[PATCH v2 3/3] timer: riscv_aclint_timer: add timer_get_boot_us for BOOTSTAGE

[Leo Liang]

Hi Chanho,

On Mon, Aug 28, 2023 at 06:49:38PM +0900, Chanho Park wrote:
> timer_get_boot_us function is required to record the boot stages as
> us-based timestamp.
> 
> Signed-off-by: Chanho Park <chanho61.park at samsung.com>
> ---
>  drivers/timer/riscv_aclint_timer.c | 22 ++++++++++++++++++++++
>  1 file changed, 22 insertions(+)
> 
> diff --git a/drivers/timer/riscv_aclint_timer.c b/drivers/timer/riscv_aclint_timer.c
> index e29d527c8d77..8b67745bb4a2 100644
> --- a/drivers/timer/riscv_aclint_timer.c
> +++ b/drivers/timer/riscv_aclint_timer.c
> @@ -6,6 +6,7 @@
>  
>  #include <common.h>
>  #include <clk.h>
> +#include <div64.h>
>  #include <dm.h>
>  #include <timer.h>
>  #include <asm/io.h>
> @@ -44,6 +45,27 @@ u64 notrace timer_early_get_count(void)
>  }
>  #endif
>  
> +#if CONFIG_IS_ENABLED(RISCV_MMODE) && CONFIG_IS_ENABLED(BOOTSTAGE)
> +ulong timer_get_boot_us(void)
> +{
> +	int ret;
> +	u64 ticks = 0;
> +	u32 rate;
> +
> +	ret = dm_timer_init();
> +	if (!ret) {
> +		rate = timer_get_rate(gd->timer);
> +		timer_get_count(gd->timer, &ticks);
> +	} else {
> +		rate = RISCV_MMODE_TIMER_FREQ;
> +		ticks = readq((void __iomem *)MTIME_REG(RISCV_MMODE_TIMERBASE,
> +							RISCV_MMODE_TIMEROFF));
> +	}
> +
> +	return lldiv(ticks * 1001, (rate / 1000));

Why is this dividend 1001 ?

Best regards,
Leo

> +}
> +#endif
> +
>  static const struct timer_ops riscv_aclint_timer_ops = {
>  	.get_count = riscv_aclint_timer_get_count,
>  };
> -- 
> 2.39.2
>