[PATCH V5 4/5] kbuild: Add support to build overlays (%.dtbo)

[Viresh Kumar]

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.ku...@linaro.org>
---
 .gitignore               | 3 +--
 Makefile                 | 4 ++--
 scripts/Makefile.dtbinst | 3 +++
 scripts/Makefile.lib     | 4 +++-
 4 files changed, 9 insertions(+), 5 deletions(-)

diff --git a/.gitignore b/.gitignore
index d01cda8e1177..0458c36f3cb2 100644
--- a/.gitignore
+++ b/.gitignore
@@ -17,8 +17,7 @@
 *.bz2
 *.c.[012]*.*
 *.dt.yaml
-*.dtb
-*.dtb.S
+*.dtb*
 *.dwo
 *.elf
 *.gcno
diff --git a/Makefile b/Makefile
index 9e73f82e0d86..b84f5e0b46ab 100644
--- a/Makefile
+++ b/Makefile
@@ -1334,7 +1334,7 @@ endif
 
 ifneq ($(dtstree),)
 
-%.dtb: include/config/kernel.release scripts_dtc
+%.dtb %.dtbo: include/config/kernel.release scripts_dtc
        $(Q)$(MAKE) $(build)=$(dtstree) $(dtstree)/$@
 
 PHONY += dtbs dtbs_install dtbs_check
@@ -1816,7 +1816,7 @@ 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)/%,$@)
diff --git a/scripts/Makefile.lib b/scripts/Makefile.lib
index 213677a5ed33..30bc0a8e0087 100644
--- a/scripts/Makefile.lib
+++ b/scripts/Makefile.lib
@@ -86,7 +86,9 @@ extra-$(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
@@ -324,7 +326,7 @@ cmd_dtc = $(HOSTCC) -E $(dtc_cpp_flags) -x 
assembler-with-cpp -o $(dtc-tmp) $< ;
                -d $(depfile).dtc.tmp $(dtc-tmp) ; \
        cat $(depfile).pre.tmp $(depfile).dtc.tmp > $(depfile)
 
-$(obj)/%.dtb: $(src)/%.dts $(DTC) FORCE
+$(obj)/%.dtb $(obj)/%.dtbo: $(src)/%.dts $(DTC) FORCE
        $(call if_changed_dep,dtc)
 
 DT_CHECKER ?= dt-validate
-- 
2.25.0.rc1.19.g042ed3e048af