From 2c46ba4356172a2562152a21aa085d5921d9e2a2 Mon Sep 17 00:00:00 2001 From: Koen Vandeputte Date: Fri, 9 Apr 2021 15:14:37 +0200 Subject: [PATCH] kernel: backport fix for flexcan bug This patch fixes a DIV/0 error which was introduced in 4.14.225 This patch was forgotten in upstream <= 4.14 and is now queued for future release. Signed-off-by: Koen Vandeputte --- ...can_chip_freeze-fix-chip-freeze-for-.patch | 50 +++++++++++++++++++ 1 file changed, 50 insertions(+) create mode 100644 target/linux/generic/pending-4.14/840-can-flexcan-flexcan_chip_freeze-fix-chip-freeze-for-.patch diff --git a/target/linux/generic/pending-4.14/840-can-flexcan-flexcan_chip_freeze-fix-chip-freeze-for-.patch b/target/linux/generic/pending-4.14/840-can-flexcan-flexcan_chip_freeze-fix-chip-freeze-for-.patch new file mode 100644 index 0000000000..20c84617d1 --- /dev/null +++ b/target/linux/generic/pending-4.14/840-can-flexcan-flexcan_chip_freeze-fix-chip-freeze-for-.patch @@ -0,0 +1,50 @@ +From 47c5e474bc1e1061fb037d13b5000b38967eb070 Mon Sep 17 00:00:00 2001 +From: Angelo Dureghello +Date: Tue, 16 Mar 2021 00:15:10 +0100 +Subject: can: flexcan: flexcan_chip_freeze(): fix chip freeze for missing bitrate + +From: Angelo Dureghello + +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@kernel-space.org +Signed-off-by: Angelo Dureghello +[mkl: use if instead of ? operator] +Signed-off-by: Marc Kleine-Budde +Cc: Koen Vandeputte +Signed-off-by: Greg Kroah-Hartman +--- + 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 +@@ -413,9 +413,15 @@ 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); -- 2.30.2