arm64: dts: rockchip: Describe why is HWRNG disabled in RK356x base dtsi

[PATCH] arm64: dts: rockchip: Describe why is HWRNG disabled in RK356x base dtsi

Posted by Dragan Simic 1 year, 2 months ago

Despite the presence of the hardware random number generator (HWRNG) in the
different Rockchip RK356x SoC variants, it remains disabled for the RK3566
SoC because testing showed [1] that it produces unacceptably low quality of
random data, for some yet unknown reason.  The HWRNG is enabled for the RK3568
SoC, on which the testing showed good quality of the generated random data.

To avoid possible confusion in the future, [2] let's have this described
briefly in the RK356x base SoC dtsi.

[1] https://lore.kernel.org/linux-rockchip/cover.1720969799.git.daniel@makrotopia.org/T/#u
[2] https://lore.kernel.org/linux-rockchip/20241201234613.52322-1-pbrobinson@gmail.com/T/#u

Signed-off-by: Dragan Simic <dsimic@manjaro.org>
---
 arch/arm64/boot/dts/rockchip/rk356x-base.dtsi | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/arch/arm64/boot/dts/rockchip/rk356x-base.dtsi b/arch/arm64/boot/dts/rockchip/rk356x-base.dtsi
index 62be06f3b863..ab8f42c0a843 100644
--- a/arch/arm64/boot/dts/rockchip/rk356x-base.dtsi
+++ b/arch/arm64/boot/dts/rockchip/rk356x-base.dtsi
@@ -1032,6 +1032,11 @@ sdhci: mmc@fe310000 {
 		status = "disabled";
 	};
 
+	/*
+	 * Testing showed that the HWRNG found in RK3566 produces unacceptably
+	 * low quality of random data, so the HWRNG isn't enabled for all RK356x
+	 * SoC variants despite its presence.
+	 */
 	rng: rng@fe388000 {
 		compatible = "rockchip,rk3568-rng";
 		reg = <0x0 0xfe388000 0x0 0x4000>;

Re: [PATCH] arm64: dts: rockchip: Describe why is HWRNG disabled in RK356x base dtsi

Posted by Heiko Stuebner 1 year ago

On Mon, 02 Dec 2024 15:44:06 +0100, Dragan Simic wrote:
> Despite the presence of the hardware random number generator (HWRNG) in the
> different Rockchip RK356x SoC variants, it remains disabled for the RK3566
> SoC because testing showed [1] that it produces unacceptably low quality of
> random data, for some yet unknown reason.  The HWRNG is enabled for the RK3568
> SoC, on which the testing showed good quality of the generated random data.
> 
> To avoid possible confusion in the future, [2] let's have this described
> briefly in the RK356x base SoC dtsi.
> 
> [...]

Applied, thanks!

[1/1] arm64: dts: rockchip: Describe why is HWRNG disabled in RK356x base dtsi
      commit: 5afdb98dcc55917df4a8568fd07a119844a7d391

Best regards,
-- 
Heiko Stuebner <heiko@sntech.de>

Re: [PATCH] arm64: dts: rockchip: Describe why is HWRNG disabled in RK356x base dtsi

Posted by Dragan Simic 1 year ago

Just a brief reminder about this patch...

On 2024-12-02 15:44, Dragan Simic wrote:
> Despite the presence of the hardware random number generator (HWRNG) in 
> the
> different Rockchip RK356x SoC variants, it remains disabled for the 
> RK3566
> SoC because testing showed [1] that it produces unacceptably low 
> quality of
> random data, for some yet unknown reason.  The HWRNG is enabled for the 
> RK3568
> SoC, on which the testing showed good quality of the generated random 
> data.
> 
> To avoid possible confusion in the future, [2] let's have this 
> described
> briefly in the RK356x base SoC dtsi.
> 
> [1] 
> https://lore.kernel.org/linux-rockchip/cover.1720969799.git.daniel@makrotopia.org/T/#u
> [2] 
> https://lore.kernel.org/linux-rockchip/20241201234613.52322-1-pbrobinson@gmail.com/T/#u
> 
> Signed-off-by: Dragan Simic <dsimic@manjaro.org>
> ---
>  arch/arm64/boot/dts/rockchip/rk356x-base.dtsi | 5 +++++
>  1 file changed, 5 insertions(+)
> 
> diff --git a/arch/arm64/boot/dts/rockchip/rk356x-base.dtsi
> b/arch/arm64/boot/dts/rockchip/rk356x-base.dtsi
> index 62be06f3b863..ab8f42c0a843 100644
> --- a/arch/arm64/boot/dts/rockchip/rk356x-base.dtsi
> +++ b/arch/arm64/boot/dts/rockchip/rk356x-base.dtsi
> @@ -1032,6 +1032,11 @@ sdhci: mmc@fe310000 {
>  		status = "disabled";
>  	};
> 
> +	/*
> +	 * Testing showed that the HWRNG found in RK3566 produces 
> unacceptably
> +	 * low quality of random data, so the HWRNG isn't enabled for all 
> RK356x
> +	 * SoC variants despite its presence.
> +	 */
>  	rng: rng@fe388000 {
>  		compatible = "rockchip,rk3568-rng";
>  		reg = <0x0 0xfe388000 0x0 0x4000>;
> 
> _______________________________________________
> Linux-rockchip mailing list
> Linux-rockchip@lists.infradead.org
> http://lists.infradead.org/mailman/listinfo/linux-rockchip

Re: [PATCH] arm64: dts: rockchip: Describe why is HWRNG disabled in RK356x base dtsi

Posted by Diederik de Haas 1 year, 2 months ago

Hi,

I'd have swapped 'is' and 'HWRNG' in the subject, but otherwise ...

On Mon Dec 2, 2024 at 3:44 PM CET, Dragan Simic wrote:
> Despite the presence of the hardware random number generator (HWRNG) in the
> different Rockchip RK356x SoC variants, it remains disabled for the RK3566
> SoC because testing showed [1] that it produces unacceptably low quality of
> random data, for some yet unknown reason.  The HWRNG is enabled for the RK3568
> SoC, on which the testing showed good quality of the generated random data.
>
> To avoid possible confusion in the future, [2] let's have this described
> briefly in the RK356x base SoC dtsi.
>
> [1] https://lore.kernel.org/linux-rockchip/cover.1720969799.git.daniel@makrotopia.org/T/#u
> [2] https://lore.kernel.org/linux-rockchip/20241201234613.52322-1-pbrobinson@gmail.com/T/#u
>
> Signed-off-by: Dragan Simic <dsimic@manjaro.org>
> ---
>  arch/arm64/boot/dts/rockchip/rk356x-base.dtsi | 5 +++++
>  1 file changed, 5 insertions(+)
>
> diff --git a/arch/arm64/boot/dts/rockchip/rk356x-base.dtsi b/arch/arm64/boot/dts/rockchip/rk356x-base.dtsi
> index 62be06f3b863..ab8f42c0a843 100644
> --- a/arch/arm64/boot/dts/rockchip/rk356x-base.dtsi
> +++ b/arch/arm64/boot/dts/rockchip/rk356x-base.dtsi
> @@ -1032,6 +1032,11 @@ sdhci: mmc@fe310000 {
>  		status = "disabled";
>  	};
>  
> +	/*
> +	 * Testing showed that the HWRNG found in RK3566 produces unacceptably
> +	 * low quality of random data, so the HWRNG isn't enabled for all RK356x
> +	 * SoC variants despite its presence.
> +	 */
>  	rng: rng@fe388000 {
>  		compatible = "rockchip,rk3568-rng";
>  		reg = <0x0 0xfe388000 0x0 0x4000>;

Reviewed-by: Diederik de Haas <didi.debian@cknow.org>

Thanks for this :-)

Re: [PATCH] arm64: dts: rockchip: Describe why is HWRNG disabled in RK356x base dtsi

Posted by Dragan Simic 1 year, 2 months ago

Hello Diederik,

On 2024-12-02 18:05, Diederik de Haas wrote:
> I'd have swapped 'is' and 'HWRNG' in the subject, but otherwise ...

Ah, I'd actually write it as "Describe why the HWRNG is disabled
in the RK356x base SoC dtsi", but that's way too long for a patch
summary, so I went with something shorter that also makes it sound
more like a question than a statement. :)

> On Mon Dec 2, 2024 at 3:44 PM CET, Dragan Simic wrote:
>> Despite the presence of the hardware random number generator (HWRNG) 
>> in the
>> different Rockchip RK356x SoC variants, it remains disabled for the 
>> RK3566
>> SoC because testing showed [1] that it produces unacceptably low 
>> quality of
>> random data, for some yet unknown reason.  The HWRNG is enabled for 
>> the RK3568
>> SoC, on which the testing showed good quality of the generated random 
>> data.
>> 
>> To avoid possible confusion in the future, [2] let's have this 
>> described
>> briefly in the RK356x base SoC dtsi.
>> 
>> [1] 
>> https://lore.kernel.org/linux-rockchip/cover.1720969799.git.daniel@makrotopia.org/T/#u
>> [2] 
>> https://lore.kernel.org/linux-rockchip/20241201234613.52322-1-pbrobinson@gmail.com/T/#u
>> 
>> Signed-off-by: Dragan Simic <dsimic@manjaro.org>
>> ---
>>  arch/arm64/boot/dts/rockchip/rk356x-base.dtsi | 5 +++++
>>  1 file changed, 5 insertions(+)
>> 
>> diff --git a/arch/arm64/boot/dts/rockchip/rk356x-base.dtsi 
>> b/arch/arm64/boot/dts/rockchip/rk356x-base.dtsi
>> index 62be06f3b863..ab8f42c0a843 100644
>> --- a/arch/arm64/boot/dts/rockchip/rk356x-base.dtsi
>> +++ b/arch/arm64/boot/dts/rockchip/rk356x-base.dtsi
>> @@ -1032,6 +1032,11 @@ sdhci: mmc@fe310000 {
>>  		status = "disabled";
>>  	};
>> 
>> +	/*
>> +	 * Testing showed that the HWRNG found in RK3566 produces 
>> unacceptably
>> +	 * low quality of random data, so the HWRNG isn't enabled for all 
>> RK356x
>> +	 * SoC variants despite its presence.
>> +	 */
>>  	rng: rng@fe388000 {
>>  		compatible = "rockchip,rk3568-rng";
>>  		reg = <0x0 0xfe388000 0x0 0x4000>;
> 
> Reviewed-by: Diederik de Haas <didi.debian@cknow.org>
> 
> Thanks for this :-)

Thanks. :)

Re: [PATCH] arm64: dts: rockchip: Describe why is HWRNG disabled in RK356x base dtsi

Posted by Dragan Simic 1 year, 2 months ago

On 2024-12-02 15:44, Dragan Simic wrote:
> Despite the presence of the hardware random number generator (HWRNG) in 
> the
> different Rockchip RK356x SoC variants, it remains disabled for the 
> RK3566
> SoC because testing showed [1] that it produces unacceptably low 
> quality of
> random data, for some yet unknown reason.  The HWRNG is enabled for the 
> RK3568
> SoC, on which the testing showed good quality of the generated random 
> data.
> 
> To avoid possible confusion in the future, [2] let's have this 
> described
> briefly in the RK356x base SoC dtsi.
> 
> [1] 
> https://lore.kernel.org/linux-rockchip/cover.1720969799.git.daniel@makrotopia.org/T/#u
> [2] 
> https://lore.kernel.org/linux-rockchip/20241201234613.52322-1-pbrobinson@gmail.com/T/#u
> 
> Signed-off-by: Dragan Simic <dsimic@manjaro.org>

Oh, I forgot to Cc Peter as well while sending this patch, so I did
that now.  Sorry for the noise.

> ---
>  arch/arm64/boot/dts/rockchip/rk356x-base.dtsi | 5 +++++
>  1 file changed, 5 insertions(+)
> 
> diff --git a/arch/arm64/boot/dts/rockchip/rk356x-base.dtsi
> b/arch/arm64/boot/dts/rockchip/rk356x-base.dtsi
> index 62be06f3b863..ab8f42c0a843 100644
> --- a/arch/arm64/boot/dts/rockchip/rk356x-base.dtsi
> +++ b/arch/arm64/boot/dts/rockchip/rk356x-base.dtsi
> @@ -1032,6 +1032,11 @@ sdhci: mmc@fe310000 {
>  		status = "disabled";
>  	};
> 
> +	/*
> +	 * Testing showed that the HWRNG found in RK3566 produces 
> unacceptably
> +	 * low quality of random data, so the HWRNG isn't enabled for all 
> RK356x
> +	 * SoC variants despite its presence.
> +	 */
>  	rng: rng@fe388000 {
>  		compatible = "rockchip,rk3568-rng";
>  		reg = <0x0 0xfe388000 0x0 0x4000>;