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![Linus Torvalds](/assets/img/avatar_default.png)
Everybody wants to pass it a function pointer, and in fact, that is what you _must_ pass it for it to make sense (since it knows that ia64 and ppc64 use descriptors for function pointers and fetches the actual address from there). So don't make the argument be a 'unsigned long' and force everybody to add a cast. Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
425 lines
10 KiB
C
425 lines
10 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_off);
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static LIST_HEAD(dpm_off_irq);
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static DEFINE_MUTEX(dpm_list_mtx);
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/* 'true' if all devices have been suspended, protected by dpm_list_mtx */
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static bool all_sleeping;
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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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int device_pm_add(struct device *dev)
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{
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int error;
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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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if ((dev->parent && dev->parent->power.sleeping) || all_sleeping) {
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if (dev->parent->power.sleeping)
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dev_warn(dev, "parent %s is sleeping\n",
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dev->parent->bus_id);
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else
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dev_warn(dev, "all devices are sleeping\n");
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WARN_ON(true);
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}
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error = dpm_sysfs_add(dev);
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if (!error)
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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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return error;
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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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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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}
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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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down(&dev->sem);
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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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up(&dev->sem);
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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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all_sleeping = false;
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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_active);
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dev->power.sleeping = false;
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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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* 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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}
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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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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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break;
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}
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if (!list_empty(&dev->power.entry))
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list_move(&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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static 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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down(&dev->sem);
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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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up(&dev->sem);
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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_active)) {
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struct list_head *entry = dpm_active.prev;
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struct device *dev = to_device(entry);
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WARN_ON(dev->parent && dev->parent->power.sleeping);
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dev->power.sleeping = true;
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mutex_unlock(&dpm_list_mtx);
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error = suspend_device(dev, state);
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mutex_lock(&dpm_list_mtx);
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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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dev->power.sleeping = false;
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break;
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}
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if (!list_empty(&dev->power.entry))
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list_move(&dev->power.entry, &dpm_off);
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}
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if (!error)
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all_sleeping = true;
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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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* device_suspend - Save state and stop all devices in system.
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* @state: new power management state
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*
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* Prevent new devices from being registered, then lock all devices
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* and suspend them.
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*/
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int device_suspend(pm_message_t state)
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{
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int error;
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might_sleep();
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error = dpm_suspend(state);
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if (error)
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device_resume();
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return error;
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}
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EXPORT_SYMBOL_GPL(device_suspend);
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void __suspend_report_result(const char *function, void *fn, int ret)
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{
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if (ret) {
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printk(KERN_ERR "%s(): ", function);
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print_fn_descriptor_symbol("%s returns ", fn);
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printk("%d\n", ret);
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}
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}
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EXPORT_SYMBOL_GPL(__suspend_report_result);
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