Re: [RESEND PATCH v3] clocksource: exynos_mct: Add the support for Exynos 64bit SoC

[Daniel Lezcano]

On 01/14/2015 04:51 PM, Kukjin Kim wrote:
> On 01/14/15 14:33, Chanwoo Choi wrote:
>
> Hi,
>
> + Doug, Olof
>
> > This patch adds the support for Exynos 64bit SoC. The delay_timer is only used
> > for Exynos 32bit SoC.
> Yes, the Exynos MCT(Multi-Core Timer) is 64bit timer and it is available
> on 64bit exynos SoC such as exynos7. But basically ARMv8 architecture is
> including ARM ARCH timer (ARM Generic Timer) and exynos7 also has
> implemented it and additionally its access is faster than using memory
> mapped register called SFR for MCT...so Doug submitted patch to use MCT
> on 32bit exynos SoCs before.
>
> I know using MCT on 64bit exynos is usefulness for Power Management and
> I need to talk to relevant guys in office again. If anything, I'll let
> you know.

I will wait for your answer before digging more the patch.

Thanks
  -- Daniel

> > Cc: Daniel Lezcano <daniel.lezcano@xxxxxxxxxx>
> > Cc: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
> > Cc: Kukjin Kim <kgene.kim@xxxxxxxxxxx>
> > Cc: Mark Rutland <mark.rutland@xxxxxxx>
> > Signed-off-by: Chanwoo Choi <cw00.choi@xxxxxxxxxxx>
> > ---
> > This patch set is tested on 64-bit Exynos SoC. I send only this patch from
> > following patchst[1].
> > [1] https://lkml.org/lkml/2014/12/2/134
> >
> > Changes from v2:
> > - None
> > Changes from v1:
> > - Use CONFIG_ARM instead of CONFIG_ARM64
> >
> >   drivers/clocksource/Kconfig      | 1 -
> >   drivers/clocksource/exynos_mct.c | 4 ++++
> >   2 files changed, 4 insertions(+), 1 deletion(-)
> >
> > diff --git a/drivers/clocksource/Kconfig b/drivers/clocksource/Kconfig
> > index fc01ec2..be38119 100644
> > --- a/drivers/clocksource/Kconfig
> > +++ b/drivers/clocksource/Kconfig
> > @@ -135,7 +135,6 @@ config CLKSRC_METAG_GENERIC
> >
> >   config CLKSRC_EXYNOS_MCT
> >   	def_bool y if ARCH_EXYNOS
> > -	depends on !ARM64
> >   	help
> >   	  Support for Multi Core Timer controller on Exynos SoCs.
> >
> > diff --git a/drivers/clocksource/exynos_mct.c b/drivers/clocksource/exynos_mct.c
> > index 9403061..b840ea1 100644
> > --- a/drivers/clocksource/exynos_mct.c
> > +++ b/drivers/clocksource/exynos_mct.c
> > @@ -223,6 +223,7 @@ static u64 notrace exynos4_read_sched_clock(void)
> >   	return exynos4_read_count_32();
> >   }
> >
> > +#if defined(CONFIG_ARM)
> >   static struct delay_timer exynos4_delay_timer;
> >
> >   static cycles_t exynos4_read_current_timer(void)
> > @@ -231,14 +232,17 @@ static cycles_t exynos4_read_current_timer(void)
> >   			 "cycles_t needs to move to 32-bit for ARM64 usage");
> >   	return exynos4_read_count_32();
> >   }
> > +#endif
> >
> >   static void __init exynos4_clocksource_init(void)
> >   {
> >   	exynos4_mct_frc_start();
> >
> > +#if defined(CONFIG_ARM)
> >   	exynos4_delay_timer.read_current_timer = &exynos4_read_current_timer;
> >   	exynos4_delay_timer.freq = clk_rate;
> >   	register_current_timer_delay(&exynos4_delay_timer);
> > +#endif
> >
> >   	if (clocksource_register_hz(&mct_frc, clk_rate))
> >   		panic("%s: can't register clocksource\n", mct_frc.name);


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