[openwrt/openwrt] image: improve uImage.FIT device tree overlay support

[LEDE Commits]

dangole pushed a commit to openwrt/openwrt.git, branch openwrt-23.05:
https://git.openwrt.org/d05d886d22ed1f395d7d4ee47b2e2075b58fa9b9

commit d05d886d22ed1f395d7d4ee47b2e2075b58fa9b9
Author: Daniel Golle <daniel at makrotopia.org>
AuthorDate: Sun Jun 4 15:57:25 2023 +0100

    image: improve uImage.FIT device tree overlay support
    
    Instead of generating full config nodes incl. kernel, generate minimal
    config nodes for device tree overlays to be applied to the main config.
    In this way, multiple device tree overlays can be applied more easily.
    While at it change filenames to upstream style, ie. use dtso and dtbo
    suffix for device tree overlays.
    
    Signed-off-by: Daniel Golle <daniel at makrotopia.org>
    (cherry picked from commit 6b01d40bfedb42323a1324e1b5624f192a4c91de)
---
 include/image-commands.mk |  2 +-
 include/image.mk          | 19 ++++++++++++++++++-
 scripts/mkits.sh          |  9 +++------
 3 files changed, 22 insertions(+), 8 deletions(-)

diff --git a/include/image-commands.mk b/include/image-commands.mk
index ea602662a5..1d69485019 100644
--- a/include/image-commands.mk
+++ b/include/image-commands.mk
@@ -307,7 +307,7 @@ define Build/fit
 		$(if $(DEVICE_FDT_NUM),-n $(DEVICE_FDT_NUM)) \
 		$(if $(DEVICE_DTS_DELIMITER),-l $(DEVICE_DTS_DELIMITER)) \
 		$(if $(DEVICE_DTS_LOADADDR),-s $(DEVICE_DTS_LOADADDR)) \
-		$(if $(DEVICE_DTS_OVERLAY),$(foreach dtso,$(DEVICE_DTS_OVERLAY), -O $(dtso):$(KERNEL_BUILD_DIR)/image-$(dtso).dtb)) \
+		$(if $(DEVICE_DTS_OVERLAY),$(foreach dtso,$(DEVICE_DTS_OVERLAY), -O $(dtso):$(KERNEL_BUILD_DIR)/image-$(dtso).dtbo)) \
 		-c $(if $(DEVICE_DTS_CONFIG),$(DEVICE_DTS_CONFIG),"config-1") \
 		-A $(LINUX_KARCH) -v $(LINUX_VERSION)
 	PATH=$(LINUX_DIR)/scripts/dtc:$(PATH) mkimage $(if $(findstring external,$(word 3,$(1))),\
diff --git a/include/image.mk b/include/image.mk
index 0eae216ded..0cf110df93 100644
--- a/include/image.mk
+++ b/include/image.mk
@@ -554,16 +554,33 @@ define Device/Build/dtb
   image_prepare: $(KDIR)/image-$(1).dtb
   endif
 
+endef
+
+define Device/Build/dtbo
+  ifndef BUILD_DTS_$(1)
+  BUILD_DTS_$(1) := 1
+  $(KDIR)/image-$(1).dtbo: FORCE
+	$(call Image/BuildDTB,$(strip $(2))/$(strip $(3)).dtso,$$@)
+
+  image_prepare: $(KDIR)/image-$(1).dtbo
+  endif
+
 endef
 endif
 
 define Device/Build/kernel
-  $$(eval $$(foreach dts,$$(DEVICE_DTS) $$(DEVICE_DTS_OVERLAY), \
+  $$(eval $$(foreach dts,$$(DEVICE_DTS), \
 	$$(call Device/Build/dtb,$$(notdir $$(dts)), \
 		$$(if $$(DEVICE_DTS_DIR),$$(DEVICE_DTS_DIR),$$(DTS_DIR)), \
 		$$(dts) \
 	) \
   ))
+  $$(eval $$(foreach dtso,$$(DEVICE_DTS_OVERLAY), \
+	$$(call Device/Build/dtbo,$$(notdir $$(dtso)), \
+		$$(if $$(DEVICE_DTS_DIR),$$(DEVICE_DTS_DIR),$$(DTS_DIR)), \
+		$$(dtso) \
+	) \
+  ))
 
   $(KDIR)/$$(KERNEL_NAME):: image_prepare
   $$(_TARGET): $$(if $$(KERNEL_INSTALL),$(BIN_DIR)/$$(KERNEL_IMAGE))
diff --git a/scripts/mkits.sh b/scripts/mkits.sh
index bf75d69f09..b1c6f98867 100755
--- a/scripts/mkits.sh
+++ b/scripts/mkits.sh
@@ -191,13 +191,10 @@ OVCONFIGS=""
 "
 	OVCONFIGS="$OVCONFIGS
 
-		config-$ovname {
-			description = \"OpenWrt ${DEVICE} with $ovname\";
-			kernel = \"kernel${REFERENCE_CHAR}1\";
-			fdt = \"fdt${REFERENCE_CHAR}$FDTNUM\", \"$ovnode\";
-			${LOADABLES:+loadables = ${LOADABLES};}
+		$ovname {
+			description = \"OpenWrt ${DEVICE} overlay $ovname\";
+			fdt = \"$ovnode\";
 			${COMPATIBLE_PROP}
-			${INITRD_PROP}
 		};
 	"
 done