RE: [PATCH] clocksource/drivers/imx-tpm: exclude sched clock for ARM64

From: Peng Fan
Date: Wed Feb 16 2022 - 07:29:32 EST


> Subject: [PATCH] clocksource/drivers/imx-tpm: exclude sched clock for
> ARM64

Gentle ping..

Thanks,
Peng.

>
> From: Peng Fan <peng.fan@xxxxxxx>
>
> For ARM64 platform such as i.MX8ULP which has ARMv8 generic timer as
> sched clock, which is much faster compared with tpm sched clock. Reading
> the tpm count register in i.MX8ULP requires about 290ns, this is slow and
> introduce scheduler latency. So exclude tpm sched clock for ARM64 platform.
>
> Signed-off-by: Peng Fan <peng.fan@xxxxxxx>
> ---
> drivers/clocksource/timer-imx-tpm.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/drivers/clocksource/timer-imx-tpm.c
> b/drivers/clocksource/timer-imx-tpm.c
> index 2cdc077a39f5..2bd530b9adc4 100644
> --- a/drivers/clocksource/timer-imx-tpm.c
> +++ b/drivers/clocksource/timer-imx-tpm.c
> @@ -150,10 +150,10 @@ static int __init tpm_clocksource_init(void)
> tpm_delay_timer.read_current_timer = &tpm_read_current_timer;
> tpm_delay_timer.freq = timer_of_rate(&to_tpm) >> 3;
> register_current_timer_delay(&tpm_delay_timer);
> -#endif
>
> sched_clock_register(tpm_read_sched_clock, counter_width,
> timer_of_rate(&to_tpm) >> 3);
> +#endif
>
> return clocksource_mmio_init(timer_base + TPM_CNT,
> "imx-tpm",
> --
> 2.25.1