Beagleboard C4 pin muxing

hello… Iam working on Beagle board rev c4. I have a preinstalled raw image of ubuntu 12.04 running on my board. I wish to access uart2_rx pin which is already multiplexed as gpio(mode 4). I have to make it mode 1. Can anyone please give a detailed steps on how to pin configure the multiplexed pin. I couldnt get much idea from elinux,org pinmuxing .