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https://github.com/AsahiLinux/u-boot
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097ff01fb9
At present if an optional Kconfig value needs to be used it must be
bracketed by #ifdef. For example, with this Kconfig setup:
config WIBBLE
bool "Support wibbles, the world needs more wibbles"
config WIBBLE_ADDR
hex "Address of the wibble"
depends on WIBBLE
then the following code must be used:
#ifdef CONFIG_WIBBLE
static void handle_wibble(void)
{
int val = CONFIG_WIBBLE_ADDR;
...
}
#endif
static void init_machine()
{
...
#ifdef CONFIG_WIBBLE
handle_wibble();
#endif
}
Add a new IF_ENABLED_INT() to help with this. So now it is possible to
write, without #ifdefs:
static void handle_wibble(void)
{
int val = IF_ENABLED_INT(CONFIG_WIBBLE, CONFIG_WIBBLE_ADDR);
...
}
static void init_machine()
{
...
if (IS_ENABLED(CONFIG_WIBBLE))
handle_wibble();
}
The value will be CONFIG_WIBBLE_ADDR if CONFIG_WIBBLE is defined and will
produce a build error if not.. This allows us to reduce the use of #ifdef
in the code, ensuring that the compiler still checks the code even if it
is not ultimately used for a particular build.
Add a CONFIG_IF_ENABLED_INT() version as well.
If an attempt is made to use a value that does not exist (i.e. when the
conditional is not enabled), an error about a non-existing function is
generated, e.g.:
common/bloblist.c:447: undefined reference to `invalid_use_of_IF_ENABLED_INT'
Signed-off-by: Simon Glass <sjg@chromium.org>
155 lines
5.7 KiB
C
155 lines
5.7 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, def_val) _config_enabled(cfg, def_val)
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#define _config_enabled(value, def_val) __config_enabled(__ARG_PLACEHOLDER_##value, def_val)
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#define __config_enabled(arg1_or_junk, def_val) ___config_enabled(arg1_or_junk 1, def_val)
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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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#define IS_ENABLED(option) config_enabled(option, 0)
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/*
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* U-Boot add-on: Helper macros to reference to different macros (prefixed by
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* CONFIG_, CONFIG_SPL_, CONFIG_TPL_ or CONFIG_TOOLS_), depending on the build
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* context.
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*/
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#ifdef USE_HOSTCC
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#define _CONFIG_PREFIX TOOLS_
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#elif 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_TOOLS_FOO if USE_HOSTCC is defined,
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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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* This uses a similar mechanism to config_enabled() above. If cfg is enabled,
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* it resolves to the value of opt_cfg, otherwise it resolves to def_val
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*/
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#define config_opt_enabled(cfg, opt_cfg, def_val) _config_opt_enabled(cfg, opt_cfg, def_val)
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#define _config_opt_enabled(cfg_val, opt_value, def_val) \
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__config_opt_enabled(__ARG_PLACEHOLDER_##cfg_val, opt_value, def_val)
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#define __config_opt_enabled(arg1_or_junk, arg2, def_val) \
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___config_opt_enabled(arg1_or_junk arg2, def_val)
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#define ___config_opt_enabled(__ignored, val, ...) val
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#ifndef __ASSEMBLY__
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/*
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* Detect usage of a the value when the conditional is not enabled. When used
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* in assembly context, this likely produces a assembly error, or hopefully at
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* least something recognisable.
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*/
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long invalid_use_of_IF_ENABLED_INT(void);
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#endif
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/* Evaluates to int_option if option is defined, otherwise a build error */
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#define IF_ENABLED_INT(option, int_option) \
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config_opt_enabled(option, int_option, invalid_use_of_IF_ENABLED_INT())
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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), 0)) (case1, case0)
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/*
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* CONFIG_IS_ENABLED(FOO) expands to
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* 1 if USE_HOSTCC is defined and CONFIG_TOOLS_FOO is set to 'y',
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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 USE_HOSTCC is defined and CONFIG_TOOLS_FOO is set to 'y',
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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 USE_HOSTCC is defined and CONFIG_TOOLS_FOO is set to 'y',
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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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#ifndef __ASSEMBLY__
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/*
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* Detect usage of a the value when the conditional is not enabled. When used
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* in assembly context, this likely produces a assembly error, or hopefully at
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* least something recognisable.
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*/
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long invalid_use_of_CONFIG_IF_ENABLED_INT(void);
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#endif
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/*
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* Evaluates to SPL_/TPL_int_option if SPL_/TPL_/option is not defined,
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* otherwise build error
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*/
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#define CONFIG_IF_ENABLED_INT(option, int_option) \
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CONFIG_IS_ENABLED(option, (CONFIG_VAL(int_option)), \
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(invalid_use_of_CONFIG_IF_ENABLED_INT()))
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#endif /* __LINUX_KCONFIG_H */
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