ACPI: S4: Use "platform" rather than "shutdown" mode by default
[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
22 #include "power.h"
23
24 /*This is just an arbitrary number */
25 #define FREE_PAGE_NUMBER (100)
26
27 DECLARE_MUTEX(pm_sem);
28
29 struct pm_ops *pm_ops;
30 suspend_disk_method_t pm_disk_mode = PM_DISK_PLATFORM;
31
32 /**
33  *      pm_set_ops - Set the global power method table. 
34  *      @ops:   Pointer to ops structure.
35  */
36
37 void pm_set_ops(struct pm_ops * ops)
38 {
39         down(&pm_sem);
40         pm_ops = ops;
41         up(&pm_sem);
42 }
43
44
45 /**
46  *      suspend_prepare - Do prep work before entering low-power state.
47  *      @state:         State we're entering.
48  *
49  *      This is common code that is called for each state that we're 
50  *      entering. Allocate a console, stop all processes, then make sure
51  *      the platform can enter the requested state.
52  */
53
54 static int suspend_prepare(suspend_state_t state)
55 {
56         int error;
57         unsigned int free_pages;
58
59         if (!pm_ops || !pm_ops->enter)
60                 return -EPERM;
61
62         pm_prepare_console();
63
64         error = disable_nonboot_cpus();
65         if (error)
66                 goto Enable_cpu;
67
68         if (freeze_processes()) {
69                 error = -EAGAIN;
70                 goto Thaw;
71         }
72
73         if ((free_pages = nr_free_pages()) < FREE_PAGE_NUMBER) {
74                 pr_debug("PM: free some memory\n");
75                 shrink_all_memory(FREE_PAGE_NUMBER - free_pages);
76                 if (nr_free_pages() < FREE_PAGE_NUMBER) {
77                         error = -ENOMEM;
78                         printk(KERN_ERR "PM: No enough memory\n");
79                         goto Thaw;
80                 }
81         }
82
83         if (pm_ops->prepare) {
84                 if ((error = pm_ops->prepare(state)))
85                         goto Thaw;
86         }
87
88         suspend_console();
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 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         resume_console();
137         thaw_processes();
138         enable_nonboot_cpus();
139         if (pm_ops && pm_ops->finish)
140                 pm_ops->finish(state);
141         pm_restore_console();
142 }
143
144
145
146
147 static const char * const pm_states[PM_SUSPEND_MAX] = {
148         [PM_SUSPEND_STANDBY]    = "standby",
149         [PM_SUSPEND_MEM]        = "mem",
150 #ifdef CONFIG_SOFTWARE_SUSPEND
151         [PM_SUSPEND_DISK]       = "disk",
152 #endif
153 };
154
155 static inline int valid_state(suspend_state_t state)
156 {
157         /* Suspend-to-disk does not really need low-level support.
158          * It can work with reboot if needed. */
159         if (state == PM_SUSPEND_DISK)
160                 return 1;
161
162         if (pm_ops && pm_ops->valid && !pm_ops->valid(state))
163                 return 0;
164         return 1;
165 }
166
167
168 /**
169  *      enter_state - Do common work of entering low-power state.
170  *      @state:         pm_state structure for state we're entering.
171  *
172  *      Make sure we're the only ones trying to enter a sleep state. Fail
173  *      if someone has beat us to it, since we don't want anything weird to
174  *      happen when we wake up.
175  *      Then, do the setup for suspend, enter the state, and cleaup (after
176  *      we've woken up).
177  */
178
179 static int enter_state(suspend_state_t state)
180 {
181         int error;
182
183         if (!valid_state(state))
184                 return -ENODEV;
185         if (down_trylock(&pm_sem))
186                 return -EBUSY;
187
188         if (state == PM_SUSPEND_DISK) {
189                 error = pm_suspend_disk();
190                 goto Unlock;
191         }
192
193         pr_debug("PM: Preparing system for %s sleep\n", pm_states[state]);
194         if ((error = suspend_prepare(state)))
195                 goto Unlock;
196
197         pr_debug("PM: Entering %s sleep\n", pm_states[state]);
198         error = suspend_enter(state);
199
200         pr_debug("PM: Finishing wakeup.\n");
201         suspend_finish(state);
202  Unlock:
203         up(&pm_sem);
204         return error;
205 }
206
207 /*
208  * This is main interface to the outside world. It needs to be
209  * called from process context.
210  */
211 int software_suspend(void)
212 {
213         return enter_state(PM_SUSPEND_DISK);
214 }
215
216
217 /**
218  *      pm_suspend - Externally visible function for suspending system.
219  *      @state:         Enumarted value of state to enter.
220  *
221  *      Determine whether or not value is within range, get state 
222  *      structure, and enter (above).
223  */
224
225 int pm_suspend(suspend_state_t state)
226 {
227         if (state > PM_SUSPEND_ON && state <= PM_SUSPEND_MAX)
228                 return enter_state(state);
229         return -EINVAL;
230 }
231
232
233
234 decl_subsys(power,NULL,NULL);
235
236
237 /**
238  *      state - control system power state.
239  *
240  *      show() returns what states are supported, which is hard-coded to
241  *      'standby' (Power-On Suspend), 'mem' (Suspend-to-RAM), and
242  *      'disk' (Suspend-to-Disk).
243  *
244  *      store() accepts one of those strings, translates it into the 
245  *      proper enumerated value, and initiates a suspend transition.
246  */
247
248 static ssize_t state_show(struct subsystem * subsys, char * buf)
249 {
250         int i;
251         char * s = buf;
252
253         for (i = 0; i < PM_SUSPEND_MAX; i++) {
254                 if (pm_states[i] && valid_state(i))
255                         s += sprintf(s,"%s ", pm_states[i]);
256         }
257         s += sprintf(s,"\n");
258         return (s - buf);
259 }
260
261 static ssize_t state_store(struct subsystem * subsys, const char * buf, size_t n)
262 {
263         suspend_state_t state = PM_SUSPEND_STANDBY;
264         const char * const *s;
265         char *p;
266         int error;
267         int len;
268
269         p = memchr(buf, '\n', n);
270         len = p ? p - buf : n;
271
272         for (s = &pm_states[state]; state < PM_SUSPEND_MAX; s++, state++) {
273                 if (*s && !strncmp(buf, *s, len))
274                         break;
275         }
276         if (state < PM_SUSPEND_MAX && *s)
277                 error = enter_state(state);
278         else
279                 error = -EINVAL;
280         return error ? error : n;
281 }
282
283 power_attr(state);
284
285 #ifdef CONFIG_PM_TRACE
286 int pm_trace_enabled;
287
288 static ssize_t pm_trace_show(struct subsystem * subsys, char * buf)
289 {
290         return sprintf(buf, "%d\n", pm_trace_enabled);
291 }
292
293 static ssize_t
294 pm_trace_store(struct subsystem * subsys, const char * buf, size_t n)
295 {
296         int val;
297
298         if (sscanf(buf, "%d", &val) == 1) {
299                 pm_trace_enabled = !!val;
300                 return n;
301         }
302         return -EINVAL;
303 }
304
305 power_attr(pm_trace);
306
307 static struct attribute * g[] = {
308         &state_attr.attr,
309         &pm_trace_attr.attr,
310         NULL,
311 };
312 #else
313 static struct attribute * g[] = {
314         &state_attr.attr,
315         NULL,
316 };
317 #endif /* CONFIG_PM_TRACE */
318
319 static struct attribute_group attr_group = {
320         .attrs = g,
321 };
322
323
324 static int __init pm_init(void)
325 {
326         int error = subsystem_register(&power_subsys);
327         if (!error)
328                 error = sysfs_create_group(&power_subsys.kset.kobj,&attr_group);
329         return error;
330 }
331
332 core_initcall(pm_init);