State of BTT Pi and CB1 support

[JohnTheCoolingFan]

Hello. I am taking the task of organizing and performing the BTT Pi and CB1 support update. The plan is to use mainline kernel 6.6 and 6.8 (basically the default sunxi64 config) instead of the BTT fork and use patches to backport kernel patches for drivers and hardware support. The Jira issue is AR-2312, which is a collection of things that will need to be done for this initiative. @Gunjan Gupta @c0rnelius @ag123 @jernej @ALIGMSTEN I'm asking for your help on this, as Igor has said to me that you are more knowledgeable on the state of the board and what it needs.

From what I've found, there has been a PR that upgraded the kernel used for BTT CB1 to 6.1.79 using patches, and there's a discussion on reconstructing or copying the BigTreeTech device tree for 6.6.y and up. The BTT's changes are mostly drivers, device tree and other hardware support and backporting. I think BTT's linux 6.2.y branch should be used as the starting point to determine what board-specific patches and changes are needed. Some of the drivers are already in the 6.6.y (CURRENT) and 6.8.y (EDGE) kernel versions, some are added by armbian, some are only in the vendor's fork.

[c0rnelius]

I've only worked with the BPI-M4-ZERO.

 

My personally opinion on the h616/8 line up is that the focus should be on stable and not LTS. Little to none of the official mainline patches are being back ported and the patches being used currently in LTS are kind of hack-a-noodle patches.

 

For example:

https://lore.kernel.org/linux-arm-kernel/CA+E=qVeMnQNrT8tNnHBnCL2Efy3VjbRAYQGMXstziCThRsiBDw@mail.gmail.com/T/

https://lore.kernel.org/linux-arm-kernel/20240419071450.7aiheeoyq35yjoo7@vireshk-i7/T/

 

The ones being currently used in Armbian I believe are either RFC's or taken from OPI. The thermal patch above is already in 6.9.y.

 

But with that said, if you have any questions feel free to hit me up and if I can, I'll help.

[jernej]

I don't have neither of these boards, but I can help answering any question regarding state of the art drivers in mainline kernel.

[ag123]

@JohnTheCoolingFan neither am I familiar with much of that. I'd just like to say that H618 support evolves out of H616 and the DTS for Orange Pi Zero 3 and Zero 2W is contributed by Andre Przywara from 6.6 mainline kernel.

But that various contributors here worked the DTS further, check in the thread for details.

Note that there are also change in *u-boot* for Orange Pi Zero 3, mainly to add the PMIC and DDR4 support for Orange Pi Zero 3

 

I think some key difference between Orange Pi Zero 2 (H616) vs Orange Pi Zero 3 (H618)  are :

- PMIC the power management IC is different

- Orange Pi Zero 3 uses lpddr4 vs Orange Pi Zero 2 lpddr3

various other 'small' differences and that H618 is after all based on H616 codebase.

 

Hence, my guess is to attempt to use the 6.6 and up mainline kernel and do a rebuild for CB1.

 

One thing I'm not sure is where to configure that so that the build would use the 6.6.x mainline kernel during the build.

It would likely 'not build cleanly' (e.g. without errors) and the build errors especially if the 'old' patches for the same board is applied and those would need to be resolved.

You would take into account the actual hardware differences vs Orange Pi Zero 2 or Orange Pi Zero 3 if after all they are different on the CB1.

 

[JohnTheCoolingFan]

Thanks for your advice, this is really helpful. I am switching the board config to use bananapi sun50iw family, and it looks like most of the changes BTT made are already in the list  of patches for sunxi-6.6 and sunxi-6.7 (the current config doesn't use 6.8 as edge). I'm making an analysis of the differences. The most obvious change that will be needed is to add the dts file, which is already in 6.7 but will need to be backported for 6.6. Although the device tree in the kernel makes a difference between a Pi and CB1 (SoM), which is also used on a Manta (CNC/3d-printing control board with SoM socket for CB1/CB2).