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![Rasmus Villemoes](/assets/img/avatar_default.png)
This adds a bunch of preprocessor magic to extend the capabilities of CONFIG_IS_ENABLED. The existing semantics of CONFIG_IS_ENABLED(FOO) expanding to a 1 or 0 (depending on build context and the defined-ness or not of the appropriate CONFIG_FOO/CONFIG_SPL_FOO/CONFIG_TPL_FOO) are of course preserved. With this, one is also allowed a two-argument form CONFIG_IS_ENABLED(FOO, (something)) which expands to something precisely when CONFIG_IS_ENABLED(FOO) would expand to 1, and expands to nothing otherwise. It is, in other words, completely equivalent to the three lines #if CONFIG_IS_ENABLED(FOO) something #endif The second argument must be parenthesized in order to allow any tokens, including a trailing comma, to appear - one use case for this is precisely to make it a bit more ergonomic to build an array and only include certain items depending on .config. That should increase both readability and not least "git grep"ability. A third variant is also introduced, CONFIG_IS_ENABLED(FOO, (xxx), (yyy)) which corresponds to #if CONFIG_IS_ENABLED(FOO) xxx #else yyy #endif Signed-off-by: Rasmus Villemoes <rasmus.villemoes@prevas.dk> Reviewed-by: Simon Glass <sjg@chromium.org> Signed-off-by: Simon Glass <sjg@chromium.org>
111 lines
3.8 KiB
C
111 lines
3.8 KiB
C
#ifndef __LINUX_KCONFIG_H
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#define __LINUX_KCONFIG_H
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#include <generated/autoconf.h>
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/*
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* Helper macros to use CONFIG_ options in C/CPP expressions. Note that
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* these only work with boolean and tristate options.
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*/
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/*
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* Getting something that works in C and CPP for an arg that may or may
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* not be defined is tricky. Here, if we have "#define CONFIG_BOOGER 1"
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* we match on the placeholder define, insert the "0," for arg1 and generate
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* the triplet (0, 1, 0). Then the last step cherry picks the 2nd arg (a one).
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* When CONFIG_BOOGER is not defined, we generate a (... 1, 0) pair, and when
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* the last step cherry picks the 2nd arg, we get a zero.
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*/
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#define __ARG_PLACEHOLDER_1 0,
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#define config_enabled(cfg) _config_enabled(cfg)
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#define _config_enabled(value) __config_enabled(__ARG_PLACEHOLDER_##value)
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#define __config_enabled(arg1_or_junk) ___config_enabled(arg1_or_junk 1, 0)
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#define ___config_enabled(__ignored, val, ...) val
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/*
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* IS_ENABLED(CONFIG_FOO) evaluates to 1 if CONFIG_FOO is set to 'y',
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* 0 otherwise.
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*
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*/
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#define IS_ENABLED(option) \
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(config_enabled(option))
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/*
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* U-Boot add-on: Helper macros to reference to different macros
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* (CONFIG_ or CONFIG_SPL_ prefixed), depending on the build context.
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*/
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#if defined(CONFIG_TPL_BUILD)
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#define _CONFIG_PREFIX TPL_
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#elif defined(CONFIG_SPL_BUILD)
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#define _CONFIG_PREFIX SPL_
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#else
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#define _CONFIG_PREFIX
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#endif
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#define config_val(cfg) _config_val(_CONFIG_PREFIX, cfg)
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#define _config_val(pfx, cfg) __config_val(pfx, cfg)
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#define __config_val(pfx, cfg) CONFIG_ ## pfx ## cfg
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/*
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* CONFIG_VAL(FOO) evaluates to the value of
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* CONFIG_FOO if CONFIG_SPL_BUILD is undefined,
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* CONFIG_SPL_FOO if CONFIG_SPL_BUILD is defined.
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* CONFIG_TPL_FOO if CONFIG_TPL_BUILD is defined.
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*/
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#define CONFIG_VAL(option) config_val(option)
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/*
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* Count number of arguments to a variadic macro. Currently only need
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* it for 1, 2 or 3 arguments.
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*/
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#define __arg6(a1, a2, a3, a4, a5, a6, ...) a6
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#define __count_args(...) __arg6(dummy, ##__VA_ARGS__, 4, 3, 2, 1, 0)
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#define __concat(a, b) ___concat(a, b)
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#define ___concat(a, b) a ## b
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#define __unwrap(...) __VA_ARGS__
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#define __unwrap1(case1, case0) __unwrap case1
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#define __unwrap0(case1, case0) __unwrap case0
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#define __CONFIG_IS_ENABLED_1(option) __CONFIG_IS_ENABLED_3(option, (1), (0))
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#define __CONFIG_IS_ENABLED_2(option, case1) __CONFIG_IS_ENABLED_3(option, case1, ())
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#define __CONFIG_IS_ENABLED_3(option, case1, case0) \
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__concat(__unwrap, config_enabled(CONFIG_VAL(option))) (case1, case0)
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/*
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* CONFIG_IS_ENABLED(FOO) expands to
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* 1 if CONFIG_SPL_BUILD is undefined and CONFIG_FOO is set to 'y',
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* 1 if CONFIG_SPL_BUILD is defined and CONFIG_SPL_FOO is set to 'y',
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* 1 if CONFIG_TPL_BUILD is defined and CONFIG_TPL_FOO is set to 'y',
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* 0 otherwise.
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*
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* CONFIG_IS_ENABLED(FOO, (abc)) expands to
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* abc if CONFIG_SPL_BUILD is undefined and CONFIG_FOO is set to 'y',
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* abc if CONFIG_SPL_BUILD is defined and CONFIG_SPL_FOO is set to 'y',
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* abc if CONFIG_TPL_BUILD is defined and CONFIG_TPL_FOO is set to 'y',
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* nothing otherwise.
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*
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* CONFIG_IS_ENABLED(FOO, (abc), (def)) expands to
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* abc if CONFIG_SPL_BUILD is undefined and CONFIG_FOO is set to 'y',
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* abc if CONFIG_SPL_BUILD is defined and CONFIG_SPL_FOO is set to 'y',
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* abc if CONFIG_TPL_BUILD is defined and CONFIG_TPL_FOO is set to 'y',
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* def otherwise.
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*
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* The optional second and third arguments must be parenthesized; that
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* allows one to include a trailing comma, e.g. for use in
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*
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* CONFIG_IS_ENABLED(ACME, ({.compatible = "acme,frobnozzle"},))
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*
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* which adds an entry to the array being defined if CONFIG_ACME (or
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* CONFIG_SPL_ACME/CONFIG_TPL_ACME, depending on build context) is
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* set, and nothing otherwise.
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*/
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#define CONFIG_IS_ENABLED(option, ...) \
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__concat(__CONFIG_IS_ENABLED_, __count_args(option, ##__VA_ARGS__)) (option, ##__VA_ARGS__)
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#endif /* __LINUX_KCONFIG_H */
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