1 /* pcm.c 2 ** 3 ** Copyright 2011, The Android Open Source Project 4 ** 5 ** Redistribution and use in source and binary forms, with or without 6 ** modification, are permitted provided that the following conditions are met: 7 ** * Redistributions of source code must retain the above copyright 8 ** notice, this list of conditions and the following disclaimer. 9 ** * Redistributions in binary form must reproduce the above copyright 10 ** notice, this list of conditions and the following disclaimer in the 11 ** documentation and/or other materials provided with the distribution. 12 ** * Neither the name of The Android Open Source Project nor the names of 13 ** its contributors may be used to endorse or promote products derived 14 ** from this software without specific prior written permission. 15 ** 16 ** THIS SOFTWARE IS PROVIDED BY The Android Open Source Project ``AS IS'' AND 17 ** ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 18 ** IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 19 ** ARE DISCLAIMED. IN NO EVENT SHALL The Android Open Source Project BE LIABLE 20 ** FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 21 ** DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR 22 ** SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER 23 ** CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 24 ** LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 25 ** OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH 26 ** DAMAGE. 27 */ 28 29 #include <stdio.h> 30 #include <stdlib.h> 31 #include <fcntl.h> 32 #include <stdarg.h> 33 #include <string.h> 34 #include <errno.h> 35 #include <unistd.h> 36 #include <poll.h> 37 38 #include <sys/ioctl.h> 39 #include <sys/mman.h> 40 #include <sys/time.h> 41 #include <limits.h> 42 43 #include <linux/ioctl.h> 44 #define __force 45 #define __bitwise 46 #define __user 47 #include <sound/asound.h> 48 49 #include <tinyalsa/asoundlib.h> 50 51 #define PARAM_MAX SNDRV_PCM_HW_PARAM_LAST_INTERVAL 52 53 /* Logs information into a string; follows snprintf() in that 54 * offset may be greater than size, and though no characters are copied 55 * into string, characters are still counted into offset. */ 56 #define STRLOG(string, offset, size, ...) \ 57 do { int temp, clipoffset = offset > size ? size : offset; \ 58 temp = snprintf(string + clipoffset, size - clipoffset, __VA_ARGS__); \ 59 if (temp > 0) offset += temp; } while (0) 60 61 #ifndef ARRAY_SIZE 62 #define ARRAY_SIZE(a) (sizeof(a) / sizeof((a)[0])) 63 #endif 64 65 /* refer to SNDRV_PCM_ACCESS_##index in sound/asound.h. */ 66 static const char * const access_lookup[] = { 67 "MMAP_INTERLEAVED", 68 "MMAP_NONINTERLEAVED", 69 "MMAP_COMPLEX", 70 "RW_INTERLEAVED", 71 "RW_NONINTERLEAVED", 72 }; 73 74 /* refer to SNDRV_PCM_FORMAT_##index in sound/asound.h. */ 75 static const char * const format_lookup[] = { 76 /*[0] =*/ "S8", 77 "U8", 78 "S16_LE", 79 "S16_BE", 80 "U16_LE", 81 "U16_BE", 82 "S24_LE", 83 "S24_BE", 84 "U24_LE", 85 "U24_BE", 86 "S32_LE", 87 "S32_BE", 88 "U32_LE", 89 "U32_BE", 90 "FLOAT_LE", 91 "FLOAT_BE", 92 "FLOAT64_LE", 93 "FLOAT64_BE", 94 "IEC958_SUBFRAME_LE", 95 "IEC958_SUBFRAME_BE", 96 "MU_LAW", 97 "A_LAW", 98 "IMA_ADPCM", 99 "MPEG", 100 /*[24] =*/ "GSM", 101 /* gap */ 102 [31] = "SPECIAL", 103 "S24_3LE", 104 "S24_3BE", 105 "U24_3LE", 106 "U24_3BE", 107 "S20_3LE", 108 "S20_3BE", 109 "U20_3LE", 110 "U20_3BE", 111 "S18_3LE", 112 "S18_3BE", 113 "U18_3LE", 114 /*[43] =*/ "U18_3BE", 115 #if 0 116 /* recent additions, may not be present on local asound.h */ 117 "G723_24", 118 "G723_24_1B", 119 "G723_40", 120 "G723_40_1B", 121 "DSD_U8", 122 "DSD_U16_LE", 123 #endif 124 }; 125 126 /* refer to SNDRV_PCM_SUBFORMAT_##index in sound/asound.h. */ 127 static const char * const subformat_lookup[] = { 128 "STD", 129 }; 130 131 static inline int param_is_mask(int p) 132 { 133 return (p >= SNDRV_PCM_HW_PARAM_FIRST_MASK) && 134 (p <= SNDRV_PCM_HW_PARAM_LAST_MASK); 135 } 136 137 static inline int param_is_interval(int p) 138 { 139 return (p >= SNDRV_PCM_HW_PARAM_FIRST_INTERVAL) && 140 (p <= SNDRV_PCM_HW_PARAM_LAST_INTERVAL); 141 } 142 143 static inline struct snd_interval *param_to_interval(struct snd_pcm_hw_params *p, int n) 144 { 145 return &(p->intervals[n - SNDRV_PCM_HW_PARAM_FIRST_INTERVAL]); 146 } 147 148 static inline struct snd_mask *param_to_mask(struct snd_pcm_hw_params *p, int n) 149 { 150 return &(p->masks[n - SNDRV_PCM_HW_PARAM_FIRST_MASK]); 151 } 152 153 static void param_set_mask(struct snd_pcm_hw_params *p, int n, unsigned int bit) 154 { 155 if (bit >= SNDRV_MASK_MAX) 156 return; 157 if (param_is_mask(n)) { 158 struct snd_mask *m = param_to_mask(p, n); 159 m->bits[0] = 0; 160 m->bits[1] = 0; 161 m->bits[bit >> 5] |= (1 << (bit & 31)); 162 } 163 } 164 165 static void param_set_min(struct snd_pcm_hw_params *p, int n, unsigned int val) 166 { 167 if (param_is_interval(n)) { 168 struct snd_interval *i = param_to_interval(p, n); 169 i->min = val; 170 } 171 } 172 173 static unsigned int param_get_min(struct snd_pcm_hw_params *p, int n) 174 { 175 if (param_is_interval(n)) { 176 struct snd_interval *i = param_to_interval(p, n); 177 return i->min; 178 } 179 return 0; 180 } 181 182 static void param_set_max(struct snd_pcm_hw_params *p, int n, unsigned int val) 183 { 184 if (param_is_interval(n)) { 185 struct snd_interval *i = param_to_interval(p, n); 186 i->max = val; 187 } 188 } 189 190 static unsigned int param_get_max(struct snd_pcm_hw_params *p, int n) 191 { 192 if (param_is_interval(n)) { 193 struct snd_interval *i = param_to_interval(p, n); 194 return i->max; 195 } 196 return 0; 197 } 198 199 static void param_set_int(struct snd_pcm_hw_params *p, int n, unsigned int val) 200 { 201 if (param_is_interval(n)) { 202 struct snd_interval *i = param_to_interval(p, n); 203 i->min = val; 204 i->max = val; 205 i->integer = 1; 206 } 207 } 208 209 static unsigned int param_get_int(struct snd_pcm_hw_params *p, int n) 210 { 211 if (param_is_interval(n)) { 212 struct snd_interval *i = param_to_interval(p, n); 213 if (i->integer) 214 return i->max; 215 } 216 return 0; 217 } 218 219 static void param_init(struct snd_pcm_hw_params *p) 220 { 221 int n; 222 223 memset(p, 0, sizeof(*p)); 224 for (n = SNDRV_PCM_HW_PARAM_FIRST_MASK; 225 n <= SNDRV_PCM_HW_PARAM_LAST_MASK; n++) { 226 struct snd_mask *m = param_to_mask(p, n); 227 m->bits[0] = ~0; 228 m->bits[1] = ~0; 229 } 230 for (n = SNDRV_PCM_HW_PARAM_FIRST_INTERVAL; 231 n <= SNDRV_PCM_HW_PARAM_LAST_INTERVAL; n++) { 232 struct snd_interval *i = param_to_interval(p, n); 233 i->min = 0; 234 i->max = ~0; 235 } 236 p->rmask = ~0U; 237 p->cmask = 0; 238 p->info = ~0U; 239 } 240 241 #define PCM_ERROR_MAX 128 242 243 struct pcm { 244 int fd; 245 unsigned int flags; 246 int running:1; 247 int prepared:1; 248 int underruns; 249 unsigned int buffer_size; 250 unsigned int boundary; 251 char error[PCM_ERROR_MAX]; 252 struct pcm_config config; 253 struct snd_pcm_mmap_status *mmap_status; 254 struct snd_pcm_mmap_control *mmap_control; 255 struct snd_pcm_sync_ptr *sync_ptr; 256 void *mmap_buffer; 257 unsigned int noirq_frames_per_msec; 258 int wait_for_avail_min; 259 unsigned int subdevice; 260 }; 261 262 unsigned int pcm_get_buffer_size(struct pcm *pcm) 263 { 264 return pcm->buffer_size; 265 } 266 267 const char* pcm_get_error(struct pcm *pcm) 268 { 269 return pcm->error; 270 } 271 272 unsigned int pcm_get_subdevice(struct pcm *pcm) 273 { 274 return pcm->subdevice; 275 } 276 277 static int oops(struct pcm *pcm, int e, const char *fmt, ...) 278 { 279 va_list ap; 280 int sz; 281 282 va_start(ap, fmt); 283 vsnprintf(pcm->error, PCM_ERROR_MAX, fmt, ap); 284 va_end(ap); 285 sz = strlen(pcm->error); 286 287 if (errno) 288 snprintf(pcm->error + sz, PCM_ERROR_MAX - sz, 289 ": %s", strerror(e)); 290 return -1; 291 } 292 293 static unsigned int pcm_format_to_alsa(enum pcm_format format) 294 { 295 switch (format) { 296 case PCM_FORMAT_S32_LE: 297 return SNDRV_PCM_FORMAT_S32_LE; 298 case PCM_FORMAT_S8: 299 return SNDRV_PCM_FORMAT_S8; 300 case PCM_FORMAT_S24_3LE: 301 return SNDRV_PCM_FORMAT_S24_3LE; 302 case PCM_FORMAT_S24_LE: 303 return SNDRV_PCM_FORMAT_S24_LE; 304 default: 305 case PCM_FORMAT_S16_LE: 306 return SNDRV_PCM_FORMAT_S16_LE; 307 }; 308 } 309 310 unsigned int pcm_format_to_bits(enum pcm_format format) 311 { 312 switch (format) { 313 case PCM_FORMAT_S32_LE: 314 case PCM_FORMAT_S24_LE: 315 return 32; 316 case PCM_FORMAT_S24_3LE: 317 return 24; 318 default: 319 case PCM_FORMAT_S16_LE: 320 return 16; 321 }; 322 } 323 324 unsigned int pcm_bytes_to_frames(struct pcm *pcm, unsigned int bytes) 325 { 326 return bytes / (pcm->config.channels * 327 (pcm_format_to_bits(pcm->config.format) >> 3)); 328 } 329 330 unsigned int pcm_frames_to_bytes(struct pcm *pcm, unsigned int frames) 331 { 332 return frames * pcm->config.channels * 333 (pcm_format_to_bits(pcm->config.format) >> 3); 334 } 335 336 static int pcm_sync_ptr(struct pcm *pcm, int flags) { 337 if (pcm->sync_ptr) { 338 pcm->sync_ptr->flags = flags; 339 if (ioctl(pcm->fd, SNDRV_PCM_IOCTL_SYNC_PTR, pcm->sync_ptr) < 0) 340 return -1; 341 } 342 return 0; 343 } 344 345 static int pcm_hw_mmap_status(struct pcm *pcm) { 346 347 if (pcm->sync_ptr) 348 return 0; 349 350 int page_size = sysconf(_SC_PAGE_SIZE); 351 pcm->mmap_status = mmap(NULL, page_size, PROT_READ, MAP_FILE | MAP_SHARED, 352 pcm->fd, SNDRV_PCM_MMAP_OFFSET_STATUS); 353 if (pcm->mmap_status == MAP_FAILED) 354 pcm->mmap_status = NULL; 355 if (!pcm->mmap_status) 356 goto mmap_error; 357 358 pcm->mmap_control = mmap(NULL, page_size, PROT_READ | PROT_WRITE, 359 MAP_FILE | MAP_SHARED, pcm->fd, SNDRV_PCM_MMAP_OFFSET_CONTROL); 360 if (pcm->mmap_control == MAP_FAILED) 361 pcm->mmap_control = NULL; 362 if (!pcm->mmap_control) { 363 munmap(pcm->mmap_status, page_size); 364 pcm->mmap_status = NULL; 365 goto mmap_error; 366 } 367 if (pcm->flags & PCM_MMAP) 368 pcm->mmap_control->avail_min = pcm->config.avail_min; 369 else 370 pcm->mmap_control->avail_min = 1; 371 372 return 0; 373 374 mmap_error: 375 376 pcm->sync_ptr = calloc(1, sizeof(*pcm->sync_ptr)); 377 if (!pcm->sync_ptr) 378 return -ENOMEM; 379 pcm->mmap_status = &pcm->sync_ptr->s.status; 380 pcm->mmap_control = &pcm->sync_ptr->c.control; 381 if (pcm->flags & PCM_MMAP) 382 pcm->mmap_control->avail_min = pcm->config.avail_min; 383 else 384 pcm->mmap_control->avail_min = 1; 385 386 pcm_sync_ptr(pcm, 0); 387 388 return 0; 389 } 390 391 static void pcm_hw_munmap_status(struct pcm *pcm) { 392 if (pcm->sync_ptr) { 393 free(pcm->sync_ptr); 394 pcm->sync_ptr = NULL; 395 } else { 396 int page_size = sysconf(_SC_PAGE_SIZE); 397 if (pcm->mmap_status) 398 munmap(pcm->mmap_status, page_size); 399 if (pcm->mmap_control) 400 munmap(pcm->mmap_control, page_size); 401 } 402 pcm->mmap_status = NULL; 403 pcm->mmap_control = NULL; 404 } 405 406 static int pcm_areas_copy(struct pcm *pcm, unsigned int pcm_offset, 407 char *buf, unsigned int src_offset, 408 unsigned int frames) 409 { 410 int size_bytes = pcm_frames_to_bytes(pcm, frames); 411 int pcm_offset_bytes = pcm_frames_to_bytes(pcm, pcm_offset); 412 int src_offset_bytes = pcm_frames_to_bytes(pcm, src_offset); 413 414 /* interleaved only atm */ 415 if (pcm->flags & PCM_IN) 416 memcpy(buf + src_offset_bytes, 417 (char*)pcm->mmap_buffer + pcm_offset_bytes, 418 size_bytes); 419 else 420 memcpy((char*)pcm->mmap_buffer + pcm_offset_bytes, 421 buf + src_offset_bytes, 422 size_bytes); 423 return 0; 424 } 425 426 static int pcm_mmap_transfer_areas(struct pcm *pcm, char *buf, 427 unsigned int offset, unsigned int size) 428 { 429 void *pcm_areas; 430 int commit; 431 unsigned int pcm_offset, frames, count = 0; 432 433 while (size > 0) { 434 frames = size; 435 pcm_mmap_begin(pcm, &pcm_areas, &pcm_offset, &frames); 436 pcm_areas_copy(pcm, pcm_offset, buf, offset, frames); 437 commit = pcm_mmap_commit(pcm, pcm_offset, frames); 438 if (commit < 0) { 439 oops(pcm, commit, "failed to commit %d frames\n", frames); 440 return commit; 441 } 442 443 offset += commit; 444 count += commit; 445 size -= commit; 446 } 447 return count; 448 } 449 450 int pcm_get_htimestamp(struct pcm *pcm, unsigned int *avail, 451 struct timespec *tstamp) 452 { 453 int frames; 454 int rc; 455 snd_pcm_uframes_t hw_ptr; 456 457 if (!pcm_is_ready(pcm)) 458 return -1; 459 460 rc = pcm_sync_ptr(pcm, SNDRV_PCM_SYNC_PTR_APPL|SNDRV_PCM_SYNC_PTR_HWSYNC); 461 if (rc < 0) 462 return -1; 463 464 if ((pcm->mmap_status->state != PCM_STATE_RUNNING) && 465 (pcm->mmap_status->state != PCM_STATE_DRAINING)) 466 return -1; 467 468 *tstamp = pcm->mmap_status->tstamp; 469 if (tstamp->tv_sec == 0 && tstamp->tv_nsec == 0) 470 return -1; 471 472 hw_ptr = pcm->mmap_status->hw_ptr; 473 if (pcm->flags & PCM_IN) 474 frames = hw_ptr - pcm->mmap_control->appl_ptr; 475 else 476 frames = hw_ptr + pcm->buffer_size - pcm->mmap_control->appl_ptr; 477 478 if (frames < 0) 479 frames += pcm->boundary; 480 else if (frames > (int)pcm->boundary) 481 frames -= pcm->boundary; 482 483 *avail = (unsigned int)frames; 484 485 return 0; 486 } 487 488 int pcm_mmap_get_hw_ptr(struct pcm* pcm, unsigned int *hw_ptr, struct timespec *tstamp) 489 { 490 int frames; 491 int rc; 492 493 if (pcm == NULL || hw_ptr == NULL || tstamp == NULL) 494 return oops(pcm, EINVAL, "pcm %p, hw_ptr %p, tstamp %p", pcm, hw_ptr, tstamp); 495 496 if (!pcm_is_ready(pcm)) 497 return oops(pcm, errno, "pcm_is_ready failed"); 498 499 rc = pcm_sync_ptr(pcm, SNDRV_PCM_SYNC_PTR_HWSYNC); 500 if (rc < 0) 501 return oops(pcm, errno, "pcm_sync_ptr failed"); 502 503 if ((pcm->mmap_status->state != PCM_STATE_RUNNING) && 504 (pcm->mmap_status->state != PCM_STATE_DRAINING)) 505 return oops(pcm, ENOSYS, "invalid stream state %d", pcm->mmap_status->state); 506 507 *tstamp = pcm->mmap_status->tstamp; 508 if (tstamp->tv_sec == 0 && tstamp->tv_nsec == 0) 509 return oops(pcm, errno, "invalid time stamp"); 510 511 *hw_ptr = pcm->mmap_status->hw_ptr; 512 513 return 0; 514 } 515 516 int pcm_write(struct pcm *pcm, const void *data, unsigned int count) 517 { 518 struct snd_xferi x; 519 520 if (pcm->flags & PCM_IN) 521 return -EINVAL; 522 523 x.buf = (void*)data; 524 x.frames = count / (pcm->config.channels * 525 pcm_format_to_bits(pcm->config.format) / 8); 526 527 for (;;) { 528 if (!pcm->running) { 529 int prepare_error = pcm_prepare(pcm); 530 if (prepare_error) 531 return prepare_error; 532 if (ioctl(pcm->fd, SNDRV_PCM_IOCTL_WRITEI_FRAMES, &x)) 533 return oops(pcm, errno, "cannot write initial data"); 534 pcm->running = 1; 535 return 0; 536 } 537 if (ioctl(pcm->fd, SNDRV_PCM_IOCTL_WRITEI_FRAMES, &x)) { 538 pcm->prepared = 0; 539 pcm->running = 0; 540 if (errno == EPIPE) { 541 /* we failed to make our window -- try to restart if we are 542 * allowed to do so. Otherwise, simply allow the EPIPE error to 543 * propagate up to the app level */ 544 pcm->underruns++; 545 if (pcm->flags & PCM_NORESTART) 546 return -EPIPE; 547 continue; 548 } 549 return oops(pcm, errno, "cannot write stream data"); 550 } 551 return 0; 552 } 553 } 554 555 int pcm_read(struct pcm *pcm, void *data, unsigned int count) 556 { 557 struct snd_xferi x; 558 559 if (!(pcm->flags & PCM_IN)) 560 return -EINVAL; 561 562 x.buf = data; 563 x.frames = count / (pcm->config.channels * 564 pcm_format_to_bits(pcm->config.format) / 8); 565 566 for (;;) { 567 if (!pcm->running) { 568 if (pcm_start(pcm) < 0) { 569 fprintf(stderr, "start error"); 570 return -errno; 571 } 572 } 573 if (ioctl(pcm->fd, SNDRV_PCM_IOCTL_READI_FRAMES, &x)) { 574 pcm->prepared = 0; 575 pcm->running = 0; 576 if (errno == EPIPE) { 577 /* we failed to make our window -- try to restart */ 578 pcm->underruns++; 579 continue; 580 } 581 return oops(pcm, errno, "cannot read stream data"); 582 } 583 return 0; 584 } 585 } 586 587 static struct pcm bad_pcm = { 588 .fd = -1, 589 }; 590 591 struct pcm_params *pcm_params_get(unsigned int card, unsigned int device, 592 unsigned int flags) 593 { 594 struct snd_pcm_hw_params *params; 595 char fn[256]; 596 int fd; 597 598 snprintf(fn, sizeof(fn), "/dev/snd/pcmC%uD%u%c", card, device, 599 flags & PCM_IN ? 'c' : 'p'); 600 601 fd = open(fn, O_RDWR); 602 if (fd < 0) { 603 fprintf(stderr, "cannot open device '%s'\n", fn); 604 goto err_open; 605 } 606 607 params = calloc(1, sizeof(struct snd_pcm_hw_params)); 608 if (!params) 609 goto err_calloc; 610 611 param_init(params); 612 if (ioctl(fd, SNDRV_PCM_IOCTL_HW_REFINE, params)) { 613 fprintf(stderr, "SNDRV_PCM_IOCTL_HW_REFINE error (%d)\n", errno); 614 goto err_hw_refine; 615 } 616 617 close(fd); 618 619 return (struct pcm_params *)params; 620 621 err_hw_refine: 622 free(params); 623 err_calloc: 624 close(fd); 625 err_open: 626 return NULL; 627 } 628 629 void pcm_params_free(struct pcm_params *pcm_params) 630 { 631 struct snd_pcm_hw_params *params = (struct snd_pcm_hw_params *)pcm_params; 632 633 if (params) 634 free(params); 635 } 636 637 static int pcm_param_to_alsa(enum pcm_param param) 638 { 639 switch (param) { 640 case PCM_PARAM_ACCESS: 641 return SNDRV_PCM_HW_PARAM_ACCESS; 642 case PCM_PARAM_FORMAT: 643 return SNDRV_PCM_HW_PARAM_FORMAT; 644 case PCM_PARAM_SUBFORMAT: 645 return SNDRV_PCM_HW_PARAM_SUBFORMAT; 646 case PCM_PARAM_SAMPLE_BITS: 647 return SNDRV_PCM_HW_PARAM_SAMPLE_BITS; 648 break; 649 case PCM_PARAM_FRAME_BITS: 650 return SNDRV_PCM_HW_PARAM_FRAME_BITS; 651 break; 652 case PCM_PARAM_CHANNELS: 653 return SNDRV_PCM_HW_PARAM_CHANNELS; 654 break; 655 case PCM_PARAM_RATE: 656 return SNDRV_PCM_HW_PARAM_RATE; 657 break; 658 case PCM_PARAM_PERIOD_TIME: 659 return SNDRV_PCM_HW_PARAM_PERIOD_TIME; 660 break; 661 case PCM_PARAM_PERIOD_SIZE: 662 return SNDRV_PCM_HW_PARAM_PERIOD_SIZE; 663 break; 664 case PCM_PARAM_PERIOD_BYTES: 665 return SNDRV_PCM_HW_PARAM_PERIOD_BYTES; 666 break; 667 case PCM_PARAM_PERIODS: 668 return SNDRV_PCM_HW_PARAM_PERIODS; 669 break; 670 case PCM_PARAM_BUFFER_TIME: 671 return SNDRV_PCM_HW_PARAM_BUFFER_TIME; 672 break; 673 case PCM_PARAM_BUFFER_SIZE: 674 return SNDRV_PCM_HW_PARAM_BUFFER_SIZE; 675 break; 676 case PCM_PARAM_BUFFER_BYTES: 677 return SNDRV_PCM_HW_PARAM_BUFFER_BYTES; 678 break; 679 case PCM_PARAM_TICK_TIME: 680 return SNDRV_PCM_HW_PARAM_TICK_TIME; 681 break; 682 683 default: 684 return -1; 685 } 686 } 687 688 struct pcm_mask *pcm_params_get_mask(struct pcm_params *pcm_params, 689 enum pcm_param param) 690 { 691 int p; 692 struct snd_pcm_hw_params *params = (struct snd_pcm_hw_params *)pcm_params; 693 if (params == NULL) { 694 return NULL; 695 } 696 697 p = pcm_param_to_alsa(param); 698 if (p < 0 || !param_is_mask(p)) { 699 return NULL; 700 } 701 702 return (struct pcm_mask *)param_to_mask(params, p); 703 } 704 705 unsigned int pcm_params_get_min(struct pcm_params *pcm_params, 706 enum pcm_param param) 707 { 708 struct snd_pcm_hw_params *params = (struct snd_pcm_hw_params *)pcm_params; 709 int p; 710 711 if (!params) 712 return 0; 713 714 p = pcm_param_to_alsa(param); 715 if (p < 0) 716 return 0; 717 718 return param_get_min(params, p); 719 } 720 721 void pcm_params_set_min(struct pcm_params *pcm_params, 722 enum pcm_param param, unsigned int val) 723 { 724 struct snd_pcm_hw_params *params = (struct snd_pcm_hw_params *)pcm_params; 725 int p; 726 727 if (!params) 728 return; 729 730 p = pcm_param_to_alsa(param); 731 if (p < 0) 732 return; 733 734 param_set_min(params, p, val); 735 } 736 737 unsigned int pcm_params_get_max(struct pcm_params *pcm_params, 738 enum pcm_param param) 739 { 740 struct snd_pcm_hw_params *params = (struct snd_pcm_hw_params *)pcm_params; 741 int p; 742 743 if (!params) 744 return 0; 745 746 p = pcm_param_to_alsa(param); 747 if (p < 0) 748 return 0; 749 750 return param_get_max(params, p); 751 } 752 753 void pcm_params_set_max(struct pcm_params *pcm_params, 754 enum pcm_param param, unsigned int val) 755 { 756 struct snd_pcm_hw_params *params = (struct snd_pcm_hw_params *)pcm_params; 757 int p; 758 759 if (!params) 760 return; 761 762 p = pcm_param_to_alsa(param); 763 if (p < 0) 764 return; 765 766 param_set_max(params, p, val); 767 } 768 769 static int pcm_mask_test(struct pcm_mask *m, unsigned int index) 770 { 771 const unsigned int bitshift = 5; /* for 32 bit integer */ 772 const unsigned int bitmask = (1 << bitshift) - 1; 773 unsigned int element; 774 775 element = index >> bitshift; 776 if (element >= ARRAY_SIZE(m->bits)) 777 return 0; /* for safety, but should never occur */ 778 return (m->bits[element] >> (index & bitmask)) & 1; 779 } 780 781 static int pcm_mask_to_string(struct pcm_mask *m, char *string, unsigned int size, 782 char *mask_name, 783 const char * const *bit_array_name, size_t bit_array_size) 784 { 785 unsigned int i; 786 unsigned int offset = 0; 787 788 if (m == NULL) 789 return 0; 790 if (bit_array_size < 32) { 791 STRLOG(string, offset, size, "%12s:\t%#08x\n", mask_name, m->bits[0]); 792 } else { /* spans two or more bitfields, print with an array index */ 793 for (i = 0; i < (bit_array_size + 31) >> 5; ++i) { 794 STRLOG(string, offset, size, "%9s[%d]:\t%#08x\n", 795 mask_name, i, m->bits[i]); 796 } 797 } 798 for (i = 0; i < bit_array_size; ++i) { 799 if (pcm_mask_test(m, i)) { 800 STRLOG(string, offset, size, "%12s \t%s\n", "", bit_array_name[i]); 801 } 802 } 803 return offset; 804 } 805 806 int pcm_params_to_string(struct pcm_params *params, char *string, unsigned int size) 807 { 808 struct pcm_mask *m; 809 unsigned int min, max; 810 unsigned int clipoffset, offset; 811 812 m = pcm_params_get_mask(params, PCM_PARAM_ACCESS); 813 offset = pcm_mask_to_string(m, string, size, 814 "Access", access_lookup, ARRAY_SIZE(access_lookup)); 815 m = pcm_params_get_mask(params, PCM_PARAM_FORMAT); 816 clipoffset = offset > size ? size : offset; 817 offset += pcm_mask_to_string(m, string + clipoffset, size - clipoffset, 818 "Format", format_lookup, ARRAY_SIZE(format_lookup)); 819 m = pcm_params_get_mask(params, PCM_PARAM_SUBFORMAT); 820 clipoffset = offset > size ? size : offset; 821 offset += pcm_mask_to_string(m, string + clipoffset, size - clipoffset, 822 "Subformat", subformat_lookup, ARRAY_SIZE(subformat_lookup)); 823 min = pcm_params_get_min(params, PCM_PARAM_RATE); 824 max = pcm_params_get_max(params, PCM_PARAM_RATE); 825 STRLOG(string, offset, size, " Rate:\tmin=%uHz\tmax=%uHz\n", min, max); 826 min = pcm_params_get_min(params, PCM_PARAM_CHANNELS); 827 max = pcm_params_get_max(params, PCM_PARAM_CHANNELS); 828 STRLOG(string, offset, size, " Channels:\tmin=%u\t\tmax=%u\n", min, max); 829 min = pcm_params_get_min(params, PCM_PARAM_SAMPLE_BITS); 830 max = pcm_params_get_max(params, PCM_PARAM_SAMPLE_BITS); 831 STRLOG(string, offset, size, " Sample bits:\tmin=%u\t\tmax=%u\n", min, max); 832 min = pcm_params_get_min(params, PCM_PARAM_PERIOD_SIZE); 833 max = pcm_params_get_max(params, PCM_PARAM_PERIOD_SIZE); 834 STRLOG(string, offset, size, " Period size:\tmin=%u\t\tmax=%u\n", min, max); 835 min = pcm_params_get_min(params, PCM_PARAM_PERIODS); 836 max = pcm_params_get_max(params, PCM_PARAM_PERIODS); 837 STRLOG(string, offset, size, "Period count:\tmin=%u\t\tmax=%u\n", min, max); 838 return offset; 839 } 840 841 int pcm_params_format_test(struct pcm_params *params, enum pcm_format format) 842 { 843 unsigned int alsa_format = pcm_format_to_alsa(format); 844 845 if (alsa_format == SNDRV_PCM_FORMAT_S16_LE && format != PCM_FORMAT_S16_LE) 846 return 0; /* caution: format not recognized is equivalent to S16_LE */ 847 return pcm_mask_test(pcm_params_get_mask(params, PCM_PARAM_FORMAT), alsa_format); 848 } 849 850 int pcm_close(struct pcm *pcm) 851 { 852 if (pcm == &bad_pcm) 853 return 0; 854 855 pcm_hw_munmap_status(pcm); 856 857 if (pcm->flags & PCM_MMAP) { 858 pcm_stop(pcm); 859 munmap(pcm->mmap_buffer, pcm_frames_to_bytes(pcm, pcm->buffer_size)); 860 } 861 862 if (pcm->fd >= 0) 863 close(pcm->fd); 864 pcm->prepared = 0; 865 pcm->running = 0; 866 pcm->buffer_size = 0; 867 pcm->fd = -1; 868 free(pcm); 869 return 0; 870 } 871 872 struct pcm *pcm_open(unsigned int card, unsigned int device, 873 unsigned int flags, struct pcm_config *config) 874 { 875 struct pcm *pcm; 876 struct snd_pcm_info info; 877 struct snd_pcm_hw_params params; 878 struct snd_pcm_sw_params sparams; 879 char fn[256]; 880 int rc; 881 882 pcm = calloc(1, sizeof(struct pcm)); 883 if (!pcm || !config) 884 return &bad_pcm; /* TODO: could support default config here */ 885 886 pcm->config = *config; 887 888 snprintf(fn, sizeof(fn), "/dev/snd/pcmC%uD%u%c", card, device, 889 flags & PCM_IN ? 'c' : 'p'); 890 891 pcm->flags = flags; 892 pcm->fd = open(fn, O_RDWR|O_NONBLOCK); 893 if (pcm->fd < 0) { 894 oops(pcm, errno, "cannot open device '%s'", fn); 895 return pcm; 896 } 897 898 if (fcntl(pcm->fd, F_SETFL, fcntl(pcm->fd, F_GETFL) & 899 ~O_NONBLOCK) < 0) { 900 oops(pcm, errno, "failed to reset blocking mode '%s'", fn); 901 goto fail_close; 902 } 903 904 if (ioctl(pcm->fd, SNDRV_PCM_IOCTL_INFO, &info)) { 905 oops(pcm, errno, "cannot get info"); 906 goto fail_close; 907 } 908 pcm->subdevice = info.subdevice; 909 910 param_init(¶ms); 911 param_set_mask(¶ms, SNDRV_PCM_HW_PARAM_FORMAT, 912 pcm_format_to_alsa(config->format)); 913 param_set_mask(¶ms, SNDRV_PCM_HW_PARAM_SUBFORMAT, 914 SNDRV_PCM_SUBFORMAT_STD); 915 param_set_min(¶ms, SNDRV_PCM_HW_PARAM_PERIOD_SIZE, config->period_size); 916 param_set_int(¶ms, SNDRV_PCM_HW_PARAM_SAMPLE_BITS, 917 pcm_format_to_bits(config->format)); 918 param_set_int(¶ms, SNDRV_PCM_HW_PARAM_FRAME_BITS, 919 pcm_format_to_bits(config->format) * config->channels); 920 param_set_int(¶ms, SNDRV_PCM_HW_PARAM_CHANNELS, 921 config->channels); 922 param_set_int(¶ms, SNDRV_PCM_HW_PARAM_PERIODS, config->period_count); 923 param_set_int(¶ms, SNDRV_PCM_HW_PARAM_RATE, config->rate); 924 925 if (flags & PCM_NOIRQ) { 926 if (!(flags & PCM_MMAP)) { 927 oops(pcm, -EINVAL, "noirq only currently supported with mmap()."); 928 goto fail_close; 929 } 930 931 params.flags |= SNDRV_PCM_HW_PARAMS_NO_PERIOD_WAKEUP; 932 pcm->noirq_frames_per_msec = config->rate / 1000; 933 } 934 935 if (flags & PCM_MMAP) 936 param_set_mask(¶ms, SNDRV_PCM_HW_PARAM_ACCESS, 937 SNDRV_PCM_ACCESS_MMAP_INTERLEAVED); 938 else 939 param_set_mask(¶ms, SNDRV_PCM_HW_PARAM_ACCESS, 940 SNDRV_PCM_ACCESS_RW_INTERLEAVED); 941 942 if (ioctl(pcm->fd, SNDRV_PCM_IOCTL_HW_PARAMS, ¶ms)) { 943 oops(pcm, errno, "cannot set hw params"); 944 goto fail_close; 945 } 946 947 /* get our refined hw_params */ 948 config->period_size = param_get_int(¶ms, SNDRV_PCM_HW_PARAM_PERIOD_SIZE); 949 config->period_count = param_get_int(¶ms, SNDRV_PCM_HW_PARAM_PERIODS); 950 pcm->buffer_size = config->period_count * config->period_size; 951 952 if (flags & PCM_MMAP) { 953 pcm->mmap_buffer = mmap(NULL, pcm_frames_to_bytes(pcm, pcm->buffer_size), 954 PROT_READ | PROT_WRITE, MAP_FILE | MAP_SHARED, pcm->fd, 0); 955 if (pcm->mmap_buffer == MAP_FAILED) { 956 oops(pcm, -errno, "failed to mmap buffer %d bytes\n", 957 pcm_frames_to_bytes(pcm, pcm->buffer_size)); 958 goto fail_close; 959 } 960 } 961 962 memset(&sparams, 0, sizeof(sparams)); 963 sparams.tstamp_mode = SNDRV_PCM_TSTAMP_ENABLE; 964 sparams.period_step = 1; 965 966 if (!config->start_threshold) { 967 if (pcm->flags & PCM_IN) 968 pcm->config.start_threshold = sparams.start_threshold = 1; 969 else 970 pcm->config.start_threshold = sparams.start_threshold = 971 config->period_count * config->period_size / 2; 972 } else 973 sparams.start_threshold = config->start_threshold; 974 975 /* pick a high stop threshold - todo: does this need further tuning */ 976 if (!config->stop_threshold) { 977 if (pcm->flags & PCM_IN) 978 pcm->config.stop_threshold = sparams.stop_threshold = 979 config->period_count * config->period_size * 10; 980 else 981 pcm->config.stop_threshold = sparams.stop_threshold = 982 config->period_count * config->period_size; 983 } 984 else 985 sparams.stop_threshold = config->stop_threshold; 986 987 if (!pcm->config.avail_min) { 988 if (pcm->flags & PCM_MMAP) 989 pcm->config.avail_min = sparams.avail_min = pcm->config.period_size; 990 else 991 pcm->config.avail_min = sparams.avail_min = 1; 992 } else 993 sparams.avail_min = config->avail_min; 994 995 sparams.xfer_align = config->period_size / 2; /* needed for old kernels */ 996 sparams.silence_threshold = config->silence_threshold; 997 sparams.silence_size = config->silence_size; 998 pcm->boundary = sparams.boundary = pcm->buffer_size; 999 1000 while (pcm->boundary * 2 <= INT_MAX - pcm->buffer_size) 1001 pcm->boundary *= 2; 1002 1003 if (ioctl(pcm->fd, SNDRV_PCM_IOCTL_SW_PARAMS, &sparams)) { 1004 oops(pcm, errno, "cannot set sw params"); 1005 goto fail; 1006 } 1007 1008 rc = pcm_hw_mmap_status(pcm); 1009 if (rc < 0) { 1010 oops(pcm, rc, "mmap status failed"); 1011 goto fail; 1012 } 1013 1014 #ifdef SNDRV_PCM_IOCTL_TTSTAMP 1015 if (pcm->flags & PCM_MONOTONIC) { 1016 int arg = SNDRV_PCM_TSTAMP_TYPE_MONOTONIC; 1017 rc = ioctl(pcm->fd, SNDRV_PCM_IOCTL_TTSTAMP, &arg); 1018 if (rc < 0) { 1019 oops(pcm, rc, "cannot set timestamp type"); 1020 goto fail; 1021 } 1022 } 1023 #endif 1024 1025 pcm->underruns = 0; 1026 return pcm; 1027 1028 fail: 1029 if (flags & PCM_MMAP) 1030 munmap(pcm->mmap_buffer, pcm_frames_to_bytes(pcm, pcm->buffer_size)); 1031 fail_close: 1032 close(pcm->fd); 1033 pcm->fd = -1; 1034 return pcm; 1035 } 1036 1037 int pcm_is_ready(struct pcm *pcm) 1038 { 1039 return pcm->fd >= 0; 1040 } 1041 1042 int pcm_prepare(struct pcm *pcm) 1043 { 1044 if (pcm->prepared) 1045 return 0; 1046 1047 if (ioctl(pcm->fd, SNDRV_PCM_IOCTL_PREPARE) < 0) 1048 return oops(pcm, errno, "cannot prepare channel"); 1049 1050 pcm->prepared = 1; 1051 return 0; 1052 } 1053 1054 int pcm_start(struct pcm *pcm) 1055 { 1056 int prepare_error = pcm_prepare(pcm); 1057 if (prepare_error) 1058 return prepare_error; 1059 1060 if (pcm->flags & PCM_MMAP) 1061 pcm_sync_ptr(pcm, 0); 1062 1063 if (ioctl(pcm->fd, SNDRV_PCM_IOCTL_START) < 0) 1064 return oops(pcm, errno, "cannot start channel"); 1065 1066 pcm->running = 1; 1067 return 0; 1068 } 1069 1070 int pcm_stop(struct pcm *pcm) 1071 { 1072 if (ioctl(pcm->fd, SNDRV_PCM_IOCTL_DROP) < 0) 1073 return oops(pcm, errno, "cannot stop channel"); 1074 1075 pcm->prepared = 0; 1076 pcm->running = 0; 1077 return 0; 1078 } 1079 1080 static inline int pcm_mmap_playback_avail(struct pcm *pcm) 1081 { 1082 int avail; 1083 1084 avail = pcm->mmap_status->hw_ptr + pcm->buffer_size - pcm->mmap_control->appl_ptr; 1085 1086 if (avail < 0) 1087 avail += pcm->boundary; 1088 else if (avail > (int)pcm->boundary) 1089 avail -= pcm->boundary; 1090 1091 return avail; 1092 } 1093 1094 static inline int pcm_mmap_capture_avail(struct pcm *pcm) 1095 { 1096 int avail = pcm->mmap_status->hw_ptr - pcm->mmap_control->appl_ptr; 1097 if (avail < 0) 1098 avail += pcm->boundary; 1099 return avail; 1100 } 1101 1102 int pcm_mmap_avail(struct pcm *pcm) 1103 { 1104 pcm_sync_ptr(pcm, SNDRV_PCM_SYNC_PTR_HWSYNC); 1105 if (pcm->flags & PCM_IN) 1106 return pcm_mmap_capture_avail(pcm); 1107 else 1108 return pcm_mmap_playback_avail(pcm); 1109 } 1110 1111 static void pcm_mmap_appl_forward(struct pcm *pcm, int frames) 1112 { 1113 unsigned int appl_ptr = pcm->mmap_control->appl_ptr; 1114 appl_ptr += frames; 1115 1116 /* check for boundary wrap */ 1117 if (appl_ptr > pcm->boundary) 1118 appl_ptr -= pcm->boundary; 1119 pcm->mmap_control->appl_ptr = appl_ptr; 1120 } 1121 1122 int pcm_mmap_begin(struct pcm *pcm, void **areas, unsigned int *offset, 1123 unsigned int *frames) 1124 { 1125 unsigned int continuous, copy_frames, avail; 1126 1127 /* return the mmap buffer */ 1128 *areas = pcm->mmap_buffer; 1129 1130 /* and the application offset in frames */ 1131 *offset = pcm->mmap_control->appl_ptr % pcm->buffer_size; 1132 1133 avail = pcm_mmap_avail(pcm); 1134 if (avail > pcm->buffer_size) 1135 avail = pcm->buffer_size; 1136 continuous = pcm->buffer_size - *offset; 1137 1138 /* we can only copy frames if the are availabale and continuos */ 1139 copy_frames = *frames; 1140 if (copy_frames > avail) 1141 copy_frames = avail; 1142 if (copy_frames > continuous) 1143 copy_frames = continuous; 1144 *frames = copy_frames; 1145 1146 return 0; 1147 } 1148 1149 int pcm_mmap_commit(struct pcm *pcm, unsigned int offset __attribute__((unused)), unsigned int frames) 1150 { 1151 /* update the application pointer in userspace and kernel */ 1152 pcm_mmap_appl_forward(pcm, frames); 1153 pcm_sync_ptr(pcm, 0); 1154 1155 return frames; 1156 } 1157 1158 int pcm_avail_update(struct pcm *pcm) 1159 { 1160 pcm_sync_ptr(pcm, 0); 1161 return pcm_mmap_avail(pcm); 1162 } 1163 1164 int pcm_state(struct pcm *pcm) 1165 { 1166 int err = pcm_sync_ptr(pcm, 0); 1167 if (err < 0) 1168 return err; 1169 1170 return pcm->mmap_status->state; 1171 } 1172 1173 int pcm_set_avail_min(struct pcm *pcm, int avail_min) 1174 { 1175 if ((~pcm->flags) & (PCM_MMAP | PCM_NOIRQ)) 1176 return -ENOSYS; 1177 1178 pcm->config.avail_min = avail_min; 1179 return 0; 1180 } 1181 1182 int pcm_wait(struct pcm *pcm, int timeout) 1183 { 1184 struct pollfd pfd; 1185 int err; 1186 1187 pfd.fd = pcm->fd; 1188 pfd.events = POLLOUT | POLLERR | POLLNVAL; 1189 1190 do { 1191 /* let's wait for avail or timeout */ 1192 err = poll(&pfd, 1, timeout); 1193 if (err < 0) 1194 return -errno; 1195 1196 /* timeout ? */ 1197 if (err == 0) 1198 return 0; 1199 1200 /* have we been interrupted ? */ 1201 if (errno == -EINTR) 1202 continue; 1203 1204 /* check for any errors */ 1205 if (pfd.revents & (POLLERR | POLLNVAL)) { 1206 switch (pcm_state(pcm)) { 1207 case PCM_STATE_XRUN: 1208 return -EPIPE; 1209 case PCM_STATE_SUSPENDED: 1210 return -ESTRPIPE; 1211 case PCM_STATE_DISCONNECTED: 1212 return -ENODEV; 1213 default: 1214 return -EIO; 1215 } 1216 } 1217 /* poll again if fd not ready for IO */ 1218 } while (!(pfd.revents & (POLLIN | POLLOUT))); 1219 1220 return 1; 1221 } 1222 1223 int pcm_get_poll_fd(struct pcm *pcm) 1224 { 1225 return pcm->fd; 1226 } 1227 1228 int pcm_mmap_transfer(struct pcm *pcm, const void *buffer, unsigned int bytes) 1229 { 1230 int err = 0, frames, avail; 1231 unsigned int offset = 0, count; 1232 1233 if (bytes == 0) 1234 return 0; 1235 1236 count = pcm_bytes_to_frames(pcm, bytes); 1237 1238 while (count > 0) { 1239 1240 /* get the available space for writing new frames */ 1241 avail = pcm_avail_update(pcm); 1242 if (avail < 0) { 1243 fprintf(stderr, "cannot determine available mmap frames"); 1244 return err; 1245 } 1246 1247 /* start the audio if we reach the threshold */ 1248 if (!pcm->running && 1249 (pcm->buffer_size - avail) >= pcm->config.start_threshold) { 1250 if (pcm_start(pcm) < 0) { 1251 fprintf(stderr, "start error: hw 0x%x app 0x%x avail 0x%x\n", 1252 (unsigned int)pcm->mmap_status->hw_ptr, 1253 (unsigned int)pcm->mmap_control->appl_ptr, 1254 avail); 1255 return -errno; 1256 } 1257 pcm->wait_for_avail_min = 0; 1258 } 1259 1260 /* sleep until we have space to write new frames */ 1261 if (pcm->running) { 1262 /* enable waiting for avail_min threshold when less frames than we have to write 1263 * are available. */ 1264 if (!pcm->wait_for_avail_min && (count > (unsigned int)avail)) 1265 pcm->wait_for_avail_min = 1; 1266 1267 if (pcm->wait_for_avail_min && (avail < pcm->config.avail_min)) { 1268 int time = -1; 1269 1270 /* disable waiting for avail_min threshold to allow small amounts of data to be 1271 * written without waiting as long as there is enough room in buffer. */ 1272 pcm->wait_for_avail_min = 0; 1273 1274 if (pcm->flags & PCM_NOIRQ) 1275 time = (pcm->config.avail_min - avail) / pcm->noirq_frames_per_msec; 1276 1277 err = pcm_wait(pcm, time); 1278 if (err < 0) { 1279 pcm->prepared = 0; 1280 pcm->running = 0; 1281 oops(pcm, err, "wait error: hw 0x%x app 0x%x avail 0x%x\n", 1282 (unsigned int)pcm->mmap_status->hw_ptr, 1283 (unsigned int)pcm->mmap_control->appl_ptr, 1284 avail); 1285 pcm->mmap_control->appl_ptr = 0; 1286 return err; 1287 } 1288 continue; 1289 } 1290 } 1291 1292 frames = count; 1293 if (frames > avail) 1294 frames = avail; 1295 1296 if (!frames) 1297 break; 1298 1299 /* copy frames from buffer */ 1300 frames = pcm_mmap_transfer_areas(pcm, (void *)buffer, offset, frames); 1301 if (frames < 0) { 1302 fprintf(stderr, "write error: hw 0x%x app 0x%x avail 0x%x\n", 1303 (unsigned int)pcm->mmap_status->hw_ptr, 1304 (unsigned int)pcm->mmap_control->appl_ptr, 1305 avail); 1306 return frames; 1307 } 1308 1309 offset += frames; 1310 count -= frames; 1311 } 1312 1313 return 0; 1314 } 1315 1316 int pcm_mmap_write(struct pcm *pcm, const void *data, unsigned int count) 1317 { 1318 if ((~pcm->flags) & (PCM_OUT | PCM_MMAP)) 1319 return -ENOSYS; 1320 1321 return pcm_mmap_transfer(pcm, (void *)data, count); 1322 } 1323 1324 int pcm_mmap_read(struct pcm *pcm, void *data, unsigned int count) 1325 { 1326 if ((~pcm->flags) & (PCM_IN | PCM_MMAP)) 1327 return -ENOSYS; 1328 1329 return pcm_mmap_transfer(pcm, data, count); 1330 } 1331 1332 int pcm_ioctl(struct pcm *pcm, int request, ...) 1333 { 1334 va_list ap; 1335 void * arg; 1336 1337 if (!pcm_is_ready(pcm)) 1338 return -1; 1339 1340 va_start(ap, request); 1341 arg = va_arg(ap, void *); 1342 va_end(ap); 1343 1344 return ioctl(pcm->fd, request, arg); 1345 } 1346
