Cache issue with BBB networking

Daniel Gutson daniel.gutson at tallertechnologies.com
Tue Jun 30 03:46:47 UTC 2015


Ragu,

   Please ensure that you are getting cache coherence right. That is, there
are no packets crossing the cache lines.
FWIW, in a life ago, i got a problem with an eth driver where the
descriptors ring was not properly sized (ie no modulus cache line).
El 29/6/2015 17:23, "ragu nath" <ragunath3252 at gmail.com> escribió:

> Thanks Marcos. I will let you know if there is any progress.
>
> Regards,
> Ragunath
>
> On Tue, Jun 30, 2015 at 12:50 AM, Marcos Díaz <
> marcos.diaz at tallertechnologies.com> wrote:
>
>> Hi,
>> I'm sorry but in the development of the porting of LWIP i couldn't give
>> any more time to the task, so when I reached that stage I just disabled the
>> cache.
>> I will try to give some time to that to see if i can help you, and of
>> course, let me know if you find something.
>> Sorry again
>>
>> On Mon, Jun 29, 2015 at 3:16 PM, ragu nath <ragunath3252 at gmail.com>
>> wrote:
>>
>>> Hi Marcos,
>>>
>>> I am working on porting ethernet driver for Beaglebone black from
>>> FreeBSD to rtems-libbsd as part of GSOC 2015. I ported the driver and
>>> got it working.
>>>
>>> But there was one issue I faced, similar to the one you mentioned in
>>> our earlier correspondence (regarding lwIP). You mentioned that the
>>> system crashes if cache is enabled.
>>>
>>> In my case, the Address Lookup Engine (ALE) is getting corrupted if
>>> cache is enabled. Because of this packet transmission failed sending
>>> out random junk packets. With cache disabled, networking is working.
>>>
>>> I am looking for options other than disabling cache as a whole. Is
>>> there any other option available?  Can you share the details of any of
>>> the things you tried and found not working?
>>>
>>>
>>> Thanks,
>>> Ragunath
>>>
>>
>>
>>
>> --
>>
>> ______________________________
>>
>> <http://www.tallertechnologies.com>
>>
>>
>> Marcos Díaz
>>
>> Software Engineer
>>
>>
>> San Lorenzo 47, 3rd Floor, Office 5
>>
>> Córdoba, Argentina
>>
>>
>> Phone: +54 351 4217888 / +54 351 4218211/ +54 351 7617452
>>
>> Skype: markdiaz22
>>
>>
>
>
> --
> ragu
>
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