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144 lines
3.6 KiB
144 lines
3.6 KiB
/*
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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 "power.h"
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extern int sysdev_suspend(pm_message_t state);
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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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/**
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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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dev_dbg(dev, "suspending\n");
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dev->power.prev_state = dev->power.power_state;
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if (dev->bus && dev->bus->suspend && !dev->power.power_state)
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error = dev->bus->suspend(dev, state);
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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 dpm_off.
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* Check the return value for each. If it returns 0, then we move the
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* the device to the dpm_off list. If it returns -EAGAIN, we move it to
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* the dpm_off_irq list. 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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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 or dpm_off_irq list */
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if (!error) {
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list_del(&dev->power.entry);
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list_add(&dev->power.entry, &dpm_off);
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} else if (error == -EAGAIN) {
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list_del(&dev->power.entry);
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list_add(&dev->power.entry, &dpm_off_irq);
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error = 0;
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}
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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\n", kobject_name(&dev->kobj), error);
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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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list_for_each_entry_reverse(dev, &dpm_off_irq, power.entry) {
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if ((error = suspend_device(dev, state)))
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break;
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}
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if (error)
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goto Error;
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if ((error = sysdev_suspend(state)))
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goto Error;
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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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