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From:   Peng Fan <peng.fan@nxp.com>
To:     "Peng Fan (OSS)" <peng.fan@oss.nxp.com>,
        "daniel.lezcano@linaro.org" <daniel.lezcano@linaro.org>,
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Subject: RE: [PATCH] clocksource/drivers/imx-tpm: exclude sched clock for
 ARM64
Thread-Topic: [PATCH] clocksource/drivers/imx-tpm: exclude sched clock for
 ARM64
Thread-Index: AQHYAjHm/PobCbmizE2dQK99zJo4HqyWXUQQ
Date:   Wed, 16 Feb 2022 12:29:24 +0000
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References: <20220105124304.3567629-1-peng.fan@oss.nxp.com>
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> Subject: [PATCH] clocksource/drivers/imx-tpm: exclude sched clock for
> ARM64

Gentle ping..

Thanks,
Peng.

>=20
> From: Peng Fan <peng.fan@nxp.com>
>=20
> 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 platfor=
m.
>=20
> Signed-off-by: Peng Fan <peng.fan@nxp.com>
> ---
>  drivers/clocksource/timer-imx-tpm.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
>=20
> 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 =3D &tpm_read_current_timer;
>  	tpm_delay_timer.freq =3D timer_of_rate(&to_tpm) >> 3;
>  	register_current_timer_delay(&tpm_delay_timer);
> -#endif
>=20
>  	sched_clock_register(tpm_read_sched_clock, counter_width,
>  			     timer_of_rate(&to_tpm) >> 3);
> +#endif
>=20
>  	return clocksource_mmio_init(timer_base + TPM_CNT,
>  				     "imx-tpm",
> --
> 2.25.1