PCIe on i.MX7

[annah]

We are having issues getting PCIe to work on our i.MX7 board. We were told that PCIe is supported for i.MX7-sabresd in rel_imx_4.1.15_1.1.0_ga release, but we are also unable to get it to work on the SabreSD board (Rev. B). Is this a known issue with this board revision? Which revision was used to test PCIe?

This is the error:

imx6q-pcie 33800000.pcie: phy link never came up

imx6q-pcie 33800000.pcie: failed to initialize host

imx6q-pcie: probe of 33800000.pcie failed with error -22

To build the rel_imx_4.1.15_1.1.0_ga kernel, I am using the imx_v7_defconfig and enabling the configs described in the i.MX Linux Reference Manual:

                CONFIG_PCI=y

                CONFIG_PCI_MSI=y

                CONFIG_PCI_IMX6=y

Thank you,

Anna

[joepan]

Hi all，

    It need add R597 and R598 ? The RevD is mark DNP.

[gfine]

Hi Anna (annah),

How are you connecting to the 7D? The connector, on the 7D, is a mini PCIe.

The -22 error is a generic error saying that PCIe is active but it can not recognize the adapter in the slot, and can not enumerate it.

You are using either a mini PCie adapter or a mini PCIe to Full Size PCIe adapter with a PCIe card of some sort. The problem is the mini to Full PCIe adapter only supports PCIe x1 connections.  PCIe x4, x8, or x16 connections are not supported.  So if you are using the mini to Full adapter and the card is anything other than a PCIe x1 connection it will fail to enumerate, and give a -22 error.

In my case I have an Intel i210 NIC card.  It has x1 compatibility. It works and enumerates with lspci.   Other NICs, like the Intel x550, uses PCIe x4 connection and fail to enumerate.

Cheers,

Glen

[gfine]

annah‌

Any change in status?

Cheers,

Glen

[annah]

Hi Glen,

Thanks for your input. We needed to add resistors (R634 and R635 on Sabre schematic RevD) to PCIE_REFCLK_OUT_P/N for PCIe to function correctly.

[weidong_sun]

Hello Anna,

      On how to PCIe interface, we have a detailed document to describ it, Even if the document is for PCIe on i.MX6Q, it's operation and usage are very samiliar to that of i.MX7D, so you can refer to it. see the link , please!

i.MX6Q PCIe EP/RC Validation System

Hope it can help you!

Regards,

Weidong