Patent ID: 8429323

Claim:
A method comprising: receiving, at a north chip, a secondary bus identifier that identifies a bus that is immediately downstream from a bridge, a subordinate bus identifier that identifies a highest bus identifier of all of buses reachable downstream of the bridge, and an MMIO bus address range that comprises a memory base and a memory limit; in response to the receiving, writing, to the north chip, a translation of a bridge identifier that identifies the bridge and a south chip identifier that identifies a south chip that comprises the bridge to the secondary bus identifier, the subordinate bus identifier, and the MMIO bus address range; sending the secondary bus identifier, the subordinate bus identifier, the memory base, and the memory limit to the bridge, wherein the bridge stores the secondary bus identifier, the subordinate bus identifier, the memory base, and the memory limit in the bridge; receiving, at the north chip, an MMIO command that comprises an MMIO address; in response to the receiving the MMIO command, finding in the translation the MMIO bus address range that encompasses the MMIO address; in response to the finding in the translation the MMIO bus address range that encompasses the MMIO address, determining the bridge identifier and the south chip identifier that are assigned the MMIO bus address range that encompasses the MMIO address; adding the bridge identifier and the south chip identifier that are assigned the MMIO bus address range that encompasses the MMIO address to the MMIO command; sending the MMIO command to the south chip identified by the chip identifier; and wherein if the MMIO bus address range that is stored in the bridge encompasses the MMIO address in the MMIO command, then the bridge sends the MMIO command downstream to a bus connected to the egress port of the bridge, and wherein if the MMIO bus address range that is stored in the bridge does not encompass the MMIO address in the MMIO command, then the bridge does not send the MMIO command downstream to the bus connected to the egress port of the bridge.