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From:   Jernej =?utf-8?B?xaBrcmFiZWM=?= <jernej.skrabec@gmail.com>
To:     Corentin Labbe <clabbe.montjoie@gmail.com>,
        Herbert Xu <herbert@gondor.apana.org.au>,
        "David S . Miller" <davem@davemloft.net>,
        Chen-Yu Tsai <wens@csie.org>,
        Krzysztof Kozlowski <krzysztof.kozlowski+dt@linaro.org>,
        Rob Herring <robh+dt@kernel.org>,
        Samuel Holland <samuel@sholland.org>
Cc:     Samuel Holland <samuel@sholland.org>,
        Albert Ou <aou@eecs.berkeley.edu>,
        Conor Dooley <conor@kernel.org>,
        Palmer Dabbelt <palmer@dabbelt.com>,
        Paul Walmsley <paul.walmsley@sifive.com>,
        devicetree@vger.kernel.org, linux-arm-kernel@lists.infradead.org,
        linux-crypto@vger.kernel.org, linux-kernel@vger.kernel.org,
        linux-riscv@lists.infradead.org, linux-sunxi@lists.linux.dev
Subject: Re: [PATCH v2 2/3] crypto: sun8i-ce - Add TRNG clock to the D1 variant
Date:   Thu, 05 Jan 2023 17:29:34 +0100
Message-ID: <3212177.44csPzL39Z@jernej-laptop>
In-Reply-To: <20221231220146.646-3-samuel@sholland.org>
References: <20221231220146.646-1-samuel@sholland.org>
 <20221231220146.646-3-samuel@sholland.org>
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Dne sobota, 31. december 2022 ob 23:01:44 CET je Samuel Holland napisal(a):
> At least the D1 variant requires a separate clock for the TRNG.
> Without this clock enabled, reading from /dev/hwrng reports:
> 
>    sun8i-ce 3040000.crypto: DMA timeout for TRNG (tm=96) on flow 3
> 
> Experimentation shows that the necessary clock is the SoC's internal
> RC oscillator. This makes sense, as noise from the oscillator can be
> used as a source of entropy.
> 
> Signed-off-by: Samuel Holland <samuel@sholland.org>

Reviewed-by: Jernej Skrabec <jernej.skrabec@gmail.com>

Best regards,
Jernej