[PATCH] clocksource/drivers/arm_arch_timer: export arch_timer_get_rate

[Mark Rutland]

On Tue, Jan 12, 2021 at 10:31:40AM +0900, Chanho Park wrote:
> This patch adds to export arch_timer_get_rate function for calculating
> absolute timestamp which is based on arch timer like below.
> arch_timer_read_counter was already exported but arch_timer_get_rate
> wasn't. Thus, this patch tries to export this to use this function from
> loadable kernel module.

Can you please explain /where/ this would be used? i.e. which module?

Generally we try to avoid drivers depending on the specific clocksource,
so I think there needs to be stronger rationale for exposing this.

Thanks,
Mark.

> 
> u32 rate = arch_timer_get_rate() / (1000 * 1000);
> u64 abs_ns = arch_timer_read_counter() * 1000 / rate;
> 
> Cc: Mark Rutland <mark.rutland at arm.com>
> Cc: Marc Zyngier <maz at kernel.org>
> Cc: Daniel Lezcano <daniel.lezcano at linaro.org>
> Cc: Thomas Gleixner <tglx at linutronix.de>
> Signed-off-by: Chanho Park <chanho61.park at samsung.com>
> ---
>  drivers/clocksource/arm_arch_timer.c | 1 +
>  1 file changed, 1 insertion(+)
> 
> diff --git a/drivers/clocksource/arm_arch_timer.c b/drivers/clocksource/arm_arch_timer.c
> index d0177824c518..f3f49d96dbe9 100644
> --- a/drivers/clocksource/arm_arch_timer.c
> +++ b/drivers/clocksource/arm_arch_timer.c
> @@ -961,6 +961,7 @@ u32 arch_timer_get_rate(void)
>  {
>  	return arch_timer_rate;
>  }
> +EXPORT_SYMBOL_GPL(arch_timer_get_rate);
>  
>  bool arch_timer_evtstrm_available(void)
>  {
> -- 
> 2.23.0
>