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References: <20210304213902.83903-1-marcan@marcan.st> <20210304213902.83903-26-marcan@marcan.st>
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From:   Linus Walleij <linus.walleij@linaro.org>
Date:   Thu, 11 Mar 2021 00:11:22 +0100
Message-ID: <CACRpkdZrFfP3nx=eU-hKKVUfxHHX2J2-__6tjV8hTPgX3qtBDA@mail.gmail.com>
Subject: Re: [RFT PATCH v3 25/27] tty: serial: samsung_tty: Add earlycon
 support for Apple UARTs
To:     Hector Martin <marcan@marcan.st>
Cc:     Linux ARM <linux-arm-kernel@lists.infradead.org>,
        Marc Zyngier <maz@kernel.org>, Rob Herring <robh@kernel.org>,
        Arnd Bergmann <arnd@kernel.org>,
        Olof Johansson <olof@lixom.net>,
        Krzysztof Kozlowski <krzk@kernel.org>,
        Mark Kettenis <mark.kettenis@xs4all.nl>,
        Tony Lindgren <tony@atomide.com>,
        Mohamed Mediouni <mohamed.mediouni@caramail.com>,
        Stan Skowronek <stan@corellium.com>,
        Alexander Graf <graf@amazon.com>,
        Will Deacon <will@kernel.org>,
        Mark Rutland <mark.rutland@arm.com>,
        Andy Shevchenko <andy.shevchenko@gmail.com>,
        Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        Jonathan Corbet <corbet@lwn.net>,
        Catalin Marinas <catalin.marinas@arm.com>,
        Christoph Hellwig <hch@infradead.org>,
        "David S. Miller" <davem@davemloft.net>,
        "open list:OPEN FIRMWARE AND FLATTENED DEVICE TREE BINDINGS" 
        <devicetree@vger.kernel.org>,
        "open list:SERIAL DRIVERS" <linux-serial@vger.kernel.org>,
        Linux Doc Mailing List <linux-doc@vger.kernel.org>,
        linux-samsung-soc <linux-samsung-soc@vger.kernel.org>,
        Linux-Arch <linux-arch@vger.kernel.org>,
        "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
        Arnd Bergmann <arnd@arndb.de>
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On Thu, Mar 4, 2021 at 10:42 PM Hector Martin <marcan@marcan.st> wrote:

> Earlycon support is identical to S3C2410, but Apple SoCs also need
> MMIO mapped as nGnRnE. This is handled generically for normal drivers
> including the normal UART path here, but earlycon uses fixmap and
> runs before that scaffolding is ready.
>
> Since this is the only case where we need this fix, it makes more
> sense to do it here in the UART driver instead of introducing a
> whole fdt nonposted-mmio resolver just for earlycon/fixmap.
>
> Suggested-by: Arnd Bergmann <arnd@arndb.de>
> Signed-off-by: Hector Martin <marcan@marcan.st>

This is as elegant as it gets!
Reviewed-by: Linus Walleij <linus.walleij@linaro.org>

Yours,
Linus Walleij