diff options
authorMasahiro Yamada <>2015-08-12 07:31:42 +0900
committerTom Rini <>2015-08-18 13:46:00 -0400
commit04a5c40601adb007ab064e1aa4a2b5717217457e (patch)
parent29974f773776e40a2cd5563bd7a83fd960651c3f (diff)
kbuild: add a makefile macro useful with per-image config options
Commit e02ee2548afe ("kconfig: switch to single .config configuration") made the configuration itself pretty simple, instead, we lost the way to systematically enable/disable config options for each image independently. Our current strategy is, put entries into Makefile.spl for options we need separate enabling, or once enable the options globally in Kconfig and then undef them in Makefile.uncmd_spl if we do not want to compile the features for SPL at all. Things are getting really messy. Besides, "ifdef CONFIG_SPL_BUILD" are sprinkled everywhere in makefiles. This commit adds a variable to help describe makefile simpler. $(SPL_) evaluates to "SPL_" during the SPL build, while to an empty string during building U-boot proper. So, you can write obj-$(CONFIG_$(SPL_)FOO) += foo.o instead of ifdef CONFIG_SPL_BUILD obj-$(CONFIG_SPL_FOO) += foo.o else obj-$(CONFIG_FOO) += foo.o endif If CONFIG_SPL_FOO does not exist in Kconfig, it is equivalent to ifndef CONFIG_SPL_BUILD obj-$(CONFIG_SPL_FOO) += foo.o endif This is the pattern we often see in our current makefiles. To take advantage of this macro, we should prefix SPL_ for the SPL version of the option when we need independent control between U-boot and SPL. With this naming scheme, I hope our makefiles will be much simplified. It means we want to rename existing config options as follows in the long run: CONFIG_SPL_SERIAL_SUPPORT -> CONFIG_SPL_SERIAL CONFIG_SPL_I2C_SUPPORT -> CONFIG_SPL_I2C CONFIG_SPL_GPIO_SUPPORT -> CONFIG_SPL_GPIO CONFIG_SPL_SPI_SUPPORT -> CONFIG_SPL_SPI CONFIG_SPL_DISABLE_OF_CONTROL -> CONFIG_SPL_OF_CONTROL (inverting the logic) Then drivers/Makefile would be re-worked as follows: obj-$(CONFIG_$(SPL_)SERIAL) += serial/ obj-$(CONFIG_$(SPL_)I2C) += i2c/ obj-$(CONFIG_$(SPL_)GPIO) += gpio/ obj-$(CONFIG_$(SPL_)SPI) += spi/ ... Eventually, SPL-specialized entries in Makefile.spl would go away. Signed-off-by: Masahiro Yamada <> Reviewed-by: Tom Rini <> Reviewed-by: Simon Glass <>
1 files changed, 6 insertions, 0 deletions
diff --git a/scripts/Kbuild.include b/scripts/Kbuild.include
index f02eb37f75..98e09ce5fb 100644
--- a/scripts/Kbuild.include
+++ b/scripts/Kbuild.include
@@ -309,3 +309,9 @@ why = \
echo-why = $(call escsq, $(strip $(why)))
+SPL_ := SPL_
+SPL_ :=
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