Method and apparatus for implementing a single DMA controller to perform DMA operations for devices on multiple buses in docking stations, notebook and desktop computer system

摘要

A computer system (6,7) includes first and second I/O circuits (932, 934), 51, 97 first and second buses (904, 83) respectively coupled to the first and second I/O circuits (932, 934), 51, 97 a memory (106), a third bus (104) coupled to the memory (106), and first and second bus interface circuits (902, 6920) connected between the third bus (104) and the first and second buses (904, 83) respectively. A direct memory access (DMA) controller (910) is coupled to the first bus (904) and to the first bus interface circuit (902), and a serial communications circuit (7010, 6910, 7020) is connected between the DMA controller (910) and the second bus interface circuit (6920). As an example, in the present invention a single DMA controller may be used to provide DMA capability to both a notebook computer and a docking station, using an related information between the DMA controller and a requesting device in the docking station. Other devices, systems and methods are also disclosed.