SiFive, a startup building chips based on the open-source RISC-V architecture, is adding more financial firepower to take on Arm. The company said last week it had raised $65.4 million in funding from Sutter Hill Ventures, Chengwei Capital, Spark Capital and other existing investors as well as new investor Qualcomm. The funding doubles its total amount raised to $129.5 million since being founded in 2016.
SiFive, which uses the RISC-V architecture to curb the cost of custom chip design, has also sold stakes to Intel, Samsung and SK Hynix—the world's three largest chip manufacturers. Qualcomm is not only the world's largest supplier of smartphone chips but also one of the biggest customers at SiFive rival Arm, which SoftBank bought for $32 billion in 2016. SiFive last year raised $50.6 million in what was previously its biggest funding round.
Qualcomm’s investment signals that the RISC-V architecture has become more than a distant threat to Arm. Qualcomm Ventures’ Quinn Li said “SiFive has established itself as a leader in the RISC-V space making significant contributions to the broader semiconductor industry" through its unique chip design process. Stefan Dyckerhoff of Sutter Hill Ventures said the startup "continues to drive rapid RISC-V growth, development and adoption."
Like Arm, SiFive offers its RISC-V IP to other suppliers, which incorporate it into chip designs before sending them to final production. But compared to Arm, SiFive aims to operate more like open source software vendors like Red Hat Software. The company has introduced a set of development tools that enable customers to add custom instructions to its RISC-V cores and make it much easier for them to commission custom chips from SiFive.
SiFive's tools can be used to affordably assemble its commercial RISC-V cores, proprietary customer IP, peripheral IP and partner IP into chips targeting the consumer and industrial Internet of Things. The company is aiming to curb the often prohibitive cost of custom chip development and reduce design time to between one and three months. SiFive also hopes to enable smaller engineering teams to follow Apple's lead in custom SoC design.
Since the RISC-V architecture is open source, anyone can add custom instructions on top of it—something Arm forbids. That gives customers a path to producing domain-specific designs that potentially offer lower power and higher performance than general-purpose silicon. SiFive's efforts to democratize chip design comes amid a slowdown in Moore's Law, the semiconductor industry's blueprint for building smaller, faster and cheaper chips.
The Silicon Valley-based company is enjoying some early success. SiFive has made more than 100 licenses available to customers using its RISC-V cores. Chips using them are shipping in products including a Huami smartwatch. "The paradigm has shifted," Naveed Sherwani, SiFive's chief executive, said in a statement. He added that the company’s RISC-V CPUs are "firmly on the map and the RISC-V revolution well and truly established."
The company's operations are also growing. Since its acquisition of Open Silicon in 2018, SiFive—founded by chief technology officer Yunsup Lee, chief architect Krste Asanovic and chief engineer Andrew Waterman in 2016—has started offering custom chip design services. Over the last year and a half, the company has grown from around 40 employees at the start of 2018 to more than 400 across 15 locations globally today, SiFive said.
Other companies are tapping the openness of the RISC-V architecture. Andes Technology has started selling commercial RISC-V CPU cores and tools customers can use to add instructions. Esperanto Technologies, a Silicon Valley startup, is building chips that contain thousands of RISC-V CPUs. Technology giants like Google are also among the 235 members of the RISC-V Foundation, though whether they have RISC-V plans is unclear.
Qualcomm, Nvidia and other major semiconductor suppliers are designing RISC-V CPUs to handle housekeeping chores inside chips instead of running applications. Qualcomm plans to install RISC-V CPUs in its smartphone processors, which industry analysts say could total hundreds of millions of unit shipments per year. Nvidia, which analysts say ships around 40 million graphics processors per year, also plans to add RISC-V cores to its GPUs.
That may be only the tip of the iceberg for the RISC-V architecture. SiFive offers customers 32-bit cores targeted at the Internet of Things and complements them with 64-bit cores that it says can be used to handle autonomous driving and artificial intelligence jobs in Internet of Things devices and data centers, among other applications. SiFive says it offers access to processor cores that rival Arm's Cortex-A, Cortex-R and Cortex-M products.
There is still rough road ahead for SiFive and other players in the RISC-V space. RISC-V holds a sliver of Arm's market share. Chips based on the Arm architecture dominate the smartphone space and are the foundation of most Internet of Things devices today. Around 23 billion Arm-based chips shipped in 2018, while RISC-V cores will be shipped inside 10 million to 100 million chips in 2019 alone, according to the RISC-V Foundation.