topic SDMA transfer to/from memory shared with PCIe root in i.MX Processors

SDMA transfer to/from memory shared with PCIe root

FredrikMoller — Thu, 16 Oct 2014 16:51:56 GMT

I have an imx6 set up as PCIe endpoint where the lower 16MB of DDR memory (address 0x10000000-0x11000000) is shared with the PCIe root on the other side of the PCIe link.

I want to use SDMA on the imx6 to copy to/from this memory. Is this possible?

The reason I ask is because of this discussion PCIe DMA problems with i.MX6 which seems to imply that that is not the case.

Re: SDMA transfer to/from memory shared with PCIe root

igorpadykov — Thu, 16 Oct 2014 23:51:34 GMT

Hi Frederik

yes correct, SDMA can not be used with PCIe module.

Also it may be useful to look at

i.MX6Q PCIe EP/RC Validation System

Best regards

igor

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Re: SDMA transfer to/from memory shared with PCIe root

FredrikMoller — Fri, 17 Oct 2014 08:15:49 GMT

Thanks a lot!

Btw, you don't happen to know where this limitation is documented in the reference manual for imx6?

Regards,

Fredrik

Re: SDMA transfer to/from memory shared with PCIe root

igorpadykov — Fri, 17 Oct 2014 08:20:55 GMT

There are no direct references, however

for example there is no PCIe in

Table A-1. SDMA Scripts Overview IMX6DQRM

~igor