// SPDX-License-Identifier: GPL-2.0
/*
 * Idle functions for s390.
 *
 * Copyright IBM Corp. 2014
 *
 * Author(s): Martin Schwidefsky <schwidefsky@de.ibm.com>
 */

#include <linux/kernel.h>
#include <linux/kernel_stat.h>
#include <linux/notifier.h>
#include <linux/init.h>
#include <linux/cpu.h>
#include <trace/events/power.h>
#include <asm/cpu_mf.h>
#include <asm/cputime.h>
#include <asm/idle.h>
#include <asm/nmi.h>
#include <asm/smp.h>

DEFINE_PER_CPU(struct s390_idle_data, s390_idle);

void account_idle_time_irq(void)
{
        struct s390_idle_data *idle = this_cpu_ptr(&s390_idle);
        unsigned long idle_time;

        idle_time = get_lowcore()->int_clock - idle->clock_idle_enter;

        /* Account time spent with enabled wait psw loaded as idle time. */
        __atomic64_add(idle_time, &idle->idle_time);
        __atomic64_add_const(1, &idle->idle_count);
        account_idle_time(cputime_to_nsecs(idle_time));
}

void noinstr arch_cpu_idle(void)
{
        struct s390_idle_data *idle = this_cpu_ptr(&s390_idle);
        unsigned long psw_mask;

        /* Wait for external, I/O or machine check interrupt. */
        psw_mask = PSW_KERNEL_BITS | PSW_MASK_WAIT |
                   PSW_MASK_IO | PSW_MASK_EXT | PSW_MASK_MCHECK;
        clear_cpu_flag(CIF_NOHZ_DELAY);
        set_cpu_flag(CIF_ENABLED_WAIT);
        if (smp_cpu_mtid)
                stcctm(MT_DIAG, smp_cpu_mtid, (u64 *)&idle->mt_cycles_enter);
        idle->clock_idle_enter = get_tod_clock_fast();
        idle->timer_idle_enter = get_cpu_timer();
        bpon();
        __load_psw_mask(psw_mask);
}

static ssize_t show_idle_count(struct device *dev,
                               struct device_attribute *attr, char *buf)
{
        struct s390_idle_data *idle = &per_cpu(s390_idle, dev->id);

        return sysfs_emit(buf, "%lu\n", READ_ONCE(idle->idle_count));
}
DEVICE_ATTR(idle_count, 0444, show_idle_count, NULL);

static ssize_t show_idle_time(struct device *dev,
                              struct device_attribute *attr, char *buf)
{
        struct s390_idle_data *idle = &per_cpu(s390_idle, dev->id);

        return sysfs_emit(buf, "%lu\n", READ_ONCE(idle->idle_time) >> 12);
}
DEVICE_ATTR(idle_time_us, 0444, show_idle_time, NULL);

void arch_cpu_idle_enter(void)
{
}

void arch_cpu_idle_exit(void)
{
}

void __noreturn arch_cpu_idle_dead(void)
{
        cpu_die();
}