) {
 387                 snd_pcm_uframes_t appl_ptr, appl_ptr1, diff;
 388                 appl_ptr = appl_ptr1 = runtime->control->appl_ptr;
 389                 appl_ptr1 -= appl_ptr1 % runtime->buffer_size;
 390                 appl_ptr1 += play->buf_pos / play->pcm_salign;
 391                 if (appl_ptr < appl_ptr1)
 392                         appl_ptr1 -= runtime->buffer_size;
 393                 diff = (appl_ptr - appl_ptr1) * play->pcm_salign;
 394                 if (diff < bytes) {
 395                         clear_bytes = bytes - diff;
 396                         bytes = diff;
 397                 }
 398         }
 399
 400         for (;;) {
 401                 unsigned int size = bytes;
 402                 if (src_off + size > play->pcm_buffer_size)
 403                         size = play->pcm_buffer_size - src_off;
 404                 if (dst_off + size > capt->pcm_buffer_size)
 405                         size = capt->pcm_buffer_size - dst_off;
 406                 memcpy(dst + dst_off, src + src_off, size);
 407                 capt->silent_size = 0;
 408                 bytes -= size;
 409                 if (!bytes)
 410                         break;
 411                 src_off = (src_off + size) % play->pcm_buffer_size;
 412                 dst_off = (dst_off + size) % capt->pcm_buffer_size;
 413         }
 414
 415         if (clear_bytes > 0) {
 416                 clear_capture_buf(capt, clear_bytes);
 417                 capt->silent_size = 0;
 418         }
 419 }
 420
 421 #define BYTEPOS_UPDATE_POSONLY  0
 422 #define BYTEPOS_UPDATE_CLEAR    1
 423 #define BYTEPOS_UPDATE_COPY     2
 424
 425 static void loopback_bytepos_update(struct loopback_pcm *dpcm,
 426                                     unsigned int delta,
 427                                     unsigned int cmd)
 428 {
 429         unsigned int count;
 430         unsigned long last_pos;
 431
 432         last_pos = byte_pos(dpcm, dpcm->irq_pos);
 433         dpcm->irq_pos += delta * dpcm->pcm_bps;
 434         count = byte_pos(dpcm, dpcm->irq_pos) - last_pos;
 435         if (!count)
 436                 return;
 437         if (cmd == BYTEPOS_UPDATE_CLEAR)
 438                 clear_capture_buf(dpcm, count);
 439         else if (cmd == BYTEPOS_UPDATE_COPY)
 440                 copy_play_buf(dpcm->cable->streams[SNDRV_PCM_STREAM_PLAYBACK],
 441                               dpcm->cable->streams[SNDRV_PCM_STREAM_CAPTURE],
 442                               count);
 443         dpcm->buf_pos += count;
 444         dpcm->buf_pos %= dpcm->pcm_buffer_size;
 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 }
 450
 451 static void loopback_pos_update(struct loopback_cable *cable)
 452 {
 453         struct loopback_pcm *dpcm_play =
 454                         cable->streams[SNDRV_PCM_STREAM_PLAYBACK];
 455         struct loopback_pcm *dpcm_capt =
 456                         cable->streams[SNDRV_PCM_STREAM_CAPTURE];
 457         unsigned long delta_play = 0, delta_capt = 0;
 458
 459         spin_lock(&cable->lock);
 460         if (cable->running & (1 << SNDRV_PCM_STREAM_PLAYBACK)) {
 461                 delta_play = jiffies - dpcm_play->last_jiffies;
 462                 dpcm_play->last_jiffies += delta_play;
 463         }
 464
 465         if (cable->running & (1 << SNDRV_PCM_STREAM_CAPTURE)) {
 466                 delta_capt = jiffies - dpcm_capt->last_jiffies;
 467                 dpcm_capt->last_jiffies += delta_capt;
 468         }
 469
 470         if (delta_play == 0 && delta_capt == 0) {
 471                 spin_unlock(&cable->lock);
 472                 return;
 473         }
 474
 475         if (delta_play > delta_capt) {
 476                 loopback_bytepos_update(dpcm_play, delta_play - delta_capt,
 477                                         BYTEPOS_UPDATE_POSONLY);
 478                 delta_play = delta_capt;
 479         } else if (delta_play < delta_capt) {
 480                 loopback_bytepos_update(dpcm_capt, delta_capt - delta_play,
 481                                         BYTEPOS_UPDATE_CLEAR);
 482                 delta_capt = delta_play;
 483         }
 484
 485         if (delta_play == 0 && delta_capt == 0) {
 486                 spin_unlock(&cable->lock);
 487                 return;
 488         }
 489         /* note delta_capt == delta_play at this moment */
 490         loopback_bytepos_update(dpcm_capt, delta_capt, BYTEPOS_UPDATE_COPY);
 491         loopback_bytepos_update(dpcm_play, delta_play, BYTEPOS_UPDATE_POSONLY);
 492         spin_unlock(&cable->lock);
 493 }
 494
 495 static void loopback_timer_function(unsigned long data)
 496 {
 497         struct loopback_pcm *dpcm = (struct loopback_pcm *)data;
 498         int stream;
 499
 500         loopback_pos_update(dpcm->cable);
 501         stream = dpcm->substream->stream;
 502         if (dpcm->cable->running & (1 << stream))
 503                 loopback_timer_start(dpcm);
 504         if (dpcm->period_update_pending) {
 505                 dpcm->period_update_pending = 0;
 506                 if (dpcm->cable->running & (1 << stream))
 507                         snd_pcm_period_elapsed(dpcm->substream);
 508         }
 509 }
 510
 511 static snd_pcm_uframes_t loopback_pointer(struct snd_pcm_substream *substream)
 512 {
 513         struct snd_pcm_runtime *runtime = substream->runtime;
 514         struct loopback_pcm *dpcm = runtime->private_data;
 515
 516         loopback_pos_update(dpcm->cable);
 517         return bytes_to_frames(runtime, dpcm->buf_pos);
 518 }
 519
 520 static struct snd_pcm_hardware loopback_pcm_hardware =
 521 {
 522         .info =         (SNDRV_PCM_INFO_INTERLEAVED | SNDRV_PCM_INFO_MMAP |
 523                          SNDRV_PCM_INFO_MMAP_VALID),
 524         .formats =      (SNDRV_PCM_FMTBIT_S16_LE | SNDRV_PCM_FMTBIT_S16_BE |
 525                          SNDRV_PCM_FMTBIT_S32_LE | SNDRV_PCM_FMTBIT_S32_BE |
 526                          SNDRV_PCM_FMTBIT_FLOAT_LE | SNDRV_PCM_FMTBIT_FLOAT_BE),
 527         .rates =        SNDRV_PCM_RATE_CONTINUOUS | SNDRV_PCM_RATE_8000_192000,
 528         .rate_min =             8000,
 529         .rate_max =             192000,
 530         .channels_min =         1,
 531         .channels_max =         32,
 532         .buffer_bytes_max =     2 * 1024 * 1024,
 533         .period_bytes_min =     64,
 534         .period_bytes_max =     2 * 1024 * 1024,
 535         .periods_min =          1,
 536         .periods_max =          1024,
 537         .fifo_size =            0,
 538 };
 539
 540 static void loopback_runtime_free(struct snd_pcm_runtime *runtime)
 541 {
 542         struct loopback_pcm *dpcm = runtime->private_data;
 543         kfree(dpcm);
 544 }
 545
 546 static int loopback_hw_params(struct snd_pcm_substream *substream,
 547                               struct snd_pcm_hw_params *params)
 548 {
 549         return snd_pcm_lib_malloc_pages(substream, params_buffer_bytes(params));
 550 }
 551
 552 static int loopback_hw_free(struct snd_pcm_substream *substream)
 553 {
 554         struct snd_pcm_runtime *runtime = substream->runtime;
 555         struct loopback_pcm *dpcm = runtime->private_data;
 556         struct loopback_cable *cable = dpcm->cable;
 557
 558         mutex_lock(&dpcm->loopback->cable_lock);
 559         cable->valid &= ~(1 << substream->stream);
 560         mutex_unlock(&dpcm->loopback->cable_lock);
 561         return snd_pcm_lib_free_pages(substream);
 562 }
 563
 564 static unsigned int get_cable_index(struct snd_pcm_substream *substream)
 565 {
 566         if (!substream->pcm->device)
 567                 return substream->stream;
 568         else
 569                 return !substream->stream;
 570 }
 571
 572 static int rule_format(struct snd_pcm_hw_params *params,
 573                        struct snd_pcm_hw_rule *rule)
 574 {
 575
 576         struct snd_pcm_hardware *hw = rule->private;
 577         struct snd_mask *maskp = hw_param_mask(params, rule->var);
 578
 579         maskp->bits[0] &= (u_int32_t)hw->formats;
 580         maskp->bits[1] &= (u_int32_t)(hw->formats >> 32);
 581         memset(maskp->bits + 2, 0, (SNDRV_MASK_MAX-64) / 8); /* clear rest */
 582         if (! maskp->bits[0] && ! maskp->bits[1])
 583                 return -EINVAL;
 584         return 0;
 585 }
 586
 587 static int rule_rate(struct snd_pcm_hw_params *params,
 588                      struct snd_pcm_hw_rule *rule)
 589 {
 590         struct snd_pcm_hardware *hw = rule->private;
 591         struct snd_interval t;
 592
 593         t.min = hw->rate_min;
 594         t.max = hw->rate_max;
 595         t.openmin = t.openmax = 0;
 596         t.integer = 0;
 597         return snd_interval_refine(hw_param_interval(params, rule->var), &t);
 598 }
 599
 600 static int rule_channels(struct snd_pcm_hw_params *params,
 601                          struct snd_pcm_hw_rule *rule)
 602 {
 603         struct snd_pcm_hardware *hw = rule->private;
 604         struct snd_interval t;
 605
 606         t.min = hw->channels_min;
 607         t.max = hw->channels_max;
 608         t.openmin = t.openmax = 0;
 609         t.integer = 0;
 610         return snd_interval_refine(hw_param_interval(params, rule->var), &t);
 611 }
 612
 613 static int loopback_open(struct snd_pcm_substream *substream)
 614 {
 615         struct snd_pcm_runtime *runtime = substream->runtime;
 616         struct loopback *loopback = substream->private_data;
 617         struct loopback_pcm *dpcm;
 618         struct loopback_cable *cable;
 619         int err = 0;
 620         int dev = get_cable_index(substream);
 621
 622         mutex_lock(&loopback->cable_lock);
 623         dpcm = kzalloc(sizeof(*dpcm), GFP_KERNEL);
 624         if (!dpcm) {
 625                 err = -ENOMEM;
 626                 goto unlock;
 627         }
 628         dpcm->loopback = loopback;
 629         dpcm->substream = substream;
 630         setup_timer(&dpcm->timer, loopback_timer_function,
 631                     (unsigned long)dpcm);
 632
 633         cable = loopback->cables[substream->number][dev];
 634         if (!cable) {
 635                 cable = kzalloc(sizeof(*cable), GFP_KERNEL);
 636                 if (!cable) {
 637                         kfree(dpcm);
 638                         err = -ENOMEM;
 639                         goto unlock;
 640                 }
 641                 spin_lock_init(&cable->lock);
 642                 cable->hw = loopback_pcm_hardware;
 643                 loopback->cables[substream->number][dev] = cable;
 644         }
 645         dpcm->cable = cable;
 646         cable->streams[substream->stream] = dpcm;
 647
 648         snd_pcm_hw_constraint_integer(runtime, SNDRV_PCM_HW_PARAM_PERIODS);
 649
 650         /* use dynamic rules based on actual runtime->hw values */
 651         /* note that the default rules created in the PCM midlevel code */
 652         /* are cached -> they do not reflect the actual state */
 653         err = snd_pcm_hw_rule_add(runtime, 0,
 654                                   SNDRV_PCM_HW_PARAM_FORMAT,
 655                                   rule_format, &runtime->hw,
 656                                   SNDRV_PCM_HW_PARAM_FORMAT, -1);
 657         if (err < 0)
 658                 goto unlock;
 659         err = snd_pcm_hw_rule_add(runtime, 0,
 660                                   SNDRV_PCM_HW_PARAM_RATE,
 661                                   rule_rate, &runtime->hw,
 662                                   SNDRV_PCM_HW_PARAM_RATE, -1);
 663         if (err < 0)
 664                 goto unlock;
 665         err = snd_pcm_hw_rule_add(runtime, 0,
 666                                   SNDRV_PCM_HW_PARAM_CHANNELS,
 667                                   rule_channels, &runtime->hw,
 668                                   SNDRV_PCM_HW_PARAM_CHANNELS, -1);
 669         if (err < 0)
 670                 goto unlock;
 671
 672         runtime->private_data = dpcm;
 673         runtime->private_free = loopback_runtime_free;
 674         if (get_notify(dpcm))
 675                 runtime->hw = loopback_pcm_hardware;
 676         else
 677                 runtime->hw = cable->hw;
 678  unlock:
 679         mutex_unlock(&loopback->cable_lock);
 680         return err;
 681 }
 682
 683 static int loopback_close(struct snd_pcm_substream *substream)
 684 {
 685         struct loopback *loopback = substream->private_data;
 686         struct loopback_pcm *dpcm = substream->runtime->private_data;
 687         struct loopback_cable *cable;
 688         int dev = get_cable_index(substream);
 689
 690         loopback_timer_stop(dpcm);
 691         mutex_lock(&loopback->cable_lock);
 692         cable = loopback->cables[substream->number][dev];
 693         if (cable->streams[!substream->stream]) {
 694                 /* other stream is still alive */
 695                 cable->streams[substream->stream] = NULL;
 696         } else {
 697                 /* free the cable */
 698                 loopback->cables[substream->number][dev] = NULL;
 699                 kfree(cable);
 700         }
 701         mutex_unlock(&loopback->cable_lock);
 702         return 0;
 703 }
 704
 705 static struct snd_pcm_ops loopback_playback_ops = {
 706         .open =         loopback_open,
 707         .close =        loopback_close,
 708         .ioctl =        snd_pcm_lib_ioctl,
 709         .hw_params =    loopback_hw_params,
 710         .hw_free =      loopback_hw_free,
 711         .prepare =      loopback_prepare,
 712         .trigger =      loopback_trigger,
 713         .pointer =      loopback_pointer,
 714 };
 715
 716 static struct snd_pcm_ops loopback_capture_ops = {
 717         .open =         loopback_open,
 718         .close =        loopback_close,
 719         .ioctl =        snd_pcm_lib_ioctl,
 720         .hw_params =    loopback_hw_params,
 721         .hw_free =      loopback_hw_free,
 722         .prepare =      loopback_prepare,
 723         .trigger =      loopback_trigger,
 724         .pointer =      loopback_pointer,
 725 };
 726
 727 static int __devinit loopback_pcm_new(struct loopback *loopback,
 728                                       int device, int substreams)
 729 {
 730         struct snd_pcm *pcm;
 731         int err;
 732
 733         err = snd_pcm_new(loopback->card, "Loopback PCM", device,
 734                           substreams, substreams, &pcm);
 735         if (err < 0)
 736                 return err;
 737         snd_pcm_set_ops(pcm, SNDRV_PCM_STREAM_PLAYBACK, &loopback_playback_ops);
 738         snd_pcm_set_ops(pcm, SNDRV_PCM_STREAM_CAPTURE, &loopback_capture_ops);
 739
 740         pcm->private_data = loopback;
 741         pcm->info_flags = 0;
 742         strcpy(pcm->name, "Loopback PCM");
 743
 744         loopback->pcm[device] = pcm;
 745
 746         snd_pcm_lib_preallocate_pages_for_all(pcm, SNDRV_DMA_TYPE_CONTINUOUS,
 747                         snd_dma_continuous_data(GFP_KERNEL),
 748                         0, 2 * 1024 * 1024);
 749         return 0;
 750 }
 751
 752 static int loopback_rate_shift_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 = 80000;
 758         uinfo->value.integer.max = 120000;
 759         uinfo->value.integer.step = 1;
 760         return 0;
 761 }
 762
 763 static int loopback_rate_shift_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].rate_shift;
 771         return 0;
 772 }
 773
 774 static int loopback_rate_shift_put(struct snd_kcontrol *kcontrol,
 775                                    struct snd_ctl_elem_value *ucontrol)
 776 {
 777         struct loopback *loopback = snd_kcontrol_chip(kcontrol);
 778         unsigned int val;
 779         int change = 0;
 780
 781         val = ucontrol->value.integer.value[0];
 782         if (val < 80000)
 783                 val = 80000;
 784         if (val > 120000)
 785                 val = 120000;
 786         mutex_lock(&loopback->cable_lock);
 787         if (val != loopback->setup[kcontrol->id.subdevice]
 788                                   [kcontrol->id.device].rate_shift) {
 789                 loopback->setup[kcontrol->id.subdevice]
 790                                [kcontrol->id.device].rate_shift = val;
 791                 change = 1;
 792         }
 793         mutex_unlock(&loopback->cable_lock);
 794         return change;
 795 }
 796
 797 static int loopback_notify_get(struct snd_kcontrol *kcontrol,
 798                                struct snd_ctl_elem_value *ucontrol)
 799 {
 800         struct loopback *loopback = snd_kcontrol_chip(kcontrol);
 801
 802         ucontrol->value.integer.value[0] =
 803                 loopback->setup[kcontrol->id.subdevice]
 804                                [kcontrol->id.device].notify;
 805         return 0;
 806 }
 807
 808 static int loopback_notify_put(struct snd_kcontrol *kcontrol,
 809                                struct snd_ctl_elem_value *ucontrol)
 810 {
 811         struct loopback *loopback = snd_kcontrol_chip(kcontrol);
 812         unsigned int val;
 813         int change = 0;
 814
 815         val = ucontrol->value.integer.value[0] ? 1 : 0;
 816         if (val != loopback->setup[kcontrol->id.subdevice]
 817                                 [kcontrol->id.device].notify) {
 818                 loopback->setup[kcontrol->id.subdevice]
 819                         [kcontrol->id.device].notify = val;
 820                 change = 1;
 821         }
 822         return change;
 823 }
 824
 825 static int loopback_active_get(struct snd_kcontrol *kcontrol,
 826                                struct snd_ctl_elem_value *ucontrol)
 827 {
 828         struct loopback *loopback = snd_kcontrol_chip(kcontrol);
 829         struct loopback_cable *cable = loopback->cables
 830                         [kcontrol->id.subdevice][kcontrol->id.device ^ 1];
 831         unsigned int val = 0;
 832
 833         if (cable != NULL)
 834                 val = (cable->running & (1 << SNDRV_PCM_STREAM_PLAYBACK)) ?
 835                                                                         1 : 0;
 836         ucontrol->value.integer.value[0] = val;
 837         return 0;
 838 }
 839
 840 static int loopback_format_info(struct snd_kcontrol *kcontrol,
 841                                 struct snd_ctl_elem_info *uinfo)
 842 {
 843         uinfo->type = SNDRV_CTL_ELEM_TYPE_INTEGER;
 844         uinfo->count = 1;
 845         uinfo->value.integer.min = 0;
 846         uinfo->value.integer.max = SNDRV_PCM_FORMAT_LAST;
 847         uinfo->value.integer.step = 1;
 848         return 0;
 849 }
 850
 851 static int loopback_format_get(struct snd_kcontrol *kcontrol,
 852                                struct snd_ctl_elem_value *ucontrol)
 853 {
 854         struct loopback *loopback = snd_kcontrol_chip(kcontrol);
 855
 856         ucontrol->value.integer.value[0] =
 857                 loopback->setup[kcontrol->id.subdevice]
 858                                [kcontrol->id.device].format;
 859         return 0;
 860 }
 861
 862 static int loopback_rate_info(struct snd_kcontrol *kcontrol,
 863                               struct snd_ctl_elem_info *uinfo)
 864 {
 865         uinfo->type = SNDRV_CTL_ELEM_TYPE_INTEGER;
 866         uinfo->count = 1;
 867         uinfo->value.integer.min = 0;
 868         uinfo->value.integer.max = 192000;
 869         uinfo->value.integer.step = 1;
 870         return 0;
 871 }
 872
 873 static int loopback_rate_get(struct snd_kcontrol *kcontrol,
 874                              struct snd_ctl_elem_value *ucontrol)
 875 {
 876         struct loopback *loopback = snd_kcontrol_chip(kcontrol);
 877
 878         ucontrol->value.integer.value[0] =
 879                 loopback->setup[kcontrol->id.subdevice]
 880                                [kcontrol->id.device].rate;
 881         return 0;
 882 }
 883
 884 static int loopback_channels_info(struct snd_kcontrol *kcontrol,
 885                                   struct snd_ctl_elem_info *uinfo)
 886 {
 887         uinfo->type = SNDRV_CTL_ELEM_TYPE_INTEGER;
 888         uinfo->count = 1;
 889         uinfo->value.integer.min = 1;
 890         uinfo->value.integer.max = 1024;
 891         uinfo->value.integer.step = 1;
 892         return 0;
 893 }
 894
 895 static int loopback_channels_get(struct snd_kcontrol *kcontrol,
 896                                  struct snd_ctl_elem_value *ucontrol)
 897 {
 898         struct loopback *loopback = snd_kcontrol_chip(kcontrol);
 899
 900         ucontrol->value.integer.value[0] =
 901                 loopback->setup[kcontrol->id.subdevice]
 902                                [kcontrol->id.device].channels;
 903         return 0;
 904 }
 905
 906 static struct snd_kcontrol_new loopback_controls[]  __devinitdata = {
 907 {
 908         .iface =        SNDRV_CTL_ELEM_IFACE_PCM,
 909         .name =         "PCM Rate Shift 100000",
 910         .info =         loopback_rate_shift_info,
 911         .get =          loopback_rate_shift_get,
 912         .put =          loopback_rate_shift_put,
 913 },
 914 {
 915         .iface =        SNDRV_CTL_ELEM_IFACE_PCM,
 916         .name =         "PCM Notify",
 917         .info =         snd_ctl_boolean_mono_info,
 918         .get =          loopback_notify_get,
 919         .put =          loopback_notify_put,
 920 },
 921 #define ACTIVE_IDX 2
 922 {
 923         .access =       SNDRV_CTL_ELEM_ACCESS_READ,
 924         .iface =        SNDRV_CTL_ELEM_IFACE_PCM,
 925         .name =         "PCM Slave Active",
 926         .info =         snd_ctl_boolean_mono_info,
 927         .get =          loopback_active_get,
 928 },
 929 #define FORMAT_IDX 3
 930 {
 931         .access =       SNDRV_CTL_ELEM_ACCESS_READ,
 932         .iface =        SNDRV_CTL_ELEM_IFACE_PCM,
 933         .name =         "PCM Slave Format",
 934         .info =         loopback_format_info,
 935         .get =          loopback_format_get
 936 },
 937 #define RATE_IDX 4
 938 {
 939         .access =       SNDRV_CTL_ELEM_ACCESS_READ,
 940         .iface =        SNDRV_CTL_ELEM_IFACE_PCM,
 941         .name =         "PCM Slave Rate",
 942         .info =         loopback_rate_info,
 943         .get =          loopback_rate_get
 944 },
 945 #define CHANNELS_IDX 5
 946 {
 947         .access =       SNDRV_CTL_ELEM_ACCESS_READ,
 948         .iface =        SNDRV_CTL_ELEM_IFACE_PCM,
 949         .name =         "PCM Slave Channels",
 950         .info =         loopback_channels_info,
 951         .get =          loopback_channels_get
 952 }
 953 };
 954
 955 static int __devinit loopback_mixer_new(struct loopback *loopback, int notify)
 956 {
 957         struct snd_card *card = loopback->card;
 958         struct snd_pcm *pcm;
 959         struct snd_kcontrol *kctl;
 960         struct loopback_setup *setup;
 961         int err, dev, substr, substr_count, idx;
 962
 963         strcpy(card->mixername, "Loopback Mixer");
 964         for (dev = 0; dev < 2; dev++) {
 965                 pcm = loopback->pcm[dev];
 966                 substr_count =
 967                     pcm->streams[SNDRV_PCM_STREAM_CAPTURE].substream_count;
 968                 for (substr = 0; substr < substr_count; substr++) {
 969                         setup = &loopback->setup[substr][dev];
 970                         setup->notify = notify;
 971                         setup->rate_shift = NO_PITCH;
 972                         setup->format = SNDRV_PCM_FORMAT_S16_LE;
 973                         setup->rate = 48000;
 974                         setup->channels = 2;
 975                         for (idx = 0; idx < ARRAY_SIZE(loopback_controls);
 976                                                                         idx++) {
 977                                 kctl = snd_ctl_new1(&loopback_controls[idx],
 978                                                     loopback);
 979                                 if (!kctl)
 980                                         return -ENOMEM;
 981                                 kctl->id.device = dev;
 982                                 kctl->id.subdevice = substr;
 983                                 switch (idx) {
 984                                 case ACTIVE_IDX:
 985                                         setup->active_id = kctl->id;
 986                                         break;
 987                                 case FORMAT_IDX:
 988                                         setup->format_id = kctl->id;
 989                                         break;
 990                                 case RATE_IDX:
 991                                         setup->rate_id = kctl->id;
 992                                         break;
 993                                 case CHANNELS_IDX:
 994                                         setup->channels_id = kctl->id;
 995                                         break;
 996                                 default:
 997                                         break;
 998                                 }
 999                                 err = snd_ctl_add(card, kctl);
1000                                 if (err < 0)
1001                                         return err;
1002                         }
1003                 }
1004         }
1005         return 0;
1006 }
1007
1008 static int __devinit loopback_probe(struct platform_device *devptr)
1009 {
1010         struct snd_card *card;
1011         struct loopback *loopback;
1012         int dev = devptr->id;
1013         int err;
1014
1015         err = snd_card_create(index[dev], id[dev], THIS_MODULE,
1016                               sizeof(struct loopback), &card);
1017         if (err < 0)
1018                 return err;
1019         loopback = card->private_data;
1020
1021         if (pcm_substreams[dev] < 1)
1022                 pcm_substreams[dev] = 1;
1023         if (pcm_substreams[dev] > MAX_PCM_SUBSTREAMS)
1024                 pcm_substreams[dev] = MAX_PCM_SUBSTREAMS;
1025
1026         loopback->card = card;
1027         mutex_init(&loopback->cable_lock);
1028
1029         err = loopback_pcm_new(loopback, 0, pcm_substreams[dev]);
1030         if (err < 0)
1031                 goto __nodev;
1032         err = loopback_pcm_new(loopback, 1, pcm_substreams[dev]);
1033         if (err < 0)
1034                 goto __nodev;
1035         err = loopback_mixer_new(loopback, pcm_notify[dev] ? 1 : 0);
1036         if (err < 0)
1037                 goto __nodev;
1038         strcpy(card->driver, "Loopback");
1039         strcpy(card->shortname, "Loopback");
1040         sprintf(card->longname, "Loopback %i", dev + 1);
1041         err = snd_card_register(card);
1042         if (!err) {
1043                 platform_set_drvdata(devptr, card);
1044                 return 0;
1045         }
1046       __nodev:
1047         snd_card_free(card);
1048         return err;
1049 }
1050
1051 static int __devexit loopback_remove(struct platform_device *devptr)
1052 {
1053         snd_card_free(platform_get_drvdata(devptr));
1054         platform_set_drvdata(devptr, NULL);
1055         return 0;
1056 }
1057
1058 #ifdef CONFIG_PM
1059 static int loopback_suspend(struct platform_device *pdev,
1060                                 pm_message_t state)
1061 {
1062         struct snd_card *card = platform_get_drvdata(pdev);
1063         struct loopback *loopback = card->private_data;
1064
1065         snd_power_change_state(card, SNDRV_CTL_POWER_D3hot);
1066
1067         snd_pcm_suspend_all(loopback->pcm[0]);
1068         snd_pcm_suspend_all(loopback->pcm[1]);
1069         return 0;
1070 }
1071
1072 static int loopback_resume(struct platform_device *pdev)
1073 {
1074         struct snd_card *card = platform_get_drvdata(pdev);
1075
1076         snd_power_change_state(card, SNDRV_CTL_POWER_D0);
1077         return 0;
1078 }
1079 #endif
1080
1081 #define SND_LOOPBACK_DRIVER     "snd_aloop"
1082
1083 static struct platform_driver loopback_driver = {
1084         .probe          = loopback_probe,
1085         .remove         = __devexit_p(loopback_remove),
1086 #ifdef CONFIG_PM
1087         .suspend        = loopback_suspend,
1088         .resume         = loopback_resume,
1089 #endif
1090         .driver         = {
1091                 .name   = SND_LOOPBACK_DRIVER
1092         },
1093 };
1094
1095 static void loopback_unregister_all(void)
1096 {
1097         int i;
1098
1099         for (i = 0; i < ARRAY_SIZE(devices); ++i)
1100                 platform_device_unregister(devices[i]);
1101         platform_driver_unregister(&loopback_driver);
1102 }
1103
1104 static int __init alsa_card_loopback_init(void)
1105 {
1106         int i, err, cards;
1107
1108         err = platform_driver_register(&loopback_driver);
1109         if (err < 0)
1110                 return err;
1111
1112
1113         cards = 0;
1114         for (i = 0; i < SNDRV_CARDS; i++) {
1115                 struct platform_device *device;
1116                 if (!enable[i])
1117                         continue;
1118                 device = platform_device_register_simple(SND_LOOPBACK_DRIVER,
1119                                                          i, NULL, 0);
1120                 if (IS_ERR(device))
1121                         continue;
1122                 if (!platform_get_drvdata(device)) {
1123                         platform_device_unregister(device);
1124                         continue;
1125                 }
1126                 devices[i] = device;
1127                 cards++;
1128         }
1129         if (!cards) {
1130 #ifdef MODULE
1131                 printk(KERN_ERR "aloop: No loopback enabled\n");
1132 #endif
1133                 loopback_unregister_all();
1134                 return -ENODEV;
1135         }
1136         return 0;
1137 }
1138
1139 static void __exit alsa_card_loopback_exit(void)
1140 {
1141         loopback_unregister_all();
1142 }
1143
1144 module_init(alsa_card_loopback_init)
1145 module_exit(alsa_card_loopback_exit)