[PATCH 3/6] media: vsp1: Implement partition algorithm restrictions

[Kieran Bingham <kieran.bingham+renesas@xxxxxxxxxxxxxxxx>]

The partition algorithm introduced to support scaling, and rotation on
Gen3 hardware has some restrictions on pipeline configuration.

The UDS must not be connected after the SRU in a pipeline, and whilst an
SRU can be connected after the UDS, it can only do so in identity mode.

A pipeline with an SRU connected after the UDS will disable any scaling
features of the SRU.

Signed-off-by: Kieran Bingham <kieran.bingham+renesas@xxxxxxxxxxxxxxxx>
---
 drivers/media/platform/vsp1/vsp1_sru.c   |  7 ++++--
 drivers/media/platform/vsp1/vsp1_sru.h   |  1 +
 drivers/media/platform/vsp1/vsp1_video.c | 29 +++++++++++++++++++++++-
 3 files changed, 34 insertions(+), 3 deletions(-)

diff --git a/drivers/media/platform/vsp1/vsp1_sru.c b/drivers/media/platform/vsp1/vsp1_sru.c
index 04e4e05af6ae..f277700e5cc2 100644
--- a/drivers/media/platform/vsp1/vsp1_sru.c
+++ b/drivers/media/platform/vsp1/vsp1_sru.c
@@ -149,7 +149,8 @@ static int sru_enum_frame_size(struct v4l2_subdev *subdev,
 		fse->min_width = format->width;
 		fse->min_height = format->height;
 		if (format->width <= SRU_MAX_SIZE / 2 &&
-		    format->height <= SRU_MAX_SIZE / 2) {
+		    format->height <= SRU_MAX_SIZE / 2 &&
+		    sru->force_identity_mode == false) {
 			fse->max_width = format->width * 2;
 			fse->max_height = format->height * 2;
 		} else {
@@ -201,7 +202,8 @@ static void sru_try_format(struct vsp1_sru *sru,
 
 		if (fmt->width <= SRU_MAX_SIZE / 2 &&
 		    fmt->height <= SRU_MAX_SIZE / 2 &&
-		    output_area > input_area * 9 / 4) {
+		    output_area > input_area * 9 / 4 &&
+		    sru->force_identity_mode == false) {
 			fmt->width = format->width * 2;
 			fmt->height = format->height * 2;
 		} else {
@@ -374,6 +376,7 @@ struct vsp1_sru *vsp1_sru_create(struct vsp1_device *vsp1)
 	v4l2_ctrl_new_custom(&sru->ctrls, &sru_intensity_control, NULL);
 
 	sru->intensity = 1;
+	sru->force_identity_mode = false;
 
 	sru->entity.subdev.ctrl_handler = &sru->ctrls;
 
diff --git a/drivers/media/platform/vsp1/vsp1_sru.h b/drivers/media/platform/vsp1/vsp1_sru.h
index ddb00eadd1ea..28da98d86366 100644
--- a/drivers/media/platform/vsp1/vsp1_sru.h
+++ b/drivers/media/platform/vsp1/vsp1_sru.h
@@ -26,6 +26,7 @@ struct vsp1_sru {
 	struct v4l2_ctrl_handler ctrls;
 
 	unsigned int intensity;
+	bool force_identity_mode;
 };
 
 static inline struct vsp1_sru *to_sru(struct v4l2_subdev *subdev)
diff --git a/drivers/media/platform/vsp1/vsp1_video.c b/drivers/media/platform/vsp1/vsp1_video.c
index e78eadd0295b..9404d7968371 100644
--- a/drivers/media/platform/vsp1/vsp1_video.c
+++ b/drivers/media/platform/vsp1/vsp1_video.c
@@ -31,6 +31,7 @@
 #include "vsp1_hgt.h"
 #include "vsp1_pipe.h"
 #include "vsp1_rwpf.h"
+#include "vsp1_sru.h"
 #include "vsp1_uds.h"
 #include "vsp1_video.h"
 
@@ -480,10 +481,12 @@ static int vsp1_video_pipeline_build_branch(struct vsp1_pipeline *pipe,
 					    struct vsp1_rwpf *input,
 					    struct vsp1_rwpf *output)
 {
+	struct vsp1_device *vsp1 = output->entity.vsp1;
 	struct media_entity_enum ent_enum;
 	struct vsp1_entity *entity;
 	struct media_pad *pad;
 	struct vsp1_brx *brx = NULL;
+	bool sru_found = false;
 	int ret;
 
 	ret = media_entity_enum_init(&ent_enum, &input->entity.vsp1->media_dev);
@@ -540,13 +543,37 @@ static int vsp1_video_pipeline_build_branch(struct vsp1_pipeline *pipe,
 			goto out;
 		}
 
-		/* UDS can't be chained. */
+		if (entity->type == VSP1_ENTITY_SRU) {
+			struct vsp1_sru *sru = to_sru(&entity->subdev);
+
+			/*
+			 * Gen3 partition algorithm restricts SRU double-scaled
+			 * resolution if it is connected after a UDS entity.
+			 */
+			if (vsp1->info->gen == 3 && pipe->uds)
+				sru->force_identity_mode = true;
+
+			sru_found = true;
+		}
+
 		if (entity->type == VSP1_ENTITY_UDS) {
+			/* UDS can't be chained. */
 			if (pipe->uds) {
 				ret = -EPIPE;
 				goto out;
 			}
 
+			/*
+			 * On Gen3 hardware using the partition algorithm, the
+			 * UDS must not be connected after the SRU. Using the
+			 * SRU on Gen3 will always engage the partition
+			 * algorithm.
+			 */
+			if (vsp1->info->gen == 3 && sru_found) {
+				ret = -EPIPE;
+				goto out;
+			}
+
 			pipe->uds = entity;
 			pipe->uds_input = brx ? &brx->entity : &input->entity;
 		}
-- 
2.17.1