On 12/3/19 6:25 PM, Marc Kleine-Budde wrote:
> 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.
Otherwise this patch is OK. With this patch the flexcan_suspend() and
flexcan_resume() look finally symmetric. \o/
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 |
Attachment:
signature.asc
Description: OpenPGP digital signature
