DMA (Direct Memory Access) data transmission method and apparatus

Abstract

Embodiments of the invention disclose a DMA (Direct Memory Access) data transmission method and apparatus, and solve the technical problem of directly influenced frame rate due to low DMA efficiency caused by the fact that the time of one frame of DMA is equal to the sum of linked list reading time, DDR image data reading time and PCI-E (PCI Express) image data sending time. The DMA data transmission method disclosed by the embodiments of the invention comprises: caching linked list data read from DDR to a preset linked list data cache region, and caching video data subjected to mode alignment processing through presetting and read from DDR to a preset video data cache region; and when the preset linked list data cache region is in a non-null state and the preset video data cache region meets a one-time burst transmission condition, sending the video data to the TX end of PCI-E in a preset mode.

Description

technical field [0001] The invention relates to the technical field of data processing, in particular to a DMA data transmission method and device. Background technique [0002] PCI-E (PCIExpress) is a new generation bus interface, usually connected with a data acquisition card, DMA (DirectMemoryAccess, direct memory access) transmission copies data from one address space to another. When the CPU initiates the transfer, the transfer itself is executed and completed by the DMA controller. A typical example is moving a block of external memory to a faster memory area inside the chip. Instead of stalling processor work, operations like this can be rescheduled to handle other work. DMA transfers are important for high-performance embedded system algorithms and networks. [0003] In existing PCI-E-based processor acquisition cards, linked-list DMA is used to transmit video data, and video data is usually processed by frame, that is, DMA is started once, and DMA ends when one f...

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Problems solved by technology

[0005] The embodiment of the present invention provides a DMA data transmission method and device, which solves the problem that the time for one frame of traditional DMA is equal to the sum of the time-consuming time for reading the linked list, the time-consuming for DDR reading image data, and the time-consuming for sending image data by PCI-E. The inefficiency of DMA is a technical problem that directly affects the frame rate of the video

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