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/*
* 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 <asm/cacheflush.h>
extern volatile int pen_release;
static inline void cpu_enter_lowpower(void)
{
/* Just flush the cache. Changing the coherency is not yet
* available on msm. */
flush_cache_all();
}
static inline void cpu_leave_lowpower(void)
{
}
static inline void platform_do_lowpower(unsigned int cpu)
{
/* Just enter wfi for now. TODO: Properly shut off the cpu. */
for (;;) {
/*
* here's the WFI
*/
asm("wfi"
:
:
: "memory", "cc");
if (pen_release == cpu_logical_map(cpu)) {
/*
* 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
*
* The trouble is, letting people know about this is not really
* possible, since we are currently running incoherently, and
* therefore cannot safely call printk() or anything else
*/
pr_debug("CPU%u: spurious wakeup call\n", cpu);
}
}
int platform_cpu_kill(unsigned int cpu)
{
return 1;
}
/*
* platform-specific code to shutdown a CPU
*
* Called with IRQs disabled
*/
void platform_cpu_die(unsigned int cpu)
{
/*
* we're ready for shutdown now, so do it
*/
cpu_enter_lowpower();
platform_do_lowpower(cpu);
/*
* bring this CPU back into the world of cache
* coherency, and then restore interrupts
*/
cpu_leave_lowpower();
}
int platform_cpu_disable(unsigned int cpu)
{
/*
* we don't allow CPU 0 to be shutdown (it is still too special
* e.g. clock tick interrupts)
*/
return cpu == 0 ? -EPERM : 0;
}
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