DMA Circuit Resource Usage Counter Arbitration
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Solution Overview
Problem
In multi-core microcontrollers, shared direct memory access (DMA) resources can lead to interference between applications with real-time and security requirements, causing undesired side effects due to uncontrolled access and bandwidth utilization, which existing arbitration schemes fail to adequately address, resulting in potential deadline misses and poor hardware utilization.
Innovation Solution
A direct memory access circuit with resource usage counters and an arbiter that evaluates execution time to assign, delay, or deny DMA access based on predefined thresholds and priority schemes, ensuring each application adheres to its allocated bandwidth, preventing interference and optimizing resource utilization.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a shared DMA resource is used for multiple applications, then hardware utilization is improved, but interference between applications occurs causing undesired side effects
Solution Approach 1:
The patent segments the shared DMA resource into multiple groups of DMA channels, where each group is assigned to a specific application. This segmentation allows multiple applications to share the DMA resource while maintaining isolation through group-based access control and resource usage counters that track and limit each application's DMA usage.
2Productivity
If DMA access is allowed without restriction to maximize throughput, then productivity is improved, but bandwidth overruns and buffer overflows occur
Solution Approach 1:
The patent implements preliminary action by configuring resource usage counters and thresholds before DMA operations begin. The arbiter continuously monitors these counters and preemptively denies DMA access when thresholds are approached, preventing buffer overflows and bandwidth overruns before they occur rather than reacting after the problem arises.
3Reliability
If an arbitration scheme is implemented to control DMA access, then application isolation is improved, but device complexity increases
Solution Approach 1:
The patent applies self-service by implementing resource usage counters that automatically track each application's DMA usage and trigger arbitration decisions without requiring complex external control logic. The counters autonomously compare usage against predefined thresholds and signal the arbiter, simplifying the overall arbitration mechanism while maintaining reliable application isolation.
Data Source
AI summary
A direct memory access (DMA) circuit is provided. The DMA circuit may include a plurality of groups of direct memory access channels, wherein each of the groups includes at least one DMA channel and a resource usage counter configured to count an execution time in which one of the DMA channels of the group is executed, and an arbiter configured to evaluate a value of the resource usage counter of a group upon a request for execution time by one of the DMA channels of the group, and, taking into account a result of the evaluation, to assign, delay assignment, or deny execution time for using the direct memory access to one of the groups.