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

[Marc Kleine-Budde <mkl@pengutronix.de>]

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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.

> 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

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