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From:   Rob Herring <robh+dt@kernel.org>
Date:   Mon, 27 Feb 2023 11:17:41 -0600
Message-ID: <CAL_JsqLR9sm+GRU8EP4eO_Ln2UhD=ztdAU834CzP8RSv2s2jQg@mail.gmail.com>
Subject: Re: [PATCH v3 1/2] of: create of_root if no dtb provided
To:     Frank Rowand <frowand.list@gmail.com>
Cc:     =?UTF-8?B?Q2zDqW1lbnQgTMOpZ2Vy?= <clement.leger@bootlin.com>,
        devicetree@vger.kernel.org, linux-kernel@vger.kernel.org,
        Lizhi Hou <lizhi.hou@xilinx.com>,
        Allan Nielsen <allan.nielsen@microchip.com>,
        Horatiu Vultur <horatiu.vultur@microchip.com>,
        Steen Hegelund <steen.hegelund@microchip.com>,
        Thomas Petazzoni <thomas.petazzoni@bootlin.com>
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On Thu, Feb 23, 2023 at 3:34=E2=80=AFPM Frank Rowand <frowand.list@gmail.co=
m> wrote:
>
> When enabling CONFIG_OF on a platform where of_root is not populated by
> firmware, we end up without a root node. In order to apply overlays and
> create subnodes of the root node, we need one. Create this root node
> by unflattening an empty builtin dtb.
>
> If firmware provides a flattened device tree (FDT) then the FDT is
> unflattened via setup_arch().  Otherwise, setup_of() which is called
> immediately after setup_arch(), and will create the default root node
> if it does not exist.

Why do we need a hook after setup_arch() rather than an initcall?

Rob