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  /*
   * drivers/base/power/main.c - Where the driver meets power management.
   *
   * Copyright (c) 2003 Patrick Mochel
   * Copyright (c) 2003 Open Source Development Lab
   *
   * This file is released under the GPLv2
   *
   *
  * The driver model core calls device_pm_add() when a device is registered.
  * This will intialize the embedded device_pm_info object in the device
  * and add it to the list of power-controlled devices. sysfs entries for
  * controlling device power management will also be added.
  *
  * A separate list is used for keeping track of power info, because the power
  * domain dependencies may differ from the ancestral dependencies that the
  * subsystem list maintains.
  */
 
 #include <linux/device.h>
 #include <linux/kallsyms.h>
 #include <linux/mutex.h>
 #include <linux/pm.h>
 #include <linux/resume-trace.h>
 #include <linux/rwsem.h>
 
 #include "../base.h"
 #include "power.h"
 
 /*
  * The entries in the dpm_list list are in a depth first order, simply
  * because children are guaranteed to be discovered after parents, and
  * are inserted at the back of the list on discovery.
  *
  * Since device_pm_add() may be called with a device semaphore held,
  * we must never try to acquire a device semaphore while holding
  * dpm_list_mutex.
  */
 
 LIST_HEAD(dpm_list);
 
 static DEFINE_MUTEX(dpm_list_mtx);
 
 /*
  * Set once the preparation of devices for a PM transition has started, reset
  * before starting to resume devices.  Protected by dpm_list_mtx.
  */
 static bool transition_started;
 
 /**
  *        device_pm_lock - lock the list of active devices used by the PM core
  */
 void device_pm_lock(void)
 {
         mutex_lock(&dpm_list_mtx);
 }
 
 /**
  *        device_pm_unlock - unlock the list of active devices used by the PM core
  */
 void device_pm_unlock(void)
 {
         mutex_unlock(&dpm_list_mtx);
 }
 
 /**
  *        device_pm_add - add a device to the list of active devices
  *        @dev:        Device to be added to the list
  */
 void device_pm_add(struct device *dev)
 {
         pr_debug("PM: Adding info for %s:%s\n",
                  dev->bus ? dev->bus->name : "No Bus",
                  kobject_name(&dev->kobj));
         mutex_lock(&dpm_list_mtx);
         if (dev->parent) {
                 if (dev->parent->power.status >= DPM_SUSPENDING)
                         dev_warn(dev, "parent %s should not be sleeping\n",
                                 dev->parent->bus_id);
         } else if (transition_started) {
                 /*
                  * We refuse to register parentless devices while a PM
                  * transition is in progress in order to avoid leaving them
                  * unhandled down the road
                  */
                 dev_WARN(dev, "Parentless device registered during a PM transaction\n");
         }
 
         list_add_tail(&dev->power.entry, &dpm_list);
         mutex_unlock(&dpm_list_mtx);
 }
 
 /**
  *        device_pm_remove - remove a device from the list of active devices
  *        @dev:        Device to be removed from the list
  *
  *        This function also removes the device's PM-related sysfs attributes.
  */
 void device_pm_remove(struct device *dev)
{
        pr_debug("PM: Removing info for %s:%s\n",
                 dev->bus ? dev->bus->name : "No Bus",
                 kobject_name(&dev->kobj));
        mutex_lock(&dpm_list_mtx);
        list_del_init(&dev->power.entry);
        mutex_unlock(&dpm_list_mtx);
}

/**
 *        pm_op - execute the PM operation appropiate for given PM event
 *        @dev:        Device.
 *        @ops:        PM operations to choose from.
 *        @state:        PM transition of the system being carried out.
 */
static int pm_op(struct device *dev, struct pm_ops *ops, pm_message_t state)
{
        int error = 0;

        switch (state.event) {
#ifdef CONFIG_SUSPEND
        case PM_EVENT_SUSPEND:
                if (ops->suspend) {
                        error = ops->suspend(dev);
                        suspend_report_result(ops->suspend, error);
                }
                break;
        case PM_EVENT_RESUME:
                if (ops->resume) {
                        error = ops->resume(dev);
                        suspend_report_result(ops->resume, error);
                }
                break;
#endif /* CONFIG_SUSPEND */
#ifdef CONFIG_HIBERNATION
        case PM_EVENT_FREEZE:
        case PM_EVENT_QUIESCE:
                if (ops->freeze) {
                        error = ops->freeze(dev);
                        suspend_report_result(ops->freeze, error);
                }
                break;
        case PM_EVENT_HIBERNATE:
                if (ops->poweroff) {
                        error = ops->poweroff(dev);
                        suspend_report_result(ops->poweroff, error);
                }
                break;
        case PM_EVENT_THAW:
        case PM_EVENT_RECOVER:
                if (ops->thaw) {
                        error = ops->thaw(dev);
                        suspend_report_result(ops->thaw, error);
                }
                break;
        case PM_EVENT_RESTORE:
                if (ops->restore) {
                        error = ops->restore(dev);
                        suspend_report_result(ops->restore, error);
                }
                break;
#endif /* CONFIG_HIBERNATION */
        default:
                error = -EINVAL;
        }
        return error;
}

/**
 *        pm_noirq_op - execute the PM operation appropiate for given PM event
 *        @dev:        Device.
 *        @ops:        PM operations to choose from.
 *        @state: PM transition of the system being carried out.
 *
 *        The operation is executed with interrupts disabled by the only remaining
 *        functional CPU in the system.
 */
static int pm_noirq_op(struct device *dev, struct pm_ext_ops *ops,
                        pm_message_t state)
{
        int error = 0;

        switch (state.event) {
#ifdef CONFIG_SUSPEND
        case PM_EVENT_SUSPEND:
                if (ops->suspend_noirq) {
                        error = ops->suspend_noirq(dev);
                        suspend_report_result(ops->suspend_noirq, error);
                }
                break;
        case PM_EVENT_RESUME:
                if (ops->resume_noirq) {
                        error = ops->resume_noirq(dev);
                        suspend_report_result(ops->resume_noirq, error);
                }
                break;
#endif /* CONFIG_SUSPEND */
#ifdef CONFIG_HIBERNATION
        case PM_EVENT_FREEZE:
        case PM_EVENT_QUIESCE:
                if (ops->freeze_noirq) {
                        error = ops->freeze_noirq(dev);
                        suspend_report_result(ops->freeze_noirq, error);
                }
                break;
        case PM_EVENT_HIBERNATE:
                if (ops->poweroff_noirq) {
                        error = ops->poweroff_noirq(dev);
                        suspend_report_result(ops->poweroff_noirq, error);
                }
                break;
        case PM_EVENT_THAW:
        case PM_EVENT_RECOVER:
                if (ops->thaw_noirq) {
                        error = ops->thaw_noirq(dev);
                        suspend_report_result(ops->thaw_noirq, error);
                }
                break;
        case PM_EVENT_RESTORE:
                if (ops->restore_noirq) {
                        error = ops->restore_noirq(dev);
                        suspend_report_result(ops->restore_noirq, error);
                }
                break;
#endif /* CONFIG_HIBERNATION */
        default:
                error = -EINVAL;
        }
        return error;
}

static char *pm_verb(int event)
{
        switch (event) {
        case PM_EVENT_SUSPEND:
                return "suspend";
        case PM_EVENT_RESUME:
                return "resume";
        case PM_EVENT_FREEZE:
                return "freeze";
        case PM_EVENT_QUIESCE:
                return "quiesce";
        case PM_EVENT_HIBERNATE:
                return "hibernate";
        case PM_EVENT_THAW:
                return "thaw";
        case PM_EVENT_RESTORE:
                return "restore";
        case PM_EVENT_RECOVER:
                return "recover";
        default:
                return "(unknown PM event)";
        }
}

static void pm_dev_dbg(struct device *dev, pm_message_t state, char *info)
{
        dev_dbg(dev, "%s%s%s\n", info, pm_verb(state.event),
                ((state.event & PM_EVENT_SLEEP) && device_may_wakeup(dev)) ?
                ", may wakeup" : "");
}

static void pm_dev_err(struct device *dev, pm_message_t state, char *info,
                        int error)
{
        printk(KERN_ERR "PM: Device %s failed to %s%s: error %d\n",
                kobject_name(&dev->kobj), pm_verb(state.event), info, error);
}

/*------------------------- Resume routines -------------------------*/

/**
 *        resume_device_noirq - Power on one device (early resume).
 *        @dev:        Device.
 *        @state: PM transition of the system being carried out.
 *
 *        Must be called with interrupts disabled.
 */
static int resume_device_noirq(struct device *dev, pm_message_t state)
{
        int error = 0;

        TRACE_DEVICE(dev);
        TRACE_RESUME(0);

        if (!dev->bus)
                goto End;

        if (dev->bus->pm) {
                pm_dev_dbg(dev, state, "EARLY ");
                error = pm_noirq_op(dev, dev->bus->pm, state);
        } else if (dev->bus->resume_early) {
                pm_dev_dbg(dev, state, "legacy EARLY ");
                error = dev->bus->resume_early(dev);
        }
 End:
        TRACE_RESUME(error);
        return error;
}

/**
 *        dpm_power_up - Power on all regular (non-sysdev) devices.
 *        @state: PM transition of the system being carried out.
 *
 *        Execute the appropriate "noirq resume" callback for all devices marked
 *        as DPM_OFF_IRQ.
 *
 *        Must be called with interrupts disabled and only one CPU running.
 */
static void dpm_power_up(pm_message_t state)
{
        struct device *dev;

        list_for_each_entry(dev, &dpm_list, power.entry)
                if (dev->power.status > DPM_OFF) {
                        int error;

                        dev->power.status = DPM_OFF;
                        error = resume_device_noirq(dev, state);
                        if (error)
                                pm_dev_err(dev, state, " early", error);
                }
}

/**
 *        device_power_up - Turn on all devices that need special attention.
 *        @state: PM transition of the system being carried out.
 *
 *        Power on system devices, then devices that required we shut them down
 *        with interrupts disabled.
 *
 *        Must be called with interrupts disabled.
 */
void device_power_up(pm_message_t state)
{
        sysdev_resume();
        dpm_power_up(state);
}
EXPORT_SYMBOL_GPL(device_power_up);

/**
 *        resume_device - Restore state for one device.
 *        @dev:        Device.
 *        @state: PM transition of the system being carried out.
 */
static int resume_device(struct device *dev, pm_message_t state)
{
        int error = 0;

        TRACE_DEVICE(dev);
        TRACE_RESUME(0);

        down(&dev->sem);

        if (dev->bus) {
                if (dev->bus->pm) {
                        pm_dev_dbg(dev, state, "");
                        error = pm_op(dev, &dev->bus->pm->base, state);
                } else if (dev->bus->resume) {
                        pm_dev_dbg(dev, state, "legacy ");
                        error = dev->bus->resume(dev);
                }
                if (error)
                        goto End;
        }

        if (dev->type) {
                if (dev->type->pm) {
                        pm_dev_dbg(dev, state, "type ");
                        error = pm_op(dev, dev->type->pm, state);
                } else if (dev->type->resume) {
                        pm_dev_dbg(dev, state, "legacy type ");
                        error = dev->type->resume(dev);
                }
                if (error)
                        goto End;
        }

        if (dev->class) {
                if (dev->class->pm) {
                        pm_dev_dbg(dev, state, "class ");
                        error = pm_op(dev, dev->class->pm, state);
                } else if (dev->class->resume) {
                        pm_dev_dbg(dev, state, "legacy class ");
                        error = dev->class->resume(dev);
                }
        }
 End:
        up(&dev->sem);

        TRACE_RESUME(error);
        return error;
}

/**
 *        dpm_resume - Resume every device.
 *        @state: PM transition of the system being carried out.
 *
 *        Execute the appropriate "resume" callback for all devices the status of
 *        which indicates that they are inactive.
 */
static void dpm_resume(pm_message_t state)
{
        struct list_head list;

        INIT_LIST_HEAD(&list);
        mutex_lock(&dpm_list_mtx);
        transition_started = false;
        while (!list_empty(&dpm_list)) {
                struct device *dev = to_device(dpm_list.next);

                get_device(dev);
                if (dev->power.status >= DPM_OFF) {
                        int error;

                        dev->power.status = DPM_RESUMING;
                        mutex_unlock(&dpm_list_mtx);

                        error = resume_device(dev, state);

                        mutex_lock(&dpm_list_mtx);
                        if (error)
                                pm_dev_err(dev, state, "", error);
                } else if (dev->power.status == DPM_SUSPENDING) {
                        /* Allow new children of the device to be registered */
                        dev->power.status = DPM_RESUMING;
                }
                if (!list_empty(&dev->power.entry))
                        list_move_tail(&dev->power.entry, &list);
                put_device(dev);
        }
        list_splice(&list, &dpm_list);
        mutex_unlock(&dpm_list_mtx);
}

/**
 *        complete_device - Complete a PM transition for given device
 *        @dev:        Device.
 *        @state: PM transition of the system being carried out.
 */
static void complete_device(struct device *dev, pm_message_t state)
{
        down(&dev->sem);

        if (dev->class && dev->class->pm && dev->class->pm->complete) {
                pm_dev_dbg(dev, state, "completing class ");
                dev->class->pm->complete(dev);
        }

        if (dev->type && dev->type->pm && dev->type->pm->complete) {
                pm_dev_dbg(dev, state, "completing type ");
                dev->type->pm->complete(dev);
        }

        if (dev->bus && dev->bus->pm && dev->bus->pm->base.complete) {
                pm_dev_dbg(dev, state, "completing ");
                dev->bus->pm->base.complete(dev);
        }

        up(&dev->sem);
}

/**
 *        dpm_complete - Complete a PM transition for all devices.
 *        @state: PM transition of the system being carried out.
 *
 *        Execute the ->complete() callbacks for all devices that are not marked
 *        as DPM_ON.
 */
static void dpm_complete(pm_message_t state)
{
        struct list_head list;

        INIT_LIST_HEAD(&list);
        mutex_lock(&dpm_list_mtx);
        while (!list_empty(&dpm_list)) {
                struct device *dev = to_device(dpm_list.prev);

                get_device(dev);
                if (dev->power.status > DPM_ON) {
                        dev->power.status = DPM_ON;
                        mutex_unlock(&dpm_list_mtx);

                        complete_device(dev, state);

                        mutex_lock(&dpm_list_mtx);
                }
                if (!list_empty(&dev->power.entry))
                        list_move(&dev->power.entry, &list);
                put_device(dev);
        }
        list_splice(&list, &dpm_list);
        mutex_unlock(&dpm_list_mtx);
}

/**
 *        device_resume - Restore state of each device in system.
 *        @state: PM transition of the system being carried out.
 *
 *        Resume all the devices, unlock them all, and allow new
 *        devices to be registered once again.
 */
void device_resume(pm_message_t state)
{
        might_sleep();
        dpm_resume(state);
        dpm_complete(state);
}
EXPORT_SYMBOL_GPL(device_resume);


/*------------------------- Suspend routines -------------------------*/

/**
 *        resume_event - return a PM message representing the resume event
 *                       corresponding to given sleep state.
 *        @sleep_state: PM message representing a sleep state.
 */
static pm_message_t resume_event(pm_message_t sleep_state)
{
        switch (sleep_state.event) {
        case PM_EVENT_SUSPEND:
                return PMSG_RESUME;
        case PM_EVENT_FREEZE:
        case PM_EVENT_QUIESCE:
                return PMSG_RECOVER;
        case PM_EVENT_HIBERNATE:
                return PMSG_RESTORE;
        }
        return PMSG_ON;
}

/**
 *        suspend_device_noirq - Shut down one device (late suspend).
 *        @dev:        Device.
 *        @state: PM transition of the system being carried out.
 *
 *        This is called with interrupts off and only a single CPU running.
 */
static int suspend_device_noirq(struct device *dev, pm_message_t state)
{
        int error = 0;

        if (!dev->bus)
                return 0;

        if (dev->bus->pm) {
                pm_dev_dbg(dev, state, "LATE ");
                error = pm_noirq_op(dev, dev->bus->pm, state);
        } else if (dev->bus->suspend_late) {
                pm_dev_dbg(dev, state, "legacy LATE ");
                error = dev->bus->suspend_late(dev, state);
                suspend_report_result(dev->bus->suspend_late, error);
        }
        return error;
}

/**
 *        device_power_down - Shut down special devices.
 *        @state: PM transition of the system being carried out.
 *
 *        Power down devices that require interrupts to be disabled.
 *        Then power down system devices.
 *
 *        Must be called with interrupts disabled and only one CPU running.
 */
int device_power_down(pm_message_t state)
{
        struct device *dev;
        int error = 0;

        list_for_each_entry_reverse(dev, &dpm_list, power.entry) {
                error = suspend_device_noirq(dev, state);
                if (error) {
                        pm_dev_err(dev, state, " late", error);
                        break;
                }
                dev->power.status = DPM_OFF_IRQ;
        }
        if (!error)
                error = sysdev_suspend(state);
        if (error)
                dpm_power_up(resume_event(state));
        return error;
}
EXPORT_SYMBOL_GPL(device_power_down);

/**
 *        suspend_device - Save state of one device.
 *        @dev:        Device.
 *        @state: PM transition of the system being carried out.
 */
static int suspend_device(struct device *dev, pm_message_t state)
{
        int error = 0;

        down(&dev->sem);

        if (dev->class) {
                if (dev->class->pm) {
                        pm_dev_dbg(dev, state, "class ");
                        error = pm_op(dev, dev->class->pm, state);
                } else if (dev->class->suspend) {
                        pm_dev_dbg(dev, state, "legacy class ");
                        error = dev->class->suspend(dev, state);
                        suspend_report_result(dev->class->suspend, error);
                }
                if (error)
                        goto End;
        }

        if (dev->type) {
                if (dev->type->pm) {
                        pm_dev_dbg(dev, state, "type ");
                        error = pm_op(dev, dev->type->pm, state);
                } else if (dev->type->suspend) {
                        pm_dev_dbg(dev, state, "legacy type ");
                        error = dev->type->suspend(dev, state);
                        suspend_report_result(dev->type->suspend, error);
                }
                if (error)
                        goto End;
        }

        if (dev->bus) {
                if (dev->bus->pm) {
                        pm_dev_dbg(dev, state, "");
                        error = pm_op(dev, &dev->bus->pm->base, state);
                } else if (dev->bus->suspend) {
                        pm_dev_dbg(dev, state, "legacy ");
                        error = dev->bus->suspend(dev, state);
                        suspend_report_result(dev->bus->suspend, error);
                }
        }
 End:
        up(&dev->sem);

        return error;
}

/**
 *        dpm_suspend - Suspend every device.
 *        @state: PM transition of the system being carried out.
 *
 *        Execute the appropriate "suspend" callbacks for all devices.
 */
static int dpm_suspend(pm_message_t state)
{
        struct list_head list;
        int error = 0;

        INIT_LIST_HEAD(&list);
        mutex_lock(&dpm_list_mtx);
        while (!list_empty(&dpm_list)) {
                struct device *dev = to_device(dpm_list.prev);

                get_device(dev);
                mutex_unlock(&dpm_list_mtx);

                error = suspend_device(dev, state);

                mutex_lock(&dpm_list_mtx);
                if (error) {
                        pm_dev_err(dev, state, "", error);
                        put_device(dev);
                        break;
                }
                dev->power.status = DPM_OFF;
                if (!list_empty(&dev->power.entry))
                        list_move(&dev->power.entry, &list);
                put_device(dev);
        }
        list_splice(&list, dpm_list.prev);
        mutex_unlock(&dpm_list_mtx);
        return error;
}

/**
 *        prepare_device - Execute the ->prepare() callback(s) for given device.
 *        @dev:        Device.
 *        @state: PM transition of the system being carried out.
 */
static int prepare_device(struct device *dev, pm_message_t state)
{
        int error = 0;

        down(&dev->sem);

        if (dev->bus && dev->bus->pm && dev->bus->pm->base.prepare) {
                pm_dev_dbg(dev, state, "preparing ");
                error = dev->bus->pm->base.prepare(dev);
                suspend_report_result(dev->bus->pm->base.prepare, error);
                if (error)
                        goto End;
        }

        if (dev->type && dev->type->pm && dev->type->pm->prepare) {
                pm_dev_dbg(dev, state, "preparing type ");
                error = dev->type->pm->prepare(dev);
                suspend_report_result(dev->type->pm->prepare, error);
                if (error)
                        goto End;
        }

        if (dev->class && dev->class->pm && dev->class->pm->prepare) {
                pm_dev_dbg(dev, state, "preparing class ");
                error = dev->class->pm->prepare(dev);
                suspend_report_result(dev->class->pm->prepare, error);
        }
 End:
        up(&dev->sem);

        return error;
}

/**
 *        dpm_prepare - Prepare all devices for a PM transition.
 *        @state: PM transition of the system being carried out.
 *
 *        Execute the ->prepare() callback for all devices.
 */
static int dpm_prepare(pm_message_t state)
{
        struct list_head list;
        int error = 0;

        INIT_LIST_HEAD(&list);
        mutex_lock(&dpm_list_mtx);
        transition_started = true;
        while (!list_empty(&dpm_list)) {
                struct device *dev = to_device(dpm_list.next);

                get_device(dev);
                dev->power.status = DPM_PREPARING;
                mutex_unlock(&dpm_list_mtx);

                error = prepare_device(dev, state);

                mutex_lock(&dpm_list_mtx);
                if (error) {
                        dev->power.status = DPM_ON;
                        if (error == -EAGAIN) {
                                put_device(dev);
                                continue;
                        }
                        printk(KERN_ERR "PM: Failed to prepare device %s "
                                "for power transition: error %d\n",
                                kobject_name(&dev->kobj), error);
                        put_device(dev);
                        break;
                }
                dev->power.status = DPM_SUSPENDING;
                if (!list_empty(&dev->power.entry))
                        list_move_tail(&dev->power.entry, &list);
                put_device(dev);
        }
        list_splice(&list, &dpm_list);
        mutex_unlock(&dpm_list_mtx);
        return error;
}

/**
 *        device_suspend - Save state and stop all devices in system.
 *        @state: PM transition of the system being carried out.
 *
 *        Prepare and suspend all devices.
 */
int device_suspend(pm_message_t state)
{
        int error;

        might_sleep();
        error = dpm_prepare(state);
        if (!error)
                error = dpm_suspend(state);
        return error;
}
EXPORT_SYMBOL_GPL(device_suspend);

void __suspend_report_result(const char *function, void *fn, int ret)
{
        if (ret)
                printk(KERN_ERR "%s(): %pF returns %d\n", function, fn, ret);
}
EXPORT_SYMBOL_GPL(__suspend_report_result);