Russell,
Kevin Hilman <khilman@xxxxxxxxxxxxxxxxxxx> writes:
> In order for CPUidle to work on SMP systems, an implementation of
> cpu_idle_wait() is needed.
>
> This patch duplicates the x86 implementation of cpu_idle_wait() for
> ARM.
>
> Signed-off-by: Kevin Hilman <khilman@xxxxxxxxxxxxxxxxxxx>
Are you OK with this for the patch system for 2.6.37?
Kevin
> ---
> arch/arm/Kconfig | 3 +++
> arch/arm/include/asm/system.h | 2 ++
> arch/arm/kernel/process.c | 19 +++++++++++++++++++
> 3 files changed, 24 insertions(+), 0 deletions(-)
>
> diff --git a/arch/arm/Kconfig b/arch/arm/Kconfig
> index 553b7cf..10ce6dc 100644
> --- a/arch/arm/Kconfig
> +++ b/arch/arm/Kconfig
> @@ -145,6 +145,9 @@ config ARCH_HAS_CPUFREQ
> and that the relevant menu configurations are displayed for
> it.
>
> +config ARCH_HAS_CPU_IDLE_WAIT
> + def_bool y
> +
> config GENERIC_HWEIGHT
> bool
> default y
> diff --git a/arch/arm/include/asm/system.h b/arch/arm/include/asm/system.h
> index 8ba1ccf..48e360c 100644
> --- a/arch/arm/include/asm/system.h
> +++ b/arch/arm/include/asm/system.h
> @@ -325,6 +325,8 @@ static inline unsigned long __xchg(unsigned long x, volatile void *ptr, int size
> extern void disable_hlt(void);
> extern void enable_hlt(void);
>
> +void cpu_idle_wait(void);
> +
> #include <asm-generic/cmpxchg-local.h>
>
> #if __LINUX_ARM_ARCH__ < 6
> diff --git a/arch/arm/kernel/process.c b/arch/arm/kernel/process.c
> index 401e38b..23def52 100644
> --- a/arch/arm/kernel/process.c
> +++ b/arch/arm/kernel/process.c
> @@ -135,6 +135,25 @@ EXPORT_SYMBOL(pm_power_off);
> void (*arm_pm_restart)(char str, const char *cmd) = arm_machine_restart;
> EXPORT_SYMBOL_GPL(arm_pm_restart);
>
> +static void do_nothing(void *unused)
> +{
> +}
> +
> +/*
> + * cpu_idle_wait - Used to ensure that all the CPUs discard old value of
> + * pm_idle and update to new pm_idle value. Required while changing pm_idle
> + * handler on SMP systems.
> + *
> + * Caller must have changed pm_idle to the new value before the call. Old
> + * pm_idle value will not be used by any CPU after the return of this function.
> + */
> +void cpu_idle_wait(void)
> +{
> + smp_mb();
> + /* kick all the CPUs so that they exit out of pm_idle */
> + smp_call_function(do_nothing, NULL, 1);
> +}
> +EXPORT_SYMBOL_GPL(cpu_idle_wait);
>
> /*
> * This is our default idle handler. We need to disable
--
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