[PATCH 2/9] ARM: dts: socfpga: add Enclustra Intel AA1

[Marek Vasut]

On 9/29/24 9:19 PM, Lothar Rubusch wrote:
> On Sun, Sep 29, 2024 at 6:55 PM Marek Vasut <marex at denx.de> wrote:
>>
>> On 9/28/24 12:47 AM, Lothar Rubusch wrote:
>>
>> [...]
>>
>>>>> Ideally I like to setup some Kconfig choice for base board selection
>>>>> and one for boot-mode.
>>>>
>>>>> 1.) In the documentation control.rst I read that the u-boot.dts is
>>>>> combined of several elements. Is there a way to take this base .dts,
>>>>> then add a base board .dtsi by Kconfig option, and similar a
>>>>> boot-mode?
>>>>
>>>> The -u-boot.dtsi is preprocessed by C preprocessor, just like all the
>>>> other DTs, so you can have a -u-boot.dtsi file which contains C
>>>> preprocessor conditional statements in it to conditionally include other
>>>> .dtsi files:
>>>>
>>>> #if IS_ENABLED(...)
>>>> #include ...
>>>> #else ...
>>>> ...
>>>> #endif
>>>
>>> Going through the include list setup by the Makefile made me find my
>>> mistake. Currently I may use u-boot specific stuff in arch/arm/dts and
>>> include generic .dtsi fragments from dts/upstream. Note: I'm not
>>> setting CONFIG_OF_UPSTREAM since I'm using the regular include list
>>> which already contains dts/upstream/src/arm/intel. Is this ok? Or,
>>> shall I try a different approach, which involves having
>>> CONFIG_OF_UPSTREAM explicitely set in the defconfig?
>>
>> I'm not quite sure I understand the question. Once this platform DTs
>> land in mainline and the DTs get synchronized into U-Boot, you should
>> then set CONFIG_OF_UPSTREAM. Until then, you could patch the DTs into
>> dts/upstream/ to test the result with OF_UPSTREAM enabled .
>>
> 
> Ah, sorry. I did not explain well. Currently I patch the DTs which
> should go to kernel/mainline into my local u-boot:
> dts/upstream/src/arm/intel/socfpga/ as a preparation for my test
> builds.

OK

> For U-boot I will need to build a devicetree file from archarm/dts. I
> cannot rely just on the upstream fragments for u-boot. Imagine
> settings like initial fpga bitstream loading, handoff file setup for
> initialization, etc. In parts I may use .dtsi files from dts/upstream,
> though, but most of the u-boot particular devicetree setup will reside
> in arch/arm/dts, I guess (you may see later in the patches).

You should be able to use dts/upstream/src/arm/intel/socfpga/ with 
-u-boot.dtsi from arch/arm/dts/ for this purpose, right ?

> I noticed when setting the option CONFIG_OF_UPSTREAM in `make
> menuconfig`, it prepends `dts/upstream/` to the included paths of the
> devicetree files. The resulting path for the .dts was then
> dts/upstream/arch/arm/dts/ and could not be found anymore. When I
> don't activate CONFIG_OF_UPSTREAM, dts/upstream is in the Makefile's
> include list anyway so that I easily can include from both locations.

+CC Sumit

> In conclusion, currently I'm calling a .dts for building the u-boot DT
> from arch/arm/dts. The file includes upstream stuff as .dtsi fragment
> from dts/upstream and handoff from local. CONFIG_OF_UPSTREAM does not
> seem to be necessary in this case.
> 
> This approach currently works for me. If you strongly disagree, I may
> invest more time to find a way (or why there is currently no way) with
> CONFIG_OF_UPSTREAM.
> 
> This was my question about. Anyway you may wait on v3 to understand
> better in source what I'm doing, or if I'm just messing around.
I'll wait for V3, sure, good luck.

Sorry for the delayed reply.