Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/dtor/input
[linux-2.6] / 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/pm.h>
19 #include <linux/console.h>
20 #include <linux/cpu.h>
21 #include <linux/resume-trace.h>
22 #include <linux/freezer.h>
23 #include <linux/vmstat.h>
24
25 #include "power.h"
26
27 /*This is just an arbitrary number */
28 #define FREE_PAGE_NUMBER (100)
29
30 DEFINE_MUTEX(pm_mutex);
31
32 struct pm_ops *pm_ops;
33
34 /**
35  *      pm_set_ops - Set the global power method table. 
36  *      @ops:   Pointer to ops structure.
37  */
38
39 void pm_set_ops(struct pm_ops * ops)
40 {
41         mutex_lock(&pm_mutex);
42         pm_ops = ops;
43         mutex_unlock(&pm_mutex);
44 }
45
46 /**
47  * pm_valid_only_mem - generic memory-only valid callback
48  *
49  * pm_ops drivers that implement mem suspend only and only need
50  * to check for that in their .valid callback can use this instead
51  * of rolling their own .valid callback.
52  */
53 int pm_valid_only_mem(suspend_state_t state)
54 {
55         return state == PM_SUSPEND_MEM;
56 }
57
58
59 static inline void pm_finish(suspend_state_t state)
60 {
61         if (pm_ops->finish)
62                 pm_ops->finish(state);
63 }
64
65 /**
66  *      suspend_prepare - Do prep work before entering low-power state.
67  *      @state:         State we're entering.
68  *
69  *      This is common code that is called for each state that we're 
70  *      entering. Allocate a console, stop all processes, then make sure
71  *      the platform can enter the requested state.
72  */
73
74 static int suspend_prepare(suspend_state_t state)
75 {
76         int error;
77         unsigned int free_pages;
78
79         if (!pm_ops || !pm_ops->enter)
80                 return -EPERM;
81
82         pm_prepare_console();
83
84         if (freeze_processes()) {
85                 error = -EAGAIN;
86                 goto Thaw;
87         }
88
89         if ((free_pages = global_page_state(NR_FREE_PAGES))
90                         < FREE_PAGE_NUMBER) {
91                 pr_debug("PM: free some memory\n");
92                 shrink_all_memory(FREE_PAGE_NUMBER - free_pages);
93                 if (nr_free_pages() < FREE_PAGE_NUMBER) {
94                         error = -ENOMEM;
95                         printk(KERN_ERR "PM: No enough memory\n");
96                         goto Thaw;
97                 }
98         }
99
100         suspend_console();
101         error = device_suspend(PMSG_SUSPEND);
102         if (error) {
103                 printk(KERN_ERR "Some devices failed to suspend\n");
104                 goto Resume_console;
105         }
106         if (pm_ops->prepare) {
107                 if ((error = pm_ops->prepare(state)))
108                         goto Resume_devices;
109         }
110
111         error = disable_nonboot_cpus();
112         if (!error)
113                 return 0;
114
115         enable_nonboot_cpus();
116         pm_finish(state);
117  Resume_devices:
118         device_resume();
119  Resume_console:
120         resume_console();
121  Thaw:
122         thaw_processes();
123         pm_restore_console();
124         return error;
125 }
126
127 /* default implementation */
128 void __attribute__ ((weak)) arch_suspend_disable_irqs(void)
129 {
130         local_irq_disable();
131 }
132
133 /* default implementation */
134 void __attribute__ ((weak)) arch_suspend_enable_irqs(void)
135 {
136         local_irq_enable();
137 }
138
139 int suspend_enter(suspend_state_t state)
140 {
141         int error = 0;
142
143         arch_suspend_disable_irqs();
144         BUG_ON(!irqs_disabled());
145
146         if ((error = device_power_down(PMSG_SUSPEND))) {
147                 printk(KERN_ERR "Some devices failed to power down\n");
148                 goto Done;
149         }
150         error = pm_ops->enter(state);
151         device_power_up();
152  Done:
153         arch_suspend_enable_irqs();
154         BUG_ON(irqs_disabled());
155         return error;
156 }
157
158
159 /**
160  *      suspend_finish - Do final work before exiting suspend sequence.
161  *      @state:         State we're coming out of.
162  *
163  *      Call platform code to clean up, restart processes, and free the 
164  *      console that we've allocated. This is not called for suspend-to-disk.
165  */
166
167 static void suspend_finish(suspend_state_t state)
168 {
169         enable_nonboot_cpus();
170         pm_finish(state);
171         device_resume();
172         resume_console();
173         thaw_processes();
174         pm_restore_console();
175 }
176
177
178
179
180 static const char * const pm_states[PM_SUSPEND_MAX] = {
181         [PM_SUSPEND_STANDBY]    = "standby",
182         [PM_SUSPEND_MEM]        = "mem",
183 };
184
185 static inline int valid_state(suspend_state_t state)
186 {
187         /* All states need lowlevel support and need to be valid
188          * to the lowlevel implementation, no valid callback
189          * implies that none are valid. */
190         if (!pm_ops || !pm_ops->valid || !pm_ops->valid(state))
191                 return 0;
192         return 1;
193 }
194
195
196 /**
197  *      enter_state - Do common work of entering low-power state.
198  *      @state:         pm_state structure for state we're entering.
199  *
200  *      Make sure we're the only ones trying to enter a sleep state. Fail
201  *      if someone has beat us to it, since we don't want anything weird to
202  *      happen when we wake up.
203  *      Then, do the setup for suspend, enter the state, and cleaup (after
204  *      we've woken up).
205  */
206
207 static int enter_state(suspend_state_t state)
208 {
209         int error;
210
211         if (!valid_state(state))
212                 return -ENODEV;
213         if (!mutex_trylock(&pm_mutex))
214                 return -EBUSY;
215
216         pr_debug("PM: Preparing system for %s sleep\n", pm_states[state]);
217         if ((error = suspend_prepare(state)))
218                 goto Unlock;
219
220         pr_debug("PM: Entering %s sleep\n", pm_states[state]);
221         error = suspend_enter(state);
222
223         pr_debug("PM: Finishing wakeup.\n");
224         suspend_finish(state);
225  Unlock:
226         mutex_unlock(&pm_mutex);
227         return error;
228 }
229
230
231 /**
232  *      pm_suspend - Externally visible function for suspending system.
233  *      @state:         Enumerated value of state to enter.
234  *
235  *      Determine whether or not value is within range, get state 
236  *      structure, and enter (above).
237  */
238
239 int pm_suspend(suspend_state_t state)
240 {
241         if (state > PM_SUSPEND_ON && state <= PM_SUSPEND_MAX)
242                 return enter_state(state);
243         return -EINVAL;
244 }
245
246 EXPORT_SYMBOL(pm_suspend);
247
248 decl_subsys(power,NULL,NULL);
249
250
251 /**
252  *      state - control system power state.
253  *
254  *      show() returns what states are supported, which is hard-coded to
255  *      'standby' (Power-On Suspend), 'mem' (Suspend-to-RAM), and
256  *      'disk' (Suspend-to-Disk).
257  *
258  *      store() accepts one of those strings, translates it into the 
259  *      proper enumerated value, and initiates a suspend transition.
260  */
261
262 static ssize_t state_show(struct kset *kset, char *buf)
263 {
264         int i;
265         char * s = buf;
266
267         for (i = 0; i < PM_SUSPEND_MAX; i++) {
268                 if (pm_states[i] && valid_state(i))
269                         s += sprintf(s,"%s ", pm_states[i]);
270         }
271 #ifdef CONFIG_SOFTWARE_SUSPEND
272         s += sprintf(s, "%s\n", "disk");
273 #else
274         if (s != buf)
275                 /* convert the last space to a newline */
276                 *(s-1) = '\n';
277 #endif
278         return (s - buf);
279 }
280
281 static ssize_t state_store(struct kset *kset, const char *buf, size_t n)
282 {
283         suspend_state_t state = PM_SUSPEND_STANDBY;
284         const char * const *s;
285         char *p;
286         int error;
287         int len;
288
289         p = memchr(buf, '\n', n);
290         len = p ? p - buf : n;
291
292         /* First, check if we are requested to hibernate */
293         if (len == 4 && !strncmp(buf, "disk", len)) {
294                 error = hibernate();
295                 return error ? error : n;
296         }
297
298         for (s = &pm_states[state]; state < PM_SUSPEND_MAX; s++, state++) {
299                 if (*s && len == strlen(*s) && !strncmp(buf, *s, len))
300                         break;
301         }
302         if (state < PM_SUSPEND_MAX && *s)
303                 error = enter_state(state);
304         else
305                 error = -EINVAL;
306         return error ? error : n;
307 }
308
309 power_attr(state);
310
311 #ifdef CONFIG_PM_TRACE
312 int pm_trace_enabled;
313
314 static ssize_t pm_trace_show(struct kset *kset, char *buf)
315 {
316         return sprintf(buf, "%d\n", pm_trace_enabled);
317 }
318
319 static ssize_t
320 pm_trace_store(struct kset *kset, const char *buf, size_t n)
321 {
322         int val;
323
324         if (sscanf(buf, "%d", &val) == 1) {
325                 pm_trace_enabled = !!val;
326                 return n;
327         }
328         return -EINVAL;
329 }
330
331 power_attr(pm_trace);
332
333 static struct attribute * g[] = {
334         &state_attr.attr,
335         &pm_trace_attr.attr,
336         NULL,
337 };
338 #else
339 static struct attribute * g[] = {
340         &state_attr.attr,
341         NULL,
342 };
343 #endif /* CONFIG_PM_TRACE */
344
345 static struct attribute_group attr_group = {
346         .attrs = g,
347 };
348
349
350 static int __init pm_init(void)
351 {
352         int error = subsystem_register(&power_subsys);
353         if (!error)
354                 error = sysfs_create_group(&power_subsys.kobj,&attr_group);
355         return error;
356 }
357
358 core_initcall(pm_init);