hotplug.c
1.64 KB
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/*
* SMP support for R-Mobile / SH-Mobile
*
* Copyright (C) 2010 Magnus Damm
*
* Based on realview, 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/cpumask.h>
#include <linux/delay.h>
#include <mach/common.h>
#include <asm/cacheflush.h>
static cpumask_t dead_cpus;
int platform_cpu_kill(unsigned int cpu)
{
int k;
/* this function is running on another CPU than the offline target,
* here we need wait for shutdown code in platform_cpu_die() to
* finish before asking SoC-specific code to power off the CPU core.
*/
for (k = 0; k < 1000; k++) {
if (cpumask_test_cpu(cpu, &dead_cpus))
return shmobile_platform_cpu_kill(cpu);
mdelay(1);
}
return 0;
}
void platform_cpu_die(unsigned int cpu)
{
/* hardware shutdown code running on the CPU that is being offlined */
flush_cache_all();
dsb();
/* notify platform_cpu_kill() that hardware shutdown is finished */
cpumask_set_cpu(cpu, &dead_cpus);
/* wait for SoC code in platform_cpu_kill() to shut off CPU core
* power. CPU bring up starts from the reset vector.
*/
while (1) {
/*
* here's the WFI
*/
asm(".word 0xe320f003\n"
:
:
: "memory", "cc");
}
}
int platform_cpu_disable(unsigned int cpu)
{
cpumask_clear_cpu(cpu, &dead_cpus);
/*
* we don't allow CPU 0 to be shutdown (it is still too special
* e.g. clock tick interrupts)
*/
return cpu == 0 ? -EPERM : 0;
}