SoC Access Control via Identification Comparison and Response Selection
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Solution Overview
Problem
Conventional access control systems in system-on-chip (SoC) designs face challenges in managing concurrent access to shared resources by functional circuits executing safety and non-safety operations, leading to operational failures and increased design complexity due to the need for priority assignment and handshake signal communication.
Innovation Solution
An access control system comprising a comparison circuit, a processing circuit, and a selection circuit that receives identification data, compares it with reference data, generates a select signal, and selects between error-injected and original response data to provide accurate responses to functional circuits, eliminating the need for priority assignment and handshake signals, allowing concurrent access.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If priority assignment and handshake signals are used to control access to shared resource, then operational failure is prevented, but design complexity and programming overhead increase significantly
Solution Approach 1:
The access control system is segmented into distinct functional blocks: a comparison circuit that identifies functional circuits based on identification data, a processing circuit that handles error injection, and a selection circuit that routes responses. This segmentation allows each component to perform a specific function independently, reducing overall system complexity while maintaining reliability through structured organization.
Solution Approach 2:
The comparison circuit acts as an intermediary that receives identification data from functional circuits, compares it with reference data, and generates select signals without requiring complex handshake protocols. This intermediary approach simplifies the access control mechanism by using data comparison rather than complex priority arbitration and handshake signaling.
2Productivity
If error-injected data is provided to functional circuits executing non-safety operations, then safety operations can execute concurrently, but operational failure occurs in non-safety operations
Solution Approach 1:
The system applies local quality by providing different data quality to different functional circuits based on their operation type. Safety operations receive error-free data through one data path, while non-safety operations receive error-injected data through another path. The comparison circuit and selection circuit enable this differentiated treatment by routing responses based on whether the functional circuit requires high reliability or can tolerate errors for testing purposes.
Solution Approach 2:
The system changes the parameter of data quality (error-free vs. error-injected) based on the type of operation being performed. The processing circuit modifies the error state of data dynamically, allowing concurrent execution of safety operations with high reliability and non-safety operations with error injection for testing, without interference between the two operation types.
3Reliability
If lower priority functional circuits halt access operations, then concurrent access conflicts are avoided, but programming overhead increases
Solution Approach 1:
The functional circuits perform self-identification by providing their own identification data to the comparison circuit. The comparison circuit automatically compares this identification data with reference data and generates the appropriate select signal without requiring external control or halting of operations. This self-service mechanism eliminates the need for priority assignment and handshake signals, reducing programming overhead while preventing access conflicts.
Data Source
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AI summary
An access control system controls access to a shared resource for various functional circuits. The access control system can include a comparison circuit, a processing circuit, and a selection circuit. The comparison circuit receives identification data associated with a functional circuit based on a transaction initiated by the functional circuit, and compares the identification data and reference data to generate a select signal. The processing circuit receives error data and response data outputted by the shared resource based on an execution of the transaction, and generates another response data. The selection circuit selects and outputs, based on the select signal, one of the response data outputted by the shared resource and the response data generated by the processing circuit as a transaction response that is to be provided to the functional circuit.