How to add x32 ABI support to PCI driver

Im trying to port the PCI driver(supports only 32 bit) from 2.6.31 )o the latest kernel version using openSuse. Im doing it version by version. I was able to port it till 3.1 kernel version. In the kernel 3.4 there is feature called X32 ABI support. I'm not knowing how to add this. Could anyone tell me what exactly this is and how to add this feature and what should I be changing ? Regards, OH