Customizing the BSP for coprocessor support

To download and start the Cortex®-M33 firmware from U-Boot, the U-Boot command cm33 must be implemented. Also the Linux-kernel needs some features implemented to communicate between the main processors and the coprocessor.

To support customers, Ka-Ro provides the distro feature copro. To add the distro feature to your build, edit the file conf/local.conf in your yocto build directory and add the line:

DISTRO_FEATURES:append = " copro"

Furthermore, some special entries into the device tree are necessary. These are provided by the devicetree overlay karo-copro

To add the karo-copro overlay, the name of the copro-overlay should be added to the appropriate overlays_* variable:

setenv overlays_<baseboard> ${overlays_<baseboard>} karo-copro

If you are working with a TX- module on the TX Mainboard 7 ready-to-use development system, then the setup looks like this:

setenv overlays_mb7 ${overlays_mb7} karo-copro
setenv baseboard mb7

Please note, the variable baseboard must be setup correctly for the overlay to be loaded.