kbuild: use Linux Kernel build scripts

Now we are ready to switch over to real Kbuild.

This commit disables temporary scripts:
  scripts/{Makefile.build.tmp, Makefile.host.tmp}
and enables real Kbuild scripts:
  scripts/{Makefile.build,Makefile.host,Makefile.lib}.

This switch is triggered by the line in scripts/Kbuild.include
  -build := -f $(if $(KBUILD_SRC),$(srctree)/)scripts/Makefile.build.tmp obj
  +build := -f $(if $(KBUILD_SRC),$(srctree)/)scripts/Makefile.build obj

We need to adjust some build scripts for U-Boot.
But smaller amount of modification is preferable.

Additionally, we need to fix compiler flags which are
locally added or removed.

In Kbuild, it is not allowed to change CFLAGS locally.
Instead, ccflags-y, asflags-y, cppflags-y,
CFLAGS_$(basetarget).o, CFLAGS_REMOVE_$(basetarget).o
are prepared for that purpose.

Signed-off-by: Masahiro Yamada <yamada.m@jp.panasonic.com>
Tested-by: Gerhard Sittig <gsi@denx.de>

1 files changed, 19 insertions, 3 deletions

diff --git a/scripts/Makefile.build b/scripts/Makefile.build
index d5d859c807..2a87984a31 100644
--- a/scripts/Makefile.build
+++ b/scripts/Makefile.build
@@ -2,7 +2,16 @@
 # Building
 # ==========================================================================
 
-src := $(obj)
+# Modified for U-Boot
+ifeq ($(CONFIG_TPL_BUILD),y)
+  src := $(patsubst tpl/%,%,$(obj))
+else
+  ifeq ($(CONFIG_SPL_BUILD),y)
+    src := $(patsubst spl/%,%,$(obj))
+  else
+    src := $(obj)
+  endif
+endif
 
 PHONY := __build
 __build:
@@ -35,6 +44,11 @@ subdir-ccflags-y :=
 
 include scripts/Kbuild.include
 
+# Added for U-Boot
+# We must include config.mk after Kbuild.include
+# so that some config.mk can use cc-option.
+include config.mk
+
 # For backward compatibility check that these variables do not change
 save-cflags := $(CFLAGS)
 
@@ -115,14 +129,16 @@ ifneq ($(hostprogs-y)$(hostprogs-m),)
 include scripts/Makefile.host
 endif
 
-ifneq ($(KBUILD_SRC),)
+# Uncommented for U-Boot
+#  We need to create output dicrectory for SPL and TPL even for in-tree build
+#ifneq ($(KBUILD_SRC),)
 # Create output directory if not already present
 _dummy := $(shell [ -d $(obj) ] || mkdir -p $(obj))
 
 # Create directories for object files if directory does not exist
 # Needed when obj-y := dir/file.o syntax is used
 _dummy := $(foreach d,$(obj-dirs), $(shell [ -d $(d) ] || mkdir -p $(d)))
-endif
+#endif
 
 ifndef obj
 $(warning kbuild: Makefile.build is included improperly)