can: m_can: process interrupt only when not runtime suspended

[ Upstream commit a1f634463aaf2c94dfa13001dbdea011303124cc ]

Avoid processing bogus interrupt statuses when the HW is runtime suspended and
the M_CAN_IR register read may get all bits 1's. Handler can be called if the
interrupt request is shared with other peripherals or at the end of free_irq().

Therefore check the runtime suspended status before processing.

Fixes: cdf8259d6573 ("can: m_can: Add PM Support")
Signed-off-by: Jarkko Nikula <jarkko.nikula@linux.intel.com>
Link: https://lore.kernel.org/r/20200915134715.696303-1-jarkko.nikula@linux.intel.com
Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>
Signed-off-by: Sasha Levin <sashal@kernel.org>

diff --git a/drivers/net/can/m_can/m_can.c b/drivers/net/can/m_can/m_can.c
index 661db85d569ceba5783577a0212a604de4737400..246fa2657d744cf131d55c35ead0105c9dd2cd60 100644 (file)
--- a/drivers/net/can/m_can/m_can.c
+++ b/drivers/net/can/m_can/m_can.c
@@ -913,6 +913,8 @@ static irqreturn_t m_can_isr(int irq, void *dev_id)
        struct net_device_stats *stats = &dev->stats;
        u32 ir;
 
+       if (pm_runtime_suspended(cdev->dev))
+               return IRQ_NONE;
        ir = m_can_read(cdev, M_CAN_IR);
        if (!ir)
                return IRQ_NONE;