Re: [PATCH v12 2/2] arm64: boot: Support Flat Image Tree

[Masahiro Yamada <masahiroy@kernel.org>]

On Fri, Mar 29, 2024 at 12:29 PM Simon Glass <sjg@chromium.org> wrote:
>
> Add a script which produces a Flat Image Tree (FIT), a single file
> containing the built kernel and associated devicetree files.
> Compression defaults to gzip which gives a good balance of size and
> performance.
>
> The files compress from about 86MB to 24MB using this approach.
>
> The FIT can be used by bootloaders which support it, such as U-Boot
> and Linuxboot. It permits automatic selection of the correct
> devicetree, matching the compatible string of the running board with
> the closest compatible string in the FIT. There is no need for
> filenames or other workarounds.
>
> Add a 'make image.fit' build target for arm64, as well.
>
> The FIT can be examined using 'dumpimage -l'.
>
> This uses the 'dtbs-list' file but processes only .dtb files, ignoring
> the overlay .dtbo files.
>
> This features requires pylibfdt (use 'pip install libfdt'). It also
> requires compression utilities for the algorithm being used. Supported
> compression options are the same as the Image.xxx files. Use
> FIT_COMPRESSION to select an algorithm other than gzip.
>
> While FIT supports a ramdisk / initrd, no attempt is made to support
> this here, since it must be built separately from the Linux build.
>
> Signed-off-by: Simon Glass <sjg@chromium.org>
> ---
>
> Changes in v12:
> - Avoid showing FIT message if V=0


Acked-by: Masahiro Yamada <masahiroy@kernel.org>


-- 
Best Regards
Masahiro Yamada