[PATCH v3 1/7] kbuild: Add target to build dtb overlay files

[Sascha Hauer]

Device tree overlay files have the suffix dtso in source format
and dtbo in binary format. Add the necessary targets to build dtbo
files from dtso files and also dtbo.o files to include into the
barebox binary.
The overlay files shouldn't include the device tree snippets from
CONFIG_EXTERNAL_DTS_FRAGMENTS which makes it necessary to specify
these fragments as an argument to cmd_dtc.

Signed-off-by: Sascha Hauer <s.hauer at pengutronix.de>
---
 scripts/Makefile.build |  2 ++
 scripts/Makefile.lib   | 10 +++++++++-
 scripts/gen-dtbo-s     | 14 ++++++++++++++
 3 files changed, 25 insertions(+), 1 deletion(-)
 create mode 100755 scripts/gen-dtbo-s

diff --git a/scripts/Makefile.build b/scripts/Makefile.build
index 216f03677b..25347eee01 100644
--- a/scripts/Makefile.build
+++ b/scripts/Makefile.build
@@ -258,11 +258,13 @@ intermediate_targets = $(foreach sfx, $(2), \
 					$(filter %$(strip $(1)), $(targets))))
 # %.asn1.o <- %.asn1.[ch] <- %.asn1
 # %.dtb.o <- %.dtb.S <- %.dtb <- %.dts
+# %.dtbo.o <- %.dtbo.S <- %.dtbo <- %.dtso
 # %.dtb.pbl.o <- %.dtb.S <- %.dtb <- %.dts (Barebox only)
 # %.lex.o <- %.lex.c <- %.l
 # %.tab.o <- %.tab.[ch] <- %.y
 targets += $(call intermediate_targets, .asn1.o, .asn1.c .asn1.h) \
 	   $(call intermediate_targets, .dtb.o, .dtb.S .dtb.z .dtb) \
+	   $(call intermediate_targets, .dtbo.o, .dtbo.S .dtbo.z .dtbo) \
 	   $(call intermediate_targets, .dtb.pbl.o, .dtb.S .dtb.z .dtb) \
 	   $(call intermediate_targets, .lex.o, .lex.c) \
 	   $(call intermediate_targets, .tab.o, .tab.c .tab.h)
diff --git a/scripts/Makefile.lib b/scripts/Makefile.lib
index 6e0d92cf75..42c59a072c 100644
--- a/scripts/Makefile.lib
+++ b/scripts/Makefile.lib
@@ -361,13 +361,18 @@ cmd_dt_S_dtb = $(srctree)/scripts/gen-dtb-s $(subst -,_,$(*F)) $< $(CONFIG_IMD)
 $(obj)/%.dtb.S: $(obj)/%.dtb $(obj)/%.dtb.z $(srctree)/scripts/gen-dtb-s FORCE
 	$(call if_changed,dt_S_dtb)
 
+quiet_cmd_dt_S_dtbo = DTBO    $@
+cmd_dt_S_dtbo = $(srctree)/scripts/gen-dtbo-s $(subst -,_,$(*F)) $< > $@
+$(obj)/%.dtbo.S: $(obj)/%.dtbo $(srctree)/scripts/gen-dtbo-s FORCE
+	$(call if_changed,dt_S_dtbo)
+
 $(obj)/%.dtb.z: $(obj)/%.dtb FORCE
 	$(call if_changed,$(suffix_y))
 
 dts-frags = $(subst $(quote),,$(CONFIG_EXTERNAL_DTS_FRAGMENTS))
 quiet_cmd_dtc = DTC     $@
 # For compatibility between make 4.2 and 4.3
-cmd_dtc = /usr/bin/env echo -e '$(pound)define $(subst -,_,$(*F))_dts 1\n'$(foreach f,$< $(dts-frags),'$(pound)include "$(f)"\n') | \
+cmd_dtc = /usr/bin/env echo -e '$(pound)define $(subst -,_,$(*F))_dts 1\n'$(foreach f,$< $(2),'$(pound)include "$(f)"\n') | \
 	$(CPP) $(dtc_cpp_flags) -x assembler-with-cpp -o $(dtc-tmp) - ; \
 	$(objtree)/scripts/dtc/dtc -O dtb -o $@ -b 0 \
 		-i $(srctree)/arch/$(SRCARCH)/dts $(DTC_FLAGS) \
@@ -376,6 +381,9 @@ cmd_dtc = /usr/bin/env echo -e '$(pound)define $(subst -,_,$(*F))_dts 1\n'$(fore
 	cat $(depfile).pre $(depfile).dtc > $(depfile)
 
 $(obj)/%.dtb: $(src)/%.dts FORCE
+	$(call if_changed_dep,dtc,$(dts-frags))
+
+$(obj)/%.dtbo: $(src)/%.dtso $(DTC) FORCE
 	$(call if_changed_dep,dtc)
 
 dtc-tmp = $(subst $(comma),_,$(dot-target).dts)
diff --git a/scripts/gen-dtbo-s b/scripts/gen-dtbo-s
new file mode 100755
index 0000000000..06f78609ed
--- /dev/null
+++ b/scripts/gen-dtbo-s
@@ -0,0 +1,14 @@
+#!/usr/bin/env bash
+
+name=$1
+dtbo=$2
+
+echo "#include <asm/barebox.lds.h>"
+
+echo ".section .dtb.rodata.${name}_dtbo,\"a\""
+echo ".balign STRUCT_ALIGNMENT"
+echo ".global __dtbo_${name}_start"
+echo "__dtbo_${name}_start:"
+echo ".incbin \"$dtbo\""
+echo "__dtbo_${name}_end:"
+echo ".global __dtbo_${name}_end"
-- 
2.30.2