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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 | ||
5ae947ec DSL |
22 | /*This is just an arbitrary number */ |
23 | #define FREE_PAGE_NUMBER (100) | |
24 | ||
1da177e4 LT |
25 | DECLARE_MUTEX(pm_sem); |
26 | ||
27 | struct pm_ops * pm_ops = NULL; | |
28 | suspend_disk_method_t pm_disk_mode = PM_DISK_SHUTDOWN; | |
29 | ||
30 | /** | |
31 | * pm_set_ops - Set the global power method table. | |
32 | * @ops: Pointer to ops structure. | |
33 | */ | |
34 | ||
35 | void pm_set_ops(struct pm_ops * ops) | |
36 | { | |
37 | down(&pm_sem); | |
38 | pm_ops = ops; | |
39 | up(&pm_sem); | |
40 | } | |
41 | ||
42 | ||
43 | /** | |
44 | * suspend_prepare - Do prep work before entering low-power state. | |
45 | * @state: State we're entering. | |
46 | * | |
47 | * This is common code that is called for each state that we're | |
48 | * entering. Allocate a console, stop all processes, then make sure | |
49 | * the platform can enter the requested state. | |
50 | */ | |
51 | ||
52 | static int suspend_prepare(suspend_state_t state) | |
53 | { | |
54 | int error = 0; | |
5ae947ec | 55 | unsigned int free_pages; |
1da177e4 LT |
56 | |
57 | if (!pm_ops || !pm_ops->enter) | |
58 | return -EPERM; | |
59 | ||
60 | pm_prepare_console(); | |
61 | ||
5a72e04d LS |
62 | disable_nonboot_cpus(); |
63 | ||
64 | if (num_online_cpus() != 1) { | |
65 | error = -EPERM; | |
66 | goto Enable_cpu; | |
67 | } | |
68 | ||
1da177e4 LT |
69 | if (freeze_processes()) { |
70 | error = -EAGAIN; | |
71 | goto Thaw; | |
72 | } | |
73 | ||
5ae947ec DSL |
74 | if ((free_pages = nr_free_pages()) < FREE_PAGE_NUMBER) { |
75 | pr_debug("PM: free some memory\n"); | |
76 | shrink_all_memory(FREE_PAGE_NUMBER - free_pages); | |
77 | if (nr_free_pages() < FREE_PAGE_NUMBER) { | |
78 | error = -ENOMEM; | |
79 | printk(KERN_ERR "PM: No enough memory\n"); | |
80 | goto Thaw; | |
81 | } | |
82 | } | |
83 | ||
1da177e4 LT |
84 | if (pm_ops->prepare) { |
85 | if ((error = pm_ops->prepare(state))) | |
86 | goto Thaw; | |
87 | } | |
88 | ||
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(); | |
5a72e04d LS |
99 | Enable_cpu: |
100 | enable_nonboot_cpus(); | |
1da177e4 LT |
101 | pm_restore_console(); |
102 | return error; | |
103 | } | |
104 | ||
105 | ||
106 | static 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 | if (pm_ops && pm_ops->finish) | |
137 | pm_ops->finish(state); | |
138 | thaw_processes(); | |
5a72e04d | 139 | enable_nonboot_cpus(); |
1da177e4 LT |
140 | pm_restore_console(); |
141 | } | |
142 | ||
143 | ||
144 | ||
145 | ||
146 | static char * pm_states[] = { | |
147 | [PM_SUSPEND_STANDBY] = "standby", | |
148 | [PM_SUSPEND_MEM] = "mem", | |
149 | [PM_SUSPEND_DISK] = "disk", | |
150 | NULL, | |
151 | }; | |
152 | ||
153 | ||
154 | /** | |
155 | * enter_state - Do common work of entering low-power state. | |
156 | * @state: pm_state structure for state we're entering. | |
157 | * | |
158 | * Make sure we're the only ones trying to enter a sleep state. Fail | |
159 | * if someone has beat us to it, since we don't want anything weird to | |
160 | * happen when we wake up. | |
161 | * Then, do the setup for suspend, enter the state, and cleaup (after | |
162 | * we've woken up). | |
163 | */ | |
164 | ||
165 | static int enter_state(suspend_state_t state) | |
166 | { | |
167 | int error; | |
168 | ||
169 | if (down_trylock(&pm_sem)) | |
170 | return -EBUSY; | |
171 | ||
172 | if (state == PM_SUSPEND_DISK) { | |
173 | error = pm_suspend_disk(); | |
174 | goto Unlock; | |
175 | } | |
176 | ||
82428b62 | 177 | pr_debug("PM: Preparing system for %s sleep\n", pm_states[state]); |
1da177e4 LT |
178 | if ((error = suspend_prepare(state))) |
179 | goto Unlock; | |
180 | ||
82428b62 | 181 | pr_debug("PM: Entering %s sleep\n", pm_states[state]); |
1da177e4 LT |
182 | error = suspend_enter(state); |
183 | ||
82428b62 | 184 | pr_debug("PM: Finishing wakeup.\n"); |
1da177e4 LT |
185 | suspend_finish(state); |
186 | Unlock: | |
187 | up(&pm_sem); | |
188 | return error; | |
189 | } | |
190 | ||
191 | /* | |
192 | * This is main interface to the outside world. It needs to be | |
193 | * called from process context. | |
194 | */ | |
195 | int software_suspend(void) | |
196 | { | |
197 | return enter_state(PM_SUSPEND_DISK); | |
198 | } | |
199 | ||
200 | ||
201 | /** | |
202 | * pm_suspend - Externally visible function for suspending system. | |
203 | * @state: Enumarted value of state to enter. | |
204 | * | |
205 | * Determine whether or not value is within range, get state | |
206 | * structure, and enter (above). | |
207 | */ | |
208 | ||
209 | int pm_suspend(suspend_state_t state) | |
210 | { | |
e2a5b420 | 211 | if (state > PM_SUSPEND_ON && state <= PM_SUSPEND_MAX) |
1da177e4 LT |
212 | return enter_state(state); |
213 | return -EINVAL; | |
214 | } | |
215 | ||
216 | ||
217 | ||
218 | decl_subsys(power,NULL,NULL); | |
219 | ||
220 | ||
221 | /** | |
222 | * state - control system power state. | |
223 | * | |
224 | * show() returns what states are supported, which is hard-coded to | |
225 | * 'standby' (Power-On Suspend), 'mem' (Suspend-to-RAM), and | |
226 | * 'disk' (Suspend-to-Disk). | |
227 | * | |
228 | * store() accepts one of those strings, translates it into the | |
229 | * proper enumerated value, and initiates a suspend transition. | |
230 | */ | |
231 | ||
232 | static ssize_t state_show(struct subsystem * subsys, char * buf) | |
233 | { | |
234 | int i; | |
235 | char * s = buf; | |
236 | ||
237 | for (i = 0; i < PM_SUSPEND_MAX; i++) { | |
238 | if (pm_states[i]) | |
239 | s += sprintf(s,"%s ",pm_states[i]); | |
240 | } | |
241 | s += sprintf(s,"\n"); | |
242 | return (s - buf); | |
243 | } | |
244 | ||
245 | static ssize_t state_store(struct subsystem * subsys, const char * buf, size_t n) | |
246 | { | |
247 | suspend_state_t state = PM_SUSPEND_STANDBY; | |
248 | char ** s; | |
249 | char *p; | |
250 | int error; | |
251 | int len; | |
252 | ||
253 | p = memchr(buf, '\n', n); | |
254 | len = p ? p - buf : n; | |
255 | ||
256 | for (s = &pm_states[state]; state < PM_SUSPEND_MAX; s++, state++) { | |
257 | if (*s && !strncmp(buf, *s, len)) | |
258 | break; | |
259 | } | |
260 | if (*s) | |
261 | error = enter_state(state); | |
262 | else | |
263 | error = -EINVAL; | |
264 | return error ? error : n; | |
265 | } | |
266 | ||
267 | power_attr(state); | |
268 | ||
269 | static struct attribute * g[] = { | |
270 | &state_attr.attr, | |
271 | NULL, | |
272 | }; | |
273 | ||
274 | static struct attribute_group attr_group = { | |
275 | .attrs = g, | |
276 | }; | |
277 | ||
278 | ||
279 | static int __init pm_init(void) | |
280 | { | |
281 | int error = subsystem_register(&power_subsys); | |
282 | if (!error) | |
283 | error = sysfs_create_group(&power_subsys.kset.kobj,&attr_group); | |
284 | return error; | |
285 | } | |
286 | ||
287 | core_initcall(pm_init); |