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 #define SNDRV_PCM_HW_PARAMS_NO_PERIOD_WAKEUP (1<<2) 53 54 static inline int param_is_mask(int p) 55 { 56 return (p >= SNDRV_PCM_HW_PARAM_FIRST_MASK) && 57 (p <= SNDRV_PCM_HW_PARAM_LAST_MASK); 58 } 59 60 static inline int param_is_interval(int p) 61 { 62 return (p >= SNDRV_PCM_HW_PARAM_FIRST_INTERVAL) && 63 (p <= SNDRV_PCM_HW_PARAM_LAST_INTERVAL); 64 } 65 66 static inline struct snd_interval *param_to_interval(struct snd_pcm_hw_params *p, int n) 67 { 68 return &(p->intervals[n - SNDRV_PCM_HW_PARAM_FIRST_INTERVAL]); 69 } 70 71 static inline struct snd_mask *param_to_mask(struct snd_pcm_hw_params *p, int n) 72 { 73 return &(p->masks[n - SNDRV_PCM_HW_PARAM_FIRST_MASK]); 74 } 75 76 static void param_set_mask(struct snd_pcm_hw_params *p, int n, unsigned int bit) 77 { 78 if (bit >= SNDRV_MASK_MAX) 79 return; 80 if (param_is_mask(n)) { 81 struct snd_mask *m = param_to_mask(p, n); 82 m->bits[0] = 0; 83 m->bits[1] = 0; 84 m->bits[bit >> 5] |= (1 << (bit & 31)); 85 } 86 } 87 88 static void param_set_min(struct snd_pcm_hw_params *p, int n, unsigned int val) 89 { 90 if (param_is_interval(n)) { 91 struct snd_interval *i = param_to_interval(p, n); 92 i->min = val; 93 } 94 } 95 96 static void param_set_max(struct snd_pcm_hw_params *p, int n, unsigned int val) 97 { 98 if (param_is_interval(n)) { 99 struct snd_interval *i = param_to_interval(p, n); 100 i->max = val; 101 } 102 } 103 104 static void param_set_int(struct snd_pcm_hw_params *p, int n, unsigned int val) 105 { 106 if (param_is_interval(n)) { 107 struct snd_interval *i = param_to_interval(p, n); 108 i->min = val; 109 i->max = val; 110 i->integer = 1; 111 } 112 } 113 114 static unsigned int param_get_int(struct snd_pcm_hw_params *p, int n) 115 { 116 if (param_is_interval(n)) { 117 struct snd_interval *i = param_to_interval(p, n); 118 if (i->integer) 119 return i->max; 120 } 121 return 0; 122 } 123 124 static void param_init(struct snd_pcm_hw_params *p) 125 { 126 int n; 127 128 memset(p, 0, sizeof(*p)); 129 for (n = SNDRV_PCM_HW_PARAM_FIRST_MASK; 130 n <= SNDRV_PCM_HW_PARAM_LAST_MASK; n++) { 131 struct snd_mask *m = param_to_mask(p, n); 132 m->bits[0] = ~0; 133 m->bits[1] = ~0; 134 } 135 for (n = SNDRV_PCM_HW_PARAM_FIRST_INTERVAL; 136 n <= SNDRV_PCM_HW_PARAM_LAST_INTERVAL; n++) { 137 struct snd_interval *i = param_to_interval(p, n); 138 i->min = 0; 139 i->max = ~0; 140 } 141 } 142 143 #define PCM_ERROR_MAX 128 144 145 struct pcm { 146 int fd; 147 unsigned int flags; 148 int running:1; 149 int underruns; 150 unsigned int buffer_size; 151 unsigned int boundary; 152 char error[PCM_ERROR_MAX]; 153 struct pcm_config config; 154 struct snd_pcm_mmap_status *mmap_status; 155 struct snd_pcm_mmap_control *mmap_control; 156 struct snd_pcm_sync_ptr *sync_ptr; 157 void *mmap_buffer; 158 unsigned int noirq_frames_per_msec; 159 int wait_for_avail_min; 160 }; 161 162 unsigned int pcm_get_buffer_size(struct pcm *pcm) 163 { 164 return pcm->buffer_size; 165 } 166 167 const char* pcm_get_error(struct pcm *pcm) 168 { 169 return pcm->error; 170 } 171 172 static int oops(struct pcm *pcm, int e, const char *fmt, ...) 173 { 174 va_list ap; 175 int sz; 176 177 va_start(ap, fmt); 178 vsnprintf(pcm->error, PCM_ERROR_MAX, fmt, ap); 179 va_end(ap); 180 sz = strlen(pcm->error); 181 182 if (errno) 183 snprintf(pcm->error + sz, PCM_ERROR_MAX - sz, 184 ": %s", strerror(e)); 185 return -1; 186 } 187 188 static unsigned int pcm_format_to_alsa(enum pcm_format format) 189 { 190 switch (format) { 191 case PCM_FORMAT_S32_LE: 192 return SNDRV_PCM_FORMAT_S32_LE; 193 default: 194 case PCM_FORMAT_S16_LE: 195 return SNDRV_PCM_FORMAT_S16_LE; 196 }; 197 } 198 199 static unsigned int pcm_format_to_bits(enum pcm_format format) 200 { 201 switch (format) { 202 case PCM_FORMAT_S32_LE: 203 return 32; 204 default: 205 case PCM_FORMAT_S16_LE: 206 return 16; 207 }; 208 } 209 210 unsigned int pcm_bytes_to_frames(struct pcm *pcm, unsigned int bytes) 211 { 212 return bytes / (pcm->config.channels * 213 (pcm_format_to_bits(pcm->config.format) >> 3)); 214 } 215 216 unsigned int pcm_frames_to_bytes(struct pcm *pcm, unsigned int frames) 217 { 218 return frames * pcm->config.channels * 219 (pcm_format_to_bits(pcm->config.format) >> 3); 220 } 221 222 static int pcm_sync_ptr(struct pcm *pcm, int flags) { 223 if (pcm->sync_ptr) { 224 pcm->sync_ptr->flags = flags; 225 if (ioctl(pcm->fd, SNDRV_PCM_IOCTL_SYNC_PTR, pcm->sync_ptr) < 0) 226 return -1; 227 } 228 return 0; 229 } 230 231 static int pcm_hw_mmap_status(struct pcm *pcm) { 232 233 if (pcm->sync_ptr) 234 return 0; 235 236 int page_size = sysconf(_SC_PAGE_SIZE); 237 pcm->mmap_status = mmap(NULL, page_size, PROT_READ, MAP_FILE | MAP_SHARED, 238 pcm->fd, SNDRV_PCM_MMAP_OFFSET_STATUS); 239 if (pcm->mmap_status == MAP_FAILED) 240 pcm->mmap_status = NULL; 241 if (!pcm->mmap_status) 242 goto mmap_error; 243 244 pcm->mmap_control = mmap(NULL, page_size, PROT_READ | PROT_WRITE, 245 MAP_FILE | MAP_SHARED, pcm->fd, SNDRV_PCM_MMAP_OFFSET_CONTROL); 246 if (pcm->mmap_control == MAP_FAILED) 247 pcm->mmap_control = NULL; 248 if (!pcm->mmap_control) { 249 munmap(pcm->mmap_status, page_size); 250 pcm->mmap_status = NULL; 251 goto mmap_error; 252 } 253 if (pcm->flags & PCM_MMAP) 254 pcm->mmap_control->avail_min = pcm->config.avail_min; 255 else 256 pcm->mmap_control->avail_min = 1; 257 258 return 0; 259 260 mmap_error: 261 262 pcm->sync_ptr = calloc(1, sizeof(*pcm->sync_ptr)); 263 if (!pcm->sync_ptr) 264 return -ENOMEM; 265 pcm->mmap_status = &pcm->sync_ptr->s.status; 266 pcm->mmap_control = &pcm->sync_ptr->c.control; 267 if (pcm->flags & PCM_MMAP) 268 pcm->mmap_control->avail_min = pcm->config.avail_min; 269 else 270 pcm->mmap_control->avail_min = 1; 271 272 pcm_sync_ptr(pcm, 0); 273 274 return 0; 275 } 276 277 static void pcm_hw_munmap_status(struct pcm *pcm) { 278 if (pcm->sync_ptr) { 279 free(pcm->sync_ptr); 280 pcm->sync_ptr = NULL; 281 } else { 282 int page_size = sysconf(_SC_PAGE_SIZE); 283 if (pcm->mmap_status) 284 munmap(pcm->mmap_status, page_size); 285 if (pcm->mmap_control) 286 munmap(pcm->mmap_control, page_size); 287 } 288 pcm->mmap_status = NULL; 289 pcm->mmap_control = NULL; 290 } 291 292 static int pcm_areas_copy(struct pcm *pcm, unsigned int pcm_offset, 293 const char *src, unsigned int src_offset, 294 unsigned int frames) 295 { 296 int size_bytes = pcm_frames_to_bytes(pcm, frames); 297 int pcm_offset_bytes = pcm_frames_to_bytes(pcm, pcm_offset); 298 int src_offset_bytes = pcm_frames_to_bytes(pcm, src_offset); 299 300 /* interleaved only atm */ 301 memcpy((char*)pcm->mmap_buffer + pcm_offset_bytes, 302 src + src_offset_bytes, size_bytes); 303 return 0; 304 } 305 306 static int pcm_mmap_write_areas(struct pcm *pcm, const char *src, 307 unsigned int offset, unsigned int size) 308 { 309 void *pcm_areas; 310 int commit; 311 unsigned int pcm_offset, frames, count = 0; 312 313 while (size > 0) { 314 frames = size; 315 pcm_mmap_begin(pcm, &pcm_areas, &pcm_offset, &frames); 316 pcm_areas_copy(pcm, pcm_offset, src, offset, frames); 317 commit = pcm_mmap_commit(pcm, pcm_offset, frames); 318 if (commit < 0) { 319 oops(pcm, commit, "failed to commit %d frames\n", frames); 320 return commit; 321 } 322 323 offset += commit; 324 count += commit; 325 size -= commit; 326 } 327 return count; 328 } 329 330 int pcm_get_htimestamp(struct pcm *pcm, unsigned int *avail, 331 struct timespec *tstamp) 332 { 333 int frames; 334 int rc; 335 snd_pcm_uframes_t hw_ptr; 336 337 if (!pcm_is_ready(pcm)) 338 return -1; 339 340 rc = pcm_sync_ptr(pcm, SNDRV_PCM_SYNC_PTR_APPL|SNDRV_PCM_SYNC_PTR_HWSYNC); 341 if (rc < 0) 342 return -1; 343 344 if ((pcm->mmap_status->state != PCM_STATE_RUNNING) && 345 (pcm->mmap_status->state != PCM_STATE_DRAINING)) 346 return -1; 347 348 *tstamp = pcm->mmap_status->tstamp; 349 if (tstamp->tv_sec == 0 && tstamp->tv_nsec == 0) 350 return -1; 351 352 hw_ptr = pcm->mmap_status->hw_ptr; 353 if (pcm->flags & PCM_IN) 354 frames = hw_ptr - pcm->mmap_control->appl_ptr; 355 else 356 frames = hw_ptr + pcm->buffer_size - pcm->mmap_control->appl_ptr; 357 358 if (frames < 0) 359 frames += pcm->boundary; 360 else if (frames > (int)pcm->boundary) 361 frames -= pcm->boundary; 362 363 *avail = (unsigned int)frames; 364 365 return 0; 366 } 367 368 int pcm_write(struct pcm *pcm, const void *data, unsigned int count) 369 { 370 struct snd_xferi x; 371 372 if (pcm->flags & PCM_IN) 373 return -EINVAL; 374 375 x.buf = (void*)data; 376 x.frames = count / (pcm->config.channels * 377 pcm_format_to_bits(pcm->config.format) / 8); 378 379 for (;;) { 380 if (!pcm->running) { 381 if (ioctl(pcm->fd, SNDRV_PCM_IOCTL_PREPARE)) 382 return oops(pcm, errno, "cannot prepare channel"); 383 if (ioctl(pcm->fd, SNDRV_PCM_IOCTL_WRITEI_FRAMES, &x)) 384 return oops(pcm, errno, "cannot write initial data"); 385 pcm->running = 1; 386 return 0; 387 } 388 if (ioctl(pcm->fd, SNDRV_PCM_IOCTL_WRITEI_FRAMES, &x)) { 389 pcm->running = 0; 390 if (errno == EPIPE) { 391 /* we failed to make our window -- try to restart if we are 392 * allowed to do so. Otherwise, simply allow the EPIPE error to 393 * propagate up to the app level */ 394 pcm->underruns++; 395 if (pcm->flags & PCM_NORESTART) 396 return -EPIPE; 397 continue; 398 } 399 return oops(pcm, errno, "cannot write stream data"); 400 } 401 return 0; 402 } 403 } 404 405 int pcm_read(struct pcm *pcm, void *data, unsigned int count) 406 { 407 struct snd_xferi x; 408 409 if (!(pcm->flags & PCM_IN)) 410 return -EINVAL; 411 412 x.buf = data; 413 x.frames = count / (pcm->config.channels * 414 pcm_format_to_bits(pcm->config.format) / 8); 415 416 for (;;) { 417 if (!pcm->running) { 418 if (pcm_start(pcm) < 0) { 419 fprintf(stderr, "start error"); 420 return -errno; 421 } 422 } 423 if (ioctl(pcm->fd, SNDRV_PCM_IOCTL_READI_FRAMES, &x)) { 424 pcm->running = 0; 425 if (errno == EPIPE) { 426 /* we failed to make our window -- try to restart */ 427 pcm->underruns++; 428 continue; 429 } 430 return oops(pcm, errno, "cannot read stream data"); 431 } 432 return 0; 433 } 434 } 435 436 static struct pcm bad_pcm = { 437 .fd = -1, 438 }; 439 440 int pcm_close(struct pcm *pcm) 441 { 442 if (pcm == &bad_pcm) 443 return 0; 444 445 pcm_hw_munmap_status(pcm); 446 447 if (pcm->flags & PCM_MMAP) { 448 pcm_stop(pcm); 449 munmap(pcm->mmap_buffer, pcm_frames_to_bytes(pcm, pcm->buffer_size)); 450 } 451 452 if (pcm->fd >= 0) 453 close(pcm->fd); 454 pcm->running = 0; 455 pcm->buffer_size = 0; 456 pcm->fd = -1; 457 free(pcm); 458 return 0; 459 } 460 461 struct pcm *pcm_open(unsigned int card, unsigned int device, 462 unsigned int flags, struct pcm_config *config) 463 { 464 struct pcm *pcm; 465 struct snd_pcm_info info; 466 struct snd_pcm_hw_params params; 467 struct snd_pcm_sw_params sparams; 468 char fn[256]; 469 int rc; 470 471 pcm = calloc(1, sizeof(struct pcm)); 472 if (!pcm || !config) 473 return &bad_pcm; /* TODO: could support default config here */ 474 475 pcm->config = *config; 476 477 snprintf(fn, sizeof(fn), "/dev/snd/pcmC%uD%u%c", card, device, 478 flags & PCM_IN ? 'c' : 'p'); 479 480 pcm->flags = flags; 481 pcm->fd = open(fn, O_RDWR); 482 if (pcm->fd < 0) { 483 oops(pcm, errno, "cannot open device '%s'", fn); 484 return pcm; 485 } 486 487 if (ioctl(pcm->fd, SNDRV_PCM_IOCTL_INFO, &info)) { 488 oops(pcm, errno, "cannot get info"); 489 goto fail_close; 490 } 491 492 param_init(¶ms); 493 param_set_mask(¶ms, SNDRV_PCM_HW_PARAM_FORMAT, 494 pcm_format_to_alsa(config->format)); 495 param_set_mask(¶ms, SNDRV_PCM_HW_PARAM_SUBFORMAT, 496 SNDRV_PCM_SUBFORMAT_STD); 497 param_set_min(¶ms, SNDRV_PCM_HW_PARAM_PERIOD_SIZE, config->period_size); 498 param_set_int(¶ms, SNDRV_PCM_HW_PARAM_SAMPLE_BITS, 499 pcm_format_to_bits(config->format)); 500 param_set_int(¶ms, SNDRV_PCM_HW_PARAM_FRAME_BITS, 501 pcm_format_to_bits(config->format) * config->channels); 502 param_set_int(¶ms, SNDRV_PCM_HW_PARAM_CHANNELS, 503 config->channels); 504 param_set_int(¶ms, SNDRV_PCM_HW_PARAM_PERIODS, config->period_count); 505 param_set_int(¶ms, SNDRV_PCM_HW_PARAM_RATE, config->rate); 506 507 if (flags & PCM_NOIRQ) { 508 509 if (!(flags & PCM_MMAP)) { 510 oops(pcm, -EINVAL, "noirq only currently supported with mmap()."); 511 goto fail; 512 } 513 514 params.flags |= SNDRV_PCM_HW_PARAMS_NO_PERIOD_WAKEUP; 515 pcm->noirq_frames_per_msec = config->rate / 1000; 516 } 517 518 if (flags & PCM_MMAP) 519 param_set_mask(¶ms, SNDRV_PCM_HW_PARAM_ACCESS, 520 SNDRV_PCM_ACCESS_MMAP_INTERLEAVED); 521 else 522 param_set_mask(¶ms, SNDRV_PCM_HW_PARAM_ACCESS, 523 SNDRV_PCM_ACCESS_RW_INTERLEAVED); 524 525 if (ioctl(pcm->fd, SNDRV_PCM_IOCTL_HW_PARAMS, ¶ms)) { 526 oops(pcm, errno, "cannot set hw params"); 527 goto fail_close; 528 } 529 530 /* get our refined hw_params */ 531 config->period_size = param_get_int(¶ms, SNDRV_PCM_HW_PARAM_PERIOD_SIZE); 532 config->period_count = param_get_int(¶ms, SNDRV_PCM_HW_PARAM_PERIODS); 533 pcm->buffer_size = config->period_count * config->period_size; 534 535 if (flags & PCM_MMAP) { 536 pcm->mmap_buffer = mmap(NULL, pcm_frames_to_bytes(pcm, pcm->buffer_size), 537 PROT_READ | PROT_WRITE, MAP_FILE | MAP_SHARED, pcm->fd, 0); 538 if (pcm->mmap_buffer == MAP_FAILED) { 539 oops(pcm, -errno, "failed to mmap buffer %d bytes\n", 540 pcm_frames_to_bytes(pcm, pcm->buffer_size)); 541 goto fail_close; 542 } 543 } 544 545 546 memset(&sparams, 0, sizeof(sparams)); 547 sparams.tstamp_mode = SNDRV_PCM_TSTAMP_ENABLE; 548 sparams.period_step = 1; 549 550 if (!config->start_threshold) { 551 if (pcm->flags & PCM_IN) 552 pcm->config.start_threshold = sparams.start_threshold = 1; 553 else 554 pcm->config.start_threshold = sparams.start_threshold = 555 config->period_count * config->period_size / 2; 556 } else 557 sparams.start_threshold = config->start_threshold; 558 559 /* pick a high stop threshold - todo: does this need further tuning */ 560 if (!config->stop_threshold) { 561 if (pcm->flags & PCM_IN) 562 pcm->config.stop_threshold = sparams.stop_threshold = 563 config->period_count * config->period_size * 10; 564 else 565 pcm->config.stop_threshold = sparams.stop_threshold = 566 config->period_count * config->period_size; 567 } 568 else 569 sparams.stop_threshold = config->stop_threshold; 570 571 if (!pcm->config.avail_min) { 572 if (pcm->flags & PCM_MMAP) 573 pcm->config.avail_min = sparams.avail_min = pcm->config.period_size; 574 else 575 pcm->config.avail_min = sparams.avail_min = 1; 576 } else 577 sparams.avail_min = config->avail_min; 578 579 sparams.xfer_align = config->period_size / 2; /* needed for old kernels */ 580 sparams.silence_size = 0; 581 sparams.silence_threshold = config->silence_threshold; 582 pcm->boundary = sparams.boundary = pcm->buffer_size; 583 584 while (pcm->boundary * 2 <= INT_MAX - pcm->buffer_size) 585 pcm->boundary *= 2; 586 587 if (ioctl(pcm->fd, SNDRV_PCM_IOCTL_SW_PARAMS, &sparams)) { 588 oops(pcm, errno, "cannot set sw params"); 589 goto fail; 590 } 591 592 rc = pcm_hw_mmap_status(pcm); 593 if (rc < 0) { 594 oops(pcm, rc, "mmap status failed"); 595 goto fail; 596 } 597 598 pcm->underruns = 0; 599 return pcm; 600 601 fail: 602 if (flags & PCM_MMAP) 603 munmap(pcm->mmap_buffer, pcm_frames_to_bytes(pcm, pcm->buffer_size)); 604 fail_close: 605 close(pcm->fd); 606 pcm->fd = -1; 607 return pcm; 608 } 609 610 int pcm_is_ready(struct pcm *pcm) 611 { 612 return pcm->fd >= 0; 613 } 614 615 int pcm_start(struct pcm *pcm) 616 { 617 if (ioctl(pcm->fd, SNDRV_PCM_IOCTL_PREPARE) < 0) 618 return oops(pcm, errno, "cannot prepare channel"); 619 620 if (pcm->flags & PCM_MMAP) 621 pcm_sync_ptr(pcm, 0); 622 623 if (ioctl(pcm->fd, SNDRV_PCM_IOCTL_START) < 0) 624 return oops(pcm, errno, "cannot start channel"); 625 626 pcm->running = 1; 627 return 0; 628 } 629 630 int pcm_stop(struct pcm *pcm) 631 { 632 if (ioctl(pcm->fd, SNDRV_PCM_IOCTL_DROP) < 0) 633 return oops(pcm, errno, "cannot stop channel"); 634 635 pcm->running = 0; 636 return 0; 637 } 638 639 static inline int pcm_mmap_playback_avail(struct pcm *pcm) 640 { 641 int avail; 642 643 avail = pcm->mmap_status->hw_ptr + pcm->buffer_size - pcm->mmap_control->appl_ptr; 644 645 if (avail < 0) 646 avail += pcm->boundary; 647 else if (avail > (int)pcm->boundary) 648 avail -= pcm->boundary; 649 650 return avail; 651 } 652 653 static inline int pcm_mmap_capture_avail(struct pcm *pcm) 654 { 655 int avail = pcm->mmap_status->hw_ptr - pcm->mmap_control->appl_ptr; 656 if (avail < 0) 657 avail += pcm->boundary; 658 return avail; 659 } 660 661 static inline int pcm_mmap_avail(struct pcm *pcm) 662 { 663 pcm_sync_ptr(pcm, SNDRV_PCM_SYNC_PTR_HWSYNC); 664 if (pcm->flags & PCM_IN) 665 return pcm_mmap_capture_avail(pcm); 666 else 667 return pcm_mmap_playback_avail(pcm); 668 } 669 670 static void pcm_mmap_appl_forward(struct pcm *pcm, int frames) 671 { 672 unsigned int appl_ptr = pcm->mmap_control->appl_ptr; 673 appl_ptr += frames; 674 675 /* check for boundary wrap */ 676 if (appl_ptr > pcm->boundary) 677 appl_ptr -= pcm->boundary; 678 pcm->mmap_control->appl_ptr = appl_ptr; 679 } 680 681 int pcm_mmap_begin(struct pcm *pcm, void **areas, unsigned int *offset, 682 unsigned int *frames) 683 { 684 unsigned int continuous, copy_frames, avail; 685 686 /* return the mmap buffer */ 687 *areas = pcm->mmap_buffer; 688 689 /* and the application offset in frames */ 690 *offset = pcm->mmap_control->appl_ptr % pcm->buffer_size; 691 692 avail = pcm_mmap_avail(pcm); 693 if (avail > pcm->buffer_size) 694 avail = pcm->buffer_size; 695 continuous = pcm->buffer_size - *offset; 696 697 /* we can only copy frames if the are availabale and continuos */ 698 copy_frames = *frames; 699 if (copy_frames > avail) 700 copy_frames = avail; 701 if (copy_frames > continuous) 702 copy_frames = continuous; 703 *frames = copy_frames; 704 705 return 0; 706 } 707 708 int pcm_mmap_commit(struct pcm *pcm, unsigned int offset, unsigned int frames) 709 { 710 /* update the application pointer in userspace and kernel */ 711 pcm_mmap_appl_forward(pcm, frames); 712 pcm_sync_ptr(pcm, 0); 713 714 return frames; 715 } 716 717 int pcm_avail_update(struct pcm *pcm) 718 { 719 pcm_sync_ptr(pcm, 0); 720 return pcm_mmap_avail(pcm); 721 } 722 723 int pcm_state(struct pcm *pcm) 724 { 725 int err = pcm_sync_ptr(pcm, 0); 726 if (err < 0) 727 return err; 728 729 return pcm->mmap_status->state; 730 } 731 732 int pcm_set_avail_min(struct pcm *pcm, int avail_min) 733 { 734 if ((~pcm->flags) & (PCM_MMAP | PCM_NOIRQ)) 735 return -ENOSYS; 736 737 pcm->config.avail_min = avail_min; 738 return 0; 739 } 740 741 int pcm_wait(struct pcm *pcm, int timeout) 742 { 743 struct pollfd pfd; 744 unsigned short revents = 0; 745 int err; 746 747 pfd.fd = pcm->fd; 748 pfd.events = POLLOUT | POLLERR | POLLNVAL; 749 750 do { 751 /* let's wait for avail or timeout */ 752 err = poll(&pfd, 1, timeout); 753 if (err < 0) 754 return -errno; 755 756 /* timeout ? */ 757 if (err == 0) 758 return 0; 759 760 /* have we been interrupted ? */ 761 if (errno == -EINTR) 762 continue; 763 764 /* check for any errors */ 765 if (pfd.revents & (POLLERR | POLLNVAL)) { 766 switch (pcm_state(pcm)) { 767 case PCM_STATE_XRUN: 768 return -EPIPE; 769 case PCM_STATE_SUSPENDED: 770 return -ESTRPIPE; 771 case PCM_STATE_DISCONNECTED: 772 return -ENODEV; 773 default: 774 return -EIO; 775 } 776 } 777 /* poll again if fd not ready for IO */ 778 } while (!(pfd.revents & (POLLIN | POLLOUT))); 779 780 return 1; 781 } 782 783 int pcm_mmap_write(struct pcm *pcm, const void *buffer, unsigned int bytes) 784 { 785 int err = 0, frames, avail; 786 unsigned int offset = 0, count; 787 788 if (bytes == 0) 789 return 0; 790 791 count = pcm_bytes_to_frames(pcm, bytes); 792 793 while (count > 0) { 794 795 /* get the available space for writing new frames */ 796 avail = pcm_avail_update(pcm); 797 if (avail < 0) { 798 fprintf(stderr, "cannot determine available mmap frames"); 799 return err; 800 } 801 802 /* start the audio if we reach the threshold */ 803 if (!pcm->running && 804 (pcm->buffer_size - avail) >= pcm->config.start_threshold) { 805 if (pcm_start(pcm) < 0) { 806 fprintf(stderr, "start error: hw 0x%x app 0x%x avail 0x%x\n", 807 (unsigned int)pcm->mmap_status->hw_ptr, 808 (unsigned int)pcm->mmap_control->appl_ptr, 809 avail); 810 return -errno; 811 } 812 pcm->wait_for_avail_min = 0; 813 } 814 815 /* sleep until we have space to write new frames */ 816 if (pcm->running) { 817 /* enable waiting for avail_min threshold when less frames than we have to write 818 * are available. */ 819 if (!pcm->wait_for_avail_min && (count > (unsigned int)avail)) 820 pcm->wait_for_avail_min = 1; 821 822 if (pcm->wait_for_avail_min && (avail < pcm->config.avail_min)) { 823 int time = -1; 824 825 /* disable waiting for avail_min threshold to allow small amounts of data to be 826 * written without waiting as long as there is enough room in buffer. */ 827 pcm->wait_for_avail_min = 0; 828 829 if (pcm->flags & PCM_NOIRQ) 830 time = (pcm->config.avail_min - avail) / pcm->noirq_frames_per_msec; 831 832 err = pcm_wait(pcm, time); 833 if (err < 0) { 834 pcm->running = 0; 835 oops(pcm, err, "wait error: hw 0x%x app 0x%x avail 0x%x\n", 836 (unsigned int)pcm->mmap_status->hw_ptr, 837 (unsigned int)pcm->mmap_control->appl_ptr, 838 avail); 839 pcm->mmap_control->appl_ptr = 0; 840 return err; 841 } 842 continue; 843 } 844 } 845 846 frames = count; 847 if (frames > avail) 848 frames = avail; 849 850 if (!frames) 851 break; 852 853 /* copy frames from buffer */ 854 frames = pcm_mmap_write_areas(pcm, buffer, offset, frames); 855 if (frames < 0) { 856 fprintf(stderr, "write error: hw 0x%x app 0x%x avail 0x%x\n", 857 (unsigned int)pcm->mmap_status->hw_ptr, 858 (unsigned int)pcm->mmap_control->appl_ptr, 859 avail); 860 return frames; 861 } 862 863 offset += frames; 864 count -= frames; 865 } 866 867 _end: 868 return 0; 869 } 870
