DMA Mapping
Expansion bus master accesses to memory may need to target HT and main memory locations that are beyond the range of the expansion bus. Five registers within the address remapping block combine to define one or more DMA mappings within HT address space. Each DMA mapping is intended to provide a separate range of memory space for each bus master on the expansion bus. Note also that the corresponding DMA Control field enables or disables each DMA mapping range. The definition and use of each DMA register is defined below.
Number of DMA Mappings
This read-only register defines the number of DMA mappings implemented by the bridge. The specification recommends that one set of DMA fields be allocated for each device (bus master) on the ...
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