[PATCH v7 06/12] virtio-sound: handle VIRTIO_SND_R_PCM_{START,STOP}

[Emmanouil Pitsidianakis <manos.pitsidianakis@linaro.org>]

Handle the start and stop control messages for a stream_id. This request
does nothing at the moment except for replying to it. Audio playback
or capture will be started/stopped here in follow-up commits.

Signed-off-by: Emmanouil Pitsidianakis <manos.pitsidianakis@linaro.org>
---
 hw/virtio/trace-events |  1 +
 hw/virtio/virtio-snd.c | 42 ++++++++++++++++++++++++++++++++++++++++--
 2 files changed, 41 insertions(+), 2 deletions(-)

diff --git a/hw/virtio/trace-events b/hw/virtio/trace-events
index 3e619f778b..8eae1bf881 100644
--- a/hw/virtio/trace-events
+++ b/hw/virtio/trace-events
@@ -165,6 +165,7 @@ virtio_snd_realize(void *snd) "snd %p: realize"
 virtio_snd_unrealize(void *snd) "snd %p: unrealize"
 virtio_snd_handle_ctrl(void *vdev, void *vq) "snd %p: handle ctrl event for queue %p"
 virtio_snd_handle_pcm_info(uint32_t stream) "VIRTIO_SND_R_PCM_INFO called for stream %"PRIu32
+virtio_snd_handle_pcm_start_stop(const char *code, uint32_t stream) "%s called for stream %"PRIu32
 virtio_snd_handle_code(uint32_t val, const char *code) "ctrl code msg val = %"PRIu32" == %s"
 virtio_snd_handle_chmap_info(void) "VIRTIO_SND_CHMAP_INFO called"
 virtio_snd_handle_event(void) "event queue callback called"
diff --git a/hw/virtio/virtio-snd.c b/hw/virtio/virtio-snd.c
index 59b648b509..6946309e40 100644
--- a/hw/virtio/virtio-snd.c
+++ b/hw/virtio/virtio-snd.c
@@ -407,6 +407,40 @@ static uint32_t virtio_snd_pcm_prepare_impl(VirtIOSound *s, uint32_t stream_id)
     return VIRTIO_SND_S_OK;
 }
 
+/*
+ * Handles VIRTIO_SND_R_PCM_START.
+ *
+ * @s: VirtIOSound device
+ * @cmd: The request command queue element from VirtIOSound cmdq field
+ * @start: whether to start or stop the device
+ */
+static void virtio_snd_handle_pcm_start_stop(VirtIOSound *s,
+                                             virtio_snd_ctrl_command *cmd,
+                                             bool start)
+{
+    VirtIOSoundPCMStream *stream;
+    virtio_snd_pcm_hdr req;
+    size_t sz = iov_to_buf(cmd->elem->out_sg,
+                           cmd->elem->out_num,
+                           0,
+                           &req,
+                           sizeof(req));
+    if (sz != sizeof(virtio_snd_pcm_hdr)) {
+        cmd->resp.code = VIRTIO_SND_S_BAD_MSG;
+        return;
+    }
+
+    cmd->resp.code = VIRTIO_SND_S_OK;
+    trace_virtio_snd_handle_pcm_start_stop(start ? "VIRTIO_SND_R_PCM_START" :
+            "VIRTIO_SND_R_PCM_STOP", req.stream_id);
+
+    stream = virtio_snd_pcm_get_stream(s, req.stream_id);
+    if (!stream) {
+        error_report("Invalid stream id: %"PRIu32, req.stream_id);
+        cmd->resp.code = VIRTIO_SND_S_BAD_MSG;
+    }
+}
+
 /*
  * The actual processing done in virtio_snd_process_cmdq().
  *
@@ -441,10 +475,14 @@ process_cmd(VirtIOSound *s, virtio_snd_ctrl_command *cmd)
     case VIRTIO_SND_R_PCM_INFO:
         virtio_snd_handle_pcm_info(s, cmd);
         break;
-    case VIRTIO_SND_R_PCM_SET_PARAMS:
-    case VIRTIO_SND_R_PCM_PREPARE:
     case VIRTIO_SND_R_PCM_START:
+        virtio_snd_handle_pcm_start_stop(s, cmd, true);
+        break;
     case VIRTIO_SND_R_PCM_STOP:
+        virtio_snd_handle_pcm_start_stop(s, cmd, false);
+        break;
+    case VIRTIO_SND_R_PCM_SET_PARAMS:
+    case VIRTIO_SND_R_PCM_PREPARE:
     case VIRTIO_SND_R_PCM_RELEASE:
         cmd->resp.code = VIRTIO_SND_S_NOT_SUPP;
         break;
-- 
2.39.2