ls1021a custom board: issue with "Link Up" for the board with two ethernet ports

[evgeniyMatskevich]

Hi,
We have a custom board with ls1021a processor. And we see strange behaviour with ethernet interfaces in u-boot.

We have two ethernet ports on our board: eth0 and eth1.

We can see manageable Ethernet PHYs:
=> mdio list
mdio@2d24000:
0 - RealTek RTL8211F <--> ethernet@2d50000
2 - RealTek RTL8211F <--> ethernet@2d10000
mdio@2d64000:

ethernet@2d10000 corresponds to "eth0" port and ethernet@2d50000 corresponds to "eth1" port.

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When we insert cable only in the "eth1" port we can check link status for external PHY:
eth1
=> mdio read ethernet@2d50000 1
Reading from bus mdio@2d24000
PHY at address 0:
1 - 0x79ad

According to this documentation https://docs.nxp.com/bundle/GUID-1B480175-7E30-4237-A58E-3F0AD1C61250/page/GUID-EE98B00F-B379-4FE3-9... the 'Link Status' bit is bit #2 (from the left) of the last nibble. The nibble of interest is "d" (d = b'1101').
And therefore the 'Link Status' = 1, which means 'link up'.

eth0
=> mdio read ethernet@2d10000 1
Reading from bus mdio@2d24000
PHY at address 2:
1 - 0x7989

The nibble of interest is "9" (d = b'1001').
And therefore the 'Link Status' = 0, which means 'link down'.

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But when we insert cable only in the "eth0":

eth1
=> mdio read ethernet@2d50000 1
Reading from bus mdio@2d24000
PHY at address 0:
1 - 0x79ad

'Link Status' = 1, which means 'link up'.

eth0
=> mdio read ethernet@2d10000 1
Reading from bus mdio@2d24000
PHY at address 2:
1 - 0x79ad

Link Status' = 1, which means 'link up'.

We  see 'Link Status' = 1 for "eth1" and "eth0", but only "eth0" connected with cable.

In this case when we connect the second cable to the "eth1" port it is not available for using.

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Therefore we can't normally work with "eth1" port when "eth0" is used too. 

Here is the RCW that we use:

00000000: 0608000c 00000000 00000000 00000000
00000010: 20000000 08447900 e0105a00 21046000
00000020: 00000000 00000000 00000000 0003f300
00000030: 20000000 2484b340 00000000 00000000

Could you advice a solution to resolve the issue?

[JosephAtNXP]

Hi,

Thank you for your interest in NXP Semiconductor products,

Could you share your device tree to check on it? Thank you in advance.

Regards

[evgeniyMatskevich]

Thanks for the answer.
Here is the dts file.

[JosephAtNXP]

Hi,

At first approach I saw that you were using the same PHY as the document, which differs from LS1021A TWR design.

But with the device tree I see that you are declaring an SGMII connection which isn't the RTL8211 IF, where is the error here?

What PHY are you using?

What IF are you using? I am in the meantime looking at RCW.

Thank you

[evgeniyMatskevich]

Hi, we use RTL8211FS PHY. It supports SGMII - https://www.realtek.com/en/products/connected-media-ics/item/rtl8211fs-i-vs-cg