SiFive Is Setting Silicon Free with Open-Source Chips

Moore's Law is dead, just not in the way everyone thinks. SiFive believes open source hardware is the way forward for the semiconductor industry.

Moore's Law is dead...just not in the way everyone thinks. Technological advances keep allowing chips to scale, but the economics are another story – particularly for smaller companies that can't afford chips in the volumes that the big chipmakers would like from their customers.

The solution, according to San Francisco-based startup, SiFive, is open-source hardware, specifically an architecture developed by the company's founders called RISC-V (pronounced “risk-five”). Done right SiFive, which was awarded Startup of the Year at the 2016 Creativity in Electronics (ACE) Awards, believes that RISC-V will do for the hardware industry what Linux has done for software.

The Freedom Everywhere 310 from SiFive is the industry's first commercially available system on a chip based on the free and open RISC-V architecture. (Image source: SiFive]

“We've talked about the demise of Moore's Law for so long it's kind of become this Chicken Little, 'the sky is falling' story," Jack Kang, VP of Product and Business Development at SiFive told Design News. "But now it's happening”

Kang said that Moore's Law is not dead in the sense that chipmakers can still manufacturer smaller transistors that are faster and lower-power, “But we can't make them any cheaper. We're still making transistors smaller, going to smaller nodes, but it's no longer economically feasible for many customers in many markets to go to these nodes. Before, we could just go to the next node and things would be better, faster, and cheaper, now it's no longer cheaper. In fact, it's getting way more expensive.”

Which is not necessarily a problem for the Apples, Samsungs, and IBMs of the world, but what about the smaller companies, startups, even makers and inventors? “For traditional chip companies the ideal customer is one customer at an infinite volume,” Kang said. But the proposition has placed chipmakers into a position where they must function like venture capitalists, only doling out chip hardware instead of investment dollars. “With each customer that comes in chipmakers are trying to gauge if they're going to be successful,” Kang said. “They're looking at justifying the cost. And the design cost is becoming prohibitive for all but a very few companies.” He added that this is only compounded by the growth of Internet of Things (IoT) technologies, which is creating more and more market fragmentation.

But it's not just customers feeling the squeeze according the Kang. The push for growth on the part of chipmakers is also running into a wall in terms of supporting customers, begging a question that has become the core of SiFive's philosophy: Why can't the customers support themselves? The deepest levels of traditional chip hardware are locked off from customers (closed if you will), meaning any time a customer runs into an inevitable software bug that they must then return to the chipmaker for a fix. Not to mention they're restricted in what they can build around the chip. “Even the Raspberry Pi is a great example of quote 'open-source hardware,' but then the chip is not open-source. You hear things from developers like, 'I can't use the video accelerator inside the chip because it's a black box,' ” Kang said.

“Open source makes so much sense because then customers can be self sufficient,” Kang said. “If I'm a chipmaker and I'm going to support all these customers in all of these fragmented markets I can't scale out to a thousand if I have to put a dedicated software engineer on my team for each customer.”

RISC-y Business

That's where RISC-V comes in. “Our business model is helping those customers who probably wouldn't even get a call back from the chip guys because their volumes are too small or their markets are unproven,” Kang said. “We fundamentally can help them build custom chips at very low upfront cost. We do this by customizing it and by leveraging open source.”

Despite its precarious-sounding name, reduced instruction set computing (RISC) is actually based on a sound design principle. The idea, which dates back to the 1980s, is that a chip can perform best when a a simplified instruction set, which links hardware to software, is combined with a hardware architecture that uses fewer microprocessor cycles per instruction. Essentially, it's doing more with less.

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Up until RISC-V, RISC existed mainly in academic and research settings. In a 2014 research paper, Krste Asanovic, a professor at the Electronic Engineering and Computer Sciences Department at the University of California, Berkeley, argued that an open instruction set would not only reduce costs on the software end, but would also spur hardware innovation more so than closed/licensed instruction sets. “Given that the industry has been revolutionized by open standards and open source software—with networking protocols like TCP/IP and operating systems (OS) like Linux—why is one of the most important interfaces proprietary?” Asanovic, who is also a co-founder and the Chief Architect at SiFive, wrote. “While instruction set architectures (ISAs) may be proprietary for historical or business reasons, there is no good technical reason for the lack of free, open ISAs...”

RISC-V grew out of Asanovic's research. Since developing it, he has also started The RISC-V Foundation, which holds regular workshops around the technology.

Custom Silicon For All

In November SiFive unveiled the first of its products under its aptly-named Freedom Everywhere family of systems on a chip (SoCs), the FE310. Targeted at microcontroller, embedded, IoT, and wearables applications, the FE310 features a 32-bit core running at 320 MHz speed, according to the company. The register-transfer level (RTL) code for FE310 is completely open-source, meaning that developers can create software for the chip as well as customize their own SoC on top of the FE310. The company has also released an Arduino-compatible development kit around the FE310 called the HiFive1.

“Open sourcing the RTL encourages people to write software for [the SoC] and it builds a very robust ecosystem,” Kang said. “You can come to us, we have a base platform and we'll customize it to your requirements. You don't have to be a chip guy, just tell us what you want. We will take in your specs, do the customization and we'll deliver packaged tested parts. We'll give you a chip.”

Kang said the whole point for SiFive is drive down the upfront costs of prototyping, so that companies can get that first chip as cheaply as possible. “We can build a Freedom Everywhere platform for under $100,000, which is probably less than your CPU license from the bigger guys,” Kang said. “You don't have to buy a crappy off-the-shelf solution that you just stick together; you don't have to go to an FPGA because you can't afford chips.”

For those concerned about their intellectual property (IP), the company is quick to clarify that only the base platform is open source. Customers are free to make their own IP open source if they want, but it doesn't have to be.

Scaling Up Open Source

The next step for SiFive, according to Kang, is to further develop its base platform products. This includes the rollout of the Freedom Unleashed family of products, beginning with the U500, a 64-bit, 1.6 GHz multiprocessor aimed at larger enterprise data server applications including machine learning, computer vision, package inspection, and other networking and storage applications. “These are things people are trying to offload from the main server,” Kang said. “And as soon as you want to do acceleration that just screams customization. The reason we have the two different platforms is this is where we see a lot of customization requirements and a lot of fragmentation in the market.”

SiFive is also aiming for increased automation in its factories, with the goal of eventually turning out 1000 customer projects per year. “We believe in lowering costs so as many people as possible – whether they be starters, makers, hackers, ect. – can try their ideas,” Kang said. “Most of them will probably fail and that's fine. But the more people that try, the more better ideas that come out, newer things will come out, and some of them will be successful.”

Ultimately, Kang would like SiFive's message to the masses to be that anyone can can afford custom silicon.

“And SiFive can scale with you. If you are successful we can ship you millions of chips per year.”

Chris Wiltz is the Managing Editor of Design News  

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