Internal loopback test program for SMC 9218i LAN chip

Hi everyone,

I am in need of developing a internal loopback test for SMC 9218i LAN Chip without connecting any wires. Iam using a stratix2 processor in my board.The datasheet talks about a internal loopback mode where data will be looped back to the MAC itself but iam totally confused about programming for this.So hoping for some inputs from u guyz..plzzzz help..