linux-kernel - [PATCH 4.19 31/74] can: m_can: Disable and ignore ELO interrupt

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Date:   Mon, 13 Dec 2021 10:30:02 +0100
From:   Greg Kroah-Hartman <gregkh@...uxfoundation.org>
To:     linux-kernel@...r.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        stable@...r.kernel.org,
        Brian Silverman <brian.silverman@...erivertech.com>,
        Marc Kleine-Budde <mkl@...gutronix.de>
Subject: [PATCH 4.19 31/74] can: m_can: Disable and ignore ELO interrupt

From: Brian Silverman <brian.silverman@...erivertech.com>

commit f58ac1adc76b5beda43c64ef359056077df4d93a upstream.

With the design of this driver, this condition is often triggered.
However, the counter that this interrupt indicates an overflow is never
read either, so overflowing is harmless.

On my system, when a CAN bus starts flapping up and down, this locks up
the whole system with lots of interrupts and printks.

Specifically, this interrupt indicates the CEL field of ECR has
overflowed. All reads of ECR mask out CEL.

Fixes: e0d1f4816f2a ("can: m_can: add Bosch M_CAN controller support")
Link: https://lore.kernel.org/all/20211129222628.7490-1-brian.silverman@bluerivertech.com
Cc: stable@...r.kernel.org
Signed-off-by: Brian Silverman <brian.silverman@...erivertech.com>
Signed-off-by: Marc Kleine-Budde <mkl@...gutronix.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@...uxfoundation.org>

---
 drivers/net/can/m_can/m_can.c |   14 ++++++--------
 1 file changed, 6 insertions(+), 8 deletions(-)

--- a/drivers/net/can/m_can/m_can.c
+++ b/drivers/net/can/m_can/m_can.c
@@ -233,15 +233,15 @@ enum m_can_mram_cfg {
 
 /* Interrupts for version 3.0.x */
 #define IR_ERR_LEC_30X	(IR_STE	| IR_FOE | IR_ACKE | IR_BE | IR_CRCE)
-#define IR_ERR_BUS_30X	(IR_ERR_LEC_30X | IR_WDI | IR_ELO | IR_BEU | \
-			 IR_BEC | IR_TOO | IR_MRAF | IR_TSW | IR_TEFL | \
-			 IR_RF1L | IR_RF0L)
+#define IR_ERR_BUS_30X	(IR_ERR_LEC_30X | IR_WDI | IR_BEU | IR_BEC | \
+			 IR_TOO | IR_MRAF | IR_TSW | IR_TEFL | IR_RF1L | \
+			 IR_RF0L)
 #define IR_ERR_ALL_30X	(IR_ERR_STATE | IR_ERR_BUS_30X)
 /* Interrupts for version >= 3.1.x */
 #define IR_ERR_LEC_31X	(IR_PED | IR_PEA)
-#define IR_ERR_BUS_31X      (IR_ERR_LEC_31X | IR_WDI | IR_ELO | IR_BEU | \
-			 IR_BEC | IR_TOO | IR_MRAF | IR_TSW | IR_TEFL | \
-			 IR_RF1L | IR_RF0L)
+#define IR_ERR_BUS_31X      (IR_ERR_LEC_31X | IR_WDI | IR_BEU | IR_BEC | \
+			 IR_TOO | IR_MRAF | IR_TSW | IR_TEFL | IR_RF1L | \
+			 IR_RF0L)
 #define IR_ERR_ALL_31X	(IR_ERR_STATE | IR_ERR_BUS_31X)
 
 /* Interrupt Line Select (ILS) */
@@ -769,8 +769,6 @@ static void m_can_handle_other_err(struc
 {
 	if (irqstatus & IR_WDI)
 		netdev_err(dev, "Message RAM Watchdog event due to missing READY\n");
-	if (irqstatus & IR_ELO)
-		netdev_err(dev, "Error Logging Overflow\n");
 	if (irqstatus & IR_BEU)
 		netdev_err(dev, "Bit Error Uncorrected\n");
 	if (irqstatus & IR_BEC)