[media] v4l: vsp1: bru: Support premultiplied alpha at the BRU inputs

Adjust the BRU blending formula to avoid the multiplication by alpha
when the corresponding input format is premultiplied. As this requires
access to the RPFs connected to the BRU inputs from the BRU module,
store pointers to the RPFs in the BRU structure when validating the
pipeline.

Signed-off-by: Laurent Pinchart <laurent.pinchart+renesas@ideasonboard.com>
Signed-off-by: Mauro Carvalho Chehab <m.chehab@samsung.com>

1 files changed, 18 insertions, 9 deletions

diff --git a/drivers/media/platform/vsp1/vsp1_bru.c b/drivers/media/platform/vsp1/vsp1_bru.c
index f80695480060..d8d49fb7f5ff 100644
--- a/drivers/media/platform/vsp1/vsp1_bru.c
+++ b/drivers/media/platform/vsp1/vsp1_bru.c
@@ -18,6 +18,7 @@
 
 #include "vsp1.h"
 #include "vsp1_bru.h"
+#include "vsp1_rwpf.h"
 
 #define BRU_MIN_SIZE				4U
 #define BRU_MAX_SIZE				8190U
@@ -40,11 +41,6 @@ static inline void vsp1_bru_write(struct vsp1_bru *bru, u32 reg, u32 data)
  * V4L2 Subdevice Core Operations
  */
 
-static bool bru_is_input_enabled(struct vsp1_bru *bru, unsigned int input)
-{
-	return media_entity_remote_pad(&bru->entity.pads[input]) != NULL;
-}
-
 static int bru_s_stream(struct v4l2_subdev *subdev, int enable)
 {
 	struct vsp1_bru *bru = to_bru(subdev);
@@ -84,6 +80,7 @@ static int bru_s_stream(struct v4l2_subdev *subdev, int enable)
 		       VI6_BRU_ROP_AROP(VI6_ROP_NOP));
 
 	for (i = 0; i < 4; ++i) {
+		bool premultiplied = false;
 		u32 ctrl = 0;
 
 		/* Configure all Blend/ROP units corresponding to an enabled BRU
@@ -91,11 +88,15 @@ static int bru_s_stream(struct v4l2_subdev *subdev, int enable)
 		 * disabled BRU inputs are used in ROP NOP mode to ignore the
 		 * SRC input.
 		 */
-		if (bru_is_input_enabled(bru, i))
+		if (bru->inputs[i].rpf) {
 			ctrl |= VI6_BRU_CTRL_RBC;
-		else
+
+			premultiplied = bru->inputs[i].rpf->video.format.flags
+				      & V4L2_PIX_FMT_FLAG_PREMUL_ALPHA;
+		} else {
 			ctrl |= VI6_BRU_CTRL_CROP(VI6_ROP_NOP)
 			     |  VI6_BRU_CTRL_AROP(VI6_ROP_NOP);
+		}
 
 		/* Select the virtual RPF as the Blend/ROP unit A DST input to
 		 * serve as a background color.
@@ -117,10 +118,18 @@ static int bru_s_stream(struct v4l2_subdev *subdev, int enable)
 		 *
 		 *	DSTc = DSTc * (1 - SRCa) + SRCc * SRCa
 		 *	DSTa = DSTa * (1 - SRCa) + SRCa
+		 *
+		 * when the SRC input isn't premultiplied, and to
+		 *
+		 *	DSTc = DSTc * (1 - SRCa) + SRCc
+		 *	DSTa = DSTa * (1 - SRCa) + SRCa
+		 *
+		 * otherwise.
 		 */
 		vsp1_bru_write(bru, VI6_BRU_BLD(i),
 			       VI6_BRU_BLD_CCMDX_255_SRC_A |
-			       VI6_BRU_BLD_CCMDY_SRC_A |
+			       (premultiplied ? VI6_BRU_BLD_CCMDY_COEFY :
+						VI6_BRU_BLD_CCMDY_SRC_A) |
 			       VI6_BRU_BLD_ACMDX_255_SRC_A |
 			       VI6_BRU_BLD_ACMDY_COEFY |
 			       (0xff << VI6_BRU_BLD_COEFY_SHIFT));
@@ -192,7 +201,7 @@ static struct v4l2_rect *bru_get_compose(struct vsp1_bru *bru,
 	case V4L2_SUBDEV_FORMAT_TRY:
 		return v4l2_subdev_get_try_crop(fh, pad);
 	case V4L2_SUBDEV_FORMAT_ACTIVE:
-		return &bru->compose[pad];
+		return &bru->inputs[pad].compose;
 	default:
 		return NULL;
 	}