Re: [PATCH 1/4] watchdog: rzg2l_wdt: Fix 32bit overflow issue

[Guenter Roeck <linux@xxxxxxxxxxxx>]

On 12/11/21 1:26 PM, Biju Das wrote:
> The value of timer_cycle_us can be 0 due to 32bit overflow.
> For eg:- If we assign the counter value "0xfff" for computing
> maxval.
>
> This patch fixes this issue by appending ULL to 1024, so that
> it is promoted to 64bit.
>
> Signed-off-by: Biju Das <biju.das.jz@xxxxxxxxxxxxxx>

Reviewed-by: Guenter Roeck <linux@xxxxxxxxxxxx>

> ---
>   drivers/watchdog/rzg2l_wdt.c | 2 +-
>   1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/drivers/watchdog/rzg2l_wdt.c b/drivers/watchdog/rzg2l_wdt.c
> index 6b426df34fd6..96f2a018ab62 100644
> --- a/drivers/watchdog/rzg2l_wdt.c
> +++ b/drivers/watchdog/rzg2l_wdt.c
> @@ -53,7 +53,7 @@ static void rzg2l_wdt_wait_delay(struct rzg2l_wdt_priv *priv)
>   
>   static u32 rzg2l_wdt_get_cycle_usec(unsigned long cycle, u32 wdttime)
>   {
> -	u64 timer_cycle_us = 1024 * 1024 * (wdttime + 1) * MICRO;
> +	u64 timer_cycle_us = 1024 * 1024ULL * (wdttime + 1) * MICRO;
>   
>   	return div64_ul(timer_cycle_us, cycle);
>   }