[U-Boot] What is the correct way to configure SPL options?

[Charles Manning]

Hi All

My understanding of the way SPL is intended to be configured is:

(a) You have one config file for both SPL and u-boot.
(b) SPL features are selected via SPL-specific options.

I have a need to build SPL with MMC/FAT support, but I don't want
u-boot to have MMC/FAT support.

I do however see that quite a few SPL feature selections don't use SPL
config definitions though which would seem to violate (b) above.

eg.drivers/mmc/Makefile contains
COBJS-$(CONFIG_GENERIC_MMC) += mmc.o

It seems to me there are three ways to address this:

A) Change all those Makefiles to something like:

ifdef CONFIG_SPL_BUILD
COBJS-$(CONFIG_SPL_MMC_SUPPORT) += mmc.o
else
COBJS-$(CONFIG_GENERIC_MMC) += mmc.o
endif


B) Modifying the config file with something like

#ifdef CONFIG_SPL_BUILD
#define CONFIG_GENERIC_MMC
...
#endif

C) Separate config files. One for SPL and the other for u-boot.

Which is the best way to do this?

Thanks

Charles