Hi Ilias,
On Mon, 1 Nov 2021 at 01:05, Ilias Apalodimas ilias.apalodimas@linaro.org wrote:
On Mon, 1 Nov 2021 at 03:19, Simon Glass sjg@chromium.org wrote:
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
The example here might be a bit off and we might need this for int related values. Was this function handle_wibble() supposed to return an int or not? We could shield the linker easier here without adding macros. Something along the lines of static void handle_wibble(void) { #ifdef CONFIG_WIBBLE int val = CONFIG_WIBBLE_ADDR; #endif }
In that case you don't an extra ifdef to call handle_wibble(). Personally I find this easier to read.
But how does that help with the problem here? I am trying to avoid using preprocessor macros in this case.
Regards, Simon
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 0 if CONFIG_WIBBLE is not defined, and CONFIG_WIBBLE_ADDR if it is. 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.
Signed-off-by: Simon Glass sjg@chromium.org
include/linux/kconfig.h | 18 ++++++++++++++++++ scripts/config_whitelist.txt | 1 + 2 files changed, 19 insertions(+)
diff --git a/include/linux/kconfig.h b/include/linux/kconfig.h index a1d1a298426..119c698a158 100644 --- a/include/linux/kconfig.h +++ b/include/linux/kconfig.h @@ -59,6 +59,18 @@ */ #define CONFIG_VAL(option) config_val(option)
+/* This use a similar mechanism to config_enabled() above */ +#define config_opt_enabled(cfg, opt_cfg) _config_opt_enabled(cfg, opt_cfg) +#define _config_opt_enabled(cfg_val, opt_value) \
__config_opt_enabled(__ARG_PLACEHOLDER_##cfg_val, opt_value)+#define __config_opt_enabled(arg1_or_junk, arg2) \
___config_opt_enabled(arg1_or_junk arg2, 0)+#define ___config_opt_enabled(__ignored, val, ...) val
+/* Evaluates to 0 if option is not defined, int_option if it is defined */ +#define IF_ENABLED_INT(option, int_option) \
config_opt_enabled(option, int_option)/*
- Count number of arguments to a variadic macro. Currently only need
- it for 1, 2 or 3 arguments.
@@ -113,5 +125,11 @@ #define CONFIG_IS_ENABLED(option, ...) \ __concat(__CONFIG_IS_ENABLED_, __count_args(option, ##__VA_ARGS__)) (option, ##__VA_ARGS__)
+/*
- Evaluates to 0 if SPL_/TPL_/option is not defined, SPL_/TPL_int_option if it
- is defined
- */
+#define CONFIG_IF_ENABLED_INT(option, int_option) \
CONFIG_IS_ENABLED(option, (CONFIG_VAL(int_option)), (0))#endif /* __LINUX_KCONFIG_H */ diff --git a/scripts/config_whitelist.txt b/scripts/config_whitelist.txt index 022a27288c9..f9d9f4a9cfe 100644 --- a/scripts/config_whitelist.txt +++ b/scripts/config_whitelist.txt @@ -609,6 +609,7 @@ CONFIG_ICS307_REFCLK_HZ CONFIG_IDE_PREINIT CONFIG_IDE_RESET CONFIG_IDE_SWAP_IO +CONFIG_IF_ENABLED_INT CONFIG_IMA CONFIG_IMX CONFIG_IMX6_PWM_PER_CLK -- 2.33.1.1089.g2158813163f-goog
Regards /Ilias