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