kbuild: change out-of-tree build
This commit changes the working directory
where the build process occurs.
Before this commit, build process occurred under the source
tree for both in-tree and out-of-tree build.
That's why we needed to add $(obj) prefix to all generated
files in makefiles like follows:
$(obj)u-boot.bin: $(obj)u-boot
Here, $(obj) is empty for in-tree build, whereas it points
to the output directory for out-of-tree build.
And our old build system changes the current working directory
with "make -C <sub-dir>" syntax when descending into the
sub-directories.
On the other hand, Kbuild uses a different idea
to handle out-of-tree build and directory descending.
The build process of Kbuild always occurs under the output tree.
When "O=dir/to/store/output/files" is given, the build system
changes the current working directory to that directory and
restarts the make.
Kbuild uses "make -f $(srctree)/scripts/Makefile.build obj=<sub-dir>"
syntax for descending into sub-directories.
(We can write it like "make $(obj)=<sub-dir>" with a shorthand.)
This means the current working directory is always the top
of the output directory.
Signed-off-by: Masahiro Yamada <yamada.m@jp.panasonic.com>
Tested-by: Gerhard Sittig <gsi@denx.de>
diff --git a/arch/blackfin/cpu/Makefile b/arch/blackfin/cpu/Makefile
index a61594a..369dc74 100644
--- a/arch/blackfin/cpu/Makefile
+++ b/arch/blackfin/cpu/Makefile
@@ -25,9 +25,9 @@
# make sure our initcode (which goes into LDR) does not
# have relocs or external references
-$(obj)initcode.o: CFLAGS += -fno-function-sections -fno-data-sections
+$(obj)/initcode.o: CFLAGS += -fno-function-sections -fno-data-sections
READINIT = env LC_ALL=C $(CROSS_COMPILE)readelf -s $<
-$(obj)check_initcode: $(obj)initcode.o
+$(obj)/check_initcode: $(obj)/initcode.o
ifneq ($(CONFIG_BFIN_BOOT_MODE),BFIN_BOOT_BYPASS)
@if $(READINIT) | grep '\<GLOBAL\>.*\<UND\>' ; then \
echo "$< contains external references!" 1>&2 ; \
@@ -35,7 +35,7 @@
fi
endif
-$(obj)init.lds: init.lds.S
+$(obj)/init.lds: $(src)/init.lds.S
$(CPP) $(CPPFLAGS) $(LDPPFLAGS) -ansi -D__ASSEMBLY__ -P $^ -o $@
-$(obj)init.elf: $(obj)init.lds $(obj)init.o $(obj)initcode.o
+$(obj)/init.elf: $(obj)/init.lds $(obj)/init.o $(obj)/initcode.o
$(LD) $(LDFLAGS) -T $^ -o $@