RTL8366RB
The Realtek RTL8366RB is a 6-port Ethernet switch controller. It is used in a number of cheap wireless routers, for example the TP-LINK TL-WR1043ND. Since Realtek doesn't make data sheets publicly available anymore, it's hard to figure out how it works. While OpenWrt has a driver for configuring the chip, there's little documentation apart from the code. This page summaries what I was able to find out from reverse-engineering the OpenWrt driver.
Functional Description
The switch has five GMII ports for hooking up PHYs, plus a GMII port for talking to a CPU. Unlike the newer RTL8366S, the PHYs are external.
VLAN Support
Each port can be associated with one of 16 VLAN configuration entries. These entries determine the .1q VLAN ID (VID) as well as the .1q PCP for untagged frames.
In addition, a second table can optionally be used that has one entry per possible VLAN (4096).
VLAN Configuration Entries
| Reg. | Bits | Name | Description |
|---|---|---|---|
| 0 | 15 | - | unused |
| 0 | 14:12 | PCP | .1q Priority Code Point for ingress untagged frames. |
| 0 | 11:0 | VID | .1q VLAN ID for ingress untagged frames. |
| 1 | 15:14 | - | unused |
| 1 | 13 | UNTAG5 | On port 5, transmit egress frames from this VLAN without .1q tag. |
| 1 | 12 | UNTAG4 | On port 4, transmit egress frames from this VLAN without .1q tag. |
| 1 | 11 | UNTAG3 | On port 3, transmit egress frames from this VLAN without .1q tag. |
| 1 | 10 | UNTAG2 | On port 2, transmit egress frames from this VLAN without .1q tag. |
| 1 | 9 | UNTAG1 | On port 1, transmit egress frames from this VLAN without .1q tag. |
| 1 | 8 | UNTAG0 | On port 0, transmit egress frames from this VLAN without .1q tag. |
| 1 | 7:6 | - | unused |
| 1 | 5 | MEMBER5 | Port 5 is a member of this VLAN. |
| 1 | 4 | MEMBER4 | Port 4 is a member of this VLAN. |
| 1 | 3 | MEMBER3 | Port 3 is a member of this VLAN. |
| 1 | 2 | MEMBER2 | Port 2 is a member of this VLAN. |
| 1 | 1 | MEMBER1 | Port 1 is a member of this VLAN. |
| 1 | 0 | MEMBER0 | Port 0 is a member of this VLAN. |
| 2 | 15:3 | - | unused |
| 2 | 2:0 | FID | Use this FID value to differentiate forwarding lookups. |
