1. A reusable hardware intellectual property (IP) protocol method for a system-on-chip device, capable of describing a hardware behavior via a software function, the method comprising: (A) determining whether any parameters are needed, corresponding to a determination of whether the hardware IP needs any parameters; wherein if parameters are needed, proceeding to step (B), and if not, proceeding to step (C); (B) inputting at least one function parameter, corresponding to input at least one function parameter to the hardware IP; (C) calling the software function corresponding to input a request signal to the hardware IP; (D) waiting for a return value from the software function corresponding to input an acknowledge signal to the hardware IP; (E) sending back the return value from the software function corresponding to output the result data from the hardware IP; and (F) ending the software function corresponding to reset or boot the hardware IP.