10-28-2014 01:21 AM
I'm using the AXI Direct Memory Access (AXI DMA) IP(v7.1) in cyclic mode (and thus scatter-gather mode, too).
We are running Vivado 2014.2 targeting a Zynq on a ZC702.PG021of AXI DMA(V7.1) says that it support cyclic mode!
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!
10-28-2014 07:06 AM
10-28-2014 07:16 PM
Thanks for your reply! I use AXI DMA linux driver xilinx_axidma.c,I applied for the descriptor,the driver use the API list_add_tail(&new->node, &first->tx_list) set tail descriptor's 'next descriptor' pointing back to the first descriptor.So I think I have set tail descriptor's 'next descriptor' pointing back to the first descriptor,to use an cyclic buffer descriptor. is it right?
Does the AXI DMA(V7.1) suppport cyclic mode? In another post（http://forums.xilinx.com/t5/Embedded-Processor-System-Design/AXI-DMA-Cyclic-DMA-Mode/m-p/386379/highlight/false#M10244）,someone say that in the AXI DMA (V8.0) to support the cyclic mode ? Can you help me confirm it? Thanks a lot ！
10-30-2014 07:17 PM
Sorry，I have another question ! Does the AXI DMA linux driver(xilinx_axidma.c) have been updated to supported cyclic mode?
As far as I know, Linux driver hasn't been updated to support. Do we need modify the linux driver to support cyclic mode?thanks!
10-30-2014 11:44 PM - edited 10-30-2014 11:45 PM
Yes you are right. Linux driver doesnt support cyclic mode.Its only in standalone driver.
I will raise a CR for this.
11-02-2014 05:39 PM
Thanks skitap for your reply!
I encountered this problem now, trapped here, no progress, when can you help me update the Linux driver to support cyclic mode? I'm very grateful to you help me to solve this problem!
12-21-2014 09:35 PM
09-09-2016 09:19 AM
So, what was the conclusion here, other than the linux driver is to be updated to support cyclic DMA?
It's just that I see this very same issue in simulation.
Is cycle BD mode broken?