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Commit c7b0aff4 authored by Kevin Hilman's avatar Kevin Hilman Committed by Russell King
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ARM: 6428/1: add cpu_idle_wait() to support CPUidle on SMP systems. 



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.

Tested-by: default avatarColin Cross <ccross@android.com>
Signed-off-by: default avatarKevin Hilman <khilman@deeprootsystems.com>
Signed-off-by: default avatarRussell King <rmk+kernel@arm.linux.org.uk>
parent 7511db9d

arch/arm/Kconfig

+3 −0
Original line number Diff line number Diff line
@@ -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

arch/arm/include/asm/system.h

+2 −0
Original line number Diff line number Diff line
@@ -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

arch/arm/kernel/process.c

+19 −0
Original line number Diff line number Diff line
@@ -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