9617c3e460
Move the declaration of device_pm_schedule_removal() to device.h and make it exported, as it will be used directly by some drivers for unregistering device objects during suspend/resume cycles in a safe way. Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl> Acked-by: Pavel Machek <pavel@ucw.cz> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
553 lines
14 KiB
C
553 lines
14 KiB
C
/*
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* drivers/base/power/main.c - Where the driver meets power management.
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*
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* Copyright (c) 2003 Patrick Mochel
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* Copyright (c) 2003 Open Source Development Lab
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*
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* This file is released under the GPLv2
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*
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*
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* The driver model core calls device_pm_add() when a device is registered.
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* This will intialize the embedded device_pm_info object in the device
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* and add it to the list of power-controlled devices. sysfs entries for
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* controlling device power management will also be added.
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*
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* A different set of lists than the global subsystem list are used to
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* keep track of power info because we use different lists to hold
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* devices based on what stage of the power management process they
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* are in. The power domain dependencies may also differ from the
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* ancestral dependencies that the subsystem list maintains.
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*/
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#include <linux/device.h>
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#include <linux/kallsyms.h>
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#include <linux/mutex.h>
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#include <linux/pm.h>
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#include <linux/resume-trace.h>
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#include <linux/rwsem.h>
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#include "../base.h"
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#include "power.h"
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/*
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* The entries in the dpm_active list are in a depth first order, simply
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* because children are guaranteed to be discovered after parents, and
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* are inserted at the back of the list on discovery.
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*
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* All the other lists are kept in the same order, for consistency.
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* However the lists aren't always traversed in the same order.
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* Semaphores must be acquired from the top (i.e., front) down
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* and released in the opposite order. Devices must be suspended
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* from the bottom (i.e., end) up and resumed in the opposite order.
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* That way no parent will be suspended while it still has an active
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* child.
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*
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* Since device_pm_add() may be called with a device semaphore held,
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* we must never try to acquire a device semaphore while holding
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* dpm_list_mutex.
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*/
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LIST_HEAD(dpm_active);
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static LIST_HEAD(dpm_locked);
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static LIST_HEAD(dpm_off);
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static LIST_HEAD(dpm_off_irq);
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static LIST_HEAD(dpm_destroy);
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static DEFINE_MUTEX(dpm_list_mtx);
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static DECLARE_RWSEM(pm_sleep_rwsem);
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int (*platform_enable_wakeup)(struct device *dev, int is_on);
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/**
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* device_pm_add - add a device to the list of active devices
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* @dev: Device to be added to the list
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*/
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void device_pm_add(struct device *dev)
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{
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pr_debug("PM: Adding info for %s:%s\n",
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dev->bus ? dev->bus->name : "No Bus",
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kobject_name(&dev->kobj));
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mutex_lock(&dpm_list_mtx);
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list_add_tail(&dev->power.entry, &dpm_active);
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mutex_unlock(&dpm_list_mtx);
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}
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/**
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* device_pm_remove - remove a device from the list of active devices
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* @dev: Device to be removed from the list
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*
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* This function also removes the device's PM-related sysfs attributes.
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*/
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void device_pm_remove(struct device *dev)
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{
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/*
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* If this function is called during a suspend, it will be blocked,
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* because we're holding the device's semaphore at that time, which may
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* lead to a deadlock. In that case we want to print a warning.
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* However, it may also be called by unregister_dropped_devices() with
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* the device's semaphore released, in which case the warning should
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* not be printed.
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*/
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if (down_trylock(&dev->sem)) {
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if (down_read_trylock(&pm_sleep_rwsem)) {
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/* No suspend in progress, wait on dev->sem */
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down(&dev->sem);
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up_read(&pm_sleep_rwsem);
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} else {
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/* Suspend in progress, we may deadlock */
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dev_warn(dev, "Suspicious %s during suspend\n",
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__FUNCTION__);
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dump_stack();
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/* The user has been warned ... */
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down(&dev->sem);
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}
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}
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pr_debug("PM: Removing info for %s:%s\n",
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dev->bus ? dev->bus->name : "No Bus",
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kobject_name(&dev->kobj));
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mutex_lock(&dpm_list_mtx);
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dpm_sysfs_remove(dev);
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list_del_init(&dev->power.entry);
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mutex_unlock(&dpm_list_mtx);
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up(&dev->sem);
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}
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/**
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* device_pm_schedule_removal - schedule the removal of a suspended device
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* @dev: Device to destroy
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*
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* Moves the device to the dpm_destroy list for further processing by
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* unregister_dropped_devices().
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*/
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void device_pm_schedule_removal(struct device *dev)
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{
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pr_debug("PM: Preparing for removal: %s:%s\n",
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dev->bus ? dev->bus->name : "No Bus",
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kobject_name(&dev->kobj));
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mutex_lock(&dpm_list_mtx);
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list_move_tail(&dev->power.entry, &dpm_destroy);
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mutex_unlock(&dpm_list_mtx);
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}
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EXPORT_SYMBOL_GPL(device_pm_schedule_removal);
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/**
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* pm_sleep_lock - mutual exclusion for registration and suspend
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*
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* Returns 0 if no suspend is underway and device registration
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* may proceed, otherwise -EBUSY.
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*/
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int pm_sleep_lock(void)
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{
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if (down_read_trylock(&pm_sleep_rwsem))
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return 0;
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return -EBUSY;
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}
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/**
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* pm_sleep_unlock - mutual exclusion for registration and suspend
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*
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* This routine undoes the effect of device_pm_add_lock
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* when a device's registration is complete.
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*/
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void pm_sleep_unlock(void)
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{
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up_read(&pm_sleep_rwsem);
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}
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/*------------------------- Resume routines -------------------------*/
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/**
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* resume_device_early - Power on one device (early resume).
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* @dev: Device.
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*
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* Must be called with interrupts disabled.
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*/
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static int resume_device_early(struct device *dev)
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{
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int error = 0;
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TRACE_DEVICE(dev);
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TRACE_RESUME(0);
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if (dev->bus && dev->bus->resume_early) {
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dev_dbg(dev, "EARLY resume\n");
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error = dev->bus->resume_early(dev);
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}
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TRACE_RESUME(error);
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return error;
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}
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/**
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* dpm_power_up - Power on all regular (non-sysdev) devices.
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*
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* Walk the dpm_off_irq list and power each device up. This
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* is used for devices that required they be powered down with
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* interrupts disabled. As devices are powered on, they are moved
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* to the dpm_off list.
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*
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* Must be called with interrupts disabled and only one CPU running.
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*/
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static void dpm_power_up(void)
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{
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while (!list_empty(&dpm_off_irq)) {
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struct list_head *entry = dpm_off_irq.next;
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struct device *dev = to_device(entry);
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list_move_tail(entry, &dpm_off);
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resume_device_early(dev);
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}
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}
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/**
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* device_power_up - Turn on all devices that need special attention.
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*
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* Power on system devices, then devices that required we shut them down
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* with interrupts disabled.
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*
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* Must be called with interrupts disabled.
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*/
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void device_power_up(void)
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{
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sysdev_resume();
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dpm_power_up();
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}
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EXPORT_SYMBOL_GPL(device_power_up);
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/**
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* resume_device - Restore state for one device.
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* @dev: Device.
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*
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*/
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static int resume_device(struct device *dev)
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{
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int error = 0;
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TRACE_DEVICE(dev);
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TRACE_RESUME(0);
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if (dev->bus && dev->bus->resume) {
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dev_dbg(dev,"resuming\n");
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error = dev->bus->resume(dev);
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}
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if (!error && dev->type && dev->type->resume) {
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dev_dbg(dev,"resuming\n");
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error = dev->type->resume(dev);
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}
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if (!error && dev->class && dev->class->resume) {
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dev_dbg(dev,"class resume\n");
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error = dev->class->resume(dev);
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}
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TRACE_RESUME(error);
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return error;
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}
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/**
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* dpm_resume - Resume every device.
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*
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* Resume the devices that have either not gone through
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* the late suspend, or that did go through it but also
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* went through the early resume.
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*
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* Take devices from the dpm_off_list, resume them,
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* and put them on the dpm_locked list.
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*/
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static void dpm_resume(void)
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{
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mutex_lock(&dpm_list_mtx);
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while(!list_empty(&dpm_off)) {
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struct list_head *entry = dpm_off.next;
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struct device *dev = to_device(entry);
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list_move_tail(entry, &dpm_locked);
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mutex_unlock(&dpm_list_mtx);
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resume_device(dev);
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mutex_lock(&dpm_list_mtx);
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}
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mutex_unlock(&dpm_list_mtx);
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}
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/**
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* unlock_all_devices - Release each device's semaphore
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*
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* Go through the dpm_off list. Put each device on the dpm_active
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* list and unlock it.
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*/
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static void unlock_all_devices(void)
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{
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mutex_lock(&dpm_list_mtx);
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while (!list_empty(&dpm_locked)) {
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struct list_head *entry = dpm_locked.prev;
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struct device *dev = to_device(entry);
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list_move(entry, &dpm_active);
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up(&dev->sem);
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}
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mutex_unlock(&dpm_list_mtx);
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}
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/**
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* unregister_dropped_devices - Unregister devices scheduled for removal
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*
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* Unregister all devices on the dpm_destroy list.
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*/
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static void unregister_dropped_devices(void)
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{
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mutex_lock(&dpm_list_mtx);
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while (!list_empty(&dpm_destroy)) {
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struct list_head *entry = dpm_destroy.next;
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struct device *dev = to_device(entry);
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up(&dev->sem);
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mutex_unlock(&dpm_list_mtx);
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/* This also removes the device from the list */
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device_unregister(dev);
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mutex_lock(&dpm_list_mtx);
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}
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mutex_unlock(&dpm_list_mtx);
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}
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/**
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* device_resume - Restore state of each device in system.
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*
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* Resume all the devices, unlock them all, and allow new
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* devices to be registered once again.
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*/
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void device_resume(void)
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{
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might_sleep();
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dpm_resume();
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unlock_all_devices();
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unregister_dropped_devices();
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up_write(&pm_sleep_rwsem);
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}
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EXPORT_SYMBOL_GPL(device_resume);
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/*------------------------- Suspend routines -------------------------*/
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static inline char *suspend_verb(u32 event)
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{
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switch (event) {
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case PM_EVENT_SUSPEND: return "suspend";
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case PM_EVENT_FREEZE: return "freeze";
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case PM_EVENT_PRETHAW: return "prethaw";
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default: return "(unknown suspend event)";
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}
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}
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static void
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suspend_device_dbg(struct device *dev, pm_message_t state, char *info)
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{
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dev_dbg(dev, "%s%s%s\n", info, suspend_verb(state.event),
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((state.event == PM_EVENT_SUSPEND) && device_may_wakeup(dev)) ?
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", may wakeup" : "");
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}
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/**
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* suspend_device_late - Shut down one device (late suspend).
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* @dev: Device.
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* @state: Power state device is entering.
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*
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* This is called with interrupts off and only a single CPU running.
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*/
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static int suspend_device_late(struct device *dev, pm_message_t state)
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{
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int error = 0;
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if (dev->bus && dev->bus->suspend_late) {
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suspend_device_dbg(dev, state, "LATE ");
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error = dev->bus->suspend_late(dev, state);
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suspend_report_result(dev->bus->suspend_late, error);
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}
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return error;
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}
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/**
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* device_power_down - Shut down special devices.
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* @state: Power state to enter.
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*
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* Power down devices that require interrupts to be disabled
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* and move them from the dpm_off list to the dpm_off_irq list.
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* Then power down system devices.
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*
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* Must be called with interrupts disabled and only one CPU running.
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*/
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int device_power_down(pm_message_t state)
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{
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int error = 0;
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while (!list_empty(&dpm_off)) {
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struct list_head *entry = dpm_off.prev;
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struct device *dev = to_device(entry);
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list_del_init(&dev->power.entry);
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error = suspend_device_late(dev, state);
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if (error) {
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printk(KERN_ERR "Could not power down device %s: "
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"error %d\n",
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kobject_name(&dev->kobj), error);
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if (list_empty(&dev->power.entry))
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list_add(&dev->power.entry, &dpm_off);
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break;
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}
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if (list_empty(&dev->power.entry))
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list_add(&dev->power.entry, &dpm_off_irq);
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}
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if (!error)
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error = sysdev_suspend(state);
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if (error)
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dpm_power_up();
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return error;
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}
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EXPORT_SYMBOL_GPL(device_power_down);
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/**
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* suspend_device - Save state of one device.
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* @dev: Device.
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* @state: Power state device is entering.
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*/
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int suspend_device(struct device *dev, pm_message_t state)
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{
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int error = 0;
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if (dev->power.power_state.event) {
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dev_dbg(dev, "PM: suspend %d-->%d\n",
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dev->power.power_state.event, state.event);
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}
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if (dev->class && dev->class->suspend) {
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suspend_device_dbg(dev, state, "class ");
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error = dev->class->suspend(dev, state);
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suspend_report_result(dev->class->suspend, error);
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}
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if (!error && dev->type && dev->type->suspend) {
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suspend_device_dbg(dev, state, "type ");
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error = dev->type->suspend(dev, state);
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suspend_report_result(dev->type->suspend, error);
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}
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if (!error && dev->bus && dev->bus->suspend) {
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suspend_device_dbg(dev, state, "");
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error = dev->bus->suspend(dev, state);
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suspend_report_result(dev->bus->suspend, error);
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}
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return error;
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}
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/**
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* dpm_suspend - Suspend every device.
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* @state: Power state to put each device in.
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*
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* Walk the dpm_locked list. Suspend each device and move it
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* to the dpm_off list.
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*
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* (For historical reasons, if it returns -EAGAIN, that used to mean
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* that the device would be called again with interrupts disabled.
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* These days, we use the "suspend_late()" callback for that, so we
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* print a warning and consider it an error).
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*/
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static int dpm_suspend(pm_message_t state)
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{
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int error = 0;
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mutex_lock(&dpm_list_mtx);
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while (!list_empty(&dpm_locked)) {
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struct list_head *entry = dpm_locked.prev;
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struct device *dev = to_device(entry);
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list_del_init(&dev->power.entry);
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mutex_unlock(&dpm_list_mtx);
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error = suspend_device(dev, state);
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if (error) {
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printk(KERN_ERR "Could not suspend device %s: "
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"error %d%s\n",
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kobject_name(&dev->kobj),
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error,
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(error == -EAGAIN ?
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" (please convert to suspend_late)" :
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""));
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mutex_lock(&dpm_list_mtx);
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if (list_empty(&dev->power.entry))
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list_add(&dev->power.entry, &dpm_locked);
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mutex_unlock(&dpm_list_mtx);
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break;
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}
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mutex_lock(&dpm_list_mtx);
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if (list_empty(&dev->power.entry))
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list_add(&dev->power.entry, &dpm_off);
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}
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mutex_unlock(&dpm_list_mtx);
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return error;
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}
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/**
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* lock_all_devices - Acquire every device's semaphore
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*
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* Go through the dpm_active list. Carefully lock each device's
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* semaphore and put it in on the dpm_locked list.
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*/
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static void lock_all_devices(void)
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{
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mutex_lock(&dpm_list_mtx);
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while (!list_empty(&dpm_active)) {
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struct list_head *entry = dpm_active.next;
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struct device *dev = to_device(entry);
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/* Required locking order is dev->sem first,
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* then dpm_list_mutex. Hence this awkward code.
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*/
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get_device(dev);
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mutex_unlock(&dpm_list_mtx);
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down(&dev->sem);
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mutex_lock(&dpm_list_mtx);
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if (list_empty(entry))
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up(&dev->sem); /* Device was removed */
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else
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list_move_tail(entry, &dpm_locked);
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put_device(dev);
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}
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mutex_unlock(&dpm_list_mtx);
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}
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/**
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* device_suspend - Save state and stop all devices in system.
|
|
*
|
|
* Prevent new devices from being registered, then lock all devices
|
|
* and suspend them.
|
|
*/
|
|
int device_suspend(pm_message_t state)
|
|
{
|
|
int error;
|
|
|
|
might_sleep();
|
|
down_write(&pm_sleep_rwsem);
|
|
lock_all_devices();
|
|
error = dpm_suspend(state);
|
|
if (error)
|
|
device_resume();
|
|
return error;
|
|
}
|
|
EXPORT_SYMBOL_GPL(device_suspend);
|
|
|
|
void __suspend_report_result(const char *function, void *fn, int ret)
|
|
{
|
|
if (ret) {
|
|
printk(KERN_ERR "%s(): ", function);
|
|
print_fn_descriptor_symbol("%s() returns ", (unsigned long)fn);
|
|
printk("%d\n", ret);
|
|
}
|
|
}
|
|
EXPORT_SYMBOL_GPL(__suspend_report_result);
|