Ethernet PHY does not work with 100 Mbps Full Duplex but works with 10 Mbps Full Duplex

[DmnSd]

Hello,

we want to bring up our own board with STM32MP and ethernet phy LAN8720 (10/100 Mbps).

Seems that kernel is recognizing ethernet phy on boot up and configure it with 100 Mbps Full Duplex.

[    2.907461] stm32-dwmac 5800a000.ethernet: IRQ eth_lpi not found
[    2.912172] stm32-dwmac 5800a000.ethernet: PTP uses main clock
[    2.917902] stm32-dwmac 5800a000.ethernet: no reset control found
[    2.923940] stm32-dwmac 5800a000.ethernet: No phy clock provided...
[    2.930837] stm32-dwmac 5800a000.ethernet: User ID: 0x40, Synopsys ID: 0x42
[    2.937162] stm32-dwmac 5800a000.ethernet:   DWMAC4/5
[    2.942051] stm32-dwmac 5800a000.ethernet: DMA HW capability register supported
[    2.949371] stm32-dwmac 5800a000.ethernet: RX Checksum Offload Engine supported
[    2.956661] stm32-dwmac 5800a000.ethernet: TX Checksum insertion supported
[    2.963500] stm32-dwmac 5800a000.ethernet: Wake-Up On Lan supported
[    2.969774] stm32-dwmac 5800a000.ethernet: TSO supported
[    2.975050] stm32-dwmac 5800a000.ethernet: Enable RX Mitigation via HW Watchdog Timer
[    2.982910] stm32-dwmac 5800a000.ethernet: TSO feature enabled
[   14.414385] using random self ethernet address
[   14.478328] using random host ethernet address
[   17.106903] stm32-dwmac 5800a000.ethernet eth0: PHY [stmmac-0:01] driver [SMSC LAN8710/LAN8720]
[   17.157900] stm32-dwmac 5800a000.ethernet eth0: No Safety Features support found
[   17.163849] stm32-dwmac 5800a000.ethernet eth0: IEEE 1588-2008 Advanced Timestamp supported
[   17.217406] stm32-dwmac 5800a000.ethernet eth0: registered PTP clock
[   17.248317] stm32-dwmac 5800a000.ethernet eth0: configuring for phy/rmii link mode
[   19.369837] stm32-dwmac 5800a000.ethernet eth0: Link is Up - 100Mbps/Full - flow control rx/tx
[   19.462378] IPv6: ADDRCONF(NETDEV_CHANGE): eth0: link becomes ready

However there is no connection to my router. I do not get an ip address.

~# ifconfig
eth0      Link encap:Ethernet  HWaddr 86:6F:B4:A4:73:6B
          UP BROADCAST RUNNING MULTICAST  MTU:1500  Metric:1
          RX packets:570 errors:0 dropped:0 overruns:0 frame:0
          TX packets:434 errors:0 dropped:0 overruns:0 carrier:0
          collisions:0 txqueuelen:1000
          RX bytes:92105 (89.9 KiB)  TX bytes:77256 (75.4 KiB)
          Interrupt:50

If I change my ethernet configuration with `ethtool` to 10 Mbps Full Duplex I get an ip address and a connection.

~# ethtool -s eth0 speed 10 duplex full
[ 1980.176613] stm32-dwmac 5800a000.ethernet eth0: Link is Down
[ 1982.888396] stm32-dwmac 5800a000.ethernet eth0: Link is Up - 10Mbps/Full - flow control rx/tx
 
~# ifconfig
eth0      Link encap:Ethernet  HWaddr 86:6F:B4:A4:73:6B
          inet addr:192.168.10.155  Bcast:192.168.10.255  Mask:255.255.255.0
          inet6 addr: fe80::9ed8:22fe:9399:c183/64 Scope:Link
          UP BROADCAST RUNNING MULTICAST  MTU:1500  Metric:1
          RX packets:729 errors:0 dropped:0 overruns:0 frame:0
          TX packets:552 errors:0 dropped:0 overruns:0 carrier:0
          collisions:0 txqueuelen:1000
          RX bytes:117708 (114.9 KiB)  TX bytes:93743 (91.5 KiB)
          Interrupt:50
 
~# iperf3 -c 192.168.10.203
Connecting to host 192.168.10.203, port 5201
[  5] local 192.168.10.155 port 47588 connected to 192.168.10.203 port 5201
[ ID] Interval           Transfer     Bitrate         Retr  Cwnd
[  5]   0.00-1.00   sec  1.20 MBytes  10.0 Mbits/sec    0   29.7 KBytes
[  5]   1.00-2.00   sec  1.14 MBytes  9.59 Mbits/sec    0   29.7 KBytes
[  5]   2.00-3.00   sec  1.09 MBytes  9.17 Mbits/sec    0   29.7 KBytes
[  5]   3.00-4.00   sec  1.14 MBytes  9.59 Mbits/sec    0   29.7 KBytes
[  5]   4.00-5.00   sec  1.09 MBytes  9.17 Mbits/sec    0   29.7 KBytes
[  5]   5.00-6.00   sec  1.14 MBytes  9.59 Mbits/sec    0   29.7 KBytes
[  5]   6.00-7.00   sec  1.14 MBytes  9.59 Mbits/sec    0   29.7 KBytes
[  5]   7.00-8.00   sec  1.09 MBytes  9.17 Mbits/sec    0   29.7 KBytes
[  5]   8.00-9.00   sec  1.14 MBytes  9.59 Mbits/sec    0   29.7 KBytes
[  5]   9.00-10.00  sec  1.09 MBytes  9.17 Mbits/sec    0   29.7 KBytes
- - - - - - - - - - - - - - - - - - - - - - - - -
[ ID] Interval           Transfer     Bitrate         Retr
[  5]   0.00-10.00  sec  11.3 MBytes  9.47 Mbits/sec    0             sender
[  5]   0.00-10.01  sec  11.2 MBytes  9.41 Mbits/sec                  receiver
 
iperf Done.

This is my device tree configuration:

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>,
      <&exti 70 IRQ_TYPE_LEVEL_HIGH>;
interrupt-names = "macirq",
  "eth_wake_irq";
clock-names = "stmmaceth",
      "mac-clk-tx",
      "mac-clk-rx",
      "ethstp";
clocks = <&rcc ETHMAC>,
<&rcc ETHTX>,
<&rcc ETHRX>,
<&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";
};
 
&ethernet0{
	pinctrl-names = "default", "sleep";
	pinctrl-0 = <&eth1_pins_mx>;
	pinctrl-1 = <&eth1_sleep_pins_mx>;
	status = "okay";
 
	phy-mode = "rmii";
	max-speed = <100>;
	phy-handle = <&phy0>;
 
	mdio0 {
		#address-cells = <1>;
		#size-cells = <0>;
		compatible = "snps,dwmac-mdio";
		reset-gpios = <&gpioz 7 GPIO_ACTIVE_LOW>;
		reset-delay-us = <100000>;
 
		phy0: ethernet-phy@1 {
			reg = <1>;
			smsc,disable-energy-detect;
		};
	};
};
 
eth1_pins_mx: eth1_mx-0 {
		pins1 {
			pinmux = <STM32_PINMUX('A', 1, AF11)>, /* ETH1_REF_CLK */
					 <STM32_PINMUX('C', 1, AF11)>, /* ETH1_MDC */
					 <STM32_PINMUX('G', 13, AF11)>, /* ETH1_TXD0 */
					 <STM32_PINMUX('G', 14, AF11)>; /* ETH1_TXD1 */
			bias-disable;
			drive-push-pull;
			slew-rate = <1>;
		};
		pins2 {
			pinmux = <STM32_PINMUX('A', 2, AF11)>; /* ETH1_MDIO */
			bias-disable;
			drive-push-pull;
			slew-rate = <0>;
		};
		pins3 {
			pinmux = <STM32_PINMUX('A', 7, AF11)>, /* ETH1_CRS_DV */
					 <STM32_PINMUX('C', 4, AF11)>, /* ETH1_RXD0 */
					 <STM32_PINMUX('C', 5, AF11)>; /* ETH1_RXD1 */
			bias-disable;
		};
		pins4 {
			pinmux = <STM32_PINMUX('B', 11, AF11)>; /* ETH1_TX_EN */
		};
	};

I have also read this article but do not get a solution.

Is there a way to configure STM32MP MAC exactly for 100 Mbps?

Or are there any other configurations I can access?

It's strange that there is no problem with 10 Mbps, but 100 Mbps are not possible....

Thanks for help!

Kind regards

[PatrickF · Accepted solution]

Hi,

I assume you checked your HW and RJ45 wiring and cable.

Please check Device Tree eth1_pins_mx pin4, seems "bias-disable; drive-push-pull; slew-rate = <1>;" are missing as TX_EN is an output of the STM32MP1.

Your issue is unlikely linked to reset signal, but please have a look to https://wiki.st.com/stm32mpu/wiki/Ethernet_device_tree_configuration#How_to_configure_a_PHY_reset_signal

Regards.

[DmnSd]

Thanks @PatrickF​ 

bias-disable;
drive-push-pull;
slew-rate = <1>;

was missing in device tree TX_EN.

Now I have my 100 Mbps.

Thanks for good and fast answer!