power management: no valid states w/o pm_ops
[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/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 suspend_disk_method_t pm_disk_mode = PM_DISK_PLATFORM;
34
35 /**
36  *      pm_set_ops - Set the global power method table. 
37  *      @ops:   Pointer to ops structure.
38  */
39
40 void pm_set_ops(struct pm_ops * ops)
41 {
42         mutex_lock(&pm_mutex);
43         pm_ops = ops;
44         mutex_unlock(&pm_mutex);
45 }
46
47 static inline void pm_finish(suspend_state_t state)
48 {
49         if (pm_ops->finish)
50                 pm_ops->finish(state);
51 }
52
53 /**
54  *      suspend_prepare - Do prep work before entering low-power state.
55  *      @state:         State we're entering.
56  *
57  *      This is common code that is called for each state that we're 
58  *      entering. Allocate a console, stop all processes, then make sure
59  *      the platform can enter the requested state.
60  */
61
62 static int suspend_prepare(suspend_state_t state)
63 {
64         int error;
65         unsigned int free_pages;
66
67         if (!pm_ops || !pm_ops->enter)
68                 return -EPERM;
69
70         pm_prepare_console();
71
72         if (freeze_processes()) {
73                 error = -EAGAIN;
74                 goto Thaw;
75         }
76
77         if ((free_pages = global_page_state(NR_FREE_PAGES))
78                         < FREE_PAGE_NUMBER) {
79                 pr_debug("PM: free some memory\n");
80                 shrink_all_memory(FREE_PAGE_NUMBER - free_pages);
81                 if (nr_free_pages() < FREE_PAGE_NUMBER) {
82                         error = -ENOMEM;
83                         printk(KERN_ERR "PM: No enough memory\n");
84                         goto Thaw;
85                 }
86         }
87
88         if (pm_ops->prepare) {
89                 if ((error = pm_ops->prepare(state)))
90                         goto Thaw;
91         }
92
93         suspend_console();
94         error = device_suspend(PMSG_SUSPEND);
95         if (error) {
96                 printk(KERN_ERR "Some devices failed to suspend\n");
97                 goto Resume_devices;
98         }
99         error = disable_nonboot_cpus();
100         if (!error)
101                 return 0;
102
103         enable_nonboot_cpus();
104  Resume_devices:
105         pm_finish(state);
106         device_resume();
107         resume_console();
108  Thaw:
109         thaw_processes();
110         pm_restore_console();
111         return error;
112 }
113
114
115 int suspend_enter(suspend_state_t state)
116 {
117         int error = 0;
118         unsigned long flags;
119
120         local_irq_save(flags);
121
122         if ((error = device_power_down(PMSG_SUSPEND))) {
123                 printk(KERN_ERR "Some devices failed to power down\n");
124                 goto Done;
125         }
126         error = pm_ops->enter(state);
127         device_power_up();
128  Done:
129         local_irq_restore(flags);
130         return error;
131 }
132
133
134 /**
135  *      suspend_finish - Do final work before exiting suspend sequence.
136  *      @state:         State we're coming out of.
137  *
138  *      Call platform code to clean up, restart processes, and free the 
139  *      console that we've allocated. This is not called for suspend-to-disk.
140  */
141
142 static void suspend_finish(suspend_state_t state)
143 {
144         enable_nonboot_cpus();
145         pm_finish(state);
146         device_resume();
147         resume_console();
148         thaw_processes();
149         pm_restore_console();
150 }
151
152
153
154
155 static const char * const pm_states[PM_SUSPEND_MAX] = {
156         [PM_SUSPEND_STANDBY]    = "standby",
157         [PM_SUSPEND_MEM]        = "mem",
158 #ifdef CONFIG_SOFTWARE_SUSPEND
159         [PM_SUSPEND_DISK]       = "disk",
160 #endif
161 };
162
163 static inline int valid_state(suspend_state_t state)
164 {
165         /* Suspend-to-disk does not really need low-level support.
166          * It can work with reboot if needed. */
167         if (state == PM_SUSPEND_DISK)
168                 return 1;
169
170         /* all other states need lowlevel support and need to be
171          * valid to the lowlevel implementation, no valid callback
172          * implies that all are valid. */
173         if (!pm_ops || (pm_ops->valid && !pm_ops->valid(state)))
174                 return 0;
175         return 1;
176 }
177
178
179 /**
180  *      enter_state - Do common work of entering low-power state.
181  *      @state:         pm_state structure for state we're entering.
182  *
183  *      Make sure we're the only ones trying to enter a sleep state. Fail
184  *      if someone has beat us to it, since we don't want anything weird to
185  *      happen when we wake up.
186  *      Then, do the setup for suspend, enter the state, and cleaup (after
187  *      we've woken up).
188  */
189
190 static int enter_state(suspend_state_t state)
191 {
192         int error;
193
194         if (!valid_state(state))
195                 return -ENODEV;
196         if (!mutex_trylock(&pm_mutex))
197                 return -EBUSY;
198
199         if (state == PM_SUSPEND_DISK) {
200                 error = pm_suspend_disk();
201                 goto Unlock;
202         }
203
204         pr_debug("PM: Preparing system for %s sleep\n", pm_states[state]);
205         if ((error = suspend_prepare(state)))
206                 goto Unlock;
207
208         pr_debug("PM: Entering %s sleep\n", pm_states[state]);
209         error = suspend_enter(state);
210
211         pr_debug("PM: Finishing wakeup.\n");
212         suspend_finish(state);
213  Unlock:
214         mutex_unlock(&pm_mutex);
215         return error;
216 }
217
218 /*
219  * This is main interface to the outside world. It needs to be
220  * called from process context.
221  */
222 int software_suspend(void)
223 {
224         return enter_state(PM_SUSPEND_DISK);
225 }
226
227
228 /**
229  *      pm_suspend - Externally visible function for suspending system.
230  *      @state:         Enumarted value of state to enter.
231  *
232  *      Determine whether or not value is within range, get state 
233  *      structure, and enter (above).
234  */
235
236 int pm_suspend(suspend_state_t state)
237 {
238         if (state > PM_SUSPEND_ON && state <= PM_SUSPEND_MAX)
239                 return enter_state(state);
240         return -EINVAL;
241 }
242
243 EXPORT_SYMBOL(pm_suspend);
244
245 decl_subsys(power,NULL,NULL);
246
247
248 /**
249  *      state - control system power state.
250  *
251  *      show() returns what states are supported, which is hard-coded to
252  *      'standby' (Power-On Suspend), 'mem' (Suspend-to-RAM), and
253  *      'disk' (Suspend-to-Disk).
254  *
255  *      store() accepts one of those strings, translates it into the 
256  *      proper enumerated value, and initiates a suspend transition.
257  */
258
259 static ssize_t state_show(struct subsystem * subsys, char * buf)
260 {
261         int i;
262         char * s = buf;
263
264         for (i = 0; i < PM_SUSPEND_MAX; i++) {
265                 if (pm_states[i] && valid_state(i))
266                         s += sprintf(s,"%s ", pm_states[i]);
267         }
268         s += sprintf(s,"\n");
269         return (s - buf);
270 }
271
272 static ssize_t state_store(struct subsystem * subsys, const char * buf, size_t n)
273 {
274         suspend_state_t state = PM_SUSPEND_STANDBY;
275         const char * const *s;
276         char *p;
277         int error;
278         int len;
279
280         p = memchr(buf, '\n', n);
281         len = p ? p - buf : n;
282
283         for (s = &pm_states[state]; state < PM_SUSPEND_MAX; s++, state++) {
284                 if (*s && !strncmp(buf, *s, len))
285                         break;
286         }
287         if (state < PM_SUSPEND_MAX && *s)
288                 error = enter_state(state);
289         else
290                 error = -EINVAL;
291         return error ? error : n;
292 }
293
294 power_attr(state);
295
296 #ifdef CONFIG_PM_TRACE
297 int pm_trace_enabled;
298
299 static ssize_t pm_trace_show(struct subsystem * subsys, char * buf)
300 {
301         return sprintf(buf, "%d\n", pm_trace_enabled);
302 }
303
304 static ssize_t
305 pm_trace_store(struct subsystem * subsys, const char * buf, size_t n)
306 {
307         int val;
308
309         if (sscanf(buf, "%d", &val) == 1) {
310                 pm_trace_enabled = !!val;
311                 return n;
312         }
313         return -EINVAL;
314 }
315
316 power_attr(pm_trace);
317
318 static struct attribute * g[] = {
319         &state_attr.attr,
320         &pm_trace_attr.attr,
321         NULL,
322 };
323 #else
324 static struct attribute * g[] = {
325         &state_attr.attr,
326         NULL,
327 };
328 #endif /* CONFIG_PM_TRACE */
329
330 static struct attribute_group attr_group = {
331         .attrs = g,
332 };
333
334
335 static int __init pm_init(void)
336 {
337         int error = subsystem_register(&power_subsys);
338         if (!error)
339                 error = sysfs_create_group(&power_subsys.kset.kobj,&attr_group);
340         return error;
341 }
342
343 core_initcall(pm_init);