kbuild: add %.dtb.S and %.dtb to 'targets' automatically

Another common pattern that consists of chained commands is to compile
a DTB as binary data into the kernel image or a module.  It is used in
several places in the source tree.  Support it in the core Makefile.

$(call if_changed,dt_S_dtb) is more suitable than $(call cmd,dt_S_dtb)
in case cmd_dt_S_dtb is changed in the future.

Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
Acked-by: Frank Rowand <frowand.list@gmail.com>

2 files changed, 5 insertions, 3 deletions

diff --git a/scripts/Makefile.build b/scripts/Makefile.build
index 36f7990c5701..15b3bbb3248b 100644
--- a/scripts/Makefile.build
+++ b/scripts/Makefile.build
@@ -544,9 +544,11 @@ targets := $(filter-out $(PHONY), $(targets))
 intermediate_targets = $(foreach sfx, $(2), \
                                 $(patsubst %$(strip $(1)),%$(sfx), \
                                         $(filter %$(strip $(1)), $(targets))))
+# %.dtb.o <- %.dtb.S <- %.dtb <- %.dts
 # %.lex.o <- %.lex.c <- %.l
 # %.tab.o <- %.tab.[ch] <- %.y
-targets += $(call intermediate_targets, .lex.o, .lex.c) \
+targets += $(call intermediate_targets, .dtb.o, .dtb.S .dtb) \
+           $(call intermediate_targets, .lex.o, .lex.c) \
            $(call intermediate_targets, .tab.o, .tab.c .tab.h)
 
 # Descending
diff --git a/scripts/Makefile.lib b/scripts/Makefile.lib
index b1d938fab73b..7f5bca0c3b7b 100644
--- a/scripts/Makefile.lib
+++ b/scripts/Makefile.lib
@@ -279,8 +279,8 @@ cmd_dt_S_dtb=						\
         echo '.balign STRUCT_ALIGNMENT';                \
 ) > $@
 
-$(obj)/%.dtb.S: $(obj)/%.dtb
-        $(call cmd,dt_S_dtb)
+$(obj)/%.dtb.S: $(obj)/%.dtb FORCE
+        $(call if_changed,dt_S_dtb)
 
 quiet_cmd_dtc = DTC     $@
 cmd_dtc = mkdir -p $(dir ${dtc-tmp}) ; \