// SPDX-License-Identifier: GPL-2.0-only
/*
 * CPU kernel entry/exit control
 *
 * Copyright (C) 2013 ARM Ltd.
 */

#include <linux/acpi.h>
#include <linux/cache.h>
#include <linux/errno.h>
#include <linux/of.h>
#include <linux/string.h>
#include <asm/acpi.h>
#include <asm/cpu_ops.h>
#include <asm/smp_plat.h>

extern const struct cpu_operations smp_spin_table_ops;
#ifdef CONFIG_ARM64_ACPI_PARKING_PROTOCOL
extern const struct cpu_operations acpi_parking_protocol_ops;
#endif
extern const struct cpu_operations cpu_psci_ops;

static const struct cpu_operations *cpu_ops[NR_CPUS] __ro_after_init;

static const struct cpu_operations *const dt_supported_cpu_ops[] __initconst = {
        &smp_spin_table_ops,
        &cpu_psci_ops,
        NULL,
};

static const struct cpu_operations *const acpi_supported_cpu_ops[] __initconst = {
#ifdef CONFIG_ARM64_ACPI_PARKING_PROTOCOL
        &acpi_parking_protocol_ops,
#endif
        &cpu_psci_ops,
        NULL,
};

static const struct cpu_operations * __init cpu_get_ops(const char *name)
{
        const struct cpu_operations *const *ops;

        ops = acpi_disabled ? dt_supported_cpu_ops : acpi_supported_cpu_ops;

        while (*ops) {
                if (!strcmp(name, (*ops)->name))
                        return *ops;

                ops++;
        }

        return NULL;
}

static const char *__init cpu_read_enable_method(int cpu)
{
        const char *enable_method;

        if (acpi_disabled) {
                struct device_node *dn = of_get_cpu_node(cpu, NULL);

                if (!dn) {
                        if (!cpu)
                                pr_err("Failed to find device node for boot cpu\n");
                        return NULL;
                }

                enable_method = of_get_property(dn, "enable-method", NULL);
                if (!enable_method) {
                        /*
                         * The boot CPU may not have an enable method (e.g.
                         * when spin-table is used for secondaries).
                         * Don't warn spuriously.
                         */
                        if (cpu != 0)
                                pr_err("%pOF: missing enable-method property\n",
                                        dn);
                }
                of_node_put(dn);
        } else {
                enable_method = acpi_get_enable_method(cpu);
                if (!enable_method) {
                        /*
                         * In ACPI systems the boot CPU does not require
                         * checking the enable method since for some
                         * boot protocol (ie parking protocol) it need not
                         * be initialized. Don't warn spuriously.
                         */
                        if (cpu != 0)
                                pr_err("Unsupported ACPI enable-method\n");
                }
        }

        return enable_method;
}
/*
 * Read a cpu's enable method and record it in cpu_ops.
 */
int __init init_cpu_ops(int cpu)
{
        const char *enable_method = cpu_read_enable_method(cpu);

        if (!enable_method)
                return -ENODEV;

        cpu_ops[cpu] = cpu_get_ops(enable_method);
        if (!cpu_ops[cpu]) {
                pr_warn("Unsupported enable-method: %s\n", enable_method);
                return -EOPNOTSUPP;
        }

        return 0;
}

const struct cpu_operations *get_cpu_ops(int cpu)
{
        return cpu_ops[cpu];
}