Please provide useful sample for "Board extensions"

[boaks]

I tried to create a Board extension.

That seems to be rather complex. I couldn't find samples else the the tests for cmake.

What I consider to be required:

If the board the extension is based on is defined by

dir: <vendor>/<board>
board.yml: <board>/<target>/<qual>

what must the extension board then follow:

Is it possible to use an other "vendor" as folder name?

What should the build target board be?

<board>/<target>/<qual>/<ext>

<board>/<ext>

I feature with that complexity but no samples is extremely hard to use.

[ljd42]

Hi @boaks ,

I extended the Zephyr Example Application to play with board extension:
https://github.com/ljd42/example-application

It's a shameless integration of what is found under the tests for cmake to the Zephyr example application.

Is it possible to use an other "vendor" as folder name?

I don't think so.
The name of the "extended board" folder under "vendor" can be anything apparently (?)

What should the build target board be?

As you can see in the native/native_sim_boaks folder, the board.yml extends native_sim/native (one) and native_sim/native/64 (two).
Using west build with "west completion" enabled:

(.venv) ➜  example-application git:(main) west build -p -b native_sim/native<TAB>
native_sim/native         native_sim/native/64/two                          
native_sim/native/64      native_sim/native/one        

Hope this helps!

[boaks]

Thanks a lot!
I had a look and I will need to test it.

From your example:

Original board "native_sim" (zephyr/boards/native/native_sim):
vendor: "zephyr"
name: "native_sim"

(It seem to be possible to use a folder name different from the vendor ;-). )

Extended board (prj/boards/native/native_sim_boaks):
name: "one" or "two"

Using west build with "west completion" enabled:

Ah, that's pretty helpful

[ljd42]

From your example:

Original board "native_sim" (zephyr/boards/native/native_sim):
vendor: "zephyr"
name: "native_sim"

(It seem to be possible to use a folder name different from the vendor ;-). )

The folder name refers to the structure boards/<VENDOR>/<board_name>, like here. As you see, the <VENDOR> is native, so this structure is reflected in the example application. See the note mentioned in this section

The vendor: in board.yml is a meta-data field for board.yml. This two "vendors" must ideally be the same, anything else would be confusing. This wasn't always so, LTS 3.7 has many exceptions.

I just checked against main, all those exceptions have disappeared excepted for qemu and native:

[FAIL] zephyr/boards/qemu/cortex_a72/board.yml - Expected vendor 'qemu', got 'raspberrypi'
[FAIL] zephyr/boards/qemu/kvm_arm64/board.yml - Expected vendor 'qemu', got 'arm'
[FAIL] zephyr/boards/qemu/leon3/board.yml - Expected vendor 'qemu', got 'gaisler'
[FAIL] zephyr/boards/qemu/x86/board.yml - Expected vendor 'qemu', got 'intel'
[FAIL] zephyr/boards/qemu/xtensa/board.yml - Expected vendor 'qemu', got 'cdns'
[FAIL] zephyr/boards/qemu/cortex_m0/board.yml - Expected vendor 'qemu', got 'nordic'
[FAIL] zephyr/boards/qemu/cortex_a53/board.yml - Expected vendor 'qemu', got 'arm'
[FAIL] zephyr/boards/qemu/rx/board.yml - Expected vendor 'qemu', got 'renesas'
[FAIL] zephyr/boards/native/nrf_bsim/board.yml - Expected vendor 'native', got 'zephyr'
[FAIL] zephyr/boards/native/native_sim/board.yml - Expected vendor 'native', got 'zephyr'

Let me know if you need additional help!

[boaks]

Thanks again.
I will need some more time to test your sample on "my machine". I guess it will be not before Friday.

[boaks]

I skipped breakfast and tested it ;-).
Your sample works. Unfortunately my "extension" is still not working (I would like to extend circuitdojo/feather_nrf9151).

What irritates me pretty much is the use of terms, for path and meta-data, and the values. In my opinion it's really, really hard to see, what is used when. And what is required or convention.

From Board extensions:

boards/<VENDOR>/plank
├── board.yml
├── plank_<new-qualifiers>_defconfig
└── plank_<new-qualifiers>.dts

From your (working) sample:

boards/native/native_sim_boaks
├── board.yml (extend: native_sim, name: one)
├── native_sim_native_one_defconfig
└── native_sim_native_one.dts

Does the filename "plank_<new-qualifiers>.dts" reflect the "plank" as directory name or "plank" as the name of the extension?
And in your sample "native_sim_native_one" is used, that doesn't reflect neither the directory nor name. Though that works, it makes me feel, the docu isn't well. Is it "<board>_<extension>"?

[boaks]

:-).

I copied the folder "boards/native/native_sim_boaks" into my project, ... and it fails there.
Then I examined the differences, it's the configuration in ./zephyr/module.yaml, which makes it working ...

I guess, the "board_root: .", but it will require some more time and for today I'm finished.

Really big thank you, without your sample there are too many points, which may cause issues or not.