System and method for I/O access mode selection

摘要

A system and method for controlling the operation of an adapter operable in a plurality of modes, such as I/O mode and memory mapped mode. A generic adapter access routine is initialized with global data objects as pointers to corresponding sets of alternative adapter functions, and the adapter is initialized to function in a first mode and the pointers mapped to a corresponding current set of adapter functions. Device driver code calls to global data objects are executed by reference to the current set of adapter functions. Responsive to a request to switch modes, the adapter is switched to a second mode and the pointers remapped to a corresponding second set of adapter functions, and execution of device driver code calls to the global data objects continues.