We have abstracted the AD1939 audio codec as a Intel Qsys component with streaming stereo sinks and sources. The Line_In physical audio connection on the audio board that goes the the AD1939 ADC comes out the Line_In streaming source. In a similar manner the Mic_In physical comes out the Mic_In streaming source. To send data to the physical Line_Out connection that goes through the AD1939 DAC, we just send streaming data to the Line_Out Qsys sink.
Qsys allows a FPGA designer to connect streaming data paths in the data plane without having to manually create the network-on-chip bus interfaces.