2 * suspend.c - Functions for putting devices to sleep.
4 * Copyright (c) 2003 Patrick Mochel
5 * Copyright (c) 2003 Open Source Development Labs
7 * This file is released under the GPLv2
11 #include <linux/device.h>
12 #include <linux/kallsyms.h>
18 * The entries in the dpm_active list are in a depth first order, simply
19 * because children are guaranteed to be discovered after parents, and
20 * are inserted at the back of the list on discovery.
22 * All list on the suspend path are done in reverse order, so we operate
23 * on the leaves of the device tree (or forests, depending on how you want
24 * to look at it ;) first. As nodes are removed from the back of the list,
25 * they are inserted into the front of their destintation lists.
27 * Things are the reverse on the resume path - iterations are done in
28 * forward order, and nodes are inserted at the back of their destination
29 * lists. This way, the ancestors will be accessed before their descendents.
32 static inline char *suspend_verb(u32 event)
35 case PM_EVENT_SUSPEND: return "suspend";
36 case PM_EVENT_FREEZE: return "freeze";
37 default: return "(unknown suspend event)";
43 * suspend_device - Save state of one device.
45 * @state: Power state device is entering.
48 int suspend_device(struct device * dev, pm_message_t state)
53 if (dev->power.power_state.event) {
54 dev_dbg(dev, "PM: suspend %d-->%d\n",
55 dev->power.power_state.event, state.event);
57 if (dev->power.pm_parent
58 && dev->power.pm_parent->power.power_state.event) {
60 "PM: suspend %d->%d, parent %s already %d\n",
61 dev->power.power_state.event, state.event,
62 dev->power.pm_parent->bus_id,
63 dev->power.pm_parent->power.power_state.event);
66 dev->power.prev_state = dev->power.power_state;
68 if (dev->class && dev->class->suspend && !dev->power.power_state.event) {
69 dev_dbg(dev, "class %s%s\n",
70 suspend_verb(state.event),
71 ((state.event == PM_EVENT_SUSPEND)
72 && device_may_wakeup(dev))
76 error = dev->class->suspend(dev, state);
77 suspend_report_result(dev->class->suspend, error);
80 if (!error && dev->bus && dev->bus->suspend && !dev->power.power_state.event) {
81 dev_dbg(dev, "%s%s\n",
82 suspend_verb(state.event),
83 ((state.event == PM_EVENT_SUSPEND)
84 && device_may_wakeup(dev))
88 error = dev->bus->suspend(dev, state);
89 suspend_report_result(dev->bus->suspend, error);
97 * This is called with interrupts off, only a single CPU
98 * running. We can't do down() on a semaphore (and we don't
99 * need the protection)
101 static int suspend_device_late(struct device *dev, pm_message_t state)
105 if (dev->power.power_state.event) {
106 dev_dbg(dev, "PM: suspend_late %d-->%d\n",
107 dev->power.power_state.event, state.event);
110 if (dev->bus && dev->bus->suspend_late && !dev->power.power_state.event) {
111 dev_dbg(dev, "LATE %s%s\n",
112 suspend_verb(state.event),
113 ((state.event == PM_EVENT_SUSPEND)
114 && device_may_wakeup(dev))
118 error = dev->bus->suspend_late(dev, state);
119 suspend_report_result(dev->bus->suspend_late, error);
125 * device_prepare_suspend - save state and prepare to suspend
127 * NOTE! Devices cannot detach at this point - not only do we
128 * hold the device list semaphores over the whole prepare, but
129 * the whole point is to do non-invasive preparatory work, not
130 * the actual suspend.
132 int device_prepare_suspend(pm_message_t state)
139 list_for_each_entry_reverse(dev, &dpm_active, power.entry) {
140 if (!dev->bus || !dev->bus->suspend_prepare)
142 error = dev->bus->suspend_prepare(dev, state);
152 * device_suspend - Save state and stop all devices in system.
153 * @state: Power state to put each device in.
155 * Walk the dpm_active list, call ->suspend() for each device, and move
156 * it to the dpm_off list.
158 * (For historical reasons, if it returns -EAGAIN, that used to mean
159 * that the device would be called again with interrupts disabled.
160 * These days, we use the "suspend_late()" callback for that, so we
161 * print a warning and consider it an error).
163 * If we get a different error, try and back out.
165 * If we hit a failure with any of the devices, call device_resume()
166 * above to bring the suspended devices back to life.
170 int device_suspend(pm_message_t state)
176 while (!list_empty(&dpm_active) && error == 0) {
177 struct list_head * entry = dpm_active.prev;
178 struct device * dev = to_device(entry);
183 error = suspend_device(dev, state);
187 /* Check if the device got removed */
188 if (!list_empty(&dev->power.entry)) {
189 /* Move it to the dpm_off list */
191 list_move(&dev->power.entry, &dpm_off);
194 printk(KERN_ERR "Could not suspend device %s: "
196 kobject_name(&dev->kobj), error,
197 error == -EAGAIN ? " (please convert to suspend_late)" : "");
208 EXPORT_SYMBOL_GPL(device_suspend);
211 * device_power_down - Shut down special devices.
212 * @state: Power state to enter.
214 * Walk the dpm_off_irq list, calling ->power_down() for each device that
215 * couldn't power down the device with interrupts enabled. When we're
216 * done, power down system devices.
219 int device_power_down(pm_message_t state)
224 while (!list_empty(&dpm_off)) {
225 struct list_head * entry = dpm_off.prev;
227 dev = to_device(entry);
228 error = suspend_device_late(dev, state);
231 list_move(&dev->power.entry, &dpm_off_irq);
234 error = sysdev_suspend(state);
238 printk(KERN_ERR "Could not power down device %s: "
239 "error %d\n", kobject_name(&dev->kobj), error);
244 EXPORT_SYMBOL_GPL(device_power_down);
246 void __suspend_report_result(const char *function, void *fn, int ret)
249 printk(KERN_ERR "%s(): ", function);
250 print_fn_descriptor_symbol("%s() returns ", (unsigned long)fn);
254 EXPORT_SYMBOL_GPL(__suspend_report_result);