audio/sndioaudio.c

   1 /*
   2  * SPDX-License-Identifier: ISC
   3  *
   4  * Copyright (c) 2019 Alexandre Ratchov <alex@caoua.org>
   5  */
   6
   7 /*
   8  * TODO :
   9  *
  10  * Use a single device and open it in full-duplex rather than
  11  * opening it twice (once for playback once for recording).
  12  *
  13  * This is the only way to ensure that playback doesn't drift with respect
  14  * to recording, which is what guest systems expect.
  15  */
  16
  17 #include "qemu/osdep.h"
  18 #include <poll.h>
  19 #include <sndio.h>
  20 #include "qemu/main-loop.h"
  21 #include "audio.h"
  22 #include "trace.h"
  23
  24 #define AUDIO_CAP "sndio"
  25 #include "audio_int.h"
  26
  27 /* default latency in microseconds if no option is set */
  28 #define SNDIO_LATENCY_US   50000
  29
  30 typedef struct SndioVoice {
  31     union {
  32         HWVoiceOut out;
  33         HWVoiceIn in;
  34     } hw;
  35     struct sio_par par;
  36     struct sio_hdl *hdl;
  37     struct pollfd *pfds;
  38     struct pollindex {
  39         struct SndioVoice *self;
  40         int index;
  41     } *pindexes;
  42     unsigned char *buf;
  43     size_t buf_size;
  44     size_t sndio_pos;
  45     size_t qemu_pos;
  46     unsigned int mode;
  47     unsigned int nfds;
  48     bool enabled;
  49 } SndioVoice;
  50
  51 typedef struct SndioConf {
  52     const char *devname;
  53     unsigned int latency;
  54 } SndioConf;
  55
  56 /* needed for forward reference */
  57 static void sndio_poll_in(void *arg);
  58 static void sndio_poll_out(void *arg);
  59
  60 /*
  61  * stop polling descriptors
  62  */
  63 static void sndio_poll_clear(SndioVoice *self)
  64 {
  65     struct pollfd *pfd;
  66     int i;
  67
  68     for (i = 0; i < self->nfds; i++) {
  69         pfd = &self->pfds[i];
  70         qemu_set_fd_handler(pfd->fd, NULL, NULL, NULL);
  71     }
  72
  73     self->nfds = 0;
  74 }
  75
  76 /*
  77  * write data to the device until it blocks or
  78  * all of our buffered data is written
  79  */
  80 static void sndio_write(SndioVoice *self)
  81 {
  82     size_t todo, n;
  83
  84     todo = self->qemu_pos - self->sndio_pos;
  85
  86     /*
  87      * transfer data to device, until it blocks
  88      */
  89     while (todo > 0) {
  90         n = sio_write(self->hdl, self->buf + self->sndio_pos, todo);
  91         if (n == 0) {
  92             break;
  93         }
  94         self->sndio_pos += n;
  95         todo -= n;
  96     }
  97
  98     if (self->sndio_pos == self->buf_size) {
  99         /*
 100          * we complete the block
 101          */
 102         self->sndio_pos = 0;
 103         self->qemu_pos = 0;
 104     }
 105 }
 106
 107 /*
 108  * read data from the device until it blocks or
 109  * there no room any longer
 110  */
 111 static void sndio_read(SndioVoice *self)
 112 {
 113     size_t todo, n;
 114
 115     todo = self->buf_size - self->sndio_pos;
 116
 117     /*
 118      * transfer data from the device, until it blocks
 119      */
 120     while (todo > 0) {
 121         n = sio_read(self->hdl, self->buf + self->sndio_pos, todo);
 122         if (n == 0) {
 123             break;
 124         }
 125         self->sndio_pos += n;
 126         todo -= n;
 127     }
 128 }
 129
 130 /*
 131  * Set handlers for all descriptors libsndio needs to
 132  * poll
 133  */
 134 static void sndio_poll_wait(SndioVoice *self)
 135 {
 136     struct pollfd *pfd;
 137     int events, i;
 138
 139     events = 0;
 140     if (self->mode == SIO_PLAY) {
 141         if (self->sndio_pos < self->qemu_pos) {
 142             events |= POLLOUT;
 143         }
 144     } else {
 145         if (self->sndio_pos < self->buf_size) {
 146             events |= POLLIN;
 147         }
 148     }
 149
 150     /*
 151      * fill the given array of descriptors with the events sndio
 152      * wants, they are different from our 'event' variable because
 153      * sndio may use descriptors internally.
 154      */
 155     self->nfds = sio_pollfd(self->hdl, self->pfds, events);
 156
 157     for (i = 0; i < self->nfds; i++) {
 158         pfd = &self->pfds[i];
 159         if (pfd->fd < 0) {
 160             continue;
 161         }
 162         qemu_set_fd_handler(pfd->fd,
 163             (pfd->events & POLLIN) ? sndio_poll_in : NULL,
 164             (pfd->events & POLLOUT) ? sndio_poll_out : NULL,
 165             &self->pindexes[i]);
 166         pfd->revents = 0;
 167     }
 168 }
 169
 170 /*
 171  * call-back called when one of the descriptors
 172  * became readable or writable
 173  */
 174 static void sndio_poll_event(SndioVoice *self, int index, int event)
 175 {
 176     int revents;
 177
 178     /*
 179      * ensure we're not called twice this cycle
 180      */
 181     sndio_poll_clear(self);
 182
 183     /*
 184      * make self->pfds[] look as we're returning from poll syscal,
 185      * this is how sio_revents expects events to be.
 186      */
 187     self->pfds[index].revents = event;
 188
 189     /*
 190      * tell sndio to handle events and return whether we can read or
 191      * write without blocking.
 192      */
 193     revents = sio_revents(self->hdl, self->pfds);
 194     if (self->mode == SIO_PLAY) {
 195         if (revents & POLLOUT) {
 196             sndio_write(self);
 197         }
 198
 199         if (self->qemu_pos < self->buf_size) {
 200             audio_run(self->hw.out.s, "sndio_out");
 201         }
 202     } else {
 203         if (revents & POLLIN) {
 204             sndio_read(self);
 205         }
 206
 207         if (self->qemu_pos < self->sndio_pos) {
 208             audio_run(self->hw.in.s, "sndio_in");
 209         }
 210     }
 211
 212     /*
 213      * audio_run() may have changed state
 214      */
 215     if (self->enabled) {
 216         sndio_poll_wait(self);
 217     }
 218 }
 219
 220 /*
 221  * return the upper limit of the amount of free play buffer space
 222  */
 223 static size_t sndio_buffer_get_free(HWVoiceOut *hw)
 224 {
 225     SndioVoice *self = (SndioVoice *) hw;
 226
 227     return self->buf_size - self->qemu_pos;
 228 }
 229
 230 /*
 231  * return a buffer where data to play can be stored,
 232  * its size is stored in the location pointed by the size argument.
 233  */
 234 static void *sndio_get_buffer_out(HWVoiceOut *hw, size_t *size)
 235 {
 236     SndioVoice *self = (SndioVoice *) hw;
 237
 238     *size = self->buf_size - self->qemu_pos;
 239     return self->buf + self->qemu_pos;
 240 }
 241
 242 /*
 243  * put back to sndio back-end a buffer returned by sndio_get_buffer_out()
 244  */
 245 static size_t sndio_put_buffer_out(HWVoiceOut *hw, void *buf, size_t size)
 246 {
 247     SndioVoice *self = (SndioVoice *) hw;
 248
 249     self->qemu_pos += size;
 250     sndio_poll_wait(self);
 251     return size;
 252 }
 253
 254 /*
 255  * return a buffer from where recorded data is available,
 256  * its size is stored in the location pointed by the size argument.
 257  * it may not exceed the initial value of "*size".
 258  */
 259 static void *sndio_get_buffer_in(HWVoiceIn *hw, size_t *size)
 260 {
 261     SndioVoice *self = (SndioVoice *) hw;
 262     size_t todo, max_todo;
 263
 264     /*
 265      * unlike the get_buffer_out() method, get_buffer_in()
 266      * must return a buffer of at most the given size, see audio.c
 267      */
 268     max_todo = *size;
 269
 270     todo = self->sndio_pos - self->qemu_pos;
 271     if (todo > max_todo) {
 272         todo = max_todo;
 273     }
 274
 275     *size = todo;
 276     return self->buf + self->qemu_pos;
 277 }
 278
 279 /*
 280  * discard the given amount of recorded data
 281  */
 282 static void sndio_put_buffer_in(HWVoiceIn *hw, void *buf, size_t size)
 283 {
 284     SndioVoice *self = (SndioVoice *) hw;
 285
 286     self->qemu_pos += size;
 287     if (self->qemu_pos == self->buf_size) {
 288         self->qemu_pos = 0;
 289         self->sndio_pos = 0;
 290     }
 291     sndio_poll_wait(self);
 292 }
 293
 294 /*
 295  * call-back called when one of our descriptors becomes writable
 296  */
 297 static void sndio_poll_out(void *arg)
 298 {
 299     struct pollindex *pindex = (struct pollindex *) arg;
 300
 301     sndio_poll_event(pindex->self, pindex->index, POLLOUT);
 302 }
 303
 304 /*
 305  * call-back called when one of our descriptors becomes readable
 306  */
 307 static void sndio_poll_in(void *arg)
 308 {
 309     struct pollindex *pindex = (struct pollindex *) arg;
 310
 311     sndio_poll_event(pindex->self, pindex->index, POLLIN);
 312 }
 313
 314 static void sndio_fini(SndioVoice *self)
 315 {
 316     if (self->hdl) {
 317         sio_close(self->hdl);
 318         self->hdl = NULL;
 319     }
 320
 321     g_free(self->pfds);
 322     g_free(self->pindexes);
 323     g_free(self->buf);
 324 }
 325
 326 static int sndio_init(SndioVoice *self,
 327                       struct audsettings *as, int mode, Audiodev *dev)
 328 {
 329     AudiodevSndioOptions *opts = &dev->u.sndio;
 330     unsigned long long latency;
 331     const char *dev_name;
 332     struct sio_par req;
 333     unsigned int nch;
 334     int i, nfds;
 335
 336     dev_name = opts->dev ?: SIO_DEVANY;
 337     latency = opts->has_latency ? opts->latency : SNDIO_LATENCY_US;
 338
 339     /* open the device in non-blocking mode */
 340     self->hdl = sio_open(dev_name, mode, 1);
 341     if (self->hdl == NULL) {
 342         dolog("failed to open device\n");
 343         return -1;
 344     }
 345
 346     self->mode = mode;
 347
 348     sio_initpar(&req);
 349
 350     switch (as->fmt) {
 351     case AUDIO_FORMAT_S8:
 352         req.bits = 8;
 353         req.sig = 1;
 354         break;
 355     case AUDIO_FORMAT_U8:
 356         req.bits = 8;
 357         req.sig = 0;
 358         break;
 359     case AUDIO_FORMAT_S16:
 360         req.bits = 16;
 361         req.sig = 1;
 362         break;
 363     case AUDIO_FORMAT_U16:
 364         req.bits = 16;
 365         req.sig = 0;
 366         break;
 367     case AUDIO_FORMAT_S32:
 368         req.bits = 32;
 369         req.sig = 1;
 370         break;
 371     case AUDIO_FORMAT_U32:
 372         req.bits = 32;
 373         req.sig = 0;
 374         break;
 375     default:
 376         dolog("unknown audio sample format\n");
 377         return -1;
 378     }
 379
 380     if (req.bits > 8) {
 381         req.le = as->endianness ? 0 : 1;
 382     }
 383
 384     req.rate = as->freq;
 385     if (mode == SIO_PLAY) {
 386         req.pchan = as->nchannels;
 387     } else {
 388         req.rchan = as->nchannels;
 389     }
 390
 391     /* set on-device buffer size */
 392     req.appbufsz = req.rate * latency / 1000000;
 393
 394     if (!sio_setpar(self->hdl, &req)) {
 395         dolog("failed set audio params\n");
 396         goto fail;
 397     }
 398
 399     if (!sio_getpar(self->hdl, &self->par)) {
 400         dolog("failed get audio params\n");
 401         goto fail;
 402     }
 403
 404     nch = (mode == SIO_PLAY) ? self->par.pchan : self->par.rchan;
 405
 406     /*
 407      * With the default setup, sndio supports any combination of parameters
 408      * so these checks are mostly to catch configuration errors.
 409      */
 410     if (self->par.bits != req.bits || self->par.bps != req.bits / 8 ||
 411         self->par.sig != req.sig || (req.bits > 8 && self->par.le != req.le) ||
 412         self->par.rate != as->freq || nch != as->nchannels) {
 413         dolog("unsupported audio params\n");
 414         goto fail;
 415     }
 416
 417     /*
 418      * we use one block as buffer size; this is how
 419      * transfers get well aligned
 420      */
 421     self->buf_size = self->par.round * self->par.bps * nch;
 422
 423     self->buf = g_malloc(self->buf_size);
 424     if (self->buf == NULL) {
 425         dolog("failed to allocate audio buffer\n");
 426         goto fail;
 427     }
 428
 429     nfds = sio_nfds(self->hdl);
 430
 431     self->pfds = g_malloc_n(nfds, sizeof(struct pollfd));
 432     if (self->pfds == NULL) {
 433         dolog("failed to allocate pollfd structures\n");
 434         goto fail;
 435     }
 436
 437     self->pindexes = g_malloc_n(nfds, sizeof(struct pollindex));
 438     if (self->pindexes == NULL) {
 439         dolog("failed to allocate pollindex structures\n");
 440         goto fail;
 441     }
 442
 443     for (i = 0; i < nfds; i++) {
 444         self->pindexes[i].self = self;
 445         self->pindexes[i].index = i;
 446     }
 447
 448     return 0;
 449 fail:
 450     sndio_fini(self);
 451     return -1;
 452 }
 453
 454 static void sndio_enable(SndioVoice *self, bool enable)
 455 {
 456     if (enable) {
 457         sio_start(self->hdl);
 458         self->enabled = true;
 459         sndio_poll_wait(self);
 460     } else {
 461         self->enabled = false;
 462         sndio_poll_clear(self);
 463         sio_stop(self->hdl);
 464     }
 465 }
 466
 467 static void sndio_enable_out(HWVoiceOut *hw, bool enable)
 468 {
 469     SndioVoice *self = (SndioVoice *) hw;
 470
 471     sndio_enable(self, enable);
 472 }
 473
 474 static void sndio_enable_in(HWVoiceIn *hw, bool enable)
 475 {
 476     SndioVoice *self = (SndioVoice *) hw;
 477
 478     sndio_enable(self, enable);
 479 }
 480
 481 static int sndio_init_out(HWVoiceOut *hw, struct audsettings *as, void *opaque)
 482 {
 483     SndioVoice *self = (SndioVoice *) hw;
 484
 485     if (sndio_init(self, as, SIO_PLAY, opaque) == -1) {
 486         return -1;
 487     }
 488
 489     audio_pcm_init_info(&hw->info, as);
 490     hw->samples = self->par.round;
 491     return 0;
 492 }
 493
 494 static int sndio_init_in(HWVoiceIn *hw, struct audsettings *as, void *opaque)
 495 {
 496     SndioVoice *self = (SndioVoice *) hw;
 497
 498     if (sndio_init(self, as, SIO_REC, opaque) == -1) {
 499         return -1;
 500     }
 501
 502     audio_pcm_init_info(&hw->info, as);
 503     hw->samples = self->par.round;
 504     return 0;
 505 }
 506
 507 static void sndio_fini_out(HWVoiceOut *hw)
 508 {
 509     SndioVoice *self = (SndioVoice *) hw;
 510
 511     sndio_fini(self);
 512 }
 513
 514 static void sndio_fini_in(HWVoiceIn *hw)
 515 {
 516     SndioVoice *self = (SndioVoice *) hw;
 517
 518     sndio_fini(self);
 519 }
 520
 521 static void *sndio_audio_init(Audiodev *dev, Error **errp)
 522 {
 523     assert(dev->driver == AUDIODEV_DRIVER_SNDIO);
 524     return dev;
 525 }
 526
 527 static void sndio_audio_fini(void *opaque)
 528 {
 529 }
 530
 531 static struct audio_pcm_ops sndio_pcm_ops = {
 532     .init_out        = sndio_init_out,
 533     .fini_out        = sndio_fini_out,
 534     .enable_out      = sndio_enable_out,
 535     .write           = audio_generic_write,
 536     .buffer_get_free = sndio_buffer_get_free,
 537     .get_buffer_out  = sndio_get_buffer_out,
 538     .put_buffer_out  = sndio_put_buffer_out,
 539     .init_in         = sndio_init_in,
 540     .fini_in         = sndio_fini_in,
 541     .read            = audio_generic_read,
 542     .enable_in       = sndio_enable_in,
 543     .get_buffer_in   = sndio_get_buffer_in,
 544     .put_buffer_in   = sndio_put_buffer_in,
 545 };
 546
 547 static struct audio_driver sndio_audio_driver = {
 548     .name           = "sndio",
 549     .descr          = "sndio https://sndio.org",
 550     .init           = sndio_audio_init,
 551     .fini           = sndio_audio_fini,
 552     .pcm_ops        = &sndio_pcm_ops,
 553     .max_voices_out = INT_MAX,
 554     .max_voices_in  = INT_MAX,
 555     .voice_size_out = sizeof(SndioVoice),
 556     .voice_size_in  = sizeof(SndioVoice)
 557 };
 558
 559 static void register_audio_sndio(void)
 560 {
 561     audio_driver_register(&sndio_audio_driver);
 562 }
 563
 564 type_init(register_audio_sndio);