[U-Boot] Modify u-boot to let 8315 PCIe run in EP model

Hi,

I'm newbile, my task is to modify u-boot to support end point PCI express with Freescale MPC8315, The MPC8315(here it work in EP model) will connect to PC, and download RTOS image file to SDRAM though PCI express.

Can anyone give some suggestion about how to modify the u-boot to let 8315 PCIe run in EP model? Thanks in advance.