topic PCIe 2lane Driver support for i.MX 8QM. in i.MX Processors

PCIe 2lane Driver support for i.MX 8QM.

simon_ko — Mon, 09 Jan 2023 09:34:29 GMT

i.MX 8QM H/W supports PCIe dual lane.
However, it seems that only 1 lane is supported in the Linux driver.

In /Documentation/devicetree/bindings/pci/fsl,imx6q-pcie.yaml, num-lanes is only described as "const: 1".
And do not check "num-lanes" property in pci-imx6.c.

Is what I checked correct?

Re: PCIe 2lane Driver support for i.MX 8QM.

jimmychan — Tue, 10 Jan 2023 02:21:31 GMT

i.MX8QM has both PCIeA and PCIeB.

https://source.codeaurora.org/external/imx/linux-imx/tree/arch/arm64/boot/dts/freescale/imx8qm-ss-hsio.dtsi?h=imx_5.4.70_2.3.0

Re: PCIe 2lane Driver support for i.MX 8QM.

simon_ko — Tue, 10 Jan 2023 02:47:44 GMT

Thank you for answer.
I know i.MX 8QM has 2 PCIe Lanes.

Two PCIe can be used as PCIe x 2Lane or as 2 PCIe x 1Lane.

Current Driver only has 2 PCIe x 1Lane examples.
I have a question about how to use PCIe x 2Lane.

Re: PCIe 2lane Driver support for i.MX 8QM.

jimmychan — Wed, 11 Jan 2023 09:40:05 GMT

I cannot find the example. Let me check with the internal team.

Re: PCIe 2lane Driver support for i.MX 8QM.

simon_ko — Tue, 17 Jan 2023 00:25:16 GMT

In the link below, we confirmed the use of two PCIe Lanes.

https://github.com/nxp-imx/linux-imx/blob/lf-5.15.y/arch/arm64/boot/dts/freescale/imx8qm-pcieax2pciebx1.dts

thank you.