qemu/audio/alsaaudio.c
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   1/*
   2 * QEMU ALSA audio driver
   3 *
   4 * Copyright (c) 2005 Vassili Karpov (malc)
   5 *
   6 * Permission is hereby granted, free of charge, to any person obtaining a copy
   7 * of this software and associated documentation files (the "Software"), to deal
   8 * in the Software without restriction, including without limitation the rights
   9 * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
  10 * copies of the Software, and to permit persons to whom the Software is
  11 * furnished to do so, subject to the following conditions:
  12 *
  13 * The above copyright notice and this permission notice shall be included in
  14 * all copies or substantial portions of the Software.
  15 *
  16 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
  17 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
  18 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
  19 * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
  20 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
  21 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
  22 * THE SOFTWARE.
  23 */
  24
  25#include "qemu/osdep.h"
  26#include <alsa/asoundlib.h>
  27#include "qemu/main-loop.h"
  28#include "qemu/module.h"
  29#include "audio.h"
  30#include "trace.h"
  31
  32#pragma GCC diagnostic ignored "-Waddress"
  33
  34#define AUDIO_CAP "alsa"
  35#include "audio_int.h"
  36
  37#define DEBUG_ALSA 0
  38
  39struct pollhlp {
  40    snd_pcm_t *handle;
  41    struct pollfd *pfds;
  42    int count;
  43    int mask;
  44    AudioState *s;
  45};
  46
  47typedef struct ALSAVoiceOut {
  48    HWVoiceOut hw;
  49    snd_pcm_t *handle;
  50    struct pollhlp pollhlp;
  51    Audiodev *dev;
  52} ALSAVoiceOut;
  53
  54typedef struct ALSAVoiceIn {
  55    HWVoiceIn hw;
  56    snd_pcm_t *handle;
  57    struct pollhlp pollhlp;
  58    Audiodev *dev;
  59} ALSAVoiceIn;
  60
  61struct alsa_params_req {
  62    int freq;
  63    snd_pcm_format_t fmt;
  64    int nchannels;
  65};
  66
  67struct alsa_params_obt {
  68    int freq;
  69    AudioFormat fmt;
  70    int endianness;
  71    int nchannels;
  72    snd_pcm_uframes_t samples;
  73};
  74
  75static void GCC_FMT_ATTR (2, 3) alsa_logerr (int err, const char *fmt, ...)
  76{
  77    va_list ap;
  78
  79    va_start (ap, fmt);
  80    AUD_vlog (AUDIO_CAP, fmt, ap);
  81    va_end (ap);
  82
  83    AUD_log (AUDIO_CAP, "Reason: %s\n", snd_strerror (err));
  84}
  85
  86static void GCC_FMT_ATTR (3, 4) alsa_logerr2 (
  87    int err,
  88    const char *typ,
  89    const char *fmt,
  90    ...
  91    )
  92{
  93    va_list ap;
  94
  95    AUD_log (AUDIO_CAP, "Could not initialize %s\n", typ);
  96
  97    va_start (ap, fmt);
  98    AUD_vlog (AUDIO_CAP, fmt, ap);
  99    va_end (ap);
 100
 101    AUD_log (AUDIO_CAP, "Reason: %s\n", snd_strerror (err));
 102}
 103
 104static void alsa_fini_poll (struct pollhlp *hlp)
 105{
 106    int i;
 107    struct pollfd *pfds = hlp->pfds;
 108
 109    if (pfds) {
 110        for (i = 0; i < hlp->count; ++i) {
 111            qemu_set_fd_handler (pfds[i].fd, NULL, NULL, NULL);
 112        }
 113        g_free (pfds);
 114    }
 115    hlp->pfds = NULL;
 116    hlp->count = 0;
 117    hlp->handle = NULL;
 118}
 119
 120static void alsa_anal_close1 (snd_pcm_t **handlep)
 121{
 122    int err = snd_pcm_close (*handlep);
 123    if (err) {
 124        alsa_logerr (err, "Failed to close PCM handle %p\n", *handlep);
 125    }
 126    *handlep = NULL;
 127}
 128
 129static void alsa_anal_close (snd_pcm_t **handlep, struct pollhlp *hlp)
 130{
 131    alsa_fini_poll (hlp);
 132    alsa_anal_close1 (handlep);
 133}
 134
 135static int alsa_recover (snd_pcm_t *handle)
 136{
 137    int err = snd_pcm_prepare (handle);
 138    if (err < 0) {
 139        alsa_logerr (err, "Failed to prepare handle %p\n", handle);
 140        return -1;
 141    }
 142    return 0;
 143}
 144
 145static int alsa_resume (snd_pcm_t *handle)
 146{
 147    int err = snd_pcm_resume (handle);
 148    if (err < 0) {
 149        alsa_logerr (err, "Failed to resume handle %p\n", handle);
 150        return -1;
 151    }
 152    return 0;
 153}
 154
 155static void alsa_poll_handler (void *opaque)
 156{
 157    int err, count;
 158    snd_pcm_state_t state;
 159    struct pollhlp *hlp = opaque;
 160    unsigned short revents;
 161
 162    count = poll (hlp->pfds, hlp->count, 0);
 163    if (count < 0) {
 164        dolog ("alsa_poll_handler: poll %s\n", strerror (errno));
 165        return;
 166    }
 167
 168    if (!count) {
 169        return;
 170    }
 171
 172    /* XXX: ALSA example uses initial count, not the one returned by
 173       poll, correct? */
 174    err = snd_pcm_poll_descriptors_revents (hlp->handle, hlp->pfds,
 175                                            hlp->count, &revents);
 176    if (err < 0) {
 177        alsa_logerr (err, "snd_pcm_poll_descriptors_revents");
 178        return;
 179    }
 180
 181    if (!(revents & hlp->mask)) {
 182        trace_alsa_revents(revents);
 183        return;
 184    }
 185
 186    state = snd_pcm_state (hlp->handle);
 187    switch (state) {
 188    case SND_PCM_STATE_SETUP:
 189        alsa_recover (hlp->handle);
 190        break;
 191
 192    case SND_PCM_STATE_XRUN:
 193        alsa_recover (hlp->handle);
 194        break;
 195
 196    case SND_PCM_STATE_SUSPENDED:
 197        alsa_resume (hlp->handle);
 198        break;
 199
 200    case SND_PCM_STATE_PREPARED:
 201        audio_run(hlp->s, "alsa run (prepared)");
 202        break;
 203
 204    case SND_PCM_STATE_RUNNING:
 205        audio_run(hlp->s, "alsa run (running)");
 206        break;
 207
 208    default:
 209        dolog ("Unexpected state %d\n", state);
 210    }
 211}
 212
 213static int alsa_poll_helper (snd_pcm_t *handle, struct pollhlp *hlp, int mask)
 214{
 215    int i, count, err;
 216    struct pollfd *pfds;
 217
 218    count = snd_pcm_poll_descriptors_count (handle);
 219    if (count <= 0) {
 220        dolog ("Could not initialize poll mode\n"
 221               "Invalid number of poll descriptors %d\n", count);
 222        return -1;
 223    }
 224
 225    pfds = audio_calloc ("alsa_poll_helper", count, sizeof (*pfds));
 226    if (!pfds) {
 227        dolog ("Could not initialize poll mode\n");
 228        return -1;
 229    }
 230
 231    err = snd_pcm_poll_descriptors (handle, pfds, count);
 232    if (err < 0) {
 233        alsa_logerr (err, "Could not initialize poll mode\n"
 234                     "Could not obtain poll descriptors\n");
 235        g_free (pfds);
 236        return -1;
 237    }
 238
 239    for (i = 0; i < count; ++i) {
 240        if (pfds[i].events & POLLIN) {
 241            qemu_set_fd_handler (pfds[i].fd, alsa_poll_handler, NULL, hlp);
 242        }
 243        if (pfds[i].events & POLLOUT) {
 244            trace_alsa_pollout(i, pfds[i].fd);
 245            qemu_set_fd_handler (pfds[i].fd, NULL, alsa_poll_handler, hlp);
 246        }
 247        trace_alsa_set_handler(pfds[i].events, i, pfds[i].fd, err);
 248
 249    }
 250    hlp->pfds = pfds;
 251    hlp->count = count;
 252    hlp->handle = handle;
 253    hlp->mask = mask;
 254    return 0;
 255}
 256
 257static int alsa_poll_out (HWVoiceOut *hw)
 258{
 259    ALSAVoiceOut *alsa = (ALSAVoiceOut *) hw;
 260
 261    return alsa_poll_helper (alsa->handle, &alsa->pollhlp, POLLOUT);
 262}
 263
 264static int alsa_poll_in (HWVoiceIn *hw)
 265{
 266    ALSAVoiceIn *alsa = (ALSAVoiceIn *) hw;
 267
 268    return alsa_poll_helper (alsa->handle, &alsa->pollhlp, POLLIN);
 269}
 270
 271static snd_pcm_format_t aud_to_alsafmt (AudioFormat fmt, int endianness)
 272{
 273    switch (fmt) {
 274    case AUDIO_FORMAT_S8:
 275        return SND_PCM_FORMAT_S8;
 276
 277    case AUDIO_FORMAT_U8:
 278        return SND_PCM_FORMAT_U8;
 279
 280    case AUDIO_FORMAT_S16:
 281        if (endianness) {
 282            return SND_PCM_FORMAT_S16_BE;
 283        } else {
 284            return SND_PCM_FORMAT_S16_LE;
 285        }
 286
 287    case AUDIO_FORMAT_U16:
 288        if (endianness) {
 289            return SND_PCM_FORMAT_U16_BE;
 290        } else {
 291            return SND_PCM_FORMAT_U16_LE;
 292        }
 293
 294    case AUDIO_FORMAT_S32:
 295        if (endianness) {
 296            return SND_PCM_FORMAT_S32_BE;
 297        } else {
 298            return SND_PCM_FORMAT_S32_LE;
 299        }
 300
 301    case AUDIO_FORMAT_U32:
 302        if (endianness) {
 303            return SND_PCM_FORMAT_U32_BE;
 304        } else {
 305            return SND_PCM_FORMAT_U32_LE;
 306        }
 307
 308    case AUDIO_FORMAT_F32:
 309        if (endianness) {
 310            return SND_PCM_FORMAT_FLOAT_BE;
 311        } else {
 312            return SND_PCM_FORMAT_FLOAT_LE;
 313        }
 314
 315    default:
 316        dolog ("Internal logic error: Bad audio format %d\n", fmt);
 317#ifdef DEBUG_AUDIO
 318        abort ();
 319#endif
 320        return SND_PCM_FORMAT_U8;
 321    }
 322}
 323
 324static int alsa_to_audfmt (snd_pcm_format_t alsafmt, AudioFormat *fmt,
 325                           int *endianness)
 326{
 327    switch (alsafmt) {
 328    case SND_PCM_FORMAT_S8:
 329        *endianness = 0;
 330        *fmt = AUDIO_FORMAT_S8;
 331        break;
 332
 333    case SND_PCM_FORMAT_U8:
 334        *endianness = 0;
 335        *fmt = AUDIO_FORMAT_U8;
 336        break;
 337
 338    case SND_PCM_FORMAT_S16_LE:
 339        *endianness = 0;
 340        *fmt = AUDIO_FORMAT_S16;
 341        break;
 342
 343    case SND_PCM_FORMAT_U16_LE:
 344        *endianness = 0;
 345        *fmt = AUDIO_FORMAT_U16;
 346        break;
 347
 348    case SND_PCM_FORMAT_S16_BE:
 349        *endianness = 1;
 350        *fmt = AUDIO_FORMAT_S16;
 351        break;
 352
 353    case SND_PCM_FORMAT_U16_BE:
 354        *endianness = 1;
 355        *fmt = AUDIO_FORMAT_U16;
 356        break;
 357
 358    case SND_PCM_FORMAT_S32_LE:
 359        *endianness = 0;
 360        *fmt = AUDIO_FORMAT_S32;
 361        break;
 362
 363    case SND_PCM_FORMAT_U32_LE:
 364        *endianness = 0;
 365        *fmt = AUDIO_FORMAT_U32;
 366        break;
 367
 368    case SND_PCM_FORMAT_S32_BE:
 369        *endianness = 1;
 370        *fmt = AUDIO_FORMAT_S32;
 371        break;
 372
 373    case SND_PCM_FORMAT_U32_BE:
 374        *endianness = 1;
 375        *fmt = AUDIO_FORMAT_U32;
 376        break;
 377
 378    case SND_PCM_FORMAT_FLOAT_LE:
 379        *endianness = 0;
 380        *fmt = AUDIO_FORMAT_F32;
 381        break;
 382
 383    case SND_PCM_FORMAT_FLOAT_BE:
 384        *endianness = 1;
 385        *fmt = AUDIO_FORMAT_F32;
 386        break;
 387
 388    default:
 389        dolog ("Unrecognized audio format %d\n", alsafmt);
 390        return -1;
 391    }
 392
 393    return 0;
 394}
 395
 396static void alsa_dump_info (struct alsa_params_req *req,
 397                            struct alsa_params_obt *obt,
 398                            snd_pcm_format_t obtfmt,
 399                            AudiodevAlsaPerDirectionOptions *apdo)
 400{
 401    dolog("parameter | requested value | obtained value\n");
 402    dolog("format    |      %10d |     %10d\n", req->fmt, obtfmt);
 403    dolog("channels  |      %10d |     %10d\n",
 404          req->nchannels, obt->nchannels);
 405    dolog("frequency |      %10d |     %10d\n", req->freq, obt->freq);
 406    dolog("============================================\n");
 407    dolog("requested: buffer len %" PRId32 " period len %" PRId32 "\n",
 408          apdo->buffer_length, apdo->period_length);
 409    dolog("obtained: samples %ld\n", obt->samples);
 410}
 411
 412static void alsa_set_threshold (snd_pcm_t *handle, snd_pcm_uframes_t threshold)
 413{
 414    int err;
 415    snd_pcm_sw_params_t *sw_params;
 416
 417    snd_pcm_sw_params_alloca (&sw_params);
 418
 419    err = snd_pcm_sw_params_current (handle, sw_params);
 420    if (err < 0) {
 421        dolog ("Could not fully initialize DAC\n");
 422        alsa_logerr (err, "Failed to get current software parameters\n");
 423        return;
 424    }
 425
 426    err = snd_pcm_sw_params_set_start_threshold (handle, sw_params, threshold);
 427    if (err < 0) {
 428        dolog ("Could not fully initialize DAC\n");
 429        alsa_logerr (err, "Failed to set software threshold to %ld\n",
 430                     threshold);
 431        return;
 432    }
 433
 434    err = snd_pcm_sw_params (handle, sw_params);
 435    if (err < 0) {
 436        dolog ("Could not fully initialize DAC\n");
 437        alsa_logerr (err, "Failed to set software parameters\n");
 438        return;
 439    }
 440}
 441
 442static int alsa_open(bool in, struct alsa_params_req *req,
 443                     struct alsa_params_obt *obt, snd_pcm_t **handlep,
 444                     Audiodev *dev)
 445{
 446    AudiodevAlsaOptions *aopts = &dev->u.alsa;
 447    AudiodevAlsaPerDirectionOptions *apdo = in ? aopts->in : aopts->out;
 448    snd_pcm_t *handle;
 449    snd_pcm_hw_params_t *hw_params;
 450    int err;
 451    unsigned int freq, nchannels;
 452    const char *pcm_name = apdo->has_dev ? apdo->dev : "default";
 453    snd_pcm_uframes_t obt_buffer_size;
 454    const char *typ = in ? "ADC" : "DAC";
 455    snd_pcm_format_t obtfmt;
 456
 457    freq = req->freq;
 458    nchannels = req->nchannels;
 459
 460    snd_pcm_hw_params_alloca (&hw_params);
 461
 462    err = snd_pcm_open (
 463        &handle,
 464        pcm_name,
 465        in ? SND_PCM_STREAM_CAPTURE : SND_PCM_STREAM_PLAYBACK,
 466        SND_PCM_NONBLOCK
 467        );
 468    if (err < 0) {
 469        alsa_logerr2 (err, typ, "Failed to open `%s':\n", pcm_name);
 470        return -1;
 471    }
 472
 473    err = snd_pcm_hw_params_any (handle, hw_params);
 474    if (err < 0) {
 475        alsa_logerr2 (err, typ, "Failed to initialize hardware parameters\n");
 476        goto err;
 477    }
 478
 479    err = snd_pcm_hw_params_set_access (
 480        handle,
 481        hw_params,
 482        SND_PCM_ACCESS_RW_INTERLEAVED
 483        );
 484    if (err < 0) {
 485        alsa_logerr2 (err, typ, "Failed to set access type\n");
 486        goto err;
 487    }
 488
 489    err = snd_pcm_hw_params_set_format (handle, hw_params, req->fmt);
 490    if (err < 0) {
 491        alsa_logerr2 (err, typ, "Failed to set format %d\n", req->fmt);
 492    }
 493
 494    err = snd_pcm_hw_params_set_rate_near (handle, hw_params, &freq, 0);
 495    if (err < 0) {
 496        alsa_logerr2 (err, typ, "Failed to set frequency %d\n", req->freq);
 497        goto err;
 498    }
 499
 500    err = snd_pcm_hw_params_set_channels_near (
 501        handle,
 502        hw_params,
 503        &nchannels
 504        );
 505    if (err < 0) {
 506        alsa_logerr2 (err, typ, "Failed to set number of channels %d\n",
 507                      req->nchannels);
 508        goto err;
 509    }
 510
 511    if (apdo->buffer_length) {
 512        int dir = 0;
 513        unsigned int btime = apdo->buffer_length;
 514
 515        err = snd_pcm_hw_params_set_buffer_time_near(
 516            handle, hw_params, &btime, &dir);
 517
 518        if (err < 0) {
 519            alsa_logerr2(err, typ, "Failed to set buffer time to %" PRId32 "\n",
 520                         apdo->buffer_length);
 521            goto err;
 522        }
 523
 524        if (apdo->has_buffer_length && btime != apdo->buffer_length) {
 525            dolog("Requested buffer time %" PRId32
 526                  " was rejected, using %u\n", apdo->buffer_length, btime);
 527        }
 528    }
 529
 530    if (apdo->period_length) {
 531        int dir = 0;
 532        unsigned int ptime = apdo->period_length;
 533
 534        err = snd_pcm_hw_params_set_period_time_near(handle, hw_params, &ptime,
 535                                                     &dir);
 536
 537        if (err < 0) {
 538            alsa_logerr2(err, typ, "Failed to set period time to %" PRId32 "\n",
 539                         apdo->period_length);
 540            goto err;
 541        }
 542
 543        if (apdo->has_period_length && ptime != apdo->period_length) {
 544            dolog("Requested period time %" PRId32 " was rejected, using %d\n",
 545                  apdo->period_length, ptime);
 546        }
 547    }
 548
 549    err = snd_pcm_hw_params (handle, hw_params);
 550    if (err < 0) {
 551        alsa_logerr2 (err, typ, "Failed to apply audio parameters\n");
 552        goto err;
 553    }
 554
 555    err = snd_pcm_hw_params_get_buffer_size (hw_params, &obt_buffer_size);
 556    if (err < 0) {
 557        alsa_logerr2 (err, typ, "Failed to get buffer size\n");
 558        goto err;
 559    }
 560
 561    err = snd_pcm_hw_params_get_format (hw_params, &obtfmt);
 562    if (err < 0) {
 563        alsa_logerr2 (err, typ, "Failed to get format\n");
 564        goto err;
 565    }
 566
 567    if (alsa_to_audfmt (obtfmt, &obt->fmt, &obt->endianness)) {
 568        dolog ("Invalid format was returned %d\n", obtfmt);
 569        goto err;
 570    }
 571
 572    err = snd_pcm_prepare (handle);
 573    if (err < 0) {
 574        alsa_logerr2 (err, typ, "Could not prepare handle %p\n", handle);
 575        goto err;
 576    }
 577
 578    if (!in && aopts->has_threshold && aopts->threshold) {
 579        struct audsettings as = { .freq = freq };
 580        alsa_set_threshold(
 581            handle,
 582            audio_buffer_frames(qapi_AudiodevAlsaPerDirectionOptions_base(apdo),
 583                                &as, aopts->threshold));
 584    }
 585
 586    obt->nchannels = nchannels;
 587    obt->freq = freq;
 588    obt->samples = obt_buffer_size;
 589
 590    *handlep = handle;
 591
 592    if (DEBUG_ALSA || obtfmt != req->fmt ||
 593        obt->nchannels != req->nchannels || obt->freq != req->freq) {
 594        dolog ("Audio parameters for %s\n", typ);
 595        alsa_dump_info(req, obt, obtfmt, apdo);
 596    }
 597
 598    return 0;
 599
 600 err:
 601    alsa_anal_close1 (&handle);
 602    return -1;
 603}
 604
 605static size_t alsa_write(HWVoiceOut *hw, void *buf, size_t len)
 606{
 607    ALSAVoiceOut *alsa = (ALSAVoiceOut *) hw;
 608    size_t pos = 0;
 609    size_t len_frames = len / hw->info.bytes_per_frame;
 610
 611    while (len_frames) {
 612        char *src = advance(buf, pos);
 613        snd_pcm_sframes_t written;
 614
 615        written = snd_pcm_writei(alsa->handle, src, len_frames);
 616
 617        if (written <= 0) {
 618            switch (written) {
 619            case 0:
 620                trace_alsa_wrote_zero(len_frames);
 621                return pos;
 622
 623            case -EPIPE:
 624                if (alsa_recover(alsa->handle)) {
 625                    alsa_logerr(written, "Failed to write %zu frames\n",
 626                                len_frames);
 627                    return pos;
 628                }
 629                trace_alsa_xrun_out();
 630                continue;
 631
 632            case -ESTRPIPE:
 633                /*
 634                 * stream is suspended and waiting for an application
 635                 * recovery
 636                 */
 637                if (alsa_resume(alsa->handle)) {
 638                    alsa_logerr(written, "Failed to write %zu frames\n",
 639                                len_frames);
 640                    return pos;
 641                }
 642                trace_alsa_resume_out();
 643                continue;
 644
 645            case -EAGAIN:
 646                return pos;
 647
 648            default:
 649                alsa_logerr(written, "Failed to write %zu frames from %p\n",
 650                            len, src);
 651                return pos;
 652            }
 653        }
 654
 655        pos += written * hw->info.bytes_per_frame;
 656        if (written < len_frames) {
 657            break;
 658        }
 659        len_frames -= written;
 660    }
 661
 662    return pos;
 663}
 664
 665static void alsa_fini_out (HWVoiceOut *hw)
 666{
 667    ALSAVoiceOut *alsa = (ALSAVoiceOut *) hw;
 668
 669    ldebug ("alsa_fini\n");
 670    alsa_anal_close (&alsa->handle, &alsa->pollhlp);
 671}
 672
 673static int alsa_init_out(HWVoiceOut *hw, struct audsettings *as,
 674                         void *drv_opaque)
 675{
 676    ALSAVoiceOut *alsa = (ALSAVoiceOut *) hw;
 677    struct alsa_params_req req;
 678    struct alsa_params_obt obt;
 679    snd_pcm_t *handle;
 680    struct audsettings obt_as;
 681    Audiodev *dev = drv_opaque;
 682
 683    req.fmt = aud_to_alsafmt (as->fmt, as->endianness);
 684    req.freq = as->freq;
 685    req.nchannels = as->nchannels;
 686
 687    if (alsa_open(0, &req, &obt, &handle, dev)) {
 688        return -1;
 689    }
 690
 691    obt_as.freq = obt.freq;
 692    obt_as.nchannels = obt.nchannels;
 693    obt_as.fmt = obt.fmt;
 694    obt_as.endianness = obt.endianness;
 695
 696    audio_pcm_init_info (&hw->info, &obt_as);
 697    hw->samples = obt.samples;
 698
 699    alsa->pollhlp.s = hw->s;
 700    alsa->handle = handle;
 701    alsa->dev = dev;
 702    return 0;
 703}
 704
 705#define VOICE_CTL_PAUSE 0
 706#define VOICE_CTL_PREPARE 1
 707#define VOICE_CTL_START 2
 708
 709static int alsa_voice_ctl (snd_pcm_t *handle, const char *typ, int ctl)
 710{
 711    int err;
 712
 713    if (ctl == VOICE_CTL_PAUSE) {
 714        err = snd_pcm_drop (handle);
 715        if (err < 0) {
 716            alsa_logerr (err, "Could not stop %s\n", typ);
 717            return -1;
 718        }
 719    } else {
 720        err = snd_pcm_prepare (handle);
 721        if (err < 0) {
 722            alsa_logerr (err, "Could not prepare handle for %s\n", typ);
 723            return -1;
 724        }
 725        if (ctl == VOICE_CTL_START) {
 726            err = snd_pcm_start(handle);
 727            if (err < 0) {
 728                alsa_logerr (err, "Could not start handle for %s\n", typ);
 729                return -1;
 730            }
 731        }
 732    }
 733
 734    return 0;
 735}
 736
 737static void alsa_enable_out(HWVoiceOut *hw, bool enable)
 738{
 739    ALSAVoiceOut *alsa = (ALSAVoiceOut *) hw;
 740    AudiodevAlsaPerDirectionOptions *apdo = alsa->dev->u.alsa.out;
 741
 742    if (enable) {
 743        bool poll_mode = apdo->try_poll;
 744
 745        ldebug("enabling voice\n");
 746        if (poll_mode && alsa_poll_out(hw)) {
 747            poll_mode = 0;
 748        }
 749        hw->poll_mode = poll_mode;
 750        alsa_voice_ctl(alsa->handle, "playback", VOICE_CTL_PREPARE);
 751    } else {
 752        ldebug("disabling voice\n");
 753        if (hw->poll_mode) {
 754            hw->poll_mode = 0;
 755            alsa_fini_poll(&alsa->pollhlp);
 756        }
 757        alsa_voice_ctl(alsa->handle, "playback", VOICE_CTL_PAUSE);
 758    }
 759}
 760
 761static int alsa_init_in(HWVoiceIn *hw, struct audsettings *as, void *drv_opaque)
 762{
 763    ALSAVoiceIn *alsa = (ALSAVoiceIn *) hw;
 764    struct alsa_params_req req;
 765    struct alsa_params_obt obt;
 766    snd_pcm_t *handle;
 767    struct audsettings obt_as;
 768    Audiodev *dev = drv_opaque;
 769
 770    req.fmt = aud_to_alsafmt (as->fmt, as->endianness);
 771    req.freq = as->freq;
 772    req.nchannels = as->nchannels;
 773
 774    if (alsa_open(1, &req, &obt, &handle, dev)) {
 775        return -1;
 776    }
 777
 778    obt_as.freq = obt.freq;
 779    obt_as.nchannels = obt.nchannels;
 780    obt_as.fmt = obt.fmt;
 781    obt_as.endianness = obt.endianness;
 782
 783    audio_pcm_init_info (&hw->info, &obt_as);
 784    hw->samples = obt.samples;
 785
 786    alsa->pollhlp.s = hw->s;
 787    alsa->handle = handle;
 788    alsa->dev = dev;
 789    return 0;
 790}
 791
 792static void alsa_fini_in (HWVoiceIn *hw)
 793{
 794    ALSAVoiceIn *alsa = (ALSAVoiceIn *) hw;
 795
 796    alsa_anal_close (&alsa->handle, &alsa->pollhlp);
 797}
 798
 799static size_t alsa_read(HWVoiceIn *hw, void *buf, size_t len)
 800{
 801    ALSAVoiceIn *alsa = (ALSAVoiceIn *) hw;
 802    size_t pos = 0;
 803
 804    while (len) {
 805        void *dst = advance(buf, pos);
 806        snd_pcm_sframes_t nread;
 807
 808        nread = snd_pcm_readi(
 809            alsa->handle, dst, len / hw->info.bytes_per_frame);
 810
 811        if (nread <= 0) {
 812            switch (nread) {
 813            case 0:
 814                trace_alsa_read_zero(len);
 815                return pos;
 816
 817            case -EPIPE:
 818                if (alsa_recover(alsa->handle)) {
 819                    alsa_logerr(nread, "Failed to read %zu frames\n", len);
 820                    return pos;
 821                }
 822                trace_alsa_xrun_in();
 823                continue;
 824
 825            case -EAGAIN:
 826                return pos;
 827
 828            default:
 829                alsa_logerr(nread, "Failed to read %zu frames to %p\n",
 830                            len, dst);
 831                return pos;
 832            }
 833        }
 834
 835        pos += nread * hw->info.bytes_per_frame;
 836        len -= nread * hw->info.bytes_per_frame;
 837    }
 838
 839    return pos;
 840}
 841
 842static void alsa_enable_in(HWVoiceIn *hw, bool enable)
 843{
 844    ALSAVoiceIn *alsa = (ALSAVoiceIn *) hw;
 845    AudiodevAlsaPerDirectionOptions *apdo = alsa->dev->u.alsa.in;
 846
 847    if (enable) {
 848        bool poll_mode = apdo->try_poll;
 849
 850        ldebug("enabling voice\n");
 851        if (poll_mode && alsa_poll_in(hw)) {
 852            poll_mode = 0;
 853        }
 854        hw->poll_mode = poll_mode;
 855
 856        alsa_voice_ctl(alsa->handle, "capture", VOICE_CTL_START);
 857    } else {
 858        ldebug ("disabling voice\n");
 859        if (hw->poll_mode) {
 860            hw->poll_mode = 0;
 861            alsa_fini_poll(&alsa->pollhlp);
 862        }
 863        alsa_voice_ctl(alsa->handle, "capture", VOICE_CTL_PAUSE);
 864    }
 865}
 866
 867static void alsa_init_per_direction(AudiodevAlsaPerDirectionOptions *apdo)
 868{
 869    if (!apdo->has_try_poll) {
 870        apdo->try_poll = true;
 871        apdo->has_try_poll = true;
 872    }
 873}
 874
 875static void *alsa_audio_init(Audiodev *dev)
 876{
 877    AudiodevAlsaOptions *aopts;
 878    assert(dev->driver == AUDIODEV_DRIVER_ALSA);
 879
 880    aopts = &dev->u.alsa;
 881    alsa_init_per_direction(aopts->in);
 882    alsa_init_per_direction(aopts->out);
 883
 884    /*
 885     * need to define them, as otherwise alsa produces no sound
 886     * doesn't set has_* so alsa_open can identify it wasn't set by the user
 887     */
 888    if (!dev->u.alsa.out->has_period_length) {
 889        /* 1024 frames assuming 44100Hz */
 890        dev->u.alsa.out->period_length = 1024 * 1000000 / 44100;
 891    }
 892    if (!dev->u.alsa.out->has_buffer_length) {
 893        /* 4096 frames assuming 44100Hz */
 894        dev->u.alsa.out->buffer_length = 4096ll * 1000000 / 44100;
 895    }
 896
 897    /*
 898     * OptsVisitor sets unspecified optional fields to zero, but do not depend
 899     * on it...
 900     */
 901    if (!dev->u.alsa.in->has_period_length) {
 902        dev->u.alsa.in->period_length = 0;
 903    }
 904    if (!dev->u.alsa.in->has_buffer_length) {
 905        dev->u.alsa.in->buffer_length = 0;
 906    }
 907
 908    return dev;
 909}
 910
 911static void alsa_audio_fini (void *opaque)
 912{
 913}
 914
 915static struct audio_pcm_ops alsa_pcm_ops = {
 916    .init_out = alsa_init_out,
 917    .fini_out = alsa_fini_out,
 918    .write    = alsa_write,
 919    .run_buffer_out = audio_generic_run_buffer_out,
 920    .enable_out = alsa_enable_out,
 921
 922    .init_in  = alsa_init_in,
 923    .fini_in  = alsa_fini_in,
 924    .read     = alsa_read,
 925    .run_buffer_in = audio_generic_run_buffer_in,
 926    .enable_in = alsa_enable_in,
 927};
 928
 929static struct audio_driver alsa_audio_driver = {
 930    .name           = "alsa",
 931    .descr          = "ALSA http://www.alsa-project.org",
 932    .init           = alsa_audio_init,
 933    .fini           = alsa_audio_fini,
 934    .pcm_ops        = &alsa_pcm_ops,
 935    .can_be_default = 1,
 936    .max_voices_out = INT_MAX,
 937    .max_voices_in  = INT_MAX,
 938    .voice_size_out = sizeof (ALSAVoiceOut),
 939    .voice_size_in  = sizeof (ALSAVoiceIn)
 940};
 941
 942static void register_audio_alsa(void)
 943{
 944    audio_driver_register(&alsa_audio_driver);
 945}
 946type_init(register_audio_alsa);
 947