The $srctree environment variable gives the path relative to which
'(o)source' statements work (the current directory is used if $srctree
is unset). It is set to $ZEPHYR_BASE in cmake/kconfig.cmake, so there's
no need to qualify the source of Kconfig.zephyr in sample Kconfig files
(or in external projects).
All 'source's in Zephyr assume that the Zephyr root directory is used as
the srctree as well, and would break otherwise.
Remove the $(ZEPHYR_BASE)s to make it clearer that all 'source'
statements work relative to the Zephyr root. There was some user
confusion on IRC.
Also explain how things work in the documentation.
Signed-off-by: Ulf Magnusson <Ulf.Magnusson@nordicsemi.no>
With the new Kconfig preprocessor (described in
https://github.com/torvalds/linux/blob/master/Documentation/kbuild/
kconfig-macro-language.txt), the syntax for expanding environment
variables is $(FOO) rather than $FOO.
$(FOO) is a general preprocessor variable expansion, which falls back to
environment variables if the variable isn't set (like in Make). It can
also be used in prompts, 'comment's, etc.
The old syntax will probably be supported forever in Kconfiglib for
backwards compatibility, but might as well make it consistent now that
people might start using the preprocessor more.
Signed-off-by: Ulf Magnusson <Ulf.Magnusson@nordicsemi.no>
Update the documentation to say that earlier defaults are preferred,
while explaining Kconfig.defconfig files.
Keep the section that covered the Zephyr prefer-later-defaults patch as
documentation for the behavior having changed. It will be linked in a
warning later.
Also add documentation explaining how to configure choices, including
using multiple definition locations to change a choice 'default'.
Document that 'range's can be added/overriden as well. This works
reliably now.
Signed-off-by: Ulf Magnusson <Ulf.Magnusson@nordicsemi.no>
This commit gets rid of the 'option env="ENV_VAR"' bounce symbols.
"$FOO" now expands directly to the value of the environment variable
FOO, instead of to the value of the Kconfig symbol FOO.
This change is likely to soon appear in the C tools as well. Those
'option env' symbols always seemed kinda pointless, and have broken
dependency handling due to forcing symbol evaluation during parsing,
before all the symbols have even been seen.
Compatibility with the C tools could be retained by naming all
'option env' symbols the same as the environment variable they
reference.
This commit also updated the Zephyr documentation to explain the new
behavior. It's relevant for $ZEPHYR_BASE and out-of-tree Kconfig
extensions.
Commit message from Kconfiglib (cbf32e29a130d)
==============================================
Make "$FOO" directly reference the environment variable $FOO in e.g.
'source' statements, instead of the symbol FOO. Use os.path.expandvars()
to expand strings (which preserves "$FOO" as-is if no environment
variable FOO exists).
This gets rid of the 'option env' "bounce" symbols, which are mostly
just spam and are buggy in the C tools (dependencies aren't always
respected, due to parsing and evaluation getting mixed up). The same
change will probably appear soon in the C tools as well.
Keep accepting 'option env' to preserve some backwards compatibility,
but ignore it when expanding strings. For compatibility with the C
tools, bounce symbols will need to be named the same as the environment
variables they reference (which is the case for the Linux kernel).
This is a compatibility break, so the major version will be bumped to 6
at the next release.
The main motivation for adding this now is to allow recording properties
on each MenuNode in a clean way. 'option env' symbols interact badly
with delayed dependency propagation.
Side note: I have a feeling that recording environment variable values
might be redundant to trigger rebuilds if sync_deps() is run at each
compile. It should detect all changes to symbol values due to
environment variables changing value.
Signed-off-by: Ulf Magnusson <Ulf.Magnusson@nordicsemi.no>
The APPLICATION_BASE variable in the example Kconfig file was copied
in from an (out of tree) application which relied on it during the
Kbuild days, but it's actually not needed by the CMake build system
and should be removed.
Signed-off-by: Marti Bolivar <marti@opensourcefoundries.com>
Fix a few issues related to the description of an application's
CMakeLists.txt file, and how that relates to its configuraiton.
Make sure the section "Application CMakeLists.txt" appears under the
parent "CMake" section, instead of on its own. The order in which
lines appear in the application CMakeLists.txt is important, and
that's not coming through clearly, so try to improve that. Document
how the values for BOARD and CONF_FILE are determined by
boilerplate.cmake here. Also document usage of KCONFIG_ROOT, as its
Kbuild-based equivalent is something that users ask about.
Merge some content from the following section "Application
Configuration" into the appropriate places, to keep the document flow
working. Add references in "Application Configuration" to definitions
provided previously in the document, for clarity.
Signed-off-by: Marti Bolivar <marti@opensourcefoundries.com>
Ulf Magnusson