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Message-Id: <20250812-m_can-fix-state-handling-v1-3-b739e06c0a3b@pengutronix.de>
Date: Tue, 12 Aug 2025 19:36:53 +0200
From: Marc Kleine-Budde <mkl@...gutronix.de>
To: Chandrasekar Ramakrishnan <rcsekar@...sung.com>,
Vincent Mailhol <mailhol.vincent@...adoo.fr>,
Patrik Flykt <patrik.flykt@...ux.intel.com>,
Dong Aisheng <b29396@...escale.com>, Fengguang Wu <fengguang.wu@...el.com>,
Varka Bhadram <varkabhadram@...il.com>, Wu Bo <wubo.oduw@...il.com>,
Markus Schneider-Pargmann <msp@...libre.com>,
Philipp Zabel <p.zabel@...gutronix.de>
Cc: linux-can@...r.kernel.org, linux-kernel@...r.kernel.org,
kernel@...gutronix.de, Marc Kleine-Budde <mkl@...gutronix.de>
Subject: [PATCH 3/7] 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: e0d1f4816f2a ("can: m_can: add Bosch M_CAN controller support")
Fixes: cd0d83eab2e0 ("can: m_can: m_can_handle_state_change(): fix state change")
Signed-off-by: Marc Kleine-Budde <mkl@...gutronix.de>
---
drivers/net/can/m_can/m_can.c | 48 ++++++++++++++++++++++++++-----------------
1 file changed, 29 insertions(+), 19 deletions(-)
diff --git a/drivers/net/can/m_can/m_can.c b/drivers/net/can/m_can/m_can.c
index a51dc0bb8124..b485d2f3d971 100644
--- a/drivers/net/can/m_can/m_can.c
+++ b/drivers/net/can/m_can/m_can.c
@@ -812,6 +812,10 @@ static int m_can_handle_state_change(struct net_device *dev,
u32 timestamp = 0;
switch (new_state) {
+ case CAN_STATE_ERROR_ACTIVE:
+ /* error active state */
+ cdev->can.state = CAN_STATE_ERROR_ACTIVE;
+ break;
case CAN_STATE_ERROR_WARNING:
/* error warning state */
cdev->can.can_stats.error_warning++;
@@ -841,6 +845,13 @@ 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:
+ /* error active state */
+ 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 +888,29 @@ static int m_can_handle_state_change(struct net_device *dev,
return 1;
}
+static enum can_state
+m_can_can_state_get_by_psr(const u32 psr)
+{
+ if (psr & PSR_BO)
+ return CAN_STATE_BUS_OFF;
+ if (psr & PSR_EP)
+ return CAN_STATE_ERROR_PASSIVE;
+ if (psr & PSR_EW)
+ return CAN_STATE_ERROR_WARNING;
+
+ return CAN_STATE_ERROR_ACTIVE;
+}
+
static int m_can_handle_state_errors(struct net_device *dev, u32 psr)
{
struct m_can_classdev *cdev = netdev_priv(dev);
- int work_done = 0;
+ enum can_state new_state;
- 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);
- }
+ new_state = m_can_can_state_get_by_psr(psr);
+ if (new_state == cdev->can.state)
+ return 0;
- 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 (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 work_done;
+ return m_can_handle_state_change(dev, new_state);
}
static void m_can_handle_other_err(struct net_device *dev, u32 irqstatus)
--
2.50.1
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