The OCP VIP is made of an active part driving the interface signals and a passive one, monitoring the timing correctness, phase ordering, etc., of interface signals resulting in two validation aspects. Regarding the active part, the so called Bus Functional Model (BFM), the qualification process is focussed on signal driving and as a consequence all the OCP features and all the OCP signals need to be activated.

For a qualification of the traffic, once a complete set of profiles has been created the associated tests can be efficiently shaped and executed. Tests can be random, semi random or deterministic and they can be applied to more than one configuration.

As a mere example, if the number of configurations is K and one test is usable for the 50% of the configurations, in case of T tests available the regression will be based on 0.5*T*K scenarios. Thanks to the randomization on tests, every scenario can be run several times and this will increase the number of executed tests and consequently the confidence on the VIP BFM quality.

During such process, the VIP monitor will check if signals were driven correctly and any failure or misconduct will provide elements to improve either the BFM or the monitor itself.

As previously mentioned VIP monitor is a static and dynamic protocol checker and it is a fully passive agent helping in protocol violation and forbidden configurations detection. As well as the BFM, it needs to be validated with respect to environments emulating both a faulty and correct behaviour; a faulty environment will cause the check to be alerted, a correct environment should not activate any of the checks.

If coverage is active on certain set of checks, tests and configurations can be further extended, verifying that each of those checks has been active. This means that the overall VIP robustness can be made even better by adding random error injection and running twice the full regression test. Benefits of the parallel approach are quite evident, because both driving and checking are cross validated.

This QP for OCP allows a reliable exploitation of protocol flexibility and interface configurability, Thanks to the QP qualification process, flexibility and configurability are trustfully mirrored into the VIP that can be easily reused in multiple OCP based projects, at any level.

Figure 3. Methodology in use at yogitech to qualify ocp vip at every new product version release

Quality and stability in an OCP VIP bring direct and indirect benefits to the user. The process of qualification of the OCP VIP also generates a reference model to be used for new OCP soft models creation.

In the following two cases are presented as examples: the first is a regression environment that the user can architect to validate its own OCP model, the second one represents a smooth migration path that starts from a VIP implemented with a powerful and mature object oriented language (the e-language) and it targets native System Verilog equivalent solution.