1 /* 2 * oxfw_stream.c - a part of driver for OXFW970/971 based devices 3 * 4 * Copyright (c) 2014 Takashi Sakamoto 5 * 6 * Licensed under the terms of the GNU General Public License, version 2. 7 */ 8 9 #include "oxfw.h" 10 #include <linux/delay.h> 11 12 #define AVC_GENERIC_FRAME_MAXIMUM_BYTES 512 13 #define CALLBACK_TIMEOUT 200 14 15 /* 16 * According to datasheet of Oxford Semiconductor: 17 * OXFW970: 32.0/44.1/48.0/96.0 Khz, 8 audio channels I/O 18 * OXFW971: 32.0/44.1/48.0/88.2/96.0/192.0 kHz, 16 audio channels I/O, MIDI I/O 19 */ 20 static const unsigned int oxfw_rate_table[] = { 21 [0] = 32000, 22 [1] = 44100, 23 [2] = 48000, 24 [3] = 88200, 25 [4] = 96000, 26 [5] = 192000, 27 }; 28 29 /* 30 * See Table 5.7 – Sampling frequency for Multi-bit Audio 31 * in AV/C Stream Format Information Specification 1.1 (Apr 2005, 1394TA) 32 */ 33 static const unsigned int avc_stream_rate_table[] = { 34 [0] = 0x02, 35 [1] = 0x03, 36 [2] = 0x04, 37 [3] = 0x0a, 38 [4] = 0x05, 39 [5] = 0x07, 40 }; 41 42 static int set_rate(struct snd_oxfw *oxfw, unsigned int rate) 43 { 44 int err; 45 46 err = avc_general_set_sig_fmt(oxfw->unit, rate, 47 AVC_GENERAL_PLUG_DIR_IN, 0); 48 if (err < 0) 49 goto end; 50 51 if (oxfw->has_output) 52 err = avc_general_set_sig_fmt(oxfw->unit, rate, 53 AVC_GENERAL_PLUG_DIR_OUT, 0); 54 end: 55 return err; 56 } 57 58 static int set_stream_format(struct snd_oxfw *oxfw, struct amdtp_stream *s, 59 unsigned int rate, unsigned int pcm_channels) 60 { 61 u8 **formats; 62 struct snd_oxfw_stream_formation formation; 63 enum avc_general_plug_dir dir; 64 unsigned int len; 65 int i, err; 66 67 if (s == &oxfw->tx_stream) { 68 formats = oxfw->tx_stream_formats; 69 dir = AVC_GENERAL_PLUG_DIR_OUT; 70 } else { 71 formats = oxfw->rx_stream_formats; 72 dir = AVC_GENERAL_PLUG_DIR_IN; 73 } 74 75 /* Seek stream format for requirements. */ 76 for (i = 0; i < SND_OXFW_STREAM_FORMAT_ENTRIES; i++) { 77 err = snd_oxfw_stream_parse_format(formats[i], &formation); 78 if (err < 0) 79 return err; 80 81 if ((formation.rate == rate) && (formation.pcm == pcm_channels)) 82 break; 83 } 84 if (i == SND_OXFW_STREAM_FORMAT_ENTRIES) 85 return -EINVAL; 86 87 /* If assumed, just change rate. */ 88 if (oxfw->assumed) 89 return set_rate(oxfw, rate); 90 91 /* Calculate format length. */ 92 len = 5 + formats[i][4] * 2; 93 94 err = avc_stream_set_format(oxfw->unit, dir, 0, formats[i], len); 95 if (err < 0) 96 return err; 97 98 /* Some requests just after changing format causes freezing. */ 99 msleep(100); 100 101 return 0; 102 } 103 104 static int start_stream(struct snd_oxfw *oxfw, struct amdtp_stream *stream) 105 { 106 u8 **formats; 107 enum avc_general_plug_dir dir; 108 struct cmp_connection *conn; 109 struct snd_oxfw_stream_formation formation; 110 int i; 111 int err; 112 113 if (stream == &oxfw->rx_stream) { 114 dir = AVC_GENERAL_PLUG_DIR_IN; 115 formats = oxfw->rx_stream_formats; 116 conn = &oxfw->in_conn; 117 } else { 118 dir = AVC_GENERAL_PLUG_DIR_OUT; 119 formats = oxfw->tx_stream_formats; 120 conn = &oxfw->out_conn; 121 } 122 123 err = snd_oxfw_stream_get_current_formation(oxfw, dir, &formation); 124 if (err < 0) 125 return err; 126 127 for (i = 0; i < SND_OXFW_STREAM_FORMAT_ENTRIES; i++) { 128 struct snd_oxfw_stream_formation fmt; 129 130 if (formats[i] == NULL) 131 break; 132 133 err = snd_oxfw_stream_parse_format(formats[i], &fmt); 134 if (err < 0) 135 return err; 136 if (fmt.rate == formation.rate && fmt.pcm == formation.pcm && 137 fmt.midi == formation.midi) 138 break; 139 } 140 if (i == SND_OXFW_STREAM_FORMAT_ENTRIES) 141 return -EINVAL; 142 143 // The stream should have one pcm channels at least. 144 if (formation.pcm == 0) 145 return -EINVAL; 146 147 err = amdtp_am824_set_parameters(stream, formation.rate, formation.pcm, 148 formation.midi * 8, false); 149 if (err < 0) 150 return err; 151 152 err = cmp_connection_establish(conn, 153 amdtp_stream_get_max_payload(stream)); 154 if (err < 0) 155 return err; 156 157 err = amdtp_stream_start(stream, conn->resources.channel, conn->speed); 158 if (err < 0) { 159 cmp_connection_break(conn); 160 return err; 161 } 162 163 // Wait first packet. 164 if (!amdtp_stream_wait_callback(stream, CALLBACK_TIMEOUT)) { 165 amdtp_stream_stop(stream); 166 cmp_connection_break(conn); 167 return -ETIMEDOUT; 168 } 169 170 return 0; 171 } 172 173 static int check_connection_used_by_others(struct snd_oxfw *oxfw, 174 struct amdtp_stream *stream) 175 { 176 struct cmp_connection *conn; 177 bool used; 178 int err; 179 180 if (stream == &oxfw->tx_stream) 181 conn = &oxfw->out_conn; 182 else 183 conn = &oxfw->in_conn; 184 185 err = cmp_connection_check_used(conn, &used); 186 if ((err >= 0) && used && !amdtp_stream_running(stream)) { 187 dev_err(&oxfw->unit->device, 188 "Connection established by others: %cPCR[%d]\n", 189 (conn->direction == CMP_OUTPUT) ? 'o' : 'i', 190 conn->pcr_index); 191 err = -EBUSY; 192 } 193 194 return err; 195 } 196 197 static int init_stream(struct snd_oxfw *oxfw, struct amdtp_stream *stream) 198 { 199 struct cmp_connection *conn; 200 enum cmp_direction c_dir; 201 enum amdtp_stream_direction s_dir; 202 int err; 203 204 if (stream == &oxfw->tx_stream) { 205 conn = &oxfw->out_conn; 206 c_dir = CMP_OUTPUT; 207 s_dir = AMDTP_IN_STREAM; 208 } else { 209 conn = &oxfw->in_conn; 210 c_dir = CMP_INPUT; 211 s_dir = AMDTP_OUT_STREAM; 212 } 213 214 err = cmp_connection_init(conn, oxfw->unit, c_dir, 0); 215 if (err < 0) 216 return err; 217 218 err = amdtp_am824_init(stream, oxfw->unit, s_dir, CIP_NONBLOCKING); 219 if (err < 0) { 220 cmp_connection_destroy(conn); 221 return err; 222 } 223 224 /* 225 * OXFW starts to transmit packets with non-zero dbc. 226 * OXFW postpone transferring packets till handling any asynchronous 227 * packets. As a result, next isochronous packet includes more data 228 * blocks than IEC 61883-6 defines. 229 */ 230 if (stream == &oxfw->tx_stream) { 231 oxfw->tx_stream.flags |= CIP_JUMBO_PAYLOAD; 232 if (oxfw->wrong_dbs) 233 oxfw->tx_stream.flags |= CIP_WRONG_DBS; 234 } 235 236 return 0; 237 } 238 239 int snd_oxfw_stream_reserve_duplex(struct snd_oxfw *oxfw, 240 struct amdtp_stream *stream, 241 unsigned int rate, unsigned int pcm_channels) 242 { 243 struct snd_oxfw_stream_formation formation; 244 enum avc_general_plug_dir dir; 245 int err; 246 247 // Considering JACK/FFADO streaming: 248 // TODO: This can be removed hwdep functionality becomes popular. 249 err = check_connection_used_by_others(oxfw, &oxfw->rx_stream); 250 if (err < 0) 251 return err; 252 if (oxfw->has_output) { 253 err = check_connection_used_by_others(oxfw, &oxfw->tx_stream); 254 if (err < 0) 255 return err; 256 } 257 258 if (stream == &oxfw->tx_stream) 259 dir = AVC_GENERAL_PLUG_DIR_OUT; 260 else 261 dir = AVC_GENERAL_PLUG_DIR_IN; 262 263 err = snd_oxfw_stream_get_current_formation(oxfw, dir, &formation); 264 if (err < 0) 265 return err; 266 if (rate == 0) { 267 rate = formation.rate; 268 pcm_channels = formation.pcm; 269 } 270 if (formation.rate != rate || formation.pcm != pcm_channels) { 271 amdtp_stream_stop(&oxfw->rx_stream); 272 cmp_connection_break(&oxfw->in_conn); 273 274 if (oxfw->has_output) { 275 amdtp_stream_stop(&oxfw->tx_stream); 276 cmp_connection_break(&oxfw->out_conn); 277 } 278 } 279 280 if (oxfw->substreams_count == 0 || 281 formation.rate != rate || formation.pcm != pcm_channels) { 282 err = set_stream_format(oxfw, stream, rate, pcm_channels); 283 if (err < 0) { 284 dev_err(&oxfw->unit->device, 285 "fail to set stream format: %d\n", err); 286 return err; 287 } 288 } 289 290 return 0; 291 } 292 293 int snd_oxfw_stream_start_duplex(struct snd_oxfw *oxfw) 294 { 295 int err; 296 297 if (oxfw->substreams_count == 0) 298 return -EIO; 299 300 if (amdtp_streaming_error(&oxfw->rx_stream) || 301 amdtp_streaming_error(&oxfw->tx_stream)) { 302 amdtp_stream_stop(&oxfw->rx_stream); 303 cmp_connection_break(&oxfw->in_conn); 304 305 if (oxfw->has_output) { 306 amdtp_stream_stop(&oxfw->tx_stream); 307 cmp_connection_break(&oxfw->out_conn); 308 } 309 } 310 311 if (!amdtp_stream_running(&oxfw->rx_stream)) { 312 err = start_stream(oxfw, &oxfw->rx_stream); 313 if (err < 0) { 314 dev_err(&oxfw->unit->device, 315 "fail to start rx stream: %d\n", err); 316 goto error; 317 } 318 } 319 320 if (oxfw->has_output) { 321 if (!amdtp_stream_running(&oxfw->tx_stream)) { 322 err = start_stream(oxfw, &oxfw->tx_stream); 323 if (err < 0) { 324 dev_err(&oxfw->unit->device, 325 "fail to start tx stream: %d\n", err); 326 goto error; 327 } 328 } 329 } 330 331 return 0; 332 error: 333 amdtp_stream_stop(&oxfw->rx_stream); 334 cmp_connection_break(&oxfw->in_conn); 335 if (oxfw->has_output) { 336 amdtp_stream_stop(&oxfw->tx_stream); 337 cmp_connection_break(&oxfw->out_conn); 338 } 339 return err; 340 } 341 342 void snd_oxfw_stream_stop_duplex(struct snd_oxfw *oxfw) 343 { 344 if (oxfw->substreams_count == 0) { 345 amdtp_stream_stop(&oxfw->rx_stream); 346 cmp_connection_break(&oxfw->in_conn); 347 348 if (oxfw->has_output) { 349 amdtp_stream_stop(&oxfw->tx_stream); 350 cmp_connection_break(&oxfw->out_conn); 351 } 352 } 353 } 354 355 static void destroy_stream(struct snd_oxfw *oxfw, struct amdtp_stream *stream) 356 { 357 struct cmp_connection *conn; 358 359 if (stream == &oxfw->tx_stream) 360 conn = &oxfw->out_conn; 361 else 362 conn = &oxfw->in_conn; 363 364 amdtp_stream_destroy(stream); 365 cmp_connection_destroy(conn); 366 } 367 368 int snd_oxfw_stream_init_duplex(struct snd_oxfw *oxfw) 369 { 370 int err; 371 372 err = init_stream(oxfw, &oxfw->rx_stream); 373 if (err < 0) 374 return err; 375 376 if (oxfw->has_output) { 377 err = init_stream(oxfw, &oxfw->tx_stream); 378 if (err < 0) { 379 destroy_stream(oxfw, &oxfw->rx_stream); 380 return err; 381 } 382 } 383 384 return 0; 385 } 386 387 // This function should be called before starting the stream or after stopping 388 // the streams. 389 void snd_oxfw_stream_destroy_duplex(struct snd_oxfw *oxfw) 390 { 391 destroy_stream(oxfw, &oxfw->rx_stream); 392 393 if (oxfw->has_output) 394 destroy_stream(oxfw, &oxfw->tx_stream); 395 } 396 397 void snd_oxfw_stream_update_duplex(struct snd_oxfw *oxfw) 398 { 399 amdtp_stream_stop(&oxfw->rx_stream); 400 cmp_connection_break(&oxfw->in_conn); 401 402 amdtp_stream_pcm_abort(&oxfw->rx_stream); 403 404 if (oxfw->has_output) { 405 amdtp_stream_stop(&oxfw->tx_stream); 406 cmp_connection_break(&oxfw->out_conn); 407 408 amdtp_stream_pcm_abort(&oxfw->tx_stream); 409 } 410 } 411 412 int snd_oxfw_stream_get_current_formation(struct snd_oxfw *oxfw, 413 enum avc_general_plug_dir dir, 414 struct snd_oxfw_stream_formation *formation) 415 { 416 u8 *format; 417 unsigned int len; 418 int err; 419 420 len = AVC_GENERIC_FRAME_MAXIMUM_BYTES; 421 format = kmalloc(len, GFP_KERNEL); 422 if (format == NULL) 423 return -ENOMEM; 424 425 err = avc_stream_get_format_single(oxfw->unit, dir, 0, format, &len); 426 if (err < 0) 427 goto end; 428 if (len < 3) { 429 err = -EIO; 430 goto end; 431 } 432 433 err = snd_oxfw_stream_parse_format(format, formation); 434 end: 435 kfree(format); 436 return err; 437 } 438 439 /* 440 * See Table 6.16 - AM824 Stream Format 441 * Figure 6.19 - format_information field for AM824 Compound 442 * in AV/C Stream Format Information Specification 1.1 (Apr 2005, 1394TA) 443 * Also 'Clause 12 AM824 sequence adaption layers' in IEC 61883-6:2005 444 */ 445 int snd_oxfw_stream_parse_format(u8 *format, 446 struct snd_oxfw_stream_formation *formation) 447 { 448 unsigned int i, e, channels, type; 449 450 memset(formation, 0, sizeof(struct snd_oxfw_stream_formation)); 451 452 /* 453 * this module can support a hierarchy combination that: 454 * Root: Audio and Music (0x90) 455 * Level 1: AM824 Compound (0x40) 456 */ 457 if ((format[0] != 0x90) || (format[1] != 0x40)) 458 return -ENOSYS; 459 460 /* check the sampling rate */ 461 for (i = 0; i < ARRAY_SIZE(avc_stream_rate_table); i++) { 462 if (format[2] == avc_stream_rate_table[i]) 463 break; 464 } 465 if (i == ARRAY_SIZE(avc_stream_rate_table)) 466 return -ENOSYS; 467 468 formation->rate = oxfw_rate_table[i]; 469 470 for (e = 0; e < format[4]; e++) { 471 channels = format[5 + e * 2]; 472 type = format[6 + e * 2]; 473 474 switch (type) { 475 /* IEC 60958 Conformant, currently handled as MBLA */ 476 case 0x00: 477 /* Multi Bit Linear Audio (Raw) */ 478 case 0x06: 479 formation->pcm += channels; 480 break; 481 /* MIDI Conformant */ 482 case 0x0d: 483 formation->midi = channels; 484 break; 485 /* IEC 61937-3 to 7 */ 486 case 0x01: 487 case 0x02: 488 case 0x03: 489 case 0x04: 490 case 0x05: 491 /* Multi Bit Linear Audio */ 492 case 0x07: /* DVD-Audio */ 493 case 0x0c: /* High Precision */ 494 /* One Bit Audio */ 495 case 0x08: /* (Plain) Raw */ 496 case 0x09: /* (Plain) SACD */ 497 case 0x0a: /* (Encoded) Raw */ 498 case 0x0b: /* (Encoded) SACD */ 499 /* SMPTE Time-Code conformant */ 500 case 0x0e: 501 /* Sample Count */ 502 case 0x0f: 503 /* Anciliary Data */ 504 case 0x10: 505 /* Synchronization Stream (Stereo Raw audio) */ 506 case 0x40: 507 /* Don't care */ 508 case 0xff: 509 default: 510 return -ENOSYS; /* not supported */ 511 } 512 } 513 514 if (formation->pcm > AM824_MAX_CHANNELS_FOR_PCM || 515 formation->midi > AM824_MAX_CHANNELS_FOR_MIDI) 516 return -ENOSYS; 517 518 return 0; 519 } 520 521 static int 522 assume_stream_formats(struct snd_oxfw *oxfw, enum avc_general_plug_dir dir, 523 unsigned int pid, u8 *buf, unsigned int *len, 524 u8 **formats) 525 { 526 struct snd_oxfw_stream_formation formation; 527 unsigned int i, eid; 528 int err; 529 530 /* get format at current sampling rate */ 531 err = avc_stream_get_format_single(oxfw->unit, dir, pid, buf, len); 532 if (err < 0) { 533 dev_err(&oxfw->unit->device, 534 "fail to get current stream format for isoc %s plug %d:%d\n", 535 (dir == AVC_GENERAL_PLUG_DIR_IN) ? "in" : "out", 536 pid, err); 537 goto end; 538 } 539 540 /* parse and set stream format */ 541 eid = 0; 542 err = snd_oxfw_stream_parse_format(buf, &formation); 543 if (err < 0) 544 goto end; 545 546 formats[eid] = devm_kmemdup(&oxfw->card->card_dev, buf, *len, 547 GFP_KERNEL); 548 if (!formats[eid]) { 549 err = -ENOMEM; 550 goto end; 551 } 552 553 /* apply the format for each available sampling rate */ 554 for (i = 0; i < ARRAY_SIZE(oxfw_rate_table); i++) { 555 if (formation.rate == oxfw_rate_table[i]) 556 continue; 557 558 err = avc_general_inquiry_sig_fmt(oxfw->unit, 559 oxfw_rate_table[i], 560 dir, pid); 561 if (err < 0) 562 continue; 563 564 eid++; 565 formats[eid] = devm_kmemdup(&oxfw->card->card_dev, buf, *len, 566 GFP_KERNEL); 567 if (formats[eid] == NULL) { 568 err = -ENOMEM; 569 goto end; 570 } 571 formats[eid][2] = avc_stream_rate_table[i]; 572 } 573 574 err = 0; 575 oxfw->assumed = true; 576 end: 577 return err; 578 } 579 580 static int fill_stream_formats(struct snd_oxfw *oxfw, 581 enum avc_general_plug_dir dir, 582 unsigned short pid) 583 { 584 u8 *buf, **formats; 585 unsigned int len, eid = 0; 586 struct snd_oxfw_stream_formation dummy; 587 int err; 588 589 buf = kmalloc(AVC_GENERIC_FRAME_MAXIMUM_BYTES, GFP_KERNEL); 590 if (buf == NULL) 591 return -ENOMEM; 592 593 if (dir == AVC_GENERAL_PLUG_DIR_OUT) 594 formats = oxfw->tx_stream_formats; 595 else 596 formats = oxfw->rx_stream_formats; 597 598 /* get first entry */ 599 len = AVC_GENERIC_FRAME_MAXIMUM_BYTES; 600 err = avc_stream_get_format_list(oxfw->unit, dir, 0, buf, &len, 0); 601 if (err == -ENOSYS) { 602 /* LIST subfunction is not implemented */ 603 len = AVC_GENERIC_FRAME_MAXIMUM_BYTES; 604 err = assume_stream_formats(oxfw, dir, pid, buf, &len, 605 formats); 606 goto end; 607 } else if (err < 0) { 608 dev_err(&oxfw->unit->device, 609 "fail to get stream format %d for isoc %s plug %d:%d\n", 610 eid, (dir == AVC_GENERAL_PLUG_DIR_IN) ? "in" : "out", 611 pid, err); 612 goto end; 613 } 614 615 /* LIST subfunction is implemented */ 616 while (eid < SND_OXFW_STREAM_FORMAT_ENTRIES) { 617 /* The format is too short. */ 618 if (len < 3) { 619 err = -EIO; 620 break; 621 } 622 623 /* parse and set stream format */ 624 err = snd_oxfw_stream_parse_format(buf, &dummy); 625 if (err < 0) 626 break; 627 628 formats[eid] = devm_kmemdup(&oxfw->card->card_dev, buf, len, 629 GFP_KERNEL); 630 if (!formats[eid]) { 631 err = -ENOMEM; 632 break; 633 } 634 635 /* get next entry */ 636 len = AVC_GENERIC_FRAME_MAXIMUM_BYTES; 637 err = avc_stream_get_format_list(oxfw->unit, dir, 0, 638 buf, &len, ++eid); 639 /* No entries remained. */ 640 if (err == -EINVAL) { 641 err = 0; 642 break; 643 } else if (err < 0) { 644 dev_err(&oxfw->unit->device, 645 "fail to get stream format %d for isoc %s plug %d:%d\n", 646 eid, (dir == AVC_GENERAL_PLUG_DIR_IN) ? "in" : 647 "out", 648 pid, err); 649 break; 650 } 651 } 652 end: 653 kfree(buf); 654 return err; 655 } 656 657 int snd_oxfw_stream_discover(struct snd_oxfw *oxfw) 658 { 659 u8 plugs[AVC_PLUG_INFO_BUF_BYTES]; 660 struct snd_oxfw_stream_formation formation; 661 u8 *format; 662 unsigned int i; 663 int err; 664 665 /* the number of plugs for isoc in/out, ext in/out */ 666 err = avc_general_get_plug_info(oxfw->unit, 0x1f, 0x07, 0x00, plugs); 667 if (err < 0) { 668 dev_err(&oxfw->unit->device, 669 "fail to get info for isoc/external in/out plugs: %d\n", 670 err); 671 goto end; 672 } else if ((plugs[0] == 0) && (plugs[1] == 0)) { 673 err = -ENOSYS; 674 goto end; 675 } 676 677 /* use oPCR[0] if exists */ 678 if (plugs[1] > 0) { 679 err = fill_stream_formats(oxfw, AVC_GENERAL_PLUG_DIR_OUT, 0); 680 if (err < 0) 681 goto end; 682 683 for (i = 0; i < SND_OXFW_STREAM_FORMAT_ENTRIES; i++) { 684 format = oxfw->tx_stream_formats[i]; 685 if (format == NULL) 686 continue; 687 err = snd_oxfw_stream_parse_format(format, &formation); 688 if (err < 0) 689 continue; 690 691 /* Add one MIDI port. */ 692 if (formation.midi > 0) 693 oxfw->midi_input_ports = 1; 694 } 695 696 oxfw->has_output = true; 697 } 698 699 /* use iPCR[0] if exists */ 700 if (plugs[0] > 0) { 701 err = fill_stream_formats(oxfw, AVC_GENERAL_PLUG_DIR_IN, 0); 702 if (err < 0) 703 goto end; 704 705 for (i = 0; i < SND_OXFW_STREAM_FORMAT_ENTRIES; i++) { 706 format = oxfw->rx_stream_formats[i]; 707 if (format == NULL) 708 continue; 709 err = snd_oxfw_stream_parse_format(format, &formation); 710 if (err < 0) 711 continue; 712 713 /* Add one MIDI port. */ 714 if (formation.midi > 0) 715 oxfw->midi_output_ports = 1; 716 } 717 } 718 end: 719 return err; 720 } 721 722 void snd_oxfw_stream_lock_changed(struct snd_oxfw *oxfw) 723 { 724 oxfw->dev_lock_changed = true; 725 wake_up(&oxfw->hwdep_wait); 726 } 727 728 int snd_oxfw_stream_lock_try(struct snd_oxfw *oxfw) 729 { 730 int err; 731 732 spin_lock_irq(&oxfw->lock); 733 734 /* user land lock this */ 735 if (oxfw->dev_lock_count < 0) { 736 err = -EBUSY; 737 goto end; 738 } 739 740 /* this is the first time */ 741 if (oxfw->dev_lock_count++ == 0) 742 snd_oxfw_stream_lock_changed(oxfw); 743 err = 0; 744 end: 745 spin_unlock_irq(&oxfw->lock); 746 return err; 747 } 748 749 void snd_oxfw_stream_lock_release(struct snd_oxfw *oxfw) 750 { 751 spin_lock_irq(&oxfw->lock); 752 753 if (WARN_ON(oxfw->dev_lock_count <= 0)) 754 goto end; 755 if (--oxfw->dev_lock_count == 0) 756 snd_oxfw_stream_lock_changed(oxfw); 757 end: 758 spin_unlock_irq(&oxfw->lock); 759 } 760