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AM335x Ethernet connection issue

Hiroyasu Tazawa1
Guru 12350 points

Hi, Everyone

I have a qustion.
We use Ethernet of AM335x.

Ethernet connection stop after thhis connection.

We rearch register of AM335x.

Port Number on Unicast Address Table Entry Bit Values is changed after I get issue.

○AM335x TRM
www.ti.com/.../spruh73m.pdf
14.3.2.7.1.6 VLAN/Unicast Address Table Entry

AM335x initialize Port Number is 0 after boot.
but Port Number is changed 0 when Ethernet is not connect.
(Ping is not return)

It is stable if Port Number is 1 we changed

Is it possible to change Port Number by Hardware ?
We have not been changed in Software except initialization.

and It is stable if We changed Secure bit 0 to 1.
I want to know this reason too.

Best Regards
Hiroyasu

  • 0
    TI__Guru**** 393215 points
    I cannot understand what you are trying to do. On any network, if you loopback two ports on a switch the network becomes flooded and practically unusable.
  • 0 in reply to Biser Gatchev-XID
    TI__Mastermind 37395 points

    What OS is being used? If linux is the OS could you please post ethtool eth0? Need to see if there is a link status first. 

  • 0 in reply to Biser Gatchev-XID
    Guru 12350 points

    Hi, Biser

    I'm sorry. It was delay.
    I understand this loopback of two port unusable.
    but We guess End User sometimes mistake to connect two port. 

    Actually End User made this situation.We avoid this.

    We research all Ethernet register.
    This Port Number bit only is changed.
    We wanna know it is possible to change Port Number by Hardware
    and why ?

    We were modified secure bit is 1.
    and This situation is fixed.
    This modification is correct ?

    Best Regards
    Hiroyasu

  • 0 in reply to Schuyler Patton
    Guru 12350 points
    Hi, Patton

    We use μIton.
    but We ask you about register of AM335x.

    Best Regards
    Hiroyasu
  • 0 in reply to Hiroyasu Tazawa1
    Guru 12350 points
    Hi, Biser and Patton

    Do you have any information ?

    I wanna make sure whether to be correct secure bit is 1.
    Can you tell me if you need more information.

    Best Regards
    Hiroyasu
  • 0 in reply to Schuyler Patton
    Guru 12350 points

    Hi,Quote

    These are register dump.

    ■Index1
    14.3.2.7.1.6 VLAN/Unicast Address Table Entry

    (when Secure bit is ON)
    I/O   4A100D20 00000001 00000000 00000000 00000000 ................
    I/O   4A100D30 00000000 00000001 30020011 0E028064 ...........0d...
    I/O   4A100D40 00000003 00000003 00000003 00000000 ................

    (when Secure bit is OFF)
    I/O   4A100D20 00000001 00000000 00000000 00000000 ................
    I/O   4A100D30 00000000 00000000 30020011 0E028064 ...........0d...
    I/O   4A100D40 00000003 00000003 00000003 00000000 ................

    Packet Capture.zip

    and This is packet capture of Wireshark.

    Can you give me some advice ?


    Best Regards
    Hiroyasu

  • 0 in reply to Hiroyasu Tazawa1
    TI__Genius 10435 points

    The Learning/Updating/Touching Processes (14.3.2.7.3 in the TRM) are based on on the source MAC address of the incoming packet.

    In your case, the Updating Process (14.3.2.7.3.2 in the TRM) is occurring when a previously seen source MAC address (00:11:0E:02:80:64) enters the internal 3-port switch from a port that is different from the previous time. So, when packets with source address 00:11:0E:02:80:64 are entering the switch at external port 1 and everything is fine.

    However, at some point it appears like packets are entering the switch from internal host port 0 (sent by the ARM core presumably) using the same MAC address as its source address (00:11:0E:02:80:64). At this point the updating process occurs and IF the secure bit is set, the packet is dropped and no update occurs. If the secure bit is NOT set, then the address is updated to reflect the fact that the device has moved to host port 0.

    The root of your issue appears to be the fact that packets are leaving the ARM (entering the switch at host port 0) with the same MAC address that used to reside on external port 1.

    Jason Reeder

  • 0 in reply to Jason Reeder
    Guru 12350 points

    Hi, Quote

    Thank you.
    I got it.

    Best Reghards
    Hiroyasu