OF_UPSTREAM vs. additional dtbs

[Jan Kiszka]

On 10.09.24 14:36, Frank Wunderlich wrote:
> Am 10. September 2024 14:08:07 MESZ schrieb Jan Kiszka <jan.kiszka at siemens.com>:
>> 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).
> 
> Where do you apply the dtbos? In my case it is
> necessary to build the dtb with overlay as we have
> no way to detect which overlay needs to be
> applied.

In our case, during ft_board_setup, thus dynamically:

https://source.denx.de/u-boot/u-boot/-/blob/7b2d4ecd7f6593771dd3118c8bab525d727a91e0/board/siemens/iot2050/board.c#L474

> 
> We have overlays for different mmc (sdmmc/emmc)
> and spi (nand/ nor) settings which cannot be probed at runtime (or at least we have not found 
> a way to do this).
> 
> 
> Maybe someone can help getting ftdoverlay target working in uboot with the dtbo list.

Yeah, that would be another path that requires additional work. Sorry,
I'm not familiar with those details myself.

Jan

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