Patent ID: 9342472
Filing Date: 2016-05-17
CPC Classification: G06F

Claim Text:
1. A Physical Region Descriptor (PRD) pre-fetch method for a Direct Memory Access (DMA) unit, comprising: determining whether a DMA request comprises a DMA out request or a DMA in request; monitoring a queue by detecting a data storage state of the queue to determine whether to pre-fetch a PRD entry when the DMA request is received, wherein the queue is used to store data corresponding to the DMA request; when the queue is full and cannot hold any more data from a memory for the DMA out request or the queue is empty and cannot give any more data to the memory for the DMA in request, pre-fetching at least one PRD entry from a PRD table and storing the PRD entry to a cache memory; and once the queue is not full for the DMA out request or the queue is not empty for the DMA in request, stopping pre-fetching the PRD entry from the PRD table; and reading a current PRD entry from the cache memory and performing a DMA out transaction according to the current PRD entry once the queue is not full for the DMA out request, or performing a DMA in transaction according to the current PRD entry once the queue is not empty for the DMA in request.