audio.c

qemu虚拟机代码

    if (!sw) {
        return 0;
    }

    live = sw->hw->total_samples_captured - sw->total_hw_samples_acquired;
    if (audio_bug (AUDIO_FUNC, live < 0 || live > sw->hw->samples)) {
        dolog ("live=%d sw->hw->samples=%d\n", live, sw->hw->samples);
        return 0;
    }

    ldebug (
        "%s: get_avail live %d ret %lld\n",
        SW_NAME (sw),
        live, (((int64_t) live << 32) / sw->ratio) << sw->info.shift
        );

    return (((int64_t) live << 32) / sw->ratio) << sw->info.shift;
}

static int audio_get_free (SWVoiceOut *sw)
{
    int live, dead;

    if (!sw) {
        return 0;
    }

    live = sw->total_hw_samples_mixed;

    if (audio_bug (AUDIO_FUNC, live < 0 || live > sw->hw->samples)) {
        dolog ("live=%d sw->hw->samples=%d\n", live, sw->hw->samples);
        return 0;
    }

    dead = sw->hw->samples - live;

#ifdef DEBUG_OUT
    dolog ("%s: get_free live %d dead %d ret %lld\n",
           SW_NAME (sw),
           live, dead, (((int64_t) dead << 32) / sw->ratio) << sw->info.shift);
#endif

    return (((int64_t) dead << 32) / sw->ratio) << sw->info.shift;
}

static void audio_run_out (AudioState *s)
{
    HWVoiceOut *hw = NULL;
    SWVoiceOut *sw;

    while ((hw = audio_pcm_hw_find_any_enabled_out (s, hw))) {
        int played;
        int live, free, nb_live, cleanup_required;

        live = audio_pcm_hw_get_live_out2 (hw, &nb_live);
        if (!nb_live) {
            live = 0;
        }

        if (audio_bug (AUDIO_FUNC, live < 0 || live > hw->samples)) {
            dolog ("live=%d hw->samples=%d\n", live, hw->samples);
            continue;
        }

        if (hw->pending_disable && !nb_live) {
#ifdef DEBUG_OUT
            dolog ("Disabling voice\n");
#endif
            hw->enabled = 0;
            hw->pending_disable = 0;
            hw->pcm_ops->ctl_out (hw, VOICE_DISABLE);
            continue;
        }

        if (!live) {
            for (sw = hw->sw_head.lh_first; sw; sw = sw->entries.le_next) {
                if (sw->active) {
                    free = audio_get_free (sw);
                    if (free > 0) {
                        sw->callback.fn (sw->callback.opaque, free);
                    }
                }
            }
            continue;
        }

        played = hw->pcm_ops->run_out (hw);
        if (audio_bug (AUDIO_FUNC, hw->rpos >= hw->samples)) {
            dolog ("hw->rpos=%d hw->samples=%d played=%d\n",
                   hw->rpos, hw->samples, played);
            hw->rpos = 0;
        }

#ifdef DEBUG_OUT
        dolog ("played=%d\n", played);
#endif

        if (played) {
            hw->ts_helper += played;
        }

        cleanup_required = 0;
        for (sw = hw->sw_head.lh_first; sw; sw = sw->entries.le_next) {
            if (!sw->active && sw->empty) {
                continue;
            }

            if (audio_bug (AUDIO_FUNC, played > sw->total_hw_samples_mixed)) {
                dolog ("played=%d sw->total_hw_samples_mixed=%d\n",
                       played, sw->total_hw_samples_mixed);
                played = sw->total_hw_samples_mixed;
            }

            sw->total_hw_samples_mixed -= played;

            if (!sw->total_hw_samples_mixed) {
                sw->empty = 1;
                cleanup_required |= !sw->active && !sw->callback.fn;
            }

            if (sw->active) {
                free = audio_get_free (sw);
                if (free > 0) {
                    sw->callback.fn (sw->callback.opaque, free);
                }
            }
        }

        if (cleanup_required) {
        restart:
            for (sw = hw->sw_head.lh_first; sw; sw = sw->entries.le_next) {
                if (!sw->active && !sw->callback.fn) {
#ifdef DEBUG_PLIVE
                    dolog ("Finishing with old voice\n");
#endif
                    audio_close_out (s, sw);
                    goto restart; /* play it safe */
                }
            }
        }
    }
}

static void audio_run_in (AudioState *s)
{
    HWVoiceIn *hw = NULL;

    while ((hw = audio_pcm_hw_find_any_enabled_in (s, hw))) {
        SWVoiceIn *sw;
        int captured, min;

        captured = hw->pcm_ops->run_in (hw);

        min = audio_pcm_hw_find_min_in (hw);
        hw->total_samples_captured += captured - min;
        hw->ts_helper += captured;

        for (sw = hw->sw_head.lh_first; sw; sw = sw->entries.le_next) {
            sw->total_hw_samples_acquired -= min;

            if (sw->active) {
                int avail;

                avail = audio_get_avail (sw);
                if (avail > 0) {
                    sw->callback.fn (sw->callback.opaque, avail);
                }
            }
        }
    }
}

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

    audio_run_out (s);
    audio_run_in (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))) {
        hwo->pcm_ops->ctl_out (hwo, VOICE_DISABLE);
        hwo->pcm_ops->fini_out (hwo);
    }

    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);
    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;
}