1/*
 2 * OpenRISC idle.c
 3 *
 4 * Linux architectural port borrowing liberally from similar works of
 5 * others.  All original copyrights apply as per the original source
 6 * declaration.
 7 *
 8 * Modifications for the OpenRISC architecture:
 9 * Copyright (C) 2003 Matjaz Breskvar <phoenix@bsemi.com>
10 * Copyright (C) 2010-2011 Jonas Bonn <jonas@southpole.se>
11 *
12 *      This program is free software; you can redistribute it and/or
13 *      modify it under the terms of the GNU General Public License
14 *      as published by the Free Software Foundation; either version
15 *      2 of the License, or (at your option) any later version.
16 *
17 * Idle daemon for or32.  Idle daemon will handle any action
18 * that needs to be taken when the system becomes idle.
19 */
20
21#include <linux/errno.h>
22#include <linux/sched.h>
23#include <linux/kernel.h>
24#include <linux/mm.h>
25#include <linux/smp.h>
26#include <linux/stddef.h>
27#include <linux/unistd.h>
28#include <linux/ptrace.h>
29#include <linux/slab.h>
30#include <linux/tick.h>
31
32#include <asm/pgtable.h>
33#include <asm/uaccess.h>
34#include <asm/system.h>
35#include <asm/io.h>
36#include <asm/processor.h>
37#include <asm/mmu.h>
38#include <asm/cache.h>
39#include <asm/pgalloc.h>
40
41void (*powersave) (void) = NULL;
42
43static inline void pm_idle(void)
44{
45	barrier();
46}
47
48void cpu_idle(void)
49{
50	set_thread_flag(TIF_POLLING_NRFLAG);
51
52	/* endless idle loop with no priority at all */
53	while (1) {
54		tick_nohz_stop_sched_tick(1);
55
56		while (!need_resched()) {
57			check_pgt_cache();
58			rmb();
59
60			clear_thread_flag(TIF_POLLING_NRFLAG);
61
62			local_irq_disable();
63			/* Don't trace irqs off for idle */
64			stop_critical_timings();
65			if (!need_resched() && powersave != NULL)
66				powersave();
67			start_critical_timings();
68			local_irq_enable();
69			set_thread_flag(TIF_POLLING_NRFLAG);
70		}
71
72		tick_nohz_restart_sched_tick();
73		preempt_enable_no_resched();
74		schedule();
75		preempt_disable();
76	}
77}