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From:   Andrey Smirnov <andrew.smirnov@gmail.com>
Date:   Mon, 25 Nov 2019 05:21:45 -0800
Message-ID: <CAHQ1cqF_SW16_cvxpDmn6kYoLQDy7CBRfkftUs=u7gR8SQ=MTw@mail.gmail.com>
Subject: Re: [PATCH v4 1/6] crypto: caam - RNG4 TRNG errata
To:     Horia Geanta <horia.geanta@nxp.com>
Cc:     "linux-crypto@vger.kernel.org" <linux-crypto@vger.kernel.org>,
        Aymen Sghaier <aymen.sghaier@nxp.com>,
        Vipul Kumar <vipul_kumar@mentor.com>,
        Chris Healy <cphealy@gmail.com>,
        Lucas Stach <l.stach@pengutronix.de>,
        Herbert Xu <herbert@gondor.apana.org.au>,
        Iuliana Prodan <iuliana.prodan@nxp.com>,
        "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
        dl-linux-imx <linux-imx@nxp.com>
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On Mon, Nov 25, 2019 at 12:02 AM Horia Geanta <horia.geanta@nxp.com> wrote:
>
> On 11/21/2019 5:56 PM, Andrey Smirnov wrote:
> > The TRNG as used in RNG4, used in CAAM has a documentation issue. The
> I assume the "erratum" consists in RTMCTL[TRNG_ACC] bit
> not being documented, correct?
>
> Is there an ID of the erratum?
> Or at least do you know what parts / SoCs have incorrect documentation?
>
> > effect is that it is possible that the entropy used to instantiate the
> > DRBG may be old entropy, rather than newly generated entropy. There is
> > proper programming guidance, but it is not in the documentation.
> >
> Is the "programming guidance" public?
>

I don't know the answers to any of those questions. I am not the
original author of this change, just ported if from NXP tree because
it seemed important. More than happy to drop this if you think it's
bogus.

Thanks,
Andrey Smirnov