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From:   Kevin Hilman <khilman@baylibre.com>
To:     Neil Armstrong <narmstrong@baylibre.com>,
        Martin Blumenstingl <martin.blumenstingl@googlemail.com>
Cc:     linux-amlogic@lists.infradead.org, linux-kernel@vger.kernel.org,
        linux-arm-kernel@lists.infradead.org
Subject: Re: [PATCH 3/3] arm64: dts: meson: g12a: Add hwrng node
In-Reply-To: <f4a1f115-d886-ddf3-c4fc-ea995f10a434@baylibre.com>
References: <20190520134817.25435-1-narmstrong@baylibre.com> <20190520134817.25435-4-narmstrong@baylibre.com> <CAFBinCD6wJnYd3-E=kS6WCZLFebV9JYk-GybBxoMA8qQqGfSHw@mail.gmail.com> <f4a1f115-d886-ddf3-c4fc-ea995f10a434@baylibre.com>
Date:   Thu, 23 May 2019 09:13:57 -0700
Message-ID: <7hblzt408q.fsf@baylibre.com>
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Neil Armstrong <narmstrong@baylibre.com> writes:

> On 20/05/2019 19:45, Martin Blumenstingl wrote:
>> Hi Neil,
>> 
>> On Mon, May 20, 2019 at 3:49 PM Neil Armstrong <narmstrong@baylibre.com> 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@baylibre.com>
>>> ---
>>>  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.
>

Will wait for v2 on this one,

Kevin