Messages in this thread |  | | Date | Sat, 10 Dec 2011 21:10:28 +0100 | | From | Wolfgang Grandegger <> | | Subject | Re: [PATCH] flexcan: Acknowledge all interrupt sources in the IRQ handler |
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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.
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