[PATCH 2/4] media: rcar-isp: ispcore: Update image data flush settings

[Niklas Söderlund]

Later versions of the datasheet have an updated chapter on how the image
out flush settings depends on proper stride settings. Update the bytes
per line calculation and flush out settings to match the datasheet
clarification.

Signed-off-by: Niklas Söderlund <niklas.soderlund+renesas@xxxxxxxxxxxx>
---
 drivers/media/platform/renesas/rcar-isp/core-io.c | 28 ++++++++++++++++++++---
 drivers/media/platform/renesas/rcar-isp/core.c    |  2 +-
 2 files changed, 26 insertions(+), 4 deletions(-)

diff --git a/drivers/media/platform/renesas/rcar-isp/core-io.c b/drivers/media/platform/renesas/rcar-isp/core-io.c
index badde72352c1..48db37bad69c 100644
--- a/drivers/media/platform/renesas/rcar-isp/core-io.c
+++ b/drivers/media/platform/renesas/rcar-isp/core-io.c
@@ -733,6 +733,28 @@ static const struct v4l2_pix_format_mplane risp_io_capture_default_format = {
 	},
 };
 
+static unsigned int risp_io_calture_bytesperline(unsigned int width, unsigned int bpp)
+{
+	/*
+	 * The datasheet specifies strict alignment and padding rules to be able
+	 * to flush out all the pixels. Each line must be 256 byte aligned and
+	 * at the end of the frame at least one extra line of space must be
+	 * available.
+	 *
+	 * As we can't extend the buffer with one extra line we need to work
+	 * with stride setting to satisfy both constraints. Fortunately the
+	 * datasheet gives us a calculation for this.
+	 *
+	 *   FLUSH[pixels] = ALIGN(WIDTH[pixels], 256)
+	 *
+	 *   PADDING[bytes] = ALIGN(BPP[bytes] * WIDTH[pixels], 256) - BPP[bytes] * WIDTH[pixels] + BPP[bytes] * FLUSH[pixels]
+	 */
+	unsigned int data = bpp * width;
+	unsigned int padding = ALIGN(data, 256) - data + bpp * ALIGN(width, 256);
+
+	return data + padding;
+}
+
 static void risp_io_capture_try_format(struct rcar_isp_core_io *io,
 				       struct v4l2_pix_format_mplane *pix)
 {
@@ -749,16 +771,16 @@ static void risp_io_capture_try_format(struct rcar_isp_core_io *io,
 	case V4L2_PIX_FMT_NV16M:
 		pix->quantization = V4L2_QUANTIZATION_LIM_RANGE;
 		pix->num_planes = 2;
-		pix->plane_fmt[0].bytesperline = ALIGN(pix->width, 256);
+		pix->plane_fmt[0].bytesperline = risp_io_calture_bytesperline(pix->width, 1);
 		pix->plane_fmt[0].sizeimage = pix->plane_fmt[0].bytesperline * pix->height;
-		pix->plane_fmt[1].bytesperline = ALIGN(pix->width, 256);
+		pix->plane_fmt[1].bytesperline = pix->plane_fmt[0].bytesperline;
 		pix->plane_fmt[1].sizeimage = pix->plane_fmt[1].bytesperline * pix->height;
 		break;
 	default:
 		pix->pixelformat = V4L2_PIX_FMT_XBGR32;
 		pix->quantization = V4L2_QUANTIZATION_FULL_RANGE;
 		pix->num_planes = 1;
-		pix->plane_fmt[0].bytesperline = ALIGN(pix->width * 4, 256);
+		pix->plane_fmt[0].bytesperline = risp_io_calture_bytesperline(pix->width, 4);
 		pix->plane_fmt[0].sizeimage = pix->plane_fmt[0].bytesperline * pix->height;
 		break;
 	}
diff --git a/drivers/media/platform/renesas/rcar-isp/core.c b/drivers/media/platform/renesas/rcar-isp/core.c
index b5861d0cd0e8..3e135e84b75b 100644
--- a/drivers/media/platform/renesas/rcar-isp/core.c
+++ b/drivers/media/platform/renesas/rcar-isp/core.c
@@ -398,7 +398,7 @@ static int risp_core_config_output(struct rcar_isp_core *core,
 
 	/* Set image out flush EOF. */
 	risp_core_write(core, ISPCORE_DMA_IMAGE_FLUSH_OUT_REG(index),
-			pix->plane_fmt[0].bytesperline <<
+			ALIGN(pix->width, 256) <<
 			ISPCORE_DMA_IMAGE_FLUSH_OUT_PADDING_PIXEL_EOF_SHIFT);
 
 	/* Enable DMA and set burst length. */

-- 
2.55.0