[ 3.8.y.z extended stable ] Patch "can: flexcan: fix flexcan_chip_start() on imx6" has been added to staging queue

[Kamal Mostafa]

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

    can: flexcan: fix flexcan_chip_start() on imx6

to the linux-3.8.y-queue branch of the 3.8.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-3.8.y-queue

This patch is scheduled to be released in version 3.8.13.11.

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

For more information about the 3.8.y.z tree, see
https://wiki.ubuntu.com/Kernel/Dev/ExtendedStable

Thanks.
-Kamal

------

>From 135726d29a4ebaf3285bc4fa0d3346cb75679485 Mon Sep 17 00:00:00 2001
From: Marc Kleine-Budde <mkl at pengutronix.de>
Date: Fri, 27 Sep 2013 12:15:05 +0200
Subject: can: flexcan: fix flexcan_chip_start() on imx6
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

commit 0d1862ea1a5bb876cf05555a7307080cb75bf379 upstream.

In the flexcan_chip_start() function first the flexcan core is going through
the soft reset sequence, then the RX FIFO is enabled.

With the hardware is put into FIFO mode, message buffers 1...7 are reserved by
the FIFO engine. The remaining message buffers are in reset default values.
This patch removes the bogus initialization of the message buffers, as it
causes an imprecise external abort on imx6.

Reported-by: Lothar Waßmann <LW at KARO-electronics.de>
Tested-by: Lothar Waßmann <LW at KARO-electronics.de>
Signed-off-by: Marc Kleine-Budde <mkl at pengutronix.de>
Signed-off-by: Kamal Mostafa <kamal at canonical.com>
---
 drivers/net/can/flexcan.c | 12 ------------
 1 file changed, 12 deletions(-)

diff --git a/drivers/net/can/flexcan.c b/drivers/net/can/flexcan.c
index 0289a6d..15d5abb 100644
--- a/drivers/net/can/flexcan.c
+++ b/drivers/net/can/flexcan.c
@@ -707,7 +707,6 @@ static int flexcan_chip_start(struct net_device *dev)
 {
 	struct flexcan_priv *priv = netdev_priv(dev);
 	struct flexcan_regs __iomem *regs = priv->base;
-	unsigned int i;
 	int err;
 	u32 reg_mcr, reg_ctrl;

@@ -777,17 +776,6 @@ static int flexcan_chip_start(struct net_device *dev)
 	netdev_dbg(dev, "%s: writing ctrl=0x%08x", __func__, reg_ctrl);
 	flexcan_write(reg_ctrl, &regs->ctrl);

-	for (i = 0; i < ARRAY_SIZE(regs->cantxfg); i++) {
-		flexcan_write(0, &regs->cantxfg[i].can_ctrl);
-		flexcan_write(0, &regs->cantxfg[i].can_id);
-		flexcan_write(0, &regs->cantxfg[i].data[0]);
-		flexcan_write(0, &regs->cantxfg[i].data[1]);
-
-		/* put MB into rx queue */
-		flexcan_write(FLEXCAN_MB_CNT_CODE(0x4),
-			&regs->cantxfg[i].can_ctrl);
-	}
-
 	/* acceptance mask/acceptance code (accept everything) */
 	flexcan_write(0x0, &regs->rxgmask);
 	flexcan_write(0x0, &regs->rx14mask);
--
1.8.1.2