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@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:)
Thanks, Peter
drivers/net/tsec.c | 3 ++- 1 files changed, 2 insertions(+), 1 deletions(-)
diff --git a/drivers/net/tsec.c b/drivers/net/tsec.c index 3f74118..cff5d38 100644 --- a/drivers/net/tsec.c +++ b/drivers/net/tsec.c @@ -276,12 +276,13 @@ uint tsec_local_mdio_read(volatile tsec_t *phyregs, uint phyid, uint regnum) | TBIANA_FULL_DUPLEX \ )
+/* Force the TBI PHY into 1000Mbps full duplex when in SGMII mode */ #define TBICR_SETTINGS ( \ TBICR_PHY_RESET \ - | TBICR_ANEG_ENABLE \ | TBICR_FULL_DUPLEX \ | TBICR_SPEED1_SET \ ) + /* Configure the TBI for SGMII operation */ static void tsec_configure_serdes(struct tsec_private *priv) {