@param Operation Indicates if the bus master is going to read or write to system memory.\r
@param HostAddress The system memory address to map to the DMA controller.\r
@param NumberOfBytes On input the number of bytes to map. On output the number of bytes\r
@param Operation Indicates if the bus master is going to read or write to system memory.\r
@param HostAddress The system memory address to map to the DMA controller.\r
@param NumberOfBytes On input the number of bytes to map. On output the number of bytes\r