Automatic merge of rsync://rsync.kernel.org/pub/scm/linux/kernel/git/gregkh/driver...
[linux-2.6] / drivers / base / power / suspend.c
1 /*
2  * suspend.c - Functions for putting devices to sleep.
3  *
4  * Copyright (c) 2003 Patrick Mochel
5  * Copyright (c) 2003 Open Source Development Labs
6  *
7  * This file is released under the GPLv2
8  *
9  */
10
11 #include <linux/device.h>
12 #include "power.h"
13
14 extern int sysdev_suspend(pm_message_t state);
15
16 /*
17  * The entries in the dpm_active list are in a depth first order, simply
18  * because children are guaranteed to be discovered after parents, and
19  * are inserted at the back of the list on discovery.
20  *
21  * All list on the suspend path are done in reverse order, so we operate
22  * on the leaves of the device tree (or forests, depending on how you want
23  * to look at it ;) first. As nodes are removed from the back of the list,
24  * they are inserted into the front of their destintation lists.
25  *
26  * Things are the reverse on the resume path - iterations are done in
27  * forward order, and nodes are inserted at the back of their destination
28  * lists. This way, the ancestors will be accessed before their descendents.
29  */
30
31
32 /**
33  *      suspend_device - Save state of one device.
34  *      @dev:   Device.
35  *      @state: Power state device is entering.
36  */
37
38 int suspend_device(struct device * dev, pm_message_t state)
39 {
40         int error = 0;
41
42         if (dev->power.power_state) {
43                 dev_dbg(dev, "PM: suspend %d-->%d\n",
44                         dev->power.power_state, state);
45         }
46         if (dev->power.pm_parent
47                         && dev->power.pm_parent->power.power_state) {
48                 dev_err(dev,
49                         "PM: suspend %d->%d, parent %s already %d\n",
50                         dev->power.power_state, state,
51                         dev->power.pm_parent->bus_id,
52                         dev->power.pm_parent->power.power_state);
53         }
54
55         dev->power.prev_state = dev->power.power_state;
56
57         if (dev->bus && dev->bus->suspend && !dev->power.power_state) {
58                 dev_dbg(dev, "suspending\n");
59                 error = dev->bus->suspend(dev, state);
60         }
61
62         return error;
63 }
64
65
66 /**
67  *      device_suspend - Save state and stop all devices in system.
68  *      @state:         Power state to put each device in.
69  *
70  *      Walk the dpm_active list, call ->suspend() for each device, and move
71  *      it to dpm_off.
72  *      Check the return value for each. If it returns 0, then we move the
73  *      the device to the dpm_off list. If it returns -EAGAIN, we move it to
74  *      the dpm_off_irq list. If we get a different error, try and back out.
75  *
76  *      If we hit a failure with any of the devices, call device_resume()
77  *      above to bring the suspended devices back to life.
78  *
79  */
80
81 int device_suspend(pm_message_t state)
82 {
83         int error = 0;
84
85         down(&dpm_sem);
86         down(&dpm_list_sem);
87         while (!list_empty(&dpm_active) && error == 0) {
88                 struct list_head * entry = dpm_active.prev;
89                 struct device * dev = to_device(entry);
90
91                 get_device(dev);
92                 up(&dpm_list_sem);
93
94                 error = suspend_device(dev, state);
95
96                 down(&dpm_list_sem);
97
98                 /* Check if the device got removed */
99                 if (!list_empty(&dev->power.entry)) {
100                         /* Move it to the dpm_off or dpm_off_irq list */
101                         if (!error) {
102                                 list_del(&dev->power.entry);
103                                 list_add(&dev->power.entry, &dpm_off);
104                         } else if (error == -EAGAIN) {
105                                 list_del(&dev->power.entry);
106                                 list_add(&dev->power.entry, &dpm_off_irq);
107                                 error = 0;
108                         }
109                 }
110                 if (error)
111                         printk(KERN_ERR "Could not suspend device %s: "
112                                 "error %d\n", kobject_name(&dev->kobj), error);
113                 put_device(dev);
114         }
115         up(&dpm_list_sem);
116         if (error)
117                 dpm_resume();
118         up(&dpm_sem);
119         return error;
120 }
121
122 EXPORT_SYMBOL_GPL(device_suspend);
123
124
125 /**
126  *      device_power_down - Shut down special devices.
127  *      @state:         Power state to enter.
128  *
129  *      Walk the dpm_off_irq list, calling ->power_down() for each device that
130  *      couldn't power down the device with interrupts enabled. When we're
131  *      done, power down system devices.
132  */
133
134 int device_power_down(pm_message_t state)
135 {
136         int error = 0;
137         struct device * dev;
138
139         list_for_each_entry_reverse(dev, &dpm_off_irq, power.entry) {
140                 if ((error = suspend_device(dev, state)))
141                         break;
142         }
143         if (error)
144                 goto Error;
145         if ((error = sysdev_suspend(state)))
146                 goto Error;
147  Done:
148         return error;
149  Error:
150         printk(KERN_ERR "Could not power down device %s: "
151                 "error %d\n", kobject_name(&dev->kobj), error);
152         dpm_power_up();
153         goto Done;
154 }
155
156 EXPORT_SYMBOL_GPL(device_power_down);
157