Aw: Re: Board code with 2 dts

[Ahmad Fatoum]

Hi Frank,

On 23.03.22 08:47, Frank Wunderlich wrote:
> Hi
> 
> thanks for your fast and detailed answer.
> afaik vendor have not changed the saradc-detection (because v00 was not public), so v00 has same value as v1.0 and i cannot detect difference there. Maybe there is another way to detect (maybe based on gmac or any hardware-change), but for now i used last option you've mentioned (second entry function).

If it's just pre-production HW, it's not worth it to dynamically detect, I agree.

> Have it implemented like kontron-samx6i (both dts currently same), it compiles, can you take a quick look if i did it right?
> 
> https://github.com/frank-w/barebox-r2pro/commit/deaf7a8eed7575e35c17807aa0a432363122b033

Looks ok to me. Nitpick: Using __dtb_z_ instead of __dtb_ and selecting ARM_USE_COMPRESSED_DTB
will decrease barebox size a bit.

> this is not intended to be upstreamed, but for me to fix upstream with v1 config (when i get the board) and still using v00 board.

If v00 is not publicly available, it would be nice if you could replace the existing
v00 support with v01 once you can test it.

Cheers,
Ahmad

> 
> regards Frank
> 
> 
>> Gesendet: Dienstag, 22. März 2022 um 18:34 Uhr
>> Von: "Ahmad Fatoum" <a.fatoum at pengutronix.de>
>> An: frank-w at public-files.de, barebox at lists.infradead.org
>> Betreff: Re: Board code with 2 dts
>>
>> Hello Frank,
>>
>> On 22.03.22 18:23, Frank Wunderlich wrote:
>>> Hi,
>>>
>>> I get information that new hardware revision of bpi-r2 pro has some differences to the version i upstreamed. Is it possible to add a new dts and use same board code?
>>>
>>> How can i choose between the 2 dts on build (kconfig option)?
>>
>> In any case, don't add a new Kconfig option. The existing one suffices.
>>
>>> Afaik the name of dtb is hardcoded in lowlevel.c [1]
>>>
>>> Differences are iodomains (not defined in barebox,but linux) and gmac-config (gmacs swapped and different settings).
>>>
>>> Currently i have not yet the new board for testing,but then i want to send patches for linux and barebox.
>>>
>>> [1] https://git.pengutronix.de/cgit/barebox/tree/arch/arm/boards/rockchip-rk3568-bpi-r2pro/lowlevel.c#n24
>>
>> Is it possible to detect which board is being used?
>> If so, best practice is to have barebox the same image for both
>> and detect board type at runtime.
>> Here's an example doing it in lowlevel.c:
>> arch/arm/boards/stm32mp15xx-dkx/lowlevel.c
>>
>> If you need more barebox infrastructure than what's available in the bootloader
>> to detect board type, you could e.g. rewrite gmac-config in barebox board code
>> after detection.
>>
>> If there is no way to dynamically detect which board variant barebox is running
>> on, just duplicate the entry point in the same file and change just the device
>> tree. Then extend images/Makefile.rockchip to reference the new entry point
>> and barebox build will generate an image for each board. See for example:
>>
>> arch/arm/boards/kontron-samx6i/lowlevel.c
>>
>>
>> Cheers,
>> Ahmad
> 
> 


-- 
Pengutronix e.K.                           |                             |
Steuerwalder Str. 21                       | http://www.pengutronix.de/  |
31137 Hildesheim, Germany                  | Phone: +49-5121-206917-0    |
Amtsgericht Hildesheim, HRA 2686           | Fax:   +49-5121-206917-5555 |