navio2 odroid xu4 + level shifter shield

Hi guys, i wanted to know what it would take for me to port the current navio2/ardupilot to the xu4 using the level shifter shield. I know that there would need to be things set such a s anew platform for the xu4 specifying spi ports etc. Where is the actual gpio memory maps etc set. I have looked at raspilot and gotten it to compile on the xu4 but was not able to get any further as I did not know how to go about doing the gpio subsystem. Are there any resources out there that one can point me to for someone wanting to attempt or try this.