[PATCH 5.10 078/152] spi: fix the divide by 0 error when calculating xfer waiting time
From: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Date: 2021-01-18 11:56:57
Also in:
lkml
Subsystem:
spi subsystem, the rest · Maintainers:
Mark Brown, Linus Torvalds
From: Xu Yilun <yilun.xu@intel.com> [ Upstream commit 6170d077bf92c5b3dfbe1021688d3c0404f7c9e9 ] The xfer waiting time is the result of xfer->len / xfer->speed_hz. This patch makes the assumption of 100khz xfer speed if the xfer->speed_hz is not assigned and stays 0. This avoids the divide by 0 issue and ensures a reasonable tolerant waiting time. Signed-off-by: Xu Yilun <yilun.xu@intel.com> Link: https://lore.kernel.org/r/1609723749-3557-1-git-send-email-yilun.xu@intel.com (local) Signed-off-by: Mark Brown <broonie@kernel.org> Signed-off-by: Sasha Levin <sashal@kernel.org> --- drivers/spi/spi.c | 6 +++++- 1 file changed, 5 insertions(+), 1 deletion(-)
diff --git a/drivers/spi/spi.c b/drivers/spi/spi.c
index 2eaa7dbb70108..7694e1ae5b0b2 100644
--- a/drivers/spi/spi.c
+++ b/drivers/spi/spi.c@@ -1100,6 +1100,7 @@ static int spi_transfer_wait(struct spi_controller *ctlr, { struct spi_statistics *statm = &ctlr->statistics; struct spi_statistics *stats = &msg->spi->statistics; + u32 speed_hz = xfer->speed_hz; unsigned long long ms; if (spi_controller_is_slave(ctlr)) {
@@ -1108,8 +1109,11 @@ static int spi_transfer_wait(struct spi_controller *ctlr, return -EINTR; } } else { + if (!speed_hz) + speed_hz = 100000; + ms = 8LL * 1000LL * xfer->len; - do_div(ms, xfer->speed_hz); + do_div(ms, speed_hz); ms += ms + 200; /* some tolerance */ if (ms > UINT_MAX)
--
2.27.0