I got around to solder and get serial access to the WAX206. After using @sumo git branch to build an initramfs and playing around with the device tree I'm as wise (or dump) as before.
Preface: Unfortunately I don't have much (if any) embedded dev knowledge, I'm more of a (un)trained monkey with some programming and debugging skills.
I was setting the phy-mode and speed keys to the same value as in the Netgear provided device tree. OpenWrt is happy and reports all successs in the logs but no traffic over either lan or wan (`tcpdump -i eth0 -vvv) except DHCP client broadcast for wan (from WAX206 itself). The lan1-4 port do register if the network cable is disconnected or connected (ethtool). ethtool reports the wan port always got a link not matter what.
Looking into the source provided by Netgear for v1.0.4.0 there's a patch that adds handling of the RTL8221B IRQ in the mt753x (file target/linux/mediatek/patches-4.4/1007-822x-irq.patch in WAX_V1.0.40_SOURCE) as an external phy. I assume that's the reason why in their DTS there's ext-phy and ext-phy-reset-gpio in the mac@0 node.
cat /proc/interrupts on Netgears firmware lists the interrupts for RTL8221B:
69: 1 0 mt-eint 53 Level gsw@0
93: 0 0 mt-eint 77 Edge rtl822x_irq
In the current OpenWrt initramfs there's no IRQ 77.
A few questions:
- Does anyone know if something similar is needed to make it work on OpenWrt?
- The
phy-modeis set tosgmii, is that the right mode even for 2.5GbE (since I read that SGMII only supports speed up to 1+a-bit Gbit)?
*Are there ways to confirm how the RTL8221B is connected without an oscilloscope. It is to assume it's via port 5 of mk7531 but is that for sure? - Is there a way to get the phy ID of the RTL8221B chip used?
- Is there a way to see if the RTL8221B chips is recognised and a driver loaded?
And to finish it off: I found a partly similar setup in MTK830 + RTL8221B-VB-CG 2.5G question
.The 2.5G port connected mk7531 seems not to work either.