Commit 3d9db29b authored by Marc Kleine-Budde's avatar Marc Kleine-Budde
Browse files

can: m_can: m_can_handle_state_errors(): fix CAN state transition to Error Active 



The CAN Error State is determined by the receive and transmit error
counters. The CAN error counters decrease when reception/transmission
is successful, so that a status transition back to the Error Active
status is possible. This transition is not handled by
m_can_handle_state_errors().

Add the missing detection of the Error Active state to
m_can_handle_state_errors() and extend the handling of this state in
m_can_handle_state_change().

Fixes: e0d1f481 ("can: m_can: add Bosch M_CAN controller support")
Fixes: cd0d83ea ("can: m_can: m_can_handle_state_change(): fix state change")
Reviewed-by: default avatarMarkus Schneider-Pargmann <msp@baylibre.com>
Link: https://patch.msgid.link/20250929-m_can-fix-state-handling-v4-2-682b49b49d9a@pengutronix.de


Signed-off-by: default avatarMarc Kleine-Budde <mkl@pengutronix.de>
parent ba569fb0

drivers/net/can/m_can/m_can.c

+32 −21
Original line number Diff line number Diff line
@@ -812,6 +812,9 @@ static int m_can_handle_state_change(struct net_device *dev, 
	u32 timestamp = 0;



	switch (new_state) {

	case CAN_STATE_ERROR_ACTIVE:

		cdev->can.state = CAN_STATE_ERROR_ACTIVE;

		break;

	case CAN_STATE_ERROR_WARNING:

		/* error warning state */

		cdev->can.can_stats.error_warning++;
@@ -841,6 +844,12 @@ static int m_can_handle_state_change(struct net_device *dev, 
	__m_can_get_berr_counter(dev, &bec);



	switch (new_state) {

	case CAN_STATE_ERROR_ACTIVE:

		cf->can_id |= CAN_ERR_CRTL | CAN_ERR_CNT;

		cf->data[1] = CAN_ERR_CRTL_ACTIVE;

		cf->data[6] = bec.txerr;

		cf->data[7] = bec.rxerr;

		break;

	case CAN_STATE_ERROR_WARNING:

		/* error warning state */

		cf->can_id |= CAN_ERR_CRTL | CAN_ERR_CNT;
@@ -877,30 +886,33 @@ static int m_can_handle_state_change(struct net_device *dev, 
	return 1;

}



static int m_can_handle_state_errors(struct net_device *dev, u32 psr)

static enum can_state

m_can_state_get_by_psr(struct m_can_classdev *cdev)

{

	struct m_can_classdev *cdev = netdev_priv(dev);

	int work_done = 0;

	u32 reg_psr;



	if (psr & PSR_EW && cdev->can.state != CAN_STATE_ERROR_WARNING) {

		netdev_dbg(dev, "entered error warning state\n");

		work_done += m_can_handle_state_change(dev,

						       CAN_STATE_ERROR_WARNING);

	}

	reg_psr = m_can_read(cdev, M_CAN_PSR);



	if (psr & PSR_EP && cdev->can.state != CAN_STATE_ERROR_PASSIVE) {

		netdev_dbg(dev, "entered error passive state\n");

		work_done += m_can_handle_state_change(dev,

						       CAN_STATE_ERROR_PASSIVE);

	}

	if (reg_psr & PSR_BO)

		return CAN_STATE_BUS_OFF;

	if (reg_psr & PSR_EP)

		return CAN_STATE_ERROR_PASSIVE;

	if (reg_psr & PSR_EW)

		return CAN_STATE_ERROR_WARNING;



	if (psr & PSR_BO && cdev->can.state != CAN_STATE_BUS_OFF) {

		netdev_dbg(dev, "entered error bus off state\n");

		work_done += m_can_handle_state_change(dev,

						       CAN_STATE_BUS_OFF);

	return CAN_STATE_ERROR_ACTIVE;

}



	return work_done;

static int m_can_handle_state_errors(struct net_device *dev)

{

	struct m_can_classdev *cdev = netdev_priv(dev);

	enum can_state new_state;



	new_state = m_can_state_get_by_psr(cdev);

	if (new_state == cdev->can.state)

		return 0;



	return m_can_handle_state_change(dev, new_state);

}



static void m_can_handle_other_err(struct net_device *dev, u32 irqstatus)
@@ -1031,8 +1043,7 @@ static int m_can_rx_handler(struct net_device *dev, int quota, u32 irqstatus) 
	}



	if (irqstatus & IR_ERR_STATE)

		work_done += m_can_handle_state_errors(dev,

						       m_can_read(cdev, M_CAN_PSR));

		work_done += m_can_handle_state_errors(dev);



	if (irqstatus & IR_ERR_BUS_30X)

		work_done += m_can_handle_bus_errors(dev, irqstatus,