lkml.org 
[lkml]   [2011]   [Dec]   [10]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
Date
From
SubjectRe: [PATCH] flexcan: Acknowledge all interrupt sources in the IRQ handler
On 12/09/2011 03:35 PM, Wolfgang Grandegger wrote:
> On 12/09/2011 02:59 PM, Lothar Waßmann wrote:
>> Hi,
>>
>> Marc Kleine-Budde writes:
>>> On 12/09/2011 02:47 PM, Lothar Waßmann wrote:
>>>> Otherwise the handler will get stuck in an endless IRQ loop when an
>>>> interrupt condition occurs that is not being acked (e.g. TWRN)
>>>
>>> On which CPU do you have this problem?
>>>
>> on i.MX28.
>
> Yes, it is definitely needed on i.MX28 and I already have it in my
> series. See:
>
> https://gitorious.org/~wgrandegger/linux-can/wg-linux-can-next/commit/8ad94fa0dd7f7728824fa8fd4479390ac3f189c7
>
> BTW: at similar patch was already sent by Reuben Dowle.
>
>>> Seems that mx25/35 behave a bit different than mx28. But I had no time
>>> to dig into this, yet. BTW Wolfgang is just reworking error handling,
>>> can you please test his patches he recently posted on linux-can.
>>>
>> The ESR of i.MX25 is completely identical to the i.MX28.
>> You should be able to reproduce the problem when trying to send a
>> message to a CAN interface with the transceiver disabled.
>> You will get a BIT0_ERR and the TWRN bit will be asserted and never
>> cleared leading to an endless interrupt loop.
>
> If you are right, the code was never working on i.MX25/35... which I doubt.

I know remember that the old code was working on a MX35PDK board.
Actually I did the porting some time ago. That means that we have to
deal with two variants of the Flexcan controller, unfortunately:

mx25/35: State changes *and* bus errors are both signalled via ESR ERR
bit. The TWRN, RWRN and BOFF bits seem not to be used. Therefore
bus error reporting cannot be enabled/disabled individually.

mx28/mx53?: Bus error are signalled via ESR ERR bit and state changes
via TWRN, RWRN and BOFF bit. Therefore bus error reporting
*can* be enabled/disabled individually as implemented by this
patch:

https://gitorious.org/~wgrandegger/linux-can/wg-linux-can-next/commit/f0829d269a451c8abb99435d5a1a63cb18566668
I will try to get a MX35PDK board for further evaluation and development.

Wolfgang.

--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@vger.kernel.org
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/

\
 
 \ /
  Last update: 2011-12-10 21:13    [from the cache]
©2003-2011 Jasper Spaans