On Sat, 2021-03-13 at 02:45 +0100, Andrew Lunn wrote: > On Thu, Mar 11, 2021 at 02:18:13PM -0600, Robert Hancock wrote: > > When using a fixed-link configuration in SGMII mode, it's not really > > sensible to have auto-negotiation enabled since the link settings are > > fixed by definition. In other configurations, such as an SGMII > > connection to a PHY, it should generally be enabled. > > So how do you tell the PCS it should be doing 10Mbps over the SGMII > link? I'm assuming it is the PCS which does the bit replication, not > the MAC?
I'm not sure if this is the same for all devices using this Cadence IP, but the register documentation I have for the Xilinx UltraScale+ MPSoC we are using indicates this PCS is only capable of 1000 Mbps speeds: https://www.xilinx.com/html_docs/registers/ug1087/gem___pcs_control.html So it doesn't actually seem applicable in this case. > > I'm surprised you are even using SGMII with a fixed link. 1000BaseX is > the norm, and then you don't need to worry about the speed. > That would be a bit simpler, yes - but it seems like this hardware is set up more for SGMII mode - it's not entirely clear to me that 1000BaseX is supported in the hardware, and it's not currently supported in the driver that I can see. -- Robert Hancock Senior Hardware Designer, Calian Advanced Technologies www.calian.com
