[PATCH 2/4] arm64: dts: qcom: sc7280: Add dma-coherent property into venus node

While testing with some higher resolution clips, the venus hardware
triggers a fault due to wrong input data being received. Corruption
was also observed in the captured output when the client dumped it
to a file.

On debugging, this was traced to the venus node not declaring
dma-coherent. As a result, DMA buffers shared between the CPU and the
venus video hardware/controller are not guaranteed to be I/O coherent:
CPU writes to an input buffer can remain in CPU caches without being
visible to the video hardware when it reads the same buffer, so the
hardware receives input data that does not match what the CPU wrote.
Likewise, on the capture path, data written by the video hardware to
the output buffer may not be visible to the CPU, so the client reads
stale or partial data, resulting in corruption.

Add the dma-coherent property to the venus node so that DMA buffers
shared between the CPU and the video hardware and controller remain
coherent.

Fixes: 37613aee2179 ("arm64: dts: qcom: sc7280: Add venus DT node")
Cc: [email protected]
Signed-off-by: Vishnu Reddy <[email protected]>
---
 arch/arm64/boot/dts/qcom/kodiak.dtsi | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/arch/arm64/boot/dts/qcom/kodiak.dtsi b/arch/arm64/boot/dts/qcom/kodiak.dtsi
index f74fa66f1a67..98184760b4bf 100644
--- a/arch/arm64/boot/dts/qcom/kodiak.dtsi
+++ b/arch/arm64/boot/dts/qcom/kodiak.dtsi
@@ -5024,6 +5024,8 @@ venus: video-codec@aa00000 {
 					<&mmss_noc MASTER_VIDEO_P0 0 &mc_virt SLAVE_EBI1 0>;
 			interconnect-names = "cpu-cfg", "video-mem";
 
+			dma-coherent;
+
 			iommus = <&apps_smmu 0x2180 0x20>;
 			memory-region = <&video_mem>;
 

-- 
2.34.1