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Commit | Line | Data |
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1da177e4 LT |
1 | /* |
2 | * Idle daemon for PowerPC. Idle daemon will handle any action | |
3 | * that needs to be taken when the system becomes idle. | |
4 | * | |
a0652fc9 PM |
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. | |
1da177e4 LT |
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 | * | |
a0652fc9 PM |
14 | * 32-bit and 64-bit versions merged by Paul Mackerras <paulus@samba.org> |
15 | * | |
1da177e4 LT |
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 | ||
1da177e4 LT |
22 | #include <linux/sched.h> |
23 | #include <linux/kernel.h> | |
24 | #include <linux/smp.h> | |
25 | #include <linux/cpu.h> | |
1da177e4 | 26 | #include <linux/sysctl.h> |
1ad74998 | 27 | #include <linux/tick.h> |
1da177e4 LT |
28 | |
29 | #include <asm/system.h> | |
30 | #include <asm/processor.h> | |
1da177e4 LT |
31 | #include <asm/cputable.h> |
32 | #include <asm/time.h> | |
fd899c0c | 33 | #include <asm/machdep.h> |
2249ca9d | 34 | #include <asm/smp.h> |
1da177e4 | 35 | |
a0652fc9 | 36 | #ifdef CONFIG_HOTPLUG_CPU |
61e9916e | 37 | #define cpu_should_die() cpu_is_offline(smp_processor_id()) |
a0652fc9 PM |
38 | #else |
39 | #define cpu_should_die() 0 | |
40 | #endif | |
1da177e4 | 41 | |
302eca18 AB |
42 | static int __init powersave_off(char *arg) |
43 | { | |
44 | ppc_md.power_save = NULL; | |
45 | return 0; | |
46 | } | |
47 | __setup("powersave=off", powersave_off); | |
48 | ||
a0652fc9 PM |
49 | /* |
50 | * The body of the idle task. | |
51 | */ | |
52 | void cpu_idle(void) | |
1da177e4 | 53 | { |
a0652fc9 PM |
54 | if (ppc_md.idle_loop) |
55 | ppc_md.idle_loop(); /* doesn't return */ | |
1da177e4 | 56 | |
a0652fc9 | 57 | set_thread_flag(TIF_POLLING_NRFLAG); |
1da177e4 | 58 | while (1) { |
b8f8c3cf | 59 | tick_nohz_stop_sched_tick(1); |
a0652fc9 | 60 | while (!need_resched() && !cpu_should_die()) { |
ddafddcf AB |
61 | ppc64_runlatch_off(); |
62 | ||
a0652fc9 PM |
63 | 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 | ||
6d07bb47 SR |
72 | /* Don't trace irqs off for idle */ |
73 | stop_critical_timings(); | |
74 | ||
a0652fc9 PM |
75 | /* check again after disabling irqs */ |
76 | if (!need_resched() && !cpu_should_die()) | |
77 | ppc_md.power_save(); | |
78 | ||
6d07bb47 SR |
79 | start_critical_timings(); |
80 | ||
a0652fc9 PM |
81 | local_irq_enable(); |
82 | set_thread_flag(TIF_POLLING_NRFLAG); | |
83 | ||
84 | } else { | |
1da177e4 LT |
85 | /* |
86 | * Go into low thread priority and possibly | |
87 | * low power mode. | |
88 | */ | |
89 | HMT_low(); | |
90 | HMT_very_low(); | |
91 | } | |
1da177e4 LT |
92 | } |
93 | ||
a0652fc9 | 94 | HMT_medium(); |
45e75dfb | 95 | ppc64_runlatch_on(); |
1ad74998 | 96 | tick_nohz_restart_sched_tick(); |
a7c2bb82 | 97 | preempt_enable_no_resched(); |
a0652fc9 PM |
98 | if (cpu_should_die()) |
99 | cpu_die(); | |
1da177e4 | 100 | schedule(); |
5bfb5d69 | 101 | preempt_disable(); |
1da177e4 | 102 | } |
1da177e4 LT |
103 | } |
104 | ||
1da177e4 LT |
105 | int powersave_nap; |
106 | ||
107 | #ifdef CONFIG_SYSCTL | |
108 | /* | |
109 | * Register the sysctl to set/clear powersave_nap. | |
110 | */ | |
111 | static ctl_table powersave_nap_ctl_table[]={ | |
112 | { | |
1da177e4 LT |
113 | .procname = "powersave-nap", |
114 | .data = &powersave_nap, | |
115 | .maxlen = sizeof(int), | |
116 | .mode = 0644, | |
6d456111 | 117 | .proc_handler = proc_dointvec, |
1da177e4 | 118 | }, |
f5f10678 | 119 | {} |
1da177e4 LT |
120 | }; |
121 | static ctl_table powersave_nap_sysctl_root[] = { | |
f5f10678 | 122 | { |
f5f10678 | 123 | .procname = "kernel", |
fb293ae1 | 124 | .mode = 0555, |
f5f10678 EB |
125 | .child = powersave_nap_ctl_table, |
126 | }, | |
127 | {} | |
1da177e4 LT |
128 | }; |
129 | ||
130 | static int __init | |
131 | register_powersave_nap_sysctl(void) | |
132 | { | |
0b4d4147 | 133 | register_sysctl_table(powersave_nap_sysctl_root); |
1da177e4 LT |
134 | |
135 | return 0; | |
136 | } | |
137 | __initcall(register_powersave_nap_sysctl); | |
138 | #endif |