i.MX ProcessorsのトピックRe: PCIe RP Controller VS PCIe EP Controller

PCIe RP Controller VS PCIe EP Controller

shivam_jksel — Mon, 18 Mar 2024 14:39:43 GMT

Hi,

1) can you guide me to the file/code in linux kernel for the PCIe RP controller driver and also for PCIe EP controller driver?

2) how does a RC Controller driver differs from the EP controller driver?

3) what are the role/responsibility/functions of a RC and EP controllers?

I want to buy two IMX boards which can act as PCI HOST and PCIe EP, please suggest which boards will be fine . my use case is just to test out the complete basic PCIe end to end and how the EP RC talk to each other.

Re: PCIe RP Controller VS PCIe EP Controller

weidong_sun — Tue, 19 Mar 2024 03:50:33 GMT

Dear @shivam_jksel ,

1. About EVK boards.

--i.MX8MQ-EVK & i.MX8MM-EVK support PCIe GEN2, PCIe signals are connected to M.2 KEY E connector.

--i.MX8MP-EVK supports PCIe GEN3, also users can get PCIe signals on M.2 KEY E connectot.

you can evaluate above 3 boards.

2. About driver in linux kernel

Default configurations of Kernel have supported RC & EP driver.

3. device tree

For EP role, the dts for EP has been ready in device tree, on EP side, you should use it.

Thanks!

Regards,

weidong

Re: PCIe RP Controller VS PCIe EP Controller

shivam_jksel — Tue, 19 Mar 2024 05:38:34 GMT

@weidong_sun

1)
thanks for the name of the boards.

2)
the RC EP controller file structure in kernel is this, correct me if i am wrong:

pci_subsytem <--> pcie_designware_host.c <--> pci_imx6.c <---> ROOT PORT CONTROLLER

pci_subsytem <--> pcie_designware_ep.c <--> pci_imx6.c <---> END POINT CONTROLLER

3)
device tree for RC is different or same?

Regards,

Re: PCIe RP Controller VS PCIe EP Controller

weidong_sun — Tue, 19 Mar 2024 07:28:57 GMT

Dear @shivam_jksel .

>> Q2:

RC driver & EP roles are both supported in pci-imx6.c

static const struct of_device_id imx6_pcie_of_match[] = {
{ .compatible = "fsl,imx6q-pcie", .data = &drvdata[IMX6Q], },
{ .compatible = "fsl,imx6q-pcie-ep", .data = &drvdata[IMX6Q_EP], },
{ .compatible = "fsl,imx6sx-pcie", .data = &drvdata[IMX6SX], },
{ .compatible = "fsl,imx6sx-pcie-ep", .data = &drvdata[IMX6SX_EP], },
{ .compatible = "fsl,imx6qp-pcie", .data = &drvdata[IMX6QP], },
{ .compatible = "fsl,imx6qp-pcie-ep", .data = &drvdata[IMX6QP_EP], },
{ .compatible = "fsl,imx7d-pcie", .data = &drvdata[IMX7D], },
{ .compatible = "fsl,imx7d-pcie-ep", .data = &drvdata[IMX7D_EP], },
{ .compatible = "fsl,imx8mq-pcie", .data = &drvdata[IMX8MQ], },
{ .compatible = "fsl,imx8mq-pcie-ep", .data = &drvdata[IMX8MQ_EP], },
{ .compatible = "fsl,imx8mm-pcie", .data = &drvdata[IMX8MM], },
{ .compatible = "fsl,imx8mm-pcie-ep", .data = &drvdata[IMX8MM_EP], },
{ .compatible = "fsl,imx8mp-pcie", .data = &drvdata[IMX8MP], },
{ .compatible = "fsl,imx8mp-pcie-ep", .data = &drvdata[IMX8MP_EP], },
{ .compatible = "fsl,imx8qm-pcie", .data = &drvdata[IMX8QM], },
{ .compatible = "fsl,imx8qm-pcie-ep", .data = &drvdata[IMX8QM_EP], },
{ .compatible = "fsl,imx8qxp-pcie", .data = &drvdata[IMX8QXP], },
{ .compatible = "fsl,imx8qxp-pcie-ep", .data = &drvdata[IMX8QXP_EP], },
{},
};

Q3:

Different dts .

-imx8mq-evk.dts, pcie RC

-imx8mq-evk-pci-ep.dts, EP

Thanks!

Regards,

weidong