Add device tree overlay support in Linux, U-Boot, and post image script

board/raspberrypi/post-image.sh

@@ -20,6 +20,10 @@ if [ ! -e "${GENIMAGE_CFG}" ]; then
 		FILES+=( "${i#${BINARIES_DIR}/}" )
 	done
 
+	for i in "${BINARIES_DIR}"/*.dtbo; do
+		FILES+=( "${i#${BINARIES_DIR}/}" )
+	done
+
 	FILES+=( "u-boot.bin" )
 	FILES+=( "zImage" )
 	FILES+=( "extlinux/" )

board/raspberrypi/uboot-patches/0001-rpi-add-fdtoverlay_addr_r-to-support-DT-overlays.patch

@@ -0,0 +1,10 @@
+--- a/board/raspberrypi/rpi/rpi.env
++++ b/board/raspberrypi/rpi/rpi.env
+@@ -75,6 +75,7 @@
+ scriptaddr=0x05400000
+ pxefile_addr_r=0x05500000
+ fdt_addr_r=0x05600000
++fdtoverlay_addr_r=0x056A0000
+ ramdisk_addr_r=0x05700000
+ 
+ boot_targets=mmc usb pxe dhcp

configs/raspberrypi_common_defconfig

@@ -13,9 +13,12 @@ BR2_ROOTFS_POST_IMAGE_SCRIPT="$(BR2_EXTERNAL_RPI_COMMON_PATH)/board/raspberrypi/
 BR2_LINUX_KERNEL=y
 BR2_LINUX_KERNEL_CUSTOM_VERSION=y
 BR2_LINUX_KERNEL_CUSTOM_VERSION_VALUE="6.12.74"
-BR2_LINUX_KERNEL_DEFCONFIG="bcm2835"
+BR2_LINUX_KERNEL_USE_CUSTOM_CONFIG=y
+BR2_LINUX_KERNEL_CUSTOM_CONFIG_FILE="$(BR2_EXTERNAL_RPI_COMMON_PATH)/board/raspberrypi/linux_defconfig"
 BR2_LINUX_KERNEL_DTS_SUPPORT=y
 BR2_LINUX_KERNEL_INTREE_DTS_NAME="broadcom/bcm2835-rpi-b-plus"
+BR2_LINUX_KERNEL_CUSTOM_DTS_DIR="$(BR2_EXTERNAL_RPI_COMMON_PATH)/board/raspberrypi/dtoverlay/"
+BR2_LINUX_KERNEL_DTB_OVERLAY_SUPPORT=y
 BR2_LINUX_KERNEL_NEEDS_HOST_OPENSSL=y
 BR2_PACKAGE_BUSYBOX_SHOW_OTHERS=y
 BR2_PACKAGE_XZ=y