mirror of https://gitee.com/openkylin/linux.git
237 lines
6.1 KiB
C
237 lines
6.1 KiB
C
/*
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* suspend.c - Functions for putting devices to sleep.
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*
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* Copyright (c) 2003 Patrick Mochel
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* Copyright (c) 2003 Open Source Development Labs
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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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#include <linux/device.h>
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#include <linux/kallsyms.h>
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#include <linux/pm.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 list on the suspend path are done in reverse order, so we operate
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* on the leaves of the device tree (or forests, depending on how you want
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* to look at it ;) first. As nodes are removed from the back of the list,
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* they are inserted into the front of their destintation lists.
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*
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* Things are the reverse on the resume path - iterations are done in
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* forward order, and nodes are inserted at the back of their destination
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* lists. This way, the ancestors will be accessed before their descendents.
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*/
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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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/**
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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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down(&dev->sem);
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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->power.pm_parent
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&& dev->power.pm_parent->power.power_state.event) {
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dev_err(dev,
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"PM: suspend %d->%d, parent %s already %d\n",
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dev->power.power_state.event, state.event,
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dev->power.pm_parent->bus_id,
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dev->power.pm_parent->power.power_state.event);
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}
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dev->power.prev_state = dev->power.power_state;
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if (dev->class && dev->class->suspend && !dev->power.power_state.event) {
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dev_dbg(dev, "class %s%s\n",
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suspend_verb(state.event),
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((state.event == PM_EVENT_SUSPEND)
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&& device_may_wakeup(dev))
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? ", may wakeup"
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: ""
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);
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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 && !dev->power.power_state.event) {
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dev_dbg(dev, "%s%s\n",
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suspend_verb(state.event),
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((state.event == PM_EVENT_SUSPEND)
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&& device_may_wakeup(dev))
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? ", may wakeup"
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: ""
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);
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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 && !dev->power.power_state.event) {
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dev_dbg(dev, "%s%s\n",
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suspend_verb(state.event),
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((state.event == PM_EVENT_SUSPEND)
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&& device_may_wakeup(dev))
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? ", may wakeup"
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: ""
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);
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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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* This is called with interrupts off, only a single CPU
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* running. We can't do down() on a semaphore (and we don't
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* need the protection)
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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 && !dev->power.power_state.event) {
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dev_dbg(dev, "LATE %s%s\n",
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suspend_verb(state.event),
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((state.event == PM_EVENT_SUSPEND)
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&& device_may_wakeup(dev))
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? ", may wakeup"
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: ""
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);
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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_suspend - Save state and stop all devices in system.
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* @state: Power state to put each device in.
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*
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* Walk the dpm_active list, call ->suspend() for each device, and move
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* it 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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* If we get a different error, try and back out.
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*
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* If we hit a failure with any of the devices, call device_resume()
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* above to bring the suspended devices back to life.
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*
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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 = 0;
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might_sleep();
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down(&dpm_sem);
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down(&dpm_list_sem);
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while (!list_empty(&dpm_active) && error == 0) {
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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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get_device(dev);
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up(&dpm_list_sem);
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error = suspend_device(dev, state);
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down(&dpm_list_sem);
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/* Check if the device got removed */
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if (!list_empty(&dev->power.entry)) {
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/* Move it to the dpm_off list */
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if (!error)
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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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printk(KERN_ERR "Could not suspend device %s: "
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"error %d%s\n",
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kobject_name(&dev->kobj), error,
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error == -EAGAIN ? " (please convert to suspend_late)" : "");
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put_device(dev);
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}
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up(&dpm_list_sem);
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if (error)
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dpm_resume();
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up(&dpm_sem);
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return error;
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}
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EXPORT_SYMBOL_GPL(device_suspend);
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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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* Walk the dpm_off_irq list, calling ->power_down() for each device that
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* couldn't power down the device with interrupts enabled. When we're
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* done, power down system devices.
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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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struct device * dev;
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while (!list_empty(&dpm_off)) {
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struct list_head * entry = dpm_off.prev;
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dev = to_device(entry);
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error = suspend_device_late(dev, state);
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if (error)
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goto Error;
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list_move(&dev->power.entry, &dpm_off_irq);
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}
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error = sysdev_suspend(state);
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Done:
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return error;
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Error:
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printk(KERN_ERR "Could not power down device %s: "
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"error %d\n", kobject_name(&dev->kobj), error);
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dpm_power_up();
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goto Done;
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}
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EXPORT_SYMBOL_GPL(device_power_down);
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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 ", (unsigned long)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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