[U-Boot] [PATCH] revert "tsec: Force TBI PHY to 1000Mbps fullduplex in SGMII mode"

Peter Tyser ptyser at xes-inc.com
Thu Nov 18 16:34:11 CET 2010


<snip>

> >My understanding is that the SGMII link is always at 1000Mbps speed - see
> >figure 1 from the app note.  Additionally look at figure 3.  My understand
> >from it, and the app note's text is that SGMII auto-negotiation doesn't
> >really occur - its just passing the PHY-side auto-negotiation results to
> >the Freescale MAC, which software then configures.  I'm not sure what the
> >purpose of the "SGMII auto-negotiation" is - its not really auto-
> >negotiating and the same information can be read from the PHY via its MDIO
> >interface, which is what is happening on X-ES boards currently.
> 
> I guess the point is to save MDIO signals to the external PHY and read the
> negotiated result from the internal TBI PHY.

Do the P2020DS, MPC8572DS and P1/P2 RDB boards not have an MDIO
interface to their PHYs'?  I've never heard of a board that doesn't, and
would guess the tsec driver in U-Boot requires a PHY to be accessible
via MDIO to use the corresponding network interface.

I can forward you the email thread about SGMII auto-negotiation with
Freescale's FAE off-list if you'd like as well.

Best,
Peter



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