[U-Boot] [PATCH] tsec: Force TBI PHY to 1000Mbps full duplex in SGMII mode

[Peter Tyser]

On Tue, 2009-11-03 at 17:52 -0600, Peter Tyser wrote:
> In SGMII mode the link between a processor's internal TBI PHY and an
> external PHY should always be 1000Mbps, full duplex.  Also, the SGMII
> interface between an internal TBI PHY and external PHY does not
> support in-band auto-negotation.
> 
> Previously, when configured for SGMII mode a TBI PHY would attempt to
> restart auto-negotation during initializtion.  This auto-negotation
> between a TBI PHY and external PHY would fail and result in unusable
> ethernet operation.
> 
> Forcing the TBI PHY and and external PHY to link at 1000Mbps full duplex
> in SGMII mode resolves this issue of auto-negotation failing.
> 
> Note that 10Mbps and 100Mbps operation is still possible on the external
> side of the external PHY even when SGMII is operating at 1000Mbps.
> The SGMII interface still operates at 1000Mbps, but each byte of data
> is repeated 100 or 10 times for 10/100Mbps and the external PHY handles
> converting this data stream into proper 10/100Mbps signalling.
> 
> Signed-off-by: Peter Tyser <ptyser at xes-inc.com>
> ---
> In-band SGMII auto-negotiation doesn't work according to a lengthy
> discussion with a Freescale FAE and the AN3869 SGMII appnote.  XES's
> MPC8572 and MPC8640 boards need this patch in order to use ethernet. These
> boards generally use SGMII to connect to an BCM5482S PHY which has
> an external gigabit-capable copper or fiber interface.
> 
> Some of Freescale's reference platforms have an SGMII riser card - any
> idea how those function when using auto-negotiation?  Do they function?
> Are the really using SGMII, or are they using 1000 Base-X?
> 
> Some of the info in the manuals is misleading/confusing so any comments
> are more than welcome from Freescalers:)

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