摘要 |
<p>A system and method of enhanced backplane messaging among a plurality of computer boards communicating over a common bus uses a set of pre-allocated buffers on each computer board to receive messages from other computer boards. Each sending computer board is represented on each remote computer board by a descriptor ring with pointers to pre-allocated buffers on that remote computer board. When a sending computer board has a message to deliver to a remote computer board, the sending computer board uses its DMA controller to transfer the message into the pre-allocated buffers on the remote computer board. The sending computer board also sends a mailbox interrupt to the remote computer board. The remote computer board interrupt handler searches its descriptor rings and manipulates a series of pointers to move messages from the descriptor rings to the intended receiving application(s). Pointer manipulation is also used to replenish the descriptor ring(s) with empty buffer(s). In addition, chained DMA transfers are used to eliminate any data transfers by the processor itself across the bus. The chained DMA transfers transfer messages to the pre-allocated buffers, set flags indicating that a message is present in a buffer, send a mailbox interrupt to the remote computer board, and read back the address of the next pre-allocated buffer for that descriptor ring.</p> |