driver core: make /sys/power a kobject
[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/console.h>
19 #include <linux/cpu.h>
20 #include <linux/resume-trace.h>
21 #include <linux/freezer.h>
22 #include <linux/vmstat.h>
23 #include <linux/syscalls.h>
24
25 #include "power.h"
26
27 BLOCKING_NOTIFIER_HEAD(pm_chain_head);
28
29 DEFINE_MUTEX(pm_mutex);
30
31 unsigned int pm_flags;
32 EXPORT_SYMBOL(pm_flags);
33
34 #ifdef CONFIG_SUSPEND
35
36 /* This is just an arbitrary number */
37 #define FREE_PAGE_NUMBER (100)
38
39 static struct platform_suspend_ops *suspend_ops;
40
41 /**
42  *      suspend_set_ops - Set the global suspend method table.
43  *      @ops:   Pointer to ops structure.
44  */
45
46 void suspend_set_ops(struct platform_suspend_ops *ops)
47 {
48         mutex_lock(&pm_mutex);
49         suspend_ops = ops;
50         mutex_unlock(&pm_mutex);
51 }
52
53 /**
54  * suspend_valid_only_mem - generic memory-only valid callback
55  *
56  * Platform drivers that implement mem suspend only and only need
57  * to check for that in their .valid callback can use this instead
58  * of rolling their own .valid callback.
59  */
60 int suspend_valid_only_mem(suspend_state_t state)
61 {
62         return state == PM_SUSPEND_MEM;
63 }
64
65 /**
66  *      suspend_prepare - Do prep work before entering low-power state.
67  *
68  *      This is common code that is called for each state that we're entering.
69  *      Run suspend notifiers, allocate a console and stop all processes.
70  */
71 static int suspend_prepare(void)
72 {
73         int error;
74         unsigned int free_pages;
75
76         if (!suspend_ops || !suspend_ops->enter)
77                 return -EPERM;
78
79         error = pm_notifier_call_chain(PM_SUSPEND_PREPARE);
80         if (error)
81                 goto Finish;
82
83         pm_prepare_console();
84
85         if (freeze_processes()) {
86                 error = -EAGAIN;
87                 goto Thaw;
88         }
89
90         free_pages = global_page_state(NR_FREE_PAGES);
91         if (free_pages < FREE_PAGE_NUMBER) {
92                 pr_debug("PM: free some memory\n");
93                 shrink_all_memory(FREE_PAGE_NUMBER - free_pages);
94                 if (nr_free_pages() < FREE_PAGE_NUMBER) {
95                         error = -ENOMEM;
96                         printk(KERN_ERR "PM: No enough memory\n");
97                 }
98         }
99         if (!error)
100                 return 0;
101
102  Thaw:
103         thaw_processes();
104         pm_restore_console();
105  Finish:
106         pm_notifier_call_chain(PM_POST_SUSPEND);
107         return error;
108 }
109
110 /* default implementation */
111 void __attribute__ ((weak)) arch_suspend_disable_irqs(void)
112 {
113         local_irq_disable();
114 }
115
116 /* default implementation */
117 void __attribute__ ((weak)) arch_suspend_enable_irqs(void)
118 {
119         local_irq_enable();
120 }
121
122 /**
123  *      suspend_enter - enter the desired system sleep state.
124  *      @state:         state to enter
125  *
126  *      This function should be called after devices have been suspended.
127  */
128 static int suspend_enter(suspend_state_t state)
129 {
130         int error = 0;
131
132         arch_suspend_disable_irqs();
133         BUG_ON(!irqs_disabled());
134
135         if ((error = device_power_down(PMSG_SUSPEND))) {
136                 printk(KERN_ERR "Some devices failed to power down\n");
137                 goto Done;
138         }
139         error = suspend_ops->enter(state);
140         device_power_up();
141  Done:
142         arch_suspend_enable_irqs();
143         BUG_ON(irqs_disabled());
144         return error;
145 }
146
147 /**
148  *      suspend_devices_and_enter - suspend devices and enter the desired system sleep
149  *                        state.
150  *      @state:           state to enter
151  */
152 int suspend_devices_and_enter(suspend_state_t state)
153 {
154         int error;
155
156         if (!suspend_ops)
157                 return -ENOSYS;
158
159         if (suspend_ops->set_target) {
160                 error = suspend_ops->set_target(state);
161                 if (error)
162                         return error;
163         }
164         suspend_console();
165         error = device_suspend(PMSG_SUSPEND);
166         if (error) {
167                 printk(KERN_ERR "Some devices failed to suspend\n");
168                 goto Resume_console;
169         }
170         if (suspend_ops->prepare) {
171                 error = suspend_ops->prepare();
172                 if (error)
173                         goto Resume_devices;
174         }
175         error = disable_nonboot_cpus();
176         if (!error)
177                 suspend_enter(state);
178
179         enable_nonboot_cpus();
180         if (suspend_ops->finish)
181                 suspend_ops->finish();
182  Resume_devices:
183         device_resume();
184  Resume_console:
185         resume_console();
186         return error;
187 }
188
189 /**
190  *      suspend_finish - Do final work before exiting suspend sequence.
191  *
192  *      Call platform code to clean up, restart processes, and free the 
193  *      console that we've allocated. This is not called for suspend-to-disk.
194  */
195 static void suspend_finish(void)
196 {
197         thaw_processes();
198         pm_restore_console();
199         pm_notifier_call_chain(PM_POST_SUSPEND);
200 }
201
202
203
204
205 static const char * const pm_states[PM_SUSPEND_MAX] = {
206         [PM_SUSPEND_STANDBY]    = "standby",
207         [PM_SUSPEND_MEM]        = "mem",
208 };
209
210 static inline int valid_state(suspend_state_t state)
211 {
212         /* All states need lowlevel support and need to be valid
213          * to the lowlevel implementation, no valid callback
214          * implies that none are valid. */
215         if (!suspend_ops || !suspend_ops->valid || !suspend_ops->valid(state))
216                 return 0;
217         return 1;
218 }
219
220
221 /**
222  *      enter_state - Do common work of entering low-power state.
223  *      @state:         pm_state structure for state we're entering.
224  *
225  *      Make sure we're the only ones trying to enter a sleep state. Fail
226  *      if someone has beat us to it, since we don't want anything weird to
227  *      happen when we wake up.
228  *      Then, do the setup for suspend, enter the state, and cleaup (after
229  *      we've woken up).
230  */
231 static int enter_state(suspend_state_t state)
232 {
233         int error;
234
235         if (!valid_state(state))
236                 return -ENODEV;
237
238         if (!mutex_trylock(&pm_mutex))
239                 return -EBUSY;
240
241         printk("Syncing filesystems ... ");
242         sys_sync();
243         printk("done.\n");
244
245         pr_debug("PM: Preparing system for %s sleep\n", pm_states[state]);
246         if ((error = suspend_prepare()))
247                 goto Unlock;
248
249         pr_debug("PM: Entering %s sleep\n", pm_states[state]);
250         error = suspend_devices_and_enter(state);
251
252         pr_debug("PM: Finishing wakeup.\n");
253         suspend_finish();
254  Unlock:
255         mutex_unlock(&pm_mutex);
256         return error;
257 }
258
259
260 /**
261  *      pm_suspend - Externally visible function for suspending system.
262  *      @state:         Enumerated value of state to enter.
263  *
264  *      Determine whether or not value is within range, get state 
265  *      structure, and enter (above).
266  */
267
268 int pm_suspend(suspend_state_t state)
269 {
270         if (state > PM_SUSPEND_ON && state <= PM_SUSPEND_MAX)
271                 return enter_state(state);
272         return -EINVAL;
273 }
274
275 EXPORT_SYMBOL(pm_suspend);
276
277 #endif /* CONFIG_SUSPEND */
278
279 struct kobject *power_kobj;
280
281 /**
282  *      state - control system power state.
283  *
284  *      show() returns what states are supported, which is hard-coded to
285  *      'standby' (Power-On Suspend), 'mem' (Suspend-to-RAM), and
286  *      'disk' (Suspend-to-Disk).
287  *
288  *      store() accepts one of those strings, translates it into the 
289  *      proper enumerated value, and initiates a suspend transition.
290  */
291
292 static ssize_t state_show(struct kobject *kobj, struct kobj_attribute *attr,
293                           char *buf)
294 {
295         char *s = buf;
296 #ifdef CONFIG_SUSPEND
297         int i;
298
299         for (i = 0; i < PM_SUSPEND_MAX; i++) {
300                 if (pm_states[i] && valid_state(i))
301                         s += sprintf(s,"%s ", pm_states[i]);
302         }
303 #endif
304 #ifdef CONFIG_HIBERNATION
305         s += sprintf(s, "%s\n", "disk");
306 #else
307         if (s != buf)
308                 /* convert the last space to a newline */
309                 *(s-1) = '\n';
310 #endif
311         return (s - buf);
312 }
313
314 static ssize_t state_store(struct kobject *kobj, struct kobj_attribute *attr,
315                            const char *buf, size_t n)
316 {
317 #ifdef CONFIG_SUSPEND
318         suspend_state_t state = PM_SUSPEND_STANDBY;
319         const char * const *s;
320 #endif
321         char *p;
322         int len;
323         int error = -EINVAL;
324
325         p = memchr(buf, '\n', n);
326         len = p ? p - buf : n;
327
328         /* First, check if we are requested to hibernate */
329         if (len == 4 && !strncmp(buf, "disk", len)) {
330                 error = hibernate();
331   goto Exit;
332         }
333
334 #ifdef CONFIG_SUSPEND
335         for (s = &pm_states[state]; state < PM_SUSPEND_MAX; s++, state++) {
336                 if (*s && len == strlen(*s) && !strncmp(buf, *s, len))
337                         break;
338         }
339         if (state < PM_SUSPEND_MAX && *s)
340                 error = enter_state(state);
341 #endif
342
343  Exit:
344         return error ? error : n;
345 }
346
347 power_attr(state);
348
349 #ifdef CONFIG_PM_TRACE
350 int pm_trace_enabled;
351
352 static ssize_t pm_trace_show(struct kobject *kobj, struct kobj_attribute *attr,
353                              char *buf)
354 {
355         return sprintf(buf, "%d\n", pm_trace_enabled);
356 }
357
358 static ssize_t
359 pm_trace_store(struct kobject *kobj, struct kobj_attribute *attr,
360                const char *buf, size_t n)
361 {
362         int val;
363
364         if (sscanf(buf, "%d", &val) == 1) {
365                 pm_trace_enabled = !!val;
366                 return n;
367         }
368         return -EINVAL;
369 }
370
371 power_attr(pm_trace);
372
373 static struct attribute * g[] = {
374         &state_attr.attr,
375         &pm_trace_attr.attr,
376         NULL,
377 };
378 #else
379 static struct attribute * g[] = {
380         &state_attr.attr,
381         NULL,
382 };
383 #endif /* CONFIG_PM_TRACE */
384
385 static struct attribute_group attr_group = {
386         .attrs = g,
387 };
388
389
390 static int __init pm_init(void)
391 {
392         power_kobj = kobject_create_and_add("power", NULL);
393         if (!power_kobj)
394                 return -ENOMEM;
395         return sysfs_create_group(power_kobj, &attr_group);
396 }
397
398 core_initcall(pm_init);