Patch "can: flexcan: flexcan_chip_freeze(): fix chip freeze for missing bitrate" has been added to the 4.4-stable tree

[<gregkh@xxxxxxxxxxxxxxxxxxx>]

This is a note to let you know that I've just added the patch titled

    can: flexcan: flexcan_chip_freeze(): fix chip freeze for missing bitrate

to the 4.4-stable tree which can be found at:
    http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
     can-flexcan-flexcan_chip_freeze-fix-chip-freeze-for-missing-bitrate.patch
and it can be found in the queue-4.4 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.


>From 47c5e474bc1e1061fb037d13b5000b38967eb070 Mon Sep 17 00:00:00 2001
From: Angelo Dureghello <angelo@xxxxxxxxxxxxxxxx>
Date: Tue, 16 Mar 2021 00:15:10 +0100
Subject: can: flexcan: flexcan_chip_freeze(): fix chip freeze for missing bitrate

From: Angelo Dureghello <angelo@xxxxxxxxxxxxxxxx>

commit 47c5e474bc1e1061fb037d13b5000b38967eb070 upstream.

For cases when flexcan is built-in, bitrate is still not set at
registering. So flexcan_chip_freeze() generates:

[    1.860000] *** ZERO DIVIDE ***   FORMAT=4
[    1.860000] Current process id is 1
[    1.860000] BAD KERNEL TRAP: 00000000
[    1.860000] PC: [<402e70c8>] flexcan_chip_freeze+0x1a/0xa8

To allow chip freeze, using an hardcoded timeout when bitrate is still
not set.

Fixes: ec15e27cc890 ("can: flexcan: enable RX FIFO after FRZ/HALT valid")
Link: https://lore.kernel.org/r/20210315231510.650593-1-angelo@xxxxxxxxxxxxxxxx
Signed-off-by: Angelo Dureghello <angelo@xxxxxxxxxxxxxxxx>
[mkl: use if instead of ? operator]
Signed-off-by: Marc Kleine-Budde <mkl@xxxxxxxxxxxxxx>
Cc: Koen Vandeputte <koen.vandeputte@xxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
 drivers/net/can/flexcan.c |    8 +++++++-
 1 file changed, 7 insertions(+), 1 deletion(-)

--- a/drivers/net/can/flexcan.c
+++ b/drivers/net/can/flexcan.c
@@ -379,9 +379,15 @@ static int flexcan_chip_disable(struct f
 static int flexcan_chip_freeze(struct flexcan_priv *priv)
 {
 	struct flexcan_regs __iomem *regs = priv->regs;
-	unsigned int timeout = 1000 * 1000 * 10 / priv->can.bittiming.bitrate;
+	unsigned int timeout;
+	u32 bitrate = priv->can.bittiming.bitrate;
 	u32 reg;
 
+	if (bitrate)
+		timeout = 1000 * 1000 * 10 / bitrate;
+	else
+		timeout = FLEXCAN_TIMEOUT_US / 10;
+
 	reg = flexcan_read(&regs->mcr);
 	reg |= FLEXCAN_MCR_FRZ | FLEXCAN_MCR_HALT;
 	flexcan_write(reg, &regs->mcr);


Patches currently in stable-queue which might be from angelo@xxxxxxxxxxxxxxxx are

queue-4.4/can-flexcan-flexcan_chip_freeze-fix-chip-freeze-for-missing-bitrate.patch