Re: [PATCH 3/3] dsa: add switch chip cascading support

[Lennert Buytenhek <buytenh@wantstofly.org>]

On Fri, Mar 20, 2009 at 09:16:18PM +0000, Ben Hutchings wrote:

> > For the example topology above, the dsa platform data would look
> > something like this:
> > 
> > 	static struct dsa_chip_data sw[2] = {
> > 		{
> > 			.mii_bus	= &foo,
> > 			.sw_addr	= 1,
> > 			.port_names[0]	= "p1",
> > 			.port_names[1]	= "p2",
> > 			.port_names[2]	= "p3",
> > 			.port_names[3]	= "p4",
> > 			.port_names[4]	= "p5",
> > 			.port_names[5]	= "p6",
> > 			.port_names[6]	= "p7",
> > 			.port_names[7]	= "p8",
> > 			.port_names[9]	= "dsa",
> > 			.port_names[10]	= "cpu",
> > 			.rtable		= (s8 []){ -1, 9, },
> [...]
> 
> Is there supposed to be a gap in the numbering here?  The diagram above
> seemed to number the ports 1-10 but I'm guessing the internal numbering
> of those would be 0-9.

Yeah, that was intended.  On this particular chip model, ports 0-7
are RJ45 ports, 8-9 are SERDES ports, and 10 can either be SERDES or
(R)GMII -- so 10 is a natural choice for the cpu port, 8 and 9 can
be used as interconnect ports to other switches, and 0-7 are used
to connect end-stations to.  If there was another switch chip, we
could connect it to port 8 of switch #0.