From 39ecbfcce0c7bda0fba37e4dfca520927513f4ca Mon Sep 17 00:00:00 2001 From: Matthias Kaehlcke Date: Tue, 9 Mar 2010 22:13:20 +0100 Subject: [PATCH] ep93xx timer: Fix possible overflow in usecs_to_ticks() ep93xx timer: Use 64-bit values in usecs_to_ticks() in order to avoid overflows in intermediate values Signed-off-by: Matthias Kaehlcke --- cpu/arm920t/ep93xx/timer.c | 16 ++++------------ 1 file changed, 4 insertions(+), 12 deletions(-) diff --git a/cpu/arm920t/ep93xx/timer.c b/cpu/arm920t/ep93xx/timer.c index b1a01a0..bc4ec8f 100644 --- a/cpu/arm920t/ep93xx/timer.c +++ b/cpu/arm920t/ep93xx/timer.c @@ -36,7 +36,7 @@ #define TIMER_CLKSEL (1 << 3) #define TIMER_ENABLE (1 << 7) -#define TIMER_FREQ 508469 +#define TIMER_FREQ 508469 /* ticks / second */ #define TIMER_MAX_VAL 0xFFFFFFFF static struct ep93xx_timer @@ -53,18 +53,10 @@ static inline unsigned long clk_to_systicks(unsigned long long clk_ticks) return (unsigned long)sys_ticks; } -static inline unsigned long usecs_to_ticks(unsigned long usecs) +static inline unsigned long long usecs_to_ticks(unsigned long usecs) { - unsigned long ticks; - - if (usecs >= 1000) { - ticks = usecs / 1000; - ticks *= TIMER_FREQ; - ticks /= 1000; - } else { - ticks = usecs * TIMER_FREQ; - ticks /= (1000 * 1000); - } + unsigned long long ticks = (unsigned long long)usecs * TIMER_FREQ; + do_div(ticks, 1000 * 1000); return ticks; }