Messages in this thread |  | | Date | Fri, 30 May 2014 13:50:45 +0200 | | From | Tomasz Figa <> | | Subject | Re: [PATCH] ARM: exynos4212: hotplug: Fix CPU idle clock down after CPU1 off |
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Hi Krzysztof,
On 13.05.2014 16:12, Krzysztof Kozlowski wrote: > On Exynos4212 USE_DELAYED_RESET_ASSERTION must be set in > ARM_CORE1_OPTION register during CPU power down. This is the proper way > of powering down CPU. Additionally without this the CPU clock down won't > work after powering down CPU1 and CPU will work at full frequency chosen > by CPUfreq governor. > > Signed-off-by: Krzysztof Kozlowski <k.kozlowski@samsung.com> > --- > arch/arm/mach-exynos/hotplug.c | 28 +++++++++++++++++++++++++--- > arch/arm/mach-exynos/regs-pmu.h | 2 ++ > 2 files changed, 27 insertions(+), 3 deletions(-) > > diff --git a/arch/arm/mach-exynos/hotplug.c b/arch/arm/mach-exynos/hotplug.c > index 5eead530c6f8..59b813e74558 100644 > --- a/arch/arm/mach-exynos/hotplug.c > +++ b/arch/arm/mach-exynos/hotplug.c > @@ -74,7 +74,7 @@ static inline void cpu_enter_lowpower_a15(void) > dsb(); > } > > -static inline void cpu_leave_lowpower(void) > +static inline void cpu_leave_lowpower(unsigned int cpu) > { > unsigned int v; > > @@ -88,6 +88,14 @@ static inline void cpu_leave_lowpower(void) > : "=&r" (v) > : "Ir" (CR_C), "Ir" (0x40) > : "cc"); > + > + if (cpu == 1 && soc_is_exynos4212()) {
AFAIK this is needed not only on Exynos4x12, but at least also on 4412. Also I don't think the (cpu == 1) condition is necessary. See below.
> + unsigned int tmp; > + > + tmp = __raw_readl(S5P_ARM_CORE1_OPTION); > + tmp &= ~(S5P_USE_DELAYED_RESET_ASSERTION); > + __raw_writel(tmp, S5P_ARM_CORE1_OPTION); > + } > } > > static inline void platform_do_lowpower(unsigned int cpu, int *spurious) > @@ -95,8 +103,22 @@ static inline void platform_do_lowpower(unsigned int cpu, int *spurious) > for (;;) { > > /* make cpu1 to be turned off at next WFI command */ > - if (cpu == 1) > + if (cpu == 1) {
I think this patch should be rebased on top of my "[PATCH] ARM: EXYNOS: Fix core ID used by platsmp and hotplug code". Then instead of if (cpu == 1) you would just use EXYNOS_ARM_CORE_OPTION(core_id).
Also same comment as above, I believe this is also needed on Exynos4412.
Best regards, Tomasz
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