/* * Copyright (C) 2014 Imagination Technologies Ltd. * * This program is free software; you can redistribute it and/or modify it * under the terms of the GNU General Public License as published by the * Free Software Foundation; either version 2 of the License, or (at your * option) any later version. * * 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(); } /** * 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);