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/* linux arch/arm/mach-exynos4/hotplug.c
*
* Cloned from linux/arch/arm/mach-realview/hotplug.c
*
* Copyright (C) 2002 ARM Ltd.
* All Rights Reserved
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License version 2 as
* published by the Free Software Foundation.
*/
#include <linux/kernel.h>
#include <linux/errno.h>
#include <linux/smp.h>
#include <linux/io.h>
#include <asm/cacheflush.h>
#include <asm/cp15.h>
#include <asm/smp_plat.h>
#include "common.h"
#include "regs-pmu.h"
static inline void cpu_leave_lowpower(void)
{
unsigned int v;
asm volatile(
"mrc p15, 0, %0, c1, c0, 0\n"
" orr %0, %0, %1\n"
" mcr p15, 0, %0, c1, c0, 0\n"
" mrc p15, 0, %0, c1, c0, 1\n"
" orr %0, %0, %2\n"
" mcr p15, 0, %0, c1, c0, 1\n"
: "=&r" (v)
: "Ir" (CR_C), "Ir" (0x40)
: "cc");
}
static inline void platform_do_lowpower(unsigned int cpu, int *spurious)
{
u32 mpidr = cpu_logical_map(cpu);
u32 core_id = MPIDR_AFFINITY_LEVEL(mpidr, 0);
for (;;) {
/* Turn the CPU off on next WFI instruction. */
exynos_cpu_power_down(core_id);
wfi();
if (pen_release == core_id) {
/*
* OK, proper wakeup, we're done
*/
break;
}
/*
* Getting here, means that we have come out of WFI without
* having been woken up - this shouldn't happen
*
* Just note it happening - when we're woken, we can report
* its occurrence.
*/
(*spurious)++;
}
}
/*
* platform-specific code to shutdown a CPU
*
* Called with IRQs disabled
*/
void __ref exynos_cpu_die(unsigned int cpu)
{
int spurious = 0;
v7_exit_coherency_flush(louis);
platform_do_lowpower(cpu, &spurious);
/*
* bring this CPU back into the world of cache
* coherency, and then restore interrupts
*/
cpu_leave_lowpower();
if (spurious)
pr_warn("CPU%u: %u spurious wakeup calls\n", cpu, spurious);
}
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