drivers/usb/gadget/function/u_audio.c

   1 /*
   2  * u_audio.c -- interface to USB gadget "ALSA sound card" utilities
   3  *
   4  * Copyright (C) 2016
   5  * Author: Ruslan Bilovol <ruslan.bilovol@gmail.com>
   6  *
   7  * Sound card implementation was cut-and-pasted with changes
   8  * from f_uac2.c and has:
   9  *    Copyright (C) 2011
  10  *    Yadwinder Singh (yadi.brar01@gmail.com)
  11  *    Jaswinder Singh (jaswinder.singh@linaro.org)
  12  *
  13  * This program is free software; you can redistribute it and/or modify
  14  * it under the terms of the GNU General Public License as published by
  15  * the Free Software Foundation; either version 2 of the License, or
  16  * (at your option) any later version.
  17  *
  18  * This program is distributed in the hope that it will be useful,
  19  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  20  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  21  * GNU General Public License for more details.
  22  */
  23
  24 #include <linux/module.h>
  25 #include <sound/core.h>
  26 #include <sound/pcm.h>
  27 #include <sound/pcm_params.h>
  28
  29 #include "u_audio.h"
  30
  31 #define BUFF_SIZE_MAX   (PAGE_SIZE * 16)
  32 #define PRD_SIZE_MAX    PAGE_SIZE
  33 #define MIN_PERIODS     4
  34
  35 struct uac_req {
  36         struct uac_rtd_params *pp; /* parent param */
  37         struct usb_request *req;
  38 };
  39
  40 /* Runtime data params for one stream */
  41 struct uac_rtd_params {
  42         struct snd_uac_chip *uac; /* parent chip */
  43         bool ep_enabled; /* if the ep is enabled */
  44         /* Size of the ring buffer */
  45         size_t dma_bytes;
  46         unsigned char *dma_area;
  47
  48         struct snd_pcm_substream *ss;
  49
  50         /* Ring buffer */
  51         ssize_t hw_ptr;
  52
  53         void *rbuf;
  54
  55         size_t period_size;
  56
  57         unsigned max_psize;     /* MaxPacketSize of endpoint */
  58         struct uac_req *ureq;
  59
  60         spinlock_t lock;
  61 };
  62
  63 struct snd_uac_chip {
  64         struct g_audio *audio_dev;
  65
  66         struct uac_rtd_params p_prm;
  67         struct uac_rtd_params c_prm;
  68
  69         struct snd_card *card;
  70         struct snd_pcm *pcm;
  71
  72         /* timekeeping for the playback endpoint */
  73         unsigned int p_interval;
  74         unsigned int p_residue;
  75
  76         /* pre-calculated values for playback iso completion */
  77         unsigned int p_pktsize;
  78         unsigned int p_pktsize_residue;
  79         unsigned int p_framesize;
  80 };
  81
  82 static const struct snd_pcm_hardware uac_pcm_hardware = {
  83         .info = SNDRV_PCM_INFO_INTERLEAVED | SNDRV_PCM_INFO_BLOCK_TRANSFER
  84                  | SNDRV_PCM_INFO_MMAP | SNDRV_PCM_INFO_MMAP_VALID
  85                  | SNDRV_PCM_INFO_PAUSE | SNDRV_PCM_INFO_RESUME,
  86         .rates = SNDRV_PCM_RATE_CONTINUOUS,
  87         .periods_max = BUFF_SIZE_MAX / PRD_SIZE_MAX,
  88         .buffer_bytes_max = BUFF_SIZE_MAX,
  89         .period_bytes_max = PRD_SIZE_MAX,
  90         .periods_min = MIN_PERIODS,
  91 };
  92
  93 static void u_audio_iso_complete(struct usb_ep *ep, struct usb_request *req)
  94 {
  95         unsigned pending;
  96         unsigned long flags;
  97         unsigned int hw_ptr;
  98         bool update_alsa = false;
  99         int status = req->status;
 100         struct uac_req *ur = req->context;
 101         struct snd_pcm_substream *substream;
 102         struct uac_rtd_params *prm = ur->pp;
 103         struct snd_uac_chip *uac = prm->uac;
 104
 105         /* i/f shutting down */
 106         if (!prm->ep_enabled || req->status == -ESHUTDOWN)
 107                 return;
 108
 109         /*
 110          * We can't really do much about bad xfers.
 111          * Afterall, the ISOCH xfers could fail legitimately.
 112          */
 113         if (status)
 114                 pr_debug("%s: iso_complete status(%d) %d/%d\n",
 115                         __func__, status, req->actual, req->length);
 116
 117         substream = prm->ss;
 118
 119         /* Do nothing if ALSA isn't active */
 120         if (!substream)
 121                 goto exit;
 122
 123         spin_lock_irqsave(&prm->lock, flags);
 124
 125         if (substream->stream == SNDRV_PCM_STREAM_PLAYBACK) {
 126                 /*
 127                  * For each IN packet, take the quotient of the current data
 128                  * rate and the endpoint's interval as the base packet size.
 129                  * If there is a residue from this division, add it to the
 130                  * residue accumulator.
 131                  */
 132                 req->length = uac->p_pktsize;
 133                 uac->p_residue += uac->p_pktsize_residue;
 134
 135                 /*
 136                  * Whenever there are more bytes in the accumulator than we
 137                  * need to add one more sample frame, increase this packet's
 138                  * size and decrease the accumulator.
 139                  */
 140                 if (uac->p_residue / uac->p_interval >= uac->p_framesize) {
 141                         req->length += uac->p_framesize;
 142                         uac->p_residue -= uac->p_framesize *
 143                                            uac->p_interval;
 144                 }
 145
 146                 req->actual = req->length;
 147         }
 148
 149         pending = prm->hw_ptr % prm->period_size;
 150         pending += req->actual;
 151         if (pending >= prm->period_size)
 152                 update_alsa = true;
 153
 154         hw_ptr = prm->hw_ptr;
 155         prm->hw_ptr = (prm->hw_ptr + req->actual) % prm->dma_bytes;
 156
 157         spin_unlock_irqrestore(&prm->lock, flags);
 158
 159         /* Pack USB load in ALSA ring buffer */
 160         pending = prm->dma_bytes - hw_ptr;
 161
 162         if (substream->stream == SNDRV_PCM_STREAM_PLAYBACK) {
 163                 if (unlikely(pending < req->actual)) {
 164                         memcpy(req->buf, prm->dma_area + hw_ptr, pending);
 165                         memcpy(req->buf + pending, prm->dma_area,
 166                                req->actual - pending);
 167                 } else {
 168                         memcpy(req->buf, prm->dma_area + hw_ptr, req->actual);
 169                 }
 170         } else {
 171                 if (unlikely(pending < req->actual)) {
 172                         memcpy(prm->dma_area + hw_ptr, req->buf, pending);
 173                         memcpy(prm->dma_area, req->buf + pending,
 174                                req->actual - pending);
 175                 } else {
 176                         memcpy(prm->dma_area + hw_ptr, req->buf, req->actual);
 177                 }
 178         }
 179
 180 exit:
 181         if (usb_ep_queue(ep, req, GFP_ATOMIC))
 182                 dev_err(uac->card->dev, "%d Error!\n", __LINE__);
 183
 184         if (update_alsa)
 185                 snd_pcm_period_elapsed(substream);
 186 }
 187
 188 static int uac_pcm_trigger(struct snd_pcm_substream *substream, int cmd)
 189 {
 190         struct snd_uac_chip *uac = snd_pcm_substream_chip(substream);
 191         struct uac_rtd_params *prm;
 192         struct g_audio *audio_dev;
 193         struct uac_params *params;
 194         unsigned long flags;
 195         int err = 0;
 196
 197         audio_dev = uac->audio_dev;
 198         params = &audio_dev->params;
 199
 200         if (substream->stream == SNDRV_PCM_STREAM_PLAYBACK)
 201                 prm = &uac->p_prm;
 202         else
 203                 prm = &uac->c_prm;
 204
 205         spin_lock_irqsave(&prm->lock, flags);
 206
 207         /* Reset */
 208         prm->hw_ptr = 0;
 209
 210         switch (cmd) {
 211         case SNDRV_PCM_TRIGGER_START:
 212         case SNDRV_PCM_TRIGGER_RESUME:
 213                 prm->ss = substream;
 214                 break;
 215         case SNDRV_PCM_TRIGGER_STOP:
 216         case SNDRV_PCM_TRIGGER_SUSPEND:
 217                 prm->ss = NULL;
 218                 break;
 219         default:
 220                 err = -EINVAL;
 221         }
 222
 223         spin_unlock_irqrestore(&prm->lock, flags);
 224
 225         /* Clear buffer after Play stops */
 226         if (substream->stream == SNDRV_PCM_STREAM_PLAYBACK && !prm->ss)
 227                 memset(prm->rbuf, 0, prm->max_psize * params->req_number);
 228
 229         return err;
 230 }
 231
 232 static snd_pcm_uframes_t uac_pcm_pointer(struct snd_pcm_substream *substream)
 233 {
 234         struct snd_uac_chip *uac = snd_pcm_substream_chip(substream);
 235         struct uac_rtd_params *prm;
 236
 237         if (substream->stream == SNDRV_PCM_STREAM_PLAYBACK)
 238                 prm = &uac->p_prm;
 239         else
 240                 prm = &uac->c_prm;
 241
 242         return bytes_to_frames(substream->runtime, prm->hw_ptr);
 243 }
 244
 245 static int uac_pcm_hw_params(struct snd_pcm_substream *substream,
 246                                struct snd_pcm_hw_params *hw_params)
 247 {
 248         struct snd_uac_chip *uac = snd_pcm_substream_chip(substream);
 249         struct uac_rtd_params *prm;
 250         int err;
 251
 252         if (substream->stream == SNDRV_PCM_STREAM_PLAYBACK)
 253                 prm = &uac->p_prm;
 254         else
 255                 prm = &uac->c_prm;
 256
 257         err = snd_pcm_lib_malloc_pages(substream,
 258                                         params_buffer_bytes(hw_params));
 259         if (err >= 0) {
 260                 prm->dma_bytes = substream->runtime->dma_bytes;
 261                 prm->dma_area = substream->runtime->dma_area;
 262                 prm->period_size = params_period_bytes(hw_params);
 263         }
 264
 265         return err;
 266 }
 267
 268 static int uac_pcm_hw_free(struct snd_pcm_substream *substream)
 269 {
 270         struct snd_uac_chip *uac = snd_pcm_substream_chip(substream);
 271         struct uac_rtd_params *prm;
 272
 273         if (substream->stream == SNDRV_PCM_STREAM_PLAYBACK)
 274                 prm = &uac->p_prm;
 275         else
 276                 prm = &uac->c_prm;
 277
 278         prm->dma_area = NULL;
 279         prm->dma_bytes = 0;
 280         prm->period_size = 0;
 281
 282         return snd_pcm_lib_free_pages(substream);
 283 }
 284
 285 static int uac_pcm_open(struct snd_pcm_substream *substream)
 286 {
 287         struct snd_uac_chip *uac = snd_pcm_substream_chip(substream);
 288         struct snd_pcm_runtime *runtime = substream->runtime;
 289         struct g_audio *audio_dev;
 290         struct uac_params *params;
 291         int p_ssize, c_ssize;
 292         int p_srate, c_srate;
 293         int p_chmask, c_chmask;
 294
 295         audio_dev = uac->audio_dev;
 296         params = &audio_dev->params;
 297         p_ssize = params->p_ssize;
 298         c_ssize = params->c_ssize;
 299         p_srate = params->p_srate;
 300         c_srate = params->c_srate;
 301         p_chmask = params->p_chmask;
 302         c_chmask = params->c_chmask;
 303         uac->p_residue = 0;
 304
 305         runtime->hw = uac_pcm_hardware;
 306
 307         if (substream->stream == SNDRV_PCM_STREAM_PLAYBACK) {
 308                 spin_lock_init(&uac->p_prm.lock);
 309                 runtime->hw.rate_min = p_srate;
 310                 switch (p_ssize) {
 311                 case 3:
 312                         runtime->hw.formats = SNDRV_PCM_FMTBIT_S24_3LE;
 313                         break;
 314                 case 4:
 315                         runtime->hw.formats = SNDRV_PCM_FMTBIT_S32_LE;
 316                         break;
 317                 default:
 318                         runtime->hw.formats = SNDRV_PCM_FMTBIT_S16_LE;
 319                         break;
 320                 }
 321                 runtime->hw.channels_min = num_channels(p_chmask);
 322                 runtime->hw.period_bytes_min = 2 * uac->p_prm.max_psize
 323                                                 / runtime->hw.periods_min;
 324         } else {
 325                 spin_lock_init(&uac->c_prm.lock);
 326                 runtime->hw.rate_min = c_srate;
 327                 switch (c_ssize) {
 328                 case 3:
 329                         runtime->hw.formats = SNDRV_PCM_FMTBIT_S24_3LE;
 330                         break;
 331                 case 4:
 332                         runtime->hw.formats = SNDRV_PCM_FMTBIT_S32_LE;
 333                         break;
 334                 default:
 335                         runtime->hw.formats = SNDRV_PCM_FMTBIT_S16_LE;
 336                         break;
 337                 }
 338                 runtime->hw.channels_min = num_channels(c_chmask);
 339                 runtime->hw.period_bytes_min = 2 * uac->c_prm.max_psize
 340                                                 / runtime->hw.periods_min;
 341         }
 342
 343         runtime->hw.rate_max = runtime->hw.rate_min;
 344         runtime->hw.channels_max = runtime->hw.channels_min;
 345
 346         snd_pcm_hw_constraint_integer(runtime, SNDRV_PCM_HW_PARAM_PERIODS);
 347
 348         return 0;
 349 }
 350
 351 /* ALSA cries without these function pointers */
 352 static int uac_pcm_null(struct snd_pcm_substream *substream)
 353 {
 354         return 0;
 355 }
 356
 357 static const struct snd_pcm_ops uac_pcm_ops = {
 358         .open = uac_pcm_open,
 359         .close = uac_pcm_null,
 360         .ioctl = snd_pcm_lib_ioctl,
 361         .hw_params = uac_pcm_hw_params,
 362         .hw_free = uac_pcm_hw_free,
 363         .trigger = uac_pcm_trigger,
 364         .pointer = uac_pcm_pointer,
 365         .prepare = uac_pcm_null,
 366 };
 367
 368 static inline void free_ep(struct uac_rtd_params *prm, struct usb_ep *ep)
 369 {
 370         struct snd_uac_chip *uac = prm->uac;
 371         struct g_audio *audio_dev;
 372         struct uac_params *params;
 373         int i;
 374
 375         if (!prm->ep_enabled)
 376                 return;
 377
 378         prm->ep_enabled = false;
 379
 380         audio_dev = uac->audio_dev;
 381         params = &audio_dev->params;
 382
 383         for (i = 0; i < params->req_number; i++) {
 384                 if (prm->ureq[i].req) {
 385                         usb_ep_dequeue(ep, prm->ureq[i].req);
 386                         usb_ep_free_request(ep, prm->ureq[i].req);
 387                         prm->ureq[i].req = NULL;
 388                 }
 389         }
 390
 391         if (usb_ep_disable(ep))
 392                 dev_err(uac->card->dev, "%s:%d Error!\n", __func__, __LINE__);
 393 }
 394
 395
 396 int u_audio_start_capture(struct g_audio *audio_dev)
 397 {
 398         struct snd_uac_chip *uac = audio_dev->uac;
 399         struct usb_gadget *gadget = audio_dev->gadget;
 400         struct device *dev = &gadget->dev;
 401         struct usb_request *req;
 402         struct usb_ep *ep;
 403         struct uac_rtd_params *prm;
 404         struct uac_params *params = &audio_dev->params;
 405         int req_len, i;
 406
 407         ep = audio_dev->out_ep;
 408         prm = &uac->c_prm;
 409         config_ep_by_speed(gadget, &audio_dev->func, ep);
 410         req_len = prm->max_psize;
 411
 412         prm->ep_enabled = true;
 413         usb_ep_enable(ep);
 414
 415         for (i = 0; i < params->req_number; i++) {
 416                 if (!prm->ureq[i].req) {
 417                         req = usb_ep_alloc_request(ep, GFP_ATOMIC);
 418                         if (req == NULL)
 419                                 return -ENOMEM;
 420
 421                         prm->ureq[i].req = req;
 422                         prm->ureq[i].pp = prm;
 423
 424                         req->zero = 0;
 425                         req->context = &prm->ureq[i];
 426                         req->length = req_len;
 427                         req->complete = u_audio_iso_complete;
 428                         req->buf = prm->rbuf + i * prm->max_psize;
 429                 }
 430
 431                 if (usb_ep_queue(ep, prm->ureq[i].req, GFP_ATOMIC))
 432                         dev_err(dev, "%s:%d Error!\n", __func__, __LINE__);
 433         }
 434
 435         return 0;
 436 }
 437 EXPORT_SYMBOL_GPL(u_audio_start_capture);
 438
 439 void u_audio_stop_capture(struct g_audio *audio_dev)
 440 {
 441         struct snd_uac_chip *uac = audio_dev->uac;
 442
 443         free_ep(&uac->c_prm, audio_dev->out_ep);
 444 }
 445 EXPORT_SYMBOL_GPL(u_audio_stop_capture);
 446
 447 int u_audio_start_playback(struct g_audio *audio_dev)
 448 {
 449         struct snd_uac_chip *uac = audio_dev->uac;
 450         struct usb_gadget *gadget = audio_dev->gadget;
 451         struct device *dev = &gadget->dev;
 452         struct usb_request *req;
 453         struct usb_ep *ep;
 454         struct uac_rtd_params *prm;
 455         struct uac_params *params = &audio_dev->params;
 456         unsigned int factor, rate;
 457         const struct usb_endpoint_descriptor *ep_desc;
 458         int req_len, i;
 459
 460         ep = audio_dev->in_ep;
 461         prm = &uac->p_prm;
 462         config_ep_by_speed(gadget, &audio_dev->func, ep);
 463
 464         ep_desc = ep->desc;
 465
 466         /* pre-calculate the playback endpoint's interval */
 467         if (gadget->speed == USB_SPEED_FULL)
 468                 factor = 1000;
 469         else
 470                 factor = 8000;
 471
 472         /* pre-compute some values for iso_complete() */
 473         uac->p_framesize = params->p_ssize *
 474                             num_channels(params->p_chmask);
 475         rate = params->p_srate * uac->p_framesize;
 476         uac->p_interval = factor / (1 << (ep_desc->bInterval - 1));
 477         uac->p_pktsize = min_t(unsigned int, rate / uac->p_interval,
 478                                 prm->max_psize);
 479
 480         if (uac->p_pktsize < prm->max_psize)
 481                 uac->p_pktsize_residue = rate % uac->p_interval;
 482         else
 483                 uac->p_pktsize_residue = 0;
 484
 485         req_len = uac->p_pktsize;
 486         uac->p_residue = 0;
 487
 488         prm->ep_enabled = true;
 489         usb_ep_enable(ep);
 490
 491         for (i = 0; i < params->req_number; i++) {
 492                 if (!prm->ureq[i].req) {
 493                         req = usb_ep_alloc_request(ep, GFP_ATOMIC);
 494                         if (req == NULL)
 495                                 return -ENOMEM;
 496
 497                         prm->ureq[i].req = req;
 498                         prm->ureq[i].pp = prm;
 499
 500                         req->zero = 0;
 501                         req->context = &prm->ureq[i];
 502                         req->length = req_len;
 503                         req->complete = u_audio_iso_complete;
 504                         req->buf = prm->rbuf + i * prm->max_psize;
 505                 }
 506
 507                 if (usb_ep_queue(ep, prm->ureq[i].req, GFP_ATOMIC))
 508                         dev_err(dev, "%s:%d Error!\n", __func__, __LINE__);
 509         }
 510
 511         return 0;
 512 }
 513 EXPORT_SYMBOL_GPL(u_audio_start_playback);
 514
 515 void u_audio_stop_playback(struct g_audio *audio_dev)
 516 {
 517         struct snd_uac_chip *uac = audio_dev->uac;
 518
 519         free_ep(&uac->p_prm, audio_dev->in_ep);
 520 }
 521 EXPORT_SYMBOL_GPL(u_audio_stop_playback);
 522
 523 int g_audio_setup(struct g_audio *g_audio, const char *pcm_name,
 524                                         const char *card_name)
 525 {
 526         struct snd_uac_chip *uac;
 527         struct snd_card *card;
 528         struct snd_pcm *pcm;
 529         struct uac_params *params;
 530         int p_chmask, c_chmask;
 531         int err;
 532
 533         if (!g_audio)
 534                 return -EINVAL;
 535
 536         uac = kzalloc(sizeof(*uac), GFP_KERNEL);
 537         if (!uac)
 538                 return -ENOMEM;
 539         g_audio->uac = uac;
 540         uac->audio_dev = g_audio;
 541
 542         params = &g_audio->params;
 543         p_chmask = params->p_chmask;
 544         c_chmask = params->c_chmask;
 545
 546         if (c_chmask) {
 547                 struct uac_rtd_params *prm = &uac->c_prm;
 548
 549                 uac->c_prm.uac = uac;
 550                 prm->max_psize = g_audio->out_ep_maxpsize;
 551
 552                 prm->ureq = kcalloc(params->req_number, sizeof(struct uac_req),
 553                                 GFP_KERNEL);
 554                 if (!prm->ureq) {
 555                         err = -ENOMEM;
 556                         goto fail;
 557                 }
 558
 559                 prm->rbuf = kcalloc(params->req_number, prm->max_psize,
 560                                 GFP_KERNEL);
 561                 if (!prm->rbuf) {
 562                         prm->max_psize = 0;
 563                         err = -ENOMEM;
 564                         goto fail;
 565                 }
 566         }
 567
 568         if (p_chmask) {
 569                 struct uac_rtd_params *prm = &uac->p_prm;
 570
 571                 uac->p_prm.uac = uac;
 572                 prm->max_psize = g_audio->in_ep_maxpsize;
 573
 574                 prm->ureq = kcalloc(params->req_number, sizeof(struct uac_req),
 575                                 GFP_KERNEL);
 576                 if (!prm->ureq) {
 577                         err = -ENOMEM;
 578                         goto fail;
 579                 }
 580
 581                 prm->rbuf = kcalloc(params->req_number, prm->max_psize,
 582                                 GFP_KERNEL);
 583                 if (!prm->rbuf) {
 584                         prm->max_psize = 0;
 585                         err = -ENOMEM;
 586                         goto fail;
 587                 }
 588         }
 589
 590         /* Choose any slot, with no id */
 591         err = snd_card_new(&g_audio->gadget->dev,
 592                         -1, NULL, THIS_MODULE, 0, &card);
 593         if (err < 0)
 594                 goto fail;
 595
 596         uac->card = card;
 597
 598         /*
 599          * Create first PCM device
 600          * Create a substream only for non-zero channel streams
 601          */
 602         err = snd_pcm_new(uac->card, pcm_name, 0,
 603                                p_chmask ? 1 : 0, c_chmask ? 1 : 0, &pcm);
 604         if (err < 0)
 605                 goto snd_fail;
 606
 607         strcpy(pcm->name, pcm_name);
 608         pcm->private_data = uac;
 609         uac->pcm = pcm;
 610
 611         snd_pcm_set_ops(pcm, SNDRV_PCM_STREAM_PLAYBACK, &uac_pcm_ops);
 612         snd_pcm_set_ops(pcm, SNDRV_PCM_STREAM_CAPTURE, &uac_pcm_ops);
 613
 614         strcpy(card->driver, card_name);
 615         strcpy(card->shortname, card_name);
 616         sprintf(card->longname, "%s %i", card_name, card->dev->id);
 617
 618         snd_pcm_lib_preallocate_pages_for_all(pcm, SNDRV_DMA_TYPE_CONTINUOUS,
 619                 snd_dma_continuous_data(GFP_KERNEL), 0, BUFF_SIZE_MAX);
 620
 621         err = snd_card_register(card);
 622
 623         if (!err)
 624                 return 0;
 625
 626 snd_fail:
 627         snd_card_free(card);
 628 fail:
 629         kfree(uac->p_prm.ureq);
 630         kfree(uac->c_prm.ureq);
 631         kfree(uac->p_prm.rbuf);
 632         kfree(uac->c_prm.rbuf);
 633         kfree(uac);
 634
 635         return err;
 636 }
 637 EXPORT_SYMBOL_GPL(g_audio_setup);
 638
 639 void g_audio_cleanup(struct g_audio *g_audio)
 640 {
 641         struct snd_uac_chip *uac;
 642         struct snd_card *card;
 643
 644         if (!g_audio || !g_audio->uac)
 645                 return;
 646
 647         uac = g_audio->uac;
 648         card = uac->card;
 649         if (card)
 650                 snd_card_free(card);
 651
 652         kfree(uac->p_prm.ureq);
 653         kfree(uac->c_prm.ureq);
 654         kfree(uac->p_prm.rbuf);
 655         kfree(uac->c_prm.rbuf);
 656         kfree(uac);
 657 }
 658 EXPORT_SYMBOL_GPL(g_audio_cleanup);
 659
 660 MODULE_LICENSE("GPL");
 661 MODULE_DESCRIPTION("USB gadget \"ALSA sound card\" utilities");
 662 MODULE_AUTHOR("Ruslan Bilovol");