If you remember, when TI decided to exit the booming wireless segment in 2012, the company decided to re-focus their application processor product line (OMAP) initially developed for smartphone “to a broader market including industrial clients like carmakers”. Being a TI employee in the 90’s in south of France, where TI has started the very successful wireless venture, I was feeling sad as it was the end of an amazing story. But I understood the business reasons and thought that it was a wise decision.
But the investment made by TI to develop OMAP had been huge, developing OMAP5 could be counted in thousands man.year, and the idea to target industrial market seems to be attractive. I was sharing this view, but I realize that I was naïve when thinking you can pick-up an existing SoC initially developed for wireless and decide to target automotive applications. These three words tell you why this was a naïve view: Reliability, Availability, Serviceability or RAS. The car pictured below is 58 years old. Do you really think that we will be able to use the first iPhone in 2065, even assuming that the proper network will be available?
One of Netspeed’ customers is a diversified company developing complex chips addressing server, automotive, and industrial market segments. Supporting automotive applications requires three criteria, safety, security, and reliability to outperform almost any other application. Safety because an automobile is a life-critical system, security because you don’t want to allow any malware to penetrate this system, and finally reliability as we all expect our car to be failure-free for years if not decades.
But SoC targeting certain automotive applications can be as complexes as application processors, integrating multiple CPU/GPU/DSP cores, which creates the need to design cache-coherent solutions. The company’s previous SoC was coherent, but the coherency solution was severely lacking flexibility and offered only limited configurability. The company’s new SoC architecture was targeting an increase in coherent bandwidth as well as the maximum possible flexibility, including a highly configurable coherency solution with design choices in multiple dimensions. To reach the lowest possible latency, the coherency architecture needed to scale with the number of coherency modules.
On top of these design challenges, which can be shared by SoC targeting other markets, comes the requirement to meet the ISO 26262 standard, specifically defined for the automotive market. To meet this high-reliability standard, architects wanted to provide a rich set of enterprise-class RAS (Reliability, Availability, Serviceability) features. Reliability can be linked with the Mean Time Between Failure (MTBF) and high reliability means the longest possible time before the system produces wrong outputs. Availability is the amount of time a device is actually operating as the percentage of total time it should be operating. Serviceability defines the simplicity and speed with which a system
can be repaired.
Since the company needed a coherency solution that was both highly configurable and fully scalable, NetSpeed was an obvious candidate since its Gemini NoC IP is the only product on the market that addresses both of these requirements. In fact, Gemini can satisfy requirements for both coherent and non-coherent designs and can also handle designs with a mix of coherent and non-coherent traffic. The company needed superior performance on coherent fabric to create differentiation from the competition. NetSpeed’s solution enabled it to meet its aggressive target of 100% increase in coherency bandwidth. Compared with the previous generation, the new SoC with NetSpeed’s superior coherency directory solution delivered ultra-low latency for the system, offering 25% improvement.
When deadlocks occur in a smartphone AP, it’s painful, but not tragic as you can simply reset the system by using On/Off button. Avoiding deadlocks can be life-critical for an automotive SoC! Using patented algorithms and formal methods to design NoCs that are correct-by-construction, NocStudio generated an architecture that was deadlock-free at the application level.
If you consider the long list of challenges directly linked with this SoC target application, automotive, you better understand why picking-up a smartphone AP and re-target this SoC to support the automotive market is attractive… but naïve. The SoC architect would have to rethink the architecture in respect with RAS requirements and flexible cache-coherency support, avoiding unacceptable deadlocks. Netspeed’ NocStudio would be the right cache-coherent NoC generator to help building such an automotive SoC.
This blog has been inspired by NetSpeed “Automotive SoC” Success Stories. You can read more about this story and Mobile AP, Networking, Digital Home SoC or Data Center Storage storieshere
From Eric Esteve