[POWERPC] Fix typo: MMCR0_PMA0 != MMCR0_PMAO
[linux-2.6] / 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 /* this is used for software suspend, and that shuts down
37  * CPUs even while the system is still booting... */
38 #define cpu_should_die()        (cpu_is_offline(smp_processor_id()) && \
39                                    (system_state == SYSTEM_RUNNING     \
40                                  || system_state == SYSTEM_BOOTING))
41 #else
42 #define cpu_should_die()        0
43 #endif
44
45 static int __init powersave_off(char *arg)
46 {
47         ppc_md.power_save = NULL;
48         return 0;
49 }
50 __setup("powersave=off", powersave_off);
51
52 /*
53  * The body of the idle task.
54  */
55 void cpu_idle(void)
56 {
57         if (ppc_md.idle_loop)
58                 ppc_md.idle_loop();     /* doesn't return */
59
60         set_thread_flag(TIF_POLLING_NRFLAG);
61         while (1) {
62                 while (!need_resched() && !cpu_should_die()) {
63                         ppc64_runlatch_off();
64
65                         if (ppc_md.power_save) {
66                                 clear_thread_flag(TIF_POLLING_NRFLAG);
67                                 /*
68                                  * smp_mb is so clearing of TIF_POLLING_NRFLAG
69                                  * is ordered w.r.t. need_resched() test.
70                                  */
71                                 smp_mb();
72                                 local_irq_disable();
73
74                                 /* check again after disabling irqs */
75                                 if (!need_resched() && !cpu_should_die())
76                                         ppc_md.power_save();
77
78                                 local_irq_enable();
79                                 set_thread_flag(TIF_POLLING_NRFLAG);
80
81                         } else {
82                                 /*
83                                  * Go into low thread priority and possibly
84                                  * low power mode.
85                                  */
86                                 HMT_low();
87                                 HMT_very_low();
88                         }
89                 }
90
91                 HMT_medium();
92                 ppc64_runlatch_on();
93                 if (cpu_should_die())
94                         cpu_die();
95                 preempt_enable_no_resched();
96                 schedule();
97                 preempt_disable();
98         }
99 }
100
101 int powersave_nap;
102
103 #ifdef CONFIG_SYSCTL
104 /*
105  * Register the sysctl to set/clear powersave_nap.
106  */
107 static ctl_table powersave_nap_ctl_table[]={
108         {
109                 .ctl_name       = KERN_PPC_POWERSAVE_NAP,
110                 .procname       = "powersave-nap",
111                 .data           = &powersave_nap,
112                 .maxlen         = sizeof(int),
113                 .mode           = 0644,
114                 .proc_handler   = &proc_dointvec,
115         },
116         {}
117 };
118 static ctl_table powersave_nap_sysctl_root[] = {
119         {
120                 .ctl_name       = CTL_KERN,
121                 .procname       = "kernel",
122                 .mode           = 0755,
123                 .child          = powersave_nap_ctl_table,
124         },
125         {}
126 };
127
128 static int __init
129 register_powersave_nap_sysctl(void)
130 {
131         register_sysctl_table(powersave_nap_sysctl_root);
132
133         return 0;
134 }
135 __initcall(register_powersave_nap_sysctl);
136 #endif