sound/drivers/aloop.c

   1 // SPDX-License-Identifier: GPL-2.0-or-later
   2 /*
   3  *  Loopback soundcard
   4  *
   5  *  Original code:
   6  *  Copyright (c) by Jaroslav Kysela <perex@perex.cz>
   7  *
   8  *  More accurate positioning and full-duplex support:
   9  *  Copyright (c) Ahmet İnan <ainan at mathematik.uni-freiburg.de>
  10  *
  11  *  Major (almost complete) rewrite:
  12  *  Copyright (c) by Takashi Iwai <tiwai@suse.de>
  13  *
  14  *  A next major update in 2010 (separate timers for playback and capture):
  15  *  Copyright (c) Jaroslav Kysela <perex@perex.cz>
  16  */
  17
  18 #include <linux/init.h>
  19 #include <linux/jiffies.h>
  20 #include <linux/slab.h>
  21 #include <linux/time.h>
  22 #include <linux/wait.h>
  23 #include <linux/module.h>
  24 #include <linux/platform_device.h>
  25 #include <sound/core.h>
  26 #include <sound/control.h>
  27 #include <sound/pcm.h>
  28 #include <sound/pcm_params.h>
  29 #include <sound/info.h>
  30 #include <sound/initval.h>
  31 #include <sound/timer.h>
  32
  33 MODULE_AUTHOR("Jaroslav Kysela <perex@perex.cz>");
  34 MODULE_DESCRIPTION("A loopback soundcard");
  35 MODULE_LICENSE("GPL");
  36 MODULE_SUPPORTED_DEVICE("{{ALSA,Loopback soundcard}}");
  37
  38 #define MAX_PCM_SUBSTREAMS      8
  39
  40 static int index[SNDRV_CARDS] = SNDRV_DEFAULT_IDX;      /* Index 0-MAX */
  41 static char *id[SNDRV_CARDS] = SNDRV_DEFAULT_STR;       /* ID for this card */
  42 static bool enable[SNDRV_CARDS] = {1, [1 ... (SNDRV_CARDS - 1)] = 0};
  43 static int pcm_substreams[SNDRV_CARDS] = {[0 ... (SNDRV_CARDS - 1)] = 8};
  44 static int pcm_notify[SNDRV_CARDS];
  45 static char *timer_source[SNDRV_CARDS];
  46
  47 module_param_array(index, int, NULL, 0444);
  48 MODULE_PARM_DESC(index, "Index value for loopback soundcard.");
  49 module_param_array(id, charp, NULL, 0444);
  50 MODULE_PARM_DESC(id, "ID string for loopback soundcard.");
  51 module_param_array(enable, bool, NULL, 0444);
  52 MODULE_PARM_DESC(enable, "Enable this loopback soundcard.");
  53 module_param_array(pcm_substreams, int, NULL, 0444);
  54 MODULE_PARM_DESC(pcm_substreams, "PCM substreams # (1-8) for loopback driver.");
  55 module_param_array(pcm_notify, int, NULL, 0444);
  56 MODULE_PARM_DESC(pcm_notify, "Break capture when PCM format/rate/channels changes.");
  57 module_param_array(timer_source, charp, NULL, 0444);
  58 MODULE_PARM_DESC(timer_source, "Sound card name or number and device/subdevice number of timer to be used. Empty string for jiffies timer [default].");
  59
  60 #define NO_PITCH 100000
  61
  62 #define CABLE_VALID_PLAYBACK    BIT(SNDRV_PCM_STREAM_PLAYBACK)
  63 #define CABLE_VALID_CAPTURE     BIT(SNDRV_PCM_STREAM_CAPTURE)
  64 #define CABLE_VALID_BOTH        (CABLE_VALID_PLAYBACK | CABLE_VALID_CAPTURE)
  65
  66 struct loopback_cable;
  67 struct loopback_pcm;
  68
  69 struct loopback_ops {
  70         /* optional
  71          * call in loopback->cable_lock
  72          */
  73         int (*open)(struct loopback_pcm *dpcm);
  74         /* required
  75          * call in cable->lock
  76          */
  77         int (*start)(struct loopback_pcm *dpcm);
  78         /* required
  79          * call in cable->lock
  80          */
  81         int (*stop)(struct loopback_pcm *dpcm);
  82         /* optional */
  83         int (*stop_sync)(struct loopback_pcm *dpcm);
  84         /* optional */
  85         int (*close_substream)(struct loopback_pcm *dpcm);
  86         /* optional
  87          * call in loopback->cable_lock
  88          */
  89         int (*close_cable)(struct loopback_pcm *dpcm);
  90         /* optional
  91          * call in cable->lock
  92          */
  93         unsigned int (*pos_update)(struct loopback_cable *cable);
  94         /* optional */
  95         void (*dpcm_info)(struct loopback_pcm *dpcm,
  96                           struct snd_info_buffer *buffer);
  97 };
  98
  99 struct loopback_cable {
 100         spinlock_t lock;
 101         struct loopback_pcm *streams[2];
 102         struct snd_pcm_hardware hw;
 103         /* flags */
 104         unsigned int valid;
 105         unsigned int running;
 106         unsigned int pause;
 107         /* timer specific */
 108         struct loopback_ops *ops;
 109         /* If sound timer is used */
 110         struct {
 111                 int stream;
 112                 struct snd_timer_id id;
 113                 struct tasklet_struct event_tasklet;
 114                 struct snd_timer_instance *instance;
 115         } snd_timer;
 116 };
 117
 118 struct loopback_setup {
 119         unsigned int notify: 1;
 120         unsigned int rate_shift;
 121         unsigned int format;
 122         unsigned int rate;
 123         unsigned int channels;
 124         struct snd_ctl_elem_id active_id;
 125         struct snd_ctl_elem_id format_id;
 126         struct snd_ctl_elem_id rate_id;
 127         struct snd_ctl_elem_id channels_id;
 128 };
 129
 130 struct loopback {
 131         struct snd_card *card;
 132         struct mutex cable_lock;
 133         struct loopback_cable *cables[MAX_PCM_SUBSTREAMS][2];
 134         struct snd_pcm *pcm[2];
 135         struct loopback_setup setup[MAX_PCM_SUBSTREAMS][2];
 136         const char *timer_source;
 137 };
 138
 139 struct loopback_pcm {
 140         struct loopback *loopback;
 141         struct snd_pcm_substream *substream;
 142         struct loopback_cable *cable;
 143         unsigned int pcm_buffer_size;
 144         unsigned int buf_pos;   /* position in buffer */
 145         unsigned int silent_size;
 146         /* PCM parameters */
 147         unsigned int pcm_period_size;
 148         unsigned int pcm_bps;           /* bytes per second */
 149         unsigned int pcm_salign;        /* bytes per sample * channels */
 150         unsigned int pcm_rate_shift;    /* rate shift value */
 151         /* flags */
 152         unsigned int period_update_pending :1;
 153         /* timer stuff */
 154         unsigned int irq_pos;           /* fractional IRQ position in jiffies
 155                                          * ticks
 156                                          */
 157         unsigned int period_size_frac;  /* period size in jiffies ticks */
 158         unsigned int last_drift;
 159         unsigned long last_jiffies;
 160         /* If jiffies timer is used */
 161         struct timer_list timer;
 162 };
 163
 164 static struct platform_device *devices[SNDRV_CARDS];
 165
 166 static inline unsigned int byte_pos(struct loopback_pcm *dpcm, unsigned int x)
 167 {
 168         if (dpcm->pcm_rate_shift == NO_PITCH) {
 169                 x /= HZ;
 170         } else {
 171                 x = div_u64(NO_PITCH * (unsigned long long)x,
 172                             HZ * (unsigned long long)dpcm->pcm_rate_shift);
 173         }
 174         return x - (x % dpcm->pcm_salign);
 175 }
 176
 177 static inline unsigned int frac_pos(struct loopback_pcm *dpcm, unsigned int x)
 178 {
 179         if (dpcm->pcm_rate_shift == NO_PITCH) { /* no pitch */
 180                 return x * HZ;
 181         } else {
 182                 x = div_u64(dpcm->pcm_rate_shift * (unsigned long long)x * HZ,
 183                             NO_PITCH);
 184         }
 185         return x;
 186 }
 187
 188 static inline struct loopback_setup *get_setup(struct loopback_pcm *dpcm)
 189 {
 190         int device = dpcm->substream->pstr->pcm->device;
 191
 192         if (dpcm->substream->stream == SNDRV_PCM_STREAM_PLAYBACK)
 193                 device ^= 1;
 194         return &dpcm->loopback->setup[dpcm->substream->number][device];
 195 }
 196
 197 static inline unsigned int get_notify(struct loopback_pcm *dpcm)
 198 {
 199         return get_setup(dpcm)->notify;
 200 }
 201
 202 static inline unsigned int get_rate_shift(struct loopback_pcm *dpcm)
 203 {
 204         return get_setup(dpcm)->rate_shift;
 205 }
 206
 207 /* call in cable->lock */
 208 static int loopback_jiffies_timer_start(struct loopback_pcm *dpcm)
 209 {
 210         unsigned long tick;
 211         unsigned int rate_shift = get_rate_shift(dpcm);
 212
 213         if (rate_shift != dpcm->pcm_rate_shift) {
 214                 dpcm->pcm_rate_shift = rate_shift;
 215                 dpcm->period_size_frac = frac_pos(dpcm, dpcm->pcm_period_size);
 216         }
 217         if (dpcm->period_size_frac <= dpcm->irq_pos) {
 218                 dpcm->irq_pos %= dpcm->period_size_frac;
 219                 dpcm->period_update_pending = 1;
 220         }
 221         tick = dpcm->period_size_frac - dpcm->irq_pos;
 222         tick = (tick + dpcm->pcm_bps - 1) / dpcm->pcm_bps;
 223         mod_timer(&dpcm->timer, jiffies + tick);
 224
 225         return 0;
 226 }
 227
 228 /* call in cable->lock */
 229 static int loopback_snd_timer_start(struct loopback_pcm *dpcm)
 230 {
 231         struct loopback_cable *cable = dpcm->cable;
 232         int err;
 233
 234         /* Loopback device has to use same period as timer card. Therefore
 235          * wake up for each snd_pcm_period_elapsed() call of timer card.
 236          */
 237         err = snd_timer_start(cable->snd_timer.instance, 1);
 238         if (err < 0) {
 239                 /* do not report error if trying to start but already
 240                  * running. For example called by opposite substream
 241                  * of the same cable
 242                  */
 243                 if (err == -EBUSY)
 244                         return 0;
 245
 246                 pcm_err(dpcm->substream->pcm,
 247                         "snd_timer_start(%d,%d,%d) failed with %d",
 248                         cable->snd_timer.id.card,
 249                         cable->snd_timer.id.device,
 250                         cable->snd_timer.id.subdevice,
 251                         err);
 252         }
 253
 254         return err;
 255 }
 256
 257 /* call in cable->lock */
 258 static inline int loopback_jiffies_timer_stop(struct loopback_pcm *dpcm)
 259 {
 260         del_timer(&dpcm->timer);
 261         dpcm->timer.expires = 0;
 262
 263         return 0;
 264 }
 265
 266 /* call in cable->lock */
 267 static int loopback_snd_timer_stop(struct loopback_pcm *dpcm)
 268 {
 269         struct loopback_cable *cable = dpcm->cable;
 270         int err;
 271
 272         /* only stop if both devices (playback and capture) are not running */
 273         if (cable->running ^ cable->pause)
 274                 return 0;
 275
 276         err = snd_timer_stop(cable->snd_timer.instance);
 277         if (err < 0) {
 278                 pcm_err(dpcm->substream->pcm,
 279                         "snd_timer_stop(%d,%d,%d) failed with %d",
 280                         cable->snd_timer.id.card,
 281                         cable->snd_timer.id.device,
 282                         cable->snd_timer.id.subdevice,
 283                         err);
 284         }
 285
 286         return err;
 287 }
 288
 289 static inline int loopback_jiffies_timer_stop_sync(struct loopback_pcm *dpcm)
 290 {
 291         del_timer_sync(&dpcm->timer);
 292
 293         return 0;
 294 }
 295
 296 /* call in loopback->cable_lock */
 297 static int loopback_snd_timer_close_cable(struct loopback_pcm *dpcm)
 298 {
 299         struct loopback_cable *cable = dpcm->cable;
 300
 301         /* snd_timer was not opened */
 302         if (!cable->snd_timer.instance)
 303                 return 0;
 304
 305         /* wait till drain tasklet has finished if requested */
 306         tasklet_kill(&cable->snd_timer.event_tasklet);
 307
 308         /* will only be called from free_cable() when other stream was
 309          * already closed. Other stream cannot be reopened as long as
 310          * loopback->cable_lock is locked. Therefore no need to lock
 311          * cable->lock;
 312          */
 313         snd_timer_close(cable->snd_timer.instance);
 314         snd_timer_instance_free(cable->snd_timer.instance);
 315         memset(&cable->snd_timer, 0, sizeof(cable->snd_timer));
 316
 317         return 0;
 318 }
 319
 320 static int loopback_check_format(struct loopback_cable *cable, int stream)
 321 {
 322         struct snd_pcm_runtime *runtime, *cruntime;
 323         struct loopback_setup *setup;
 324         struct snd_card *card;
 325         int check;
 326
 327         if (cable->valid != CABLE_VALID_BOTH) {
 328                 if (stream == SNDRV_PCM_STREAM_PLAYBACK)
 329                         goto __notify;
 330                 return 0;
 331         }
 332         runtime = cable->streams[SNDRV_PCM_STREAM_PLAYBACK]->
 333                                                         substream->runtime;
 334         cruntime = cable->streams[SNDRV_PCM_STREAM_CAPTURE]->
 335                                                         substream->runtime;
 336         check = runtime->format != cruntime->format ||
 337                 runtime->rate != cruntime->rate ||
 338                 runtime->channels != cruntime->channels;
 339         if (!check)
 340                 return 0;
 341         if (stream == SNDRV_PCM_STREAM_CAPTURE) {
 342                 return -EIO;
 343         } else {
 344                 snd_pcm_stop(cable->streams[SNDRV_PCM_STREAM_CAPTURE]->
 345                                         substream, SNDRV_PCM_STATE_DRAINING);
 346               __notify:
 347                 runtime = cable->streams[SNDRV_PCM_STREAM_PLAYBACK]->
 348                                                         substream->runtime;
 349                 setup = get_setup(cable->streams[SNDRV_PCM_STREAM_PLAYBACK]);
 350                 card = cable->streams[SNDRV_PCM_STREAM_PLAYBACK]->loopback->card;
 351                 if (setup->format != runtime->format) {
 352                         snd_ctl_notify(card, SNDRV_CTL_EVENT_MASK_VALUE,
 353                                                         &setup->format_id);
 354                         setup->format = runtime->format;
 355                 }
 356                 if (setup->rate != runtime->rate) {
 357                         snd_ctl_notify(card, SNDRV_CTL_EVENT_MASK_VALUE,
 358                                                         &setup->rate_id);
 359                         setup->rate = runtime->rate;
 360                 }
 361                 if (setup->channels != runtime->channels) {
 362                         snd_ctl_notify(card, SNDRV_CTL_EVENT_MASK_VALUE,
 363                                                         &setup->channels_id);
 364                         setup->channels = runtime->channels;
 365                 }
 366         }
 367         return 0;
 368 }
 369
 370 static void loopback_active_notify(struct loopback_pcm *dpcm)
 371 {
 372         snd_ctl_notify(dpcm->loopback->card,
 373                        SNDRV_CTL_EVENT_MASK_VALUE,
 374                        &get_setup(dpcm)->active_id);
 375 }
 376
 377 static int loopback_trigger(struct snd_pcm_substream *substream, int cmd)
 378 {
 379         struct snd_pcm_runtime *runtime = substream->runtime;
 380         struct loopback_pcm *dpcm = runtime->private_data;
 381         struct loopback_cable *cable = dpcm->cable;
 382         int err = 0, stream = 1 << substream->stream;
 383
 384         switch (cmd) {
 385         case SNDRV_PCM_TRIGGER_START:
 386                 err = loopback_check_format(cable, substream->stream);
 387                 if (err < 0)
 388                         return err;
 389                 dpcm->last_jiffies = jiffies;
 390                 dpcm->pcm_rate_shift = 0;
 391                 dpcm->last_drift = 0;
 392                 spin_lock(&cable->lock);
 393                 cable->running |= stream;
 394                 cable->pause &= ~stream;
 395                 err = cable->ops->start(dpcm);
 396                 spin_unlock(&cable->lock);
 397                 if (substream->stream == SNDRV_PCM_STREAM_PLAYBACK)
 398                         loopback_active_notify(dpcm);
 399                 break;
 400         case SNDRV_PCM_TRIGGER_STOP:
 401                 spin_lock(&cable->lock);
 402                 cable->running &= ~stream;
 403                 cable->pause &= ~stream;
 404                 err = cable->ops->stop(dpcm);
 405                 spin_unlock(&cable->lock);
 406                 if (substream->stream == SNDRV_PCM_STREAM_PLAYBACK)
 407                         loopback_active_notify(dpcm);
 408                 break;
 409         case SNDRV_PCM_TRIGGER_PAUSE_PUSH:
 410         case SNDRV_PCM_TRIGGER_SUSPEND:
 411                 spin_lock(&cable->lock);
 412                 cable->pause |= stream;
 413                 err = cable->ops->stop(dpcm);
 414                 spin_unlock(&cable->lock);
 415                 if (substream->stream == SNDRV_PCM_STREAM_PLAYBACK)
 416                         loopback_active_notify(dpcm);
 417                 break;
 418         case SNDRV_PCM_TRIGGER_PAUSE_RELEASE:
 419         case SNDRV_PCM_TRIGGER_RESUME:
 420                 spin_lock(&cable->lock);
 421                 dpcm->last_jiffies = jiffies;
 422                 cable->pause &= ~stream;
 423                 err = cable->ops->start(dpcm);
 424                 spin_unlock(&cable->lock);
 425                 if (substream->stream == SNDRV_PCM_STREAM_PLAYBACK)
 426                         loopback_active_notify(dpcm);
 427                 break;
 428         default:
 429                 return -EINVAL;
 430         }
 431         return err;
 432 }
 433
 434 static void params_change(struct snd_pcm_substream *substream)
 435 {
 436         struct snd_pcm_runtime *runtime = substream->runtime;
 437         struct loopback_pcm *dpcm = runtime->private_data;
 438         struct loopback_cable *cable = dpcm->cable;
 439
 440         cable->hw.formats = pcm_format_to_bits(runtime->format);
 441         cable->hw.rate_min = runtime->rate;
 442         cable->hw.rate_max = runtime->rate;
 443         cable->hw.channels_min = runtime->channels;
 444         cable->hw.channels_max = runtime->channels;
 445
 446         if (cable->snd_timer.instance) {
 447                 cable->hw.period_bytes_min =
 448                                 frames_to_bytes(runtime, runtime->period_size);
 449                 cable->hw.period_bytes_max = cable->hw.period_bytes_min;
 450         }
 451
 452 }
 453
 454 static int loopback_prepare(struct snd_pcm_substream *substream)
 455 {
 456         struct snd_pcm_runtime *runtime = substream->runtime;
 457         struct loopback_pcm *dpcm = runtime->private_data;
 458         struct loopback_cable *cable = dpcm->cable;
 459         int err, bps, salign;
 460
 461         if (cable->ops->stop_sync) {
 462                 err = cable->ops->stop_sync(dpcm);
 463                 if (err < 0)
 464                         return err;
 465         }
 466
 467         salign = (snd_pcm_format_physical_width(runtime->format) *
 468                                                 runtime->channels) / 8;
 469         bps = salign * runtime->rate;
 470         if (bps <= 0 || salign <= 0)
 471                 return -EINVAL;
 472
 473         dpcm->buf_pos = 0;
 474         dpcm->pcm_buffer_size = frames_to_bytes(runtime, runtime->buffer_size);
 475         if (substream->stream == SNDRV_PCM_STREAM_CAPTURE) {
 476                 /* clear capture buffer */
 477                 dpcm->silent_size = dpcm->pcm_buffer_size;
 478                 snd_pcm_format_set_silence(runtime->format, runtime->dma_area,
 479                                            runtime->buffer_size * runtime->channels);
 480         }
 481
 482         dpcm->irq_pos = 0;
 483         dpcm->period_update_pending = 0;
 484         dpcm->pcm_bps = bps;
 485         dpcm->pcm_salign = salign;
 486         dpcm->pcm_period_size = frames_to_bytes(runtime, runtime->period_size);
 487
 488         mutex_lock(&dpcm->loopback->cable_lock);
 489         if (!(cable->valid & ~(1 << substream->stream)) ||
 490             (get_setup(dpcm)->notify &&
 491              substream->stream == SNDRV_PCM_STREAM_PLAYBACK))
 492                 params_change(substream);
 493         cable->valid |= 1 << substream->stream;
 494         mutex_unlock(&dpcm->loopback->cable_lock);
 495
 496         return 0;
 497 }
 498
 499 static void clear_capture_buf(struct loopback_pcm *dpcm, unsigned int bytes)
 500 {
 501         struct snd_pcm_runtime *runtime = dpcm->substream->runtime;
 502         char *dst = runtime->dma_area;
 503         unsigned int dst_off = dpcm->buf_pos;
 504
 505         if (dpcm->silent_size >= dpcm->pcm_buffer_size)
 506                 return;
 507         if (dpcm->silent_size + bytes > dpcm->pcm_buffer_size)
 508                 bytes = dpcm->pcm_buffer_size - dpcm->silent_size;
 509
 510         for (;;) {
 511                 unsigned int size = bytes;
 512                 if (dst_off + size > dpcm->pcm_buffer_size)
 513                         size = dpcm->pcm_buffer_size - dst_off;
 514                 snd_pcm_format_set_silence(runtime->format, dst + dst_off,
 515                                            bytes_to_frames(runtime, size) *
 516                                                 runtime->channels);
 517                 dpcm->silent_size += size;
 518                 bytes -= size;
 519                 if (!bytes)
 520                         break;
 521                 dst_off = 0;
 522         }
 523 }
 524
 525 static void copy_play_buf(struct loopback_pcm *play,
 526                           struct loopback_pcm *capt,
 527                           unsigned int bytes)
 528 {
 529         struct snd_pcm_runtime *runtime = play->substream->runtime;
 530         char *src = runtime->dma_area;
 531         char *dst = capt->substream->runtime->dma_area;
 532         unsigned int src_off = play->buf_pos;
 533         unsigned int dst_off = capt->buf_pos;
 534         unsigned int clear_bytes = 0;
 535
 536         /* check if playback is draining, trim the capture copy size
 537          * when our pointer is at the end of playback ring buffer */
 538         if (runtime->status->state == SNDRV_PCM_STATE_DRAINING &&
 539             snd_pcm_playback_hw_avail(runtime) < runtime->buffer_size) {
 540                 snd_pcm_uframes_t appl_ptr, appl_ptr1, diff;
 541                 appl_ptr = appl_ptr1 = runtime->control->appl_ptr;
 542                 appl_ptr1 -= appl_ptr1 % runtime->buffer_size;
 543                 appl_ptr1 += play->buf_pos / play->pcm_salign;
 544                 if (appl_ptr < appl_ptr1)
 545                         appl_ptr1 -= runtime->buffer_size;
 546                 diff = (appl_ptr - appl_ptr1) * play->pcm_salign;
 547                 if (diff < bytes) {
 548                         clear_bytes = bytes - diff;
 549                         bytes = diff;
 550                 }
 551         }
 552
 553         for (;;) {
 554                 unsigned int size = bytes;
 555                 if (src_off + size > play->pcm_buffer_size)
 556                         size = play->pcm_buffer_size - src_off;
 557                 if (dst_off + size > capt->pcm_buffer_size)
 558                         size = capt->pcm_buffer_size - dst_off;
 559                 memcpy(dst + dst_off, src + src_off, size);
 560                 capt->silent_size = 0;
 561                 bytes -= size;
 562                 if (!bytes)
 563                         break;
 564                 src_off = (src_off + size) % play->pcm_buffer_size;
 565                 dst_off = (dst_off + size) % capt->pcm_buffer_size;
 566         }
 567
 568         if (clear_bytes > 0) {
 569                 clear_capture_buf(capt, clear_bytes);
 570                 capt->silent_size = 0;
 571         }
 572 }
 573
 574 static inline unsigned int bytepos_delta(struct loopback_pcm *dpcm,
 575                                          unsigned int jiffies_delta)
 576 {
 577         unsigned long last_pos;
 578         unsigned int delta;
 579
 580         last_pos = byte_pos(dpcm, dpcm->irq_pos);
 581         dpcm->irq_pos += jiffies_delta * dpcm->pcm_bps;
 582         delta = byte_pos(dpcm, dpcm->irq_pos) - last_pos;
 583         if (delta >= dpcm->last_drift)
 584                 delta -= dpcm->last_drift;
 585         dpcm->last_drift = 0;
 586         if (dpcm->irq_pos >= dpcm->period_size_frac) {
 587                 dpcm->irq_pos %= dpcm->period_size_frac;
 588                 dpcm->period_update_pending = 1;
 589         }
 590         return delta;
 591 }
 592
 593 static inline void bytepos_finish(struct loopback_pcm *dpcm,
 594                                   unsigned int delta)
 595 {
 596         dpcm->buf_pos += delta;
 597         dpcm->buf_pos %= dpcm->pcm_buffer_size;
 598 }
 599
 600 /* call in cable->lock */
 601 static unsigned int loopback_jiffies_timer_pos_update
 602                 (struct loopback_cable *cable)
 603 {
 604         struct loopback_pcm *dpcm_play =
 605                         cable->streams[SNDRV_PCM_STREAM_PLAYBACK];
 606         struct loopback_pcm *dpcm_capt =
 607                         cable->streams[SNDRV_PCM_STREAM_CAPTURE];
 608         unsigned long delta_play = 0, delta_capt = 0;
 609         unsigned int running, count1, count2;
 610
 611         running = cable->running ^ cable->pause;
 612         if (running & (1 << SNDRV_PCM_STREAM_PLAYBACK)) {
 613                 delta_play = jiffies - dpcm_play->last_jiffies;
 614                 dpcm_play->last_jiffies += delta_play;
 615         }
 616
 617         if (running & (1 << SNDRV_PCM_STREAM_CAPTURE)) {
 618                 delta_capt = jiffies - dpcm_capt->last_jiffies;
 619                 dpcm_capt->last_jiffies += delta_capt;
 620         }
 621
 622         if (delta_play == 0 && delta_capt == 0)
 623                 goto unlock;
 624
 625         if (delta_play > delta_capt) {
 626                 count1 = bytepos_delta(dpcm_play, delta_play - delta_capt);
 627                 bytepos_finish(dpcm_play, count1);
 628                 delta_play = delta_capt;
 629         } else if (delta_play < delta_capt) {
 630                 count1 = bytepos_delta(dpcm_capt, delta_capt - delta_play);
 631                 clear_capture_buf(dpcm_capt, count1);
 632                 bytepos_finish(dpcm_capt, count1);
 633                 delta_capt = delta_play;
 634         }
 635
 636         if (delta_play == 0 && delta_capt == 0)
 637                 goto unlock;
 638
 639         /* note delta_capt == delta_play at this moment */
 640         count1 = bytepos_delta(dpcm_play, delta_play);
 641         count2 = bytepos_delta(dpcm_capt, delta_capt);
 642         if (count1 < count2) {
 643                 dpcm_capt->last_drift = count2 - count1;
 644                 count1 = count2;
 645         } else if (count1 > count2) {
 646                 dpcm_play->last_drift = count1 - count2;
 647         }
 648         copy_play_buf(dpcm_play, dpcm_capt, count1);
 649         bytepos_finish(dpcm_play, count1);
 650         bytepos_finish(dpcm_capt, count1);
 651  unlock:
 652         return running;
 653 }
 654
 655 static void loopback_jiffies_timer_function(struct timer_list *t)
 656 {
 657         struct loopback_pcm *dpcm = from_timer(dpcm, t, timer);
 658         unsigned long flags;
 659
 660         spin_lock_irqsave(&dpcm->cable->lock, flags);
 661         if (loopback_jiffies_timer_pos_update(dpcm->cable) &
 662                         (1 << dpcm->substream->stream)) {
 663                 loopback_jiffies_timer_start(dpcm);
 664                 if (dpcm->period_update_pending) {
 665                         dpcm->period_update_pending = 0;
 666                         spin_unlock_irqrestore(&dpcm->cable->lock, flags);
 667                         /* need to unlock before calling below */
 668                         snd_pcm_period_elapsed(dpcm->substream);
 669                         return;
 670                 }
 671         }
 672         spin_unlock_irqrestore(&dpcm->cable->lock, flags);
 673 }
 674
 675 /* call in cable->lock */
 676 static int loopback_snd_timer_check_resolution(struct snd_pcm_runtime *runtime,
 677                                                unsigned long resolution)
 678 {
 679         if (resolution != runtime->timer_resolution) {
 680                 struct loopback_pcm *dpcm = runtime->private_data;
 681                 struct loopback_cable *cable = dpcm->cable;
 682                 /* Worst case estimation of possible values for resolution
 683                  * resolution <= (512 * 1024) frames / 8kHz in nsec
 684                  * resolution <= 65.536.000.000 nsec
 685                  *
 686                  * period_size <= 65.536.000.000 nsec / 1000nsec/usec * 192kHz +
 687                  *  500.000
 688                  * period_size <= 12.582.912.000.000  <64bit
 689                  *  / 1.000.000 usec/sec
 690                  */
 691                 snd_pcm_uframes_t period_size_usec =
 692                                 resolution / 1000 * runtime->rate;
 693                 /* round to nearest sample rate */
 694                 snd_pcm_uframes_t period_size =
 695                                 (period_size_usec + 500 * 1000) / (1000 * 1000);
 696
 697                 pcm_err(dpcm->substream->pcm,
 698                         "Period size (%lu frames) of loopback device is not corresponding to timer resolution (%lu nsec = %lu frames) of card timer %d,%d,%d. Use period size of %lu frames for loopback device.",
 699                         runtime->period_size, resolution, period_size,
 700                         cable->snd_timer.id.card,
 701                         cable->snd_timer.id.device,
 702                         cable->snd_timer.id.subdevice,
 703                         period_size);
 704                 return -EINVAL;
 705         }
 706         return 0;
 707 }
 708
 709 static void loopback_snd_timer_period_elapsed(struct loopback_cable *cable,
 710                                               int event,
 711                                               unsigned long resolution)
 712 {
 713         struct loopback_pcm *dpcm_play, *dpcm_capt;
 714         struct snd_pcm_substream *substream_play, *substream_capt;
 715         struct snd_pcm_runtime *valid_runtime;
 716         unsigned int running, elapsed_bytes;
 717         unsigned long flags;
 718
 719         spin_lock_irqsave(&cable->lock, flags);
 720         running = cable->running ^ cable->pause;
 721         /* no need to do anything if no stream is running */
 722         if (!running) {
 723                 spin_unlock_irqrestore(&cable->lock, flags);
 724                 return;
 725         }
 726
 727         dpcm_play = cable->streams[SNDRV_PCM_STREAM_PLAYBACK];
 728         dpcm_capt = cable->streams[SNDRV_PCM_STREAM_CAPTURE];
 729         substream_play = (running & (1 << SNDRV_PCM_STREAM_PLAYBACK)) ?
 730                         dpcm_play->substream : NULL;
 731         substream_capt = (running & (1 << SNDRV_PCM_STREAM_CAPTURE)) ?
 732                         dpcm_capt->substream : NULL;
 733
 734         if (event == SNDRV_TIMER_EVENT_MSTOP) {
 735                 if (!dpcm_play ||
 736                     dpcm_play->substream->runtime->status->state !=
 737                                 SNDRV_PCM_STATE_DRAINING) {
 738                         spin_unlock_irqrestore(&cable->lock, flags);
 739                         return;
 740                 }
 741         }
 742
 743         valid_runtime = (running & (1 << SNDRV_PCM_STREAM_PLAYBACK)) ?
 744                                 dpcm_play->substream->runtime :
 745                                 dpcm_capt->substream->runtime;
 746
 747         /* resolution is only valid for SNDRV_TIMER_EVENT_TICK events */
 748         if (event == SNDRV_TIMER_EVENT_TICK) {
 749                 /* The hardware rules guarantee that playback and capture period
 750                  * are the same. Therefore only one device has to be checked
 751                  * here.
 752                  */
 753                 if (loopback_snd_timer_check_resolution(valid_runtime,
 754                                                         resolution) < 0) {
 755                         spin_unlock_irqrestore(&cable->lock, flags);
 756                         if (substream_play)
 757                                 snd_pcm_stop_xrun(substream_play);
 758                         if (substream_capt)
 759                                 snd_pcm_stop_xrun(substream_capt);
 760                         return;
 761                 }
 762         }
 763
 764         elapsed_bytes = frames_to_bytes(valid_runtime,
 765                                         valid_runtime->period_size);
 766         /* The same timer interrupt is used for playback and capture device */
 767         if ((running & (1 << SNDRV_PCM_STREAM_PLAYBACK)) &&
 768             (running & (1 << SNDRV_PCM_STREAM_CAPTURE))) {
 769                 copy_play_buf(dpcm_play, dpcm_capt, elapsed_bytes);
 770                 bytepos_finish(dpcm_play, elapsed_bytes);
 771                 bytepos_finish(dpcm_capt, elapsed_bytes);
 772         } else if (running & (1 << SNDRV_PCM_STREAM_PLAYBACK)) {
 773                 bytepos_finish(dpcm_play, elapsed_bytes);
 774         } else if (running & (1 << SNDRV_PCM_STREAM_CAPTURE)) {
 775                 clear_capture_buf(dpcm_capt, elapsed_bytes);
 776                 bytepos_finish(dpcm_capt, elapsed_bytes);
 777         }
 778         spin_unlock_irqrestore(&cable->lock, flags);
 779
 780         if (substream_play)
 781                 snd_pcm_period_elapsed(substream_play);
 782         if (substream_capt)
 783                 snd_pcm_period_elapsed(substream_capt);
 784 }
 785
 786 static void loopback_snd_timer_function(struct snd_timer_instance *timeri,
 787                                         unsigned long resolution,
 788                                         unsigned long ticks)
 789 {
 790         struct loopback_cable *cable = timeri->callback_data;
 791
 792         loopback_snd_timer_period_elapsed(cable, SNDRV_TIMER_EVENT_TICK,
 793                                           resolution);
 794 }
 795
 796 static void loopback_snd_timer_tasklet(unsigned long arg)
 797 {
 798         struct snd_timer_instance *timeri = (struct snd_timer_instance *)arg;
 799         struct loopback_cable *cable = timeri->callback_data;
 800
 801         loopback_snd_timer_period_elapsed(cable, SNDRV_TIMER_EVENT_MSTOP, 0);
 802 }
 803
 804 static void loopback_snd_timer_event(struct snd_timer_instance *timeri,
 805                                      int event,
 806                                      struct timespec *tstamp,
 807                                      unsigned long resolution)
 808 {
 809         /* Do not lock cable->lock here because timer->lock is already hold.
 810          * There are other functions which first lock cable->lock and than
 811          * timer->lock e.g.
 812          * loopback_trigger()
 813          * spin_lock(&cable->lock)
 814          * loopback_snd_timer_start()
 815          * snd_timer_start()
 816          * spin_lock(&timer->lock)
 817          * Therefore when using the oposit order of locks here it could result
 818          * in a deadlock.
 819          */
 820
 821         if (event == SNDRV_TIMER_EVENT_MSTOP) {
 822                 struct loopback_cable *cable = timeri->callback_data;
 823
 824                 /* sound card of the timer was stopped. Therefore there will not
 825                  * be any further timer callbacks. Due to this forward audio
 826                  * data from here if in draining state. When still in running
 827                  * state the streaming will be aborted by the usual timeout. It
 828                  * should not be aborted here because may be the timer sound
 829                  * card does only a recovery and the timer is back soon.
 830                  * This tasklet triggers loopback_snd_timer_tasklet()
 831                  */
 832                 tasklet_schedule(&cable->snd_timer.event_tasklet);
 833         }
 834 }
 835
 836 static void loopback_jiffies_timer_dpcm_info(struct loopback_pcm *dpcm,
 837                                              struct snd_info_buffer *buffer)
 838 {
 839         snd_iprintf(buffer, "    update_pending:\t%u\n",
 840                     dpcm->period_update_pending);
 841         snd_iprintf(buffer, "    irq_pos:\t\t%u\n", dpcm->irq_pos);
 842         snd_iprintf(buffer, "    period_frac:\t%u\n", dpcm->period_size_frac);
 843         snd_iprintf(buffer, "    last_jiffies:\t%lu (%lu)\n",
 844                     dpcm->last_jiffies, jiffies);
 845         snd_iprintf(buffer, "    timer_expires:\t%lu\n", dpcm->timer.expires);
 846 }
 847
 848 static void loopback_snd_timer_dpcm_info(struct loopback_pcm *dpcm,
 849                                          struct snd_info_buffer *buffer)
 850 {
 851         struct loopback_cable *cable = dpcm->cable;
 852
 853         snd_iprintf(buffer, "    sound timer:\thw:%d,%d,%d\n",
 854                     cable->snd_timer.id.card,
 855                     cable->snd_timer.id.device,
 856                     cable->snd_timer.id.subdevice);
 857         snd_iprintf(buffer, "    timer open:\t\t%s\n",
 858                     (cable->snd_timer.stream == SNDRV_PCM_STREAM_CAPTURE) ?
 859                             "capture" : "playback");
 860 }
 861
 862 static snd_pcm_uframes_t loopback_pointer(struct snd_pcm_substream *substream)
 863 {
 864         struct snd_pcm_runtime *runtime = substream->runtime;
 865         struct loopback_pcm *dpcm = runtime->private_data;
 866         snd_pcm_uframes_t pos;
 867
 868         spin_lock(&dpcm->cable->lock);
 869         if (dpcm->cable->ops->pos_update)
 870                 dpcm->cable->ops->pos_update(dpcm->cable);
 871         pos = dpcm->buf_pos;
 872         spin_unlock(&dpcm->cable->lock);
 873         return bytes_to_frames(runtime, pos);
 874 }
 875
 876 static const struct snd_pcm_hardware loopback_pcm_hardware =
 877 {
 878         .info =         (SNDRV_PCM_INFO_INTERLEAVED | SNDRV_PCM_INFO_MMAP |
 879                          SNDRV_PCM_INFO_MMAP_VALID | SNDRV_PCM_INFO_PAUSE |
 880                          SNDRV_PCM_INFO_RESUME),
 881         .formats =      (SNDRV_PCM_FMTBIT_S16_LE | SNDRV_PCM_FMTBIT_S16_BE |
 882                          SNDRV_PCM_FMTBIT_S24_LE | SNDRV_PCM_FMTBIT_S24_BE |
 883                          SNDRV_PCM_FMTBIT_S24_3LE | SNDRV_PCM_FMTBIT_S24_3BE |
 884                          SNDRV_PCM_FMTBIT_S32_LE | SNDRV_PCM_FMTBIT_S32_BE |
 885                          SNDRV_PCM_FMTBIT_FLOAT_LE | SNDRV_PCM_FMTBIT_FLOAT_BE),
 886         .rates =        SNDRV_PCM_RATE_CONTINUOUS | SNDRV_PCM_RATE_8000_192000,
 887         .rate_min =             8000,
 888         .rate_max =             192000,
 889         .channels_min =         1,
 890         .channels_max =         32,
 891         .buffer_bytes_max =     2 * 1024 * 1024,
 892         .period_bytes_min =     64,
 893         /* note check overflow in frac_pos() using pcm_rate_shift before
 894            changing period_bytes_max value */
 895         .period_bytes_max =     1024 * 1024,
 896         .periods_min =          1,
 897         .periods_max =          1024,
 898         .fifo_size =            0,
 899 };
 900
 901 static void loopback_runtime_free(struct snd_pcm_runtime *runtime)
 902 {
 903         struct loopback_pcm *dpcm = runtime->private_data;
 904         kfree(dpcm);
 905 }
 906
 907 static int loopback_hw_params(struct snd_pcm_substream *substream,
 908                               struct snd_pcm_hw_params *params)
 909 {
 910         return snd_pcm_lib_malloc_pages(substream, params_buffer_bytes(params));
 911 }
 912
 913 static int loopback_hw_free(struct snd_pcm_substream *substream)
 914 {
 915         struct snd_pcm_runtime *runtime = substream->runtime;
 916         struct loopback_pcm *dpcm = runtime->private_data;
 917         struct loopback_cable *cable = dpcm->cable;
 918
 919         mutex_lock(&dpcm->loopback->cable_lock);
 920         cable->valid &= ~(1 << substream->stream);
 921         mutex_unlock(&dpcm->loopback->cable_lock);
 922         return snd_pcm_lib_free_pages(substream);
 923 }
 924
 925 static unsigned int get_cable_index(struct snd_pcm_substream *substream)
 926 {
 927         if (!substream->pcm->device)
 928                 return substream->stream;
 929         else
 930                 return !substream->stream;
 931 }
 932
 933 static int rule_format(struct snd_pcm_hw_params *params,
 934                        struct snd_pcm_hw_rule *rule)
 935 {
 936         struct loopback_pcm *dpcm = rule->private;
 937         struct loopback_cable *cable = dpcm->cable;
 938         struct snd_mask m;
 939
 940         snd_mask_none(&m);
 941         mutex_lock(&dpcm->loopback->cable_lock);
 942         m.bits[0] = (u_int32_t)cable->hw.formats;
 943         m.bits[1] = (u_int32_t)(cable->hw.formats >> 32);
 944         mutex_unlock(&dpcm->loopback->cable_lock);
 945         return snd_mask_refine(hw_param_mask(params, rule->var), &m);
 946 }
 947
 948 static int rule_rate(struct snd_pcm_hw_params *params,
 949                      struct snd_pcm_hw_rule *rule)
 950 {
 951         struct loopback_pcm *dpcm = rule->private;
 952         struct loopback_cable *cable = dpcm->cable;
 953         struct snd_interval t;
 954
 955         mutex_lock(&dpcm->loopback->cable_lock);
 956         t.min = cable->hw.rate_min;
 957         t.max = cable->hw.rate_max;
 958         mutex_unlock(&dpcm->loopback->cable_lock);
 959         t.openmin = t.openmax = 0;
 960         t.integer = 0;
 961         return snd_interval_refine(hw_param_interval(params, rule->var), &t);
 962 }
 963
 964 static int rule_channels(struct snd_pcm_hw_params *params,
 965                          struct snd_pcm_hw_rule *rule)
 966 {
 967         struct loopback_pcm *dpcm = rule->private;
 968         struct loopback_cable *cable = dpcm->cable;
 969         struct snd_interval t;
 970
 971         mutex_lock(&dpcm->loopback->cable_lock);
 972         t.min = cable->hw.channels_min;
 973         t.max = cable->hw.channels_max;
 974         mutex_unlock(&dpcm->loopback->cable_lock);
 975         t.openmin = t.openmax = 0;
 976         t.integer = 0;
 977         return snd_interval_refine(hw_param_interval(params, rule->var), &t);
 978 }
 979
 980 static int rule_period_bytes(struct snd_pcm_hw_params *params,
 981                              struct snd_pcm_hw_rule *rule)
 982 {
 983         struct loopback_pcm *dpcm = rule->private;
 984         struct loopback_cable *cable = dpcm->cable;
 985         struct snd_interval t;
 986
 987         mutex_lock(&dpcm->loopback->cable_lock);
 988         t.min = cable->hw.period_bytes_min;
 989         t.max = cable->hw.period_bytes_max;
 990         mutex_unlock(&dpcm->loopback->cable_lock);
 991         t.openmin = 0;
 992         t.openmax = 0;
 993         t.integer = 0;
 994         return snd_interval_refine(hw_param_interval(params, rule->var), &t);
 995 }
 996
 997 static void free_cable(struct snd_pcm_substream *substream)
 998 {
 999         struct loopback *loopback = substream->private_data;
1000         int dev = get_cable_index(substream);
1001         struct loopback_cable *cable;
1002
1003         cable = loopback->cables[substream->number][dev];
1004         if (!cable)
1005                 return;
1006         if (cable->streams[!substream->stream]) {
1007                 /* other stream is still alive */
1008                 spin_lock_irq(&cable->lock);
1009                 cable->streams[substream->stream] = NULL;
1010                 spin_unlock_irq(&cable->lock);
1011         } else {
1012                 struct loopback_pcm *dpcm = substream->runtime->private_data;
1013
1014                 if (cable->ops && cable->ops->close_cable && dpcm)
1015                         cable->ops->close_cable(dpcm);
1016                 /* free the cable */
1017                 loopback->cables[substream->number][dev] = NULL;
1018                 kfree(cable);
1019         }
1020 }
1021
1022 static int loopback_jiffies_timer_open(struct loopback_pcm *dpcm)
1023 {
1024         timer_setup(&dpcm->timer, loopback_jiffies_timer_function, 0);
1025
1026         return 0;
1027 }
1028
1029 static struct loopback_ops loopback_jiffies_timer_ops = {
1030         .open = loopback_jiffies_timer_open,
1031         .start = loopback_jiffies_timer_start,
1032         .stop = loopback_jiffies_timer_stop,
1033         .stop_sync = loopback_jiffies_timer_stop_sync,
1034         .close_substream = loopback_jiffies_timer_stop_sync,
1035         .pos_update = loopback_jiffies_timer_pos_update,
1036         .dpcm_info = loopback_jiffies_timer_dpcm_info,
1037 };
1038
1039 static int loopback_parse_timer_id(const char *str,
1040                                    struct snd_timer_id *tid)
1041 {
1042         /* [<pref>:](<card name>|<card idx>)[{.,}<dev idx>[{.,}<subdev idx>]] */
1043         const char * const sep_dev = ".,";
1044         const char * const sep_pref = ":";
1045         const char *name = str;
1046         char *sep, save = '\0';
1047         int card_idx = 0, dev = 0, subdev = 0;
1048         int err;
1049
1050         sep = strpbrk(str, sep_pref);
1051         if (sep)
1052                 name = sep + 1;
1053         sep = strpbrk(name, sep_dev);
1054         if (sep) {
1055                 save = *sep;
1056                 *sep = '\0';
1057         }
1058         err = kstrtoint(name, 0, &card_idx);
1059         if (err == -EINVAL) {
1060                 /* Must be the name, not number */
1061                 for (card_idx = 0; card_idx < snd_ecards_limit; card_idx++) {
1062                         struct snd_card *card = snd_card_ref(card_idx);
1063
1064                         if (card) {
1065                                 if (!strcmp(card->id, name))
1066                                         err = 0;
1067                                 snd_card_unref(card);
1068                         }
1069                         if (!err)
1070                                 break;
1071                 }
1072         }
1073         if (sep) {
1074                 *sep = save;
1075                 if (!err) {
1076                         char *sep2, save2 = '\0';
1077
1078                         sep2 = strpbrk(sep + 1, sep_dev);
1079                         if (sep2) {
1080                                 save2 = *sep2;
1081                                 *sep2 = '\0';
1082                         }
1083                         err = kstrtoint(sep + 1, 0, &dev);
1084                         if (sep2) {
1085                                 *sep2 = save2;
1086                                 if (!err)
1087                                         err = kstrtoint(sep2 + 1, 0, &subdev);
1088                         }
1089                 }
1090         }
1091         if (!err && tid) {
1092                 tid->card = card_idx;
1093                 tid->device = dev;
1094                 tid->subdevice = subdev;
1095         }
1096         return err;
1097 }
1098
1099 /* call in loopback->cable_lock */
1100 static int loopback_snd_timer_open(struct loopback_pcm *dpcm)
1101 {
1102         int err = 0;
1103         struct snd_timer_id tid = {
1104                 .dev_class = SNDRV_TIMER_CLASS_PCM,
1105                 .dev_sclass = SNDRV_TIMER_SCLASS_APPLICATION,
1106         };
1107         struct snd_timer_instance *timeri;
1108         struct loopback_cable *cable = dpcm->cable;
1109
1110         /* check if timer was already opened. It is only opened once
1111          * per playback and capture subdevice (aka cable).
1112          */
1113         if (cable->snd_timer.instance)
1114                 goto exit;
1115
1116         err = loopback_parse_timer_id(dpcm->loopback->timer_source, &tid);
1117         if (err < 0) {
1118                 pcm_err(dpcm->substream->pcm,
1119                         "Parsing timer source \'%s\' failed with %d",
1120                         dpcm->loopback->timer_source, err);
1121                 goto exit;
1122         }
1123
1124         cable->snd_timer.stream = dpcm->substream->stream;
1125         cable->snd_timer.id = tid;
1126
1127         timeri = snd_timer_instance_new(dpcm->loopback->card->id);
1128         if (!timeri) {
1129                 err = -ENOMEM;
1130                 goto exit;
1131         }
1132         /* The callback has to be called from another tasklet. If
1133          * SNDRV_TIMER_IFLG_FAST is specified it will be called from the
1134          * snd_pcm_period_elapsed() call of the selected sound card.
1135          * snd_pcm_period_elapsed() helds snd_pcm_stream_lock_irqsave().
1136          * Due to our callback loopback_snd_timer_function() also calls
1137          * snd_pcm_period_elapsed() which calls snd_pcm_stream_lock_irqsave().
1138          * This would end up in a dead lock.
1139          */
1140         timeri->flags |= SNDRV_TIMER_IFLG_AUTO;
1141         timeri->callback = loopback_snd_timer_function;
1142         timeri->callback_data = (void *)cable;
1143         timeri->ccallback = loopback_snd_timer_event;
1144
1145         /* initialise a tasklet used for draining */
1146         tasklet_init(&cable->snd_timer.event_tasklet,
1147                      loopback_snd_timer_tasklet, (unsigned long)timeri);
1148
1149         /* The mutex loopback->cable_lock is kept locked.
1150          * Therefore snd_timer_open() cannot be called a second time
1151          * by the other device of the same cable.
1152          * Therefore the following issue cannot happen:
1153          * [proc1] Call loopback_timer_open() ->
1154          *         Unlock cable->lock for snd_timer_close/open() call
1155          * [proc2] Call loopback_timer_open() -> snd_timer_open(),
1156          *         snd_timer_start()
1157          * [proc1] Call snd_timer_open() and overwrite running timer
1158          *         instance
1159          */
1160         err = snd_timer_open(timeri, &cable->snd_timer.id, current->pid);
1161         if (err < 0) {
1162                 pcm_err(dpcm->substream->pcm,
1163                         "snd_timer_open (%d,%d,%d) failed with %d",
1164                         cable->snd_timer.id.card,
1165                         cable->snd_timer.id.device,
1166                         cable->snd_timer.id.subdevice,
1167                         err);
1168                 snd_timer_instance_free(timeri);
1169                 goto exit;
1170         }
1171
1172         cable->snd_timer.instance = timeri;
1173
1174 exit:
1175         return err;
1176 }
1177
1178 /* stop_sync() is not required for sound timer because it does not need to be
1179  * restarted in loopback_prepare() on Xrun recovery
1180  */
1181 static struct loopback_ops loopback_snd_timer_ops = {
1182         .open = loopback_snd_timer_open,
1183         .start = loopback_snd_timer_start,
1184         .stop = loopback_snd_timer_stop,
1185         .close_cable = loopback_snd_timer_close_cable,
1186         .dpcm_info = loopback_snd_timer_dpcm_info,
1187 };
1188
1189 static int loopback_open(struct snd_pcm_substream *substream)
1190 {
1191         struct snd_pcm_runtime *runtime = substream->runtime;
1192         struct loopback *loopback = substream->private_data;
1193         struct loopback_pcm *dpcm;
1194         struct loopback_cable *cable = NULL;
1195         int err = 0;
1196         int dev = get_cable_index(substream);
1197
1198         mutex_lock(&loopback->cable_lock);
1199         dpcm = kzalloc(sizeof(*dpcm), GFP_KERNEL);
1200         if (!dpcm) {
1201                 err = -ENOMEM;
1202                 goto unlock;
1203         }
1204         dpcm->loopback = loopback;
1205         dpcm->substream = substream;
1206
1207         cable = loopback->cables[substream->number][dev];
1208         if (!cable) {
1209                 cable = kzalloc(sizeof(*cable), GFP_KERNEL);
1210                 if (!cable) {
1211                         err = -ENOMEM;
1212                         goto unlock;
1213                 }
1214                 spin_lock_init(&cable->lock);
1215                 cable->hw = loopback_pcm_hardware;
1216                 if (loopback->timer_source)
1217                         cable->ops = &loopback_snd_timer_ops;
1218                 else
1219                         cable->ops = &loopback_jiffies_timer_ops;
1220                 loopback->cables[substream->number][dev] = cable;
1221         }
1222         dpcm->cable = cable;
1223         runtime->private_data = dpcm;
1224
1225         if (cable->ops->open) {
1226                 err = cable->ops->open(dpcm);
1227                 if (err < 0)
1228                         goto unlock;
1229         }
1230
1231         snd_pcm_hw_constraint_integer(runtime, SNDRV_PCM_HW_PARAM_PERIODS);
1232
1233         /* use dynamic rules based on actual runtime->hw values */
1234         /* note that the default rules created in the PCM midlevel code */
1235         /* are cached -> they do not reflect the actual state */
1236         err = snd_pcm_hw_rule_add(runtime, 0,
1237                                   SNDRV_PCM_HW_PARAM_FORMAT,
1238                                   rule_format, dpcm,
1239                                   SNDRV_PCM_HW_PARAM_FORMAT, -1);
1240         if (err < 0)
1241                 goto unlock;
1242         err = snd_pcm_hw_rule_add(runtime, 0,
1243                                   SNDRV_PCM_HW_PARAM_RATE,
1244                                   rule_rate, dpcm,
1245                                   SNDRV_PCM_HW_PARAM_RATE, -1);
1246         if (err < 0)
1247                 goto unlock;
1248         err = snd_pcm_hw_rule_add(runtime, 0,
1249                                   SNDRV_PCM_HW_PARAM_CHANNELS,
1250                                   rule_channels, dpcm,
1251                                   SNDRV_PCM_HW_PARAM_CHANNELS, -1);
1252         if (err < 0)
1253                 goto unlock;
1254
1255         /* In case of sound timer the period time of both devices of the same
1256          * loop has to be the same.
1257          * This rule only takes effect if a sound timer was chosen
1258          */
1259         if (cable->snd_timer.instance) {
1260                 err = snd_pcm_hw_rule_add(runtime, 0,
1261                                           SNDRV_PCM_HW_PARAM_PERIOD_BYTES,
1262                                           rule_period_bytes, dpcm,
1263                                           SNDRV_PCM_HW_PARAM_PERIOD_BYTES, -1);
1264                 if (err < 0)
1265                         goto unlock;
1266         }
1267
1268         /* loopback_runtime_free() has not to be called if kfree(dpcm) was
1269          * already called here. Otherwise it will end up with a double free.
1270          */
1271         runtime->private_free = loopback_runtime_free;
1272         if (get_notify(dpcm))
1273                 runtime->hw = loopback_pcm_hardware;
1274         else
1275                 runtime->hw = cable->hw;
1276
1277         spin_lock_irq(&cable->lock);
1278         cable->streams[substream->stream] = dpcm;
1279         spin_unlock_irq(&cable->lock);
1280
1281  unlock:
1282         if (err < 0) {
1283                 free_cable(substream);
1284                 kfree(dpcm);
1285         }
1286         mutex_unlock(&loopback->cable_lock);
1287         return err;
1288 }
1289
1290 static int loopback_close(struct snd_pcm_substream *substream)
1291 {
1292         struct loopback *loopback = substream->private_data;
1293         struct loopback_pcm *dpcm = substream->runtime->private_data;
1294         int err = 0;
1295
1296         if (dpcm->cable->ops->close_substream)
1297                 err = dpcm->cable->ops->close_substream(dpcm);
1298         mutex_lock(&loopback->cable_lock);
1299         free_cable(substream);
1300         mutex_unlock(&loopback->cable_lock);
1301         return err;
1302 }
1303
1304 static const struct snd_pcm_ops loopback_pcm_ops = {
1305         .open =         loopback_open,
1306         .close =        loopback_close,
1307         .ioctl =        snd_pcm_lib_ioctl,
1308         .hw_params =    loopback_hw_params,
1309         .hw_free =      loopback_hw_free,
1310         .prepare =      loopback_prepare,
1311         .trigger =      loopback_trigger,
1312         .pointer =      loopback_pointer,
1313 };
1314
1315 static int loopback_pcm_new(struct loopback *loopback,
1316                             int device, int substreams)
1317 {
1318         struct snd_pcm *pcm;
1319         int err;
1320
1321         err = snd_pcm_new(loopback->card, "Loopback PCM", device,
1322                           substreams, substreams, &pcm);
1323         if (err < 0)
1324                 return err;
1325         snd_pcm_set_ops(pcm, SNDRV_PCM_STREAM_PLAYBACK, &loopback_pcm_ops);
1326         snd_pcm_set_ops(pcm, SNDRV_PCM_STREAM_CAPTURE, &loopback_pcm_ops);
1327         snd_pcm_lib_preallocate_pages_for_all(pcm, SNDRV_DMA_TYPE_VMALLOC,
1328                                               NULL, 0, 0);
1329
1330         pcm->private_data = loopback;
1331         pcm->info_flags = 0;
1332         strcpy(pcm->name, "Loopback PCM");
1333
1334         loopback->pcm[device] = pcm;
1335         return 0;
1336 }
1337
1338 static int loopback_rate_shift_info(struct snd_kcontrol *kcontrol,
1339                                     struct snd_ctl_elem_info *uinfo)
1340 {
1341         uinfo->type = SNDRV_CTL_ELEM_TYPE_INTEGER;
1342         uinfo->count = 1;
1343         uinfo->value.integer.min = 80000;
1344         uinfo->value.integer.max = 120000;
1345         uinfo->value.integer.step = 1;
1346         return 0;
1347 }
1348
1349 static int loopback_rate_shift_get(struct snd_kcontrol *kcontrol,
1350                                    struct snd_ctl_elem_value *ucontrol)
1351 {
1352         struct loopback *loopback = snd_kcontrol_chip(kcontrol);
1353
1354         mutex_lock(&loopback->cable_lock);
1355         ucontrol->value.integer.value[0] =
1356                 loopback->setup[kcontrol->id.subdevice]
1357                                [kcontrol->id.device].rate_shift;
1358         mutex_unlock(&loopback->cable_lock);
1359         return 0;
1360 }
1361
1362 static int loopback_rate_shift_put(struct snd_kcontrol *kcontrol,
1363                                    struct snd_ctl_elem_value *ucontrol)
1364 {
1365         struct loopback *loopback = snd_kcontrol_chip(kcontrol);
1366         unsigned int val;
1367         int change = 0;
1368
1369         val = ucontrol->value.integer.value[0];
1370         if (val < 80000)
1371                 val = 80000;
1372         if (val > 120000)
1373                 val = 120000;
1374         mutex_lock(&loopback->cable_lock);
1375         if (val != loopback->setup[kcontrol->id.subdevice]
1376                                   [kcontrol->id.device].rate_shift) {
1377                 loopback->setup[kcontrol->id.subdevice]
1378                                [kcontrol->id.device].rate_shift = val;
1379                 change = 1;
1380         }
1381         mutex_unlock(&loopback->cable_lock);
1382         return change;
1383 }
1384
1385 static int loopback_notify_get(struct snd_kcontrol *kcontrol,
1386                                struct snd_ctl_elem_value *ucontrol)
1387 {
1388         struct loopback *loopback = snd_kcontrol_chip(kcontrol);
1389
1390         mutex_lock(&loopback->cable_lock);
1391         ucontrol->value.integer.value[0] =
1392                 loopback->setup[kcontrol->id.subdevice]
1393                                [kcontrol->id.device].notify;
1394         mutex_unlock(&loopback->cable_lock);
1395         return 0;
1396 }
1397
1398 static int loopback_notify_put(struct snd_kcontrol *kcontrol,
1399                                struct snd_ctl_elem_value *ucontrol)
1400 {
1401         struct loopback *loopback = snd_kcontrol_chip(kcontrol);
1402         unsigned int val;
1403         int change = 0;
1404
1405         val = ucontrol->value.integer.value[0] ? 1 : 0;
1406         mutex_lock(&loopback->cable_lock);
1407         if (val != loopback->setup[kcontrol->id.subdevice]
1408                                 [kcontrol->id.device].notify) {
1409                 loopback->setup[kcontrol->id.subdevice]
1410                         [kcontrol->id.device].notify = val;
1411                 change = 1;
1412         }
1413         mutex_unlock(&loopback->cable_lock);
1414         return change;
1415 }
1416
1417 static int loopback_active_get(struct snd_kcontrol *kcontrol,
1418                                struct snd_ctl_elem_value *ucontrol)
1419 {
1420         struct loopback *loopback = snd_kcontrol_chip(kcontrol);
1421         struct loopback_cable *cable;
1422
1423         unsigned int val = 0;
1424
1425         mutex_lock(&loopback->cable_lock);
1426         cable = loopback->cables[kcontrol->id.subdevice][kcontrol->id.device ^ 1];
1427         if (cable != NULL) {
1428                 unsigned int running = cable->running ^ cable->pause;
1429
1430                 val = (running & (1 << SNDRV_PCM_STREAM_PLAYBACK)) ? 1 : 0;
1431         }
1432         mutex_unlock(&loopback->cable_lock);
1433         ucontrol->value.integer.value[0] = val;
1434         return 0;
1435 }
1436
1437 static int loopback_format_info(struct snd_kcontrol *kcontrol,
1438                                 struct snd_ctl_elem_info *uinfo)
1439 {
1440         uinfo->type = SNDRV_CTL_ELEM_TYPE_INTEGER;
1441         uinfo->count = 1;
1442         uinfo->value.integer.min = 0;
1443         uinfo->value.integer.max = SNDRV_PCM_FORMAT_LAST;
1444         uinfo->value.integer.step = 1;
1445         return 0;
1446 }
1447
1448 static int loopback_format_get(struct snd_kcontrol *kcontrol,
1449                                struct snd_ctl_elem_value *ucontrol)
1450 {
1451         struct loopback *loopback = snd_kcontrol_chip(kcontrol);
1452
1453         ucontrol->value.integer.value[0] =
1454                 loopback->setup[kcontrol->id.subdevice]
1455                                [kcontrol->id.device].format;
1456         return 0;
1457 }
1458
1459 static int loopback_rate_info(struct snd_kcontrol *kcontrol,
1460                               struct snd_ctl_elem_info *uinfo)
1461 {
1462         uinfo->type = SNDRV_CTL_ELEM_TYPE_INTEGER;
1463         uinfo->count = 1;
1464         uinfo->value.integer.min = 0;
1465         uinfo->value.integer.max = 192000;
1466         uinfo->value.integer.step = 1;
1467         return 0;
1468 }
1469
1470 static int loopback_rate_get(struct snd_kcontrol *kcontrol,
1471                              struct snd_ctl_elem_value *ucontrol)
1472 {
1473         struct loopback *loopback = snd_kcontrol_chip(kcontrol);
1474
1475         mutex_lock(&loopback->cable_lock);
1476         ucontrol->value.integer.value[0] =
1477                 loopback->setup[kcontrol->id.subdevice]
1478                                [kcontrol->id.device].rate;
1479         mutex_unlock(&loopback->cable_lock);
1480         return 0;
1481 }
1482
1483 static int loopback_channels_info(struct snd_kcontrol *kcontrol,
1484                                   struct snd_ctl_elem_info *uinfo)
1485 {
1486         uinfo->type = SNDRV_CTL_ELEM_TYPE_INTEGER;
1487         uinfo->count = 1;
1488         uinfo->value.integer.min = 1;
1489         uinfo->value.integer.max = 1024;
1490         uinfo->value.integer.step = 1;
1491         return 0;
1492 }
1493
1494 static int loopback_channels_get(struct snd_kcontrol *kcontrol,
1495                                  struct snd_ctl_elem_value *ucontrol)
1496 {
1497         struct loopback *loopback = snd_kcontrol_chip(kcontrol);
1498
1499         mutex_lock(&loopback->cable_lock);
1500         ucontrol->value.integer.value[0] =
1501                 loopback->setup[kcontrol->id.subdevice]
1502                                [kcontrol->id.device].channels;
1503         mutex_unlock(&loopback->cable_lock);
1504         return 0;
1505 }
1506
1507 static struct snd_kcontrol_new loopback_controls[]  = {
1508 {
1509         .iface =        SNDRV_CTL_ELEM_IFACE_PCM,
1510         .name =         "PCM Rate Shift 100000",
1511         .info =         loopback_rate_shift_info,
1512         .get =          loopback_rate_shift_get,
1513         .put =          loopback_rate_shift_put,
1514 },
1515 {
1516         .iface =        SNDRV_CTL_ELEM_IFACE_PCM,
1517         .name =         "PCM Notify",
1518         .info =         snd_ctl_boolean_mono_info,
1519         .get =          loopback_notify_get,
1520         .put =          loopback_notify_put,
1521 },
1522 #define ACTIVE_IDX 2
1523 {
1524         .access =       SNDRV_CTL_ELEM_ACCESS_READ,
1525         .iface =        SNDRV_CTL_ELEM_IFACE_PCM,
1526         .name =         "PCM Slave Active",
1527         .info =         snd_ctl_boolean_mono_info,
1528         .get =          loopback_active_get,
1529 },
1530 #define FORMAT_IDX 3
1531 {
1532         .access =       SNDRV_CTL_ELEM_ACCESS_READ,
1533         .iface =        SNDRV_CTL_ELEM_IFACE_PCM,
1534         .name =         "PCM Slave Format",
1535         .info =         loopback_format_info,
1536         .get =          loopback_format_get
1537 },
1538 #define RATE_IDX 4
1539 {
1540         .access =       SNDRV_CTL_ELEM_ACCESS_READ,
1541         .iface =        SNDRV_CTL_ELEM_IFACE_PCM,
1542         .name =         "PCM Slave Rate",
1543         .info =         loopback_rate_info,
1544         .get =          loopback_rate_get
1545 },
1546 #define CHANNELS_IDX 5
1547 {
1548         .access =       SNDRV_CTL_ELEM_ACCESS_READ,
1549         .iface =        SNDRV_CTL_ELEM_IFACE_PCM,
1550         .name =         "PCM Slave Channels",
1551         .info =         loopback_channels_info,
1552         .get =          loopback_channels_get
1553 }
1554 };
1555
1556 static int loopback_mixer_new(struct loopback *loopback, int notify)
1557 {
1558         struct snd_card *card = loopback->card;
1559         struct snd_pcm *pcm;
1560         struct snd_kcontrol *kctl;
1561         struct loopback_setup *setup;
1562         int err, dev, substr, substr_count, idx;
1563
1564         strcpy(card->mixername, "Loopback Mixer");
1565         for (dev = 0; dev < 2; dev++) {
1566                 pcm = loopback->pcm[dev];
1567                 substr_count =
1568                     pcm->streams[SNDRV_PCM_STREAM_CAPTURE].substream_count;
1569                 for (substr = 0; substr < substr_count; substr++) {
1570                         setup = &loopback->setup[substr][dev];
1571                         setup->notify = notify;
1572                         setup->rate_shift = NO_PITCH;
1573                         setup->format = SNDRV_PCM_FORMAT_S16_LE;
1574                         setup->rate = 48000;
1575                         setup->channels = 2;
1576                         for (idx = 0; idx < ARRAY_SIZE(loopback_controls);
1577                                                                         idx++) {
1578                                 kctl = snd_ctl_new1(&loopback_controls[idx],
1579                                                     loopback);
1580                                 if (!kctl)
1581                                         return -ENOMEM;
1582                                 kctl->id.device = dev;
1583                                 kctl->id.subdevice = substr;
1584                                 switch (idx) {
1585                                 case ACTIVE_IDX:
1586                                         setup->active_id = kctl->id;
1587                                         break;
1588                                 case FORMAT_IDX:
1589                                         setup->format_id = kctl->id;
1590                                         break;
1591                                 case RATE_IDX:
1592                                         setup->rate_id = kctl->id;
1593                                         break;
1594                                 case CHANNELS_IDX:
1595                                         setup->channels_id = kctl->id;
1596                                         break;
1597                                 default:
1598                                         break;
1599                                 }
1600                                 err = snd_ctl_add(card, kctl);
1601                                 if (err < 0)
1602                                         return err;
1603                         }
1604                 }
1605         }
1606         return 0;
1607 }
1608
1609 static void print_dpcm_info(struct snd_info_buffer *buffer,
1610                             struct loopback_pcm *dpcm,
1611                             const char *id)
1612 {
1613         snd_iprintf(buffer, "  %s\n", id);
1614         if (dpcm == NULL) {
1615                 snd_iprintf(buffer, "    inactive\n");
1616                 return;
1617         }
1618         snd_iprintf(buffer, "    buffer_size:\t%u\n", dpcm->pcm_buffer_size);
1619         snd_iprintf(buffer, "    buffer_pos:\t\t%u\n", dpcm->buf_pos);
1620         snd_iprintf(buffer, "    silent_size:\t%u\n", dpcm->silent_size);
1621         snd_iprintf(buffer, "    period_size:\t%u\n", dpcm->pcm_period_size);
1622         snd_iprintf(buffer, "    bytes_per_sec:\t%u\n", dpcm->pcm_bps);
1623         snd_iprintf(buffer, "    sample_align:\t%u\n", dpcm->pcm_salign);
1624         snd_iprintf(buffer, "    rate_shift:\t\t%u\n", dpcm->pcm_rate_shift);
1625         if (dpcm->cable->ops->dpcm_info)
1626                 dpcm->cable->ops->dpcm_info(dpcm, buffer);
1627 }
1628
1629 static void print_substream_info(struct snd_info_buffer *buffer,
1630                                  struct loopback *loopback,
1631                                  int sub,
1632                                  int num)
1633 {
1634         struct loopback_cable *cable = loopback->cables[sub][num];
1635
1636         snd_iprintf(buffer, "Cable %i substream %i:\n", num, sub);
1637         if (cable == NULL) {
1638                 snd_iprintf(buffer, "  inactive\n");
1639                 return;
1640         }
1641         snd_iprintf(buffer, "  valid: %u\n", cable->valid);
1642         snd_iprintf(buffer, "  running: %u\n", cable->running);
1643         snd_iprintf(buffer, "  pause: %u\n", cable->pause);
1644         print_dpcm_info(buffer, cable->streams[0], "Playback");
1645         print_dpcm_info(buffer, cable->streams[1], "Capture");
1646 }
1647
1648 static void print_cable_info(struct snd_info_entry *entry,
1649                              struct snd_info_buffer *buffer)
1650 {
1651         struct loopback *loopback = entry->private_data;
1652         int sub, num;
1653
1654         mutex_lock(&loopback->cable_lock);
1655         num = entry->name[strlen(entry->name)-1];
1656         num = num == '0' ? 0 : 1;
1657         for (sub = 0; sub < MAX_PCM_SUBSTREAMS; sub++)
1658                 print_substream_info(buffer, loopback, sub, num);
1659         mutex_unlock(&loopback->cable_lock);
1660 }
1661
1662 static int loopback_cable_proc_new(struct loopback *loopback, int cidx)
1663 {
1664         char name[32];
1665
1666         snprintf(name, sizeof(name), "cable#%d", cidx);
1667         return snd_card_ro_proc_new(loopback->card, name, loopback,
1668                                     print_cable_info);
1669 }
1670
1671 static void loopback_set_timer_source(struct loopback *loopback,
1672                                       const char *value)
1673 {
1674         if (loopback->timer_source) {
1675                 devm_kfree(loopback->card->dev, loopback->timer_source);
1676                 loopback->timer_source = NULL;
1677         }
1678         if (value && *value)
1679                 loopback->timer_source = devm_kstrdup(loopback->card->dev,
1680                                                       value, GFP_KERNEL);
1681 }
1682
1683 static void print_timer_source_info(struct snd_info_entry *entry,
1684                                     struct snd_info_buffer *buffer)
1685 {
1686         struct loopback *loopback = entry->private_data;
1687
1688         mutex_lock(&loopback->cable_lock);
1689         snd_iprintf(buffer, "%s\n",
1690                     loopback->timer_source ? loopback->timer_source : "");
1691         mutex_unlock(&loopback->cable_lock);
1692 }
1693
1694 static void change_timer_source_info(struct snd_info_entry *entry,
1695                                      struct snd_info_buffer *buffer)
1696 {
1697         struct loopback *loopback = entry->private_data;
1698         char line[64];
1699
1700         mutex_lock(&loopback->cable_lock);
1701         if (!snd_info_get_line(buffer, line, sizeof(line)))
1702                 loopback_set_timer_source(loopback, strim(line));
1703         mutex_unlock(&loopback->cable_lock);
1704 }
1705
1706 static int loopback_timer_source_proc_new(struct loopback *loopback)
1707 {
1708         return snd_card_rw_proc_new(loopback->card, "timer_source", loopback,
1709                                     print_timer_source_info,
1710                                     change_timer_source_info);
1711 }
1712
1713 static int loopback_probe(struct platform_device *devptr)
1714 {
1715         struct snd_card *card;
1716         struct loopback *loopback;
1717         int dev = devptr->id;
1718         int err;
1719
1720         err = snd_card_new(&devptr->dev, index[dev], id[dev], THIS_MODULE,
1721                            sizeof(struct loopback), &card);
1722         if (err < 0)
1723                 return err;
1724         loopback = card->private_data;
1725
1726         if (pcm_substreams[dev] < 1)
1727                 pcm_substreams[dev] = 1;
1728         if (pcm_substreams[dev] > MAX_PCM_SUBSTREAMS)
1729                 pcm_substreams[dev] = MAX_PCM_SUBSTREAMS;
1730
1731         loopback->card = card;
1732         loopback_set_timer_source(loopback, timer_source[dev]);
1733
1734         mutex_init(&loopback->cable_lock);
1735
1736         err = loopback_pcm_new(loopback, 0, pcm_substreams[dev]);
1737         if (err < 0)
1738                 goto __nodev;
1739         err = loopback_pcm_new(loopback, 1, pcm_substreams[dev]);
1740         if (err < 0)
1741                 goto __nodev;
1742         err = loopback_mixer_new(loopback, pcm_notify[dev] ? 1 : 0);
1743         if (err < 0)
1744                 goto __nodev;
1745         loopback_cable_proc_new(loopback, 0);
1746         loopback_cable_proc_new(loopback, 1);
1747         loopback_timer_source_proc_new(loopback);
1748         strcpy(card->driver, "Loopback");
1749         strcpy(card->shortname, "Loopback");
1750         sprintf(card->longname, "Loopback %i", dev + 1);
1751         err = snd_card_register(card);
1752         if (!err) {
1753                 platform_set_drvdata(devptr, card);
1754                 return 0;
1755         }
1756       __nodev:
1757         snd_card_free(card);
1758         return err;
1759 }
1760
1761 static int loopback_remove(struct platform_device *devptr)
1762 {
1763         snd_card_free(platform_get_drvdata(devptr));
1764         return 0;
1765 }
1766
1767 #ifdef CONFIG_PM_SLEEP
1768 static int loopback_suspend(struct device *pdev)
1769 {
1770         struct snd_card *card = dev_get_drvdata(pdev);
1771
1772         snd_power_change_state(card, SNDRV_CTL_POWER_D3hot);
1773         return 0;
1774 }
1775
1776 static int loopback_resume(struct device *pdev)
1777 {
1778         struct snd_card *card = dev_get_drvdata(pdev);
1779
1780         snd_power_change_state(card, SNDRV_CTL_POWER_D0);
1781         return 0;
1782 }
1783
1784 static SIMPLE_DEV_PM_OPS(loopback_pm, loopback_suspend, loopback_resume);
1785 #define LOOPBACK_PM_OPS &loopback_pm
1786 #else
1787 #define LOOPBACK_PM_OPS NULL
1788 #endif
1789
1790 #define SND_LOOPBACK_DRIVER     "snd_aloop"
1791
1792 static struct platform_driver loopback_driver = {
1793         .probe          = loopback_probe,
1794         .remove         = loopback_remove,
1795         .driver         = {
1796                 .name   = SND_LOOPBACK_DRIVER,
1797                 .pm     = LOOPBACK_PM_OPS,
1798         },
1799 };
1800
1801 static void loopback_unregister_all(void)
1802 {
1803         int i;
1804
1805         for (i = 0; i < ARRAY_SIZE(devices); ++i)
1806                 platform_device_unregister(devices[i]);
1807         platform_driver_unregister(&loopback_driver);
1808 }
1809
1810 static int __init alsa_card_loopback_init(void)
1811 {
1812         int i, err, cards;
1813
1814         err = platform_driver_register(&loopback_driver);
1815         if (err < 0)
1816                 return err;
1817
1818
1819         cards = 0;
1820         for (i = 0; i < SNDRV_CARDS; i++) {
1821                 struct platform_device *device;
1822                 if (!enable[i])
1823                         continue;
1824                 device = platform_device_register_simple(SND_LOOPBACK_DRIVER,
1825                                                          i, NULL, 0);
1826                 if (IS_ERR(device))
1827                         continue;
1828                 if (!platform_get_drvdata(device)) {
1829                         platform_device_unregister(device);
1830                         continue;
1831                 }
1832                 devices[i] = device;
1833                 cards++;
1834         }
1835         if (!cards) {
1836 #ifdef MODULE
1837                 printk(KERN_ERR "aloop: No loopback enabled\n");
1838 #endif
1839                 loopback_unregister_all();
1840                 return -ENODEV;
1841         }
1842         return 0;
1843 }
1844
1845 static void __exit alsa_card_loopback_exit(void)
1846 {
1847         loopback_unregister_all();
1848 }
1849
1850 module_init(alsa_card_loopback_init)
1851 module_exit(alsa_card_loopback_exit)