// SPDX-License-Identifier: GPL-2.0-or-later
/*
 * processor_driver.c - ACPI Processor Driver
 *
 *  Copyright (C) 2001, 2002 Andy Grover <andrew.grover@intel.com>
 *  Copyright (C) 2001, 2002 Paul Diefenbaugh <paul.s.diefenbaugh@intel.com>
 *  Copyright (C) 2004       Dominik Brodowski <linux@brodo.de>
 *  Copyright (C) 2004  Anil S Keshavamurthy <anil.s.keshavamurthy@intel.com>
 *                      - Added processor hotplug support
 *  Copyright (C) 2013, Intel Corporation
 *                      Rafael J. Wysocki <rafael.j.wysocki@intel.com>
 */

#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/init.h>
#include <linux/cpufreq.h>
#include <linux/cpu.h>
#include <linux/cpuidle.h>
#include <linux/slab.h>
#include <linux/acpi.h>

#include <acpi/processor.h>

#include "internal.h"

#define ACPI_PROCESSOR_NOTIFY_PERFORMANCE 0x80
#define ACPI_PROCESSOR_NOTIFY_POWER     0x81
#define ACPI_PROCESSOR_NOTIFY_THROTTLING        0x82
#define ACPI_PROCESSOR_NOTIFY_HIGEST_PERF_CHANGED       0x85

MODULE_AUTHOR("Paul Diefenbaugh");
MODULE_DESCRIPTION("ACPI Processor Driver");
MODULE_LICENSE("GPL");

static int acpi_processor_stop(struct device *dev);

static const struct acpi_device_id processor_device_ids[] = {
        {ACPI_PROCESSOR_OBJECT_HID, 0},
        {ACPI_PROCESSOR_DEVICE_HID, 0},
        {"", 0},
};
MODULE_DEVICE_TABLE(acpi, processor_device_ids);

static struct device_driver acpi_processor_driver = {
        .name = "processor",
        .bus = &cpu_subsys,
        .acpi_match_table = processor_device_ids,
        .remove = acpi_processor_stop,
};

static void acpi_processor_notify(acpi_handle handle, u32 event, void *data)
{
        struct acpi_device *device = data;
        struct acpi_processor *pr;
        int saved;

        if (device->handle != handle)
                return;

        pr = acpi_driver_data(device);
        if (!pr)
                return;

        switch (event) {
        case ACPI_PROCESSOR_NOTIFY_PERFORMANCE:
                saved = pr->performance_platform_limit;
                acpi_processor_ppc_has_changed(pr, 1);
                if (saved == pr->performance_platform_limit)
                        break;
                acpi_bus_generate_netlink_event(device->pnp.device_class,
                                                  dev_name(&device->dev), event,
                                                  pr->performance_platform_limit);
                break;
        case ACPI_PROCESSOR_NOTIFY_POWER:
                acpi_processor_power_state_has_changed(pr);
                acpi_bus_generate_netlink_event(device->pnp.device_class,
                                                  dev_name(&device->dev), event, 0);
                break;
        case ACPI_PROCESSOR_NOTIFY_THROTTLING:
                acpi_processor_tstate_has_changed(pr);
                acpi_bus_generate_netlink_event(device->pnp.device_class,
                                                  dev_name(&device->dev), event, 0);
                break;
        case ACPI_PROCESSOR_NOTIFY_HIGEST_PERF_CHANGED:
                cpufreq_update_limits(pr->id);
                acpi_bus_generate_netlink_event(device->pnp.device_class,
                                                  dev_name(&device->dev), event, 0);
                break;
        default:
                acpi_handle_debug(handle, "Unsupported event [0x%x]\n", event);
                break;
        }

        return;
}

static int __acpi_processor_start(struct acpi_device *device);

static int acpi_soft_cpu_online(unsigned int cpu)
{
        struct acpi_processor *pr = per_cpu(processors, cpu);
        struct acpi_device *device;

        if (!pr)
                return 0;

        device = acpi_fetch_acpi_dev(pr->handle);
        if (!device)
                return 0;

        /*
         * CPU got physically hotplugged and onlined for the first time:
         * Initialize missing things.
         */
        if (!pr->flags.previously_online) {
                int ret;

                ret = __acpi_processor_start(device);
                WARN(ret, "Failed to start CPU: %d\n", pr->id);
        } else {
                /* Normal CPU soft online event. */
                acpi_processor_ppc_has_changed(pr, 0);
                acpi_processor_hotplug(pr);
                acpi_processor_reevaluate_tstate(pr, false);
                acpi_processor_tstate_has_changed(pr);
        }
        return 0;
}

static int acpi_soft_cpu_dead(unsigned int cpu)
{
        struct acpi_processor *pr = per_cpu(processors, cpu);

        if (!pr || !acpi_fetch_acpi_dev(pr->handle))
                return 0;

        acpi_processor_reevaluate_tstate(pr, true);
        return 0;
}

#ifdef CONFIG_ACPI_CPU_FREQ_PSS
static void acpi_pss_perf_init(struct acpi_processor *pr)
{
        acpi_processor_ppc_has_changed(pr, 0);

        acpi_processor_get_throttling_info(pr);

        if (pr->flags.throttling)
                pr->flags.limit = 1;
}
#else
static inline void acpi_pss_perf_init(struct acpi_processor *pr) {}
#endif /* CONFIG_ACPI_CPU_FREQ_PSS */

static int __acpi_processor_start(struct acpi_device *device)
{
        struct acpi_processor *pr = acpi_driver_data(device);
        acpi_status status;
        int result = 0;

        if (!pr)
                return -ENODEV;

        result = acpi_cppc_processor_probe(pr);
        if (result && !IS_ENABLED(CONFIG_ACPI_CPU_FREQ_PSS))
                dev_dbg(&device->dev, "CPPC data invalid or not present\n");

        acpi_processor_power_init(pr);

        acpi_pss_perf_init(pr);

        result = acpi_processor_thermal_init(pr, device);
        if (result)
                goto err_power_exit;

        status = acpi_install_notify_handler(device->handle, ACPI_DEVICE_NOTIFY,
                                             acpi_processor_notify, device);
        if (!ACPI_SUCCESS(status)) {
                result = -ENODEV;
                goto err_thermal_exit;
        }
        pr->flags.previously_online = 1;

        return 0;

err_thermal_exit:
        acpi_processor_thermal_exit(pr, device);
err_power_exit:
        acpi_processor_power_exit(pr);
        return result;
}

static int acpi_processor_stop(struct device *dev)
{
        struct acpi_device *device = ACPI_COMPANION(dev);
        struct acpi_processor *pr;

        if (!device)
                return 0;

        acpi_remove_notify_handler(device->handle, ACPI_DEVICE_NOTIFY,
                                   acpi_processor_notify);

        pr = acpi_driver_data(device);
        if (!pr)
                return 0;
        acpi_processor_power_exit(pr);

        acpi_cppc_processor_exit(pr);

        acpi_processor_thermal_exit(pr, device);

        return 0;
}

bool acpi_processor_cpufreq_init;

static int acpi_processor_notifier(struct notifier_block *nb,
                                   unsigned long event, void *data)
{
        struct cpufreq_policy *policy = data;

        if (event == CPUFREQ_CREATE_POLICY) {
                acpi_thermal_cpufreq_init(policy);
                acpi_processor_ppc_init(policy);
        } else if (event == CPUFREQ_REMOVE_POLICY) {
                acpi_processor_ppc_exit(policy);
                acpi_thermal_cpufreq_exit(policy);
        }

        return 0;
}

static struct notifier_block acpi_processor_notifier_block = {
        .notifier_call = acpi_processor_notifier,
};

void __weak acpi_processor_init_invariance_cppc(void)
{ }

/*
 * We keep the driver loaded even when ACPI is not running.
 * This is needed for the powernow-k8 driver, that works even without
 * ACPI, but needs symbols from this driver
 */
static enum cpuhp_state hp_online;
static int __init acpi_processor_driver_init(void)
{
        int result = 0;

        if (acpi_disabled)
                return 0;

        if (!cpufreq_register_notifier(&acpi_processor_notifier_block,
                                       CPUFREQ_POLICY_NOTIFIER)) {
                acpi_processor_cpufreq_init = true;
                acpi_processor_ignore_ppc_init();
        }

        acpi_processor_register_idle_driver();

        result = driver_register(&acpi_processor_driver);
        if (result < 0)
                goto unregister_idle_drv;

        result = cpuhp_setup_state(CPUHP_AP_ONLINE_DYN,
                                   "acpi/cpu-drv:online",
                                   acpi_soft_cpu_online, NULL);
        if (result < 0)
                goto err;
        hp_online = result;
        cpuhp_setup_state_nocalls(CPUHP_ACPI_CPUDRV_DEAD, "acpi/cpu-drv:dead",
                                  NULL, acpi_soft_cpu_dead);

        acpi_processor_throttling_init();

        /*
         * Frequency invariance calculations on AMD platforms can't be run until
         * after acpi_cppc_processor_probe() has been called for all online CPUs
         */
        acpi_processor_init_invariance_cppc();

        acpi_idle_rescan_dead_smt_siblings();

        return 0;

err:
        driver_unregister(&acpi_processor_driver);

unregister_idle_drv:
        acpi_processor_unregister_idle_driver();

        return result;
}

static void __exit acpi_processor_driver_exit(void)
{
        if (acpi_disabled)
                return;

        if (acpi_processor_cpufreq_init) {
                cpufreq_unregister_notifier(&acpi_processor_notifier_block,
                                            CPUFREQ_POLICY_NOTIFIER);
                acpi_processor_cpufreq_init = false;
        }

        cpuhp_remove_state_nocalls(hp_online);
        cpuhp_remove_state_nocalls(CPUHP_ACPI_CPUDRV_DEAD);
        driver_unregister(&acpi_processor_driver);
        acpi_processor_unregister_idle_driver();
}

module_init(acpi_processor_driver_init);
module_exit(acpi_processor_driver_exit);

MODULE_ALIAS("processor");