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
  37 #define MAX_PCM_SUBSTREAMS      8
  38
  39 static int index[SNDRV_CARDS] = SNDRV_DEFAULT_IDX;      /* Index 0-MAX */
  40 static char *id[SNDRV_CARDS] = SNDRV_DEFAULT_STR;       /* ID for this card */
  41 static bool enable[SNDRV_CARDS] = {1, [1 ... (SNDRV_CARDS - 1)] = 0};
  42 static int pcm_substreams[SNDRV_CARDS] = {[0 ... (SNDRV_CARDS - 1)] = 8};
  43 static int pcm_notify[SNDRV_CARDS];
  44 static char *timer_source[SNDRV_CARDS];
  45
  46 module_param_array(index, int, NULL, 0444);
  47 MODULE_PARM_DESC(index, "Index value for loopback soundcard.");
  48 module_param_array(id, charp, NULL, 0444);
  49 MODULE_PARM_DESC(id, "ID string for loopback soundcard.");
  50 module_param_array(enable, bool, NULL, 0444);
  51 MODULE_PARM_DESC(enable, "Enable this loopback soundcard.");
  52 module_param_array(pcm_substreams, int, NULL, 0444);
  53 MODULE_PARM_DESC(pcm_substreams, "PCM substreams # (1-8) for loopback driver.");
  54 module_param_array(pcm_notify, int, NULL, 0444);
  55 MODULE_PARM_DESC(pcm_notify, "Break capture when PCM format/rate/channels changes.");
  56 module_param_array(timer_source, charp, NULL, 0444);
  57 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].");
  58
  59 #define NO_PITCH 100000
  60
  61 #define CABLE_VALID_PLAYBACK    BIT(SNDRV_PCM_STREAM_PLAYBACK)
  62 #define CABLE_VALID_CAPTURE     BIT(SNDRV_PCM_STREAM_CAPTURE)
  63 #define CABLE_VALID_BOTH        (CABLE_VALID_PLAYBACK | CABLE_VALID_CAPTURE)
  64
  65 struct loopback_cable;
  66 struct loopback_pcm;
  67
  68 struct loopback_ops {
  69         /* optional
  70          * call in loopback->cable_lock
  71          */
  72         int (*open)(struct loopback_pcm *dpcm);
  73         /* required
  74          * call in cable->lock
  75          */
  76         int (*start)(struct loopback_pcm *dpcm);
  77         /* required
  78          * call in cable->lock
  79          */
  80         int (*stop)(struct loopback_pcm *dpcm);
  81         /* optional */
  82         int (*stop_sync)(struct loopback_pcm *dpcm);
  83         /* optional */
  84         int (*close_substream)(struct loopback_pcm *dpcm);
  85         /* optional
  86          * call in loopback->cable_lock
  87          */
  88         int (*close_cable)(struct loopback_pcm *dpcm);
  89         /* optional
  90          * call in cable->lock
  91          */
  92         unsigned int (*pos_update)(struct loopback_cable *cable);
  93         /* optional */
  94         void (*dpcm_info)(struct loopback_pcm *dpcm,
  95                           struct snd_info_buffer *buffer);
  96 };
  97
  98 struct loopback_cable {
  99         spinlock_t lock;
 100         struct loopback_pcm *streams[2];
 101         struct snd_pcm_hardware hw;
 102         /* flags */
 103         unsigned int valid;
 104         unsigned int running;
 105         unsigned int pause;
 106         /* timer specific */
 107         const struct loopback_ops *ops;
 108         /* If sound timer is used */
 109         struct {
 110                 int stream;
 111                 struct snd_timer_id id;
 112                 struct work_struct event_work;
 113                 struct snd_timer_instance *instance;
 114         } snd_timer;
 115 };
 116
 117 struct loopback_setup {
 118         unsigned int notify: 1;
 119         unsigned int rate_shift;
 120         snd_pcm_format_t format;
 121         unsigned int rate;
 122         snd_pcm_access_t access;
 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         struct snd_ctl_elem_id access_id;
 129 };
 130
 131 struct loopback {
 132         struct snd_card *card;
 133         struct mutex cable_lock;
 134         struct loopback_cable *cables[MAX_PCM_SUBSTREAMS][2];
 135         struct snd_pcm *pcm[2];
 136         struct loopback_setup setup[MAX_PCM_SUBSTREAMS][2];
 137         const char *timer_source;
 138 };
 139
 140 struct loopback_pcm {
 141         struct loopback *loopback;
 142         struct snd_pcm_substream *substream;
 143         struct loopback_cable *cable;
 144         unsigned int pcm_buffer_size;
 145         unsigned int buf_pos;   /* position in buffer */
 146         unsigned int silent_size;
 147         /* PCM parameters */
 148         unsigned int pcm_period_size;
 149         unsigned int pcm_bps;           /* bytes per second */
 150         unsigned int pcm_salign;        /* bytes per sample * channels */
 151         unsigned int pcm_rate_shift;    /* rate shift value */
 152         /* flags */
 153         unsigned int period_update_pending :1;
 154         /* timer stuff */
 155         unsigned int irq_pos;           /* fractional IRQ position in jiffies
 156                                          * ticks
 157                                          */
 158         unsigned int period_size_frac;  /* period size in jiffies ticks */
 159         unsigned int last_drift;
 160         unsigned long last_jiffies;
 161         /* If jiffies timer is used */
 162         struct timer_list timer;
 163
 164         /* size of per channel buffer in case of non-interleaved access */
 165         unsigned int channel_buf_n;
 166 };
 167
 168 static struct platform_device *devices[SNDRV_CARDS];
 169
 170 static inline unsigned int byte_pos(struct loopback_pcm *dpcm, unsigned int x)
 171 {
 172         if (dpcm->pcm_rate_shift == NO_PITCH) {
 173                 x /= HZ;
 174         } else {
 175                 x = div_u64(NO_PITCH * (unsigned long long)x,
 176                             HZ * (unsigned long long)dpcm->pcm_rate_shift);
 177         }
 178         return x - (x % dpcm->pcm_salign);
 179 }
 180
 181 static inline unsigned int frac_pos(struct loopback_pcm *dpcm, unsigned int x)
 182 {
 183         if (dpcm->pcm_rate_shift == NO_PITCH) { /* no pitch */
 184                 return x * HZ;
 185         } else {
 186                 x = div_u64(dpcm->pcm_rate_shift * (unsigned long long)x * HZ,
 187                             NO_PITCH);
 188         }
 189         return x;
 190 }
 191
 192 static inline struct loopback_setup *get_setup(struct loopback_pcm *dpcm)
 193 {
 194         int device = dpcm->substream->pstr->pcm->device;
 195
 196         if (dpcm->substream->stream == SNDRV_PCM_STREAM_PLAYBACK)
 197                 device ^= 1;
 198         return &dpcm->loopback->setup[dpcm->substream->number][device];
 199 }
 200
 201 static inline unsigned int get_notify(struct loopback_pcm *dpcm)
 202 {
 203         return get_setup(dpcm)->notify;
 204 }
 205
 206 static inline unsigned int get_rate_shift(struct loopback_pcm *dpcm)
 207 {
 208         return get_setup(dpcm)->rate_shift;
 209 }
 210
 211 /* call in cable->lock */
 212 static int loopback_jiffies_timer_start(struct loopback_pcm *dpcm)
 213 {
 214         unsigned long tick;
 215         unsigned int rate_shift = get_rate_shift(dpcm);
 216
 217         if (rate_shift != dpcm->pcm_rate_shift) {
 218                 dpcm->pcm_rate_shift = rate_shift;
 219                 dpcm->period_size_frac = frac_pos(dpcm, dpcm->pcm_period_size);
 220         }
 221         if (dpcm->period_size_frac <= dpcm->irq_pos) {
 222                 dpcm->irq_pos %= dpcm->period_size_frac;
 223                 dpcm->period_update_pending = 1;
 224         }
 225         tick = dpcm->period_size_frac - dpcm->irq_pos;
 226         tick = DIV_ROUND_UP(tick, dpcm->pcm_bps);
 227         mod_timer(&dpcm->timer, jiffies + tick);
 228
 229         return 0;
 230 }
 231
 232 /* call in cable->lock */
 233 static int loopback_snd_timer_start(struct loopback_pcm *dpcm)
 234 {
 235         struct loopback_cable *cable = dpcm->cable;
 236         int err;
 237
 238         /* Loopback device has to use same period as timer card. Therefore
 239          * wake up for each snd_pcm_period_elapsed() call of timer card.
 240          */
 241         err = snd_timer_start(cable->snd_timer.instance, 1);
 242         if (err < 0) {
 243                 /* do not report error if trying to start but already
 244                  * running. For example called by opposite substream
 245                  * of the same cable
 246                  */
 247                 if (err == -EBUSY)
 248                         return 0;
 249
 250                 pcm_err(dpcm->substream->pcm,
 251                         "snd_timer_start(%d,%d,%d) failed with %d",
 252                         cable->snd_timer.id.card,
 253                         cable->snd_timer.id.device,
 254                         cable->snd_timer.id.subdevice,
 255                         err);
 256         }
 257
 258         return err;
 259 }
 260
 261 /* call in cable->lock */
 262 static inline int loopback_jiffies_timer_stop(struct loopback_pcm *dpcm)
 263 {
 264         del_timer(&dpcm->timer);
 265         dpcm->timer.expires = 0;
 266
 267         return 0;
 268 }
 269
 270 /* call in cable->lock */
 271 static int loopback_snd_timer_stop(struct loopback_pcm *dpcm)
 272 {
 273         struct loopback_cable *cable = dpcm->cable;
 274         int err;
 275
 276         /* only stop if both devices (playback and capture) are not running */
 277         if (cable->running ^ cable->pause)
 278                 return 0;
 279
 280         err = snd_timer_stop(cable->snd_timer.instance);
 281         if (err < 0) {
 282                 pcm_err(dpcm->substream->pcm,
 283                         "snd_timer_stop(%d,%d,%d) failed with %d",
 284                         cable->snd_timer.id.card,
 285                         cable->snd_timer.id.device,
 286                         cable->snd_timer.id.subdevice,
 287                         err);
 288         }
 289
 290         return err;
 291 }
 292
 293 static inline int loopback_jiffies_timer_stop_sync(struct loopback_pcm *dpcm)
 294 {
 295         del_timer_sync(&dpcm->timer);
 296
 297         return 0;
 298 }
 299
 300 /* call in loopback->cable_lock */
 301 static int loopback_snd_timer_close_cable(struct loopback_pcm *dpcm)
 302 {
 303         struct loopback_cable *cable = dpcm->cable;
 304
 305         /* snd_timer was not opened */
 306         if (!cable->snd_timer.instance)
 307                 return 0;
 308
 309         /* will only be called from free_cable() when other stream was
 310          * already closed. Other stream cannot be reopened as long as
 311          * loopback->cable_lock is locked. Therefore no need to lock
 312          * cable->lock;
 313          */
 314         snd_timer_close(cable->snd_timer.instance);
 315
 316         /* wait till drain work has finished if requested */
 317         cancel_work_sync(&cable->snd_timer.event_work);
 318
 319         snd_timer_instance_free(cable->snd_timer.instance);
 320         memset(&cable->snd_timer, 0, sizeof(cable->snd_timer));
 321
 322         return 0;
 323 }
 324
 325 static bool is_access_interleaved(snd_pcm_access_t access)
 326 {
 327         switch (access) {
 328         case SNDRV_PCM_ACCESS_MMAP_INTERLEAVED:
 329         case SNDRV_PCM_ACCESS_RW_INTERLEAVED:
 330                 return true;
 331         default:
 332                 return false;
 333         }
 334 };
 335
 336 static int loopback_check_format(struct loopback_cable *cable, int stream)
 337 {
 338         struct snd_pcm_runtime *runtime, *cruntime;
 339         struct loopback_setup *setup;
 340         struct snd_card *card;
 341         int check;
 342
 343         if (cable->valid != CABLE_VALID_BOTH) {
 344                 if (stream == SNDRV_PCM_STREAM_PLAYBACK)
 345                         goto __notify;
 346                 return 0;
 347         }
 348         runtime = cable->streams[SNDRV_PCM_STREAM_PLAYBACK]->
 349                                                         substream->runtime;
 350         cruntime = cable->streams[SNDRV_PCM_STREAM_CAPTURE]->
 351                                                         substream->runtime;
 352         check = runtime->format != cruntime->format ||
 353                 runtime->rate != cruntime->rate ||
 354                 runtime->channels != cruntime->channels ||
 355                 is_access_interleaved(runtime->access) !=
 356                 is_access_interleaved(cruntime->access);
 357         if (!check)
 358                 return 0;
 359         if (stream == SNDRV_PCM_STREAM_CAPTURE) {
 360                 return -EIO;
 361         } else {
 362                 snd_pcm_stop(cable->streams[SNDRV_PCM_STREAM_CAPTURE]->
 363                                         substream, SNDRV_PCM_STATE_DRAINING);
 364               __notify:
 365                 runtime = cable->streams[SNDRV_PCM_STREAM_PLAYBACK]->
 366                                                         substream->runtime;
 367                 setup = get_setup(cable->streams[SNDRV_PCM_STREAM_PLAYBACK]);
 368                 card = cable->streams[SNDRV_PCM_STREAM_PLAYBACK]->loopback->card;
 369                 if (setup->format != runtime->format) {
 370                         snd_ctl_notify(card, SNDRV_CTL_EVENT_MASK_VALUE,
 371                                                         &setup->format_id);
 372                         setup->format = runtime->format;
 373                 }
 374                 if (setup->rate != runtime->rate) {
 375                         snd_ctl_notify(card, SNDRV_CTL_EVENT_MASK_VALUE,
 376                                                         &setup->rate_id);
 377                         setup->rate = runtime->rate;
 378                 }
 379                 if (setup->channels != runtime->channels) {
 380                         snd_ctl_notify(card, SNDRV_CTL_EVENT_MASK_VALUE,
 381                                                         &setup->channels_id);
 382                         setup->channels = runtime->channels;
 383                 }
 384                 if (is_access_interleaved(setup->access) !=
 385                     is_access_interleaved(runtime->access)) {
 386                         snd_ctl_notify(card, SNDRV_CTL_EVENT_MASK_VALUE,
 387                                                         &setup->access_id);
 388                         setup->access = runtime->access;
 389                 }
 390         }
 391         return 0;
 392 }
 393
 394 static void loopback_active_notify(struct loopback_pcm *dpcm)
 395 {
 396         snd_ctl_notify(dpcm->loopback->card,
 397                        SNDRV_CTL_EVENT_MASK_VALUE,
 398                        &get_setup(dpcm)->active_id);
 399 }
 400
 401 static int loopback_trigger(struct snd_pcm_substream *substream, int cmd)
 402 {
 403         struct snd_pcm_runtime *runtime = substream->runtime;
 404         struct loopback_pcm *dpcm = runtime->private_data;
 405         struct loopback_cable *cable = dpcm->cable;
 406         int err = 0, stream = 1 << substream->stream;
 407
 408         switch (cmd) {
 409         case SNDRV_PCM_TRIGGER_START:
 410                 err = loopback_check_format(cable, substream->stream);
 411                 if (err < 0)
 412                         return err;
 413                 dpcm->last_jiffies = jiffies;
 414                 dpcm->pcm_rate_shift = 0;
 415                 dpcm->last_drift = 0;
 416                 spin_lock(&cable->lock);
 417                 cable->running |= stream;
 418                 cable->pause &= ~stream;
 419                 err = cable->ops->start(dpcm);
 420                 spin_unlock(&cable->lock);
 421                 if (substream->stream == SNDRV_PCM_STREAM_PLAYBACK)
 422                         loopback_active_notify(dpcm);
 423                 break;
 424         case SNDRV_PCM_TRIGGER_STOP:
 425                 spin_lock(&cable->lock);
 426                 cable->running &= ~stream;
 427                 cable->pause &= ~stream;
 428                 err = cable->ops->stop(dpcm);
 429                 spin_unlock(&cable->lock);
 430                 if (substream->stream == SNDRV_PCM_STREAM_PLAYBACK)
 431                         loopback_active_notify(dpcm);
 432                 break;
 433         case SNDRV_PCM_TRIGGER_PAUSE_PUSH:
 434         case SNDRV_PCM_TRIGGER_SUSPEND:
 435                 spin_lock(&cable->lock);
 436                 cable->pause |= stream;
 437                 err = cable->ops->stop(dpcm);
 438                 spin_unlock(&cable->lock);
 439                 if (substream->stream == SNDRV_PCM_STREAM_PLAYBACK)
 440                         loopback_active_notify(dpcm);
 441                 break;
 442         case SNDRV_PCM_TRIGGER_PAUSE_RELEASE:
 443         case SNDRV_PCM_TRIGGER_RESUME:
 444                 spin_lock(&cable->lock);
 445                 dpcm->last_jiffies = jiffies;
 446                 cable->pause &= ~stream;
 447                 err = cable->ops->start(dpcm);
 448                 spin_unlock(&cable->lock);
 449                 if (substream->stream == SNDRV_PCM_STREAM_PLAYBACK)
 450                         loopback_active_notify(dpcm);
 451                 break;
 452         default:
 453                 return -EINVAL;
 454         }
 455         return err;
 456 }
 457
 458 static void params_change(struct snd_pcm_substream *substream)
 459 {
 460         struct snd_pcm_runtime *runtime = substream->runtime;
 461         struct loopback_pcm *dpcm = runtime->private_data;
 462         struct loopback_cable *cable = dpcm->cable;
 463
 464         cable->hw.formats = pcm_format_to_bits(runtime->format);
 465         cable->hw.rate_min = runtime->rate;
 466         cable->hw.rate_max = runtime->rate;
 467         cable->hw.channels_min = runtime->channels;
 468         cable->hw.channels_max = runtime->channels;
 469
 470         if (cable->snd_timer.instance) {
 471                 cable->hw.period_bytes_min =
 472                                 frames_to_bytes(runtime, runtime->period_size);
 473                 cable->hw.period_bytes_max = cable->hw.period_bytes_min;
 474         }
 475
 476 }
 477
 478 static int loopback_prepare(struct snd_pcm_substream *substream)
 479 {
 480         struct snd_pcm_runtime *runtime = substream->runtime;
 481         struct loopback_pcm *dpcm = runtime->private_data;
 482         struct loopback_cable *cable = dpcm->cable;
 483         int err, bps, salign;
 484
 485         if (cable->ops->stop_sync) {
 486                 err = cable->ops->stop_sync(dpcm);
 487                 if (err < 0)
 488                         return err;
 489         }
 490
 491         salign = (snd_pcm_format_physical_width(runtime->format) *
 492                                                 runtime->channels) / 8;
 493         bps = salign * runtime->rate;
 494         if (bps <= 0 || salign <= 0)
 495                 return -EINVAL;
 496
 497         dpcm->buf_pos = 0;
 498         dpcm->pcm_buffer_size = frames_to_bytes(runtime, runtime->buffer_size);
 499         dpcm->channel_buf_n = dpcm->pcm_buffer_size / runtime->channels;
 500         if (substream->stream == SNDRV_PCM_STREAM_CAPTURE) {
 501                 /* clear capture buffer */
 502                 dpcm->silent_size = dpcm->pcm_buffer_size;
 503                 snd_pcm_format_set_silence(runtime->format, runtime->dma_area,
 504                                            runtime->buffer_size * runtime->channels);
 505         }
 506
 507         dpcm->irq_pos = 0;
 508         dpcm->period_update_pending = 0;
 509         dpcm->pcm_bps = bps;
 510         dpcm->pcm_salign = salign;
 511         dpcm->pcm_period_size = frames_to_bytes(runtime, runtime->period_size);
 512
 513         mutex_lock(&dpcm->loopback->cable_lock);
 514         if (!(cable->valid & ~(1 << substream->stream)) ||
 515             (get_setup(dpcm)->notify &&
 516              substream->stream == SNDRV_PCM_STREAM_PLAYBACK))
 517                 params_change(substream);
 518         cable->valid |= 1 << substream->stream;
 519         mutex_unlock(&dpcm->loopback->cable_lock);
 520
 521         return 0;
 522 }
 523
 524 static void clear_capture_buf(struct loopback_pcm *dpcm, unsigned int bytes)
 525 {
 526         struct snd_pcm_runtime *runtime = dpcm->substream->runtime;
 527         char *dst = runtime->dma_area;
 528         unsigned int dst_off = dpcm->buf_pos;
 529
 530         if (dpcm->silent_size >= dpcm->pcm_buffer_size)
 531                 return;
 532         if (dpcm->silent_size + bytes > dpcm->pcm_buffer_size)
 533                 bytes = dpcm->pcm_buffer_size - dpcm->silent_size;
 534
 535         for (;;) {
 536                 unsigned int size = bytes;
 537                 if (dst_off + size > dpcm->pcm_buffer_size)
 538                         size = dpcm->pcm_buffer_size - dst_off;
 539                 snd_pcm_format_set_silence(runtime->format, dst + dst_off,
 540                                            bytes_to_frames(runtime, size) *
 541                                                 runtime->channels);
 542                 dpcm->silent_size += size;
 543                 bytes -= size;
 544                 if (!bytes)
 545                         break;
 546                 dst_off = 0;
 547         }
 548 }
 549
 550 static void copy_play_buf_part_n(struct loopback_pcm *play, struct loopback_pcm *capt,
 551                                  unsigned int size, unsigned int src_off, unsigned int dst_off)
 552 {
 553         unsigned int channels = capt->substream->runtime->channels;
 554         unsigned int size_p_ch = size / channels;
 555         unsigned int src_off_ch = src_off / channels;
 556         unsigned int dst_off_ch = dst_off / channels;
 557         int i;
 558
 559         for (i = 0; i < channels; i++) {
 560                 memcpy(capt->substream->runtime->dma_area + capt->channel_buf_n * i + dst_off_ch,
 561                        play->substream->runtime->dma_area + play->channel_buf_n * i + src_off_ch,
 562                        size_p_ch);
 563         }
 564 }
 565
 566 static void copy_play_buf(struct loopback_pcm *play,
 567                           struct loopback_pcm *capt,
 568                           unsigned int bytes)
 569 {
 570         struct snd_pcm_runtime *runtime = play->substream->runtime;
 571         char *src = runtime->dma_area;
 572         char *dst = capt->substream->runtime->dma_area;
 573         unsigned int src_off = play->buf_pos;
 574         unsigned int dst_off = capt->buf_pos;
 575         unsigned int clear_bytes = 0;
 576
 577         /* check if playback is draining, trim the capture copy size
 578          * when our pointer is at the end of playback ring buffer */
 579         if (runtime->state == SNDRV_PCM_STATE_DRAINING &&
 580             snd_pcm_playback_hw_avail(runtime) < runtime->buffer_size) {
 581                 snd_pcm_uframes_t appl_ptr, appl_ptr1, diff;
 582                 appl_ptr = appl_ptr1 = runtime->control->appl_ptr;
 583                 appl_ptr1 -= appl_ptr1 % runtime->buffer_size;
 584                 appl_ptr1 += play->buf_pos / play->pcm_salign;
 585                 if (appl_ptr < appl_ptr1)
 586                         appl_ptr1 -= runtime->buffer_size;
 587                 diff = (appl_ptr - appl_ptr1) * play->pcm_salign;
 588                 if (diff < bytes) {
 589                         clear_bytes = bytes - diff;
 590                         bytes = diff;
 591                 }
 592         }
 593
 594         for (;;) {
 595                 unsigned int size = bytes;
 596                 if (src_off + size > play->pcm_buffer_size)
 597                         size = play->pcm_buffer_size - src_off;
 598                 if (dst_off + size > capt->pcm_buffer_size)
 599                         size = capt->pcm_buffer_size - dst_off;
 600                 if (!is_access_interleaved(runtime->access))
 601                         copy_play_buf_part_n(play, capt, size, src_off, dst_off);
 602                 else
 603                         memcpy(dst + dst_off, src + src_off, size);
 604                 capt->silent_size = 0;
 605                 bytes -= size;
 606                 if (!bytes)
 607                         break;
 608                 src_off = (src_off + size) % play->pcm_buffer_size;
 609                 dst_off = (dst_off + size) % capt->pcm_buffer_size;
 610         }
 611
 612         if (clear_bytes > 0) {
 613                 clear_capture_buf(capt, clear_bytes);
 614                 capt->silent_size = 0;
 615         }
 616 }
 617
 618 static inline unsigned int bytepos_delta(struct loopback_pcm *dpcm,
 619                                          unsigned int jiffies_delta)
 620 {
 621         unsigned long last_pos;
 622         unsigned int delta;
 623
 624         last_pos = byte_pos(dpcm, dpcm->irq_pos);
 625         dpcm->irq_pos += jiffies_delta * dpcm->pcm_bps;
 626         delta = byte_pos(dpcm, dpcm->irq_pos) - last_pos;
 627         if (delta >= dpcm->last_drift)
 628                 delta -= dpcm->last_drift;
 629         dpcm->last_drift = 0;
 630         if (dpcm->irq_pos >= dpcm->period_size_frac) {
 631                 dpcm->irq_pos %= dpcm->period_size_frac;
 632                 dpcm->period_update_pending = 1;
 633         }
 634         return delta;
 635 }
 636
 637 static inline void bytepos_finish(struct loopback_pcm *dpcm,
 638                                   unsigned int delta)
 639 {
 640         dpcm->buf_pos += delta;
 641         dpcm->buf_pos %= dpcm->pcm_buffer_size;
 642 }
 643
 644 /* call in cable->lock */
 645 static unsigned int loopback_jiffies_timer_pos_update
 646                 (struct loopback_cable *cable)
 647 {
 648         struct loopback_pcm *dpcm_play =
 649                         cable->streams[SNDRV_PCM_STREAM_PLAYBACK];
 650         struct loopback_pcm *dpcm_capt =
 651                         cable->streams[SNDRV_PCM_STREAM_CAPTURE];
 652         unsigned long delta_play = 0, delta_capt = 0, cur_jiffies;
 653         unsigned int running, count1, count2;
 654
 655         cur_jiffies = jiffies;
 656         running = cable->running ^ cable->pause;
 657         if (running & (1 << SNDRV_PCM_STREAM_PLAYBACK)) {
 658                 delta_play = cur_jiffies - dpcm_play->last_jiffies;
 659                 dpcm_play->last_jiffies += delta_play;
 660         }
 661
 662         if (running & (1 << SNDRV_PCM_STREAM_CAPTURE)) {
 663                 delta_capt = cur_jiffies - dpcm_capt->last_jiffies;
 664                 dpcm_capt->last_jiffies += delta_capt;
 665         }
 666
 667         if (delta_play == 0 && delta_capt == 0)
 668                 goto unlock;
 669
 670         if (delta_play > delta_capt) {
 671                 count1 = bytepos_delta(dpcm_play, delta_play - delta_capt);
 672                 bytepos_finish(dpcm_play, count1);
 673                 delta_play = delta_capt;
 674         } else if (delta_play < delta_capt) {
 675                 count1 = bytepos_delta(dpcm_capt, delta_capt - delta_play);
 676                 clear_capture_buf(dpcm_capt, count1);
 677                 bytepos_finish(dpcm_capt, count1);
 678                 delta_capt = delta_play;
 679         }
 680
 681         if (delta_play == 0 && delta_capt == 0)
 682                 goto unlock;
 683
 684         /* note delta_capt == delta_play at this moment */
 685         count1 = bytepos_delta(dpcm_play, delta_play);
 686         count2 = bytepos_delta(dpcm_capt, delta_capt);
 687         if (count1 < count2) {
 688                 dpcm_capt->last_drift = count2 - count1;
 689                 count1 = count2;
 690         } else if (count1 > count2) {
 691                 dpcm_play->last_drift = count1 - count2;
 692         }
 693         copy_play_buf(dpcm_play, dpcm_capt, count1);
 694         bytepos_finish(dpcm_play, count1);
 695         bytepos_finish(dpcm_capt, count1);
 696  unlock:
 697         return running;
 698 }
 699
 700 static void loopback_jiffies_timer_function(struct timer_list *t)
 701 {
 702         struct loopback_pcm *dpcm = from_timer(dpcm, t, timer);
 703         unsigned long flags;
 704
 705         spin_lock_irqsave(&dpcm->cable->lock, flags);
 706         if (loopback_jiffies_timer_pos_update(dpcm->cable) &
 707                         (1 << dpcm->substream->stream)) {
 708                 loopback_jiffies_timer_start(dpcm);
 709                 if (dpcm->period_update_pending) {
 710                         dpcm->period_update_pending = 0;
 711                         spin_unlock_irqrestore(&dpcm->cable->lock, flags);
 712                         /* need to unlock before calling below */
 713                         snd_pcm_period_elapsed(dpcm->substream);
 714                         return;
 715                 }
 716         }
 717         spin_unlock_irqrestore(&dpcm->cable->lock, flags);
 718 }
 719
 720 /* call in cable->lock */
 721 static int loopback_snd_timer_check_resolution(struct snd_pcm_runtime *runtime,
 722                                                unsigned long resolution)
 723 {
 724         if (resolution != runtime->timer_resolution) {
 725                 struct loopback_pcm *dpcm = runtime->private_data;
 726                 struct loopback_cable *cable = dpcm->cable;
 727                 /* Worst case estimation of possible values for resolution
 728                  * resolution <= (512 * 1024) frames / 8kHz in nsec
 729                  * resolution <= 65.536.000.000 nsec
 730                  *
 731                  * period_size <= 65.536.000.000 nsec / 1000nsec/usec * 192kHz +
 732                  *  500.000
 733                  * period_size <= 12.582.912.000.000  <64bit
 734                  *  / 1.000.000 usec/sec
 735                  */
 736                 snd_pcm_uframes_t period_size_usec =
 737                                 resolution / 1000 * runtime->rate;
 738                 /* round to nearest sample rate */
 739                 snd_pcm_uframes_t period_size =
 740                                 (period_size_usec + 500 * 1000) / (1000 * 1000);
 741
 742                 pcm_err(dpcm->substream->pcm,
 743                         "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.",
 744                         runtime->period_size, resolution, period_size,
 745                         cable->snd_timer.id.card,
 746                         cable->snd_timer.id.device,
 747                         cable->snd_timer.id.subdevice,
 748                         period_size);
 749                 return -EINVAL;
 750         }
 751         return 0;
 752 }
 753
 754 static void loopback_snd_timer_period_elapsed(struct loopback_cable *cable,
 755                                               int event,
 756                                               unsigned long resolution)
 757 {
 758         struct loopback_pcm *dpcm_play, *dpcm_capt;
 759         struct snd_pcm_substream *substream_play, *substream_capt;
 760         struct snd_pcm_runtime *valid_runtime;
 761         unsigned int running, elapsed_bytes;
 762         unsigned long flags;
 763
 764         spin_lock_irqsave(&cable->lock, flags);
 765         running = cable->running ^ cable->pause;
 766         /* no need to do anything if no stream is running */
 767         if (!running) {
 768                 spin_unlock_irqrestore(&cable->lock, flags);
 769                 return;
 770         }
 771
 772         dpcm_play = cable->streams[SNDRV_PCM_STREAM_PLAYBACK];
 773         dpcm_capt = cable->streams[SNDRV_PCM_STREAM_CAPTURE];
 774
 775         if (event == SNDRV_TIMER_EVENT_MSTOP) {
 776                 if (!dpcm_play ||
 777                     dpcm_play->substream->runtime->state !=
 778                                 SNDRV_PCM_STATE_DRAINING) {
 779                         spin_unlock_irqrestore(&cable->lock, flags);
 780                         return;
 781                 }
 782         }
 783
 784         substream_play = (running & (1 << SNDRV_PCM_STREAM_PLAYBACK)) ?
 785                         dpcm_play->substream : NULL;
 786         substream_capt = (running & (1 << SNDRV_PCM_STREAM_CAPTURE)) ?
 787                         dpcm_capt->substream : NULL;
 788         valid_runtime = (running & (1 << SNDRV_PCM_STREAM_PLAYBACK)) ?
 789                                 dpcm_play->substream->runtime :
 790                                 dpcm_capt->substream->runtime;
 791
 792         /* resolution is only valid for SNDRV_TIMER_EVENT_TICK events */
 793         if (event == SNDRV_TIMER_EVENT_TICK) {
 794                 /* The hardware rules guarantee that playback and capture period
 795                  * are the same. Therefore only one device has to be checked
 796                  * here.
 797                  */
 798                 if (loopback_snd_timer_check_resolution(valid_runtime,
 799                                                         resolution) < 0) {
 800                         spin_unlock_irqrestore(&cable->lock, flags);
 801                         if (substream_play)
 802                                 snd_pcm_stop_xrun(substream_play);
 803                         if (substream_capt)
 804                                 snd_pcm_stop_xrun(substream_capt);
 805                         return;
 806                 }
 807         }
 808
 809         elapsed_bytes = frames_to_bytes(valid_runtime,
 810                                         valid_runtime->period_size);
 811         /* The same timer interrupt is used for playback and capture device */
 812         if ((running & (1 << SNDRV_PCM_STREAM_PLAYBACK)) &&
 813             (running & (1 << SNDRV_PCM_STREAM_CAPTURE))) {
 814                 copy_play_buf(dpcm_play, dpcm_capt, elapsed_bytes);
 815                 bytepos_finish(dpcm_play, elapsed_bytes);
 816                 bytepos_finish(dpcm_capt, elapsed_bytes);
 817         } else if (running & (1 << SNDRV_PCM_STREAM_PLAYBACK)) {
 818                 bytepos_finish(dpcm_play, elapsed_bytes);
 819         } else if (running & (1 << SNDRV_PCM_STREAM_CAPTURE)) {
 820                 clear_capture_buf(dpcm_capt, elapsed_bytes);
 821                 bytepos_finish(dpcm_capt, elapsed_bytes);
 822         }
 823         spin_unlock_irqrestore(&cable->lock, flags);
 824
 825         if (substream_play)
 826                 snd_pcm_period_elapsed(substream_play);
 827         if (substream_capt)
 828                 snd_pcm_period_elapsed(substream_capt);
 829 }
 830
 831 static void loopback_snd_timer_function(struct snd_timer_instance *timeri,
 832                                         unsigned long resolution,
 833                                         unsigned long ticks)
 834 {
 835         struct loopback_cable *cable = timeri->callback_data;
 836
 837         loopback_snd_timer_period_elapsed(cable, SNDRV_TIMER_EVENT_TICK,
 838                                           resolution);
 839 }
 840
 841 static void loopback_snd_timer_work(struct work_struct *work)
 842 {
 843         struct loopback_cable *cable;
 844
 845         cable = container_of(work, struct loopback_cable, snd_timer.event_work);
 846         loopback_snd_timer_period_elapsed(cable, SNDRV_TIMER_EVENT_MSTOP, 0);
 847 }
 848
 849 static void loopback_snd_timer_event(struct snd_timer_instance *timeri,
 850                                      int event,
 851                                      struct timespec64 *tstamp,
 852                                      unsigned long resolution)
 853 {
 854         /* Do not lock cable->lock here because timer->lock is already hold.
 855          * There are other functions which first lock cable->lock and than
 856          * timer->lock e.g.
 857          * loopback_trigger()
 858          * spin_lock(&cable->lock)
 859          * loopback_snd_timer_start()
 860          * snd_timer_start()
 861          * spin_lock(&timer->lock)
 862          * Therefore when using the oposit order of locks here it could result
 863          * in a deadlock.
 864          */
 865
 866         if (event == SNDRV_TIMER_EVENT_MSTOP) {
 867                 struct loopback_cable *cable = timeri->callback_data;
 868
 869                 /* sound card of the timer was stopped. Therefore there will not
 870                  * be any further timer callbacks. Due to this forward audio
 871                  * data from here if in draining state. When still in running
 872                  * state the streaming will be aborted by the usual timeout. It
 873                  * should not be aborted here because may be the timer sound
 874                  * card does only a recovery and the timer is back soon.
 875                  * This work triggers loopback_snd_timer_work()
 876                  */
 877                 schedule_work(&cable->snd_timer.event_work);
 878         }
 879 }
 880
 881 static void loopback_jiffies_timer_dpcm_info(struct loopback_pcm *dpcm,
 882                                              struct snd_info_buffer *buffer)
 883 {
 884         snd_iprintf(buffer, "    update_pending:\t%u\n",
 885                     dpcm->period_update_pending);
 886         snd_iprintf(buffer, "    irq_pos:\t\t%u\n", dpcm->irq_pos);
 887         snd_iprintf(buffer, "    period_frac:\t%u\n", dpcm->period_size_frac);
 888         snd_iprintf(buffer, "    last_jiffies:\t%lu (%lu)\n",
 889                     dpcm->last_jiffies, jiffies);
 890         snd_iprintf(buffer, "    timer_expires:\t%lu\n", dpcm->timer.expires);
 891 }
 892
 893 static void loopback_snd_timer_dpcm_info(struct loopback_pcm *dpcm,
 894                                          struct snd_info_buffer *buffer)
 895 {
 896         struct loopback_cable *cable = dpcm->cable;
 897
 898         snd_iprintf(buffer, "    sound timer:\thw:%d,%d,%d\n",
 899                     cable->snd_timer.id.card,
 900                     cable->snd_timer.id.device,
 901                     cable->snd_timer.id.subdevice);
 902         snd_iprintf(buffer, "    timer open:\t\t%s\n",
 903                     (cable->snd_timer.stream == SNDRV_PCM_STREAM_CAPTURE) ?
 904                             "capture" : "playback");
 905 }
 906
 907 static snd_pcm_uframes_t loopback_pointer(struct snd_pcm_substream *substream)
 908 {
 909         struct snd_pcm_runtime *runtime = substream->runtime;
 910         struct loopback_pcm *dpcm = runtime->private_data;
 911         snd_pcm_uframes_t pos;
 912
 913         spin_lock(&dpcm->cable->lock);
 914         if (dpcm->cable->ops->pos_update)
 915                 dpcm->cable->ops->pos_update(dpcm->cable);
 916         pos = dpcm->buf_pos;
 917         spin_unlock(&dpcm->cable->lock);
 918         return bytes_to_frames(runtime, pos);
 919 }
 920
 921 static const struct snd_pcm_hardware loopback_pcm_hardware =
 922 {
 923         .info =         (SNDRV_PCM_INFO_INTERLEAVED | SNDRV_PCM_INFO_MMAP |
 924                          SNDRV_PCM_INFO_MMAP_VALID | SNDRV_PCM_INFO_PAUSE |
 925                          SNDRV_PCM_INFO_RESUME | SNDRV_PCM_INFO_NONINTERLEAVED),
 926         .formats =      (SNDRV_PCM_FMTBIT_S16_LE | SNDRV_PCM_FMTBIT_S16_BE |
 927                          SNDRV_PCM_FMTBIT_S24_LE | SNDRV_PCM_FMTBIT_S24_BE |
 928                          SNDRV_PCM_FMTBIT_S24_3LE | SNDRV_PCM_FMTBIT_S24_3BE |
 929                          SNDRV_PCM_FMTBIT_S32_LE | SNDRV_PCM_FMTBIT_S32_BE |
 930                          SNDRV_PCM_FMTBIT_FLOAT_LE | SNDRV_PCM_FMTBIT_FLOAT_BE),
 931         .rates =        SNDRV_PCM_RATE_CONTINUOUS | SNDRV_PCM_RATE_8000_192000,
 932         .rate_min =             8000,
 933         .rate_max =             192000,
 934         .channels_min =         1,
 935         .channels_max =         32,
 936         .buffer_bytes_max =     2 * 1024 * 1024,
 937         .period_bytes_min =     64,
 938         /* note check overflow in frac_pos() using pcm_rate_shift before
 939            changing period_bytes_max value */
 940         .period_bytes_max =     1024 * 1024,
 941         .periods_min =          1,
 942         .periods_max =          1024,
 943         .fifo_size =            0,
 944 };
 945
 946 static void loopback_runtime_free(struct snd_pcm_runtime *runtime)
 947 {
 948         struct loopback_pcm *dpcm = runtime->private_data;
 949         kfree(dpcm);
 950 }
 951
 952 static int loopback_hw_free(struct snd_pcm_substream *substream)
 953 {
 954         struct snd_pcm_runtime *runtime = substream->runtime;
 955         struct loopback_pcm *dpcm = runtime->private_data;
 956         struct loopback_cable *cable = dpcm->cable;
 957
 958         mutex_lock(&dpcm->loopback->cable_lock);
 959         cable->valid &= ~(1 << substream->stream);
 960         mutex_unlock(&dpcm->loopback->cable_lock);
 961         return 0;
 962 }
 963
 964 static unsigned int get_cable_index(struct snd_pcm_substream *substream)
 965 {
 966         if (!substream->pcm->device)
 967                 return substream->stream;
 968         else
 969                 return !substream->stream;
 970 }
 971
 972 static int rule_format(struct snd_pcm_hw_params *params,
 973                        struct snd_pcm_hw_rule *rule)
 974 {
 975         struct loopback_pcm *dpcm = rule->private;
 976         struct loopback_cable *cable = dpcm->cable;
 977         struct snd_mask m;
 978
 979         snd_mask_none(&m);
 980         mutex_lock(&dpcm->loopback->cable_lock);
 981         m.bits[0] = (u_int32_t)cable->hw.formats;
 982         m.bits[1] = (u_int32_t)(cable->hw.formats >> 32);
 983         mutex_unlock(&dpcm->loopback->cable_lock);
 984         return snd_mask_refine(hw_param_mask(params, rule->var), &m);
 985 }
 986
 987 static int rule_rate(struct snd_pcm_hw_params *params,
 988                      struct snd_pcm_hw_rule *rule)
 989 {
 990         struct loopback_pcm *dpcm = rule->private;
 991         struct loopback_cable *cable = dpcm->cable;
 992         struct snd_interval t;
 993
 994         mutex_lock(&dpcm->loopback->cable_lock);
 995         t.min = cable->hw.rate_min;
 996         t.max = cable->hw.rate_max;
 997         mutex_unlock(&dpcm->loopback->cable_lock);
 998         t.openmin = t.openmax = 0;
 999         t.integer = 0;
1000         return snd_interval_refine(hw_param_interval(params, rule->var), &t);
1001 }
1002
1003 static int rule_channels(struct snd_pcm_hw_params *params,
1004                          struct snd_pcm_hw_rule *rule)
1005 {
1006         struct loopback_pcm *dpcm = rule->private;
1007         struct loopback_cable *cable = dpcm->cable;
1008         struct snd_interval t;
1009
1010         mutex_lock(&dpcm->loopback->cable_lock);
1011         t.min = cable->hw.channels_min;
1012         t.max = cable->hw.channels_max;
1013         mutex_unlock(&dpcm->loopback->cable_lock);
1014         t.openmin = t.openmax = 0;
1015         t.integer = 0;
1016         return snd_interval_refine(hw_param_interval(params, rule->var), &t);
1017 }
1018
1019 static int rule_period_bytes(struct snd_pcm_hw_params *params,
1020                              struct snd_pcm_hw_rule *rule)
1021 {
1022         struct loopback_pcm *dpcm = rule->private;
1023         struct loopback_cable *cable = dpcm->cable;
1024         struct snd_interval t;
1025
1026         mutex_lock(&dpcm->loopback->cable_lock);
1027         t.min = cable->hw.period_bytes_min;
1028         t.max = cable->hw.period_bytes_max;
1029         mutex_unlock(&dpcm->loopback->cable_lock);
1030         t.openmin = 0;
1031         t.openmax = 0;
1032         t.integer = 0;
1033         return snd_interval_refine(hw_param_interval(params, rule->var), &t);
1034 }
1035
1036 static void free_cable(struct snd_pcm_substream *substream)
1037 {
1038         struct loopback *loopback = substream->private_data;
1039         int dev = get_cable_index(substream);
1040         struct loopback_cable *cable;
1041
1042         cable = loopback->cables[substream->number][dev];
1043         if (!cable)
1044                 return;
1045         if (cable->streams[!substream->stream]) {
1046                 /* other stream is still alive */
1047                 spin_lock_irq(&cable->lock);
1048                 cable->streams[substream->stream] = NULL;
1049                 spin_unlock_irq(&cable->lock);
1050         } else {
1051                 struct loopback_pcm *dpcm = substream->runtime->private_data;
1052
1053                 if (cable->ops && cable->ops->close_cable && dpcm)
1054                         cable->ops->close_cable(dpcm);
1055                 /* free the cable */
1056                 loopback->cables[substream->number][dev] = NULL;
1057                 kfree(cable);
1058         }
1059 }
1060
1061 static int loopback_jiffies_timer_open(struct loopback_pcm *dpcm)
1062 {
1063         timer_setup(&dpcm->timer, loopback_jiffies_timer_function, 0);
1064
1065         return 0;
1066 }
1067
1068 static const struct loopback_ops loopback_jiffies_timer_ops = {
1069         .open = loopback_jiffies_timer_open,
1070         .start = loopback_jiffies_timer_start,
1071         .stop = loopback_jiffies_timer_stop,
1072         .stop_sync = loopback_jiffies_timer_stop_sync,
1073         .close_substream = loopback_jiffies_timer_stop_sync,
1074         .pos_update = loopback_jiffies_timer_pos_update,
1075         .dpcm_info = loopback_jiffies_timer_dpcm_info,
1076 };
1077
1078 static int loopback_parse_timer_id(const char *str,
1079                                    struct snd_timer_id *tid)
1080 {
1081         /* [<pref>:](<card name>|<card idx>)[{.,}<dev idx>[{.,}<subdev idx>]] */
1082         const char * const sep_dev = ".,";
1083         const char * const sep_pref = ":";
1084         const char *name = str;
1085         char *sep, save = '\0';
1086         int card_idx = 0, dev = 0, subdev = 0;
1087         int err;
1088
1089         sep = strpbrk(str, sep_pref);
1090         if (sep)
1091                 name = sep + 1;
1092         sep = strpbrk(name, sep_dev);
1093         if (sep) {
1094                 save = *sep;
1095                 *sep = '\0';
1096         }
1097         err = kstrtoint(name, 0, &card_idx);
1098         if (err == -EINVAL) {
1099                 /* Must be the name, not number */
1100                 for (card_idx = 0; card_idx < snd_ecards_limit; card_idx++) {
1101                         struct snd_card *card = snd_card_ref(card_idx);
1102
1103                         if (card) {
1104                                 if (!strcmp(card->id, name))
1105                                         err = 0;
1106                                 snd_card_unref(card);
1107                         }
1108                         if (!err)
1109                                 break;
1110                 }
1111         }
1112         if (sep) {
1113                 *sep = save;
1114                 if (!err) {
1115                         char *sep2, save2 = '\0';
1116
1117                         sep2 = strpbrk(sep + 1, sep_dev);
1118                         if (sep2) {
1119                                 save2 = *sep2;
1120                                 *sep2 = '\0';
1121                         }
1122                         err = kstrtoint(sep + 1, 0, &dev);
1123                         if (sep2) {
1124                                 *sep2 = save2;
1125                                 if (!err)
1126                                         err = kstrtoint(sep2 + 1, 0, &subdev);
1127                         }
1128                 }
1129         }
1130         if (!err && tid) {
1131                 tid->card = card_idx;
1132                 tid->device = dev;
1133                 tid->subdevice = subdev;
1134         }
1135         return err;
1136 }
1137
1138 /* call in loopback->cable_lock */
1139 static int loopback_snd_timer_open(struct loopback_pcm *dpcm)
1140 {
1141         int err = 0;
1142         struct snd_timer_id tid = {
1143                 .dev_class = SNDRV_TIMER_CLASS_PCM,
1144                 .dev_sclass = SNDRV_TIMER_SCLASS_APPLICATION,
1145         };
1146         struct snd_timer_instance *timeri;
1147         struct loopback_cable *cable = dpcm->cable;
1148
1149         /* check if timer was already opened. It is only opened once
1150          * per playback and capture subdevice (aka cable).
1151          */
1152         if (cable->snd_timer.instance)
1153                 goto exit;
1154
1155         err = loopback_parse_timer_id(dpcm->loopback->timer_source, &tid);
1156         if (err < 0) {
1157                 pcm_err(dpcm->substream->pcm,
1158                         "Parsing timer source \'%s\' failed with %d",
1159                         dpcm->loopback->timer_source, err);
1160                 goto exit;
1161         }
1162
1163         cable->snd_timer.stream = dpcm->substream->stream;
1164         cable->snd_timer.id = tid;
1165
1166         timeri = snd_timer_instance_new(dpcm->loopback->card->id);
1167         if (!timeri) {
1168                 err = -ENOMEM;
1169                 goto exit;
1170         }
1171         /* The callback has to be called from another work. If
1172          * SNDRV_TIMER_IFLG_FAST is specified it will be called from the
1173          * snd_pcm_period_elapsed() call of the selected sound card.
1174          * snd_pcm_period_elapsed() helds snd_pcm_stream_lock_irqsave().
1175          * Due to our callback loopback_snd_timer_function() also calls
1176          * snd_pcm_period_elapsed() which calls snd_pcm_stream_lock_irqsave().
1177          * This would end up in a dead lock.
1178          */
1179         timeri->flags |= SNDRV_TIMER_IFLG_AUTO;
1180         timeri->callback = loopback_snd_timer_function;
1181         timeri->callback_data = (void *)cable;
1182         timeri->ccallback = loopback_snd_timer_event;
1183
1184         /* initialise a work used for draining */
1185         INIT_WORK(&cable->snd_timer.event_work, loopback_snd_timer_work);
1186
1187         /* The mutex loopback->cable_lock is kept locked.
1188          * Therefore snd_timer_open() cannot be called a second time
1189          * by the other device of the same cable.
1190          * Therefore the following issue cannot happen:
1191          * [proc1] Call loopback_timer_open() ->
1192          *         Unlock cable->lock for snd_timer_close/open() call
1193          * [proc2] Call loopback_timer_open() -> snd_timer_open(),
1194          *         snd_timer_start()
1195          * [proc1] Call snd_timer_open() and overwrite running timer
1196          *         instance
1197          */
1198         err = snd_timer_open(timeri, &cable->snd_timer.id, current->pid);
1199         if (err < 0) {
1200                 pcm_err(dpcm->substream->pcm,
1201                         "snd_timer_open (%d,%d,%d) failed with %d",
1202                         cable->snd_timer.id.card,
1203                         cable->snd_timer.id.device,
1204                         cable->snd_timer.id.subdevice,
1205                         err);
1206                 snd_timer_instance_free(timeri);
1207                 goto exit;
1208         }
1209
1210         cable->snd_timer.instance = timeri;
1211
1212 exit:
1213         return err;
1214 }
1215
1216 /* stop_sync() is not required for sound timer because it does not need to be
1217  * restarted in loopback_prepare() on Xrun recovery
1218  */
1219 static const struct loopback_ops loopback_snd_timer_ops = {
1220         .open = loopback_snd_timer_open,
1221         .start = loopback_snd_timer_start,
1222         .stop = loopback_snd_timer_stop,
1223         .close_cable = loopback_snd_timer_close_cable,
1224         .dpcm_info = loopback_snd_timer_dpcm_info,
1225 };
1226
1227 static int loopback_open(struct snd_pcm_substream *substream)
1228 {
1229         struct snd_pcm_runtime *runtime = substream->runtime;
1230         struct loopback *loopback = substream->private_data;
1231         struct loopback_pcm *dpcm;
1232         struct loopback_cable *cable = NULL;
1233         int err = 0;
1234         int dev = get_cable_index(substream);
1235
1236         mutex_lock(&loopback->cable_lock);
1237         dpcm = kzalloc(sizeof(*dpcm), GFP_KERNEL);
1238         if (!dpcm) {
1239                 err = -ENOMEM;
1240                 goto unlock;
1241         }
1242         dpcm->loopback = loopback;
1243         dpcm->substream = substream;
1244
1245         cable = loopback->cables[substream->number][dev];
1246         if (!cable) {
1247                 cable = kzalloc(sizeof(*cable), GFP_KERNEL);
1248                 if (!cable) {
1249                         err = -ENOMEM;
1250                         goto unlock;
1251                 }
1252                 spin_lock_init(&cable->lock);
1253                 cable->hw = loopback_pcm_hardware;
1254                 if (loopback->timer_source)
1255                         cable->ops = &loopback_snd_timer_ops;
1256                 else
1257                         cable->ops = &loopback_jiffies_timer_ops;
1258                 loopback->cables[substream->number][dev] = cable;
1259         }
1260         dpcm->cable = cable;
1261         runtime->private_data = dpcm;
1262
1263         if (cable->ops->open) {
1264                 err = cable->ops->open(dpcm);
1265                 if (err < 0)
1266                         goto unlock;
1267         }
1268
1269         snd_pcm_hw_constraint_integer(runtime, SNDRV_PCM_HW_PARAM_PERIODS);
1270
1271         /* use dynamic rules based on actual runtime->hw values */
1272         /* note that the default rules created in the PCM midlevel code */
1273         /* are cached -> they do not reflect the actual state */
1274         err = snd_pcm_hw_rule_add(runtime, 0,
1275                                   SNDRV_PCM_HW_PARAM_FORMAT,
1276                                   rule_format, dpcm,
1277                                   SNDRV_PCM_HW_PARAM_FORMAT, -1);
1278         if (err < 0)
1279                 goto unlock;
1280         err = snd_pcm_hw_rule_add(runtime, 0,
1281                                   SNDRV_PCM_HW_PARAM_RATE,
1282                                   rule_rate, dpcm,
1283                                   SNDRV_PCM_HW_PARAM_RATE, -1);
1284         if (err < 0)
1285                 goto unlock;
1286         err = snd_pcm_hw_rule_add(runtime, 0,
1287                                   SNDRV_PCM_HW_PARAM_CHANNELS,
1288                                   rule_channels, dpcm,
1289                                   SNDRV_PCM_HW_PARAM_CHANNELS, -1);
1290         if (err < 0)
1291                 goto unlock;
1292
1293         /* In case of sound timer the period time of both devices of the same
1294          * loop has to be the same.
1295          * This rule only takes effect if a sound timer was chosen
1296          */
1297         if (cable->snd_timer.instance) {
1298                 err = snd_pcm_hw_rule_add(runtime, 0,
1299                                           SNDRV_PCM_HW_PARAM_PERIOD_BYTES,
1300                                           rule_period_bytes, dpcm,
1301                                           SNDRV_PCM_HW_PARAM_PERIOD_BYTES, -1);
1302                 if (err < 0)
1303                         goto unlock;
1304         }
1305
1306         /* loopback_runtime_free() has not to be called if kfree(dpcm) was
1307          * already called here. Otherwise it will end up with a double free.
1308          */
1309         runtime->private_free = loopback_runtime_free;
1310         if (get_notify(dpcm))
1311                 runtime->hw = loopback_pcm_hardware;
1312         else
1313                 runtime->hw = cable->hw;
1314
1315         spin_lock_irq(&cable->lock);
1316         cable->streams[substream->stream] = dpcm;
1317         spin_unlock_irq(&cable->lock);
1318
1319  unlock:
1320         if (err < 0) {
1321                 free_cable(substream);
1322                 kfree(dpcm);
1323         }
1324         mutex_unlock(&loopback->cable_lock);
1325         return err;
1326 }
1327
1328 static int loopback_close(struct snd_pcm_substream *substream)
1329 {
1330         struct loopback *loopback = substream->private_data;
1331         struct loopback_pcm *dpcm = substream->runtime->private_data;
1332         int err = 0;
1333
1334         if (dpcm->cable->ops->close_substream)
1335                 err = dpcm->cable->ops->close_substream(dpcm);
1336         mutex_lock(&loopback->cable_lock);
1337         free_cable(substream);
1338         mutex_unlock(&loopback->cable_lock);
1339         return err;
1340 }
1341
1342 static const struct snd_pcm_ops loopback_pcm_ops = {
1343         .open =         loopback_open,
1344         .close =        loopback_close,
1345         .hw_free =      loopback_hw_free,
1346         .prepare =      loopback_prepare,
1347         .trigger =      loopback_trigger,
1348         .pointer =      loopback_pointer,
1349 };
1350
1351 static int loopback_pcm_new(struct loopback *loopback,
1352                             int device, int substreams)
1353 {
1354         struct snd_pcm *pcm;
1355         int err;
1356
1357         err = snd_pcm_new(loopback->card, "Loopback PCM", device,
1358                           substreams, substreams, &pcm);
1359         if (err < 0)
1360                 return err;
1361         snd_pcm_set_ops(pcm, SNDRV_PCM_STREAM_PLAYBACK, &loopback_pcm_ops);
1362         snd_pcm_set_ops(pcm, SNDRV_PCM_STREAM_CAPTURE, &loopback_pcm_ops);
1363         snd_pcm_set_managed_buffer_all(pcm, SNDRV_DMA_TYPE_VMALLOC, NULL, 0, 0);
1364
1365         pcm->private_data = loopback;
1366         pcm->info_flags = 0;
1367         strcpy(pcm->name, "Loopback PCM");
1368
1369         loopback->pcm[device] = pcm;
1370         return 0;
1371 }
1372
1373 static int loopback_rate_shift_info(struct snd_kcontrol *kcontrol,
1374                                     struct snd_ctl_elem_info *uinfo)
1375 {
1376         uinfo->type = SNDRV_CTL_ELEM_TYPE_INTEGER;
1377         uinfo->count = 1;
1378         uinfo->value.integer.min = 80000;
1379         uinfo->value.integer.max = 120000;
1380         uinfo->value.integer.step = 1;
1381         return 0;
1382 }
1383
1384 static int loopback_rate_shift_get(struct snd_kcontrol *kcontrol,
1385                                    struct snd_ctl_elem_value *ucontrol)
1386 {
1387         struct loopback *loopback = snd_kcontrol_chip(kcontrol);
1388
1389         mutex_lock(&loopback->cable_lock);
1390         ucontrol->value.integer.value[0] =
1391                 loopback->setup[kcontrol->id.subdevice]
1392                                [kcontrol->id.device].rate_shift;
1393         mutex_unlock(&loopback->cable_lock);
1394         return 0;
1395 }
1396
1397 static int loopback_rate_shift_put(struct snd_kcontrol *kcontrol,
1398                                    struct snd_ctl_elem_value *ucontrol)
1399 {
1400         struct loopback *loopback = snd_kcontrol_chip(kcontrol);
1401         unsigned int val;
1402         int change = 0;
1403
1404         val = ucontrol->value.integer.value[0];
1405         if (val < 80000)
1406                 val = 80000;
1407         if (val > 120000)
1408                 val = 120000;
1409         mutex_lock(&loopback->cable_lock);
1410         if (val != loopback->setup[kcontrol->id.subdevice]
1411                                   [kcontrol->id.device].rate_shift) {
1412                 loopback->setup[kcontrol->id.subdevice]
1413                                [kcontrol->id.device].rate_shift = val;
1414                 change = 1;
1415         }
1416         mutex_unlock(&loopback->cable_lock);
1417         return change;
1418 }
1419
1420 static int loopback_notify_get(struct snd_kcontrol *kcontrol,
1421                                struct snd_ctl_elem_value *ucontrol)
1422 {
1423         struct loopback *loopback = snd_kcontrol_chip(kcontrol);
1424
1425         mutex_lock(&loopback->cable_lock);
1426         ucontrol->value.integer.value[0] =
1427                 loopback->setup[kcontrol->id.subdevice]
1428                                [kcontrol->id.device].notify;
1429         mutex_unlock(&loopback->cable_lock);
1430         return 0;
1431 }
1432
1433 static int loopback_notify_put(struct snd_kcontrol *kcontrol,
1434                                struct snd_ctl_elem_value *ucontrol)
1435 {
1436         struct loopback *loopback = snd_kcontrol_chip(kcontrol);
1437         unsigned int val;
1438         int change = 0;
1439
1440         val = ucontrol->value.integer.value[0] ? 1 : 0;
1441         mutex_lock(&loopback->cable_lock);
1442         if (val != loopback->setup[kcontrol->id.subdevice]
1443                                 [kcontrol->id.device].notify) {
1444                 loopback->setup[kcontrol->id.subdevice]
1445                         [kcontrol->id.device].notify = val;
1446                 change = 1;
1447         }
1448         mutex_unlock(&loopback->cable_lock);
1449         return change;
1450 }
1451
1452 static int loopback_active_get(struct snd_kcontrol *kcontrol,
1453                                struct snd_ctl_elem_value *ucontrol)
1454 {
1455         struct loopback *loopback = snd_kcontrol_chip(kcontrol);
1456         struct loopback_cable *cable;
1457
1458         unsigned int val = 0;
1459
1460         mutex_lock(&loopback->cable_lock);
1461         cable = loopback->cables[kcontrol->id.subdevice][kcontrol->id.device ^ 1];
1462         if (cable != NULL) {
1463                 unsigned int running = cable->running ^ cable->pause;
1464
1465                 val = (running & (1 << SNDRV_PCM_STREAM_PLAYBACK)) ? 1 : 0;
1466         }
1467         mutex_unlock(&loopback->cable_lock);
1468         ucontrol->value.integer.value[0] = val;
1469         return 0;
1470 }
1471
1472 static int loopback_format_info(struct snd_kcontrol *kcontrol,
1473                                 struct snd_ctl_elem_info *uinfo)
1474 {
1475         uinfo->type = SNDRV_CTL_ELEM_TYPE_INTEGER;
1476         uinfo->count = 1;
1477         uinfo->value.integer.min = 0;
1478         uinfo->value.integer.max = (__force int)SNDRV_PCM_FORMAT_LAST;
1479         uinfo->value.integer.step = 1;
1480         return 0;
1481 }
1482
1483 static int loopback_format_get(struct snd_kcontrol *kcontrol,
1484                                struct snd_ctl_elem_value *ucontrol)
1485 {
1486         struct loopback *loopback = snd_kcontrol_chip(kcontrol);
1487
1488         ucontrol->value.integer.value[0] =
1489                 (__force int)loopback->setup[kcontrol->id.subdevice]
1490                                [kcontrol->id.device].format;
1491         return 0;
1492 }
1493
1494 static int loopback_rate_info(struct snd_kcontrol *kcontrol,
1495                               struct snd_ctl_elem_info *uinfo)
1496 {
1497         uinfo->type = SNDRV_CTL_ELEM_TYPE_INTEGER;
1498         uinfo->count = 1;
1499         uinfo->value.integer.min = 0;
1500         uinfo->value.integer.max = 192000;
1501         uinfo->value.integer.step = 1;
1502         return 0;
1503 }
1504
1505 static int loopback_rate_get(struct snd_kcontrol *kcontrol,
1506                              struct snd_ctl_elem_value *ucontrol)
1507 {
1508         struct loopback *loopback = snd_kcontrol_chip(kcontrol);
1509
1510         mutex_lock(&loopback->cable_lock);
1511         ucontrol->value.integer.value[0] =
1512                 loopback->setup[kcontrol->id.subdevice]
1513                                [kcontrol->id.device].rate;
1514         mutex_unlock(&loopback->cable_lock);
1515         return 0;
1516 }
1517
1518 static int loopback_channels_info(struct snd_kcontrol *kcontrol,
1519                                   struct snd_ctl_elem_info *uinfo)
1520 {
1521         uinfo->type = SNDRV_CTL_ELEM_TYPE_INTEGER;
1522         uinfo->count = 1;
1523         uinfo->value.integer.min = 1;
1524         uinfo->value.integer.max = 1024;
1525         uinfo->value.integer.step = 1;
1526         return 0;
1527 }
1528
1529 static int loopback_channels_get(struct snd_kcontrol *kcontrol,
1530                                  struct snd_ctl_elem_value *ucontrol)
1531 {
1532         struct loopback *loopback = snd_kcontrol_chip(kcontrol);
1533
1534         mutex_lock(&loopback->cable_lock);
1535         ucontrol->value.integer.value[0] =
1536                 loopback->setup[kcontrol->id.subdevice]
1537                                [kcontrol->id.device].channels;
1538         mutex_unlock(&loopback->cable_lock);
1539         return 0;
1540 }
1541
1542 static int loopback_access_info(struct snd_kcontrol *kcontrol,
1543                                 struct snd_ctl_elem_info *uinfo)
1544 {
1545         const char * const texts[] = {"Interleaved", "Non-interleaved"};
1546
1547         return snd_ctl_enum_info(uinfo, 1, ARRAY_SIZE(texts), texts);
1548 }
1549
1550 static int loopback_access_get(struct snd_kcontrol *kcontrol,
1551                                struct snd_ctl_elem_value *ucontrol)
1552 {
1553         struct loopback *loopback = snd_kcontrol_chip(kcontrol);
1554         snd_pcm_access_t access;
1555
1556         mutex_lock(&loopback->cable_lock);
1557         access = loopback->setup[kcontrol->id.subdevice][kcontrol->id.device].access;
1558
1559         ucontrol->value.enumerated.item[0] = !is_access_interleaved(access);
1560
1561         mutex_unlock(&loopback->cable_lock);
1562         return 0;
1563 }
1564
1565 static const struct snd_kcontrol_new loopback_controls[]  = {
1566 {
1567         .iface =        SNDRV_CTL_ELEM_IFACE_PCM,
1568         .name =         "PCM Rate Shift 100000",
1569         .info =         loopback_rate_shift_info,
1570         .get =          loopback_rate_shift_get,
1571         .put =          loopback_rate_shift_put,
1572 },
1573 {
1574         .iface =        SNDRV_CTL_ELEM_IFACE_PCM,
1575         .name =         "PCM Notify",
1576         .info =         snd_ctl_boolean_mono_info,
1577         .get =          loopback_notify_get,
1578         .put =          loopback_notify_put,
1579 },
1580 #define ACTIVE_IDX 2
1581 {
1582         .access =       SNDRV_CTL_ELEM_ACCESS_READ,
1583         .iface =        SNDRV_CTL_ELEM_IFACE_PCM,
1584         .name =         "PCM Slave Active",
1585         .info =         snd_ctl_boolean_mono_info,
1586         .get =          loopback_active_get,
1587 },
1588 #define FORMAT_IDX 3
1589 {
1590         .access =       SNDRV_CTL_ELEM_ACCESS_READ,
1591         .iface =        SNDRV_CTL_ELEM_IFACE_PCM,
1592         .name =         "PCM Slave Format",
1593         .info =         loopback_format_info,
1594         .get =          loopback_format_get
1595 },
1596 #define RATE_IDX 4
1597 {
1598         .access =       SNDRV_CTL_ELEM_ACCESS_READ,
1599         .iface =        SNDRV_CTL_ELEM_IFACE_PCM,
1600         .name =         "PCM Slave Rate",
1601         .info =         loopback_rate_info,
1602         .get =          loopback_rate_get
1603 },
1604 #define CHANNELS_IDX 5
1605 {
1606         .access =       SNDRV_CTL_ELEM_ACCESS_READ,
1607         .iface =        SNDRV_CTL_ELEM_IFACE_PCM,
1608         .name =         "PCM Slave Channels",
1609         .info =         loopback_channels_info,
1610         .get =          loopback_channels_get
1611 },
1612 #define ACCESS_IDX 6
1613 {
1614         .access =       SNDRV_CTL_ELEM_ACCESS_READ,
1615         .iface =        SNDRV_CTL_ELEM_IFACE_PCM,
1616         .name =         "PCM Slave Access Mode",
1617         .info =         loopback_access_info,
1618         .get =          loopback_access_get,
1619 },
1620 };
1621
1622 static int loopback_mixer_new(struct loopback *loopback, int notify)
1623 {
1624         struct snd_card *card = loopback->card;
1625         struct snd_pcm *pcm;
1626         struct snd_kcontrol *kctl;
1627         struct loopback_setup *setup;
1628         int err, dev, substr, substr_count, idx;
1629
1630         strcpy(card->mixername, "Loopback Mixer");
1631         for (dev = 0; dev < 2; dev++) {
1632                 pcm = loopback->pcm[dev];
1633                 substr_count =
1634                     pcm->streams[SNDRV_PCM_STREAM_CAPTURE].substream_count;
1635                 for (substr = 0; substr < substr_count; substr++) {
1636                         setup = &loopback->setup[substr][dev];
1637                         setup->notify = notify;
1638                         setup->rate_shift = NO_PITCH;
1639                         setup->format = SNDRV_PCM_FORMAT_S16_LE;
1640                         setup->access = SNDRV_PCM_ACCESS_RW_INTERLEAVED;
1641                         setup->rate = 48000;
1642                         setup->channels = 2;
1643                         for (idx = 0; idx < ARRAY_SIZE(loopback_controls);
1644                                                                         idx++) {
1645                                 kctl = snd_ctl_new1(&loopback_controls[idx],
1646                                                     loopback);
1647                                 if (!kctl)
1648                                         return -ENOMEM;
1649                                 kctl->id.device = dev;
1650                                 kctl->id.subdevice = substr;
1651
1652                                 /* Add the control before copying the id so that
1653                                  * the numid field of the id is set in the copy.
1654                                  */
1655                                 err = snd_ctl_add(card, kctl);
1656                                 if (err < 0)
1657                                         return err;
1658
1659                                 switch (idx) {
1660                                 case ACTIVE_IDX:
1661                                         setup->active_id = kctl->id;
1662                                         break;
1663                                 case FORMAT_IDX:
1664                                         setup->format_id = kctl->id;
1665                                         break;
1666                                 case RATE_IDX:
1667                                         setup->rate_id = kctl->id;
1668                                         break;
1669                                 case CHANNELS_IDX:
1670                                         setup->channels_id = kctl->id;
1671                                         break;
1672                                 case ACCESS_IDX:
1673                                         setup->access_id = kctl->id;
1674                                         break;
1675                                 default:
1676                                         break;
1677                                 }
1678                         }
1679                 }
1680         }
1681         return 0;
1682 }
1683
1684 static void print_dpcm_info(struct snd_info_buffer *buffer,
1685                             struct loopback_pcm *dpcm,
1686                             const char *id)
1687 {
1688         snd_iprintf(buffer, "  %s\n", id);
1689         if (dpcm == NULL) {
1690                 snd_iprintf(buffer, "    inactive\n");
1691                 return;
1692         }
1693         snd_iprintf(buffer, "    buffer_size:\t%u\n", dpcm->pcm_buffer_size);
1694         snd_iprintf(buffer, "    buffer_pos:\t\t%u\n", dpcm->buf_pos);
1695         snd_iprintf(buffer, "    silent_size:\t%u\n", dpcm->silent_size);
1696         snd_iprintf(buffer, "    period_size:\t%u\n", dpcm->pcm_period_size);
1697         snd_iprintf(buffer, "    bytes_per_sec:\t%u\n", dpcm->pcm_bps);
1698         snd_iprintf(buffer, "    sample_align:\t%u\n", dpcm->pcm_salign);
1699         snd_iprintf(buffer, "    rate_shift:\t\t%u\n", dpcm->pcm_rate_shift);
1700         if (dpcm->cable->ops->dpcm_info)
1701                 dpcm->cable->ops->dpcm_info(dpcm, buffer);
1702 }
1703
1704 static void print_substream_info(struct snd_info_buffer *buffer,
1705                                  struct loopback *loopback,
1706                                  int sub,
1707                                  int num)
1708 {
1709         struct loopback_cable *cable = loopback->cables[sub][num];
1710
1711         snd_iprintf(buffer, "Cable %i substream %i:\n", num, sub);
1712         if (cable == NULL) {
1713                 snd_iprintf(buffer, "  inactive\n");
1714                 return;
1715         }
1716         snd_iprintf(buffer, "  valid: %u\n", cable->valid);
1717         snd_iprintf(buffer, "  running: %u\n", cable->running);
1718         snd_iprintf(buffer, "  pause: %u\n", cable->pause);
1719         print_dpcm_info(buffer, cable->streams[0], "Playback");
1720         print_dpcm_info(buffer, cable->streams[1], "Capture");
1721 }
1722
1723 static void print_cable_info(struct snd_info_entry *entry,
1724                              struct snd_info_buffer *buffer)
1725 {
1726         struct loopback *loopback = entry->private_data;
1727         int sub, num;
1728
1729         mutex_lock(&loopback->cable_lock);
1730         num = entry->name[strlen(entry->name)-1];
1731         num = num == '0' ? 0 : 1;
1732         for (sub = 0; sub < MAX_PCM_SUBSTREAMS; sub++)
1733                 print_substream_info(buffer, loopback, sub, num);
1734         mutex_unlock(&loopback->cable_lock);
1735 }
1736
1737 static int loopback_cable_proc_new(struct loopback *loopback, int cidx)
1738 {
1739         char name[32];
1740
1741         snprintf(name, sizeof(name), "cable#%d", cidx);
1742         return snd_card_ro_proc_new(loopback->card, name, loopback,
1743                                     print_cable_info);
1744 }
1745
1746 static void loopback_set_timer_source(struct loopback *loopback,
1747                                       const char *value)
1748 {
1749         if (loopback->timer_source) {
1750                 devm_kfree(loopback->card->dev, loopback->timer_source);
1751                 loopback->timer_source = NULL;
1752         }
1753         if (value && *value)
1754                 loopback->timer_source = devm_kstrdup(loopback->card->dev,
1755                                                       value, GFP_KERNEL);
1756 }
1757
1758 static void print_timer_source_info(struct snd_info_entry *entry,
1759                                     struct snd_info_buffer *buffer)
1760 {
1761         struct loopback *loopback = entry->private_data;
1762
1763         mutex_lock(&loopback->cable_lock);
1764         snd_iprintf(buffer, "%s\n",
1765                     loopback->timer_source ? loopback->timer_source : "");
1766         mutex_unlock(&loopback->cable_lock);
1767 }
1768
1769 static void change_timer_source_info(struct snd_info_entry *entry,
1770                                      struct snd_info_buffer *buffer)
1771 {
1772         struct loopback *loopback = entry->private_data;
1773         char line[64];
1774
1775         mutex_lock(&loopback->cable_lock);
1776         if (!snd_info_get_line(buffer, line, sizeof(line)))
1777                 loopback_set_timer_source(loopback, strim(line));
1778         mutex_unlock(&loopback->cable_lock);
1779 }
1780
1781 static int loopback_timer_source_proc_new(struct loopback *loopback)
1782 {
1783         return snd_card_rw_proc_new(loopback->card, "timer_source", loopback,
1784                                     print_timer_source_info,
1785                                     change_timer_source_info);
1786 }
1787
1788 static int loopback_probe(struct platform_device *devptr)
1789 {
1790         struct snd_card *card;
1791         struct loopback *loopback;
1792         int dev = devptr->id;
1793         int err;
1794
1795         err = snd_devm_card_new(&devptr->dev, index[dev], id[dev], THIS_MODULE,
1796                                 sizeof(struct loopback), &card);
1797         if (err < 0)
1798                 return err;
1799         loopback = card->private_data;
1800
1801         if (pcm_substreams[dev] < 1)
1802                 pcm_substreams[dev] = 1;
1803         if (pcm_substreams[dev] > MAX_PCM_SUBSTREAMS)
1804                 pcm_substreams[dev] = MAX_PCM_SUBSTREAMS;
1805
1806         loopback->card = card;
1807         loopback_set_timer_source(loopback, timer_source[dev]);
1808
1809         mutex_init(&loopback->cable_lock);
1810
1811         err = loopback_pcm_new(loopback, 0, pcm_substreams[dev]);
1812         if (err < 0)
1813                 return err;
1814         err = loopback_pcm_new(loopback, 1, pcm_substreams[dev]);
1815         if (err < 0)
1816                 return err;
1817         err = loopback_mixer_new(loopback, pcm_notify[dev] ? 1 : 0);
1818         if (err < 0)
1819                 return err;
1820         loopback_cable_proc_new(loopback, 0);
1821         loopback_cable_proc_new(loopback, 1);
1822         loopback_timer_source_proc_new(loopback);
1823         strcpy(card->driver, "Loopback");
1824         strcpy(card->shortname, "Loopback");
1825         sprintf(card->longname, "Loopback %i", dev + 1);
1826         err = snd_card_register(card);
1827         if (err < 0)
1828                 return err;
1829         platform_set_drvdata(devptr, card);
1830         return 0;
1831 }
1832
1833 static int loopback_suspend(struct device *pdev)
1834 {
1835         struct snd_card *card = dev_get_drvdata(pdev);
1836
1837         snd_power_change_state(card, SNDRV_CTL_POWER_D3hot);
1838         return 0;
1839 }
1840
1841 static int loopback_resume(struct device *pdev)
1842 {
1843         struct snd_card *card = dev_get_drvdata(pdev);
1844
1845         snd_power_change_state(card, SNDRV_CTL_POWER_D0);
1846         return 0;
1847 }
1848
1849 static DEFINE_SIMPLE_DEV_PM_OPS(loopback_pm, loopback_suspend, loopback_resume);
1850
1851 #define SND_LOOPBACK_DRIVER     "snd_aloop"
1852
1853 static struct platform_driver loopback_driver = {
1854         .probe          = loopback_probe,
1855         .driver         = {
1856                 .name   = SND_LOOPBACK_DRIVER,
1857                 .pm     = &loopback_pm,
1858         },
1859 };
1860
1861 static void loopback_unregister_all(void)
1862 {
1863         int i;
1864
1865         for (i = 0; i < ARRAY_SIZE(devices); ++i)
1866                 platform_device_unregister(devices[i]);
1867         platform_driver_unregister(&loopback_driver);
1868 }
1869
1870 static int __init alsa_card_loopback_init(void)
1871 {
1872         int i, err, cards;
1873
1874         err = platform_driver_register(&loopback_driver);
1875         if (err < 0)
1876                 return err;
1877
1878
1879         cards = 0;
1880         for (i = 0; i < SNDRV_CARDS; i++) {
1881                 struct platform_device *device;
1882                 if (!enable[i])
1883                         continue;
1884                 device = platform_device_register_simple(SND_LOOPBACK_DRIVER,
1885                                                          i, NULL, 0);
1886                 if (IS_ERR(device))
1887                         continue;
1888                 if (!platform_get_drvdata(device)) {
1889                         platform_device_unregister(device);
1890                         continue;
1891                 }
1892                 devices[i] = device;
1893                 cards++;
1894         }
1895         if (!cards) {
1896 #ifdef MODULE
1897                 printk(KERN_ERR "aloop: No loopback enabled\n");
1898 #endif
1899                 loopback_unregister_all();
1900                 return -ENODEV;
1901         }
1902         return 0;
1903 }
1904
1905 static void __exit alsa_card_loopback_exit(void)
1906 {
1907         loopback_unregister_all();
1908 }
1909
1910 module_init(alsa_card_loopback_init)
1911 module_exit(alsa_card_loopback_exit)