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 <linux/kallsyms.h>
13#include <linux/pm.h>
14#include "../base.h"
15#include "power.h"
16
17/*
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.
21 *
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.
26 *
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.
30 */
31
32static inline char *suspend_verb(u32 event)
33{
34	switch (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)";
39	}
40}
41
42
43/**
44 *	suspend_device - Save state of one device.
45 *	@dev:	Device.
46 *	@state:	Power state device is entering.
47 */
48
49int suspend_device(struct device * dev, pm_message_t state)
50{
51	int error = 0;
52
53	down(&dev->sem);
54	if (dev->power.power_state.event) {
55		dev_dbg(dev, "PM: suspend %d-->%d\n",
56			dev->power.power_state.event, state.event);
57	}
58	if (dev->power.pm_parent
59			&& dev->power.pm_parent->power.power_state.event) {
60		dev_err(dev,
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);
65	}
66
67	dev->power.prev_state = dev->power.power_state;
68
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))
74				? ", may wakeup"
75				: ""
76			);
77		error = dev->class->suspend(dev, state);
78		suspend_report_result(dev->class->suspend, error);
79	}
80
81	if (!error && dev->type && dev->type->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))
86				? ", may wakeup"
87				: ""
88			);
89		error = dev->type->suspend(dev, state);
90		suspend_report_result(dev->type->suspend, error);
91	}
92
93	if (!error && dev->bus && dev->bus->suspend && !dev->power.power_state.event) {
94		dev_dbg(dev, "%s%s\n",
95			suspend_verb(state.event),
96			((state.event == PM_EVENT_SUSPEND)
97					&& device_may_wakeup(dev))
98				? ", may wakeup"
99				: ""
100			);
101		error = dev->bus->suspend(dev, state);
102		suspend_report_result(dev->bus->suspend, error);
103	}
104	up(&dev->sem);
105	return error;
106}
107
108
109/*
110 * This is called with interrupts off, only a single CPU
111 * running. We can't do down() on a semaphore (and we don't
112 * need the protection)
113 */
114static int suspend_device_late(struct device *dev, pm_message_t state)
115{
116	int error = 0;
117
118	if (dev->bus && dev->bus->suspend_late && !dev->power.power_state.event) {
119		dev_dbg(dev, "LATE %s%s\n",
120			suspend_verb(state.event),
121			((state.event == PM_EVENT_SUSPEND)
122					&& device_may_wakeup(dev))
123				? ", may wakeup"
124				: ""
125			);
126		error = dev->bus->suspend_late(dev, state);
127		suspend_report_result(dev->bus->suspend_late, error);
128	}
129	return error;
130}
131
132/**
133 *	device_suspend - Save state and stop all devices in system.
134 *	@state:		Power state to put each device in.
135 *
136 *	Walk the dpm_active list, call ->suspend() for each device, and move
137 *	it to the dpm_off list.
138 *
139 *	(For historical reasons, if it returns -EAGAIN, that used to mean
140 *	that the device would be called again with interrupts disabled.
141 *	These days, we use the "suspend_late()" callback for that, so we
142 *	print a warning and consider it an error).
143 *
144 *	If we get a different error, try and back out.
145 *
146 *	If we hit a failure with any of the devices, call device_resume()
147 *	above to bring the suspended devices back to life.
148 *
149 */
150
151int device_suspend(pm_message_t state)
152{
153	int error = 0;
154
155	might_sleep();
156	down(&dpm_sem);
157	down(&dpm_list_sem);
158	while (!list_empty(&dpm_active) && error == 0) {
159		struct list_head * entry = dpm_active.prev;
160		struct device * dev = to_device(entry);
161
162		get_device(dev);
163		up(&dpm_list_sem);
164
165		error = suspend_device(dev, state);
166
167		down(&dpm_list_sem);
168
169		/* Check if the device got removed */
170		if (!list_empty(&dev->power.entry)) {
171			/* Move it to the dpm_off list */
172			if (!error)
173				list_move(&dev->power.entry, &dpm_off);
174		}
175		if (error)
176			printk(KERN_ERR "Could not suspend device %s: "
177				"error %d%s\n",
178				kobject_name(&dev->kobj), error,
179				error == -EAGAIN ? " (please convert to suspend_late)" : "");
180		put_device(dev);
181	}
182	up(&dpm_list_sem);
183	if (error)
184		dpm_resume();
185
186	up(&dpm_sem);
187	return error;
188}
189
190EXPORT_SYMBOL_GPL(device_suspend);
191
192/**
193 *	device_power_down - Shut down special devices.
194 *	@state:		Power state to enter.
195 *
196 *	Walk the dpm_off_irq list, calling ->power_down() for each device that
197 *	couldn't power down the device with interrupts enabled. When we're
198 *	done, power down system devices.
199 */
200
201int device_power_down(pm_message_t state)
202{
203	int error = 0;
204	struct device * dev;
205
206	while (!list_empty(&dpm_off)) {
207		struct list_head * entry = dpm_off.prev;
208
209		dev = to_device(entry);
210		error = suspend_device_late(dev, state);
211		if (error)
212			goto Error;
213		list_move(&dev->power.entry, &dpm_off_irq);
214	}
215
216	error = sysdev_suspend(state);
217 Done:
218	return error;
219 Error:
220	printk(KERN_ERR "Could not power down device %s: "
221		"error %d\n", kobject_name(&dev->kobj), error);
222	dpm_power_up();
223	goto Done;
224}
225
226EXPORT_SYMBOL_GPL(device_power_down);
227
228void __suspend_report_result(const char *function, void *fn, int ret)
229{
230	if (ret) {
231		printk(KERN_ERR "%s(): ", function);
232		print_fn_descriptor_symbol("%s() returns ", (unsigned long)fn);
233		printk("%d\n", ret);
234	}
235}
236EXPORT_SYMBOL_GPL(__suspend_report_result);
237