PCIe Initialization

From PEL Wiki

I cheated and just used _inl()_ and _outl()_ to directly read and write the PCIe configuration registers. I set the PCIe bridge to respond to requests for prefetchable memory in the address range I was targeting (0x200000000 - 0x201000000). Then I set the graphics card Base Address Register to the same address range and made sure that the memory decoding was enabled.

I did this right when the kernel is decoding the memory information from the motherboard.