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Subject[PATCH] watchdog: dw_wdt: fix overflow issue in dw_wdt_top_in_seconds
Date
If top is 15, (1 << (16 + top)) may be negative.

Change-Id: I76e4a603a54f093e64a4b266008570e3afcdb35a
Signed-off-by: Huibin Hong <huibin.hong@rock-chips.com>
---
drivers/watchdog/dw_wdt.c | 4 +++-
1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/drivers/watchdog/dw_wdt.c b/drivers/watchdog/dw_wdt.c
index 6ea0634..059c974 100644
--- a/drivers/watchdog/dw_wdt.c
+++ b/drivers/watchdog/dw_wdt.c
@@ -81,7 +81,9 @@ static inline int dw_wdt_top_in_seconds(unsigned top)
* There are 16 possible timeout values in 0..15 where the number of
* cycles is 2 ^ (16 + i) and the watchdog counts down.
*/
- return (1 << (16 + top)) / clk_get_rate(dw_wdt.clk);
+ unsigned int cycles = 1 << (16 + top);
+
+ return cycles / clk_get_rate(dw_wdt.clk);
}

static int dw_wdt_get_top(void)
--
1.9.1

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