Complete processing of DMA mappings after an I/O transfer is finished.
Invalidate the caches for the memory descriptor. Defaults to true for kNonCoherent and is ignored by the other types.
Copy any buffered data back to the target IOMemoryDescriptor. Defaults to true, if synchronize() is being used to explicitly copy data, passing false may avoid an unneeded copy.
kIOReturnNotReady if not prepared, kIOReturnSuccess otherwise.
This method should not be called unless a prepare was previously issued; the prepare() and complete() must occur in pairs, before and after an I/O transfer