Re: [RFC PATCH 0/7] arm64: Add fit images for sc7180-trogdor and google,lga

[Simon Glass]

Hi Doug!

On 2026-10-20T15:35:18, Douglas Anderson <dianders@xxxxxxxxxxxx> wrote:

> 1. It uses a checked-in .its script to associate metadata with each
>    board's devicetree. Other tools can parse this metadata in order to
>    craft a package that the Pixel bootloader can understand.

One thing I'd like to check before this goes further. In lga.its the
metadata is a string packed into the configuration description
(board_id=...,board_rev=...,soc_id=...,soc_rev=...). The FIT spec
treats 'description' as human-readable text, so this turns a
free-form, undocumented string into an ABI that bootloaders and
packaging tools must parse. I'd much prefer proper properties in the
configuration node, defined in the FIT spec [1], so that every tool
can rely on the same names and types. I'm happy to help get that into
the spec. What do you think?

> How does this series help us?

The FIT_ITS path is a second way to build image.fit alongside
make_fit.py, and much of it repeats what make_fit.py already does: it
puts the root compatible from each DTB into the configuration and
compresses the DTBs. The series adds fdtget/fdtput, sed parsing of
/incbin/ paths and a shell loop in Makefile.lib to do the same for a
hand-written .its file, and the .its files repeat the DTB lists from
the Makefiles. Have you thought about extending make_fit.py to take
the per-board metadata (e.g. from a small file next to the DTs, or via
FIT_EXTRA_ARGS) and to run fdtfactor itself? That would avoid the
in-tree fdtget/fdtput, the mkimage dependency and most of the Makefile
logic, and trogdor would come almost for free.

The new FIT_ITS, FIT_FACTOR_DTBS and FDTFACTOR_ARGS variables aren't
documented anywhere, including the image.fit entry in the arm64 'make
help' output. Please can you add something, perhaps alongside wherever
FIT_DECOMPOSE_DTBS ends up being described.

[1] https://github.com/open-source-firmware/flat-image-tree

Regards,
Simon