1/*
2 * Idle daemon for PowerPC.  Idle daemon will handle any action
3 * that needs to be taken when the system becomes idle.
4 *
5 * Originally written by Cort Dougan (cort@cs.nmt.edu).
6 * Subsequent 32-bit hacking by Tom Rini, Armin Kuster,
7 * Paul Mackerras and others.
8 *
9 * iSeries supported added by Mike Corrigan <mikejc@us.ibm.com>
10 *
11 * Additional shared processor, SMT, and firmware support
12 *    Copyright (c) 2003 Dave Engebretsen <engebret@us.ibm.com>
13 *
14 * 32-bit and 64-bit versions merged by Paul Mackerras <paulus@samba.org>
15 *
16 * This program is free software; you can redistribute it and/or
17 * modify it under the terms of the GNU General Public License
18 * as published by the Free Software Foundation; either version
19 * 2 of the License, or (at your option) any later version.
20 */
21
22#include <linux/sched.h>
23#include <linux/kernel.h>
24#include <linux/smp.h>
25#include <linux/cpu.h>
26#include <linux/sysctl.h>
27#include <linux/tick.h>
28
29#include <asm/processor.h>
30#include <asm/cputable.h>
31#include <asm/time.h>
32#include <asm/machdep.h>
33#include <asm/runlatch.h>
34#include <asm/smp.h>
35
36
37unsigned long cpuidle_disable = IDLE_NO_OVERRIDE;
38EXPORT_SYMBOL(cpuidle_disable);
39
40static int __init powersave_off(char *arg)
41{
42	ppc_md.power_save = NULL;
43	cpuidle_disable = IDLE_POWERSAVE_OFF;
44	return 0;
45}
46__setup("powersave=off", powersave_off);
47
48#ifdef CONFIG_HOTPLUG_CPU
49void arch_cpu_idle_dead(void)
50{
51	sched_preempt_enable_no_resched();
52	cpu_die();
53}
54#endif
55
56void arch_cpu_idle(void)
57{
58	ppc64_runlatch_off();
59
60	if (ppc_md.power_save) {
61		ppc_md.power_save();
62		/*
63		 * Some power_save functions return with
64		 * interrupts enabled, some don't.
65		 */
66		if (irqs_disabled())
67			local_irq_enable();
68	} else {
69		local_irq_enable();
70		/*
71		 * Go into low thread priority and possibly
72		 * low power mode.
73		 */
74		HMT_low();
75		HMT_very_low();
76	}
77
78	HMT_medium();
79	ppc64_runlatch_on();
80}
81
82int powersave_nap;
83
84#ifdef CONFIG_SYSCTL
85/*
86 * Register the sysctl to set/clear powersave_nap.
87 */
88static struct ctl_table powersave_nap_ctl_table[] = {
89	{
90		.procname	= "powersave-nap",
91		.data		= &powersave_nap,
92		.maxlen		= sizeof(int),
93		.mode		= 0644,
94		.proc_handler	= proc_dointvec,
95	},
96	{}
97};
98static struct ctl_table powersave_nap_sysctl_root[] = {
99	{
100		.procname	= "kernel",
101		.mode		= 0555,
102		.child		= powersave_nap_ctl_table,
103	},
104	{}
105};
106
107static int __init
108register_powersave_nap_sysctl(void)
109{
110	register_sysctl_table(powersave_nap_sysctl_root);
111
112	return 0;
113}
114__initcall(register_powersave_nap_sysctl);
115#endif
116