[ACPI] merge acpi-2.6.12 branch into latest Linux 2.6.13-rc...
[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[] = {
147         [PM_SUSPEND_STANDBY]    = "standby",
148         [PM_SUSPEND_MEM]        = "mem",
149         [PM_SUSPEND_DISK]       = "disk",
150         NULL,
151 };
152
153
154 /**
155  *      enter_state - Do common work of entering low-power state.
156  *      @state:         pm_state structure for state we're entering.
157  *
158  *      Make sure we're the only ones trying to enter a sleep state. Fail
159  *      if someone has beat us to it, since we don't want anything weird to
160  *      happen when we wake up.
161  *      Then, do the setup for suspend, enter the state, and cleaup (after
162  *      we've woken up).
163  */
164
165 static int enter_state(suspend_state_t state)
166 {
167         int error;
168
169         if (down_trylock(&pm_sem))
170                 return -EBUSY;
171
172         if (state == PM_SUSPEND_DISK) {
173                 error = pm_suspend_disk();
174                 goto Unlock;
175         }
176
177         pr_debug("PM: Preparing system for %s sleep\n", pm_states[state]);
178         if ((error = suspend_prepare(state)))
179                 goto Unlock;
180
181         pr_debug("PM: Entering %s sleep\n", pm_states[state]);
182         error = suspend_enter(state);
183
184         pr_debug("PM: Finishing wakeup.\n");
185         suspend_finish(state);
186  Unlock:
187         up(&pm_sem);
188         return error;
189 }
190
191 /*
192  * This is main interface to the outside world. It needs to be
193  * called from process context.
194  */
195 int software_suspend(void)
196 {
197         return enter_state(PM_SUSPEND_DISK);
198 }
199
200
201 /**
202  *      pm_suspend - Externally visible function for suspending system.
203  *      @state:         Enumarted value of state to enter.
204  *
205  *      Determine whether or not value is within range, get state 
206  *      structure, and enter (above).
207  */
208
209 int pm_suspend(suspend_state_t state)
210 {
211         if (state > PM_SUSPEND_ON && state <= PM_SUSPEND_MAX)
212                 return enter_state(state);
213         return -EINVAL;
214 }
215
216
217
218 decl_subsys(power,NULL,NULL);
219
220
221 /**
222  *      state - control system power state.
223  *
224  *      show() returns what states are supported, which is hard-coded to
225  *      'standby' (Power-On Suspend), 'mem' (Suspend-to-RAM), and
226  *      'disk' (Suspend-to-Disk).
227  *
228  *      store() accepts one of those strings, translates it into the 
229  *      proper enumerated value, and initiates a suspend transition.
230  */
231
232 static ssize_t state_show(struct subsystem * subsys, char * buf)
233 {
234         int i;
235         char * s = buf;
236
237         for (i = 0; i < PM_SUSPEND_MAX; i++) {
238                 if (pm_states[i])
239                         s += sprintf(s,"%s ",pm_states[i]);
240         }
241         s += sprintf(s,"\n");
242         return (s - buf);
243 }
244
245 static ssize_t state_store(struct subsystem * subsys, const char * buf, size_t n)
246 {
247         suspend_state_t state = PM_SUSPEND_STANDBY;
248         char ** s;
249         char *p;
250         int error;
251         int len;
252
253         p = memchr(buf, '\n', n);
254         len = p ? p - buf : n;
255
256         for (s = &pm_states[state]; state < PM_SUSPEND_MAX; s++, state++) {
257                 if (*s && !strncmp(buf, *s, len))
258                         break;
259         }
260         if (*s)
261                 error = enter_state(state);
262         else
263                 error = -EINVAL;
264         return error ? error : n;
265 }
266
267 power_attr(state);
268
269 static struct attribute * g[] = {
270         &state_attr.attr,
271         NULL,
272 };
273
274 static struct attribute_group attr_group = {
275         .attrs = g,
276 };
277
278
279 static int __init pm_init(void)
280 {
281         int error = subsystem_register(&power_subsys);
282         if (!error)
283                 error = sysfs_create_group(&power_subsys.kset.kobj,&attr_group);
284         return error;
285 }
286
287 core_initcall(pm_init);