ossaudio.c

qemu虚拟机代码

    }
    if (oss->mmapped) {
        oss->old_optr = cntinfo.ptr;
    }

    hw->rpos = rpos;
    return decr;
}

static void oss_fini_out (HWVoiceOut *hw)
{
    int err;
    OSSVoiceOut *oss = (OSSVoiceOut *) hw;

    ldebug ("oss_fini\n");
    oss_anal_close (&oss->fd);

    if (oss->pcm_buf) {
        if (oss->mmapped) {
            err = munmap (oss->pcm_buf, hw->samples << hw->info.shift);
            if (err) {
                oss_logerr (errno, "Failed to unmap buffer %p, size %d\n",
                            oss->pcm_buf, hw->samples << hw->info.shift);
            }
        }
        else {
            qemu_free (oss->pcm_buf);
        }
        oss->pcm_buf = NULL;
    }
}

static int oss_init_out (HWVoiceOut *hw, audsettings_t *as)
{
    OSSVoiceOut *oss = (OSSVoiceOut *) hw;
    struct oss_params req, obt;
    int endianness;
    int err;
    int fd;
    audfmt_e effective_fmt;
    audsettings_t obt_as;

    oss->fd = -1;

    req.fmt = aud_to_ossfmt (as->fmt);
    req.freq = as->freq;
    req.nchannels = as->nchannels;
    req.fragsize = conf.fragsize;
    req.nfrags = conf.nfrags;

    if (oss_open (0, &req, &obt, &fd)) {
        return -1;
    }

    err = oss_to_audfmt (obt.fmt, &effective_fmt, &endianness);
    if (err) {
        oss_anal_close (&fd);
        return -1;
    }

    obt_as.freq = obt.freq;
    obt_as.nchannels = obt.nchannels;
    obt_as.fmt = effective_fmt;

    audio_pcm_init_info (
        &hw->info,
        &obt_as,
        audio_need_to_swap_endian (endianness)
        );
    oss->nfrags = obt.nfrags;
    oss->fragsize = obt.fragsize;

    if (obt.nfrags * obt.fragsize & hw->info.align) {
        dolog ("warning: Misaligned DAC buffer, size %d, alignment %d\n",
               obt.nfrags * obt.fragsize, hw->info.align + 1);
    }

    hw->samples = (obt.nfrags * obt.fragsize) >> hw->info.shift;

    oss->mmapped = 0;
    if (conf.try_mmap) {
        oss->pcm_buf = mmap (
            0,
            hw->samples << hw->info.shift,
            PROT_READ | PROT_WRITE,
            MAP_SHARED,
            fd,
            0
            );
        if (oss->pcm_buf == MAP_FAILED) {
            oss_logerr (errno, "Failed to map %d bytes of DAC\n",
                        hw->samples << hw->info.shift);
        } else {
            int err;
            int trig = 0;
            if (ioctl (fd, SNDCTL_DSP_SETTRIGGER, &trig) < 0) {
                oss_logerr (errno, "SNDCTL_DSP_SETTRIGGER 0 failed\n");
            }
            else {
                trig = PCM_ENABLE_OUTPUT;
                if (ioctl (fd, SNDCTL_DSP_SETTRIGGER, &trig) < 0) {
                    oss_logerr (
                        errno,
                        "SNDCTL_DSP_SETTRIGGER PCM_ENABLE_OUTPUT failed\n"
                        );
                }
                else {
                    oss->mmapped = 1;
                }
            }

            if (!oss->mmapped) {
                err = munmap (oss->pcm_buf, hw->samples << hw->info.shift);
                if (err) {
                    oss_logerr (errno, "Failed to unmap buffer %p size %d\n",
                                oss->pcm_buf, hw->samples << hw->info.shift);
                }
            }
        }
    }

    if (!oss->mmapped) {
        oss->pcm_buf = audio_calloc (
            AUDIO_FUNC,
            hw->samples,
            1 << hw->info.shift
            );
        if (!oss->pcm_buf) {
            dolog (
                "Could not allocate DAC buffer (%d samples, each %d bytes)\n",
                hw->samples,
                1 << hw->info.shift
                );
            oss_anal_close (&fd);
            return -1;
        }
    }

    oss->fd = fd;
    return 0;
}

static int oss_ctl_out (HWVoiceOut *hw, int cmd, ...)
{
    int trig;
    OSSVoiceOut *oss = (OSSVoiceOut *) hw;

    if (!oss->mmapped) {
        return 0;
    }

    switch (cmd) {
    case VOICE_ENABLE:
        ldebug ("enabling voice\n");
        audio_pcm_info_clear_buf (&hw->info, oss->pcm_buf, hw->samples);
        trig = PCM_ENABLE_OUTPUT;
        if (ioctl (oss->fd, SNDCTL_DSP_SETTRIGGER, &trig) < 0) {
            oss_logerr (
                errno,
                "SNDCTL_DSP_SETTRIGGER PCM_ENABLE_OUTPUT failed\n"
                );
            return -1;
        }
        break;

    case VOICE_DISABLE:
        ldebug ("disabling voice\n");
        trig = 0;
        if (ioctl (oss->fd, SNDCTL_DSP_SETTRIGGER, &trig) < 0) {
            oss_logerr (errno, "SNDCTL_DSP_SETTRIGGER 0 failed\n");
            return -1;
        }
        break;
    }
    return 0;
}

static int oss_init_in (HWVoiceIn *hw, audsettings_t *as)
{
    OSSVoiceIn *oss = (OSSVoiceIn *) hw;
    struct oss_params req, obt;
    int endianness;
    int err;
    int fd;
    audfmt_e effective_fmt;
    audsettings_t obt_as;

    oss->fd = -1;

    req.fmt = aud_to_ossfmt (as->fmt);
    req.freq = as->freq;
    req.nchannels = as->nchannels;
    req.fragsize = conf.fragsize;
    req.nfrags = conf.nfrags;
    if (oss_open (1, &req, &obt, &fd)) {
        return -1;
    }

    err = oss_to_audfmt (obt.fmt, &effective_fmt, &endianness);
    if (err) {
        oss_anal_close (&fd);
        return -1;
    }

    obt_as.freq = obt.freq;
    obt_as.nchannels = obt.nchannels;
    obt_as.fmt = effective_fmt;

    audio_pcm_init_info (
        &hw->info,
        &obt_as,
        audio_need_to_swap_endian (endianness)
        );
    oss->nfrags = obt.nfrags;
    oss->fragsize = obt.fragsize;

    if (obt.nfrags * obt.fragsize & hw->info.align) {
        dolog ("warning: Misaligned ADC buffer, size %d, alignment %d\n",
               obt.nfrags * obt.fragsize, hw->info.align + 1);
    }

    hw->samples = (obt.nfrags * obt.fragsize) >> hw->info.shift;
    oss->pcm_buf = audio_calloc (AUDIO_FUNC, hw->samples, 1 << hw->info.shift);
    if (!oss->pcm_buf) {
        dolog ("Could not allocate ADC buffer (%d samples, each %d bytes)\n",
               hw->samples, 1 << hw->info.shift);
        oss_anal_close (&fd);
        return -1;
    }

    oss->fd = fd;
    return 0;
}

static void oss_fini_in (HWVoiceIn *hw)
{
    OSSVoiceIn *oss = (OSSVoiceIn *) hw;

    oss_anal_close (&oss->fd);

    if (oss->pcm_buf) {
        qemu_free (oss->pcm_buf);
        oss->pcm_buf = NULL;
    }
}

static int oss_run_in (HWVoiceIn *hw)
{
    OSSVoiceIn *oss = (OSSVoiceIn *) hw;
    int hwshift = hw->info.shift;
    int i;
    int live = audio_pcm_hw_get_live_in (hw);
    int dead = hw->samples - live;
    size_t read_samples = 0;
    struct {
        int add;
        int len;
    } bufs[2] = {
        { hw->wpos, 0 },
        { 0, 0 }
    };

    if (!dead) {
        return 0;
    }

    if (hw->wpos + dead > hw->samples) {
        bufs[0].len = (hw->samples - hw->wpos) << hwshift;
        bufs[1].len = (dead - (hw->samples - hw->wpos)) << hwshift;
    }
    else {
        bufs[0].len = dead << hwshift;
    }


    for (i = 0; i < 2; ++i) {
        ssize_t nread;

        if (bufs[i].len) {
            void *p = advance (oss->pcm_buf, bufs[i].add << hwshift);
            nread = read (oss->fd, p, bufs[i].len);

            if (nread > 0) {
                if (nread & hw->info.align) {
                    dolog ("warning: Misaligned read %zd (requested %d), "
                           "alignment %d\n", nread, bufs[i].add << hwshift,
                           hw->info.align + 1);
                }
                read_samples += nread >> hwshift;
                hw->conv (hw->conv_buf + bufs[i].add, p, nread >> hwshift,
                          &nominal_volume);
            }

            if (bufs[i].len - nread) {
                if (nread == -1) {
                    switch (errno) {
                    case EINTR:
                    case EAGAIN:
                        break;
                    default:
                        oss_logerr (
                            errno,
                            "Failed to read %d bytes of audio (to %p)\n",
                            bufs[i].len, p
                            );
                        break;
                    }
                }
                break;
            }
        }
    }

    hw->wpos = (hw->wpos + read_samples) % hw->samples;
    return read_samples;
}

static int oss_read (SWVoiceIn *sw, void *buf, int size)
{
    return audio_pcm_sw_read (sw, buf, size);
}

static int oss_ctl_in (HWVoiceIn *hw, int cmd, ...)
{
    (void) hw;
    (void) cmd;
    return 0;
}

static void *oss_audio_init (void)
{
    return &conf;
}

static void oss_audio_fini (void *opaque)
{
    (void) opaque;
}

static struct audio_option oss_options[] = {
    {"FRAGSIZE", AUD_OPT_INT, &conf.fragsize,
     "Fragment size in bytes", NULL, 0},
    {"NFRAGS", AUD_OPT_INT, &conf.nfrags,
     "Number of fragments", NULL, 0},
    {"MMAP", AUD_OPT_BOOL, &conf.try_mmap,
     "Try using memory mapped access", NULL, 0},
    {"DAC_DEV", AUD_OPT_STR, &conf.devpath_out,
     "Path to DAC device", NULL, 0},
    {"ADC_DEV", AUD_OPT_STR, &conf.devpath_in,
     "Path to ADC device", NULL, 0},
    {NULL, 0, NULL, NULL, NULL, 0}
};

static struct audio_pcm_ops oss_pcm_ops = {
    oss_init_out,
    oss_fini_out,
    oss_run_out,
    oss_write,
    oss_ctl_out,

    oss_init_in,
    oss_fini_in,
    oss_run_in,
    oss_read,
    oss_ctl_in
};

struct audio_driver oss_audio_driver = {
    INIT_FIELD (name           = ) "oss",
    INIT_FIELD (descr          = ) "OSS http://www.opensound.com",
    INIT_FIELD (options        = ) oss_options,
    INIT_FIELD (init           = ) oss_audio_init,
    INIT_FIELD (fini           = ) oss_audio_fini,
    INIT_FIELD (pcm_ops        = ) &oss_pcm_ops,
    INIT_FIELD (can_be_default = ) 1,
    INIT_FIELD (max_voices_out = ) INT_MAX,
    INIT_FIELD (max_voices_in  = ) INT_MAX,
    INIT_FIELD (voice_size_out = ) sizeof (OSSVoiceOut),
    INIT_FIELD (voice_size_in  = ) sizeof (OSSVoiceIn)
};