FAILED: patch "[PATCH] can: flexcan: fix transition from and to freeze mode in" failed to apply to 3.13-stable tree

[<gregkh@xxxxxxxxxxxxxxxxxxx>]

The patch below does not apply to the 3.13-stable tree.
If someone wants it applied there, or to any other stable or longterm
tree, then please email the backport, including the original git commit
id to <stable@xxxxxxxxxxxxxxx>.

thanks,

greg k-h

------------------ original commit in Linus's tree ------------------

>From b1aa1c7a2165b44ecce66286a3095cc6c7667d1c Mon Sep 17 00:00:00 2001
From: Marc Kleine-Budde <mkl@xxxxxxxxxxxxxx>
Date: Fri, 28 Feb 2014 17:08:21 +0100
Subject: [PATCH] can: flexcan: fix transition from and to freeze mode in
 chip_{,un}freeze

This patch factors out freeze and unfreeze of the CAN core into seperate
functions. Experiments have shown that the transition from and to freeze mode
may take several microseconds, especially the time entering the freeze mode
depends on the current bitrate.

This patch adds a while loop which polls the Freeze Mode ACK bit (FRZ_ACK) that
indicates a successfull mode change. If the function runs into a timeout a
error value is returned.

Cc: linux-stable <stable@xxxxxxxxxxxxxxx>
Signed-off-by: Marc Kleine-Budde <mkl@xxxxxxxxxxxxxx>

diff --git a/drivers/net/can/flexcan.c b/drivers/net/can/flexcan.c
index 6b0fecd0a6ad..330b5b957a39 100644
--- a/drivers/net/can/flexcan.c
+++ b/drivers/net/can/flexcan.c
@@ -325,6 +325,44 @@ static int flexcan_chip_disable(struct flexcan_priv *priv)
 	return 0;
 }
 
+static int flexcan_chip_freeze(struct flexcan_priv *priv)
+{
+	struct flexcan_regs __iomem *regs = priv->base;
+	unsigned int timeout = 1000 * 1000 * 10 / priv->can.bittiming.bitrate;
+	u32 reg;
+
+	reg = flexcan_read(&regs->mcr);
+	reg |= FLEXCAN_MCR_HALT;
+	flexcan_write(reg, &regs->mcr);
+
+	while (timeout-- && !(flexcan_read(&regs->mcr) & FLEXCAN_MCR_FRZ_ACK))
+		usleep_range(100, 200);
+
+	if (!(flexcan_read(&regs->mcr) & FLEXCAN_MCR_FRZ_ACK))
+		return -ETIMEDOUT;
+
+	return 0;
+}
+
+static int flexcan_chip_unfreeze(struct flexcan_priv *priv)
+{
+	struct flexcan_regs __iomem *regs = priv->base;
+	unsigned int timeout = FLEXCAN_TIMEOUT_US / 10;
+	u32 reg;
+
+	reg = flexcan_read(&regs->mcr);
+	reg &= ~FLEXCAN_MCR_HALT;
+	flexcan_write(reg, &regs->mcr);
+
+	while (timeout-- && (flexcan_read(&regs->mcr) & FLEXCAN_MCR_FRZ_ACK))
+		usleep_range(10, 20);
+
+	if (flexcan_read(&regs->mcr) & FLEXCAN_MCR_FRZ_ACK)
+		return -ETIMEDOUT;
+
+	return 0;
+}
+
 static int flexcan_get_berr_counter(const struct net_device *dev,
 				    struct can_berr_counter *bec)
 {
@@ -756,7 +794,7 @@ static int flexcan_chip_start(struct net_device *dev)
 		netdev_err(dev, "Failed to softreset can module (mcr=0x%08x)\n",
 			   reg_mcr);
 		err = -ENODEV;
-		goto out;
+		goto out_chip_disable;
 	}
 
 	flexcan_set_bittiming(dev);
@@ -826,12 +864,12 @@ static int flexcan_chip_start(struct net_device *dev)
 
 	err = flexcan_transceiver_enable(priv);
 	if (err)
-		goto out;
+		goto out_chip_disable;
 
 	/* synchronize with the can bus */
-	reg_mcr = flexcan_read(&regs->mcr);
-	reg_mcr &= ~FLEXCAN_MCR_HALT;
-	flexcan_write(reg_mcr, &regs->mcr);
+	err = flexcan_chip_unfreeze(priv);
+	if (err)
+		goto out_transceiver_disable;
 
 	priv->can.state = CAN_STATE_ERROR_ACTIVE;
 
@@ -844,7 +882,9 @@ static int flexcan_chip_start(struct net_device *dev)
 
 	return 0;
 
- out:
+ out_transceiver_disable:
+	flexcan_transceiver_disable(priv);
+ out_chip_disable:
 	flexcan_chip_disable(priv);
 	return err;
 }
@@ -859,12 +899,10 @@ static void flexcan_chip_stop(struct net_device *dev)
 {
 	struct flexcan_priv *priv = netdev_priv(dev);
 	struct flexcan_regs __iomem *regs = priv->base;
-	u32 reg;
 
-	/* Disable + halt module */
-	reg = flexcan_read(&regs->mcr);
-	reg |= FLEXCAN_MCR_MDIS | FLEXCAN_MCR_HALT;
-	flexcan_write(reg, &regs->mcr);
+	/* freeze + disable module */
+	flexcan_chip_freeze(priv);
+	flexcan_chip_disable(priv);
 
 	/* Disable all interrupts */
 	flexcan_write(0, &regs->imask1);

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