The phy chip DP83TG720S cannot be driven on the zynqmp utralScale+ board

[Dereck-327]

When I use DP83TG720S on petalinux, the driver can be loaded normally, and the phy can be loaded normally, but data packets cannot be sent or received. Here is the problem situation:

  dmesg | grep mac
  [    4.726983] macb ff0b0000.ethernet: Not enabling partial store and forward
  [    4.949728] macb ff0b0000.ethernet eth0: Cadence GEM rev 0x50070106 at 0xff0b0000 irq 38 (26:e0:0e:17:75:38)
  [    5.169861] systemd[1]: Initializing machine ID from random generator.
  [    8.315867] macb ff0b0000.ethernet eth0: PHY [ff0b0000.ethernet-ffffffff:00] driver [TI DP83TG720CS1.1] (irq=POLL)
  [    8.326244] macb ff0b0000.ethernet eth0: configuring for phy/rgmii-id link mode
  [    8.352156] macb ff0b0000.ethernet: gem-ptp-timer ptp clock registered.
  [    9.372016] macb ff0b0000.ethernet eth0: Link is Up - 1Gbps/Full - flow control off

  ifconfig eth0
  eth0 Link encap:Ethernet HWaddr 26:E0:0E:17:75:38 
  inet addr:192.168.1.10 Bcast:192.168.1.255 Mask:255.255.255.0 
  inet6 addr: fe80::24e0:eff:fe17:7538/64 Scope:Link 
  UP BROADCAST RUNNING MULTICAST MTU:1500 Metric:1 
  RX packets:0 errors:0 dropped:0 overruns:0 frame:0 
  TX packets:20 errors:0 dropped:0 overruns:0 carrier:0 
  collisions:0 txqueuelen:1000 
  RX bytes:0 (0.0 B) TX bytes:1801 (1.7 KiB) 
  Interrupt:38

And I can't ping my PC.

  ping 192.168.1.111
  PING 192.168.1.111 (192.168.1.111): 56 data bytes
  ^C
  --- 192.168.1.111 ping statistics ---
  633 packets transmitted, 0 packets received, 100% packet loss

This is my device tree description:

  &gem0 {
      status = "okay";
      phy-mode = "rgmii-id";
      phy-handle = <&phy0>;
      
      mdio {
          #address-cells = <1>;
          #size-cells = <0>;
          
          phy0: ethernet-phy@0 {
              reg = <0>;
              compatible = "ethernet-phy-id2000.a284", "ethernet-phy-ieee802.3-c22"; 
              ti,rx-internal-delay-ps = <2000>;
              ti,tx-internal-delay-ps = <2000>; 
              ti,fifo-depth = <1>; 
          };
      };
  };

However, the device tree is described using fixed-link, and it works fine.

  &gem0 {
  	status = "okay";
  	compatible = "cdns,zynq-gem", "cdns,gem";
  	phy-mode = "rgmii-id";
  	
  	fixed-link {
  		speed = <1000>;
  		full-duplex;
  		pause;
  		asym-pause;
  	};
  };

The linux version I use is 5.15.36-xilinx-v2022.2

:~# uname -r
5.15.36-xilinx-v2022.2

[Dereck-327]

The device is set to slave mode, and the box for converting the car Ethernet to regular Ethernet on the other end of the PC is set to master mode. The same situation occurs in this case.

&gem0 {
    status = "okay";
    phy-mode = "rgmii-id";
    phy-handle = <&phy0>;
    
    mdio {
        #address-cells = <1>;
        #size-cells = <0>;
        
        phy0: ethernet-phy@0 {
            reg = <0>;
            master-slave-cfg = "slave-force";
        };
    };
};

[e-mayhew]

Is the link partner configured in 1G forced speed as well? Assuming both automotive PHYs are linked, failure to communicate is likely due to RGMII delay timing. Please try attempting link/communication while tuning delay through DTS or directly through registers 0x602 and 0x430:

              ti,rx-internal-delay-ps = <2000>;
              ti,tx-internal-delay-ps = <2000>; 

Thank you,
Evan

[Wisdom-Lord]

Thank you for providing detailed information. According to your description, the DP83TG720S can load both the driver and PHY normally on the Petalinux system, but it fails to send or receive data packets. You have tried various configurations, including using device tree descriptions and fixed link modes, but the issue persists.


Dereck-327 and e-mayhew's comments provided valuable insights. In particular, e-mayhew suggested checking if the link partner is also configured for forced 1G speed and trying to adjust the delay timing through DTS or directly via registers. You can further check the RGMII delay timing settings and ensure the link partner configuration is consistent.


Additionally, you can try the following steps:

1. Confirm that the PHY is correctly configured in slave mode.

2. Check if the interrupt and DMA configuration is correct.

3. Try updating the driver or using a different version of Petalinux.

If the issue persists, it is recommended to provide more details about the hardware connection and configuration for further analysis.

Thank you for your patience. We look forward to your further feedback.