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AM3358: Disable automatic packet padding

Devaprasad GR
Intellectual 310 points

Is there a way(using some bit in a register) to disable automatic RX padding of incoming packets in CPSW hardware

  • 0
    TI__Mastermind 27890 points

    Hmmm...good question. I'm not aware of a way to do this, but I'll ask the IP designer and post the response here. I should have the answer early next week.

  • 0 in reply to -DK-
    TI__Mastermind 27890 points

    Hello, the feedback I got was "Can you get a better description of the question from the customer?  What exactly is being padded?

    Is this from host to Ethernet?".

  • 0 in reply to -DK-
    Intellectual 310 points

    Let me give an example. Packet coming from external world is of length 34Bytes(Generated using packet generator tool). Once the packet reaches the EMAC, it is zero padded and the new length  now is 64Bytes(Minum Ethernet Frame size).

    In general, packet of length less than 64Bytes is zero padded my the EMAC and sent as 64Bytes. Is there a way in hardware to disable this automatic RX padding.?  Some of the Intel MAC's do provide the feature of disabling Automatic RX padding. Do we have any such option here in AM335x EMAC.?

  • 0 in reply to Devaprasad GR
    TI__Mastermind 27890 points

    Hi,

    Here is the update from the designer:

    Short packets received on Ethernet ports are dropped. Short packets greater than 32 bytes sent by the host to Ethernet are padded and sent.  The host needs to not send packets if they are shorter than desired. Also, for quite a while there has been a p0_rx_pad bit (in CPSW_CONTROL) that causes short packets to be padded and sent or dropped.