// SPDX-License-Identifier: GPL-2.0-only
/*
 *
 * Copyright (C) 2013 ARM Limited
 *
 * Author: Will Deacon <will.deacon@arm.com>
 */

#define pr_fmt(fmt) "psci: " fmt

#include <linux/init.h>
#include <linux/of.h>
#include <linux/smp.h>
#include <linux/delay.h>
#include <linux/psci.h>
#include <linux/mm.h>

#include <uapi/linux/psci.h>

#include <asm/cpu_ops.h>
#include <asm/errno.h>
#include <asm/smp_plat.h>

static int __init cpu_psci_cpu_init(unsigned int cpu)
{
        return 0;
}

static int __init cpu_psci_cpu_prepare(unsigned int cpu)
{
        if (!psci_ops.cpu_on) {
                pr_err("no cpu_on method, not booting CPU%d\n", cpu);
                return -ENODEV;
        }

        return 0;
}

static int cpu_psci_cpu_boot(unsigned int cpu)
{
        phys_addr_t pa_secondary_entry = __pa_symbol(secondary_entry);
        int err = psci_ops.cpu_on(cpu_logical_map(cpu), pa_secondary_entry);
        if (err && err != -EPERM)
                pr_err("failed to boot CPU%d (%d)\n", cpu, err);

        return err;
}

#ifdef CONFIG_HOTPLUG_CPU
static bool cpu_psci_cpu_can_disable(unsigned int cpu)
{
        return !psci_tos_resident_on(cpu);
}

static int cpu_psci_cpu_disable(unsigned int cpu)
{
        /* Fail early if we don't have CPU_OFF support */
        if (!psci_ops.cpu_off)
                return -EOPNOTSUPP;

        /* Trusted OS will deny CPU_OFF */
        if (psci_tos_resident_on(cpu))
                return -EPERM;

        return 0;
}

static void cpu_psci_cpu_die(unsigned int cpu)
{
        /*
         * There are no known implementations of PSCI actually using the
         * power state field, pass a sensible default for now.
         */
        u32 state = PSCI_POWER_STATE_TYPE_POWER_DOWN <<
                    PSCI_0_2_POWER_STATE_TYPE_SHIFT;

        psci_ops.cpu_off(state);
}

static int cpu_psci_cpu_kill(unsigned int cpu)
{
        int err;
        unsigned long start, end;

        if (!psci_ops.affinity_info)
                return 0;
        /*
         * cpu_kill could race with cpu_die and we can
         * potentially end up declaring this cpu undead
         * while it is dying. So, try again a few times.
         */

        start = jiffies;
        end = start + msecs_to_jiffies(100);
        do {
                err = psci_ops.affinity_info(cpu_logical_map(cpu), 0);
                if (err == PSCI_0_2_AFFINITY_LEVEL_OFF) {
                        pr_info("CPU%d killed (polled %d ms)\n", cpu,
                                jiffies_to_msecs(jiffies - start));
                        return 0;
                }

                usleep_range(100, 1000);
        } while (time_before(jiffies, end));

        pr_warn("CPU%d may not have shut down cleanly (AFFINITY_INFO reports %d)\n",
                        cpu, err);
        return -ETIMEDOUT;
}
#endif

const struct cpu_operations cpu_psci_ops = {
        .name           = "psci",
        .cpu_init       = cpu_psci_cpu_init,
        .cpu_prepare    = cpu_psci_cpu_prepare,
        .cpu_boot       = cpu_psci_cpu_boot,
#ifdef CONFIG_HOTPLUG_CPU
        .cpu_can_disable = cpu_psci_cpu_can_disable,
        .cpu_disable    = cpu_psci_cpu_disable,
        .cpu_die        = cpu_psci_cpu_die,
        .cpu_kill       = cpu_psci_cpu_kill,
#endif
};