On Fri, Jan 26, 2024 at 1:04 AM Simon Glass [off-list ref] wrote:

Hi,

On Wed, 17 Jan 2024 at 06:14, Simon Glass [off-list ref] wrote:

quoted

Hi Masahiro, Tom,

On Tue, 9 Jan 2024 at 07:33, Tom Rini [off-list ref] wrote:

quoted

On Tue, Jan 09, 2024 at 11:01:42PM +0900, Masahiro Yamada wrote:

quoted

Hi Simon,


On Wed, Jan 3, 2024 at 8:47 AM Simon Glass [off-list ref] wrote:

quoted

Hi Masahiro,

On Wed, Dec 13, 2023 at 5:14 AM Will Deacon [off-list ref] wrote:

quoted

On Fri, Dec 01, 2023 at 08:54:42PM -0700, Simon Glass wrote:

quoted

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. Use
FIT_COMPRESSION to select a different algorithm.

The FIT can be examined using 'dumpimage -l'.

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. For now there
is no way to change the compression other than by editing the rule for
$(obj)/image.fit

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 v9:
- Move the compression control into Makefile.lib

Changes in v8:
- Drop compatible string in FDT node
- Correct sorting of MAINTAINERS to before ARM64 PORT
- Turn compress part of the make_fit.py comment in to a sentence
- Add two blank lines before parse_args() and setup_fit()
- Use 'image.fit: dtbs' instead of BUILD_DTBS var
- Use '$(<D)/dts' instead of '$(dir $<)dts'
- Add 'mkimage' details Documentation/process/changes.rst
- Allow changing the compression used
- Tweak cover letter since there is only one clean-up patch

Changes in v7:
- Add Image as a dependency of image.fit
- Drop kbuild tag
- Add dependency on dtbs
- Drop unnecessary path separator for dtbs
- Rebase to -next

Changes in v5:
- Drop patch previously applied
- Correct compression rule which was broken in v4

Changes in v4:
- Use single quotes for UIMAGE_NAME

Changes in v3:
- Drop temporary file image.itk
- Drop patch 'Use double quotes for image name'
- Drop double quotes in use of UIMAGE_NAME
- Drop unnecessary CONFIG_EFI_ZBOOT condition for help
- Avoid hard-coding "arm64" for the DT architecture

Changes in v2:
- Drop patch previously applied
- Add .gitignore file
- Move fit rule to Makefile.lib using an intermediate file
- Drop dependency on CONFIG_EFI_ZBOOT
- Pick up .dtb files separately from the kernel
- Correct pylint too-many-args warning for write_kernel()
- Include the kernel image in the file count
- Add a pointer to the FIT spec and mention of its wide industry usage
- Mention the kernel version in the FIT description

 Documentation/process/changes.rst |   9 +
 MAINTAINERS                       |   7 +
 arch/arm64/Makefile               |   7 +-
 arch/arm64/boot/.gitignore        |   1 +
 arch/arm64/boot/Makefile          |   6 +-
 scripts/Makefile.lib              |  16 ++
 scripts/make_fit.py               | 291 ++++++++++++++++++++++++++++++
 7 files changed, 334 insertions(+), 3 deletions(-)
 create mode 100755 scripts/make_fit.py

I'll need Masahiro's Ack on the scripts/ changes before I can take this
one.

Any thoughts on this request, please?

Regards,
Simon

As I mentioned before, I am concerned with having
the same "compatible" entries, with different contents,
as you use the "compatible" string as an ID to selecting
the target config node, right?





$ fdtdump  arch/arm64/boot/image.fit

        ...

        conf-10 {
            compatible = "tq,am642-tqma6442l-mbax4xxl",
"tq,am642-tqma6442l", "ti,am642";
            description = "TQ-Systems TQMa64xxL SoM on MBax4xxL carrier board";
            fdt = "fdt-10";
            kernel = "kernel";
        };

        ...

        conf-25 {
            compatible = "tq,am642-tqma6442l-mbax4xxl",
"tq,am642-tqma6442l", "ti,am642";
            description = "TQ-Systems TQMa64xxL SoM on MBax4xxL carrier board";
            fdt = "fdt-25";
            kernel = "kernel";
        };

I had asked Rob a while ago about if having the same compatible for two
functionally different machines is a feature, or a bug, and I don't
think either of us fully agreed either way. I'd be leaning towards
saying the above example is a bug in the dts files, it's just not been a
bug people have worried about before due to (sadly) how little the
top-level compatible has been used.

Yes I believe this is a bug in the files.

What should the script do in this case? Print a warning, perhaps?

Is there anything I should do here? Would a warning be helpful, or
just confusing?

I do not think it is useful.
You would almost always get a warning, and there is no way to fix it.



With arm64 defconfig, image.fit will include a thousand DTBs.


The config node of my board was listed 214th.
(I found it by fdtdump)


Then, I learned

  >  bootm  ${loadaddr}#conf-214

is the correct command to boot my board.


Of course, the "214" will be different in the future.

The node names, conf-*, are useless.



Only the useful way is to enable CONFIG_FIT_BEST_MATCH in U-Boot,
but this relies on the uniqueness of a compatible string,
which is not true.

(I do not know how to do it in barebox)





I think using the file name as a config node
mitigates the issue because a file name is
considered unique.


For example, with composite DTBs:

imx8mm-venice-gw72xx-0x-imx219-dtbs := imx8mm-venice-gw72xx-0x.dtb
imx8mm-venice-gw72xx-0x-imx219.dtbo
imx8mm-venice-gw72xx-0x-rpidsi-dtbs := imx8mm-venice-gw72xx-0x.dtb
imx8mm-venice-gw72xx-0x-rpidsi.dtbo




configurations {
      imx8mm-venice-gw72xx-0x-imx219 {
            ...
      };

      imx8mm-venice-gw72xx-0x-rpidsi {
            ...
      }
};



Then, we can distinguish them by node, even if they have
the same compatible string.
At least we can do

  > bootm  ${loadaddr}#imx8mm-venice-gw72xx-0x-imx219




For the issue including stale DTBs, you can use my patch:
[PATCH 1/4] kbuild: create a list of all built DTB files
(https://lore.kernel.org/linux-kbuild/CAK7LNASOxi-gzve+_d-sCW9z_eEJ5TMMnzPEvN2Nj2AwgVjF9g@mail.gmail.com/T/#ma3595627a96a04554a78cbbd22056831e13db260 (local))


You can change scripts/make_fit.py to take
the DTB files instead of the directory to search.

Optionally, you can support '@' syntax to
take command arguments from a file.


scripts/make_fit.py ... @arch/$(SRCARCH)/boot/dts/dtbs-list






For the separate base and overlays support,
you can use my patch as a base:
[PATCH 3/4] kbuild: create a list of base and overlays for each DTB
(https://lore.kernel.org/linux-kbuild/CAK7LNASOxi-gzve+_d-sCW9z_eEJ5TMMnzPEvN2Nj2AwgVjF9g@mail.gmail.com/T/#m32c5bdde9098901b7c7776b932827493a05c82d5 (local))





Lastly, you do not need to require mkimage for
args.external.
You can simply concatenate files.







--
Best Regards
Masahiro Yamada

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