aws/aws-fpga

What is xdma0_user mapped to?

Quarky93 opened this issue · 3 comments

Quarky93 commented

Hi, I was under the assumption that xdma0_user would be mapped to one of the AXI-Lite interfaces similar to the standard Xilinx IP. However after some testing, I'm left confused. Can someone let me know is xdma0_user mapped to the sda, ocl, or bar1 axi-lite buses? Or must I use the AWS API? I would prefer to use xdma0_user to keep compatibility with on-prem cards using XDMA.

kyyalama2 commented

Dear customer

Thank you for your interest in AWS. The AWS FPGA PCIe Memory map is available at
https://github.com/aws/aws-fpga/blob/master/hdk/docs/AWS_Fpga_Pcie_Memory_Map.md#aws-fpga-pcie-memory-map

Please refer to the table here for information on mapping of PF/BAR address spaces. Please let us know if this is helpful or if you are looking for any additional information that can help with your debug

Thanks

Quarky93 commented

Hi, I'm aware of the BAR mapping. However I'm less certain on what the xdma driver actually maps to on the xdma0_user character device specifically.

Normally with on-prem FPGA with XDMA, the xdma0_user is mapped to the AXI-Lite bus. I'm not sure what it does on AWS F1.

Quarky93 commented

Ok, xdma0_user is mapped to OCL :) .
@kyyalama2 should this be documented?