kbuild: consolidate Devicetree dtb build rules

There is nothing arch specific about building dtb files other than their
location under /arch/*/boot/dts/. Keeping each arch aligned is a pain.
The dependencies and supported targets are all slightly different.
Also, a cross-compiler for each arch is needed, but really the host
compiler preprocessor is perfectly fine for building dtbs. Move the
build rules to a common location and remove the arch specific ones. This
is done in a single step to avoid warnings about overriding rules.

The build dependencies had been a mixture of 'scripts' and/or 'prepare'.
These pull in several dependencies some of which need a target compiler
(specifically devicetable-offsets.h) and aren't needed to build dtbs.
All that is really needed is dtc, so adjust the dependencies to only be
dtc.

This change enables support 'dtbs_install' on some arches which were
missing the target.

Acked-by: Will Deacon <will.deacon@arm.com>
Acked-by: Paul Burton <paul.burton@mips.com>
Acked-by: Ley Foon Tan <ley.foon.tan@intel.com>
Acked-by: Masahiro Yamada <yamada.masahiro@socionext.com>
Cc: Michal Marek <michal.lkml@markovi.net>
Cc: Vineet Gupta <vgupta@synopsys.com>
Cc: Russell King <linux@armlinux.org.uk>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Yoshinori Sato <ysato@users.sourceforge.jp>
Cc: Michal Simek <monstr@monstr.eu>
Cc: Ralf Baechle <ralf@linux-mips.org>
Cc: James Hogan <jhogan@kernel.org>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Chris Zankel <chris@zankel.net>
Cc: Max Filippov <jcmvbkbc@gmail.com>
Cc: linux-kbuild@vger.kernel.org
Cc: linux-snps-arc@lists.infradead.org
Cc: linux-arm-kernel@lists.infradead.org
Cc: uclinux-h8-devel@lists.sourceforge.jp
Cc: linux-mips@linux-mips.org
Cc: nios2-dev@lists.rocketboards.org
Cc: linuxppc-dev@lists.ozlabs.org
Cc: linux-xtensa@linux-xtensa.org
Signed-off-by: Rob Herring <robh@kernel.org>

1 files changed, 1 insertions, 19 deletions

diff --git a/arch/arm/Makefile b/arch/arm/Makefile
index d1516f85f25d..161c2df6567e 100644
--- a/arch/arm/Makefile
+++ b/arch/arm/Makefile
@@ -307,12 +307,7 @@ else
 KBUILD_IMAGE := $(boot)/zImage
 endif
 
-# Build the DT binary blobs if we have OF configured
-ifeq ($(CONFIG_USE_OF),y)
-KBUILD_DTBS := dtbs
-endif
-
-all:	$(notdir $(KBUILD_IMAGE)) $(KBUILD_DTBS)
+all:	$(notdir $(KBUILD_IMAGE))
 
 
 archheaders:
@@ -339,17 +334,6 @@ $(BOOT_TARGETS): vmlinux
 $(INSTALL_TARGETS):
 	$(Q)$(MAKE) $(build)=$(boot) MACHINE=$(MACHINE) $@
 
-%.dtb: | scripts
-	$(Q)$(MAKE) $(build)=$(boot)/dts MACHINE=$(MACHINE) $(boot)/dts/$@
-
-PHONY += dtbs dtbs_install
-
-dtbs: prepare scripts
-	$(Q)$(MAKE) $(build)=$(boot)/dts
-
-dtbs_install:
-	$(Q)$(MAKE) $(dtbinst)=$(boot)/dts
-
 PHONY += vdso_install
 vdso_install:
 ifeq ($(CONFIG_VDSO),y)
@@ -371,8 +355,6 @@ define archhelp
   echo  '  uImage        - U-Boot wrapped zImage'
   echo  '  bootpImage    - Combined zImage and initial RAM disk'
   echo  '                  (supply initrd image via make variable INITRD=<path>)'
-  echo  '* dtbs          - Build device tree blobs for enabled boards'
-  echo  '  dtbs_install  - Install dtbs to $(INSTALL_DTBS_PATH)'
   echo  '  install       - Install uncompressed kernel'
   echo  '  zinstall      - Install compressed kernel'
   echo  '  uinstall      - Install U-Boot wrapped compressed kernel'