#!/bin/sh
#
# Licensed under the terms of the GNU GPL License version 2 or later.
#
# Author: Peter Tyser <ptyser@xes-inc.com>
#
# U-Boot firmware supports the booting of images in the Flattened Image
# Tree (FIT) format.  The FIT format uses a device tree structure to
# describe a kernel image, device tree blob, ramdisk, etc.  This script
# creates an Image Tree Source (.its file) which can be passed to the
# 'mkimage' utility to generate an Image Tree Blob (.itb file).  The .itb
# file can then be booted by U-Boot (or other bootloaders which support
# FIT images).  See doc/uImage.FIT/howto.txt in U-Boot source code for
# additional information on FIT images.
#

usage() {
	printf "Usage: %s -A arch -C comp -a addr -e entry" "$(basename "$0")"
	printf " -v version -k kernel [-D name -n address -d dtb] -o its_file"

	printf "\n\t-A ==> set architecture to 'arch'"
	printf "\n\t-C ==> set compression type 'comp'"
	printf "\n\t-c ==> set config name 'config'"
	printf "\n\t-a ==> set load address to 'addr' (hex)"
	printf "\n\t-e ==> set entry point to 'entry' (hex)"
	printf "\n\t-f ==> set device tree compatible string"
	printf "\n\t-i ==> include initrd Blob 'initrd'"
	printf "\n\t-v ==> set kernel version to 'version'"
	printf "\n\t-k ==> include kernel image 'kernel'"
	printf "\n\t-D ==> human friendly Device Tree Blob 'name'"
	printf "\n\t-n ==> fdt unit-address 'address'"
	printf "\n\t-d ==> include Device Tree Blob 'dtb'"
	printf "\n\t-r ==> include RootFS blob 'rootfs'"
	printf "\n\t-H ==> specify hash algo instead of SHA1"
	printf "\n\t-o ==> create output file 'its_file'"
	printf "\n\t-O ==> create config with dt overlay 'name:dtb'"
	printf "\n\t\t(can be specified more than once)\n"
	exit 1
}

FDTNUM=1
ROOTFSNUM=1
INITRDNUM=1
HASH=sha1
LOADABLES=
DTOVERLAY=
DTADDR=

while getopts ":A:a:c:C:D:d:e:f:i:k:n:o:O:v:r:H:" OPTION
do
	case $OPTION in
		A ) ARCH=$OPTARG;;
		a ) LOAD_ADDR=$OPTARG;;
		c ) CONFIG=$OPTARG;;
		C ) COMPRESS=$OPTARG;;
		D ) DEVICE=$OPTARG;;
		d ) DTB=$OPTARG;;
		e ) ENTRY_ADDR=$OPTARG;;
		f ) COMPATIBLE=$OPTARG;;
		i ) INITRD=$OPTARG;;
		k ) KERNEL=$OPTARG;;
		n ) FDTNUM=$OPTARG;;
		o ) OUTPUT=$OPTARG;;
		O ) DTOVERLAY="$DTOVERLAY ${OPTARG}";;
		r ) ROOTFS=$OPTARG;;
		H ) HASH=$OPTARG;;
		v ) VERSION=$OPTARG;;
		* ) echo "Invalid option passed to '$0' (options:$*)"
		usage;;
	esac
done

# Make sure user entered all required parameters
if [ -z "${ARCH}" ] || [ -z "${COMPRESS}" ] || [ -z "${LOAD_ADDR}" ] || \
	[ -z "${ENTRY_ADDR}" ] || [ -z "${VERSION}" ] || [ -z "${KERNEL}" ] || \
	[ -z "${OUTPUT}" ] || [ -z "${CONFIG}" ]; then
	usage
fi

ARCH_UPPER=$(echo "$ARCH" | tr '[:lower:]' '[:upper:]')

if [ -n "${COMPATIBLE}" ]; then
	COMPATIBLE_PROP="compatible = \"${COMPATIBLE}\";"
fi

[ "$DTOVERLAY" ] && {
	dtbsize=$(wc -c "$DTB" | cut -d' ' -f1)
	DTADDR=$(printf "0x%08x" $(($LOAD_ADDR - $dtbsize)) )
}

# Conditionally create fdt information
if [ -n "${DTB}" ]; then
	FDT_NODE="
		fdt-$FDTNUM {
			description = \"${ARCH_UPPER} OpenWrt ${DEVICE} device tree blob\";
			${COMPATIBLE_PROP}
			data = /incbin/(\"${DTB}\");
			type = \"flat_dt\";
			${DTADDR:+load = <${DTADDR}>;}
			arch = \"${ARCH}\";
			compression = \"none\";
			hash@1 {
				algo = \"crc32\";
			};
			hash@2 {
				algo = \"${HASH}\";
			};
		};
"
	FDT_PROP="fdt = \"fdt-$FDTNUM\";"
fi

if [ -n "${INITRD}" ]; then
	INITRD_NODE="
		initrd-$INITRDNUM {
			description = \"${ARCH_UPPER} OpenWrt ${DEVICE} initrd\";
			${COMPATIBLE_PROP}
			data = /incbin/(\"${INITRD}\");
			type = \"ramdisk\";
			arch = \"${ARCH}\";
			os = \"linux\";
			hash@1 {
				algo = \"crc32\";
			};
			hash@2 {
				algo = \"${HASH}\";
			};
		};
"
	INITRD_PROP="ramdisk=\"initrd-${INITRDNUM}\";"
fi


if [ -n "${ROOTFS}" ]; then
	dd if="${ROOTFS}" of="${ROOTFS}.pagesync" bs=4096 conv=sync
	ROOTFS_NODE="
		rootfs-$ROOTFSNUM {
			description = \"${ARCH_UPPER} OpenWrt ${DEVICE} rootfs\";
			${COMPATIBLE_PROP}
			data = /incbin/(\"${ROOTFS}.pagesync\");
			type = \"filesystem\";
			arch = \"${ARCH}\";
			compression = \"none\";
			hash@1 {
				algo = \"crc32\";
			};
			hash@2 {
				algo = \"${HASH}\";
			};
		};
"
	LOADABLES="${LOADABLES:+$LOADABLES, }\"rootfs-${ROOTFSNUM}\""
fi

# add DT overlay blobs
FDTOVERLAY_NODE=""
OVCONFIGS=""
[ "$DTOVERLAY" ] && for overlay in $DTOVERLAY ; do
	overlay_blob=${overlay##*:}
	ovname=${overlay%%:*}
	ovnode="fdt-$ovname"
	ovsize=$(wc -c "$overlay_blob" | cut -d' ' -f1)
	echo "$ovname ($overlay_blob) : $ovsize" >&2
	DTADDR=$(printf "0x%08x" $(($DTADDR - $ovsize)))
	FDTOVERLAY_NODE="$FDTOVERLAY_NODE

		$ovnode {
			description = \"${ARCH_UPPER} OpenWrt ${DEVICE} device tree overlay $ovname\";
			${COMPATIBLE_PROP}
			data = /incbin/(\"${overlay_blob}\");
			type = \"flat_dt\";
			arch = \"${ARCH}\";
			load = <${DTADDR}>;
			compression = \"none\";
			hash@1 {
				algo = \"crc32\";
			};
			hash@2 {
				algo = \"${HASH}\";
			};
		};
"
	OVCONFIGS="$OVCONFIGS

		config-$ovname {
			description = \"OpenWrt ${DEVICE} with $ovname\";
			kernel = \"kernel-1\";
			fdt = \"fdt-$FDTNUM\", \"$ovnode\";
			${LOADABLES:+loadables = ${LOADABLES};}
			${COMPATIBLE_PROP}
			${INITRD_PROP}
		};
	"
done

# Create a default, fully populated DTS file
DATA="/dts-v1/;

/ {
	description = \"${ARCH_UPPER} OpenWrt FIT (Flattened Image Tree)\";
	#address-cells = <1>;

	images {
		kernel-1 {
			description = \"${ARCH_UPPER} OpenWrt Linux-${VERSION}\";
			data = /incbin/(\"${KERNEL}\");
			type = \"kernel\";
			arch = \"${ARCH}\";
			os = \"linux\";
			compression = \"${COMPRESS}\";
			load = <${LOAD_ADDR}>;
			entry = <${ENTRY_ADDR}>;
			hash@1 {
				algo = \"crc32\";
			};
			hash@2 {
				algo = \"$HASH\";
			};
		};
${INITRD_NODE}
${FDT_NODE}
${FDTOVERLAY_NODE}
${ROOTFS_NODE}
	};

	configurations {
		default = \"${CONFIG}\";
		${CONFIG} {
			description = \"OpenWrt ${DEVICE}\";
			kernel = \"kernel-1\";
			${FDT_PROP}
			${LOADABLES:+loadables = ${LOADABLES};}
			${COMPATIBLE_PROP}
			${INITRD_PROP}
		};
		${OVCONFIGS}
	};
};"

# Write .its file to disk
echo "$DATA" > "${OUTPUT}"