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rMa1's avatar
rMa1
Icon for New Contributor rankNew Contributor
5 years ago
Solved

How to set descriptor length dynamically in PCIe Hard IP (AVMM-DMA interface)

In my system, data stream has different length in the three mode, for example, we need descriptor length=128 in mode1, and descriptor length=32 in mode2, descriptor length=100 in mode3, mode set by H...
  • KhaiChein_Y_Intel's avatar
    KhaiChein_Y_Intel
    5 years ago

    Hi,


    We do not receive any response from you to the previous question/reply/answer that I have provided. This thread will be transitioned to community support. If you have a new question, feel free to open a new thread to get the support from Intel experts. Otherwise, the community users will continue to help you on this thread. Thank you


    Best regards,

    KhaiY


KhaiChein_Y_Intel's avatar
KhaiChein_Y_Intel
Icon for Regular Contributor rankRegular Contributor
5 years ago

Hi Vicky,


The RD_TABLE_SIZE can be set to a new value after all previous programmed DMA descriptor are completed with no pending transaction and the last pointer register has been written with 0.


The driver, can set this register to 16, then write a new value of last pointer to restart the DMA operation.


Thanks

Best regards,

KhaiY


rMa1's avatar
rMa1
Icon for New Contributor rankNew Contributor
5 years ago

Hi KhaiY,

Our driver designer could not change RD_TABLE_ZISE when the path is idle, do you have the detail description about this?

I want to talk with you about this by phone or online meeting if you could support.

[email protected]

Vicky

  • rMa1's avatar
    rMa1
    Icon for New Contributor rankNew Contributor
    5 years ago

    Hi KhaiY，

    I want to explain the details again, when driver set the new value to the RD_TABLE_SIZE register, example RD_TABLE_SIZE=16(set RD_TABLE_SIZE=128 before， after power on), the operation in the descriptor is also go over the 128 descriptor but not 16, just like this register are wrote invalid, but there is no any alarm.

    Vicky