How to incorporate build date/time, firmware versions and board type in Zephyr build for access by code

[BrianW]

Hi

I want to be able to access some build type variables in my C code in a Zephyr project (using west as the build manager) to be able to show them on a screen or in logs (need to identify the exact firmware build and the options used to be able to support customers...)

I have found how to use the Zephr 'VERSION' file to set my firmware versions and then access these as defines in the code.

I would like to do the same for other elements of the build:

- the board type (eg 'nrf5340dk_nrf5340') used for the build

I tried putting a 'boards' section in a snippet to define 'DTS_EXTRA_CPPFLAGS' but it seems these are only passed to the dts tool, not to general C compilation?

  boards:

    cc1medv1_nrf5340:

      append:

        DTS_EXTRA_CPPFLAGS: -DBOARD=cc2-v1

    nrf5340dk_nrf5340:

      append:

        DTS_EXTRA_CPPFLAGS: -DBOARD=nrf5340DK

- the build date/time

I found the config options related to BINDESC such as 

CONFIG_BINDESC_BUILD_DATE_TIME_STRING=y

but, I don't see how to get the generated string in my code?

- the 'snippets' used on the command line for the build (as these affect the binary created!)

? no idea?

[runsiv]

Hi Brian

I'm looking into your issue, however I would be create if you could say which version of NSC you are using? With the release of NCS 2.7 we have switched to Hardware model 2 which now also the default model in Zephyr

If you are planning to use buildesc I would take a look at the buildesc sample which you can find here

Regards

Runar

[BrianW]

output says  NCS Toolchain 2.6.20240304.889616714482.

[Having just suffered to create a model for my board I'm not lookig forward to any 'migration' with 2.7]

Is there a way to get the board name in the code in 2.6?

[runsiv]

I presume you are using custom boards? It should be as simple as using the CONFIG_BOARD macro as seen in for example hello_world

Regards

Runar

[BrianW]

Yes, that works for board type. I don't know why I thought the code sees the KConfig key without the CONFIG_ prefix....

Any ideas for the build time as a define? or the snippets?

[runsiv]

I think maybe the easiest would to do something like 

#define BUILD_DATE __DATE__
#define BUILD_TIME __TIME__

combine that with CONFIG_BOARD gives you 
*** Booting nRF Connect SDK v3.5.99-ncs1-1-1-g80b3bc02d04d ***
Hello World! nrf52840dk_nrf52840
Sep  9 202413:46:28

Regards

Runar

[BrianW]

Ok, I can live with that. -  just means I have to store it in a global string as otherwise its different for each file (due to compile time). But it works for my needs!

thanks 

[runsiv]

Happy to help

Regards

Runar

[BrianW]

Ah, so I remember why I don't like this method... this only updates the build time IF west/cmake decides to recompile the specific C source file that uses it!  Which is often not the case when doing incremental builds...

And I can't find a way to get cmake to always rebuild my specific file; I tried in my root CMakeLists.txt:

file(TOUCH_NOCREATE ${CMAKE_CURRENT_SOURCE_DIR}/ui/uimgr_module.c)

and 

add_custom_target(TARGET ${PROJECT_NAME}
  PRE_BUILD
  COMMAND ${CMAKE_COMMAND} -E touch_nocreate     ${CMAKE_CURRENT_SOURCE_DIR}/ui/uimgr_module.c)

but neither work for a pristine=auto build....

Any ideas?

[runsiv]

Hi

The feedback I got when I asked a bit around would be to use cmake for that, but I guess that would only update every time cmake performs the configuration step, so you would effectively have to do a pristine build to ensure the timestamp is updated. The timestamp would be the same for all C code files  though.  

Create a timestamp variable: https://cmake.org/cmake/help/latest/command/string.html#timestamp

Make it available to the C code: https://cmake.org/cmake/help/latest/command/add_compile_definitions.html

it would not be perfect as you would need to do a pristine build and that takes time it is something

Regards

Runar

[runsiv]

You could also do almost the same as you did here. Just add the part where you touch main each time to trigger a rebuild

cmake_minimum_required(VERSION 3.20.0)
 
 
find_package(Zephyr REQUIRED HINTS $ENV{ZEPHYR_BASE})
project(hello_world)
 
target_sources(app PRIVATE src/main.c)
 
add_custom_target(touch_source
    COMMAND ${CMAKE_COMMAND} -E touch_nocreate ${CMAKE_CURRENT_LIST_DIR}/src/main.c
    COMMENT "Touching source file to force rebuild"
)
 
add_dependencies(app touch_source)

Regards

Runar