Fixes: #57139
Snippets provides the possibility of defining EXTRA_DTC_OVERLAY_FILE and
EXTRA_CONF_FILE in snippets.
Snippets must co-exist with existing infrastructure of
EXTRA_DTC_OVERLAY_FILE and EXTRA_CONF_FILE, and a user specifying a
snippet must be able to specify extra files for adjusting the snippet.
This means that if the following is specified:
`-DSNIPPET=some_snippet -DEXTRA_CONF_FILE=extra.conf`
then `extra.conf` may contain adjustments to the snippet.
Similar to sysbuild. Imagine a sysbuild controlled image uses a default
snippet for building, by ensuring that any extra
`-D<image>_EXTRA_CONF_FILE=extra.conf` arguments takes precedence over
the snippet we allow users to make adjustments if they need.
This commit introduces a snippets scope where snippet scoped variables
can be set with `zephyr_set()` and then `zephyr_get()` will take the
snippet scoped variables into consideration before returning.
Adjust calls to `zephyr_get(EXTRA_DTC_OVERLAY_FILE)` and
`zephyr_get(EXTRA_CONF_FILE)` to use `MERGE` to ensure all scopes are
considered.
Signed-off-by: Torsten Rasmussen <Torsten.Rasmussen@nordicsemi.no>
Add a new script, snippets.py, which is responsible for searching
SNIPPET_ROOT for snippet definitions, validating them, and informing
the build system about what needs doing as a result.
Use this script in snippets.cmake to:
- validate any discovered snippet.yml files
- error out on undefined snippets
- add a 'snippets' build system target that prints all snippet
names (analogous to 'boards' and 'shields' targets)
- handle any specific build system settings properly,
by include()-ing a file it generates
With this patch, you can define or extend a snippet in a snippet.yml
file anywhere underneath a directory in SNIPPET_ROOT. The snippet.yml
file format has a schema whose initial definition is in a new file,
snippet-schema.yml.
This initial snippet.yml file format supports adding .overlay and
.conf files, like this:
name: foo
append:
DTC_OVERLAY_FILE: foo.overlay
OVERLAY_CONFIG: foo.conf
boards:
myboard:
append:
DTC_OVERLAY_FILE: myboard.overlay
OVERLAY_CONFIG: myboard.conf
/my-regular-expression-over-board-names/:
append:
DTC_OVERLAY_FILE: myregexp.overlay
OVERLAY_CONFIG: myregexp.conf
(Note that since the snippet feature is intended to be extensible, the
same snippet name may appear in multiple files throughout any
directory in SNIPPET_ROOT, with each addition augmenting prior ones.)
This initial syntax aligns with the following snippet design goals:
- extensible: you can add board-specific support for an existing
snippet in another module
- able to combine multiple types of configuration: we can now apply a
.overlay and .conf at the same time
- specializable: this allows you to define settings that only apply
to a selectable set of boards (including with regular expression
support for matching against multiple similar boards that follow
a naming convention)
- DRY: you can use regular expressions to apply the same snippet
settings to multiple boards like this: /(board1|board2|...)/
This patch is not trying to design and implement everything up front.
Additional features can and will be added to the snippet.yml format
over time; using YAML as a format allows us to make
backwards-compatible extensions as needed.
Signed-off-by: Marti Bolivar <marti.bolivar@nordicsemi.no>
Basic things needed to integrate the new 'snippets' feature into the
build system. The main CMake variable which controls snippets is
SNIPPET. It is a whitespace-or-semicolon-separated list of snippet
names.
- Add minimal new cmake module for processing snippets. This just has
basic infrastructure for processing a SNIPPET variable into
SNIPPET_AS_LIST, and warning the user if they try to change it too
late.
- Integrate the new module into the build system, via
zephyr_default.cmake
This is anologous to the shields and boards modules' boilerplate and
input variables.
Signed-off-by: Marti Bolivar <marti.bolivar@nordicsemi.no>
