DWC4 ethernet in U-Boot receiving it's own traffic

[Patrice CHOTARD]

Hi Marek

For this issue, can you contact the support by clicking on the "ST Support Center" link on this page: https://wiki.st.com/stm32mpu/wiki/Main_Page ?

Thanks

Patrice

On 1/28/20 10:32 PM, Marek Vasut wrote:
> Hi,
>
> are you aware of any issues with the DWC4 ethernet in U-Boot? I recently
> ran into oddity where the MAC receives it's own packets upon replying to
> ARP request.
>
> Test case is as follows:
> - Assume host PC with IP 192.168.1.1/24 ,
>   STM32MP1 board with IP 192.168.1.2/24
> - Assume TFTP server has 64MiB file called 64m full of zeroes
>   ($ dd if=/dev/zero of=/tftpboot/64m bs=64M count=1)
> - Run the following in U-Boot:
> $ setenv ipaddr 192.168.1.2
> $ setenv netmask 255.255.255.0
> $ setenv serverip 192.168.1.1
> $ tftp 192.168.1.1:64m
> - In parallel, during the TFTP transfer, run the following on PC:
> $ arping -c 1 192.168.1.2
>
> Observe 5-second delay while the MAC is trying to recover or complete
> failure of the transfer.
>
> What happens is that the U-Boot is in netloop, receives the ARP request
> and sends ARP reply. So far so good. However, the DWC4 receives that ARP
> reply too for reason that is not clear yet (the packet which arrives in
> eqos_recv() has source MAC equal to the board MAC address).
>
> Note that this is modeling a real world scenario where the host PC sends
> ARP request to the board during a TFTP transfer. The same problem does
> happen then.
>
> Can you try replicating this and see whether this is happening for you too?
>