Guide for custom board bringup

[apbr]

Hi,
is there a guide on how to create a new MACHNE for a custom carrier board (Orin NX in this case)?
I'm looking for something that explains how to apply the instructions from the Jetson Module Adaptation and Bring-Up Nvidia guide to the Yocto/meta-tegra world.
I found Creating a custom MACHINE - meta-tegra wiki but it seems lacking a lot of steps.

If such guide does not exist yet, I'd be glad to extend Creating a custom MACHINE - meta-tegra wiki if this is desired.
(As soon as I figured out which steps are required ofc)

I am confident I figured out most steps, which seems to be the following:

• Create a new machine config (Or copy & modify an existing).
• Create a new flashvars file for this machine. (Or copy & modify an existing).
• Add and include the dtsi files that are produced by the Nvidia pinmux Excel sheet.
• Add and use a custom device tree.
• (Optionally) Disable EEPROM usage by modifiying MB2 config which is set in MB2BCT_CFG in flashvars

Do you see anything missing?

What I'm not sure about at the moment is the following:
What should I do with the dtsi files from the pinmux?
Do I just have to append tegra-bootfiles_35.4.1.bb so those files are placed in ${D}${datadir}/tegraflash/ and then change the flashvars file?

• I guess the pinmux.dtsi is what is set in PINMUX_CONFIG.
• gpio.dtsi seems to be included in pinmux.dtsi, so I guess I don't need to specify it anywhere else?
• It seems padvoltage.dtsi is what is set in PMC_CONFIG.

Is this correct?
Is there any other place where I have to place or reference these new dtsis?

[madisongh]

Sounds good overall. It would be great to have more detail in the wiki about this process.

Do I just have to append tegra-bootfiles_35.4.1.bb so those files are placed in ${D}${datadir}/tegraflash/ and then change the flashvars file?

Yeah, something like that. What I've done for my custom machines is to create a new recipe for the config files generated out of the pinmux spreadsheet and have a bbappend for tegra-bootfiles depend on that. The other recipe just fetched the files from a git repo where I stored them after running through the macros in the spreadsheet.

For the flashvars file, I add a bbappend for the tegra-flashvars recipe, which prepends to FILESEXTRAPATHS to get the custom copy of the flashvars file for my new machine.

I haven't gone through this process myself for an Orin-based machine, so I'm not 100% sure about the .dtsi files you're asking about, but from what I can see that looks right.

[madisongh]

Device trees are normally built with the kernel, but we do have a mechanism for providing them from an alternative location. There's an example of using this here. That recipe builds the device trees from sources, but if you have only DTB files, you could just have the recipe directly install those.

[spb06]

Thanks for the response!

I came across the link that you shared and tried it out but still no luck. Yocto builds and I can see my-machine.dtb, padvoltage dtsi, gpio dtsi, and pinmux dtsi in the tar file that gets generated, however, when I flash the board does not boot up completely. My guess is I am close and need to tweak a couple of things to make it work. I am running kirkstone btw.

Essentially, below are the steps I took to add the device tree:

1. added the following to the local.conf:
   PREFERRED_PROVIDER_virtual/dtb = "my_machine-devicetree"
DTBFILE:my_machine = "my_machine.dtb"

2. added the my_machine.dts (decompiled version of the .dtb that the carrier board vendor provided) under recipes-bsp/my_machine-devicetree/files

3. Coped the .bb from here. and changed out the name of the .dts file.

4. Changed the KERNEL_DEVICETREE in my_machine.conf from KERNEL_DEVICETREE ?= "tegra234-p3701-0000-p3737-0000.dtb tegra234-p3701-0004-p3737-0000.dtb" (which was copied over from jetson-agx-orin-devkit.conf) to KERNEL_DEVICETREE ?= ""

My questions:

1. Do I need to edit anything else in the .bb from here?

2. I used the decompiled .dts version of the .dtb that vendor sent me. Is there any way to use the the .dtb instead of the .dts? I tried to change the KERNEL_DEVICETREE in my_machine.conf from KERNEL_DEVICETREE ?= "tegra234-p3701-0000-p3737-0000.dtb tegra234-p3701-0004-p3737-0000.dtb" (which was copied over from jetson-agx-orin-devkit.conf) to KERNEL_DEVICETREE ?= "my_machine.dtb" and placed the my_machine.dtb file in recipes-bsp/my_machine-devicetree/files but the build failed and the error message stated "could not find recipe for target my_machine.dtb".

[madisongh]

As I mentioned above, you should be able to list the .dtb file(s) in the SRC_URI and just install them directly, instead of decompiling/recompiling.

As far as debugging the boot problem goes, monitoring the serial console output during the flashing and boot process, to see where it gets stuck, would be the first step.

[spb06]

Thanks again! I went ahead and tried the following and got the following error:

• Made KERNEL_DEVICETREE ?= "my_machine.dtb" inside my_machine.conf
• Made SRC_URI = " \ file://my_machine.dtb \" inside my_machine-devicetree_1.0.bb (which is a replica of tegrademo-devicetree_1.0.bb)

Error:

make[2]: *** No rule to make target 'arch/arm64/boot/dts/my_machine.dtb'. Stop.
make[1]: *** [build/tmp/work-shared/my_machine/kernel-source/Makefile:1381: my_machine.dtb] Error 2
make: *** [build/tmp/work-shared/my_machine/kernel-source/Makefile:203: __sub-make] Error 2
ERROR: oe_runmake failed
ERROR: Task (poky/../meta-tegra/recipes-kernel/linux/linux-tegra_5.10.bb:do_compile) failed with exit code '1'

Seems like yocto needs to see something more to correctly incorporate my_machine.dtb.

[madisongh]

You'll need to change your recipe to omit the compilation step completely and change the installation step to directly install the pre-compiled DTB files into the right locations.