This is a note to let you know that I've just added the patch titled
can: flexcan: flexcan_chip_start(): fix erroneous flexcan_transceiver_enable() during bus-off recovery
to the 5.9-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
can-flexcan-flexcan_chip_start-fix-erroneous-flexcan.patch
and it can be found in the queue-5.9 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
commit a96c73679da53d5207961e3020827d8903f96b64
Author: Marc Kleine-Budde <mkl@xxxxxxxxxxxxxx>
Date: Wed Nov 18 16:01:48 2020 +0100
can: flexcan: flexcan_chip_start(): fix erroneous flexcan_transceiver_enable() during bus-off recovery
[ Upstream commit cd9f13c59461351d7a5fd07924264fb49b287359 ]
If the CAN controller goes into bus off, the do_set_mode() callback with
CAN_MODE_START can be used to recover the controller, which then calls
flexcan_chip_start(). If configured, this is done automatically by the
framework or manually by the user.
In flexcan_chip_start() there is an explicit call to
flexcan_transceiver_enable(), which does a regulator_enable() on the
transceiver regulator. This results in a net usage counter increase, as there
is no corresponding flexcan_transceiver_disable() in the bus off code path.
This further leads to the transceiver stuck enabled, even if the CAN interface
is shut down.
To fix this problem the
flexcan_transceiver_enable()/flexcan_transceiver_disable() are moved out of
flexcan_chip_start()/flexcan_chip_stop() into flexcan_open()/flexcan_close().
Fixes: e955cead0311 ("CAN: Add Flexcan CAN controller driver")
Link: https://lore.kernel.org/r/20201118150148.2664024-1-mkl@xxxxxxxxxxxxxx
Signed-off-by: Marc Kleine-Budde <mkl@xxxxxxxxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
diff --git a/drivers/net/can/flexcan.c b/drivers/net/can/flexcan.c
index 20a56f389c20c..4cbe8889f546f 100644
--- a/drivers/net/can/flexcan.c
+++ b/drivers/net/can/flexcan.c
@@ -1229,14 +1229,10 @@ static int flexcan_chip_start(struct net_device *dev)
priv->write(reg_mecr, ®s->mecr);
}
- err = flexcan_transceiver_enable(priv);
- if (err)
- goto out_chip_disable;
-
/* synchronize with the can bus */
err = flexcan_chip_unfreeze(priv);
if (err)
- goto out_transceiver_disable;
+ goto out_chip_disable;
priv->can.state = CAN_STATE_ERROR_ACTIVE;
@@ -1254,8 +1250,6 @@ static int flexcan_chip_start(struct net_device *dev)
return 0;
- out_transceiver_disable:
- flexcan_transceiver_disable(priv);
out_chip_disable:
flexcan_chip_disable(priv);
return err;
@@ -1285,7 +1279,6 @@ static int __flexcan_chip_stop(struct net_device *dev, bool disable_on_error)
priv->write(priv->reg_ctrl_default & ~FLEXCAN_CTRL_ERR_ALL,
®s->ctrl);
- flexcan_transceiver_disable(priv);
priv->can.state = CAN_STATE_STOPPED;
return 0;
@@ -1321,10 +1314,14 @@ static int flexcan_open(struct net_device *dev)
if (err)
goto out_runtime_put;
- err = request_irq(dev->irq, flexcan_irq, IRQF_SHARED, dev->name, dev);
+ err = flexcan_transceiver_enable(priv);
if (err)
goto out_close;
+ err = request_irq(dev->irq, flexcan_irq, IRQF_SHARED, dev->name, dev);
+ if (err)
+ goto out_transceiver_disable;
+
priv->mb_size = sizeof(struct flexcan_mb) + CAN_MAX_DLEN;
priv->mb_count = (sizeof(priv->regs->mb[0]) / priv->mb_size) +
(sizeof(priv->regs->mb[1]) / priv->mb_size);
@@ -1373,6 +1370,8 @@ static int flexcan_open(struct net_device *dev)
can_rx_offload_del(&priv->offload);
out_free_irq:
free_irq(dev->irq, dev);
+ out_transceiver_disable:
+ flexcan_transceiver_disable(priv);
out_close:
close_candev(dev);
out_runtime_put:
@@ -1391,6 +1390,7 @@ static int flexcan_close(struct net_device *dev)
can_rx_offload_del(&priv->offload);
free_irq(dev->irq, dev);
+ flexcan_transceiver_disable(priv);
close_candev(dev);
pm_runtime_put(priv->dev);
