[source] ar71xx: add revision detection for D-Link DIR-505 A1/A2

[LEDE Commits]

neoraider pushed a commit to source.git, branch master:
https://git.lede-project.org/?p=source.git;a=commitdiff;h=500a67a167a256002f8ab05171f49dfb86b03260

commit 500a67a167a256002f8ab05171f49dfb86b03260
Author: Matthias Schiffer <mschiffer at universe-factory.net>
AuthorDate: Thu Jul 28 15:43:25 2016 +0200

    ar71xx: add revision detection for D-Link DIR-505 A1/A2
    
    The A1 image also works on the A2, correctly set AR71XX_MODEL in this case.
    
    Signed-off-by: Matthias Schiffer <mschiffer at universe-factory.net>
---
 target/linux/ar71xx/base-files/lib/ar71xx.sh | 10 ++++++++++
 1 file changed, 10 insertions(+)

diff --git a/target/linux/ar71xx/base-files/lib/ar71xx.sh b/target/linux/ar71xx/base-files/lib/ar71xx.sh
index 56b5947..5d38555 100755
--- a/target/linux/ar71xx/base-files/lib/ar71xx.sh
+++ b/target/linux/ar71xx/base-files/lib/ar71xx.sh
@@ -73,6 +73,15 @@ cybertan_get_hw_magic() {
 	dd bs=8 count=1 skip=0 if=$part 2>/dev/null | hexdump -v -n 8 -e '1/1 "%02x"'
 }
 
+dir505_board_detect() {
+	local dev=$(find_mtd_part 'mac')
+	[ -z "$dev" ] && return
+
+	# The revision is stored at the beginning of the "mac" partition
+	local rev="$(LC_CTYPE=C awk -v 'FS=[^[:print:]]' '{print $1; exit}' $dev)"
+	AR71XX_MODEL="D-Link DIR-505 rev. $rev"
+}
+
 tplink_get_hwid() {
 	local part
 
@@ -471,6 +480,7 @@ ar71xx_board_detect() {
 		;;
 	*"DIR-505 rev. A1")
 		name="dir-505-a1"
+		dir505_board_detect
 		;;
 	*"DIR-600 rev. A1")
 		name="dir-600-a1"