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Commit 292ec42a authored by Russell King's avatar Russell King
Browse files

ARM: pm: add function to set WFI low-power mode for SMP CPUs 



Add a function to set the SCU low-power mode for SMP CPUs.  This
centralizes this functionality rather than having to expose the
SCU register definitions to each platform.

Signed-off-by: default avatarRussell King <rmk+kernel@arm.linux.org.uk>
parent afe8a887

arch/arm/include/asm/smp_scu.h

+7 −0
Original line number Diff line number Diff line 
#ifndef __ASMARM_ARCH_SCU_H

#define __ASMARM_ARCH_SCU_H



#define SCU_PM_NORMAL	0

#define SCU_PM_DORMANT	2

#define SCU_PM_POWEROFF	3



#ifndef __ASSEMBLER__

unsigned int scu_get_core_count(void __iomem *);

void scu_enable(void __iomem *);

int scu_power_mode(void __iomem *, unsigned int);

#endif



#endif

arch/arm/kernel/smp_scu.c

+23 −0
Original line number Diff line number Diff line
@@ -50,3 +50,26 @@ void __init scu_enable(void __iomem *scu_base) 
	 */

	flush_cache_all();

}



/*

 * Set the executing CPUs power mode as defined.  This will be in

 * preparation for it executing a WFI instruction.

 *

 * This function must be called with preemption disabled, and as it

 * has the side effect of disabling coherency, caches must have been

 * flushed.  Interrupts must also have been disabled.

 */

int scu_power_mode(void __iomem *scu_base, unsigned int mode)

{

	unsigned int val;

	int cpu = smp_processor_id();



	if (mode > 3 || mode == 1 || cpu > 3)

		return -EINVAL;



	val = __raw_readb(scu_base + SCU_CPU_STATUS + cpu) & ~0x03;

	val |= mode;

	__raw_writeb(val, scu_base + SCU_CPU_STATUS + cpu);



	return 0;

}