Suspend: Fix comment in main.c
[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 #endif /* CONFIG_PM_SLEEP */
57
58 #ifdef CONFIG_SUSPEND
59
60 #ifdef CONFIG_PM_DEBUG
61 int pm_test_level = TEST_NONE;
62
63 static int suspend_test(int level)
64 {
65         if (pm_test_level == level) {
66                 printk(KERN_INFO "suspend debug: Waiting for 5 seconds.\n");
67                 mdelay(5000);
68                 return 1;
69         }
70         return 0;
71 }
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 #else /* !CONFIG_PM_DEBUG */
132 static inline int suspend_test(int level) { return 0; }
133 #endif /* !CONFIG_PM_DEBUG */
134
135
136 #ifdef CONFIG_SUSPEND
137
138 /* This is just an arbitrary number */
139 #define FREE_PAGE_NUMBER (100)
140
141 static struct platform_suspend_ops *suspend_ops;
142
143 /**
144  *      suspend_set_ops - Set the global suspend method table.
145  *      @ops:   Pointer to ops structure.
146  */
147
148 void suspend_set_ops(struct platform_suspend_ops *ops)
149 {
150         mutex_lock(&pm_mutex);
151         suspend_ops = ops;
152         mutex_unlock(&pm_mutex);
153 }
154
155 /**
156  * suspend_valid_only_mem - generic memory-only valid callback
157  *
158  * Platform drivers that implement mem suspend only and only need
159  * to check for that in their .valid callback can use this instead
160  * of rolling their own .valid callback.
161  */
162 int suspend_valid_only_mem(suspend_state_t state)
163 {
164         return state == PM_SUSPEND_MEM;
165 }
166
167 /**
168  *      suspend_prepare - Do prep work before entering low-power state.
169  *
170  *      This is common code that is called for each state that we're entering.
171  *      Run suspend notifiers, allocate a console and stop all processes.
172  */
173 static int suspend_prepare(void)
174 {
175         int error;
176         unsigned int free_pages;
177
178         if (!suspend_ops || !suspend_ops->enter)
179                 return -EPERM;
180
181         error = pm_notifier_call_chain(PM_SUSPEND_PREPARE);
182         if (error)
183                 goto Finish;
184
185         pm_prepare_console();
186
187         if (freeze_processes()) {
188                 error = -EAGAIN;
189                 goto Thaw;
190         }
191
192         free_pages = global_page_state(NR_FREE_PAGES);
193         if (free_pages < FREE_PAGE_NUMBER) {
194                 pr_debug("PM: free some memory\n");
195                 shrink_all_memory(FREE_PAGE_NUMBER - free_pages);
196                 if (nr_free_pages() < FREE_PAGE_NUMBER) {
197                         error = -ENOMEM;
198                         printk(KERN_ERR "PM: No enough memory\n");
199                 }
200         }
201         if (!error)
202                 return 0;
203
204  Thaw:
205         thaw_processes();
206         pm_restore_console();
207  Finish:
208         pm_notifier_call_chain(PM_POST_SUSPEND);
209         return error;
210 }
211
212 /* default implementation */
213 void __attribute__ ((weak)) arch_suspend_disable_irqs(void)
214 {
215         local_irq_disable();
216 }
217
218 /* default implementation */
219 void __attribute__ ((weak)) arch_suspend_enable_irqs(void)
220 {
221         local_irq_enable();
222 }
223
224 /**
225  *      suspend_enter - enter the desired system sleep state.
226  *      @state:         state to enter
227  *
228  *      This function should be called after devices have been suspended.
229  */
230 static int suspend_enter(suspend_state_t state)
231 {
232         int error = 0;
233
234         arch_suspend_disable_irqs();
235         BUG_ON(!irqs_disabled());
236
237         if ((error = device_power_down(PMSG_SUSPEND))) {
238                 printk(KERN_ERR "Some devices failed to power down\n");
239                 goto Done;
240         }
241
242         if (!suspend_test(TEST_CORE))
243                 error = suspend_ops->enter(state);
244
245         device_power_up();
246  Done:
247         arch_suspend_enable_irqs();
248         BUG_ON(irqs_disabled());
249         return error;
250 }
251
252 /**
253  *      suspend_devices_and_enter - suspend devices and enter the desired system
254  *                                  sleep state.
255  *      @state:           state to enter
256  */
257 int suspend_devices_and_enter(suspend_state_t state)
258 {
259         int error;
260
261         if (!suspend_ops)
262                 return -ENOSYS;
263
264         if (suspend_ops->set_target) {
265                 error = suspend_ops->set_target(state);
266                 if (error)
267                         return error;
268         }
269         suspend_console();
270         error = device_suspend(PMSG_SUSPEND);
271         if (error) {
272                 printk(KERN_ERR "Some devices failed to suspend\n");
273                 goto Resume_console;
274         }
275
276         if (suspend_test(TEST_DEVICES))
277                 goto Resume_devices;
278
279         if (suspend_ops->prepare) {
280                 error = suspend_ops->prepare();
281                 if (error)
282                         goto Resume_devices;
283         }
284
285         if (suspend_test(TEST_PLATFORM))
286                 goto Finish;
287
288         error = disable_nonboot_cpus();
289         if (!error && !suspend_test(TEST_CPUS))
290                 suspend_enter(state);
291
292         enable_nonboot_cpus();
293  Finish:
294         if (suspend_ops->finish)
295                 suspend_ops->finish();
296  Resume_devices:
297         device_resume();
298  Resume_console:
299         resume_console();
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         thaw_processes();
312         pm_restore_console();
313         pm_notifier_call_chain(PM_POST_SUSPEND);
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("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 #ifdef 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);