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, 14 deletions

diff --git a/arch/mips/Makefile b/arch/mips/Makefile
index d74b3742fa5d..d43eeaa6d75b 100644
--- a/arch/mips/Makefile
+++ b/arch/mips/Makefile
@@ -407,18 +407,7 @@ endif
 CLEAN_FILES += vmlinux.32 vmlinux.64
 
 # device-trees
-core-$(CONFIG_BUILTIN_DTB) += arch/mips/boot/dts/
-
-%.dtb %.dtb.S %.dtb.o: | scripts
-	$(Q)$(MAKE) $(build)=arch/mips/boot/dts arch/mips/boot/dts/$@
-
-PHONY += dtbs
-dtbs: scripts
-	$(Q)$(MAKE) $(build)=arch/mips/boot/dts
-
-PHONY += dtbs_install
-dtbs_install:
-	$(Q)$(MAKE) $(dtbinst)=arch/mips/boot/dts
+core-y += arch/mips/boot/dts/
 
 archprepare:
 ifdef CONFIG_MIPS32_N32
@@ -461,8 +450,6 @@ define archhelp
 	echo '  uImage.lzma          - U-Boot image (lzma)'
 	echo '  uImage.lzo           - U-Boot image (lzo)'
 	echo '  uzImage.bin          - U-Boot image (self-extracting)'
-	echo '  dtbs                 - Device-tree blobs for enabled boards'
-	echo '  dtbs_install         - Install dtbs to $(INSTALL_DTBS_PATH)'
 	echo
 	echo '  These will be default as appropriate for a configured platform.'
 	echo