Following a four-year legal dispute, the Beijing IP Court ruled recently that Loongson Technology’s 3A5000 processor does not infringe upon MIPS Technologies’ chip architecture intellectual property rights.
Background Information
On June 2, 2021, Shanghai Cipunited Intelligent Technology Co., Ltd (“Cipunited”), affiliated with MIPS China, released a statement on its official website addressing claims circulating on various online platforms. These claims suggested that LoongSon Zhongke Technology Co. (“LoongSon”) had completely abandoned MIPS and launched its own instruction system. Cipunited clarified that such advertisements and reports are inaccurate, infringe upon Cipunited’s legitimate rights, and negatively impact the reputation of both the company and its partners, including MIPS.
Since 2011, LoongSon has entered into several technology licensing agreements with MIPS, which are limited to specific versions of the MIPS architecture or certain components. These licenses cannot be altered, expanded, or used without proper authorization. After obtaining exclusive rights to operate MIPS technology in China, Cipunited discovered that LoongSon had not fully complied with the agreements over the years, including delays and incomplete payments of licensing fees. According to the contract, any breaches should be subject to audit. In 2020, Cipunited requested a review in line with the contract terms; however, LoongSon did not cooperate to resolve the dispute. (Source: https://www.cipunited.com/cn/news/433.html)
LoongSon promptly responded, stating that the aforementioned comments constitute malicious slander and defamation against the company. It has initiated legal proceedings to protect its rights. On the same day, Cipunited requested that LoongSon immediately release the full manuals for its purportedly independently developed intellectual properties, “LoongISA” and “LoongArch,” and to publish the list of “LoongArch” research and development personnel in a timely manner, demonstrating LoongSon’s commitment to transparency and fairness. LoongSon has not responded to this request.
Dispute Overview
The core issue between Cipunited and LoongSon centers on whether LoongSon continues to use the MIPS instruction set, to which Cipunited holds exclusive rights. Cipunited asserts that LoongSon still incorporates the MIPS instruction set in its CPU designs while falsely claiming it as an independently developed instruction set, thereby avoiding royalty payments, misleading the public, and harming Cipunited’s reputation. LoongSon denies these allegations and considers them defamatory to its business.
CPU IP Classification
(1) Soft Core, Hard Core, and Solid Core
This classification is based on the form in which the CPU IP is provided.
- Soft Core: Delivered to users as HDL source code, soft cores undergo RTL-level design optimization and functional verification before being synthesized into gate-level netlists. They do not include specific physical design information, allowing users significant flexibility to modify and customize the design.
- Hard Core: These are physically designed based on semiconductor processes, with finalized circuit structures, technology layouts, and manufacturing processes that have been physically verified to meet various performance criteria. Hard cores are provided to users as complete circuit mask layouts along with comprehensive process files, often referred to as “ready-to-use” technology.
- Solid Core: Positioned between soft and hard cores, solid cores originate from soft cores but are mapped to standard cell libraries. They are typically delivered as gate-level netlists, offering a balance between flexibility and physical design readiness.
From a legal perspective, hard cores receive strong protection as integrated circuit layouts, whereas the protection of soft and solid cores is more nuanced and varies depending on the jurisdiction.
(2) CISC and RISC
This classification of CPUs is based on the complexity of the Instruction Set Architecture (ISA) they support. CISC (Complex Instruction Set Computing) CPUs feature variable instruction lengths, maintain continuous backward compatibility, and focus on efficient execution of their instruction sets. In contrast, RISC (Reduced Instruction Set Computing) CPUs use fixed-length instructions, have a simpler design, and achieve a higher chip area efficiency. This distinction is particularly significant when considering different technical approaches.
(3) Open Source and Closed Source
This classification of CPUs is based on the availability status of their instruction set architecture (ISA). A CPU is considered closed-source if its instruction set is proprietary and requires authorization for use. Conversely, an open-source CPU has an instruction set that is freely accessible. Examples of typical closed-source CPUs include x86, ARM, and POWER, while common open-source CPUs include OpenRISC, RISC-V, and Open POWER.
The importance of this classification lies in the differing copyright frameworks governing instruction sets, which influence whether they can be used freely and define the specific terms and scope of authorization for each.
CPU IP Protection
Types of Rights Protection for Integrated Circuits
Currently, integrated circuits are protected through several types of rights, including layout design rights, patent rights, and copyrights. These protections apply to various forms of integrated circuit designs. For example, a CPU, as a common type of integrated circuit, is safeguarded by these rights.
When an integrated circuit is represented as a schematic diagram, it may be eligible for copyright protection. If the design is expressed using hardware description language (HDL), it could be protected under both copyright and patent laws. Additionally, when the design takes the form of a layout, it is protected by exclusive layout design rights. It is important to recognize that integrated circuits can be protected by a combination of these rights simultaneously.
A key question arises regarding the appropriate form of protection for integrated circuit designs that use hardware description language (HDL) as their medium. Relying solely on copyright protection may not be suitable, as HDL designs differ significantly from traditional literary and artistic works. Furthermore, it is necessary to reconsider whether HDL designs qualify for software copyright protection, given the fundamental differences between software and hardware design. Software design typically involves pure logic at the application level, whereas hardware design focuses on state machine design based on timing circuits.
The protection of rights for hardware description language (HDL) designs in IC development varies depending on the specific technical characteristics of the design. If the HDL source code does not meet the criteria of a soft core, it can be protected under copyright law, as it is essentially similar to general written works. When the HDL source code qualifies as a soft core, protection options include both patents and software copyrights. For designs that meet the standards of a solid core or hard core, protection can extend to patents and exclusive layout design rights. If the HDL source code primarily represents algorithmic logic without involving specific gate circuits or hardware timing, it is typically protected as standard software under copyright law.
Regarding software and hardware protection, a CPU can be divided into two parts: the “hardware part,” which refers to the physical circuit components of the chip—commonly known as the IP Core—and the “software part,” which refers to the instruction set architecture (ISA) that the CPU recognizes and executes. The relationship between the IP Core and ISA is analogous to that between a person’s brain and the English words they know: the IP Core is the “brain,” while the ISA represents the “English words.” The ISA enables the development of various software applications, including operating systems, games, and office tools. Over time, widespread use of an ISA fosters a rich software ecosystem, much like how the long-term use of English has cultivated a diverse cultural and literary environment.
When designing a new CPU, the IP Core can either be developed in-house or acquired and modified from existing mature designs. For the ISA, there are two main approaches: using an existing ISA (which may be open source and free or closed source with licensing fees) or creating a new, custom ISA. However, as noted earlier, designing a new ISA presents significant challenges, primarily due to the lack of an established software ecosystem to support it.
When designing new CPUs, latecomer manufacturers typically develop their own IP cores to avoid royalty fees, while purchasing instruction set licenses from established CPU companies. The table below provides detailed information about the major domestic CPU design manufacturers in Mainland China that acquire instruction set licenses from US or UK CPU design firms.
Please note the differences in licensing models: ARM’s approach involves a costly instruction set license but a relatively inexpensive core license, allowing modifications to the core but not the instruction set. In contrast, MIPS offers a low-cost instruction set license but a more expensive core license, permitting changes to the instruction set but not the core. This licensing strategy has led to software ecosystem fragmentation in the case of MIPS.
According to Chinese copyright law, IP cores are protected under “hardware protection” to safeguard circuit designs, while instruction set architectures (ISAs) fall under “software protection” to preserve the software ecosystem.
Analysis of the MIPS and IPS Dispute
Legal Status of the MIPS Instruction Set
The term MIPS (Million Instructions Per Second) carries multiple meanings. Primarily, it refers to a CPU instruction set developed by the company MIPS, which was founded by John LeRoy Hennessy following a research project at Stanford University. Hennessy left Stanford in 1984 to establish MIPS. In 1992, SGI acquired MIPS Computer, Inc., and in 1998, MIPS separated from SGI to become MIPS Corporation. MIPS CPUs have been predominantly designed for applications such as routers and set-top boxes, which has limited their visibility among general consumers compared to brands like Intel. Although strategic market missteps have led to a decline in market share, the MIPS instruction set ecosystem remains well-established.
Overview of Cipunited and LoongSon
Cipunited was established in Shanghai on December 26, 2018. Its chairman, Wei-Ling He, was part of the original engineering team at MIPS in Silicon Valley. In early 2019, Cipunited acquired exclusive commercial rights to operate MIPS technology in China from Wave Computing, including over 30 MIPS customers. The company holds permanent worldwide patent licenses for CPU cores, including infrastructure, MIPS instruction set architecture-compatible CPU core licenses and sublicenses, and over 1,000 related patents. Cipunited also focuses on optimizing existing CPU core performance, developing new and derivative CPU cores, and supporting advanced technology initiatives and international projects for both domestic and global clients.
In essence, all Chinese companies utilizing the MIPS instruction set are required to pay royalties to Cipunited. Furthermore, all patent licensing agreements and collaborations involving MIPS CPUs within China are now managed by Cipunited.
LoongSon has been using the MIPS instruction set since 2001 when it began CPU design. During that period, MIPS sued LoongSon for unauthorized use, which was later resolved through royalty payments. Up until 2019, LoongSon’s “LongSon” series CPUs employed the MIPS instruction set. In April of this year, LoongSon publicly announced that it had transitioned away from the MIPS instruction set, adopting its self-developed LoongArch instruction set for the design of the LoongSon 3A5000 processor, which has been officially licensed.
Cipunited has alleged that LoongSon has been delinquent in royalty payments since 2011 and has requested repayment as well as disclosure of information related to the new processor. Industry standards typically require such disclosure unless the processor is not intended for commercial use or for technical personnel to learn its operation. LoongSon denies these claims, and to date, no further legal proceedings have been initiated by either party.
Legal Considerations
This case, while involving advanced technology, centers on two straightforward legal questions. First, whether LoongSon has breached its patent licensing contract or if Cipunited has harmed LoongSon’s reputation. Second, whether LoongSon has fulfilled its royalty payment obligations from 2011 to 2021. Resolving the first issue hinges on determining if LoongSon’s LoongArch instruction set is derived from or compatible with the MIPS instruction set, including any modifications or extensions. If it is, LoongSon would be in serious breach of contract and liable for damages to Cipunited. If not, Cipunited would be responsible for defamation and would need to issue a public apology and mitigate any negative impact.
To establish this, reviewing the LoongArch instruction set manual is essential. Therefore, Cipunited’s request for the full disclosure of the LoongISA and LoongArch manuals is justified. Should LoongSon refuse to provide this information, Cipunited can initiate an intellectual property lawsuit and request that LoongSon submit CPU samples incorporating the latest instruction set for comparison. Under Articles 24 and 25 of the Supreme People’s Court Provisions on Evidence in Intellectual Property Civil Proceedings, failure to comply without valid reasons may lead the court to presume the opposing party’s claims are valid, placing LoongSon at a disadvantage. If LoongSon provides the CPU claimed to use its own instruction set, it would be straightforward for a computer science professional to write assembly programs to verify the instruction set in use, thereby determining if LoongSon continues to utilize the MIPS instruction set and, if so, confirming a breach of contract.
Regarding the second issue, since LoongSon does not dispute its use of the MIPS instruction set until 2020, it is obligated to pay the corresponding royalties for the period from 2011 to 2020 to Cipunited.We will continue to follow up the case.