PCIe on i.mx8: Phy link never came up

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PCIe on i.mx8: Phy link never came up

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kunal_003
Contributor III

Hi all,

 

We are trying to use PCIe on our custom i.MX8M Plus based design. Unlike EVK that has M.2 connector, we are using mini PCIe connector. We are not able to get RC device in lspci. Below are the dmesg log related to PCI:

[    0.089490] PCI: CLS 0 bytes, default 64
[    1.390478] ehci-pci: EHCI PCI platform driver
[    1.406623] ohci-pci: OHCI PCI platform driver
[    2.652819] imx6q-pcie 33800000.pcie: 33800000.pcie supply epdev_on not found, using dummy regulator
[    2.662252] imx6q-pcie 33800000.pcie: PLL REF_CLK is used!.
[    2.668456] imx6q-pcie 33800000.pcie: PCIe PHY PLL clock is locked.
[    2.702156] imx6q-pcie 33800000.pcie: PCIe PLL locked after 0 us.
[    2.708478] imx6q-pcie 33800000.pcie: host bridge /pcie@33800000 ranges:
[    2.718820] imx6q-pcie 33800000.pcie:   No bus range found for /pcie@33800000, using [bus 00-ff]
[    2.731283] imx6q-pcie 33800000.pcie:    IO 0x1ff80000..0x1ff8ffff -> 0x00000000
[    2.742337] imx6q-pcie 33800000.pcie:   MEM 0x18000000..0x1fefffff -> 0x18000000
[    3.754072] imx6q-pcie 33800000.pcie: Phy link never came up
[    3.760970] imx6q-pcie 33800000.pcie: failed to initialize host
[    3.769652] imx6q-pcie 33800000.pcie: unable to add pcie port.

 

Also the schematic of PCI section is as below:

Screenshot (25).png

We are using internal clock, so taken reference from EVK PCIe nodes. With some modifications, below is the device tree node:

        pinctrl_pcie: pciegrp {
                fsl,pins = <
/*                      MX8MP_IOMUXC_I2C4_SCL__PCIE_CLKREQ_B            0x61  open drain, pull up */
                        MX8MP_IOMUXC_SAI1_MCLK__GPIO4_IO20              0x41
                        MX8MP_IOMUXC_SAI1_TXD6__GPIO4_IO18              0x41
                >;
        };

&pcie{
        pinctrl-names = "default";
        pinctrl-0 = <&pinctrl_pcie>;
        disable-gpio = <&gpio4 20 GPIO_ACTIVE_LOW>;
        reset-gpio = <&gpio4 18 GPIO_ACTIVE_LOW>;
        ext_osc = <0>;
        clocks = <&clk IMX8MP_CLK_HSIO_AXI_DIV>,
                 <&clk IMX8MP_CLK_PCIE_AUX>,
                 <&clk IMX8MP_CLK_PCIE_PHY>,
                 <&clk IMX8MP_CLK_PCIE_ROOT>;
        clock-names = "pcie", "pcie_aux", "pcie_phy", "pcie_bus";
        assigned-clocks = <&clk IMX8MP_CLK_HSIO_AXI_SRC>,
                          <&clk IMX8MP_CLK_PCIE_AUX>;
        assigned-clock-parents = <&clk IMX8MP_SYS_PLL2_500M>,
                                 <&clk IMX8MP_SYS_PLL2_50M>;
        status = "okay";
};

&pcie_phy{
        ext_osc = <0>;
        status = "okay";
};

&pcie_ep{
        status = "disabled";
        pinctrl-names = "default";
        pinctrl-0 = <&pinctrl_pcie>;
        ext_osc = <1>;
        clocks = <&clk IMX8MP_CLK_HSIO_AXI_DIV>,
                 <&clk IMX8MP_CLK_PCIE_AUX>,
                 <&clk IMX8MP_CLK_PCIE_PHY>,
                 <&clk IMX8MP_CLK_PCIE_ROOT>;
        clock-names = "pcie", "pcie_aux", "pcie_phy", "pcie_bus";
        assigned-clocks = <&clk IMX8MP_CLK_HSIO_AXI_SRC>,
                          <&clk IMX8MP_CLK_PCIE_AUX>;
        assigned-clock-parents = <&clk IMX8MP_SYS_PLL2_500M>,
                                 <&clk IMX8MP_SYS_PLL2_50M>;
};

 

For now we are validating the hardware design as per the hardware design guide. Please help with some pointers on troubleshooting. Thanks in advance.

 

Regards,

Kunal

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2 Replies

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igorpadykov
NXP TechSupport
NXP TechSupport

Hi Kunal

 

one can look at below example with similar configuration, also recommended to try several pcie cards:

https://github.com/boundarydevices/linux-imx6/blob/boundary-imx_5.4.x_2.3.0/arch/arm64/boot/dts/free...

 

Best regards
igor

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kunal_003
Contributor III

Hi @igorpadykov,

 

PCIe is working for us now. It was an issue with our h/w or the module. With another setup it is working. We can close this ticket now.

 

Thank you for your response.

 

Regards,

Kunal

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