PCI Agent Unsupported Request Handling via IOSF Bridge
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
The integration of diverse intellectual property blocks into a single system-on-chip (SoC) is complex due to varying requirements and design uniqueness, especially when incorporating PCIe™ devices that need to handle Unsupported Request (UR) responses, which is not supported by the legacy PCI specification.
Innovation Solution
Implementing a set of rules and logic within PCI IP agents to enable them to respond with PCIe™-specific error responses, such as Unsupported Request completion responses, and using the integrated on-chip system fabric (IOSF) specification to standardize the interconnect protocol, allowing for efficient design and reuse across different types of chips.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If PCI devices are designed according to legacy PCI specification, then compatibility with legacy systems is maintained, but they cannot handle PCIe-specific error responses like Unsupported Request completion responses
Solution Approach 1:
A bridge device is introduced as an intermediary between PCI devices and PCIe devices. The bridge translates PCIe-specific error responses (like Unsupported Request completion responses) into legacy PCI-compatible signals (like DEVSEL# de-assertion), allowing PCI devices to communicate with PCIe switches without needing native PCIe error handling capability
Solution Approach 2:
The bridge device performs multiple functions: it acts as a PCIe to PCI translator, error response adapter, and protocol converter simultaneously. This multi-functionality allows a single component to resolve the compatibility issue between legacy PCI devices and modern PCIe infrastructure
2Adaptability or versatility
If diverse IP blocks are integrated into a single SoC, then functionality and versatility are improved, but design complexity increases due to varying requirements and interface specifications
Solution Approach 1:
The IOSF fabric provides a universal interconnect protocol that can accommodate multiple types of IP blocks (PCI, PCIe, USB, SATA, etc.) through a single standardized interface. This eliminates the need for specialized wires and communication protocols for each IP block type, reducing integration complexity while maintaining functionality
Solution Approach 2:
The IOSF fabric uses configurable parameters and control signals to adapt the same physical infrastructure to different protocol requirements. By changing operational parameters rather than physical architecture, the system supports diverse IP blocks without increasing structural complexity
Data Source
AI summary
In one embodiment, the present invention includes a method for handling a request received in an agent designed in accordance with a peripheral component interconnect (PCI) specification using PCI Express™ semantics. More specifically, responsive to determining that the agent does not support the request, an unsupported request detection register of the agent can be updated, and a response sent from the agent to indicate that the agent does not support the request. Other embodiments are described and claimed.