change the carrier board and device tree for Jetson Nano

[danny1209]

Hi all,
this repository works fine for my standard jetson nano devkit from nvidia.
now I change the carrier board, that means the corresponding device tree must also be changed.
I find the device tree are in this folder:
/../tegra-demo-distro/build/tmp/work-shared/jetson-nano-devkit-emmc/kernel-source/nvidia/platform/t210/porg/kernel-dts

so I replace the files here with my own device tree files, espacially the file "tegra210-p3448-0002-p3449-0000-b00.dts"
Everytime when i rerun the command "bitbake demo-image-full", it just skiped all the changed files.
therefore I want to know how to only rebuild and install this part in image? thanks for any help.

Best regard
Daniel

[ichergui]

Hello @danny1209
Did you add the rule in the Makefile to generate the .dtb file ?
Check first in the linux-tegra work directory if you are able to see your new dtb file

[danny1209]

hi @ichergui
yes I have Makefile, but no new dtb files are generated.

[danny1209]

I used "bitbake -c cleansstate virtual/kernel" to remove the existed kernel.
after that I changed the files in /tegra-demo-distro/build/workspace/sources/linux-tegra/nvidia/platform/t210/porg/kernel-dts
and rebuild it with bitbake demo-image-full, but in images I only get a part of the files. original was 43, now only 17

of course without this file and failed.

any idea?

[dwalkes]

after that I changed the files in /tegra-demo-distro/build/workspace/sources/linux-tegra/nvidia/platform/t210/porg/kernel-dts

I don't think you'll want to hack on that content directly. I'd suggest something like the responses in https://stackoverflow.com/questions/68222619/update-custom-device-tree-on-yocto using a bbappend on the linux-tegra kernel recipe. Ridgerun also has a page at https://developer.ridgerun.com/wiki/index.php?title=Yocto_Support_for_NVIDIA_Jetson_Platforms_-_Additional_Topics but it looks a bit out of date with the devicetree paths.

Regarding your test here I suspect you can't just rename the previous build/tmp/work-shared/jetson-nano-devkit-emmc directory and get the same content there with a new build after cleansstate, if this is what you did.

[danny1209]

hi @dwalkes,
thanks for you reply.
the first suggestion seems very complicated.
I tried the second suggestion with devtool modify virtual/kernel, and change the source code in workplace, not in the tmp directory.
Regarding the names, I just wanted to save the old imagefiles and compare them with the new generated directory.
Therefore I found the difference, rebuild just generated only part of the imagefiles, which are genereted from the first time.
also because of this, the final image can not be created successfully.

[danny1209]

Update: it works!
the original image folder "jetson-nano-devkit-emmc" should not be renamed.