[Patch 05/19] media: ti-vpe: cal: Restrict DMA to avoid memory corruption

From: Benoit Parrot <bparrot@ti.com>
To: Hans Verkuil <hverkuil@xs4all.nl>, Rob Herring <robh+dt@kernel.org>
Cc: <linux-media@vger.kernel.org>, <devicetree@vger.kernel.org>,
	<linux-kernel@vger.kernel.org>,
	Nikhil Devshatwar <nikhil.nd@ti.com>,
	Benoit Parrot <bparrot@ti.com>
Subject: [Patch 05/19] media: ti-vpe: cal: Restrict DMA to avoid memory corruption
Date: Fri, 18 Oct 2019 10:34:23 -0500	[thread overview]
Message-ID: <20191018153437.20614-6-bparrot@ti.com> (raw)
In-Reply-To: <20191018153437.20614-1-bparrot@ti.com>

From: Nikhil Devshatwar <nikhil.nd@ti.com>

When setting DMA for video capture from CSI channel, if the DMA size
is not given, it ends up writing as much data as sent by the camera.

This may lead to overwriting the buffers causing memory corruption.
Observed green lines on the default framebuffer.

Restrict the DMA to maximum height as specified in the S_FMT ioctl.

Signed-off-by: Nikhil Devshatwar <nikhil.nd@ti.com>
Signed-off-by: Benoit Parrot <bparrot@ti.com>
---
 drivers/media/platform/ti-vpe/cal.c | 6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

diff --git a/drivers/media/platform/ti-vpe/cal.c b/drivers/media/platform/ti-vpe/cal.c
index 78fe2da61d77..62aeedb705e9 100644
--- a/drivers/media/platform/ti-vpe/cal.c
+++ b/drivers/media/platform/ti-vpe/cal.c
@@ -769,12 +769,13 @@ static void pix_proc_config(struct cal_ctx *ctx)
 }
 
 static void cal_wr_dma_config(struct cal_ctx *ctx,
-			      unsigned int width)
+			      unsigned int width, unsigned int height)
 {
 	u32 val;
 
 	val = reg_read(ctx->dev, CAL_WR_DMA_CTRL(ctx->csi2_port));
 	set_field(&val, ctx->csi2_port, CAL_WR_DMA_CTRL_CPORT_MASK);
+	set_field(&val, height, CAL_WR_DMA_CTRL_YSIZE_MASK);
 	set_field(&val, CAL_WR_DMA_CTRL_DTAG_PIX_DAT,
 		  CAL_WR_DMA_CTRL_DTAG_MASK);
 	set_field(&val, CAL_WR_DMA_CTRL_MODE_CONST,
@@ -1397,7 +1398,8 @@ static int cal_start_streaming(struct vb2_queue *vq, unsigned int count)
 	csi2_lane_config(ctx);
 	csi2_ctx_config(ctx);
 	pix_proc_config(ctx);
-	cal_wr_dma_config(ctx, ctx->v_fmt.fmt.pix.bytesperline);
+	cal_wr_dma_config(ctx, ctx->v_fmt.fmt.pix.bytesperline,
+			  ctx->v_fmt.fmt.pix.height);
 	cal_wr_dma_addr(ctx, addr);
 	csi2_ppi_enable(ctx);
 
-- 
2.17.1

