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1// SPDX-License-Identifier: GPL-2.0-or-later
2/*
3 * Idle daemon for PowerPC. Idle daemon will handle any action
4 * that needs to be taken when the system becomes idle.
5 *
6 * Originally written by Cort Dougan (cort@cs.nmt.edu).
7 * Subsequent 32-bit hacking by Tom Rini, Armin Kuster,
8 * Paul Mackerras and others.
9 *
10 * iSeries supported added by Mike Corrigan <mikejc@us.ibm.com>
11 *
12 * Additional shared processor, SMT, and firmware support
13 * Copyright (c) 2003 Dave Engebretsen <engebret@us.ibm.com>
14 *
15 * 32-bit and 64-bit versions merged by Paul Mackerras <paulus@samba.org>
16 */
17
18#include <linux/sched.h>
19#include <linux/kernel.h>
20#include <linux/smp.h>
21#include <linux/cpu.h>
22#include <linux/sysctl.h>
23#include <linux/tick.h>
24
25#include <asm/processor.h>
26#include <asm/cputable.h>
27#include <asm/time.h>
28#include <asm/machdep.h>
29#include <asm/runlatch.h>
30#include <asm/smp.h>
31
32
33unsigned long cpuidle_disable = IDLE_NO_OVERRIDE;
34EXPORT_SYMBOL(cpuidle_disable);
35
36static int __init powersave_off(char *arg)
37{
38 ppc_md.power_save = NULL;
39 cpuidle_disable = IDLE_POWERSAVE_OFF;
40 return 1;
41}
42__setup("powersave=off", powersave_off);
43
44void arch_cpu_idle(void)
45{
46 ppc64_runlatch_off();
47
48 if (ppc_md.power_save) {
49 ppc_md.power_save();
50 /*
51 * Some power_save functions return with
52 * interrupts enabled, some don't.
53 */
54 if (irqs_disabled())
55 raw_local_irq_enable();
56 } else {
57 raw_local_irq_enable();
58 /*
59 * Go into low thread priority and possibly
60 * low power mode.
61 */
62 HMT_low();
63 HMT_very_low();
64 }
65
66 HMT_medium();
67 ppc64_runlatch_on();
68}
69
70int powersave_nap;
71
72#ifdef CONFIG_PPC_970_NAP
73void power4_idle(void)
74{
75 if (!cpu_has_feature(CPU_FTR_CAN_NAP))
76 return;
77
78 if (!powersave_nap)
79 return;
80
81 if (!prep_irq_for_idle())
82 return;
83
84 if (cpu_has_feature(CPU_FTR_ALTIVEC))
85 asm volatile(PPC_DSSALL " ; sync" ::: "memory");
86
87 power4_idle_nap();
88
89 /*
90 * power4_idle_nap returns with interrupts enabled (soft and hard).
91 * to our caller with interrupts enabled (soft and hard). Our caller
92 * can cope with either interrupts disabled or enabled upon return.
93 */
94}
95#endif
96
97#ifdef CONFIG_SYSCTL
98/*
99 * Register the sysctl to set/clear powersave_nap.
100 */
101static struct ctl_table powersave_nap_ctl_table[] = {
102 {
103 .procname = "powersave-nap",
104 .data = &powersave_nap,
105 .maxlen = sizeof(int),
106 .mode = 0644,
107 .proc_handler = proc_dointvec,
108 },
109 {}
110};
111static struct ctl_table powersave_nap_sysctl_root[] = {
112 {
113 .procname = "kernel",
114 .mode = 0555,
115 .child = powersave_nap_ctl_table,
116 },
117 {}
118};
119
120static int __init
121register_powersave_nap_sysctl(void)
122{
123 register_sysctl_table(powersave_nap_sysctl_root);
124
125 return 0;
126}
127__initcall(register_powersave_nap_sysctl);
128#endif
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#include <linux/tick.h>
28
29#include <asm/processor.h>
30#include <asm/cputable.h>
31#include <asm/time.h>
32#include <asm/machdep.h>
33#include <asm/runlatch.h>
34#include <asm/smp.h>
35
36#ifdef CONFIG_HOTPLUG_CPU
37#define cpu_should_die() cpu_is_offline(smp_processor_id())
38#else
39#define cpu_should_die() 0
40#endif
41
42unsigned long cpuidle_disable = IDLE_NO_OVERRIDE;
43EXPORT_SYMBOL(cpuidle_disable);
44
45static int __init powersave_off(char *arg)
46{
47 ppc_md.power_save = NULL;
48 cpuidle_disable = IDLE_POWERSAVE_OFF;
49 return 0;
50}
51__setup("powersave=off", powersave_off);
52
53/*
54 * The body of the idle task.
55 */
56void cpu_idle(void)
57{
58 if (ppc_md.idle_loop)
59 ppc_md.idle_loop(); /* doesn't return */
60
61 set_thread_flag(TIF_POLLING_NRFLAG);
62 while (1) {
63 tick_nohz_idle_enter();
64 rcu_idle_enter();
65
66 while (!need_resched() && !cpu_should_die()) {
67 ppc64_runlatch_off();
68
69 if (ppc_md.power_save) {
70 clear_thread_flag(TIF_POLLING_NRFLAG);
71 /*
72 * smp_mb is so clearing of TIF_POLLING_NRFLAG
73 * is ordered w.r.t. need_resched() test.
74 */
75 smp_mb();
76 local_irq_disable();
77
78 /* Don't trace irqs off for idle */
79 stop_critical_timings();
80
81 /* check again after disabling irqs */
82 if (!need_resched() && !cpu_should_die())
83 ppc_md.power_save();
84
85 start_critical_timings();
86
87 /* Some power_save functions return with
88 * interrupts enabled, some don't.
89 */
90 if (irqs_disabled())
91 local_irq_enable();
92 set_thread_flag(TIF_POLLING_NRFLAG);
93
94 } else {
95 /*
96 * Go into low thread priority and possibly
97 * low power mode.
98 */
99 HMT_low();
100 HMT_very_low();
101 }
102 }
103
104 HMT_medium();
105 ppc64_runlatch_on();
106 rcu_idle_exit();
107 tick_nohz_idle_exit();
108 if (cpu_should_die()) {
109 sched_preempt_enable_no_resched();
110 cpu_die();
111 }
112 schedule_preempt_disabled();
113 }
114}
115
116int powersave_nap;
117
118#ifdef CONFIG_SYSCTL
119/*
120 * Register the sysctl to set/clear powersave_nap.
121 */
122static ctl_table powersave_nap_ctl_table[]={
123 {
124 .procname = "powersave-nap",
125 .data = &powersave_nap,
126 .maxlen = sizeof(int),
127 .mode = 0644,
128 .proc_handler = proc_dointvec,
129 },
130 {}
131};
132static ctl_table powersave_nap_sysctl_root[] = {
133 {
134 .procname = "kernel",
135 .mode = 0555,
136 .child = powersave_nap_ctl_table,
137 },
138 {}
139};
140
141static int __init
142register_powersave_nap_sysctl(void)
143{
144 register_sysctl_table(powersave_nap_sysctl_root);
145
146 return 0;
147}
148__initcall(register_powersave_nap_sysctl);
149#endif