Ethernet device tree configuration

Applicable for STM32MP13x lines, STM32MP15x lines

1 Article purpose[edit]

This article explains how to configure the Ethernet when it is assigned to the Linux® OS. In that case, it is controlled by the Ethernet framework.

The configuration is performed using the device tree mechanism that provides a hardware description of the Ethernet peripheral, used by the STM32 DWMAC driver.

2 DT bindings documentation[edit]

The Ethernet is a multifunction device.

Each function is represented by a separate binding document:

  • "Generic" Ethernet device tree bindings [1]
  • specific STM32 ETH device tree bindings[2]

3 DT configuration[edit]

This hardware description is a combination of the STM32 microprocessor device tree files (.dtsi extension) and board device tree files (.dts extension). See the Device tree for an explanation of the device tree file split.

3.1 DT configuration (STM32 level)[edit]

Ethernet peripheral nodes are located in

  • for STM32MP13x lines Warning.png in stm32mp131.dtsi [3] file,
  • for STM32MP15x lines More info.png in stm32mp151.dtsi [4] file,

In this file, the status must be set to disabled and some required properties such as:

  • Physical base address and size of the device register map
  • STM32 DWMAC interrupts
  • stmmaceth clock and Rx, Tx clocks

This is a set of properties that may not vary for a given STM32MP device, such as: register addresses, interrupts, clocks, ...

ethernet0: ethernet@5800a000 {
	compatible = "st,stm32mp1-dwmac", "snps,dwmac-4.20a";
	reg = <0x5800a000 0x2000>;
	reg-names = "stmmaceth";
                              <&exti 70 IRQ_TYPE_LEVEL_HIGH>;
        interrupts-extended = <&intc GIC_SPI 61 IRQ_TYPE_LEVEL_HIGH>,
        interrupt-names = "macirq",
                          "eth_wake_irq";
	clock-names = "stmmaceth",
		      "mac-clk-tx",
		      "mac-clk-rx",
		      "eth-ck",
		      "ethstp";
	clocks = <&rcc ETHMAC>,
		 <&rcc ETHTX>,
		 <&rcc ETHRX>,
		 <&rcc ETHCK_K>,
		 <&rcc ETHSTP>;
	st,syscon = <&syscfg 0x4>;
	snps,mixed-burst;
	snps,pbl = <2>;
        snps,en-tx-lpi-clockgating;
	snps,axi-config = <&stmmac_axi_config_0>;
	snps,tso;
	power-domains = <&pd_core>;
	status = "disabled";
};

The required and optional properties are fully described in the bindings files.

Warning white.png Warning
This device tree part is related to STM32 microprocessors. It must be kept as is, without being modified by the end-user.

3.2 Ethernet DT configuration (board level)[edit]

Warning white.png Warning
These DT are same between U-Boot and kernel OS

The device tree board file (.dts) contains all hardware configurations related to board design. The DT node ("ethernet") should be updated to:

  • Enable the Ethernet block by setting status = "okay".
  • Configure the pins in use via pinctrl, through pinctrl-0 (default pins), pinctrl-1 (sleep pins) and pinctrl-names.
  • Configure Ethernet interface used phy-mode = "rgmii"., (rmii, mii, gmii).
  • Configure Ethernet max speed max-speed = <1000>"..
&ethernet0 {
	status = "okay";
	pinctrl-0 = <&ethernet0_rgmii_pins_a>;
	pinctrl-1 = <&ethernet0_rgmii_pins_sleep_a>;
	pinctrl-names = "default", "sleep";
	phy-mode = "rgmii";
	max-speed = <1000>;
	phy-handle = <&phy0>;

	mdio0 {
		#address-cells = <1>;
		#size-cells = <0>;
		compatible = "snps,dwmac-mdio";
		phy0: ethernet-phy@1 {
			reg = <1>;
		};
	};
};

3.3 DT configuration examples at board level[edit]

The example below shows how to configure and enable an Ethernet instance

&ethernet0 {
   status = "okay";                             /* enable ethernet0 */ 
   pinctrl-0 = <&ethernet0_rmii_pins_a>;        /* configure pinctrl modes for ethernet0 */
   pinctrl-1 = <&ethernet0_rmii_pins_sleep_a>;  /* configure ethernet0_rmii_pins_sleep_a as sleep pinctrl configuration for ethernet0 */
   pinctrl-names = "default", "sleep";
   phy-mode = "rmii";                           /* configure ethernet phy mode for ethernet0 */
   max-speed = <100>;                           /* configure ethernet max speed for ethernet0 */
   phy-handle = <&phy0>;
   
   mdio0 {
       #address-cells = <1>;
       #size-cells = <0>;
       compatible = "snps,dwmac-mdio";
       phy0: ethernet-phy@1 {
           reg = <1>;                           /* configure ethernet phy @ for ethernet0 */
       };
   };
};

How to configure Ethernet for :

3.3.1 RMII with Crystal on PHY (Reference clock (standard RMII clock name) is provided by a Phy Crystal)[edit]

   &ethernet0 {
       status = "okay";
       pinctrl-0 = <&ethernet0_rmii_pins_a>;
       pinctrl-1 = <&ethernet0_rmii_pins_sleep_a>;
       pinctrl-names = "default", "sleep";
       phy-mode = "rmii";
       max-speed = <100>;
       phy-handle = <&phy0>;
       mdio0 {
               #address-cells = <1>;
               #size-cells = <0>;
               compatible = "snps,dwmac-mdio";
               phy0: ethernet-phy@0 {
                       reg = <0>;
               };
       };
   };

3.3.2 RMII with 25MHz on ETH_CLK (no PHY Crystal), REF_CLK from PHY (Reference clock (standard RMII clock name) is provided by a PHY)[edit]

   &ethernet0 {
       status = "okay";
       pinctrl-0 = <&ethernet0_rmii_pins_a>;
       pinctrl-1 = <&ethernet0_rmii_pins_sleep_a>;
       pinctrl-names = "default", "sleep";
       phy-mode = "rmii";
       max-speed = <100>;
       phy-handle = <&phy0>;
       mdio0 {
               #address-cells = <1>;
               #size-cells = <0>;
               compatible = "snps,dwmac-mdio";
               phy0: ethernet-phy@0 {
                       reg = <0>;
               };
       };
   };

+ update stm32mp15-pinctrl.dtsi [5] to add ETHCK pin in ethernet0_rmii_pins_* node:
For example:

 <STM32_PINMUX('G', 8, AF2)>, /* ETH_RMII_ETHCK */

+ Need also to update TFA devicetree to generate 25Mhz clock (from PLL4P or PLL3Q):
for example if PLL4P in ed1 board: update fdts/stm32mp15xx-edx.dtsi

st,pkcs = <
 CLK_CKPER_HSE
 CLK_FMC_ACLK
 CLK_QSPI_ACLK
 - CLK_ETH_DISABLED
 + CLK_ETH_PLL4P
...
 /* VCO = 600.0 MHz => P = 25, Q = 50, R = 50 */
   pll4: st,pll@3 {
     compatible = "st,stm32mp1-pll";
     reg = <3>;
     cfg = < 1 49 23 11 11 PQR(1,1,1) >;
 };

3.3.3 RMII with 50MHz on ETH_CLK (no PHY Crystal), internal REF_CLK from RCC (Reference clock (standard RMII clock name) is provided by a RCC SoC internal clock)[edit]

For ecosystem release ≤ v3.0.0 , only for STM32MP15x lines More info.png

   ethernet0: ethernet@5800a000 {
       compatible = "st,stm32mp1-dwmac", "snps,dwmac-4.20a";
       reg = <0x5800a000 0x2000>;
       reg-names = "stmmaceth";
       interrupts-extended = <&intc GIC_SPI 61 IRQ_TYPE_LEVEL_HIGH>,
                             <&intc GIC_SPI 62 IRQ_TYPE_LEVEL_HIGH>,
                             <&exti 70 1>;
       interrupt-names = "macirq",
                         "eth_wake_irq",
                         "stm32_pwr_wakeup";
       clock-names = "stmmaceth",
                      "mac-clk-tx",
                      "mac-clk-rx",
                      "eth-ck",
                      "ethstp";
       clocks = <&rcc ETHMAC>,
                      <&rcc ETHTX>,
                      <&rcc ETHRX>,
                      <&rcc ETHCK_K>,
                      <&rcc ETHSTP>;
       st,syscon = <&syscfg 0x4>;
       snps,mixed-burst;
       snps,pbl = <2>;
       snps,en-tx-lpi-clockgating;
       st,eth_ref_clk_sel;               /* In case of U-Boot */ 
      or
       st,eth-ref-clk-sel;               /* In case of Linux Kernel */ 
       snps,axi-config = <&stmmac_axi_config_0>;
       snps,tso;
       power-domains = <&pd_core>;
       status = "disabled";
};

For ecosystem release ≥ v3.1.0

   ethernet0: ethernet@5800a000 {
       compatible = "st,stm32mp1-dwmac", "snps,dwmac-4.20a";
       reg = <0x5800a000 0x2000>;
       reg-names = "stmmaceth";
       interrupts-extended = <&intc GIC_SPI 61 IRQ_TYPE_LEVEL_HIGH>,
                             <&intc GIC_SPI 62 IRQ_TYPE_LEVEL_HIGH>,
                             <&exti 70 1>;
       interrupt-names = "macirq",
                         "eth_wake_irq",
                         "stm32_pwr_wakeup";
       clock-names = "stmmaceth",
                      "mac-clk-tx",
                      "mac-clk-rx",
                      "eth-ck",
                      "ethstp";
       clocks = <&rcc ETHMAC>,
                      <&rcc ETHTX>,
                      <&rcc ETHRX>,
                      <&rcc ETHCK_K>,
                      <&rcc ETHSTP>;
       st,syscon = <&syscfg 0x4>;
       snps,mixed-burst;
       snps,pbl = <2>;
       snps,en-tx-lpi-clockgating;
       st,ext-phyclk;
       snps,axi-config = <&stmmac_axi_config_0>;
       snps,tso;
       power-domains = <&pd_core>;
       status = "disabled";
};
   &ethernet0 {
       status = "okay";
       pinctrl-0 = <&ethernet0_rmii_pins_a>;
       pinctrl-1 = <&ethernet0_rmii_pins_sleep_a>;
       pinctrl-names = "default", "sleep";
       phy-mode = "rmii";
       max-speed = <100>;
       phy-handle = <&phy0>;
       mdio0 {
               #address-cells = <1>;
               #size-cells = <0>;
               compatible = "snps,dwmac-mdio";
               phy0: ethernet-phy@0 {
                       reg = <0>;
               };
       };
   };

+ update stm32mp15-pinctrl.dtsi to add ETHCK pin in ethernet0_rmii_pins_* node:
For example:

 <STM32_PINMUX('G', 8, AF2)>, /* ETH_RMII_ETHCK */

+ Need also to update TFA to generate 50Mhz clock (from PLL4P or PLL3Q):
for example if PLL4P in ed1 board: update fdts/stm32mp15xx-edx.dtsi

st,pkcs = <
 CLK_CKPER_HSE
 CLK_FMC_ACLK
 CLK_QSPI_ACLK
 - CLK_ETH_DISABLED
 + CLK_ETH_PLL4P
...
 /* VCO = 508.0 MHz => P = 50, Q = 60, R = 60 */
   pll4: st,pll@3 {
     compatible = "st,stm32mp1-pll";
     reg = <3>;
    cfg = < 1 49 11 9 9 PQR(1,1,1) >;
  };

3.3.4 RGMII with Crystal on PHY, CLK125 from PHY (Reference clock (standard RGMII clock name) is provided by a Phy Crystal)[edit]

   &ethernet0 {
       status = "okay";
       pinctrl-0 = <&ethernet0_rgmii_pins_a>;
       pinctrl-1 = <&ethernet0_rgmii_pins_sleep_a>;
       pinctrl-names = "default", "sleep";
       phy-mode = "rgmii";
       max-speed = <1000>;
       phy-handle = <&phy0>;
       mdio0 {
               #address-cells = <1>;
               #size-cells = <0>;
               compatible = "snps,dwmac-mdio";
               phy0: ethernet-phy@0 {
                       reg = <0>;
               };
           };
   };

3.3.5 RGMII with 25MHz on ETH_CLK (no PHY Crystal), CLK125 from PHY (Reference clock (standard RGMII clock name) is provided by a RCC SoC internal clock)[edit]

   &ethernet0 {
       status = "okay";
       pinctrl-0 = <&ethernet0_rgmii_pins_a>;
       pinctrl-1 = <&ethernet0_rgmii_pins_sleep_a>;
       pinctrl-names = "default", "sleep";
       phy-mode = "rgmii";
       max-speed = <1000>;
       phy-handle = <&phy0>;
       mdio0 {
               #address-cells = <1>;
               #size-cells = <0>;
               compatible = "snps,dwmac-mdio";
               phy0: ethernet-phy@0 {
                       reg = <0>;
               };
       };
   };

+ update stm32mp15-pinctrl.dtsi to add ETHCK pin in ethernet0_rgmii_pins_* node:
For example:

 <STM32_PINMUX('G', 8, AF2)>, /* ETH_RGMII_ETHCK */

+ Need also to update TFA to generate 25Mhz clock (from PLL4P or PLL3Q):
for example if PLL4P in ed1 board: update fdts/stm32mp15xx-edx.dtsi

st,pkcs = <
 CLK_CKPER_HSE
 CLK_FMC_ACLK
 CLK_QSPI_ACLK
 - CLK_ETH_DISABLED
 + CLK_ETH_PLL4P
...
 /* VCO = 600.0 MHz => P = 25, Q = 50, R = 50 */
   pll4: st,pll@3 {
     compatible = "st,stm32mp1-pll";
     reg = <3>;
     cfg = < 1 49 23 11 11 PQR(1,1,1) >;
 };

3.3.6 RGMII with Crystal on PHY, no 125Mhz from PHY[edit]

For ecosystem release ≤ v3.0.0 only for STM32MP15x lines More info.png

   ethernet0: ethernet@5800a000 {
       compatible = "st,stm32mp1-dwmac", "snps,dwmac-4.20a";
       reg = <0x5800a000 0x2000>;
       reg-names = "stmmaceth";
       interrupts-extended = <&intc GIC_SPI 61 IRQ_TYPE_LEVEL_HIGH>,
                             <&intc GIC_SPI 62 IRQ_TYPE_LEVEL_HIGH>,
                             <&exti 70 1>;
       interrupt-names = "macirq",
                         "eth_wake_irq",
                         "stm32_pwr_wakeup";
       clock-names = "stmmaceth",
                      "mac-clk-tx",
                      "mac-clk-rx",
                      "eth-ck",
                      "ethstp";
       clocks = <&rcc ETHMAC>,
                      <&rcc ETHTX>,
                      <&rcc ETHRX>,
                      <&rcc ETHCK_K>,
                      <&rcc ETHSTP>;
       st,syscon = <&syscfg 0x4>;
       snps,mixed-burst;
       snps,pbl = <2>;
       snps,en-tx-lpi-clockgating;
       st,eth_clk_sel;               /* In case of U-Boot */ 
      or
       st,eth-clk-sel;               /* In case of Linux Kernel */ 
       snps,axi-config = <&stmmac_axi_config_0>;
       snps,tso;
       power-domains = <&pd_core>;
       status = "disabled";
};

For ecosystem release ≥ v3.1.0

   ethernet0: ethernet@5800a000 {
       compatible = "st,stm32mp1-dwmac", "snps,dwmac-4.20a";
       reg = <0x5800a000 0x2000>;
       reg-names = "stmmaceth";
       interrupts-extended = <&intc GIC_SPI 61 IRQ_TYPE_LEVEL_HIGH>,
                             <&intc GIC_SPI 62 IRQ_TYPE_LEVEL_HIGH>,
                             <&exti 70 1>;
       interrupt-names = "macirq",
                         "eth_wake_irq",
                         "stm32_pwr_wakeup";
       clock-names = "stmmaceth",
                      "mac-clk-tx",
                      "mac-clk-rx",
                      "eth-ck",
                      "ethstp";
       clocks = <&rcc ETHMAC>,
                      <&rcc ETHTX>,
                      <&rcc ETHRX>,
                      <&rcc ETHCK_K>,
                      <&rcc ETHSTP>;
       st,syscon = <&syscfg 0x4>;
       snps,mixed-burst;
       snps,pbl = <2>;
       snps,en-tx-lpi-clockgating;
       st,ext-phyclk;
       snps,axi-config = <&stmmac_axi_config_0>;
       snps,tso;
       power-domains = <&pd_core>;
       status = "disabled";
};
   &ethernet0 {
       status = "okay";
       pinctrl-0 = <&ethernet0_rgmii_pins_a>;
       pinctrl-1 = <&ethernet0_rgmii_pins_sleep_a>;
       pinctrl-names = "default", "sleep";
       phy-mode = "rgmii";
       max-speed = <1000>;
       phy-handle = <&phy0>;
       mdio0 {
               #address-cells = <1>;
               #size-cells = <0>;
               compatible = "snps,dwmac-mdio";
               phy0: ethernet-phy@0 {
                       reg = <0>;
               };
       };
   };

+ update stm32mp15-pinctrl.dtsi to delete CLK125 pin (also no need of ETHCK pin) in ethernet0_rgmii_pins_* node:

+ Need also to update TFA to generate 125Mhz clock (from PLL4P or PLL3Q):
for example if PLL4P in ed1 board: update fdts/stm32mp15xx-edx.dtsi

st,pkcs = <
 CLK_CKPER_HSE
 CLK_FMC_ACLK
 CLK_QSPI_ACLK
 - CLK_ETH_DISABLED
 + CLK_ETH_PLL4P
...
 /* VCO = 750.0 MHz => P = 125, Q = 62.5, R = 62.5 */
 pll4: st,pll@3 {
     compatible = "st,stm32mp1-pll";
     reg = <3>;
     cfg = < 3 124 5 11 11 PQR(1,1,1) >;
 };

4 How to configure a PHY reset signal[edit]

Some Ethernet PHY have possibility to drive PHY reset using GPIO

   &ethernet0 {
       status = "okay";
       pinctrl-0 = <&ethernet0_rgmii_pins_a>;
       pinctrl-1 = <&ethernet0_rgmii_pins_sleep_a>;
       pinctrl-names = "default", "sleep";
       phy-mode = "rgmii";
       max-speed = <1000>;
       phy-handle = <&phy0>;
       mdio0 {
               #address-cells = <1>;
               #size-cells = <0>;
               compatible = "snps,dwmac-mdio";
               phy0: ethernet-phy@0 {
                       compatible = "ethernet-phy-id0007.c131";
                       reset-gpios = <&gpioa 4 GPIO_ACTIVE_LOW | GPIO_PULL_UP>  
                         reset-assert-us = <1000>;
                         reset-deassert-us = <2000>;
                         reg = <0>;
               };
       };
   };

For kernel update see "reset-gpios" in Documentation/devicetree/bindings/net/ethernet-phy.yaml[6]


You need to find and replace value 0007.c131 corresponding to your Ethernet PHY: this can be found in datasheet of the Ethernet PHY, and find PHY Identifier 1 and PHY Identifier 2 registers.

For U-Boot same syntax of kernel, except that "reset-assert-us" and "reset-deassert-us" properties which are not managed (values of this properties are hardcoded in driver (udelay(2)), so you can change these value in function eqos_start_resets_stm32 of file dwc_eth_qos.c[7]


5 How to enable and use Wake on LAN (WoL) from PHY[edit]

Under construction.png The feature explained in this section is under construction and will be available only with v4.1.0 ecosystem delivery

Ethernet 1 of STM32MP135x-DK Discovery kit Warning.png has the possibility to use Magic Packet to wake up board from Standby mode.

        eth1: eth1@5800a000 {
            compatible = "snps,dwmac-4.20a", "st,stm32mp13-dwmac";
            reg = <0x5800a000 0x2000>;
            reg-names = "stmmaceth";
            ....
            snps,mixed-burst;
            snps,pbl = <2>;
            snps,axi-config = <&stmmac_axi_config_0>;
            snps,tso;
            '''power-domains = <&pd_core>;''' => to remove to activate WoL from PHY
            '''wakeup-source;'''              => to remove to activate WoL from PHY
            status = "disabled";
         };


    &eth1 {
        status = "okay";
        pinctrl-0 = <&eth1_rmii_pins_a>;
        pinctrl-1 = <&eth1_rmii_sleep_pins_a>;
        pinctrl-names = "default", "sleep";
        phy-mode = "rmii";
        max-speed = <100>;
        phy-handle = <&phy0_eth1>;
        mdio1 {
                #address-cells = <1>;
                #size-cells = <0>;
                compatible = "snps,dwmac-mdio";
                phy0_eth1: ethernet-phy@0 {
                          compatible = "ethernet-phy-id0007.c131";
                          reset-gpios =  <&mcp23017 9 GPIO_ACTIVE_LOW>;
                          reg = <0>;
                          '''wakeup-source;'''      => to add to activate WoL from PHY
                };
        };
    };

To enable wakeup source

 echo enabled > /sys/devices/platform/soc/5800a000.eth1/mdio_bus/stmmac-0/stmmac-0\:00/power/wakeup

To wake up board from host:

  etherwake -i enp0s25 @MAC_Of_TheBoard

6 How to configure Ethernet using CubeMX[edit]

The STM32CubeMX tool can be used to configure the STM32MPU device and get the corresponding platform configuration device tree files.
The STM32CubeMX may not support all the properties described in the above DT bindings documentation paragraph. If so, the tool inserts user sections in the generated device tree. These sections can then be edited to add some properties and they are preserved from one generation to another. Refer to STM32CubeMX user manual for further information.

7 References[edit]