This is a note to let you know that I've just added the patch titled
spi: spi-cadence-quadspi: Fix division by zero warning
to the 5.13-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:
spi-spi-cadence-quadspi-fix-division-by-zero-warning-try2.patch
and it can be found in the queue-5.13 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
>From 0e85ee897858b1c7a5de53f496d016899d9639c5 Mon Sep 17 00:00:00 2001
From: Yoshitaka Ikeda <ikeda@xxxxxxxxxxxx>
Date: Fri, 16 Jul 2021 14:35:13 +0000
Subject: spi: spi-cadence-quadspi: Fix division by zero warning
From: Yoshitaka Ikeda <ikeda@xxxxxxxxxxxx>
commit 0e85ee897858b1c7a5de53f496d016899d9639c5 upstream.
Fix below division by zero warning:
- The reason for dividing by zero is because the dummy bus width is zero,
but if the dummy n bytes is zero, it indicates that there is no data transfer,
so we can just return zero without doing any calculations.
[ 0.795337] Division by zero in kernel.
:
[ 0.834051] [<807fd40c>] (__div0) from [<804e1acc>] (Ldiv0+0x8/0x10)
[ 0.839097] [<805f0710>] (cqspi_exec_mem_op) from [<805edb4c>] (spi_mem_exec_op+0x3b0/0x3f8)
Fixes: 7512eaf54190 ("spi: cadence-quadspi: Fix dummy cycle calculation when buswidth > 1")
Signed-off-by: Yoshitaka Ikeda <ikeda@xxxxxxxxxxxx>
Reviewed-by: Pratyush Yadav <p.yadav@xxxxxx>
Link: https://lore.kernel.org/r/92eea403-9b21-2488-9cc1-664bee760c5e@xxxxxxxxxxxx
Signed-off-by: Mark Brown <broonie@xxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
drivers/spi/spi-cadence-quadspi.c | 3 +++
1 file changed, 3 insertions(+)
--- a/drivers/spi/spi-cadence-quadspi.c
+++ b/drivers/spi/spi-cadence-quadspi.c
@@ -309,6 +309,9 @@ static unsigned int cqspi_calc_dummy(con
{
unsigned int dummy_clk;
+ if (!op->dummy.nbytes)
+ return 0;
+
dummy_clk = op->dummy.nbytes * (8 / op->dummy.buswidth);
if (dtr)
dummy_clk /= 2;
Patches currently in stable-queue which might be from ikeda@xxxxxxxxxxxx are
queue-5.13/spi-spi-cadence-quadspi-fix-division-by-zero-warning-try2.patch
queue-5.13/spi-spi-cadence-quadspi-fix-division-by-zero-warning.patch
queue-5.13/spi-spi-cadence-quadspi-revert-fix-division-by-zero-warning.patch
