RGMII2 ping issue on AM4377 custom board

Krishna Prasad

Other Parts Discussed in Thread: AM4377

Hi,

I am working on AM4377 based custom board. Silicon version is 1.2.

Ethernet is working fine on RGMII1. Now I have trying to make ethernet up on RGMII2 port, I have done all required configuration.

"eth1" interface is listing up on ifconfig command. but ping is failing.

Following are my observations

1. In Wireshark I analyzed the packets. I found that some ARP broadcast packets are going from board. Also if I ping from Host PC, ARP response is going from the board. But ping response is not going.

2. ping is working on RGMII2 if I connect Ethernet cable to RGMII1 port and ping is stopping if I remove cable from RGMII1 port.

Let me know If I am missing any configuration and how ping is working if I connect ethernet cable to Port 1.

Thanks and Regards,

Krishna

over 8 years ago

0 Biser Gatchev-XID over 8 years ago

TI__Guru**** 393215 points

Hi,

This sounds like a hardware effect that has been observed on the AM335X Starter Kit. Can you check whether your second PHY is clocked from its own crystal, or uses clock from the first PHY? If this is the case, when you remove the cable from the first PHY it goes to sleep and clock to the second PHY is stopped.

0 Krishna Prasad over 8 years ago in reply to Biser Gatchev-XID

Intellectual 270 points

Hi Biser,

Thanks for the reply.

Each Phy in the board has its own crystal. There is no dependency on the clock from other phy . Also even when Ethernet cable to RGMII1 not connected, some of the TX (ARP packet) packet is going to Host PC. only ping is not working.

Thanks and Regards,
Krishna

0 Krishna Prasad over 8 years ago in reply to Krishna Prasad

Intellectual 270 points

Hi,

ping is working on both RGMII1 and RGMII2 (irrespective of RGMII1 connection/disconnection status) if both are connected in separate subnet(different lan segments). Issue is coming only when both RGMII1 and RGMII2 are connected in same network. Now with the working setup, I am observing ping loss (packet loss upto 40%) with RGMII2 port where as with RGMII1 there is no much ping loss.

What might be the reason for this?

Thanks and Regards
Krishna

0 Biser Gatchev-XID over 8 years ago in reply to Krishna Prasad

TI__Guru**** 393215 points

Hi,

This is a known constraint of the Linux Ethernet driver. See processors.wiki.ti.com/.../Linux_Core_CPSW_User's_Guide

0 Krishna Prasad over 8 years ago in reply to Biser Gatchev-XID

Intellectual 270 points

Hi Biser,

Thanks for the link. It was helpful.
Now I am checking ping loss issue in RGMII2 port when RGMII1 and RGMII2 connected in differnet subnet. Issue is coming even if I make RGMII1 link down.
We are pinging from Board to Host PC.
We analyzed in network packets in Wireshark and found that during Ping loss, ICMP Request packet itself is not getting captured.

What might be the issue?

Thanks and Regards,
Krishna

0 Biser Gatchev-XID over 8 years ago in reply to Krishna Prasad

TI__Guru**** 393215 points

Are you pinging from u-boot or kernel? which Linux version are you using?

0 Krishna Prasad over 8 years ago in reply to Biser Gatchev-XID

Intellectual 270 points

Hi Biser,

I am using Vxworks OS. Issue is there when we ping from Board side also when we ping from Host PC side.
The constraints shared in the link is specific to Linux OS or its a generic limitataion?

Regards,
Krishna

0 Biser Gatchev-XID over 8 years ago in reply to Krishna Prasad

TI__Guru**** 393215 points

The wiki link is valid for the Linux Ethernet driver. I cannot say about Vxworks, as this OS is not supported by TI.

Processors

Processors forum

RGMII2 ping issue on AM4377 custom board