Best practice for custom carrier board

Hello,

we will receive soon our new custom carrier board for the Apalis iMX6D 512MB board.

It is essentially a stripped down version of the Ixora carrier board, but only using Ethernet, CAN 1 and CAN2, 1 USB (host) and one debug RS-232.

All of our development (creating a new Image using yocto) was done on the Ixora V1.1A, and everything runs fine on it.

As soon as I will receive the customized carrier board, I want to start testing my Image and making sure everything will also work fine.

The question I have is about the best way to “adapt” out Image (now running on the Ixora) to the new custom carrier board:

  • Is it enough to customize the device tree by removing any unneeded devices (HDMI, …), then compile it to create a customized .dtb and specify the new .dtb inside the u-boot bootloader?

  • Or should I also remove some features from the kernel ?

  • Any other better way to do it ?

We don’t have any specific time requirements for loading the kernel (the kernel load time using the Ixora is perfectly fine).

If it is just enough to customize the device tree, and not changing the standard kernel, I would prefer this option. Provided the Kernel does not complain if it does not find the missing devices.

Thanks in advance for any help.

Nicola

In general - device tree customization should be sufficient.
Moreover since you are only stripping down peripherals but do not changing what are remains - even the standard Toradex Linux image should boot OK. Yes it will complain about missing peripherals but will be functional.
However Kernel/Root FS customization can save you some resources like RAM/Flash/boot time.

So when you get a new carrier board i’d recommend

  • Try to boot standard Toradex linux
  • Compile a new DTB. Copy it to boot partition (/media/mmcblk0p1 if using Linux or mmc 0:1 if using UBoot)
  • Update fdt_file environment variable at U-Boot.
  • Boot Linux and analyze boot log for possible issues.

Hello Alex,

thank you for your answer.

I will follow your advice and then create a customized device tree.

Eventually I will integrate the new device tree into my yocto project, so to have at the end my Image with customized DTB.

Thanks,
Nicola

hi Nicola,
you are welcome.