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Getting the XxBD and packet information

Former Member

I have an XEmacPs ethernet object
I create a XEmacPs_Bd Template object
I clear it, XEmacPs_BdClear(&Template)
I clone it into the ring:
XEmacPs_BdRingClone(&(XEmacPs_GetRxRing(&ethernet)), &Template, XEMACPS_RECV)


Than I get a packet. Now, how do I check the contents of the packet I just received? I am assuming that I use the macro:
u32 blank = XEmacPs_BdRead(&(XEmacPs_GetRxRing(EmacPsInstancePtr)), XEMACPS_BD_ADDR_OFFSET);


Except that when I do that, I don't get anything meaningful out of it. The entire swath of memory at that address is all blank.


How do I get the current buffer descriptor? How do I follow it to the packet's data?

  • 0

    The XEmacPs object has, as part of its structure, the RxBdRing object, which has things such as:
    u32 BaseBdAddr; Is this the start of the BD.
    u32 PhysBaseAddr; How is this different than BaseBdAddr? Unless address translation is turned on?
    XEmacPs_Bd* FreeHead; Is this the "first" free BD in the ring?
    XEmacPs_Bd* HwHead; Is this the first BR in memory?

    But I still don't see how I get the "current" BD. The one that will be written to as soon as a packet is received.