Re: [PATCH v3 11/11] arm64: tegra: Add VPR placeholder node on Tegra264

[sashiko-bot@kernel.org]

Thank you for your contribution! Sashiko AI review found 1 potential issue(s) to consider:
- [Medium] Meaningful contradiction between the commit message and the actual device tree source regarding the "reg" property for resizable VPR. The commit message states that 'if the VPR is resizable, the firmware should remove the "reg" property', implying it is present by default. However, the device tree node explicitly comments out the `reg` property, and its comment states that it 'assumes resizable VPR by default' and that fixed VPR must 'add the missing "reg" property'.
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commit 6b6b37b0bf4380a0dd429f1a01402c6ffedb5c1f
Author: Thierry Reding <treding@nvidia.com>

arm64: tegra: Add VPR placeholder node on Tegra264

This commit adds a placeholder VPR (Video Protection Region) node for Tegra264
in the device tree. It includes default properties for a resizable VPR, along
with comments indicating how firmware should update the node for either fixed
or resizable VPR scenarios.

> Similarly, if the VPR is
> resizable, the firmware should remove the "reg" property since it is no
> longer needed.

[Severity: Medium]
Is this description in the commit message accurate? The device tree source
node comments out the "reg" property by default, so firmware wouldn't be able
to remove it for a resizable VPR. The inline comments in the implementation
also state that firmware should add the missing "reg" property for fixed VPR:

> diff --git a/arch/arm64/boot/dts/nvidia/tegra264.dtsi b/arch/arm64/boot/dts/nvidia/tegra264.dtsi
> --- a/arch/arm64/boot/dts/nvidia/tegra264.dtsi
> +++ b/arch/arm64/boot/dts/nvidia/tegra264.dtsi
[ ... ]
> +			/*
> +			 * The below assumes resizable VPR by default. If the
> +			 * firmwares sets up fixed VPR, it is responsible for
> +			 * adding the missing "reg" property, removing any of
> +			 * the unused properties, as well as adding a unit-
> +			 * address matching the "reg" property.
> +			 */
> +
> +			/* fixed VPR */
> +			/*
> +			reg = <0x0 0x0 0x0 0x0>;
> +			no-map;
> +			*/

Could the commit message be updated to match the implementation, or should the
"reg" property be uncommented in the dtsi file?

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Sashiko AI review · https://sashiko.dev/#/patchset/20260701-tegra-vpr-v3-0-d80f7b871bb4@nvidia.com?part=11