/*
 * drivers/acpi/device_pm.c - ACPI device power management routines.
 *
 * Copyright (C) 2012, Intel Corp.
 * Author: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
 *
 * ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 *
 *  This program is free software; you can redistribute it and/or modify
 *  it under the terms of the GNU General Public License version 2 as published
 *  by the Free Software Foundation.
 *
 *  This program is distributed in the hope that it will be useful, but
 *  WITHOUT ANY WARRANTY; without even the implied warranty of
 *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 *  General Public License for more details.
 *
 * ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 */

#include <linux/acpi.h>
#include <linux/export.h>
#include <linux/mutex.h>
#include <linux/pm_qos.h>
#include <linux/pm_domain.h>
#include <linux/pm_runtime.h>

#include "internal.h"

#define _COMPONENT      ACPI_POWER_COMPONENT
ACPI_MODULE_NAME("device_pm");

/**
 * acpi_power_state_string - String representation of ACPI device power state.
 * @state: ACPI device power state to return the string representation of.
 */
const char *acpi_power_state_string(int state)
{
        switch (state) {
        case ACPI_STATE_D0:
                return "D0";
        case ACPI_STATE_D1:
                return "D1";
        case ACPI_STATE_D2:
                return "D2";
        case ACPI_STATE_D3_HOT:
                return "D3hot";
        case ACPI_STATE_D3_COLD:
                return "D3cold";
        default:
                return "(unknown)";
        }
}

/**
 * acpi_device_get_power - Get power state of an ACPI device.
 * @device: Device to get the power state of.
 * @state: Place to store the power state of the device.
 *
 * This function does not update the device's power.state field, but it may
 * update its parent's power.state field (when the parent's power state is
 * unknown and the device's power state turns out to be D0).
 */
int acpi_device_get_power(struct acpi_device *device, int *state)
{
        int result = ACPI_STATE_UNKNOWN;

        if (!device || !state)
                return -EINVAL;

        if (!device->flags.power_manageable) {
                /* TBD: Non-recursive algorithm for walking up hierarchy. */
                *state = device->parent ?
                        device->parent->power.state : ACPI_STATE_D0;
                goto out;
        }

        /*
         * Get the device's power state from power resources settings and _PSC,
         * if available.
         */
        if (device->power.flags.power_resources) {
                int error = acpi_power_get_inferred_state(device, &result);
                if (error)
                        return error;
        }
        if (device->power.flags.explicit_get) {
                acpi_handle handle = device->handle;
                unsigned long long psc;
                acpi_status status;

                status = acpi_evaluate_integer(handle, "_PSC", NULL, &psc);
                if (ACPI_FAILURE(status))
                        return -ENODEV;

                /*
                 * The power resources settings may indicate a power state
                 * shallower than the actual power state of the device, because
                 * the same power resources may be referenced by other devices.
                 *
                 * For systems predating ACPI 4.0 we assume that D3hot is the
                 * deepest state that can be supported.
                 */
                if (psc > result && psc < ACPI_STATE_D3_COLD)
                        result = psc;
                else if (result == ACPI_STATE_UNKNOWN)
                        result = psc > ACPI_STATE_D2 ? ACPI_STATE_D3_HOT : psc;
        }

        /*
         * If we were unsure about the device parent's power state up to this
         * point, the fact that the device is in D0 implies that the parent has
         * to be in D0 too, except if ignore_parent is set.
         */
        if (!device->power.flags.ignore_parent && device->parent
            && device->parent->power.state == ACPI_STATE_UNKNOWN
            && result == ACPI_STATE_D0)
                device->parent->power.state = ACPI_STATE_D0;

        *state = result;

 out:
        ACPI_DEBUG_PRINT((ACPI_DB_INFO, "Device [%s] power state is %s\n",
                          device->pnp.bus_id, acpi_power_state_string(*state)));

        return 0;
}

static int acpi_dev_pm_explicit_set(struct acpi_device *adev, int state)
{
        if (adev->power.states[state].flags.explicit_set) {
                char method[5] = { '_', 'P', 'S', '0' + state, '\0' };
                acpi_status status;

                status = acpi_evaluate_object(adev->handle, method, NULL, NULL);
                if (ACPI_FAILURE(status))
                        return -ENODEV;
        }
        return 0;
}

/**
 * acpi_device_set_power - Set power state of an ACPI device.
 * @device: Device to set the power state of.
 * @state: New power state to set.
 *
 * Callers must ensure that the device is power manageable before using this
 * function.
 */
int acpi_device_set_power(struct acpi_device *device, int state)
{
        int target_state = state;
        int result = 0;

        if (!device || !device->flags.power_manageable
            || (state < ACPI_STATE_D0) || (state > ACPI_STATE_D3_COLD))
                return -EINVAL;

        /* Make sure this is a valid target state */

        if (state == device->power.state) {
                ACPI_DEBUG_PRINT((ACPI_DB_INFO, "Device [%s] already in %s\n",
                                  device->pnp.bus_id,
                                  acpi_power_state_string(state)));
                return 0;
        }

        if (state == ACPI_STATE_D3_COLD) {
                /*
                 * For transitions to D3cold we need to execute _PS3 and then
                 * possibly drop references to the power resources in use.
                 */
                state = ACPI_STATE_D3_HOT;
                /* If _PR3 is not available, use D3hot as the target state. */
                if (!device->power.states[ACPI_STATE_D3_COLD].flags.valid)
                        target_state = state;
        } else if (!device->power.states[state].flags.valid) {
                dev_warn(&device->dev, "Power state %s not supported\n",
                         acpi_power_state_string(state));
                return -ENODEV;
        }

        if (!device->power.flags.ignore_parent &&
            device->parent && (state < device->parent->power.state)) {
                dev_warn(&device->dev,
                         "Cannot transition to power state %s for parent in %s\n",
                         acpi_power_state_string(state),
                         acpi_power_state_string(device->parent->power.state));
                return -ENODEV;
        }

        /*
         * Transition Power
         * ----------------
         * In accordance with ACPI 6, _PSx is executed before manipulating power
         * resources, unless the target state is D0, in which case _PS0 is
         * supposed to be executed after turning the power resources on.
         */
        if (state > ACPI_STATE_D0) {
                /*
                 * According to ACPI 6, devices cannot go from lower-power
                 * (deeper) states to higher-power (shallower) states.
                 */
                if (state < device->power.state) {
                        dev_warn(&device->dev, "Cannot transition from %s to %s\n",
                                 acpi_power_state_string(device->power.state),
                                 acpi_power_state_string(state));
                        return -ENODEV;
                }

                result = acpi_dev_pm_explicit_set(device, state);
                if (result)
                        goto end;

                if (device->power.flags.power_resources)
                        result = acpi_power_transition(device, target_state);
        } else {
                if (device->power.flags.power_resources) {
                        result = acpi_power_transition(device, ACPI_STATE_D0);
                        if (result)
                                goto end;
                }
                result = acpi_dev_pm_explicit_set(device, ACPI_STATE_D0);
        }

 end:
        if (result) {
                dev_warn(&device->dev, "Failed to change power state to %s\n",
                         acpi_power_state_string(state));
        } else {
                device->power.state = target_state;
                ACPI_DEBUG_PRINT((ACPI_DB_INFO,
                                  "Device [%s] transitioned to %s\n",
                                  device->pnp.bus_id,
                                  acpi_power_state_string(state)));
        }

        return result;
}
EXPORT_SYMBOL(acpi_device_set_power);

int acpi_bus_set_power(acpi_handle handle, int state)
{
        struct acpi_device *device;
        int result;

        result = acpi_bus_get_device(handle, &device);
        if (result)
                return result;

        return acpi_device_set_power(device, state);
}
EXPORT_SYMBOL(acpi_bus_set_power);

int acpi_bus_init_power(struct acpi_device *device)
{
        int state;
        int result;

        if (!device)
                return -EINVAL;

        device->power.state = ACPI_STATE_UNKNOWN;
        if (!acpi_device_is_present(device))
                return -ENXIO;

        result = acpi_device_get_power(device, &state);
        if (result)
                return result;

        if (state < ACPI_STATE_D3_COLD && device->power.flags.power_resources) {
                /* Reference count the power resources. */
                result = acpi_power_on_resources(device, state);
                if (result)
                        return result;

                if (state == ACPI_STATE_D0) {
                        /*
                         * If _PSC is not present and the state inferred from
                         * power resources appears to be D0, it still may be
                         * necessary to execute _PS0 at this point, because
                         * another device using the same power resources may
                         * have been put into D0 previously and that's why we
                         * see D0 here.
                         */
                        result = acpi_dev_pm_explicit_set(device, state);
                        if (result)
                                return result;
                }
        } else if (state == ACPI_STATE_UNKNOWN) {
                /*
                 * No power resources and missing _PSC?  Cross fingers and make
                 * it D0 in hope that this is what the BIOS put the device into.
                 * [We tried to force D0 here by executing _PS0, but that broke
                 * Toshiba P870-303 in a nasty way.]
                 */
                state = ACPI_STATE_D0;
        }
        device->power.state = state;
        return 0;
}

/**
 * acpi_device_fix_up_power - Force device with missing _PSC into D0.
 * @device: Device object whose power state is to be fixed up.
 *
 * Devices without power resources and _PSC, but having _PS0 and _PS3 defined,
 * are assumed to be put into D0 by the BIOS.  However, in some cases that may
 * not be the case and this function should be used then.
 */
int acpi_device_fix_up_power(struct acpi_device *device)
{
        int ret = 0;

        if (!device->power.flags.power_resources
            && !device->power.flags.explicit_get
            && device->power.state == ACPI_STATE_D0)
                ret = acpi_dev_pm_explicit_set(device, ACPI_STATE_D0);

        return ret;
}
EXPORT_SYMBOL_GPL(acpi_device_fix_up_power);

int acpi_device_update_power(struct acpi_device *device, int *state_p)
{
        int state;
        int result;

        if (device->power.state == ACPI_STATE_UNKNOWN) {
                result = acpi_bus_init_power(device);
                if (!result && state_p)
                        *state_p = device->power.state;

                return result;
        }

        result = acpi_device_get_power(device, &state);
        if (result)
                return result;

        if (state == ACPI_STATE_UNKNOWN) {
                state = ACPI_STATE_D0;
                result = acpi_device_set_power(device, state);
                if (result)
                        return result;
        } else {
                if (device->power.flags.power_resources) {
                        /*
                         * We don't need to really switch the state, bu we need
                         * to update the power resources' reference counters.
                         */
                        result = acpi_power_transition(device, state);
                        if (result)
                                return result;
                }
                device->power.state = state;
        }
        if (state_p)
                *state_p = state;

        return 0;
}
EXPORT_SYMBOL_GPL(acpi_device_update_power);

int acpi_bus_update_power(acpi_handle handle, int *state_p)
{
        struct acpi_device *device;
        int result;

        result = acpi_bus_get_device(handle, &device);
        return result ? result : acpi_device_update_power(device, state_p);
}
EXPORT_SYMBOL_GPL(acpi_bus_update_power);

bool acpi_bus_power_manageable(acpi_handle handle)
{
        struct acpi_device *device;
        int result;

        result = acpi_bus_get_device(handle, &device);
        return result ? false : device->flags.power_manageable;
}
EXPORT_SYMBOL(acpi_bus_power_manageable);

#ifdef CONFIG_PM
static DEFINE_MUTEX(acpi_pm_notifier_lock);

static void acpi_pm_notify_handler(acpi_handle handle, u32 val, void *not_used)
{
        struct acpi_device *adev;

        if (val != ACPI_NOTIFY_DEVICE_WAKE)
                return;

        adev = acpi_bus_get_acpi_device(handle);
        if (!adev)
                return;

        mutex_lock(&acpi_pm_notifier_lock);

        if (adev->wakeup.flags.notifier_present) {
                __pm_wakeup_event(adev->wakeup.ws, 0);
                if (adev->wakeup.context.work.func)
                        queue_pm_work(&adev->wakeup.context.work);
        }

        mutex_unlock(&acpi_pm_notifier_lock);

        acpi_bus_put_acpi_device(adev);
}

/**
 * acpi_add_pm_notifier - Register PM notify handler for given ACPI device.
 * @adev: ACPI device to add the notify handler for.
 * @dev: Device to generate a wakeup event for while handling the notification.
 * @work_func: Work function to execute when handling the notification.
 *
 * NOTE: @adev need not be a run-wake or wakeup device to be a valid source of
 * PM wakeup events.  For example, wakeup events may be generated for bridges
 * if one of the devices below the bridge is signaling wakeup, even if the
 * bridge itself doesn't have a wakeup GPE associated with it.
 */
acpi_status acpi_add_pm_notifier(struct acpi_device *adev, struct device *dev,
                                 void (*work_func)(struct work_struct *work))
{
        acpi_status status = AE_ALREADY_EXISTS;

        if (!dev && !work_func)
                return AE_BAD_PARAMETER;

        mutex_lock(&acpi_pm_notifier_lock);

        if (adev->wakeup.flags.notifier_present)
                goto out;

        adev->wakeup.ws = wakeup_source_register(dev_name(&adev->dev));
        adev->wakeup.context.dev = dev;
        if (work_func)
                INIT_WORK(&adev->wakeup.context.work, work_func);

        status = acpi_install_notify_handler(adev->handle, ACPI_SYSTEM_NOTIFY,
                                             acpi_pm_notify_handler, NULL);
        if (ACPI_FAILURE(status))
                goto out;

        adev->wakeup.flags.notifier_present = true;

 out:
        mutex_unlock(&acpi_pm_notifier_lock);
        return status;
}

/**
 * acpi_remove_pm_notifier - Unregister PM notifier from given ACPI device.
 * @adev: ACPI device to remove the notifier from.
 */
acpi_status acpi_remove_pm_notifier(struct acpi_device *adev)
{
        acpi_status status = AE_BAD_PARAMETER;

        mutex_lock(&acpi_pm_notifier_lock);

        if (!adev->wakeup.flags.notifier_present)
                goto out;

        status = acpi_remove_notify_handler(adev->handle,
                                            ACPI_SYSTEM_NOTIFY,
                                            acpi_pm_notify_handler);
        if (ACPI_FAILURE(status))
                goto out;

        if (adev->wakeup.context.work.func) {
                cancel_work_sync(&adev->wakeup.context.work);
                adev->wakeup.context.work.func = NULL;
        }
        adev->wakeup.context.dev = NULL;
        wakeup_source_unregister(adev->wakeup.ws);

        adev->wakeup.flags.notifier_present = false;

 out:
        mutex_unlock(&acpi_pm_notifier_lock);
        return status;
}

bool acpi_bus_can_wakeup(acpi_handle handle)
{
        struct acpi_device *device;
        int result;

        result = acpi_bus_get_device(handle, &device);
        return result ? false : device->wakeup.flags.valid;
}
EXPORT_SYMBOL(acpi_bus_can_wakeup);

/**
 * acpi_dev_pm_get_state - Get preferred power state of ACPI device.
 * @dev: Device whose preferred target power state to return.
 * @adev: ACPI device node corresponding to @dev.
 * @target_state: System state to match the resultant device state.
 * @d_min_p: Location to store the highest power state available to the device.
 * @d_max_p: Location to store the lowest power state available to the device.
 *
 * Find the lowest power (highest number) and highest power (lowest number) ACPI
 * device power states that the device can be in while the system is in the
 * state represented by @target_state.  Store the integer numbers representing
 * those stats in the memory locations pointed to by @d_max_p and @d_min_p,
 * respectively.
 *
 * Callers must ensure that @dev and @adev are valid pointers and that @adev
 * actually corresponds to @dev before using this function.
 *
 * Returns 0 on success or -ENODATA when one of the ACPI methods fails or
 * returns a value that doesn't make sense.  The memory locations pointed to by
 * @d_max_p and @d_min_p are only modified on success.
 */
static int acpi_dev_pm_get_state(struct device *dev, struct acpi_device *adev,
                                 u32 target_state, int *d_min_p, int *d_max_p)
{
        char method[] = { '_', 'S', '0' + target_state, 'D', '\0' };
        acpi_handle handle = adev->handle;
        unsigned long long ret;
        int d_min, d_max;
        bool wakeup = false;
        acpi_status status;

        /*
         * If the system state is S0, the lowest power state the device can be
         * in is D3cold, unless the device has _S0W and is supposed to signal
         * wakeup, in which case the return value of _S0W has to be used as the
         * lowest power state available to the device.
         */
        d_min = ACPI_STATE_D0;
        d_max = ACPI_STATE_D3_COLD;

        /*
         * If present, _SxD methods return the minimum D-state (highest power
         * state) we can use for the corresponding S-states.  Otherwise, the
         * minimum D-state is D0 (ACPI 3.x).
         */
        if (target_state > ACPI_STATE_S0) {
                /*
                 * We rely on acpi_evaluate_integer() not clobbering the integer
                 * provided if AE_NOT_FOUND is returned.
                 */
                ret = d_min;
                status = acpi_evaluate_integer(handle, method, NULL, &ret);
                if ((ACPI_FAILURE(status) && status != AE_NOT_FOUND)
                    || ret > ACPI_STATE_D3_COLD)
                        return -ENODATA;

                /*
                 * We need to handle legacy systems where D3hot and D3cold are
                 * the same and 3 is returned in both cases, so fall back to
                 * D3cold if D3hot is not a valid state.
                 */
                if (!adev->power.states[ret].flags.valid) {
                        if (ret == ACPI_STATE_D3_HOT)
                                ret = ACPI_STATE_D3_COLD;
                        else
                                return -ENODATA;
                }
                d_min = ret;
                wakeup = device_may_wakeup(dev) && adev->wakeup.flags.valid
                        && adev->wakeup.sleep_state >= target_state;
        } else if (dev_pm_qos_flags(dev, PM_QOS_FLAG_REMOTE_WAKEUP) !=
                        PM_QOS_FLAGS_NONE) {
                wakeup = adev->wakeup.flags.valid;
        }

        /*
         * If _PRW says we can wake up the system from the target sleep state,
         * the D-state returned by _SxD is sufficient for that (we assume a
         * wakeup-aware driver if wake is set).  Still, if _SxW exists
         * (ACPI 3.x), it should return the maximum (lowest power) D-state that
         * can wake the system.  _S0W may be valid, too.
         */
        if (wakeup) {
                method[3] = 'W';
                status = acpi_evaluate_integer(handle, method, NULL, &ret);
                if (status == AE_NOT_FOUND) {
                        if (target_state > ACPI_STATE_S0)
                                d_max = d_min;
                } else if (ACPI_SUCCESS(status) && ret <= ACPI_STATE_D3_COLD) {
                        /* Fall back to D3cold if ret is not a valid state. */
                        if (!adev->power.states[ret].flags.valid)
                                ret = ACPI_STATE_D3_COLD;

                        d_max = ret > d_min ? ret : d_min;
                } else {
                        return -ENODATA;
                }
        }

        if (d_min_p)
                *d_min_p = d_min;

        if (d_max_p)
                *d_max_p = d_max;

        return 0;
}

/**
 * acpi_pm_device_sleep_state - Get preferred power state of ACPI device.
 * @dev: Device whose preferred target power state to return.
 * @d_min_p: Location to store the upper limit of the allowed states range.
 * @d_max_in: Deepest low-power state to take into consideration.
 * Return value: Preferred power state of the device on success, -ENODEV
 * if there's no 'struct acpi_device' for @dev, -EINVAL if @d_max_in is
 * incorrect, or -ENODATA on ACPI method failure.
 *
 * The caller must ensure that @dev is valid before using this function.
 */
int acpi_pm_device_sleep_state(struct device *dev, int *d_min_p, int d_max_in)
{
        struct acpi_device *adev;
        int ret, d_min, d_max;

        if (d_max_in < ACPI_STATE_D0 || d_max_in > ACPI_STATE_D3_COLD)
                return -EINVAL;

        if (d_max_in > ACPI_STATE_D2) {
                enum pm_qos_flags_status stat;

                stat = dev_pm_qos_flags(dev, PM_QOS_FLAG_NO_POWER_OFF);
                if (stat == PM_QOS_FLAGS_ALL)
                        d_max_in = ACPI_STATE_D2;
        }

        adev = ACPI_COMPANION(dev);
        if (!adev) {
                dev_dbg(dev, "ACPI companion missing in %s!\n", __func__);
                return -ENODEV;
        }

        ret = acpi_dev_pm_get_state(dev, adev, acpi_target_system_state(),
                                    &d_min, &d_max);
        if (ret)
                return ret;

        if (d_max_in < d_min)
                return -EINVAL;

        if (d_max > d_max_in) {
                for (d_max = d_max_in; d_max > d_min; d_max--) {
                        if (adev->power.states[d_max].flags.valid)
                                break;
                }
        }

        if (d_min_p)
                *d_min_p = d_min;

        return d_max;
}
EXPORT_SYMBOL(acpi_pm_device_sleep_state);

/**
 * acpi_pm_notify_work_func - ACPI devices wakeup notification work function.
 * @work: Work item to handle.
 */
static void acpi_pm_notify_work_func(struct work_struct *work)
{
        struct device *dev;

        dev = container_of(work, struct acpi_device_wakeup_context, work)->dev;
        if (dev) {
                pm_wakeup_event(dev, 0);
                pm_runtime_resume(dev);
        }
}

/**
 * acpi_device_wakeup - Enable/disable wakeup functionality for device.
 * @adev: ACPI device to enable/disable wakeup functionality for.
 * @target_state: State the system is transitioning into.
 * @enable: Whether to enable or disable the wakeup functionality.
 *
 * Enable/disable the GPE associated with @adev so that it can generate
 * wakeup signals for the device in response to external (remote) events and
 * enable/disable device wakeup power.
 *
 * Callers must ensure that @adev is a valid ACPI device node before executing
 * this function.
 */
static int acpi_device_wakeup(struct acpi_device *adev, u32 target_state,
                              bool enable)
{
        struct acpi_device_wakeup *wakeup = &adev->wakeup;

        if (enable) {
                acpi_status res;
                int error;

                error = acpi_enable_wakeup_device_power(adev, target_state);
                if (error)
                        return error;

                if (adev->wakeup.flags.enabled)
                        return 0;

                res = acpi_enable_gpe(wakeup->gpe_device, wakeup->gpe_number);
                if (ACPI_SUCCESS(res)) {
                        adev->wakeup.flags.enabled = 1;
                } else {
                        acpi_disable_wakeup_device_power(adev);
                        return -EIO;
                }
        } else {
                if (adev->wakeup.flags.enabled) {
                        acpi_disable_gpe(wakeup->gpe_device, wakeup->gpe_number);
                        adev->wakeup.flags.enabled = 0;
                }
                acpi_disable_wakeup_device_power(adev);
        }
        return 0;
}

/**
 * acpi_pm_device_run_wake - Enable/disable remote wakeup for given device.
 * @dev: Device to enable/disable the platform to wake up.
 * @enable: Whether to enable or disable the wakeup functionality.
 */
int acpi_pm_device_run_wake(struct device *phys_dev, bool enable)
{
        struct acpi_device *adev;

        if (!device_run_wake(phys_dev))
                return -EINVAL;

        adev = ACPI_COMPANION(phys_dev);
        if (!adev) {
                dev_dbg(phys_dev, "ACPI companion missing in %s!\n", __func__);
                return -ENODEV;
        }

        return acpi_device_wakeup(adev, ACPI_STATE_S0, enable);
}
EXPORT_SYMBOL(acpi_pm_device_run_wake);

#ifdef CONFIG_PM_SLEEP
/**
 * acpi_pm_device_sleep_wake - Enable or disable device to wake up the system.
 * @dev: Device to enable/desible to wake up the system from sleep states.
 * @enable: Whether to enable or disable @dev to wake up the system.
 */
int acpi_pm_device_sleep_wake(struct device *dev, bool enable)
{
        struct acpi_device *adev;
        int error;

        if (!device_can_wakeup(dev))
                return -EINVAL;

        adev = ACPI_COMPANION(dev);
        if (!adev) {
                dev_dbg(dev, "ACPI companion missing in %s!\n", __func__);
                return -ENODEV;
        }

        error = acpi_device_wakeup(adev, acpi_target_system_state(), enable);
        if (!error)
                dev_info(dev, "System wakeup %s by ACPI\n",
                                enable ? "enabled" : "disabled");

        return error;
}
#endif /* CONFIG_PM_SLEEP */

/**
 * acpi_dev_pm_low_power - Put ACPI device into a low-power state.
 * @dev: Device to put into a low-power state.
 * @adev: ACPI device node corresponding to @dev.
 * @system_state: System state to choose the device state for.
 */
static int acpi_dev_pm_low_power(struct device *dev, struct acpi_device *adev,
                                 u32 system_state)
{
        int ret, state;

        if (!acpi_device_power_manageable(adev))
                return 0;

        ret = acpi_dev_pm_get_state(dev, adev, system_state, NULL, &state);
        return ret ? ret : acpi_device_set_power(adev, state);
}

/**
 * acpi_dev_pm_full_power - Put ACPI device into the full-power state.
 * @adev: ACPI device node to put into the full-power state.
 */
static int acpi_dev_pm_full_power(struct acpi_device *adev)
{
        return acpi_device_power_manageable(adev) ?
                acpi_device_set_power(adev, ACPI_STATE_D0) : 0;
}

/**
 * acpi_dev_runtime_suspend - Put device into a low-power state using ACPI.
 * @dev: Device to put into a low-power state.
 *
 * Put the given device into a runtime low-power state using the standard ACPI
 * mechanism.  Set up remote wakeup if desired, choose the state to put the
 * device into (this checks if remote wakeup is expected to work too), and set
 * the power state of the device.
 */
int acpi_dev_runtime_suspend(struct device *dev)
{
        struct acpi_device *adev = ACPI_COMPANION(dev);
        bool remote_wakeup;
        int error;

        if (!adev)
                return 0;

        remote_wakeup = dev_pm_qos_flags(dev, PM_QOS_FLAG_REMOTE_WAKEUP) >
                                PM_QOS_FLAGS_NONE;
        error = acpi_device_wakeup(adev, ACPI_STATE_S0, remote_wakeup);
        if (remote_wakeup && error)
                return -EAGAIN;

        error = acpi_dev_pm_low_power(dev, adev, ACPI_STATE_S0);
        if (error)
                acpi_device_wakeup(adev, ACPI_STATE_S0, false);

        return error;
}
EXPORT_SYMBOL_GPL(acpi_dev_runtime_suspend);

/**
 * acpi_dev_runtime_resume - Put device into the full-power state using ACPI.
 * @dev: Device to put into the full-power state.
 *
 * Put the given device into the full-power state using the standard ACPI
 * mechanism at run time.  Set the power state of the device to ACPI D0 and
 * disable remote wakeup.
 */
int acpi_dev_runtime_resume(struct device *dev)
{
        struct acpi_device *adev = ACPI_COMPANION(dev);
        int error;

        if (!adev)
                return 0;

        error = acpi_dev_pm_full_power(adev);
        acpi_device_wakeup(adev, ACPI_STATE_S0, false);
        return error;
}
EXPORT_SYMBOL_GPL(acpi_dev_runtime_resume);

/**
 * acpi_subsys_runtime_suspend - Suspend device using ACPI.
 * @dev: Device to suspend.
 *
 * Carry out the generic runtime suspend procedure for @dev and use ACPI to put
 * it into a runtime low-power state.
 */
int acpi_subsys_runtime_suspend(struct device *dev)
{
        int ret = pm_generic_runtime_suspend(dev);
        return ret ? ret : acpi_dev_runtime_suspend(dev);
}
EXPORT_SYMBOL_GPL(acpi_subsys_runtime_suspend);

/**
 * acpi_subsys_runtime_resume - Resume device using ACPI.
 * @dev: Device to Resume.
 *
 * Use ACPI to put the given device into the full-power state and carry out the
 * generic runtime resume procedure for it.
 */
int acpi_subsys_runtime_resume(struct device *dev)
{
        int ret = acpi_dev_runtime_resume(dev);
        return ret ? ret : pm_generic_runtime_resume(dev);
}
EXPORT_SYMBOL_GPL(acpi_subsys_runtime_resume);

#ifdef CONFIG_PM_SLEEP
/**
 * acpi_dev_suspend_late - Put device into a low-power state using ACPI.
 * @dev: Device to put into a low-power state.
 *
 * Put the given device into a low-power state during system transition to a
 * sleep state using the standard ACPI mechanism.  Set up system wakeup if
 * desired, choose the state to put the device into (this checks if system
 * wakeup is expected to work too), and set the power state of the device.
 */
int acpi_dev_suspend_late(struct device *dev)
{
        struct acpi_device *adev = ACPI_COMPANION(dev);
        u32 target_state;
        bool wakeup;
        int error;

        if (!adev)
                return 0;

        target_state = acpi_target_system_state();
        wakeup = device_may_wakeup(dev) && acpi_device_can_wakeup(adev);
        error = acpi_device_wakeup(adev, target_state, wakeup);
        if (wakeup && error)
                return error;

        error = acpi_dev_pm_low_power(dev, adev, target_state);
        if (error)
                acpi_device_wakeup(adev, ACPI_STATE_UNKNOWN, false);

        return error;
}
EXPORT_SYMBOL_GPL(acpi_dev_suspend_late);

/**
 * acpi_dev_resume_early - Put device into the full-power state using ACPI.
 * @dev: Device to put into the full-power state.
 *
 * Put the given device into the full-power state using the standard ACPI
 * mechanism during system transition to the working state.  Set the power
 * state of the device to ACPI D0 and disable remote wakeup.
 */
int acpi_dev_resume_early(struct device *dev)
{
        struct acpi_device *adev = ACPI_COMPANION(dev);
        int error;

        if (!adev)
                return 0;

        error = acpi_dev_pm_full_power(adev);
        acpi_device_wakeup(adev, ACPI_STATE_UNKNOWN, false);
        return error;
}
EXPORT_SYMBOL_GPL(acpi_dev_resume_early);

/**
 * acpi_subsys_prepare - Prepare device for system transition to a sleep state.
 * @dev: Device to prepare.
 */
int acpi_subsys_prepare(struct device *dev)
{
        struct acpi_device *adev = ACPI_COMPANION(dev);
        u32 sys_target;
        int ret, state;

        ret = pm_generic_prepare(dev);
        if (ret < 0)
                return ret;

        if (!adev || !pm_runtime_suspended(dev)
            || device_may_wakeup(dev) != !!adev->wakeup.prepare_count)
                return 0;

        sys_target = acpi_target_system_state();
        if (sys_target == ACPI_STATE_S0)
                return 1;

        if (adev->power.flags.dsw_present)
                return 0;

        ret = acpi_dev_pm_get_state(dev, adev, sys_target, NULL, &state);
        return !ret && state == adev->power.state;
}
EXPORT_SYMBOL_GPL(acpi_subsys_prepare);

/**
 * acpi_subsys_suspend - Run the device driver's suspend callback.
 * @dev: Device to handle.
 *
 * Follow PCI and resume devices suspended at run time before running their
 * system suspend callbacks.
 */
int acpi_subsys_suspend(struct device *dev)
{
        pm_runtime_resume(dev);
        return pm_generic_suspend(dev);
}
EXPORT_SYMBOL_GPL(acpi_subsys_suspend);

/**
 * acpi_subsys_suspend_late - Suspend device using ACPI.
 * @dev: Device to suspend.
 *
 * Carry out the generic late suspend procedure for @dev and use ACPI to put
 * it into a low-power state during system transition into a sleep state.
 */
int acpi_subsys_suspend_late(struct device *dev)
{
        int ret = pm_generic_suspend_late(dev);
        return ret ? ret : acpi_dev_suspend_late(dev);
}
EXPORT_SYMBOL_GPL(acpi_subsys_suspend_late);

/**
 * acpi_subsys_resume_early - Resume device using ACPI.
 * @dev: Device to Resume.
 *
 * Use ACPI to put the given device into the full-power state and carry out the
 * generic early resume procedure for it during system transition into the

 * working state.
 */
int acpi_subsys_resume_early(struct device *dev)
{
        int ret = acpi_dev_resume_early(dev);
        return ret ? ret : pm_generic_resume_early(dev);
}
EXPORT_SYMBOL_GPL(acpi_subsys_resume_early);

/**
 * acpi_subsys_freeze - Run the device driver's freeze callback.
 * @dev: Device to handle.
 */
int acpi_subsys_freeze(struct device *dev)
{
        /*
         * This used to be done in acpi_subsys_prepare() for all devices and
         * some drivers may depend on it, so do it here.  Ideally, however,
         * runtime-suspended devices should not be touched during freeze/thaw
         * transitions.
         */
        pm_runtime_resume(dev);
        return pm_generic_freeze(dev);
}
EXPORT_SYMBOL_GPL(acpi_subsys_freeze);

#endif /* CONFIG_PM_SLEEP */

static struct dev_pm_domain acpi_general_pm_domain = {
        .ops = {
                .runtime_suspend = acpi_subsys_runtime_suspend,
                .runtime_resume = acpi_subsys_runtime_resume,
#ifdef CONFIG_PM_SLEEP
                .prepare = acpi_subsys_prepare,
                .complete = pm_complete_with_resume_check,
                .suspend = acpi_subsys_suspend,
                .suspend_late = acpi_subsys_suspend_late,
                .resume_early = acpi_subsys_resume_early,
                .freeze = acpi_subsys_freeze,
                .poweroff = acpi_subsys_suspend,
                .poweroff_late = acpi_subsys_suspend_late,
                .restore_early = acpi_subsys_resume_early,
#endif
        },
};

/**
 * acpi_dev_pm_detach - Remove ACPI power management from the device.
 * @dev: Device to take care of.
 * @power_off: Whether or not to try to remove power from the device.
 *
 * Remove the device from the general ACPI PM domain and remove its wakeup
 * notifier.  If @power_off is set, additionally remove power from the device if
 * possible.
 *
 * Callers must ensure proper synchronization of this function with power
 * management callbacks.
 */
static void acpi_dev_pm_detach(struct device *dev, bool power_off)
{
        struct acpi_device *adev = ACPI_COMPANION(dev);

        if (adev && dev->pm_domain == &acpi_general_pm_domain) {
                dev_pm_domain_set(dev, NULL);
                acpi_remove_pm_notifier(adev);
                if (power_off) {
                        /*
                         * If the device's PM QoS resume latency limit or flags
                         * have been exposed to user space, they have to be
                         * hidden at this point, so that they don't affect the
                         * choice of the low-power state to put the device into.
                         */
                        dev_pm_qos_hide_latency_limit(dev);
                        dev_pm_qos_hide_flags(dev);
                        acpi_device_wakeup(adev, ACPI_STATE_S0, false);
                        acpi_dev_pm_low_power(dev, adev, ACPI_STATE_S0);
                }
        }
}

/**
 * acpi_dev_pm_attach - Prepare device for ACPI power management.
 * @dev: Device to prepare.
 * @power_on: Whether or not to power on the device.
 *
 * If @dev has a valid ACPI handle that has a valid struct acpi_device object
 * attached to it, install a wakeup notification handler for the device and
 * add it to the general ACPI PM domain.  If @power_on is set, the device will
 * be put into the ACPI D0 state before the function returns.
 *
 * This assumes that the @dev's bus type uses generic power management callbacks
 * (or doesn't use any power management callbacks at all).
 *
 * Callers must ensure proper synchronization of this function with power
 * management callbacks.
 */
int acpi_dev_pm_attach(struct device *dev, bool power_on)
{
        struct acpi_device *adev = ACPI_COMPANION(dev);

        if (!adev)
                return -ENODEV;

        if (dev->pm_domain)
                return -EEXIST;

        /*
         * Only attach the power domain to the first device if the
         * companion is shared by multiple. This is to prevent doing power
         * management twice.
         */
        if (!acpi_device_is_first_physical_node(adev, dev))
                return -EBUSY;

        acpi_add_pm_notifier(adev, dev, acpi_pm_notify_work_func);
        dev_pm_domain_set(dev, &acpi_general_pm_domain);
        if (power_on) {
                acpi_dev_pm_full_power(adev);
                acpi_device_wakeup(adev, ACPI_STATE_S0, false);
        }

        dev->pm_domain->detach = acpi_dev_pm_detach;
        return 0;
}
EXPORT_SYMBOL_GPL(acpi_dev_pm_attach);
#endif /* CONFIG_PM */