The siba driver provides bhnd(4) support for devices based on the Sonic Inc. Silicon Backplane, an
interblock communications architecture found in earlier Broadcom Home Networking Division wireless
chipsets and embedded systems.
A common interconnect connects all of the Silicon Backplane's functional blocks. These functional
blocks, known as cores, use the Open Core Protocol (OCP) interface to communicate with agents attached to
the Silicon Backplane.
Each core can have an initiator agent that passes read and write requests onto the system backplane and a
target agent that returns responses to those requests. Not all cores contain both an initiator and a
target agent. Initiator agents are present in cores that contain host interfaces (PCI, PCMCIA), embedded
processors (MIPS), or DMA processors associated with communications cores.