nrf9160 - configuring with west and different board always results in the same zeyhyr_settings.txt

[stes]

Hi DevZone Team,

 when I use west to configure a project, build/zephyr_settings.txt always contains

"BOARD_ROOT":"/home/user/test/nrf"
"DTS_ROOT":"/home/user/test/nrf"

I would assume that when I configure with "west build -t nrf9160dk_nrf9160ns" the resulting build/zephyr_settings.txt contains:

"BOARD_ROOT":"/home/user/test/zephyr"
"DTS_ROOT":"/home/user/test/zephyr"

as the board nrf9160dk_nrf9160 is to be found in /home/user/test/zephyr/boards/arm

Could you explain why BOARD_ROOT is pointing to the nrf directory?

Regards

Stefan

[Didrik Rokhaug]

Hi,

A West module can have a <module>/zephyr/module.yml file that describes it, as well as integrates it into Zephyr's build system.

Here is the contents of nrf/zephyr/module.yml:

build:
  cmake: .
  kconfig: Kconfig.nrf
  settings:
    board_root: .
    dts_root: .
    module_ext_root: .

As you can see, it sets board_root and dts_root to be the nrf directory.

Best regards,

Didrik

[stes]

Thank you for the quick response. But still I would assume that BOARD_ROOT refers to the correct directory, which would be /zephyr as the board is located in /zephyr/boards/..., not in /nrf/boards

Best

Stefan

[Didrik Rokhaug]

This comment from zephyr/cmake/app/boilerplate.cmake should explain it:

# 'BOARD_ROOT' is a prioritized list of directories where boards may
# be found. It always includes ${ZEPHYR_BASE} at the lowest priority.
zephyr_file(APPLICATION_ROOT BOARD_ROOT)
list(APPEND BOARD_ROOT ${ZEPHYR_BASE})

In other words, nrf/zephyr/module.yml sets the BOARD_ROOT to point to nrf, so the boards defined in nrf is included, in addition to the boards defined in zephyr.