[U-Boot] Problem: the build does not recurse into subdirectory

[Maxim Sloyko]

Greetings,

I'm working on adding new platform to U-Boot and right now I'm trying
to clean up the directory structure, but running into a problem of
Make not recursing into a subdirectory that I've created.

in my arch/arm/mach-aspeed/Makefile I have this:

obj-$(CONFIG_ASPEED_AST2500) += ast2500/ ast2500-board.o

and then in arch/arm/mach-aspeed/ast2500/Makefile:

$obj-y += clk_ast2500.o sdram_ast2500.o

When I try to build everything, I get this error:

arm-linux-gnueabi-ld.bfd: cannot find
arch/arm/mach-aspeed/ast2500/built-in.o: No such file or directory

If instead in arch/arm/mach-aspeed/Makefile I specify:

obj-$(CONFIG_ASPEED_AST2500) += ast2500/clk_ast2500.o
ast2500/sdram_ast2500.o ast2500-board.o

(That is, I just added binaries from the lower level dir explicitly)

everything builds fine, which means that CONFIG_ASPEED_AST2500 is defined.

Any ideas what might be the problem here?

If you need more details, you can see the code here
https://github.com/maksymko/u-boot/tree/aspeed_ast2500_evb/arch/arm/mach-aspeed

Many thanks for the help!

-- 
Maxim Sloyko