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spi: fix the divide by 0 error when calculating xfer waiting time

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[ 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
Signed-off-by: Mark Brown <broonie@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
This commit is contained in:
Xu Yilun 2021-01-04 09:29:09 +08:00 committed by Greg Kroah-Hartman
parent 17a08680ab
commit 501e1875da
1 changed files with 5 additions and 1 deletions
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6
drivers/spi/spi.c
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@ -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)