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From:   Masahiro Yamada <masahiroy@kernel.org>
Date:   Tue, 31 Oct 2023 16:03:18 +0900
Message-ID: <CAK7LNAQ=K9Az9UN0O-tCC6VFwMWgdNJUcHBmmQTn5-Y7_m8OOQ@mail.gmail.com>
Subject: Re: [PATCH 3/3] arm64: boot: Support Flat Image Tree
To:     Tom Rini <trini@konsulko.com>
Cc:     "Russell King (Oracle)" <linux@armlinux.org.uk>,
        Simon Glass <sjg@chromium.org>,
        linux-arm-kernel@lists.infradead.org,
        U-Boot Mailing List <u-boot@lists.denx.de>,
        Catalin Marinas <catalin.marinas@arm.com>,
        Nathan Chancellor <nathan@kernel.org>,
        Nick Desaulniers <ndesaulniers@google.com>,
        Nick Terrell <terrelln@fb.com>,
        Nicolas Schier <nicolas@fjasle.eu>,
        Will Deacon <will@kernel.org>, linux-kbuild@vger.kernel.org,
        linux-kernel@vger.kernel.org
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On Tue, Oct 31, 2023 at 1:12=E2=80=AFAM Tom Rini <trini@konsulko.com> wrote=
:
>
> On Mon, Oct 30, 2023 at 03:35:34PM +0000, Russell King (Oracle) wrote:
> > On Sun, Oct 29, 2023 at 05:46:12AM +1300, Simon Glass wrote:
> > > Hi Masahiro,
> > >
> > > Sure, but that is a separate issue, isn't it? We already support
> > > various boot targets in arm64 but not one that includes the DTs, so
> > > far as I can see. The old arm 'uImage' target is pretty out-of-date
> > > now.
> >
> > Does that mean it can be removed? ;)
> >
> > I've NAK'd FIT support on 32-bit Arm in the past, and I remain of the
> > opinion that boot loader specific packaging of the kernel should not
> > be in the kernel but should be external to it - even more so given the
> > multi-platform nature of 32-bit Arm kernels.
>
> I'll point it out here rather than Simon. As part of
> https://github.com/open-source-firmware FIT is a standard and not "boot
> loader specific". And one of the points of a FIT image is that you can
> easily support multi-platform kernels in a single file (without
> optimizing things further, at a cost in tens of milliseconds on a Pi 3
> anyhow) and with user-controlled security.
>
> --
> Tom


It is a copy of the document in U-Boot.

The file was split into two, but the content is the same.


[original in U-Boot]
https://github.com/u-boot/u-boot/blob/v2023.10/doc/usage/fit/source_file_fo=
rmat.rst


[flat-image-tree]
https://github.com/open-source-firmware/flat-image-tree/blob/v0.8/source/ch=
apter1-introduction.rst
https://github.com/open-source-firmware/flat-image-tree/blob/v0.8/source/ch=
apter2-source-file-format.rst


--
Best Regards
Masahiro Yamada