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From:   Arnd Bergmann <arnd@arndb.de>
Date:   Tue, 3 May 2022 20:19:58 +0200
Message-ID: <CAK8P3a1q6pJ6pdZav0rWJFR2dAWwz8mpiFRO6vc+TA+L-Sk5uQ@mail.gmail.com>
Subject: Re: [PATCH v6 7/8] ARM: dts: Introduce HPE GXP Device tree
To:     "Hawkins, Nick" <nick.hawkins@hpe.com>
Cc:     Arnd Bergmann <arnd@arndb.de>,
        "Verdun, Jean-Marie" <verdun@hpe.com>,
        Joel Stanley <joel@jms.id.au>,
        Linux ARM <linux-arm-kernel@lists.infradead.org>,
        Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
        Olof Johansson <olof@lixom.net>, SoC Team <soc@kernel.org>,
        Rob Herring <robh+dt@kernel.org>,
        Krzysztof Kozlowski <krzysztof.kozlowski+dt@linaro.org>,
        DTML <devicetree@vger.kernel.org>
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On Tue, May 3, 2022 at 5:07 PM Hawkins, Nick <nick.hawkins@hpe.com> wrote:
> On Mon, May 2, 2022 at 10:40 PM <nick.hawkins@hpe.com> wrote:
> > > +++ b/arch/arm/boot/dts/hpe-bmc-dl360gen10.dts
>
> > In the board specific file, you normally have "aliases", "chosen" and "memory"
> > nodes that define e.g. which uart is used for the console.
>
> This is what I have come up with.
>
> / {
>         #address-cells = <1>;
>         #size-cells = <1>;
>         compatible = "hpe,gxp-dl360gen10", "hpe,gxp";
>         model = "Hewlett Packard Enterprise ProLiant dl360 Gen10";
>
>         aliases {
>                 serial2 = &uartc;
>         };

It's a bit unusual to have a serial2 uart when there is no serial0 or serial1.
Most boards that only have a single uart label it either '0' or '1'.
>
>         chosen {
>                 bootargs = "console=ttyS2,115200";
>         };

Use 'stdout-path' to pick the console device here, not the argument
string.

>
>         memory@40000000 {
>                 device_type = "memory";
>                 reg = <0x40000000 0x20000000>;
>         };
> };


> > > +       memory@40000000 {
> > > +               device_type = "memory";
> > > +               reg = <0x40000000 0x20000000>;
> > > +       };
>
> > If the memory is outside of the SoC, it should not be here.
>
> It is part of the SoC. Should I put it in the axi bus instead? If so would
> I need to create an axi for the .dts as well?

That's fine then. The memory node has to be at the root of the DT, not in a
child node. It's just that most SoCs have the memory in a separate chip
on the board, rather than inside of the SoC itself, so it would be part
of the board file. If the gxp package includes the memory and it's not
an option for the board design, you can leave it in the .dtsi file.

         Arnd