In our custom board, we have connected four sgmii ports to an Marvel switch. The switch is capable of performing auto negotiation. We are selecting the SGMII configuration in RCW. Will the eMAC does default auto negotiation with the switch or do i need to perform any configurations for SGMII serdes or eMAC to establish the gigabit link with switch. If so, how to configure the eMAC.
FM2 EMI1(MDIO) is used to configure the Ethernet switch. Each eMAC is having an MDIO. When this eMAC MDIO will be used. Do i need to use this MDIO to configure the SGMII which is connected to the ethernet switch.
U-Boot is capable to initialize mEMACs in accordance with selected SerDes protocol. No additional configuring for a mEMAC is needed in this case.
A Dedicated (external) MDIO interface can be used to configure connected PHY or switch (according to its data sheet) if this is required.
As you said, U-Boot does SGMII initializations as requested in RCW configurations. Auto negotiation and auto speed detections are enabled in both T4240 and also in the external Ethernet switch. Auto negotiation complete bit is set but link up is not set.
We have no suspect on the external Ethernet switch because the switch was able to auto-negotiate with the PHY connected on some other port of the Ethernet switch. What could be the possibilities the auto negotiation is set and link is not up between T4240 and switch.
Please create a Technical Case and provide in it additional information:
1) the processor connection schematics as searchable PDF
2) U-Boot booting log
The Technical Case creation link: