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 |
543b9fd3 JB |
37 | /* this is used for software suspend, and that shuts down |
38 | * CPUs even while the system is still booting... */ | |
a0652fc9 | 39 | #define cpu_should_die() (cpu_is_offline(smp_processor_id()) && \ |
543b9fd3 JB |
40 | (system_state == SYSTEM_RUNNING \ |
41 | || system_state == SYSTEM_BOOTING)) | |
a0652fc9 PM |
42 | #else |
43 | #define cpu_should_die() 0 | |
44 | #endif | |
1da177e4 | 45 | |
302eca18 AB |
46 | static int __init powersave_off(char *arg) |
47 | { | |
48 | ppc_md.power_save = NULL; | |
49 | return 0; | |
50 | } | |
51 | __setup("powersave=off", powersave_off); | |
52 | ||
a0652fc9 PM |
53 | /* |
54 | * The body of the idle task. | |
55 | */ | |
56 | void cpu_idle(void) | |
1da177e4 | 57 | { |
a0652fc9 PM |
58 | if (ppc_md.idle_loop) |
59 | ppc_md.idle_loop(); /* doesn't return */ | |
1da177e4 | 60 | |
a0652fc9 | 61 | set_thread_flag(TIF_POLLING_NRFLAG); |
1da177e4 | 62 | while (1) { |
b8f8c3cf | 63 | tick_nohz_stop_sched_tick(1); |
a0652fc9 | 64 | while (!need_resched() && !cpu_should_die()) { |
ddafddcf AB |
65 | ppc64_runlatch_off(); |
66 | ||
a0652fc9 PM |
67 | if (ppc_md.power_save) { |
68 | clear_thread_flag(TIF_POLLING_NRFLAG); | |
69 | /* | |
70 | * smp_mb is so clearing of TIF_POLLING_NRFLAG | |
71 | * is ordered w.r.t. need_resched() test. | |
72 | */ | |
73 | smp_mb(); | |
74 | local_irq_disable(); | |
75 | ||
76 | /* check again after disabling irqs */ | |
77 | if (!need_resched() && !cpu_should_die()) | |
78 | ppc_md.power_save(); | |
79 | ||
80 | local_irq_enable(); | |
81 | set_thread_flag(TIF_POLLING_NRFLAG); | |
82 | ||
83 | } else { | |
1da177e4 LT |
84 | /* |
85 | * Go into low thread priority and possibly | |
86 | * low power mode. | |
87 | */ | |
88 | HMT_low(); | |
89 | HMT_very_low(); | |
90 | } | |
1da177e4 LT |
91 | } |
92 | ||
a0652fc9 | 93 | HMT_medium(); |
45e75dfb | 94 | ppc64_runlatch_on(); |
1ad74998 | 95 | tick_nohz_restart_sched_tick(); |
a0652fc9 PM |
96 | if (cpu_should_die()) |
97 | cpu_die(); | |
5bfb5d69 | 98 | preempt_enable_no_resched(); |
1da177e4 | 99 | schedule(); |
5bfb5d69 | 100 | preempt_disable(); |
1da177e4 | 101 | } |
1da177e4 LT |
102 | } |
103 | ||
1da177e4 LT |
104 | int powersave_nap; |
105 | ||
106 | #ifdef CONFIG_SYSCTL | |
107 | /* | |
108 | * Register the sysctl to set/clear powersave_nap. | |
109 | */ | |
110 | static ctl_table powersave_nap_ctl_table[]={ | |
111 | { | |
112 | .ctl_name = KERN_PPC_POWERSAVE_NAP, | |
113 | .procname = "powersave-nap", | |
114 | .data = &powersave_nap, | |
115 | .maxlen = sizeof(int), | |
116 | .mode = 0644, | |
117 | .proc_handler = &proc_dointvec, | |
118 | }, | |
f5f10678 | 119 | {} |
1da177e4 LT |
120 | }; |
121 | static ctl_table powersave_nap_sysctl_root[] = { | |
f5f10678 EB |
122 | { |
123 | .ctl_name = CTL_KERN, | |
124 | .procname = "kernel", | |
fb293ae1 | 125 | .mode = 0555, |
f5f10678 EB |
126 | .child = powersave_nap_ctl_table, |
127 | }, | |
128 | {} | |
1da177e4 LT |
129 | }; |
130 | ||
131 | static int __init | |
132 | register_powersave_nap_sysctl(void) | |
133 | { | |
0b4d4147 | 134 | register_sysctl_table(powersave_nap_sysctl_root); |
1da177e4 LT |
135 | |
136 | return 0; | |
137 | } | |
138 | __initcall(register_powersave_nap_sysctl); | |
139 | #endif |