topic Re: imx6q porting from kernel 5.4 to 6.1 breaks eth0, it is detected but with NO-CARRIER in i.MX Processors

imx6q porting from kernel 5.4 to 6.1 breaks eth0, it is detected but with NO-CARRIER

Lars71dk — Wed, 24 Jul 2024 06:35:31 GMT

Hello,

Moving from dunfell 5.4 to scarthgap kernel 6.1 I face an issue with eth0.

It is detected:

[ 1.223578] fec 2188000.ethernet eth0: registered PHC device 0
[ 1.826261] Generic PHY 2188000.ethernet-1:01: attached PHY driver (mii_bus:phy_addr=2188000.ethernet-1:01, irq=POLL)

But link is down, and I can't up it:
2: eth0: <NO-CARRIER,BROADCAST,MULTICAST,UP> mtu 1500 qdisc pfifo_fast qlen 1000
link/ether 00:50:55:01:37:8f brd ff:ff:ff:ff:ff:ff

I notice these two lines missing dmesg, compared with the working 5.4:
[ 0.179949] libphy: Fixed MDIO Bus: probed
[ 0.188184] libphy: fec_enet_mii_bus: probed

I tried this patch, to no avail:
&fec {
pinctrl-names = "default";
pinctrl-0 = <&pinctrl_enet>;
phy-mode = "rmii";
+ phy-handle = <&ethphy>;
phy-reset-gpios = <&gpio3 12 GPIO_ACTIVE_LOW>;
status = "okay";
+
+ mdio {
+ #address-cells = <1>;
+ #size-cells = <0>;
+
+ ethphy: ethernet-phy@1 {
+ reg = <1>;
+ qca,clk-out-frequency = <125000000>;
+ };
+ };
};

What am I possibly missing?

A LAN9512 based port, eth1, works.

Thanks,

Lars

Re: imx6q porting from kernel 5.4 to 6.1 breaks eth0, it is detected but with NO-CARRIER

Lars71dk — Wed, 24 Jul 2024 08:07:59 GMT

In addition, my kernel config includes:
CONFIG_MDIO_DEVICE=y
CONFIG_MDIO_BUS=y
CONFIG_FWNODE_MDIO=y
CONFIG_OF_MDIO=y
CONFIG_MDIO_DEVRES=y
CONFIG_PHYLIB=y
CONFIG_MICREL_PHY=y

Re: imx6q porting from kernel 5.4 to 6.1 breaks eth0, it is detected but with NO-CARRIER

Zhiming_Liu — Fri, 26 Jul 2024 08:50:58 GMT

Hi @Lars71dk

Can you share your device tree node about eth0?

Best Regards
Zhiming

Re: imx6q porting from kernel 5.4 to 6.1 breaks eth0, it is detected but with NO-CARRIER

Lars71dk — Fri, 26 Jul 2024 12:49:31 GMT

Hi Zhiming,

fec: ethernet@2188000 {
compatible = "fsl,imx6q-fec";
reg = <0x02188000 0x4000>;
interrupt-names = "int0", "pps";
interrupts = <0 118 4>,
<0 119 4>;
clocks = <&clks 117>,
<&clks 117>,
<&clks 190>,
<&clks 190>;
clock-names = "ipg", "ahb", "ptp", "enet_out";
assigned-clocks = <&clks 190>;
assigned-clock-rates = <125000000>;
fsl,stop-mode = <&gpr 0x34 27>;
fsl,wakeup_irq = <0>;
status = "disabled";
};

Regards, Lars

Re: imx6q porting from kernel 5.4 to 6.1 breaks eth0, it is detected but with NO-CARRIER

Lars71dk — Wed, 31 Jul 2024 10:56:03 GMT

Hi Zhiming,
Where you able to check or can I provide additional information for troubleshooting?
Thanks,
Lars

Re: imx6q porting from kernel 5.4 to 6.1 breaks eth0, it is detected but with NO-CARRIER

Zhiming_Liu — Thu, 01 Aug 2024 02:25:39 GMT

Hi @Lars71dk

No obvious problems, but you need to check that the LIBPHY driver has been compiled in after the kernel has finished compiling, try adding some printing to verify that.

Best Regards
Zhiming

Re: imx6q porting from kernel 5.4 to 6.1 breaks eth0, it is detected but with NO-CARRIER

Lars71dk — Mon, 23 Sep 2024 08:51:49 GMT

Hi Liu,

I added trace lines in the driver, and also ran the ethtool, still the fec is there but there is no Link.
Details, dmesg log lines - the inits returns ok. Yet the two 'probed' phylib lines does not appear.

[ 0.257023] fixed_mdio_bus_init...
[ 0.257153] fixed_mdio_bus_init mdiobus_register...
[ 0.257662] fixed_mdio_bus_init return 0
[ 0.259284] fec_probe...
[ 0.262650] fec_probe fec_enet_init...
[ 0.263915] fec_enet_mii_init of_mdiobus_register...
[ 0.267206] fec_enet_mii_init return 0
[ 0.267748] fec 2188000.ethernet eth0: registered PHC device 0
[ 0.267767] fec_probe return 0

[ 0.460465] Generic PHY 2188000.ethernet-1:01: attached PHY driver (mii_bus:phy_addr=2188000.ethernet-1:01, irq=POLL)
[ 1.483372] SMSC LAN8700 usb-001:003:01: attached PHY driver (mii_bus:phy_addr=usb-001:003:01, irq=294)

This line comes with kernel 5.4, but is now missing:
[ 3.677672] fec 2188000.ethernet eth0: Link is Up - 100Mbps/Full - flow control rx/tx

Restarting eth0 does not help:
ip link set eth0 down && ip link set eth0 up

Still ethtool indicates com. with the phy, but indicates no link:
root@cpb539:/opt/fccapps# ./ethtool eth0
Settings for eth0:
Supported ports: [ TP MII ]
Supported link modes: 10baseT/Half 10baseT/Full
100baseT/Half 100baseT/Full
Supported pause frame use: Symmetric
Supports auto-negotiation: Yes
Supported FEC modes: Not reported
Advertised link modes: 10baseT/Half 10baseT/Full
100baseT/Half 100baseT/Full
Advertised pause frame use: Symmetric
Advertised auto-negotiation: Yes
Advertised FEC modes: Not reported
Speed: Unknown!
Duplex: Unknown! (255)
Auto-negotiation: on
Port: MII
PHYAD: 1
Transceiver: external
Supports Wake-on: d
Wake-on: d
Link detected: no

What could be the next step in troubleshooting?

Thanks, Lars

Re: imx6q porting from kernel 5.4 to 6.1 breaks eth0, it is detected but with NO-CARRIER

Lars71dk — Mon, 23 Sep 2024 09:18:54 GMT

The phy is the KSZ9031.

Re: imx6q porting from kernel 5.4 to 6.1 breaks eth0, it is detected but with NO-CARRIER

Lars71dk — Mon, 23 Sep 2024 11:51:38 GMT

I found the driver for micrel ksz9031 had a change between 5.4 and 6.1:

Remove fixup and change phy-mode to rgmii-id:
[v1,1/7] ARM i.MX6q: remove PHY fixup for KSZ9031
https://patches.linaro.org/project/netdev/patch/20210203091857.16936-2-o.rempel@pengutronix.de/

I changed the phy-mode to rgmii-id (as well as the others) but still no link. Also, the link LED driven by the phy is off. Still, something missing in order to enable the phy?

Thanks

Re: imx6q porting from kernel 5.4 to 6.1 breaks eth0, it is detected but with NO-CARRIER

Lars71dk — Wed, 25 Sep 2024 08:34:07 GMT

Sorry, the phy device is the DP83848K.

Re: imx6q porting from kernel 5.4 to 6.1 breaks eth0, it is detected but with NO-CARRIER

Lars71dk — Wed, 25 Sep 2024 15:25:22 GMT

Update:

On another 6.1 platform I also don't get the 'phylib' proped messages, so I guess they disappeared since 5.4 and does not relate to the link issue.

I added the kernel module for the Micrel Phy and correctly get:
[ 1.900471] NS DP83848C 10/100 Mbps PHY 2188000.ethernet-1:01: attached PHY driver (mii_bus:phy_addr=2188000.ethernet-1:01, irq=POLL)

Yet - there is no link coming up. If I boot a 5.4 linux, it works - so my cables and hw must be ok.

I also still apply this patch, as was used in 5.4 and relates to the clock setup:

+++ b/drivers/clk/imx/clk-imx6q.c
@@ -1019,6 +1019,9 @@ static void __init imx6q_clocks_init(struct device_node *ccm_node)
clk_prepare_enable(hws[IMX6QDL_CLK_USBPHY2_GATE]->clk);
}

+ /*Set enet_ref clock to 50M to supply for RGMII tx_clk */
+ clk_set_rate(hws[IMX6QDL_CLK_ENET_REF]->clk, 50000000);

Thanks,

Lars

Re: imx6q porting from kernel 5.4 to 6.1 breaks eth0, it is detected but with NO-CARRIER

Lars71dk — Mon, 30 Sep 2024 10:26:05 GMT

Hi Liu,

So the issue seems to be the enet_ref clock which is at the default 125MHz. I try to set it to 50MHz in imx6q_clocks_init:
clk_set_rate(hws[IMX6QDL_CLK_ENET_REF]->clk, 50000000);

It worked on 5.4 but not 6.1

Lars

Re: imx6q porting from kernel 5.4 to 6.1 breaks eth0, it is detected but with NO-CARRIER

Lars71dk — Mon, 30 Sep 2024 12:26:00 GMT

Hi Liu,

In the device tree I change the assigned IMX6QDL_CLK_ENET_REF clock from 125 to 50MHz:

assigned-clock-rates = <50000000>;

Now the clock is correct. But why doesn't clk_set_rate() work?

Please comment, thanks.

Lars