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// SPDX-License-Identifier: GPL-2.0-or-later
/*
* Copyright (C) 2014 Imagination Technologies Ltd.
*
* CPU PM notifiers for saving/restoring general CPU state.
*/
#include <linux/cpu_pm.h>
#include <linux/init.h>
#include <asm/dsp.h>
#include <asm/fpu.h>
#include <asm/mmu_context.h>
#include <asm/pm.h>
#include <asm/watch.h>
/* Used by PM helper macros in asm/pm.h */
struct mips_static_suspend_state mips_static_suspend_state;
/**
* mips_cpu_save() - Save general CPU state.
* Ensures that general CPU context is saved, notably FPU and DSP.
*/
static int mips_cpu_save(void)
{
/* Save FPU state */
lose_fpu(1);
/* Save DSP state */
save_dsp(current);
return 0;
}
/**
* mips_cpu_restore() - Restore general CPU state.
* Restores important CPU context.
*/
static void mips_cpu_restore(void)
{
unsigned int cpu = smp_processor_id();
/* Restore ASID */
if (current->mm)
write_c0_entryhi(cpu_asid(cpu, current->mm));
/* Restore DSP state */
restore_dsp(current);
/* Restore UserLocal */
if (cpu_has_userlocal)
write_c0_userlocal(current_thread_info()->tp_value);
/* Restore watch registers */
__restore_watch(current);
}
/**
* mips_pm_notifier() - Notifier for preserving general CPU context.
* @self: Notifier block.
* @cmd: CPU PM event.
* @v: Private data (unused).
*
* This is called when a CPU power management event occurs, and is used to
* ensure that important CPU context is preserved across a CPU power down.
*/
static int mips_pm_notifier(struct notifier_block *self, unsigned long cmd,
void *v)
{
int ret;
switch (cmd) {
case CPU_PM_ENTER:
ret = mips_cpu_save();
if (ret)
return NOTIFY_STOP;
break;
case CPU_PM_ENTER_FAILED:
case CPU_PM_EXIT:
mips_cpu_restore();
break;
}
return NOTIFY_OK;
}
static struct notifier_block mips_pm_notifier_block = {
.notifier_call = mips_pm_notifier,
};
static int __init mips_pm_init(void)
{
return cpu_pm_register_notifier(&mips_pm_notifier_block);
}
arch_initcall(mips_pm_init);
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