I wanted to call a C function defined in arm-tf (arm trusted firmware) from a u-boot assembly code. That assembly code of u-boot is arch/arm/lib/gic_64.S. The build process for this doesn't work out as I wanted so I ask it here with simple example.
In u-boot build tree, there is the directory arch/arm/lib. I added a directory arch/arm/lib/testd and put testf.c there. testf.c is just printing a string. In arch/arm/lib/Makefile, I added
libs-y += arch/arm/lib/testd
and in arch/arm/lib/testd/Makefile, I added
obj-y += testf.o
When I do make in u-boot root directory, I find nothing is made under arch/arm/lib/testd. But if I do make arch/arm/lib/testd/testf.o, that file is made. I saw this question but it doesn't help. Actually I guess I should see spl/arch/arm/lib/testd/{built-in.o, testf.o} if it was successful(because I'm building u-boot-spl).
I will be very grateful if anyone could tell me how I should do it. Thanks!
It looks like, if I add in arch/arm/lib/Makefile only
obj-y += testd/
Then by doing make I see arch/arm/lib/testd/testf.o and spl/arch/arm/lib/testd/{build-in.o,testf.o} generated.
The key part was the testd/ not testd.