audio/pwaudio.c: Add Pipewire audio backend for QEMU

This commit adds a new audiodev backend to allow QEMU to use Pipewire as
both an audio sink and source. This backend is available on most systems

Add Pipewire entry points for QEMU Pipewire audio backend
Add wrappers for QEMU Pipewire audio backend in qpw_pcm_ops()
qpw_write function returns the current state of the stream to pwaudio
and Writes some data to the server for playback streams using pipewire
spa_ringbuffer implementation.
qpw_read function returns the current state of the stream to pwaudio and
reads some data from the server for capture streams using pipewire
spa_ringbuffer implementation. These functions qpw_write and qpw_read
are called during playback and capture.
Added some functions that convert pw audio formats to QEMU audio format
and vice versa which would be needed in the pipewire audio sink and
source functions qpw_init_in() & qpw_init_out().
These methods that implement playback and recording will create streams
for playback and capture that will start processing and will result in
the on_process callbacks to be called.
Built a connection to the Pipewire sound system server in the
qpw_audio_init() method.

Signed-off-by: Dorinda Bassey <dbassey@redhat.com>
Reviewed-by: Volker Rümelin <vr_qemu@t-online.de>
Message-Id: <20230417105654.32328-1-dbassey@redhat.com>
Reviewed-by: Marc-André Lureau <marcandre.lureau@redhat.com>

1 files changed, 44 insertions, 0 deletions

diff --git a/qapi/audio.json b/qapi/audio.json
index 4e54c00..e03396a 100644
--- a/qapi/audio.json
+++ b/qapi/audio.json
@@ -325,6 +325,47 @@
     '*server': 'str' } }
 
 ##
+# @AudiodevPipewirePerDirectionOptions:
+#
+# Options of the Pipewire backend that are used for both playback and
+# recording.
+#
+# @name: name of the sink/source to use
+#
+# @stream-name: name of the Pipewire stream created by qemu.  Can be
+#               used to identify the stream in Pipewire when you
+#               create multiple Pipewire devices or run multiple qemu
+#               instances (default: audiodev's id)
+#
+# @latency: latency you want Pipewire to achieve in microseconds
+#           (default 46000)
+#
+# Since: 8.1
+##
+{ 'struct': 'AudiodevPipewirePerDirectionOptions',
+  'base': 'AudiodevPerDirectionOptions',
+  'data': {
+    '*name': 'str',
+    '*stream-name': 'str',
+    '*latency': 'uint32' } }
+
+##
+# @AudiodevPipewireOptions:
+#
+# Options of the Pipewire audio backend.
+#
+# @in: options of the capture stream
+#
+# @out: options of the playback stream
+#
+# Since: 8.1
+##
+{ 'struct': 'AudiodevPipewireOptions',
+  'data': {
+    '*in':     'AudiodevPipewirePerDirectionOptions',
+    '*out':    'AudiodevPipewirePerDirectionOptions' } }
+
+##
 # @AudiodevSdlPerDirectionOptions:
 #
 # Options of the SDL audio backend that are used for both playback and
@@ -416,6 +457,7 @@
             { 'name': 'jack', 'if': 'CONFIG_AUDIO_JACK' },
             { 'name': 'oss', 'if': 'CONFIG_AUDIO_OSS' },
             { 'name': 'pa', 'if': 'CONFIG_AUDIO_PA' },
+            { 'name': 'pipewire', 'if': 'CONFIG_AUDIO_PIPEWIRE' },
             { 'name': 'sdl', 'if': 'CONFIG_AUDIO_SDL' },
             { 'name': 'sndio', 'if': 'CONFIG_AUDIO_SNDIO' },
             { 'name': 'spice', 'if': 'CONFIG_SPICE' },
@@ -456,6 +498,8 @@
                    'if': 'CONFIG_AUDIO_OSS' },
     'pa':        { 'type': 'AudiodevPaOptions',
                    'if': 'CONFIG_AUDIO_PA' },
+    'pipewire':  { 'type': 'AudiodevPipewireOptions',
+                   'if': 'CONFIG_AUDIO_PIPEWIRE' },
     'sdl':       { 'type': 'AudiodevSdlOptions',
                    'if': 'CONFIG_AUDIO_SDL' },
     'sndio':     { 'type': 'AudiodevSndioOptions',