zephyr/Kconfig.zephyr

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# Kconfig - general configuration options
#
# Copyright (c) 2014-2015 Wind River Systems, Inc.
# Copyright (c) 2016 Intel Corporation
#
# SPDX-License-Identifier: Apache-2.0
#
Kconfig: Use the first default with a satisfied condition Up until now, Zephyr has patched Kconfig to use the last 'default' with a satisfied condition, instead of the first one. I'm not sure why the patch was added (it predates Kconfiglib), but I suspect it's related to Kconfig.defconfig files. There are at least three problems with the patch: 1. It's inconsistent with how Kconfig works in other projects, which might confuse newcomers. 2. Due to oversights, earlier 'range' properties are still preferred, as well as earlier 'default' properties on choices. In addition to being inconsistent, this makes it impossible to override 'range' properties and choice 'default' properties if the base definition of the symbol/choice already has 'range'/'default' properties. I've seen errors caused by the inconsistency, and I suspect there are more. 3. A fork of Kconfiglib that adds the patch needs to be maintained. Get rid of the patch and go back to standard Kconfig behavior, as follows: 1. Include the Kconfig.defconfig files first instead of last in Kconfig.zephyr. 2. Include boards/Kconfig and arch/<arch>/Kconfig first instead of last in arch/Kconfig. 3. Include arch/<arch>/soc/*/Kconfig first instead of last in arch/<arch>/Kconfig. 4. Swap a few other 'source's to preserve behavior for some scattered symbols with multiple definitions. Swap 'source's in some no-op cases too, where it might match the intent. 5. Reverse the defaults on symbol definitions that have more than one default. Skip defaults that are mutually exclusive, e.g. where each default has an 'if <some board>' condition. They are already safe. 6. Remove the prefer-later-defaults patch from Kconfiglib. Testing was done with a Python script that lists all Kconfig symbols/choices with multiple defaults, along with a whitelist of fixed symbols. The script also verifies that there are no "unreachable" defaults hidden by defaults without conditions As an additional test, zephyr/.config was generated before and after the change for several samples and checked to be identical (after sorting). This commit includes some default-related cleanups as well: - Simplify some symbol definitions, e.g. where a default has 'if FOO' when the symbol already has 'depends on FOO'. - Remove some redundant 'default ""' for string symbols. This is the implicit default. Piggyback fixes for swapped ranges on BT_L2CAP_RX_MTU and BT_L2CAP_TX_MTU (caused by confusing inconsistency). Piggyback some fixes for style nits too, e.g. unindented help texts. Signed-off-by: Ulf Magnusson <Ulf.Magnusson@nordicsemi.no>
2018-07-30 16:57:47 +08:00
# Include these first so that any properties (e.g. defaults) below can be
# overriden in *.defconfig files (by defining symbols in multiple locations).
# After merging all the symbol definitions, Kconfig picks the first property
# (e.g. the first default) with a satisfied condition.
#
# Board defaults should be parsed before SoC defaults, because boards usually
# overrides SoC values.
#
# $ENV_VAR_ARCH and $ENV_VAR_BOARD_DIR might be glob patterns
gsource "$ENV_VAR_BOARD_DIR/Kconfig.defconfig"
gsource "arch/$ENV_VAR_ARCH/soc/*/Kconfig.defconfig"
source "arch/Kconfig"
source "kernel/Kconfig"
source "dts/Kconfig"
source "drivers/Kconfig"
source "misc/Kconfig"
source "lib/Kconfig"
source "subsys/Kconfig"
source "ext/Kconfig"
source "tests/Kconfig"