Re: [PATCH net-next] net: ethernet: ti: am65-cpsw: Add priv-flag for Switch VLAN Aware mode

Andrew Lunn
2024-02-28T13:36:58Z

> What if there is no kernel behavior associated with it? How can it be mimicked
> then?

Simple. Implement the feature in software in the kernel for
everybody. Then offload it to your hardware.

Your hardware is an accelerator. You use it to accelerate what linux
can already do. If Linux does not have the feature your accelerator
has, that accelerator feature goes unused.

> Please consider the following:
> Untagged packets sent from Software via the corresponding VLAN interfaces will
> be tagged which is the expected behavior. However, if this is offloaded, it will
> imply that even untagged packets that are simply forwarded in the Ethernet
> Switch and never get to software will also have to be tagged by the Ethernet
> Switch. This is not allowing the choice of leaving untagged packets as-is on the
> Ethernet Switch's forwarding path. This patch attempts to allow configuring
> something quite similar to this, where it is possible to *choose* whether or not
> to tag packets being forwarded.

So step back. Forget about your accelerator. Use just a Linux software
bridge. Describe what you want the Linux software bridge to do.

Andrew