From mboxrd@z Thu Jan  1 00:00:00 1970
Message-ID: <52DFAA18.6080703@xenomai.org>
Date: Wed, 22 Jan 2014 12:23:04 +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 11:24 AM, Alexandre COFFIGNAL wrote:
> Hi all,
> 
> I use two rtcan flexcan on imx28-evk board.
> 
> If both rtcan devices receive a data at the same time, this cause a freeze.
> After investigation, i found that if I replace in flexcan_rx_interrupt 
> these instructions :
> -        *(__be32 *)(cf->data + 0) =
> -            cpu_to_be32(flexcan_read(&mb->data[0]));
> -        *(__be32 *)(cf->data + 4) =
> -            cpu_to_be32(flexcan_read(&mb->data[1]));
> 
> by these
> 
> +        data0 = flexcan_read(&mb->data[0]);
> +        data1 = flexcan_read(&mb->data[1]);
> +
> +        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.


-- 
                                                                Gilles.