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 - Save state of one device.
46 * @state: Power state device is entering.
49 int suspend_device(struct device
* dev
, pm_message_t state
)
54 if (dev
->power
.power_state
.event
) {
55 dev_dbg(dev
, "PM: suspend %d-->%d\n",
56 dev
->power
.power_state
.event
, state
.event
);
58 if (dev
->power
.pm_parent
59 && dev
->power
.pm_parent
->power
.power_state
.event
) {
61 "PM: suspend %d->%d, parent %s already %d\n",
62 dev
->power
.power_state
.event
, state
.event
,
63 dev
->power
.pm_parent
->bus_id
,
64 dev
->power
.pm_parent
->power
.power_state
.event
);
67 dev
->power
.prev_state
= dev
->power
.power_state
;
69 if (dev
->class && dev
->class->suspend
&& !dev
->power
.power_state
.event
) {
70 dev_dbg(dev
, "class %s%s\n",
71 suspend_verb(state
.event
),
72 ((state
.event
== PM_EVENT_SUSPEND
)
73 && device_may_wakeup(dev
))
77 error
= dev
->class->suspend(dev
, state
);
78 suspend_report_result(dev
->class->suspend
, error
);
81 if (!error
&& dev
->bus
&& dev
->bus
->suspend
&& !dev
->power
.power_state
.event
) {
82 dev_dbg(dev
, "%s%s\n",
83 suspend_verb(state
.event
),
84 ((state
.event
== PM_EVENT_SUSPEND
)
85 && device_may_wakeup(dev
))
89 error
= dev
->bus
->suspend(dev
, state
);
90 suspend_report_result(dev
->bus
->suspend
, error
);
98 * This is called with interrupts off, only a single CPU
99 * running. We can't do down() on a semaphore (and we don't
100 * need the protection)
102 static int suspend_device_late(struct device
*dev
, pm_message_t state
)
106 if (dev
->bus
&& dev
->bus
->suspend_late
&& !dev
->power
.power_state
.event
) {
107 dev_dbg(dev
, "LATE %s%s\n",
108 suspend_verb(state
.event
),
109 ((state
.event
== PM_EVENT_SUSPEND
)
110 && device_may_wakeup(dev
))
114 error
= dev
->bus
->suspend_late(dev
, state
);
115 suspend_report_result(dev
->bus
->suspend_late
, error
);
121 * device_suspend - Save state and stop all devices in system.
122 * @state: Power state to put each device in.
124 * Walk the dpm_active list, call ->suspend() for each device, and move
125 * it to the dpm_off list.
127 * (For historical reasons, if it returns -EAGAIN, that used to mean
128 * that the device would be called again with interrupts disabled.
129 * These days, we use the "suspend_late()" callback for that, so we
130 * print a warning and consider it an error).
132 * If we get a different error, try and back out.
134 * If we hit a failure with any of the devices, call device_resume()
135 * above to bring the suspended devices back to life.
139 int device_suspend(pm_message_t state
)
146 while (!list_empty(&dpm_active
) && error
== 0) {
147 struct list_head
* entry
= dpm_active
.prev
;
148 struct device
* dev
= to_device(entry
);
153 error
= suspend_device(dev
, state
);
157 /* Check if the device got removed */
158 if (!list_empty(&dev
->power
.entry
)) {
159 /* Move it to the dpm_off list */
161 list_move(&dev
->power
.entry
, &dpm_off
);
164 printk(KERN_ERR
"Could not suspend device %s: "
166 kobject_name(&dev
->kobj
), error
,
167 error
== -EAGAIN
? " (please convert to suspend_late)" : "");
178 EXPORT_SYMBOL_GPL(device_suspend
);
181 * device_power_down - Shut down special devices.
182 * @state: Power state to enter.
184 * Walk the dpm_off_irq list, calling ->power_down() for each device that
185 * couldn't power down the device with interrupts enabled. When we're
186 * done, power down system devices.
189 int device_power_down(pm_message_t state
)
194 while (!list_empty(&dpm_off
)) {
195 struct list_head
* entry
= dpm_off
.prev
;
197 dev
= to_device(entry
);
198 error
= suspend_device_late(dev
, state
);
201 list_move(&dev
->power
.entry
, &dpm_off_irq
);
204 error
= sysdev_suspend(state
);
208 printk(KERN_ERR
"Could not power down device %s: "
209 "error %d\n", kobject_name(&dev
->kobj
), error
);
214 EXPORT_SYMBOL_GPL(device_power_down
);
216 void __suspend_report_result(const char *function
, void *fn
, int ret
)
219 printk(KERN_ERR
"%s(): ", function
);
220 print_fn_descriptor_symbol("%s() returns ", (unsigned long)fn
);
224 EXPORT_SYMBOL_GPL(__suspend_report_result
);