OF_UPSTREAM vs. additional dtbs

[Jan Kiszka]

On 10.09.24 08:38, Sumit Garg wrote:
> Hi Jan,
> 
> On Thu, 5 Sept 2024 at 12:08, Jan Kiszka <jan.kiszka at siemens.com> wrote:
>>
>> On 04.09.24 19:29, Frank Wunderlich wrote:
>>>
>>>
>>>> Gesendet: Mittwoch, 04. September 2024 um 19:16 Uhr
>>>> Von: "Jan Kiszka" <jan.kiszka at siemens.com>
>>>> OK, our overlay sources are on their way into mainline, will only take
>>>> until 6.12-rc1 to get them here.
> 
> Glad to hear that.
> 
>>>> To accelerate the preparation, I ported
>>>> that change to a local branch - just to find out that OF_UPSTREAM has no
>>>> clue about DT overlays so far. And it is not just that there are no
>>>> build rules for them (that was quickly fixed). It's also that there is
>>>> no way to trigger their build for your u-boot proper.
>>>>
>>>> Are there plans for addressing this? I'm inclined to revive my patch
>>>> that allows to augment dtb-y from the board's config.mk. Better suggestions?
>>>
>>> Hi
>>>
>>> i hang also on this part, in my case i build the dtbos for the vendor and try to use fdtoverlay to merge base-dt with the defined overlays.
>>>
>>> see commits till July 11th
>>>
>>> https://github.com/frank-w/u-boot/commits/2024-07-bpi-ofupstream-all/
>>>
>>> this fails because the target for fdtoverlays needs targets for the dtbos (have used the fdtoverlay target from linux)...
>>> but i build then without dedicated target (while building the basedt).
>>>
>>> maybe you can help solving the "small" problem in makefile.
>>>
>>
>> This is close but not quite the same scenario because I only need "our"
>> dtbos, and there is no need to create dtbs with them applied (they will
>> be used during dt fixup in our case).
>>
>> What I've now done is this:
>>
>> diff --git a/dts/Kconfig b/dts/Kconfig
>> index 569d4be338e..7ea4fd5a79b 100644
>> --- a/dts/Kconfig
>> +++ b/dts/Kconfig
>> @@ -226,11 +226,11 @@ config OF_LIST
>>
>>  config OF_OVERLAY_LIST
>>         string "List of device tree overlays to include for DT control"
>> -       depends on SPL_LOAD_FIT_APPLY_OVERLAY
>>         help
>>           This option specifies a list of device tree overlays to use for DT
>>           control. This option can then be used by a FIT generator to include
>> -         the overlays in the FIT image.
>> +         the overlays in the FIT image or by binman when assembling an image
>> +         that uses overlays during DT fixup.
>>
>>  choice
>>         prompt "OF LIST compression"
>> diff --git a/scripts/Makefile.dts b/scripts/Makefile.dts
>> index 790f3c508f1..dc181240a21 100644
>> --- a/scripts/Makefile.dts
>> +++ b/scripts/Makefile.dts
>> @@ -1,6 +1,7 @@
>>  # SPDX-License-Identifier: GPL-2.0+
>>
>>  dtb-y += $(patsubst %,%.dtb,$(subst ",,$(CONFIG_DEFAULT_DEVICE_TREE) $(CONFIG_OF_LIST) $(CONFIG_SPL_OF_LIST)))
>> +dtb-y += $(patsubst %,%.dtbo,$(subst ",,$(CONFIG_OF_OVERLAY_LIST)))
>>
>>  ifeq ($(CONFIG_OF_UPSTREAM_BUILD_VENDOR),y)
>>  ifeq ($(CONFIG_ARM64),y)
>>
> 
> Yeah that's all you need to build DT overlays from dts/upstream
> subtree. Care to send a proper patch for this?
> 

Can do if you already want this [1]. Our tree [2] where it is currently 
included still has to wait for upstream 6.12, possibly even 6.13 as we 
need one more overlay now.

>>
>> I will also provide a patch to enhance the machinery in dts/upstream
>> /Makefile. This apparently plays no role when building U-Boot, but it
>> would still be useful for validation purposes to have overlay support
>> there.
> 
> As you mentioned we don't use Makefile for U-Boot builds. So it's
> better to directly send that patch for inclusion in the DT rebasing
> tree.

No, this is about our shadow Makefiles, see [3].

Jan

[1] https://github.com/siemens/u-boot/commit/2be0393b1718990abf2feb0b13dbaf79629ce692
[2] https://github.com/siemens/u-boot/commits/jan/iot2050
[3] https://github.com/siemens/u-boot/commit/de3df1fed47d2075bb3f9ecccfaa93a368b58924

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