u-boot-brain/config.mk
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

77 lines
2.0 KiB
Makefile

#
# (C) Copyright 2000-2013
# Wolfgang Denk, DENX Software Engineering, wd@denx.de.
#
# SPDX-License-Identifier: GPL-2.0+
#
#########################################################################
# clean the slate ...
PLATFORM_RELFLAGS =
PLATFORM_CPPFLAGS =
PLATFORM_LDFLAGS =
#########################################################################
# Load generated board configuration
ifeq ($(CONFIG_TPL_BUILD),y)
# Include TPL autoconf
sinclude include/tpl-autoconf.mk
else
ifeq ($(CONFIG_SPL_BUILD),y)
# Include SPL autoconf
sinclude include/spl-autoconf.mk
else
# Include normal autoconf
sinclude include/autoconf.mk
endif
endif
sinclude $(OBJTREE)/include/config.mk
# Some architecture config.mk files need to know what CPUDIR is set to,
# so calculate CPUDIR before including ARCH/SOC/CPU config.mk files.
# Check if arch/$ARCH/cpu/$CPU exists, otherwise assume arch/$ARCH/cpu contains
# CPU-specific code.
CPUDIR=arch/$(ARCH)/cpu/$(CPU)
ifneq ($(SRCTREE)/$(CPUDIR),$(wildcard $(SRCTREE)/$(CPUDIR)))
CPUDIR=arch/$(ARCH)/cpu
endif
sinclude $(TOPDIR)/arch/$(ARCH)/config.mk # include architecture dependend rules
sinclude $(TOPDIR)/$(CPUDIR)/config.mk # include CPU specific rules
ifdef SOC
sinclude $(TOPDIR)/$(CPUDIR)/$(SOC)/config.mk # include SoC specific rules
endif
ifdef VENDOR
BOARDDIR = $(VENDOR)/$(BOARD)
else
BOARDDIR = $(BOARD)
endif
ifdef BOARD
sinclude $(TOPDIR)/board/$(BOARDDIR)/config.mk # include board specific rules
endif
#########################################################################
RELFLAGS= $(PLATFORM_RELFLAGS)
OBJCFLAGS += --gap-fill=0xff
CPPFLAGS = $(KBUILD_CPPFLAGS) $(RELFLAGS)
CPPFLAGS += $(UBOOTINCLUDE)
CPPFLAGS += $(NOSTDINC_FLAGS) -pipe $(PLATFORM_CPPFLAGS)
CFLAGS := $(KBUILD_CFLAGS) $(CPPFLAGS)
BCURDIR = $(subst $(SRCTREE)/,,$(CURDIR:$(obj)%=%))
AFLAGS := $(KBUILD_AFLAGS) $(CPPFLAGS)
LDFLAGS += $(PLATFORM_LDFLAGS)
LDFLAGS_FINAL += -Bstatic
#########################################################################
export PLATFORM_CPPFLAGS PLATFORM_RELFLAGS CPPFLAGS CFLAGS AFLAGS