Bidirectional Link Multiplexing for On-Chip Communication Infrastructure
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Solution Overview
Problem
Existing communication infrastructures for data processing apparatuses face challenges in efficiently connecting multiple crossbar circuits using bidirectional links, particularly with multi-channel communication protocols, leading to increased wire routing complexity and protocol conversion costs, as well as deadlock issues due to the lack of visibility of masters or slaves in packetised on-chip communication approaches.
Innovation Solution
A communication infrastructure employing switching circuitry with a bidirectional link that multiplexes forward and reverse channels using control circuitry based on handshaking signals, reducing the number of connection lines required and avoiding protocol conversion, while maintaining the integrity of multi-channel communication protocols.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If separate bidirectional links are provided for each communication path between crossbars, then communication functionality is achieved, but wire routing complexity increases
Solution Approach 1:
The patent merges multiple separate bidirectional links into a single shared bidirectional link that carries multiple channels (address channel, write data channel, read data channel, and response channel) between crossbars. This consolidation reduces wire routing complexity while maintaining full communication functionality through channel multiplexing.
Solution Approach 2:
The single bidirectional link is designed to perform multiple functions by carrying different types of communication channels (address, write data, read data, response) in both forward and reverse directions. This multi-functional approach eliminates the need for separate dedicated links for each channel type.
2Adaptability or versatility
If protocol conversion is implemented to enable communication between crossbars, then interoperability is achieved, but cost and complexity increase
Solution Approach 1:
The patent employs the same multi-channel communication protocol (e.g., AXI protocol) on both sides of the bidirectional link, ensuring homogeneous protocol operation. This eliminates the need for protocol conversion circuits and associated complexity, as both crossbars communicate using identical protocol rules and channel structures.
3Adaptability or versatility
If packetised on-chip communication is used, then communication flexibility is improved, but deadlock issues arise due to lack of visibility of masters or slaves
Solution Approach 1:
The patent incorporates handshaking signals (valid signals and ready signals) for each channel that provide continuous feedback between master and slave interfaces. This feedback mechanism enables real-time visibility of communication state, allowing the system to detect and prevent deadlock conditions while maintaining packetised communication flexibility.
Data Source
AI summary
A communication infrastructure for a data processing apparatus, and a method of operation of such a communication infrastructure are provided. The communication infrastructure provides first and second switching circuits interconnected via a bidirectional link. Both of the switching circuits employ a multi-channel communication protocol, such that for each transaction a communication path is established from an initiating master interface to a target slave interface, with that communication path comprising m channels. The m channels comprise one or more forward channels from the initiating master interface to the target slave interface and one or more reverse channels from the target slave interface to the initiating master interface, and handshaking signals are associated with each of the m channels. The bidirectional link comprises n connection lines, where n is less than m, the bidirectional link supporting a first communication path from the first switching circuit to the second switching circuit and a second communication path in an opposite direction from the second switching circuit to the first switching circuit. Control circuitry is used to multiplex at least one forward channel of the first communication path and at least one reverse channel of the second communication path, with the multiplexing being performed in dependence on the handshaking signals associated with the channels to be multiplexed. This allows the 2m channels formed by the first and second communication paths to be provided by the n connection lines of the bidirectional link.