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Date: Mon, 12 Dec 2011 16:31:09 +0100
From: Marc Kleine-Budde <mkl@...gutronix.de>
To: Wolfgang Grandegger <wg@...ndegger.com>
CC: netdev@...r.kernel.org, linux-can@...r.kernel.org,
Reuben Dowle <Reuben.Dowle@...ico.com>,
Lothar Waßmann <LW@...O-electronics.de>
Subject: Re: [PATCH] can: flexcan: fix irq flooding by clearing all interrupt
sources
On 12/12/2011 04:09 PM, Wolfgang Grandegger wrote:
> As pointed out by Reuben Dowle and Lothar Waßmann, the TWRN_INT,
> RWRN_INT, BOFF_INT interrupt sources need to be cleared as well
> to avoid interrupt flooding, at least for the Flexcan on i.MX28
> SOCs. Furthermore, the interrupts are only cleared, if really one
> of those interrupt sources are pending (which is not the case for
> rx and tx done).
>
> CC: Reuben Dowle <Reuben.Dowle@...ico.com>
> CC: Lothar Waßmann <LW@...O-electronics.de>
> Signed-off-by: Wolfgang Grandegger <wg@...ndegger.com>
Have you tested on mx25/mx35, does it have any negative side effects?
My schedule is full until Friday, sorry cannot test here.
Marc
> ---
> drivers/net/can/flexcan.c | 7 ++++++-
> 1 files changed, 6 insertions(+), 1 deletions(-)
>
> diff --git a/drivers/net/can/flexcan.c b/drivers/net/can/flexcan.c
> index 165a4c7..111f154 100644
> --- a/drivers/net/can/flexcan.c
> +++ b/drivers/net/can/flexcan.c
> @@ -118,6 +118,9 @@
> (FLEXCAN_ESR_TWRN_INT | FLEXCAN_ESR_RWRN_INT | FLEXCAN_ESR_BOFF_INT)
> #define FLEXCAN_ESR_ERR_ALL \
> (FLEXCAN_ESR_ERR_BUS | FLEXCAN_ESR_ERR_STATE)
> +#define FLEXCAN_ESR_ALL_INT \
> + (FLEXCAN_ESR_TWRN_INT | FLEXCAN_ESR_RWRN_INT | \
> + FLEXCAN_ESR_BOFF_INT | FLEXCAN_ESR_ERR_INT)
>
> /* FLEXCAN interrupt flag register (IFLAG) bits */
> #define FLEXCAN_TX_BUF_ID 8
> @@ -577,7 +580,9 @@ static irqreturn_t flexcan_irq(int irq, void *dev_id)
>
> reg_iflag1 = flexcan_read(®s->iflag1);
> reg_esr = flexcan_read(®s->esr);
> - flexcan_write(FLEXCAN_ESR_ERR_INT, ®s->esr); /* ACK err IRQ */
> + /* ACK all bus error and state change IRQ sources */
> + if (reg_esr & FLEXCAN_ESR_ALL_INT)
> + flexcan_write(reg_esr & FLEXCAN_ESR_ALL_INT, ®s->esr);
>
> /*
> * schedule NAPI in case of:
--
Pengutronix e.K. | Marc Kleine-Budde |
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