Pcie dma transfer data

Autonomous Machines Jetson & Embedded Systems Jetson AGX Xavier
1

I’m doing a trial to do memory copy using pcie dma between two different processes A and B.
But cannot find any pcie relative dma operations API.
Is there a demo application to move data using PCIE API? And could you help share it ？

Thank you very much, nvidia.

3

Hi,

Are you planning to use DMA between two processes which are running on same CPU(i.e Tegra). DMA is used for data transfer between IO and System memory, you cannot use DMA to transfer between two processes.

Thanks,
Manikanta

4

So test on DMA transfering data between processes cannot be carried out, right?

Another question, i cannot find any related API to do dma_request.
Could you tell me where is it? how to instantiate DMA trasferring.
Any memory allocation related steps could be skipped, for I’m going to use scatterlist.

Thank you very much, nvidia.

5

Plus.
PCIe DMA transferring API.

6

Hi,

Normally PCIe endpoint implements DMA engine, so DMA transfer programming sequence will be endpoint implementer specific.
Refer to https://www.kernel.org/doc/Documentation/DMA-API-HOWTO.txt for dma memory allocation at Tegra side.

Thanks,
Manikanta