Re: [ptxdist] How to create a board/platform from scratch (specifically iMX8M)

[Alexander Dahl <ada@thorsis.com>]

Hello Mircea,

Am Mittwoch, 2. September 2020, 15:05:45 CEST schrieb Mircea Ciocan:
> Hello everybody, is there a tutorial on creating a configuration for a
> new board starting from scratch, specifically for the iMX8M MCU ?

Not to my knowledge. What we did here for the last two new boards was using 
existing boards as a base and adapting from there.

> As far as I could find there are no public references on how to do it
> from scratch, especially u-Boot integration, image creation and so on.
> If I'm wrong kindly please correct me and point to the documentation.

Integrating an already working U-Boot configuration into ptxdist is not 
especially hard, but it involves some steps and you have different possible 
ways. What I did for the new board we are currently developing was basically 
this:

Get the full U-Boot support running outside of ptxdist, with U-Boot only:

- clone the U-Boot Git tree
- make your own branch based on the last U-Boot release
- you can build with OSELAS.Toolchain already:

PATH="/opt/OSELAS.Toolchain-2019.09.1/arm-v7a-linux-gnueabihf/gcc-9.2.1-
clang-8.0.1-glibc-2.30-binutils-2.32-kernel-5.0-sanitized/bin:${PATH}" 
CROSS_COMPILE=arm-v7a-linux-gnueabihf- CFLAGS='-Wall -Wcast-align' make O=~/
build/u-boot …

For ptxdist integration after your U-Boot image is working:

- save the U-Boot defconfig to the tree or export your .config
- export your changes as patches
- import those patches in your BSP
- activate U-Boot in platformconfig
- choose legacy config and enter the defconfig filename
- or choose kconfig and copy over your exported .config

The hard work is in U-Boot itself, but some hints in the docs could be 
helpful, too.

For development you could also use the `ptxdist local-src` feature of course 
and let ptxdist symlink your U-Boot source tree, this is probably best with 
kconfig based U-Boot config then.

Bonus level: get your U-Boot patches upstream, you won't have to carry them in 
your BSP then. ;-)

(Of course your U-Boot binary image has to go to your target somehow, but 
that's highly dependent on your board and from what memory you want to boot. 
It may involve creating a config for genimage: different topic.)

> Also did anybody ever tried ptxdist with a board holding iMX8M MCU, as
> far as I can see everything is now Yocto, or buildroot (rarely).
> 
> I think it's also because there are practically no sample configurations
> for modern ARM MCUs, buildroot for example comes with a number included
> configurations at least for the NXP EVKs.
> 
> I believe it will be a good idea to include a number of configurations
> for more popular development/evaluation kits, if not in the main
> ptxdist, at least as an add-on package, what is the list opinion ?

See DistroKit. It was already mentioned by Rouven.

HTH & Greets
Alex




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