u-boot-brain/examples/api/Makefile
Masahiro Yamada 9e4140329e 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>
2014-02-19 11:07:50 -05:00

63 lines
1.9 KiB
Makefile

#
# (C) Copyright 2007 Semihalf
#
# SPDX-License-Identifier: GPL-2.0+
#
ifdef FTRACE
CFLAGS += -finstrument-functions -DFTRACE
endif
ifeq ($(ARCH),powerpc)
LOAD_ADDR = 0x40000
endif
ifeq ($(ARCH),arm)
LOAD_ADDR = 0x1000000
endif
# Resulting ELF and binary exectuables will be named demo and demo.bin
extra-y = demo
# Source files located in the examples/api directory
SOBJ_FILES-y += crt0.o
COBJ_FILES-y += demo.o
COBJ_FILES-y += glue.o
COBJ_FILES-y += libgenwrap.o
# Source files which exist outside the examples/api directory
EXT_COBJ_FILES-y += lib/crc32.o
EXT_COBJ_FILES-y += lib/ctype.o
EXT_COBJ_FILES-y += lib/div64.o
EXT_COBJ_FILES-y += lib/string.o
EXT_COBJ_FILES-y += lib/time.o
EXT_COBJ_FILES-y += lib/vsprintf.o
EXT_SOBJ_FILES-$(CONFIG_PPC) += arch/powerpc/lib/ppcstring.o
# Create a list of source files so their dependencies can be auto-generated
SRCS += $(addprefix $(SRCTREE)/,$(EXT_COBJ_FILES-y:.o=.c))
SRCS += $(addprefix $(SRCTREE)/,$(EXT_SOBJ_FILES-y:.o=.S))
SRCS += $(addprefix $(SRCTREE)/examples/api/,$(COBJ_FILES-y:.o=.c))
SRCS += $(addprefix $(SRCTREE)/examples/api/,$(SOBJ_FILES-y:.o=.S))
# Create a list of object files to be compiled
OBJS += $(addprefix $(obj)/,$(SOBJ_FILES-y))
OBJS += $(addprefix $(obj)/,$(COBJ_FILES-y))
OBJS += $(addprefix $(obj)/,$(notdir $(EXT_COBJ_FILES-y)))
OBJS += $(addprefix $(obj)/,$(notdir $(EXT_SOBJ_FILES-y)))
#########################################################################
$(obj)/demo: $(OBJS)
$(LD) --gc-sections -Ttext $(LOAD_ADDR) -o $@ $^ $(PLATFORM_LIBS)
$(obj)/demo.bin: $(obj)/demo
$(OBJCOPY) -O binary $< $@ 2>/dev/null
# Rule to build generic library C files
$(addprefix $(obj)/,$(notdir $(EXT_COBJ_FILES-y))): $(obj)/%.o: $(SRCTREE)/lib/%.c
$(CC) -g $(CFLAGS) -c -o $@ $<
# Rule to build architecture-specific library assembly files
$(addprefix $(obj)/,$(notdir $(EXT_SOBJ_FILES-y))): $(obj)/%.o: $(SRCTREE)/arch/$(ARCH)/lib/%.S
$(CC) -g $(CFLAGS) -c -o $@ $<