Arm is proposing a common framework to enable the next generation of chiplets. The company recently provided updates on two new initiatives that will help to deliver this framework:
Arm Chiplet System Architecture (CSA): Arm and a group of more than 20 partners are developing an Arm Chiplet System Architecture (CSA), which will enable greater reuse of components (physical design IP, soft IP etc) between multiple suppliers. The group is seeking to standardize around system design choices for different chiplet types, such as how to partition an Arm-based system across multiple chiplets, or their high-level properties (e.g. requirements for system memory or a Root of Trust).
Updating AMBA to standardize protocols for chiplets: For more than 27 years, AMBA has been a foundational open industry standard and AMBA specifications like AXI and CHI have been used in billions of devices.
- AMBA CHI is high speed, credited, and packetized, which makes it ideal for chiplets. The previously announced AMBA CHI C2C specification leverages the existing on-chip CHI protocol and defines how it is packetized, enabling it to be transported chip(let)-to-chip(let). The open specification is now formally released, after collaboration with a diverse set of partners across the industry.
- There are several existing AXI-based designs and Arm is committed to deliver an open AXI C2C specification that can be adopted by silicon vendors currently enjoying the benefits of AXI in their single chip designs.
The company says its investments in AMBA and CSA will enable partners to decompose an Arm-based system across multiple chiplets, in the same way a monolithic chip is composed of IP blocks.
Arm also intends to collaborate in the following areas:
- Physical layer: Industry standards. such as UCIe, are needed to define the physical layer for transporting data between chiplets within a package (for AMBA, PCIe and other protocols) and other non-differentiating aspects of system aggregation from chiplets.
- Protocols: Industry standard protocols, such as PCIe and CXL, alongside on-SoC interconnect protocols like AMBA, will enable the market to aggregate well-defined peripherals from across a motherboard into a package.
- High-level properties and partitioning : For Arm-based systems using AMBA protocols, there is an infinite flexibility to disaggregate the SoC into chiplets. CSA will help the Arm-ecosystem to reach consensus around the most valuable partitioning schemes to reduce fragmentation.
Here is a blog posting by Richard Grisenthwaite , EVP, Chief Architect & Fellow, Arm: