I am working on designing a custom PCI-Express card.

I am trying to write a kernel module that will DMA my custom card.

Right now when I plug the card into Linux no valid PCI device shows up (meaning I probably have a error on my end, I know) however, If I halt the system at startup in the bootloader (uboot) I am able to directly access the card as I know in uboot the physical memory address that is mapped to my device. 

Is there a way I can access the card in a simliar fashion on Linux?