[PATCH 7/8] media: cedrus: Add support for holding capture buffer

[Jernej Skrabec <jernej.skrabec@xxxxxxxx>]

When frame contains multiple slices and driver works in slice mode, it's
more efficient to hold capture buffer in queue until all slices of a
same frame are decoded.

Add support for that to Cedrus driver by exposing and implementing
V4L2_BUF_CAP_SUPPORTS_M2M_HOLD_CAPTURE_BUF capability.

Signed-off-by: Jernej Skrabec <jernej.skrabec@xxxxxxxx>
---
 drivers/staging/media/sunxi/cedrus/cedrus_dec.c   | 9 +++++++++
 drivers/staging/media/sunxi/cedrus/cedrus_hw.c    | 8 +++++---
 drivers/staging/media/sunxi/cedrus/cedrus_video.c | 1 +
 3 files changed, 15 insertions(+), 3 deletions(-)

diff --git a/drivers/staging/media/sunxi/cedrus/cedrus_dec.c b/drivers/staging/media/sunxi/cedrus/cedrus_dec.c
index d7b54accfe83..68462b99750e 100644
--- a/drivers/staging/media/sunxi/cedrus/cedrus_dec.c
+++ b/drivers/staging/media/sunxi/cedrus/cedrus_dec.c
@@ -31,6 +31,14 @@ void cedrus_device_run(void *priv)
 
 	run.src = v4l2_m2m_next_src_buf(ctx->fh.m2m_ctx);
 	run.dst = v4l2_m2m_next_dst_buf(ctx->fh.m2m_ctx);
+
+	if (v4l2_m2m_release_capture_buf(run.src, run.dst)) {
+		v4l2_m2m_dst_buf_remove(ctx->fh.m2m_ctx);
+		v4l2_m2m_buf_done(run.dst, VB2_BUF_STATE_DONE);
+		run.dst = v4l2_m2m_next_dst_buf(ctx->fh.m2m_ctx);
+	}
+	run.dst->is_held = run.src->flags & V4L2_BUF_FLAG_M2M_HOLD_CAPTURE_BUF;
+
 	run.first_slice =
 		run.src->vb2_buf.timestamp != run.dst->vb2_buf.timestamp;
 
@@ -46,6 +54,7 @@ void cedrus_device_run(void *priv)
 			V4L2_CID_MPEG_VIDEO_MPEG2_SLICE_PARAMS);
 		run.mpeg2.quantization = cedrus_find_control_data(ctx,
 			V4L2_CID_MPEG_VIDEO_MPEG2_QUANTIZATION);
+		run.dst->is_held = false;
 		break;
 
 	case V4L2_PIX_FMT_H264_SLICE:
diff --git a/drivers/staging/media/sunxi/cedrus/cedrus_hw.c b/drivers/staging/media/sunxi/cedrus/cedrus_hw.c
index a942cd9bed57..99fedec80224 100644
--- a/drivers/staging/media/sunxi/cedrus/cedrus_hw.c
+++ b/drivers/staging/media/sunxi/cedrus/cedrus_hw.c
@@ -122,7 +122,7 @@ static irqreturn_t cedrus_irq(int irq, void *data)
 	dev->dec_ops[ctx->current_codec]->irq_clear(ctx);
 
 	src_buf = v4l2_m2m_src_buf_remove(ctx->fh.m2m_ctx);
-	dst_buf = v4l2_m2m_dst_buf_remove(ctx->fh.m2m_ctx);
+	dst_buf = v4l2_m2m_next_dst_buf(ctx->fh.m2m_ctx);
 
 	if (!src_buf || !dst_buf) {
 		v4l2_err(&dev->v4l2_dev,
@@ -136,8 +136,10 @@ static irqreturn_t cedrus_irq(int irq, void *data)
 		state = VB2_BUF_STATE_DONE;
 
 	v4l2_m2m_buf_done(src_buf, state);
-	v4l2_m2m_buf_done(dst_buf, state);
-
+	if (!dst_buf->is_held) {
+		v4l2_m2m_dst_buf_remove(ctx->fh.m2m_ctx);
+		v4l2_m2m_buf_done(dst_buf, state);
+	}
 	v4l2_m2m_job_finish(ctx->dev->m2m_dev, ctx->fh.m2m_ctx);
 
 	return IRQ_HANDLED;
diff --git a/drivers/staging/media/sunxi/cedrus/cedrus_video.c b/drivers/staging/media/sunxi/cedrus/cedrus_video.c
index eeee3efd247b..5153b2bba21e 100644
--- a/drivers/staging/media/sunxi/cedrus/cedrus_video.c
+++ b/drivers/staging/media/sunxi/cedrus/cedrus_video.c
@@ -515,6 +515,7 @@ int cedrus_queue_init(void *priv, struct vb2_queue *src_vq,
 	src_vq->type = V4L2_BUF_TYPE_VIDEO_OUTPUT;
 	src_vq->io_modes = VB2_MMAP | VB2_DMABUF;
 	src_vq->drv_priv = ctx;
+	src_vq->subsystem_flags = VB2_V4L2_FL_SUPPORTS_M2M_HOLD_CAPTURE_BUF;
 	src_vq->buf_struct_size = sizeof(struct cedrus_buffer);
 	src_vq->min_buffers_needed = 1;
 	src_vq->ops = &cedrus_qops;
-- 
2.22.1