Attachment 306389 Details for Bug 442494 – drivers/base/power/main.c

drivers/base/power/main.c

main.c (text/plain), 11.80 KB, created by Patrick Klingemann on 2008-05-22 14:48:51 UTC

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Creator: Patrick Klingemann

Created: 2008-05-22 14:48:51 UTC

Size: 11.80 KB

patch

obsolete

>/*
> * 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 different set of lists than the global subsystem list are used to
> * keep track of power info because we use different lists to hold
> * devices based on what stage of the power management process they
> * are in. The power domain dependencies may also 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_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_off);
>static LIST_HEAD(dpm_off_irq);
>static LIST_HEAD(dpm_destroy);
>
>static DEFINE_MUTEX(dpm_list_mtx);
>
>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",
>		 dev->bus ? dev->bus->name : "No Bus",
>		 kobject_name(&dev->kobj));
>	mutex_lock(&dpm_list_mtx);
>	list_add_tail(&dev->power.entry, &dpm_active);
>	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);
>	dpm_sysfs_remove(dev);
>	list_del_init(&dev->power.entry);
>	mutex_unlock(&dpm_list_mtx);
>}
>
>/**
> *	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);
>}
>EXPORT_SYMBOL_GPL(device_pm_schedule_removal);
>
>/**
> *	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_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);
>	}
>
>	if (!error && dev->type && dev->type->resume) {
>		dev_dbg(dev,"resuming\n");
>		error = dev->type->resume(dev);
>	}
>
>	if (!error && dev->class && dev->class->resume) {
>		dev_dbg(dev,"class resume\n");
>		error = dev->class->resume(dev);
>	}
>
>	up(&dev->sem);
>
>	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.
> *
> *	Take devices from the dpm_off_list, resume them,
> *	and put them on the dpm_locked list.
> */
>static void dpm_resume(void)
>{
>	mutex_lock(&dpm_list_mtx);
>	while(!list_empty(&dpm_off)) {
>		struct list_head *entry = dpm_off.next;
>		struct device *dev = to_device(entry);
>
>		list_move_tail(entry, &dpm_active);
>		mutex_unlock(&dpm_list_mtx);
>		resume_device(dev);
>		mutex_lock(&dpm_list_mtx);
>	}
>	mutex_unlock(&dpm_list_mtx);
>}
>
>/**
> *	unregister_dropped_devices - Unregister devices scheduled for removal
> *
> *	Unregister all devices on the dpm_destroy list.
> */
>static void unregister_dropped_devices(void)
>{
>	mutex_lock(&dpm_list_mtx);
>	while (!list_empty(&dpm_destroy)) {
>		struct list_head *entry = dpm_destroy.next;
>		struct device *dev = to_device(entry);
>
>		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_resume - Restore state of each device in system.
> *
> *	Resume all the devices, unlock them all, and allow new
> *	devices to be registered once again.
> */
>void device_resume(void)
>{
>	might_sleep();
>	dpm_resume();
>	unregister_dropped_devices();
>	up_write(&pm_sleep_rwsem);
>}
>EXPORT_SYMBOL_GPL(device_resume);
>
>
>/*------------------------- Suspend routines -------------------------*/
>
>static inline char *suspend_verb(u32 event)
>{
>	switch (event) {
>	case PM_EVENT_SUSPEND:	return "suspend";
>	case PM_EVENT_FREEZE:	return "freeze";
>	case PM_EVENT_PRETHAW:	return "prethaw";
>	default:		return "(unknown suspend event)";
>	}
>}
>
>static void
>suspend_device_dbg(struct device *dev, pm_message_t state, char *info)
>{
>	dev_dbg(dev, "%s%s%s\n", info, suspend_verb(state.event),
>		((state.event == PM_EVENT_SUSPEND) && device_may_wakeup(dev)) ?
>		", may wakeup" : "");
>}
>
>/**
> *	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;
>
>	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);
>
>		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);
>			break;
>		}
>		if (!list_empty(&dev->power.entry))
>			list_move(&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.
> */
>static 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);
>	}
>
>	if (dev->class && dev->class->suspend) {
>		suspend_device_dbg(dev, state, "class ");
>		error = dev->class->suspend(dev, state);
>		suspend_report_result(dev->class->suspend, error);
>	}
>
>	if (!error && dev->type && dev->type->suspend) {
>		suspend_device_dbg(dev, state, "type ");
>		error = dev->type->suspend(dev, state);
>		suspend_report_result(dev->type->suspend, error);
>	}
>
>	if (!error && dev->bus && dev->bus->suspend) {
>		suspend_device_dbg(dev, state, "");
>		error = dev->bus->suspend(dev, state);
>		suspend_report_result(dev->bus->suspend, error);
>	}
>
>	up(&dev->sem);
>
>	return error;
>}
>
>/**
> *	dpm_suspend - Suspend every device.
> *	@state:	Power state to put each device in.
> *
> *	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).
> */
>static int dpm_suspend(pm_message_t state)
>{
>	int error = 0;
>
>	mutex_lock(&dpm_list_mtx);
>	while (!list_empty(&dpm_active)) {
>		struct list_head *entry = dpm_active.prev;
>		struct device *dev = to_device(entry);
>
>		mutex_unlock(&dpm_list_mtx);
>		error = suspend_device(dev, state);
>		mutex_lock(&dpm_list_mtx);
>		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)" :
>					""));
>			break;
>		}
>		if (!list_empty(&dev->power.entry))
>			list_move(&dev->power.entry, &dpm_off);
>	}
>	mutex_unlock(&dpm_list_mtx);
>
>	return error;
>}
>
>/**
> *	device_suspend - Save state and stop all devices in system.
> *	@state: new power management state
> *
> *	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);
>	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);

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Attachments on bug 442494: 306389