Re: [PATCH 3/3] arm64: dts: meson: g12a: Add hwrng node

[Neil Armstrong]

On 20/05/2019 19:45, Martin Blumenstingl wrote:
> Hi Neil,
> 
> On Mon, May 20, 2019 at 3:49 PM Neil Armstrong <narmstrong@xxxxxxxxxxxx> wrote:
>>
>> The Amlogic G12A has the hwrng module in an unknown "EFUSE" bus.
>>
>> The hwrng is not enabled on the vendor G12A DTs, but is enabled on
>> next generation SM1 SoC family sharing the exact same memory mapping.
>>
>> Let's add the "EFUSE" bus and the hwrng node.
>>
>> This hwrng has been checked with the rng-tools rngtest FIPS tool :
>> rngtest: starting FIPS tests...
>> rngtest: bits received from input: 1630240032
>> rngtest: FIPS 140-2 successes: 81436
>> rngtest: FIPS 140-2 failures: 76
>> rngtest: FIPS 140-2(2001-10-10) Monobit: 10
>> rngtest: FIPS 140-2(2001-10-10) Poker: 6
>> rngtest: FIPS 140-2(2001-10-10) Runs: 26
>> rngtest: FIPS 140-2(2001-10-10) Long run: 34
>> rngtest: FIPS 140-2(2001-10-10) Continuous run: 0
>> rngtest: input channel speed: (min=3.784; avg=5687.521; max=19073.486)Mibits/s
>> rngtest: FIPS tests speed: (min=47.684; avg=52.348; max=52.835)Mibits/s
>> rngtest: Program run time: 30000987 microseconds
>>
>> Signed-off-by: Neil Armstrong <narmstrong@xxxxxxxxxxxx>
>> ---
>>  arch/arm64/boot/dts/amlogic/meson-g12a.dtsi | 13 +++++++++++++
>>  1 file changed, 13 insertions(+)
>>
>> diff --git a/arch/arm64/boot/dts/amlogic/meson-g12a.dtsi b/arch/arm64/boot/dts/amlogic/meson-g12a.dtsi
>> index 8fcdd12f684a..19ef6a467d63 100644
>> --- a/arch/arm64/boot/dts/amlogic/meson-g12a.dtsi
>> +++ b/arch/arm64/boot/dts/amlogic/meson-g12a.dtsi
>> @@ -197,6 +197,19 @@
>>                                 };
>>                         };
>>
>> +                       apb_efuse: bus@30000 {
>> +                               compatible = "simple-bus";
>> +                               reg = <0x0 0x30000 0x0 0x1000>;
> the public S922X datasheet lists the range as FF630000 - FF631FFF
> that translates to a size of 0x2000, which the vendor kernel
> (kernel/aml-4.9/arch/arm64/boot/dts/amlogic/mesong12a.dtsi from
> buildroot-openlinux-A113-201901) seems to use as well:
>   io_efuse_base{
>     reg = <0x0 0xff630000 0x0 0x2000>;
>   };
> 
> where did you take the size from?

Another typo, it's 0x2000.

> 
>> +                               #address-cells = <2>;
>> +                               #size-cells = <2>;
>> +                               ranges = <0x0 0x0 0x0 0x30000 0x0 0x1000>;
> (see reg property above)
> 
>> +
>> +                               hwrng: rng {
> this should be rng@218

Exact.

> 
> 
> Martin
> 

Neil