Merge with /pub/scm/linux/kernel/git/torvalds/linux-2.6.git
[linux-2.6] / arch / powerpc / kernel / idle_64.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  *
7  * iSeries supported added by Mike Corrigan <mikejc@us.ibm.com>
8  *
9  * Additional shared processor, SMT, and firmware support
10  *    Copyright (c) 2003 Dave Engebretsen <engebret@us.ibm.com>
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
18 #include <linux/config.h>
19 #include <linux/sched.h>
20 #include <linux/kernel.h>
21 #include <linux/smp.h>
22 #include <linux/cpu.h>
23 #include <linux/sysctl.h>
24
25 #include <asm/system.h>
26 #include <asm/processor.h>
27 #include <asm/cputable.h>
28 #include <asm/time.h>
29 #include <asm/machdep.h>
30 #include <asm/smp.h>
31
32 extern void power4_idle(void);
33
34 void default_idle(void)
35 {
36         unsigned int cpu = smp_processor_id();
37         set_thread_flag(TIF_POLLING_NRFLAG);
38
39         while (1) {
40                 if (!need_resched()) {
41                         while (!need_resched() && !cpu_is_offline(cpu)) {
42                                 ppc64_runlatch_off();
43
44                                 /*
45                                  * Go into low thread priority and possibly
46                                  * low power mode.
47                                  */
48                                 HMT_low();
49                                 HMT_very_low();
50                         }
51
52                         HMT_medium();
53                 }
54
55                 ppc64_runlatch_on();
56                 preempt_enable_no_resched();
57                 schedule();
58                 preempt_disable();
59                 if (cpu_is_offline(cpu) && system_state == SYSTEM_RUNNING)
60                         cpu_die();
61         }
62 }
63
64 void native_idle(void)
65 {
66         while (1) {
67                 ppc64_runlatch_off();
68
69                 if (!need_resched())
70                         power4_idle();
71
72                 if (need_resched()) {
73                         ppc64_runlatch_on();
74                         preempt_enable_no_resched();
75                         schedule();
76                         preempt_disable();
77                 }
78
79                 if (cpu_is_offline(smp_processor_id()) &&
80                     system_state == SYSTEM_RUNNING)
81                         cpu_die();
82         }
83 }
84
85 void cpu_idle(void)
86 {
87         BUG_ON(NULL == ppc_md.idle_loop);
88         ppc_md.idle_loop();
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