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clocksource/drivers/exynos_mct: Support frc-shared property

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When the FRC is shared with another main processor, the other processor
is assumed to have started it and this processor should not write to the
global registers.

Reviewed-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
Signed-off-by: Vincent Whitchurch <vincent.whitchurch@axis.com>
Link: https://lore.kernel.org/r/20220609112738.359385-3-vincent.whitchurch@axis.com
Signed-off-by: Daniel Lezcano <daniel.lezcano@linaro.org>
This commit is contained in:
Vincent Whitchurch 2022-06-09 13:27:36 +02:00 committed by Daniel Lezcano
parent 99b701fd27
commit e8550f0e7b
1 changed files with 18 additions and 3 deletions
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21
drivers/clocksource/exynos_mct.c
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@ -233,9 +233,16 @@ static cycles_t exynos4_read_current_timer(void)
}
#endif
static int __init exynos4_clocksource_init(void)
static int __init exynos4_clocksource_init(bool frc_shared)
{
exynos4_mct_frc_start();
/*
* When the frc is shared, the main processer should have already
* turned it on and we shouldn't be writing to TCON.
*/
if (frc_shared)
mct_frc.resume = NULL;
else
exynos4_mct_frc_start();
#if defined(CONFIG_ARM)
exynos4_delay_timer.read_current_timer = &exynos4_read_current_timer;
@ -605,6 +612,7 @@ out_irq:
static int __init mct_init_dt(struct device_node *np, unsigned int int_type)
{
bool frc_shared = of_property_read_bool(np, "samsung,frc-shared");
int ret;
ret = exynos4_timer_resources(np);
@ -615,10 +623,17 @@ static int __init mct_init_dt(struct device_node *np, unsigned int int_type)
if (ret)
return ret;
ret = exynos4_clocksource_init();
ret = exynos4_clocksource_init(frc_shared);
if (ret)
return ret;
/*
* When the FRC is shared with a main processor, this secondary
* processor cannot use the global comparator.
*/
if (frc_shared)
return ret;
return exynos4_clockevent_init();
}