From: Sangwook Shin Date: Mon, 18 Aug 2025 02:18:23 +0000 (+0900) Subject: watchdog: s3c2410_wdt: Fix max_timeout being calculated larger X-Git-Tag: v6.18-rc1~59^2~9 X-Git-Url: http://git.ipfire.org/?a=commitdiff_plain;h=df3c6e0b6d83450563d6266e1dacc7eaf25511f4;p=thirdparty%2Fkernel%2Fstable.git watchdog: s3c2410_wdt: Fix max_timeout being calculated larger 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. Reviewed-by: Sam Protsenko Signed-off-by: Sangwook Shin Reviewed-by: Guenter Roeck Signed-off-by: Guenter Roeck Signed-off-by: Wim Van Sebroeck --- diff --git a/drivers/watchdog/s3c2410_wdt.c b/drivers/watchdog/s3c2410_wdt.c index 95f7207e390a..1e8cf0299713 100644 --- a/drivers/watchdog/s3c2410_wdt.c +++ b/drivers/watchdog/s3c2410_wdt.c @@ -27,6 +27,7 @@ #include #include #include +#include #define S3C2410_WTCON 0x00 #define S3C2410_WTDAT 0x04 @@ -410,9 +411,14 @@ 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); + const u64 n_max = (u64)(S3C2410_WTCON_PRESCALE_MAX + 1) * + S3C2410_WTCON_MAXDIV * S3C2410_WTCNT_MAXCNT; + u64 t_max = div64_ul(n_max, 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)