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Altera_Forum
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12 years ago

Handle DMA Page address received at the FPGA end during DMA transfer

Scatter Gather DMA transfer of 461KB is initiated from the Host PC to the ARRIA2GX FPGA using Jungo Driver. During the transfer apart from the actual data sent as input data , extra data which ...
Altera_Forum's avatar
Altera_Forum
Icon for Honored Contributor rankHonored Contributor
12 years ago

We are using Chain of Descriptors.

Explanation: Once the driver allocates a buffer of 461KBytes of data, the Operating system allocates pages (of 4KBytes in size). So 461KBytes of data is allocated with (461KBytes/4KBytes) number of pages/descriptors. the data size wont exceed 4 KB/descriptor (It can hold less than 4KBytes).

The data packet are received correctly with no mismatches but along with the data packets I get the extra packet as mentioned in the earlier post.