Data transfer from HPS to FPGA and conversely

Hi everybody,

In my project I have a FPGA module which reads inputs from INPUT_RAM and stores outputs in OUTPUT_RAM (both rams are altsyncram memories).

Inputs are computed in a Linux application running on the HPS and this application needs outputs produced by the FPGA module.

So the dataflow should be something like this:

1) HPS computes inputs

2) inputs are transferred from hps to input_ram

3) FPGA module computes outputs and stores them in OUTPUT_RAM

3) outputs are transferred from output_ram to hps

4) HPS uses outputs for its purposes

I've successfully managed to map INPUT_RAM and OUTPUT_RAM as Avalon MM slaves in the HPS memory space (with mmap()...) but this approach is too slow.

I think I should use the f2h_sdram interface to transfer data with a SGDMA or a mSGDMA controller, am I right?

Can someone give me a easy explanation about this possibility?

Thank you in advance!