apm821xx: add support for the Cisco Meraki MR24

This patch adds support for the Cisco Meraki MR24 Access point
to the apm821xx target.

Board:		MR24 - Meraki MR24 Cloud Managed Access Point
CPU:		APM82181 SoC 800 MHz (PLB=200 OPB=100 EBC=100)
Flash size:	32MiB
RAM Size:	128MiB
Wireless:	Atheros AR9380 5.0GHz + Atheros AR9380 2.4GHz
Ethernet ports:	1x Gigabit Atheros AR8035

WARNING: The serial port needs a TTL/RS-232 v3.3 level converter!

For flashing instructions, visit:
<https://github.com/riptidewave93/Openwrt-MR24/blob/master/README.md#flashing>

Signed-off-by: Chris Blake <chrisrblake93@gmail.com>

target/linux/apm821xx/base-files/lib/upgrade/merakinand.sh

@@ -0,0 +1,65 @@
+#!/bin/sh
+#
+# Copyright (C) 2016 Chris Blake <chrisrblake93@gmail.com>
+#
+# Custom upgrade script for Meraki NAND devices (ex. MR24)
+# Based on merakinand.sh from the ar71xx target
+#
+. /lib/apm821xx.sh
+. /lib/functions.sh
+
+merakinand_do_kernel_check() {
+	local board_name="$1"
+	local tar_file="$2"
+	local image_magic_word=`(tar xf $tar_file sysupgrade-$board_name/kernel -O 2>/dev/null | dd bs=1 count=4 skip=0 2>/dev/null | hexdump -v -n 4 -e '1/1 "%02x"')`
+
+	# What is our kernel magic string?
+	case "$board_name" in
+	"mr24")
+		[ "$image_magic_word" == "8e73ed8a" ] && {
+			echo "pass" && return 0
+		}
+		;;
+	esac
+
+	exit 1
+}
+
+merakinand_do_platform_check() {
+	local board_name="$1"
+	local tar_file="$2"
+	local control_length=`(tar xf $tar_file sysupgrade-$board_name/CONTROL -O | wc -c) 2> /dev/null`
+	local file_type="$(identify_tar $2 sysupgrade-$board_name/root)"
+	local kernel_magic="$(merakinand_do_kernel_check $1 $2)"
+
+	case "$board_name" in
+	"mr24")
+		[ "$control_length" = 0 -o "$file_type" != "squashfs" -o "$kernel_magic" != "pass" ] && {
+			echo "Invalid sysupgrade file for $board_name"
+			return 1
+		}
+		;;
+	*)
+		echo "Unsupported device $board_name";
+		return 1
+		;;
+	esac
+
+	return 0
+}
+
+merakinand_do_upgrade() {
+	local tar_file="$1"
+	local board_name="$(cat /tmp/sysinfo/board_name)"
+
+	# Do we need to do any platform tweaks?
+	case "$board_name" in
+	"mr24")
+		nand_do_upgrade $1
+		;;
+	*)
+		echo "Unsupported device $board_name";
+		exit 1
+		;;
+	esac
+}

target/linux/apm821xx/base-files/lib/upgrade/platform.sh

@@ -11,6 +11,11 @@ platform_check_image() {
 	[ "$#" -gt 1 ] && return 1
 
 	case "$board" in
+	mr24)
+		merakinand_do_platform_check $board "$1"
+		return $?;
+		;;
+
 	*)
 		;;
 	esac
@@ -23,6 +28,10 @@ platform_pre_upgrade() {
 	local board=$(apm821xx_board_name)
 
 	case "$board" in
+	mr24)
+		merakinand_do_upgrade "$1"
+		;;
+
 	*)
 		;;
 	esac