From 9e4140329ee9a787d0f96ac2829d618d47f7973f Mon Sep 17 00:00:00 2001
From: Masahiro Yamada <yamada.m@jp.panasonic.com>
Date: Tue, 4 Feb 2014 17:24:24 +0900
Subject: 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>
---
 config.mk | 42 +++---------------------------------------
 1 file changed, 3 insertions(+), 39 deletions(-)

(limited to 'config.mk')

diff --git a/config.mk b/config.mk
index ed1a51972f..0fa316743c 100644
--- a/config.mk
+++ b/config.mk
@@ -6,42 +6,6 @@
 #
 #########################################################################
 
-ifeq ($(CURDIR),$(SRCTREE))
-dir :=
-else
-dir := $(subst $(SRCTREE)/,,$(CURDIR))
-endif
-
-ifneq ($(OBJTREE),$(SRCTREE))
-# Create object files for SPL in a separate directory
-ifeq ($(CONFIG_SPL_BUILD),y)
-ifeq ($(CONFIG_TPL_BUILD),y)
-obj := $(if $(dir),$(TPLTREE)/$(dir)/,$(TPLTREE)/)
-else
-obj := $(if $(dir),$(SPLTREE)/$(dir)/,$(SPLTREE)/)
-endif
-else
-obj := $(if $(dir),$(OBJTREE)/$(dir)/,$(OBJTREE)/)
-endif
-src := $(if $(dir),$(SRCTREE)/$(dir)/,$(SRCTREE)/)
-
-$(shell mkdir -p $(obj))
-else
-# Create object files for SPL in a separate directory
-ifeq ($(CONFIG_SPL_BUILD),y)
-ifeq ($(CONFIG_TPL_BUILD),y)
-obj := $(if $(dir),$(TPLTREE)/$(dir)/,$(TPLTREE)/)
-else
-obj := $(if $(dir),$(SPLTREE)/$(dir)/,$(SPLTREE)/)
-
-endif
-$(shell mkdir -p $(obj))
-else
-obj :=
-endif
-src :=
-endif
-
 # clean the slate ...
 PLATFORM_RELFLAGS =
 PLATFORM_CPPFLAGS =
@@ -52,14 +16,14 @@ PLATFORM_LDFLAGS =
 # Load generated board configuration
 ifeq ($(CONFIG_TPL_BUILD),y)
 # Include TPL autoconf
-sinclude $(OBJTREE)/include/tpl-autoconf.mk
+sinclude include/tpl-autoconf.mk
 else
 ifeq ($(CONFIG_SPL_BUILD),y)
 # Include SPL autoconf
-sinclude $(OBJTREE)/include/spl-autoconf.mk
+sinclude include/spl-autoconf.mk
 else
 # Include normal autoconf
-sinclude $(OBJTREE)/include/autoconf.mk
+sinclude include/autoconf.mk
 endif
 endif
 sinclude $(OBJTREE)/include/config.mk
-- 
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