// SPDX-License-Identifier: GPL-2.0-only
/*
 * ARM64 CPU idle arch support
 *
 * Copyright (C) 2014 ARM Ltd.
 * Author: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>
 */

#include <linux/acpi.h>
#include <linux/cpuidle.h>
#include <linux/cpu_pm.h>
#include <linux/psci.h>
#include <acpi/processor.h>

#define ARM64_LPI_IS_RETENTION_STATE(arch_flags) (!(arch_flags))

static int psci_acpi_cpu_init_idle(unsigned int cpu)
{
        int i, count;
        struct acpi_lpi_state *lpi;
        struct acpi_processor *pr = per_cpu(processors, cpu);

        if (unlikely(!pr || !pr->flags.has_lpi))
                return -EINVAL;

        /*
         * If the PSCI cpu_suspend function hook has not been initialized
         * idle states must not be enabled, so bail out
         */
        if (!psci_ops.cpu_suspend)
                return -EOPNOTSUPP;

        count = pr->power.count - 1;
        if (count <= 0)
                return -ENODEV;

        for (i = 0; i < count; i++) {
                u32 state;

                lpi = &pr->power.lpi_states[i + 1];
                /*
                 * Only bits[31:0] represent a PSCI power_state while
                 * bits[63:32] must be 0x0 as per ARM ACPI FFH Specification
                 */
                state = lpi->address;
                if (!psci_power_state_is_valid(state)) {
                        pr_warn("Invalid PSCI power state %#x\n", state);
                        return -EINVAL;
                }
        }

        return 0;
}

int acpi_processor_ffh_lpi_probe(unsigned int cpu)
{
        return psci_acpi_cpu_init_idle(cpu);
}

__cpuidle int acpi_processor_ffh_lpi_enter(struct acpi_lpi_state *lpi)
{
        u32 state = lpi->address;

        if (ARM64_LPI_IS_RETENTION_STATE(lpi->arch_flags))
                return CPU_PM_CPU_IDLE_ENTER_RETENTION_PARAM_RCU(psci_cpu_suspend_enter,
                                                lpi->index, state);
        else
                return CPU_PM_CPU_IDLE_ENTER_PARAM_RCU(psci_cpu_suspend_enter,
                                             lpi->index, state);
}