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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 | ||
5a72e04d LS |
58 | disable_nonboot_cpus(); |
59 | ||
60 | if (num_online_cpus() != 1) { | |
61 | error = -EPERM; | |
62 | goto Enable_cpu; | |
63 | } | |
64 | ||
1da177e4 LT |
65 | if (freeze_processes()) { |
66 | error = -EAGAIN; | |
67 | goto Thaw; | |
68 | } | |
69 | ||
70 | if (pm_ops->prepare) { | |
71 | if ((error = pm_ops->prepare(state))) | |
72 | goto Thaw; | |
73 | } | |
74 | ||
75 | if ((error = device_suspend(PMSG_SUSPEND))) { | |
76 | printk(KERN_ERR "Some devices failed to suspend\n"); | |
77 | goto Finish; | |
78 | } | |
79 | return 0; | |
80 | Finish: | |
81 | if (pm_ops->finish) | |
82 | pm_ops->finish(state); | |
83 | Thaw: | |
84 | thaw_processes(); | |
5a72e04d LS |
85 | Enable_cpu: |
86 | enable_nonboot_cpus(); | |
1da177e4 LT |
87 | pm_restore_console(); |
88 | return error; | |
89 | } | |
90 | ||
91 | ||
92 | static int suspend_enter(suspend_state_t state) | |
93 | { | |
94 | int error = 0; | |
95 | unsigned long flags; | |
96 | ||
97 | local_irq_save(flags); | |
98 | ||
99 | if ((error = device_power_down(PMSG_SUSPEND))) { | |
100 | printk(KERN_ERR "Some devices failed to power down\n"); | |
101 | goto Done; | |
102 | } | |
103 | error = pm_ops->enter(state); | |
104 | device_power_up(); | |
105 | Done: | |
106 | local_irq_restore(flags); | |
107 | return error; | |
108 | } | |
109 | ||
110 | ||
111 | /** | |
112 | * suspend_finish - Do final work before exiting suspend sequence. | |
113 | * @state: State we're coming out of. | |
114 | * | |
115 | * Call platform code to clean up, restart processes, and free the | |
116 | * console that we've allocated. This is not called for suspend-to-disk. | |
117 | */ | |
118 | ||
119 | static void suspend_finish(suspend_state_t state) | |
120 | { | |
121 | device_resume(); | |
122 | if (pm_ops && pm_ops->finish) | |
123 | pm_ops->finish(state); | |
124 | thaw_processes(); | |
5a72e04d | 125 | enable_nonboot_cpus(); |
1da177e4 LT |
126 | pm_restore_console(); |
127 | } | |
128 | ||
129 | ||
130 | ||
131 | ||
132 | static char * pm_states[] = { | |
133 | [PM_SUSPEND_STANDBY] = "standby", | |
134 | [PM_SUSPEND_MEM] = "mem", | |
135 | [PM_SUSPEND_DISK] = "disk", | |
136 | NULL, | |
137 | }; | |
138 | ||
139 | ||
140 | /** | |
141 | * enter_state - Do common work of entering low-power state. | |
142 | * @state: pm_state structure for state we're entering. | |
143 | * | |
144 | * Make sure we're the only ones trying to enter a sleep state. Fail | |
145 | * if someone has beat us to it, since we don't want anything weird to | |
146 | * happen when we wake up. | |
147 | * Then, do the setup for suspend, enter the state, and cleaup (after | |
148 | * we've woken up). | |
149 | */ | |
150 | ||
151 | static int enter_state(suspend_state_t state) | |
152 | { | |
153 | int error; | |
154 | ||
155 | if (down_trylock(&pm_sem)) | |
156 | return -EBUSY; | |
157 | ||
158 | if (state == PM_SUSPEND_DISK) { | |
159 | error = pm_suspend_disk(); | |
160 | goto Unlock; | |
161 | } | |
162 | ||
82428b62 | 163 | pr_debug("PM: Preparing system for %s sleep\n", pm_states[state]); |
1da177e4 LT |
164 | if ((error = suspend_prepare(state))) |
165 | goto Unlock; | |
166 | ||
82428b62 | 167 | pr_debug("PM: Entering %s sleep\n", pm_states[state]); |
1da177e4 LT |
168 | error = suspend_enter(state); |
169 | ||
82428b62 | 170 | pr_debug("PM: Finishing wakeup.\n"); |
1da177e4 LT |
171 | suspend_finish(state); |
172 | Unlock: | |
173 | up(&pm_sem); | |
174 | return error; | |
175 | } | |
176 | ||
177 | /* | |
178 | * This is main interface to the outside world. It needs to be | |
179 | * called from process context. | |
180 | */ | |
181 | int software_suspend(void) | |
182 | { | |
183 | return enter_state(PM_SUSPEND_DISK); | |
184 | } | |
185 | ||
186 | ||
187 | /** | |
188 | * pm_suspend - Externally visible function for suspending system. | |
189 | * @state: Enumarted value of state to enter. | |
190 | * | |
191 | * Determine whether or not value is within range, get state | |
192 | * structure, and enter (above). | |
193 | */ | |
194 | ||
195 | int pm_suspend(suspend_state_t state) | |
196 | { | |
197 | if (state > PM_SUSPEND_ON && state < PM_SUSPEND_MAX) | |
198 | return enter_state(state); | |
199 | return -EINVAL; | |
200 | } | |
201 | ||
202 | ||
203 | ||
204 | decl_subsys(power,NULL,NULL); | |
205 | ||
206 | ||
207 | /** | |
208 | * state - control system power state. | |
209 | * | |
210 | * show() returns what states are supported, which is hard-coded to | |
211 | * 'standby' (Power-On Suspend), 'mem' (Suspend-to-RAM), and | |
212 | * 'disk' (Suspend-to-Disk). | |
213 | * | |
214 | * store() accepts one of those strings, translates it into the | |
215 | * proper enumerated value, and initiates a suspend transition. | |
216 | */ | |
217 | ||
218 | static ssize_t state_show(struct subsystem * subsys, char * buf) | |
219 | { | |
220 | int i; | |
221 | char * s = buf; | |
222 | ||
223 | for (i = 0; i < PM_SUSPEND_MAX; i++) { | |
224 | if (pm_states[i]) | |
225 | s += sprintf(s,"%s ",pm_states[i]); | |
226 | } | |
227 | s += sprintf(s,"\n"); | |
228 | return (s - buf); | |
229 | } | |
230 | ||
231 | static ssize_t state_store(struct subsystem * subsys, const char * buf, size_t n) | |
232 | { | |
233 | suspend_state_t state = PM_SUSPEND_STANDBY; | |
234 | char ** s; | |
235 | char *p; | |
236 | int error; | |
237 | int len; | |
238 | ||
239 | p = memchr(buf, '\n', n); | |
240 | len = p ? p - buf : n; | |
241 | ||
242 | for (s = &pm_states[state]; state < PM_SUSPEND_MAX; s++, state++) { | |
243 | if (*s && !strncmp(buf, *s, len)) | |
244 | break; | |
245 | } | |
246 | if (*s) | |
247 | error = enter_state(state); | |
248 | else | |
249 | error = -EINVAL; | |
250 | return error ? error : n; | |
251 | } | |
252 | ||
253 | power_attr(state); | |
254 | ||
255 | static struct attribute * g[] = { | |
256 | &state_attr.attr, | |
257 | NULL, | |
258 | }; | |
259 | ||
260 | static struct attribute_group attr_group = { | |
261 | .attrs = g, | |
262 | }; | |
263 | ||
264 | ||
265 | static int __init pm_init(void) | |
266 | { | |
267 | int error = subsystem_register(&power_subsys); | |
268 | if (!error) | |
269 | error = sysfs_create_group(&power_subsys.kset.kobj,&attr_group); | |
270 | return error; | |
271 | } | |
272 | ||
273 | core_initcall(pm_init); |