[PATCH v2 5/8] timer: Allow delays with a 32-bit microsecond timer
Bin Meng
bmeng.cn at gmail.com
Tue Jul 7 09:09:10 CEST 2020
Hi Simon,
On Sat, Jul 4, 2020 at 12:38 AM Simon Glass <sjg at chromium.org> wrote:
>
> The current get_timer_us() uses 64-bit arithmetic. When implementing
> microsecond-level timeouts, 32-bits is plenty. Add a new function to
> support this.
>
> Signed-off-by: Simon Glass <sjg at chromium.org>
> ---
>
> (no changes since v1)
>
> include/time.h | 11 +++++++++++
> lib/time.c | 5 +++++
> 2 files changed, 16 insertions(+)
>
> diff --git a/include/time.h b/include/time.h
> index e99f9c8012..434e63b075 100644
> --- a/include/time.h
> +++ b/include/time.h
> @@ -17,6 +17,17 @@ unsigned long get_timer(unsigned long base);
> unsigned long timer_get_us(void);
> uint64_t get_timer_us(uint64_t base);
>
> +/**
> + * get_timer_us_long() - Get the number of elapsed microseconds
> + *
> + * This uses 32-bit arithmetic on 32-bit machines, which is enough to handle
> + * delays of over an hour.
> + *
> + *@base: Base time to consider
> + *@return elapsed time since @base
> + */
> +unsigned long get_timer_us_long(unsigned long base);
The function name does not clear indicates this is 32-bit value
because unsigned long is still 64-bit when building for 64-bit U-Boot.
> +
> /*
> * timer_test_add_offset()
> *
> diff --git a/lib/time.c b/lib/time.c
> index 65db0f6cda..47f8c84327 100644
> --- a/lib/time.c
> +++ b/lib/time.c
> @@ -152,6 +152,11 @@ uint64_t __weak get_timer_us(uint64_t base)
> return tick_to_time_us(get_ticks()) - base;
> }
>
> +unsigned long __weak get_timer_us_long(unsigned long base)
> +{
> + return timer_get_us() - base;
> +}
> +
> unsigned long __weak notrace timer_get_us(void)
> {
> return tick_to_time(get_ticks() * 1000);
> --
Regards,
Bin
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