From e7b5dd0e1dd5eacd13bee7bc5da2eeea8882e668 Mon Sep 17 00:00:00 2001
From: Jonas Gorski <jogo@openwrt.org>
Date: Thu, 16 Jul 2015 11:12:52 +0000
Subject: [PATCH] image.mk: add a BuildDTB define

Add a Image/BuildDTB command that takes the path to an dts file and
applies the CPP using the default include directories, then uses dtc
to compile the dts as the specified output file.
Additional CPP and DTC flags can be supplied as additional arguments.

Signed-off-by: Jonas Gorski <jogo@openwrt.org>

SVN-Revision: 46389
---
 include/image.mk | 16 ++++++++++++++++
 1 file changed, 16 insertions(+)

diff --git a/include/image.mk b/include/image.mk
index 6767e76dc1..a20e090fe7 100644
--- a/include/image.mk
+++ b/include/image.mk
@@ -126,6 +126,22 @@ define Image/BuildKernel/MkFIT
 	PATH=$(LINUX_DIR)/scripts/dtc:$(PATH) mkimage -f $(KDIR)/fit-$(1).its $(KDIR)/fit-$(1)$(7).itb
 endef
 
+# $(1) source dts file
+# $(2) target dtb file
+# $(3) extra CPP flags
+# $(4) extra DTC flags
+define Image/BuildDTB
+	$(CPP) -nostdinc -x assembler-with-cpp \
+		-I$(LINUX_DIR)/arch/$(ARCH)/boot/dts \
+		-I$(LINUX_DIR)/arch/$(ARCH)/boot/dts/include \
+		-undef -D__DTS__ $(3) \
+		-o $(2).tmp $(1)
+	$(LINUX_DIR)/scripts/dtc/dtc -O dtb \
+		-i$(dir $(1)) $(4) \
+		-o $(2) $(2).tmp
+	$(RM) $(2).tmp
+endef
+
 define Image/mkfs/jffs2/sub
 		$(STAGING_DIR_HOST)/bin/mkfs.jffs2 $(3) --pad -e $(patsubst %k,%KiB,$(1)) -o $(KDIR)/root.jffs2-$(2) -d $(TARGET_DIR) -v 2>&1 1>/dev/null | awk '/^.+$$$$/'
 		$(call add_jffs2_mark,$(KDIR)/root.jffs2-$(2))