[PATCH] sleep: Fix oops in enter_state
[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
19
20 #include "power.h"
21
22 /*This is just an arbitrary number */
23 #define FREE_PAGE_NUMBER (100)
24
25 DECLARE_MUTEX(pm_sem);
26
27 struct pm_ops * pm_ops = NULL;
28 suspend_disk_method_t pm_disk_mode = PM_DISK_SHUTDOWN;
29
30 /**
31  *      pm_set_ops - Set the global power method table. 
32  *      @ops:   Pointer to ops structure.
33  */
34
35 void pm_set_ops(struct pm_ops * ops)
36 {
37         down(&pm_sem);
38         pm_ops = ops;
39         up(&pm_sem);
40 }
41
42
43 /**
44  *      suspend_prepare - Do prep work before entering low-power state.
45  *      @state:         State we're entering.
46  *
47  *      This is common code that is called for each state that we're 
48  *      entering. Allocate a console, stop all processes, then make sure
49  *      the platform can enter the requested state.
50  */
51
52 static int suspend_prepare(suspend_state_t state)
53 {
54         int error = 0;
55         unsigned int free_pages;
56
57         if (!pm_ops || !pm_ops->enter)
58                 return -EPERM;
59
60         pm_prepare_console();
61
62         disable_nonboot_cpus();
63
64         if (num_online_cpus() != 1) {
65                 error = -EPERM;
66                 goto Enable_cpu;
67         }
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         if ((error = device_suspend(PMSG_SUSPEND))) {
90                 printk(KERN_ERR "Some devices failed to suspend\n");
91                 goto Finish;
92         }
93         return 0;
94  Finish:
95         if (pm_ops->finish)
96                 pm_ops->finish(state);
97  Thaw:
98         thaw_processes();
99  Enable_cpu:
100         enable_nonboot_cpus();
101         pm_restore_console();
102         return error;
103 }
104
105
106 static int suspend_enter(suspend_state_t state)
107 {
108         int error = 0;
109         unsigned long flags;
110
111         local_irq_save(flags);
112
113         if ((error = device_power_down(PMSG_SUSPEND))) {
114                 printk(KERN_ERR "Some devices failed to power down\n");
115                 goto Done;
116         }
117         error = pm_ops->enter(state);
118         device_power_up();
119  Done:
120         local_irq_restore(flags);
121         return error;
122 }
123
124
125 /**
126  *      suspend_finish - Do final work before exiting suspend sequence.
127  *      @state:         State we're coming out of.
128  *
129  *      Call platform code to clean up, restart processes, and free the 
130  *      console that we've allocated. This is not called for suspend-to-disk.
131  */
132
133 static void suspend_finish(suspend_state_t state)
134 {
135         device_resume();
136         if (pm_ops && pm_ops->finish)
137                 pm_ops->finish(state);
138         thaw_processes();
139         enable_nonboot_cpus();
140         pm_restore_console();
141 }
142
143
144
145
146 static char *pm_states[PM_SUSPEND_MAX] = {
147         [PM_SUSPEND_STANDBY]    = "standby",
148         [PM_SUSPEND_MEM]        = "mem",
149 #ifdef CONFIG_SOFTWARE_SUSPEND
150         [PM_SUSPEND_DISK]       = "disk",
151 #endif
152 };
153
154
155 /**
156  *      enter_state - Do common work of entering low-power state.
157  *      @state:         pm_state structure for state we're entering.
158  *
159  *      Make sure we're the only ones trying to enter a sleep state. Fail
160  *      if someone has beat us to it, since we don't want anything weird to
161  *      happen when we wake up.
162  *      Then, do the setup for suspend, enter the state, and cleaup (after
163  *      we've woken up).
164  */
165
166 static int enter_state(suspend_state_t state)
167 {
168         int error;
169
170         if (pm_ops && pm_ops->valid && !pm_ops->valid(state))
171                 return -ENODEV;
172         if (down_trylock(&pm_sem))
173                 return -EBUSY;
174
175         if (state == PM_SUSPEND_DISK) {
176                 error = pm_suspend_disk();
177                 goto Unlock;
178         }
179
180         pr_debug("PM: Preparing system for %s sleep\n", pm_states[state]);
181         if ((error = suspend_prepare(state)))
182                 goto Unlock;
183
184         pr_debug("PM: Entering %s sleep\n", pm_states[state]);
185         error = suspend_enter(state);
186
187         pr_debug("PM: Finishing wakeup.\n");
188         suspend_finish(state);
189  Unlock:
190         up(&pm_sem);
191         return error;
192 }
193
194 /*
195  * This is main interface to the outside world. It needs to be
196  * called from process context.
197  */
198 int software_suspend(void)
199 {
200         return enter_state(PM_SUSPEND_DISK);
201 }
202
203
204 /**
205  *      pm_suspend - Externally visible function for suspending system.
206  *      @state:         Enumarted value of state to enter.
207  *
208  *      Determine whether or not value is within range, get state 
209  *      structure, and enter (above).
210  */
211
212 int pm_suspend(suspend_state_t state)
213 {
214         if (state > PM_SUSPEND_ON && state <= PM_SUSPEND_MAX)
215                 return enter_state(state);
216         return -EINVAL;
217 }
218
219
220
221 decl_subsys(power,NULL,NULL);
222
223
224 /**
225  *      state - control system power state.
226  *
227  *      show() returns what states are supported, which is hard-coded to
228  *      'standby' (Power-On Suspend), 'mem' (Suspend-to-RAM), and
229  *      'disk' (Suspend-to-Disk).
230  *
231  *      store() accepts one of those strings, translates it into the 
232  *      proper enumerated value, and initiates a suspend transition.
233  */
234
235 static ssize_t state_show(struct subsystem * subsys, char * buf)
236 {
237         int i;
238         char * s = buf;
239
240         for (i = 0; i < PM_SUSPEND_MAX; i++) {
241                 if (pm_states[i] && pm_ops && (!pm_ops->valid
242                         ||(pm_ops->valid && pm_ops->valid(i))))
243                         s += sprintf(s,"%s ",pm_states[i]);
244         }
245         s += sprintf(s,"\n");
246         return (s - buf);
247 }
248
249 static ssize_t state_store(struct subsystem * subsys, const char * buf, size_t n)
250 {
251         suspend_state_t state = PM_SUSPEND_STANDBY;
252         char ** s;
253         char *p;
254         int error;
255         int len;
256
257         p = memchr(buf, '\n', n);
258         len = p ? p - buf : n;
259
260         for (s = &pm_states[state]; state < PM_SUSPEND_MAX; s++, state++) {
261                 if (*s && !strncmp(buf, *s, len))
262                         break;
263         }
264         if (*s)
265                 error = enter_state(state);
266         else
267                 error = -EINVAL;
268         return error ? error : n;
269 }
270
271 power_attr(state);
272
273 static struct attribute * g[] = {
274         &state_attr.attr,
275         NULL,
276 };
277
278 static struct attribute_group attr_group = {
279         .attrs = g,
280 };
281
282
283 static int __init pm_init(void)
284 {
285         int error = subsystem_register(&power_subsys);
286         if (!error)
287                 error = sysfs_create_group(&power_subsys.kset.kobj,&attr_group);
288         return error;
289 }
290
291 core_initcall(pm_init);