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pdewanga's avatar
pdewanga
Icon for New Contributor rankNew Contributor
3 years ago
Solved

Determining the Max payload size encoding

Hi Quartus Support Team,

Attaching the screen-shot from the "L- and H-tile Avalon® Streaming and Single Root I/O Virtualization (SRIOV) Intel® FPGA IP for PCI Express* User Guide" Table 43.

What is the encoded value of [2:0] Max payload size ?

is it something as follows -

000 -128Byte

001- 256Byte

010- 12Bytes

011-1024Byte

-----

------ or different ?

Also what is the encoded value in [5:3] Max rd req size ??

Please share more details about the encoded value of this 2 signals

[5:3] Max rd req size

[2:0] Max payload size

Thanks

  • Wincent_Altera's avatar
    Wincent_Altera
    3 years ago

    Hi,

    Thanks for correcting me, my apologize for misunderstanding the question.

    For your information the spec is not owned by intel, it is a general spec that all PCIe IP need to follow.

    You can get the detail in "PCI Express® Base Specification" in the web.

    For your question, I do help to printscreen it to you.

    Max rd req size

    Max payload size

    Hope this answer your question, Let me know if this is helpful to you.

    Regards,
    Wincent_Intel

7 Replies

  • Wincent_Altera's avatar
    Wincent_Altera
    Icon for Regular Contributor rankRegular Contributor
    3 years ago

    Hi,


    Thank you for reaching out.

    Just to let you know that Intel has received your support request and I am assigned to work on it.

    Allow me some time to look into your issue. I shall come back to you with findings.


    Thank you for your patience.


    Best regards,

    Wei Chuan


    • Wincent_Altera's avatar
      Wincent_Altera
      Icon for Regular Contributor rankRegular Contributor
      3 years ago

      Hi,

      From low level description, it is part of the Transaction Layer (TL) bus provides a subset of the information stored in the Configuration Space. Those Information on the Transaction Layer (TL) bus is time-division multiplexed (TDM). When tl_cfg_func[1:0]= 2'b00, tl_cfg_ctl[31:0] drives PF0 Configuration Space register values for eight consecutive cycles. The next 40 cycles are reserved. Then, the 48-cycle pattern repeats as per mention in the user guide.

      Can I know is there any specific reason asking that question ? do you facing problem on the configuration ?

      Regards,

      Wincent_Intel

      • pdewanga's avatar
        pdewanga
        Icon for New Contributor rankNew Contributor
        3 years ago

        Hi,

        The text you copy and pasted is from user guide, that we have gone through.

        There is no issue of configuration. I just want to use this two following signal for our design.

        [5:3] Max rd req size

        [2:0] Max payload size

        Actual question to make you more clear-

        question:- Please share more details about the encoded value of this signals ( [5:3] Max rd req size [2:0] Max payload size ). What does each state means ?

        Please don't copy paste the user guide content, We have gone through that but nothing is listed there properly.

        Thanks

  • Wincent_Altera's avatar
    Wincent_Altera
    Icon for Regular Contributor rankRegular Contributor
    3 years ago

    Hi,

    I wish to follow up with you about this case.

    I believe my previous reply answered your question, Do you have any further questions on this matter ?

    ​​​​​​​Else I would like to have your permission to close this forum ticket

    Regards,

    Wincent_Intel