1// SPDX-License-Identifier: GPL-2.0
2/*
3 * Idle functions for s390.
4 *
5 * Copyright IBM Corp. 2014
6 *
7 * Author(s): Martin Schwidefsky <schwidefsky@de.ibm.com>
8 */
9
10#include <linux/kernel.h>
11#include <linux/kernel_stat.h>
12#include <linux/notifier.h>
13#include <linux/init.h>
14#include <linux/cpu.h>
15#include <trace/events/power.h>
16#include <asm/cpu_mf.h>
17#include <asm/cputime.h>
18#include <asm/nmi.h>
19#include <asm/smp.h>
20#include "entry.h"
21
22static DEFINE_PER_CPU(struct s390_idle_data, s390_idle);
23
24void account_idle_time_irq(void)
25{
26	struct s390_idle_data *idle = this_cpu_ptr(&s390_idle);
27	unsigned long idle_time;
28	u64 cycles_new[8];
29	int i;
30
31	if (smp_cpu_mtid) {
32		stcctm(MT_DIAG, smp_cpu_mtid, cycles_new);
33		for (i = 0; i < smp_cpu_mtid; i++)
34			this_cpu_add(mt_cycles[i], cycles_new[i] - idle->mt_cycles_enter[i]);
35	}
36
37	idle_time = S390_lowcore.int_clock - idle->clock_idle_enter;
38
39	S390_lowcore.steal_timer += idle->clock_idle_enter - S390_lowcore.last_update_clock;
40	S390_lowcore.last_update_clock = S390_lowcore.int_clock;
41
42	S390_lowcore.system_timer += S390_lowcore.last_update_timer - idle->timer_idle_enter;
43	S390_lowcore.last_update_timer = S390_lowcore.sys_enter_timer;
44
45	/* Account time spent with enabled wait psw loaded as idle time. */
46	WRITE_ONCE(idle->idle_time, READ_ONCE(idle->idle_time) + idle_time);
47	WRITE_ONCE(idle->idle_count, READ_ONCE(idle->idle_count) + 1);
48	account_idle_time(cputime_to_nsecs(idle_time));
49}
50
51void noinstr arch_cpu_idle(void)
52{
53	struct s390_idle_data *idle = this_cpu_ptr(&s390_idle);
54	unsigned long psw_mask;
55
56	/* Wait for external, I/O or machine check interrupt. */
57	psw_mask = PSW_KERNEL_BITS | PSW_MASK_WAIT |
58		   PSW_MASK_IO | PSW_MASK_EXT | PSW_MASK_MCHECK;
59	clear_cpu_flag(CIF_NOHZ_DELAY);
60	set_cpu_flag(CIF_ENABLED_WAIT);
61	if (smp_cpu_mtid)
62		stcctm(MT_DIAG, smp_cpu_mtid, (u64 *)&idle->mt_cycles_enter);
63	idle->clock_idle_enter = get_tod_clock_fast();
64	idle->timer_idle_enter = get_cpu_timer();
65	bpon();
66	__load_psw_mask(psw_mask);
67}
68
69static ssize_t show_idle_count(struct device *dev,
70			       struct device_attribute *attr, char *buf)
71{
72	struct s390_idle_data *idle = &per_cpu(s390_idle, dev->id);
73
74	return sysfs_emit(buf, "%lu\n", READ_ONCE(idle->idle_count));
75}
76DEVICE_ATTR(idle_count, 0444, show_idle_count, NULL);
77
78static ssize_t show_idle_time(struct device *dev,
79			      struct device_attribute *attr, char *buf)
80{
81	struct s390_idle_data *idle = &per_cpu(s390_idle, dev->id);
82
83	return sysfs_emit(buf, "%lu\n", READ_ONCE(idle->idle_time) >> 12);
84}
85DEVICE_ATTR(idle_time_us, 0444, show_idle_time, NULL);
86
87void arch_cpu_idle_enter(void)
88{
89}
90
91void arch_cpu_idle_exit(void)
92{
93}
94
95void __noreturn arch_cpu_idle_dead(void)
96{
97	cpu_die();
98}
99