Verification of system on chip integrated communication controllers

This article presents an approach used to verify communication controllers developed for Systems on Chip (SOC) at MCST. We provide a list of communication controllers developed in MCST and present their characteristics. We describe principles of communication controller’s operation on transaction, data link and physical layers and highlight their similarities. Then we describe a common method of device verification: principles of test system design, constrained random test stimuli generation and checking of device behavior. Based on common features of the controllers, we provide the general design of their test system. It includes components to work with transaction level interface (system agent of system on chip communication protocol) and physical interface (physical agent of protocol for SOC communication on a single board), configuration agent that determines device mode of operation and a scoreboard. Because controllers only execute transformation of transactions between different representation, scoreboard checks accordance of in and outgoing transactions. In addition, we describe specific features of devices that require the adjustments to the common approach. We describe how verification of those features affected the design of different test systems. We explain how a replacement of a physical agent with a second communication controller allows to speed up the development of test systems. We explain challenges of link training and status state machine (LTSSM) verification. We provide a way to work with devices with direct memory access (DMA) in a system agent. In conclusion, we present a list of found errors and directions of further research.