Posted memory write verification

Abstract

A method for verifying the proper communication of data packets from an initiator device on a PCIe data bus to a target device on the data bus. A target-specific counter on the initiator is synchronized to an initiator-specific counter on the target with the same value. The initiator writes the value of the target-specific counter into the tag field of the packet header, and also writes an identifier of the initiator into the header. Then the initiator sends the packet to the target on the PCIe data bus. Upon receipt of the packet, the target reads the identifier and checks the value against the appropriate initiator-specific counter on the target. When the value is not equal to the initiator-specific counter on the target, then it generates an error message. An additional memory write with specific data is posted from the initiator to the target. A memory read is posted of the additional memory write location from the initiator to the target. The operation of the initiator is continued when a good status and data matching the additional write data is returned from the target, and operation is halted when an error status is returned or data that does not match the additional write data.