HI Masahiro,
In my fiddling with Rockchip in SPL I found that the current single config is simple, but a little too limited. You discussed this briefly with someone from Marvell also. At present we effectively have two options:
1. decide for all boards that a uclass should be supported in SPL (and put it in Makefile.spl, or not)
2. ugly #undefs to try to fix things up after the fact (i.e. #ifdef CONFIG_SPL_BUILD...#undef CONFIG_PINCTRL)
You mentioned the idea of allowing something like this:
spl-$(CONFIG_FRED) += file.o
In practice I assume you would generate two config headers from the same input: one for SPL and one for U-Boot proper.
Another option would be to allow several states for the same config. At present in the .config files we have:
CONFIG_FRED=y
We could allow:
CONFIG_FRED=yyn
meaning yes for U-Boot proper, yes for SPL, no for TPL (assuming these are enabled for the board). For this we would need a new type, similar to tristate which allows cycling through the options.
In the Makefile we could have
obj-$(CONFIG_FRED) += file.o
and then Kbuild would do the right thing - i.e. include the file for U-Boot proper, SPL but not TPL.
What do you think about this? I fear that we need to figure something out...
Regards, Simon