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