From 7043e4334f0e751143b128dd695dc196d044fc1f Mon Sep 17 00:00:00 2001
From: Daniel Golle <daniel@makrotopia.org>
Date: Wed, 31 Mar 2021 14:19:16 +0100
Subject: [PATCH] mediatek: mt7622: improve sysupgrade on MMC

Use generic functions to acquire rootdev.
Make sure to wipe rootfs_data in case of '-n'.

Signed-off-by: Daniel Golle <daniel@makrotopia.org>
---
 .../mt7622/base-files/lib/upgrade/platform.sh | 61 ++++---------------
 1 file changed, 12 insertions(+), 49 deletions(-)

diff --git a/target/linux/mediatek/mt7622/base-files/lib/upgrade/platform.sh b/target/linux/mediatek/mt7622/base-files/lib/upgrade/platform.sh
index 97a492c7fb8..2c1460650fc 100755
--- a/target/linux/mediatek/mt7622/base-files/lib/upgrade/platform.sh
+++ b/target/linux/mediatek/mt7622/base-files/lib/upgrade/platform.sh
@@ -2,59 +2,24 @@ REQUIRE_IMAGE_METADATA=1
 RAMFS_COPY_BIN='fw_printenv fw_setenv blockdev'
 RAMFS_COPY_DATA='/etc/fw_env.config /var/lock/fw_printenv.lock'
 
-get_cmdline_var() {
-	local var=$1
-	local cmdlinevar tmp
-	local cmdline="$(cat /proc/cmdline)"
-
-	for cmdlinevar in $cmdline; do
-		tmp=${cmdlinevar##${var}}
-		[ "=" = "${tmp:0:1}" ] && echo ${tmp:1}
-	done
-}
-
-get_rootdev() {
-	local rootvol rootdev
-	rootvol=$(get_cmdline_var root)
-	rootvol=$(basename $rootvol)
-	[ -e /sys/class/block/$rootvol ] || {
-		rootvol=${rootvol%%[0-9]}
-		[ -e /sys/class/block/$rootvol ] && echo $rootvol
-		rootvol=${rootvol%%p}
-		[ -e /sys/class/block/$rootvol ] && echo $rootvol
-		return
-	}
-	[ -e /sys/class/block/$rootvol/partition ] || {
-		echo $rootvol
-		return
-	}
-	rootdev=$(busybox readlink -f /sys/class/block/$rootvol)
-	rootdev=$(basename ${rootdev%%/${rootvol}})
-	[ -e /sys/class/block/$rootdev ] && echo $rootdev
-}
-
-get_partition() {
-	for partname in /sys/class/block/$1/*/name; do
-		[ "$(cat ${partname})" = "$2" ] && {
-			basename ${partname%%/name}
-			break
-		}
-	done
-}
-
 platform_do_upgrade() {
 	local board=$(board_name)
 	local file_type=$(identify $1)
 
 	case "$board" in
 	bananapi,bpi-r64)
-		local rootdev=$(get_rootdev)
-		local fitpart=$(get_partition $rootdev production)
-		[ "$fitpart" ] || exit 1
+		export_bootdevice
+		export_partdevice rootdev 0
+		local fitpart=$(get_partition_by_name $rootdev "production")
+		[ "$fitpart" ] || return 1
 		dd if=/dev/zero of=/dev/$fitpart bs=4096 count=1 2>/dev/null
 		blockdev --rereadpt /dev/$rootdev
 		get_image "$1" | dd of=/dev/$fitpart
-		echo $rootdev > /tmp/sysupgrade.rootdev
+		blockdev --rereadpt /dev/$rootdev
+		local datapart=$(get_partition_by_name $rootdev "rootfs_data")
+		[ "$datapart" ] || return 0
+		dd if=/dev/zero of=/dev/$datapart bs=4096 count=1 2>/dev/null
+		echo $datapart > /tmp/sysupgrade.datapart
 		;;
 	buffalo,wsr-2533dhp2)
 		local magic="$(get_magic_long "$1")"
@@ -113,11 +78,9 @@ platform_check_image() {
 
 platform_copy_config_mmc() {
 	[ -e "$UPGRADE_BACKUP" ] || return
-	local rootdev=$(cat /tmp/sysupgrade.rootdev)
-	blockdev --rereadpt /dev/$rootdev
-	local datadev=$(get_partition $rootdev rootfs_data)
-	[ "$datadev" ] || echo "no rootfs_data partition, cannot keep configuration." >&2
-	dd if="$UPGRADE_BACKUP" of=/dev/$datadev
+	local datapart=$(cat /tmp/sysupgrade.datapart)
+	[ "$datapart" ] || echo "no rootfs_data partition, cannot keep configuration." >&2
+	dd if="$UPGRADE_BACKUP" of=/dev/$datapart
 	sync
 }