board: add support for Hardkernel ODROID-C2 Board

The ODROID-C2 is a 64-bit quad-core single board computer(SBC) that is
one of the most cost-effective 64bit development boards available in the
ARM world.

http://www.hardkernel.com/main/products/prdt_info.php?g_code=G145457216438

[Peter: fix typos, drop neon/C++ settings, use git hash for Linux/U-Boot]
Signed-off-by: Brian Kim <brian.kim@hardkernel.com>
Signed-off-by: Peter Korsgaard <peter@korsgaard.com>

board/hardkernel/odroidc2/boot.ini

@@ -0,0 +1,22 @@
+ODROIDC2-UBOOT-CONFIG
+
+# HDMI mode
+setenv m "720p60hz" # Progressive 60Hz
+
+# HDMI BPP Mode
+setenv m_bpp "32"
+
+# Default Console Device Setting
+setenv condev "console=ttyS0,115200n8"	# Serial Console
+
+# Boot Arguments
+setenv bootargs "root=/dev/mmcblk0p2 rootwait ro ${condev} no_console_suspend hdmimode=${m} m_bpp=${m_bpp} vout=${vout} fsck.repair=yes net.ifnames=0 elevator=noop"
+
+# Load Images
+setenv loadaddr "0x11000000"
+setenv dtb_loadaddr "0x10000000"
+fatload mmc 0:1 ${loadaddr} Image
+fatload mmc 0:1 ${dtb_loadaddr} meson64_odroidc2.dtb
+
+# Booting
+booti ${loadaddr} - ${dtb_loadaddr}

board/hardkernel/odroidc2/genimage.cfg

@@ -0,0 +1,27 @@
+image boot.vfat {
+	vfat {
+		files = {
+			"boot.ini",
+			"Image",
+			"meson64_odroidc2.dtb"
+		}
+	}
+	size = 32M
+}
+
+image sdcard.img {
+	hdimage {
+	}
+
+	partition vfat {
+		partition-type = 0xC
+		image = "boot.vfat"
+		offset = 1048576
+	}
+
+	partition rootfs {
+		partition-type = 0x83
+		image = "rootfs.ext4"
+		size = 512M
+	}
+}

board/hardkernel/odroidc2/post-image.sh

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+#!/bin/sh
+
+BOARD_DIR="$(dirname $0)"
+GENIMAGE_CFG="${BOARD_DIR}/genimage.cfg"
+GENIMAGE_TMP="${BUILD_DIR}/genimage.tmp"
+
+cp ${BOARD_DIR}/boot.ini ${BINARIES_DIR}/
+
+rm -rf "${GENIMAGE_TMP}"
+
+genimage                           \
+	--rootpath "${TARGET_DIR}"     \
+	--tmppath "${GENIMAGE_TMP}"    \
+	--inputpath "${BINARIES_DIR}"  \
+	--outputpath "${BINARIES_DIR}" \
+	--config "${GENIMAGE_CFG}"
+
+dd if=${BINARIES_DIR}/u-boot.bin of=${BINARIES_DIR}/sdcard.img bs=1 count=442 conv=sync,notrunc
+dd if=${BINARIES_DIR}/u-boot.bin of=${BINARIES_DIR}/sdcard.img bs=512 skip=1 seek=1 conv=fsync,notrunc

board/hardkernel/odroidc2/readme.txt

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+ODROID-C2
+
+Intro
+=====
+To be able to use ODROID-C2 board with the images generated by
+Buildroot, you have to prepare the SDCard or eMMC.
+
+How to build it
+===============
+
+  $ make odroidc2_defconfig
+
+Then you can edit the build options using
+
+  $ make menuconfig
+
+Compile all and build rootfs image:
+
+  $ make
+
+Note: you will need to have access to the network, since Buildroot will
+download the packages' sources.
+
+Result of the build
+-------------------
+
+After building, you should obtain this tree:
+
+    output/images/
+    +-- Image
+    +-- boot.ini                   [1]
+    +-- boot.vfat
+    +-- meson64_odroidc2.dtb
+    +-- rootfs.ext2
+    +-- rootfs.ext4
+    +-- rootfs.tar
+    +-- sdcard.img
+    `-- u-boot.bin
+
+[1] This is the ODROID-C2 configuration file used in u-boot.
+
+How to write the SD card or eMMC
+================================
+
+Once the build process is finished you will have an image called "sdcard.img"
+in the output/images/ directory.
+
+Copy the bootable "sdcard.img" onto an SD card or eMMC with "dd":
+
+  $ sudo dd if=output/images/sdcard.img of=/dev/sdX
+
+Insert the SDcard into your ODROID-C2, and power it up. Your new system
+should come up now.

configs/odroidc2_defconfig

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+# Architecture
+BR2_aarch64=y
+
+# System
+BR2_TARGET_GENERIC_HOSTNAME="odroidc2"
+BR2_TARGET_ROOTFS_EXT2=y
+BR2_TARGET_ROOTFS_EXT2_4=y
+BR2_ROOTFS_POST_IMAGE_SCRIPT="board/hardkernel/odroidc2/post-image.sh"
+
+# Kernel
+BR2_KERNEL_HEADERS_VERSION=y
+BR2_DEFAULT_KERNEL_VERSION="3.14.29"
+BR2_PACKAGE_HOST_LINUX_HEADERS_CUSTOM_3_14=y
+BR2_LINUX_KERNEL=y
+BR2_LINUX_KERNEL_CUSTOM_GIT=y
+BR2_LINUX_KERNEL_CUSTOM_REPO_URL="https://github.com/hardkernel/linux.git"
+BR2_LINUX_KERNEL_CUSTOM_REPO_VERSION="db9b5cfbd380d2316b7723599ee0c7e9d866db17"
+BR2_LINUX_KERNEL_DEFCONFIG="odroidc2"
+BR2_LINUX_KERNEL_DTS_SUPPORT=y
+BR2_LINUX_KERNEL_BUILD_DEFAULT_DTS=y
+BR2_LINUX_KERNEL_USE_INTREE_DTS=y
+BR2_LINUX_KERNEL_INTREE_DTS_NAME="meson64_odroidc2"
+BR2_LINUX_KERNEL_IMAGE=y
+
+# U-Boot
+BR2_TARGET_UBOOT=y
+BR2_TARGET_UBOOT_CUSTOM_GIT=y
+BR2_TARGET_UBOOT_CUSTOM_REPO_URL="https://github.com/hardkernel/u-boot.git"
+BR2_TARGET_UBOOT_CUSTOM_REPO_VERSION="f416a769454b89c39d5b217d28bd3c9f5d1594df"
+BR2_TARGET_UBOOT_BOARDNAME="odroidc2"
+
+# Required tools to create the SD image
+BR2_PACKAGE_HOST_DOSFSTOOLS=y
+BR2_PACKAGE_HOST_GENIMAGE=y
+BR2_PACKAGE_HOST_MTOOLS=y