RISC-V: enable building for Nezha board

Signed-off-by: Heinrich Schuchardt <heinrich.schuchardt@canonical.com>

live-build/auto/config

@@ -938,7 +938,14 @@ case $PROJECT in
 				;;
 			riscv64*)
 				if [ -n "$SUBARCH" ]; then
+					case "${SUBARCH:-}" in
+						nezha)
+							KERNEL_FLAVOURS=allwinner
+							;;
+						*)
 							KERNEL_FLAVOURS=generic
+							;;
+					esac
 				fi
 				;;
 		esac

live-build/ubuntu-cpc/hooks.d/base/disk-image-uefi.binary

@@ -209,6 +209,26 @@ install_grub() {
             chroot mountpoint u-boot-update
 
             if [ -n "${SUBARCH:-}" ]; then
+                case "${SUBARCH}" in
+                    "nezha")
+                        echo "Installing U-Boot for Nezha board" &1>2
+                        chroot mountpoint apt-get install -qqy nezha-boot0
+                        # FSBL, which gets U-Boot SPL
+                        loader1="/dev/mapper${loop_device///dev/}p13"
+                        dd if=mountpoint/usr/lib/u-boot/nezha/boot0_sdcard_sun20iw1p1.bin of=$loader1
+                        # The real U-Boot
+                        chroot mountpoint apt-get install -qqy u-boot-nezha
+                        loader2="/dev/mapper${loop_device///dev/}p14"
+                        dd if=mountpoint/usr/lib/u-boot/nezha/u-boot.toc1 of=$loader2
+                        # Provide end-user modifyable CIDATA
+                        cidata_dev="/dev/mapper${loop_device///dev/}p12"
+                        setup_cidata "${cidata_dev}"
+                        # Provide stock nocloud datasource
+                        # Allow interactive login on baremetal SiFive board,
+                        # without a cloud datasource.
+                        setup_cinocloud mountpoint
+                        ;;
+                    *)
                         u_boot_arch="${SUBARCH}"
                         if [ "${u_boot_arch}" = "hifive" ]; then
                             u_boot_arch=sifive_fu540
@@ -227,7 +247,10 @@ install_grub() {
                         # Allow interactive login on baremetal SiFive board,
                         # without a cloud datasource.
                         setup_cinocloud mountpoint
+                        ;;
+                esac
             fi
+
             ## TODO remove below once we have grub-efi-riscv64
             rm mountpoint/tmp/device.map
             umount mountpoint/boot/efi