* [PATCH] watchdog: davinci: Use div64_ul instead of do_div
@ 2021-11-25 1:49 cgel.zte
2021-11-25 2:33 ` Guenter Roeck
0 siblings, 1 reply; 2+ messages in thread
From: cgel.zte @ 2021-11-25 1:49 UTC (permalink / raw)
To: wim; +Cc: linux, linux-watchdog, linux-kernel, Changcheng Deng, Zeal Robot
From: Changcheng Deng <deng.changcheng@zte.com.cn>
do_div() does a 64-by-32 division. Here the divisor is an unsigned long
which on some platforms is 64 bit wide. So use div64_ul instead of do_div
to avoid a possible truncation.
Reported-by: Zeal Robot <zealci@zte.com.cn>
Signed-off-by: Changcheng Deng <deng.changcheng@zte.com.cn>
---
drivers/watchdog/davinci_wdt.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/drivers/watchdog/davinci_wdt.c b/drivers/watchdog/davinci_wdt.c
index e6eaba6bae5b..584a56893b81 100644
--- a/drivers/watchdog/davinci_wdt.c
+++ b/drivers/watchdog/davinci_wdt.c
@@ -134,7 +134,7 @@ static unsigned int davinci_wdt_get_timeleft(struct watchdog_device *wdd)
timer_counter = ioread32(davinci_wdt->base + TIM12);
timer_counter |= ((u64)ioread32(davinci_wdt->base + TIM34) << 32);
- do_div(timer_counter, freq);
+ timer_counter = div64_ul(timer_counter, freq);
return wdd->timeout - timer_counter;
}
--
2.25.1
^ permalink raw reply related [flat|nested] 2+ messages in thread
* Re: [PATCH] watchdog: davinci: Use div64_ul instead of do_div
2021-11-25 1:49 [PATCH] watchdog: davinci: Use div64_ul instead of do_div cgel.zte
@ 2021-11-25 2:33 ` Guenter Roeck
0 siblings, 0 replies; 2+ messages in thread
From: Guenter Roeck @ 2021-11-25 2:33 UTC (permalink / raw)
To: cgel.zte; +Cc: wim, linux-watchdog, linux-kernel, Changcheng Deng, Zeal Robot
On Thu, Nov 25, 2021 at 01:49:24AM +0000, cgel.zte@gmail.com wrote:
> From: Changcheng Deng <deng.changcheng@zte.com.cn>
>
> do_div() does a 64-by-32 division. Here the divisor is an unsigned long
> which on some platforms is 64 bit wide. So use div64_ul instead of do_div
> to avoid a possible truncation.
>
> Reported-by: Zeal Robot <zealci@zte.com.cn>
> Signed-off-by: Changcheng Deng <deng.changcheng@zte.com.cn>
Reviewed-by: Guenter Roeck <linux@roeck-us.net>
> ---
> drivers/watchdog/davinci_wdt.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/drivers/watchdog/davinci_wdt.c b/drivers/watchdog/davinci_wdt.c
> index e6eaba6bae5b..584a56893b81 100644
> --- a/drivers/watchdog/davinci_wdt.c
> +++ b/drivers/watchdog/davinci_wdt.c
> @@ -134,7 +134,7 @@ static unsigned int davinci_wdt_get_timeleft(struct watchdog_device *wdd)
> timer_counter = ioread32(davinci_wdt->base + TIM12);
> timer_counter |= ((u64)ioread32(davinci_wdt->base + TIM34) << 32);
>
> - do_div(timer_counter, freq);
> + timer_counter = div64_ul(timer_counter, freq);
>
> return wdd->timeout - timer_counter;
> }
> --
> 2.25.1
>
^ permalink raw reply [flat|nested] 2+ messages in thread
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2021-11-25 1:49 [PATCH] watchdog: davinci: Use div64_ul instead of do_div cgel.zte
2021-11-25 2:33 ` Guenter Roeck
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