On 11/27/19 6:56 AM, Joakim Zhang wrote:
> From: Sean Nyekjaer <sean@xxxxxxxxxx>
>
> 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@xxxxxxxxxx>
> Signed-off-by: Joakim Zhang <qiangqing.zhang@xxxxxxx>
> ------
> 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 |
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