Re: [PATCH] arm64: dts: rockchip: enable rng on all rk356x

[Dragan Simic <dsimic@manjaro.org>]

Hello Peter,

On 2024-12-02 00:46, Peter Robinson wrote:
> The rk356x rng is available on both the rk3566 and rk3568
> parts, the IP is all self contained within the SoCs so
> it's enabled already by default on rk3568 so let's enable
> it in the base rk356x.dtsi so it's enabled consistently
> everywhere.

Please, go through the mailing list threads [1][2] that have led us
to the current state.  To sum it up, it isn't about what's supported
in the two RK356x SoC variants, but about the RK3566's HWRNG being
disabled because the testing showed that it produces unacceptably
low quality of random data, for some yet unknown reason.

[1] 
https://lore.kernel.org/linux-rockchip/cover.1720969799.git.daniel@makrotopia.org/T/#u
[2] 
https://lore.kernel.org/linux-rockchip/cover.1722355365.git.daniel@makrotopia.org/T/#u

> Signed-off-by: Peter Robinson <pbrobinson@gmail.com>
> ---
>  arch/arm64/boot/dts/rockchip/rk3568.dtsi      | 4 ----
>  arch/arm64/boot/dts/rockchip/rk356x-base.dtsi | 1 -
>  2 files changed, 5 deletions(-)
> 
> diff --git a/arch/arm64/boot/dts/rockchip/rk3568.dtsi
> b/arch/arm64/boot/dts/rockchip/rk3568.dtsi
> index ecaefe208e3e..9dc09db5034d 100644
> --- a/arch/arm64/boot/dts/rockchip/rk3568.dtsi
> +++ b/arch/arm64/boot/dts/rockchip/rk3568.dtsi
> @@ -397,10 +397,6 @@ power-domain@RK3568_PD_PIPE {
>  	};
>  };
> 
> -&rng {
> -	status = "okay";
> -};
> -
>  &usb_host0_xhci {
>  	phys = <&usb2phy0_otg>, <&combphy0 PHY_TYPE_USB3>;
>  	phy-names = "usb2-phy", "usb3-phy";
> diff --git a/arch/arm64/boot/dts/rockchip/rk356x-base.dtsi
> b/arch/arm64/boot/dts/rockchip/rk356x-base.dtsi
> index 62be06f3b863..2994cddb3464 100644
> --- a/arch/arm64/boot/dts/rockchip/rk356x-base.dtsi
> +++ b/arch/arm64/boot/dts/rockchip/rk356x-base.dtsi
> @@ -1038,7 +1038,6 @@ rng: rng@fe388000 {
>  		clocks = <&cru CLK_TRNG_NS>, <&cru HCLK_TRNG_NS>;
>  		clock-names = "core", "ahb";
>  		resets = <&cru SRST_TRNG_NS>;
> -		status = "disabled";
>  	};
> 
>  	i2s0_8ch: i2s@fe400000 {