Random DMA Mode Circuit for Address Translation Testing
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Solution Overview
Problem
Integrated circuit testing tools face challenges in generating thorough and stressful test cases for direct memory access translation, particularly in high-speed communication links between processors and graphics processing units, which is costly in terms of time and resources.
Innovation Solution
A random DMA mode circuit is introduced to index into a translation validation table, allowing for efficient testing of all DMA modes by providing a random input, using a multiplexer to select between runtime and random test inputs, thereby enabling comprehensive testing regardless of connected bus agents.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional testing methods are used to test all DMA modes, then comprehensive test coverage is achieved, but testing becomes extremely costly in time and resources
Solution Approach 1:
The patent creates a virtual representation of multiple bus agents through a random DMA mode circuit that can simulate different agent behaviors. Instead of physically connecting and testing each bus agent configuration, the circuit generates random DMA requests that copy the essential characteristics of various agents, enabling comprehensive testing of address translation logic without the resource burden of physical multi-agent configurations.
Solution Approach 2:
The patent changes the operational parameters of the testing system by introducing a random DMA mode that dynamically varies request parameters such as source ID, destination address, and transfer size. This allows the same physical test setup to evaluate multiple DMA modes and address translation scenarios by simply changing the random parameters generated during testing, rather than requiring separate test configurations for each mode.
2Reliability
If multiple bus agents are connected to test all DMA modes, then complete testing is achieved, but device complexity and setup requirements increase
Solution Approach 1:
The random DMA mode circuit serves multiple testing functions within a single device component. It can simulate various bus agent types, generate different DMA request patterns, and test multiple address translation modes all through one unified circuit implementation. This multi-functional approach eliminates the need for separate test equipment for each DMA mode or agent type.
Solution Approach 2:
The testing system uses itself to generate test stimuli through the random DMA mode circuit. Instead of requiring external test equipment or multiple physical agents to provide test inputs, the system's own address translation logic is challenged by randomly generated DMA requests produced within the same device, enabling self-testing capabilities that reduce external dependencies.
Data Source
AI summary
A circuit and method provide efficient stress testing of address translations in an integrated circuit such as a link processing unit. A random DMA mode (RDM) circuit provides a random input to index into a translation validation table (TVT) that is used to generate the real memory address. The RDM circuit allows testing all entries of the TVT, and thus all DMA modes, regardless of what bus agents are connected to the link processing unit. The RDM circuit may use a multiplexer to select between a runtime input and a random test input provided by the random bit generator. When the link processing unit is in a test mode a mode selection bit is asserted to select the random test input.