[PATCH REPOST 0/2] can: flexcan: fix PM and wakeup issue

[PATCH REPOST 0/2] can: flexcan: fix PM and wakeup issue

[Joakim Zhang]

This patch set intends to fix Flecan PM and wakeup issue.

Joakim Zhang (2):
  can: flexcan: fix deadlock when using self wakeup
  can: flexcan: add LPSR mode support for i.MX7D

 drivers/net/can/flexcan.c | 34 ++++++++++++++++++++++++++++++----
 1 file changed, 30 insertions(+), 4 deletions(-)

-- 
2.17.1

[PATCH REPOST 1/2] can: flexcan: fix deadlock when using self wakeup

[Joakim Zhang]

As reproted by Sean Nyekjaer below:
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.

The best way to exit stop mode is in Wake Up interrupt context, and then
suspend() and resume() functions can be symmetric. However, stop mode
request and ack will be controlled by SCU(System Control Unit) firmware(manage
clock,power,stop mode, etc. by Cortex-M4 core) in coming i.MX8(QM/QXP). And SCU
firmware interface can't be available in interrupt context.

For compatibillity, the wake up mechanism can't be symmetric, so we need
in_stop_mode hack.

Fixes: de3578c198c6 ("can: flexcan: add self wakeup support")
Reported-by: Sean Nyekjaer <sean@geanix.com>
Signed-off-by: Joakim Zhang <qiangqing.zhang@nxp.com>

Changelog:
V1->V2:
	* add Reported-by tag.
	* rebase on patch: can:flexcan:fix stop mode acknowledgment.
V2->V3:
	* move into a patch set.
---
 drivers/net/can/flexcan.c | 23 +++++++++++++++++++++++
 1 file changed, 23 insertions(+)

diff --git a/drivers/net/can/flexcan.c b/drivers/net/can/flexcan.c
index 56fa98d7aa90..de2bf71b335b 100644
--- a/drivers/net/can/flexcan.c
+++ b/drivers/net/can/flexcan.c
@@ -282,6 +282,7 @@ struct flexcan_priv {
 	const struct flexcan_devtype_data *devtype_data;
 	struct regulator *reg_xceiver;
 	struct flexcan_stop_mode stm;
+	bool in_stop_mode;
 
 	/* Read and Write APIs */
 	u32 (*read)(void __iomem *addr);
@@ -1636,6 +1637,8 @@ static int __maybe_unused flexcan_suspend(struct device *device)
 			err = flexcan_enter_stop_mode(priv);
 			if (err)
 				return err;
+
+			priv->in_stop_mode = true;
 		} else {
 			err = flexcan_chip_disable(priv);
 			if (err)
@@ -1660,6 +1663,15 @@ static int __maybe_unused flexcan_resume(struct device *device)
 		netif_device_attach(dev);
 		netif_start_queue(dev);
 		if (device_may_wakeup(device)) {
+			if (priv->in_stop_mode) {
+				flexcan_enable_wakeup_irq(priv, false);
+				err = flexcan_exit_stop_mode(priv);
+				if (err)
+					return  err;
+
+				priv->in_stop_mode = false;
+			}
+
 			disable_irq_wake(dev->irq);
 		} else {
 			err = flexcan_chip_enable(priv);
@@ -1675,6 +1687,11 @@ static int __maybe_unused flexcan_noirq_suspend(struct device *device)
 	struct net_device *dev = dev_get_drvdata(device);
 	struct flexcan_priv *priv = netdev_priv(dev);
 
+	/* Need to enable wakeup interrupt in noirq suspend stage. Otherwise,
+	 * it will trigger continuously wakeup interrupt if the wakeup event
+	 * comes before noirq suspend stage, and simultaneously it has enter
+	 * the stop mode.
+	 */
 	if (netif_running(dev) && device_may_wakeup(device))
 		flexcan_enable_wakeup_irq(priv, true);
 
@@ -1687,11 +1704,17 @@ static int __maybe_unused flexcan_noirq_resume(struct device *device)
 	struct flexcan_priv *priv = netdev_priv(dev);
 	int err;
 
+	/* Need to exit stop mode in noirq resume stage. Otherwise, it will
+	 * trigger continuously wakeup interrupt if the wakeup event comes,
+	 * and simultaneously it has still in stop mode.
+	 */
 	if (netif_running(dev) && device_may_wakeup(device)) {
 		flexcan_enable_wakeup_irq(priv, false);
 		err = flexcan_exit_stop_mode(priv);
 		if (err)
 			return err;
+
+		priv->in_stop_mode = false;
 	}
 
 	return 0;
-- 
2.17.1

Re: [PATCH REPOST 1/2] can: flexcan: fix deadlock when using self wakeup

[Sean Nyekjaer]

On 16/08/2019 10.20, Joakim Zhang wrote:
> As reproted by Sean Nyekjaer below:
> 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.
> 
> The best way to exit stop mode is in Wake Up interrupt context, and then
> suspend() and resume() functions can be symmetric. However, stop mode
> request and ack will be controlled by SCU(System Control Unit) firmware(manage
> clock,power,stop mode, etc. by Cortex-M4 core) in coming i.MX8(QM/QXP). And SCU
> firmware interface can't be available in interrupt context.
> 
> For compatibillity, the wake up mechanism can't be symmetric, so we need
> in_stop_mode hack.
> 
> Fixes: de3578c198c6 ("can: flexcan: add self wakeup support")
> Reported-by: Sean Nyekjaer <sean@geanix.com>
> Signed-off-by: Joakim Zhang <qiangqing.zhang@nxp.com>
> 

Unfortunatly it's still possible to reproduce the deadlock with this 
patch...

[  689.921717] flexcan: probe of 2094000.flexcan failed with error -110

My test setup:
PC with CAN-USB dongle connected to can0 and can1.

PC:
$ while true; do cansend can0 '123#DEADBEEF'; done

iMX6ull:
root@iwg26:~# systemctl suspend 
 

[  365.858054] systemd[1]: Reached target Sleep.
root@iwg26:~# [  365.939826] systemd[1]: Starting Suspend...
[  366.115839] systemd-sleep[248]: Suspending system...
[  366.517949] dpm_run_callback(): platform_pm_suspend+0x0/0x5c returns -110
[  366.518249] PM: Device 2094000.flexcan failed to suspend: error -110
[  366.518406] PM: Some devices failed to suspend, or early wake event 
detected
[  366.732162] dpm_run_callback(): platform_pm_suspend+0x0/0x5c returns -110
[  366.732285] PM: Device 2090000.flexcan failed to suspend: error -110
[  366.732330] PM: Some devices failed to suspend, or early wake event 
detected
[  366.890637] systemd-sleep[248]: System resumed.
[  366.923062] systemd[1]: Started Suspend.
[  366.942819] systemd[1]: sleep.target: Unit not needed anymore. Stopping.
[  366.954791] systemd[1]: Stopped target Sleep.
[  366.962402] systemd[1]: Reached target Suspend.
[  366.977546] systemd-logind[135]: Operation 'sleep' finished.
[  366.979194] systemd[1]: suspend.target: Unit not needed anymore. 
Stopping.
[  366.993831] systemd[1]: Stopped target Suspend.
[  367.139972] systemd-networkd[220]: usb0: Lost carrier
[  367.294077] systemd-networkd[220]: usb0: Gained carrier

root@iwg26:~# candump can0 | head -n 2 

   can0  123   [4]  DE AD BE EF
   can0  123   [4]  DE AD BE EF
root@iwg26:~# candump can1 | head -n 2 

   can1  123   [4]  DE AD BE EF
   can1  123   [4]  DE AD BE EF
root@iwg26:~# systemctl suspend 

root@iwg26:~# [  385.106658] systemd[1]: Reached target Sleep.
[  385.147602] systemd[1]: Starting Suspend...
[  385.246421] systemd-sleep[260]: Suspending system...
[  385.634733] dpm_run_callback(): platform_pm_suspend+0x0/0x5c returns -110
[  385.634855] PM: Device 2090000.flexcan failed to suspend: error -110
[  385.634897] PM: Some devices failed to suspend, or early wake event 
detected
[  385.856251] PM: noirq suspend of devices failed
[  385.998364] systemd-sleep[260]: System resumed.
[  386.023390] systemd[1]: Started Suspend.
[  386.031570] systemd[1]: sleep.target: Unit not needed anymore. Stopping.
[  386.055886] systemd[1]: Stopped target Sleep.
[  386.061430] systemd[1]: Reached target Suspend.
[  386.066142] systemd[1]: suspend.target: Unit not needed anymore. 
Stopping.
[  386.112575] systemd-networkd[220]: usb0: Lost carrier
[  386.116797] systemd-logind[135]: Operation 'sleep' finished.
[  386.146161] systemd[1]: Stopped target Suspend.
[  386.260866] systemd-networkd[220]: usb0: Gained carrier
root@iwg26:~# candump can0 | head -n 2
   can0  123   [4]  DE AD BE EF
   can0  123   [4]  DE AD BE EF
root@iwg26:~# candump can1 | head -n 2 

   can1  123   [4]  DE AD BE EF
   can1  123   [4]  DE AD BE EF
root@iwg26:~# systemctl suspend 

[  396.919303] systemd[1]: Reached target Sleep.
root@iwg26:~# [  396.964722] systemd[1]: Starting Suspend...
[  397.067336] systemd-sleep[268]: Suspending system...
[  397.574571] PM: noirq suspend of devices failed
[  397.834731] PM: noirq suspend of devices failed
[  397.807996] systemd-networkd[220]: usb0: Lost carrier
[  398.156295] dpm_run_callback(): platform_pm_suspend+0x0/0x5c returns -110
[  398.156339] PM: Device 2094000.flexcan failed to suspend: error -110
[  398.156509] PM: Some devices failed to suspend, or early wake event 
detected
[  398.053555] systemd-sleep[268]: Failed to write /sys/power/state: 
Device or resource busy
[  398.074751] systemd[1]: systemd-suspend.service: Main process exited, 
code=exited, status=1/FAILURE
[  398.076779] systemd[1]: systemd-suspend.service: Failed with result 
'exit-code'.
[  398.109255] systemd[1]: Failed to start Suspend.
[  398.118704] systemd[1]: Dependency failed for Suspend.
[  398.136283] systemd-logind[135]: Operation 'sleep' finished.
[  398.137770] systemd[1]: suspend.target: Job suspend.target/start 
failed with result 'dependency'.
[  398.139105] systemd[1]: sleep.target: Unit not needed anymore. Stopping.
[  398.167590] systemd[1]: Stopped target Sleep.
[  398.201558] systemd-networkd[220]: usb0: Gained carrier

root@iwg26:~# candump can0 | head -n 2
   can0  123   [4]  DE AD BE EF
   can0  123   [4]  DE AD BE EF
root@iwg26:~# candump can1 | head -n 2

nothing on can1 anymore :-(

root@iwg26:~# rmmod flexcan
[  622.884746] systemd-networkd[220]: can1: Lost carrier
[  623.046766] systemd-networkd[220]: can0: Lost carrier
root@iwg26:~# insmod /mnt/flexcan.ko
[  628.323981] flexcan 2094000.flexcan: registering netdev failed

and can1 fails to register with:
[  628.347485] flexcan: probe of 2094000.flexcan failed with error -110

/Sean

RE: [PATCH REPOST 1/2] can: flexcan: fix deadlock when using self wakeup

[Joakim Zhang]

> -----Original Message-----
> From: Sean Nyekjaer <sean@geanix.com>
> Sent: 2019年8月20日 18:25
> To: Joakim Zhang <qiangqing.zhang@nxp.com>; mkl@pengutronix.de;
> linux-can@vger.kernel.org
> Cc: wg@grandegger.com; netdev@vger.kernel.org; dl-linux-imx
> <linux-imx@nxp.com>; Martin Hundebøll <martin@geanix.com>
> Subject: Re: [PATCH REPOST 1/2] can: flexcan: fix deadlock when using self
> wakeup
> 
> 
> 
> On 16/08/2019 10.20, Joakim Zhang wrote:
> > As reproted by Sean Nyekjaer below:
> > 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.
> >
> > The best way to exit stop mode is in Wake Up interrupt context, and
> > then
> > suspend() and resume() functions can be symmetric. However, stop mode
> > request and ack will be controlled by SCU(System Control Unit)
> > firmware(manage clock,power,stop mode, etc. by Cortex-M4 core) in
> > coming i.MX8(QM/QXP). And SCU firmware interface can't be available in
> interrupt context.
> >
> > For compatibillity, the wake up mechanism can't be symmetric, so we
> > need in_stop_mode hack.
> >
> > Fixes: de3578c198c6 ("can: flexcan: add self wakeup support")
> > Reported-by: Sean Nyekjaer <sean@geanix.com>
> > Signed-off-by: Joakim Zhang <qiangqing.zhang@nxp.com>
> >
> 
> Unfortunatly it's still possible to reproduce the deadlock with this patch...
> 
> [  689.921717] flexcan: probe of 2094000.flexcan failed with error -110
> 
> My test setup:
> PC with CAN-USB dongle connected to can0 and can1.
> 
> PC:
> $ while true; do cansend can0 '123#DEADBEEF'; done
> 
> iMX6ull:
> root@iwg26:~# systemctl suspend
> 
> 
> [  365.858054] systemd[1]: Reached target Sleep.
> root@iwg26:~# [  365.939826] systemd[1]: Starting Suspend...
> [  366.115839] systemd-sleep[248]: Suspending system...
> [  366.517949] dpm_run_callback(): platform_pm_suspend+0x0/0x5c returns
> -110 [  366.518249] PM: Device 2094000.flexcan failed to suspend: error -110
> [  366.518406] PM: Some devices failed to suspend, or early wake event
> detected [  366.732162] dpm_run_callback():
> platform_pm_suspend+0x0/0x5c returns -110 [  366.732285] PM: Device
> 2090000.flexcan failed to suspend: error -110 [  366.732330] PM: Some
> devices failed to suspend, or early wake event detected [  366.890637]
> systemd-sleep[248]: System resumed.

CAN1, CAN0 suspended failed, then CAN0, CAN1 resumed back, so CAN0/CAN1 can work fine.

> [  366.923062] systemd[1]: Started Suspend.
> [  366.942819] systemd[1]: sleep.target: Unit not needed anymore. Stopping.
> [  366.954791] systemd[1]: Stopped target Sleep.
> [  366.962402] systemd[1]: Reached target Suspend.
> [  366.977546] systemd-logind[135]: Operation 'sleep' finished.
> [  366.979194] systemd[1]: suspend.target: Unit not needed anymore.
> Stopping.
> [  366.993831] systemd[1]: Stopped target Suspend.
> [  367.139972] systemd-networkd[220]: usb0: Lost carrier [  367.294077]
> systemd-networkd[220]: usb0: Gained carrier
> 
> root@iwg26:~# candump can0 | head -n 2
> 
>    can0  123   [4]  DE AD BE EF
>    can0  123   [4]  DE AD BE EF
> root@iwg26:~# candump can1 | head -n 2
> 
>    can1  123   [4]  DE AD BE EF
>    can1  123   [4]  DE AD BE EF
> root@iwg26:~# systemctl suspend
> 
> root@iwg26:~# [  385.106658] systemd[1]: Reached target Sleep.
> [  385.147602] systemd[1]: Starting Suspend...
> [  385.246421] systemd-sleep[260]: Suspending system...
> [  385.634733] dpm_run_callback(): platform_pm_suspend+0x0/0x5c returns
> -110 [  385.634855] PM: Device 2090000.flexcan failed to suspend: error -110
> [  385.634897] PM: Some devices failed to suspend, or early wake event
> detected [  385.856251] PM: noirq suspend of devices failed [  385.998364]
> systemd-sleep[260]: System resumed.

CAN0 suspended failed, CAN1 noirq suspended failed, then CAN1, CAN0 resumed back, so CAN0/CAN1 can work fine.

> [  386.023390] systemd[1]: Started Suspend.
> [  386.031570] systemd[1]: sleep.target: Unit not needed anymore. Stopping.
> [  386.055886] systemd[1]: Stopped target Sleep.
> [  386.061430] systemd[1]: Reached target Suspend.
> [  386.066142] systemd[1]: suspend.target: Unit not needed anymore.
> Stopping.
> [  386.112575] systemd-networkd[220]: usb0: Lost carrier [  386.116797]
> systemd-logind[135]: Operation 'sleep' finished.
> [  386.146161] systemd[1]: Stopped target Suspend.
> [  386.260866] systemd-networkd[220]: usb0: Gained carrier root@iwg26:~#
> candump can0 | head -n 2
>    can0  123   [4]  DE AD BE EF
>    can0  123   [4]  DE AD BE EF
> root@iwg26:~# candump can1 | head -n 2
> 
>    can1  123   [4]  DE AD BE EF
>    can1  123   [4]  DE AD BE EF
> root@iwg26:~# systemctl suspend
> 
> [  396.919303] systemd[1]: Reached target Sleep.
> root@iwg26:~# [  396.964722] systemd[1]: Starting Suspend...
> [  397.067336] systemd-sleep[268]: Suspending system...
> [  397.574571] PM: noirq suspend of devices failed [  397.834731] PM: noirq
> suspend of devices failed [  397.807996] systemd-networkd[220]: usb0: Lost
> carrier [  398.156295] dpm_run_callback(): platform_pm_suspend+0x0/0x5c
> returns -110 [  398.156339] PM: Device 2094000.flexcan failed to suspend:
> error -110 [  398.156509] PM: Some devices failed to suspend, or early wake
> event detected [  398.053555] systemd-sleep[268]: Failed to write
> /sys/power/state:
> Device or resource busy

But the log here is very strange and chaotic, it looks like CAN0 suspended failed, then resumed back, so CAN0 can work fine.
CAN1 noirq suspend failed, but have not resumed back, so CAN1 still in stop mode, cannot work. I think this may be other device noirq suspend failed
broke the resume of CAN1.

Could you do more debug to help locate the issue?

> [  398.074751] systemd[1]: systemd-suspend.service: Main process exited,
> code=exited, status=1/FAILURE [  398.076779] systemd[1]:

> systemd-suspend.service: Failed with result 'exit-code'.
> [  398.109255] systemd[1]: Failed to start Suspend.
> [  398.118704] systemd[1]: Dependency failed for Suspend.
> [  398.136283] systemd-logind[135]: Operation 'sleep' finished.
> [  398.137770] systemd[1]: suspend.target: Job suspend.target/start failed
> with result 'dependency'.
> [  398.139105] systemd[1]: sleep.target: Unit not needed anymore. Stopping.
> [  398.167590] systemd[1]: Stopped target Sleep.
> [  398.201558] systemd-networkd[220]: usb0: Gained carrier

Log here also strange.

Best Regards,
Joakim Zhang
> root@iwg26:~# candump can0 | head -n 2
>    can0  123   [4]  DE AD BE EF
>    can0  123   [4]  DE AD BE EF
> root@iwg26:~# candump can1 | head -n 2
> 
> nothing on can1 anymore :-(
> 
> root@iwg26:~# rmmod flexcan
> [  622.884746] systemd-networkd[220]: can1: Lost carrier [  623.046766]
> systemd-networkd[220]: can0: Lost carrier root@iwg26:~# insmod
> /mnt/flexcan.ko [  628.323981] flexcan 2094000.flexcan: registering netdev
> failed
> 
> and can1 fails to register with:
> [  628.347485] flexcan: probe of 2094000.flexcan failed with error -110
> 
> /Sean

Re: [PATCH REPOST 1/2] can: flexcan: fix deadlock when using self wakeup

[Sean Nyekjaer]

>> Unfortunatly it's still possible to reproduce the deadlock with this patch...
>>
>> [  689.921717] flexcan: probe of 2094000.flexcan failed with error -110
>>
>> My test setup:
>> PC with CAN-USB dongle connected to can0 and can1.
>>
>> PC:
>> $ while true; do cansend can0 '123#DEADBEEF'; done
>>
>> iMX6ull:
>> root@iwg26:~# systemctl suspend
>>
>>
>> [  365.858054] systemd[1]: Reached target Sleep.
>> root@iwg26:~# [  365.939826] systemd[1]: Starting Suspend...
>> [  366.115839] systemd-sleep[248]: Suspending system...
>> [  366.517949] dpm_run_callback(): platform_pm_suspend+0x0/0x5c returns
>> -110 [  366.518249] PM: Device 2094000.flexcan failed to suspend: error -110
>> [  366.518406] PM: Some devices failed to suspend, or early wake event
>> detected [  366.732162] dpm_run_callback():
>> platform_pm_suspend+0x0/0x5c returns -110 [  366.732285] PM: Device
>> 2090000.flexcan failed to suspend: error -110 [  366.732330] PM: Some
>> devices failed to suspend, or early wake event detected [  366.890637]
>> systemd-sleep[248]: System resumed.
> 
> CAN1, CAN0 suspended failed, then CAN0, CAN1 resumed back, so CAN0/CAN1 can work fine.
> 
>> [  366.923062] systemd[1]: Started Suspend.
>> [  366.942819] systemd[1]: sleep.target: Unit not needed anymore. Stopping.
>> [  366.954791] systemd[1]: Stopped target Sleep.
>> [  366.962402] systemd[1]: Reached target Suspend.
>> [  366.977546] systemd-logind[135]: Operation 'sleep' finished.
>> [  366.979194] systemd[1]: suspend.target: Unit not needed anymore.
>> Stopping.
>> [  366.993831] systemd[1]: Stopped target Suspend.
>> [  367.139972] systemd-networkd[220]: usb0: Lost carrier [  367.294077]
>> systemd-networkd[220]: usb0: Gained carrier
>>
>> root@iwg26:~# candump can0 | head -n 2
>>
>>     can0  123   [4]  DE AD BE EF
>>     can0  123   [4]  DE AD BE EF
>> root@iwg26:~# candump can1 | head -n 2
>>
>>     can1  123   [4]  DE AD BE EF
>>     can1  123   [4]  DE AD BE EF
>> root@iwg26:~# systemctl suspend
>>
>> root@iwg26:~# [  385.106658] systemd[1]: Reached target Sleep.
>> [  385.147602] systemd[1]: Starting Suspend...
>> [  385.246421] systemd-sleep[260]: Suspending system...
>> [  385.634733] dpm_run_callback(): platform_pm_suspend+0x0/0x5c returns
>> -110 [  385.634855] PM: Device 2090000.flexcan failed to suspend: error -110
>> [  385.634897] PM: Some devices failed to suspend, or early wake event
>> detected [  385.856251] PM: noirq suspend of devices failed [  385.998364]
>> systemd-sleep[260]: System resumed.
> 
> CAN0 suspended failed, CAN1 noirq suspended failed, then CAN1, CAN0 resumed back, so CAN0/CAN1 can work fine.
> 
>> [  386.023390] systemd[1]: Started Suspend.
>> [  386.031570] systemd[1]: sleep.target: Unit not needed anymore. Stopping.
>> [  386.055886] systemd[1]: Stopped target Sleep.
>> [  386.061430] systemd[1]: Reached target Suspend.
>> [  386.066142] systemd[1]: suspend.target: Unit not needed anymore.
>> Stopping.
>> [  386.112575] systemd-networkd[220]: usb0: Lost carrier [  386.116797]
>> systemd-logind[135]: Operation 'sleep' finished.
>> [  386.146161] systemd[1]: Stopped target Suspend.
>> [  386.260866] systemd-networkd[220]: usb0: Gained carrier root@iwg26:~#
>> candump can0 | head -n 2
>>     can0  123   [4]  DE AD BE EF
>>     can0  123   [4]  DE AD BE EF
>> root@iwg26:~# candump can1 | head -n 2
>>
>>     can1  123   [4]  DE AD BE EF
>>     can1  123   [4]  DE AD BE EF
>> root@iwg26:~# systemctl suspend
>>
>> [  396.919303] systemd[1]: Reached target Sleep.
>> root@iwg26:~# [  396.964722] systemd[1]: Starting Suspend...
>> [  397.067336] systemd-sleep[268]: Suspending system...
>> [  397.574571] PM: noirq suspend of devices failed [  397.834731] PM: noirq
>> suspend of devices failed [  397.807996] systemd-networkd[220]: usb0: Lost
>> carrier [  398.156295] dpm_run_callback(): platform_pm_suspend+0x0/0x5c
>> returns -110 [  398.156339] PM: Device 2094000.flexcan failed to suspend:
>> error -110 [  398.156509] PM: Some devices failed to suspend, or early wake
>> event detected [  398.053555] systemd-sleep[268]: Failed to write
>> /sys/power/state:
>> Device or resource busy
> 
> But the log here is very strange and chaotic, it looks like CAN0 suspended failed, then resumed back, so CAN0 can work fine.
> CAN1 noirq suspend failed, but have not resumed back, so CAN1 still in stop mode, cannot work. I think this may be other device noirq suspend failed
> broke the resume of CAN1.
> 
> Could you do more debug to help locate the issue?
> 
>> [  398.074751] systemd[1]: systemd-suspend.service: Main process exited,
>> code=exited, status=1/FAILURE [  398.076779] systemd[1]:
> 
>> systemd-suspend.service: Failed with result 'exit-code'.
>> [  398.109255] systemd[1]: Failed to start Suspend.
>> [  398.118704] systemd[1]: Dependency failed for Suspend.
>> [  398.136283] systemd-logind[135]: Operation 'sleep' finished.
>> [  398.137770] systemd[1]: suspend.target: Job suspend.target/start failed
>> with result 'dependency'.
>> [  398.139105] systemd[1]: sleep.target: Unit not needed anymore. Stopping.
>> [  398.167590] systemd[1]: Stopped target Sleep.
>> [  398.201558] systemd-networkd[220]: usb0: Gained carrier
> 
> Log here also strange.
> 
> Best Regards,
> Joakim Zhang
>> root@iwg26:~# candump can0 | head -n 2
>>     can0  123   [4]  DE AD BE EF
>>     can0  123   [4]  DE AD BE EF
>> root@iwg26:~# candump can1 | head -n 2
>>
>> nothing on can1 anymore :-(
>>
>> root@iwg26:~# rmmod flexcan
>> [  622.884746] systemd-networkd[220]: can1: Lost carrier [  623.046766]
>> systemd-networkd[220]: can0: Lost carrier root@iwg26:~# insmod
>> /mnt/flexcan.ko [  628.323981] flexcan 2094000.flexcan: registering netdev
>> failed
>>
>> and can1 fails to register with:
>> [  628.347485] flexcan: probe of 2094000.flexcan failed with error -110
>>
>> /Sean

I have added some more debug, same test setup:
https://gist.github.com/sknsean/81208714de23aa3639d3e31dccb2f3e0

root@iwg26:~# systemctl suspend 
 

...
https://gist.github.com/sknsean/2a786f1543305056d4de03d387872403

/Sean

Re: [PATCH REPOST 1/2] can: flexcan: fix deadlock when using self wakeup

[Sean Nyekjaer]

On 20/08/2019 13.55, Sean Nyekjaer wrote:
> 
> I have added some more debug, same test setup:
> https://gist.github.com/sknsean/81208714de23aa3639d3e31dccb2f3e0
> 
> root@iwg26:~# systemctl suspend
> 
> ...
> https://gist.github.com/sknsean/2a786f1543305056d4de03d387872403
> 
> /Sean

Any luck reproducing this?

/Sean

RE: [PATCH REPOST 1/2] can: flexcan: fix deadlock when using self wakeup

[Joakim Zhang]

> -----Original Message-----
> From: Sean Nyekjaer <sean@geanix.com>
> Sent: 2019年8月28日 21:25
> To: Joakim Zhang <qiangqing.zhang@nxp.com>; mkl@pengutronix.de;
> linux-can@vger.kernel.org
> Cc: wg@grandegger.com; netdev@vger.kernel.org; dl-linux-imx
> <linux-imx@nxp.com>; Martin Hundebøll <martin@geanix.com>
> Subject: Re: [PATCH REPOST 1/2] can: flexcan: fix deadlock when using self
> wakeup
> 
> 
> 
> On 20/08/2019 13.55, Sean Nyekjaer wrote:
> >
> > I have added some more debug, same test setup:
> >
> https://eur01.safelinks.protection.outlook.com/?url=https%3A%2F%2Fgist.gith
> ub.com%2Fsknsean%2F81208714de23aa3639d3e31dccb2f3e0&amp;data=02%
> 7C01%7Cqiangqing.zhang%40nxp.com%7C1dae7ec4f191462be43d08d72bbb1
> e82%7C686ea1d3bc2b4c6fa92cd99c5c301635%7C0%7C0%7C63702595498952
> 9813&amp;sdata=u2t747L4mi87ejuaLwl4WWJNJIFIzvlEfNE%2BSLq2Kbc%3D&
> amp;reserved=0
> >
> > root@iwg26:~# systemctl suspend
> >
> > ...
> >
> https://eur01.safelinks.protection.outlook.com/?url=https%3A%2F%2Fgist.gith
> ub.com%2Fsknsean%2F2a786f1543305056d4de03d387872403&amp;data=02
> %7C01%7Cqiangqing.zhang%40nxp.com%7C1dae7ec4f191462be43d08d72bbb
> 1e82%7C686ea1d3bc2b4c6fa92cd99c5c301635%7C0%7C0%7C6370259549895
> 29813&amp;sdata=WbI2eeIlrNC6HUSviagaiAyi4YpK%2B2bC3al4Yn9EXZM%3D
> &amp;reserved=0
> >
> > /Sean
> 
> Any luck reproducing this?

Hi Sean,

I'm sorry that I can't get the debug log as the site can't be reached. And I connect two boards to do test at my side, this issue can't be reproduced.

Best Regards,
Joakim Zhang
> /Sean

Re: [PATCH REPOST 1/2] can: flexcan: fix deadlock when using self wakeup

[Sean Nyekjaer]

On 29/08/2019 09.30, Joakim Zhang wrote:
> Hi Sean,
> 
> I'm sorry that I can't get the debug log as the site can't be reached. And I connect two boards to do test at my side, this issue can't be reproduced.
> 
> Best Regards,
> Joakim Zhang

Hi Joakim,

What commit and branch are you doing your tests with?

/Sean

RE: [PATCH REPOST 1/2] can: flexcan: fix deadlock when using self wakeup

[Joakim Zhang]

> -----Original Message-----
> From: Sean Nyekjaer <sean@geanix.com>
> Sent: 2019年9月5日 13:58
> To: Joakim Zhang <qiangqing.zhang@nxp.com>; mkl@pengutronix.de;
> linux-can@vger.kernel.org
> Cc: wg@grandegger.com; netdev@vger.kernel.org; dl-linux-imx
> <linux-imx@nxp.com>; Martin Hundebøll <martin@geanix.com>
> Subject: Re: [PATCH REPOST 1/2] can: flexcan: fix deadlock when using self
> wakeup
> 
> 
> 
> On 29/08/2019 09.30, Joakim Zhang wrote:
> > Hi Sean,
> >
> > I'm sorry that I can't get the debug log as the site can't be reached. And I
> connect two boards to do test at my side, this issue can't be reproduced.
> >
> > Best Regards,
> > Joakim Zhang
> 
> Hi Joakim,
> 
> What commit and branch are you doing your tests with?

Hi Sean,

Could you update lastest flexcan driver using linux-can-next/flexcan and then merge below two patches from linux-can/testing?
d0b53616716e (HEAD -> testing, origin/testing) can: flexcan: add LPSR mode support for i.MX7D
803eb6bad65b can: flexcan: fix deadlock when using self wakeup

Best Regards,
Joakim Zhang
> /Sean

Re: [PATCH REPOST 1/2] can: flexcan: fix deadlock when using self wakeup

[Sean Nyekjaer]

On 05/09/2019 09.10, Joakim Zhang wrote:
> Hi Sean,
> 
> Could you update lastest flexcan driver using linux-can-next/flexcan and then merge below two patches from linux-can/testing?
> d0b53616716e (HEAD -> testing, origin/testing) can: flexcan: add LPSR mode support for i.MX7D
> 803eb6bad65b can: flexcan: fix deadlock when using self wakeup
> 
> Best Regards,
> Joakim Zhang

The testing branch have some UBI bugs, when suspending it crashes...
So will have to leave this, until they are resolved :-)

/Sean

Re: [PATCH REPOST 1/2] can: flexcan: fix deadlock when using self wakeup

[Marc Kleine-Budde]

[-- Attachment #1.1: Type: text/plain, Size: 947 bytes --]

On 9/5/19 3:17 PM, Sean Nyekjaer wrote:
> 
> 
> On 05/09/2019 09.10, Joakim Zhang wrote:
>> Hi Sean,
>>
>> Could you update lastest flexcan driver using linux-can-next/flexcan and then merge below two patches from linux-can/testing?
>> d0b53616716e (HEAD -> testing, origin/testing) can: flexcan: add LPSR mode support for i.MX7D
>> 803eb6bad65b can: flexcan: fix deadlock when using self wakeup
>>
>> Best Regards,
>> Joakim Zhang
> 
> The testing branch have some UBI bugs, when suspending it crashes...
> So will have to leave this, until they are resolved :-)

For what it's worth, I've rebased the testing branch to the latest
net/master.

Marc

-- 
Pengutronix e.K.                  | Marc Kleine-Budde           |
Industrial Linux Solutions        | Phone: +49-231-2826-924     |
Vertretung West/Dortmund          | Fax:   +49-5121-206917-5555 |
Amtsgericht Hildesheim, HRA 2686  | http://www.pengutronix.de   |


[-- Attachment #2: OpenPGP digital signature --]
[-- Type: application/pgp-signature, Size: 488 bytes --]

RE: [PATCH REPOST 1/2] can: flexcan: fix deadlock when using self wakeup

[Joakim Zhang]

> -----Original Message-----
> From: Sean Nyekjaer <sean@geanix.com>
> Sent: 2019年9月5日 21:18
> To: Joakim Zhang <qiangqing.zhang@nxp.com>; mkl@pengutronix.de;
> linux-can@vger.kernel.org
> Cc: wg@grandegger.com; netdev@vger.kernel.org; dl-linux-imx
> <linux-imx@nxp.com>; Martin Hundebøll <martin@geanix.com>
> Subject: Re: [PATCH REPOST 1/2] can: flexcan: fix deadlock when using self
> wakeup
> 
> 
> 
> On 05/09/2019 09.10, Joakim Zhang wrote:
> > Hi Sean,
> >
> > Could you update lastest flexcan driver using linux-can-next/flexcan and then
> merge below two patches from linux-can/testing?
> > d0b53616716e (HEAD -> testing, origin/testing) can: flexcan: add LPSR
> > mode support for i.MX7D 803eb6bad65b can: flexcan: fix deadlock when
> > using self wakeup
> >
> > Best Regards,
> > Joakim Zhang
> 
> The testing branch have some UBI bugs, when suspending it crashes...
> So will have to leave this, until they are resolved :-)

I think you can find the base and cherry-pick all above flexcan related latest patches to your local stable tree.
I did this and test wakeup function on i.MX8QM/QXP before.

BTW, I think without CAN FD related patches, you still can test wakeup function on i.MX6/7 with this patch(may need fix merge conflicts)
This patch has been merged into our 4.19 kernel and passed the wakeup test for i.MX6/7/8. I went through the flexcan suspend/resume process again,
and not find logical issue. If you met wakeup failure, could you help to locate the problem more accurate. Failure log you provided last time, strange
and illogical.

Thanks a lot! 😊
 	
Best Regards,
Joakim Zhang
> /Sean

Re: [PATCH REPOST 1/2] can: flexcan: fix deadlock when using self wakeup

[Sean Nyekjaer]

On 05/09/2019 09.10, Joakim Zhang wrote:
> Hi Sean,
> 
> Could you update lastest flexcan driver using linux-can-next/flexcan and then merge below two patches from linux-can/testing?
> d0b53616716e (HEAD -> testing, origin/testing) can: flexcan: add LPSR mode support for i.MX7D
> 803eb6bad65b can: flexcan: fix deadlock when using self wakeup
> 
> Best Regards,
> Joakim Zhang

Hi

I reverted 2 commits on thw nand driver and got the testing kernel to work.

I can confirm the issue is resolved with this patch :-)

/Sean

RE: [PATCH REPOST 1/2] can: flexcan: fix deadlock when using self wakeup

[Joakim Zhang]

> -----Original Message-----
> From: Sean Nyekjaer <sean@geanix.com>
> Sent: 2019年9月10日 15:53
> To: Joakim Zhang <qiangqing.zhang@nxp.com>; mkl@pengutronix.de;
> linux-can@vger.kernel.org
> Cc: wg@grandegger.com; netdev@vger.kernel.org; dl-linux-imx
> <linux-imx@nxp.com>; Martin Hundebøll <martin@geanix.com>
> Subject: Re: [PATCH REPOST 1/2] can: flexcan: fix deadlock when using self
> wakeup
> 
> 
> 
> On 05/09/2019 09.10, Joakim Zhang wrote:
> > Hi Sean,
> >
> > Could you update lastest flexcan driver using linux-can-next/flexcan and then
> merge below two patches from linux-can/testing?
> > d0b53616716e (HEAD -> testing, origin/testing) can: flexcan: add LPSR
> > mode support for i.MX7D 803eb6bad65b can: flexcan: fix deadlock when
> > using self wakeup
> >
> > Best Regards,
> > Joakim Zhang
> 
> Hi
> 
> I reverted 2 commits on thw nand driver and got the testing kernel to work.
> 
> I can confirm the issue is resolved with this patch :-)

Hi Marc,

How about these two fixes for Flexcan?

Best Regards,
Joakim Zhang
> /Sean

RE: [PATCH REPOST 1/2] can: flexcan: fix deadlock when using self wakeup

[Joakim Zhang]

> -----Original Message-----
> From: Joakim Zhang
> Sent: 2019年8月20日 19:25
> To: Sean Nyekjaer <sean@geanix.com>; mkl@pengutronix.de;
> linux-can@vger.kernel.org
> Cc: wg@grandegger.com; netdev@vger.kernel.org; dl-linux-imx
> <linux-imx@nxp.com>; Martin Hundebøll <martin@geanix.com>
> Subject: RE: [PATCH REPOST 1/2] can: flexcan: fix deadlock when using self
> wakeup
> 
> 
> > -----Original Message-----
> > From: Sean Nyekjaer <sean@geanix.com>
> > Sent: 2019年8月20日 18:25
> > To: Joakim Zhang <qiangqing.zhang@nxp.com>; mkl@pengutronix.de;
> > linux-can@vger.kernel.org
> > Cc: wg@grandegger.com; netdev@vger.kernel.org; dl-linux-imx
> > <linux-imx@nxp.com>; Martin Hundebøll <martin@geanix.com>
> > Subject: Re: [PATCH REPOST 1/2] can: flexcan: fix deadlock when using
> > self wakeup
> >
> >
> >
> > On 16/08/2019 10.20, Joakim Zhang wrote:
> > > As reproted by Sean Nyekjaer below:
> > > 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.
> > >
> > > The best way to exit stop mode is in Wake Up interrupt context, and
> > > then
> > > suspend() and resume() functions can be symmetric. However, stop
> > > mode request and ack will be controlled by SCU(System Control Unit)
> > > firmware(manage clock,power,stop mode, etc. by Cortex-M4 core) in
> > > coming i.MX8(QM/QXP). And SCU firmware interface can't be available
> > > in
> > interrupt context.
> > >
> > > For compatibillity, the wake up mechanism can't be symmetric, so we
> > > need in_stop_mode hack.
> > >
> > > Fixes: de3578c198c6 ("can: flexcan: add self wakeup support")
> > > Reported-by: Sean Nyekjaer <sean@geanix.com>
> > > Signed-off-by: Joakim Zhang <qiangqing.zhang@nxp.com>
> > >
> >
> > Unfortunatly it's still possible to reproduce the deadlock with this patch...
> >
> > [  689.921717] flexcan: probe of 2094000.flexcan failed with error
> > -110
> >
> > My test setup:
> > PC with CAN-USB dongle connected to can0 and can1.
> >
> > PC:
> > $ while true; do cansend can0 '123#DEADBEEF'; done
> >
> > iMX6ull:
> > root@iwg26:~# systemctl suspend
> >
> >
> > [  365.858054] systemd[1]: Reached target Sleep.
> > root@iwg26:~# [  365.939826] systemd[1]: Starting Suspend...
> > [  366.115839] systemd-sleep[248]: Suspending system...
> > [  366.517949] dpm_run_callback(): platform_pm_suspend+0x0/0x5c
> > returns
> > -110 [  366.518249] PM: Device 2094000.flexcan failed to suspend:
> > error -110 [  366.518406] PM: Some devices failed to suspend, or early
> > wake event detected [  366.732162] dpm_run_callback():
> > platform_pm_suspend+0x0/0x5c returns -110 [  366.732285] PM: Device
> > 2090000.flexcan failed to suspend: error -110 [  366.732330] PM: Some
> > devices failed to suspend, or early wake event detected [  366.890637]
> > systemd-sleep[248]: System resumed.
> 
> CAN1, CAN0 suspended failed, then CAN0, CAN1 resumed back, so
> CAN0/CAN1 can work fine.
>
> > [  366.923062] systemd[1]: Started Suspend.
> > [  366.942819] systemd[1]: sleep.target: Unit not needed anymore.
> Stopping.
> > [  366.954791] systemd[1]: Stopped target Sleep.
> > [  366.962402] systemd[1]: Reached target Suspend.
> > [  366.977546] systemd-logind[135]: Operation 'sleep' finished.
> > [  366.979194] systemd[1]: suspend.target: Unit not needed anymore.
> > Stopping.
> > [  366.993831] systemd[1]: Stopped target Suspend.
> > [  367.139972] systemd-networkd[220]: usb0: Lost carrier [
> > 367.294077]
> > systemd-networkd[220]: usb0: Gained carrier
> >
> > root@iwg26:~# candump can0 | head -n 2
> >
> >    can0  123   [4]  DE AD BE EF
> >    can0  123   [4]  DE AD BE EF
> > root@iwg26:~# candump can1 | head -n 2
> >
> >    can1  123   [4]  DE AD BE EF
> >    can1  123   [4]  DE AD BE EF
> > root@iwg26:~# systemctl suspend
> >
> > root@iwg26:~# [  385.106658] systemd[1]: Reached target Sleep.
> > [  385.147602] systemd[1]: Starting Suspend...
> > [  385.246421] systemd-sleep[260]: Suspending system...
> > [  385.634733] dpm_run_callback(): platform_pm_suspend+0x0/0x5c
> > returns
> > -110 [  385.634855] PM: Device 2090000.flexcan failed to suspend:
> > error -110 [  385.634897] PM: Some devices failed to suspend, or early
> > wake event detected [  385.856251] PM: noirq suspend of devices failed
> > [  385.998364]
> > systemd-sleep[260]: System resumed.
> 
> CAN0 suspended failed, CAN1 noirq suspended failed, then CAN1, CAN0
> resumed back, so CAN0/CAN1 can work fine.

If CAN0 suspended failed, should system resumed after suspended all devices, should not enter noirq suspend, 
why it here printed "PM: noirq suspend of devices failed"?

> > [  386.023390] systemd[1]: Started Suspend.
> > [  386.031570] systemd[1]: sleep.target: Unit not needed anymore.
> Stopping.
> > [  386.055886] systemd[1]: Stopped target Sleep.
> > [  386.061430] systemd[1]: Reached target Suspend.
> > [  386.066142] systemd[1]: suspend.target: Unit not needed anymore.
> > Stopping.
> > [  386.112575] systemd-networkd[220]: usb0: Lost carrier [
> > 386.116797]
> > systemd-logind[135]: Operation 'sleep' finished.
> > [  386.146161] systemd[1]: Stopped target Suspend.
> > [  386.260866] systemd-networkd[220]: usb0: Gained carrier
> > root@iwg26:~# candump can0 | head -n 2
> >    can0  123   [4]  DE AD BE EF
> >    can0  123   [4]  DE AD BE EF
> > root@iwg26:~# candump can1 | head -n 2
> >
> >    can1  123   [4]  DE AD BE EF
> >    can1  123   [4]  DE AD BE EF
> > root@iwg26:~# systemctl suspend
> >
> > [  396.919303] systemd[1]: Reached target Sleep.
> > root@iwg26:~# [  396.964722] systemd[1]: Starting Suspend...
> > [  397.067336] systemd-sleep[268]: Suspending system...
> > [  397.574571] PM: noirq suspend of devices failed [  397.834731] PM:
> > noirq suspend of devices failed [  397.807996] systemd-networkd[220]:
> > usb0: Lost carrier [  398.156295] dpm_run_callback():
> > platform_pm_suspend+0x0/0x5c returns -110 [  398.156339] PM: Device
> 2094000.flexcan failed to suspend:
> > error -110 [  398.156509] PM: Some devices failed to suspend, or early
> > wake event detected [  398.053555] systemd-sleep[268]: Failed to write
> > /sys/power/state:
> > Device or resource busy
> 
> But the log here is very strange and chaotic, it looks like CAN0 suspended failed,
> then resumed back, so CAN0 can work fine.
> CAN1 noirq suspend failed, but have not resumed back, so CAN1 still in stop
> mode, cannot work. I think this may be other device noirq suspend failed broke
> the resume of CAN1.
> 
> Could you do more debug to help locate the issue?

More strange, why here first enter noirq suspend?

Best Regards,
Joakim Zhang
> > [  398.074751] systemd[1]: systemd-suspend.service: Main process
> > exited, code=exited, status=1/FAILURE [  398.076779] systemd[1]:
> 
> > systemd-suspend.service: Failed with result 'exit-code'.
> > [  398.109255] systemd[1]: Failed to start Suspend.
> > [  398.118704] systemd[1]: Dependency failed for Suspend.
> > [  398.136283] systemd-logind[135]: Operation 'sleep' finished.
> > [  398.137770] systemd[1]: suspend.target: Job suspend.target/start
> > failed with result 'dependency'.
> > [  398.139105] systemd[1]: sleep.target: Unit not needed anymore.
> Stopping.
> > [  398.167590] systemd[1]: Stopped target Sleep.
> > [  398.201558] systemd-networkd[220]: usb0: Gained carrier
> 
> Log here also strange.
> 
> Best Regards,
> Joakim Zhang
> > root@iwg26:~# candump can0 | head -n 2
> >    can0  123   [4]  DE AD BE EF
> >    can0  123   [4]  DE AD BE EF
> > root@iwg26:~# candump can1 | head -n 2
> >
> > nothing on can1 anymore :-(
> >
> > root@iwg26:~# rmmod flexcan
> > [  622.884746] systemd-networkd[220]: can1: Lost carrier [
> > 623.046766]
> > systemd-networkd[220]: can0: Lost carrier root@iwg26:~# insmod
> > /mnt/flexcan.ko [  628.323981] flexcan 2094000.flexcan: registering
> > netdev failed
> >
> > and can1 fails to register with:
> > [  628.347485] flexcan: probe of 2094000.flexcan failed with error
> > -110
> >
> > /Sean

[PATCH REPOST 2/2] can: flexcan: add LPSR mode support for i.MX7D

[Joakim Zhang]

For i.MX7D LPSR mode, the controller will lost power and got the
configuration state lost after system resume back. (coming i.MX8QM/QXP
will also completely power off the domain, the controller state will be
lost and needs restore).
So we need to set pinctrl state again and re-start chip to do
re-configuration after resume.

For wakeup case, it should not set pinctrl to sleep state by
pinctrl_pm_select_sleep_state.
For interface is not up before suspend case, we don't need
re-configure as it will be configured by user later by interface up.

Signed-off-by: Joakim Zhang <qiangqing.zhang@nxp.com>

ChangeLog:
V1->V2:
	* rebase on linux-can/testing.
	* move into a patch set.
---
 drivers/net/can/flexcan.c | 11 +++++++----
 1 file changed, 7 insertions(+), 4 deletions(-)

diff --git a/drivers/net/can/flexcan.c b/drivers/net/can/flexcan.c
index de2bf71b335b..b3edaf6a5a61 100644
--- a/drivers/net/can/flexcan.c
+++ b/drivers/net/can/flexcan.c
@@ -25,6 +25,7 @@
 #include <linux/of_device.h>
 #include <linux/platform_device.h>
 #include <linux/regulator/consumer.h>
+#include <linux/pinctrl/consumer.h>
 #include <linux/regmap.h>
 
 #define DRV_NAME			"flexcan"
@@ -1640,9 +1641,9 @@ static int __maybe_unused flexcan_suspend(struct device *device)
 
 			priv->in_stop_mode = true;
 		} else {
-			err = flexcan_chip_disable(priv);
-			if (err)
-				return err;
+			flexcan_chip_stop(dev);
+
+			pinctrl_pm_select_sleep_state(device);
 		}
 		netif_stop_queue(dev);
 		netif_device_detach(dev);
@@ -1674,7 +1675,9 @@ static int __maybe_unused flexcan_resume(struct device *device)
 
 			disable_irq_wake(dev->irq);
 		} else {
-			err = flexcan_chip_enable(priv);
+			pinctrl_pm_select_default_state(device);
+
+			err = flexcan_chip_start(dev);
 			if (err)
 				return err;
 		}
-- 
2.17.1