The NXP i.MX8QXP CPU has two 10/100/1000 Ethernet MACs.

On the ConnectCore 8X SBC Pro:

  • Ethernet1 port is connected to a 10/100/1000 Atheros AR8031 PHY.

  • Ethernet2 port is connected to a 10/100/1000 Atheros AR8031 PHY.

Kernel configuration

You can manage the Ethernet driver and PHY Device support through the following kernel configuration options:

  • FEC Ethernet controller (of ColdFire and some i.MX CPUs) (CONFIG_FEC)

  • PHY device support for AT803x (CONFIG_AT803X_PHY)

These options are enabled as built-in on the default ConnectCore 8X kernel configuration file.

Kernel driver

The driver for the Ethernet interface is located at:

File Description

drivers/net/ethernet/freescale/fec_main.c

i.MX FEC driver

drivers/net/phy/at803x.c

Driver for Atheros 8031 PHY

Device tree bindings and customization

The i.MX8QXP Ethernet interface device tree binding is documented at Documentation/devicetree/bindings/net/fsl,fec.yaml. The Ethernet interfaces are defined in the i.MX8QXP CPU and ConnectCore 8X SBC Pro device tree files.

Example: FEC1 & FEC2 on ConnectCore 8X SBC Pro

Definition of the FECs

i.MX8QXP device tree
fec1: ethernet@5b040000 {
	reg = <0x5b040000 0x10000>;
	interrupts = <GIC_SPI 258 IRQ_TYPE_LEVEL_HIGH>,
		     <GIC_SPI 256 IRQ_TYPE_LEVEL_HIGH>,
		     <GIC_SPI 257 IRQ_TYPE_LEVEL_HIGH>,
		     <GIC_SPI 259 IRQ_TYPE_LEVEL_HIGH>;
	clocks = <&enet0_lpcg 4>,
		 <&enet0_lpcg 2>,
		 <&enet0_lpcg 3>,
		 <&enet0_lpcg 0>,
		 <&enet0_lpcg 1>;
	clock-names = "ipg", "ahb", "enet_clk_ref", "ptp", "enet_2x_txclk";
	assigned-clocks = <&clk IMX_SC_R_ENET_0 IMX_SC_PM_CLK_PER>,
			  <&clk IMX_SC_R_ENET_0 IMX_SC_C_CLKDIV>;
	assigned-clock-rates = <250000000>, <125000000>;
	fsl,num-tx-queues=<3>;
	fsl,num-rx-queues=<3>;
	power-domains = <&pd IMX_SC_R_ENET_0>;
	status = "disabled";
};

fec2: ethernet@5b050000 {
	reg = <0x5b050000 0x10000>;
	interrupts = <GIC_SPI 262 IRQ_TYPE_LEVEL_HIGH>,
			<GIC_SPI 260 IRQ_TYPE_LEVEL_HIGH>,
			<GIC_SPI 261 IRQ_TYPE_LEVEL_HIGH>,
			<GIC_SPI 263 IRQ_TYPE_LEVEL_HIGH>;
	clocks = <&enet1_lpcg 4>,
		 <&enet1_lpcg 2>,
		 <&enet1_lpcg 3>,
		 <&enet1_lpcg 0>,
		 <&enet1_lpcg 1>;
	clock-names = "ipg", "ahb", "enet_clk_ref", "ptp", "enet_2x_txclk";
	assigned-clocks = <&clk IMX_SC_R_ENET_1 IMX_SC_PM_CLK_PER>,
			  <&clk IMX_SC_R_ENET_1 IMX_SC_C_CLKDIV>;
	assigned-clock-rates = <250000000>, <125000000>;
	fsl,num-tx-queues=<3>;
	fsl,num-rx-queues=<3>;
	power-domains = <&pd IMX_SC_R_ENET_1>;
	status = "disabled";
};

IOMUX configuration

ConnectCore 8X SBC Pro device tree
/* FEC shared MDIO bus */
pinctrl_fec_mdio: fecmdiogrp {
	fsl,pins = <
		IMX8QXP_ENET0_MDC_CONN_ENET0_MDC		0x06000020
		IMX8QXP_ENET0_MDIO_CONN_ENET0_MDIO		0x06000020
	>;
};

pinctrl_fec1_gpio: fec1gpiogrp {
	fsl,pins = <
		/* PHY reset */
		IMX8QXP_QSPI0B_DATA0_LSIO_GPIO3_IO18	0x06000021
		/* PHY interrupt */
		IMX8QXP_MIPI_DSI0_GPIO0_01_LSIO_GPIO1_IO28	0x06000021
	>;
};

pinctrl_fec1_gpio_sleep: fec1gpiosleepgrp {
	fsl,pins = <
		/* PHY reset */
		IMX8QXP_QSPI0B_DATA0_LSIO_GPIO3_IO18	0x06000041
	>;
};

pinctrl_fec1: fec1grp {
	fsl,pins = <
		/*
		 * The SCFW of B0 defaults ENET0 domains to 2.5V:
		 * - VDD_ENET0_1P8_2P5_3P3
		 * - VDD_ENET0_VSELECT_1P8_2P5_3P3
		 * Turn the domains back to 1.8/3.3V detector
		 */
		IMX8QXP_COMP_CTL_GPIO_1V8_3V3_ENET_ENETB0_PAD	0x000014a0
		IMX8QXP_COMP_CTL_GPIO_1V8_3V3_ENET_ENETB1_PAD	0x000014a0

		IMX8QXP_ENET0_RGMII_TX_CTL_CONN_ENET0_RGMII_TX_CTL	0x00000061
		IMX8QXP_ENET0_RGMII_TXC_CONN_ENET0_RGMII_TXC	0x00000061
		IMX8QXP_ENET0_RGMII_TXD0_CONN_ENET0_RGMII_TXD0	0x00000061
		IMX8QXP_ENET0_RGMII_TXD1_CONN_ENET0_RGMII_TXD1	0x00000061
		IMX8QXP_ENET0_RGMII_TXD2_CONN_ENET0_RGMII_TXD2	0x00000061
		IMX8QXP_ENET0_RGMII_TXD3_CONN_ENET0_RGMII_TXD3	0x00000061
		IMX8QXP_ENET0_RGMII_RXC_CONN_ENET0_RGMII_RXC	0x00000061
		IMX8QXP_ENET0_RGMII_RX_CTL_CONN_ENET0_RGMII_RX_CTL	0x00000061
		IMX8QXP_ENET0_RGMII_RXD0_CONN_ENET0_RGMII_RXD0	0x00000061
		IMX8QXP_ENET0_RGMII_RXD1_CONN_ENET0_RGMII_RXD1	0x00000061
		IMX8QXP_ENET0_RGMII_RXD2_CONN_ENET0_RGMII_RXD2	0x00000061
		IMX8QXP_ENET0_RGMII_RXD3_CONN_ENET0_RGMII_RXD3	0x00000061
	>;
};

pinctrl_fec2_gpio: fec2gpiogrp {
	fsl,pins = <
		/* PHY reset */
		IMX8QXP_QSPI0B_DQS_LSIO_GPIO3_IO22		0x06000021
		/* PHY interrupt */
		IMX8QXP_MIPI_DSI1_GPIO0_01_LSIO_GPIO2_IO00	0x06000021
	>;
};

pinctrl_fec2_gpio_sleep: fec2gpiosleepgrp {
	fsl,pins = <
		/* PHY reset */
		IMX8QXP_QSPI0B_DQS_LSIO_GPIO3_IO22		0x06000041
	>;
};

pinctrl_fec2: fec2grp {
	fsl,pins = <
		/*
		 * The SCFW of B0 defaults ENET1 domain to 2.5V:
		 * - VDD_ESAI_SPDIF_1P8_2P5_3P3
		 * Turn the domain back to 1.8/3.3V detector
		 */
		IMX8QXP_COMP_CTL_GPIO_1V8_3V3_GPIORHB_PAD		0x000514a0

		IMX8QXP_ESAI0_SCKR_CONN_ENET1_RGMII_TX_CTL		0x00000060
		IMX8QXP_ESAI0_FSR_CONN_ENET1_RGMII_TXC		0x00000060
		IMX8QXP_ESAI0_TX4_RX1_CONN_ENET1_RGMII_TXD0	0x00000060
		IMX8QXP_ESAI0_TX5_RX0_CONN_ENET1_RGMII_TXD1	0x00000060
		IMX8QXP_ESAI0_FST_CONN_ENET1_RGMII_TXD2		0x00000060
		IMX8QXP_ESAI0_SCKT_CONN_ENET1_RGMII_TXD3		0x00000060
		IMX8QXP_ESAI0_TX0_CONN_ENET1_RGMII_RXC		0x00000060
		IMX8QXP_SPDIF0_TX_CONN_ENET1_RGMII_RX_CTL		0x00000060
		IMX8QXP_SPDIF0_RX_CONN_ENET1_RGMII_RXD0		0x00000060
		IMX8QXP_ESAI0_TX3_RX2_CONN_ENET1_RGMII_RXD1	0x00000060
		IMX8QXP_ESAI0_TX2_RX3_CONN_ENET1_RGMII_RXD2	0x00000060
		IMX8QXP_ESAI0_TX1_CONN_ENET1_RGMII_RXD3		0x00000060
	>;
};

Ethernet enabling and PHY parameters

ConnectCore 8X SBC Pro device tree
&fec1 {
	pinctrl-names = "default", "sleep";
	pinctrl-0 = <&pinctrl_fec_mdio>,
		    <&pinctrl_fec1_gpio>,
		    <&pinctrl_fec1>;
	pinctrl-1 = <&pinctrl_fec1_gpio_sleep>;
	phy-mode = "rgmii-id";
	phy-handle = <&ethphy1>;
	digi,mdio-lt-supply = <&reg_1v8_ext>;
	phy-supply = <&reg_3v3_eth0>;
	phy-reset-gpios = <&lsio_gpio3 18 GPIO_ACTIVE_LOW>;
	phy-reset-duration = <1>;
	digi,phy-reset-in-suspend;
	fsl,magic-packet;
	status = "disabled";

	mdio {
		#address-cells = <1>;
		#size-cells = <0>;

		ethphy0: ethernet-phy@0 {
			compatible = "ethernet-phy-ieee802.3-c22";
			reg = <0>;
			at803x,eee-disabled;
			at803x,vddio-1p8v;
		};

		ethphy1: ethernet-phy@1 {
			compatible = "ethernet-phy-ieee802.3-c22";
			reg = <1>;
			at803x,eee-disabled;
			at803x,vddio-1p8v;
		};
	};
};

&fec2 {
	pinctrl-names = "default", "sleep";
	pinctrl-0 = <&pinctrl_fec2_gpio>,
		    <&pinctrl_fec2>;
	pinctrl-1 = <&pinctrl_fec2_gpio_sleep>;
	phy-mode = "rgmii-id";
	phy-handle = <&ethphy0>;
	digi,mdio-lt-supply = <&reg_1v8_ext>;
	phy-supply = <&reg_3v3_eth0>;
	phy-reset-gpios = <&lsio_gpio3 22 GPIO_ACTIVE_LOW>;
	phy-reset-duration = <1>;
	digi,phy-reset-in-suspend;
	fsl,magic-packet;
	status = "disabled";
};

MAC addresses

The MAC addresses of the i.MX8QXP Ethernet interfaces are programmed in the U-Boot environment (variables ethaddr and eth1addr) on the ConnectCore 8X eMMC. The MAC address of the first Ethernet interface is also printed on the module label. U-Boot writes the MAC addresses in the ethaddr and ethaddr1 environment variables into their respective device tree fec nodes under the local-mac-address property. For more information, see Environment variables.

Ethernet user space usage

In the Linux system, the Ethernet interfaces are known as ethX where X is a number, starting at 0, that indicates the interface index. The Ethernet (FEC) driver exposes device data through the sysfs at /sys/class/net/ethX. You can use NetworkManager to configure Ethernet settings such as IP and netmask.