Re: [PATCH v3 2/3] ARM: dts: Add nvmem node for BCM2711 bootloader public key

[Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>]

On 20/04/2023 14:29, Ivan T. Ivanov wrote:
> From: Tim Gover <tim.gover@raspberrypi.com>
> 
> Make a copy of the bootloader secure-boot public key available to the OS
> via an nvmem node. The placement information is populated by the
> Raspberry Pi firmware[1] if a public key is present in the BCM2711
> bootloader EEPROM.
> 
> [1] https://www.raspberrypi.com/documentation/computers/configuration.html#nvmem-nodes
> 
> Signed-off-by: Tim Gover <tim.gover@raspberrypi.com>
> [iivanov] Added link to documentation.
> Signed-off-by: Ivan T. Ivanov <iivanov@suse.de>
> ---
>  arch/arm/boot/dts/bcm2711-rpi.dtsi | 14 ++++++++++++++
>  1 file changed, 14 insertions(+)
> 
> diff --git a/arch/arm/boot/dts/bcm2711-rpi.dtsi b/arch/arm/boot/dts/bcm2711-rpi.dtsi
> index 98817a6675b9..e30fbe84f9c3 100644
> --- a/arch/arm/boot/dts/bcm2711-rpi.dtsi
> +++ b/arch/arm/boot/dts/bcm2711-rpi.dtsi
> @@ -15,6 +15,7 @@ aliases {
>  		ethernet0 = &genet;
>  		pcie0 = &pcie0;
>  		blconfig = &blconfig;
> +		blpubkey = &blpubkey;
>  	};
>  };
>  
> @@ -67,6 +68,19 @@ blconfig: nvram@0 {
>  		no-map;
>  		status = "disabled";
>  	};
> +
> +	/*
> +	 * RPi4 will copy the binary public key blob (if present) from the bootloader
> +	 * into memory for use by the OS.
> +	 */
> +	blpubkey: nvram@1 {
> +		compatible = "raspberrypi,bootloader-public-key", "nvmem-rmem";
> +		#address-cells = <1>;
> +		#size-cells = <1>;
> +		reg = <0x0 0x0 0x0>;
> +		no-map;
> +		status = "disabled";

Why this is disabled? What external resources are missing?

Best regards,
Krzysztof