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Altera_Forum's avatar
Altera_Forum
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12 years ago

Simple PCIe DMA

I guess I could try to find the appropriate documentation, but I'll cheat and ask here! I need to find which DMA block to ask our HW team to add to qsys in order to do burst PCIe transfers from...
Altera_Forum's avatar
Altera_Forum
Icon for Honored Contributor rankHonored Contributor
8 years ago

To answer myself 4 years later....

We set the Qsys avalon to PCIe bridge for 512 16k pages and allocate non-contiguous kernel buffers that don't cross 16k boundaries.

These can me mmap()ed into contiguous user addresses ('interesting' on windows!).

All the used entries point to a 'dummy' page 'just in case'.

Any Avalon master has to do burst transfers to generate reasonable sized TLP.

I ended up writing a suitable DMA controller.