Re: [PATCH v11 2/2] arm64: boot: Support Flat Image Tree

[Masahiro Yamada <masahiroy@kernel.org>]

On Thu, Mar 14, 2024 at 1:28 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 v11:
> - Use dtbslist file in image.fit rule
> - Update cmd_fit rule as per Masahiro
> - Don't mention ignoring files without a .dtb prefix
> - Use argparse fromfile_prefix_chars feature
> - Add a -v option and use it for output (with make V=1)
> - rename srcdir to dtbs
> - Use -o for the output file instead of -f
>




> --- a/scripts/Makefile.lib
> +++ b/scripts/Makefile.lib
> @@ -504,6 +504,21 @@ quiet_cmd_uimage = UIMAGE  $@
>                         -a $(UIMAGE_LOADADDR) -e $(UIMAGE_ENTRYADDR) \
>                         -n '$(UIMAGE_NAME)' -d $< $@
>
> +# Flat Image Tree (FIT)
> +# This allows for packaging of a kernel and all devicetrees files, using
> +# compression.
> +# ---------------------------------------------------------------------------
> +
> +MAKE_FIT := $(srctree)/scripts/make_fit.py
> +
> +# Use this to override the compression algorithm
> +FIT_COMPRESSION ?= gzip
> +
> +quiet_cmd_fit = FIT     $@
> +      cmd_fit = $(MAKE_FIT) -o $@ --arch $(UIMAGE_ARCH) --os linux \
> +               --name '$(UIMAGE_NAME)' $(if $(V),-v) \
> +               --compress $(FIT_COMPRESSION) -k $< @$(word 2,$^)
> +




A nit in your new code.


$(if $(V),-v) does not work for KBUILD_VERBOSE env variable.


It should be

    $(if $(findstring 1,$(KBUILD_VERBOSE)),-v)





-- 
Best Regards
Masahiro Yamada