How can i make eim interface with fpga using multiple dma?

[hanseunglee]

Hello everyone!!

I have a question.!

I want to make interface i.mx6 solo and FPGA use EIM(with sdma).

I've already tested with that using eim.

But, it is not working very well.

                              |      |      |      |      |      |   <= inturrupts (200us interval)

dma channel 0      |-----|

dma channel 1             |-----|

dma channel 2                    |-----|

....   

However, this method did not work well because of the schemeler of dma.

How can I make dma without being pushed back to match the interrupt signal?

[j_araya]

igorpadykov‌, hanseunglee‌

I would like to ask a follow-up question on this topic:

What if I just need an interface between a FPGA and the i.mx6's RAM by using a single SDMA channel? As far as I understand, I could use the "External Memory to External Memory Script" provided in the Reference Manual.

The question is:

Would the script be already implemented in the kernel if I compile it with "DMA Engine support" or do I need to write a driver myself to manage the communication between the EIM port and the i.mx6?

Note: I have seen that some devices i.e. UART have a DMA section in the Device Tree for them to carry out the communication through the SDMA, would that be necessary for the EIM in this case as well?

Thanks!

Jose

[igorpadykov]

Hi Jose

no, by default NXP Linux does not support sdma with EIM module.

There are some sdma tutorials which may be helpful:

Freescale i.MX SDMA tutorial (part I) 

Best regards
igor

[igorpadykov]

Hi Hanseung

seems that can be accomplished developing custom sdma script,

this may be developed with help of Professional Services

NXP Professional Services|NXP 

Best regards
igor
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