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Observer dulatsi
Observer
6,027 Views
Registered: ‎06-26-2013

AXI DMA: Cyclic DMA Mode

Hi community,

 

we are using the AXI Direct Memory Access (AXI DMA) IP in multichannel mode (and thus scatter-gather mode, too).

We are running Vivado 2013.3 targeting a Zynq on a ZC702.

 

Apparently AXI DMA now supports a “Cyclic DMA Mode”. Anybody out there ever successfully used it?

 

As we are programming bare-metal we are using the “xaxidma.h” driver. Looking at its API (and at “xaxidma_bdring.h”) I can’t find any support for enabling cyclic DMA.

 

So the question would be: how to enable cyclic DMA by means of xaxidma.h?

How would I set up the last BD?

 

Thanks a lot for your help / advice / tip!

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5 Replies
Visitor nocomer
Visitor
5,965 Views
Registered: ‎11-29-2013

Re: AXI DMA: Cyclic DMA Mode

Hi All,

 

I also have a question about AXI DMA and cyclic DMA mode. Is cyclic DMA supported in Linux driver for AXI DMA?

I looked at drivers/dma/xilinx/xilinx_axidma.c and found device_prep_slave_sg only. Did I miss something?

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Observer qswsjs
Observer
5,309 Views
Registered: ‎07-18-2013

Re: AXI DMA: Cyclic DMA Mode

I have the  question too,have you solved the problem ?can you share it,thanks!

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Moderator
Moderator
5,262 Views
Registered: ‎06-29-2011

Re: AXI DMA: Cyclic DMA Mode

Hi all,

 

The AXI DMA version supplied with v2013.3 of the tools did not support Cyclic DMA mode as described in the PG021. This was an error in the documentation as support was only due to be added at this stage in an upcoming version of the core.

 

I believe support was added in AXI DMA v8.0 which can been seen from v2014.1 of the Vivado tools.

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Kind regards,
Gareth
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Observer qswsjs
Observer
4,970 Views
Registered: ‎07-18-2013

Re: AXI DMA: Cyclic DMA Mode

Hi garethc,

          Does the AXI DMA version 7.1 supplied with v2014.2 of vivado support Cyclic DMA mode ? I have config the AXI DMA V7.1 in scatter gather cyclic mode , but when I have transfered the last descriptor buffer,the tready of DMA pull down ,it doesnt transfer to the first descriptor again ! Do you know the problem ? please give me some advice ,thanks! 

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Observer qswsjs
Observer
4,954 Views
Registered: ‎07-18-2013

Re: AXI DMA: Cyclic DMA Mode

 Hi,nocomer

        Do you have got the  cyclic DMA supported in Linux driver for AXI DMA  ? Thanks!

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