[PATCH v5 2/5] watchdog: s3c2410_wdt: Fix max_timeout being calculated larger
From: Sangwook Shin <hidden>
Date: 2025-08-06 07:00:33
Also in:
linux-samsung-soc, linux-watchdog, lkml
Subsystem:
arm/samsung s3c, s5p and exynos arm architectures, the rest, watchdog device drivers · Maintainers:
Krzysztof Kozlowski, Peter Griffin, Linus Torvalds, Wim Van Sebroeck, Guenter Roeck
Fix the issue of max_timeout being calculated larger than actual value. The calculation result of freq / (S3C2410_WTCON_PRESCALE_MAX + 1) / S3C2410_WTCON_MAXDIV is smaller than the actual value because the remainder is discarded during the calculation process. This leads to a larger calculated value for max_timeout compared to the actual settable value. To resolve this issue, the order of calculations in the computation process has been adjusted. Signed-off-by: Sangwook Shin <redacted> --- drivers/watchdog/s3c2410_wdt.c | 9 +++++++-- 1 file changed, 7 insertions(+), 2 deletions(-)
diff --git a/drivers/watchdog/s3c2410_wdt.c b/drivers/watchdog/s3c2410_wdt.c
index 95f7207e390a..0a4c0ab2a3d6 100644
--- a/drivers/watchdog/s3c2410_wdt.c
+++ b/drivers/watchdog/s3c2410_wdt.c@@ -27,6 +27,7 @@ #include <linux/mfd/syscon.h> #include <linux/regmap.h> #include <linux/delay.h> +#include <linux/math64.h> #define S3C2410_WTCON 0x00 #define S3C2410_WTDAT 0x04
@@ -410,9 +411,13 @@ static inline unsigned long s3c2410wdt_get_freq(struct s3c2410_wdt *wdt) static inline unsigned int s3c2410wdt_max_timeout(struct s3c2410_wdt *wdt) { const unsigned long freq = s3c2410wdt_get_freq(wdt); + //(S3C2410_WTCON_PRESCALE_MAX + 1) * S3C2410_WTCON_MAXDIV = 0x8000 + u64 t_max = div64_ul((u64)S3C2410_WTCNT_MAXCNT * 0x8000, freq); - return S3C2410_WTCNT_MAXCNT / (freq / (S3C2410_WTCON_PRESCALE_MAX + 1) - / S3C2410_WTCON_MAXDIV); + if (t_max > UINT_MAX) + t_max = UINT_MAX; + + return t_max; } static int s3c2410wdt_disable_wdt_reset(struct s3c2410_wdt *wdt, bool mask)
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2.25.1