ep93xx timer: Use 64-bit values in usecs_to_ticks() in order to avoid
overflows in intermediate values
Signed-off-by: Matthias Kaehlcke <matth...@kaehlcke.net>
---
cpu/arm920t/ep93xx/timer.c | 16 ++++------------
1 files 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;
}
--
1.6.5
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