i.MX ProcessorsのトピックIMX8MQ pcie failed for large size data

IMX8MQ pcie failed for large size data

mcggoal — Wed, 29 Jul 2020 09:37:41 GMT

Hi,

I am trying to connect IMX8MQ with intel FPGA thru PCIE+DMA, IMX8 as RP and FPGA as EP.

I've succeed to read/write a 4KB size data from/to RP thru FPGA's DMA, but it failed when changed to the larger size, e.g 16KB.

When I captured signals on DMA, it was founded that only 1 cycle of read operation happened, then DMA hang up with BUSY status, and bytes_left is 16,384.

Anyone who knows why ? Sincerely hope for your help!

Re: IMX8MQ pcie failed for large size data

igorpadykov — Thu, 30 Jul 2020 00:52:14 GMT

Hi Chenguang

what bsp used in the case, could you try latest

Embedded Linux for i.MX Applications Processors | NXP

linux-imx - i.MX Linux kernel

Best regards
igor
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Re: IMX8MQ pcie failed for large size data

mcggoal — Thu, 30 Jul 2020 01:38:42 GMT

Hi, igor

Thanks for reply.

I am now using 4.19.35, IMX8MQ EVK, it is almost the newest.

One point to be confirmed, I found below description in processor reference manual:

Does it mean the DMA operation must be splited into 4K pieces for a large size data ?

Re: IMX8MQ pcie failed for large size data

igorpadykov — Thu, 30 Jul 2020 04:09:30 GMT

Hi Chenguang

sorry 4.19.35 is not newest, please check latest on

Embedded Linux for i.MX Applications Processors | NXP

linux-imx - i.MX Linux kernel

Best regards
igor

Re: IMX8MQ pcie failed for large size data

mcggoal — Thu, 30 Jul 2020 08:33:15 GMT

Pls, It is a big effort to change kernel.
And I am sure that will not work.