0cfb5549b3
Adds functionality to the kconfig infrastructure to merge additional
configuration fragment files to the main configuration file of
kconfig packages, using support/kconfig/merge_config.sh
Typical use-case is when you want your configuration to be
kept in sync with an upstream (def)config file, but do require
some minor local modifications.
Disables -update-config and -update-defconfig targets when
fragment files are set.
[Thomas: take into account comments made by Arnout:
- Minor fixes in the documentation changes
- Add @ before the tests done in the $(1)-update-config and
$(1)-update-defconfig targets.]
Signed-off-by: Floris Bos <bos@je-eigen-domein.nl>
Tested-by: Arnout Vandecappelle (Essensium/Mind) <arnout@mind.be>
Tested-by: Gergely Imreh <imrehg@gmail.com>
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>
68 lines
2.9 KiB
Plaintext
68 lines
2.9 KiB
Plaintext
// -*- mode:doc; -*-
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// vim: set syntax=asciidoc:
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=== Infrastructure for packages using kconfig for configuration files
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A popular way for a software package to handle user-specified
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configuration is +kconfig+. Among others, it is used by the Linux
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kernel, Busybox, and Buildroot itself. The presence of a .config file
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and a +menuconfig+ target are two well-known symptoms of kconfig being
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used.
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Buildroot features an infrastructure for packages that use kconfig for
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their configuration. This infrastructure provides the necessary logic to
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expose the package's +menuconfig+ target as +foo-menuconfig+ in
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Buildroot, and to handle the copying back and forth of the configuration
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file in a correct way.
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The +kconfig-package+ infrastructure is based on the +generic-package+
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infrastructure. All variables supported by +generic-package+ are
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available in +kconfig-package+ as well. See
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xref:generic-package-reference[] for more details.
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In order to use the +kconfig-package+ infrastructure for a Buildroot
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package, the minimally required lines in the +.mk+ file, in addition to
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the variables required by the +generic-package+ infrastructure, are:
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------------------------------
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FOO_KCONFIG_FILE = reference-to-source-configuration-file
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$(eval $(kconfig-package))
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------------------------------
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This snippet creates the following make targets:
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* +foo-menuconfig+, which calls the package's +menuconfig+ target
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* +foo-update-config+, which copies the configuration back to the
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source configuration file. It is not possible to use this target
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when fragment files are set.
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* +foo-update-defconfig+, which copies the configuration back to the
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source configuration file. The configuration file will only list the
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options that differ from the default values. It is not possible to
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use this target when fragment files are set.
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and ensures that the source configuration file is copied to the build
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directory at the right moment.
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In addition to these minimally required lines, several optional variables can
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be set to suit the needs of the package under consideration:
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* +FOO_KCONFIG_EDITORS+: a space-separated list of kconfig editors to
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support, for example 'menuconfig xconfig'. By default, 'menuconfig'.
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* +FOO_KCONFIG_FRAGMENT_FILES+: a space-separated list of configuration
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fragment files that are merged to the main configuration file.
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Fragment files are typically used when there is a desire to stay in sync
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with an upstream (def)config file, with some minor modifications.
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* +FOO_KCONFIG_OPTS+: extra options to pass when calling the kconfig
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editors. This may need to include '$(FOO_MAKE_OPTS)', for example. By
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default, empty.
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* +FOO_KCONFIG_FIXUP_CMDS+: a list of shell commands needed to fixup the
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configuration file after copying it or running a kconfig editor. Such
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commands may be needed to ensure a configuration consistent with other
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configuration of Buildroot, for example. By default, empty.
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