The tremendous amount of data generated by AI/ML driven applications and other hyperscale computing applications have forced the age old server architecture to change. The new architecture is driven by the resource disaggregation paradigm, wherein memory and storage are decoupled from the host CPU and managed independently through high-speed connectivity. The Compute Express Link (CXL) standard is a direct result of this evolution in the server architecture to support high-speed, low-latency, cache-coherent interconnect. The CXL specification delivers high-performance, while leveraging PCI Express® technology to support rapid adoption. CXL switching features resource pooling, enabling the host CPU to access one or more devices from the resources pool. While CXL 2.0 specification (CXL2) supports single-level switching, CXL 3.0 specification (CXL3) supports multi-level switching wherein the host CPU could leverage different resources in a tiered fashion. CXL3 also introduces fabric capabilities and management, improved memory sharing and pooling, enhanced coherency, and peer-to-peer communication. The spec also doubles the data rate to 64GT/s with no added latency over CXL2.

The specification is also evolving fast, with CXL3 released just three years after CXL1 was released. Truechip has a long track record of offering VIP solutions to a broad list of customers worldwide. It offers an extensive portfolio of VIP solutions to verify IP components interfacing with industry-standard protocols integrated into ASICs, FPGAs and SoCs. As a Verification IP Specialist, Truechip has been offering VIP solutions to support the CXL standard right from the start. For details on their entire portfolio of VIP offerings, visit the products page.  They recently expanded their portfolio with the addition of CXL3 and CXL Switch VIP solutions. You can read their press announcement about first customer shipment of CXL 3 verification IP and CXL switch model.

Truechip’s CXL3 VIP Solution

Truechip’s CXL Verification IP provides an effective and efficient way to verify the components interfacing with CXL connectivity of an IP or SoC. Their CXL VIP is fully compliant with the latest CXL specification. This solution is light weight with an easy plug-and-play interface so that there is no impact on the design cycle time. The solution is offered in native System Verilog (UVM/OVM/VMM) and Verilog.

The following Figure depicts a block diagram of the Truechip’s CXL3 VIP environment.

Some Salient Features

• Configurable as CXL Host and Device when operating in Flex Bus mode
• Configurable as PCI Express Root Complex and Device Endpoint when operating in PCIe mode
• Supports 64.0 GT/s Data Rate with backward compatibility
• Supports Pipe Specification 6.1.1 with both Low Pin Count and Serdes Architecture
• Supports Configurable timeout for all three layers
• Supports different CXL/PCIe Resets
• Supports Arbitration among the CXL.IO, CXL.cache and CXL.mem packets with interleaving of traffic between different CXL protocols
• Offers a comprehensive user API for callbacks
• Provides built-in Coverage analysis
• Supports all 3 coherency models HDM-D, HDM-H and HDM-DB to access HDM memory

Deliverables

CXL Host/Device

CXL BFM/Agents for:

• • Host and Device sequences
  • Transaction layer (CXL.IO and CXL.cache, CXL.mem)
  • Link layer (CXL.IO and CXL.cache, CXL.mem)
  • Arbiter/Mux layer
  • Phy layer

CXL Monitor and Scoreboard

Test Environment & Test Suite:

• • Basic and Directed Protocol Tests
  • Random Tests Error Scenario Tests
  • Cover Point Tests
  • Compliance Tests

Integration Guide, User Manual, Quick start Guide, FAQs and Release Notes

Truechip’s CXL Switch Model

Truechip’s CXL Verification VIP provides an effective & efficient way to verify the components interfacing with the CXL Switch interface of an IP or SoC. Truechip’s CXL Switch model is fully compliant with the latest CXL specification. The model supports Hot Add and Hot Remove for a CXL Device and is available in native System Verilog (UVM/OVM/VMM) and Verilog.

The following Figure depicts a block diagram of the CXL3 VIP environment when the system implementation incorporates the switching capability.

Aspects Common to All of Truechip’s VIP Solutions

Although covered in an earlier blog, it is worth to reiterate some advantages that cut across all of Truechip’s VIP solutions. All solutions come with an easy plug and-play interface to enable a rapid development cycle. The VIPs are highly configurable by the user to suit the verification environment. They also support a variety of error injection scenarios to help stress test the device under test (DUT). Their comprehensive documentation includes user guides for various scenarios of VIP/DUT integration. Truechip’s VIP solutions work with all industry-leading dynamic and formal verification simulators. The solutions also include Assertions that can be used in formal and dynamic verification as well as with emulations. And, their solutions come with the TruEYE GUI-based tool that makes debugging very easy. This patented debugging tool reduces debugging time by up to 50%.

For more information, refer to Truechip’s website.

Also Read:

Truechip’s Network-on-Chip (NoC) Silicon IP

Truechip’s DisplayPort 2.0 Verification IP (VIP) Solution

Bringing PCIe Gen 6 Devices to Market

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