On wto, 2014-05-13 at 16:12 +0200, 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@xxxxxxxxxxx>
I am humbly reminding myself - any comments on this patch?
Best regards,
Krzysztof
> ---
> 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()) {
> + 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) {
> + if (soc_is_exynos4212()) {
> + unsigned int tmp;
> +
> + /*
> + * Exynos 4212 requires setting
> + * USE_DELAYED_RESET_ASSERTION so the CPU idle
> + * clock down feature could properly detect
> + * global idle state when CPU1 is off.
> + */
> + tmp = __raw_readl(S5P_ARM_CORE1_OPTION);
> + tmp |= S5P_USE_DELAYED_RESET_ASSERTION;
> + __raw_writel(tmp, S5P_ARM_CORE1_OPTION);
> + }
> __raw_writel(0, S5P_ARM_CORE1_CONFIGURATION);
> + }
>
> /*
> * here's the WFI
> @@ -152,7 +174,7 @@ void __ref exynos_cpu_die(unsigned int cpu)
> * bring this CPU back into the world of cache
> * coherency, and then restore interrupts
> */
> - cpu_leave_lowpower();
> + cpu_leave_lowpower(cpu);
>
> if (spurious)
> pr_warn("CPU%u: %u spurious wakeup calls\n", cpu, spurious);
> diff --git a/arch/arm/mach-exynos/regs-pmu.h b/arch/arm/mach-exynos/regs-pmu.h
> index 4f6a2560d022..1a3da4ef0e22 100644
> --- a/arch/arm/mach-exynos/regs-pmu.h
> +++ b/arch/arm/mach-exynos/regs-pmu.h
> @@ -25,6 +25,7 @@
>
> #define S5P_USE_STANDBY_WFI0 (1 << 16)
> #define S5P_USE_STANDBY_WFE0 (1 << 24)
> +#define S5P_USE_DELAYED_RESET_ASSERTION BIT(12)
>
> #define EXYNOS_SWRESET S5P_PMUREG(0x0400)
> #define EXYNOS5440_SWRESET S5P_PMUREG(0x00C4)
> @@ -107,6 +108,7 @@
>
> #define S5P_ARM_CORE1_CONFIGURATION S5P_PMUREG(0x2080)
> #define S5P_ARM_CORE1_STATUS S5P_PMUREG(0x2084)
> +#define S5P_ARM_CORE1_OPTION S5P_PMUREG(0x2088)
>
> #define S5P_PAD_RET_MAUDIO_OPTION S5P_PMUREG(0x3028)
> #define S5P_PAD_RET_GPIO_OPTION S5P_PMUREG(0x3108)
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