media: rkvdec: Support dynamic resolution changes

The mem-to-mem stateless decoder API specifies support for dynamic
resolution changes. In particular, the decoder should accept format
changes on the OUTPUT queue even when buffers have been allocated,
as long as it is not streaming.

Relax restrictions for S_FMT as described in the previous paragraph,
and as long as the codec format remains the same. This aligns it with
the Hantro and Cedrus decoders. This change was mostly based on commit
ae02d494 ("media: hantro: Fix s_fmt for dynamic resolution changes").

Since rkvdec_s_fmt() is now just a wrapper around the output/capture
variants without any additional shared functionality, drop the wrapper
and call the respective functions directly.

Fixes: cd33c830 ("media: rkvdec: Add the rkvdec driver")
Cc: <stable@vger.kernel.org>
Signed-off-by: Chen-Yu Tsai <wenst@chromium.org>
Reviewed-by: Nicolas Dufresne <nicolas.dufresne@collabora.com>
Signed-off-by: Hans Verkuil <hverkuil-cisco@xs4all.nl>
Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>

drivers/staging/media/rkvdec/rkvdec.c

@@ -280,31 +280,20 @@ static int rkvdec_try_output_fmt(struct file *file, void *priv,
 	return 0;
 }
 
-static int rkvdec_s_fmt(struct file *file, void *priv,
-			struct v4l2_format *f,
-			int (*try_fmt)(struct file *, void *,
-				       struct v4l2_format *))
+static int rkvdec_s_capture_fmt(struct file *file, void *priv,
+				struct v4l2_format *f)
 {
 	struct rkvdec_ctx *ctx = fh_to_rkvdec_ctx(priv);
 	struct vb2_queue *vq;
+	int ret;
 
-	if (!try_fmt)
-		return -EINVAL;
-
-	vq = v4l2_m2m_get_vq(ctx->fh.m2m_ctx, f->type);
+	/* Change not allowed if queue is busy */
+	vq = v4l2_m2m_get_vq(ctx->fh.m2m_ctx,
+			     V4L2_BUF_TYPE_VIDEO_CAPTURE_MPLANE);
 	if (vb2_is_busy(vq))
 		return -EBUSY;
 
-	return try_fmt(file, priv, f);
-}
-
-static int rkvdec_s_capture_fmt(struct file *file, void *priv,
-				struct v4l2_format *f)
-{
-	struct rkvdec_ctx *ctx = fh_to_rkvdec_ctx(priv);
-	int ret;
-
-	ret = rkvdec_s_fmt(file, priv, f, rkvdec_try_capture_fmt);
+	ret = rkvdec_try_capture_fmt(file, priv, f);
 	if (ret)
 		return ret;
 
@@ -319,9 +308,20 @@ static int rkvdec_s_output_fmt(struct file *file, void *priv,
 	struct v4l2_m2m_ctx *m2m_ctx = ctx->fh.m2m_ctx;
 	const struct rkvdec_coded_fmt_desc *desc;
 	struct v4l2_format *cap_fmt;
-	struct vb2_queue *peer_vq;
+	struct vb2_queue *peer_vq, *vq;
 	int ret;
 
+	/*
+	 * In order to support dynamic resolution change, the decoder admits
+	 * a resolution change, as long as the pixelformat remains. Can't be
+	 * done if streaming.
+	 */
+	vq = v4l2_m2m_get_vq(m2m_ctx, V4L2_BUF_TYPE_VIDEO_OUTPUT_MPLANE);
+	if (vb2_is_streaming(vq) ||
+	    (vb2_is_busy(vq) &&
+	     f->fmt.pix_mp.pixelformat != ctx->coded_fmt.fmt.pix_mp.pixelformat))
+		return -EBUSY;
+
 	/*
 	 * Since format change on the OUTPUT queue will reset the CAPTURE
 	 * queue, we can't allow doing so when the CAPTURE queue has buffers
@@ -331,7 +331,7 @@ static int rkvdec_s_output_fmt(struct file *file, void *priv,
 	if (vb2_is_busy(peer_vq))
 		return -EBUSY;
 
-	ret = rkvdec_s_fmt(file, priv, f, rkvdec_try_output_fmt);
+	ret = rkvdec_try_output_fmt(file, priv, f);
 	if (ret)
 		return ret;