Revert "PM: Add user-space wake lock api."
[linux-2.6.git] / kernel / power / main.c
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/export.h>
12 #include <linux/kobject.h>
13 #include <linux/string.h>
14 #include <linux/resume-trace.h>
15 #include <linux/workqueue.h>
16 #include <linux/debugfs.h>
17 #include <linux/seq_file.h>
18
19 #include "power.h"
20
21 DEFINE_MUTEX(pm_mutex);
22
23 #ifdef CONFIG_PM_SLEEP
24
25 /* Routines for PM-transition notifications */
26
27 static BLOCKING_NOTIFIER_HEAD(pm_chain_head);
28
29 int register_pm_notifier(struct notifier_block *nb)
30 {
31         return blocking_notifier_chain_register(&pm_chain_head, nb);
32 }
33 EXPORT_SYMBOL_GPL(register_pm_notifier);
34
35 int unregister_pm_notifier(struct notifier_block *nb)
36 {
37         return blocking_notifier_chain_unregister(&pm_chain_head, nb);
38 }
39 EXPORT_SYMBOL_GPL(unregister_pm_notifier);
40
41 int pm_notifier_call_chain(unsigned long val)
42 {
43         int ret = blocking_notifier_call_chain(&pm_chain_head, val, NULL);
44
45         return notifier_to_errno(ret);
46 }
47
48 /* If set, devices may be suspended and resumed asynchronously. */
49 int pm_async_enabled = 1;
50
51 static ssize_t pm_async_show(struct kobject *kobj, struct kobj_attribute *attr,
52                              char *buf)
53 {
54         return sprintf(buf, "%d\n", pm_async_enabled);
55 }
56
57 static ssize_t pm_async_store(struct kobject *kobj, struct kobj_attribute *attr,
58                               const char *buf, size_t n)
59 {
60         unsigned long val;
61
62         if (strict_strtoul(buf, 10, &val))
63                 return -EINVAL;
64
65         if (val > 1)
66                 return -EINVAL;
67
68         pm_async_enabled = val;
69         return n;
70 }
71
72 power_attr(pm_async);
73
74 #ifdef CONFIG_PM_DEBUG
75 int pm_test_level = TEST_NONE;
76
77 static const char * const pm_tests[__TEST_AFTER_LAST] = {
78         [TEST_NONE] = "none",
79         [TEST_CORE] = "core",
80         [TEST_CPUS] = "processors",
81         [TEST_PLATFORM] = "platform",
82         [TEST_DEVICES] = "devices",
83         [TEST_FREEZER] = "freezer",
84 };
85
86 static ssize_t pm_test_show(struct kobject *kobj, struct kobj_attribute *attr,
87                                 char *buf)
88 {
89         char *s = buf;
90         int level;
91
92         for (level = TEST_FIRST; level <= TEST_MAX; level++)
93                 if (pm_tests[level]) {
94                         if (level == pm_test_level)
95                                 s += sprintf(s, "[%s] ", pm_tests[level]);
96                         else
97                                 s += sprintf(s, "%s ", pm_tests[level]);
98                 }
99
100         if (s != buf)
101                 /* convert the last space to a newline */
102                 *(s-1) = '\n';
103
104         return (s - buf);
105 }
106
107 static ssize_t pm_test_store(struct kobject *kobj, struct kobj_attribute *attr,
108                                 const char *buf, size_t n)
109 {
110         const char * const *s;
111         int level;
112         char *p;
113         int len;
114         int error = -EINVAL;
115
116         p = memchr(buf, '\n', n);
117         len = p ? p - buf : n;
118
119         lock_system_sleep();
120
121         level = TEST_FIRST;
122         for (s = &pm_tests[level]; level <= TEST_MAX; s++, level++)
123                 if (*s && len == strlen(*s) && !strncmp(buf, *s, len)) {
124                         pm_test_level = level;
125                         error = 0;
126                         break;
127                 }
128
129         unlock_system_sleep();
130
131         return error ? error : n;
132 }
133
134 power_attr(pm_test);
135 #endif /* CONFIG_PM_DEBUG */
136
137 #ifdef CONFIG_DEBUG_FS
138 static char *suspend_step_name(enum suspend_stat_step step)
139 {
140         switch (step) {
141         case SUSPEND_FREEZE:
142                 return "freeze";
143         case SUSPEND_PREPARE:
144                 return "prepare";
145         case SUSPEND_SUSPEND:
146                 return "suspend";
147         case SUSPEND_SUSPEND_NOIRQ:
148                 return "suspend_noirq";
149         case SUSPEND_RESUME_NOIRQ:
150                 return "resume_noirq";
151         case SUSPEND_RESUME:
152                 return "resume";
153         default:
154                 return "";
155         }
156 }
157
158 static int suspend_stats_show(struct seq_file *s, void *unused)
159 {
160         int i, index, last_dev, last_errno, last_step;
161
162         last_dev = suspend_stats.last_failed_dev + REC_FAILED_NUM - 1;
163         last_dev %= REC_FAILED_NUM;
164         last_errno = suspend_stats.last_failed_errno + REC_FAILED_NUM - 1;
165         last_errno %= REC_FAILED_NUM;
166         last_step = suspend_stats.last_failed_step + REC_FAILED_NUM - 1;
167         last_step %= REC_FAILED_NUM;
168         seq_printf(s, "%s: %d\n%s: %d\n%s: %d\n%s: %d\n"
169                         "%s: %d\n%s: %d\n%s: %d\n%s: %d\n",
170                         "success", suspend_stats.success,
171                         "fail", suspend_stats.fail,
172                         "failed_freeze", suspend_stats.failed_freeze,
173                         "failed_prepare", suspend_stats.failed_prepare,
174                         "failed_suspend", suspend_stats.failed_suspend,
175                         "failed_suspend_noirq",
176                                 suspend_stats.failed_suspend_noirq,
177                         "failed_resume", suspend_stats.failed_resume,
178                         "failed_resume_noirq",
179                                 suspend_stats.failed_resume_noirq);
180         seq_printf(s,   "failures:\n  last_failed_dev:\t%-s\n",
181                         suspend_stats.failed_devs[last_dev]);
182         for (i = 1; i < REC_FAILED_NUM; i++) {
183                 index = last_dev + REC_FAILED_NUM - i;
184                 index %= REC_FAILED_NUM;
185                 seq_printf(s, "\t\t\t%-s\n",
186                         suspend_stats.failed_devs[index]);
187         }
188         seq_printf(s,   "  last_failed_errno:\t%-d\n",
189                         suspend_stats.errno[last_errno]);
190         for (i = 1; i < REC_FAILED_NUM; i++) {
191                 index = last_errno + REC_FAILED_NUM - i;
192                 index %= REC_FAILED_NUM;
193                 seq_printf(s, "\t\t\t%-d\n",
194                         suspend_stats.errno[index]);
195         }
196         seq_printf(s,   "  last_failed_step:\t%-s\n",
197                         suspend_step_name(
198                                 suspend_stats.failed_steps[last_step]));
199         for (i = 1; i < REC_FAILED_NUM; i++) {
200                 index = last_step + REC_FAILED_NUM - i;
201                 index %= REC_FAILED_NUM;
202                 seq_printf(s, "\t\t\t%-s\n",
203                         suspend_step_name(
204                                 suspend_stats.failed_steps[index]));
205         }
206
207         return 0;
208 }
209
210 static int suspend_stats_open(struct inode *inode, struct file *file)
211 {
212         return single_open(file, suspend_stats_show, NULL);
213 }
214
215 static const struct file_operations suspend_stats_operations = {
216         .open           = suspend_stats_open,
217         .read           = seq_read,
218         .llseek         = seq_lseek,
219         .release        = single_release,
220 };
221
222 static int __init pm_debugfs_init(void)
223 {
224         debugfs_create_file("suspend_stats", S_IFREG | S_IRUGO,
225                         NULL, NULL, &suspend_stats_operations);
226         return 0;
227 }
228
229 late_initcall(pm_debugfs_init);
230 #endif /* CONFIG_DEBUG_FS */
231
232 #endif /* CONFIG_PM_SLEEP */
233
234 struct kobject *power_kobj;
235
236 /**
237  *      state - control system power state.
238  *
239  *      show() returns what states are supported, which is hard-coded to
240  *      'standby' (Power-On Suspend), 'mem' (Suspend-to-RAM), and
241  *      'disk' (Suspend-to-Disk).
242  *
243  *      store() accepts one of those strings, translates it into the
244  *      proper enumerated value, and initiates a suspend transition.
245  */
246 static ssize_t state_show(struct kobject *kobj, struct kobj_attribute *attr,
247                           char *buf)
248 {
249         char *s = buf;
250 #ifdef CONFIG_SUSPEND
251         int i;
252
253         for (i = 0; i < PM_SUSPEND_MAX; i++) {
254                 if (pm_states[i] && valid_state(i))
255                         s += sprintf(s,"%s ", pm_states[i]);
256         }
257 #endif
258 #ifdef CONFIG_HIBERNATION
259         s += sprintf(s, "%s\n", "disk");
260 #else
261         if (s != buf)
262                 /* convert the last space to a newline */
263                 *(s-1) = '\n';
264 #endif
265         return (s - buf);
266 }
267
268 static ssize_t state_store(struct kobject *kobj, struct kobj_attribute *attr,
269                            const char *buf, size_t n)
270 {
271 #ifdef CONFIG_SUSPEND
272         suspend_state_t state = PM_SUSPEND_STANDBY;
273         const char * const *s;
274 #endif
275         char *p;
276         int len;
277         int error = -EINVAL;
278
279         p = memchr(buf, '\n', n);
280         len = p ? p - buf : n;
281
282         /* First, check if we are requested to hibernate */
283         if (len == 4 && !strncmp(buf, "disk", len)) {
284                 error = hibernate();
285                 goto Exit;
286         }
287
288 #ifdef CONFIG_SUSPEND
289         for (s = &pm_states[state]; state < PM_SUSPEND_MAX; s++, state++) {
290                 if (*s && len == strlen(*s) && !strncmp(buf, *s, len))
291                         break;
292         }
293         if (state < PM_SUSPEND_MAX && *s) {
294                 error = enter_state(state);
295                 if (error) {
296                         suspend_stats.fail++;
297                         dpm_save_failed_errno(error);
298                 } else
299                         suspend_stats.success++;
300         }
301 #endif
302
303  Exit:
304         return error ? error : n;
305 }
306
307 power_attr(state);
308
309 #ifdef CONFIG_PM_SLEEP
310 /*
311  * The 'wakeup_count' attribute, along with the functions defined in
312  * drivers/base/power/wakeup.c, provides a means by which wakeup events can be
313  * handled in a non-racy way.
314  *
315  * If a wakeup event occurs when the system is in a sleep state, it simply is
316  * woken up.  In turn, if an event that would wake the system up from a sleep
317  * state occurs when it is undergoing a transition to that sleep state, the
318  * transition should be aborted.  Moreover, if such an event occurs when the
319  * system is in the working state, an attempt to start a transition to the
320  * given sleep state should fail during certain period after the detection of
321  * the event.  Using the 'state' attribute alone is not sufficient to satisfy
322  * these requirements, because a wakeup event may occur exactly when 'state'
323  * is being written to and may be delivered to user space right before it is
324  * frozen, so the event will remain only partially processed until the system is
325  * woken up by another event.  In particular, it won't cause the transition to
326  * a sleep state to be aborted.
327  *
328  * This difficulty may be overcome if user space uses 'wakeup_count' before
329  * writing to 'state'.  It first should read from 'wakeup_count' and store
330  * the read value.  Then, after carrying out its own preparations for the system
331  * transition to a sleep state, it should write the stored value to
332  * 'wakeup_count'.  If that fails, at least one wakeup event has occurred since
333  * 'wakeup_count' was read and 'state' should not be written to.  Otherwise, it
334  * is allowed to write to 'state', but the transition will be aborted if there
335  * are any wakeup events detected after 'wakeup_count' was written to.
336  */
337
338 static ssize_t wakeup_count_show(struct kobject *kobj,
339                                 struct kobj_attribute *attr,
340                                 char *buf)
341 {
342         unsigned int val;
343
344         return pm_get_wakeup_count(&val) ? sprintf(buf, "%u\n", val) : -EINTR;
345 }
346
347 static ssize_t wakeup_count_store(struct kobject *kobj,
348                                 struct kobj_attribute *attr,
349                                 const char *buf, size_t n)
350 {
351         unsigned int val;
352
353         if (sscanf(buf, "%u", &val) == 1) {
354                 if (pm_save_wakeup_count(val))
355                         return n;
356         }
357         return -EINVAL;
358 }
359
360 power_attr(wakeup_count);
361 #endif /* CONFIG_PM_SLEEP */
362
363 #ifdef CONFIG_PM_TRACE
364 int pm_trace_enabled;
365
366 static ssize_t pm_trace_show(struct kobject *kobj, struct kobj_attribute *attr,
367                              char *buf)
368 {
369         return sprintf(buf, "%d\n", pm_trace_enabled);
370 }
371
372 static ssize_t
373 pm_trace_store(struct kobject *kobj, struct kobj_attribute *attr,
374                const char *buf, size_t n)
375 {
376         int val;
377
378         if (sscanf(buf, "%d", &val) == 1) {
379                 pm_trace_enabled = !!val;
380                 return n;
381         }
382         return -EINVAL;
383 }
384
385 power_attr(pm_trace);
386
387 static ssize_t pm_trace_dev_match_show(struct kobject *kobj,
388                                        struct kobj_attribute *attr,
389                                        char *buf)
390 {
391         return show_trace_dev_match(buf, PAGE_SIZE);
392 }
393
394 static ssize_t
395 pm_trace_dev_match_store(struct kobject *kobj, struct kobj_attribute *attr,
396                          const char *buf, size_t n)
397 {
398         return -EINVAL;
399 }
400
401 power_attr(pm_trace_dev_match);
402
403 #endif /* CONFIG_PM_TRACE */
404
405 static struct attribute * g[] = {
406         &state_attr.attr,
407 #ifdef CONFIG_PM_TRACE
408         &pm_trace_attr.attr,
409         &pm_trace_dev_match_attr.attr,
410 #endif
411 #ifdef CONFIG_PM_SLEEP
412         &pm_async_attr.attr,
413         &wakeup_count_attr.attr,
414 #ifdef CONFIG_PM_DEBUG
415         &pm_test_attr.attr,
416 #endif
417 #endif
418         NULL,
419 };
420
421 static struct attribute_group attr_group = {
422         .attrs = g,
423 };
424
425 #ifdef CONFIG_PM_RUNTIME
426 struct workqueue_struct *pm_wq;
427 EXPORT_SYMBOL_GPL(pm_wq);
428
429 static int __init pm_start_workqueue(void)
430 {
431         pm_wq = alloc_workqueue("pm", WQ_FREEZABLE, 0);
432
433         return pm_wq ? 0 : -ENOMEM;
434 }
435 #else
436 static inline int pm_start_workqueue(void) { return 0; }
437 #endif
438
439 static int __init pm_init(void)
440 {
441         int error = pm_start_workqueue();
442         if (error)
443                 return error;
444         hibernate_image_size_init();
445         hibernate_reserved_size_init();
446         power_kobj = kobject_create_and_add("power", NULL);
447         if (!power_kobj)
448                 return -ENOMEM;
449         return sysfs_create_group(power_kobj, &attr_group);
450 }
451
452 core_initcall(pm_init);