Introduce Virtio-loopback epsilon release:

Epsilon release introduces a new compatibility layer which make virtio-loopback
design to work with QEMU and rust-vmm vhost-user backend without require any
changes.

Signed-off-by: Timos Ampelikiotis <t.ampelikiotis@virtualopensystems.com>
Change-Id: I52e57563e08a7d0bdc002f8e928ee61ba0c53dd9

1 files changed, 933 insertions, 0 deletions

diff --git a/audio/paaudio.c b/audio/paaudio.c
new file mode 100644
index 000000000..75401d539
--- /dev/null
+++ b/audio/paaudio.c
@@ -0,0 +1,933 @@
+/* public domain */
+
+#include "qemu/osdep.h"
+#include "qemu/module.h"
+#include "audio.h"
+#include "qapi/opts-visitor.h"
+
+#include <pulse/pulseaudio.h>
+
+#define AUDIO_CAP "pulseaudio"
+#include "audio_int.h"
+
+typedef struct PAConnection {
+    char *server;
+    int refcount;
+    QTAILQ_ENTRY(PAConnection) list;
+
+    pa_threaded_mainloop *mainloop;
+    pa_context *context;
+} PAConnection;
+
+static QTAILQ_HEAD(PAConnectionHead, PAConnection) pa_conns =
+    QTAILQ_HEAD_INITIALIZER(pa_conns);
+
+typedef struct {
+    Audiodev *dev;
+    PAConnection *conn;
+} paaudio;
+
+typedef struct {
+    HWVoiceOut hw;
+    pa_stream *stream;
+    paaudio *g;
+} PAVoiceOut;
+
+typedef struct {
+    HWVoiceIn hw;
+    pa_stream *stream;
+    const void *read_data;
+    size_t read_length;
+    paaudio *g;
+} PAVoiceIn;
+
+static void qpa_conn_fini(PAConnection *c);
+
+static void GCC_FMT_ATTR (2, 3) qpa_logerr (int err, const char *fmt, ...)
+{
+    va_list ap;
+
+    va_start (ap, fmt);
+    AUD_vlog (AUDIO_CAP, fmt, ap);
+    va_end (ap);
+
+    AUD_log (AUDIO_CAP, "Reason: %s\n", pa_strerror (err));
+}
+
+#ifndef PA_CONTEXT_IS_GOOD
+static inline int PA_CONTEXT_IS_GOOD(pa_context_state_t x)
+{
+    return
+        x == PA_CONTEXT_CONNECTING ||
+        x == PA_CONTEXT_AUTHORIZING ||
+        x == PA_CONTEXT_SETTING_NAME ||
+        x == PA_CONTEXT_READY;
+}
+#endif
+
+#ifndef PA_STREAM_IS_GOOD
+static inline int PA_STREAM_IS_GOOD(pa_stream_state_t x)
+{
+    return
+        x == PA_STREAM_CREATING ||
+        x == PA_STREAM_READY;
+}
+#endif
+
+#define CHECK_SUCCESS_GOTO(c, expression, label, msg)           \
+    do {                                                        \
+        if (!(expression)) {                                    \
+            qpa_logerr(pa_context_errno((c)->context), msg);    \
+            goto label;                                         \
+        }                                                       \
+    } while (0)
+
+#define CHECK_DEAD_GOTO(c, stream, label, msg)                          \
+    do {                                                                \
+        if (!(c)->context || !PA_CONTEXT_IS_GOOD (pa_context_get_state((c)->context)) || \
+            !(stream) || !PA_STREAM_IS_GOOD (pa_stream_get_state ((stream)))) { \
+            if (((c)->context && pa_context_get_state ((c)->context) == PA_CONTEXT_FAILED) || \
+                ((stream) && pa_stream_get_state ((stream)) == PA_STREAM_FAILED)) { \
+                qpa_logerr(pa_context_errno((c)->context), msg);        \
+            } else {                                                    \
+                qpa_logerr(PA_ERR_BADSTATE, msg);                       \
+            }                                                           \
+            goto label;                                                 \
+        }                                                               \
+    } while (0)
+
+static void *qpa_get_buffer_in(HWVoiceIn *hw, size_t *size)
+{
+    PAVoiceIn *p = (PAVoiceIn *) hw;
+    PAConnection *c = p->g->conn;
+    int r;
+
+    pa_threaded_mainloop_lock(c->mainloop);
+
+    CHECK_DEAD_GOTO(c, p->stream, unlock_and_fail,
+                    "pa_threaded_mainloop_lock failed\n");
+
+    if (!p->read_length) {
+        r = pa_stream_peek(p->stream, &p->read_data, &p->read_length);
+        CHECK_SUCCESS_GOTO(c, r == 0, unlock_and_fail,
+                           "pa_stream_peek failed\n");
+    }
+
+    *size = MIN(p->read_length, *size);
+
+    pa_threaded_mainloop_unlock(c->mainloop);
+    return (void *) p->read_data;
+
+unlock_and_fail:
+    pa_threaded_mainloop_unlock(c->mainloop);
+    *size = 0;
+    return NULL;
+}
+
+static void qpa_put_buffer_in(HWVoiceIn *hw, void *buf, size_t size)
+{
+    PAVoiceIn *p = (PAVoiceIn *) hw;
+    PAConnection *c = p->g->conn;
+    int r;
+
+    pa_threaded_mainloop_lock(c->mainloop);
+
+    CHECK_DEAD_GOTO(c, p->stream, unlock,
+                    "pa_threaded_mainloop_lock failed\n");
+
+    assert(buf == p->read_data && size <= p->read_length);
+
+    p->read_data += size;
+    p->read_length -= size;
+
+    if (size && !p->read_length) {
+        r = pa_stream_drop(p->stream);
+        CHECK_SUCCESS_GOTO(c, r == 0, unlock, "pa_stream_drop failed\n");
+    }
+
+unlock:
+    pa_threaded_mainloop_unlock(c->mainloop);
+}
+
+static size_t qpa_read(HWVoiceIn *hw, void *data, size_t length)
+{
+    PAVoiceIn *p = (PAVoiceIn *) hw;
+    PAConnection *c = p->g->conn;
+    size_t total = 0;
+
+    pa_threaded_mainloop_lock(c->mainloop);
+
+    CHECK_DEAD_GOTO(c, p->stream, unlock_and_fail,
+                    "pa_threaded_mainloop_lock failed\n");
+    if (pa_stream_get_state(p->stream) != PA_STREAM_READY) {
+        /* wait for stream to become ready */
+        goto unlock;
+    }
+
+    while (total < length) {
+        size_t l;
+        int r;
+
+        if (!p->read_length) {
+            r = pa_stream_peek(p->stream, &p->read_data, &p->read_length);
+            CHECK_SUCCESS_GOTO(c, r == 0, unlock_and_fail,
+                               "pa_stream_peek failed\n");
+            if (!p->read_length) {
+                /* buffer is empty */
+                break;
+            }
+        }
+
+        l = MIN(p->read_length, length - total);
+        memcpy((char *)data + total, p->read_data, l);
+
+        p->read_data += l;
+        p->read_length -= l;
+        total += l;
+
+        if (!p->read_length) {
+            r = pa_stream_drop(p->stream);
+            CHECK_SUCCESS_GOTO(c, r == 0, unlock_and_fail,
+                               "pa_stream_drop failed\n");
+        }
+    }
+
+unlock:
+    pa_threaded_mainloop_unlock(c->mainloop);
+    return total;
+
+unlock_and_fail:
+    pa_threaded_mainloop_unlock(c->mainloop);
+    return 0;
+}
+
+static void *qpa_get_buffer_out(HWVoiceOut *hw, size_t *size)
+{
+    PAVoiceOut *p = (PAVoiceOut *) hw;
+    PAConnection *c = p->g->conn;
+    void *ret;
+    size_t l;
+    int r;
+
+    pa_threaded_mainloop_lock(c->mainloop);
+
+    CHECK_DEAD_GOTO(c, p->stream, unlock_and_fail,
+                    "pa_threaded_mainloop_lock failed\n");
+    if (pa_stream_get_state(p->stream) != PA_STREAM_READY) {
+        /* wait for stream to become ready */
+        l = 0;
+        ret = NULL;
+        goto unlock;
+    }
+
+    l = pa_stream_writable_size(p->stream);
+    CHECK_SUCCESS_GOTO(c, l != (size_t) -1, unlock_and_fail,
+                       "pa_stream_writable_size failed\n");
+
+    *size = -1;
+    r = pa_stream_begin_write(p->stream, &ret, size);
+    CHECK_SUCCESS_GOTO(c, r >= 0, unlock_and_fail,
+                       "pa_stream_begin_write failed\n");
+
+unlock:
+    pa_threaded_mainloop_unlock(c->mainloop);
+    if (*size > l) {
+        *size = l;
+    }
+    return ret;
+
+unlock_and_fail:
+    pa_threaded_mainloop_unlock(c->mainloop);
+    *size = 0;
+    return NULL;
+}
+
+static size_t qpa_put_buffer_out(HWVoiceOut *hw, void *data, size_t length)
+{
+    PAVoiceOut *p = (PAVoiceOut *)hw;
+    PAConnection *c = p->g->conn;
+    int r;
+
+    pa_threaded_mainloop_lock(c->mainloop);
+
+    CHECK_DEAD_GOTO(c, p->stream, unlock_and_fail,
+                    "pa_threaded_mainloop_lock failed\n");
+
+    r = pa_stream_write(p->stream, data, length, NULL, 0LL, PA_SEEK_RELATIVE);
+    CHECK_SUCCESS_GOTO(c, r >= 0, unlock_and_fail, "pa_stream_write failed\n");
+
+    pa_threaded_mainloop_unlock(c->mainloop);
+    return length;
+
+unlock_and_fail:
+    pa_threaded_mainloop_unlock(c->mainloop);
+    return 0;
+}
+
+static size_t qpa_write(HWVoiceOut *hw, void *data, size_t length)
+{
+    PAVoiceOut *p = (PAVoiceOut *) hw;
+    PAConnection *c = p->g->conn;
+    size_t l;
+    int r;
+
+    pa_threaded_mainloop_lock(c->mainloop);
+
+    CHECK_DEAD_GOTO(c, p->stream, unlock_and_fail,
+                    "pa_threaded_mainloop_lock failed\n");
+    if (pa_stream_get_state(p->stream) != PA_STREAM_READY) {
+        /* wait for stream to become ready */
+        l = 0;
+        goto unlock;
+    }
+
+    l = pa_stream_writable_size(p->stream);
+
+    CHECK_SUCCESS_GOTO(c, l != (size_t) -1, unlock_and_fail,
+                       "pa_stream_writable_size failed\n");
+
+    if (l > length) {
+        l = length;
+    }
+
+    r = pa_stream_write(p->stream, data, l, NULL, 0LL, PA_SEEK_RELATIVE);
+    CHECK_SUCCESS_GOTO(c, r >= 0, unlock_and_fail, "pa_stream_write failed\n");
+
+unlock:
+    pa_threaded_mainloop_unlock(c->mainloop);
+    return l;
+
+unlock_and_fail:
+    pa_threaded_mainloop_unlock(c->mainloop);
+    return 0;
+}
+
+static pa_sample_format_t audfmt_to_pa (AudioFormat afmt, int endianness)
+{
+    int format;
+
+    switch (afmt) {
+    case AUDIO_FORMAT_S8:
+    case AUDIO_FORMAT_U8:
+        format = PA_SAMPLE_U8;
+        break;
+    case AUDIO_FORMAT_S16:
+    case AUDIO_FORMAT_U16:
+        format = endianness ? PA_SAMPLE_S16BE : PA_SAMPLE_S16LE;
+        break;
+    case AUDIO_FORMAT_S32:
+    case AUDIO_FORMAT_U32:
+        format = endianness ? PA_SAMPLE_S32BE : PA_SAMPLE_S32LE;
+        break;
+    case AUDIO_FORMAT_F32:
+        format = endianness ? PA_SAMPLE_FLOAT32BE : PA_SAMPLE_FLOAT32LE;
+        break;
+    default:
+        dolog ("Internal logic error: Bad audio format %d\n", afmt);
+        format = PA_SAMPLE_U8;
+        break;
+    }
+    return format;
+}
+
+static AudioFormat pa_to_audfmt (pa_sample_format_t fmt, int *endianness)
+{
+    switch (fmt) {
+    case PA_SAMPLE_U8:
+        return AUDIO_FORMAT_U8;
+    case PA_SAMPLE_S16BE:
+        *endianness = 1;
+        return AUDIO_FORMAT_S16;
+    case PA_SAMPLE_S16LE:
+        *endianness = 0;
+        return AUDIO_FORMAT_S16;
+    case PA_SAMPLE_S32BE:
+        *endianness = 1;
+        return AUDIO_FORMAT_S32;
+    case PA_SAMPLE_S32LE:
+        *endianness = 0;
+        return AUDIO_FORMAT_S32;
+    case PA_SAMPLE_FLOAT32BE:
+        *endianness = 1;
+        return AUDIO_FORMAT_F32;
+    case PA_SAMPLE_FLOAT32LE:
+        *endianness = 0;
+        return AUDIO_FORMAT_F32;
+    default:
+        dolog ("Internal logic error: Bad pa_sample_format %d\n", fmt);
+        return AUDIO_FORMAT_U8;
+    }
+}
+
+static void context_state_cb (pa_context *c, void *userdata)
+{
+    PAConnection *conn = userdata;
+
+    switch (pa_context_get_state(c)) {
+    case PA_CONTEXT_READY:
+    case PA_CONTEXT_TERMINATED:
+    case PA_CONTEXT_FAILED:
+        pa_threaded_mainloop_signal(conn->mainloop, 0);
+        break;
+
+    case PA_CONTEXT_UNCONNECTED:
+    case PA_CONTEXT_CONNECTING:
+    case PA_CONTEXT_AUTHORIZING:
+    case PA_CONTEXT_SETTING_NAME:
+        break;
+    }
+}
+
+static void stream_state_cb (pa_stream *s, void * userdata)
+{
+    PAConnection *c = userdata;
+
+    switch (pa_stream_get_state (s)) {
+
+    case PA_STREAM_READY:
+    case PA_STREAM_FAILED:
+    case PA_STREAM_TERMINATED:
+        pa_threaded_mainloop_signal(c->mainloop, 0);
+        break;
+
+    case PA_STREAM_UNCONNECTED:
+    case PA_STREAM_CREATING:
+        break;
+    }
+}
+
+static pa_stream *qpa_simple_new (
+        PAConnection *c,
+        const char *name,
+        pa_stream_direction_t dir,
+        const char *dev,
+        const pa_sample_spec *ss,
+        const pa_buffer_attr *attr,
+        int *rerror)
+{
+    int r;
+    pa_stream *stream = NULL;
+    pa_stream_flags_t flags;
+    pa_channel_map map;
+
+    pa_threaded_mainloop_lock(c->mainloop);
+
+    pa_channel_map_init(&map);
+    map.channels = ss->channels;
+
+    /*
+     * TODO: This currently expects the only frontend supporting more than 2
+     * channels is the usb-audio.  We will need some means to set channel
+     * order when a new frontend gains multi-channel support.
+     */
+    switch (ss->channels) {
+    case 1:
+        map.map[0] = PA_CHANNEL_POSITION_MONO;
+        break;
+
+    case 2:
+        map.map[0] = PA_CHANNEL_POSITION_LEFT;
+        map.map[1] = PA_CHANNEL_POSITION_RIGHT;
+        break;
+
+    case 6:
+        map.map[0] = PA_CHANNEL_POSITION_FRONT_LEFT;
+        map.map[1] = PA_CHANNEL_POSITION_FRONT_RIGHT;
+        map.map[2] = PA_CHANNEL_POSITION_CENTER;
+        map.map[3] = PA_CHANNEL_POSITION_LFE;
+        map.map[4] = PA_CHANNEL_POSITION_REAR_LEFT;
+        map.map[5] = PA_CHANNEL_POSITION_REAR_RIGHT;
+        break;
+
+    case 8:
+        map.map[0] = PA_CHANNEL_POSITION_FRONT_LEFT;
+        map.map[1] = PA_CHANNEL_POSITION_FRONT_RIGHT;
+        map.map[2] = PA_CHANNEL_POSITION_CENTER;
+        map.map[3] = PA_CHANNEL_POSITION_LFE;
+        map.map[4] = PA_CHANNEL_POSITION_REAR_LEFT;
+        map.map[5] = PA_CHANNEL_POSITION_REAR_RIGHT;
+        map.map[6] = PA_CHANNEL_POSITION_SIDE_LEFT;
+        map.map[7] = PA_CHANNEL_POSITION_SIDE_RIGHT;
+        break;
+
+    default:
+        dolog("Internal error: unsupported channel count %d\n", ss->channels);
+        goto fail;
+    }
+
+    stream = pa_stream_new(c->context, name, ss, &map);
+    if (!stream) {
+        goto fail;
+    }
+
+    pa_stream_set_state_callback(stream, stream_state_cb, c);
+
+    flags = PA_STREAM_EARLY_REQUESTS;
+
+    if (dev) {
+        /* don't move the stream if the user specified a sink/source */
+        flags |= PA_STREAM_DONT_MOVE;
+    }
+
+    if (dir == PA_STREAM_PLAYBACK) {
+        r = pa_stream_connect_playback(stream, dev, attr, flags, NULL, NULL);
+    } else {
+        r = pa_stream_connect_record(stream, dev, attr, flags);
+    }
+
+    if (r < 0) {
+        goto fail;
+    }
+
+    pa_threaded_mainloop_unlock(c->mainloop);
+
+    return stream;
+
+fail:
+    pa_threaded_mainloop_unlock(c->mainloop);
+
+    if (stream) {
+        pa_stream_unref (stream);
+    }
+
+    *rerror = pa_context_errno(c->context);
+
+    return NULL;
+}
+
+static int qpa_init_out(HWVoiceOut *hw, struct audsettings *as,
+                        void *drv_opaque)
+{
+    int error;
+    pa_sample_spec ss;
+    pa_buffer_attr ba;
+    struct audsettings obt_as = *as;
+    PAVoiceOut *pa = (PAVoiceOut *) hw;
+    paaudio *g = pa->g = drv_opaque;
+    AudiodevPaOptions *popts = &g->dev->u.pa;
+    AudiodevPaPerDirectionOptions *ppdo = popts->out;
+    PAConnection *c = g->conn;
+
+    ss.format = audfmt_to_pa (as->fmt, as->endianness);
+    ss.channels = as->nchannels;
+    ss.rate = as->freq;
+
+    ba.tlength = pa_usec_to_bytes(ppdo->latency, &ss);
+    ba.minreq = pa_usec_to_bytes(MIN(ppdo->latency >> 2,
+                                     (g->dev->timer_period >> 2) * 3), &ss);
+    ba.maxlength = -1;
+    ba.prebuf = -1;
+
+    obt_as.fmt = pa_to_audfmt (ss.format, &obt_as.endianness);
+
+    pa->stream = qpa_simple_new (
+        c,
+        ppdo->has_stream_name ? ppdo->stream_name : g->dev->id,
+        PA_STREAM_PLAYBACK,
+        ppdo->has_name ? ppdo->name : NULL,
+        &ss,
+        &ba,                    /* buffering attributes */
+        &error
+        );
+    if (!pa->stream) {
+        qpa_logerr (error, "pa_simple_new for playback failed\n");
+        goto fail1;
+    }
+
+    audio_pcm_init_info (&hw->info, &obt_as);
+    /*
+     * This is wrong. hw->samples counts in frames. hw->samples will be
+     * number of channels times larger than expected.
+     */
+    hw->samples = audio_buffer_samples(
+        qapi_AudiodevPaPerDirectionOptions_base(ppdo), &obt_as, 46440);
+
+    return 0;
+
+ fail1:
+    return -1;
+}
+
+static int qpa_init_in(HWVoiceIn *hw, struct audsettings *as, void *drv_opaque)
+{
+    int error;
+    pa_sample_spec ss;
+    pa_buffer_attr ba;
+    struct audsettings obt_as = *as;
+    PAVoiceIn *pa = (PAVoiceIn *) hw;
+    paaudio *g = pa->g = drv_opaque;
+    AudiodevPaOptions *popts = &g->dev->u.pa;
+    AudiodevPaPerDirectionOptions *ppdo = popts->in;
+    PAConnection *c = g->conn;
+
+    ss.format = audfmt_to_pa (as->fmt, as->endianness);
+    ss.channels = as->nchannels;
+    ss.rate = as->freq;
+
+    ba.fragsize = pa_usec_to_bytes((g->dev->timer_period >> 1) * 3, &ss);
+    ba.maxlength = pa_usec_to_bytes(
+        MAX(ppdo->latency, g->dev->timer_period * 3), &ss);
+    ba.minreq = -1;
+    ba.prebuf = -1;
+
+    obt_as.fmt = pa_to_audfmt (ss.format, &obt_as.endianness);
+
+    pa->stream = qpa_simple_new (
+        c,
+        ppdo->has_stream_name ? ppdo->stream_name : g->dev->id,
+        PA_STREAM_RECORD,
+        ppdo->has_name ? ppdo->name : NULL,
+        &ss,
+        &ba,                    /* buffering attributes */
+        &error
+        );
+    if (!pa->stream) {
+        qpa_logerr (error, "pa_simple_new for capture failed\n");
+        goto fail1;
+    }
+
+    audio_pcm_init_info (&hw->info, &obt_as);
+    /*
+     * This is wrong. hw->samples counts in frames. hw->samples will be
+     * number of channels times larger than expected.
+     */
+    hw->samples = audio_buffer_samples(
+        qapi_AudiodevPaPerDirectionOptions_base(ppdo), &obt_as, 46440);
+
+    return 0;
+
+ fail1:
+    return -1;
+}
+
+static void qpa_simple_disconnect(PAConnection *c, pa_stream *stream)
+{
+    int err;
+
+    /*
+     * wait until actually connects. workaround pa bug #247
+     * https://gitlab.freedesktop.org/pulseaudio/pulseaudio/issues/247
+     */
+    while (pa_stream_get_state(stream) == PA_STREAM_CREATING) {
+        pa_threaded_mainloop_wait(c->mainloop);
+    }
+
+    err = pa_stream_disconnect(stream);
+    if (err != 0) {
+        dolog("Failed to disconnect! err=%d\n", err);
+    }
+    pa_stream_unref(stream);
+}
+
+static void qpa_fini_out (HWVoiceOut *hw)
+{
+    PAVoiceOut *pa = (PAVoiceOut *) hw;
+
+    if (pa->stream) {
+        PAConnection *c = pa->g->conn;
+
+        pa_threaded_mainloop_lock(c->mainloop);
+        qpa_simple_disconnect(c, pa->stream);
+        pa->stream = NULL;
+        pa_threaded_mainloop_unlock(c->mainloop);
+    }
+}
+
+static void qpa_fini_in (HWVoiceIn *hw)
+{
+    PAVoiceIn *pa = (PAVoiceIn *) hw;
+
+    if (pa->stream) {
+        PAConnection *c = pa->g->conn;
+
+        pa_threaded_mainloop_lock(c->mainloop);
+        if (pa->read_length) {
+            int r = pa_stream_drop(pa->stream);
+            if (r) {
+                qpa_logerr(pa_context_errno(c->context),
+                           "pa_stream_drop failed\n");
+            }
+            pa->read_length = 0;
+        }
+        qpa_simple_disconnect(c, pa->stream);
+        pa->stream = NULL;
+        pa_threaded_mainloop_unlock(c->mainloop);
+    }
+}
+
+static void qpa_volume_out(HWVoiceOut *hw, Volume *vol)
+{
+    PAVoiceOut *pa = (PAVoiceOut *) hw;
+    pa_operation *op;
+    pa_cvolume v;
+    PAConnection *c = pa->g->conn;
+    int i;
+
+#ifdef PA_CHECK_VERSION    /* macro is present in 0.9.16+ */
+    pa_cvolume_init (&v);  /* function is present in 0.9.13+ */
+#endif
+
+    v.channels = vol->channels;
+    for (i = 0; i < vol->channels; ++i) {
+        v.values[i] = ((PA_VOLUME_NORM - PA_VOLUME_MUTED) * vol->vol[i]) / 255;
+    }
+
+    pa_threaded_mainloop_lock(c->mainloop);
+
+    op = pa_context_set_sink_input_volume(c->context,
+                                          pa_stream_get_index(pa->stream),
+                                          &v, NULL, NULL);
+    if (!op) {
+        qpa_logerr(pa_context_errno(c->context),
+                   "set_sink_input_volume() failed\n");
+    } else {
+        pa_operation_unref(op);
+    }
+
+    op = pa_context_set_sink_input_mute(c->context,
+                                        pa_stream_get_index(pa->stream),
+                                        vol->mute, NULL, NULL);
+    if (!op) {
+        qpa_logerr(pa_context_errno(c->context),
+                   "set_sink_input_mute() failed\n");
+    } else {
+        pa_operation_unref(op);
+    }
+
+    pa_threaded_mainloop_unlock(c->mainloop);
+}
+
+static void qpa_volume_in(HWVoiceIn *hw, Volume *vol)
+{
+    PAVoiceIn *pa = (PAVoiceIn *) hw;
+    pa_operation *op;
+    pa_cvolume v;
+    PAConnection *c = pa->g->conn;
+    int i;
+
+#ifdef PA_CHECK_VERSION
+    pa_cvolume_init (&v);
+#endif
+
+    v.channels = vol->channels;
+    for (i = 0; i < vol->channels; ++i) {
+        v.values[i] = ((PA_VOLUME_NORM - PA_VOLUME_MUTED) * vol->vol[i]) / 255;
+    }
+
+    pa_threaded_mainloop_lock(c->mainloop);
+
+    op = pa_context_set_source_output_volume(c->context,
+        pa_stream_get_index(pa->stream),
+        &v, NULL, NULL);
+    if (!op) {
+        qpa_logerr(pa_context_errno(c->context),
+                   "set_source_output_volume() failed\n");
+    } else {
+        pa_operation_unref(op);
+    }
+
+    op = pa_context_set_source_output_mute(c->context,
+        pa_stream_get_index(pa->stream),
+        vol->mute, NULL, NULL);
+    if (!op) {
+        qpa_logerr(pa_context_errno(c->context),
+                   "set_source_output_mute() failed\n");
+    } else {
+        pa_operation_unref(op);
+    }
+
+    pa_threaded_mainloop_unlock(c->mainloop);
+}
+
+static int qpa_validate_per_direction_opts(Audiodev *dev,
+                                           AudiodevPaPerDirectionOptions *pdo)
+{
+    if (!pdo->has_latency) {
+        pdo->has_latency = true;
+        pdo->latency = 15000;
+    }
+    return 1;
+}
+
+/* common */
+static void *qpa_conn_init(const char *server)
+{
+    PAConnection *c = g_malloc0(sizeof(PAConnection));
+    QTAILQ_INSERT_TAIL(&pa_conns, c, list);
+
+    c->mainloop = pa_threaded_mainloop_new();
+    if (!c->mainloop) {
+        goto fail;
+    }
+
+    c->context = pa_context_new(pa_threaded_mainloop_get_api(c->mainloop),
+                                audio_application_name());
+    if (!c->context) {
+        goto fail;
+    }
+
+    pa_context_set_state_callback(c->context, context_state_cb, c);
+
+    if (pa_context_connect(c->context, server, 0, NULL) < 0) {
+        qpa_logerr(pa_context_errno(c->context),
+                   "pa_context_connect() failed\n");
+        goto fail;
+    }
+
+    pa_threaded_mainloop_lock(c->mainloop);
+
+    if (pa_threaded_mainloop_start(c->mainloop) < 0) {
+        goto unlock_and_fail;
+    }
+
+    for (;;) {
+        pa_context_state_t state;
+
+        state = pa_context_get_state(c->context);
+
+        if (state == PA_CONTEXT_READY) {
+            break;
+        }
+
+        if (!PA_CONTEXT_IS_GOOD(state)) {
+            qpa_logerr(pa_context_errno(c->context),
+                       "Wrong context state\n");
+            goto unlock_and_fail;
+        }
+
+        /* Wait until the context is ready */
+        pa_threaded_mainloop_wait(c->mainloop);
+    }
+
+    pa_threaded_mainloop_unlock(c->mainloop);
+    return c;
+
+unlock_and_fail:
+    pa_threaded_mainloop_unlock(c->mainloop);
+fail:
+    AUD_log (AUDIO_CAP, "Failed to initialize PA context");
+    qpa_conn_fini(c);
+    return NULL;
+}
+
+static void *qpa_audio_init(Audiodev *dev)
+{
+    paaudio *g;
+    AudiodevPaOptions *popts = &dev->u.pa;
+    const char *server;
+    PAConnection *c;
+
+    assert(dev->driver == AUDIODEV_DRIVER_PA);
+
+    if (!popts->has_server) {
+        char pidfile[64];
+        char *runtime;
+        struct stat st;
+
+        runtime = getenv("XDG_RUNTIME_DIR");
+        if (!runtime) {
+            return NULL;
+        }
+        snprintf(pidfile, sizeof(pidfile), "%s/pulse/pid", runtime);
+        if (stat(pidfile, &st) != 0) {
+            return NULL;
+        }
+    }
+
+    if (!qpa_validate_per_direction_opts(dev, popts->in)) {
+        return NULL;
+    }
+    if (!qpa_validate_per_direction_opts(dev, popts->out)) {
+        return NULL;
+    }
+
+    g = g_malloc0(sizeof(paaudio));
+    server = popts->has_server ? popts->server : NULL;
+
+    g->dev = dev;
+
+    QTAILQ_FOREACH(c, &pa_conns, list) {
+        if (server == NULL || c->server == NULL ?
+            server == c->server :
+            strcmp(server, c->server) == 0) {
+            g->conn = c;
+            break;
+        }
+    }
+    if (!g->conn) {
+        g->conn = qpa_conn_init(server);
+    }
+    if (!g->conn) {
+        g_free(g);
+        return NULL;
+    }
+
+    ++g->conn->refcount;
+    return g;
+}
+
+static void qpa_conn_fini(PAConnection *c)
+{
+    if (c->mainloop) {
+        pa_threaded_mainloop_stop(c->mainloop);
+    }
+
+    if (c->context) {
+        pa_context_disconnect(c->context);
+        pa_context_unref(c->context);
+    }
+
+    if (c->mainloop) {
+        pa_threaded_mainloop_free(c->mainloop);
+    }
+
+    QTAILQ_REMOVE(&pa_conns, c, list);
+    g_free(c);
+}
+
+static void qpa_audio_fini (void *opaque)
+{
+    paaudio *g = opaque;
+    PAConnection *c = g->conn;
+
+    if (--c->refcount == 0) {
+        qpa_conn_fini(c);
+    }
+
+    g_free(g);
+}
+
+static struct audio_pcm_ops qpa_pcm_ops = {
+    .init_out = qpa_init_out,
+    .fini_out = qpa_fini_out,
+    .write    = qpa_write,
+    .get_buffer_out = qpa_get_buffer_out,
+    .put_buffer_out = qpa_put_buffer_out,
+    .volume_out = qpa_volume_out,
+
+    .init_in  = qpa_init_in,
+    .fini_in  = qpa_fini_in,
+    .read     = qpa_read,
+    .get_buffer_in = qpa_get_buffer_in,
+    .put_buffer_in = qpa_put_buffer_in,
+    .volume_in = qpa_volume_in
+};
+
+static struct audio_driver pa_audio_driver = {
+    .name           = "pa",
+    .descr          = "http://www.pulseaudio.org/",
+    .init           = qpa_audio_init,
+    .fini           = qpa_audio_fini,
+    .pcm_ops        = &qpa_pcm_ops,
+    .can_be_default = 1,
+    .max_voices_out = INT_MAX,
+    .max_voices_in  = INT_MAX,
+    .voice_size_out = sizeof (PAVoiceOut),
+    .voice_size_in  = sizeof (PAVoiceIn),
+};
+
+static void register_audio_pa(void)
+{
+    audio_driver_register(&pa_audio_driver);
+}
+type_init(register_audio_pa);