Re: [PATCH] ARM: dts: rk356x: Use RNG node from upstream DTSI

[Ahmad Fatoum <a.fatoum@pengutronix.de>]

Hi,

On 11.12.24 07:32, Alexander Shiyan wrote:
> Since the RNG node was added to the upstream DTSI, let's reuse it.
> Keep the compatibility string to support the barebox HWRNG driver.
> 
> Signed-off-by: Alexander Shiyan <eagle.alexander923@gmail.com>
> ---
>  arch/arm/dts/rk356x.dtsi | 12 ++++--------
>  1 file changed, 4 insertions(+), 8 deletions(-)
> 
> diff --git a/arch/arm/dts/rk356x.dtsi b/arch/arm/dts/rk356x.dtsi
> index fbabf2a6a6..1a51b9f1b9 100644
> --- a/arch/arm/dts/rk356x.dtsi
> +++ b/arch/arm/dts/rk356x.dtsi
> @@ -44,14 +44,6 @@ cpu_id: id@a {
>  			reg = <0x0a 0x10>;
>  		};
>  	};
> -
> -	rng: rng@fe388000 {
> -		compatible = "rockchip,rk3568-rng", "rockchip,cryptov2-rng";
> -		reg = <0x0 0xfe388000 0x0 0x2000>;
> -		clocks = <&cru CLK_TRNG_NS>, <&cru HCLK_TRNG_NS>;
> -		clock-names = "trng_clk", "trng_hclk";
> -		resets = <&cru SRST_TRNG_NS>;
> -	};
>  };
>  
>  &pmugrf {
> @@ -62,3 +54,7 @@ reboot_mode_pmugrf: reboot-mode {
>  		mode-serial = <0xef08a53c>; /* rk-usb-loader */
>  	};
>  };
> +
> +&rng {
> +	compatible = "rockchip,rk3568-rng", "rockchip,cryptov2-rng";

Now that there is an upstream compatible binding, I think we should
just add "rockchip,rk3568-rng" compatible to the RNG driver
and drop our DT override completely.

Interestingly, upstream enables the node only for the rk3568 and not
the rk3566. The reasoning appears to be that the rk3566 has way lower
quality than expected and enabling it is unsafe[1].

I think we should follow suit in barebox, but it's appropriate for
the commit message to point out that this change disables the
HWRNG on the RK3566.

[1]: https://lore.kernel.org/all/302bdae2f4defeefe88ea4018a0be11f@manjaro.org/

Cheers,
Ahmad

> +};


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