Commit cd9f13c5 authored by Marc Kleine-Budde's avatar Marc Kleine-Budde
Browse files

can: flexcan: flexcan_chip_start(): fix erroneous flexcan_transceiver_enable()... 

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: e955cead ("CAN: Add Flexcan CAN controller driver")
Link: https://lore.kernel.org/r/20201118150148.2664024-1-mkl@pengutronix.de


Signed-off-by: default avatarMarc Kleine-Budde <mkl@pengutronix.de>
parent d003868d

drivers/net/can/flexcan.c

+9 −9
Original line number Diff line number Diff line
@@ -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);

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