On Wed, 01 Feb 2017, Hugues Fruchet wrote:
> EOS (End Of Stream) support allows user to get
> all the potential decoded frames remaining in decoder
> pipeline after having reached the end of video bitstream.
> To do so, user calls VIDIOC_DECODER_CMD(V4L2_DEC_CMD_STOP)
> which will drain the decoder and get the drained frames
> that are then returned to user.
> User is informed of EOS completion in two ways:
> - dequeue of an empty frame flagged to V4L2_BUF_FLAG_LAST
> - reception of a V4L2_EVENT_EOS event.
> If, unfortunately, no buffer is available on CAPTURE queue
> to return the empty frame, EOS is delayed till user queue
> one CAPTURE buffer.
>
> Signed-off-by: Hugues Fruchet <hugues.fruchet@xxxxxx>
Acked-by: Peter Griffin <peter.griffin@xxxxxxxxxx>
> ---
> drivers/media/platform/sti/delta/delta-v4l2.c | 146 +++++++++++++++++++++++++-
> drivers/media/platform/sti/delta/delta.h | 23 ++++
> 2 files changed, 168 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/media/platform/sti/delta/delta-v4l2.c b/drivers/media/platform/sti/delta/delta-v4l2.c
> index 237a938..c959614 100644
> --- a/drivers/media/platform/sti/delta/delta-v4l2.c
> +++ b/drivers/media/platform/sti/delta/delta-v4l2.c
> @@ -106,7 +106,8 @@ static void delta_frame_done(struct delta_ctx *ctx, struct delta_frame *frame,
> vbuf->sequence = ctx->frame_num++;
> v4l2_m2m_buf_done(vbuf, err ? VB2_BUF_STATE_ERROR : VB2_BUF_STATE_DONE);
>
> - ctx->output_frames++;
> + if (frame->info.size) /* ignore EOS */
> + ctx->output_frames++;
> }
>
> static void requeue_free_frames(struct delta_ctx *ctx)
> @@ -762,6 +763,135 @@ static int delta_g_selection(struct file *file, void *fh,
> return 0;
> }
>
> +static void delta_complete_eos(struct delta_ctx *ctx,
> + struct delta_frame *frame)
> +{
> + struct delta_dev *delta = ctx->dev;
> + const struct v4l2_event ev = {.type = V4L2_EVENT_EOS};
> +
> + /*
> + * Send EOS to user:
> + * - by returning an empty frame flagged to V4L2_BUF_FLAG_LAST
> + * - and then send EOS event
> + */
> +
> + /* empty frame */
> + frame->info.size = 0;
> +
> + /* set the last buffer flag */
> + frame->flags |= V4L2_BUF_FLAG_LAST;
> +
> + /* release frame to user */
> + delta_frame_done(ctx, frame, 0);
> +
> + /* send EOS event */
> + v4l2_event_queue_fh(&ctx->fh, &ev);
> +
> + dev_dbg(delta->dev, "%s EOS completed\n", ctx->name);
> +}
> +
> +static int delta_try_decoder_cmd(struct file *file, void *fh,
> + struct v4l2_decoder_cmd *cmd)
> +{
> + if (cmd->cmd != V4L2_DEC_CMD_STOP)
> + return -EINVAL;
> +
> + if (cmd->flags & V4L2_DEC_CMD_STOP_TO_BLACK)
> + return -EINVAL;
> +
> + if (!(cmd->flags & V4L2_DEC_CMD_STOP_IMMEDIATELY) &&
> + (cmd->stop.pts != 0))
> + return -EINVAL;
> +
> + return 0;
> +}
> +
> +static int delta_decoder_stop_cmd(struct delta_ctx *ctx, void *fh)
> +{
> + const struct delta_dec *dec = ctx->dec;
> + struct delta_dev *delta = ctx->dev;
> + struct delta_frame *frame = NULL;
> + int ret = 0;
> +
> + dev_dbg(delta->dev, "%s EOS received\n", ctx->name);
> +
> + if (ctx->state != DELTA_STATE_READY)
> + return 0;
> +
> + /* drain the decoder */
> + call_dec_op(dec, drain, ctx);
> +
> + /* release to user drained frames */
> + while (1) {
> + frame = NULL;
> + ret = call_dec_op(dec, get_frame, ctx, &frame);
> + if (ret == -ENODATA) {
> + /* no more decoded frames */
> + break;
> + }
> + if (frame) {
> + dev_dbg(delta->dev, "%s drain frame[%d]\n",
> + ctx->name, frame->index);
> +
> + /* pop timestamp and mark frame with it */
> + delta_pop_dts(ctx, &frame->dts);
> +
> + /* release decoded frame to user */
> + delta_frame_done(ctx, frame, 0);
> + }
> + }
> +
> + /* try to complete EOS */
> + ret = delta_get_free_frame(ctx, &frame);
> + if (ret)
> + goto delay_eos;
> +
> + /* new frame available, EOS can now be completed */
> + delta_complete_eos(ctx, frame);
> +
> + ctx->state = DELTA_STATE_EOS;
> +
> + return 0;
> +
> +delay_eos:
> + /*
> + * EOS completion from driver is delayed because
> + * we don't have a free empty frame available.
> + * EOS completion is so delayed till next frame_queue() call
> + * to be sure to have a free empty frame available.
> + */
> + ctx->state = DELTA_STATE_WF_EOS;
> + dev_dbg(delta->dev, "%s EOS delayed\n", ctx->name);
> +
> + return 0;
> +}
> +
> +static int delta_decoder_cmd(struct file *file, void *fh,
> + struct v4l2_decoder_cmd *cmd)
> +{
> + struct delta_ctx *ctx = to_ctx(fh);
> + int ret = 0;
> +
> + ret = delta_try_decoder_cmd(file, fh, cmd);
> + if (ret)
> + return ret;
> +
> + return delta_decoder_stop_cmd(ctx, fh);
> +}
> +
> +static int delta_subscribe_event(struct v4l2_fh *fh,
> + const struct v4l2_event_subscription *sub)
> +{
> + switch (sub->type) {
> + case V4L2_EVENT_EOS:
> + return v4l2_event_subscribe(fh, sub, 2, NULL);
> + default:
> + return -EINVAL;
> + }
> +
> + return 0;
> +}
> +
> /* v4l2 ioctl ops */
> static const struct v4l2_ioctl_ops delta_ioctl_ops = {
> .vidioc_querycap = delta_querycap,
> @@ -782,6 +912,10 @@ static int delta_g_selection(struct file *file, void *fh,
> .vidioc_streamon = v4l2_m2m_ioctl_streamon,
> .vidioc_streamoff = v4l2_m2m_ioctl_streamoff,
> .vidioc_g_selection = delta_g_selection,
> + .vidioc_try_decoder_cmd = delta_try_decoder_cmd,
> + .vidioc_decoder_cmd = delta_decoder_cmd,
> + .vidioc_subscribe_event = delta_subscribe_event,
> + .vidioc_unsubscribe_event = v4l2_event_unsubscribe,
> };
>
> /*
> @@ -1376,6 +1510,16 @@ static void delta_vb2_frame_queue(struct vb2_buffer *vb)
> struct vb2_v4l2_buffer *vbuf = to_vb2_v4l2_buffer(vb);
> struct delta_frame *frame = to_frame(vbuf);
>
> + if (ctx->state == DELTA_STATE_WF_EOS) {
> + /* new frame available, EOS can now be completed */
> + delta_complete_eos(ctx, frame);
> +
> + ctx->state = DELTA_STATE_EOS;
> +
> + /* return, no need to recycle this buffer to decoder */
> + return;
> + }
> +
> /* recycle this frame */
> delta_recycle(ctx, frame);
> }
> diff --git a/drivers/media/platform/sti/delta/delta.h b/drivers/media/platform/sti/delta/delta.h
> index d4a401b..60c07324 100644
> --- a/drivers/media/platform/sti/delta/delta.h
> +++ b/drivers/media/platform/sti/delta/delta.h
> @@ -27,11 +27,19 @@
> *@DELTA_STATE_READY:
> * Decoding instance is ready to decode compressed access unit.
> *
> + *@DELTA_STATE_WF_EOS:
> + * Decoding instance is waiting for EOS (End Of Stream) completion.
> + *
> + *@DELTA_STATE_EOS:
> + * EOS (End Of Stream) is completed (signaled to user). Decoding instance
> + * should then be closed.
> */
> enum delta_state {
> DELTA_STATE_WF_FORMAT,
> DELTA_STATE_WF_STREAMINFO,
> DELTA_STATE_READY,
> + DELTA_STATE_WF_EOS,
> + DELTA_STATE_EOS
> };
>
> /*
> @@ -237,6 +245,7 @@ struct delta_ipc_param {
> * @get_frame: get the next decoded frame available, see below
> * @recycle: recycle the given frame, see below
> * @flush: (optional) flush decoder, see below
> + * @drain: (optional) drain decoder, see below
> */
> struct delta_dec {
> const char *name;
> @@ -371,6 +380,18 @@ struct delta_dec {
> * decoding logic.
> */
> int (*flush)(struct delta_ctx *ctx);
> +
> + /*
> + * drain() - drain decoder
> + * @ctx: (in) instance
> + *
> + * Optional.
> + * Mark decoder pending frames (decoded but not yet output) as ready
> + * so that they can be output to client at EOS (End Of Stream).
> + * get_frame() is to be called in a loop right after drain() to
> + * get all those pending frames.
> + */
> + int (*drain)(struct delta_ctx *ctx);
> };
>
> struct delta_dev;
> @@ -497,6 +518,8 @@ static inline char *frame_type_str(u32 flags)
> return "P";
> if (flags & V4L2_BUF_FLAG_BFRAME)
> return "B";
> + if (flags & V4L2_BUF_FLAG_LAST)
> + return "EOS";
> return "?";
> }
>
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