1/*
2 * kernel/power/main.c - PM subsystem core functionality.
3 *
4 * Copyright (c) 2003 Patrick Mochel
5 * Copyright (c) 2003 Open Source Development Lab
6 *
7 * This file is released under the GPLv2
8 *
9 */
10
11#include <linux/module.h>
12#include <linux/suspend.h>
13#include <linux/kobject.h>
14#include <linux/string.h>
15#include <linux/delay.h>
16#include <linux/errno.h>
17#include <linux/init.h>
18#include <linux/console.h>
19#include <linux/cpu.h>
20#include <linux/resume-trace.h>
21#include <linux/freezer.h>
22#include <linux/vmstat.h>
23
24#include "power.h"
25
26/*This is just an arbitrary number */
27#define FREE_PAGE_NUMBER (100)
28
29DEFINE_MUTEX(pm_mutex);
30
31struct pm_ops *pm_ops;
32
33/**
34 *	pm_set_ops - Set the global power method table.
35 *	@ops:	Pointer to ops structure.
36 */
37
38void pm_set_ops(struct pm_ops * ops)
39{
40	mutex_lock(&pm_mutex);
41	pm_ops = ops;
42	mutex_unlock(&pm_mutex);
43}
44
45/**
46 * pm_valid_only_mem - generic memory-only valid callback
47 *
48 * pm_ops drivers that implement mem suspend only and only need
49 * to check for that in their .valid callback can use this instead
50 * of rolling their own .valid callback.
51 */
52int pm_valid_only_mem(suspend_state_t state)
53{
54	return state == PM_SUSPEND_MEM;
55}
56
57
58static inline void pm_finish(suspend_state_t state)
59{
60	if (pm_ops->finish)
61		pm_ops->finish(state);
62}
63
64/**
65 *	suspend_prepare - Do prep work before entering low-power state.
66 *	@state:		State we're entering.
67 *
68 *	This is common code that is called for each state that we're
69 *	entering. Allocate a console, stop all processes, then make sure
70 *	the platform can enter the requested state.
71 */
72
73static int suspend_prepare(suspend_state_t state)
74{
75	int error;
76	unsigned int free_pages;
77
78	if (!pm_ops || !pm_ops->enter)
79		return -EPERM;
80
81	pm_prepare_console();
82
83	if (freeze_processes()) {
84		error = -EAGAIN;
85		goto Thaw;
86	}
87
88	if ((free_pages = global_page_state(NR_FREE_PAGES))
89			< FREE_PAGE_NUMBER) {
90		pr_debug("PM: free some memory\n");
91		shrink_all_memory(FREE_PAGE_NUMBER - free_pages);
92		if (nr_free_pages() < FREE_PAGE_NUMBER) {
93			error = -ENOMEM;
94			printk(KERN_ERR "PM: No enough memory\n");
95			goto Thaw;
96		}
97	}
98
99	if (pm_ops->set_target) {
100		error = pm_ops->set_target(state);
101		if (error)
102			goto Thaw;
103	}
104	suspend_console();
105	error = device_suspend(PMSG_SUSPEND);
106	if (error) {
107		printk(KERN_ERR "Some devices failed to suspend\n");
108		goto Resume_console;
109	}
110	if (pm_ops->prepare) {
111		if ((error = pm_ops->prepare(state)))
112			goto Resume_devices;
113	}
114
115	error = disable_nonboot_cpus();
116	if (!error)
117		return 0;
118
119	enable_nonboot_cpus();
120	pm_finish(state);
121 Resume_devices:
122	device_resume();
123 Resume_console:
124	resume_console();
125 Thaw:
126	thaw_processes();
127	pm_restore_console();
128	return error;
129}
130
131/* default implementation */
132void __attribute__ ((weak)) arch_suspend_disable_irqs(void)
133{
134	local_irq_disable();
135}
136
137/* default implementation */
138void __attribute__ ((weak)) arch_suspend_enable_irqs(void)
139{
140	local_irq_enable();
141}
142
143int suspend_enter(suspend_state_t state)
144{
145	int error = 0;
146
147	arch_suspend_disable_irqs();
148	BUG_ON(!irqs_disabled());
149
150	if ((error = device_power_down(PMSG_SUSPEND))) {
151		printk(KERN_ERR "Some devices failed to power down\n");
152		goto Done;
153	}
154	error = pm_ops->enter(state);
155	device_power_up();
156 Done:
157	arch_suspend_enable_irqs();
158	BUG_ON(irqs_disabled());
159	return error;
160}
161
162
163/**
164 *	suspend_finish - Do final work before exiting suspend sequence.
165 *	@state:		State we're coming out of.
166 *
167 *	Call platform code to clean up, restart processes, and free the
168 *	console that we've allocated. This is not called for suspend-to-disk.
169 */
170
171static void suspend_finish(suspend_state_t state)
172{
173	enable_nonboot_cpus();
174	pm_finish(state);
175	device_resume();
176	resume_console();
177	thaw_processes();
178	pm_restore_console();
179}
180
181
182
183
184static const char * const pm_states[PM_SUSPEND_MAX] = {
185	[PM_SUSPEND_STANDBY]	= "standby",
186	[PM_SUSPEND_MEM]	= "mem",
187};
188
189static inline int valid_state(suspend_state_t state)
190{
191	/* All states need lowlevel support and need to be valid
192	 * to the lowlevel implementation, no valid callback
193	 * implies that none are valid. */
194	if (!pm_ops || !pm_ops->valid || !pm_ops->valid(state))
195		return 0;
196	return 1;
197}
198
199
200/**
201 *	enter_state - Do common work of entering low-power state.
202 *	@state:		pm_state structure for state we're entering.
203 *
204 *	Make sure we're the only ones trying to enter a sleep state. Fail
205 *	if someone has beat us to it, since we don't want anything weird to
206 *	happen when we wake up.
207 *	Then, do the setup for suspend, enter the state, and cleaup (after
208 *	we've woken up).
209 */
210
211static int enter_state(suspend_state_t state)
212{
213	int error;
214
215	if (!valid_state(state))
216		return -ENODEV;
217	if (!mutex_trylock(&pm_mutex))
218		return -EBUSY;
219
220	pr_debug("PM: Preparing system for %s sleep\n", pm_states[state]);
221	if ((error = suspend_prepare(state)))
222		goto Unlock;
223
224	pr_debug("PM: Entering %s sleep\n", pm_states[state]);
225	error = suspend_enter(state);
226
227	pr_debug("PM: Finishing wakeup.\n");
228	suspend_finish(state);
229 Unlock:
230	mutex_unlock(&pm_mutex);
231	return error;
232}
233
234
235/**
236 *	pm_suspend - Externally visible function for suspending system.
237 *	@state:		Enumerated value of state to enter.
238 *
239 *	Determine whether or not value is within range, get state
240 *	structure, and enter (above).
241 */
242
243int pm_suspend(suspend_state_t state)
244{
245	if (state > PM_SUSPEND_ON && state <= PM_SUSPEND_MAX)
246		return enter_state(state);
247	return -EINVAL;
248}
249
250EXPORT_SYMBOL(pm_suspend);
251
252decl_subsys(power,NULL,NULL);
253
254
255/**
256 *	state - control system power state.
257 *
258 *	show() returns what states are supported, which is hard-coded to
259 *	'standby' (Power-On Suspend), 'mem' (Suspend-to-RAM), and
260 *	'disk' (Suspend-to-Disk).
261 *
262 *	store() accepts one of those strings, translates it into the
263 *	proper enumerated value, and initiates a suspend transition.
264 */
265
266static ssize_t state_show(struct kset *kset, char *buf)
267{
268	int i;
269	char * s = buf;
270
271	for (i = 0; i < PM_SUSPEND_MAX; i++) {
272		if (pm_states[i] && valid_state(i))
273			s += sprintf(s,"%s ", pm_states[i]);
274	}
275#ifdef CONFIG_SOFTWARE_SUSPEND
276	s += sprintf(s, "%s\n", "disk");
277#else
278	if (s != buf)
279		/* convert the last space to a newline */
280		*(s-1) = '\n';
281#endif
282	return (s - buf);
283}
284
285static ssize_t state_store(struct kset *kset, const char *buf, size_t n)
286{
287	suspend_state_t state = PM_SUSPEND_STANDBY;
288	const char * const *s;
289	char *p;
290	int error;
291	int len;
292
293	p = memchr(buf, '\n', n);
294	len = p ? p - buf : n;
295
296	/* First, check if we are requested to hibernate */
297	if (len == 4 && !strncmp(buf, "disk", len)) {
298		error = hibernate();
299		return error ? error : n;
300	}
301
302	for (s = &pm_states[state]; state < PM_SUSPEND_MAX; s++, state++) {
303		if (*s && len == strlen(*s) && !strncmp(buf, *s, len))
304			break;
305	}
306	if (state < PM_SUSPEND_MAX && *s)
307		error = enter_state(state);
308	else
309		error = -EINVAL;
310	return error ? error : n;
311}
312
313power_attr(state);
314
315#ifdef CONFIG_PM_TRACE
316int pm_trace_enabled;
317
318static ssize_t pm_trace_show(struct kset *kset, char *buf)
319{
320	return sprintf(buf, "%d\n", pm_trace_enabled);
321}
322
323static ssize_t
324pm_trace_store(struct kset *kset, const char *buf, size_t n)
325{
326	int val;
327
328	if (sscanf(buf, "%d", &val) == 1) {
329		pm_trace_enabled = !!val;
330		return n;
331	}
332	return -EINVAL;
333}
334
335power_attr(pm_trace);
336
337static struct attribute * g[] = {
338	&state_attr.attr,
339	&pm_trace_attr.attr,
340	NULL,
341};
342#else
343static struct attribute * g[] = {
344	&state_attr.attr,
345	NULL,
346};
347#endif /* CONFIG_PM_TRACE */
348
349static struct attribute_group attr_group = {
350	.attrs = g,
351};
352
353
354static int __init pm_init(void)
355{
356	int error = subsystem_register(&power_subsys);
357	if (!error)
358		error = sysfs_create_group(&power_subsys.kobj,&attr_group);
359	return error;
360}
361
362core_initcall(pm_init);
363