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T2080 SGMII (SD1_c/d) network ping failed

Question asked by XIJUN GAN on Apr 20, 2019
Latest reply on Apr 23, 2019 by ufedor

I have a T2080 board customized base on t2080rdb-pcie. RCW field SRDS_PRTCL_S1/S2 are configured as 0x6C/0x29, so SD1_C/D are multiplexed as SG1/SG2 (SGMII MAC1 and MAC2 of Frame Manager). Both ports are connected to PHYs (ar8031 x2) and then routed to 2 RJ45 connectors.


SD1_REFCLK2 (PLL2 reference clock) are 100Mhz, this is measured and confirmed.  RCW field 'SRDS_PLL_REF_C
LK_SEL_S1' are configured to '00', that mean both PLL1 and PLL2 of SD1 are 100MHz. So, supplied reference clock and the setting are matched.


OS running is Linux, dts file configuration are:


fman0: fman@400000 {
   fm1mac1: ethernet@e0000 {
      phy-handle = <&sgmii_phy3>; 
      phy-connection-type = "sgmii";

   fm1mac2: ethernet@e2000 {
      phy-handle = <&sgmii_phy4>; 
      phy-connection-type = "sgmii";


   mdio0: mdio@fc000 {

      sgmii_phy3: ethernet-phy@3 {
         interrupts = <3 1 0 0>;
         reg = <0x3>;
      sgmii_phy4: ethernet-phy@4 {
         interrupts = <10 1 0 0>;
         reg = <0x0>;






PHY address of one ar8031 is 0, another one is 3, PHY address and mode (SGMII to 1000BaseT) were confirmed by measure pin of ar8031.


In the Linux rootfs console, instructions:

$ ifconfig fm1-mac1

// succeed, port brings up

$ ethtool fm1-mac1

// When insert network cable, 1000M/FD and linkup detected; when remove network cable, linkdown detected.

$ ping

// The opposite PC's ip is, ping failed

$ ifconfig fm1-mac1

// there are several tx-packets (caused by ping), no rx-packets, no error.


Test with 'fm1-mac2' get same result.



  1) The RCW configuration (serdes mux, serdes reference clock) are confirmed to be ok;

  2) The measured serdes reference clock is exactly same to what configured in RCW;

  3) The address of SGMII PHY (ar8031 x2) are confirmed to be ok;

  4) The mode of SGMII PHY (ar8031 x2) are confirmed to be ok;

  5) PHYs can correctly detect the link parameters (up/down, speed, fd/hd) when cable inserted or removed. 


But, the 2 sgmii ports are unable to ping.


Are there any limit about the reference clock of serdes (ex. it must be ready at the REST release)? Or are there anything we missed to check and confirm?


could someone help me to identify the trouble?


Great thanks!