Re: [PATCH 1/2] clocksource/drivers/timer-tegra186: Avoid 64-bit divide operation

[Daniel Lezcano <daniel.lezcano@linaro.org>]

On Sat, Jun 14, 2025 at 10:55:55AM -0700, Guenter Roeck wrote:
> Building the driver on xtensa fails with
> 
> tensa-linux-ld: drivers/clocksource/timer-tegra186.o:
> 	in function `tegra186_timer_remove':
> timer-tegra186.c:(.text+0x350):
> 	undefined reference to `__udivdi3'
> 
> Avoid the problem by rearranging the offending code to avoid the 64-bit
> divide operation.
> 

Hi Guenter,

Arnd posted a version which seems more complete.

https://lore.kernel.org/all/20250620111939.3395525-1-arnd@kernel.org/

> Fixes: 28c842c8b0f5 ("clocksource/drivers/timer-tegra186: Add WDIOC_GETTIMELEFT support")
> Cc: Pohsun Su <pohsuns@nvidia.com>
> Cc: Robert Lin <robelin@nvidia.com>
> Signed-off-by: Guenter Roeck <linux@roeck-us.net>
> ---
>  drivers/clocksource/timer-tegra186.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/drivers/clocksource/timer-tegra186.c b/drivers/clocksource/timer-tegra186.c
> index e5394f98a02e..7b506de65438 100644
> --- a/drivers/clocksource/timer-tegra186.c
> +++ b/drivers/clocksource/timer-tegra186.c
> @@ -267,7 +267,7 @@ static unsigned int tegra186_wdt_get_timeleft(struct watchdog_device *wdd)
>  	 * counter value to the time of the counter expirations that
>  	 * remain.
>  	 */
> -	timeleft += (((u64)wdt->base.timeout * USEC_PER_SEC) / 5) * (4 - expiration);
> +	timeleft += ((u64)wdt->base.timeout * (USEC_PER_SEC / 5)) * (4 - expiration);
>  
>  	/*
>  	 * Convert the current counter value to seconds,
> -- 
> 2.45.2
> 

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