Thank you @igorpadykov for the reply,
We have already used PCIe on other modules, so the PCIe interface cannot be used. In addition, ecspi cannot meet the communication bandwidth requirements.So flexspi may be the best choiAce.
According to i.MX 8M Mini Applications Processor Reference Manual, Rev. 2, 08/2019, we did not find the specific details of how to communicate with FPGA. Do you have any application cases or the information can be referenced.