Re: [PATCH 2/4] can: flexcan: Detect error passive state change

[Alexander Stein <alexander.stein@systec-electronic.com>]

On Friday 15 August 2014 10:07:06, Marc Kleine-Budde wrote:
> On 08/12/2014 03:43 PM, Alexander Stein wrote:
> > Assuming there is no CAN frame reception or CAN_CTRLMODE_BERR_REPORTING:
> > If the Tx error counter steps from 127 to 128 the hardware enters error
> > passive. But in this case the FLEXCAN_ESR_ERR_STATE bits are unset:
> > TWRN_INT and RWRN_INT are not set during the transition from <96 to >=96.
> 
> Which hardware are you using? According to the documentation TWRN_INT
> and RWRN_INT _are_ actually set during the transition from <96 to >=96.

Meh, wrong case description... What I wanted to write:
TWRN_INT and RWRN_INT are _only_ set during the transition from <96 to >=96.
And for the records I'm using a i.MX35.

> > So we do not schedule NAPI thus not evaluating the error counters.
> > So we also check TX_WRN and RX_WRN in order to detect error passive.
> > 
> > Signed-off-by: Alexander Stein <alexander.stein@systec-electronic.com>
> > ---
> >  drivers/net/can/flexcan.c | 3 ++-
> >  1 file changed, 2 insertions(+), 1 deletion(-)
> > 
> > diff --git a/drivers/net/can/flexcan.c b/drivers/net/can/flexcan.c
> > index fd79dd40840b..5e391ec70a2b 100644
> > --- a/drivers/net/can/flexcan.c
> > +++ b/drivers/net/can/flexcan.c
> > @@ -721,7 +721,8 @@ static irqreturn_t flexcan_irq(int irq, void *dev_id)
> >  	 * - bus error IRQ and bus error reporting is activated
> >  	 */
> >  	if ((reg_iflag1 & FLEXCAN_IFLAG_RX_FIFO_AVAILABLE) ||
> > -	    (reg_esr & FLEXCAN_ESR_ERR_STATE) ||
> > +	    (reg_esr & (FLEXCAN_ESR_ERR_STATE |
> > +			FLEXCAN_ESR_TX_WRN | FLEXCAN_ESR_RX_WRN)) ||
> >  	    flexcan_has_and_handle_berr(priv, reg_esr)) {
> >  		/*
> >  		 * The error bits are cleared on read,
> > 
> 
> Marc
> 
> 

-- 
Dipl.-Inf. Alexander Stein

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