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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/kobject.h> |
12 | #include <linux/string.h> |
13 | #include <linux/resume-trace.h> |
14 | #include <linux/workqueue.h> |
15 | |
16 | #include "power.h" |
17 | |
18 | DEFINE_MUTEX(pm_mutex); |
19 | |
20 | #ifdef CONFIG_PM_SLEEP |
21 | |
22 | /* Routines for PM-transition notifications */ |
23 | |
24 | static BLOCKING_NOTIFIER_HEAD(pm_chain_head); |
25 | |
26 | int register_pm_notifier(struct notifier_block *nb) |
27 | { |
28 | return blocking_notifier_chain_register(&pm_chain_head, nb); |
29 | } |
30 | EXPORT_SYMBOL_GPL(register_pm_notifier); |
31 | |
32 | int unregister_pm_notifier(struct notifier_block *nb) |
33 | { |
34 | return blocking_notifier_chain_unregister(&pm_chain_head, nb); |
35 | } |
36 | EXPORT_SYMBOL_GPL(unregister_pm_notifier); |
37 | |
38 | int pm_notifier_call_chain(unsigned long val) |
39 | { |
40 | return (blocking_notifier_call_chain(&pm_chain_head, val, NULL) |
41 | == NOTIFY_BAD) ? -EINVAL : 0; |
42 | } |
43 | |
44 | /* If set, devices may be suspended and resumed asynchronously. */ |
45 | int pm_async_enabled = 1; |
46 | |
47 | static ssize_t pm_async_show(struct kobject *kobj, struct kobj_attribute *attr, |
48 | char *buf) |
49 | { |
50 | return sprintf(buf, "%d\n", pm_async_enabled); |
51 | } |
52 | |
53 | static ssize_t pm_async_store(struct kobject *kobj, struct kobj_attribute *attr, |
54 | const char *buf, size_t n) |
55 | { |
56 | unsigned long val; |
57 | |
58 | if (strict_strtoul(buf, 10, &val)) |
59 | return -EINVAL; |
60 | |
61 | if (val > 1) |
62 | return -EINVAL; |
63 | |
64 | pm_async_enabled = val; |
65 | return n; |
66 | } |
67 | |
68 | power_attr(pm_async); |
69 | |
70 | #ifdef CONFIG_PM_DEBUG |
71 | int pm_test_level = TEST_NONE; |
72 | |
73 | static const char * const pm_tests[__TEST_AFTER_LAST] = { |
74 | [TEST_NONE] = "none", |
75 | [TEST_CORE] = "core", |
76 | [TEST_CPUS] = "processors", |
77 | [TEST_PLATFORM] = "platform", |
78 | [TEST_DEVICES] = "devices", |
79 | [TEST_FREEZER] = "freezer", |
80 | }; |
81 | |
82 | static ssize_t pm_test_show(struct kobject *kobj, struct kobj_attribute *attr, |
83 | char *buf) |
84 | { |
85 | char *s = buf; |
86 | int level; |
87 | |
88 | for (level = TEST_FIRST; level <= TEST_MAX; level++) |
89 | if (pm_tests[level]) { |
90 | if (level == pm_test_level) |
91 | s += sprintf(s, "[%s] ", pm_tests[level]); |
92 | else |
93 | s += sprintf(s, "%s ", pm_tests[level]); |
94 | } |
95 | |
96 | if (s != buf) |
97 | /* convert the last space to a newline */ |
98 | *(s-1) = '\n'; |
99 | |
100 | return (s - buf); |
101 | } |
102 | |
103 | static ssize_t pm_test_store(struct kobject *kobj, struct kobj_attribute *attr, |
104 | const char *buf, size_t n) |
105 | { |
106 | const char * const *s; |
107 | int level; |
108 | char *p; |
109 | int len; |
110 | int error = -EINVAL; |
111 | |
112 | p = memchr(buf, '\n', n); |
113 | len = p ? p - buf : n; |
114 | |
115 | mutex_lock(&pm_mutex); |
116 | |
117 | level = TEST_FIRST; |
118 | for (s = &pm_tests[level]; level <= TEST_MAX; s++, level++) |
119 | if (*s && len == strlen(*s) && !strncmp(buf, *s, len)) { |
120 | pm_test_level = level; |
121 | error = 0; |
122 | break; |
123 | } |
124 | |
125 | mutex_unlock(&pm_mutex); |
126 | |
127 | return error ? error : n; |
128 | } |
129 | |
130 | power_attr(pm_test); |
131 | #endif /* CONFIG_PM_DEBUG */ |
132 | |
133 | #endif /* CONFIG_PM_SLEEP */ |
134 | |
135 | struct kobject *power_kobj; |
136 | |
137 | /** |
138 | * state - control system power state. |
139 | * |
140 | * show() returns what states are supported, which is hard-coded to |
141 | * 'standby' (Power-On Suspend), 'mem' (Suspend-to-RAM), and |
142 | * 'disk' (Suspend-to-Disk). |
143 | * |
144 | * store() accepts one of those strings, translates it into the |
145 | * proper enumerated value, and initiates a suspend transition. |
146 | */ |
147 | static ssize_t state_show(struct kobject *kobj, struct kobj_attribute *attr, |
148 | char *buf) |
149 | { |
150 | char *s = buf; |
151 | #ifdef CONFIG_SUSPEND |
152 | int i; |
153 | |
154 | for (i = 0; i < PM_SUSPEND_MAX; i++) { |
155 | if (pm_states[i] && valid_state(i)) |
156 | s += sprintf(s,"%s ", pm_states[i]); |
157 | } |
158 | #endif |
159 | #ifdef CONFIG_HIBERNATION |
160 | s += sprintf(s, "%s\n", "disk"); |
161 | #else |
162 | if (s != buf) |
163 | /* convert the last space to a newline */ |
164 | *(s-1) = '\n'; |
165 | #endif |
166 | return (s - buf); |
167 | } |
168 | |
169 | static ssize_t state_store(struct kobject *kobj, struct kobj_attribute *attr, |
170 | const char *buf, size_t n) |
171 | { |
172 | #ifdef CONFIG_SUSPEND |
173 | suspend_state_t state = PM_SUSPEND_STANDBY; |
174 | const char * const *s; |
175 | #endif |
176 | char *p; |
177 | int len; |
178 | int error = -EINVAL; |
179 | |
180 | p = memchr(buf, '\n', n); |
181 | len = p ? p - buf : n; |
182 | |
183 | /* First, check if we are requested to hibernate */ |
184 | if (len == 4 && !strncmp(buf, "disk", len)) { |
185 | error = hibernate(); |
186 | goto Exit; |
187 | } |
188 | |
189 | #ifdef CONFIG_SUSPEND |
190 | for (s = &pm_states[state]; state < PM_SUSPEND_MAX; s++, state++) { |
191 | if (*s && len == strlen(*s) && !strncmp(buf, *s, len)) |
192 | break; |
193 | } |
194 | if (state < PM_SUSPEND_MAX && *s) |
195 | error = enter_state(state); |
196 | #endif |
197 | |
198 | Exit: |
199 | return error ? error : n; |
200 | } |
201 | |
202 | power_attr(state); |
203 | |
204 | #ifdef CONFIG_PM_SLEEP |
205 | /* |
206 | * The 'wakeup_count' attribute, along with the functions defined in |
207 | * drivers/base/power/wakeup.c, provides a means by which wakeup events can be |
208 | * handled in a non-racy way. |
209 | * |
210 | * If a wakeup event occurs when the system is in a sleep state, it simply is |
211 | * woken up. In turn, if an event that would wake the system up from a sleep |
212 | * state occurs when it is undergoing a transition to that sleep state, the |
213 | * transition should be aborted. Moreover, if such an event occurs when the |
214 | * system is in the working state, an attempt to start a transition to the |
215 | * given sleep state should fail during certain period after the detection of |
216 | * the event. Using the 'state' attribute alone is not sufficient to satisfy |
217 | * these requirements, because a wakeup event may occur exactly when 'state' |
218 | * is being written to and may be delivered to user space right before it is |
219 | * frozen, so the event will remain only partially processed until the system is |
220 | * woken up by another event. In particular, it won't cause the transition to |
221 | * a sleep state to be aborted. |
222 | * |
223 | * This difficulty may be overcome if user space uses 'wakeup_count' before |
224 | * writing to 'state'. It first should read from 'wakeup_count' and store |
225 | * the read value. Then, after carrying out its own preparations for the system |
226 | * transition to a sleep state, it should write the stored value to |
227 | * 'wakeup_count'. If that fails, at least one wakeup event has occurred since |
228 | * 'wakeup_count' was read and 'state' should not be written to. Otherwise, it |
229 | * is allowed to write to 'state', but the transition will be aborted if there |
230 | * are any wakeup events detected after 'wakeup_count' was written to. |
231 | */ |
232 | |
233 | static ssize_t wakeup_count_show(struct kobject *kobj, |
234 | struct kobj_attribute *attr, |
235 | char *buf) |
236 | { |
237 | unsigned int val; |
238 | |
239 | return pm_get_wakeup_count(&val) ? sprintf(buf, "%u\n", val) : -EINTR; |
240 | } |
241 | |
242 | static ssize_t wakeup_count_store(struct kobject *kobj, |
243 | struct kobj_attribute *attr, |
244 | const char *buf, size_t n) |
245 | { |
246 | unsigned int val; |
247 | |
248 | if (sscanf(buf, "%u", &val) == 1) { |
249 | if (pm_save_wakeup_count(val)) |
250 | return n; |
251 | } |
252 | return -EINVAL; |
253 | } |
254 | |
255 | power_attr(wakeup_count); |
256 | #endif /* CONFIG_PM_SLEEP */ |
257 | |
258 | #ifdef CONFIG_PM_TRACE |
259 | int pm_trace_enabled; |
260 | |
261 | static ssize_t pm_trace_show(struct kobject *kobj, struct kobj_attribute *attr, |
262 | char *buf) |
263 | { |
264 | return sprintf(buf, "%d\n", pm_trace_enabled); |
265 | } |
266 | |
267 | static ssize_t |
268 | pm_trace_store(struct kobject *kobj, struct kobj_attribute *attr, |
269 | const char *buf, size_t n) |
270 | { |
271 | int val; |
272 | |
273 | if (sscanf(buf, "%d", &val) == 1) { |
274 | pm_trace_enabled = !!val; |
275 | return n; |
276 | } |
277 | return -EINVAL; |
278 | } |
279 | |
280 | power_attr(pm_trace); |
281 | |
282 | static ssize_t pm_trace_dev_match_show(struct kobject *kobj, |
283 | struct kobj_attribute *attr, |
284 | char *buf) |
285 | { |
286 | return show_trace_dev_match(buf, PAGE_SIZE); |
287 | } |
288 | |
289 | static ssize_t |
290 | pm_trace_dev_match_store(struct kobject *kobj, struct kobj_attribute *attr, |
291 | const char *buf, size_t n) |
292 | { |
293 | return -EINVAL; |
294 | } |
295 | |
296 | power_attr(pm_trace_dev_match); |
297 | |
298 | #endif /* CONFIG_PM_TRACE */ |
299 | |
300 | static struct attribute * g[] = { |
301 | &state_attr.attr, |
302 | #ifdef CONFIG_PM_TRACE |
303 | &pm_trace_attr.attr, |
304 | &pm_trace_dev_match_attr.attr, |
305 | #endif |
306 | #ifdef CONFIG_PM_SLEEP |
307 | &pm_async_attr.attr, |
308 | &wakeup_count_attr.attr, |
309 | #ifdef CONFIG_PM_DEBUG |
310 | &pm_test_attr.attr, |
311 | #endif |
312 | #endif |
313 | NULL, |
314 | }; |
315 | |
316 | static struct attribute_group attr_group = { |
317 | .attrs = g, |
318 | }; |
319 | |
320 | #ifdef CONFIG_PM_RUNTIME |
321 | struct workqueue_struct *pm_wq; |
322 | EXPORT_SYMBOL_GPL(pm_wq); |
323 | |
324 | static int __init pm_start_workqueue(void) |
325 | { |
326 | pm_wq = alloc_workqueue("pm", WQ_FREEZABLE, 0); |
327 | |
328 | return pm_wq ? 0 : -ENOMEM; |
329 | } |
330 | #else |
331 | static inline int pm_start_workqueue(void) { return 0; } |
332 | #endif |
333 | |
334 | static int __init pm_init(void) |
335 | { |
336 | int error = pm_start_workqueue(); |
337 | if (error) |
338 | return error; |
339 | hibernate_image_size_init(); |
340 | hibernate_reserved_size_init(); |
341 | power_kobj = kobject_create_and_add("power", NULL); |
342 | if (!power_kobj) |
343 | return -ENOMEM; |
344 | return sysfs_create_group(power_kobj, &attr_group); |
345 | } |
346 | |
347 | core_initcall(pm_init); |
348 |
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