Apparatus and method for port polarity initialization in a shared i/o device

Abstract

An apparatus and method are provided that enable I/O devices to be shared among multiple operating system domains. The apparatus includes a first plurality of I/O ports, a second I/O port, and a plurality of port initialization logic elements. The first plurality of I/O ports is coupled to a plurality of operating system domains through a load-store fabric. Each of the first plurality of I/O ports routes transactions between the plurality of operating system domains and the switching apparatus. The second I/O port is coupled to a first shared input/output endpoint. The first shared input/output endpoint is configured to request/complete the transactions for each of the plurality of operating system domains. One of the plurality of port initialization logic elements is coupled to the second I/O port and remaining ones of the plurality of port initialization logic elements are each coupled to a corresponding one of the first plurality of I/O ports. The plurality of port initialization logic elements is configured to initialize corresponding links between each of the plurality of operating system domains and the switching apparatus, and between the first shared input/output endpoint and the switching apparatus, to support the transactions, where each of the plurality of port initialization logic elements automatically configures a corresponding polarity for each of the first plurality of I/O ports and the second I/O port, and where the corresponding polarity is in a default polarity prior to being configured.