configs/nanopi_m4: new defconfig

A defconfig for the friendlyarm nanopi-m4 was added in
493c3979a4, but then removed
in a24bd8936f because an ARM32
compiler was needed to build ATF, and this was not supported
back then.

Now, since package/arm-gnu-a-toolchain/ has been added, this
defconfig can be re-introduced.

Following new changes are introduced in comparision with the
older changeset:
        - readme updated
        - GPT partition layout
        - update defconfig to build ATF
        - bump u-boot to 2020.07
        - bump linux to 5.8.2

Signed-off-by: Suniel Mahesh <sunil@amarulasolutions.com>
Reviewed-by: Jagan Teki <jagan@amarulasolutions.com>
Signed-off-by: Arnout Vandecappelle (Essensium/Mind) <arnout@mind.be>
[Arnout: fixate U-Boot version; remove blind BR2_TARGET_UBOOT_NEEDS_PYTHON]

DEVELOPERS

@@ -2451,11 +2451,13 @@ F:	package/powertop/
 
 N:	Suniel Mahesh <sunil@amarulasolutions.com>
 F:	board/firefly/
+F:	board/friendlyarm/nanopi-m4
 F:	board/orangepi/orangepi-rk3399
 F:	board/pine64/rockpro64
 F:	board/radxa/rockpi-4
 F:	board/radxa/rockpi-n8
 F:	board/radxa/rockpi-n10
+F: 	configs/nanopi_m4_defconfig
 F:	configs/orangepi_rk3399_defconfig
 F:	configs/roc_pc_rk3399_defconfig
 F:	configs/rock_pi_4_defconfig

board/friendlyarm/nanopi-m4/extlinux.conf

@@ -0,0 +1,4 @@
+label RK3399_NANOPI_M4 linux
+  kernel /Image
+  devicetree /rk3399-nanopi-m4.dtb
+  append earlycon=uart8250,mmio32,0xff1a0000 root=/dev/mmcblk1p4 rw rootwait

board/friendlyarm/nanopi-m4/genimage.cfg

@@ -0,0 +1,39 @@
+image boot.vfat {
+	vfat {
+		files = {
+			"Image",
+			"rk3399-nanopi-m4.dtb",
+			"extlinux"
+		}
+	}
+	size = 64M
+}
+
+image sdcard.img {
+
+	hdimage {
+		gpt = true
+	}
+
+	partition loader1 {
+		image = "idbloader.img"
+		offset = 32K
+	}
+
+	partition loader2 {
+		image = "u-boot.itb"
+		offset = 8M
+	}
+
+	partition boot {
+		partition-type = 0xC
+		bootable = "true"
+		image = "boot.vfat"
+		offset = 16M
+	}
+
+	partition rootfs {
+		partition-type = 0x83
+		image = "rootfs.ext4"
+	}
+}

board/friendlyarm/nanopi-m4/post-build.sh

@@ -0,0 +1,5 @@
+#!/bin/sh
+
+BOARD_DIR="$(dirname $0)"
+
+install -m 0644 -D $BOARD_DIR/extlinux.conf $BINARIES_DIR/extlinux/extlinux.conf

board/friendlyarm/nanopi-m4/readme.txt

@@ -0,0 +1,45 @@
+FriendlyARM NANOPI-M4
+=====================
+
+Build:
+
+  $ make nanopi_m4_defconfig
+  $ make
+
+Files created in output directory
+=================================
+
+output/images
+
+├── bl31.elf
+├── boot.vfat
+├── extlinux
+├── idbloader.img
+├── Image
+├── rk3399-nanopi-m4.dtb
+├── rootfs.ext2
+├── rootfs.ext4 -> rootfs.ext2
+├── rootfs.tar
+├── sdcard.img
+├── u-boot.bin
+└── u-boot.itb
+
+Creating bootable SD card:
+==========================
+
+Simply invoke (as root)
+
+sudo dd if=output/images/sdcard.img of=/dev/sdX && sync
+
+Where X is your SD card device
+
+Serial console
+--------------
+
+Baudrate for this board is 1500000
+
+Login:
+------
+Enter 'root' as login user, and the prompt is ready.
+
+https://wiki.amarulasolutions.com/bsp/rockchip/rk3399/nanopi_m4.html

configs/nanopi_m4_defconfig

@@ -0,0 +1,53 @@
+# Architecture
+BR2_aarch64=y
+BR2_cortex_a72_a53=y
+
+# Linux headers same as kernel, a 5.8 series
+BR2_PACKAGE_HOST_LINUX_HEADERS_CUSTOM_5_8=y
+
+# Firmware
+BR2_TARGET_ARM_TRUSTED_FIRMWARE=y
+BR2_TARGET_ARM_TRUSTED_FIRMWARE_CUSTOM_GIT=y
+BR2_TARGET_ARM_TRUSTED_FIRMWARE_CUSTOM_REPO_URL="https://git.trustedfirmware.org/TF-A/trusted-firmware-a.git"
+BR2_TARGET_ARM_TRUSTED_FIRMWARE_CUSTOM_REPO_VERSION="11a0a46a899fcc3b1fdb214b382f3d7495d88eca"
+BR2_TARGET_ARM_TRUSTED_FIRMWARE_PLATFORM="rk3399"
+BR2_TARGET_ARM_TRUSTED_FIRMWARE_BL31=y
+BR2_TARGET_ARM_TRUSTED_FIRMWARE_NEEDS_ARM32_TOOLCHAIN=y
+BR2_TARGET_ARM_TRUSTED_FIRMWARE_IMAGES=""
+
+# Bootloader
+BR2_TARGET_UBOOT=y
+BR2_TARGET_UBOOT_BUILD_SYSTEM_KCONFIG=y
+BR2_TARGET_UBOOT_CUSTOM_VERSION=y
+BR2_TARGET_UBOOT_CUSTOM_VERSION_VALUE="2020.07"
+BR2_TARGET_UBOOT_BOARD_DEFCONFIG="nanopi-m4-rk3399"
+BR2_TARGET_UBOOT_NEEDS_DTC=y
+BR2_TARGET_UBOOT_NEEDS_PYTHON3=y
+BR2_TARGET_UBOOT_NEEDS_ATF_BL31=y
+BR2_TARGET_UBOOT_NEEDS_ATF_BL31_ELF=y
+BR2_TARGET_UBOOT_FORMAT_CUSTOM=y
+BR2_TARGET_UBOOT_FORMAT_CUSTOM_NAME="u-boot.itb"
+BR2_TARGET_UBOOT_SPL=y
+BR2_TARGET_UBOOT_SPL_NAME="idbloader.img"
+
+# Kernel
+BR2_LINUX_KERNEL=y
+BR2_LINUX_KERNEL_CUSTOM_VERSION=y
+BR2_LINUX_KERNEL_CUSTOM_VERSION_VALUE="5.8.2"
+BR2_LINUX_KERNEL_USE_ARCH_DEFAULT_CONFIG=y
+BR2_LINUX_KERNEL_DTS_SUPPORT=y
+BR2_LINUX_KERNEL_INTREE_DTS_NAME="rockchip/rk3399-nanopi-m4"
+BR2_LINUX_KERNEL_NEEDS_HOST_OPENSSL=y
+
+# Filesystem
+BR2_TARGET_GENERIC_HOSTNAME="nanopi-m4"
+BR2_TARGET_GENERIC_ISSUE="Welcome to NANOPI-M4"
+BR2_TARGET_ROOTFS_EXT2=y
+BR2_TARGET_ROOTFS_EXT2_4=y
+BR2_PACKAGE_HOST_DOSFSTOOLS=y
+BR2_PACKAGE_HOST_GENIMAGE=y
+BR2_PACKAGE_HOST_MTOOLS=y
+BR2_PACKAGE_HOST_UBOOT_TOOLS=y
+BR2_ROOTFS_POST_IMAGE_SCRIPT="support/scripts/genimage.sh"
+BR2_ROOTFS_POST_SCRIPT_ARGS="-c board/friendlyarm/nanopi-m4/genimage.cfg"
+BR2_ROOTFS_POST_BUILD_SCRIPT="board/friendlyarm/nanopi-m4/post-build.sh"