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 case PM_EVENT_PRETHAW: return "prethaw";
38 default: return "(unknown suspend event)";
44 suspend_device_dbg(struct device *dev, pm_message_t state, char *info)
46 dev_dbg(dev, "%s%s%s\n", info, suspend_verb(state.event),
47 ((state.event == PM_EVENT_SUSPEND) && device_may_wakeup(dev)) ?
52 * suspend_device - Save state of one device.
54 * @state: Power state device is entering.
57 int suspend_device(struct device * dev, pm_message_t state)
62 if (dev->power.power_state.event) {
63 dev_dbg(dev, "PM: suspend %d-->%d\n",
64 dev->power.power_state.event, state.event);
66 if (dev->parent && dev->parent->power.power_state.event) {
68 "PM: suspend %d->%d, parent %s already %d\n",
69 dev->power.power_state.event, state.event,
71 dev->parent->power.power_state.event);
74 if (dev->class && dev->class->suspend) {
75 suspend_device_dbg(dev, state, "class ");
76 error = dev->class->suspend(dev, state);
77 suspend_report_result(dev->class->suspend, error);
80 if (!error && dev->type && dev->type->suspend) {
81 suspend_device_dbg(dev, state, "type ");
82 error = dev->type->suspend(dev, state);
83 suspend_report_result(dev->type->suspend, error);
86 if (!error && dev->bus && dev->bus->suspend) {
87 suspend_device_dbg(dev, state, "");
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 acquire a mutex or 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->bus && dev->bus->suspend_late) {
106 suspend_device_dbg(dev, state, "LATE ");
107 error = dev->bus->suspend_late(dev, state);
108 suspend_report_result(dev->bus->suspend_late, error);
114 * device_suspend - Save state and stop all devices in system.
115 * @state: Power state to put each device in.
117 * Walk the dpm_active list, call ->suspend() for each device, and move
118 * it to the dpm_off list.
120 * (For historical reasons, if it returns -EAGAIN, that used to mean
121 * that the device would be called again with interrupts disabled.
122 * These days, we use the "suspend_late()" callback for that, so we
123 * print a warning and consider it an error).
125 * If we get a different error, try and back out.
127 * If we hit a failure with any of the devices, call device_resume()
128 * above to bring the suspended devices back to life.
132 int device_suspend(pm_message_t state)
137 mutex_lock(&dpm_mtx);
138 mutex_lock(&dpm_list_mtx);
139 while (!list_empty(&dpm_active) && error == 0) {
140 struct list_head * entry = dpm_active.prev;
141 struct device * dev = to_device(entry);
144 mutex_unlock(&dpm_list_mtx);
146 error = suspend_device(dev, state);
148 mutex_lock(&dpm_list_mtx);
150 /* Check if the device got removed */
151 if (!list_empty(&dev->power.entry)) {
152 /* Move it to the dpm_off list */
154 list_move(&dev->power.entry, &dpm_off);
157 printk(KERN_ERR "Could not suspend device %s: "
159 kobject_name(&dev->kobj), error,
160 error == -EAGAIN ? " (please convert to suspend_late)" : "");
163 mutex_unlock(&dpm_list_mtx);
167 mutex_unlock(&dpm_mtx);
171 EXPORT_SYMBOL_GPL(device_suspend);
174 * device_power_down - Shut down special devices.
175 * @state: Power state to enter.
177 * Walk the dpm_off_irq list, calling ->power_down() for each device that
178 * couldn't power down the device with interrupts enabled. When we're
179 * done, power down system devices.
182 int device_power_down(pm_message_t state)
187 while (!list_empty(&dpm_off)) {
188 struct list_head * entry = dpm_off.prev;
190 dev = to_device(entry);
191 error = suspend_device_late(dev, state);
194 list_move(&dev->power.entry, &dpm_off_irq);
197 error = sysdev_suspend(state);
201 printk(KERN_ERR "Could not power down device %s: "
202 "error %d\n", kobject_name(&dev->kobj), error);
207 EXPORT_SYMBOL_GPL(device_power_down);
209 void __suspend_report_result(const char *function, void *fn, int ret)
212 printk(KERN_ERR "%s(): ", function);
213 print_fn_descriptor_symbol("%s() returns ", (unsigned long)fn);
217 EXPORT_SYMBOL_GPL(__suspend_report_result);