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Wake-On-Lan on iMX28 and FEC LAN8720-A

Question asked by Gianluca Renzi on Jun 21, 2018
Latest reply on Jun 24, 2018 by igorpadykov

Hi everybody!


I have a new design issue for a customer who wants to use iMX280 and a sort of power-saving feature.

The board is equipped with 4Gb eMMC and a fairly-stock Debian Stretch 9.4 and a vanilla Linux Kernel 4.9 and everything is working good so far.

# lsb_release -a
No LSB modules are available.
Distributor ID: Debian
Description:    Debian GNU/Linux 9.4 (stretch)
Release:        9.4
Codename:       stretch

# uname -a
Linux edelin-ek420-08d411 4.9.78 #1 PREEMPT Wed Jun 20 17:16:59 CEST 2018 armv5tejl GNU/Linux

The board has an RTC (PCF8563) battery powered and a sort of circuitry to wakeup at some hours and it is working good: it uses sysfs to wakeup every hour using this simple script:

echo 0 > /sys/class/rtc/rtc0/wakealarm
echo `date '+%s' -d '+ 60 minutes'` > /sys/class/rtc/rtc0/wakealarm

Naturally it has a "gpio-poweroff" pin to shutdown itself when it reaches the poweroff syscall. And this stuff is working good...

    gpio-poweroff {
        compatible = "gpio-poweroff";
        gpios = <&gpio2 9 GPIO_ACTIVE_HIGH>;
        status = "okay";

The board has a special button and it is used as wakeup source as defined in the device-tree:

    gpio-buttons {
        compatible = "gpio-keys";
        pinctrl-names = "default";
        pinctrl-0 = <&board_buttons>;
        status = "okay";

        wakeupbutton {
            label = "WAKEUP_BTN";
            gpios = <&gpio1 26 GPIO_ACTIVE_LOW>;
            linux,code = <KEY_WAKEUP>;

and when I put the board in sleep mode (1):

echo freeze > /sys/power/state

or (2)

echo mem > /sys/power/state

it works fine!

Now the customer wants to wakeup the board when in sleep (1) or (2), via ethernet using wakeonlan feature.

        mac0: ethernet@800f0000 {
            phy-mode = "rmii";
            pinctrl-names = "default";
            pinctrl-0 = <&mac0_pins_a>;
            phy-supply = <&reg_3p3v>;
            phy-reset-gpios = <&gpio3 17 0>;
            phy-reset-duration = <100>;
            status = "okay";

There is fsl,magic-packet for mac0, so in this way I can  have wakeup entries in /sys/class/net/eth0/power/wakeup*:

echo enabled > /sys/class/net/eth0/power/wakeup

and ethtool eth0 gives me:

# ethtool eth0
Settings for eth0:
        Supported ports: [ TP MII ]
        Supported link modes:   10baseT/Half 10baseT/Full
                                100baseT/Half 100baseT/Full
        Supported pause frame use: No
        Supports auto-negotiation: Yes
        Advertised link modes:  10baseT/Half 10baseT/Full
                                100baseT/Half 100baseT/Full
        Advertised pause frame use: No
        Advertised auto-negotiation: Yes
        Link partner advertised link modes:  10baseT/Half 10baseT/Full
                                             100baseT/Half 100baseT/Full
        Link partner advertised pause frame use: Symmetric
        Link partner advertised auto-negotiation: Yes
        Speed: 100Mb/s
        Duplex: Full
        Port: MII
        PHYAD: 0
        Transceiver: internal
        Auto-negotiation: on
        Supports Wake-on: g
        Wake-on: g
        Link detected: yes

# ifconfig
eth0: flags=4163<UP,BROADCAST,RUNNING,MULTICAST> mtu 1500
inet netmask broadcast
inet6 fe80::21b:c5ff:fe08:d411 prefixlen 64 scopeid 0x20<link>
ether 00:1b:c5:08:d4:11 txqueuelen 1000 (Ethernet)
RX packets 296 bytes 32987 (32.2 KiB)
RX errors 0 dropped 0 overruns 0 frame 0
TX packets 73 bytes 10340 (10.0 KiB)
TX errors 0 dropped 0 overruns 0 carrier 0 collisions 0

lo: flags=73<UP,LOOPBACK,RUNNING> mtu 65536
inet netmask
inet6 ::1 prefixlen 128 scopeid 0x10<host>
loop txqueuelen 1 (Local Loopback)
RX packets 2 bytes 78 (78.0 B)
RX errors 0 dropped 0 overruns 0 frame 0
TX packets 2 bytes 78 (78.0 B)
TX errors 0 dropped 0 overruns 0 carrier 0 collisions 0

So I supposed the wake-on-lan features was working good. But it does not indeed! I was wrong.

From another PC on the same subnet I sent the wol packet:

$ wakeonlan -i 00:1b:c5:08:d4:11
Sending magic packet to with 00:1b:c5:08:d4:11

When I put the device in sleep mode as before (1) or (2) it NEVER wakes up.

The Ethernet Link seems to be lost when in sleep mode looking at the lights in the ethernet switch where the board is connected. I thought the link MUST BE ACTIVE during the sleep mode if someone wants to wake the board via wake-on-lan. Is it right assumption? Or not?

Please point me somewhere... I need a sparkle...

Gianluca Renzi