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 4.9-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-4.9 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(®s->mcr); reg |= FLEXCAN_MCR_FRZ | FLEXCAN_MCR_HALT; flexcan_write(reg, ®s->mcr); Patches currently in stable-queue which might be from angelo@xxxxxxxxxxxxxxxx are queue-4.9/can-flexcan-flexcan_chip_freeze-fix-chip-freeze-for-missing-bitrate.patch