[PATCH v3 1/2] can: flexcan: only change CAN state when link up in system PM

[haibo . chen]

From: Haibo Chen <haibo.chen@xxxxxxx>

After a suspend/resume cycle on a down interface, it will come up as
ERROR-ACTIVE.

$ ip -details -s -s a s dev flexcan0
3: flexcan0: <NOARP,ECHO> mtu 16 qdisc pfifo_fast state DOWN group default qlen 10
    link/can  promiscuity 0 allmulti 0 minmtu 0 maxmtu 0
    can state STOPPED (berr-counter tx 0 rx 0) restart-ms 1000

$ sudo systemctl suspend

$ ip -details -s -s a s dev flexcan0
3: flexcan0: <NOARP,ECHO> mtu 16 qdisc pfifo_fast state DOWN group default qlen 10
    link/can  promiscuity 0 allmulti 0 minmtu 0 maxmtu 0
    can state ERROR-ACTIVE (berr-counter tx 0 rx 0) restart-ms 1000

And only set CAN state to CAN_STATE_ERROR_ACTIVE when resume process
has no issue, otherwise keep in CAN_STATE_SLEEPING as suspend did.

Fixes: 4de349e786a3 ("can: flexcan: fix resume function")
Cc: stable@xxxxxxxxxxxxxxx
Signed-off-by: Haibo Chen <haibo.chen@xxxxxxx>
---
Changes for v3:
 - only handle priv->can.state when netif_running(dev) return true in PM.
---
 drivers/net/can/flexcan/flexcan-core.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/drivers/net/can/flexcan/flexcan-core.c b/drivers/net/can/flexcan/flexcan-core.c
index b347a1c93536..d4d342d8f490 100644
--- a/drivers/net/can/flexcan/flexcan-core.c
+++ b/drivers/net/can/flexcan/flexcan-core.c
@@ -2299,8 +2299,8 @@ static int __maybe_unused flexcan_suspend(struct device *device)
 		}
 		netif_stop_queue(dev);
 		netif_device_detach(dev);
+		priv->can.state = CAN_STATE_SLEEPING;
 	}
-	priv->can.state = CAN_STATE_SLEEPING;
 
 	return 0;
 }
@@ -2311,7 +2311,6 @@ static int __maybe_unused flexcan_resume(struct device *device)
 	struct flexcan_priv *priv = netdev_priv(dev);
 	int err;
 
-	priv->can.state = CAN_STATE_ERROR_ACTIVE;
 	if (netif_running(dev)) {
 		netif_device_attach(dev);
 		netif_start_queue(dev);
@@ -2331,6 +2330,7 @@ static int __maybe_unused flexcan_resume(struct device *device)
 
 			flexcan_chip_interrupts_enable(dev);
 		}
+		priv->can.state = CAN_STATE_ERROR_ACTIVE;
 	}
 
 	return 0;
-- 
2.34.1