snapshot: Use pm_mutex for mutual exclusion
[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/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 #include <linux/syscalls.h>
24
25 #include "power.h"
26
27 DEFINE_MUTEX(pm_mutex);
28
29 unsigned int pm_flags;
30 EXPORT_SYMBOL(pm_flags);
31
32 #ifdef CONFIG_PM_SLEEP
33
34 /* Routines for PM-transition notifications */
35
36 static BLOCKING_NOTIFIER_HEAD(pm_chain_head);
37
38 int register_pm_notifier(struct notifier_block *nb)
39 {
40         return blocking_notifier_chain_register(&pm_chain_head, nb);
41 }
42 EXPORT_SYMBOL_GPL(register_pm_notifier);
43
44 int unregister_pm_notifier(struct notifier_block *nb)
45 {
46         return blocking_notifier_chain_unregister(&pm_chain_head, nb);
47 }
48 EXPORT_SYMBOL_GPL(unregister_pm_notifier);
49
50 int pm_notifier_call_chain(unsigned long val)
51 {
52         return (blocking_notifier_call_chain(&pm_chain_head, val, NULL)
53                         == NOTIFY_BAD) ? -EINVAL : 0;
54 }
55
56 #ifdef CONFIG_PM_DEBUG
57 int pm_test_level = TEST_NONE;
58
59 static int suspend_test(int level)
60 {
61         if (pm_test_level == level) {
62                 printk(KERN_INFO "suspend debug: Waiting for 5 seconds.\n");
63                 mdelay(5000);
64                 return 1;
65         }
66         return 0;
67 }
68
69 static const char * const pm_tests[__TEST_AFTER_LAST] = {
70         [TEST_NONE] = "none",
71         [TEST_CORE] = "core",
72         [TEST_CPUS] = "processors",
73         [TEST_PLATFORM] = "platform",
74         [TEST_DEVICES] = "devices",
75         [TEST_FREEZER] = "freezer",
76 };
77
78 static ssize_t pm_test_show(struct kobject *kobj, struct kobj_attribute *attr,
79                                 char *buf)
80 {
81         char *s = buf;
82         int level;
83
84         for (level = TEST_FIRST; level <= TEST_MAX; level++)
85                 if (pm_tests[level]) {
86                         if (level == pm_test_level)
87                                 s += sprintf(s, "[%s] ", pm_tests[level]);
88                         else
89                                 s += sprintf(s, "%s ", pm_tests[level]);
90                 }
91
92         if (s != buf)
93                 /* convert the last space to a newline */
94                 *(s-1) = '\n';
95
96         return (s - buf);
97 }
98
99 static ssize_t pm_test_store(struct kobject *kobj, struct kobj_attribute *attr,
100                                 const char *buf, size_t n)
101 {
102         const char * const *s;
103         int level;
104         char *p;
105         int len;
106         int error = -EINVAL;
107
108         p = memchr(buf, '\n', n);
109         len = p ? p - buf : n;
110
111         mutex_lock(&pm_mutex);
112
113         level = TEST_FIRST;
114         for (s = &pm_tests[level]; level <= TEST_MAX; s++, level++)
115                 if (*s && len == strlen(*s) && !strncmp(buf, *s, len)) {
116                         pm_test_level = level;
117                         error = 0;
118                         break;
119                 }
120
121         mutex_unlock(&pm_mutex);
122
123         return error ? error : n;
124 }
125
126 power_attr(pm_test);
127 #else /* !CONFIG_PM_DEBUG */
128 static inline int suspend_test(int level) { return 0; }
129 #endif /* !CONFIG_PM_DEBUG */
130
131 #endif /* CONFIG_PM_SLEEP */
132
133 #ifdef CONFIG_SUSPEND
134
135 /* This is just an arbitrary number */
136 #define FREE_PAGE_NUMBER (100)
137
138 static struct platform_suspend_ops *suspend_ops;
139
140 /**
141  *      suspend_set_ops - Set the global suspend method table.
142  *      @ops:   Pointer to ops structure.
143  */
144
145 void suspend_set_ops(struct platform_suspend_ops *ops)
146 {
147         mutex_lock(&pm_mutex);
148         suspend_ops = ops;
149         mutex_unlock(&pm_mutex);
150 }
151
152 /**
153  * suspend_valid_only_mem - generic memory-only valid callback
154  *
155  * Platform drivers that implement mem suspend only and only need
156  * to check for that in their .valid callback can use this instead
157  * of rolling their own .valid callback.
158  */
159 int suspend_valid_only_mem(suspend_state_t state)
160 {
161         return state == PM_SUSPEND_MEM;
162 }
163
164 /**
165  *      suspend_prepare - Do prep work before entering low-power state.
166  *
167  *      This is common code that is called for each state that we're entering.
168  *      Run suspend notifiers, allocate a console and stop all processes.
169  */
170 static int suspend_prepare(void)
171 {
172         int error;
173         unsigned int free_pages;
174
175         if (!suspend_ops || !suspend_ops->enter)
176                 return -EPERM;
177
178         pm_prepare_console();
179
180         error = pm_notifier_call_chain(PM_SUSPEND_PREPARE);
181         if (error)
182                 goto Finish;
183
184         if (suspend_freeze_processes()) {
185                 error = -EAGAIN;
186                 goto Thaw;
187         }
188
189         free_pages = global_page_state(NR_FREE_PAGES);
190         if (free_pages < FREE_PAGE_NUMBER) {
191                 pr_debug("PM: free some memory\n");
192                 shrink_all_memory(FREE_PAGE_NUMBER - free_pages);
193                 if (nr_free_pages() < FREE_PAGE_NUMBER) {
194                         error = -ENOMEM;
195                         printk(KERN_ERR "PM: No enough memory\n");
196                 }
197         }
198         if (!error)
199                 return 0;
200
201  Thaw:
202         suspend_thaw_processes();
203  Finish:
204         pm_notifier_call_chain(PM_POST_SUSPEND);
205         pm_restore_console();
206         return error;
207 }
208
209 /* default implementation */
210 void __attribute__ ((weak)) arch_suspend_disable_irqs(void)
211 {
212         local_irq_disable();
213 }
214
215 /* default implementation */
216 void __attribute__ ((weak)) arch_suspend_enable_irqs(void)
217 {
218         local_irq_enable();
219 }
220
221 /**
222  *      suspend_enter - enter the desired system sleep state.
223  *      @state:         state to enter
224  *
225  *      This function should be called after devices have been suspended.
226  */
227 static int suspend_enter(suspend_state_t state)
228 {
229         int error = 0;
230
231         arch_suspend_disable_irqs();
232         BUG_ON(!irqs_disabled());
233
234         if ((error = device_power_down(PMSG_SUSPEND))) {
235                 printk(KERN_ERR "PM: Some devices failed to power down\n");
236                 goto Done;
237         }
238
239         if (!suspend_test(TEST_CORE))
240                 error = suspend_ops->enter(state);
241
242         device_power_up();
243  Done:
244         arch_suspend_enable_irqs();
245         BUG_ON(irqs_disabled());
246         return error;
247 }
248
249 /**
250  *      suspend_devices_and_enter - suspend devices and enter the desired system
251  *                                  sleep state.
252  *      @state:           state to enter
253  */
254 int suspend_devices_and_enter(suspend_state_t state)
255 {
256         int error;
257
258         if (!suspend_ops)
259                 return -ENOSYS;
260
261         if (suspend_ops->begin) {
262                 error = suspend_ops->begin(state);
263                 if (error)
264                         goto Close;
265         }
266         suspend_console();
267         error = device_suspend(PMSG_SUSPEND);
268         if (error) {
269                 printk(KERN_ERR "PM: Some devices failed to suspend\n");
270                 goto Resume_console;
271         }
272
273         if (suspend_test(TEST_DEVICES))
274                 goto Resume_devices;
275
276         if (suspend_ops->prepare) {
277                 error = suspend_ops->prepare();
278                 if (error)
279                         goto Resume_devices;
280         }
281
282         if (suspend_test(TEST_PLATFORM))
283                 goto Finish;
284
285         error = disable_nonboot_cpus();
286         if (!error && !suspend_test(TEST_CPUS))
287                 suspend_enter(state);
288
289         enable_nonboot_cpus();
290  Finish:
291         if (suspend_ops->finish)
292                 suspend_ops->finish();
293  Resume_devices:
294         device_resume();
295  Resume_console:
296         resume_console();
297  Close:
298         if (suspend_ops->end)
299                 suspend_ops->end();
300         return error;
301 }
302
303 /**
304  *      suspend_finish - Do final work before exiting suspend sequence.
305  *
306  *      Call platform code to clean up, restart processes, and free the 
307  *      console that we've allocated. This is not called for suspend-to-disk.
308  */
309 static void suspend_finish(void)
310 {
311         suspend_thaw_processes();
312         pm_notifier_call_chain(PM_POST_SUSPEND);
313         pm_restore_console();
314 }
315
316
317
318
319 static const char * const pm_states[PM_SUSPEND_MAX] = {
320         [PM_SUSPEND_STANDBY]    = "standby",
321         [PM_SUSPEND_MEM]        = "mem",
322 };
323
324 static inline int valid_state(suspend_state_t state)
325 {
326         /* All states need lowlevel support and need to be valid
327          * to the lowlevel implementation, no valid callback
328          * implies that none are valid. */
329         if (!suspend_ops || !suspend_ops->valid || !suspend_ops->valid(state))
330                 return 0;
331         return 1;
332 }
333
334
335 /**
336  *      enter_state - Do common work of entering low-power state.
337  *      @state:         pm_state structure for state we're entering.
338  *
339  *      Make sure we're the only ones trying to enter a sleep state. Fail
340  *      if someone has beat us to it, since we don't want anything weird to
341  *      happen when we wake up.
342  *      Then, do the setup for suspend, enter the state, and cleaup (after
343  *      we've woken up).
344  */
345 static int enter_state(suspend_state_t state)
346 {
347         int error;
348
349         if (!valid_state(state))
350                 return -ENODEV;
351
352         if (!mutex_trylock(&pm_mutex))
353                 return -EBUSY;
354
355         printk(KERN_INFO "PM: Syncing filesystems ... ");
356         sys_sync();
357         printk("done.\n");
358
359         pr_debug("PM: Preparing system for %s sleep\n", pm_states[state]);
360         error = suspend_prepare();
361         if (error)
362                 goto Unlock;
363
364         if (suspend_test(TEST_FREEZER))
365                 goto Finish;
366
367         pr_debug("PM: Entering %s sleep\n", pm_states[state]);
368         error = suspend_devices_and_enter(state);
369
370  Finish:
371         pr_debug("PM: Finishing wakeup.\n");
372         suspend_finish();
373  Unlock:
374         mutex_unlock(&pm_mutex);
375         return error;
376 }
377
378
379 /**
380  *      pm_suspend - Externally visible function for suspending system.
381  *      @state:         Enumerated value of state to enter.
382  *
383  *      Determine whether or not value is within range, get state 
384  *      structure, and enter (above).
385  */
386
387 int pm_suspend(suspend_state_t state)
388 {
389         if (state > PM_SUSPEND_ON && state <= PM_SUSPEND_MAX)
390                 return enter_state(state);
391         return -EINVAL;
392 }
393
394 EXPORT_SYMBOL(pm_suspend);
395
396 #endif /* CONFIG_SUSPEND */
397
398 struct kobject *power_kobj;
399
400 /**
401  *      state - control system power state.
402  *
403  *      show() returns what states are supported, which is hard-coded to
404  *      'standby' (Power-On Suspend), 'mem' (Suspend-to-RAM), and
405  *      'disk' (Suspend-to-Disk).
406  *
407  *      store() accepts one of those strings, translates it into the 
408  *      proper enumerated value, and initiates a suspend transition.
409  */
410
411 static ssize_t state_show(struct kobject *kobj, struct kobj_attribute *attr,
412                           char *buf)
413 {
414         char *s = buf;
415 #ifdef CONFIG_SUSPEND
416         int i;
417
418         for (i = 0; i < PM_SUSPEND_MAX; i++) {
419                 if (pm_states[i] && valid_state(i))
420                         s += sprintf(s,"%s ", pm_states[i]);
421         }
422 #endif
423 #ifdef CONFIG_HIBERNATION
424         s += sprintf(s, "%s\n", "disk");
425 #else
426         if (s != buf)
427                 /* convert the last space to a newline */
428                 *(s-1) = '\n';
429 #endif
430         return (s - buf);
431 }
432
433 static ssize_t state_store(struct kobject *kobj, struct kobj_attribute *attr,
434                            const char *buf, size_t n)
435 {
436 #ifdef CONFIG_SUSPEND
437         suspend_state_t state = PM_SUSPEND_STANDBY;
438         const char * const *s;
439 #endif
440         char *p;
441         int len;
442         int error = -EINVAL;
443
444         p = memchr(buf, '\n', n);
445         len = p ? p - buf : n;
446
447         /* First, check if we are requested to hibernate */
448         if (len == 4 && !strncmp(buf, "disk", len)) {
449                 error = hibernate();
450   goto Exit;
451         }
452
453 #ifdef CONFIG_SUSPEND
454         for (s = &pm_states[state]; state < PM_SUSPEND_MAX; s++, state++) {
455                 if (*s && len == strlen(*s) && !strncmp(buf, *s, len))
456                         break;
457         }
458         if (state < PM_SUSPEND_MAX && *s)
459                 error = enter_state(state);
460 #endif
461
462  Exit:
463         return error ? error : n;
464 }
465
466 power_attr(state);
467
468 #ifdef CONFIG_PM_TRACE
469 int pm_trace_enabled;
470
471 static ssize_t pm_trace_show(struct kobject *kobj, struct kobj_attribute *attr,
472                              char *buf)
473 {
474         return sprintf(buf, "%d\n", pm_trace_enabled);
475 }
476
477 static ssize_t
478 pm_trace_store(struct kobject *kobj, struct kobj_attribute *attr,
479                const char *buf, size_t n)
480 {
481         int val;
482
483         if (sscanf(buf, "%d", &val) == 1) {
484                 pm_trace_enabled = !!val;
485                 return n;
486         }
487         return -EINVAL;
488 }
489
490 power_attr(pm_trace);
491 #endif /* CONFIG_PM_TRACE */
492
493 static struct attribute * g[] = {
494         &state_attr.attr,
495 #ifdef CONFIG_PM_TRACE
496         &pm_trace_attr.attr,
497 #endif
498 #if defined(CONFIG_PM_SLEEP) && defined(CONFIG_PM_DEBUG)
499         &pm_test_attr.attr,
500 #endif
501         NULL,
502 };
503
504 static struct attribute_group attr_group = {
505         .attrs = g,
506 };
507
508
509 static int __init pm_init(void)
510 {
511         power_kobj = kobject_create_and_add("power", NULL);
512         if (!power_kobj)
513                 return -ENOMEM;
514         return sysfs_create_group(power_kobj, &attr_group);
515 }
516
517 core_initcall(pm_init);