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/*
* OMAP4 SMP cpu-hotplug support
*
* Copyright (C) 2009 Texas Instruments, Inc.
* Author:
* Santosh Shilimkar <santosh.shilimkar@ti.com>
*
* Platform file needed for the OMAP4 SMP. This file is based on arm
* realview smp platform.
* Copyright (c) 2002 ARM Limited.
*
* 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>
#include <plat/io.h>
#include <plat/powerdomain.h>
static DECLARE_COMPLETION(cpu_killed);
static inline void cpu_enter_lowpower(void)
{
flush_cache_all();
/* FIXME: Code for OFF /RET */
}
static inline void cpu_leave_lowpower(void)
{
struct powerdomain *cpu1_pd;
u32 scu_pwr_st;
scu_pwr_st = omap_readl(0x48240008);
scu_pwr_st &= ~0x8;
omap_writel(scu_pwr_st, 0x48240008);
cpu1_pd = pwrdm_lookup("cpu1_pwrdm");
pwrdm_set_next_pwrst(cpu1_pd, PWRDM_POWER_ON);
}
static inline void omap_do_lowpower(unsigned int cpu)
{
u32 scu_pwr_st;
struct powerdomain *cpu1_pd;
if(omap_modify_auxcoreboot0(0x0, 0x200) != 0x0)
printk(KERN_CRIT "Secure clear status failed\n");
for (;;) {
cpu1_pd = pwrdm_lookup("cpu1_pwrdm");
pwrdm_set_next_pwrst(cpu1_pd, PWRDM_POWER_RET);
scu_pwr_st = omap_readl(0x48240008);
scu_pwr_st |= 0x8;
omap_writel(scu_pwr_st, 0x48240008);
isb();
wmb();
asm volatile("wfi\n"
:
:
: "memory", "cc");
if (omap_read_auxcoreboot0() == cpu) {
/*
* OK, proper wakeup, we're done
*/
break;
}
#ifdef DEBUG
printk("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();
omap_do_lowpower(cpu);
/*
* bring this CPU back into the world of cache
* coherency, and then restore interrupts
*/
cpu_leave_lowpower();
}
int mach_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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