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Visitor sungrace
Visitor
373 Views
Registered: ‎03-24-2018

Zynq Ultrascale DMA Controller question

I have very basic question:

- Zynq Ultrascale Soc has DMA Controller(s) (in PS).

- in PL, AXI DMA Controller IP is used for dma xfers.

Are both dma controllers used in the design or only one is used at any time to implement the dma xfers?

 

Regards

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3 Replies
Xilinx Employee
Xilinx Employee
271 Views
Registered: ‎01-09-2019

Re: Zynq Ultrascale DMA Controller question

Hello @sungrace,

Depending on your design you could use both or one or the other.  It really depends on what you want to do.  Some examples could be including multiple AXI DMA IPs in a single design to transmit to two seperate output data streams, or using an AXI DMA IP in conjunction with the PS DMA (ZDMA) to access data from both DDR and BRAM at the same time.  With multiple DMA at the same time there can be issues with arbitration, leading to some difficult design decisions in order to access or send out data efficiently.

This link has a post by @jg_bds about DMA which might be worth reading:

https://forums.xilinx.com/t5/AXI-Infrastructure/Using-AXI-DMA-to-read-and-write-DDR-with-custom-IP/m-p/931174#M2253

Thanks,

Caleb

 

Thanks,
Caleb
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Visitor sungrace
Visitor
257 Views
Registered: ‎03-24-2018

Re: Zynq Ultrascale DMA Controller question

Caleb

Thank you very much for your response.

Now I have a question about linux drivers for dma:

If I want to use ps dma controller, then the linux driver to be used is xilinx's dma engine client driver.

But if I use AXI DMA IP Softcore, I can use UIO driver.

Can you please let me know if this is correct or any other thoughts.

 

Regards

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Xilinx Employee
Xilinx Employee
243 Views
Registered: ‎10-04-2016

Re: Zynq Ultrascale DMA Controller question

Hi @sungrace,

Xilinx provides Linux drivers for both the hard DMA IPs and the soft DMA IPs.

The full list of drivers are here:

https://xilinx-wiki.atlassian.net/wiki/spaces/A/pages/18841873/Linux+Drivers

These are kernel drivers. This Wiki article explains how you could use them to perform transfers from user space. Even though the article is specific to AXI DMA, you could do something similar with the PS DMAs.

https://xilinx-wiki.atlassian.net/wiki/spaces/A/pages/18842418/Linux+DMA+From+User+Space

Regards,

Deanna

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