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RTOS/66AK2H14: SGMII link is not stable

mahima shanbag
Expert 1585 points
Part Number: 66AK2H14

Tool/software: TI-RTOS

Hi,

We have designed a customized board with 66AK2H14.

In our board we have 3 66AK2H14 processor ,out of which 1 is configured as Centralized Processor (Called CP henceforth) and 2 Distributing Processors (Called DP henceforth).

We have added one Ethernet switch(Microsemi's VSC 7429) between processor and RJ45 connector and 4 SGMII ports from each processor is connected to Ethernet switch.

Purpose of the switch is just to multiplex the SGMII ports as per customer requirement.

We have configured the Ethernet switch.

When I try to run the EMAC example in non loop back mode , it runs successfully and sent 10 packets out.

But in the switch i didn't receive any packets and SGMII link is not stable in Ethernet switch. It is  toggling.

Now my question is

Q1. Whether there is any extra configurationis needed in 66AK2H14  side to connect to Ethernet switch? Because I tested same EMAC example on the EVM and I was able to see the packet transmission in the   

       Wireshark.

Q2. I raised the same query to Microsemi , they suggested me to disable EEE in 66AK2H14 side, but I didn't find anything in the Gigabit Ethernet (GbE) Switch Subsystem user guide to disable EEE.

      How to disable it?

Please help me with this.

Thanks and Regards,

Mahima Shanbag

  • 0
    TI__Guru* 95265 points
    Hi,

    Is Microsemi Ethernet switch also SGMII interface? When you configure the K2H side, what is the connection type?
    - SGMII to SGMII with Autonegotiation Configuration? who is master and who is slave?
    - SGMII to SGMII with Forced Link Configuration?
    Please check the KeyStone Architecture Gigabit Ethernet (GbE) Switch Subsystem, section 2.4.3.

    The EMAC example we have is SGMII to PHY Configuration, because we connect the SGMII to RJ-45. You need to modify that code.

    Can you elaborate what is "EEE"?

    Regards, Eric
  • 0 in reply to lding
    Expert 1585 points
    Hi Eric,

    Thanks for your quick reply..

    >>Is Microsemi Ethernet switch also SGMII interface?
    Yes. SGMII ports of K2H is connected to Microsemi Ethernet switch's SGMII.

    >>When you configure the K2H side, what is the connection type?
    SERDES_SGMII.
    I have configured the SGMII as per KeyStone Architecture Gigabit Ethernet (GbE) Switch Subsystem, section 2.4.3 , SGMII to SGMII with Forced Link Configuration.

    >>The EMAC example we have is SGMII to PHY Configuration, because we connect the SGMII to RJ-45. You need to modify that code.
    I have already modified the SGMII configuration. Is there any other modification needed?

    >> Can you elaborate what is "EEE"?
    reduces the power consumption of physical layer devices (PHYs) during periods of low link utilization. EEE saves energy by putting part of the transmission circuit into low power mode when the link is idle. EEE specifies a signaling protocol, Low Power Idle (LPI) for achieving the power saving during the idle time of Ethernet links.


    Regards,
    Mahima Shanbag
  • 0 in reply to mahima shanbag
    TI__Mastermind 46460 points

    Mahima,

    EEE is a PHY feature as you stated above.  The SGMII interface in the 66AK2H14 is a MAC interface.  There is no EEE mode to disable.

    Since the Microsemi Ethernet switch ports are also MAC ports, you need to have one designated as SGMII slave (MAC mode) and one as SGMII master (PHY mode / emulation).

    I do not understand your Ethernet topology.  Please attach a simple diagram showing the SGMII ports connected between the 66AK2H14 processors and the Microsemi Ethernet switch.

    Tom

  • 0 in reply to Tom Johnson 16214
    Expert 1585 points

    Hi Tom,

    Thank you.

    >>Since the Microsemi Ethernet switch ports are also MAC ports, you need to have one designated as SGMII slave (MAC mode) and one as SGMII master (PHY mode / emulation).

    Actually I chose forced link configuration as auto-negotiation is disabled in the Microsemi Ethernet switch.

    I have attached the ethernet topplogy for your reference. K2H SGMII ports are connected to Ethernet switch's SGMII. Ethernet switch has 12 internal PHY's and 4 of them are connected to RJ45.

    Ethernet_Switch_Implementation.ppt

    Regards,

    Mahima Shanbag

  • 0 in reply to mahima shanbag
    TI__Mastermind 46460 points

    Mahima,

    Why does the switch block diagram show 12 PHY blocks?  Does it truly connect directly to the RJ45 connectors with MDI pairs?

    Are you sure that the switch ports connected to the SOC are truly SGMII?  If they are SGMII, why would auto-negotiation be disabled?  Auto-negotiation is a primary feature of an SGMII link.

    Tom

  • 0 in reply to Tom Johnson 16214
    Expert 1585 points

    Hi Tom,

    >>Why does the switch block diagram show 12 PHY blocks?  Does it truly connect directly to the RJ45 connectors with MDI pairs?

    We are not using all 12 PHY's. We are using only 4 PHY ports. They just shown the multiplexing in the block diagram.

    4 PHYs are directly connected to RJ45 .

    >>Are you sure that the switch ports connected to the SOC are truly SGMII?

    Yes.

    I have attached the ethernet switch block diagram for your reference.

    Here is the connection between TI SOC SGMII and Ethernet switch.

    In software we have configured the ports as SGMII but we selected MAC interface as SerDes.

    So Microsemi suggested like,

     VTSS_PORT_INTERFACE_SERDES default indicates the PCS ANEG is disabled, so, you might need to disable the ANEG in the other end of  66AK2H14 interfaces.
     
    As per their suggestion I disabled the auto negotiation in K2H.
     
    Thanks and Regards,
    Mahima Shanbag

  • 0 in reply to mahima shanbag
    TI__Mastermind 46460 points

    Mahima,

    Do the SGMII ports on the Microsemi switch support auto-negotiation?  If so, we recommend that it be enabled.  Since you say the Microsemi ports are MAC ports (SGMII slave), you would configure the 66AK2H14 SGMII ports for auto-negotiation master.

    Tom

  • 0 in reply to Tom Johnson 16214
    TI__Guru* 95265 points
    Mahima,

    Are you able to try the suggestion of Tom? Please check the KeyStone Architecture Gigabit Ethernet (GbE) Switch Subsystem, section 2.4.3. for setting of auto-negotiation and mastership.

    Regards, Eric
  • 0 in reply to lding
    Expert 1585 points
    Hi Eric,

    I configured the K2H GBE switch as master and Ethernet switch as slave as per KeyStone Architecture Gigabit Ethernet (GbE) Switch Subsystem,
    section 2.4.3.
    But I didn't get linkup, stuck in the while loop checking for link up.
    I am currently checking the Ethernet switch configuration .
    Please suggest anything I have to check from K2H side.

    Thanks and Regards,
    Mahima Shanbag
  • 0 in reply to mahima shanbag
    TI__Guru* 95265 points
    Hi,

    I am not sure if anything you can check on K2H side. The SGMII link auto-negotiation is done by hardware. Can you program K2H SGMII as auto-neg slave and switch as master, will it help?

    Regards, Eric
  • 0 in reply to lding
    TI__Guru* 95265 points
    Hi Mahima,

    Do you have any update for the issue?

    Regards, Eric
  • 0 in reply to lding
    Expert 1585 points
    Hi Eric,

    Sorry , Micro semi support person is on vacation So I didn't get any updates.

    I will let you know once I get the support from them.

    Thanks and Regards,
    Mahima Shanbag
  • 0 in reply to mahima shanbag
    TI__Mastermind 46460 points
    Mahima,
    Is there any update to this discussion? If there is no further discussion in the coming week, we will close this thread.
    Tom