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can: flexcan: flexcan_chip_start(): fix erroneous flexcan_transceiver_enable() during bus-off recovery 

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: e955cead03 ("CAN: Add Flexcan CAN controller driver")
Link: https://lore.kernel.org/r/20201118150148.2664024-1-mkl@pengutronix.de
Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>
This commit is contained in:
Marc Kleine-Budde 2020-11-18 16:01:48 +01:00
parent d003868d7f
commit cd9f13c594
1 changed files with 9 additions and 9 deletions
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18
drivers/net/can/flexcan.c
View File

@ -1567,14 +1567,10 @@ static int flexcan_chip_start(struct net_device *dev)
priv->write(reg_ctrl2, &regs->ctrl2);
}
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;
@ -1592,8 +1588,6 @@ 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;
@ -1623,7 +1617,6 @@ static int __flexcan_chip_stop(struct net_device *dev, bool disable_on_error)
priv->write(priv->reg_ctrl_default & ~FLEXCAN_CTRL_ERR_ALL,
&regs->ctrl);
flexcan_transceiver_disable(priv);
priv->can.state = CAN_STATE_STOPPED;
return 0;
@ -1665,10 +1658,14 @@ 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;
if (priv->can.ctrlmode & CAN_CTRLMODE_FD)
priv->mb_size = sizeof(struct flexcan_mb) + CANFD_MAX_DLEN;
else
@ -1720,6 +1717,8 @@ 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:
@ -1738,6 +1737,7 @@ 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);