blob: 049dda60e4750296e7b890e752e6420d0d1fb769 [file] [log] [blame]
Linus Torvalds1da177e2005-04-16 15:20:36 -07001/*
2 * Idle daemon for PowerPC. Idle daemon will handle any action
3 * that needs to be taken when the system becomes idle.
4 *
Paul Mackerrasa0652fc2006-03-27 15:03:03 +11005 * Originally written by Cort Dougan (cort@cs.nmt.edu).
6 * Subsequent 32-bit hacking by Tom Rini, Armin Kuster,
7 * Paul Mackerras and others.
Linus Torvalds1da177e2005-04-16 15:20:36 -07008 *
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 *
Paul Mackerrasa0652fc2006-03-27 15:03:03 +110014 * 32-bit and 64-bit versions merged by Paul Mackerras <paulus@samba.org>
15 *
Linus Torvalds1da177e2005-04-16 15:20:36 -070016 * 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
Linus Torvalds1da177e2005-04-16 15:20:36 -070022#include <linux/sched.h>
23#include <linux/kernel.h>
24#include <linux/smp.h>
25#include <linux/cpu.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070026#include <linux/sysctl.h>
Tony Breeds1ad74992007-09-21 13:26:03 +100027#include <linux/tick.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070028
29#include <asm/system.h>
30#include <asm/processor.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070031#include <asm/cputable.h>
32#include <asm/time.h>
Michael Ellermanfd899c02005-07-07 17:56:28 -070033#include <asm/machdep.h>
Paul Mackerras2249ca92005-11-07 13:18:13 +110034#include <asm/smp.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070035
Paul Mackerrasa0652fc2006-03-27 15:03:03 +110036#ifdef CONFIG_HOTPLUG_CPU
Johannes Berg61e99162008-09-24 22:56:25 +000037#define cpu_should_die() cpu_is_offline(smp_processor_id())
Paul Mackerrasa0652fc2006-03-27 15:03:03 +110038#else
39#define cpu_should_die() 0
40#endif
Linus Torvalds1da177e2005-04-16 15:20:36 -070041
arnd@arndb.de302eca12006-10-24 18:31:26 +020042static int __init powersave_off(char *arg)
43{
44 ppc_md.power_save = NULL;
45 return 0;
46}
47__setup("powersave=off", powersave_off);
48
Paul Mackerrasa0652fc2006-03-27 15:03:03 +110049/*
50 * The body of the idle task.
51 */
52void cpu_idle(void)
Linus Torvalds1da177e2005-04-16 15:20:36 -070053{
Paul Mackerrasa0652fc2006-03-27 15:03:03 +110054 if (ppc_md.idle_loop)
55 ppc_md.idle_loop(); /* doesn't return */
56
Nick Piggin64c7c8f2005-11-08 21:39:04 -080057 set_thread_flag(TIF_POLLING_NRFLAG);
Linus Torvalds1da177e2005-04-16 15:20:36 -070058 while (1) {
Thomas Gleixnerb8f8c3c2008-07-18 17:27:28 +020059 tick_nohz_stop_sched_tick(1);
Paul Mackerrasa0652fc2006-03-27 15:03:03 +110060 while (!need_resched() && !cpu_should_die()) {
Anton Blanchardddafddc2006-04-02 19:54:09 +100061 ppc64_runlatch_off();
62
Paul Mackerrasa0652fc2006-03-27 15:03:03 +110063 if (ppc_md.power_save) {
64 clear_thread_flag(TIF_POLLING_NRFLAG);
65 /*
66 * smp_mb is so clearing of TIF_POLLING_NRFLAG
67 * is ordered w.r.t. need_resched() test.
68 */
69 smp_mb();
70 local_irq_disable();
71
Steven Rostedt6d07bb42008-11-14 16:21:19 -080072 /* Don't trace irqs off for idle */
73 stop_critical_timings();
74
Paul Mackerrasa0652fc2006-03-27 15:03:03 +110075 /* check again after disabling irqs */
76 if (!need_resched() && !cpu_should_die())
77 ppc_md.power_save();
78
Steven Rostedt6d07bb42008-11-14 16:21:19 -080079 start_critical_timings();
80
Paul Mackerrasa0652fc2006-03-27 15:03:03 +110081 local_irq_enable();
82 set_thread_flag(TIF_POLLING_NRFLAG);
83
84 } else {
Linus Torvalds1da177e2005-04-16 15:20:36 -070085 /*
86 * Go into low thread priority and possibly
87 * low power mode.
88 */
89 HMT_low();
90 HMT_very_low();
91 }
Linus Torvalds1da177e2005-04-16 15:20:36 -070092 }
93
Paul Mackerrasa0652fc2006-03-27 15:03:03 +110094 HMT_medium();
Anton Blanchard45e75df2005-07-07 17:56:33 -070095 ppc64_runlatch_on();
Tony Breeds1ad74992007-09-21 13:26:03 +100096 tick_nohz_restart_sched_tick();
Paul Mackerrasa0652fc2006-03-27 15:03:03 +110097 if (cpu_should_die())
98 cpu_die();
Nick Piggin5bfb5d62005-11-08 21:39:01 -080099 preempt_enable_no_resched();
Linus Torvalds1da177e2005-04-16 15:20:36 -0700100 schedule();
Nick Piggin5bfb5d62005-11-08 21:39:01 -0800101 preempt_disable();
Linus Torvalds1da177e2005-04-16 15:20:36 -0700102 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700103}
104
Linus Torvalds1da177e2005-04-16 15:20:36 -0700105int powersave_nap;
106
107#ifdef CONFIG_SYSCTL
108/*
109 * Register the sysctl to set/clear powersave_nap.
110 */
111static ctl_table powersave_nap_ctl_table[]={
112 {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700113 .procname = "powersave-nap",
114 .data = &powersave_nap,
115 .maxlen = sizeof(int),
116 .mode = 0644,
Eric W. Biederman6d456112009-11-16 03:11:48 -0800117 .proc_handler = proc_dointvec,
Linus Torvalds1da177e2005-04-16 15:20:36 -0700118 },
Eric W. Biedermanf5f10672007-02-14 00:33:46 -0800119 {}
Linus Torvalds1da177e2005-04-16 15:20:36 -0700120};
121static ctl_table powersave_nap_sysctl_root[] = {
Eric W. Biedermanf5f10672007-02-14 00:33:46 -0800122 {
Eric W. Biedermanf5f10672007-02-14 00:33:46 -0800123 .procname = "kernel",
Alexey Dobriyanfb293ae2007-10-28 05:34:53 +1100124 .mode = 0555,
Eric W. Biedermanf5f10672007-02-14 00:33:46 -0800125 .child = powersave_nap_ctl_table,
126 },
127 {}
Linus Torvalds1da177e2005-04-16 15:20:36 -0700128};
129
130static int __init
131register_powersave_nap_sysctl(void)
132{
Eric W. Biederman0b4d4142007-02-14 00:34:09 -0800133 register_sysctl_table(powersave_nap_sysctl_root);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700134
135 return 0;
136}
137__initcall(register_powersave_nap_sysctl);
138#endif