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 5.10-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-.patch and it can be found in the queue-5.10 subdirectory. If you, or anyone else, feels it should not be added to the stable tree, please let <stable@xxxxxxxxxxxxxxx> know about it. commit 79c285b30816f1363c9d8bdc7c21c81a4319f227 Author: Angelo Dureghello <angelo@xxxxxxxxxxxxxxxx> Date: Tue Mar 16 00:15:10 2021 +0100 can: flexcan: flexcan_chip_freeze(): fix chip freeze for missing bitrate [ Upstream commit 47c5e474bc1e1061fb037d13b5000b38967eb070 ] 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> Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx> diff --git a/drivers/net/can/flexcan.c b/drivers/net/can/flexcan.c index d712c6fdbc87..7cbaac238ff6 100644 --- a/drivers/net/can/flexcan.c +++ b/drivers/net/can/flexcan.c @@ -658,9 +658,15 @@ static int flexcan_chip_disable(struct flexcan_priv *priv) 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 = priv->read(®s->mcr); reg |= FLEXCAN_MCR_FRZ | FLEXCAN_MCR_HALT; priv->write(reg, ®s->mcr);