[PATCH v3 0/8] An effort to bring DT bindings compliance within U-Boot

Thu Jan 4 12:25:10 CET 2024

Hi,

On 1/4/24 09:18, Sumit Garg wrote:
> Hi Michal,
> 
> On Wed, 3 Jan 2024 at 18:24, Michal Simek <michal.simek at amd.com> wrote:
>>
>>
>>
>> On 12/28/23 12:57, Sumit Garg wrote:
>>> Changes in v3:
>>> --------------
>>> - Patch #4: Minor commit message update
>>> - Patch #5: Replace CONFIG_* with Kconfig options
>>> - Patch #7: Dropped Makefile portion and enabled OF_UPSTREAM for SoC
>>>     instead.
>>> - Patch #1, #3, #6 and #8: Picked up review tags
>>>
>>> Changes in v2:
>>> --------------
>>> - Patch #1: excluded gitab CI config check and added commit description.
>>> - Patch #3: s/UBOOT_DTSI_LOC/u_boot_dtsi_loc/
>>> - Patch #4: s/DEVICE_TREE_LOC/dt_dir/ and s/U-boot/U-Boot/
>>> - Patch #5: s/U-boot/U-Boot/
>>> - Patch #6 and #7: Picked up review tags
>>>
>>> Prerequisite
>>> ------------
>>>
>>> This patch series requires devicetree-rebasing git repo to be added as a
>>> subtree to the main U-Boot repo via:
>>>
>>> $ git subtree add --prefix devicetree-rebasing \
>>>         git://git.kernel.org/pub/scm/linux/kernel/git/devicetree/devicetree-rebasing.git \
>>>         v6.6-dts --squash
>>>
>>> Background
>>> ----------
>>>
>>> This effort started while I was reviewing patch series corresponding to
>>> Qcom platforms [1] which was about to import modified devicetree source
>>> files from Linux kernel. I suppose keeping devicetree files sync with
>>> Linux kernel without any DT bindings schema validation has been a pain
>>> for U-Boot SoC/platform maintainers. There has been past discussions
>>> about a single DT repo but that hasn't come up and Linux kernel remained
>>> the place where DT source files as well as bindings are placed and
>>> maintained.
>>>
>>> However, Linux kernel DT maintainers proposed [2] for U-Boot to rather
>>> use devicetree-rebasing repo [3] which is a forked copy from Linux
>>> kernel for DT source files as well as bindings. It is tagged at every
>>> Linux kernel major release or intermideate release candidates. So here I
>>> have tried to reuse that to bring DT bingings compliance as well as a
>>> standard way to maintain a regular sync of DT source files with Linux
>>> kernel.
>>>
>>> In order to maintain devicetree files sync, U-Boot will maintains a Git
>>> subtree for devicetee-rebasing repo as `devicetee-rebasing/` sub-directory.
>>> It will be regularly updated with every new kernel major release via
>>> subtree pull as follows:
>>>
>>> $ git subtree pull --prefix devicetree-rebasing \
>>>         git://git.kernel.org/pub/scm/linux/kernel/git/devicetree/devicetree-rebasing.git \
>>>         <release-tag> --squash
>>>
>>> The RFC/prototype for this series has been discussed with Linux DT
>>> maintainers as well as U-Boot maintainers here [4]. Now we would like to
>>> reach out to wider U-Boot community to seek feedback.
>>>
>>> [1] https://lore.kernel.org/all/CAFA6WYMLUD9cnkr=R0Uur+1UeTMkKjM2zDdMJtXb3nmrLk+pDg@mail.gmail.com/
>>> [2] https://lore.kernel.org/all/CAL_JsqKEjv2tSGmT+0ZiO7_qbBfhTycbGnhJhYpKDFzfO9jzDg@mail.gmail.com/
>>> [3] https://git.kernel.org/pub/scm/linux/kernel/git/devicetree/devicetree-rebasing.git/
>>> [4] https://github.com/u-boot/u-boot/pull/451
>>>
>>> Changes
>>> -------
>>>
>>> Traditionally, U-Boot placed copies of devicetree source files from Linux
>>> kernel into `arch/<arch>/dts/<name>.dts`, which can be selected via:
>>>
>>> CONFIG_DEFAULT_DEVICE_TREE "<name>"
>>>
>>> SoC/board maintainers are encouraged to migrate to using mirrored copies
>>> from `devicetree-rebasing/` into `dts/arch/<arch>/<vendor>` via:
>>>
>>> CONFIG_OF_UPSTREAM=y
>>> CONFIG_DEFAULT_DEVICE_TREE "<vendor>/<name>"
>>>
>>> An example have been shown for Amlogic meson-gxbb SoC and corresponding
>>> derived boards via patch #7 and #8.
>>>
>>> Devicetree bindings schema checks
>>> ---------------------------------
>>>
>>> With devicetee-rebasing Git subtree, the devicetree bindings are also
>>> regularly synced with Linux kernel as `devicetree-rebasing/Bindings/`
>>> sub-directory. This allows U-Boot to run devicetree bindings schema checks
>>> which will bring compliance to U-Boot core/drivers regarding usage of
>>> devicetree.
>>>
>>> Dependencies
>>> ------------
>>>
>>> The DT schema project must be installed in order to validate the DT schema
>>> binding documents and validate DTS files using the DT schema. The DT schema
>>> project can be installed with pip:
>>>
>>> $ pip3 install dtschema
>>>
>>> Note that 'dtschema' installation requires 'swig' and Python development
>>> files installed first. On Debian/Ubuntu systems:
>>>
>>> $ apt install swig python3-dev
>>>
>>> Several executables (dt-doc-validate, dt-mk-schema, dt-validate) will be
>>> installed. Ensure they are in your PATH (~/.local/bin by default).
>>>
>>> Recommended is also to install yamllint (used by dtschema when present).
>>>
>>> Running checks
>>> --------------
>>>
>>> In order to perform validation of DTB files, use the ``dtbs_check`` target:
>>>
>>> $ make dtbs_check
>>
>> I have been following your guidance here and I have also seen it to work but not
>> sure why. Anyway I have strong suspicious that any Makefile rule is not right.
>>
> 
> Thanks for taking time to test DT schema checks. It looks like your
> suspicion is correct.
> 
>> I am getting this issue.
>>
>> /bin/sh: line 1: @: command not found
>> make[1]: *** [devicetree-rebasing/Bindings/Makefile:68:
>> devicetree-rebasing/Bindings/processed-schema.json] Error 127
>> make: *** [Makefile:1181: dt_binding_check] Error 2
>>
> 
> I was able to reproduce this issue once I installed yamllint on my
> Ubuntu machine.
> 
>>
>> devicetree-rebasing/Bindings/processed-schema.json is not generated properly
>>
>> I am using the latest dt schema
>> $ dt-validate -V
>> 2023.12.dev6+gfb80ec43c204
>>
>> and no issue to run it from Linux source code that's why I expect it is not
>> issue with my PC in general.
>> Do you know what can be wrong?
> 
> The issue here is basically due to old U-Boot Kbuild infrastructure
> which isn't in sync with Linux kernel. This Kbuild commit [1] changes
> aren't present in U-Boot leading to this issue.
> 
> [1] https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=3a2429e1faf40b2aaa481aa4b001a74d222c7e8b
> 
> Following change to adapt bindings Makefile to old U-Boot Kbuild
> expectation should resolve this issue:
> 
> diff --git a/devicetree-rebasing/Bindings/Makefile
> b/devicetree-rebasing/Bindings/Makefile
> index 8b395893bd8..7d08372691c 100644
> --- a/devicetree-rebasing/Bindings/Makefile
> +++ b/devicetree-rebasing/Bindings/Makefile
> @@ -47,9 +47,9 @@ quiet_cmd_mk_schema = SCHEMA  $@
>                        rm -f $$f
> 
>   define rule_chkdt
> -       $(if $(DT_SCHEMA_LINT),$(call cmd,yamllint),)
> -       $(call cmd,chk_bindings)
> -       $(call cmd,mk_schema)
> +       $(if $(DT_SCHEMA_LINT),$(call echo-cmd,yamllint) $(cmd_yamllint),); \
> +       $(call echo-cmd,chk_bindings) $(cmd_chk_bindings); \
> +       $(call echo-cmd,mk_schema) $(cmd_mk_schema)
>   endef
> 
>   DT_DOCS = $(patsubst $(srctree)/%,%,$(shell $(find_all_cmd)))
> 
> If this works for you then I will include it as a separate patch for v4.

yes that works.

Thanks,
Michal