[PATCH V6 4/6] kbuild: Add support to build overlays (%.dtbo)

[Viresh Kumar <viresh.kumar@linaro.org>]

Add support for building DT overlays (%.dtbo). The overlay's source file
will have the usual extension, i.e. .dts, though the blob will have
.dtbo extension to distinguish it from normal blobs.

Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
---
 .gitignore               | 1 +
 Makefile                 | 5 ++++-
 scripts/Makefile.dtbinst | 3 +++
 scripts/Makefile.lib     | 5 +++++
 4 files changed, 13 insertions(+), 1 deletion(-)

diff --git a/.gitignore b/.gitignore
index d01cda8e1177..bb65fa253e58 100644
--- a/.gitignore
+++ b/.gitignore
@@ -18,6 +18,7 @@
 *.c.[012]*.*
 *.dt.yaml
 *.dtb
+*.dtbo
 *.dtb.S
 *.dwo
 *.elf
diff --git a/Makefile b/Makefile
index 9e73f82e0d86..18fd02f55d9b 100644
--- a/Makefile
+++ b/Makefile
@@ -1337,6 +1337,9 @@ ifneq ($(dtstree),)
 %.dtb: include/config/kernel.release scripts_dtc
 	$(Q)$(MAKE) $(build)=$(dtstree) $(dtstree)/$@
 
+%.dtbo: include/config/kernel.release scripts_dtc
+	$(Q)$(MAKE) $(build)=$(dtstree) $(dtstree)/$@
+
 PHONY += dtbs dtbs_install dtbs_check
 dtbs: include/config/kernel.release scripts_dtc
 	$(Q)$(MAKE) $(build)=$(dtstree)
@@ -1816,7 +1819,7 @@ clean: $(clean-dirs)
 	@find $(if $(KBUILD_EXTMOD), $(KBUILD_EXTMOD), .) $(RCS_FIND_IGNORE) \
 		\( -name '*.[aios]' -o -name '*.ko' -o -name '.*.cmd' \
 		-o -name '*.ko.*' \
-		-o -name '*.dtb' -o -name '*.dtb.S' -o -name '*.dt.yaml' \
+		-o -name '*.dtb' -o -name '*.dtbo' -o -name '*.dtb.S' -o -name '*.dt.yaml' \
 		-o -name '*.dwo' -o -name '*.lst' \
 		-o -name '*.su' -o -name '*.mod' \
 		-o -name '.*.d' -o -name '.*.tmp' -o -name '*.mod.c' \
diff --git a/scripts/Makefile.dtbinst b/scripts/Makefile.dtbinst
index 50d580d77ae9..ba01f5ba2517 100644
--- a/scripts/Makefile.dtbinst
+++ b/scripts/Makefile.dtbinst
@@ -29,6 +29,9 @@ quiet_cmd_dtb_install = INSTALL $@
 $(dst)/%.dtb: $(obj)/%.dtb
 	$(call cmd,dtb_install)
 
+$(dst)/%.dtbo: $(obj)/%.dtbo
+	$(call cmd,dtb_install)
+
 PHONY += $(subdirs)
 $(subdirs):
 	$(Q)$(MAKE) $(dtbinst)=$@ dst=$(patsubst $(obj)/%,$(dst)/%,$@)
diff --git a/scripts/Makefile.lib b/scripts/Makefile.lib
index 213677a5ed33..b00855b247e0 100644
--- a/scripts/Makefile.lib
+++ b/scripts/Makefile.lib
@@ -86,7 +86,9 @@ extra-$(CONFIG_OF_ALL_DTBS)	+= $(dtb-)
 
 ifneq ($(CHECK_DTBS),)
 extra-y += $(patsubst %.dtb,%.dt.yaml, $(dtb-y))
+extra-y += $(patsubst %.dtbo,%.dt.yaml, $(dtb-y))
 extra-$(CONFIG_OF_ALL_DTBS) += $(patsubst %.dtb,%.dt.yaml, $(dtb-))
+extra-$(CONFIG_OF_ALL_DTBS) += $(patsubst %.dtbo,%.dt.yaml, $(dtb-))
 endif
 
 # Add subdir path
@@ -327,6 +329,9 @@ cmd_dtc = $(HOSTCC) -E $(dtc_cpp_flags) -x assembler-with-cpp -o $(dtc-tmp) $< ;
 $(obj)/%.dtb: $(src)/%.dts $(DTC) FORCE
 	$(call if_changed_dep,dtc)
 
+$(obj)/%.dtbo: $(src)/%.dts $(DTC) FORCE
+	$(call if_changed_dep,dtc)
+
 DT_CHECKER ?= dt-validate
 DT_BINDING_DIR := Documentation/devicetree/bindings
 # DT_TMP_SCHEMA may be overridden from Documentation/devicetree/bindings/Makefile
-- 
2.25.0.rc1.19.g042ed3e048af