media: imx: csi: enable double write reduction

For 4:2:0 subsampled YUV formats, avoid chroma overdraw by only writing
chroma for even lines. Reduces necessary write memory bandwidth by 25%.

Signed-off-by: Philipp Zabel <p.zabel@pengutronix.de>
Acked-by: Steve Longerbeam <steve_longerbeam@mentor.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>

diff --git a/drivers/staging/media/imx/imx-media-csi.c b/drivers/staging/media/imx/imx-media-csi.c
index a2d2669..f2d64d1 100644 (file)
--- a/drivers/staging/media/imx/imx-media-csi.c
+++ b/drivers/staging/media/imx/imx-media-csi.c
@@ -357,6 +357,8 @@ static int csi_idmac_setup_channel(struct csi_priv *priv)
                passthrough = (sensor_ep->bus_type != V4L2_MBUS_CSI2 &&
                               sensor_ep->bus.parallel.bus_width >= 16);
                passthrough_bits = 16;
+               /* Skip writing U and V components to odd rows */
+               ipu_cpmem_skip_odd_chroma_rows(priv->idmac_ch);
                break;
        case V4L2_PIX_FMT_YUYV:
        case V4L2_PIX_FMT_UYVY: