media: rkvdec: Add required padding

The addresses of two elements of the segmap[][] member are passed to the
hardware which expects 128-bit aligned addresses. However, without this
patch offsetof(struct rkvdec_vp9_priv_tbl, segmap[0]) is an odd number
(2421) but the hardware just ignores the 5 least significant bits of the
address. As a result, the hardware writes the segmentation map to incorrect
locations.

Inserting 11 bytes of padding corrects this situation by making the said
addresses divisible by 16 (i.e. aligned on a 128-bit boundary).
Signed-off-by: NAndrzej Pietrasiewicz <andrzej.p@collabora.com>
Fixes: f25709c4 ("media: rkvdec: Add the VP9 backend")
Reviewed-by: NNicolas Dufresne <nicolas.dufresne@collabora.com>
Signed-off-by: NHans Verkuil <hverkuil-cisco@xs4all.nl>

drivers/staging/media/rkvdec/rkvdec-vp9.c

@@ -84,6 +84,8 @@ struct rkvdec_vp9_probs {
 		struct rkvdec_vp9_inter_frame_probs inter;
 		struct rkvdec_vp9_intra_only_frame_probs intra_only;
 	};
+	/* 128 bit alignment */
+	u8 padding1[11];
 };
 
 /* Data structure describing auxiliary buffer format. */
@@ -1006,6 +1008,7 @@ static int rkvdec_vp9_start(struct rkvdec_ctx *ctx)
 
 	ctx->priv = vp9_ctx;
 
+	BUILD_BUG_ON(sizeof(priv_tbl->probs) % 16); /* ensure probs size is 128-bit aligned */
 	priv_tbl = dma_alloc_coherent(rkvdec->dev, sizeof(*priv_tbl),
 				      &vp9_ctx->priv_tbl.dma, GFP_KERNEL);
 	if (!priv_tbl) {