audio.c

xen 3.2.2 源码

static void audio_timer (void *opaque)
{
    AudioState *s = opaque;

    audio_run_out (s);
    audio_run_in (s);
    audio_run_capture (s);

    qemu_mod_timer (s->ts, qemu_get_clock (vm_clock) + conf.period.ticks);
}

static struct audio_option audio_options[] = {
    /* DAC */
    {"DAC_FIXED_SETTINGS", AUD_OPT_BOOL, &conf.fixed_out.enabled,
     "Use fixed settings for host DAC", NULL, 0},

    {"DAC_FIXED_FREQ", AUD_OPT_INT, &conf.fixed_out.settings.freq,
     "Frequency for fixed host DAC", NULL, 0},

    {"DAC_FIXED_FMT", AUD_OPT_FMT, &conf.fixed_out.settings.fmt,
     "Format for fixed host DAC", NULL, 0},

    {"DAC_FIXED_CHANNELS", AUD_OPT_INT, &conf.fixed_out.settings.nchannels,
     "Number of channels for fixed DAC (1 - mono, 2 - stereo)", NULL, 0},

    {"DAC_VOICES", AUD_OPT_INT, &conf.fixed_out.nb_voices,
     "Number of voices for DAC", NULL, 0},

    /* ADC */
    {"ADC_FIXED_SETTINGS", AUD_OPT_BOOL, &conf.fixed_in.enabled,
     "Use fixed settings for host ADC", NULL, 0},

    {"ADC_FIXED_FREQ", AUD_OPT_INT, &conf.fixed_in.settings.freq,
     "Frequency for fixed host ADC", NULL, 0},

    {"ADC_FIXED_FMT", AUD_OPT_FMT, &conf.fixed_in.settings.fmt,
     "Format for fixed host ADC", NULL, 0},

    {"ADC_FIXED_CHANNELS", AUD_OPT_INT, &conf.fixed_in.settings.nchannels,
     "Number of channels for fixed ADC (1 - mono, 2 - stereo)", NULL, 0},

    {"ADC_VOICES", AUD_OPT_INT, &conf.fixed_in.nb_voices,
     "Number of voices for ADC", NULL, 0},

    /* Misc */
    {"TIMER_PERIOD", AUD_OPT_INT, &conf.period.hz,
     "Timer period in HZ (0 - use lowest possible)", NULL, 0},

    {"PLIVE", AUD_OPT_BOOL, &conf.plive,
     "(undocumented)", NULL, 0},

    {"LOG_TO_MONITOR", AUD_OPT_BOOL, &conf.log_to_monitor,
     "print logging messages to montior instead of stderr", NULL, 0},

    {NULL, 0, NULL, NULL, NULL, 0}
};

static void audio_pp_nb_voices (const char *typ, int nb)
{
    switch (nb) {
    case 0:
        printf ("Does not support %s\n", typ);
        break;
    case 1:
        printf ("One %s voice\n", typ);
        break;
    case INT_MAX:
        printf ("Theoretically supports many %s voices\n", typ);
        break;
    default:
        printf ("Theoretically supports upto %d %s voices\n", nb, typ);
        break;
    }

}

void AUD_help (void)
{
    size_t i;

    audio_process_options ("AUDIO", audio_options);
    for (i = 0; i < sizeof (drvtab) / sizeof (drvtab[0]); i++) {
        struct audio_driver *d = drvtab[i];
        if (d->options) {
            audio_process_options (d->name, d->options);
        }
    }

    printf ("Audio options:\n");
    audio_print_options ("AUDIO", audio_options);
    printf ("\n");

    printf ("Available drivers:\n");

    for (i = 0; i < sizeof (drvtab) / sizeof (drvtab[0]); i++) {
        struct audio_driver *d = drvtab[i];

        printf ("Name: %s\n", d->name);
        printf ("Description: %s\n", d->descr);

        audio_pp_nb_voices ("playback", d->max_voices_out);
        audio_pp_nb_voices ("capture", d->max_voices_in);

        if (d->options) {
            printf ("Options:\n");
            audio_print_options (d->name, d->options);
        }
        else {
            printf ("No options\n");
        }
        printf ("\n");
    }

    printf (
        "Options are settable through environment variables.\n"
        "Example:\n"
#ifdef _WIN32
        "  set QEMU_AUDIO_DRV=wav\n"
        "  set QEMU_WAV_PATH=c:\\tune.wav\n"
#else
        "  export QEMU_AUDIO_DRV=wav\n"
        "  export QEMU_WAV_PATH=$HOME/tune.wav\n"
        "(for csh replace export with setenv in the above)\n"
#endif
        "  qemu ...\n\n"
        );
}

static int audio_driver_init (AudioState *s, struct audio_driver *drv)
{
    if (drv->options) {
        audio_process_options (drv->name, drv->options);
    }
    s->drv_opaque = drv->init ();

    if (s->drv_opaque) {
        audio_init_nb_voices_out (s, drv);
        audio_init_nb_voices_in (s, drv);
        s->drv = drv;
        return 0;
    }
    else {
        dolog ("Could not init `%s' audio driver\n", drv->name);
        return -1;
    }
}

static void audio_vm_change_state_handler (void *opaque, int running)
{
    AudioState *s = opaque;
    HWVoiceOut *hwo = NULL;
    HWVoiceIn *hwi = NULL;
    int op = running ? VOICE_ENABLE : VOICE_DISABLE;

    while ((hwo = audio_pcm_hw_find_any_enabled_out (s, hwo))) {
        hwo->pcm_ops->ctl_out (hwo, op);
    }

    while ((hwi = audio_pcm_hw_find_any_enabled_in (s, hwi))) {
        hwi->pcm_ops->ctl_in (hwi, op);
    }
}

static void audio_atexit (void)
{
    AudioState *s = &glob_audio_state;
    HWVoiceOut *hwo = NULL;
    HWVoiceIn *hwi = NULL;

    while ((hwo = audio_pcm_hw_find_any_enabled_out (s, hwo))) {
        SWVoiceCap *sc;

        hwo->pcm_ops->ctl_out (hwo, VOICE_DISABLE);
        hwo->pcm_ops->fini_out (hwo);

        for (sc = hwo->cap_head.lh_first; sc; sc = sc->entries.le_next) {
            CaptureVoiceOut *cap = sc->cap;
            struct capture_callback *cb;

            for (cb = cap->cb_head.lh_first; cb; cb = cb->entries.le_next) {
                cb->ops.destroy (cb->opaque);
            }
        }
    }

    while ((hwi = audio_pcm_hw_find_any_enabled_in (s, hwi))) {
        hwi->pcm_ops->ctl_in (hwi, VOICE_DISABLE);
        hwi->pcm_ops->fini_in (hwi);
    }

    if (s->drv) {
        s->drv->fini (s->drv_opaque);
    }
}

static void audio_save (QEMUFile *f, void *opaque)
{
    (void) f;
    (void) opaque;
}

static int audio_load (QEMUFile *f, void *opaque, int version_id)
{
    (void) f;
    (void) opaque;

    if (version_id != 1) {
        return -EINVAL;
    }

    return 0;
}

void AUD_register_card (AudioState *s, const char *name, QEMUSoundCard *card)
{
    card->audio = s;
    card->name = qemu_strdup (name);
    memset (&card->entries, 0, sizeof (card->entries));
    LIST_INSERT_HEAD (&s->card_head, card, entries);
}

void AUD_remove_card (QEMUSoundCard *card)
{
    LIST_REMOVE (card, entries);
    card->audio = NULL;
    qemu_free (card->name);
}

AudioState *AUD_init (void)
{
    size_t i;
    int done = 0;
    const char *drvname;
    AudioState *s = &glob_audio_state;

    LIST_INIT (&s->hw_head_out);
    LIST_INIT (&s->hw_head_in);
    LIST_INIT (&s->cap_head);
    atexit (audio_atexit);

    s->ts = qemu_new_timer (vm_clock, audio_timer, s);
    if (!s->ts) {
        dolog ("Could not create audio timer\n");
        return NULL;
    }

    audio_process_options ("AUDIO", audio_options);

    s->nb_hw_voices_out = conf.fixed_out.nb_voices;
    s->nb_hw_voices_in = conf.fixed_in.nb_voices;

    if (s->nb_hw_voices_out <= 0) {
        dolog ("Bogus number of playback voices %d, setting to 1\n",
               s->nb_hw_voices_out);
        s->nb_hw_voices_out = 1;
    }

    if (s->nb_hw_voices_in <= 0) {
        dolog ("Bogus number of capture voices %d, setting to 0\n",
               s->nb_hw_voices_in);
        s->nb_hw_voices_in = 0;
    }

    {
        int def;
        drvname = audio_get_conf_str ("QEMU_AUDIO_DRV", NULL, &def);
    }

    if (drvname) {
        int found = 0;

        for (i = 0; i < sizeof (drvtab) / sizeof (drvtab[0]); i++) {
            if (!strcmp (drvname, drvtab[i]->name)) {
                done = !audio_driver_init (s, drvtab[i]);
                found = 1;
                break;
            }
        }

        if (!found) {
            dolog ("Unknown audio driver `%s'\n", drvname);
            dolog ("Run with -audio-help to list available drivers\n");
        }
    }

    if (!done) {
        for (i = 0; !done && i < sizeof (drvtab) / sizeof (drvtab[0]); i++) {
            if (drvtab[i]->can_be_default) {
                done = !audio_driver_init (s, drvtab[i]);
            }
        }
    }

    if (!done) {
        done = !audio_driver_init (s, &no_audio_driver);
        if (!done) {
            dolog ("Could not initialize audio subsystem\n");
        }
        else {
            dolog ("warning: Using timer based audio emulation\n");
        }
    }

    if (done) {
        VMChangeStateEntry *e;

        if (conf.period.hz <= 0) {
            if (conf.period.hz < 0) {
                dolog ("warning: Timer period is negative - %d "
                       "treating as zero\n",
                       conf.period.hz);
            }
            conf.period.ticks = 1;
        }
        else {
            conf.period.ticks = ticks_per_sec / conf.period.hz;
        }

        e = qemu_add_vm_change_state_handler (audio_vm_change_state_handler, s);
        if (!e) {
            dolog ("warning: Could not register change state handler\n"
                   "(Audio can continue looping even after stopping the VM)\n");
        }
    }
    else {
        qemu_del_timer (s->ts);
        return NULL;
    }

    LIST_INIT (&s->card_head);
    register_savevm ("audio", 0, 1, audio_save, audio_load, s);
    qemu_mod_timer (s->ts, qemu_get_clock (vm_clock) + conf.period.ticks);
    return s;
}

CaptureVoiceOut *AUD_add_capture (
    AudioState *s,
    audsettings_t *as,
    struct audio_capture_ops *ops,
    void *cb_opaque
    )
{
    CaptureVoiceOut *cap;
    struct capture_callback *cb;

    if (!s) {
        /* XXX suppress */
        s = &glob_audio_state;
    }

    if (audio_validate_settings (as)) {
        dolog ("Invalid settings were passed when trying to add capture\n");
        audio_print_settings (as);
        goto err0;
    }

    cb = audio_calloc (AUDIO_FUNC, 1, sizeof (*cb));
    if (!cb) {
        dolog ("Could not allocate capture callback information, size %zu\n",
               sizeof (*cb));
        goto err0;
    }
    cb->ops = *ops;
    cb->opaque = cb_opaque;

    cap = audio_pcm_capture_find_specific (s, as);
    if (cap) {
        LIST_INSERT_HEAD (&cap->cb_head, cb, entries);
        return cap;
    }
    else {
        HWVoiceOut *hw;
        CaptureVoiceOut *cap;

        cap = audio_calloc (AUDIO_FUNC, 1, sizeof (*cap));
        if (!cap) {
            dolog ("Could not allocate capture voice, size %zu\n",
                   sizeof (*cap));
            goto err1;
        }

        hw = &cap->hw;
        LIST_INIT (&hw->sw_head);
        LIST_INIT (&cap->cb_head);

        /* XXX find a more elegant way */
        hw->samples = 4096 * 4;
        hw->mix_buf = audio_calloc (AUDIO_FUNC, hw->samples,
                                    sizeof (st_sample_t));
        if (!hw->mix_buf) {
            dolog ("Could not allocate capture mix buffer (%d samples)\n",
                   hw->samples);
            goto err2;
        }

        audio_pcm_init_info (&hw->info, as);

        cap->buf = audio_calloc (AUDIO_FUNC, hw->samples, 1 << hw->info.shift);
        if (!cap->buf) {
            dolog ("Could not allocate capture buffer "
                   "(%d samples, each %d bytes)\n",
                   hw->samples, 1 << hw->info.shift);
            goto err3;
        }

        hw->clip = mixeng_clip
            [hw->info.nchannels == 2]
            [hw->info.sign]
            [hw->info.swap_endianness]
            [hw->info.bits == 16];

        LIST_INSERT_HEAD (&s->cap_head, cap, entries);
        LIST_INSERT_HEAD (&cap->cb_head, cb, entries);

        hw = NULL;
        while ((hw = audio_pcm_hw_find_any_out (s, hw))) {
            audio_attach_capture (s, hw);
        }
        return cap;

    err3:
        qemu_free (cap->hw.mix_buf);
    err2:
        qemu_free (cap);
    err1:
        qemu_free (cb);
    err0:
        return NULL;
    }
}

void AUD_del_capture (CaptureVoiceOut *cap, void *cb_opaque)
{
    struct capture_callback *cb;

    for (cb = cap->cb_head.lh_first; cb; cb = cb->entries.le_next) {
        if (cb->opaque == cb_opaque) {
            cb->ops.destroy (cb_opaque);
            LIST_REMOVE (cb, entries);
            qemu_free (cb);

            if (!cap->cb_head.lh_first) {
                SWVoiceOut *sw = cap->hw.sw_head.lh_first, *sw1;

                while (sw) {
                    SWVoiceCap *sc = (SWVoiceCap *) sw;
#ifdef DEBUG_CAPTURE
                    dolog ("freeing %s\n", sw->name);
#endif

                    sw1 = sw->entries.le_next;
                    if (sw->rate) {
                        st_rate_stop (sw->rate);
                        sw->rate = NULL;
                    }
                    LIST_REMOVE (sw, entries);
                    LIST_REMOVE (sc, entries);
                    qemu_free (sc);
                    sw = sw1;
                }
                LIST_REMOVE (cap, entries);
                qemu_free (cap);
            }
            return;
        }
    }
}