Re: BCM54220: After the BCM54220 closes the auto-negotiation, the configuration forces the 1000M network port to be linked down all the time.

wangxiaolei
2023-02-21T08:04:57Z

On 2/18/23 1:13 AM, Florian Fainelli wrote:
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> On 2/17/23 00:06, Wang, Xiaolei wrote:
>> hi
>>
>>      When I use the nxp-imx7 board, eth0 is connected to the PC, eth0 is
>> turned off the auto-negotiation mode, and the configuration is forced to
>> 10M, 100M, 1000M. When configured to force 1000M，
>>      The link status of phy status reg(0x1) is always 0, and the chip of
>> phy is BCM54220, but I did not find the relevant datasheet on BCM
>> official website, does anyone have any suggestions or the datasheet of
>> BCM54220?
>
> I don't have access to a system with a BCM54220 but can look at the
> datasheet, could you provide the full output of mii-diag in both cases?
In auto-negotiation mode: normal Link Up, dump of registers:

Read: reg0, 0x1140
Read: reg1, 0x796d
Read: reg2, 0x600d
Read: reg3, 0x8589
Read: reg4, 0x05e1
Read: reg5, 0xc5e1
Read: reg6, 0x006d
Read: reg7, 0x2001
Read: reg8, 0x5bbc
Read: reg9, 0x0200
Read: rega, 0x3800
Read: regb, 0x0000
Read: regc, 0x0000
Read: regd, 0x0000
Read: rege, 0x0000
Read: regf, 0x3000
Read: reg10, 0x0000
Read: reg11, 0x0301
Read: reg12, 0x0000
Read: reg13, 0x0000
Read: reg14, 0x0000
Read: reg15, 0xff1f
Read: reg16, 0x043e
Read: reg17, 0xffff
Read: reg18, 0x8800
Read: reg19, 0x3490
Read: reg1a, 0x0000
Read: reg1b, 0x0000

When auto-negotiation is disabled and configured as forced 1000M mode,
the register dump:

Read: reg0, 0x0140
Read: reg1, 0x7949
Read: reg2, 0x600d
Read: reg3, 0x8589
Read: reg4, 0x0401
Read: reg5, 0x0000
Read: reg6, 0x0064
Read: reg7, 0x2001
Read: reg8, 0x0000
Read: reg9, 0x0200
Read: rega, 0x0000
Read: regb, 0x0000
Read: regc, 0x0000
Read: regd, 0x0000
Read: rege, 0x0000
Read: regf, 0x3000
Read: reg10, 0x0000
Read: reg11, 0x0000
Read: reg12, 0x0000
Read: reg13, 0x0000
Read: reg14, 0x0000
Read: reg15, 0x0700
Read: reg16, 0x0006
Read: reg17, 0xffff
Read: reg18, 0x8000
Read: reg19, 0x051d
Read: reg1a, 0x0000
Read: reg1b, 0x0000
> What do the PC report as far as link partner advertisement goes etc.?
The other end of the port is also in the link down state.
>
> You are using a twister pair cable to connect your two systems?

I am using copper mode.

And I found that the AR8031 PHY also has this problem. In the case of
auto-negotiation, 1000M can be negotiated. When auto-negotiation is
turned off, 10M and 100M can be Link Up, but 1000M can also be Link
Down. I read the AR8031 manual https://pdf1.
alldatasheet.com/datasheet-pdf/view/1132454/ETC2/AR8035.html, there is
only such a statement "If auto-negotiation is disabled, a 10 BASE-Te or
100 BASE-TX can be manually selected using the IEEE MII registers .”

thanks

xiaolei

> --
> Florian
>