projects/linux·blob v2.6.21 · refs

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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/pm.h>
19#include <linux/console.h>
20#include <linux/cpu.h>
21#include <linux/resume-trace.h>
22#include <linux/freezer.h>
23#include <linux/vmstat.h>
24
25#include "power.h"
26
27/*This is just an arbitrary number */
28#define FREE_PAGE_NUMBER (100)
29
30DEFINE_MUTEX(pm_mutex);
31
32struct pm_ops *pm_ops;
33suspend_disk_method_t pm_disk_mode = PM_DISK_PLATFORM;
34
35/**
36 * pm_set_ops - Set the global power method table.
37 * @ops: Pointer to ops structure.
38 */
39
40void pm_set_ops(struct pm_ops * ops)
41{
42 mutex_lock(&pm_mutex);
43 pm_ops = ops;
44 mutex_unlock(&pm_mutex);
45}
46
47static inline void pm_finish(suspend_state_t state)
48{
49 if (pm_ops->finish)
50 pm_ops->finish(state);
51}
52
53/**
54 * suspend_prepare - Do prep work before entering low-power state.
55 * @state: State we're entering.
56 *
57 * This is common code that is called for each state that we're
58 * entering. Allocate a console, stop all processes, then make sure
59 * the platform can enter the requested state.
60 */
61
62static int suspend_prepare(suspend_state_t state)
63{
64 int error;
65 unsigned int free_pages;
66
67 if (!pm_ops || !pm_ops->enter)
68 return -EPERM;
69
70 pm_prepare_console();
71
72 if (freeze_processes()) {
73 error = -EAGAIN;
74 goto Thaw;
75 }
76
77 if ((free_pages = global_page_state(NR_FREE_PAGES))
78 < FREE_PAGE_NUMBER) {
79 pr_debug("PM: free some memory\n");
80 shrink_all_memory(FREE_PAGE_NUMBER - free_pages);
81 if (nr_free_pages() < FREE_PAGE_NUMBER) {
82 error = -ENOMEM;
83 printk(KERN_ERR "PM: No enough memory\n");
84 goto Thaw;
85 }
86 }
87
88 if (pm_ops->prepare) {
89 if ((error = pm_ops->prepare(state)))
90 goto Thaw;
91 }
92
93 suspend_console();
94 error = device_suspend(PMSG_SUSPEND);
95 if (error) {
96 printk(KERN_ERR "Some devices failed to suspend\n");
97 goto Resume_devices;
98 }
99 error = disable_nonboot_cpus();
100 if (!error)
101 return 0;
102
103 enable_nonboot_cpus();
104 Resume_devices:
105 pm_finish(state);
106 device_resume();
107 resume_console();
108 Thaw:
109 thaw_processes();
110 pm_restore_console();
111 return error;
112}
113
114
115int suspend_enter(suspend_state_t state)
116{
117 int error = 0;
118 unsigned long flags;
119
120 local_irq_save(flags);
121
122 if ((error = device_power_down(PMSG_SUSPEND))) {
123 printk(KERN_ERR "Some devices failed to power down\n");
124 goto Done;
125 }
126 error = pm_ops->enter(state);
127 device_power_up();
128 Done:
129 local_irq_restore(flags);
130 return error;
131}
132
133
134/**
135 * suspend_finish - Do final work before exiting suspend sequence.
136 * @state: State we're coming out of.
137 *
138 * Call platform code to clean up, restart processes, and free the
139 * console that we've allocated. This is not called for suspend-to-disk.
140 */
141
142static void suspend_finish(suspend_state_t state)
143{
144 enable_nonboot_cpus();
145 pm_finish(state);
146 device_resume();
147 resume_console();
148 thaw_processes();
149 pm_restore_console();
150}
151
152
153
154
155static const char * const pm_states[PM_SUSPEND_MAX] = {
156 [PM_SUSPEND_STANDBY] = "standby",
157 [PM_SUSPEND_MEM] = "mem",
158#ifdef CONFIG_SOFTWARE_SUSPEND
159 [PM_SUSPEND_DISK] = "disk",
160#endif
161};
162
163static inline int valid_state(suspend_state_t state)
164{
165 /* Suspend-to-disk does not really need low-level support.
166 * It can work with reboot if needed. */
167 if (state == PM_SUSPEND_DISK)
168 return 1;
169
170 /* all other states need lowlevel support and need to be
171 * valid to the lowlevel implementation, no valid callback
172 * implies that all are valid. */
173 if (!pm_ops || (pm_ops->valid && !pm_ops->valid(state)))
174 return 0;
175 return 1;
176}
177
178
179/**
180 * enter_state - Do common work of entering low-power state.
181 * @state: pm_state structure for state we're entering.
182 *
183 * Make sure we're the only ones trying to enter a sleep state. Fail
184 * if someone has beat us to it, since we don't want anything weird to
185 * happen when we wake up.
186 * Then, do the setup for suspend, enter the state, and cleaup (after
187 * we've woken up).
188 */
189
190static int enter_state(suspend_state_t state)
191{
192 int error;
193
194 if (!valid_state(state))
195 return -ENODEV;
196 if (!mutex_trylock(&pm_mutex))
197 return -EBUSY;
198
199 if (state == PM_SUSPEND_DISK) {
200 error = pm_suspend_disk();
201 goto Unlock;
202 }
203
204 pr_debug("PM: Preparing system for %s sleep\n", pm_states[state]);
205 if ((error = suspend_prepare(state)))
206 goto Unlock;
207
208 pr_debug("PM: Entering %s sleep\n", pm_states[state]);
209 error = suspend_enter(state);
210
211 pr_debug("PM: Finishing wakeup.\n");
212 suspend_finish(state);
213 Unlock:
214 mutex_unlock(&pm_mutex);
215 return error;
216}
217
218/*
219 * This is main interface to the outside world. It needs to be
220 * called from process context.
221 */
222int software_suspend(void)
223{
224 return enter_state(PM_SUSPEND_DISK);
225}
226
227
228/**
229 * pm_suspend - Externally visible function for suspending system.
230 * @state: Enumarted value of state to enter.
231 *
232 * Determine whether or not value is within range, get state
233 * structure, and enter (above).
234 */
235
236int pm_suspend(suspend_state_t state)
237{
238 if (state > PM_SUSPEND_ON && state <= PM_SUSPEND_MAX)
239 return enter_state(state);
240 return -EINVAL;
241}
242
243EXPORT_SYMBOL(pm_suspend);
244
245decl_subsys(power,NULL,NULL);
246
247
248/**
249 * state - control system power state.
250 *
251 * show() returns what states are supported, which is hard-coded to
252 * 'standby' (Power-On Suspend), 'mem' (Suspend-to-RAM), and
253 * 'disk' (Suspend-to-Disk).
254 *
255 * store() accepts one of those strings, translates it into the
256 * proper enumerated value, and initiates a suspend transition.
257 */
258
259static ssize_t state_show(struct subsystem * subsys, char * buf)
260{
261 int i;
262 char * s = buf;
263
264 for (i = 0; i < PM_SUSPEND_MAX; i++) {
265 if (pm_states[i] && valid_state(i))
266 s += sprintf(s,"%s ", pm_states[i]);
267 }
268 s += sprintf(s,"\n");
269 return (s - buf);
270}
271
272static ssize_t state_store(struct subsystem * subsys, const char * buf, size_t n)
273{
274 suspend_state_t state = PM_SUSPEND_STANDBY;
275 const char * const *s;
276 char *p;
277 int error;
278 int len;
279
280 p = memchr(buf, '\n', n);
281 len = p ? p - buf : n;
282
283 for (s = &pm_states[state]; state < PM_SUSPEND_MAX; s++, state++) {
284 if (*s && !strncmp(buf, *s, len))
285 break;
286 }
287 if (state < PM_SUSPEND_MAX && *s)
288 error = enter_state(state);
289 else
290 error = -EINVAL;
291 return error ? error : n;
292}
293
294power_attr(state);
295
296#ifdef CONFIG_PM_TRACE
297int pm_trace_enabled;
298
299static ssize_t pm_trace_show(struct subsystem * subsys, char * buf)
300{
301 return sprintf(buf, "%d\n", pm_trace_enabled);
302}
303
304static ssize_t
305pm_trace_store(struct subsystem * subsys, const char * buf, size_t n)
306{
307 int val;
308
309 if (sscanf(buf, "%d", &val) == 1) {
310 pm_trace_enabled = !!val;
311 return n;
312 }
313 return -EINVAL;
314}
315
316power_attr(pm_trace);
317
318static struct attribute * g[] = {
319 &state_attr.attr,
320 &pm_trace_attr.attr,
321 NULL,
322};
323#else
324static struct attribute * g[] = {
325 &state_attr.attr,
326 NULL,
327};
328#endif /* CONFIG_PM_TRACE */
329
330static struct attribute_group attr_group = {
331 .attrs = g,
332};
333
334
335static int __init pm_init(void)
336{
337 int error = subsystem_register(&power_subsys);
338 if (!error)
339 error = sysfs_create_group(&power_subsys.kset.kobj,&attr_group);
340 return error;
341}
342
343core_initcall(pm_init);