GRETH networking instability with L2C Lite enabled

General - Software
1

Hello,

We are experiencing a networking issue on our platform and would like to understand whether it could be related to cache coherency, DMA maintenance, or L2C Lite integration.

Our setup uses:

  • GRLIB 2024.4
  • 4 NOEL-V cores
  • GRETH Ethernet MAC
  • L2C Lite

On Linux 6.13 generated with Buildroot, we observe the following behavior:

  • During sustained SCP transfers from a host to the device, the network connection sometimes stalls or breaks.
  • Running:
    ip link set eth0 down
    ip link set eth0 up
    restores the connection immediately and the SCP transfer resumes normally.
  • In some cases, instead of recovering cleanly, the system ends in a kernel panic.
  • If we remove the L2C Lite and instead connect memory through a direct AHB-to-AXI bridge, the issue completely disappears.

This makes us suspect a cache coherency or DMA cache maintenance issue involving the L2C Lite.

Questions:

  1. Is the GRETH driver expected to handle cache coherency explicitly?
  2. Are there any known coherency limitations or considerations between GRETH DMA and L2C Lite?
  3. Could this behavior indicate an issue in the hardware integration or cache implementation?

Any guidance or known issues would be greatly appreciated.

Thank you,
Marc