sound/firewire/dice/dice-stream.c

   1 /*
   2  * dice_stream.c - a part of driver for DICE based devices
   3  *
   4  * Copyright (c) Clemens Ladisch <clemens@ladisch.de>
   5  * Copyright (c) 2014 Takashi Sakamoto <o-takashi@sakamocchi.jp>
   6  *
   7  * Licensed under the terms of the GNU General Public License, version 2.
   8  */
   9
  10 #include "dice.h"
  11
  12 #define CALLBACK_TIMEOUT        200
  13 #define NOTIFICATION_TIMEOUT_MS (2 * MSEC_PER_SEC)
  14
  15 struct reg_params {
  16         unsigned int count;
  17         unsigned int size;
  18 };
  19
  20 const unsigned int snd_dice_rates[SND_DICE_RATES_COUNT] = {
  21         /* mode 0 */
  22         [0] =  32000,
  23         [1] =  44100,
  24         [2] =  48000,
  25         /* mode 1 */
  26         [3] =  88200,
  27         [4] =  96000,
  28         /* mode 2 */
  29         [5] = 176400,
  30         [6] = 192000,
  31 };
  32
  33 int snd_dice_stream_get_rate_mode(struct snd_dice *dice, unsigned int rate,
  34                                   enum snd_dice_rate_mode *mode)
  35 {
  36         /* Corresponding to each entry in snd_dice_rates. */
  37         static const enum snd_dice_rate_mode modes[] = {
  38                 [0] = SND_DICE_RATE_MODE_LOW,
  39                 [1] = SND_DICE_RATE_MODE_LOW,
  40                 [2] = SND_DICE_RATE_MODE_LOW,
  41                 [3] = SND_DICE_RATE_MODE_MIDDLE,
  42                 [4] = SND_DICE_RATE_MODE_MIDDLE,
  43                 [5] = SND_DICE_RATE_MODE_HIGH,
  44                 [6] = SND_DICE_RATE_MODE_HIGH,
  45         };
  46         int i;
  47
  48         for (i = 0; i < ARRAY_SIZE(snd_dice_rates); i++) {
  49                 if (!(dice->clock_caps & BIT(i)))
  50                         continue;
  51                 if (snd_dice_rates[i] != rate)
  52                         continue;
  53
  54                 *mode = modes[i];
  55                 return 0;
  56         }
  57
  58         return -EINVAL;
  59 }
  60
  61 /*
  62  * This operation has an effect to synchronize GLOBAL_STATUS/GLOBAL_SAMPLE_RATE
  63  * to GLOBAL_STATUS. Especially, just after powering on, these are different.
  64  */
  65 static int ensure_phase_lock(struct snd_dice *dice, unsigned int rate)
  66 {
  67         __be32 reg, nominal;
  68         u32 data;
  69         int i;
  70         int err;
  71
  72         err = snd_dice_transaction_read_global(dice, GLOBAL_CLOCK_SELECT,
  73                                                &reg, sizeof(reg));
  74         if (err < 0)
  75                 return err;
  76
  77         data = be32_to_cpu(reg);
  78
  79         data &= ~CLOCK_RATE_MASK;
  80         for (i = 0; i < ARRAY_SIZE(snd_dice_rates); ++i) {
  81                 if (snd_dice_rates[i] == rate)
  82                         break;
  83         }
  84         if (i == ARRAY_SIZE(snd_dice_rates))
  85                 return -EINVAL;
  86         data |= i << CLOCK_RATE_SHIFT;
  87
  88         if (completion_done(&dice->clock_accepted))
  89                 reinit_completion(&dice->clock_accepted);
  90
  91         reg = cpu_to_be32(data);
  92         err = snd_dice_transaction_write_global(dice, GLOBAL_CLOCK_SELECT,
  93                                                 &reg, sizeof(reg));
  94         if (err < 0)
  95                 return err;
  96
  97         if (wait_for_completion_timeout(&dice->clock_accepted,
  98                         msecs_to_jiffies(NOTIFICATION_TIMEOUT_MS)) == 0) {
  99                 /*
 100                  * Old versions of Dice firmware transfer no notification when
 101                  * the same clock status as current one is set. In this case,
 102                  * just check current clock status.
 103                  */
 104                 err = snd_dice_transaction_read_global(dice, GLOBAL_STATUS,
 105                                                 &nominal, sizeof(nominal));
 106                 if (err < 0)
 107                         return err;
 108                 if (!(be32_to_cpu(nominal) & STATUS_SOURCE_LOCKED))
 109                         return -ETIMEDOUT;
 110         }
 111
 112         return 0;
 113 }
 114
 115 static int get_register_params(struct snd_dice *dice,
 116                                struct reg_params *tx_params,
 117                                struct reg_params *rx_params)
 118 {
 119         __be32 reg[2];
 120         int err;
 121
 122         err = snd_dice_transaction_read_tx(dice, TX_NUMBER, reg, sizeof(reg));
 123         if (err < 0)
 124                 return err;
 125         tx_params->count =
 126                         min_t(unsigned int, be32_to_cpu(reg[0]), MAX_STREAMS);
 127         tx_params->size = be32_to_cpu(reg[1]) * 4;
 128
 129         err = snd_dice_transaction_read_rx(dice, RX_NUMBER, reg, sizeof(reg));
 130         if (err < 0)
 131                 return err;
 132         rx_params->count =
 133                         min_t(unsigned int, be32_to_cpu(reg[0]), MAX_STREAMS);
 134         rx_params->size = be32_to_cpu(reg[1]) * 4;
 135
 136         return 0;
 137 }
 138
 139 static void release_resources(struct snd_dice *dice)
 140 {
 141         unsigned int i;
 142
 143         for (i = 0; i < MAX_STREAMS; i++) {
 144                 if (amdtp_stream_running(&dice->tx_stream[i])) {
 145                         amdtp_stream_pcm_abort(&dice->tx_stream[i]);
 146                         amdtp_stream_stop(&dice->tx_stream[i]);
 147                 }
 148                 if (amdtp_stream_running(&dice->rx_stream[i])) {
 149                         amdtp_stream_pcm_abort(&dice->rx_stream[i]);
 150                         amdtp_stream_stop(&dice->rx_stream[i]);
 151                 }
 152
 153                 fw_iso_resources_free(&dice->tx_resources[i]);
 154                 fw_iso_resources_free(&dice->rx_resources[i]);
 155         }
 156 }
 157
 158 static void stop_streams(struct snd_dice *dice, enum amdtp_stream_direction dir,
 159                          struct reg_params *params)
 160 {
 161         __be32 reg;
 162         unsigned int i;
 163
 164         for (i = 0; i < params->count; i++) {
 165                 reg = cpu_to_be32((u32)-1);
 166                 if (dir == AMDTP_IN_STREAM) {
 167                         snd_dice_transaction_write_tx(dice,
 168                                         params->size * i + TX_ISOCHRONOUS,
 169                                         &reg, sizeof(reg));
 170                 } else {
 171                         snd_dice_transaction_write_rx(dice,
 172                                         params->size * i + RX_ISOCHRONOUS,
 173                                         &reg, sizeof(reg));
 174                 }
 175         }
 176 }
 177
 178 static int keep_resources(struct snd_dice *dice,
 179                           enum amdtp_stream_direction dir, unsigned int index,
 180                           unsigned int rate, unsigned int pcm_chs,
 181                           unsigned int midi_ports)
 182 {
 183         struct amdtp_stream *stream;
 184         struct fw_iso_resources *resources;
 185         bool double_pcm_frames;
 186         unsigned int i;
 187         int err;
 188
 189         if (dir == AMDTP_IN_STREAM) {
 190                 stream = &dice->tx_stream[index];
 191                 resources = &dice->tx_resources[index];
 192         } else {
 193                 stream = &dice->rx_stream[index];
 194                 resources = &dice->rx_resources[index];
 195         }
 196
 197         /*
 198          * At 176.4/192.0 kHz, Dice has a quirk to transfer two PCM frames in
 199          * one data block of AMDTP packet. Thus sampling transfer frequency is
 200          * a half of PCM sampling frequency, i.e. PCM frames at 192.0 kHz are
 201          * transferred on AMDTP packets at 96 kHz. Two successive samples of a
 202          * channel are stored consecutively in the packet. This quirk is called
 203          * as 'Dual Wire'.
 204          * For this quirk, blocking mode is required and PCM buffer size should
 205          * be aligned to SYT_INTERVAL.
 206          */
 207         double_pcm_frames = rate > 96000;
 208         if (double_pcm_frames) {
 209                 rate /= 2;
 210                 pcm_chs *= 2;
 211         }
 212
 213         err = amdtp_am824_set_parameters(stream, rate, pcm_chs, midi_ports,
 214                                          double_pcm_frames);
 215         if (err < 0)
 216                 return err;
 217
 218         if (double_pcm_frames) {
 219                 pcm_chs /= 2;
 220
 221                 for (i = 0; i < pcm_chs; i++) {
 222                         amdtp_am824_set_pcm_position(stream, i, i * 2);
 223                         amdtp_am824_set_pcm_position(stream, i + pcm_chs,
 224                                                      i * 2 + 1);
 225                 }
 226         }
 227
 228         return fw_iso_resources_allocate(resources,
 229                                 amdtp_stream_get_max_payload(stream),
 230                                 fw_parent_device(dice->unit)->max_speed);
 231 }
 232
 233 static int start_streams(struct snd_dice *dice, enum amdtp_stream_direction dir,
 234                          unsigned int rate, struct reg_params *params)
 235 {
 236         __be32 reg[2];
 237         enum snd_dice_rate_mode mode;
 238         unsigned int i, pcm_chs, midi_ports;
 239         struct amdtp_stream *streams;
 240         struct fw_iso_resources *resources;
 241         struct fw_device *fw_dev = fw_parent_device(dice->unit);
 242         int err = 0;
 243
 244         if (dir == AMDTP_IN_STREAM) {
 245                 streams = dice->tx_stream;
 246                 resources = dice->tx_resources;
 247         } else {
 248                 streams = dice->rx_stream;
 249                 resources = dice->rx_resources;
 250         }
 251
 252         err = snd_dice_stream_get_rate_mode(dice, rate, &mode);
 253         if (err < 0)
 254                 return err;
 255
 256         for (i = 0; i < params->count; i++) {
 257                 unsigned int pcm_cache;
 258                 unsigned int midi_cache;
 259
 260                 if (dir == AMDTP_IN_STREAM) {
 261                         pcm_cache = dice->tx_pcm_chs[i][mode];
 262                         midi_cache = dice->tx_midi_ports[i];
 263                         err = snd_dice_transaction_read_tx(dice,
 264                                         params->size * i + TX_NUMBER_AUDIO,
 265                                         reg, sizeof(reg));
 266                 } else {
 267                         pcm_cache = dice->rx_pcm_chs[i][mode];
 268                         midi_cache = dice->rx_midi_ports[i];
 269                         err = snd_dice_transaction_read_rx(dice,
 270                                         params->size * i + RX_NUMBER_AUDIO,
 271                                         reg, sizeof(reg));
 272                 }
 273                 if (err < 0)
 274                         return err;
 275                 pcm_chs = be32_to_cpu(reg[0]);
 276                 midi_ports = be32_to_cpu(reg[1]);
 277
 278                 /* These are important for developer of this driver. */
 279                 if (pcm_chs != pcm_cache || midi_ports != midi_cache) {
 280                         dev_info(&dice->unit->device,
 281                                  "cache mismatch: pcm: %u:%u, midi: %u:%u\n",
 282                                  pcm_chs, pcm_cache, midi_ports, midi_cache);
 283                         return -EPROTO;
 284                 }
 285
 286                 err = keep_resources(dice, dir, i, rate, pcm_chs, midi_ports);
 287                 if (err < 0)
 288                         return err;
 289
 290                 reg[0] = cpu_to_be32(resources[i].channel);
 291                 if (dir == AMDTP_IN_STREAM) {
 292                         err = snd_dice_transaction_write_tx(dice,
 293                                         params->size * i + TX_ISOCHRONOUS,
 294                                         reg, sizeof(reg[0]));
 295                 } else {
 296                         err = snd_dice_transaction_write_rx(dice,
 297                                         params->size * i + RX_ISOCHRONOUS,
 298                                         reg, sizeof(reg[0]));
 299                 }
 300                 if (err < 0)
 301                         return err;
 302
 303                 if (dir == AMDTP_IN_STREAM) {
 304                         reg[0] = cpu_to_be32(fw_dev->max_speed);
 305                         err = snd_dice_transaction_write_tx(dice,
 306                                         params->size * i + TX_SPEED,
 307                                         reg, sizeof(reg[0]));
 308                         if (err < 0)
 309                                 return err;
 310                 }
 311
 312                 err = amdtp_stream_start(&streams[i], resources[i].channel,
 313                                          fw_dev->max_speed);
 314                 if (err < 0)
 315                         return err;
 316         }
 317
 318         return err;
 319 }
 320
 321 static int start_duplex_streams(struct snd_dice *dice, unsigned int rate)
 322 {
 323         struct reg_params tx_params, rx_params;
 324         int i;
 325         int err;
 326
 327         err = get_register_params(dice, &tx_params, &rx_params);
 328         if (err < 0)
 329                 return err;
 330
 331         /* Stop transmission. */
 332         stop_streams(dice, AMDTP_IN_STREAM, &tx_params);
 333         stop_streams(dice, AMDTP_OUT_STREAM, &rx_params);
 334         snd_dice_transaction_clear_enable(dice);
 335         release_resources(dice);
 336
 337         err = ensure_phase_lock(dice, rate);
 338         if (err < 0) {
 339                 dev_err(&dice->unit->device, "fail to ensure phase lock\n");
 340                 return err;
 341         }
 342
 343         /* Likely to have changed stream formats. */
 344         err = get_register_params(dice, &tx_params, &rx_params);
 345         if (err < 0)
 346                 return err;
 347
 348         /* Start both streams. */
 349         err = start_streams(dice, AMDTP_IN_STREAM, rate, &tx_params);
 350         if (err < 0)
 351                 goto error;
 352         err = start_streams(dice, AMDTP_OUT_STREAM, rate, &rx_params);
 353         if (err < 0)
 354                 goto error;
 355
 356         err = snd_dice_transaction_set_enable(dice);
 357         if (err < 0) {
 358                 dev_err(&dice->unit->device, "fail to enable interface\n");
 359                 goto error;
 360         }
 361
 362         for (i = 0; i < MAX_STREAMS; i++) {
 363                 if ((i < tx_params.count &&
 364                     !amdtp_stream_wait_callback(&dice->tx_stream[i],
 365                                                 CALLBACK_TIMEOUT)) ||
 366                     (i < rx_params.count &&
 367                      !amdtp_stream_wait_callback(&dice->rx_stream[i],
 368                                                  CALLBACK_TIMEOUT))) {
 369                         err = -ETIMEDOUT;
 370                         goto error;
 371                 }
 372         }
 373
 374         return 0;
 375 error:
 376         stop_streams(dice, AMDTP_IN_STREAM, &tx_params);
 377         stop_streams(dice, AMDTP_OUT_STREAM, &rx_params);
 378         snd_dice_transaction_clear_enable(dice);
 379         release_resources(dice);
 380         return err;
 381 }
 382
 383 /*
 384  * MEMO: After this function, there're two states of streams:
 385  *  - None streams are running.
 386  *  - All streams are running.
 387  */
 388 int snd_dice_stream_start_duplex(struct snd_dice *dice, unsigned int rate)
 389 {
 390         unsigned int curr_rate;
 391         unsigned int i;
 392         enum snd_dice_rate_mode mode;
 393         int err;
 394
 395         if (dice->substreams_counter == 0)
 396                 return -EIO;
 397
 398         /* Check sampling transmission frequency. */
 399         err = snd_dice_transaction_get_rate(dice, &curr_rate);
 400         if (err < 0) {
 401                 dev_err(&dice->unit->device,
 402                         "fail to get sampling rate\n");
 403                 return err;
 404         }
 405         if (rate == 0)
 406                 rate = curr_rate;
 407         if (rate != curr_rate)
 408                 goto restart;
 409
 410         /* Check error of packet streaming. */
 411         for (i = 0; i < MAX_STREAMS; ++i) {
 412                 if (amdtp_streaming_error(&dice->tx_stream[i]))
 413                         break;
 414                 if (amdtp_streaming_error(&dice->rx_stream[i]))
 415                         break;
 416         }
 417         if (i < MAX_STREAMS)
 418                 goto restart;
 419
 420         /* Check required streams are running or not. */
 421         err = snd_dice_stream_get_rate_mode(dice, rate, &mode);
 422         if (err < 0)
 423                 return err;
 424         for (i = 0; i < MAX_STREAMS; ++i) {
 425                 if (dice->tx_pcm_chs[i][mode] > 0 &&
 426                     !amdtp_stream_running(&dice->tx_stream[i]))
 427                         break;
 428                 if (dice->rx_pcm_chs[i][mode] > 0 &&
 429                     !amdtp_stream_running(&dice->rx_stream[i]))
 430                         break;
 431         }
 432         if (i < MAX_STREAMS)
 433                 goto restart;
 434
 435         return 0;
 436 restart:
 437         return start_duplex_streams(dice, rate);
 438 }
 439
 440 /*
 441  * MEMO: After this function, there're two states of streams:
 442  *  - None streams are running.
 443  *  - All streams are running.
 444  */
 445 void snd_dice_stream_stop_duplex(struct snd_dice *dice)
 446 {
 447         struct reg_params tx_params, rx_params;
 448
 449         if (dice->substreams_counter > 0)
 450                 return;
 451
 452         snd_dice_transaction_clear_enable(dice);
 453
 454         if (get_register_params(dice, &tx_params, &rx_params) == 0) {
 455                 stop_streams(dice, AMDTP_IN_STREAM, &tx_params);
 456                 stop_streams(dice, AMDTP_OUT_STREAM, &rx_params);
 457         }
 458
 459         release_resources(dice);
 460 }
 461
 462 static int init_stream(struct snd_dice *dice, enum amdtp_stream_direction dir,
 463                        unsigned int index)
 464 {
 465         struct amdtp_stream *stream;
 466         struct fw_iso_resources *resources;
 467         int err;
 468
 469         if (dir == AMDTP_IN_STREAM) {
 470                 stream = &dice->tx_stream[index];
 471                 resources = &dice->tx_resources[index];
 472         } else {
 473                 stream = &dice->rx_stream[index];
 474                 resources = &dice->rx_resources[index];
 475         }
 476
 477         err = fw_iso_resources_init(resources, dice->unit);
 478         if (err < 0)
 479                 goto end;
 480         resources->channels_mask = 0x00000000ffffffffuLL;
 481
 482         err = amdtp_am824_init(stream, dice->unit, dir, CIP_BLOCKING);
 483         if (err < 0) {
 484                 amdtp_stream_destroy(stream);
 485                 fw_iso_resources_destroy(resources);
 486         }
 487 end:
 488         return err;
 489 }
 490
 491 /*
 492  * This function should be called before starting streams or after stopping
 493  * streams.
 494  */
 495 static void destroy_stream(struct snd_dice *dice,
 496                            enum amdtp_stream_direction dir,
 497                            unsigned int index)
 498 {
 499         struct amdtp_stream *stream;
 500         struct fw_iso_resources *resources;
 501
 502         if (dir == AMDTP_IN_STREAM) {
 503                 stream = &dice->tx_stream[index];
 504                 resources = &dice->tx_resources[index];
 505         } else {
 506                 stream = &dice->rx_stream[index];
 507                 resources = &dice->rx_resources[index];
 508         }
 509
 510         amdtp_stream_destroy(stream);
 511         fw_iso_resources_destroy(resources);
 512 }
 513
 514 int snd_dice_stream_init_duplex(struct snd_dice *dice)
 515 {
 516         int i, err;
 517
 518         for (i = 0; i < MAX_STREAMS; i++) {
 519                 err = init_stream(dice, AMDTP_IN_STREAM, i);
 520                 if (err < 0) {
 521                         for (; i >= 0; i--)
 522                                 destroy_stream(dice, AMDTP_IN_STREAM, i);
 523                         goto end;
 524                 }
 525         }
 526
 527         for (i = 0; i < MAX_STREAMS; i++) {
 528                 err = init_stream(dice, AMDTP_OUT_STREAM, i);
 529                 if (err < 0) {
 530                         for (; i >= 0; i--)
 531                                 destroy_stream(dice, AMDTP_OUT_STREAM, i);
 532                         for (i = 0; i < MAX_STREAMS; i++)
 533                                 destroy_stream(dice, AMDTP_IN_STREAM, i);
 534                         break;
 535                 }
 536         }
 537 end:
 538         return err;
 539 }
 540
 541 void snd_dice_stream_destroy_duplex(struct snd_dice *dice)
 542 {
 543         unsigned int i;
 544
 545         for (i = 0; i < MAX_STREAMS; i++) {
 546                 destroy_stream(dice, AMDTP_IN_STREAM, i);
 547                 destroy_stream(dice, AMDTP_OUT_STREAM, i);
 548         }
 549 }
 550
 551 void snd_dice_stream_update_duplex(struct snd_dice *dice)
 552 {
 553         struct reg_params tx_params, rx_params;
 554
 555         /*
 556          * On a bus reset, the DICE firmware disables streaming and then goes
 557          * off contemplating its own navel for hundreds of milliseconds before
 558          * it can react to any of our attempts to reenable streaming.  This
 559          * means that we lose synchronization anyway, so we force our streams
 560          * to stop so that the application can restart them in an orderly
 561          * manner.
 562          */
 563         dice->global_enabled = false;
 564
 565         if (get_register_params(dice, &tx_params, &rx_params) == 0) {
 566                 stop_streams(dice, AMDTP_IN_STREAM, &tx_params);
 567                 stop_streams(dice, AMDTP_OUT_STREAM, &rx_params);
 568         }
 569 }
 570
 571 int snd_dice_stream_detect_current_formats(struct snd_dice *dice)
 572 {
 573         unsigned int rate;
 574         enum snd_dice_rate_mode mode;
 575         __be32 reg[2];
 576         struct reg_params tx_params, rx_params;
 577         int i;
 578         int err;
 579
 580         /* If extended protocol is available, detect detail spec. */
 581         err = snd_dice_detect_extension_formats(dice);
 582         if (err >= 0)
 583                 return err;
 584
 585         /*
 586          * Available stream format is restricted at current mode of sampling
 587          * clock.
 588          */
 589         err = snd_dice_transaction_get_rate(dice, &rate);
 590         if (err < 0)
 591                 return err;
 592
 593         err = snd_dice_stream_get_rate_mode(dice, rate, &mode);
 594         if (err < 0)
 595                 return err;
 596
 597         /*
 598          * Just after owning the unit (GLOBAL_OWNER), the unit can return
 599          * invalid stream formats. Selecting clock parameters have an effect
 600          * for the unit to refine it.
 601          */
 602         err = ensure_phase_lock(dice, rate);
 603         if (err < 0)
 604                 return err;
 605
 606         err = get_register_params(dice, &tx_params, &rx_params);
 607         if (err < 0)
 608                 return err;
 609
 610         for (i = 0; i < tx_params.count; ++i) {
 611                 err = snd_dice_transaction_read_tx(dice,
 612                                 tx_params.size * i + TX_NUMBER_AUDIO,
 613                                 reg, sizeof(reg));
 614                 if (err < 0)
 615                         return err;
 616                 dice->tx_pcm_chs[i][mode] = be32_to_cpu(reg[0]);
 617                 dice->tx_midi_ports[i] = max_t(unsigned int,
 618                                 be32_to_cpu(reg[1]), dice->tx_midi_ports[i]);
 619         }
 620         for (i = 0; i < rx_params.count; ++i) {
 621                 err = snd_dice_transaction_read_rx(dice,
 622                                 rx_params.size * i + RX_NUMBER_AUDIO,
 623                                 reg, sizeof(reg));
 624                 if (err < 0)
 625                         return err;
 626                 dice->rx_pcm_chs[i][mode] = be32_to_cpu(reg[0]);
 627                 dice->rx_midi_ports[i] = max_t(unsigned int,
 628                                 be32_to_cpu(reg[1]), dice->rx_midi_ports[i]);
 629         }
 630
 631         return 0;
 632 }
 633
 634 static void dice_lock_changed(struct snd_dice *dice)
 635 {
 636         dice->dev_lock_changed = true;
 637         wake_up(&dice->hwdep_wait);
 638 }
 639
 640 int snd_dice_stream_lock_try(struct snd_dice *dice)
 641 {
 642         int err;
 643
 644         spin_lock_irq(&dice->lock);
 645
 646         if (dice->dev_lock_count < 0) {
 647                 err = -EBUSY;
 648                 goto out;
 649         }
 650
 651         if (dice->dev_lock_count++ == 0)
 652                 dice_lock_changed(dice);
 653         err = 0;
 654 out:
 655         spin_unlock_irq(&dice->lock);
 656         return err;
 657 }
 658
 659 void snd_dice_stream_lock_release(struct snd_dice *dice)
 660 {
 661         spin_lock_irq(&dice->lock);
 662
 663         if (WARN_ON(dice->dev_lock_count <= 0))
 664                 goto out;
 665
 666         if (--dice->dev_lock_count == 0)
 667                 dice_lock_changed(dice);
 668 out:
 669         spin_unlock_irq(&dice->lock);
 670 }