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Altera_Forum
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14 years ago

Linux with MMU on Neek: incorrect UDP/TCP cheksum

Hello everyone!

Recently I started working on a project of bringing Linux with MMU on Neek board.

I have working system using nios2-linux-20100621.tar uClinux distribution,

and neek_ocm_spi_mmu.zip design.

I select "OpenCores 10/100 Mbps Ethernet MAC support" (ETHOC) and

succeed in passing ping. But anything except ping fails. It turned out that all packets

transmitted by Neek have bad Layer4 (UDP/TCP) checksum. Looking through ethoc.c source

I cannot find anything like "TCP checksum offload" which might cause such problem.

OpenCores Ethernet MAC spec also does not state anything related to such offload.

Does anyone has an idea what may cause such incorrect Layer 4 checksumming?

Thanks,

Vladik

4 Replies

  • Altera_Forum's avatar
    Altera_Forum
    Icon for Honored Contributor rankHonored Contributor
    14 years ago

    Hi Vladik,

    is this you first project with the Opencores MAC on the board or have you had success with other than linux, i.e. the webserver example from interniche inside the nios ide?

    Have you tried the other driver "Opencores (igor MAC)"?

    Urmel
  • Altera_Forum's avatar
    Altera_Forum
    Icon for Honored Contributor rankHonored Contributor
    14 years ago

    I had a checksum problem some times ago. The kernel I was using was bugged....

    This is from the mail list:

    --- Quote Start ---

    There was an error in the NIOS II optimized checksum implementation that was

    fixed after 2.6.34. Other people ran into the problem here:

    http://www.alteraforum.com/forum/showthread.php?t=24075

    --- Quote End ---

    May be it can help you.
  • Altera_Forum's avatar
    Altera_Forum
    Icon for Honored Contributor rankHonored Contributor
    14 years ago

    --- Quote Start ---

    Hi Vladik,

    is this you first project with the Opencores MAC on the board or have you had success with other than linux, i.e. the webserver example from interniche inside the nios ide?

    Have you tried the other driver "Opencores (igor MAC)"?

    Urmel

    --- Quote End ---

    Hi Urmel,

    this is my 1st project with Opencores MAC. I didn't test Opencores (igor) MAC with this design.

    Vladik
  • Altera_Forum's avatar
    Altera_Forum
    Icon for Honored Contributor rankHonored Contributor
    14 years ago

    --- Quote Start ---

    I had a checksum problem some times ago. The kernel I was using was bugged....

    This is from the mail list:

    May be it can help you.

    --- Quote End ---

    You are absolutely correct: updating the kernel to 2.6.35 fixed all problems. Thank you!