2 * Idle daemon for PowerPC. Idle daemon will handle any action
3 * that needs to be taken when the system becomes idle.
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.
9 * iSeries supported added by Mike Corrigan <mikejc@us.ibm.com>
11 * Additional shared processor, SMT, and firmware support
12 * Copyright (c) 2003 Dave Engebretsen <engebret@us.ibm.com>
14 * 32-bit and 64-bit versions merged by Paul Mackerras <paulus@samba.org>
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.
22 #include <linux/config.h>
23 #include <linux/sched.h>
24 #include <linux/kernel.h>
25 #include <linux/smp.h>
26 #include <linux/cpu.h>
27 #include <linux/sysctl.h>
29 #include <asm/system.h>
30 #include <asm/processor.h>
31 #include <asm/cputable.h>
33 #include <asm/machdep.h>
36 #ifdef CONFIG_HOTPLUG_CPU
37 #define cpu_should_die() (cpu_is_offline(smp_processor_id()) && \
38 system_state == SYSTEM_RUNNING)
40 #define cpu_should_die() 0
44 * The body of the idle task.
49 ppc_md
.idle_loop(); /* doesn't return */
51 set_thread_flag(TIF_POLLING_NRFLAG
);
53 while (!need_resched() && !cpu_should_die()) {
56 if (ppc_md
.power_save
) {
57 clear_thread_flag(TIF_POLLING_NRFLAG
);
59 * smp_mb is so clearing of TIF_POLLING_NRFLAG
60 * is ordered w.r.t. need_resched() test.
65 /* check again after disabling irqs */
66 if (!need_resched() && !cpu_should_die())
70 set_thread_flag(TIF_POLLING_NRFLAG
);
74 * Go into low thread priority and possibly
86 preempt_enable_no_resched();
96 * Register the sysctl to set/clear powersave_nap.
98 static ctl_table powersave_nap_ctl_table
[]={
100 .ctl_name
= KERN_PPC_POWERSAVE_NAP
,
101 .procname
= "powersave-nap",
102 .data
= &powersave_nap
,
103 .maxlen
= sizeof(int),
105 .proc_handler
= &proc_dointvec
,
109 static ctl_table powersave_nap_sysctl_root
[] = {
110 { 1, "kernel", NULL
, 0, 0755, powersave_nap_ctl_table
, },
115 register_powersave_nap_sysctl(void)
117 register_sysctl_table(powersave_nap_sysctl_root
, 0);
121 __initcall(register_powersave_nap_sysctl
);