Re: [PATCH v2 1/2] arm64: renesas: r8a78000: add MFIS, MFIS SCP and transport nodes

[sashiko-bot@kernel.org]

Thank you for your contribution! Sashiko AI review found 1 potential issue(s) to consider:
- [Medium] Removing the `prr` node silently breaks SoC revision detection and hardware ID verification in the Renesas SoC initialization driver.
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commit c054ca5a70ce33a42761e6ba3a791607f5814e31
Author: Kuninori Morimoto <kuninori.morimoto.gx@renesas.com>

arm64: renesas: r8a78000: add MFIS, MFIS SCP and transport nodes

This commit describes the MFIS and MFIS SCP instances used for tasks including
inter-processor communication. It removes the PRR node, handling it using the
MFIS compatible instead, and describes the STCM transport area for shared
memory mailboxing.

> diff --git a/arch/arm64/boot/dts/renesas/r8a78000.dtsi b/arch/arm64/boot/dts/renesas/r8a78000.dtsi
> index 3e1c98903cea0..d77bed5326832 100644
> --- a/arch/arm64/boot/dts/renesas/r8a78000.dtsi
> +++ b/arch/arm64/boot/dts/renesas/r8a78000.dtsi
> @@ -678,9 +678,123 @@ soc: soc {
>  		#size-cells = <2>;
>  		ranges;
>  
> -		prr: chipid@189e0044 {
> -			compatible = "renesas,prr";
> -			reg = <0 0x189e0044 0 4>;
> +		mfis: system-controller@189e0000 {
> +			compatible = "renesas,r8a78000-mfis";

Does removing the prr node break SoC revision detection and hardware ID
verification in the Renesas SoC initialization driver?

The drivers/soc/renesas/renesas-soc.c driver uses the renesas_ids array to
find the chip ID register, which currently matches "renesas,prr" and
"renesas,bsid".

The driver can also fall back to a hardcoded family->reg address, but the
fam_rcar_gen5 family structure leaves .reg uninitialized.

Since the prr node is replaced with renesas,r8a78000-mfis without updating
renesas_ids, will renesas_soc_init() fail to map the chip ID register and skip
reading the product register? This would prevent the hardware revision from
populating in sysfs (/sys/devices/soc0/revision).

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Sashiko AI review · https://sashiko.dev/#/patchset/20260519074702.3308-4-wsa+renesas@sang-engineering.com?part=1