Remove obsolete #include <linux/config.h>
[linux-2.6.git] / arch / powerpc / kernel / idle.c
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
28 #include <asm/system.h>
29 #include <asm/processor.h>
30 #include <asm/cputable.h>
31 #include <asm/time.h>
32 #include <asm/machdep.h>
33 #include <asm/smp.h>
34
35 #ifdef CONFIG_HOTPLUG_CPU
36 #define cpu_should_die()        (cpu_is_offline(smp_processor_id()) && \
37                                  system_state == SYSTEM_RUNNING)
38 #else
39 #define cpu_should_die()        0
40 #endif
41
42 /*
43  * The body of the idle task.
44  */
45 void cpu_idle(void)
46 {
47         if (ppc_md.idle_loop)
48                 ppc_md.idle_loop();     /* doesn't return */
49
50         set_thread_flag(TIF_POLLING_NRFLAG);
51         while (1) {
52                 while (!need_resched() && !cpu_should_die()) {
53                         ppc64_runlatch_off();
54
55                         if (ppc_md.power_save) {
56                                 clear_thread_flag(TIF_POLLING_NRFLAG);
57                                 /*
58                                  * smp_mb is so clearing of TIF_POLLING_NRFLAG
59                                  * is ordered w.r.t. need_resched() test.
60                                  */
61                                 smp_mb();
62                                 local_irq_disable();
63
64                                 /* check again after disabling irqs */
65                                 if (!need_resched() && !cpu_should_die())
66                                         ppc_md.power_save();
67
68                                 local_irq_enable();
69                                 set_thread_flag(TIF_POLLING_NRFLAG);
70
71                         } else {
72                                 /*
73                                  * Go into low thread priority and possibly
74                                  * low power mode.
75                                  */
76                                 HMT_low();
77                                 HMT_very_low();
78                         }
79                 }
80
81                 HMT_medium();
82                 ppc64_runlatch_on();
83                 if (cpu_should_die())
84                         cpu_die();
85                 preempt_enable_no_resched();
86                 schedule();
87                 preempt_disable();
88         }
89 }
90
91 int powersave_nap;
92
93 #ifdef CONFIG_SYSCTL
94 /*
95  * Register the sysctl to set/clear powersave_nap.
96  */
97 static ctl_table powersave_nap_ctl_table[]={
98         {
99                 .ctl_name       = KERN_PPC_POWERSAVE_NAP,
100                 .procname       = "powersave-nap",
101                 .data           = &powersave_nap,
102                 .maxlen         = sizeof(int),
103                 .mode           = 0644,
104                 .proc_handler   = &proc_dointvec,
105         },
106         { 0, },
107 };
108 static ctl_table powersave_nap_sysctl_root[] = {
109         { 1, "kernel", NULL, 0, 0755, powersave_nap_ctl_table, },
110         { 0,},
111 };
112
113 static int __init
114 register_powersave_nap_sysctl(void)
115 {
116         register_sysctl_table(powersave_nap_sysctl_root, 0);
117
118         return 0;
119 }
120 __initcall(register_powersave_nap_sysctl);
121 #endif