6.10-stable review patch. If anyone has any objections, please let me know.
------------------
From: Markus Schneider-Pargmann <msp@xxxxxxxxxxxx>
[ Upstream commit a651261ac74298535f6d6316ebe27beceb6b17b1 ]
During resume the interrupts are limited to IR_RF0N and the chip keeps
running. In this case if coalescing is enabled and active we may miss
waterlevel interrupts during suspend. It is safer to reset the
coalescing by stopping the timer and adding IR_RF0N | IR_TEFN to the
interrupts.
This is a theoratical issue and probably extremely rare.
Cc: Martin Hundebøll <martin@xxxxxxxxxx>
Fixes: 4a94d7e31cf5 ("can: m_can: allow keeping the transceiver running in suspend")
Signed-off-by: Markus Schneider-Pargmann <msp@xxxxxxxxxxxx>
Link: https://lore.kernel.org/all/20240805183047.305630-2-msp@xxxxxxxxxxxx
Signed-off-by: Marc Kleine-Budde <mkl@xxxxxxxxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
---
drivers/net/can/m_can/m_can.c | 16 +++++++++++++---
1 file changed, 13 insertions(+), 3 deletions(-)
diff --git a/drivers/net/can/m_can/m_can.c b/drivers/net/can/m_can/m_can.c
index 205a6cb4470f..257d5bc0ae9e 100644
--- a/drivers/net/can/m_can/m_can.c
+++ b/drivers/net/can/m_can/m_can.c
@@ -2387,12 +2387,15 @@ int m_can_class_suspend(struct device *dev)
netif_device_detach(ndev);
/* leave the chip running with rx interrupt enabled if it is
- * used as a wake-up source.
+ * used as a wake-up source. Coalescing needs to be reset then,
+ * the timer is cancelled here, interrupts are done in resume.
*/
- if (cdev->pm_wake_source)
+ if (cdev->pm_wake_source) {
+ hrtimer_cancel(&cdev->hrtimer);
m_can_write(cdev, M_CAN_IE, IR_RF0N);
- else
+ } else {
m_can_stop(ndev);
+ }
m_can_clk_stop(cdev);
}
@@ -2422,6 +2425,13 @@ int m_can_class_resume(struct device *dev)
return ret;
if (cdev->pm_wake_source) {
+ /* Restore active interrupts but disable coalescing as
+ * we may have missed important waterlevel interrupts
+ * between suspend and resume. Timers are already
+ * stopped in suspend. Here we enable all interrupts
+ * again.
+ */
+ cdev->active_interrupts |= IR_RF0N | IR_TEFN;
m_can_write(cdev, M_CAN_IE, cdev->active_interrupts);
} else {
ret = m_can_start(ndev);
--
2.43.0
