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r: 221053
b: refs/heads/master
c: 11adcc2
h: refs/heads/master
i:
  221051: 8ea5094
v: v3
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Changhwan Youn authored and Kukjin Kim committed Oct 20, 2010
1 parent 72f6f66 commit 4b4151c
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2 changes: 1 addition & 1 deletion [refs]
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---
refs/heads/master: 34d79315a22b743a8f4e26c2e11fa16469c71473
refs/heads/master: 11adcc29f068229ca77fb91b42047f1a03cf500c
144 changes: 144 additions & 0 deletions trunk/arch/arm/mach-s5pv310/hotplug.c
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/* linux arch/arm/mach-s5pv310/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/completion.h>

#include <asm/cacheflush.h>

extern volatile int pen_release;

static DECLARE_COMPLETION(cpu_killed);

static inline void cpu_enter_lowpower(void)
{
unsigned int v;

flush_cache_all();
asm volatile(
" mcr p15, 0, %1, c7, c5, 0\n"
" mcr p15, 0, %1, c7, c10, 4\n"
/*
* Turn off coherency
*/
" mrc p15, 0, %0, c1, c0, 1\n"
" bic %0, %0, #0x20\n"
" mcr p15, 0, %0, c1, c0, 1\n"
" mrc p15, 0, %0, c1, c0, 0\n"
" bic %0, %0, #0x04\n"
" mcr p15, 0, %0, c1, c0, 0\n"
: "=&r" (v)
: "r" (0)
: "cc");
}

static inline void cpu_leave_lowpower(void)
{
unsigned int v;

asm volatile(
"mrc p15, 0, %0, c1, c0, 0\n"
" orr %0, %0, #0x04\n"
" mcr p15, 0, %0, c1, c0, 0\n"
" mrc p15, 0, %0, c1, c0, 1\n"
" orr %0, %0, #0x20\n"
" mcr p15, 0, %0, c1, c0, 1\n"
: "=&r" (v)
:
: "cc");
}

static inline void platform_do_lowpower(unsigned int cpu)
{
/*
* there is no power-control hardware on this platform, so all
* we can do is put the core into WFI; this is safe as the calling
* code will have already disabled interrupts
*/
for (;;) {
/*
* here's the WFI
*/
asm(".word 0xe320f003\n"
:
:
: "memory", "cc");

if (pen_release == 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
*/
#ifdef DEBUG
printk(KERN_WARN "CPU%u: spurious wakeup call\n", cpu);
#endif
}
}

int platform_cpu_kill(unsigned int cpu)
{
return wait_for_completion_timeout(&cpu_killed, 5000);
}

/*
* platform-specific code to shutdown a CPU
*
* Called with IRQs disabled
*/
void platform_cpu_die(unsigned int cpu)
{
#ifdef DEBUG
unsigned int this_cpu = hard_smp_processor_id();

if (cpu != this_cpu) {
printk(KERN_CRIT "Eek! platform_cpu_die running on %u, should be %u\n",
this_cpu, cpu);
BUG();
}
#endif

printk(KERN_NOTICE "CPU%u: shutdown\n", cpu);
complete(&cpu_killed);

/*
* 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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