Buffer Descriptor Summary

Zynq UltraScale+ Device Technical Reference Manual (UG1085)

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2.4 English

Both the SRC and DST descriptors must be aligned to their size.

For efficiency, a DMA can prefetch a descriptor.

The DMA never prefetches across the 4 KB boundary.

The circular descriptor should always have at least one link-list element.

Descriptors are not updated back to the memory. For instance, once a SRC/DST buffer descriptor is used by the DMA for data transfer, no updating of any field of SRC or DST buffer descriptor occurs to signal completion of a buffer descriptor to the software.

A completion interrupt, along with status (interrupt accounting), is supported. The software can read the content of ZDMA_CH_IRQ_SRC_ACCT/ZDMA_CH_IRQ_DST_ACCT to find the number of buffer descriptors processed.