PCIe Endpoint TLP Prefix Encoding for Transaction Attributes

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Solution Overview

Problem

The Peripheral Component Interconnect Express (PCIe) protocol lacks the ability to communicate transaction-specific attributes such as cacheable, bufferable, read-allocate, and write-allocate attributes, which are essential for improving efficiency and performance in complex integrated circuit communication within mobile communication devices.

Innovation Solution

A PCIe system is configured to encode these transaction-specific attributes in the transaction layer packet (TLP) prefix and provide them to the host system, allowing the PCIe endpoint to determine and encode these attributes, and the host system to detect and parse them, thereby enhancing communication efficiency and performance without violating the existing PCIe standard.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If PCIe protocol uses standard TLP format without extensions, then compliance with PCIe standard is maintained, but ability to communicate transaction-specific attributes is lost

Engineering Contradiction:
ImprovePCIe standard complianceVSAvoidtransaction-specific attributes
Core Design Contradiction:
ReliabilityVSLoss of information

Solution Approach 1:

The patent embeds transaction-specific attributes within the existing TLP structure by utilizing the reserved byte 7 and extending byte 6, nesting additional information within the established PCIe packet format without disrupting the outer structure

Inventive Principle:
Principle #7Nested doll (Nesting)

Solution Approach 2:

The patent modifies the TLP parameter structure by reinterpreting and extending existing fields (bytes 6 and 7) to carry additional attribute information, changing the data encoding parameters while maintaining structural compatibility

Inventive Principle:
Principle #35Parameter changes

2Productivity

If PCIe protocol includes transaction-specific attributes in TLP, then communication efficiency is improved, but deviation from PCIe standard occurs

Engineering Contradiction:
Improvecommunication efficiencyVSAvoidPCIe standard compatibility
Core Design Contradiction:
ProductivityVSAdaptability or versatility

Solution Approach 1:

The patent makes the attribute extension mechanism universal by using reserved fields that can be optionally populated, allowing the same TLP structure to serve both standard PCIe communication and enhanced attribute-based optimization across different implementations

Inventive Principle:
Principle #6Universality (Multi-functionality)

Solution Approach 2:

The patent applies partial action by selectively adding attribute information only where needed (using optional fields), rather than fundamentally changing the entire TLP structure, thus providing efficiency improvements without forcing full adoption across all PCIe implementations

Inventive Principle:
Principle #16Partial or excessive action

3Productivity

If PCIe endpoint encodes transaction-specific attributes in TLP prefix, then host transaction performance is optimized, but TLP parsing complexity increases

Engineering Contradiction:
Improvehost transaction performanceVSAvoidTLP parsing complexity
Core Design Contradiction:
ProductivityVSDevice complexity

Solution Approach 1:

The patent applies preliminary action by encoding all necessary transaction attributes in advance within the TLP prefix during packet generation, allowing the host to extract performance-critical information without complex real-time analysis of the transaction context

Inventive Principle:
Principle #10Preliminary action

Data Source

PatentEP3311295B1Communicating transaction-specific attributes in a peripheral component interconnect express (PCIE) system
Publication Date: 2019.12.11 QUALCOMM INC
  • EP3311295B1 patent drawingFigure 1
  • EP3311295B1 patent drawingFigure 2A~2C
  • EP3311295B1 patent drawingFigure 3

AI summary

A PCIe system includes a host system (304) and at least one PCIe endpoint (302). The PCIe endpoint is configured to determine one or more transaction-specific attributes that can improve efficiency and performance of a predefined host transaction. The PCIe endpoint encodes the transaction-specific attributes in a transaction layer packet (TLP) prefix of at least one PCIe TLP and provides the PCIe TLP to the host system. A PCIe root complex (316) in the host system is configured to detect and extract the transaction-specific attributes from the TLP prefix of the PCIe TLP received from the PCIe endpoint. By communicating the transaction-specific attributes in the TLP prefix of the PCIe TLP, it is possible to improve efficiency and performance of the PCIe system without violating the existing PCIe standard.