6096c71b182b04d59be7ff97ef770bb8bc6f6e61
[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/suspend.h>
12 #include <linux/kobject.h>
13 #include <linux/string.h>
14 #include <linux/delay.h>
15 #include <linux/errno.h>
16 #include <linux/init.h>
17 #include <linux/pm.h>
18 #include <linux/console.h>
19 #include <linux/cpu.h>
20 #include <linux/resume-trace.h>
21 #include <linux/freezer.h>
22
23 #include "power.h"
24
25 /*This is just an arbitrary number */
26 #define FREE_PAGE_NUMBER (100)
27
28 DECLARE_MUTEX(pm_sem);
29
30 struct pm_ops *pm_ops;
31 suspend_disk_method_t pm_disk_mode = PM_DISK_SHUTDOWN;
32
33 /**
34  *      pm_set_ops - Set the global power method table. 
35  *      @ops:   Pointer to ops structure.
36  */
37
38 void pm_set_ops(struct pm_ops * ops)
39 {
40         down(&pm_sem);
41         pm_ops = ops;
42         up(&pm_sem);
43 }
44
45
46 /**
47  *      suspend_prepare - Do prep work before entering low-power state.
48  *      @state:         State we're entering.
49  *
50  *      This is common code that is called for each state that we're 
51  *      entering. Allocate a console, stop all processes, then make sure
52  *      the platform can enter the requested state.
53  */
54
55 static int suspend_prepare(suspend_state_t state)
56 {
57         int error;
58         unsigned int free_pages;
59
60         if (!pm_ops || !pm_ops->enter)
61                 return -EPERM;
62
63         pm_prepare_console();
64
65         error = disable_nonboot_cpus();
66         if (error)
67                 goto Enable_cpu;
68
69         if (freeze_processes()) {
70                 error = -EAGAIN;
71                 goto Thaw;
72         }
73
74         if ((free_pages = nr_free_pages()) < FREE_PAGE_NUMBER) {
75                 pr_debug("PM: free some memory\n");
76                 shrink_all_memory(FREE_PAGE_NUMBER - free_pages);
77                 if (nr_free_pages() < FREE_PAGE_NUMBER) {
78                         error = -ENOMEM;
79                         printk(KERN_ERR "PM: No enough memory\n");
80                         goto Thaw;
81                 }
82         }
83
84         if (pm_ops->prepare) {
85                 if ((error = pm_ops->prepare(state)))
86                         goto Thaw;
87         }
88
89         suspend_console();
90         if ((error = device_suspend(PMSG_SUSPEND))) {
91                 printk(KERN_ERR "Some devices failed to suspend\n");
92                 goto Finish;
93         }
94         return 0;
95  Finish:
96         if (pm_ops->finish)
97                 pm_ops->finish(state);
98  Thaw:
99         thaw_processes();
100  Enable_cpu:
101         enable_nonboot_cpus();
102         pm_restore_console();
103         return error;
104 }
105
106
107 int suspend_enter(suspend_state_t state)
108 {
109         int error = 0;
110         unsigned long flags;
111
112         local_irq_save(flags);
113
114         if ((error = device_power_down(PMSG_SUSPEND))) {
115                 printk(KERN_ERR "Some devices failed to power down\n");
116                 goto Done;
117         }
118         error = pm_ops->enter(state);
119         device_power_up();
120  Done:
121         local_irq_restore(flags);
122         return error;
123 }
124
125
126 /**
127  *      suspend_finish - Do final work before exiting suspend sequence.
128  *      @state:         State we're coming out of.
129  *
130  *      Call platform code to clean up, restart processes, and free the 
131  *      console that we've allocated. This is not called for suspend-to-disk.
132  */
133
134 static void suspend_finish(suspend_state_t state)
135 {
136         device_resume();
137         resume_console();
138         thaw_processes();
139         enable_nonboot_cpus();
140         if (pm_ops && pm_ops->finish)
141                 pm_ops->finish(state);
142         pm_restore_console();
143 }
144
145
146
147
148 static const char * const pm_states[PM_SUSPEND_MAX] = {
149         [PM_SUSPEND_STANDBY]    = "standby",
150         [PM_SUSPEND_MEM]        = "mem",
151 #ifdef CONFIG_SOFTWARE_SUSPEND
152         [PM_SUSPEND_DISK]       = "disk",
153 #endif
154 };
155
156 static inline int valid_state(suspend_state_t state)
157 {
158         /* Suspend-to-disk does not really need low-level support.
159          * It can work with reboot if needed. */
160         if (state == PM_SUSPEND_DISK)
161                 return 1;
162
163         if (pm_ops && pm_ops->valid && !pm_ops->valid(state))
164                 return 0;
165         return 1;
166 }
167
168
169 /**
170  *      enter_state - Do common work of entering low-power state.
171  *      @state:         pm_state structure for state we're entering.
172  *
173  *      Make sure we're the only ones trying to enter a sleep state. Fail
174  *      if someone has beat us to it, since we don't want anything weird to
175  *      happen when we wake up.
176  *      Then, do the setup for suspend, enter the state, and cleaup (after
177  *      we've woken up).
178  */
179
180 static int enter_state(suspend_state_t state)
181 {
182         int error;
183
184         if (!valid_state(state))
185                 return -ENODEV;
186         if (down_trylock(&pm_sem))
187                 return -EBUSY;
188
189         if (state == PM_SUSPEND_DISK) {
190                 error = pm_suspend_disk();
191                 goto Unlock;
192         }
193
194         pr_debug("PM: Preparing system for %s sleep\n", pm_states[state]);
195         if ((error = suspend_prepare(state)))
196                 goto Unlock;
197
198         pr_debug("PM: Entering %s sleep\n", pm_states[state]);
199         error = suspend_enter(state);
200
201         pr_debug("PM: Finishing wakeup.\n");
202         suspend_finish(state);
203  Unlock:
204         up(&pm_sem);
205         return error;
206 }
207
208 /*
209  * This is main interface to the outside world. It needs to be
210  * called from process context.
211  */
212 int software_suspend(void)
213 {
214         return enter_state(PM_SUSPEND_DISK);
215 }
216
217
218 /**
219  *      pm_suspend - Externally visible function for suspending system.
220  *      @state:         Enumarted value of state to enter.
221  *
222  *      Determine whether or not value is within range, get state 
223  *      structure, and enter (above).
224  */
225
226 int pm_suspend(suspend_state_t state)
227 {
228         if (state > PM_SUSPEND_ON && state <= PM_SUSPEND_MAX)
229                 return enter_state(state);
230         return -EINVAL;
231 }
232
233
234
235 decl_subsys(power,NULL,NULL);
236
237
238 /**
239  *      state - control system power state.
240  *
241  *      show() returns what states are supported, which is hard-coded to
242  *      'standby' (Power-On Suspend), 'mem' (Suspend-to-RAM), and
243  *      'disk' (Suspend-to-Disk).
244  *
245  *      store() accepts one of those strings, translates it into the 
246  *      proper enumerated value, and initiates a suspend transition.
247  */
248
249 static ssize_t state_show(struct subsystem * subsys, char * buf)
250 {
251         int i;
252         char * s = buf;
253
254         for (i = 0; i < PM_SUSPEND_MAX; i++) {
255                 if (pm_states[i] && valid_state(i))
256                         s += sprintf(s,"%s ", pm_states[i]);
257         }
258         s += sprintf(s,"\n");
259         return (s - buf);
260 }
261
262 static ssize_t state_store(struct subsystem * subsys, const char * buf, size_t n)
263 {
264         suspend_state_t state = PM_SUSPEND_STANDBY;
265         const char * const *s;
266         char *p;
267         int error;
268         int len;
269
270         p = memchr(buf, '\n', n);
271         len = p ? p - buf : n;
272
273         for (s = &pm_states[state]; state < PM_SUSPEND_MAX; s++, state++) {
274                 if (*s && !strncmp(buf, *s, len))
275                         break;
276         }
277         if (state < PM_SUSPEND_MAX && *s)
278                 error = enter_state(state);
279         else
280                 error = -EINVAL;
281         return error ? error : n;
282 }
283
284 power_attr(state);
285
286 #ifdef CONFIG_PM_TRACE
287 int pm_trace_enabled;
288
289 static ssize_t pm_trace_show(struct subsystem * subsys, char * buf)
290 {
291         return sprintf(buf, "%d\n", pm_trace_enabled);
292 }
293
294 static ssize_t
295 pm_trace_store(struct subsystem * subsys, const char * buf, size_t n)
296 {
297         int val;
298
299         if (sscanf(buf, "%d", &val) == 1) {
300                 pm_trace_enabled = !!val;
301                 return n;
302         }
303         return -EINVAL;
304 }
305
306 power_attr(pm_trace);
307
308 static struct attribute * g[] = {
309         &state_attr.attr,
310         &pm_trace_attr.attr,
311         NULL,
312 };
313 #else
314 static struct attribute * g[] = {
315         &state_attr.attr,
316         NULL,
317 };
318 #endif /* CONFIG_PM_TRACE */
319
320 static struct attribute_group attr_group = {
321         .attrs = g,
322 };
323
324
325 static int __init pm_init(void)
326 {
327         int error = subsystem_register(&power_subsys);
328         if (!error)
329                 error = sysfs_create_group(&power_subsys.kset.kobj,&attr_group);
330         return error;
331 }
332
333 core_initcall(pm_init);