1 // SPDX-License-Identifier: GPL-2.0
3 * Idle functions for s390.
5 * Copyright IBM Corp. 2014
7 * Author(s): Martin Schwidefsky <schwidefsky@de.ibm.com>
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 <linux/sched/cputime.h>
16 #include <trace/events/power.h>
17 #include <asm/cpu_mf.h>
22 static DEFINE_PER_CPU(struct s390_idle_data, s390_idle);
24 void account_idle_time_irq(void)
26 struct s390_idle_data *idle = this_cpu_ptr(&s390_idle);
30 clear_cpu_flag(CIF_ENABLED_WAIT);
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]);
37 idle->clock_idle_exit = S390_lowcore.int_clock;
38 idle->timer_idle_exit = S390_lowcore.sys_enter_timer;
40 S390_lowcore.steal_timer += idle->clock_idle_enter - S390_lowcore.last_update_clock;
41 S390_lowcore.last_update_clock = idle->clock_idle_exit;
43 S390_lowcore.system_timer += S390_lowcore.last_update_timer - idle->timer_idle_enter;
44 S390_lowcore.last_update_timer = idle->timer_idle_exit;
47 void arch_cpu_idle(void)
49 struct s390_idle_data *idle = this_cpu_ptr(&s390_idle);
50 unsigned long idle_time;
51 unsigned long psw_mask;
53 /* Wait for external, I/O or machine check interrupt. */
54 psw_mask = PSW_KERNEL_BITS | PSW_MASK_WAIT | PSW_MASK_DAT |
55 PSW_MASK_IO | PSW_MASK_EXT | PSW_MASK_MCHECK;
56 clear_cpu_flag(CIF_NOHZ_DELAY);
58 /* psw_idle() returns with interrupts disabled. */
59 psw_idle(idle, psw_mask);
61 /* Account time spent with enabled wait psw loaded as idle time. */
62 raw_write_seqcount_begin(&idle->seqcount);
63 idle_time = idle->clock_idle_exit - idle->clock_idle_enter;
64 idle->clock_idle_enter = idle->clock_idle_exit = 0ULL;
65 idle->idle_time += idle_time;
67 account_idle_time(cputime_to_nsecs(idle_time));
68 raw_write_seqcount_end(&idle->seqcount);
69 raw_local_irq_enable();
72 static ssize_t show_idle_count(struct device *dev,
73 struct device_attribute *attr, char *buf)
75 struct s390_idle_data *idle = &per_cpu(s390_idle, dev->id);
76 unsigned long idle_count;
80 seq = read_seqcount_begin(&idle->seqcount);
81 idle_count = READ_ONCE(idle->idle_count);
82 if (READ_ONCE(idle->clock_idle_enter))
84 } while (read_seqcount_retry(&idle->seqcount, seq));
85 return sprintf(buf, "%lu\n", idle_count);
87 DEVICE_ATTR(idle_count, 0444, show_idle_count, NULL);
89 static ssize_t show_idle_time(struct device *dev,
90 struct device_attribute *attr, char *buf)
92 unsigned long now, idle_time, idle_enter, idle_exit, in_idle;
93 struct s390_idle_data *idle = &per_cpu(s390_idle, dev->id);
97 seq = read_seqcount_begin(&idle->seqcount);
98 idle_time = READ_ONCE(idle->idle_time);
99 idle_enter = READ_ONCE(idle->clock_idle_enter);
100 idle_exit = READ_ONCE(idle->clock_idle_exit);
101 } while (read_seqcount_retry(&idle->seqcount, seq));
103 now = get_tod_clock();
106 in_idle = idle_exit - idle_enter;
107 } else if (now > idle_enter) {
108 in_idle = now - idle_enter;
111 idle_time += in_idle;
112 return sprintf(buf, "%lu\n", idle_time >> 12);
114 DEVICE_ATTR(idle_time_us, 0444, show_idle_time, NULL);
116 u64 arch_cpu_idle_time(int cpu)
118 struct s390_idle_data *idle = &per_cpu(s390_idle, cpu);
119 unsigned long now, idle_enter, idle_exit, in_idle;
123 seq = read_seqcount_begin(&idle->seqcount);
124 idle_enter = READ_ONCE(idle->clock_idle_enter);
125 idle_exit = READ_ONCE(idle->clock_idle_exit);
126 } while (read_seqcount_retry(&idle->seqcount, seq));
128 now = get_tod_clock();
131 in_idle = idle_exit - idle_enter;
132 } else if (now > idle_enter) {
133 in_idle = now - idle_enter;
136 return cputime_to_nsecs(in_idle);
139 void arch_cpu_idle_enter(void)
143 void arch_cpu_idle_exit(void)
147 void arch_cpu_idle_dead(void)