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Ixiasoft
Visible to Intel only — GUID: mwh1416946785073
Ixiasoft
6.11. Using DMA Devices
In the HAL DMA device model, there are two categories of DMA transactions: transmit and receive. The HAL provides two device drivers to implement transmit channels and receive channels. A transmit channel takes data in a source buffer and transmits it to a destination device. A receive channel receives data from a device and deposits it in a destination buffer. Depending on the implementation of the underlying hardware, software might have access to only one of these two endpoints.
Copying data from memory to memory involves both receive and transmit DMA channels simultaneously.
The API for access to DMA devices is defined in sys/alt_dma.h.
For more information about the use of these functions, refer to the HAL API Reference section.
DMA devices operate on the contents of physical memory, therefore when reading and writing data you must consider cache interactions.
For more information about cache memory, refer to the Cache and Tightly-Coupled Memory section.