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From:   Chen-Yu Tsai <wens@csie.org>
Date:   Mon, 19 Mar 2018 10:14:19 +0800
Message-ID: <CAGb2v65QHkuM2GmT4MC+tp+HqN2ecqeZt8bB5OvZm2br1AJJ-w@mail.gmail.com>
Subject: Re: [PATCH v4 10/10] ARM: sunxi: smp: Add initialization of CNTVOFF
To:     =?UTF-8?Q?Myl=C3=A8ne_Josserand?= <mylene.josserand@bootlin.com>
Cc:     Marc Zyngier <marc.zyngier@arm.com>,
        Maxime Ripard <maxime.ripard@bootlin.com>,
        Russell King <linux@armlinux.org.uk>,
        Rob Herring <robh+dt@kernel.org>,
        Mark Rutland <mark.rutland@arm.com>,
        devicetree <devicetree@vger.kernel.org>,
        quentin.schulz@bootlin.com,
        linux-kernel <linux-kernel@vger.kernel.org>,
        LABBE Corentin <clabbe.montjoie@gmail.com>,
        Thomas Petazzoni <thomas.petazzoni@bootlin.com>,
        linux-arm-kernel <linux-arm-kernel@lists.infradead.org>
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On Mon, Mar 19, 2018 at 3:07 AM, Mylène Josserand
<mylene.josserand@bootlin.com> wrote:
> Hello Mark,
>
> Please, excuse me for this late answer and thank you for the review!
>
> On Wed, 7 Mar 2018 12:18:33 +0000
> Marc Zyngier <marc.zyngier@arm.com> wrote:
>
>> On 23/02/18 13:37, Mylène Josserand wrote:
>> > On Cortex-A7, the CNTVOFF register from arch timer is uninitialized.
>>
>> Only on A7? Is that specific to your platform?
>
> I do not really know other Allwinner's platforms about this subject. At
> least, the sun9i-a80 which is a Cortex-a15/a7 does not need that but it
> is necessary for sun8i-a83t which is a cortex-a7. Maybe, Chen-Yu or
> Maxime could help us on it.

AFAIK all Allwinner CPUs need it if there isn't a firmware (PSCI) layer
beneath the kernel that will do the setup. We just have
"arm,cpu-registers-not-fw-configured" set for all the other SoCs that
have in-kernel SMP support, which includes the A31, A23, A33 and A80.

ChenYu