[PATCH 3.5 13/71] can: flexcan: fix shutdown: first disable chip, then all interrupts

[Luis Henriques]

3.5.7.33 -stable review patch.  If anyone has any objections, please let me know.

------------------

From: Marc Kleine-Budde <mkl at pengutronix.de>

commit 5be93bdda64e85450598c6e97f79fb8f6acf30e0 upstream.

When shutting down the CAN interface (ifconfig canX down) during high CAN bus
loads, the CAN core might hang and freeze the whole CPU.

This patch fixes the shutdown sequence by first disabling the CAN core then
disabling all interrupts.

Signed-off-by: Marc Kleine-Budde <mkl at pengutronix.de>
[ luis: backported to 3.5: adjusted context ]
Signed-off-by: Luis Henriques <luis.henriques at canonical.com>
---
 drivers/net/can/flexcan.c | 8 +++++---
 1 file changed, 5 insertions(+), 3 deletions(-)

diff --git a/drivers/net/can/flexcan.c b/drivers/net/can/flexcan.c
index 2bf507b..95109eb 100644
--- a/drivers/net/can/flexcan.c
+++ b/drivers/net/can/flexcan.c
@@ -779,14 +779,16 @@ static void flexcan_chip_stop(struct net_device *dev)
 	struct flexcan_regs __iomem *regs = priv->base;
 	u32 reg;
 
-	/* Disable all interrupts */
-	flexcan_write(0, &regs->imask1);
-
 	/* Disable + halt module */
 	reg = flexcan_read(&regs->mcr);
 	reg |= FLEXCAN_MCR_MDIS | FLEXCAN_MCR_HALT;
 	flexcan_write(reg, &regs->mcr);
 
+	/* Disable all interrupts */
+	flexcan_write(0, &regs->imask1);
+	flexcan_write(priv->reg_ctrl_default & ~FLEXCAN_CTRL_ERR_ALL,
+		      &regs->ctrl);
+
 	flexcan_transceiver_switch(priv, 0);
 	priv->can.state = CAN_STATE_STOPPED;
 
-- 
1.9.1