[PATCH net-next v3 2/2] net: stmmac: dwxgmac2: Add support for HW-accelerated VLAN stripping

[Ng, Boon Khai]

> This appears to be identical to dwmac4_wrback_get_rx_vlan_tci() ?
> 
> Can it be moved into the shared code, or am i missing something?
> 
>         Andrew

Hi Andrew thanks for the quick response.

For the dwmac4 IP it has the following format at the 
Receive Normal Descriptor 0 (RDES0)

           31                                                                                                0
              ------------------------------------- -----------------------------------
RDES0 |   Inner VLAN TAG [31:16]   | Outer VLAN TAG [31:16   |
              ------------------------------------- -----------------------------------

While for dwxgmac2 IP it has the following format at the RDES0
Depending on the Tunneled Frame bit (TNP)

For Non-Tunneled Frame (TNP=0)
           31                                                                                                0
              ------------------------------------- -----------------------------------
RDES0 |   Inner VLAN TAG [31:16 ]  | Outer VLAN TAG [31:16]   |
              ------------------------------------- -----------------------------------

For Tunneled Frame (TNP=1)
           31                                        8 7                          3 2                  0
              -------------------------------- ----------------------- ----------------
RDES0 |   VNID/VSID                    |    Reserved         | OL2L3         |
              -------------------------------- ----------------------- ----------------

While the logic for handling Tunneled Frame and Non-Tunneled
Frame is not yet implemented in the 
dwxgmac2_wrback_get_rx_vlan_tci() function, I believe it is
prudent to maintain separate functions within their respective
descriptor driver files, (dwxgmac2_descs.c and dwmac4_descs.c)