adding fdt-overlay function - help needed

[Frank Wunderlich]

Hi,

i try to get overlay-merging working in uboot (for OF_UPSTREAM conversion), but failing on missing Makefile knowledge

i have the state now, that upstream dtso get compiled to dtbo files (that needed further changes).

now i added this from linux-tree:

#merge CONFIG_DEFAULT_DEVICE_TREE + OF_OVERLAY_LIST_BASEDT to target DTB
#manual:
# dtc -I dtb -O dts dts/upstream/src/arm64/mediatek/mt7986a-bananapi-bpi-r3-sd.dtbo
# fdtoverlay -i dts/upstream/src/arm64/mediatek/mt7986a-bananapi-bpi-r3.dtb -o dts/upstream/src/arm64/mediatek/mt7986a-bananapi-bpi-r3-sd.dtb dts/upstream/src/arm64/mediatek/mt7986a-bananapi-bpi-r3-sd.dtbo
# dtc -I dtb -O dts dts/upstream/src/arm64/mediatek/mt7986a-bananapi-bpi-r3-sd.dtb | less

#currently linux-version
quiet_cmd_fdtoverlay = DTOVL   $@
      cmd_fdtoverlay = $(objtree)/scripts/dtc/fdtoverlay -o $@ -i $(real-prereqs)

$(multi-dtb-y): FORCE
	$(call if_changed,fdtoverlay)
$(call multi_depend, $(multi-dtb-y), .dtb, -dtbs)

and created an config-option CONFIG_OF_OVERLAY_LIST_BASEDT which holds a space separated list of the dtbo-files without path, in my test

CONFIG_DEFAULT_DEVICE_TREE="mediatek/mt7986a-bananapi-bpi-r3"
CONFIG_OF_OVERLAY_LIST_BASEDT="mt7986a-bananapi-bpi-r3-nand.dtbo mt7986a-bananapi-bpi-r3-nor.dtbo mt7986a-bananapi-bpi-r3-sd.dtbo"

i now want the list passed to the quiet_cmd_fdtoverlay which should handle each item and add the dtbo to a base-devicetree (like in comments above)....

maybe anyone here can help getting this to work?

if my source is needed: https://github.com/frank-w/u-boot/commits/2024-07-bpi-ofupstream-all/

regards Frank