Add support for AArch64/ARM64 EFI architecture (#1757)

* Add AArch64/ARM64 EFI boot support (for QEMU and some boards)
* Allow GRUB to load cmdline.txt-like
* Enable qcow2/vmdk disk images

Co-authored-by: Stefan Agner <stefan@agner.ch>

buildroot-external/board/arm-uefi/generic-aarch64/cmdline.txt

@@ -0,0 +1 @@
+cmdline=""

buildroot-external/board/arm-uefi/generic-aarch64/grub.cfg

@@ -0,0 +1,59 @@
+set default=99
+set timeout=5
+
+set ORDER="A B"
+set A_OK=0
+set B_OK=0
+set A_TRY=0
+set B_TRY=0
+set MACHINE_ID=""
+load_env
+
+# select bootable slot
+for SLOT in $ORDER; do
+    if [ "$SLOT" == "A" ]; then
+        INDEX=0
+        OK=$A_OK
+        TRY=$A_TRY
+        A_TRY=1
+    fi
+    if [ "$SLOT" == "B" ]; then
+        INDEX=1
+        OK=$B_OK
+        TRY=$B_TRY
+        B_TRY=1
+    fi
+    if [ "$OK" -eq 1 -a "$TRY" -eq 0 ]; then
+        default=$INDEX
+        break
+    fi
+done
+
+# reset booted flags
+if [ "$default" -eq 99 ]; then
+    if [ "$A_OK" -eq 1 -a "$A_TRY" -eq 1 ]; then
+        A_TRY=0
+    fi
+    if [ "$B_OK" -eq 1 -a "$B_TRY" -eq 1 ]; then
+        B_TRY=0
+    fi
+    default=0
+fi
+
+save_env A_TRY A_OK B_TRY B_OK ORDER MACHINE_ID
+
+default_cmdline="rootwait zram.enabled=1 zram.num_devices=3 apparmor=1 security=apparmor systemd.machine_id=$MACHINE_ID cgroup_enable=memory fsck.repair=yes"
+source ($root)/cmdline.txt
+
+# root is a full HDD/partition definition in GRUB format like hd0,gpt1
+# We extract the part before the comma to then append our own partition index
+# at the end. This is hacky but the best way I found
+regexp --set 1:boothd (.+),.+ ${root}
+
+menuentry "Slot A (OK=$A_OK TRY=$A_TRY)" {
+    linux (${boothd},gpt2)/Image root=PARTUUID=8d3d53e3-6d49-4c38-8349-aff6859e82fd $default_cmdline $cmdline rauc.slot=A
+}
+
+menuentry "Slot B (OK=$B_OK TRY=$B_TRY)" {
+    linux (${boothd},gpt4)/Image root=PARTUUID=a3ec664e-32ce-4665-95ea-7ae90ce9aa20 $default_cmdline $cmdline rauc.slot=B
+}

buildroot-external/board/arm-uefi/generic-aarch64/hassos-hook.sh

@@ -0,0 +1,27 @@
+#!/bin/bash
+# shellcheck disable=SC2155
+
+function hassos_pre_image() {
+    local BOOT_DATA="$(path_boot_dir)"
+    local EFIPART_DATA="${BINARIES_DIR}/efi-part"
+
+    mkdir -p "${BOOT_DATA}/EFI/BOOT"
+
+    cp "${BOARD_DIR}/grub.cfg" "${EFIPART_DATA}/EFI/BOOT/grub.cfg"
+    cp "${BOARD_DIR}/cmdline.txt" "${EFIPART_DATA}/cmdline.txt"
+    grub-editenv "${EFIPART_DATA}/EFI/BOOT/grubenv" create
+
+    cp -r "${EFIPART_DATA}/"* "${BOOT_DATA}/"
+}
+
+
+function hassos_post_image() {
+    convert_disk_image_virtual vmdk
+    convert_disk_image_virtual qcow2
+
+    convert_disk_image_zip vmdk
+    convert_disk_image_xz qcow2
+
+    convert_disk_image_xz
+}
+

buildroot-external/board/arm-uefi/generic-aarch64/kernel.config

@@ -0,0 +1,16 @@
+CONFIG_EFI_STUB=y
+
+CONFIG_VIRTIO=y
+CONFIG_VIRTIO_PCI=y
+CONFIG_VIRTIO_NET=y
+CONFIG_VIRTIO_BALLOON=m
+CONFIG_VIRTIO_INPUT=m
+CONFIG_VIRTIO_BLK=y
+CONFIG_VIRTIO_BLK_SCSI=y
+CONFIG_VIRTIO_CONSOLE=m
+CONFIG_VIRTIO_VSOCKETS=m
+CONFIG_VIRTIO_MMIO=y
+CONFIG_SCSI_VIRTIO=y
+CONFIG_HW_RANDOM_VIRTIO=y
+
+CONFIG_DRM_VIRTIO_GPU=m

buildroot-external/board/arm-uefi/generic-aarch64/meta

@@ -0,0 +1,10 @@
+BOARD_ID=generic-aarch64
+BOARD_NAME="Generic aarch64"
+CHASSIS=embedded
+BOOTLOADER=grub
+KERNEL_FILE=Image
+BOOT_SYS=efi
+BOOT_SPL=false
+DISK_SIZE=6
+SUPERVISOR_MACHINE=qemuarm-64
+SUPERVISOR_ARCH=aarch64