topic Re: How to implement P2P on IMX8MP? in i.MX Processors

How to implement P2P on IMX8MP?

22721579 — Mon, 16 Dec 2024 08:15:18 GMT

Hello,

I would like to implement PCIe P2P transmission between the EP development board (configured with IMX8MP) and an NVMe SSD. Does the IMX8MP support P2P?

Are there any related reference materials available for learning?

Re: How to implement P2P on IMX8MP?

pengyong_zhang — Tue, 17 Dec 2024 07:22:06 GMT

Hi @22721579

I found an article written by one of our in-house experts that I hope will help you:

1:On 8MP EVK board, base board resistor R452 should be changed to 0ohm.
2:This patch only done for 8MP/8MM EVK board.

Be careful: this patch may impact previous 6/8 PCIE function.

After merge this patch, in uboot, run below cmd to make NVME work:

u-boot=>pci e /* init pcie bus and enum devices */
u-boot=>nvme scan /* nvme scan devices */
u-boot=>pci 1 /* show pcie device info */
u-boot=>nvme info /* show nvme devcie info */
u-boot=>fatinfo nvme 0:1 /* asssue nvme first part is FAT */

B.R

Re: How to implement P2P on IMX8MP?

22721579 — Thu, 19 Dec 2024 02:49:12 GMT

Thank you for your reply.

However, I am using the IMX8MP as an EP device, so I would like to know if the IMX8MP supports P2P in EP mode? If it does, how should it be configured? Thank you.

Re: How to implement P2P on IMX8MP?

pengyong_zhang — Fri, 20 Dec 2024 06:09:12 GMT

HI @22721579

i.MX 8MP does EP with other EP do P2P?

B.R

Re: How to implement P2P on IMX8MP?

22721579 — Tue, 24 Dec 2024 07:23:48 GMT

The reason I am seeking help is that I am unsure whether the i.MX 8MP supports P2P.

From my observation, the i.MX 8MP EP does not map prefetchable space on the BAR. I am wondering if it is possible to configure a segment of prefetchable space in the i.MX 6ULL driver for P2P read and write operations.

Re: How to implement P2P on IMX8MP?

pengyong_zhang — Wed, 25 Dec 2024 05:25:19 GMT

HI @22721579

We haven't done any tests like this, But i think if your PCIe switch support, i.MX8MP can support it.

B.R