Hi Ido
 

First of all, I want to be sure that when we say "CPU port", we're
talking about the same thing. In mlxsw, the CPU port is a pipe between
the device and the host, through which all packets trapped to the host
go through. So, when a packet is trapped, the driver reads its Rx
descriptor, checks through which port it ingressed, resolves its netdev,
sets skb->dev accordingly and injects it to the Rx path via
netif_receive_skb(). The CPU port itself isn't represented using a
netdev.

With DSA, we have a real physical ethernet network interface for the
'cpu' port. It connects to one of the ports of the switch. Frames on
this interface have an extra header, indicating which switch port it
came from, and we do a similar resolving it to a slave netdev, strip
of the header and injecting it into the receiver path via
netif_receive_skb().

	Andrew