[OpenWrt-Devel] [PATCH] mpc85xx: fix WAN/LAN-MAC for TP-LINK TL-WDR4900 v1

[Bastian Bittorf]

This works around a bootloader issue where every device
has the same lan/wan-mac 00:04:9f:ef:01:01 - with this patch
we read the macs from config-partition during initial network
setup. We have 9 valid macs stored in the partition, the
1st two are used for the radios, 3 and 4 are now used for WAN/LAN.

on an already setup / running device we can get the real macs with
. /lib/functions.sh
. /lib/functions/system.sh
echo "LAN = $(mtd_get_mac_binary config 338)"
echo "WAN = $(mtd_get_mac_binary config 344)"

see:
https://dev.openwrt.org/ticket/14714

from the ticket / user klondike:
U-Boot passed this commit https://gitorious.org/0xlab-kernel/u-boot/commit/ecd1a09b81f2ed6e6ba7bd1d0bfb0cc3d0ea2ad0
http://u-boot.10912.n7.nabble.com/U-Boot-PATCH-mpc83xx-remove-hardcoded-network-addresses-from-config-files-td44372.html
I suppose to prevent this particular issue, but the WDR4900 may be using an old bootloader still affected.
                                                                   ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^

I have been checking the contents of the dtb on the flash, this particular bit is quite revealing:

ethernet at b0000 {
                        #address-cells = <0x1>;
                        #size-cells = <0x1>;
                        device_type = "network";
                        model = "eTSEC";
                        compatible = "fsl,etsec2";
                        fsl,num_rx_queues = <0x8>;
                        fsl,num_tx_queues = <0x8>;
                        local-mac-address = [00 00 00 00 00 00];
                                             ^^^^^^^^^^^^^^^^^

                        interrupt-parent = <0x2>;
                        phy-handle = <0x3>;
                        phy-connection-type = "rgmii-id";
                        ptimer-handle = <0x4>;

                        queue-group at 0 {
                                #address-cells = <0x1>;
                                #size-cells = <0x1>;
                                reg = <0xb0000 0x1000>;
                                rx-bit-map = <0xff>;
                                tx-bit-map = <0xff>;
                                interrupts = <0x1d 0x2 0x1e 0x2 0x22 0x2>;
                        };
                };

I also have been checking the live device map to find this:

root at GHS-AP3:~# hexdump -C /proc/device-tree/soc at ffe00000/ethernet at b0000/local-mac-address
00000000  00 04 9f ef 01 01                                 |......|
00000006
root at GHS-AP3:~# hexdump -C /proc/device-tree/soc at ffe00000/ethernet at b1000/local-mac-address
*
root at GHS-AP3:~# hexdump -C /proc/device-tree/soc at ffe00000/ethernet at b2000/local-mac-address
*

My conclussion is that U-Boot most likely finds the device and (as no valid MAC-address is provided)
falls back to the default MAC provided by the old code, the kernel then receives thee modified
device map from U-Boot and assumes this is the correct MAC for the device despite it obviously isn't.

This can be seen at
target/linux/mpc85xx/patches-3.10/140-powerpc-85xx-tl-wdr4900-v1-support.patch

The enetaddr is filled up by using the device tree data by the process_boot_dtb
function and used by the platform_fixups function to set the eth0 address
(by calling dt_fixup_mac_address_by_alias("ethernet0", enetaddr); ).
But instead we should be used the device address which to my understanding is
provided in the mtd.

Signed-off-by: Bastian Bittorf <bittorf at bluebottle.com>
---
 .../mpc85xx/base-files/etc/uci-defaults/02_network |   26 ++++----------------
 1 files changed, 5 insertions(+), 21 deletions(-)

diff --git a/target/linux/mpc85xx/base-files/etc/uci-defaults/02_network b/target/linux/mpc85xx/base-files/etc/uci-defaults/02_network
index 10a2cc8..e4e3566 100755
--- a/target/linux/mpc85xx/base-files/etc/uci-defaults/02_network
+++ b/target/linux/mpc85xx/base-files/etc/uci-defaults/02_network
@@ -1,22 +1,5 @@
 #!/bin/sh
-#
-# Copyright (C) 2013 OpenWrt.org
-#
-
-tplink_set_mac()
-{
-	local cfg=$1
-	local offset=$2
-	local mac
-
-	. /lib/functions.sh
-
-	mac=$(mtd_get_mac_binary u-boot 326656)
-	mac=$(macaddr_add $mac $offset)
-
-	ucidef_set_interface_macaddr $cfg $mac
-}
-
+# Copyright (C) 2014 OpenWrt.org
 
 [ -e /etc/config/network ] && exit 0
 
@@ -24,6 +7,8 @@ touch /etc/config/network
 
 . /lib/functions/uci-defaults.sh
 . /lib/mpc85xx.sh
+. /lib/functions.sh
+. /lib/functions/system.sh
 
 ucidef_set_interface_loopback
 
@@ -35,10 +20,9 @@ tl-wdr4900-v1)
 	ucidef_add_switch "switch0" "1" "1"
 	ucidef_add_switch_vlan "switch0" "1" "0t 2 3 4 5"
 	ucidef_add_switch_vlan "switch0" "2" "0t 1"
-	tplink_set_mac lan -2
-	tplink_set_mac wan 1
+	ucidef_set_interface_macaddr lan "$(mtd_get_mac_binary config 338)"
+	ucidef_set_interface_macaddr wan "$(mtd_get_mac_binary config 344)"
 	;;
-
 *)
 	ucidef_set_interfaces_lan_wan "eth0" "eth1"
 	;;
-- 
1.7.2.5
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