[PATCH v1 2/4] clocksource: arm_architected_timer: support clock-frequency

[Ahmad Fatoum]

On 7/29/25 22:36, Ivaylo Ivanov wrote:
> Some platforms, like the Samsung Galaxy S8, leave CNTFRQ_EL0 unset in
> the previous stage bootloader. Therefore reading it causes a hang and
> the boot proccess is halted.
> 
> Since on such retail devices there is no way to set it without replacing
> the entire boot chain, allow setting a value from clock-frequency
> whenever it's passed.
> 
> Signed-off-by: Ivaylo Ivanov <ivo.ivanov.ivanov1 at gmail.com>

Reviewed-by: Ahmad Fatoum <a.fatoum at pengutronix.de>

Linux does this too, so I think regressions are unlikely.

Cheers,
Ahmad

> ---
>  drivers/clocksource/arm_architected_timer.c | 11 ++++++++++-
>  1 file changed, 10 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/clocksource/arm_architected_timer.c b/drivers/clocksource/arm_architected_timer.c
> index 9a1f2d2b..daced94c 100644
> --- a/drivers/clocksource/arm_architected_timer.c
> +++ b/drivers/clocksource/arm_architected_timer.c
> @@ -24,7 +24,16 @@ static struct clocksource cs = {
>  
>  static int arm_arch_timer_probe(struct device *dev)
>  {
> -	cs.mult = clocksource_hz2mult(get_cntfrq(), cs.shift);
> +	u32 cntfrq;
> +	int ret;
> +
> +	/* Some platforms don't set CNTFRQ_EL0 before barebox */
> +	ret = of_property_read_u32(dev->of_node, "clock-frequency", &cntfrq);
> +
> +	if (ret)
> +		cntfrq = get_cntfrq();
> +
> +	cs.mult = clocksource_hz2mult(cntfrq, cs.shift);
>  
>  	return init_clock(&cs);
>  }

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