[PATCH 03/13] kbuild: collect available device trees in dtbs-list

[Ahmad Fatoum <a.fatoum@pengutronix.de>]

Now that we have a dtb-y variable containing all board device trees,
let's import some Linux Kbuild code, so barebox can also maintain a list
of built device trees in arch/$ARCH/dts/dtbs-list.

Signed-off-by: Ahmad Fatoum <a.fatoum@pengutronix.de>
---
 .gitignore             |  1 +
 Makefile               |  1 +
 scripts/Makefile.build | 11 +++++++++++
 scripts/Makefile.dtbs  | 32 ++++++++++++++++++++++++++++++++
 4 files changed, 45 insertions(+)
 create mode 100644 scripts/Makefile.dtbs

diff --git a/.gitignore b/.gitignore
index 5e1b0c2b68ff..0bee67af4881 100644
--- a/.gitignore
+++ b/.gitignore
@@ -36,6 +36,7 @@
 *.tab.[ch]
 binary.0
 Module.symvers
+dtbs-list
 *.dtb
 *.dtb.*
 *.dtbo
diff --git a/Makefile b/Makefile
index d5d02f4efe15..5f5f830af5d2 100644
--- a/Makefile
+++ b/Makefile
@@ -1238,6 +1238,7 @@ clean: archclean $(clean-dirs)
 		\( -name '*.[oas]' -o -name '*.ko' -o -name '.*.cmd' \
 		-o -name '.*.d' -o -name '.*.tmp' -o -name '*.mod.c' \
 		-o -name '*lex.c' -o -name '.tab.[ch]' \
+		-o -name 'dtbs-list' \
 		-o -name '*.symtypes' -o -name '*.bbenv.*' -o -name "*.bbenv" \) \
 		-type f -print | xargs rm -f
 
diff --git a/scripts/Makefile.build b/scripts/Makefile.build
index 1c511d38a12b..591da3d750ec 100644
--- a/scripts/Makefile.build
+++ b/scripts/Makefile.build
@@ -56,12 +56,23 @@ ifneq ($(userprogs),)
 include scripts/Makefile.userprogs
 endif
 
+ifneq ($(need-dtbslist)$(dtb-y)$(dtb-)$(filter %.dtb %.dtb.o %.dtbo.o,$(targets)),)
+include $(srctree)/scripts/Makefile.dtbs
+endif
+
 ifndef obj
 $(warning kbuild: Makefile.build is included improperly)
 endif
 
 # ===========================================================================
 
+# This is a list of build artifacts from the current Makefile and its
+# sub-directories. The timestamp should be updated when any of the member files.
+
+cmd_gen_order = { $(foreach m, $(real-prereqs), \
+	$(if $(filter %/$(notdir $@), $m), cat $m, echo $m);) :; } \
+	> $@
+
 ifneq ($(strip $(lib-y) $(lib-m) $(lib-n) $(lib-)),)
 lib-target := $(obj)/lib.a
 endif
diff --git a/scripts/Makefile.dtbs b/scripts/Makefile.dtbs
new file mode 100644
index 000000000000..046361c20a6a
--- /dev/null
+++ b/scripts/Makefile.dtbs
@@ -0,0 +1,32 @@
+# SPDX-License-Identifier: GPL-2.0-only
+
+# If CONFIG_OF_ALL_DTBS is enabled, all DT blobs are built
+dtb-$(CONFIG_OF_ALL_DTBS) += $(dtb-)
+
+# Composite DTB (i.e. DTB constructed by overlay)
+multi-dtb-y := $(call multi-search, $(dtb-y), .dtb, -dtbs)
+# Primitive DTB compiled from *.dts
+real-dtb-y := $(call real-search, $(dtb-y), .dtb, -dtbs)
+# Base DTB that overlay is applied onto
+base-dtb-y := $(filter %.dtb, $(call real-search, $(multi-dtb-y), .dtb, -dtbs))
+
+dtb-y           := $(addprefix $(obj)/, $(dtb-y))
+multi-dtb-y     := $(addprefix $(obj)/, $(multi-dtb-y))
+real-dtb-y      := $(addprefix $(obj)/, $(real-dtb-y))
+
+always-y        += $(dtb-y)
+targets         += $(real-dtb-y)
+
+# dtbs-list
+# ---------------------------------------------------------------------------
+
+ifdef need-dtbslist
+subdir-dtbslist := $(addsuffix /dtbs-list, $(subdir-ym))
+dtb-y           += $(subdir-dtbslist)
+always-y        += $(obj)/dtbs-list
+endif
+
+$(subdir-dtbslist): $(obj)/%/dtbs-list: $(obj)/% ;
+
+$(obj)/dtbs-list: $(dtb-y) FORCE
+	$(call if_changed,gen_order)
-- 
2.39.5