[RFC PATCH 19/25] virtio-snd: Add start/stop handler

[Shreyansh Chouhan <chouhan.shreyansh2702@gmail.com>]

Added handlers for VIRTIO_SND_PCM_START and VIRTIO_SND_PCM_STOP.

Signed-off-by: Shreyansh Chouhan <chouhan.shreyansh2702@gmail.com>
---
 hw/audio/virtio-snd.c | 35 +++++++++++++++++++++++++++++++++--
 1 file changed, 33 insertions(+), 2 deletions(-)

diff --git a/hw/audio/virtio-snd.c b/hw/audio/virtio-snd.c
index b74c9e4a1f..1b3e1f75f4 100644
--- a/hw/audio/virtio-snd.c
+++ b/hw/audio/virtio-snd.c
@@ -828,6 +828,36 @@ static uint32_t virtio_snd_handle_pcm_prepare(VirtIOSound *s,
     return sz;
 }
 
+/*
+ * Handles VIRTIO_SND_R_PCM_START.
+ * The function writes the response to the virtqueue element.
+ * Returns the used size in bytes.
+ *
+ * @s: VirtIOSound card
+ * @elem: The request element from control queue
+ */
+static uint32_t virtio_snd_handle_pcm_start_stop(VirtIOSound *s,
+                                                 VirtQueueElement *elem,
+                                                 bool start)
+{
+    virtio_snd_pcm_hdr req;
+    size_t sz;
+
+    sz = iov_to_buf(elem->out_sg, elem->out_num, 0, &req, sizeof(req));
+    assert(sz == sizeof(virtio_snd_pcm_hdr));
+
+    virtio_snd_hdr resp;
+    resp.code = VIRTIO_SND_S_OK;
+
+    virtio_snd_pcm_stream *st = virtio_snd_pcm_get_stream(s, req.stream_id);
+    if (st->direction == VIRTIO_SND_D_OUTPUT)
+        AUD_set_active_out(st->voice.out, start);
+
+    sz = iov_from_buf(elem->in_sg, elem->in_num, 0, &resp, sizeof(resp));
+    assert(sz == sizeof(virtio_snd_hdr));
+    return sz;
+}
+
 /* The control queue handler. Pops an element from the control virtqueue,
  * checks the header and performs the requested action. Finally marks the
  * element as used.
@@ -882,9 +912,10 @@ static void virtio_snd_handle_ctrl(VirtIODevice *vdev, VirtQueue *vq)
             sz = virtio_snd_handle_pcm_prepare(s, elem);
             goto done;
         } else if (ctrl.code == VIRTIO_SND_R_PCM_START) {
-            virtio_snd_log("VIRTIO_SND_R_PCM_START");
+            sz = virtio_snd_handle_pcm_start_stop(s, elem, true);
+            goto done;
         } else if (ctrl.code == VIRTIO_SND_R_PCM_STOP) {
-            virtio_snd_log("VIRTIO_SND_R_PCM_STOP");
+            sz = virtio_snd_handle_pcm_start_stop(s, elem, false);
         } else if (ctrl.code == VIRTIO_SND_R_PCM_RELEASE) {
             virtio_snd_log("VIRTIO_SND_R_PCM_RELEASE");
         } else if (ctrl.code == VIRTIO_SND_R_CHMAP_INFO) {
-- 
2.31.1