freedom-u540: Allow u-boot to be an OpenSBI payload

Signed-off-by: Alistair Francis <alistair.francis@wdc.com>

conf/machine/freedom-u540.conf

@@ -7,7 +7,6 @@ require conf/machine/include/tune-riscv.inc
 
 MACHINE_FEATURES = "screen keyboard ext2 ext3 serial"
 
-# This must be vmlinux for bbl to work and Image for openSBI
 KERNEL_IMAGETYPE = "Image"
 
 PREFERRED_PROVIDER_virtual/kernel ?= "linux-riscv"
@@ -16,10 +15,13 @@ GDBVERSION = "riscv"
 
 EXTRA_IMAGEDEPENDS += "opensbi"
 RISCV_SBI_PLAT = "sifive/fu540"
-# When we have better openSBI -> u-boot -> kernel support in released
-#  versions of u-boot and Linux kernel swap to u-boot binary here.
-# RISCV_SBI_PAYLOAD ?= "u-boot-${MACHINE}.bin"
+
+# When we have u-boot SD/MMC load support we can swap to
+#  u-boot being the defual. Until then it's an option for TFTP boot
+# RISCV_SBI_PAYLOAD ?= "u-boot.bin"
+# This will set the kernel as the OpenSBI payload
 RISCV_SBI_PAYLOAD ?= "${KERNEL_IMAGETYPE}-${MACHINE}.bin"
+
 # Override the DTB from the firmware with this one from openSBI
 # Use this to add Microsemi Expansion board support
 # RISCV_SBI_FDT ?= "HiFiveUnleashed-MicroSemi-Expansion.dtb"
@@ -29,10 +31,15 @@ SERIAL_CONSOLES = "115200;ttySIF0"
 MACHINE_EXTRA_RRECOMMENDS += " kernel-modules"
 
 IMAGE_FSTYPES_append = " wic.gz ext4"
+KERNEL_IMAGETYPES += "uImage"
+KEEPUIMAGE = "no"
 
 # Do not update fstab file when using wic images
 WIC_CREATE_EXTRA_ARGS ?= "--no-fstab-update"
 
+EXTRA_IMAGEDEPENDS += "u-boot"
+UBOOT_MACHINE = "sifive_fu540_defconfig"
+
 ### wic default support
 WKS_FILE_DEPENDS ?= " \
     opensbi \
@@ -42,6 +49,7 @@ WKS_FILE_DEPENDS ?= " \
 
 IMAGE_BOOT_FILES ?= " \
     Image \
+    uImage \
 "
 
 WKS_FILE ?= "freedom-u540-opensbi.wks"