PM: Acquire device locks on suspend

	switch (action) {

	case CPU_UP_PREPARE:

	case CPU_UP_PREPARE_FROZEN:

		err = cpuid_device_create(cpu);

		break;

	case CPU_UP_CANCELED:

	case CPU_UP_CANCELED_FROZEN:

	case CPU_DEAD:

	case CPU_DEAD_FROZEN:

		cpuid_device_destroy(cpu);

		break;

	case CPU_UP_CANCELED_FROZEN:

		destroy_suspended_device(cpuid_class, MKDEV(CPUID_MAJOR, cpu));

		break;

	}

	return err ? NOTIFY_BAD : NOTIFY_OK;

}

	switch (action) {

	case CPU_UP_PREPARE:

	case CPU_UP_PREPARE_FROZEN:

		err = msr_device_create(cpu);

		break;

	case CPU_UP_CANCELED:

	case CPU_UP_CANCELED_FROZEN:

	case CPU_DEAD:

	case CPU_DEAD_FROZEN:

		msr_device_destroy(cpu);

		break;

	case CPU_UP_CANCELED_FROZEN:

		destroy_suspended_device(msr_class, MKDEV(MSR_MAJOR, cpu));

		break;

	}

	return err ? NOTIFY_BAD : NOTIFY_OK;

}

{

	struct device *parent = NULL;

	struct class_interface *class_intf;

	int error = -EINVAL;

	int error;

	error = pm_sleep_lock();

	if (error) {

		dev_warn(dev, "Suspicious %s during suspend\n", __FUNCTION__);

		dump_stack();

		return error;

	}

	dev = get_device(dev);

	if (!dev || !strlen(dev->bus_id))

	if (!dev || !strlen(dev->bus_id)) {

		error = -EINVAL;

		goto Error;

	}

	pr_debug("DEV: registering device: ID = '%s'\n", dev->bus_id);

	}

 Done:

	put_device(dev);

	pm_sleep_unlock();

	return error;

 BusError:

	device_pm_remove(dev);

	struct device * parent = dev->parent;

	struct class_interface *class_intf;

	device_pm_remove(dev);

	if (parent)

		klist_del(&dev->knode_parent);

	if (MAJOR(dev->devt))

	if (dev->bus)

		blocking_notifier_call_chain(&dev->bus->bus_notifier,

					     BUS_NOTIFY_DEL_DEVICE, dev);

	device_pm_remove(dev);

	kobject_uevent(&dev->kobj, KOBJ_REMOVE);

	kobject_del(&dev->kobj);

	if (parent)

EXPORT_SYMBOL_GPL(device_create);

/**

 * device_destroy - removes a device that was created with device_create()

 * find_device - finds a device that was created with device_create()

 * @class: pointer to the struct class that this device was registered with

 * @devt: the dev_t of the device that was previously registered

 *

 * This call unregisters and cleans up a device that was created with a

 * call to device_create().

 */

void device_destroy(struct class *class, dev_t devt)

static struct device *find_device(struct class *class, dev_t devt)

{

	struct device *dev = NULL;

	struct device *dev_tmp;

		}

	}

	up(&class->sem);

	return dev;

}

/**

 * device_destroy - removes a device that was created with device_create()

 * @class: pointer to the struct class that this device was registered with

 * @devt: the dev_t of the device that was previously registered

 *

 * This call unregisters and cleans up a device that was created with a

 * call to device_create().

 */

void device_destroy(struct class *class, dev_t devt)

{

	struct device *dev;

	dev = find_device(class, devt);

	if (dev)

		device_unregister(dev);

}

EXPORT_SYMBOL_GPL(device_destroy);

#ifdef CONFIG_PM_SLEEP

/**

 * destroy_suspended_device - asks the PM core to remove a suspended device

 * @class: pointer to the struct class that this device was registered with

 * @devt: the dev_t of the device that was previously registered

 *

 * This call notifies the PM core of the necessity to unregister a suspended

 * device created with a call to device_create() (devices cannot be

 * unregistered directly while suspended, since the PM core holds their

 * semaphores at that time).

 *

 * It can only be called within the scope of a system sleep transition.  In

 * practice this means it has to be directly or indirectly invoked either by

 * a suspend or resume method, or by the PM core (e.g. via

 * disable_nonboot_cpus() or enable_nonboot_cpus()).

 */

void destroy_suspended_device(struct class *class, dev_t devt)

{

	struct device *dev;

	dev = find_device(class, devt);

	if (dev)

		device_pm_schedule_removal(dev);

}

EXPORT_SYMBOL_GPL(destroy_suspended_device);

#endif /* CONFIG_PM_SLEEP */

/**

 * device_rename - renames a device

 * @dev: the pointer to the struct device to be renamed

#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_active 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.

 *

 * All the other lists are kept in the same order, for consistency.

 * However the lists aren't always traversed in the same order.

 * Semaphores must be acquired from the top (i.e., front) down

 * and released in the opposite order.  Devices must be suspended

 * from the bottom (i.e., end) up and resumed in the opposite order.

 * That way no parent will be suspended while it still has an active

 * child.

 *

 * 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_active);

static LIST_HEAD(dpm_locked);

static LIST_HEAD(dpm_off);

static LIST_HEAD(dpm_off_irq);

static LIST_HEAD(dpm_destroy);

static DEFINE_MUTEX(dpm_mtx);

static DEFINE_MUTEX(dpm_list_mtx);

int (*platform_enable_wakeup)(struct device *dev, int is_on);

static DECLARE_RWSEM(pm_sleep_rwsem);

int (*platform_enable_wakeup)(struct device *dev, int is_on);

/**

 *	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",

	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)

{

	/*

	 * If this function is called during a suspend, it will be blocked,

	 * because we're holding the device's semaphore at that time, which may

	 * lead to a deadlock.  In that case we want to print a warning.

	 * However, it may also be called by unregister_dropped_devices() with

	 * the device's semaphore released, in which case the warning should

	 * not be printed.

	 */

	if (down_trylock(&dev->sem)) {

		if (down_read_trylock(&pm_sleep_rwsem)) {

			/* No suspend in progress, wait on dev->sem */

			down(&dev->sem);

			up_read(&pm_sleep_rwsem);

		} else {

			/* Suspend in progress, we may deadlock */

			dev_warn(dev, "Suspicious %s during suspend\n",

				__FUNCTION__);

			dump_stack();

			/* The user has been warned ... */

			down(&dev->sem);

		}

	}

	pr_debug("PM: Removing info for %s:%s\n",

		 dev->bus ? dev->bus->name : "No Bus",

		 kobject_name(&dev->kobj));

	dpm_sysfs_remove(dev);

	list_del_init(&dev->power.entry);

	mutex_unlock(&dpm_list_mtx);

	up(&dev->sem);

}

/**

 *	device_pm_schedule_removal - schedule the removal of a suspended device

 *	@dev:	Device to destroy

 *

 *	Moves the device to the dpm_destroy list for further processing by

 *	unregister_dropped_devices().

 */

void device_pm_schedule_removal(struct device *dev)

{

	pr_debug("PM: Preparing for removal: %s:%s\n",

		dev->bus ? dev->bus->name : "No Bus",

		kobject_name(&dev->kobj));

	mutex_lock(&dpm_list_mtx);

	list_move_tail(&dev->power.entry, &dpm_destroy);

	mutex_unlock(&dpm_list_mtx);

}

/**

 *	pm_sleep_lock - mutual exclusion for registration and suspend

 *

 *	Returns 0 if no suspend is underway and device registration

 *	may proceed, otherwise -EBUSY.

 */

int pm_sleep_lock(void)

{

	if (down_read_trylock(&pm_sleep_rwsem))

		return 0;

	return -EBUSY;

}

/**

 *	pm_sleep_unlock - mutual exclusion for registration and suspend

 *

 *	This routine undoes the effect of device_pm_add_lock

 *	when a device's registration is complete.

 */

void pm_sleep_unlock(void)

{

	up_read(&pm_sleep_rwsem);

}

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

/**

 *	resume_device - Restore state for one device.

 *	resume_device_early - Power on one device (early resume).

 *	@dev:	Device.

 *

 *	Must be called with interrupts disabled.

 */

static int resume_device_early(struct device *dev)

{

	int error = 0;

	TRACE_DEVICE(dev);

	TRACE_RESUME(0);

	if (dev->bus && dev->bus->resume_early) {

		dev_dbg(dev, "EARLY resume\n");

		error = dev->bus->resume_early(dev);

	}

	TRACE_RESUME(error);

	return error;

}

/**

 *	dpm_power_up - Power on all regular (non-sysdev) devices.

 *

 *	Walk the dpm_off_irq list and power each device up. This

 *	is used for devices that required they be powered down with

 *	interrupts disabled. As devices are powered on, they are moved

 *	to the dpm_off list.

 *

 *	Must be called with interrupts disabled and only one CPU running.

 */

static void dpm_power_up(void)

{

	while (!list_empty(&dpm_off_irq)) {

		struct list_head *entry = dpm_off_irq.next;

		struct device *dev = to_device(entry);

		list_move_tail(entry, &dpm_off);

		resume_device_early(dev);

	}

}

/**

 *	device_power_up - Turn on all devices that need special attention.

 *

 *	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(void)

{

	sysdev_resume();

	dpm_power_up();

}

EXPORT_SYMBOL_GPL(device_power_up);

/**

 *	resume_device - Restore state for one device.

 *	@dev:	Device.

 *

 */

static int resume_device(struct device *dev)

{

	int error = 0;

	TRACE_DEVICE(dev);

	TRACE_RESUME(0);

	down(&dev->sem);

	if (dev->bus && dev->bus->resume) {

		dev_dbg(dev,"resuming\n");

		error = dev->bus->resume(dev);

		error = dev->class->resume(dev);

	}

	up(&dev->sem);

	TRACE_RESUME(error);

	return error;

}

static int resume_device_early(struct device * dev)

{

	int error = 0;

	TRACE_DEVICE(dev);

	TRACE_RESUME(0);

	if (dev->bus && dev->bus->resume_early) {

		dev_dbg(dev,"EARLY resume\n");

		error = dev->bus->resume_early(dev);

	}

	TRACE_RESUME(error);

	return error;

}

/*

/**

 *	dpm_resume - Resume every device.

 *

 *	Resume the devices that have either not gone through

 *	the late suspend, or that did go through it but also

 * went through the early resume

 *	went through the early resume.

 *

 *	Take devices from the dpm_off_list, resume them,

 *	and put them on the dpm_locked list.

 */

static void dpm_resume(void)

{

		struct list_head *entry = dpm_off.next;

		struct device *dev = to_device(entry);

		get_device(dev);

		list_move_tail(entry, &dpm_active);

		list_move_tail(entry, &dpm_locked);

		mutex_unlock(&dpm_list_mtx);

		resume_device(dev);

		mutex_lock(&dpm_list_mtx);

		put_device(dev);

	}

	mutex_unlock(&dpm_list_mtx);

}

/**

 *	device_resume - Restore state of each device in system.

 *	unlock_all_devices - Release each device's semaphore

 *

 *	Walk the dpm_off list, remove each entry, resume the device,

 *	then add it to the dpm_active list.

 *	Go through the dpm_off list.  Put each device on the dpm_active

 *	list and unlock it.

 */

void device_resume(void)

static void unlock_all_devices(void)

{

	might_sleep();

	mutex_lock(&dpm_mtx);

	dpm_resume();

	mutex_unlock(&dpm_mtx);

}

EXPORT_SYMBOL_GPL(device_resume);

	mutex_lock(&dpm_list_mtx);

	while (!list_empty(&dpm_locked)) {

		struct list_head *entry = dpm_locked.prev;

		struct device *dev = to_device(entry);

		list_move(entry, &dpm_active);

		up(&dev->sem);

	}

	mutex_unlock(&dpm_list_mtx);

}

/**

 *	dpm_power_up - Power on some devices.

 *

 *	Walk the dpm_off_irq list and power each device up. This

 *	is used for devices that required they be powered down with

 *	interrupts disabled. As devices are powered on, they are moved

 *	to the dpm_active list.

 *	unregister_dropped_devices - Unregister devices scheduled for removal

 *

 *	Interrupts must be disabled when calling this.

 *	Unregister all devices on the dpm_destroy list.

 */

static void dpm_power_up(void)

static void unregister_dropped_devices(void)

{

	while(!list_empty(&dpm_off_irq)) {

		struct list_head * entry = dpm_off_irq.next;

	mutex_lock(&dpm_list_mtx);

	while (!list_empty(&dpm_destroy)) {

		struct list_head *entry = dpm_destroy.next;

		struct device *dev = to_device(entry);

		list_move_tail(entry, &dpm_off);

		resume_device_early(dev);

		up(&dev->sem);

		mutex_unlock(&dpm_list_mtx);

		/* This also removes the device from the list */

		device_unregister(dev);

		mutex_lock(&dpm_list_mtx);

	}

	mutex_unlock(&dpm_list_mtx);

}

/**

 *	device_power_up - Turn on all devices that need special attention.

 *	device_resume - Restore state of each device in system.

 *

 *	Power on system devices then devices that required we shut them down

 *	with interrupts disabled.

 *	Called with interrupts disabled.

 *	Resume all the devices, unlock them all, and allow new

 *	devices to be registered once again.

 */

void device_power_up(void)

void device_resume(void)

{

	sysdev_resume();

	dpm_power_up();

	might_sleep();

	dpm_resume();

	unlock_all_devices();

	unregister_dropped_devices();

	up_write(&pm_sleep_rwsem);

}

EXPORT_SYMBOL_GPL(device_power_up);

EXPORT_SYMBOL_GPL(device_resume);

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

/*

 * The entries in the dpm_active 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.

 *

 * All list on the suspend path are done in reverse order, so we operate

 * on the leaves of the device tree (or forests, depending on how you want

 * to look at it ;) first. As nodes are removed from the back of the list,

 * they are inserted into the front of their destintation lists.

 *

 * Things are the reverse on the resume path - iterations are done in

 * forward order, and nodes are inserted at the back of their destination

 * lists. This way, the ancestors will be accessed before their descendents.

 */

static inline char *suspend_verb(u32 event)

{

	switch (event) {

	}

}

static void

suspend_device_dbg(struct device *dev, pm_message_t state, char *info)

{

}

/**

 *	suspend_device - Save state of one device.

 *	suspend_device_late - Shut down one device (late suspend).

 *	@dev:	Device.

 *	@state:	Power state device is entering.

 *

 *	This is called with interrupts off and only a single CPU running.

 */

static int suspend_device_late(struct device *dev, pm_message_t state)

{

	int error = 0;

static int suspend_device(struct device * dev, pm_message_t state)

	if (dev->bus && dev->bus->suspend_late) {

		suspend_device_dbg(dev, state, "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:		Power state to enter.

 *

 *	Power down devices that require interrupts to be disabled

 *	and move them from the dpm_off list to the dpm_off_irq list.

 *	Then power down system devices.

 *

 *	Must be called with interrupts disabled and only one CPU running.

 */

int device_power_down(pm_message_t state)

{

	int error = 0;

	while (!list_empty(&dpm_off)) {

		struct list_head *entry = dpm_off.prev;

		struct device *dev = to_device(entry);

		list_del_init(&dev->power.entry);

		error = suspend_device_late(dev, state);

		if (error) {

			printk(KERN_ERR "Could not power down device %s: "

					"error %d\n",

					kobject_name(&dev->kobj), error);

			if (list_empty(&dev->power.entry))

				list_add(&dev->power.entry, &dpm_off);

			break;

		}

		if (list_empty(&dev->power.entry))

			list_add(&dev->power.entry, &dpm_off_irq);

	}

	if (!error)

		error = sysdev_suspend(state);

	if (error)

		dpm_power_up();

	return error;

}

EXPORT_SYMBOL_GPL(device_power_down);

/**

 *	suspend_device - Save state of one device.

 *	@dev:	Device.

 *	@state:	Power state device is entering.

 */

int suspend_device(struct device *dev, pm_message_t state)

{

	int error = 0;

	down(&dev->sem);

	if (dev->power.power_state.event) {

		dev_dbg(dev, "PM: suspend %d-->%d\n",

			dev->power.power_state.event, state.event);

		error = dev->bus->suspend(dev, state);

		suspend_report_result(dev->bus->suspend, error);

	}

	up(&dev->sem);

	return error;

}

/*

 * This is called with interrupts off, only a single CPU

 * running. We can't acquire a mutex or semaphore (and we don't

 * need the protection)

 */

static int suspend_device_late(struct device *dev, pm_message_t state)

{

	int error = 0;

	if (dev->bus && dev->bus->suspend_late) {

		suspend_device_dbg(dev, state, "LATE ");

		error = dev->bus->suspend_late(dev, state);

		suspend_report_result(dev->bus->suspend_late, error);

	}

	return error;

}

/**

 *	device_suspend - Save state and stop all devices in system.

 *	dpm_suspend - Suspend every device.

 *	@state:	Power state to put each device in.

 *

 *	Walk the dpm_active list, call ->suspend() for each device, and move

 *	it to the dpm_off list.

 *	Walk the dpm_locked list.  Suspend each device and move it

 *	to the dpm_off list.

 *

 *	(For historical reasons, if it returns -EAGAIN, that used to mean

 *	that the device would be called again with interrupts disabled.

 *	These days, we use the "suspend_late()" callback for that, so we

 *	print a warning and consider it an error).

 *

 *	If we get a different error, try and back out.

 *

 *	If we hit a failure with any of the devices, call device_resume()

 *	above to bring the suspended devices back to life.

 *

 */

int device_suspend(pm_message_t state)

static int dpm_suspend(pm_message_t state)

{

	int error = 0;

	might_sleep();

	mutex_lock(&dpm_mtx);

	mutex_lock(&dpm_list_mtx);

	while (!list_empty(&dpm_active) && error == 0) {

		struct list_head * entry = dpm_active.prev;

	while (!list_empty(&dpm_locked)) {

		struct list_head *entry = dpm_locked.prev;

		struct device *dev = to_device(entry);

		get_device(dev);

		list_del_init(&dev->power.entry);

		mutex_unlock(&dpm_list_mtx);

		error = suspend_device(dev, state);

		mutex_lock(&dpm_list_mtx);

		/* Check if the device got removed */

		if (!list_empty(&dev->power.entry)) {

			/* Move it to the dpm_off list */

			if (!error)

				list_move(&dev->power.entry, &dpm_off);

		}

		if (error)

		if (error) {

			printk(KERN_ERR "Could not suspend device %s: "

					"error %d%s\n",

				kobject_name(&dev->kobj), error,

				error == -EAGAIN ? " (please convert to suspend_late)" : "");

		put_device(dev);

					kobject_name(&dev->kobj),

					error,

					(error == -EAGAIN ?

					" (please convert to suspend_late)" :

					""));

			mutex_lock(&dpm_list_mtx);

			if (list_empty(&dev->power.entry))

				list_add(&dev->power.entry, &dpm_locked);

			mutex_unlock(&dpm_list_mtx);

			break;

		}

		mutex_lock(&dpm_list_mtx);

		if (list_empty(&dev->power.entry))

			list_add(&dev->power.entry, &dpm_off);

	}