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1da177e4 LT |
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 | DECLARE_MUTEX(pm_sem); | |
23 | ||
24 | struct pm_ops * pm_ops = NULL; | |
25 | suspend_disk_method_t pm_disk_mode = PM_DISK_SHUTDOWN; | |
26 | ||
27 | /** | |
28 | * pm_set_ops - Set the global power method table. | |
29 | * @ops: Pointer to ops structure. | |
30 | */ | |
31 | ||
32 | void pm_set_ops(struct pm_ops * ops) | |
33 | { | |
34 | down(&pm_sem); | |
35 | pm_ops = ops; | |
36 | up(&pm_sem); | |
37 | } | |
38 | ||
39 | ||
40 | /** | |
41 | * suspend_prepare - Do prep work before entering low-power state. | |
42 | * @state: State we're entering. | |
43 | * | |
44 | * This is common code that is called for each state that we're | |
45 | * entering. Allocate a console, stop all processes, then make sure | |
46 | * the platform can enter the requested state. | |
47 | */ | |
48 | ||
49 | static int suspend_prepare(suspend_state_t state) | |
50 | { | |
51 | int error = 0; | |
52 | ||
53 | if (!pm_ops || !pm_ops->enter) | |
54 | return -EPERM; | |
55 | ||
56 | pm_prepare_console(); | |
57 | ||
58 | if (freeze_processes()) { | |
59 | error = -EAGAIN; | |
60 | goto Thaw; | |
61 | } | |
62 | ||
63 | if (pm_ops->prepare) { | |
64 | if ((error = pm_ops->prepare(state))) | |
65 | goto Thaw; | |
66 | } | |
67 | ||
68 | if ((error = device_suspend(PMSG_SUSPEND))) { | |
69 | printk(KERN_ERR "Some devices failed to suspend\n"); | |
70 | goto Finish; | |
71 | } | |
72 | return 0; | |
73 | Finish: | |
74 | if (pm_ops->finish) | |
75 | pm_ops->finish(state); | |
76 | Thaw: | |
77 | thaw_processes(); | |
78 | pm_restore_console(); | |
79 | return error; | |
80 | } | |
81 | ||
82 | ||
83 | static int suspend_enter(suspend_state_t state) | |
84 | { | |
85 | int error = 0; | |
86 | unsigned long flags; | |
87 | ||
88 | local_irq_save(flags); | |
89 | ||
90 | if ((error = device_power_down(PMSG_SUSPEND))) { | |
91 | printk(KERN_ERR "Some devices failed to power down\n"); | |
92 | goto Done; | |
93 | } | |
94 | error = pm_ops->enter(state); | |
95 | device_power_up(); | |
96 | Done: | |
97 | local_irq_restore(flags); | |
98 | return error; | |
99 | } | |
100 | ||
101 | ||
102 | /** | |
103 | * suspend_finish - Do final work before exiting suspend sequence. | |
104 | * @state: State we're coming out of. | |
105 | * | |
106 | * Call platform code to clean up, restart processes, and free the | |
107 | * console that we've allocated. This is not called for suspend-to-disk. | |
108 | */ | |
109 | ||
110 | static void suspend_finish(suspend_state_t state) | |
111 | { | |
112 | device_resume(); | |
113 | if (pm_ops && pm_ops->finish) | |
114 | pm_ops->finish(state); | |
115 | thaw_processes(); | |
116 | pm_restore_console(); | |
117 | } | |
118 | ||
119 | ||
120 | ||
121 | ||
122 | static char * pm_states[] = { | |
123 | [PM_SUSPEND_STANDBY] = "standby", | |
124 | [PM_SUSPEND_MEM] = "mem", | |
125 | [PM_SUSPEND_DISK] = "disk", | |
126 | NULL, | |
127 | }; | |
128 | ||
129 | ||
130 | /** | |
131 | * enter_state - Do common work of entering low-power state. | |
132 | * @state: pm_state structure for state we're entering. | |
133 | * | |
134 | * Make sure we're the only ones trying to enter a sleep state. Fail | |
135 | * if someone has beat us to it, since we don't want anything weird to | |
136 | * happen when we wake up. | |
137 | * Then, do the setup for suspend, enter the state, and cleaup (after | |
138 | * we've woken up). | |
139 | */ | |
140 | ||
141 | static int enter_state(suspend_state_t state) | |
142 | { | |
143 | int error; | |
144 | ||
145 | if (down_trylock(&pm_sem)) | |
146 | return -EBUSY; | |
147 | ||
148 | if (state == PM_SUSPEND_DISK) { | |
149 | error = pm_suspend_disk(); | |
150 | goto Unlock; | |
151 | } | |
152 | ||
153 | /* Suspend is hard to get right on SMP. */ | |
154 | if (num_online_cpus() != 1) { | |
155 | error = -EPERM; | |
156 | goto Unlock; | |
157 | } | |
158 | ||
82428b62 | 159 | pr_debug("PM: Preparing system for %s sleep\n", pm_states[state]); |
1da177e4 LT |
160 | if ((error = suspend_prepare(state))) |
161 | goto Unlock; | |
162 | ||
82428b62 | 163 | pr_debug("PM: Entering %s sleep\n", pm_states[state]); |
1da177e4 LT |
164 | error = suspend_enter(state); |
165 | ||
82428b62 | 166 | pr_debug("PM: Finishing wakeup.\n"); |
1da177e4 LT |
167 | suspend_finish(state); |
168 | Unlock: | |
169 | up(&pm_sem); | |
170 | return error; | |
171 | } | |
172 | ||
173 | /* | |
174 | * This is main interface to the outside world. It needs to be | |
175 | * called from process context. | |
176 | */ | |
177 | int software_suspend(void) | |
178 | { | |
179 | return enter_state(PM_SUSPEND_DISK); | |
180 | } | |
181 | ||
182 | ||
183 | /** | |
184 | * pm_suspend - Externally visible function for suspending system. | |
185 | * @state: Enumarted value of state to enter. | |
186 | * | |
187 | * Determine whether or not value is within range, get state | |
188 | * structure, and enter (above). | |
189 | */ | |
190 | ||
191 | int pm_suspend(suspend_state_t state) | |
192 | { | |
e2a5b420 | 193 | if (state > PM_SUSPEND_ON && state <= PM_SUSPEND_MAX) |
1da177e4 LT |
194 | return enter_state(state); |
195 | return -EINVAL; | |
196 | } | |
197 | ||
198 | ||
199 | ||
200 | decl_subsys(power,NULL,NULL); | |
201 | ||
202 | ||
203 | /** | |
204 | * state - control system power state. | |
205 | * | |
206 | * show() returns what states are supported, which is hard-coded to | |
207 | * 'standby' (Power-On Suspend), 'mem' (Suspend-to-RAM), and | |
208 | * 'disk' (Suspend-to-Disk). | |
209 | * | |
210 | * store() accepts one of those strings, translates it into the | |
211 | * proper enumerated value, and initiates a suspend transition. | |
212 | */ | |
213 | ||
214 | static ssize_t state_show(struct subsystem * subsys, char * buf) | |
215 | { | |
216 | int i; | |
217 | char * s = buf; | |
218 | ||
219 | for (i = 0; i < PM_SUSPEND_MAX; i++) { | |
220 | if (pm_states[i]) | |
221 | s += sprintf(s,"%s ",pm_states[i]); | |
222 | } | |
223 | s += sprintf(s,"\n"); | |
224 | return (s - buf); | |
225 | } | |
226 | ||
227 | static ssize_t state_store(struct subsystem * subsys, const char * buf, size_t n) | |
228 | { | |
229 | suspend_state_t state = PM_SUSPEND_STANDBY; | |
230 | char ** s; | |
231 | char *p; | |
232 | int error; | |
233 | int len; | |
234 | ||
235 | p = memchr(buf, '\n', n); | |
236 | len = p ? p - buf : n; | |
237 | ||
238 | for (s = &pm_states[state]; state < PM_SUSPEND_MAX; s++, state++) { | |
239 | if (*s && !strncmp(buf, *s, len)) | |
240 | break; | |
241 | } | |
242 | if (*s) | |
243 | error = enter_state(state); | |
244 | else | |
245 | error = -EINVAL; | |
246 | return error ? error : n; | |
247 | } | |
248 | ||
249 | power_attr(state); | |
250 | ||
251 | static struct attribute * g[] = { | |
252 | &state_attr.attr, | |
253 | NULL, | |
254 | }; | |
255 | ||
256 | static struct attribute_group attr_group = { | |
257 | .attrs = g, | |
258 | }; | |
259 | ||
260 | ||
261 | static int __init pm_init(void) | |
262 | { | |
263 | int error = subsystem_register(&power_subsys); | |
264 | if (!error) | |
265 | error = sysfs_create_group(&power_subsys.kset.kobj,&attr_group); | |
266 | return error; | |
267 | } | |
268 | ||
269 | core_initcall(pm_init); |