[POWERPC] add target for building .dtb files

Call dtc from the Makefile instead of the wrapper script so that the dt
blobs can be generated with a simple make invocation.

Using this patch allows board ports to trigger automatic building of .dtb
files by adding them to the image-y target list.

Signed-off-by: Grant Likely <[e-mail]>
Signed-off-by: Josh Boyer <[e-mail]>

arch/powerpc/Makefile

···
 $(BOOT_TARGETS): vmlinux
 	$(Q)$(MAKE) ARCH=ppc64 $(build)=$(boot) $(patsubst %,$(boot)/%,$@)
 
-bootwrapper_install:
+bootwrapper_install %.dtb:
 	$(Q)$(MAKE) ARCH=ppc64 $(build)=$(boot) $(patsubst %,$(boot)/%,$@)
 
 define archhelp

arch/powerpc/boot/Makefile

···
 	$(call if_changed,wrap,$*)
 
 # dtbImage% - a dtbImage is a zImage with an embedded device tree blob
-$(obj)/dtbImage.initrd.%: vmlinux $(wrapperbits) $(dtstree)/%.dts
-	$(call if_changed,wrap,$*,$(dtstree)/$*.dts,,$(obj)/ramdisk.image.gz)
+$(obj)/dtbImage.initrd.%: vmlinux $(wrapperbits) $(obj)/%.dtb
+	$(call if_changed,wrap,$*,,$(obj)/$*.dtb,$(obj)/ramdisk.image.gz)
 
-$(obj)/dtbImage.%: vmlinux $(wrapperbits) $(dtstree)/%.dts
-	$(call if_changed,wrap,$*,$(dtstree)/$*.dts)
+$(obj)/dtbImage.%: vmlinux $(wrapperbits) $(obj)/%.dtb
+	$(call if_changed,wrap,$*,,$(obj)/$*.dtb)
 
 # This cannot be in the root of $(src) as the zImage rule always adds a $(obj)
 # prefix
···
 $(obj)/uImage: vmlinux $(wrapperbits)
 	$(call if_changed,wrap,uboot)
 
-$(obj)/cuImage.%: vmlinux $(dtstree)/%.dts $(wrapperbits)
-	$(call if_changed,wrap,cuboot-$*,$(dtstree)/$*.dts)
+$(obj)/cuImage.%: vmlinux $(obj)/%.dtb $(wrapperbits)
+	$(call if_changed,wrap,cuboot-$*,,$(obj)/$*.dtb)
 
-$(obj)/treeImage.initrd.%: vmlinux $(dtstree)/%.dts $(wrapperbits)
-	$(call if_changed,wrap,treeboot-$*,$(dtstree)/$*.dts,,$(obj)/ramdisk.image.gz)
+$(obj)/treeImage.initrd.%: vmlinux $(obj)/%.dtb $(wrapperbits)
+	$(call if_changed,wrap,treeboot-$*,,$(obj)/$*.dtb,$(obj)/ramdisk.image.gz)
 
-$(obj)/treeImage.%: vmlinux $(dtstree)/%.dts $(wrapperbits)
-	$(call if_changed,wrap,treeboot-$*,$(dtstree)/$*.dts)
+$(obj)/treeImage.%: vmlinux $(obj)/%.dtb $(wrapperbits)
+	$(call if_changed,wrap,treeboot-$*,,$(obj)/$*.dtb)
+
+# Rule to build device tree blobs
+$(obj)/%.dtb: $(dtstree)/%.dts $(obj)/dtc
+	$(obj)/dtc -O dtb -o $(obj)/$*.dtb -b 0 $(DTS_FLAGS) $(dtstree)/$*.dts
 
 # If there isn't a platform selected then just strip the vmlinux.
 ifeq (,$(image-y))
···
 
 # anything not in $(targets)
 clean-files += $(image-) $(initrd-) zImage zImage.initrd cuImage.* treeImage.* \
-	otheros.bld
+	otheros.bld *.dtb
 
 # clean up files cached by wrapper
 clean-kernel := vmlinux.strip vmlinux.bin