MIPS: add initial infrastructure for device-tree files

Prepare sub-folder for device-tree files. Make support for
device-tree on MIPS available in Kbuild/Kconfig.

Signed-off-by: Daniel Schwierzeck <daniel.schwierzeck@gmail.com>
Signed-off-by: Purna Chandra Mandal <purna.mandal@microchip.com>

arch/Kconfig

@@ -55,6 +55,7 @@ config MIPS
 	select HAVE_PRIVATE_LIBGCC
 	select HAVE_GENERIC_BOARD
 	select SYS_GENERIC_BOARD
+	select SUPPORT_OF_CONTROL
 
 config NDS32
 	bool "NDS32 architecture"

arch/mips/config.mk

@@ -72,6 +72,7 @@ PF_ABICALLS			:= -mabicalls
 PF_PIC				:= -fpic
 PF_PIE				:= -pie
 PF_OBJCOPY			:= -j .got -j .u_boot_list -j .rel.dyn -j .padding
+PF_OBJCOPY			+= -j .dtb.init.rodata
 endif
 
 PLATFORM_CPPFLAGS		+= -G 0 $(PF_ABICALLS) $(PF_PIC)

arch/mips/dts/.gitignore

@@ -0,0 +1 @@
+*.dtb

arch/mips/dts/Makefile

@@ -0,0 +1,16 @@
+#
+# SPDX-License-Identifier:	GPL-2.0+
+#
+
+dtb-y +=
+
+targets += $(dtb-y)
+
+# Add any required device tree compiler flags here
+DTC_FLAGS +=
+
+PHONY += dtbs
+dtbs: $(addprefix $(obj)/, $(dtb-y))
+	@:
+
+clean-files := *.dtb

arch/mips/dts/include/dt-bindings

@@ -0,0 +1 @@
+../../../../include/dt-bindings

arch/mips/dts/skeleton.dtsi

@@ -0,0 +1,23 @@
+/*
+ * Skeleton device tree; the bare minimum needed to boot; just include and
+ * add a compatible value.  The bootloader will typically populate the memory
+ * node.
+ *
+ * SPDX-License-Identifier:	GPL-2.0+
+ */
+
+/ {
+	#address-cells = <1>;
+	#size-cells = <1>;
+
+	chosen {
+	};
+
+	aliases {
+	};
+
+	memory {
+		device_type = "memory";
+		reg = <0 0>;
+	};
+};

dts/Makefile

@@ -45,4 +45,4 @@ dtbs: $(obj)/dt.dtb
 clean-files := dt.dtb.S
 
 # Let clean descend into dts directories
-subdir- += ../arch/arm/dts ../arch/microblaze/dts ../arch/sandbox/dts ../arch/x86/dts
+subdir- += ../arch/arm/dts ../arch/microblaze/dts ../arch/mips/dts ../arch/sandbox/dts ../arch/x86/dts