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From: "Ard Biesheuvel" <ard.biesheuvel@linaro.org>
Date: Wed, 30 Oct 2019 08:44:09 +0100
Message-ID: <CAKv+Gu981sk=GifDZbB-c-QYYP84RweHSmPQFkLPis1UDgrhAg@mail.gmail.com>
Subject: Re: [edk2-devel] How /sys/firmware/fdt getting created
To: Prabhakar Kushwaha <prabhakar.pkin@gmail.com>
Cc: edk2-devel-groups-io <devel@edk2.groups.io>
Content-Type: text/plain; charset="UTF-8"

On Wed, 30 Oct 2019 at 08:36, Prabhakar Kushwaha
<prabhakar.pkin@gmail.com> wrote:
>
> On Wed, Oct 30, 2019 at 12:43 PM Ard Biesheuvel
> <ard.biesheuvel@linaro.org> wrote:
> >
> > On Tue, 29 Oct 2019 at 18:17, Prabhakar Kushwaha
> > <prabhakar.pkin@gmail.com> wrote:
> > >
> > > Hi All,
> > >
> > > I am working on Ubuntu-18.04 with UEFI on ARM64(64 bit) platform. The
> > > UEFI used is having ACPI tables.
> > >
> > > I am trying to understand where and how /sys/firmware/fdt is getting
> > > created. is it created by UEFI or grub and passed to Linux?
> > >
> >
> > Neither. It is created by Linux itself.
> >
> >
> >
>
> Thanks Ard,
>
> Can you please point me the code where it is getting created.
> I want to add below in /sys/firmware/fdt.
>
> #size-cells = <0x02>;
> #address-cells = <0x02>;
>

Actually, in your case it is GRUB not the kernel that creates the FDT.
It does this to pass the initrd information.

So if you want to add these properties, you should add them there.

Can you explain why doing this is necessary?