Refer to Simon's question, too:
http://lists.denx.de/pipermail/u-boot/2015-July/219598.html
Since U-boot introduced SPL (not since Kconfig),
enabling features for U-boot and SPL independently is always a PITA.
- decide if each feature should be supported for SPL or not
- Add CONFIG_SPL_FRED_SUPPORT into Makefile.spl
- Add #undef include/config_uncmd_spl.h to disable features
we do not want to support on SPL
- Add "ifdef CONFIG_SPL_BUILD ... endif" here and there to adjust things
- Add "#ifdef CONFIG_SPL_BUILD ... #endif" here and there to fix things up
Things are getting more and more crappy.
When U-boot switched to Kconfig, first I introduced separate .config
(.config, spl/.config, tpl/.config) to clean up them.
But it turned out to be a pain.
So, I believe the current single .config is much better.
But I also admit we need something systematic to subdue our PITA.
One possibility is to support "spl-y" in makefiles.
(This idea is cribbed from barebox.)
obj-$(CONFIG_FOO) += foo.o
spl-$(CONFIG_SPL_FOO) += foo.o
is cleaner than
ifdef CONFIG_SPL_BUILD
obj-$(CONFIG_SPL_FOO) += foo.o
else
obj-$(CONFIG_FOO) += foo.o
endif
It is a nice improvement in makefile side.
But we still need to do something with C files.
Another option is something like
CONFIG_FOO=yyn (yes for U-boot, yes for SPL, no for TPL)
To achieve this, I think a big operation is needed in Kconfig core.
I cannot do that.
(Of course, Patches are welcome if someone else can do that.)
So, I was thinking of something different.
My idea was inspired by IS_ENABLED() macro in include/linux/kconfig.h.
Linux defines different macros for built-in and module,
and it is possible to write
#if IS_ENABLED(CONFIG_FOO)
...
#endif
instead of
#if defined(CONFIG_FOO) || defined(CONFIG_FOO_MODULE)
...
#endif
So, I'd like to propose new macros to write code like
#if CONFIG_IS_ENABLED(FOO)
...
#endif
instead of
#if (!defined(CONFIG_SPL_BUILD) && defined(CONFIG_FOO)) || \
(defined(CONFIG_SPL_BUILD) && defined(CONFIG_SPL_FOO))
...
#endif
I hope this series will make our life easier.
I know scripts/basic/fixdep.c must be tweaked for generating correct
.cmd files.
But I think this series is enough to show my intention.
Looks nice or not?
Comments are welcome.
Masahiro Yamada (2):
kbuild: add a makefile macro useful with per-image config options
linux/kconfig.h: add C macros useful for per-image config options
include/linux/kconfig.h | 48 ++++++++++++++++++++++++++++++++++++++++++++++++
scripts/Kbuild.include | 3 +++
2 files changed, 51 insertions(+)
--
1.9.1
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