[PATCH 8/8] v4l: vsp1: Implement left edge partition algorithm overlap

[Kieran Bingham]

Increase the overlap on the left edge to allow a margin to provide
better image scaling

Signed-off-by: Kieran Bingham <kieran.bingham+rene...@ideasonboard.com>
---
 drivers/media/platform/vsp1/vsp1_rpf.c |  7 +++++-
 drivers/media/platform/vsp1/vsp1_uds.c | 39 ++++++++++++++++++++++++---
 2 files changed, 42 insertions(+), 4 deletions(-)

diff --git a/drivers/media/platform/vsp1/vsp1_rpf.c 
b/drivers/media/platform/vsp1/vsp1_rpf.c
index 94541ab4ca36..d08cfd944b7b 100644
--- a/drivers/media/platform/vsp1/vsp1_rpf.c
+++ b/drivers/media/platform/vsp1/vsp1_rpf.c
@@ -247,6 +247,13 @@ struct vsp1_partition_rect *rpf_partition(struct 
vsp1_entity *entity,
        /* Duplicate the target configuration to the RPF */
        partition->rpf = *dest;
 
+       /*
+        * A partition offset, is a request for more input pixels, and a
+        * declaration that the consumer will clip excess.
+        */
+       partition->rpf.width += dest->offset;
+       partition->rpf.left -= dest->offset;
+
        return &partition->rpf;
 }
 
diff --git a/drivers/media/platform/vsp1/vsp1_uds.c 
b/drivers/media/platform/vsp1/vsp1_uds.c
index 9c1fb7ef3c46..9ee476c8db59 100644
--- a/drivers/media/platform/vsp1/vsp1_uds.c
+++ b/drivers/media/platform/vsp1/vsp1_uds.c
@@ -81,6 +81,20 @@ static struct uds_phase uds_phase_calculation(int position, 
int start_phase,
        return phase;
 }
 
+static int uds_left_src_pixel(int pos, int start_phase, int ratio)
+{
+       struct uds_phase phase;
+
+       phase = uds_phase_calculation(pos, start_phase, ratio);
+
+       /* Renesas guard against odd values in these scale ratios here ? */
+       if ((phase.mp == 2 && (phase.residual & 0x01)) ||
+           (phase.mp == 4 && (phase.residual & 0x03)))
+               WARN_ON(1);
+
+       return phase.mp * (phase.prefilt_outpos + (phase.residual ? 1 : 0));
+}
+
 static int uds_start_phase(int pos, int start_phase, int ratio)
 {
        struct uds_phase phase;
@@ -420,6 +434,8 @@ struct vsp1_partition_rect *uds_partition(struct 
vsp1_entity *entity,
        const struct v4l2_mbus_framefmt *input;
        unsigned int hscale;
        unsigned int image_start_phase = 0;
+       unsigned int right_sink;
+       unsigned int margin;
 
        /* Initialise the partition state */
        partition->uds_sink = *dest;
@@ -432,10 +448,25 @@ struct vsp1_partition_rect *uds_partition(struct 
vsp1_entity *entity,
 
        hscale = uds_compute_ratio(input->width, output->width);
 
-       partition->uds_sink.width = dest->width * input->width
-                                 / output->width;
-       partition->uds_sink.left = dest->left * input->width
-                                / output->width;
+       /* Handle 'left' edge of the partitions */
+       if (partition_idx == 0) {
+               margin = 0;
+       } else {
+               margin = hscale < 0x200 ? 32 : /* 8 <  scale */
+                        hscale < 0x400 ? 16 : /* 4 <  scale <= 8 */
+                        hscale < 0x800 ?  8 : /* 2 <  scale <= 4 */
+                                          4;  /* 1 <  scale <= 2, scale <= 1 */
+       }
+
+       partition->uds_sink.left = uds_left_src_pixel(dest->left,
+                                       image_start_phase, hscale);
+
+       partition->uds_sink.offset = margin;
+
+       right_sink = uds_left_src_pixel(dest->left + dest->width - 1,
+                                       image_start_phase, hscale);
+
+       partition->uds_sink.width = right_sink - partition->uds_sink.left + 1;
 
        partition->start_phase = uds_start_phase(partition->uds_source.left,
                                                 image_start_phase, hscale);
-- 
git-series 0.9.1