[PATCH 5.13 087/223] spi: spi-cadence-quadspi: Fix division by zero warning

From: Greg Kroah-Hartman
Date: Mon Jul 26 2021 - 12:30:08 EST


From: Yoshitaka Ikeda <ikeda@xxxxxxxxxxxx>

[ Upstream commit 55cef88bbf12f3bfbe5c2379a8868a034707e755 ]

Fix below division by zero warning:
- Added an if statement because buswidth can be zero, resulting in division by zero.
- The modified code was based on another driver (atmel-quadspi).

[ 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>
Link: https://lore.kernel.org/r/ed989af6-da88-4e0b-9ed8-126db6cad2e4@xxxxxxxxxxxx
Signed-off-by: Mark Brown <broonie@xxxxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
---
drivers/spi/spi-cadence-quadspi.c | 10 ++++++----
1 file changed, 6 insertions(+), 4 deletions(-)

diff --git a/drivers/spi/spi-cadence-quadspi.c b/drivers/spi/spi-cadence-quadspi.c
index 7a00346ff9b9..13d1f0ce618e 100644
--- a/drivers/spi/spi-cadence-quadspi.c
+++ b/drivers/spi/spi-cadence-quadspi.c
@@ -307,11 +307,13 @@ static unsigned int cqspi_calc_rdreg(struct cqspi_flash_pdata *f_pdata)

static unsigned int cqspi_calc_dummy(const struct spi_mem_op *op, bool dtr)
{
- unsigned int dummy_clk;
+ unsigned int dummy_clk = 0;

- dummy_clk = op->dummy.nbytes * (8 / op->dummy.buswidth);
- if (dtr)
- dummy_clk /= 2;
+ if (op->dummy.buswidth && op->dummy.nbytes) {
+ dummy_clk = op->dummy.nbytes * (8 / op->dummy.buswidth);
+ if (dtr)
+ dummy_clk /= 2;
+ }

return dummy_clk;
}
--
2.30.2