That switch is based on a Realtek RTL838x/RTL839x SoC. An effort is currently underway to properly support these in openWRT and the mainline Linux kernel. First patch in OpenWRT is in:
https://git.openwrt.org/?p=openwrt/openwrt.git;a=commit;h=df...
These SoCs are used in a lot of consumer-level switches, so it's a target-rich environment! We're populating a wiki to keep track of it all, feel free to join in if you can help: