11-25-2013 06:21 AM
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!
12-02-2013 04:33 AM
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?
09-08-2014 01:53 AM
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.
10-26-2014 08:07 PM
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!