[PATCH 4.9 12/92] watchdog: imx2_wdt: fix min() calculation in imx2_wdt_set_timeout

From: Greg Kroah-Hartman
Date: Wed Oct 16 2019 - 18:16:47 EST


From: Rasmus Villemoes <linux@xxxxxxxxxxxxxxxxxx>

commit 144783a80cd2cbc45c6ce17db649140b65f203dd upstream.

Converting from ms to s requires dividing by 1000, not multiplying. So
this is currently taking the smaller of new_timeout and 1.28e8,
i.e. effectively new_timeout.

The driver knows what it set max_hw_heartbeat_ms to, so use that
value instead of doing a division at run-time.

FWIW, this can easily be tested by booting into a busybox shell and
doing "watchdog -t 5 -T 130 /dev/watchdog" - without this patch, the
watchdog fires after 130&127 == 2 seconds.

Fixes: b07e228eee69 "watchdog: imx2_wdt: Fix set_timeout for big timeout values"
Cc: stable@xxxxxxxxxxxxxxx # 5.2 plus anything the above got backported to
Signed-off-by: Rasmus Villemoes <linux@xxxxxxxxxxxxxxxxxx>
Reviewed-by: Guenter Roeck <linux@xxxxxxxxxxxx>
Link: https://lore.kernel.org/r/20190812131356.23039-1-linux@xxxxxxxxxxxxxxxxxx
Signed-off-by: Guenter Roeck <linux@xxxxxxxxxxxx>
Signed-off-by: Wim Van Sebroeck <wim@xxxxxxxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>

---
drivers/watchdog/imx2_wdt.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)

--- a/drivers/watchdog/imx2_wdt.c
+++ b/drivers/watchdog/imx2_wdt.c
@@ -58,7 +58,7 @@

#define IMX2_WDT_WMCR 0x08 /* Misc Register */

-#define IMX2_WDT_MAX_TIME 128
+#define IMX2_WDT_MAX_TIME 128U
#define IMX2_WDT_DEFAULT_TIME 60 /* in seconds */

#define WDOG_SEC_TO_COUNT(s) ((s * 2 - 1) << 8)
@@ -183,7 +183,7 @@ static int imx2_wdt_set_timeout(struct w
{
unsigned int actual;

- actual = min(new_timeout, wdog->max_hw_heartbeat_ms * 1000);
+ actual = min(new_timeout, IMX2_WDT_MAX_TIME);
__imx2_wdt_set_timeout(wdog, actual);
wdog->timeout = new_timeout;
return 0;