audio: add audiodev properties to frontends

Finally add audiodev= options to audio frontends so users can specify
which backend to use when multiple backends exist.  Not specifying an
audiodev= option currently causes the first audiodev to be used, this is
fixed in the next commit.

Example usage: -audiodev pa,id=foo -device AC97,audiodev=foo

Signed-off-by: Kővágó, Zoltán <DirtY.iCE.hu@gmail.com>
Reviewed-by: Marc-André Lureau <marcandre.lureau@redhat.com>
Message-id: d64db52dda2d0e9d97bc5ab1dd9adf724280fea1.1566168923.git.DirtY.iCE.hu@gmail.com
Signed-off-by: Gerd Hoffmann <kraxel@redhat.com>

1 files changed, 57 insertions, 0 deletions

diff --git a/hw/core/qdev-properties-system.c b/hw/core/qdev-properties-system.c
index fceab9afd5..70bfd4809b 100644
--- a/hw/core/qdev-properties-system.c
+++ b/hw/core/qdev-properties-system.c
@@ -11,6 +11,7 @@
  */
 
 #include "qemu/osdep.h"
+#include "audio/audio.h"
 #include "net/net.h"
 #include "hw/qdev-properties.h"
 #include "qapi/error.h"
@@ -353,6 +354,62 @@ const PropertyInfo qdev_prop_netdev = {
 };
 
 
+/* --- audiodev --- */
+static void get_audiodev(Object *obj, Visitor *v, const char* name,
+                         void *opaque, Error **errp)
+{
+    DeviceState *dev = DEVICE(obj);
+    Property *prop = opaque;
+    QEMUSoundCard *card = qdev_get_prop_ptr(dev, prop);
+    char *p = g_strdup(audio_get_id(card));
+
+    visit_type_str(v, name, &p, errp);
+    g_free(p);
+}
+
+static void set_audiodev(Object *obj, Visitor *v, const char* name,
+                         void *opaque, Error **errp)
+{
+    DeviceState *dev = DEVICE(obj);
+    Property *prop = opaque;
+    QEMUSoundCard *card = qdev_get_prop_ptr(dev, prop);
+    AudioState *state;
+    Error *local_err = NULL;
+    int err = 0;
+    char *str;
+
+    if (dev->realized) {
+        qdev_prop_set_after_realize(dev, name, errp);
+        return;
+    }
+
+    visit_type_str(v, name, &str, &local_err);
+    if (local_err) {
+        error_propagate(errp, local_err);
+        return;
+    }
+
+    state = audio_state_by_name(str);
+
+    if (!state) {
+        err = -ENOENT;
+        goto out;
+    }
+    card->state = state;
+
+out:
+    error_set_from_qdev_prop_error(errp, err, dev, prop, str);
+    g_free(str);
+}
+
+const PropertyInfo qdev_prop_audiodev = {
+    .name = "str",
+    .description = "ID of an audiodev to use as a backend",
+    /* release done on shutdown */
+    .get = get_audiodev,
+    .set = set_audiodev,
+};
+
 void qdev_prop_set_drive(DeviceState *dev, const char *name,
                          BlockBackend *value, Error **errp)
 {