Configure your mother board¶

This page gives an example where you are using a SOM supported by Welma but with a different mother board.

This example is based on a SOM sm2s-imx93 and only considers modification of the kernel device tree.

• Copy Welma's machine conf to your layer:

cp meta-welma-sm2s-imx9/conf/machine/sm2s-imx93-mbep5.conf \
   meta-project/conf/machine/sm2s-imx93-custom.conf

• Adjust KERNEL_DEVICETREE to build your own device tree overlay (specific to your mother board):

  KERNEL_DEVICETREE += "msc/imx93/overlay-custom.dtb"
  

• Add this device tree overlay in the kernel recipe:

  meta-project/recipes-kernel/linux/linux-imx_%.bbappend

  FILESEXTRAPATHS:prepend := "${THISDIR}/${PN}:"
  SRC_URI += "file://0001-msc-sm2s-imx93-support-for-custom-board.patch"
  

... and add the patch in meta-project/recipes-kernel/linux/linux-imx/.

• Modify U-Boot to select this overlay at startup:

  diff meta-project/recipes-bsp/u-boot/u-boot-imx/distro-bootcmd.env

  -fdt_overlay_opt=conf-overlay-baseboard-ep5.dtb
  +fdt_overlay_opt=conf-overlay-custom.dtb
  

• Modify the local.conf template:

  diff meta-project/conf/templates/default/local.conf.sample

  -MACHINE ?= "sm2s-imx93-mbep5"
  +MACHINE ?= "sm2s-imx93-custom"