sound/usb/pcm.c

   1 // SPDX-License-Identifier: GPL-2.0-or-later
   2 /*
   3  */
   4
   5 #include <linux/init.h>
   6 #include <linux/slab.h>
   7 #include <linux/bitrev.h>
   8 #include <linux/ratelimit.h>
   9 #include <linux/usb.h>
  10 #include <linux/usb/audio.h>
  11 #include <linux/usb/audio-v2.h>
  12
  13 #include <sound/core.h>
  14 #include <sound/pcm.h>
  15 #include <sound/pcm_params.h>
  16
  17 #include "usbaudio.h"
  18 #include "card.h"
  19 #include "quirks.h"
  20 #include "endpoint.h"
  21 #include "helper.h"
  22 #include "pcm.h"
  23 #include "clock.h"
  24 #include "power.h"
  25 #include "media.h"
  26 #include "implicit.h"
  27
  28 #define SUBSTREAM_FLAG_DATA_EP_STARTED  0
  29 #define SUBSTREAM_FLAG_SYNC_EP_STARTED  1
  30
  31 /* return the estimated delay based on USB frame counters */
  32 static snd_pcm_uframes_t snd_usb_pcm_delay(struct snd_usb_substream *subs,
  33                                            struct snd_pcm_runtime *runtime)
  34 {
  35         unsigned int current_frame_number;
  36         unsigned int frame_diff;
  37         int est_delay;
  38         int queued;
  39
  40         if (subs->direction == SNDRV_PCM_STREAM_PLAYBACK) {
  41                 queued = bytes_to_frames(runtime, subs->inflight_bytes);
  42                 if (!queued)
  43                         return 0;
  44         } else if (!subs->running) {
  45                 return 0;
  46         }
  47
  48         current_frame_number = usb_get_current_frame_number(subs->dev);
  49         /*
  50          * HCD implementations use different widths, use lower 8 bits.
  51          * The delay will be managed up to 256ms, which is more than
  52          * enough
  53          */
  54         frame_diff = (current_frame_number - subs->last_frame_number) & 0xff;
  55
  56         /* Approximation based on number of samples per USB frame (ms),
  57            some truncation for 44.1 but the estimate is good enough */
  58         est_delay = frame_diff * runtime->rate / 1000;
  59
  60         if (subs->direction == SNDRV_PCM_STREAM_PLAYBACK) {
  61                 est_delay = queued - est_delay;
  62                 if (est_delay < 0)
  63                         est_delay = 0;
  64         }
  65
  66         return est_delay;
  67 }
  68
  69 /*
  70  * return the current pcm pointer.  just based on the hwptr_done value.
  71  */
  72 static snd_pcm_uframes_t snd_usb_pcm_pointer(struct snd_pcm_substream *substream)
  73 {
  74         struct snd_pcm_runtime *runtime = substream->runtime;
  75         struct snd_usb_substream *subs = runtime->private_data;
  76         unsigned int hwptr_done;
  77
  78         if (atomic_read(&subs->stream->chip->shutdown))
  79                 return SNDRV_PCM_POS_XRUN;
  80         spin_lock(&subs->lock);
  81         hwptr_done = subs->hwptr_done;
  82         runtime->delay = snd_usb_pcm_delay(subs, runtime);
  83         spin_unlock(&subs->lock);
  84         return bytes_to_frames(runtime, hwptr_done);
  85 }
  86
  87 /*
  88  * find a matching audio format
  89  */
  90 static const struct audioformat *
  91 find_format(struct list_head *fmt_list_head, snd_pcm_format_t format,
  92             unsigned int rate, unsigned int channels, bool strict_match,
  93             struct snd_usb_substream *subs)
  94 {
  95         const struct audioformat *fp;
  96         const struct audioformat *found = NULL;
  97         int cur_attr = 0, attr;
  98
  99         list_for_each_entry(fp, fmt_list_head, list) {
 100                 if (strict_match) {
 101                         if (!(fp->formats & pcm_format_to_bits(format)))
 102                                 continue;
 103                         if (fp->channels != channels)
 104                                 continue;
 105                 }
 106                 if (rate < fp->rate_min || rate > fp->rate_max)
 107                         continue;
 108                 if (!(fp->rates & SNDRV_PCM_RATE_CONTINUOUS)) {
 109                         unsigned int i;
 110                         for (i = 0; i < fp->nr_rates; i++)
 111                                 if (fp->rate_table[i] == rate)
 112                                         break;
 113                         if (i >= fp->nr_rates)
 114                                 continue;
 115                 }
 116                 attr = fp->ep_attr & USB_ENDPOINT_SYNCTYPE;
 117                 if (!found) {
 118                         found = fp;
 119                         cur_attr = attr;
 120                         continue;
 121                 }
 122                 /* avoid async out and adaptive in if the other method
 123                  * supports the same format.
 124                  * this is a workaround for the case like
 125                  * M-audio audiophile USB.
 126                  */
 127                 if (subs && attr != cur_attr) {
 128                         if ((attr == USB_ENDPOINT_SYNC_ASYNC &&
 129                              subs->direction == SNDRV_PCM_STREAM_PLAYBACK) ||
 130                             (attr == USB_ENDPOINT_SYNC_ADAPTIVE &&
 131                              subs->direction == SNDRV_PCM_STREAM_CAPTURE))
 132                                 continue;
 133                         if ((cur_attr == USB_ENDPOINT_SYNC_ASYNC &&
 134                              subs->direction == SNDRV_PCM_STREAM_PLAYBACK) ||
 135                             (cur_attr == USB_ENDPOINT_SYNC_ADAPTIVE &&
 136                              subs->direction == SNDRV_PCM_STREAM_CAPTURE)) {
 137                                 found = fp;
 138                                 cur_attr = attr;
 139                                 continue;
 140                         }
 141                 }
 142                 /* find the format with the largest max. packet size */
 143                 if (fp->maxpacksize > found->maxpacksize) {
 144                         found = fp;
 145                         cur_attr = attr;
 146                 }
 147         }
 148         return found;
 149 }
 150
 151 static const struct audioformat *
 152 find_substream_format(struct snd_usb_substream *subs,
 153                       const struct snd_pcm_hw_params *params)
 154 {
 155         return find_format(&subs->fmt_list, params_format(params),
 156                            params_rate(params), params_channels(params),
 157                            true, subs);
 158 }
 159
 160 bool snd_usb_pcm_has_fixed_rate(struct snd_usb_substream *subs)
 161 {
 162         const struct audioformat *fp;
 163         struct snd_usb_audio *chip;
 164         int rate = -1;
 165
 166         if (!subs)
 167                 return false;
 168         chip = subs->stream->chip;
 169         if (!(chip->quirk_flags & QUIRK_FLAG_FIXED_RATE))
 170                 return false;
 171         list_for_each_entry(fp, &subs->fmt_list, list) {
 172                 if (fp->rates & SNDRV_PCM_RATE_CONTINUOUS)
 173                         return false;
 174                 if (fp->nr_rates < 1)
 175                         continue;
 176                 if (fp->nr_rates > 1)
 177                         return false;
 178                 if (rate < 0) {
 179                         rate = fp->rate_table[0];
 180                         continue;
 181                 }
 182                 if (rate != fp->rate_table[0])
 183                         return false;
 184         }
 185         return true;
 186 }
 187
 188 static int init_pitch_v1(struct snd_usb_audio *chip, int ep)
 189 {
 190         struct usb_device *dev = chip->dev;
 191         unsigned char data[1];
 192         int err;
 193
 194         data[0] = 1;
 195         err = snd_usb_ctl_msg(dev, usb_sndctrlpipe(dev, 0), UAC_SET_CUR,
 196                               USB_TYPE_CLASS|USB_RECIP_ENDPOINT|USB_DIR_OUT,
 197                               UAC_EP_CS_ATTR_PITCH_CONTROL << 8, ep,
 198                               data, sizeof(data));
 199         return err;
 200 }
 201
 202 static int init_pitch_v2(struct snd_usb_audio *chip, int ep)
 203 {
 204         struct usb_device *dev = chip->dev;
 205         unsigned char data[1];
 206         int err;
 207
 208         data[0] = 1;
 209         err = snd_usb_ctl_msg(dev, usb_sndctrlpipe(dev, 0), UAC2_CS_CUR,
 210                               USB_TYPE_CLASS | USB_RECIP_ENDPOINT | USB_DIR_OUT,
 211                               UAC2_EP_CS_PITCH << 8, 0,
 212                               data, sizeof(data));
 213         return err;
 214 }
 215
 216 /*
 217  * initialize the pitch control and sample rate
 218  */
 219 int snd_usb_init_pitch(struct snd_usb_audio *chip,
 220                        const struct audioformat *fmt)
 221 {
 222         int err;
 223
 224         /* if endpoint doesn't have pitch control, bail out */
 225         if (!(fmt->attributes & UAC_EP_CS_ATTR_PITCH_CONTROL))
 226                 return 0;
 227
 228         usb_audio_dbg(chip, "enable PITCH for EP 0x%x\n", fmt->endpoint);
 229
 230         switch (fmt->protocol) {
 231         case UAC_VERSION_1:
 232                 err = init_pitch_v1(chip, fmt->endpoint);
 233                 break;
 234         case UAC_VERSION_2:
 235                 err = init_pitch_v2(chip, fmt->endpoint);
 236                 break;
 237         default:
 238                 return 0;
 239         }
 240
 241         if (err < 0) {
 242                 usb_audio_err(chip, "failed to enable PITCH for EP 0x%x\n",
 243                               fmt->endpoint);
 244                 return err;
 245         }
 246
 247         return 0;
 248 }
 249
 250 static bool stop_endpoints(struct snd_usb_substream *subs, bool keep_pending)
 251 {
 252         bool stopped = 0;
 253
 254         if (test_and_clear_bit(SUBSTREAM_FLAG_SYNC_EP_STARTED, &subs->flags)) {
 255                 snd_usb_endpoint_stop(subs->sync_endpoint, keep_pending);
 256                 stopped = true;
 257         }
 258         if (test_and_clear_bit(SUBSTREAM_FLAG_DATA_EP_STARTED, &subs->flags)) {
 259                 snd_usb_endpoint_stop(subs->data_endpoint, keep_pending);
 260                 stopped = true;
 261         }
 262         return stopped;
 263 }
 264
 265 static int start_endpoints(struct snd_usb_substream *subs)
 266 {
 267         int err;
 268
 269         if (!subs->data_endpoint)
 270                 return -EINVAL;
 271
 272         if (!test_and_set_bit(SUBSTREAM_FLAG_DATA_EP_STARTED, &subs->flags)) {
 273                 err = snd_usb_endpoint_start(subs->data_endpoint);
 274                 if (err < 0) {
 275                         clear_bit(SUBSTREAM_FLAG_DATA_EP_STARTED, &subs->flags);
 276                         goto error;
 277                 }
 278         }
 279
 280         if (subs->sync_endpoint &&
 281             !test_and_set_bit(SUBSTREAM_FLAG_SYNC_EP_STARTED, &subs->flags)) {
 282                 err = snd_usb_endpoint_start(subs->sync_endpoint);
 283                 if (err < 0) {
 284                         clear_bit(SUBSTREAM_FLAG_SYNC_EP_STARTED, &subs->flags);
 285                         goto error;
 286                 }
 287         }
 288
 289         return 0;
 290
 291  error:
 292         stop_endpoints(subs, false);
 293         return err;
 294 }
 295
 296 static void sync_pending_stops(struct snd_usb_substream *subs)
 297 {
 298         snd_usb_endpoint_sync_pending_stop(subs->sync_endpoint);
 299         snd_usb_endpoint_sync_pending_stop(subs->data_endpoint);
 300 }
 301
 302 /* PCM sync_stop callback */
 303 static int snd_usb_pcm_sync_stop(struct snd_pcm_substream *substream)
 304 {
 305         struct snd_usb_substream *subs = substream->runtime->private_data;
 306
 307         sync_pending_stops(subs);
 308         return 0;
 309 }
 310
 311 /* Set up sync endpoint */
 312 int snd_usb_audioformat_set_sync_ep(struct snd_usb_audio *chip,
 313                                     struct audioformat *fmt)
 314 {
 315         struct usb_device *dev = chip->dev;
 316         struct usb_host_interface *alts;
 317         struct usb_interface_descriptor *altsd;
 318         unsigned int ep, attr, sync_attr;
 319         bool is_playback;
 320         int err;
 321
 322         if (fmt->sync_ep)
 323                 return 0; /* already set up */
 324
 325         alts = snd_usb_get_host_interface(chip, fmt->iface, fmt->altsetting);
 326         if (!alts)
 327                 return 0;
 328         altsd = get_iface_desc(alts);
 329
 330         err = snd_usb_parse_implicit_fb_quirk(chip, fmt, alts);
 331         if (err > 0)
 332                 return 0; /* matched */
 333
 334         /*
 335          * Generic sync EP handling
 336          */
 337
 338         if (fmt->ep_idx > 0 || altsd->bNumEndpoints < 2)
 339                 return 0;
 340
 341         is_playback = !(get_endpoint(alts, 0)->bEndpointAddress & USB_DIR_IN);
 342         attr = fmt->ep_attr & USB_ENDPOINT_SYNCTYPE;
 343         if ((is_playback && (attr == USB_ENDPOINT_SYNC_SYNC ||
 344                              attr == USB_ENDPOINT_SYNC_ADAPTIVE)) ||
 345             (!is_playback && attr != USB_ENDPOINT_SYNC_ADAPTIVE))
 346                 return 0;
 347
 348         sync_attr = get_endpoint(alts, 1)->bmAttributes;
 349
 350         /*
 351          * In case of illegal SYNC_NONE for OUT endpoint, we keep going to see
 352          * if we don't find a sync endpoint, as on M-Audio Transit. In case of
 353          * error fall back to SYNC mode and don't create sync endpoint
 354          */
 355
 356         /* check sync-pipe endpoint */
 357         /* ... and check descriptor size before accessing bSynchAddress
 358            because there is a version of the SB Audigy 2 NX firmware lacking
 359            the audio fields in the endpoint descriptors */
 360         if ((sync_attr & USB_ENDPOINT_XFERTYPE_MASK) != USB_ENDPOINT_XFER_ISOC ||
 361             (get_endpoint(alts, 1)->bLength >= USB_DT_ENDPOINT_AUDIO_SIZE &&
 362              get_endpoint(alts, 1)->bSynchAddress != 0)) {
 363                 dev_err(&dev->dev,
 364                         "%d:%d : invalid sync pipe. bmAttributes %02x, bLength %d, bSynchAddress %02x\n",
 365                            fmt->iface, fmt->altsetting,
 366                            get_endpoint(alts, 1)->bmAttributes,
 367                            get_endpoint(alts, 1)->bLength,
 368                            get_endpoint(alts, 1)->bSynchAddress);
 369                 if (is_playback && attr == USB_ENDPOINT_SYNC_NONE)
 370                         return 0;
 371                 return -EINVAL;
 372         }
 373         ep = get_endpoint(alts, 1)->bEndpointAddress;
 374         if (get_endpoint(alts, 0)->bLength >= USB_DT_ENDPOINT_AUDIO_SIZE &&
 375             get_endpoint(alts, 0)->bSynchAddress != 0 &&
 376             ((is_playback && ep != (unsigned int)(get_endpoint(alts, 0)->bSynchAddress | USB_DIR_IN)) ||
 377              (!is_playback && ep != (unsigned int)(get_endpoint(alts, 0)->bSynchAddress & ~USB_DIR_IN)))) {
 378                 dev_err(&dev->dev,
 379                         "%d:%d : invalid sync pipe. is_playback %d, ep %02x, bSynchAddress %02x\n",
 380                            fmt->iface, fmt->altsetting,
 381                            is_playback, ep, get_endpoint(alts, 0)->bSynchAddress);
 382                 if (is_playback && attr == USB_ENDPOINT_SYNC_NONE)
 383                         return 0;
 384                 return -EINVAL;
 385         }
 386
 387         fmt->sync_ep = ep;
 388         fmt->sync_iface = altsd->bInterfaceNumber;
 389         fmt->sync_altsetting = altsd->bAlternateSetting;
 390         fmt->sync_ep_idx = 1;
 391         if ((sync_attr & USB_ENDPOINT_USAGE_MASK) == USB_ENDPOINT_USAGE_IMPLICIT_FB)
 392                 fmt->implicit_fb = 1;
 393
 394         dev_dbg(&dev->dev, "%d:%d: found sync_ep=0x%x, iface=%d, alt=%d, implicit_fb=%d\n",
 395                 fmt->iface, fmt->altsetting, fmt->sync_ep, fmt->sync_iface,
 396                 fmt->sync_altsetting, fmt->implicit_fb);
 397
 398         return 0;
 399 }
 400
 401 static int snd_usb_pcm_change_state(struct snd_usb_substream *subs, int state)
 402 {
 403         int ret;
 404
 405         if (!subs->str_pd)
 406                 return 0;
 407
 408         ret = snd_usb_power_domain_set(subs->stream->chip, subs->str_pd, state);
 409         if (ret < 0) {
 410                 dev_err(&subs->dev->dev,
 411                         "Cannot change Power Domain ID: %d to state: %d. Err: %d\n",
 412                         subs->str_pd->pd_id, state, ret);
 413                 return ret;
 414         }
 415
 416         return 0;
 417 }
 418
 419 int snd_usb_pcm_suspend(struct snd_usb_stream *as)
 420 {
 421         int ret;
 422
 423         ret = snd_usb_pcm_change_state(&as->substream[0], UAC3_PD_STATE_D2);
 424         if (ret < 0)
 425                 return ret;
 426
 427         ret = snd_usb_pcm_change_state(&as->substream[1], UAC3_PD_STATE_D2);
 428         if (ret < 0)
 429                 return ret;
 430
 431         return 0;
 432 }
 433
 434 int snd_usb_pcm_resume(struct snd_usb_stream *as)
 435 {
 436         int ret;
 437
 438         ret = snd_usb_pcm_change_state(&as->substream[0], UAC3_PD_STATE_D1);
 439         if (ret < 0)
 440                 return ret;
 441
 442         ret = snd_usb_pcm_change_state(&as->substream[1], UAC3_PD_STATE_D1);
 443         if (ret < 0)
 444                 return ret;
 445
 446         return 0;
 447 }
 448
 449 static void close_endpoints(struct snd_usb_audio *chip,
 450                             struct snd_usb_substream *subs)
 451 {
 452         if (subs->data_endpoint) {
 453                 snd_usb_endpoint_set_sync(chip, subs->data_endpoint, NULL);
 454                 snd_usb_endpoint_close(chip, subs->data_endpoint);
 455                 subs->data_endpoint = NULL;
 456         }
 457
 458         if (subs->sync_endpoint) {
 459                 snd_usb_endpoint_close(chip, subs->sync_endpoint);
 460                 subs->sync_endpoint = NULL;
 461         }
 462 }
 463
 464 /*
 465  * hw_params callback
 466  *
 467  * allocate a buffer and set the given audio format.
 468  *
 469  * so far we use a physically linear buffer although packetize transfer
 470  * doesn't need a continuous area.
 471  * if sg buffer is supported on the later version of alsa, we'll follow
 472  * that.
 473  */
 474 static int snd_usb_hw_params(struct snd_pcm_substream *substream,
 475                              struct snd_pcm_hw_params *hw_params)
 476 {
 477         struct snd_usb_substream *subs = substream->runtime->private_data;
 478         struct snd_usb_audio *chip = subs->stream->chip;
 479         const struct audioformat *fmt;
 480         const struct audioformat *sync_fmt;
 481         bool fixed_rate, sync_fixed_rate;
 482         int ret;
 483
 484         ret = snd_media_start_pipeline(subs);
 485         if (ret)
 486                 return ret;
 487
 488         fixed_rate = snd_usb_pcm_has_fixed_rate(subs);
 489         fmt = find_substream_format(subs, hw_params);
 490         if (!fmt) {
 491                 usb_audio_dbg(chip,
 492                               "cannot find format: format=%s, rate=%d, channels=%d\n",
 493                               snd_pcm_format_name(params_format(hw_params)),
 494                               params_rate(hw_params), params_channels(hw_params));
 495                 ret = -EINVAL;
 496                 goto stop_pipeline;
 497         }
 498
 499         if (fmt->implicit_fb) {
 500                 sync_fmt = snd_usb_find_implicit_fb_sync_format(chip, fmt,
 501                                                                 hw_params,
 502                                                                 !substream->stream,
 503                                                                 &sync_fixed_rate);
 504                 if (!sync_fmt) {
 505                         usb_audio_dbg(chip,
 506                                       "cannot find sync format: ep=0x%x, iface=%d:%d, format=%s, rate=%d, channels=%d\n",
 507                                       fmt->sync_ep, fmt->sync_iface,
 508                                       fmt->sync_altsetting,
 509                                       snd_pcm_format_name(params_format(hw_params)),
 510                                       params_rate(hw_params), params_channels(hw_params));
 511                         ret = -EINVAL;
 512                         goto stop_pipeline;
 513                 }
 514         } else {
 515                 sync_fmt = fmt;
 516                 sync_fixed_rate = fixed_rate;
 517         }
 518
 519         ret = snd_usb_lock_shutdown(chip);
 520         if (ret < 0)
 521                 goto stop_pipeline;
 522
 523         ret = snd_usb_pcm_change_state(subs, UAC3_PD_STATE_D0);
 524         if (ret < 0)
 525                 goto unlock;
 526
 527         if (subs->data_endpoint) {
 528                 if (snd_usb_endpoint_compatible(chip, subs->data_endpoint,
 529                                                 fmt, hw_params))
 530                         goto unlock;
 531                 if (stop_endpoints(subs, false))
 532                         sync_pending_stops(subs);
 533                 close_endpoints(chip, subs);
 534         }
 535
 536         subs->data_endpoint = snd_usb_endpoint_open(chip, fmt, hw_params, false, fixed_rate);
 537         if (!subs->data_endpoint) {
 538                 ret = -EINVAL;
 539                 goto unlock;
 540         }
 541
 542         if (fmt->sync_ep) {
 543                 subs->sync_endpoint = snd_usb_endpoint_open(chip, sync_fmt,
 544                                                             hw_params,
 545                                                             fmt == sync_fmt,
 546                                                             sync_fixed_rate);
 547                 if (!subs->sync_endpoint) {
 548                         ret = -EINVAL;
 549                         goto unlock;
 550                 }
 551
 552                 snd_usb_endpoint_set_sync(chip, subs->data_endpoint,
 553                                           subs->sync_endpoint);
 554         }
 555
 556         mutex_lock(&chip->mutex);
 557         subs->cur_audiofmt = fmt;
 558         mutex_unlock(&chip->mutex);
 559
 560         if (!subs->data_endpoint->need_setup)
 561                 goto unlock;
 562
 563         if (subs->sync_endpoint) {
 564                 ret = snd_usb_endpoint_set_params(chip, subs->sync_endpoint);
 565                 if (ret < 0)
 566                         goto unlock;
 567         }
 568
 569         ret = snd_usb_endpoint_set_params(chip, subs->data_endpoint);
 570
 571  unlock:
 572         if (ret < 0)
 573                 close_endpoints(chip, subs);
 574
 575         snd_usb_unlock_shutdown(chip);
 576  stop_pipeline:
 577         if (ret < 0)
 578                 snd_media_stop_pipeline(subs);
 579
 580         return ret;
 581 }
 582
 583 /*
 584  * hw_free callback
 585  *
 586  * reset the audio format and release the buffer
 587  */
 588 static int snd_usb_hw_free(struct snd_pcm_substream *substream)
 589 {
 590         struct snd_usb_substream *subs = substream->runtime->private_data;
 591         struct snd_usb_audio *chip = subs->stream->chip;
 592
 593         snd_media_stop_pipeline(subs);
 594         mutex_lock(&chip->mutex);
 595         subs->cur_audiofmt = NULL;
 596         mutex_unlock(&chip->mutex);
 597         if (!snd_usb_lock_shutdown(chip)) {
 598                 if (stop_endpoints(subs, false))
 599                         sync_pending_stops(subs);
 600                 close_endpoints(chip, subs);
 601                 snd_usb_unlock_shutdown(chip);
 602         }
 603
 604         return 0;
 605 }
 606
 607 /* free-wheeling mode? (e.g. dmix) */
 608 static int in_free_wheeling_mode(struct snd_pcm_runtime *runtime)
 609 {
 610         return runtime->stop_threshold > runtime->buffer_size;
 611 }
 612
 613 /* check whether early start is needed for playback stream */
 614 static int lowlatency_playback_available(struct snd_pcm_runtime *runtime,
 615                                          struct snd_usb_substream *subs)
 616 {
 617         struct snd_usb_audio *chip = subs->stream->chip;
 618
 619         if (subs->direction == SNDRV_PCM_STREAM_CAPTURE)
 620                 return false;
 621         /* disabled via module option? */
 622         if (!chip->lowlatency)
 623                 return false;
 624         if (in_free_wheeling_mode(runtime))
 625                 return false;
 626         /* implicit feedback mode has own operation mode */
 627         if (snd_usb_endpoint_implicit_feedback_sink(subs->data_endpoint))
 628                 return false;
 629         return true;
 630 }
 631
 632 /*
 633  * prepare callback
 634  *
 635  * only a few subtle things...
 636  */
 637 static int snd_usb_pcm_prepare(struct snd_pcm_substream *substream)
 638 {
 639         struct snd_pcm_runtime *runtime = substream->runtime;
 640         struct snd_usb_substream *subs = runtime->private_data;
 641         struct snd_usb_audio *chip = subs->stream->chip;
 642         int retry = 0;
 643         int ret;
 644
 645         ret = snd_usb_lock_shutdown(chip);
 646         if (ret < 0)
 647                 return ret;
 648         if (snd_BUG_ON(!subs->data_endpoint)) {
 649                 ret = -EIO;
 650                 goto unlock;
 651         }
 652
 653  again:
 654         if (subs->sync_endpoint) {
 655                 ret = snd_usb_endpoint_prepare(chip, subs->sync_endpoint);
 656                 if (ret < 0)
 657                         goto unlock;
 658         }
 659
 660         ret = snd_usb_endpoint_prepare(chip, subs->data_endpoint);
 661         if (ret < 0)
 662                 goto unlock;
 663         else if (ret > 0)
 664                 snd_usb_set_format_quirk(subs, subs->cur_audiofmt);
 665         ret = 0;
 666
 667         /* reset the pointer */
 668         subs->buffer_bytes = frames_to_bytes(runtime, runtime->buffer_size);
 669         subs->inflight_bytes = 0;
 670         subs->hwptr_done = 0;
 671         subs->transfer_done = 0;
 672         subs->last_frame_number = 0;
 673         subs->period_elapsed_pending = 0;
 674         runtime->delay = 0;
 675
 676         subs->lowlatency_playback = lowlatency_playback_available(runtime, subs);
 677         if (substream->stream == SNDRV_PCM_STREAM_PLAYBACK &&
 678             !subs->lowlatency_playback) {
 679                 ret = start_endpoints(subs);
 680                 /* if XRUN happens at starting streams (possibly with implicit
 681                  * fb case), restart again, but only try once.
 682                  */
 683                 if (ret == -EPIPE && !retry++) {
 684                         sync_pending_stops(subs);
 685                         goto again;
 686                 }
 687         }
 688  unlock:
 689         snd_usb_unlock_shutdown(chip);
 690         return ret;
 691 }
 692
 693 /*
 694  * h/w constraints
 695  */
 696
 697 #ifdef HW_CONST_DEBUG
 698 #define hwc_debug(fmt, args...) pr_debug(fmt, ##args)
 699 #else
 700 #define hwc_debug(fmt, args...) do { } while(0)
 701 #endif
 702
 703 static const struct snd_pcm_hardware snd_usb_hardware =
 704 {
 705         .info =                 SNDRV_PCM_INFO_MMAP |
 706                                 SNDRV_PCM_INFO_MMAP_VALID |
 707                                 SNDRV_PCM_INFO_BATCH |
 708                                 SNDRV_PCM_INFO_INTERLEAVED |
 709                                 SNDRV_PCM_INFO_BLOCK_TRANSFER |
 710                                 SNDRV_PCM_INFO_PAUSE,
 711         .channels_min =         1,
 712         .channels_max =         256,
 713         .buffer_bytes_max =     INT_MAX, /* limited by BUFFER_TIME later */
 714         .period_bytes_min =     64,
 715         .period_bytes_max =     INT_MAX, /* limited by PERIOD_TIME later */
 716         .periods_min =          2,
 717         .periods_max =          1024,
 718 };
 719
 720 static int hw_check_valid_format(struct snd_usb_substream *subs,
 721                                  struct snd_pcm_hw_params *params,
 722                                  const struct audioformat *fp)
 723 {
 724         struct snd_interval *it = hw_param_interval(params, SNDRV_PCM_HW_PARAM_RATE);
 725         struct snd_interval *ct = hw_param_interval(params, SNDRV_PCM_HW_PARAM_CHANNELS);
 726         struct snd_mask *fmts = hw_param_mask(params, SNDRV_PCM_HW_PARAM_FORMAT);
 727         struct snd_interval *pt = hw_param_interval(params, SNDRV_PCM_HW_PARAM_PERIOD_TIME);
 728         struct snd_mask check_fmts;
 729         unsigned int ptime;
 730
 731         /* check the format */
 732         snd_mask_none(&check_fmts);
 733         check_fmts.bits[0] = (u32)fp->formats;
 734         check_fmts.bits[1] = (u32)(fp->formats >> 32);
 735         snd_mask_intersect(&check_fmts, fmts);
 736         if (snd_mask_empty(&check_fmts)) {
 737                 hwc_debug("   > check: no supported format 0x%llx\n", fp->formats);
 738                 return 0;
 739         }
 740         /* check the channels */
 741         if (fp->channels < ct->min || fp->channels > ct->max) {
 742                 hwc_debug("   > check: no valid channels %d (%d/%d)\n", fp->channels, ct->min, ct->max);
 743                 return 0;
 744         }
 745         /* check the rate is within the range */
 746         if (fp->rate_min > it->max || (fp->rate_min == it->max && it->openmax)) {
 747                 hwc_debug("   > check: rate_min %d > max %d\n", fp->rate_min, it->max);
 748                 return 0;
 749         }
 750         if (fp->rate_max < it->min || (fp->rate_max == it->min && it->openmin)) {
 751                 hwc_debug("   > check: rate_max %d < min %d\n", fp->rate_max, it->min);
 752                 return 0;
 753         }
 754         /* check whether the period time is >= the data packet interval */
 755         if (subs->speed != USB_SPEED_FULL) {
 756                 ptime = 125 * (1 << fp->datainterval);
 757                 if (ptime > pt->max || (ptime == pt->max && pt->openmax)) {
 758                         hwc_debug("   > check: ptime %u > max %u\n", ptime, pt->max);
 759                         return 0;
 760                 }
 761         }
 762         return 1;
 763 }
 764
 765 static int apply_hw_params_minmax(struct snd_interval *it, unsigned int rmin,
 766                                   unsigned int rmax)
 767 {
 768         int changed;
 769
 770         if (rmin > rmax) {
 771                 hwc_debug("  --> get empty\n");
 772                 it->empty = 1;
 773                 return -EINVAL;
 774         }
 775
 776         changed = 0;
 777         if (it->min < rmin) {
 778                 it->min = rmin;
 779                 it->openmin = 0;
 780                 changed = 1;
 781         }
 782         if (it->max > rmax) {
 783                 it->max = rmax;
 784                 it->openmax = 0;
 785                 changed = 1;
 786         }
 787         if (snd_interval_checkempty(it)) {
 788                 it->empty = 1;
 789                 return -EINVAL;
 790         }
 791         hwc_debug("  --> (%d, %d) (changed = %d)\n", it->min, it->max, changed);
 792         return changed;
 793 }
 794
 795 /* get the specified endpoint object that is being used by other streams
 796  * (i.e. the parameter is locked)
 797  */
 798 static const struct snd_usb_endpoint *
 799 get_endpoint_in_use(struct snd_usb_audio *chip, int endpoint,
 800                     const struct snd_usb_endpoint *ref_ep)
 801 {
 802         const struct snd_usb_endpoint *ep;
 803
 804         ep = snd_usb_get_endpoint(chip, endpoint);
 805         if (ep && ep->cur_audiofmt && (ep != ref_ep || ep->opened > 1))
 806                 return ep;
 807         return NULL;
 808 }
 809
 810 static int hw_rule_rate(struct snd_pcm_hw_params *params,
 811                         struct snd_pcm_hw_rule *rule)
 812 {
 813         struct snd_usb_substream *subs = rule->private;
 814         struct snd_usb_audio *chip = subs->stream->chip;
 815         const struct snd_usb_endpoint *ep;
 816         const struct audioformat *fp;
 817         struct snd_interval *it = hw_param_interval(params, SNDRV_PCM_HW_PARAM_RATE);
 818         unsigned int rmin, rmax, r;
 819         int i;
 820
 821         hwc_debug("hw_rule_rate: (%d,%d)\n", it->min, it->max);
 822         rmin = UINT_MAX;
 823         rmax = 0;
 824         list_for_each_entry(fp, &subs->fmt_list, list) {
 825                 if (!hw_check_valid_format(subs, params, fp))
 826                         continue;
 827
 828                 ep = get_endpoint_in_use(chip, fp->endpoint,
 829                                          subs->data_endpoint);
 830                 if (ep) {
 831                         hwc_debug("rate limit %d for ep#%x\n",
 832                                   ep->cur_rate, fp->endpoint);
 833                         rmin = min(rmin, ep->cur_rate);
 834                         rmax = max(rmax, ep->cur_rate);
 835                         continue;
 836                 }
 837
 838                 if (fp->implicit_fb) {
 839                         ep = get_endpoint_in_use(chip, fp->sync_ep,
 840                                                  subs->sync_endpoint);
 841                         if (ep) {
 842                                 hwc_debug("rate limit %d for sync_ep#%x\n",
 843                                           ep->cur_rate, fp->sync_ep);
 844                                 rmin = min(rmin, ep->cur_rate);
 845                                 rmax = max(rmax, ep->cur_rate);
 846                                 continue;
 847                         }
 848                 }
 849
 850                 r = snd_usb_endpoint_get_clock_rate(chip, fp->clock);
 851                 if (r > 0) {
 852                         if (!snd_interval_test(it, r))
 853                                 continue;
 854                         rmin = min(rmin, r);
 855                         rmax = max(rmax, r);
 856                         continue;
 857                 }
 858                 if (fp->rate_table && fp->nr_rates) {
 859                         for (i = 0; i < fp->nr_rates; i++) {
 860                                 r = fp->rate_table[i];
 861                                 if (!snd_interval_test(it, r))
 862                                         continue;
 863                                 rmin = min(rmin, r);
 864                                 rmax = max(rmax, r);
 865                         }
 866                 } else {
 867                         rmin = min(rmin, fp->rate_min);
 868                         rmax = max(rmax, fp->rate_max);
 869                 }
 870         }
 871
 872         return apply_hw_params_minmax(it, rmin, rmax);
 873 }
 874
 875
 876 static int hw_rule_channels(struct snd_pcm_hw_params *params,
 877                             struct snd_pcm_hw_rule *rule)
 878 {
 879         struct snd_usb_substream *subs = rule->private;
 880         const struct audioformat *fp;
 881         struct snd_interval *it = hw_param_interval(params, SNDRV_PCM_HW_PARAM_CHANNELS);
 882         unsigned int rmin, rmax;
 883
 884         hwc_debug("hw_rule_channels: (%d,%d)\n", it->min, it->max);
 885         rmin = UINT_MAX;
 886         rmax = 0;
 887         list_for_each_entry(fp, &subs->fmt_list, list) {
 888                 if (!hw_check_valid_format(subs, params, fp))
 889                         continue;
 890                 rmin = min(rmin, fp->channels);
 891                 rmax = max(rmax, fp->channels);
 892         }
 893
 894         return apply_hw_params_minmax(it, rmin, rmax);
 895 }
 896
 897 static int apply_hw_params_format_bits(struct snd_mask *fmt, u64 fbits)
 898 {
 899         u32 oldbits[2];
 900         int changed;
 901
 902         oldbits[0] = fmt->bits[0];
 903         oldbits[1] = fmt->bits[1];
 904         fmt->bits[0] &= (u32)fbits;
 905         fmt->bits[1] &= (u32)(fbits >> 32);
 906         if (!fmt->bits[0] && !fmt->bits[1]) {
 907                 hwc_debug("  --> get empty\n");
 908                 return -EINVAL;
 909         }
 910         changed = (oldbits[0] != fmt->bits[0] || oldbits[1] != fmt->bits[1]);
 911         hwc_debug("  --> %x:%x (changed = %d)\n", fmt->bits[0], fmt->bits[1], changed);
 912         return changed;
 913 }
 914
 915 static int hw_rule_format(struct snd_pcm_hw_params *params,
 916                           struct snd_pcm_hw_rule *rule)
 917 {
 918         struct snd_usb_substream *subs = rule->private;
 919         struct snd_usb_audio *chip = subs->stream->chip;
 920         const struct snd_usb_endpoint *ep;
 921         const struct audioformat *fp;
 922         struct snd_mask *fmt = hw_param_mask(params, SNDRV_PCM_HW_PARAM_FORMAT);
 923         u64 fbits;
 924
 925         hwc_debug("hw_rule_format: %x:%x\n", fmt->bits[0], fmt->bits[1]);
 926         fbits = 0;
 927         list_for_each_entry(fp, &subs->fmt_list, list) {
 928                 if (!hw_check_valid_format(subs, params, fp))
 929                         continue;
 930
 931                 ep = get_endpoint_in_use(chip, fp->endpoint,
 932                                          subs->data_endpoint);
 933                 if (ep) {
 934                         hwc_debug("format limit %d for ep#%x\n",
 935                                   ep->cur_format, fp->endpoint);
 936                         fbits |= pcm_format_to_bits(ep->cur_format);
 937                         continue;
 938                 }
 939
 940                 if (fp->implicit_fb) {
 941                         ep = get_endpoint_in_use(chip, fp->sync_ep,
 942                                                  subs->sync_endpoint);
 943                         if (ep) {
 944                                 hwc_debug("format limit %d for sync_ep#%x\n",
 945                                           ep->cur_format, fp->sync_ep);
 946                                 fbits |= pcm_format_to_bits(ep->cur_format);
 947                                 continue;
 948                         }
 949                 }
 950
 951                 fbits |= fp->formats;
 952         }
 953         return apply_hw_params_format_bits(fmt, fbits);
 954 }
 955
 956 static int hw_rule_period_time(struct snd_pcm_hw_params *params,
 957                                struct snd_pcm_hw_rule *rule)
 958 {
 959         struct snd_usb_substream *subs = rule->private;
 960         const struct audioformat *fp;
 961         struct snd_interval *it;
 962         unsigned char min_datainterval;
 963         unsigned int pmin;
 964
 965         it = hw_param_interval(params, SNDRV_PCM_HW_PARAM_PERIOD_TIME);
 966         hwc_debug("hw_rule_period_time: (%u,%u)\n", it->min, it->max);
 967         min_datainterval = 0xff;
 968         list_for_each_entry(fp, &subs->fmt_list, list) {
 969                 if (!hw_check_valid_format(subs, params, fp))
 970                         continue;
 971                 min_datainterval = min(min_datainterval, fp->datainterval);
 972         }
 973         if (min_datainterval == 0xff) {
 974                 hwc_debug("  --> get empty\n");
 975                 it->empty = 1;
 976                 return -EINVAL;
 977         }
 978         pmin = 125 * (1 << min_datainterval);
 979
 980         return apply_hw_params_minmax(it, pmin, UINT_MAX);
 981 }
 982
 983 /* additional hw constraints for implicit feedback mode */
 984 static int hw_rule_period_size_implicit_fb(struct snd_pcm_hw_params *params,
 985                                            struct snd_pcm_hw_rule *rule)
 986 {
 987         struct snd_usb_substream *subs = rule->private;
 988         struct snd_usb_audio *chip = subs->stream->chip;
 989         const struct audioformat *fp;
 990         const struct snd_usb_endpoint *ep;
 991         struct snd_interval *it;
 992         unsigned int rmin, rmax;
 993
 994         it = hw_param_interval(params, SNDRV_PCM_HW_PARAM_PERIOD_SIZE);
 995         hwc_debug("hw_rule_period_size: (%u,%u)\n", it->min, it->max);
 996         rmin = UINT_MAX;
 997         rmax = 0;
 998         list_for_each_entry(fp, &subs->fmt_list, list) {
 999                 if (!hw_check_valid_format(subs, params, fp))
1000                         continue;
1001                 ep = get_endpoint_in_use(chip, fp->endpoint,
1002                                          subs->data_endpoint);
1003                 if (ep) {
1004                         hwc_debug("period size limit %d for ep#%x\n",
1005                                   ep->cur_period_frames, fp->endpoint);
1006                         rmin = min(rmin, ep->cur_period_frames);
1007                         rmax = max(rmax, ep->cur_period_frames);
1008                         continue;
1009                 }
1010
1011                 if (fp->implicit_fb) {
1012                         ep = get_endpoint_in_use(chip, fp->sync_ep,
1013                                                  subs->sync_endpoint);
1014                         if (ep) {
1015                                 hwc_debug("period size limit %d for sync_ep#%x\n",
1016                                           ep->cur_period_frames, fp->sync_ep);
1017                                 rmin = min(rmin, ep->cur_period_frames);
1018                                 rmax = max(rmax, ep->cur_period_frames);
1019                                 continue;
1020                         }
1021                 }
1022         }
1023
1024         if (!rmax)
1025                 return 0; /* no limit by implicit fb */
1026         return apply_hw_params_minmax(it, rmin, rmax);
1027 }
1028
1029 static int hw_rule_periods_implicit_fb(struct snd_pcm_hw_params *params,
1030                                        struct snd_pcm_hw_rule *rule)
1031 {
1032         struct snd_usb_substream *subs = rule->private;
1033         struct snd_usb_audio *chip = subs->stream->chip;
1034         const struct audioformat *fp;
1035         const struct snd_usb_endpoint *ep;
1036         struct snd_interval *it;
1037         unsigned int rmin, rmax;
1038
1039         it = hw_param_interval(params, SNDRV_PCM_HW_PARAM_PERIODS);
1040         hwc_debug("hw_rule_periods: (%u,%u)\n", it->min, it->max);
1041         rmin = UINT_MAX;
1042         rmax = 0;
1043         list_for_each_entry(fp, &subs->fmt_list, list) {
1044                 if (!hw_check_valid_format(subs, params, fp))
1045                         continue;
1046                 ep = get_endpoint_in_use(chip, fp->endpoint,
1047                                          subs->data_endpoint);
1048                 if (ep) {
1049                         hwc_debug("periods limit %d for ep#%x\n",
1050                                   ep->cur_buffer_periods, fp->endpoint);
1051                         rmin = min(rmin, ep->cur_buffer_periods);
1052                         rmax = max(rmax, ep->cur_buffer_periods);
1053                         continue;
1054                 }
1055
1056                 if (fp->implicit_fb) {
1057                         ep = get_endpoint_in_use(chip, fp->sync_ep,
1058                                                  subs->sync_endpoint);
1059                         if (ep) {
1060                                 hwc_debug("periods limit %d for sync_ep#%x\n",
1061                                           ep->cur_buffer_periods, fp->sync_ep);
1062                                 rmin = min(rmin, ep->cur_buffer_periods);
1063                                 rmax = max(rmax, ep->cur_buffer_periods);
1064                                 continue;
1065                         }
1066                 }
1067         }
1068
1069         if (!rmax)
1070                 return 0; /* no limit by implicit fb */
1071         return apply_hw_params_minmax(it, rmin, rmax);
1072 }
1073
1074 /*
1075  * set up the runtime hardware information.
1076  */
1077
1078 static int setup_hw_info(struct snd_pcm_runtime *runtime, struct snd_usb_substream *subs)
1079 {
1080         const struct audioformat *fp;
1081         unsigned int pt, ptmin;
1082         int param_period_time_if_needed = -1;
1083         int err;
1084
1085         runtime->hw.formats = subs->formats;
1086
1087         runtime->hw.rate_min = 0x7fffffff;
1088         runtime->hw.rate_max = 0;
1089         runtime->hw.channels_min = 256;
1090         runtime->hw.channels_max = 0;
1091         runtime->hw.rates = 0;
1092         ptmin = UINT_MAX;
1093         /* check min/max rates and channels */
1094         list_for_each_entry(fp, &subs->fmt_list, list) {
1095                 runtime->hw.rates |= fp->rates;
1096                 if (runtime->hw.rate_min > fp->rate_min)
1097                         runtime->hw.rate_min = fp->rate_min;
1098                 if (runtime->hw.rate_max < fp->rate_max)
1099                         runtime->hw.rate_max = fp->rate_max;
1100                 if (runtime->hw.channels_min > fp->channels)
1101                         runtime->hw.channels_min = fp->channels;
1102                 if (runtime->hw.channels_max < fp->channels)
1103                         runtime->hw.channels_max = fp->channels;
1104                 if (fp->fmt_type == UAC_FORMAT_TYPE_II && fp->frame_size > 0) {
1105                         /* FIXME: there might be more than one audio formats... */
1106                         runtime->hw.period_bytes_min = runtime->hw.period_bytes_max =
1107                                 fp->frame_size;
1108                 }
1109                 pt = 125 * (1 << fp->datainterval);
1110                 ptmin = min(ptmin, pt);
1111         }
1112
1113         param_period_time_if_needed = SNDRV_PCM_HW_PARAM_PERIOD_TIME;
1114         if (subs->speed == USB_SPEED_FULL)
1115                 /* full speed devices have fixed data packet interval */
1116                 ptmin = 1000;
1117         if (ptmin == 1000)
1118                 /* if period time doesn't go below 1 ms, no rules needed */
1119                 param_period_time_if_needed = -1;
1120
1121         err = snd_pcm_hw_constraint_minmax(runtime,
1122                                            SNDRV_PCM_HW_PARAM_PERIOD_TIME,
1123                                            ptmin, UINT_MAX);
1124         if (err < 0)
1125                 return err;
1126
1127         err = snd_pcm_hw_rule_add(runtime, 0, SNDRV_PCM_HW_PARAM_RATE,
1128                                   hw_rule_rate, subs,
1129                                   SNDRV_PCM_HW_PARAM_RATE,
1130                                   SNDRV_PCM_HW_PARAM_FORMAT,
1131                                   SNDRV_PCM_HW_PARAM_CHANNELS,
1132                                   param_period_time_if_needed,
1133                                   -1);
1134         if (err < 0)
1135                 return err;
1136
1137         err = snd_pcm_hw_rule_add(runtime, 0, SNDRV_PCM_HW_PARAM_CHANNELS,
1138                                   hw_rule_channels, subs,
1139                                   SNDRV_PCM_HW_PARAM_CHANNELS,
1140                                   SNDRV_PCM_HW_PARAM_FORMAT,
1141                                   SNDRV_PCM_HW_PARAM_RATE,
1142                                   param_period_time_if_needed,
1143                                   -1);
1144         if (err < 0)
1145                 return err;
1146         err = snd_pcm_hw_rule_add(runtime, 0, SNDRV_PCM_HW_PARAM_FORMAT,
1147                                   hw_rule_format, subs,
1148                                   SNDRV_PCM_HW_PARAM_FORMAT,
1149                                   SNDRV_PCM_HW_PARAM_RATE,
1150                                   SNDRV_PCM_HW_PARAM_CHANNELS,
1151                                   param_period_time_if_needed,
1152                                   -1);
1153         if (err < 0)
1154                 return err;
1155         if (param_period_time_if_needed >= 0) {
1156                 err = snd_pcm_hw_rule_add(runtime, 0,
1157                                           SNDRV_PCM_HW_PARAM_PERIOD_TIME,
1158                                           hw_rule_period_time, subs,
1159                                           SNDRV_PCM_HW_PARAM_FORMAT,
1160                                           SNDRV_PCM_HW_PARAM_CHANNELS,
1161                                           SNDRV_PCM_HW_PARAM_RATE,
1162                                           -1);
1163                 if (err < 0)
1164                         return err;
1165         }
1166
1167         /* set max period and buffer sizes for 1 and 2 seconds, respectively */
1168         err = snd_pcm_hw_constraint_minmax(runtime,
1169                                            SNDRV_PCM_HW_PARAM_PERIOD_TIME,
1170                                            0, 1000000);
1171         if (err < 0)
1172                 return err;
1173         err = snd_pcm_hw_constraint_minmax(runtime,
1174                                            SNDRV_PCM_HW_PARAM_BUFFER_TIME,
1175                                            0, 2000000);
1176         if (err < 0)
1177                 return err;
1178
1179         /* additional hw constraints for implicit fb */
1180         err = snd_pcm_hw_rule_add(runtime, 0, SNDRV_PCM_HW_PARAM_PERIOD_SIZE,
1181                                   hw_rule_period_size_implicit_fb, subs,
1182                                   SNDRV_PCM_HW_PARAM_PERIOD_SIZE, -1);
1183         if (err < 0)
1184                 return err;
1185         err = snd_pcm_hw_rule_add(runtime, 0, SNDRV_PCM_HW_PARAM_PERIODS,
1186                                   hw_rule_periods_implicit_fb, subs,
1187                                   SNDRV_PCM_HW_PARAM_PERIODS, -1);
1188         if (err < 0)
1189                 return err;
1190
1191         list_for_each_entry(fp, &subs->fmt_list, list) {
1192                 if (fp->implicit_fb) {
1193                         runtime->hw.info |= SNDRV_PCM_INFO_JOINT_DUPLEX;
1194                         break;
1195                 }
1196         }
1197
1198         return 0;
1199 }
1200
1201 static int snd_usb_pcm_open(struct snd_pcm_substream *substream)
1202 {
1203         int direction = substream->stream;
1204         struct snd_usb_stream *as = snd_pcm_substream_chip(substream);
1205         struct snd_pcm_runtime *runtime = substream->runtime;
1206         struct snd_usb_substream *subs = &as->substream[direction];
1207         int ret;
1208
1209         runtime->hw = snd_usb_hardware;
1210         /* need an explicit sync to catch applptr update in low-latency mode */
1211         if (direction == SNDRV_PCM_STREAM_PLAYBACK &&
1212             as->chip->lowlatency)
1213                 runtime->hw.info |= SNDRV_PCM_INFO_SYNC_APPLPTR;
1214         runtime->private_data = subs;
1215         subs->pcm_substream = substream;
1216         /* runtime PM is also done there */
1217
1218         /* initialize DSD/DOP context */
1219         subs->dsd_dop.byte_idx = 0;
1220         subs->dsd_dop.channel = 0;
1221         subs->dsd_dop.marker = 1;
1222
1223         ret = setup_hw_info(runtime, subs);
1224         if (ret < 0)
1225                 return ret;
1226         ret = snd_usb_autoresume(subs->stream->chip);
1227         if (ret < 0)
1228                 return ret;
1229         ret = snd_media_stream_init(subs, as->pcm, direction);
1230         if (ret < 0)
1231                 snd_usb_autosuspend(subs->stream->chip);
1232         return ret;
1233 }
1234
1235 static int snd_usb_pcm_close(struct snd_pcm_substream *substream)
1236 {
1237         int direction = substream->stream;
1238         struct snd_usb_stream *as = snd_pcm_substream_chip(substream);
1239         struct snd_usb_substream *subs = &as->substream[direction];
1240         int ret;
1241
1242         snd_media_stop_pipeline(subs);
1243
1244         if (!snd_usb_lock_shutdown(subs->stream->chip)) {
1245                 ret = snd_usb_pcm_change_state(subs, UAC3_PD_STATE_D1);
1246                 snd_usb_unlock_shutdown(subs->stream->chip);
1247                 if (ret < 0)
1248                         return ret;
1249         }
1250
1251         subs->pcm_substream = NULL;
1252         snd_usb_autosuspend(subs->stream->chip);
1253
1254         return 0;
1255 }
1256
1257 /* Since a URB can handle only a single linear buffer, we must use double
1258  * buffering when the data to be transferred overflows the buffer boundary.
1259  * To avoid inconsistencies when updating hwptr_done, we use double buffering
1260  * for all URBs.
1261  */
1262 static void retire_capture_urb(struct snd_usb_substream *subs,
1263                                struct urb *urb)
1264 {
1265         struct snd_pcm_runtime *runtime = subs->pcm_substream->runtime;
1266         unsigned int stride, frames, bytes, oldptr;
1267         int i, period_elapsed = 0;
1268         unsigned long flags;
1269         unsigned char *cp;
1270         int current_frame_number;
1271
1272         /* read frame number here, update pointer in critical section */
1273         current_frame_number = usb_get_current_frame_number(subs->dev);
1274
1275         stride = runtime->frame_bits >> 3;
1276
1277         for (i = 0; i < urb->number_of_packets; i++) {
1278                 cp = (unsigned char *)urb->transfer_buffer + urb->iso_frame_desc[i].offset + subs->pkt_offset_adj;
1279                 if (urb->iso_frame_desc[i].status && printk_ratelimit()) {
1280                         dev_dbg(&subs->dev->dev, "frame %d active: %d\n",
1281                                 i, urb->iso_frame_desc[i].status);
1282                         // continue;
1283                 }
1284                 bytes = urb->iso_frame_desc[i].actual_length;
1285                 if (subs->stream_offset_adj > 0) {
1286                         unsigned int adj = min(subs->stream_offset_adj, bytes);
1287                         cp += adj;
1288                         bytes -= adj;
1289                         subs->stream_offset_adj -= adj;
1290                 }
1291                 frames = bytes / stride;
1292                 if (!subs->txfr_quirk)
1293                         bytes = frames * stride;
1294                 if (bytes % (runtime->sample_bits >> 3) != 0) {
1295                         int oldbytes = bytes;
1296                         bytes = frames * stride;
1297                         dev_warn_ratelimited(&subs->dev->dev,
1298                                  "Corrected urb data len. %d->%d\n",
1299                                                         oldbytes, bytes);
1300                 }
1301                 /* update the current pointer */
1302                 spin_lock_irqsave(&subs->lock, flags);
1303                 oldptr = subs->hwptr_done;
1304                 subs->hwptr_done += bytes;
1305                 if (subs->hwptr_done >= subs->buffer_bytes)
1306                         subs->hwptr_done -= subs->buffer_bytes;
1307                 frames = (bytes + (oldptr % stride)) / stride;
1308                 subs->transfer_done += frames;
1309                 if (subs->transfer_done >= runtime->period_size) {
1310                         subs->transfer_done -= runtime->period_size;
1311                         period_elapsed = 1;
1312                 }
1313
1314                 /* realign last_frame_number */
1315                 subs->last_frame_number = current_frame_number;
1316
1317                 spin_unlock_irqrestore(&subs->lock, flags);
1318                 /* copy a data chunk */
1319                 if (oldptr + bytes > subs->buffer_bytes) {
1320                         unsigned int bytes1 = subs->buffer_bytes - oldptr;
1321
1322                         memcpy(runtime->dma_area + oldptr, cp, bytes1);
1323                         memcpy(runtime->dma_area, cp + bytes1, bytes - bytes1);
1324                 } else {
1325                         memcpy(runtime->dma_area + oldptr, cp, bytes);
1326                 }
1327         }
1328
1329         if (period_elapsed)
1330                 snd_pcm_period_elapsed(subs->pcm_substream);
1331 }
1332
1333 static void urb_ctx_queue_advance(struct snd_usb_substream *subs,
1334                                   struct urb *urb, unsigned int bytes)
1335 {
1336         struct snd_urb_ctx *ctx = urb->context;
1337
1338         ctx->queued += bytes;
1339         subs->inflight_bytes += bytes;
1340         subs->hwptr_done += bytes;
1341         if (subs->hwptr_done >= subs->buffer_bytes)
1342                 subs->hwptr_done -= subs->buffer_bytes;
1343 }
1344
1345 static inline void fill_playback_urb_dsd_dop(struct snd_usb_substream *subs,
1346                                              struct urb *urb, unsigned int bytes)
1347 {
1348         struct snd_pcm_runtime *runtime = subs->pcm_substream->runtime;
1349         unsigned int dst_idx = 0;
1350         unsigned int src_idx = subs->hwptr_done;
1351         unsigned int wrap = subs->buffer_bytes;
1352         u8 *dst = urb->transfer_buffer;
1353         u8 *src = runtime->dma_area;
1354         static const u8 marker[] = { 0x05, 0xfa };
1355         unsigned int queued = 0;
1356
1357         /*
1358          * The DSP DOP format defines a way to transport DSD samples over
1359          * normal PCM data endpoints. It requires stuffing of marker bytes
1360          * (0x05 and 0xfa, alternating per sample frame), and then expects
1361          * 2 additional bytes of actual payload. The whole frame is stored
1362          * LSB.
1363          *
1364          * Hence, for a stereo transport, the buffer layout looks like this,
1365          * where L refers to left channel samples and R to right.
1366          *
1367          *   L1 L2 0x05   R1 R2 0x05   L3 L4 0xfa  R3 R4 0xfa
1368          *   L5 L6 0x05   R5 R6 0x05   L7 L8 0xfa  R7 R8 0xfa
1369          *   .....
1370          *
1371          */
1372
1373         while (bytes--) {
1374                 if (++subs->dsd_dop.byte_idx == 3) {
1375                         /* frame boundary? */
1376                         dst[dst_idx++] = marker[subs->dsd_dop.marker];
1377                         src_idx += 2;
1378                         subs->dsd_dop.byte_idx = 0;
1379
1380                         if (++subs->dsd_dop.channel % runtime->channels == 0) {
1381                                 /* alternate the marker */
1382                                 subs->dsd_dop.marker++;
1383                                 subs->dsd_dop.marker %= ARRAY_SIZE(marker);
1384                                 subs->dsd_dop.channel = 0;
1385                         }
1386                 } else {
1387                         /* stuff the DSD payload */
1388                         int idx = (src_idx + subs->dsd_dop.byte_idx - 1) % wrap;
1389
1390                         if (subs->cur_audiofmt->dsd_bitrev)
1391                                 dst[dst_idx++] = bitrev8(src[idx]);
1392                         else
1393                                 dst[dst_idx++] = src[idx];
1394                         queued++;
1395                 }
1396         }
1397
1398         urb_ctx_queue_advance(subs, urb, queued);
1399 }
1400
1401 /* copy bit-reversed bytes onto transfer buffer */
1402 static void fill_playback_urb_dsd_bitrev(struct snd_usb_substream *subs,
1403                                          struct urb *urb, unsigned int bytes)
1404 {
1405         struct snd_pcm_runtime *runtime = subs->pcm_substream->runtime;
1406         const u8 *src = runtime->dma_area;
1407         u8 *buf = urb->transfer_buffer;
1408         int i, ofs = subs->hwptr_done;
1409
1410         for (i = 0; i < bytes; i++) {
1411                 *buf++ = bitrev8(src[ofs]);
1412                 if (++ofs >= subs->buffer_bytes)
1413                         ofs = 0;
1414         }
1415
1416         urb_ctx_queue_advance(subs, urb, bytes);
1417 }
1418
1419 static void copy_to_urb(struct snd_usb_substream *subs, struct urb *urb,
1420                         int offset, int stride, unsigned int bytes)
1421 {
1422         struct snd_pcm_runtime *runtime = subs->pcm_substream->runtime;
1423
1424         if (subs->hwptr_done + bytes > subs->buffer_bytes) {
1425                 /* err, the transferred area goes over buffer boundary. */
1426                 unsigned int bytes1 = subs->buffer_bytes - subs->hwptr_done;
1427
1428                 memcpy(urb->transfer_buffer + offset,
1429                        runtime->dma_area + subs->hwptr_done, bytes1);
1430                 memcpy(urb->transfer_buffer + offset + bytes1,
1431                        runtime->dma_area, bytes - bytes1);
1432         } else {
1433                 memcpy(urb->transfer_buffer + offset,
1434                        runtime->dma_area + subs->hwptr_done, bytes);
1435         }
1436
1437         urb_ctx_queue_advance(subs, urb, bytes);
1438 }
1439
1440 static unsigned int copy_to_urb_quirk(struct snd_usb_substream *subs,
1441                                       struct urb *urb, int stride,
1442                                       unsigned int bytes)
1443 {
1444         __le32 packet_length;
1445         int i;
1446
1447         /* Put __le32 length descriptor at start of each packet. */
1448         for (i = 0; i < urb->number_of_packets; i++) {
1449                 unsigned int length = urb->iso_frame_desc[i].length;
1450                 unsigned int offset = urb->iso_frame_desc[i].offset;
1451
1452                 packet_length = cpu_to_le32(length);
1453                 offset += i * sizeof(packet_length);
1454                 urb->iso_frame_desc[i].offset = offset;
1455                 urb->iso_frame_desc[i].length += sizeof(packet_length);
1456                 memcpy(urb->transfer_buffer + offset,
1457                        &packet_length, sizeof(packet_length));
1458                 copy_to_urb(subs, urb, offset + sizeof(packet_length),
1459                             stride, length);
1460         }
1461         /* Adjust transfer size accordingly. */
1462         bytes += urb->number_of_packets * sizeof(packet_length);
1463         return bytes;
1464 }
1465
1466 static int prepare_playback_urb(struct snd_usb_substream *subs,
1467                                 struct urb *urb,
1468                                 bool in_stream_lock)
1469 {
1470         struct snd_pcm_runtime *runtime = subs->pcm_substream->runtime;
1471         struct snd_usb_endpoint *ep = subs->data_endpoint;
1472         struct snd_urb_ctx *ctx = urb->context;
1473         unsigned int frames, bytes;
1474         int counts;
1475         unsigned int transfer_done, frame_limit, avail = 0;
1476         int i, stride, period_elapsed = 0;
1477         unsigned long flags;
1478         int err = 0;
1479
1480         stride = ep->stride;
1481
1482         frames = 0;
1483         ctx->queued = 0;
1484         urb->number_of_packets = 0;
1485
1486         spin_lock_irqsave(&subs->lock, flags);
1487         frame_limit = subs->frame_limit + ep->max_urb_frames;
1488         transfer_done = subs->transfer_done;
1489
1490         if (subs->lowlatency_playback &&
1491             runtime->state != SNDRV_PCM_STATE_DRAINING) {
1492                 unsigned int hwptr = subs->hwptr_done / stride;
1493
1494                 /* calculate the byte offset-in-buffer of the appl_ptr */
1495                 avail = (runtime->control->appl_ptr - runtime->hw_ptr_base)
1496                         % runtime->buffer_size;
1497                 if (avail <= hwptr)
1498                         avail += runtime->buffer_size;
1499                 avail -= hwptr;
1500         }
1501
1502         for (i = 0; i < ctx->packets; i++) {
1503                 counts = snd_usb_endpoint_next_packet_size(ep, ctx, i, avail);
1504                 if (counts < 0)
1505                         break;
1506                 /* set up descriptor */
1507                 urb->iso_frame_desc[i].offset = frames * stride;
1508                 urb->iso_frame_desc[i].length = counts * stride;
1509                 frames += counts;
1510                 avail -= counts;
1511                 urb->number_of_packets++;
1512                 transfer_done += counts;
1513                 if (transfer_done >= runtime->period_size) {
1514                         transfer_done -= runtime->period_size;
1515                         frame_limit = 0;
1516                         period_elapsed = 1;
1517                         if (subs->fmt_type == UAC_FORMAT_TYPE_II) {
1518                                 if (transfer_done > 0) {
1519                                         /* FIXME: fill-max mode is not
1520                                          * supported yet */
1521                                         frames -= transfer_done;
1522                                         counts -= transfer_done;
1523                                         urb->iso_frame_desc[i].length =
1524                                                 counts * stride;
1525                                         transfer_done = 0;
1526                                 }
1527                                 i++;
1528                                 if (i < ctx->packets) {
1529                                         /* add a transfer delimiter */
1530                                         urb->iso_frame_desc[i].offset =
1531                                                 frames * stride;
1532                                         urb->iso_frame_desc[i].length = 0;
1533                                         urb->number_of_packets++;
1534                                 }
1535                                 break;
1536                         }
1537                 }
1538                 /* finish at the period boundary or after enough frames */
1539                 if ((period_elapsed || transfer_done >= frame_limit) &&
1540                     !snd_usb_endpoint_implicit_feedback_sink(ep))
1541                         break;
1542         }
1543
1544         if (!frames) {
1545                 err = -EAGAIN;
1546                 goto unlock;
1547         }
1548
1549         bytes = frames * stride;
1550         subs->transfer_done = transfer_done;
1551         subs->frame_limit = frame_limit;
1552         if (unlikely(ep->cur_format == SNDRV_PCM_FORMAT_DSD_U16_LE &&
1553                      subs->cur_audiofmt->dsd_dop)) {
1554                 fill_playback_urb_dsd_dop(subs, urb, bytes);
1555         } else if (unlikely(ep->cur_format == SNDRV_PCM_FORMAT_DSD_U8 &&
1556                            subs->cur_audiofmt->dsd_bitrev)) {
1557                 fill_playback_urb_dsd_bitrev(subs, urb, bytes);
1558         } else {
1559                 /* usual PCM */
1560                 if (!subs->tx_length_quirk)
1561                         copy_to_urb(subs, urb, 0, stride, bytes);
1562                 else
1563                         bytes = copy_to_urb_quirk(subs, urb, stride, bytes);
1564                         /* bytes is now amount of outgoing data */
1565         }
1566
1567         subs->last_frame_number = usb_get_current_frame_number(subs->dev);
1568
1569         if (subs->trigger_tstamp_pending_update) {
1570                 /* this is the first actual URB submitted,
1571                  * update trigger timestamp to reflect actual start time
1572                  */
1573                 snd_pcm_gettime(runtime, &runtime->trigger_tstamp);
1574                 subs->trigger_tstamp_pending_update = false;
1575         }
1576
1577         if (period_elapsed && !subs->running && subs->lowlatency_playback) {
1578                 subs->period_elapsed_pending = 1;
1579                 period_elapsed = 0;
1580         }
1581
1582  unlock:
1583         spin_unlock_irqrestore(&subs->lock, flags);
1584         if (err < 0)
1585                 return err;
1586         urb->transfer_buffer_length = bytes;
1587         if (period_elapsed) {
1588                 if (in_stream_lock)
1589                         snd_pcm_period_elapsed_under_stream_lock(subs->pcm_substream);
1590                 else
1591                         snd_pcm_period_elapsed(subs->pcm_substream);
1592         }
1593         return 0;
1594 }
1595
1596 /*
1597  * process after playback data complete
1598  * - decrease the delay count again
1599  */
1600 static void retire_playback_urb(struct snd_usb_substream *subs,
1601                                struct urb *urb)
1602 {
1603         unsigned long flags;
1604         struct snd_urb_ctx *ctx = urb->context;
1605         bool period_elapsed = false;
1606
1607         spin_lock_irqsave(&subs->lock, flags);
1608         if (ctx->queued) {
1609                 if (subs->inflight_bytes >= ctx->queued)
1610                         subs->inflight_bytes -= ctx->queued;
1611                 else
1612                         subs->inflight_bytes = 0;
1613         }
1614
1615         subs->last_frame_number = usb_get_current_frame_number(subs->dev);
1616         if (subs->running) {
1617                 period_elapsed = subs->period_elapsed_pending;
1618                 subs->period_elapsed_pending = 0;
1619         }
1620         spin_unlock_irqrestore(&subs->lock, flags);
1621         if (period_elapsed)
1622                 snd_pcm_period_elapsed(subs->pcm_substream);
1623 }
1624
1625 /* PCM ack callback for the playback stream;
1626  * this plays a role only when the stream is running in low-latency mode.
1627  */
1628 static int snd_usb_pcm_playback_ack(struct snd_pcm_substream *substream)
1629 {
1630         struct snd_usb_substream *subs = substream->runtime->private_data;
1631         struct snd_usb_endpoint *ep;
1632
1633         if (!subs->lowlatency_playback || !subs->running)
1634                 return 0;
1635         ep = subs->data_endpoint;
1636         if (!ep)
1637                 return 0;
1638         /* When no more in-flight URBs available, try to process the pending
1639          * outputs here
1640          */
1641         if (!ep->active_mask)
1642                 snd_usb_queue_pending_output_urbs(ep, true);
1643         return 0;
1644 }
1645
1646 static int snd_usb_substream_playback_trigger(struct snd_pcm_substream *substream,
1647                                               int cmd)
1648 {
1649         struct snd_usb_substream *subs = substream->runtime->private_data;
1650         int err;
1651
1652         switch (cmd) {
1653         case SNDRV_PCM_TRIGGER_START:
1654                 subs->trigger_tstamp_pending_update = true;
1655                 fallthrough;
1656         case SNDRV_PCM_TRIGGER_PAUSE_RELEASE:
1657                 snd_usb_endpoint_set_callback(subs->data_endpoint,
1658                                               prepare_playback_urb,
1659                                               retire_playback_urb,
1660                                               subs);
1661                 if (subs->lowlatency_playback &&
1662                     cmd == SNDRV_PCM_TRIGGER_START) {
1663                         if (in_free_wheeling_mode(substream->runtime))
1664                                 subs->lowlatency_playback = false;
1665                         err = start_endpoints(subs);
1666                         if (err < 0) {
1667                                 snd_usb_endpoint_set_callback(subs->data_endpoint,
1668                                                               NULL, NULL, NULL);
1669                                 return err;
1670                         }
1671                 }
1672                 subs->running = 1;
1673                 dev_dbg(&subs->dev->dev, "%d:%d Start Playback PCM\n",
1674                         subs->cur_audiofmt->iface,
1675                         subs->cur_audiofmt->altsetting);
1676                 return 0;
1677         case SNDRV_PCM_TRIGGER_SUSPEND:
1678         case SNDRV_PCM_TRIGGER_STOP:
1679                 stop_endpoints(subs, substream->runtime->state == SNDRV_PCM_STATE_DRAINING);
1680                 snd_usb_endpoint_set_callback(subs->data_endpoint,
1681                                               NULL, NULL, NULL);
1682                 subs->running = 0;
1683                 dev_dbg(&subs->dev->dev, "%d:%d Stop Playback PCM\n",
1684                         subs->cur_audiofmt->iface,
1685                         subs->cur_audiofmt->altsetting);
1686                 return 0;
1687         case SNDRV_PCM_TRIGGER_PAUSE_PUSH:
1688                 /* keep retire_data_urb for delay calculation */
1689                 snd_usb_endpoint_set_callback(subs->data_endpoint,
1690                                               NULL,
1691                                               retire_playback_urb,
1692                                               subs);
1693                 subs->running = 0;
1694                 dev_dbg(&subs->dev->dev, "%d:%d Pause Playback PCM\n",
1695                         subs->cur_audiofmt->iface,
1696                         subs->cur_audiofmt->altsetting);
1697                 return 0;
1698         }
1699
1700         return -EINVAL;
1701 }
1702
1703 static int snd_usb_substream_capture_trigger(struct snd_pcm_substream *substream,
1704                                              int cmd)
1705 {
1706         int err;
1707         struct snd_usb_substream *subs = substream->runtime->private_data;
1708
1709         switch (cmd) {
1710         case SNDRV_PCM_TRIGGER_START:
1711                 err = start_endpoints(subs);
1712                 if (err < 0)
1713                         return err;
1714                 fallthrough;
1715         case SNDRV_PCM_TRIGGER_PAUSE_RELEASE:
1716                 snd_usb_endpoint_set_callback(subs->data_endpoint,
1717                                               NULL, retire_capture_urb,
1718                                               subs);
1719                 subs->last_frame_number = usb_get_current_frame_number(subs->dev);
1720                 subs->running = 1;
1721                 dev_dbg(&subs->dev->dev, "%d:%d Start Capture PCM\n",
1722                         subs->cur_audiofmt->iface,
1723                         subs->cur_audiofmt->altsetting);
1724                 return 0;
1725         case SNDRV_PCM_TRIGGER_SUSPEND:
1726         case SNDRV_PCM_TRIGGER_STOP:
1727                 stop_endpoints(subs, false);
1728                 fallthrough;
1729         case SNDRV_PCM_TRIGGER_PAUSE_PUSH:
1730                 snd_usb_endpoint_set_callback(subs->data_endpoint,
1731                                               NULL, NULL, NULL);
1732                 subs->running = 0;
1733                 dev_dbg(&subs->dev->dev, "%d:%d Stop Capture PCM\n",
1734                         subs->cur_audiofmt->iface,
1735                         subs->cur_audiofmt->altsetting);
1736                 return 0;
1737         }
1738
1739         return -EINVAL;
1740 }
1741
1742 static const struct snd_pcm_ops snd_usb_playback_ops = {
1743         .open =         snd_usb_pcm_open,
1744         .close =        snd_usb_pcm_close,
1745         .hw_params =    snd_usb_hw_params,
1746         .hw_free =      snd_usb_hw_free,
1747         .prepare =      snd_usb_pcm_prepare,
1748         .trigger =      snd_usb_substream_playback_trigger,
1749         .sync_stop =    snd_usb_pcm_sync_stop,
1750         .pointer =      snd_usb_pcm_pointer,
1751         .ack =          snd_usb_pcm_playback_ack,
1752 };
1753
1754 static const struct snd_pcm_ops snd_usb_capture_ops = {
1755         .open =         snd_usb_pcm_open,
1756         .close =        snd_usb_pcm_close,
1757         .hw_params =    snd_usb_hw_params,
1758         .hw_free =      snd_usb_hw_free,
1759         .prepare =      snd_usb_pcm_prepare,
1760         .trigger =      snd_usb_substream_capture_trigger,
1761         .sync_stop =    snd_usb_pcm_sync_stop,
1762         .pointer =      snd_usb_pcm_pointer,
1763 };
1764
1765 void snd_usb_set_pcm_ops(struct snd_pcm *pcm, int stream)
1766 {
1767         const struct snd_pcm_ops *ops;
1768
1769         ops = stream == SNDRV_PCM_STREAM_PLAYBACK ?
1770                         &snd_usb_playback_ops : &snd_usb_capture_ops;
1771         snd_pcm_set_ops(pcm, stream, ops);
1772 }
1773
1774 void snd_usb_preallocate_buffer(struct snd_usb_substream *subs)
1775 {
1776         struct snd_pcm *pcm = subs->stream->pcm;
1777         struct snd_pcm_substream *s = pcm->streams[subs->direction].substream;
1778         struct device *dev = subs->dev->bus->sysdev;
1779
1780         if (snd_usb_use_vmalloc)
1781                 snd_pcm_set_managed_buffer(s, SNDRV_DMA_TYPE_VMALLOC,
1782                                            NULL, 0, 0);
1783         else
1784                 snd_pcm_set_managed_buffer(s, SNDRV_DMA_TYPE_DEV_SG,
1785                                            dev, 64*1024, 512*1024);
1786 }