configs/loongarch64_efi: new defconfig

Introduce bread new loongarch64-efi board, with skeleton
from aarch64-efi board.

It corverd most LoongArch64 systems.

Linux 6.12, as the most recent LTS kernel, was chosen
to ensure proper architecture support is included.

This board config is validated on my Lemote A2101
Loongson 3A5000 board.

A developer entry is created for myself for future contacts
as well.

Signed-off-by: Jiaxun Yang <jiaxun.yang@flygoat.com>
Reviewed-by: Romain Naour <romain.naour@smile.fr>
Signed-off-by: Julien Olivain <ju.o@free.fr>

DEVELOPERS

@@ -1644,6 +1644,8 @@ F:	package/rtty/
 
 N:	Jiaxun Yang <jiaxun.yang@flygoat.com>
 F:	arch/Config.in.loongarch
+F:	board/loongarch64-efi
+F:	configs/loongarch64_efi_defconfig
 
 N:	Joachim Wiberg <troglobit@gmail.com>
 F:	configs/globalscale_espressobin_defconfig

board/loongarch64-efi/genimage-efi.cfg

@@ -0,0 +1,30 @@
+image efi-part.vfat {
+	vfat {
+		file EFI {
+			image = "efi-part/EFI"
+		}
+		file vmlinux.efi {
+			image = "vmlinux.efi"
+		}
+	}
+
+	size = 64M
+}
+
+image disk.img {
+	hdimage {
+		partition-table-type = "gpt"
+	}
+
+	partition boot {
+		image = "efi-part.vfat"
+		partition-type-uuid = U
+		offset = 32K
+		bootable = true
+	}
+
+	partition root {
+		partition-type-uuid = root-loongarch64
+		image = "rootfs.ext2"
+	}
+}

board/loongarch64-efi/grub.cfg

@@ -0,0 +1,6 @@
+/set default="0"
+set timeout="5"
+
+menuentry "Buildroot" {
+	linux /vmlinux.efi root=PARTLABEL=root rootwait console=ttyS0,115200
+}

board/loongarch64-efi/patches/linux-headers/linux-headers.hash

@@ -0,0 +1 @@
+../linux/linux.hash

board/loongarch64-efi/patches/linux/linux.hash

@@ -0,0 +1,2 @@
+# From https://www.kernel.org/pub/linux/kernel/v6.x/sha256sums.asc
+sha256  a9b020721778384507010177d3929e7d4058f7f6120f05a99d56b5c5c0346a70  linux-6.12.32.tar.xz

board/loongarch64-efi/post-image.sh

@@ -0,0 +1,5 @@
+#!/bin/sh
+
+BOARD_DIR="$(dirname "$0")"
+
+cp -f "${BOARD_DIR}/grub.cfg" "${BINARIES_DIR}/efi-part/EFI/BOOT/grub.cfg"

board/loongarch64-efi/readme.txt

@@ -0,0 +1,38 @@
+The loongarch64_efi_defconfig allows to build a minimal Linux system that
+can boot on all loongarch64 systems providing an New World [1] EFI firmware.
+
+This includes almost all LoongArch Loongson-3 series workstations and servers,
+see [2] for hardware and firmware information.
+
+Building and booting
+====================
+
+$ make loongarch64_efi_defconfig
+$ make
+
+The file output/images/disk.img is a complete disk image that can be
+booted, it includes the grub2 bootloader, Linux kernel and root
+filesystem.
+
+Testing under Qemu
+==================
+
+This image can also be tested using Qemu:
+
+qemu-system-loongarch64 \
+	-M virt \
+	-cpu la464 \
+	-nographic \
+	-bios </path/to/QEMU_EFI.fd> \
+	-drive file=output/images/disk.img,if=none,format=raw,id=hd0 \
+	-device virtio-blk-pci,drive=hd0 \
+	-netdev user,id=eth0 \
+	-device virtio-net-pci,netdev=eth0
+
+Note that </path/to/QEMU_EFI.fd> needs to point to a valid loongarch64 UEFI
+firmware image for qemu.
+It may be provided by your distribution as a edk2-loongarch64 package,
+in path such as /usr/share/edk2/loongarch64/QEMU_EFI.fd .
+
+[1]: https://areweloongyet.com/en/docs/old-and-new-worlds/
+[2]: https://github.com/loongson/Firmware

configs/loongarch64_efi_defconfig

@@ -0,0 +1,22 @@
+BR2_loongarch64=y
+BR2_PACKAGE_HOST_LINUX_HEADERS_CUSTOM_6_12=y
+BR2_GLOBAL_PATCH_DIR="board/loongarch64-efi/patches"
+BR2_DOWNLOAD_FORCE_CHECK_HASHES=y
+BR2_ROOTFS_DEVICE_CREATION_DYNAMIC_EUDEV=y
+BR2_ROOTFS_POST_IMAGE_SCRIPT="board/loongarch64-efi/post-image.sh support/scripts/genimage.sh"
+BR2_ROOTFS_POST_SCRIPT_ARGS="-c board/loongarch64-efi/genimage-efi.cfg"
+BR2_LINUX_KERNEL=y
+BR2_LINUX_KERNEL_CUSTOM_VERSION=y
+BR2_LINUX_KERNEL_CUSTOM_VERSION_VALUE="6.12.32"
+BR2_LINUX_KERNEL_USE_ARCH_DEFAULT_CONFIG=y
+BR2_LINUX_KERNEL_NEEDS_HOST_OPENSSL=y
+BR2_LINUX_KERNEL_NEEDS_HOST_LIBELF=y
+BR2_TARGET_ROOTFS_EXT2=y
+BR2_TARGET_ROOTFS_EXT2_4=y
+BR2_TARGET_ROOTFS_EXT2_SIZE="200M"
+# BR2_TARGET_ROOTFS_TAR is not set
+BR2_TARGET_GRUB2=y
+BR2_TARGET_GRUB2_LOONGARCH64_EFI=y
+BR2_PACKAGE_HOST_DOSFSTOOLS=y
+BR2_PACKAGE_HOST_GENIMAGE=y
+BR2_PACKAGE_HOST_MTOOLS=y