How does NDK handle Ethernet link down?

Hi Steve,

Thanks for replying and for entering the bug report.  Reading the PHY management register is indeed working for me to determine link status.  For the 2nd part of my question, do you have recommendations on how to reset NDK when link down is detected?  All of the NDK initialization and startup is handled by generated configuration code rather than application code so this is the first time I've had to deal with it.  I've reviewed the NDK documentation and found NC_NetStart and NC_NetStop functions.  I'm planning to try these out today.  Let me know if there is a better option.

Thanks,

Lance

Hi Steve,

Hopefully you are still following this thread.  I'll post a new topic if I don't hear from you.

I'm having an issue stopping and restarting NDK.  I didn't notice this before because I had disabled most debug printf statements in NDK but I turned them back on and discovered this issue.

The problem occurs after NC_NetStop() is called and eventually invokes a shutdown.  When NIMUShutdown() is processing the list of devices (nimu_mcb.devices) it removes the node from the list and then calls mmfree() on the ptr.  This mmfree() call results in a "mmFree: double free" error message out of the memory manager.  I looked into this further and found out that the actual cause of this problem is that in the file packages\ti\drivers\EMAC.c in the function EMAC_NIMUInit() a statically allocated device is passed to the function NIMURegister().

From EMAC.c - EMAC_NIMUInit():

/* Register the device with NIMU */
 if (NIMURegister(&EMAC_device) < 0) {
     Log_print0(Diags_USER1, "EMAC: failed to register with NIMU");
     return (-1);
 }

So when mmFree casts that pointer to a MEMORYBLOCK structure it ends up pointing into some other data structure and thinks that the BUSY flag is not set for that block.

I know how to fix this by using mmAlloc() to create EMAC_device rather than using statically allocated memory, but the problem is I have no idea how to rebuild EMAC.c.  I've tried re-building both the NDK and StellarisWare with a forced compiler error in that file, but neither of those builds seem to include that file.  Is this part of the SYSBIOS build?  If so, how do I rebuild it?

I greatly appreciate your continued support.

Lance

Lance,

This is a bug in the driver.

Good news is that it's already been fixed, but that means you would need to upgrade to a newer version of TI-RTOS (note that MCUSDK has had a name change and the product is now known as TI-RTOS).

I see that it's fixed in version TIRTOS 1_01_00_25.  You can find that version on the TI-RTOS download page.

Note also that this is not the latest version on that download page.  You need to download this slightly older version because support for the LM3S9B92 has been dropped in TI-RTOS 1.10.00.23 (and future releases).  From the 1.10.00.23 release notes:

"Support for LM3 devices has been discontinued. If required a patch release off the 1.01 release can be made."

Steve

Thanks for the excellent support Steve.  I've made a note of that version of code for my next project, but I have just hacked around the problem for now to keep myself on schedule.

Lance

Hi Steve,

I have the same problem, when I unplug the ethernet link I can't manage to make an http get. I want to restart the interface but can't manage to find where the NC_NetStop function is located, what header do I need to include ?

Thank you in advance,

Best Regards,