[3.5.y.z extended stable] Patch "can: flexcan: fix shutdown: first disable chip, then all interrupts" has been added to staging queue

[Luis Henriques]

This is a note to let you know that I have just added a patch titled

    can: flexcan: fix shutdown: first disable chip, then all interrupts

to the linux-3.5.y-queue branch of the 3.5.y.z extended stable tree 
which can be found at:

 http://kernel.ubuntu.com/git?p=ubuntu/linux.git;a=shortlog;h=refs/heads/linux-3.5.y-queue

If you, or anyone else, feels it should not be added to this tree, please 
reply to this email.

For more information about the 3.5.y.z tree, see
https://wiki.ubuntu.com/Kernel/Dev/ExtendedStable

Thanks.
-Luis

------

>From e19740cbfde6819351eee19f2e3d397cc32e809d Mon Sep 17 00:00:00 2001
From: Marc Kleine-Budde <mkl at pengutronix.de>
Date: Wed, 19 Feb 2014 12:00:51 +0100
Subject: can: flexcan: fix shutdown: first disable chip, then all interrupts

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;

--
1.9.0