netdev - RE: [PATCH V2 1/4] can: flexcan: fix deadlock when using self wakeup

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Date:   Wed, 4 Dec 2019 01:58:24 +0000
From:   Joakim Zhang <qiangqing.zhang@....com>
To:     Marc Kleine-Budde <mkl@...gutronix.de>,
        "sean@...nix.com" <sean@...nix.com>,
        "linux-can@...r.kernel.org" <linux-can@...r.kernel.org>
CC:     dl-linux-imx <linux-imx@....com>,
        "netdev@...r.kernel.org" <netdev@...r.kernel.org>
Subject: RE: [PATCH V2 1/4] can: flexcan: fix deadlock when using self wakeup


> -----Original Message-----
> From: Marc Kleine-Budde <mkl@...gutronix.de>
> Sent: 2019年12月4日 1:25
> To: Joakim Zhang <qiangqing.zhang@....com>; sean@...nix.com;
> linux-can@...r.kernel.org
> Cc: dl-linux-imx <linux-imx@....com>; netdev@...r.kernel.org
> Subject: Re: [PATCH V2 1/4] can: flexcan: fix deadlock when using self wakeup

[...]
> >  drivers/net/can/flexcan.c | 19 +++++++++++--------
> >  1 file changed, 11 insertions(+), 8 deletions(-)
> >
> > diff --git a/drivers/net/can/flexcan.c b/drivers/net/can/flexcan.c
> > index 2efa06119f68..2297663cacb2 100644
> > --- a/drivers/net/can/flexcan.c
> > +++ b/drivers/net/can/flexcan.c
> > @@ -134,8 +134,7 @@
> >  	(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_ESR_WAK_INT)
> > +	 FLEXCAN_ESR_BOFF_INT | FLEXCAN_ESR_ERR_INT)
> 
> Why do you remove the FLEXCAN_ESR_WAK_INT from the
> FLEXCAN_ESR_ALL_INT?
> 
> >
> >  /* FLEXCAN interrupt flag register (IFLAG) bits */
> >  /* Errata ERR005829 step7: Reserve first valid MB */ @@ -960,6
> > +959,12 @@ static irqreturn_t flexcan_irq(int irq, void *dev_id)
> >
> >  	reg_esr = priv->read(&regs->esr);
> >
> > +	/* ACK wakeup interrupt */
> > +	if (reg_esr & FLEXCAN_ESR_WAK_INT) {
> > +		handled = IRQ_HANDLED;
> > +		priv->write(reg_esr & FLEXCAN_ESR_WAK_INT, &regs->esr);
> > +	}
> > +
> 
> If FLEXCAN_ESR_WAK_INT stays in FLEXCAN_ESR_ALL_INT, you don't need
> that explicit ACK here.

Hi Marc,

I remove the FLEXCAN_ESR_WAK_INT from the FLEXCAN_ESR_ALL_INT since FLEXCAN_ESR_ALL_INT is for
all bus error and state change IRQ sources, wakeup interrupt does not belong to these. If you think this does
not need, I can remove this change.

Best Regards,
Joakim Zhang
> Marc
> 
> --
> Pengutronix e.K.                 | Marc Kleine-Budde           |
> Embedded Linux                   | https://www.pengutronix.de  |
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