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

[Andrew Lunn <andrew@lunn.ch>]

On Wed, Apr 09, 2025 at 03:12:53AM +0000, Ng, Boon Khai wrote:
> > 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)

Please add a comment, or describe this in the commit message.

	Andrew