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authorPaul Mackerras <paulus@samba.org>2006-03-26 23:03:03 -0500
committerPaul Mackerras <paulus@samba.org>2006-03-26 23:03:03 -0500
commita0652fc9a28c3ef8cd59264bfcb089c44d1b0e06 (patch)
treea28527b65237b3067553a993f5ad06dfb24df044 /arch/powerpc/kernel/idle.c
parent55aab8cd3a498201b769a19de861c77516bdfd45 (diff)
powerpc: Unify the 32 and 64 bit idle loops
This unifies the 32-bit (ARCH=ppc and ARCH=powerpc) and 64-bit idle loops. It brings over the concept of having a ppc_md.power_save function from 32-bit to ARCH=powerpc, which lets us get rid of native_idle(). With this we will also be able to simplify the idle handling for pSeries and cell. Signed-off-by: Paul Mackerras <paulus@samba.org>
Diffstat (limited to 'arch/powerpc/kernel/idle.c')
-rw-r--r--arch/powerpc/kernel/idle.c122
1 files changed, 122 insertions, 0 deletions
diff --git a/arch/powerpc/kernel/idle.c b/arch/powerpc/kernel/idle.c
new file mode 100644
index 000000000000..e9f321d74d85
--- /dev/null
+++ b/arch/powerpc/kernel/idle.c
@@ -0,0 +1,122 @@
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/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>
28
29#include <asm/system.h>
30#include <asm/processor.h>
31#include <asm/cputable.h>
32#include <asm/time.h>
33#include <asm/machdep.h>
34#include <asm/smp.h>
35
36#ifdef CONFIG_HOTPLUG_CPU
37#define cpu_should_die() (cpu_is_offline(smp_processor_id()) && \
38 system_state == SYSTEM_RUNNING)
39#else
40#define cpu_should_die() 0
41#endif
42
43/*
44 * The body of the idle task.
45 */
46void cpu_idle(void)
47{
48 if (ppc_md.idle_loop)
49 ppc_md.idle_loop(); /* doesn't return */
50
51 set_thread_flag(TIF_POLLING_NRFLAG);
52 while (1) {
53 ppc64_runlatch_off();
54
55 while (!need_resched() && !cpu_should_die()) {
56 if (ppc_md.power_save) {
57 clear_thread_flag(TIF_POLLING_NRFLAG);
58 /*
59 * smp_mb is so clearing of TIF_POLLING_NRFLAG
60 * is ordered w.r.t. need_resched() test.
61 */
62 smp_mb();
63 local_irq_disable();
64
65 /* check again after disabling irqs */
66 if (!need_resched() && !cpu_should_die())
67 ppc_md.power_save();
68
69 local_irq_enable();
70 set_thread_flag(TIF_POLLING_NRFLAG);
71
72 } else {
73 /*
74 * Go into low thread priority and possibly
75 * low power mode.
76 */
77 HMT_low();
78 HMT_very_low();
79 }
80 }
81
82 HMT_medium();
83 ppc64_runlatch_on();
84 if (cpu_should_die())
85 cpu_die();
86 preempt_enable_no_resched();
87 schedule();
88 preempt_disable();
89 }
90}
91
92int powersave_nap;
93
94#ifdef CONFIG_SYSCTL
95/*
96 * Register the sysctl to set/clear powersave_nap.
97 */
98static ctl_table powersave_nap_ctl_table[]={
99 {
100 .ctl_name = KERN_PPC_POWERSAVE_NAP,
101 .procname = "powersave-nap",
102 .data = &powersave_nap,
103 .maxlen = sizeof(int),
104 .mode = 0644,
105 .proc_handler = &proc_dointvec,
106 },
107 { 0, },
108};
109static ctl_table powersave_nap_sysctl_root[] = {
110 { 1, "kernel", NULL, 0, 0755, powersave_nap_ctl_table, },
111 { 0,},
112};
113
114static int __init
115register_powersave_nap_sysctl(void)
116{
117 register_sysctl_table(powersave_nap_sysctl_root, 0);
118
119 return 0;
120}
121__initcall(register_powersave_nap_sysctl);
122#endif