qualcommax: ipq50xx: functions for bootconfig partition

The BOOTCONFIG partition is used by Qualcomm's boot chain to store
metadata about the device's startup configuration. It contains info such
as versioning, configuration flags, primary boot partition, and more.

Newer devices with dual boot partitions not only store the active boot
partition in a U-boot variable but also in partition info in the
BOOTCONFIG partition. As such, add library functions to set and toggle
the active boot partition.

Signed-off-by: George Moussalem <[email protected]>
Link: https://github.com/openwrt/openwrt/pull/21038
Signed-off-by: Robert Marko <[email protected]>

target/linux/qualcommax/ipq50xx/base-files/lib/functions/bootconfig.sh

@@ -0,0 +1,177 @@
+. /lib/functions.sh
+
+PART_SIZE=20
+NAME_SIZE=16
+MAX_NUM_PARTS=16
+
+MAGIC_START_HEX="a0 a1 a2 a3"
+MAGIC_START_TRY_HEX="a1 a1 a2 a3"
+MAGIC_END_HEX="b0 b1 b2 b3"
+
+validate_bootconfig_magic() {
+	local file=$1
+	magic_start=$(hexdump -v -n 4 -e '4/1 "%02x "' "$file")
+	magic_end=$(hexdump -v -s 332 -n 4 -e '4/1 "%02x "' "$file")
+	
+	if [ "$magic_start" != "$MAGIC_START_HEX" ] && \
+	   [ "$magic_start" != "$MAGIC_START_TRY_HEX" ]; then
+		echo "Not a valid bootconfig file, start magic does not match" >&2
+		return 1
+	fi
+
+	if [ "$magic_end" != "$MAGIC_END_HEX" ]; then
+		echo "Not a valid bootconfig file, end magic does not match" >&2
+		return 1
+	fi
+	return 0
+}
+
+get_bootconfig_numparts() {
+	local file=$1
+	numpartshex=$(hexdump -v -s 8 -n 4 -e '4/1 "%02x "' "$file")
+	numparts=$(( 0x$(echo $numpartshex | awk '{print $4$3$2$1}') ))
+	echo ${numparts}
+}
+
+get_bootconfig_partidx() {
+	local file=$1
+	local partname=$2
+	local numparts=$(get_bootconfig_numparts "$file")
+
+	if [ -z "$numparts" ]; then
+		echo "Could not get number of partitions" >&2
+		return
+	fi
+
+	if [ $numparts -gt $MAX_NUM_PARTS ]; then
+		numparts=$MAX_NUM_PARTS
+	fi
+
+	for i in $(seq 0 $((numparts -1))); do
+		nameoffset=$((12 + i * $PART_SIZE))
+		nameraw=$(dd if="$file" bs=1 skip="$nameoffset" count=12 2>/dev/null)
+		name=${nameraw//S'\x00'/}
+		if [ "$partname" = "$name" ]; then
+			echo $i
+		fi
+	done
+}
+
+get_bootconfig_primaryboot() {
+	local file=$1
+	local partname=$2
+
+	local partidx=$(get_bootconfig_partidx "$file" "$partname")
+	if ! echo "$partidx" | grep -Eq '^[0-9]+$'; then
+		echo "Could not get partition index for $partname in $file" >&2
+		return
+	fi
+
+	if [ "$partidx" -ge 0 ] && [ "$partidx" -lt $MAX_NUM_PARTS ]; then
+		offset=$((12 + $partidx * $PART_SIZE + $NAME_SIZE))
+		primaryboothex=$(hexdump -v -s "$offset" -n 4 -e '4/1 "%02x "' $file)
+		primaryboot=$(( 0x$(echo $primaryboothex | awk '{print $4$3$2$1}') ))
+		echo $primaryboot
+	fi
+}
+
+_set_bootconfig_primaryboot() {
+	local file=$1
+	local partname=$2
+	local primaryboot=$3
+	local primaryboothex
+	local partidx
+	local primarybootoffset
+
+	partidx=$(get_bootconfig_partidx "$file" "$partname")
+	if ! echo "$partidx" | grep -Eq '^[0-9]+$'; then
+		echo "Could not get partition index for $2" >&2
+		return 1
+	fi
+	primarybootoffset=$((12 + $partidx * $PART_SIZE + $NAME_SIZE))
+
+	case "$primaryboot" in
+		0)
+			printf "\x00\x00\x00\x00" | dd of="$file" seek="$primarybootoffset" bs=1 count=4 conv=notrunc 2>/dev/null
+			;;
+		1)
+			printf "\x01\x00\x00\x00" | dd of="$file" seek="$primarybootoffset" bs=1 count=4 conv=notrunc 2>/dev/null
+			;;
+		*)
+			echo "invalid argument: primaryboot must be 0 or 1" >&2
+			return 1
+			;;
+	esac
+}
+
+set_bootconfig_primaryboot() {
+	local file=$1
+	local partname=$2
+	local primaryboot=$3
+
+	[ -z "$file" ] || [ -z "$partname" ] || [ -z "$primaryboot" ] && {
+		echo "usage: $0 <file> <partition name> <0|1>"
+		return 1
+	}
+
+	[ ! -e "$file" ] && {
+		echo "file $file not found" >&2
+		return 1
+	}
+
+	[ ! -w $file ] && {
+		echo "file $file not writable" >&2
+		return 1
+	}
+
+	validate_bootconfig_magic "$file"
+	[ $? -ne 0 ] && return 1
+
+	_set_bootconfig_primaryboot $file $partname $primaryboot
+	[ $? -ne 0 ] && return 1
+
+	return 0
+}
+
+toggle_bootconfig_primaryboot() {
+	local file=$1
+	local partname=$2
+	local primaryboot
+	
+	[ -z "$file" ] || [ -z "$partname" ] && {
+		echo "usage: $0 <file> <partition name>"
+		return 1
+	}
+
+	[ ! -e "$file" ] && {
+		echo "file $file not found" >&2
+		return 1
+	}
+
+	[ ! -w $file ] && {
+		echo "file $file not writable" >&2
+		return 1
+	}
+
+	validate_bootconfig_magic "$file"
+	[ $? -ne 0 ] && return 1
+	
+	primaryboot=$(get_bootconfig_primaryboot "$1" "$2")
+
+	case "$primaryboot" in
+		0)
+			_set_bootconfig_primaryboot "$1" "$2" 1
+			;;
+		1)
+			_set_bootconfig_primaryboot "$1" "$2" 0
+			;;
+		*)
+			echo "invalid value: primaryboot must be 0 or 1" >&2
+			return 1
+			;;
+	esac
+
+	[ $? -ne 0 ] && return 1
+
+	return 0
+}