drivers/most/most_snd.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 /*
   3  * sound.c - Sound component for Mostcore
   4  *
   5  * Copyright (C) 2015 Microchip Technology Germany II GmbH & Co. KG
   6  */
   7
   8 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
   9
  10 #include <linux/module.h>
  11 #include <linux/printk.h>
  12 #include <linux/kernel.h>
  13 #include <linux/slab.h>
  14 #include <linux/init.h>
  15 #include <sound/core.h>
  16 #include <sound/pcm.h>
  17 #include <sound/pcm_params.h>
  18 #include <linux/sched.h>
  19 #include <linux/kthread.h>
  20 #include <linux/most.h>
  21
  22 #define DRIVER_NAME "sound"
  23 #define STRING_SIZE     80
  24
  25 static struct most_component comp;
  26
  27 /**
  28  * struct channel - private structure to keep channel specific data
  29  * @substream: stores the substream structure
  30  * @iface: interface for which the channel belongs to
  31  * @cfg: channel configuration
  32  * @card: registered sound card
  33  * @list: list for private use
  34  * @id: channel index
  35  * @period_pos: current period position (ring buffer)
  36  * @buffer_pos: current buffer position (ring buffer)
  37  * @is_stream_running: identifies whether a stream is running or not
  38  * @opened: set when the stream is opened
  39  * @playback_task: playback thread
  40  * @playback_waitq: waitq used by playback thread
  41  */
  42 struct channel {
  43         struct snd_pcm_substream *substream;
  44         struct snd_pcm_hardware pcm_hardware;
  45         struct most_interface *iface;
  46         struct most_channel_config *cfg;
  47         struct snd_card *card;
  48         struct list_head list;
  49         int id;
  50         unsigned int period_pos;
  51         unsigned int buffer_pos;
  52         bool is_stream_running;
  53         struct task_struct *playback_task;
  54         wait_queue_head_t playback_waitq;
  55         void (*copy_fn)(void *alsa, void *most, unsigned int bytes);
  56 };
  57
  58 struct sound_adapter {
  59         struct list_head dev_list;
  60         struct most_interface *iface;
  61         struct snd_card *card;
  62         struct list_head list;
  63         bool registered;
  64         int pcm_dev_idx;
  65 };
  66
  67 static struct list_head adpt_list;
  68
  69 #define MOST_PCM_INFO (SNDRV_PCM_INFO_MMAP | \
  70                        SNDRV_PCM_INFO_MMAP_VALID | \
  71                        SNDRV_PCM_INFO_BATCH | \
  72                        SNDRV_PCM_INFO_INTERLEAVED | \
  73                        SNDRV_PCM_INFO_BLOCK_TRANSFER)
  74
  75 static void swap_copy16(u16 *dest, const u16 *source, unsigned int bytes)
  76 {
  77         unsigned int i = 0;
  78
  79         while (i < (bytes / 2)) {
  80                 dest[i] = swab16(source[i]);
  81                 i++;
  82         }
  83 }
  84
  85 static void swap_copy24(u8 *dest, const u8 *source, unsigned int bytes)
  86 {
  87         unsigned int i = 0;
  88
  89         if (bytes < 2)
  90                 return;
  91         while (i < bytes - 2) {
  92                 dest[i] = source[i + 2];
  93                 dest[i + 1] = source[i + 1];
  94                 dest[i + 2] = source[i];
  95                 i += 3;
  96         }
  97 }
  98
  99 static void swap_copy32(u32 *dest, const u32 *source, unsigned int bytes)
 100 {
 101         unsigned int i = 0;
 102
 103         while (i < bytes / 4) {
 104                 dest[i] = swab32(source[i]);
 105                 i++;
 106         }
 107 }
 108
 109 static void alsa_to_most_memcpy(void *alsa, void *most, unsigned int bytes)
 110 {
 111         memcpy(most, alsa, bytes);
 112 }
 113
 114 static void alsa_to_most_copy16(void *alsa, void *most, unsigned int bytes)
 115 {
 116         swap_copy16(most, alsa, bytes);
 117 }
 118
 119 static void alsa_to_most_copy24(void *alsa, void *most, unsigned int bytes)
 120 {
 121         swap_copy24(most, alsa, bytes);
 122 }
 123
 124 static void alsa_to_most_copy32(void *alsa, void *most, unsigned int bytes)
 125 {
 126         swap_copy32(most, alsa, bytes);
 127 }
 128
 129 static void most_to_alsa_memcpy(void *alsa, void *most, unsigned int bytes)
 130 {
 131         memcpy(alsa, most, bytes);
 132 }
 133
 134 static void most_to_alsa_copy16(void *alsa, void *most, unsigned int bytes)
 135 {
 136         swap_copy16(alsa, most, bytes);
 137 }
 138
 139 static void most_to_alsa_copy24(void *alsa, void *most, unsigned int bytes)
 140 {
 141         swap_copy24(alsa, most, bytes);
 142 }
 143
 144 static void most_to_alsa_copy32(void *alsa, void *most, unsigned int bytes)
 145 {
 146         swap_copy32(alsa, most, bytes);
 147 }
 148
 149 /**
 150  * get_channel - get pointer to channel
 151  * @iface: interface structure
 152  * @channel_id: channel ID
 153  *
 154  * This traverses the channel list and returns the channel matching the
 155  * ID and interface.
 156  *
 157  * Returns pointer to channel on success or NULL otherwise.
 158  */
 159 static struct channel *get_channel(struct most_interface *iface,
 160                                    int channel_id)
 161 {
 162         struct sound_adapter *adpt = iface->priv;
 163         struct channel *channel;
 164
 165         list_for_each_entry(channel, &adpt->dev_list, list) {
 166                 if ((channel->iface == iface) && (channel->id == channel_id))
 167                         return channel;
 168         }
 169         return NULL;
 170 }
 171
 172 /**
 173  * copy_data - implements data copying function
 174  * @channel: channel
 175  * @mbo: MBO from core
 176  *
 177  * Copy data from/to ring buffer to/from MBO and update the buffer position
 178  */
 179 static bool copy_data(struct channel *channel, struct mbo *mbo)
 180 {
 181         struct snd_pcm_runtime *const runtime = channel->substream->runtime;
 182         unsigned int const frame_bytes = channel->cfg->subbuffer_size;
 183         unsigned int const buffer_size = runtime->buffer_size;
 184         unsigned int frames;
 185         unsigned int fr0;
 186
 187         if (channel->cfg->direction & MOST_CH_RX)
 188                 frames = mbo->processed_length / frame_bytes;
 189         else
 190                 frames = mbo->buffer_length / frame_bytes;
 191         fr0 = min(buffer_size - channel->buffer_pos, frames);
 192
 193         channel->copy_fn(runtime->dma_area + channel->buffer_pos * frame_bytes,
 194                          mbo->virt_address,
 195                          fr0 * frame_bytes);
 196
 197         if (frames > fr0) {
 198                 /* wrap around at end of ring buffer */
 199                 channel->copy_fn(runtime->dma_area,
 200                                  mbo->virt_address + fr0 * frame_bytes,
 201                                  (frames - fr0) * frame_bytes);
 202         }
 203
 204         channel->buffer_pos += frames;
 205         if (channel->buffer_pos >= buffer_size)
 206                 channel->buffer_pos -= buffer_size;
 207         channel->period_pos += frames;
 208         if (channel->period_pos >= runtime->period_size) {
 209                 channel->period_pos -= runtime->period_size;
 210                 return true;
 211         }
 212         return false;
 213 }
 214
 215 /**
 216  * playback_thread - function implements the playback thread
 217  * @data: private data
 218  *
 219  * Thread which does the playback functionality in a loop. It waits for a free
 220  * MBO from mostcore for a particular channel and copy the data from ring buffer
 221  * to MBO. Submit the MBO back to mostcore, after copying the data.
 222  *
 223  * Returns 0 on success or error code otherwise.
 224  */
 225 static int playback_thread(void *data)
 226 {
 227         struct channel *const channel = data;
 228
 229         while (!kthread_should_stop()) {
 230                 struct mbo *mbo = NULL;
 231                 bool period_elapsed = false;
 232
 233                 wait_event_interruptible(
 234                         channel->playback_waitq,
 235                         kthread_should_stop() ||
 236                         (channel->is_stream_running &&
 237                          (mbo = most_get_mbo(channel->iface, channel->id,
 238                                              &comp))));
 239                 if (!mbo)
 240                         continue;
 241
 242                 if (channel->is_stream_running)
 243                         period_elapsed = copy_data(channel, mbo);
 244                 else
 245                         memset(mbo->virt_address, 0, mbo->buffer_length);
 246
 247                 most_submit_mbo(mbo);
 248                 if (period_elapsed)
 249                         snd_pcm_period_elapsed(channel->substream);
 250         }
 251         return 0;
 252 }
 253
 254 /**
 255  * pcm_open - implements open callback function for PCM middle layer
 256  * @substream: pointer to ALSA PCM substream
 257  *
 258  * This is called when a PCM substream is opened. At least, the function should
 259  * initialize the runtime->hw record.
 260  *
 261  * Returns 0 on success or error code otherwise.
 262  */
 263 static int pcm_open(struct snd_pcm_substream *substream)
 264 {
 265         struct channel *channel = substream->private_data;
 266         struct snd_pcm_runtime *runtime = substream->runtime;
 267         struct most_channel_config *cfg = channel->cfg;
 268         int ret;
 269
 270         channel->substream = substream;
 271
 272         if (cfg->direction == MOST_CH_TX) {
 273                 channel->playback_task = kthread_run(playback_thread, channel,
 274                                                      "most_audio_playback");
 275                 if (IS_ERR(channel->playback_task)) {
 276                         pr_err("Couldn't start thread\n");
 277                         return PTR_ERR(channel->playback_task);
 278                 }
 279         }
 280
 281         ret = most_start_channel(channel->iface, channel->id, &comp);
 282         if (ret) {
 283                 pr_err("most_start_channel() failed!\n");
 284                 if (cfg->direction == MOST_CH_TX)
 285                         kthread_stop(channel->playback_task);
 286                 return ret;
 287         }
 288
 289         runtime->hw = channel->pcm_hardware;
 290         return 0;
 291 }
 292
 293 /**
 294  * pcm_close - implements close callback function for PCM middle layer
 295  * @substream: sub-stream pointer
 296  *
 297  * Obviously, this is called when a PCM substream is closed. Any private
 298  * instance for a PCM substream allocated in the open callback will be
 299  * released here.
 300  *
 301  * Returns 0 on success or error code otherwise.
 302  */
 303 static int pcm_close(struct snd_pcm_substream *substream)
 304 {
 305         struct channel *channel = substream->private_data;
 306
 307         if (channel->cfg->direction == MOST_CH_TX)
 308                 kthread_stop(channel->playback_task);
 309         most_stop_channel(channel->iface, channel->id, &comp);
 310         return 0;
 311 }
 312
 313 /**
 314  * pcm_prepare - implements prepare callback function for PCM middle layer
 315  * @substream: substream pointer
 316  *
 317  * This callback is called when the PCM is "prepared". Format rate, sample rate,
 318  * etc., can be set here. This callback can be called many times at each setup.
 319  *
 320  * Returns 0 on success or error code otherwise.
 321  */
 322 static int pcm_prepare(struct snd_pcm_substream *substream)
 323 {
 324         struct channel *channel = substream->private_data;
 325         struct snd_pcm_runtime *runtime = substream->runtime;
 326         struct most_channel_config *cfg = channel->cfg;
 327         int width = snd_pcm_format_physical_width(runtime->format);
 328
 329         channel->copy_fn = NULL;
 330
 331         if (cfg->direction == MOST_CH_TX) {
 332                 if (snd_pcm_format_big_endian(runtime->format) || width == 8)
 333                         channel->copy_fn = alsa_to_most_memcpy;
 334                 else if (width == 16)
 335                         channel->copy_fn = alsa_to_most_copy16;
 336                 else if (width == 24)
 337                         channel->copy_fn = alsa_to_most_copy24;
 338                 else if (width == 32)
 339                         channel->copy_fn = alsa_to_most_copy32;
 340         } else {
 341                 if (snd_pcm_format_big_endian(runtime->format) || width == 8)
 342                         channel->copy_fn = most_to_alsa_memcpy;
 343                 else if (width == 16)
 344                         channel->copy_fn = most_to_alsa_copy16;
 345                 else if (width == 24)
 346                         channel->copy_fn = most_to_alsa_copy24;
 347                 else if (width == 32)
 348                         channel->copy_fn = most_to_alsa_copy32;
 349         }
 350
 351         if (!channel->copy_fn)
 352                 return -EINVAL;
 353         channel->period_pos = 0;
 354         channel->buffer_pos = 0;
 355         return 0;
 356 }
 357
 358 /**
 359  * pcm_trigger - implements trigger callback function for PCM middle layer
 360  * @substream: substream pointer
 361  * @cmd: action to perform
 362  *
 363  * This is called when the PCM is started, stopped or paused. The action will be
 364  * specified in the second argument, SNDRV_PCM_TRIGGER_XXX
 365  *
 366  * Returns 0 on success or error code otherwise.
 367  */
 368 static int pcm_trigger(struct snd_pcm_substream *substream, int cmd)
 369 {
 370         struct channel *channel = substream->private_data;
 371
 372         switch (cmd) {
 373         case SNDRV_PCM_TRIGGER_START:
 374                 channel->is_stream_running = true;
 375                 wake_up_interruptible(&channel->playback_waitq);
 376                 return 0;
 377
 378         case SNDRV_PCM_TRIGGER_STOP:
 379                 channel->is_stream_running = false;
 380                 return 0;
 381
 382         default:
 383                 return -EINVAL;
 384         }
 385         return 0;
 386 }
 387
 388 /**
 389  * pcm_pointer - implements pointer callback function for PCM middle layer
 390  * @substream: substream pointer
 391  *
 392  * This callback is called when the PCM middle layer inquires the current
 393  * hardware position on the buffer. The position must be returned in frames,
 394  * ranging from 0 to buffer_size-1.
 395  */
 396 static snd_pcm_uframes_t pcm_pointer(struct snd_pcm_substream *substream)
 397 {
 398         struct channel *channel = substream->private_data;
 399
 400         return channel->buffer_pos;
 401 }
 402
 403 /**
 404  * Initialization of struct snd_pcm_ops
 405  */
 406 static const struct snd_pcm_ops pcm_ops = {
 407         .open       = pcm_open,
 408         .close      = pcm_close,
 409         .prepare    = pcm_prepare,
 410         .trigger    = pcm_trigger,
 411         .pointer    = pcm_pointer,
 412 };
 413
 414 static int split_arg_list(char *buf, u16 *ch_num, char **sample_res)
 415 {
 416         char *num;
 417         int ret;
 418
 419         num = strsep(&buf, "x");
 420         if (!num)
 421                 goto err;
 422         ret = kstrtou16(num, 0, ch_num);
 423         if (ret)
 424                 goto err;
 425         *sample_res = strsep(&buf, ".\n");
 426         if (!*sample_res)
 427                 goto err;
 428         return 0;
 429
 430 err:
 431         pr_err("Bad PCM format\n");
 432         return -EINVAL;
 433 }
 434
 435 static const struct sample_resolution_info {
 436         const char *sample_res;
 437         int bytes;
 438         u64 formats;
 439 } sinfo[] = {
 440         { "8", 1, SNDRV_PCM_FMTBIT_S8 },
 441         { "16", 2, SNDRV_PCM_FMTBIT_S16_LE | SNDRV_PCM_FMTBIT_S16_BE },
 442         { "24", 3, SNDRV_PCM_FMTBIT_S24_3LE | SNDRV_PCM_FMTBIT_S24_3BE },
 443         { "32", 4, SNDRV_PCM_FMTBIT_S32_LE | SNDRV_PCM_FMTBIT_S32_BE },
 444 };
 445
 446 static int audio_set_hw_params(struct snd_pcm_hardware *pcm_hw,
 447                                u16 ch_num, char *sample_res,
 448                                struct most_channel_config *cfg)
 449 {
 450         int i;
 451
 452         for (i = 0; i < ARRAY_SIZE(sinfo); i++) {
 453                 if (!strcmp(sample_res, sinfo[i].sample_res))
 454                         goto found;
 455         }
 456         pr_err("Unsupported PCM format\n");
 457         return -EINVAL;
 458
 459 found:
 460         if (!ch_num) {
 461                 pr_err("Bad number of channels\n");
 462                 return -EINVAL;
 463         }
 464
 465         if (cfg->subbuffer_size != ch_num * sinfo[i].bytes) {
 466                 pr_err("Audio resolution doesn't fit subbuffer size\n");
 467                 return -EINVAL;
 468         }
 469
 470         pcm_hw->info = MOST_PCM_INFO;
 471         pcm_hw->rates = SNDRV_PCM_RATE_48000;
 472         pcm_hw->rate_min = 48000;
 473         pcm_hw->rate_max = 48000;
 474         pcm_hw->buffer_bytes_max = cfg->num_buffers * cfg->buffer_size;
 475         pcm_hw->period_bytes_min = cfg->buffer_size;
 476         pcm_hw->period_bytes_max = cfg->buffer_size;
 477         pcm_hw->periods_min = 1;
 478         pcm_hw->periods_max = cfg->num_buffers;
 479         pcm_hw->channels_min = ch_num;
 480         pcm_hw->channels_max = ch_num;
 481         pcm_hw->formats = sinfo[i].formats;
 482         return 0;
 483 }
 484
 485 static void release_adapter(struct sound_adapter *adpt)
 486 {
 487         struct channel *channel, *tmp;
 488
 489         list_for_each_entry_safe(channel, tmp, &adpt->dev_list, list) {
 490                 list_del(&channel->list);
 491                 kfree(channel);
 492         }
 493         if (adpt->card)
 494                 snd_card_free(adpt->card);
 495         list_del(&adpt->list);
 496         kfree(adpt);
 497 }
 498
 499 /**
 500  * audio_probe_channel - probe function of the driver module
 501  * @iface: pointer to interface instance
 502  * @channel_id: channel index/ID
 503  * @cfg: pointer to actual channel configuration
 504  * @arg_list: string that provides the name of the device to be created in /dev
 505  *            plus the desired audio resolution
 506  *
 507  * Creates sound card, pcm device, sets pcm ops and registers sound card.
 508  *
 509  * Returns 0 on success or error code otherwise.
 510  */
 511 static int audio_probe_channel(struct most_interface *iface, int channel_id,
 512                                struct most_channel_config *cfg,
 513                                char *device_name, char *arg_list)
 514 {
 515         struct channel *channel;
 516         struct sound_adapter *adpt;
 517         struct snd_pcm *pcm;
 518         int playback_count = 0;
 519         int capture_count = 0;
 520         int ret;
 521         int direction;
 522         u16 ch_num;
 523         char *sample_res;
 524         char arg_list_cpy[STRING_SIZE];
 525
 526         if (cfg->data_type != MOST_CH_SYNC) {
 527                 pr_err("Incompatible channel type\n");
 528                 return -EINVAL;
 529         }
 530         strscpy(arg_list_cpy, arg_list, STRING_SIZE);
 531         ret = split_arg_list(arg_list_cpy, &ch_num, &sample_res);
 532         if (ret < 0)
 533                 return ret;
 534
 535         list_for_each_entry(adpt, &adpt_list, list) {
 536                 if (adpt->iface != iface)
 537                         continue;
 538                 if (adpt->registered)
 539                         return -ENOSPC;
 540                 adpt->pcm_dev_idx++;
 541                 goto skip_adpt_alloc;
 542         }
 543         adpt = kzalloc(sizeof(*adpt), GFP_KERNEL);
 544         if (!adpt)
 545                 return -ENOMEM;
 546
 547         adpt->iface = iface;
 548         INIT_LIST_HEAD(&adpt->dev_list);
 549         iface->priv = adpt;
 550         list_add_tail(&adpt->list, &adpt_list);
 551         ret = snd_card_new(iface->driver_dev, -1, "INIC", THIS_MODULE,
 552                            sizeof(*channel), &adpt->card);
 553         if (ret < 0)
 554                 goto err_free_adpt;
 555         snprintf(adpt->card->driver, sizeof(adpt->card->driver),
 556                  "%s", DRIVER_NAME);
 557         snprintf(adpt->card->shortname, sizeof(adpt->card->shortname),
 558                  "Microchip INIC");
 559         snprintf(adpt->card->longname, sizeof(adpt->card->longname),
 560                  "%s at %s", adpt->card->shortname, iface->description);
 561 skip_adpt_alloc:
 562         if (get_channel(iface, channel_id)) {
 563                 pr_err("channel (%s:%d) is already linked\n",
 564                        iface->description, channel_id);
 565                 return -EEXIST;
 566         }
 567
 568         if (cfg->direction == MOST_CH_TX) {
 569                 playback_count = 1;
 570                 direction = SNDRV_PCM_STREAM_PLAYBACK;
 571         } else {
 572                 capture_count = 1;
 573                 direction = SNDRV_PCM_STREAM_CAPTURE;
 574         }
 575         channel = kzalloc(sizeof(*channel), GFP_KERNEL);
 576         if (!channel) {
 577                 ret = -ENOMEM;
 578                 goto err_free_adpt;
 579         }
 580         channel->card = adpt->card;
 581         channel->cfg = cfg;
 582         channel->iface = iface;
 583         channel->id = channel_id;
 584         init_waitqueue_head(&channel->playback_waitq);
 585         list_add_tail(&channel->list, &adpt->dev_list);
 586
 587         ret = audio_set_hw_params(&channel->pcm_hardware, ch_num, sample_res,
 588                                   cfg);
 589         if (ret)
 590                 goto err_free_adpt;
 591
 592         ret = snd_pcm_new(adpt->card, device_name, adpt->pcm_dev_idx,
 593                           playback_count, capture_count, &pcm);
 594
 595         if (ret < 0)
 596                 goto err_free_adpt;
 597
 598         pcm->private_data = channel;
 599         strscpy(pcm->name, device_name, sizeof(pcm->name));
 600         snd_pcm_set_ops(pcm, direction, &pcm_ops);
 601         snd_pcm_set_managed_buffer_all(pcm, SNDRV_DMA_TYPE_VMALLOC, NULL, 0, 0);
 602         return 0;
 603
 604 err_free_adpt:
 605         release_adapter(adpt);
 606         return ret;
 607 }
 608
 609 static int audio_create_sound_card(void)
 610 {
 611         int ret;
 612         struct sound_adapter *adpt;
 613
 614         list_for_each_entry(adpt, &adpt_list, list) {
 615                 if (!adpt->registered)
 616                         goto adpt_alloc;
 617         }
 618         return -ENODEV;
 619 adpt_alloc:
 620         ret = snd_card_register(adpt->card);
 621         if (ret < 0) {
 622                 release_adapter(adpt);
 623                 return ret;
 624         }
 625         adpt->registered = true;
 626         return 0;
 627 }
 628
 629 /**
 630  * audio_disconnect_channel - function to disconnect a channel
 631  * @iface: pointer to interface instance
 632  * @channel_id: channel index
 633  *
 634  * This frees allocated memory and removes the sound card from ALSA
 635  *
 636  * Returns 0 on success or error code otherwise.
 637  */
 638 static int audio_disconnect_channel(struct most_interface *iface,
 639                                     int channel_id)
 640 {
 641         struct channel *channel;
 642         struct sound_adapter *adpt = iface->priv;
 643
 644         channel = get_channel(iface, channel_id);
 645         if (!channel)
 646                 return -EINVAL;
 647
 648         list_del(&channel->list);
 649
 650         kfree(channel);
 651         if (list_empty(&adpt->dev_list))
 652                 release_adapter(adpt);
 653         return 0;
 654 }
 655
 656 /**
 657  * audio_rx_completion - completion handler for rx channels
 658  * @mbo: pointer to buffer object that has completed
 659  *
 660  * This searches for the channel this MBO belongs to and copy the data from MBO
 661  * to ring buffer
 662  *
 663  * Returns 0 on success or error code otherwise.
 664  */
 665 static int audio_rx_completion(struct mbo *mbo)
 666 {
 667         struct channel *channel = get_channel(mbo->ifp, mbo->hdm_channel_id);
 668         bool period_elapsed = false;
 669
 670         if (!channel)
 671                 return -EINVAL;
 672         if (channel->is_stream_running)
 673                 period_elapsed = copy_data(channel, mbo);
 674         most_put_mbo(mbo);
 675         if (period_elapsed)
 676                 snd_pcm_period_elapsed(channel->substream);
 677         return 0;
 678 }
 679
 680 /**
 681  * audio_tx_completion - completion handler for tx channels
 682  * @iface: pointer to interface instance
 683  * @channel_id: channel index/ID
 684  *
 685  * This searches the channel that belongs to this combination of interface
 686  * pointer and channel ID and wakes a process sitting in the wait queue of
 687  * this channel.
 688  *
 689  * Returns 0 on success or error code otherwise.
 690  */
 691 static int audio_tx_completion(struct most_interface *iface, int channel_id)
 692 {
 693         struct channel *channel = get_channel(iface, channel_id);
 694
 695         if (!channel)
 696                 return -EINVAL;
 697
 698         wake_up_interruptible(&channel->playback_waitq);
 699         return 0;
 700 }
 701
 702 /**
 703  * Initialization of the struct most_component
 704  */
 705 static struct most_component comp = {
 706         .mod = THIS_MODULE,
 707         .name = DRIVER_NAME,
 708         .probe_channel = audio_probe_channel,
 709         .disconnect_channel = audio_disconnect_channel,
 710         .rx_completion = audio_rx_completion,
 711         .tx_completion = audio_tx_completion,
 712         .cfg_complete = audio_create_sound_card,
 713 };
 714
 715 static int __init audio_init(void)
 716 {
 717         int ret;
 718
 719         INIT_LIST_HEAD(&adpt_list);
 720
 721         ret = most_register_component(&comp);
 722         if (ret) {
 723                 pr_err("Failed to register %s\n", comp.name);
 724                 return ret;
 725         }
 726         ret = most_register_configfs_subsys(&comp);
 727         if (ret) {
 728                 pr_err("Failed to register %s configfs subsys\n", comp.name);
 729                 most_deregister_component(&comp);
 730         }
 731         return ret;
 732 }
 733
 734 static void __exit audio_exit(void)
 735 {
 736         most_deregister_configfs_subsys(&comp);
 737         most_deregister_component(&comp);
 738 }
 739
 740 module_init(audio_init);
 741 module_exit(audio_exit);
 742
 743 MODULE_LICENSE("GPL");
 744 MODULE_AUTHOR("Christian Gromm <christian.gromm@microchip.com>");
 745 MODULE_DESCRIPTION("Sound Component Module for Mostcore");