[PATCH V6] kbuild: dtbs_install: new make target

[Jason Cooper]

Unlike other build products in the Linux kernel, there is no 'make
*install' mechanism to put devicetree blobs in a standard place.

This patch is an attempt to fix this problem.  Akin to 'make install',
this creates a new make target, dtbs_install.  The script that gets
called defers to a distribution or user supplied installdtbs binary,
if found in the system.  Otherwise, the default action is to install the
built dtbs into

  /lib/devicetrees/${kernel_version}/${dts_filename}.dtb

This is done to keep dtbs from different kernel versions separate until
things have settled down.  Once the dtbs are stable, and not so strongly
linked to the kernel version, the devicetree files will most likely move
to their own repo.  Users will need to upgrade install scripts at that
time.

/lib has been selected over /boot since /boot is often a FAT filesystem
and a majority of the dts filenames are longer than 8+3.

Signed-off-by: Jason Cooper <jason at lakedaemon.net>
---
Note: Stephen, I haven't added your Ack because I wanted to make sure you were
Ok with the change to /lib in light of /boot partitions formatted to FAT

changes since v5:
 - move make target back to arch/arm/Makefile (gcl)
 - change default install location to /lib from /boot (FAT) (ojn,jac)

changes since v4:
 - move make target from arch/arm/Makefile to Makefile (swarren)
 - change default install location to /boot/devicetrees/$KERNVER (swarren/gcl)
 - add INSTALL_DTBS_PATH for changing build root (jac)

changes since v3:
 - drop renaming files to ${compat}.dtb (rmk/swarren)
 - move installdtbs.sh to ./scripts/ (gcl)

changes since v2:
 - use fdtget instead of a modified dtc to get the board compat string

changes since v1:
 - added this patch

 Makefile               | 12 +++++++++++-
 arch/arm/Makefile      | 10 ++++++++++
 scripts/installdtbs.sh | 33 +++++++++++++++++++++++++++++++++
 3 files changed, 54 insertions(+), 1 deletion(-)
 create mode 100644 scripts/installdtbs.sh

diff --git a/Makefile b/Makefile
index c0c2d58e3998..240e0d52b126 100644
--- a/Makefile
+++ b/Makefile
@@ -339,6 +339,7 @@ OBJDUMP		= $(CROSS_COMPILE)objdump
 AWK		= awk
 GENKSYMS	= scripts/genksyms/genksyms
 INSTALLKERNEL  := installkernel
+INSTALLDTBS    := installdtbs
 DEPMOD		= /sbin/depmod
 PERL		= perl
 CHECK		= sparse
@@ -391,7 +392,7 @@ KERNELVERSION = $(VERSION)$(if $(PATCHLEVEL),.$(PATCHLEVEL)$(if $(SUBLEVEL),.$(S
 export VERSION PATCHLEVEL SUBLEVEL KERNELRELEASE KERNELVERSION
 export ARCH SRCARCH CONFIG_SHELL HOSTCC HOSTCFLAGS CROSS_COMPILE AS LD CC
 export CPP AR NM STRIP OBJCOPY OBJDUMP
-export MAKE AWK GENKSYMS INSTALLKERNEL PERL UTS_MACHINE
+export MAKE AWK GENKSYMS INSTALLKERNEL INSTALLDTBS PERL UTS_MACHINE
 export HOSTCXX HOSTCXXFLAGS LDFLAGS_MODULE CHECK CHECKFLAGS
 
 export KBUILD_CPPFLAGS NOSTDINC_FLAGS LINUXINCLUDE OBJCOPYFLAGS LDFLAGS
@@ -704,6 +705,15 @@ export KBUILD_IMAGE ?= vmlinux
 export	INSTALL_PATH ?= /boot
 
 #
+# INSTALL_DTBS_PATH specifies a prefix for relocations required by build roots.
+# Like INSTALL_MOD_PATH, it isn't defined in the Makefile, but can be passed as
+# an argument if needed.
+#
+
+DTBBOOT = $(INSTALL_DTBS_PATH)/lib/devicetrees/$(KERNELRELEASE)
+export DTBBOOT
+
+#
 # INSTALL_MOD_PATH specifies a prefix to MODLIB for module directory
 # relocations required by build roots.  This is not defined in the
 # makefile but the argument can be passed to make if needed.
diff --git a/arch/arm/Makefile b/arch/arm/Makefile
index c99b1086d83d..400a3a7ee899 100644
--- a/arch/arm/Makefile
+++ b/arch/arm/Makefile
@@ -314,6 +314,12 @@ PHONY += dtbs
 dtbs: scripts
 	$(Q)$(MAKE) $(build)=$(boot)/dts MACHINE=$(MACHINE) dtbs
 
+PHONY += dtbs_install
+
+dtbs_install: dtbs
+	$(CONFIG_SHELL) $(srctree)/scripts/installdtbs.sh $(KERNELRELEASE) \
+	"$(DTBBOOT)" "$(srctree)"
+
 # We use MRPROPER_FILES and CLEAN_FILES now
 archclean:
 	$(Q)$(MAKE) $(clean)=$(boot)
@@ -331,6 +337,10 @@ define archhelp
   echo  '  bootpImage    - Combined zImage and initial RAM disk'
   echo  '                  (supply initrd image via make variable INITRD=<path>)'
   echo  '* dtbs          - Build device tree blobs for enabled boards'
+  echo  '  dtbs_install  - Install dtbs'
+  echo  '                  Install using (your) ~/bin/$(INSTALLDTBS) or'
+  echo  '                  (distribution) /sbin/$(INSTALLDTBS) or'
+  echo  '                  install to $(DTBBOOT)'
   echo  '  install       - Install uncompressed kernel'
   echo  '  zinstall      - Install compressed kernel'
   echo  '  uinstall      - Install U-Boot wrapped compressed kernel'
diff --git a/scripts/installdtbs.sh b/scripts/installdtbs.sh
new file mode 100644
index 000000000000..11027f00c3a4
--- /dev/null
+++ b/scripts/installdtbs.sh
@@ -0,0 +1,33 @@
+#!/bin/sh
+#
+# This file is subject to the terms and conditions of the GNU General Public
+# License.  See the file "COPYING" in the main directory of this archive
+# for more details.
+#
+# Copyright (C) 1995 by Linus Torvalds
+#
+# Adapted from code in arch/i386/boot/Makefile by H. Peter Anvin
+#
+# Further adapted from arch/x86/boot/install.sh by Jason Cooper
+#
+# "make dtbs_install" script
+#
+# Arguments:
+#   $1 - kernel version
+#   $2 - default install path (blank if root directory)
+#   $3 - directory containing dtbs
+#
+
+# User may have a custom install script
+
+if [ -x ~/bin/${INSTALLDTBS} ]; then exec ~/bin/${INSTALLDTBS} "$@"; fi
+if [ -x /sbin/${INSTALLDTBS} ]; then exec /sbin/${INSTALLDTBS} "$@"; fi
+
+# Default install
+[ -d "$2" ] && rm -rf "$2"
+
+mkdir -p "$2"
+
+for dtb in `find "$3" -name "*.dtb"`; do
+	cp "$dtb" "$2/${dtb##*/}"
+done
-- 
1.8.4.4