From: Marc Kleine-Budde <mkl@pengutronix.de>
To: Joakim Zhang <qiangqing.zhang@nxp.com>,
"sean@geanix.com" <sean@geanix.com>,
"linux-can@vger.kernel.org" <linux-can@vger.kernel.org>
Cc: dl-linux-imx <linux-imx@nxp.com>,
"netdev@vger.kernel.org" <netdev@vger.kernel.org>
Subject: Re: [PATCH V2 1/4] can: flexcan: fix deadlock when using self wakeup
Date: Tue, 3 Dec 2019 18:25:08 +0100 [thread overview]
Message-ID: <b77829d5-9eda-a244-3ee8-2ccdbdfb6524@pengutronix.de> (raw)
In-Reply-To: <20191127055334.1476-2-qiangqing.zhang@nxp.com>
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On 11/27/19 6:56 AM, Joakim Zhang wrote:
> From: Sean Nyekjaer <sean@geanix.com>
>
> When suspending, when there is still can traffic on the interfaces the
> flexcan immediately wakes the platform again. As it should :-). But it
> throws this error msg:
> [ 3169.378661] PM: noirq suspend of devices failed
>
> On the way down to suspend the interface that throws the error message does
> call flexcan_suspend but fails to call flexcan_noirq_suspend. That means the
> flexcan_enter_stop_mode is called, but on the way out of suspend the driver
> only calls flexcan_resume and skips flexcan_noirq_resume, thus it doesn't call
> flexcan_exit_stop_mode. This leaves the flexcan in stop mode, and with the
> current driver it can't recover from this even with a soft reboot, it requires
> a hard reboot.
>
> This patch can fix deadlock when using self wakeup, it happenes to be
> able to fix another issue that frames out-of-order in first IRQ handler
> run after wakeup.
>
> In wakeup case, after system resume, frames received out-of-order in
> first IRQ handler, the problem is wakeup latency from frame reception to
> IRQ handler is much bigger than the counter overflow. This means it's
> impossible to sort the CAN frames by timestamp. The reason is that controller
> exits stop mode during noirq resume, then it can receive the frame immediately.
> If noirq reusme stage consumes much time, it will extend interrupt response
> time. So exit stop mode during resume stage instead of noirq resume can
> fix this issue.
>
> Fixes: de3578c198c6 ("can: flexcan: add self wakeup support")
> Signed-off-by: Sean Nyekjaer <sean@geanix.com>
> Signed-off-by: Joakim Zhang <qiangqing.zhang@nxp.com>
> ------
> ChangeLog:
> V1->V2: no change.
> ---
> 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(®s->esr);
>
> + /* ACK wakeup interrupt */
> + if (reg_esr & FLEXCAN_ESR_WAK_INT) {
> + handled = IRQ_HANDLED;
> + priv->write(reg_esr & FLEXCAN_ESR_WAK_INT, ®s->esr);
> + }
> +
If FLEXCAN_ESR_WAK_INT stays in FLEXCAN_ESR_ALL_INT, you don't need that
explicit ACK here.
Marc
--
Pengutronix e.K. | Marc Kleine-Budde |
Embedded Linux | https://www.pengutronix.de |
Vertretung West/Dortmund | Phone: +49-231-2826-924 |
Amtsgericht Hildesheim, HRA 2686 | Fax: +49-5121-206917-5555 |
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next prev parent reply other threads:[~2019-12-03 17:25 UTC|newest]
Thread overview: 43+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-11-27 5:56 [PATCH V2 0/4] can: flexcan: fixes for stop mode Joakim Zhang
2019-11-27 5:56 ` [PATCH V2 1/4] can: flexcan: fix deadlock when using self wakeup Joakim Zhang
2019-11-27 9:58 ` Sean Nyekjaer
2019-12-03 17:25 ` Marc Kleine-Budde [this message]
2019-12-03 17:42 ` Marc Kleine-Budde
2019-12-04 1:58 ` Joakim Zhang
2019-12-04 8:31 ` Marc Kleine-Budde
2019-12-04 8:35 ` Joakim Zhang
2019-11-27 5:56 ` [PATCH V2 2/4] can: flexcan: try to exit stop mode during probe stage Joakim Zhang
2019-11-27 9:58 ` Sean Nyekjaer
2019-12-03 18:14 ` Marc Kleine-Budde
2019-12-04 2:22 ` Joakim Zhang
2019-12-04 8:45 ` Marc Kleine-Budde
2019-12-04 9:58 ` Joakim Zhang
2019-12-05 8:46 ` Joakim Zhang
2019-12-05 9:21 ` Sean Nyekjaer
2019-12-05 11:04 ` Joakim Zhang
2019-12-05 11:11 ` Sean Nyekjaer
2019-12-05 11:19 ` Joakim Zhang
2019-12-05 11:32 ` Sean Nyekjaer
2019-12-07 20:32 ` Marc Kleine-Budde
2019-12-08 10:47 ` Sean Nyekjaer
2019-12-08 10:56 ` Marc Kleine-Budde
2019-11-27 5:56 ` [PATCH V2 3/4] can: flexcan: change the way of stop mode acknowledgment Joakim Zhang
2019-11-27 9:58 ` Sean Nyekjaer
2019-12-03 18:21 ` Marc Kleine-Budde
2019-12-04 2:23 ` Joakim Zhang
2019-11-27 5:56 ` [PATCH V2 4/4] can: flexcan: add LPSR mode support Joakim Zhang
2019-12-04 2:25 ` Joakim Zhang
2019-12-04 8:59 ` Marc Kleine-Budde
2019-12-04 9:58 ` Joakim Zhang
2019-12-04 9:20 ` Marc Kleine-Budde
2019-12-04 9:59 ` Joakim Zhang
2019-12-04 10:58 ` Joakim Zhang
2019-11-27 6:12 ` [PATCH V2 0/4] can: flexcan: fixes for stop mode Sean Nyekjaer
2019-11-27 8:12 ` Sean Nyekjaer
2019-11-27 9:36 ` Joakim Zhang
2019-11-27 9:48 ` Joakim Zhang
2019-11-27 9:52 ` Sean Nyekjaer
2019-11-27 9:58 ` Joakim Zhang
2019-11-27 9:59 ` Sean Nyekjaer
2019-11-27 10:04 ` Joakim Zhang
2019-12-03 10:16 ` Joakim Zhang
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