Commit 771dae81 authored by Deepthi Dharwar's avatar Deepthi Dharwar Committed by Benjamin Herrenschmidt
Browse files

powerpc/cpuidle: Add cpu_idle_wait() to allow switching of idle routines 



This patch provides cpu_idle_wait() routine for the powerpc
platform which is required by the cpuidle subsystem. This
routine is required to change the idle handler on SMP systems.
The equivalent routine for x86 is in arch/x86/kernel/process.c
but the powerpc implementation is different.

cpuidle_disable variable is to enable/disable cpuidle
framework if power_save option is set during the boot
time.

Signed-off-by: default avatarDeepthi Dharwar <deepthi@linux.vnet.ibm.com>
Signed-off-by: default avatarTrinabh Gupta <g.trinabh@gmail.com>
Signed-off-by: default avatarArun R Bharadwaj <arun.r.bharadwaj@gmail.com>
Signed-off-by: default avatarBenjamin Herrenschmidt <benh@kernel.crashing.org>
parent faa8bf88

arch/powerpc/Kconfig

+4 −0
Original line number Diff line number Diff line
@@ -87,6 +87,10 @@ config ARCH_HAS_ILOG2_U64 
	bool

	default y if 64BIT



config ARCH_HAS_CPU_IDLE_WAIT

	bool

	default y



config GENERIC_HWEIGHT

	bool

	default y

arch/powerpc/include/asm/processor.h

+2 −0
Original line number Diff line number Diff line
@@ -382,6 +382,8 @@ static inline unsigned long get_clean_sp(struct pt_regs *regs, int is_32) 
}

#endif



enum idle_boot_override {IDLE_NO_OVERRIDE = 0, IDLE_POWERSAVE_OFF};



#endif /* __KERNEL__ */

#endif /* __ASSEMBLY__ */

#endif /* _ASM_POWERPC_PROCESSOR_H */

arch/powerpc/include/asm/system.h

+1 −0
Original line number Diff line number Diff line
@@ -221,6 +221,7 @@ extern unsigned long klimit; 
extern void *zalloc_maybe_bootmem(size_t size, gfp_t mask);



extern int powersave_nap;	/* set if nap mode can be used in idle loop */

void cpu_idle_wait(void);



/*

 * Atomic exchange

arch/powerpc/kernel/idle.c

+27 −0
Original line number Diff line number Diff line
@@ -39,9 +39,13 @@ 
#define cpu_should_die()	0

#endif



unsigned long cpuidle_disable = IDLE_NO_OVERRIDE;

EXPORT_SYMBOL(cpuidle_disable);



static int __init powersave_off(char *arg)

{

	ppc_md.power_save = NULL;

	cpuidle_disable = IDLE_POWERSAVE_OFF;

	return 0;

}

__setup("powersave=off", powersave_off);
@@ -102,6 +106,29 @@ void cpu_idle(void) 
	}

}





/*

 * cpu_idle_wait - Used to ensure that all the CPUs come out of the old

 * idle loop and start using the new idle loop.

 * Required while changing idle handler on SMP systems.

 * Caller must have changed idle handler to the new value before the call.

 * This window may be larger on shared systems.

 */

void cpu_idle_wait(void)

{

	int cpu;

	smp_mb();



	/* kick all the CPUs so that they exit out of old idle routine */

	get_online_cpus();

	for_each_online_cpu(cpu) {

		if (cpu != smp_processor_id())

			smp_send_reschedule(cpu);

	}

	put_online_cpus();

}

EXPORT_SYMBOL_GPL(cpu_idle_wait);



int powersave_nap;



#ifdef CONFIG_SYSCTL

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