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Date: Wed, 22 Jan 2014 15:12:00 +0100
From: Gilles Chanteperdrix <gilles.chanteperdrix@xenomai.org>
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Subject: Re: [Xenomai] imx28 rtcan flexcan system freezes
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To: Alexandre COFFIGNAL <acoffignal@geral.com>
Cc: xenomai@xenomai.org

On 01/22/2014 03:04 PM, Alexandre COFFIGNAL wrote:
>
> Le 22/01/2014 14:30, Gilles Chanteperdrix a écrit :
>> On 01/22/2014 02:27 PM, Alexandre COFFIGNAL wrote:
>>>
>>> Le 22/01/2014 13:00, Gilles Chanteperdrix a écrit :
>>>> On 01/22/2014 12:36 PM, Alexandre COFFIGNAL wrote:
>>>>>>> +        cf->data[3]=((data0 >> 0)  & 0xFF) ;
>>>>>>> +        cf->data[2]=((data0 >> 8)  & 0xFF) ;
>>>>>>> +        cf->data[1]=((data0 >> 16)  & 0xFF) ;
>>>>>>> +        cf->data[0]=((data0 >> 24)  & 0xFF) ;
>>>>>>> +        cf->data[7]=((data1 >> 0)  & 0xFF) ;
>>>>>>> +        cf->data[6]=((data1 >> 8)  & 0xFF) ;
>>>>>>> +        cf->data[5]=((data1 >> 16)  & 0xFF) ;
>>>>>>> +        cf->data[4]=((data1 >> 24)  & 0xFF) ;
>>>>>>>
>>>>>>> rtcan flexcan works perfectly.
>>>>>>> is  anyone know what is the problem with first instructions ?
>>>>>> Probably mb->data does not have the right alignment. Could you not
>>>>>> arrange to get it properly aligned? Failing that, you should use
>>>>>> put_unaligned instead of open coding it.
>>>>>>
>>>>>>
>>>>> here structures used in flexcan driver, it seem to be aligned
>>>>
>>>> I am talking about the alignment of cf->data, since obviously, that is
>>>> the one which is causing problems.
>>>>
>>>>
>>> Thank a lot, put_unaligned fix this issue if you want, i can send a path
>>>
>>
>> The other solution (getting cf->data to be properly aligned) would be
>> more efficient, why is not it possible to get cf->data properly aligned?
>>
> I think, i can't get cf->data to be properly aligned because "cf" is
> receive internal frame representation within the ring buffer
> of a struct rtcan_socket and struct rtcan_rb_frame is a generic
> structure used in all rtcan drivers .

Well, if you fix rtcan_rb_frame to be aligned, it will be aligned for 
all drivers, so that looks like a worthwile improvement...


-- 
					    Gilles.