Chapter 18 covers the guidelines for implementing a UEFI Driver for a PCI device. The end of that chapter covers how to use the tools provided with the EDK II to convert one or more UEFI Drivers in PE/COFF image formats into a single PCI Option ROM image that may be included with a PCI add-in card.
When a PCI add-in card is installed into a target platform, the PCI Option ROM contents are discovered by the PCI Bus Driver and UEFI Drivers are loaded and executed automatically. No additional platform configuration should be required. Some platforms may provide setup options to enable/disable specific PCI slots or enable/disable the loading of PCI Option ROMs. If a UEFI Driver stored in a PCI Option ROM is not being loaded and executed, then check the platform firmware configuration screens.