// SPDX-License-Identifier: GPL-2.0-or-later
/*
 * Idle daemon for PowerPC.  Idle daemon will handle any action
 * that needs to be taken when the system becomes idle.
 *
 * Originally written by Cort Dougan (cort@cs.nmt.edu).
 * Subsequent 32-bit hacking by Tom Rini, Armin Kuster,
 * Paul Mackerras and others.
 *
 * iSeries supported added by Mike Corrigan <mikejc@us.ibm.com>
 *
 * Additional shared processor, SMT, and firmware support
 *    Copyright (c) 2003 Dave Engebretsen <engebret@us.ibm.com>
 *
 * 32-bit and 64-bit versions merged by Paul Mackerras <paulus@samba.org>
 */

#include <linux/sched.h>
#include <linux/kernel.h>
#include <linux/smp.h>
#include <linux/cpu.h>
#include <linux/sysctl.h>
#include <linux/tick.h>

#include <asm/processor.h>
#include <asm/cputable.h>
#include <asm/time.h>
#include <asm/machdep.h>
#include <asm/runlatch.h>
#include <asm/smp.h>


unsigned long cpuidle_disable = IDLE_NO_OVERRIDE;
EXPORT_SYMBOL(cpuidle_disable);

static int __init powersave_off(char *arg)
{
        ppc_md.power_save = NULL;
        cpuidle_disable = IDLE_POWERSAVE_OFF;
        return 1;
}
__setup("powersave=off", powersave_off);

void arch_cpu_idle(void)
{
        ppc64_runlatch_off();

        if (ppc_md.power_save) {
                ppc_md.power_save();
                /*
                 * Some power_save functions return with
                 * interrupts enabled, some don't.
                 */
                if (!irqs_disabled())
                        raw_local_irq_disable();
        } else {
                /*
                 * Go into low thread priority and possibly
                 * low power mode.
                 */
                HMT_low();
                HMT_very_low();
        }

        HMT_medium();
        ppc64_runlatch_on();
}

int powersave_nap;

#ifdef CONFIG_PPC_970_NAP
void power4_idle(void)
{
        if (!cpu_has_feature(CPU_FTR_CAN_NAP))
                return;

        if (!powersave_nap)
                return;

        if (!prep_irq_for_idle())
                return;

        if (cpu_has_feature(CPU_FTR_ALTIVEC))
                asm volatile(PPC_DSSALL " ; sync" ::: "memory");

        power4_idle_nap();

        /*
         * power4_idle_nap returns with interrupts enabled (soft and hard).
         * to our caller with interrupts enabled (soft and hard). Our caller
         * can cope with either interrupts disabled or enabled upon return.
         */
}
#endif

#ifdef CONFIG_SYSCTL
/*
 * Register the sysctl to set/clear powersave_nap.
 */
static const struct ctl_table powersave_nap_ctl_table[] = {
        {
                .procname       = "powersave-nap",
                .data           = &powersave_nap,
                .maxlen         = sizeof(int),
                .mode           = 0644,
                .proc_handler   = proc_dointvec,
        },
};

static int __init
register_powersave_nap_sysctl(void)
{
        register_sysctl("kernel", powersave_nap_ctl_table);

        return 0;
}
__initcall(register_powersave_nap_sysctl);
#endif