OpenRISC: Idle/Power management

/*

 * OpenRISC idle.c

 *

 * Linux architectural port borrowing liberally from similar works of

 * others.  All original copyrights apply as per the original source

 * declaration.

 *

 * Modifications for the OpenRISC architecture:

 * Copyright (C) 2003 Matjaz Breskvar <phoenix@bsemi.com>

 * Copyright (C) 2010-2011 Jonas Bonn <jonas@southpole.se>

 *

 *      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.

 *

 * Idle daemon for or32.  Idle daemon will handle any action

 * that needs to be taken when the system becomes idle.

 */

#include <linux/errno.h>

#include <linux/sched.h>

#include <linux/kernel.h>

#include <linux/mm.h>

#include <linux/smp.h>

#include <linux/stddef.h>

#include <linux/unistd.h>

#include <linux/ptrace.h>

#include <linux/slab.h>

#include <linux/tick.h>

#include <asm/pgtable.h>

#include <asm/uaccess.h>

#include <asm/system.h>

#include <asm/io.h>

#include <asm/processor.h>

#include <asm/mmu.h>

#include <asm/cache.h>

#include <asm/pgalloc.h>

void (*powersave) (void) = NULL;

static inline void pm_idle(void)

{

	barrier();

}

void cpu_idle(void)

{

	set_thread_flag(TIF_POLLING_NRFLAG);

	/* endless idle loop with no priority at all */

	while (1) {

		tick_nohz_stop_sched_tick(1);

		while (!need_resched()) {

			check_pgt_cache();

			rmb();

			clear_thread_flag(TIF_POLLING_NRFLAG);

			local_irq_disable();

			/* Don't trace irqs off for idle */

			stop_critical_timings();

			if (!need_resched() && powersave != NULL)

				powersave();

			start_critical_timings();

			local_irq_enable();

			set_thread_flag(TIF_POLLING_NRFLAG);

		}

		tick_nohz_restart_sched_tick();

		preempt_enable_no_resched();

		schedule();

		preempt_disable();

	}

}