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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 0;
41}
42__setup("powersave=off", powersave_off);
43
44#ifdef CONFIG_HOTPLUG_CPU
45void arch_cpu_idle_dead(void)
46{
47 sched_preempt_enable_no_resched();
48 cpu_die();
49}
50#endif
51
52void arch_cpu_idle(void)
53{
54 ppc64_runlatch_off();
55
56 if (ppc_md.power_save) {
57 ppc_md.power_save();
58 /*
59 * Some power_save functions return with
60 * interrupts enabled, some don't.
61 */
62 if (irqs_disabled())
63 local_irq_enable();
64 } else {
65 local_irq_enable();
66 /*
67 * Go into low thread priority and possibly
68 * low power mode.
69 */
70 HMT_low();
71 HMT_very_low();
72 }
73
74 HMT_medium();
75 ppc64_runlatch_on();
76}
77
78int powersave_nap;
79
80#ifdef CONFIG_PPC_970_NAP
81void power4_idle(void)
82{
83 if (!cpu_has_feature(CPU_FTR_CAN_NAP))
84 return;
85
86 if (!powersave_nap)
87 return;
88
89 if (!prep_irq_for_idle())
90 return;
91
92 if (cpu_has_feature(CPU_FTR_ALTIVEC))
93 asm volatile("DSSALL ; sync" ::: "memory");
94
95 power4_idle_nap();
96
97 /*
98 * power4_idle_nap returns with interrupts enabled (soft and hard).
99 * to our caller with interrupts enabled (soft and hard). Our caller
100 * can cope with either interrupts disabled or enabled upon return.
101 */
102}
103#endif
104
105#ifdef CONFIG_SYSCTL
106/*
107 * Register the sysctl to set/clear powersave_nap.
108 */
109static struct ctl_table powersave_nap_ctl_table[] = {
110 {
111 .procname = "powersave-nap",
112 .data = &powersave_nap,
113 .maxlen = sizeof(int),
114 .mode = 0644,
115 .proc_handler = proc_dointvec,
116 },
117 {}
118};
119static struct ctl_table powersave_nap_sysctl_root[] = {
120 {
121 .procname = "kernel",
122 .mode = 0555,
123 .child = powersave_nap_ctl_table,
124 },
125 {}
126};
127
128static int __init
129register_powersave_nap_sysctl(void)
130{
131 register_sysctl_table(powersave_nap_sysctl_root);
132
133 return 0;
134}
135__initcall(register_powersave_nap_sysctl);
136#endif
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_disable();
56 } else {
57 /*
58 * Go into low thread priority and possibly
59 * low power mode.
60 */
61 HMT_low();
62 HMT_very_low();
63 }
64
65 HMT_medium();
66 ppc64_runlatch_on();
67}
68
69int powersave_nap;
70
71#ifdef CONFIG_PPC_970_NAP
72void power4_idle(void)
73{
74 if (!cpu_has_feature(CPU_FTR_CAN_NAP))
75 return;
76
77 if (!powersave_nap)
78 return;
79
80 if (!prep_irq_for_idle())
81 return;
82
83 if (cpu_has_feature(CPU_FTR_ALTIVEC))
84 asm volatile(PPC_DSSALL " ; sync" ::: "memory");
85
86 power4_idle_nap();
87
88 /*
89 * power4_idle_nap returns with interrupts enabled (soft and hard).
90 * to our caller with interrupts enabled (soft and hard). Our caller
91 * can cope with either interrupts disabled or enabled upon return.
92 */
93}
94#endif
95
96#ifdef CONFIG_SYSCTL
97/*
98 * Register the sysctl to set/clear powersave_nap.
99 */
100static struct ctl_table powersave_nap_ctl_table[] = {
101 {
102 .procname = "powersave-nap",
103 .data = &powersave_nap,
104 .maxlen = sizeof(int),
105 .mode = 0644,
106 .proc_handler = proc_dointvec,
107 },
108};
109
110static int __init
111register_powersave_nap_sysctl(void)
112{
113 register_sysctl("kernel", powersave_nap_ctl_table);
114
115 return 0;
116}
117__initcall(register_powersave_nap_sysctl);
118#endif