devicetree: Move include prefixes from arch to separate directory

We use a directory under arch/$ARCH/boot/dts as an include path
that has links outside of the subtree to find dt-bindings from under
include/dt-bindings. That's been working well, but new DT architectures
haven't been adding them by default.

Recently there's been a desire to share some of the DT material between
arm and arm64, which originally caused developers to create symlinks or
relative includes between the subtrees. This isn't ideal -- it breaks
if the DT files aren't stored in the exact same hierarchy as the kernel
tree, and generally it's just icky.

As a somewhat cleaner solution we decided to add a $ARCH/ prefix link
once, and allow DTS files to reference dtsi (and dts) files in other
architectures that way.

Original approach was to create these links under each architecture,
but it lead to the problem of recursive symlinks.

As a remedy, move the include link directories out of the architecture
trees into a common location. At the same time, they can now share one
directory and one dt-bindings/ link as well.

Fixes: 4027494 ('ARM: dts: add arm/arm64 include symlinks')
Reported-by: Russell King <[email protected]>
Reported-by: Omar Sandoval <[email protected]>
Reviewed-by: Heiko Stuebner <[email protected]>
Reviewed-by: Masahiro Yamada <[email protected]>
Tested-by: Heiko Stuebner <[email protected]>
Acked-by: Rob Herring <[email protected]>
Cc: Heiko Stuebner <[email protected]>
Cc: Mark Rutland <[email protected]>
Cc: Russell King <[email protected]>
Cc: Catalin Marinas <[email protected]>
Cc: Will Deacon <[email protected]>
Cc: Mikael Starvik <[email protected]>
Cc: Jesper Nilsson <[email protected]>
Cc: James Hogan <[email protected]>
Cc: Ralf Baechle <[email protected]>
Cc: Benjamin Herrenschmidt <[email protected]>
Cc: Paul Mackerras <[email protected]>
Cc: Michael Ellerman <[email protected]>
Cc: Frank Rowand <[email protected]>
Cc: linux-arch <[email protected]>
Signed-off-by: Olof Johansson <[email protected]>

scripts/Makefile.lib

@@ -175,7 +175,7 @@ ld_flags       = $(LDFLAGS) $(ldflags-y)
 
 dtc_cpp_flags  = -Wp,-MD,$(depfile).pre.tmp -nostdinc                    \
 		 -I$(srctree)/arch/$(SRCARCH)/boot/dts                   \
-		 -I$(srctree)/arch/$(SRCARCH)/boot/dts/include           \
+		 -I$(srctree)/scripts/dtc/include-prefixes               \
 		 -I$(srctree)/drivers/of/testcase-data                   \
 		 -undef -D__DTS__
 

scripts/dtc/include-prefixes/arc

@@ -0,0 +1 @@
+../../../arch/arc/boot/dts

scripts/dtc/include-prefixes/arm

@@ -0,0 +1 @@
+../../../arch/arm/boot/dts

scripts/dtc/include-prefixes/arm64

@@ -0,0 +1 @@
+../../../arch/arm64/boot/dts

scripts/dtc/include-prefixes/c6x

@@ -0,0 +1 @@
+../../../arch/c6x/boot/dts

scripts/dtc/include-prefixes/cris

@@ -0,0 +1 @@
+../../../arch/cris/boot/dts

scripts/dtc/include-prefixes/dt-bindings

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

scripts/dtc/include-prefixes/h8300

@@ -0,0 +1 @@
+../../../arch/h8300/boot/dts

scripts/dtc/include-prefixes/metag

@@ -0,0 +1 @@
+../../../arch/metag/boot/dts

scripts/dtc/include-prefixes/microblaze

@@ -0,0 +1 @@
+../../../arch/microblaze/boot/dts

scripts/dtc/include-prefixes/mips

@@ -0,0 +1 @@
+../../../arch/mips/boot/dts

scripts/dtc/include-prefixes/nios2

@@ -0,0 +1 @@
+../../../arch/nios2/boot/dts

scripts/dtc/include-prefixes/openrisc

@@ -0,0 +1 @@
+../../../arch/openrisc/boot/dts

scripts/dtc/include-prefixes/powerpc

@@ -0,0 +1 @@
+../../../arch/powerpc/boot/dts

scripts/dtc/include-prefixes/sh

@@ -0,0 +1 @@
+../../../arch/sh/boot/dts

scripts/dtc/include-prefixes/xtensa

@@ -0,0 +1 @@
+../../../arch/xtensa/boot/dts