Andrew,

quoted

From the high level, it looks like netcp switch meets the specifications

of a DSA hardware. Can you point me to a specific implementation that
I can use as an example to implement this for netcp?

You need two parts:

A tagging implementation, in net/dsa/tag_*.c. They are all pretty
similar, and all pretty simple.

A switch driver. driver/net/dsa/mv88e6060.c is the simplest. I would
suggest your first submission implements similar features as to what
this driver does. This is very minimalistic, but a good start. Once
that is accepted, you can incrementally add more features.

     Andrew