make kernel/power/main.c:suspend_enter() static
[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
24 #include "power.h"
25
26 BLOCKING_NOTIFIER_HEAD(pm_chain_head);
27
28 DEFINE_MUTEX(pm_mutex);
29
30 #ifdef CONFIG_SUSPEND
31
32 /* This is just an arbitrary number */
33 #define FREE_PAGE_NUMBER (100)
34
35 struct pm_ops *pm_ops;
36
37 /**
38  *      pm_set_ops - Set the global power method table. 
39  *      @ops:   Pointer to ops structure.
40  */
41
42 void pm_set_ops(struct pm_ops * ops)
43 {
44         mutex_lock(&pm_mutex);
45         pm_ops = ops;
46         mutex_unlock(&pm_mutex);
47 }
48
49 /**
50  * pm_valid_only_mem - generic memory-only valid callback
51  *
52  * pm_ops drivers that implement mem suspend only and only need
53  * to check for that in their .valid callback can use this instead
54  * of rolling their own .valid callback.
55  */
56 int pm_valid_only_mem(suspend_state_t state)
57 {
58         return state == PM_SUSPEND_MEM;
59 }
60
61
62 static inline void pm_finish(suspend_state_t state)
63 {
64         if (pm_ops->finish)
65                 pm_ops->finish(state);
66 }
67
68 /**
69  *      suspend_prepare - Do prep work before entering low-power state.
70  *
71  *      This is common code that is called for each state that we're entering.
72  *      Run suspend notifiers, allocate a console and stop all processes.
73  */
74 static int suspend_prepare(void)
75 {
76         int error;
77         unsigned int free_pages;
78
79         if (!pm_ops || !pm_ops->enter)
80                 return -EPERM;
81
82         error = pm_notifier_call_chain(PM_SUSPEND_PREPARE);
83         if (error)
84                 goto Finish;
85
86         pm_prepare_console();
87
88         if (freeze_processes()) {
89                 error = -EAGAIN;
90                 goto Thaw;
91         }
92
93         free_pages = global_page_state(NR_FREE_PAGES);
94         if (free_pages < FREE_PAGE_NUMBER) {
95                 pr_debug("PM: free some memory\n");
96                 shrink_all_memory(FREE_PAGE_NUMBER - free_pages);
97                 if (nr_free_pages() < FREE_PAGE_NUMBER) {
98                         error = -ENOMEM;
99                         printk(KERN_ERR "PM: No enough memory\n");
100                 }
101         }
102         if (!error)
103                 return 0;
104
105  Thaw:
106         thaw_processes();
107         pm_restore_console();
108  Finish:
109         pm_notifier_call_chain(PM_POST_SUSPEND);
110         return error;
111 }
112
113 /* default implementation */
114 void __attribute__ ((weak)) arch_suspend_disable_irqs(void)
115 {
116         local_irq_disable();
117 }
118
119 /* default implementation */
120 void __attribute__ ((weak)) arch_suspend_enable_irqs(void)
121 {
122         local_irq_enable();
123 }
124
125 /**
126  *      suspend_enter - enter the desired system sleep state.
127  *      @state:         state to enter
128  *
129  *      This function should be called after devices have been suspended.
130  */
131 static int suspend_enter(suspend_state_t state)
132 {
133         int error = 0;
134
135         arch_suspend_disable_irqs();
136         BUG_ON(!irqs_disabled());
137
138         if ((error = device_power_down(PMSG_SUSPEND))) {
139                 printk(KERN_ERR "Some devices failed to power down\n");
140                 goto Done;
141         }
142         error = pm_ops->enter(state);
143         device_power_up();
144  Done:
145         arch_suspend_enable_irqs();
146         BUG_ON(irqs_disabled());
147         return error;
148 }
149
150 /**
151  *      suspend_devices_and_enter - suspend devices and enter the desired system sleep
152  *                        state.
153  *      @state:           state to enter
154  */
155 int suspend_devices_and_enter(suspend_state_t state)
156 {
157         int error;
158
159         if (!pm_ops)
160                 return -ENOSYS;
161
162         if (pm_ops->set_target) {
163                 error = pm_ops->set_target(state);
164                 if (error)
165                         return error;
166         }
167         suspend_console();
168         error = device_suspend(PMSG_SUSPEND);
169         if (error) {
170                 printk(KERN_ERR "Some devices failed to suspend\n");
171                 goto Resume_console;
172         }
173         if (pm_ops->prepare) {
174                 error = pm_ops->prepare(state);
175                 if (error)
176                         goto Resume_devices;
177         }
178         error = disable_nonboot_cpus();
179         if (!error)
180                 suspend_enter(state);
181
182         enable_nonboot_cpus();
183         pm_finish(state);
184  Resume_devices:
185         device_resume();
186  Resume_console:
187         resume_console();
188         return error;
189 }
190
191 /**
192  *      suspend_finish - Do final work before exiting suspend sequence.
193  *
194  *      Call platform code to clean up, restart processes, and free the 
195  *      console that we've allocated. This is not called for suspend-to-disk.
196  */
197 static void suspend_finish(void)
198 {
199         thaw_processes();
200         pm_restore_console();
201         pm_notifier_call_chain(PM_POST_SUSPEND);
202 }
203
204
205
206
207 static const char * const pm_states[PM_SUSPEND_MAX] = {
208         [PM_SUSPEND_STANDBY]    = "standby",
209         [PM_SUSPEND_MEM]        = "mem",
210 };
211
212 static inline int valid_state(suspend_state_t state)
213 {
214         /* All states need lowlevel support and need to be valid
215          * to the lowlevel implementation, no valid callback
216          * implies that none are valid. */
217         if (!pm_ops || !pm_ops->valid || !pm_ops->valid(state))
218                 return 0;
219         return 1;
220 }
221
222
223 /**
224  *      enter_state - Do common work of entering low-power state.
225  *      @state:         pm_state structure for state we're entering.
226  *
227  *      Make sure we're the only ones trying to enter a sleep state. Fail
228  *      if someone has beat us to it, since we don't want anything weird to
229  *      happen when we wake up.
230  *      Then, do the setup for suspend, enter the state, and cleaup (after
231  *      we've woken up).
232  */
233 static int enter_state(suspend_state_t state)
234 {
235         int error;
236
237         if (!valid_state(state))
238                 return -ENODEV;
239         if (!mutex_trylock(&pm_mutex))
240                 return -EBUSY;
241
242         pr_debug("PM: Preparing system for %s sleep\n", pm_states[state]);
243         if ((error = suspend_prepare()))
244                 goto Unlock;
245
246         pr_debug("PM: Entering %s sleep\n", pm_states[state]);
247         error = suspend_devices_and_enter(state);
248
249         pr_debug("PM: Finishing wakeup.\n");
250         suspend_finish();
251  Unlock:
252         mutex_unlock(&pm_mutex);
253         return error;
254 }
255
256
257 /**
258  *      pm_suspend - Externally visible function for suspending system.
259  *      @state:         Enumerated value of state to enter.
260  *
261  *      Determine whether or not value is within range, get state 
262  *      structure, and enter (above).
263  */
264
265 int pm_suspend(suspend_state_t state)
266 {
267         if (state > PM_SUSPEND_ON && state <= PM_SUSPEND_MAX)
268                 return enter_state(state);
269         return -EINVAL;
270 }
271
272 EXPORT_SYMBOL(pm_suspend);
273
274 #endif /* CONFIG_SUSPEND */
275
276 decl_subsys(power,NULL,NULL);
277
278
279 /**
280  *      state - control system power state.
281  *
282  *      show() returns what states are supported, which is hard-coded to
283  *      'standby' (Power-On Suspend), 'mem' (Suspend-to-RAM), and
284  *      'disk' (Suspend-to-Disk).
285  *
286  *      store() accepts one of those strings, translates it into the 
287  *      proper enumerated value, and initiates a suspend transition.
288  */
289
290 static ssize_t state_show(struct kset *kset, char *buf)
291 {
292         char *s = buf;
293 #ifdef CONFIG_SUSPEND
294         int i;
295
296         for (i = 0; i < PM_SUSPEND_MAX; i++) {
297                 if (pm_states[i] && valid_state(i))
298                         s += sprintf(s,"%s ", pm_states[i]);
299         }
300 #endif
301 #ifdef CONFIG_HIBERNATION
302         s += sprintf(s, "%s\n", "disk");
303 #else
304         if (s != buf)
305                 /* convert the last space to a newline */
306                 *(s-1) = '\n';
307 #endif
308         return (s - buf);
309 }
310
311 static ssize_t state_store(struct kset *kset, const char *buf, size_t n)
312 {
313 #ifdef CONFIG_SUSPEND
314         suspend_state_t state = PM_SUSPEND_STANDBY;
315         const char * const *s;
316 #endif
317         char *p;
318         int len;
319         int error = -EINVAL;
320
321         p = memchr(buf, '\n', n);
322         len = p ? p - buf : n;
323
324         /* First, check if we are requested to hibernate */
325         if (len == 4 && !strncmp(buf, "disk", len)) {
326                 error = hibernate();
327   goto Exit;
328         }
329
330 #ifdef CONFIG_SUSPEND
331         for (s = &pm_states[state]; state < PM_SUSPEND_MAX; s++, state++) {
332                 if (*s && len == strlen(*s) && !strncmp(buf, *s, len))
333                         break;
334         }
335         if (state < PM_SUSPEND_MAX && *s)
336                 error = enter_state(state);
337 #endif
338
339  Exit:
340         return error ? error : n;
341 }
342
343 power_attr(state);
344
345 #ifdef CONFIG_PM_TRACE
346 int pm_trace_enabled;
347
348 static ssize_t pm_trace_show(struct kset *kset, char *buf)
349 {
350         return sprintf(buf, "%d\n", pm_trace_enabled);
351 }
352
353 static ssize_t
354 pm_trace_store(struct kset *kset, const char *buf, size_t n)
355 {
356         int val;
357
358         if (sscanf(buf, "%d", &val) == 1) {
359                 pm_trace_enabled = !!val;
360                 return n;
361         }
362         return -EINVAL;
363 }
364
365 power_attr(pm_trace);
366
367 static struct attribute * g[] = {
368         &state_attr.attr,
369         &pm_trace_attr.attr,
370         NULL,
371 };
372 #else
373 static struct attribute * g[] = {
374         &state_attr.attr,
375         NULL,
376 };
377 #endif /* CONFIG_PM_TRACE */
378
379 static struct attribute_group attr_group = {
380         .attrs = g,
381 };
382
383
384 static int __init pm_init(void)
385 {
386         int error = subsystem_register(&power_subsys);
387         if (!error)
388                 error = sysfs_create_group(&power_subsys.kobj,&attr_group);
389         return error;
390 }
391
392 core_initcall(pm_init);