Linux/DP83867IR: cannot complete MII loopback test

kent lu

Part Number: DP83867IR

Tool/software: Linux

Dear Experts,

We are using DP83867I+ZYNQ7010 FPGA on our customer board, the interface between FPGA and PHY is RGMII. Now we find that PHY register can be accessed via MDIO normally, while the network connection is unreachable.

1. When Pluging and un-pluging RJ45, there are indications in ZYNQ OS: Link up and Link down accordingly.

2. Ping from PC to customer board, and check by ifconfig command in Linux, find RX packages are increasing all the time, while TX not change.

We plan to use MII Loopback to test the physical signal loop. According to the process in datasheet:

a) Disable Auto-Negotiation.

b) Disable Auto-MDIX

c) Set LOOPCR to 0xE720

d) CTRL BIT14 soft restart

We find PHY cannot be accessed anymore via MDIO once LOOPCR is set to 0xE720, until reset.

Would you kindly help me to check the steps above for any mistakes, or clarify the correct producers of MII loopback test, thanks a lot.

over 7 years ago

0 Ross Pimentel over 7 years ago

TI__Mastermind 23675 points

Hi Kent,

When you are writing to register 0xFE are you using extended register access?
When you say that the PHY is not accessible, does this mean that you get no response when you read any register?
If the returned value 0xFFFF or 0x0?

0 kent lu over 7 years ago in reply to Ross Pimentel

Prodigy 230 points

Hi Ross,

Thanks for your response.

I'm not sure of the access mode for register 0xFE, as I do it under u-boot, use "MII read" and "MII write" command. I need to look into the code and feedback you shortly.

when reading and writing register 0-16, all return values are correct.

After writing register 0xFE, no response . "MII write 0xf 0xFE 0xE720"

Then change back to read register 0, no response too.

until we reset PHY, the communication is resumed.

Thanks.

0 Ross Pimentel over 7 years ago in reply to kent lu

TI__Mastermind 23675 points

Hi Kent,

Check to make sure you are using extended register access for that register.
This might be the issue.

0 Ross Pimentel over 7 years ago in reply to Ross Pimentel

TI__Mastermind 23675 points

Hi Kent,

Have you been able to check this?

0 kent lu over 7 years ago in reply to Ross Pimentel

Prodigy 230 points

Dear Ross,

Sorry for my delay. I set the registers by way of extended register access mode for MII loopback test, and find that RX/DX get no data package. I also test with another way by setting below registers, but failed too.

Address 0x0016 = 0x0004
Address 0x0000 = 0x0140
Address 0x001F = 0x4000

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Linux/DP83867IR: cannot complete MII loopback test