Intel Extensible Firmware Interface - Manual (Page 495)

Protocols — PCI Bus Support
Version 1.10 12/01/02 12-77
All the PCI transactions generated by this function are guaranteed to be completed before this
function returns. All the PCI write transactions generated by this function will follow the write
ordering and completion rules defined in the PCI Specification. However, if the memory-mapped
I/O region being accessed by this function has the
EFI_PCI_ATTRIBUTE_MEMORY_CACHED
attribute set, then the transactions will follow the ordering rules defined by the processor
architecture.
Status Codes Returned
EFI_SUCCESS The data was copied from one memory region to another memory region.
EFI_INVALID_PARAMETER Width is invalid.
EFI_UNSUPPORTED DestBarIndex not valid for this PCI controller.
EFI_UNSUPPORTED SrcBarIndex not valid for this PCI controller.
EFI_UNSUPPORTED The address range specified by DestOffset , Width , and Count
is not valid for the PCI BAR specified by DestBarIndex .
EFI_UNSUPPORTED The address range specified by SrcOffset , Width , and Count is
not valid for the PCI BAR specified by SrcBarIndex .
EFI_OUT_OF_RESOURCES The request could not be completed due to a lack of resources.