aboutsummaryrefslogtreecommitdiff
path: root/kernel/power/main.c
blob: 873228c71dabdf700abcf2e6c19dcb3cc96315b7 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
/*
 * kernel/power/main.c - PM subsystem core functionality.
 *
 * Copyright (c) 2003 Patrick Mochel
 * Copyright (c) 2003 Open Source Development Lab
 * 
 * This file is released under the GPLv2
 *
 */

#include <linux/suspend.h>
#include <linux/kobject.h>
#include <linux/string.h>
#include <linux/delay.h>
#include <linux/errno.h>
#include <linux/init.h>
#include <linux/pm.h>
#include <linux/console.h>
#include <linux/cpu.h>
#include <linux/resume-trace.h>

#include "power.h"

/*This is just an arbitrary number */
#define FREE_PAGE_NUMBER (100)

DECLARE_MUTEX(pm_sem);

struct pm_ops *pm_ops;
suspend_disk_method_t pm_disk_mode = PM_DISK_SHUTDOWN;

/**
 *	pm_set_ops - Set the global power method table. 
 *	@ops:	Pointer to ops structure.
 */

void pm_set_ops(struct pm_ops * ops)
{
	down(&pm_sem);
	pm_ops = ops;
	up(&pm_sem);
}


/**
 *	suspend_prepare - Do prep work before entering low-power state.
 *	@state:		State we're entering.
 *
 *	This is common code that is called for each state that we're 
 *	entering. Allocate a console, stop all processes, then make sure
 *	the platform can enter the requested state.
 */

static int suspend_prepare(suspend_state_t state)
{
	int error;
	unsigned int free_pages;

	if (!pm_ops || !pm_ops->enter)
		return -EPERM;

	pm_prepare_console();

	error = disable_nonboot_cpus();
	if (error)
		goto Enable_cpu;

	if (freeze_processes()) {
		error = -EAGAIN;
		goto Thaw;
	}

	if ((free_pages = nr_free_pages()) < FREE_PAGE_NUMBER) {
		pr_debug("PM: free some memory\n");
		shrink_all_memory(FREE_PAGE_NUMBER - free_pages);
		if (nr_free_pages() < FREE_PAGE_NUMBER) {
			error = -ENOMEM;
			printk(KERN_ERR "PM: No enough memory\n");
			goto Thaw;
		}
	}

	if (pm_ops->prepare) {
		if ((error = pm_ops->prepare(state)))
			goto Thaw;
	}

	suspend_console();
	if ((error = device_suspend(PMSG_SUSPEND))) {
		printk(KERN_ERR "Some devices failed to suspend\n");
		goto Finish;
	}
	return 0;
 Finish:
	if (pm_ops->finish)
		pm_ops->finish(state);
 Thaw:
	thaw_processes();
 Enable_cpu:
	enable_nonboot_cpus();
	pm_restore_console();
	return error;
}


int suspend_enter(suspend_state_t state)
{
	int error = 0;
	unsigned long flags;

	local_irq_save(flags);

	if ((error = device_power_down(PMSG_SUSPEND))) {
		printk(KERN_ERR "Some devices failed to power down\n");
		goto Done;
	}
	error = pm_ops->enter(state);
	device_power_up();
 Done:
	local_irq_restore(flags);
	return error;
}


/**
 *	suspend_finish - Do final work before exiting suspend sequence.
 *	@state:		State we're coming out of.
 *
 *	Call platform code to clean up, restart processes, and free the 
 *	console that we've allocated. This is not called for suspend-to-disk.
 */

static void suspend_finish(suspend_state_t state)
{
	device_resume();
	resume_console();
	thaw_processes();
	enable_nonboot_cpus();
	if (pm_ops && pm_ops->finish)
		pm_ops->finish(state);
	pm_restore_console();
}




static const char * const pm_states[PM_SUSPEND_MAX] = {
	[PM_SUSPEND_STANDBY]	= "standby",
	[PM_SUSPEND_MEM]	= "mem",
#ifdef CONFIG_SOFTWARE_SUSPEND
	[PM_SUSPEND_DISK]	= "disk",
#endif
};

static inline int valid_state(suspend_state_t state)
{
	/* Suspend-to-disk does not really need low-level support.
	 * It can work with reboot if needed. */
	if (state == PM_SUSPEND_DISK)
		return 1;

	if (pm_ops && pm_ops->valid && !pm_ops->valid(state))
		return 0;
	return 1;
}


/**
 *	enter_state - Do common work of entering low-power state.
 *	@state:		pm_state structure for state we're entering.
 *
 *	Make sure we're the only ones trying to enter a sleep state. Fail
 *	if someone has beat us to it, since we don't want anything weird to
 *	happen when we wake up.
 *	Then, do the setup for suspend, enter the state, and cleaup (after
 *	we've woken up).
 */

static int enter_state(suspend_state_t state)
{
	int error;

	if (!valid_state(state))
		return -ENODEV;
	if (down_trylock(&pm_sem))
		return -EBUSY;

	if (state == PM_SUSPEND_DISK) {
		error = pm_suspend_disk();
		goto Unlock;
	}

	pr_debug("PM: Preparing system for %s sleep\n", pm_states[state]);
	if ((error = suspend_prepare(state)))
		goto Unlock;

	pr_debug("PM: Entering %s sleep\n", pm_states[state]);
	error = suspend_enter(state);

	pr_debug("PM: Finishing wakeup.\n");
	suspend_finish(state);
 Unlock:
	up(&pm_sem);
	return error;
}

/*
 * This is main interface to the outside world. It needs to be
 * called from process context.
 */
int software_suspend(void)
{
	return enter_state(PM_SUSPEND_DISK);
}


/**
 *	pm_suspend - Externally visible function for suspending system.
 *	@state:		Enumarted value of state to enter.
 *
 *	Determine whether or not value is within range, get state 
 *	structure, and enter (above).
 */

int pm_suspend(suspend_state_t state)
{
	if (state > PM_SUSPEND_ON && state <= PM_SUSPEND_MAX)
		return enter_state(state);
	return -EINVAL;
}



decl_subsys(power,NULL,NULL);


/**
 *	state - control system power state.
 *
 *	show() returns what states are supported, which is hard-coded to
 *	'standby' (Power-On Suspend), 'mem' (Suspend-to-RAM), and
 *	'disk' (Suspend-to-Disk).
 *
 *	store() accepts one of those strings, translates it into the 
 *	proper enumerated value, and initiates a suspend transition.
 */

static ssize_t state_show(struct subsystem * subsys, char * buf)
{
	int i;
	char * s = buf;

	for (i = 0; i < PM_SUSPEND_MAX; i++) {
		if (pm_states[i] && valid_state(i))
			s += sprintf(s,"%s ", pm_states[i]);
	}
	s += sprintf(s,"\n");
	return (s - buf);
}

static ssize_t state_store(struct subsystem * subsys, const char * buf, size_t n)
{
	suspend_state_t state = PM_SUSPEND_STANDBY;
	const char * const *s;
	char *p;
	int error;
	int len;

	p = memchr(buf, '\n', n);
	len = p ? p - buf : n;

	for (s = &pm_states[state]; state < PM_SUSPEND_MAX; s++, state++) {
		if (*s && !strncmp(buf, *s, len))
			break;
	}
	if (state < PM_SUSPEND_MAX && *s)
		error = enter_state(state);
	else
		error = -EINVAL;
	return error ? error : n;
}

power_attr(state);

#ifdef CONFIG_PM_TRACE
int pm_trace_enabled;

static ssize_t pm_trace_show(struct subsystem * subsys, char * buf)
{
	return sprintf(buf, "%d\n", pm_trace_enabled);
}

static ssize_t
pm_trace_store(struct subsystem * subsys, const char * buf, size_t n)
{
	int val;

	if (sscanf(buf, "%d", &val) == 1) {
		pm_trace_enabled = !!val;
		return n;
	}
	return -EINVAL;
}

power_attr(pm_trace);

static struct attribute * g[] = {
	&state_attr.attr,
	&pm_trace_attr.attr,
	NULL,
};
#else
static struct attribute * g[] = {
	&state_attr.attr,
	NULL,
};
#endif /* CONFIG_PM_TRACE */

static struct attribute_group attr_group = {
	.attrs = g,
};


static int __init pm_init(void)
{
	int error = subsystem_register(&power_subsys);
	if (!error)
		error = sysfs_create_group(&power_subsys.kset.kobj,&attr_group);
	return error;
}

core_initcall(pm_init);