mtd: base-files: Unify dual-firmware devices (Linksys)

Consistently handle boot-count reset and upgrade across
ipq40xx, ipq806x, kirkwood, mvebu

Dual-firmware devices often utilize a specific MTD partition
to record the number of times the boot loader has initiated boot.

Most of these devices are NAND, typically with a 2k erase size.
When this code was ported to the ipq40xx platform, the device in hand
used NOR for this partition, with a 16-byte "record" size. As the
implementation of `mtd resetbc` is by-platform, the hard-coded nature
of this change prevented proper operation of a NAND-based device.

* Unified the "NOR" variant with the rest of the Linksys variants

* Added logging to indicate success and failure

* Provided a meaningful return value for scripting

* "Protected" the use of `mtd resetbc` in start-up scripts so that
   failure does not end the boot sequence

* Moved Linksys-specific actions into common `/etc/init.d/bootcount`

For upgrade, these devices need to determine which partition to flash,
as well as set certain U-Boot envirnment variables to change the next
boot to the newly flashed version.

* Moved upgrade-related environment changes out of bootcount

* Combined multiple flashes of environment into single one

* Current-partition detection now handles absence of `boot_part`

Runtime-tested: Linksys EA8300

Signed-off-by: Jeff Kletsky <git-commits@allycomm.com>
Signed-off-by: Christian Lamparter <chunkeey@gmail.com>
[checkpatch.pl fixes, traded split strings for 80+ chars per line]

target/linux/ipq40xx/base-files/etc/init.d/bootcount

@@ -10,5 +10,8 @@ start() {
 		[ -n "$(fw_printenv bootcount changed 2>/dev/null)" ] &&\
 			echo -e "bootcount\nchanged\n" | /usr/sbin/fw_setenv -s -
 		;;
+	linksys,ea6350v3)
+		mtd resetbc s_env || true
+		;;
 	esac
 }

target/linux/ipq40xx/base-files/etc/init.d/zlinksys_recovery

@@ -1,34 +0,0 @@
-#!/bin/sh /etc/rc.common
-#
-# This script sets auto_recovery to "yes" and resets the boot counter to 0.
-# As a golden rule, this should be the latest script to run at boot. For a
-# developer snapshot, it is fine to set auto_recovery here. But for a stable
-# release, this script must in fact turn off auto_recovery.
-#
-# Why? Because the custom sysupgrade script for the device will turn on
-# auto_recovery to "yes". And it's the job of this script to set the
-# boot boot_count to 0 and then disable auto_recovery, as that condition
-# means that the stable release went well.
-#
-# I have to repeat: this script should be changed for stable releases.
-
-START=99
-boot() {
-	. /lib/functions.sh
-
-	case $(board_name) in
-		linksys,ea6350v3)
-			# make sure auto_recovery in uboot is always on
-			IS_AUTO_RECOVERY="$(fw_printenv -n auto_recovery)"
-			if [ "$IS_AUTO_RECOVERY" != "yes" ] ; then
-				fw_setenv auto_recovery yes
-				echo "Linksys EA6350v3: fw_setenv: auto_recovery has been set to yes"
-			fi
-			# reset the boot counter
-			fw_setenv boot_count 0
-			mtd resetbc s_env
-			echo "Linksys EA6350v3: boot counter has been reset"
-			echo "Linksys EA6350v3: boot_part=$(fw_printenv -n boot_part)"
-			;;
-	esac
-}

target/linux/ipq40xx/base-files/lib/upgrade/linksys.sh

@@ -1,26 +1,51 @@
 linksys_get_target_firmware() {
+
+	local cur_boot_part mtd_ubi0
+
 	cur_boot_part=$(/usr/sbin/fw_printenv -n boot_part)
-	target_firmware=""
-	if [ "$cur_boot_part" = "1" ]; then
-		# current primary boot - update alt boot
-		target_firmware="alt_kernel"
-		fw_setenv boot_part 2
-		# In the Linksys EA6350v3, it is enough to set the boot_part as the boot command line is
-		# bootcmd=if test $boot_part = 1; then run bootpart1; else run bootpart2; fi
-		# - You probably want to use that if your device's uboot does not eval bootcmd
-		#fw_setenv bootcmd "run altnandboot"
-	elif [ "$cur_boot_part" = "2" ]; then
-		# current alt boot - update primary boot
-		target_firmware="kernel"
-		fw_setenv boot_part 1
-		#fw_setenv bootcmd "run nandboot"
+	if [ -z "${cur_boot_part}" ] ; then
+		mtd_ubi0=$(cat /sys/devices/virtual/ubi/ubi0/mtd_num)
+		case $(egrep "^mtd${mtd_ubi0}:" /proc/mtd | cut -d '"' -f 2) in
+		kernel|rootfs)
+			cur_boot_part=1
+			;;
+		alt_kernel|alt_rootfs)
+			cur_boot_part=2
+			;;
+		esac
+		>&2 printf "Current boot_part='%s' selected from ubi0/mtd_num='%s'" \
+			"${cur_boot_part}" "${mtd_ubi0}"
 	fi
 
-	# re-enable recovery so we get back if the new firmware is broken
-	fw_setenv auto_recovery yes
-	# see /etc/init.d/zlinksys_recovery
+	# OEM U-Boot for EA6350v3 and EA8300; bootcmd=
+	#  if test $auto_recovery = no;
+	#      then bootipq;
+	#  elif test $boot_part = 1;
+	#      then run bootpart1;
+	#      else run bootpart2;
+	#  fi
 
-	echo "$target_firmware"
+	case $cur_boot_part in
+	1)
+		fw_setenv -s - <<-EOF
+			boot_part 2
+			auto_recovery yes
+		EOF
+		printf "alt_kernel"
+		return
+		;;
+	2)
+		fw_setenv -s - <<-EOF
+			boot_part 1
+			auto_recovery yes
+		EOF
+		printf "kernel"
+		return
+		;;
+	*)
+		return
+		;;
+	esac
 }
 
 linksys_get_root_magic() {