ARM64: add option to build Image.gz/dtb combo

Allows a defconfig to set a list of dtbs to concatenate with an
Image.gz to create a Image.gz-dtb.

Includes 8adb162 arm64: Fix correct dtb clean-files location

Change-Id: I0b462322d5c970f1fdf37baffece7ad058099f4a
Signed-off-by: Alex Ray <aray@google.com>

arch/arm64/Kconfig

@@ -707,6 +707,21 @@ config DMI
 	  However, even with this option, the resultant kernel should
 	  continue to boot on existing non-UEFI platforms.
 
+config BUILD_ARM64_APPENDED_DTB_IMAGE
+	bool "Build a concatenated Image.gz/dtb by default"
+	depends on OF
+	help
+	  Enabling this option will cause a concatenated Image.gz and list of
+	  DTBs to be built by default (instead of a standalone Image.gz.)
+	  The image will built in arch/arm64/boot/Image.gz-dtb
+
+config BUILD_ARM64_APPENDED_DTB_IMAGE_NAMES
+	string "Default dtb names"
+	depends on BUILD_ARM64_APPENDED_DTB_IMAGE
+	help
+	  Space separated list of names of dtbs to append when
+	  building a concatenated Image.gz-dtb.
+
 endmenu
 
 menu "Userspace binary formats"

arch/arm64/Makefile

@@ -51,7 +51,12 @@ libs-y		:= arch/arm64/lib/ $(libs-y)
 core-$(CONFIG_EFI_STUB) += $(objtree)/drivers/firmware/efi/libstub/lib.a
 
 # Default target when executing plain make
+ifeq ($(CONFIG_BUILD_ARM64_APPENDED_DTB_IMAGE),y)
+KBUILD_IMAGE	:= Image.gz-dtb
+else
 KBUILD_IMAGE	:= Image.gz
+endif
+
 KBUILD_DTBS	:= dtbs
 
 all:	$(KBUILD_IMAGE) $(KBUILD_DTBS)
@@ -75,6 +80,9 @@ dtbs: prepare scripts
 dtbs_install:
 	$(Q)$(MAKE) $(dtbinst)=$(boot)/dts
 
+Image.gz-dtb: vmlinux scripts dtbs
+	$(Q)$(MAKE) $(build)=$(boot) $(boot)/$@
+
 PHONY += vdso_install
 vdso_install:
 	$(Q)$(MAKE) $(build)=arch/arm64/kernel/vdso $@

arch/arm64/boot/.gitignore

@@ -1,2 +1,3 @@
 Image
 Image.gz
+Image.gz-dtb

arch/arm64/boot/Makefile

@@ -14,14 +14,27 @@
 # Based on the ia64 boot/Makefile.
 #
 
+include $(srctree)/arch/arm64/boot/dts/Makefile
+
 targets := Image Image.gz
 
+DTB_NAMES := $(subst $\",,$(CONFIG_BUILD_ARM64_APPENDED_DTB_IMAGE_NAMES))
+ifneq ($(DTB_NAMES),)
+DTB_LIST := $(addsuffix .dtb,$(DTB_NAMES))
+else
+DTB_LIST := $(dtb-y)
+endif
+DTB_OBJS := $(addprefix $(obj)/dts/,$(DTB_LIST))
+
 $(obj)/Image: vmlinux FORCE
 	$(call if_changed,objcopy)
 
 $(obj)/Image.gz: $(obj)/Image FORCE
 	$(call if_changed,gzip)
 
+$(obj)/Image.gz-dtb: $(obj)/Image.gz $(DTB_OBJS) FORCE
+	$(call if_changed,cat)
+
 install: $(obj)/Image
 	$(CONFIG_SHELL) $(srctree)/$(src)/install.sh $(KERNELRELEASE) \
 	$(obj)/Image System.map "$(INSTALL_PATH)"

arch/arm64/boot/dts/Makefile

@@ -10,3 +10,17 @@ dts-dirs += sprd
 dts-dirs += xilinx
 
 subdir-y	:= $(dts-dirs)
+
+targets += dtbs
+
+DTB_NAMES := $(subst $\",,$(CONFIG_BUILD_ARM64_APPENDED_DTB_IMAGE_NAMES))
+ifneq ($(DTB_NAMES),)
+DTB_LIST := $(addsuffix .dtb,$(DTB_NAMES))
+else
+DTB_LIST := $(dtb-y)
+endif
+targets += $(DTB_LIST)
+
+dtbs: $(addprefix $(obj)/, $(DTB_LIST))
+
+clean-files := dts/*.dtb *.dtb