2 * kernel/power/main.c - PM subsystem core functionality.
4 * Copyright (c) 2003 Patrick Mochel
5 * Copyright (c) 2003 Open Source Development Lab
7 * This file is released under the GPLv2
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>
18 #include <linux/console.h>
22 /*This is just an arbitrary number */
23 #define FREE_PAGE_NUMBER (100)
25 DECLARE_MUTEX(pm_sem
);
27 struct pm_ops
*pm_ops
;
28 suspend_disk_method_t pm_disk_mode
= PM_DISK_SHUTDOWN
;
31 * pm_set_ops - Set the global power method table.
32 * @ops: Pointer to ops structure.
35 void pm_set_ops(struct pm_ops
* ops
)
44 * suspend_prepare - Do prep work before entering low-power state.
45 * @state: State we're entering.
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.
52 static int suspend_prepare(suspend_state_t state
)
55 unsigned int free_pages
;
57 if (!pm_ops
|| !pm_ops
->enter
)
62 disable_nonboot_cpus();
64 if (num_online_cpus() != 1) {
69 if (freeze_processes()) {
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
) {
79 printk(KERN_ERR
"PM: No enough memory\n");
84 if (pm_ops
->prepare
) {
85 if ((error
= pm_ops
->prepare(state
)))
90 if ((error
= device_suspend(PMSG_SUSPEND
))) {
91 printk(KERN_ERR
"Some devices failed to suspend\n");
97 pm_ops
->finish(state
);
101 enable_nonboot_cpus();
102 pm_restore_console();
107 int suspend_enter(suspend_state_t state
)
112 local_irq_save(flags
);
114 if ((error
= device_power_down(PMSG_SUSPEND
))) {
115 printk(KERN_ERR
"Some devices failed to power down\n");
118 error
= pm_ops
->enter(state
);
121 local_irq_restore(flags
);
127 * suspend_finish - Do final work before exiting suspend sequence.
128 * @state: State we're coming out of.
130 * Call platform code to clean up, restart processes, and free the
131 * console that we've allocated. This is not called for suspend-to-disk.
134 static void suspend_finish(suspend_state_t state
)
139 enable_nonboot_cpus();
140 if (pm_ops
&& pm_ops
->finish
)
141 pm_ops
->finish(state
);
142 pm_restore_console();
148 static char *pm_states
[PM_SUSPEND_MAX
] = {
149 [PM_SUSPEND_STANDBY
] = "standby",
150 [PM_SUSPEND_MEM
] = "mem",
151 #ifdef CONFIG_SOFTWARE_SUSPEND
152 [PM_SUSPEND_DISK
] = "disk",
156 static inline int valid_state(suspend_state_t state
)
158 /* Suspend-to-disk does not really need low-level support.
159 * It can work with reboot if needed. */
160 if (state
== PM_SUSPEND_DISK
)
163 if (pm_ops
&& pm_ops
->valid
&& !pm_ops
->valid(state
))
170 * enter_state - Do common work of entering low-power state.
171 * @state: pm_state structure for state we're entering.
173 * Make sure we're the only ones trying to enter a sleep state. Fail
174 * if someone has beat us to it, since we don't want anything weird to
175 * happen when we wake up.
176 * Then, do the setup for suspend, enter the state, and cleaup (after
180 static int enter_state(suspend_state_t state
)
184 if (!valid_state(state
))
186 if (down_trylock(&pm_sem
))
189 if (state
== PM_SUSPEND_DISK
) {
190 error
= pm_suspend_disk();
194 pr_debug("PM: Preparing system for %s sleep\n", pm_states
[state
]);
195 if ((error
= suspend_prepare(state
)))
198 pr_debug("PM: Entering %s sleep\n", pm_states
[state
]);
199 error
= suspend_enter(state
);
201 pr_debug("PM: Finishing wakeup.\n");
202 suspend_finish(state
);
209 * This is main interface to the outside world. It needs to be
210 * called from process context.
212 int software_suspend(void)
214 return enter_state(PM_SUSPEND_DISK
);
219 * pm_suspend - Externally visible function for suspending system.
220 * @state: Enumarted value of state to enter.
222 * Determine whether or not value is within range, get state
223 * structure, and enter (above).
226 int pm_suspend(suspend_state_t state
)
228 if (state
> PM_SUSPEND_ON
&& state
<= PM_SUSPEND_MAX
)
229 return enter_state(state
);
235 decl_subsys(power
,NULL
,NULL
);
239 * state - control system power state.
241 * show() returns what states are supported, which is hard-coded to
242 * 'standby' (Power-On Suspend), 'mem' (Suspend-to-RAM), and
243 * 'disk' (Suspend-to-Disk).
245 * store() accepts one of those strings, translates it into the
246 * proper enumerated value, and initiates a suspend transition.
249 static ssize_t
state_show(struct subsystem
* subsys
, char * buf
)
254 for (i
= 0; i
< PM_SUSPEND_MAX
; i
++) {
255 if (pm_states
[i
] && valid_state(i
))
256 s
+= sprintf(s
,"%s ", pm_states
[i
]);
258 s
+= sprintf(s
,"\n");
262 static ssize_t
state_store(struct subsystem
* subsys
, const char * buf
, size_t n
)
264 suspend_state_t state
= PM_SUSPEND_STANDBY
;
270 p
= memchr(buf
, '\n', n
);
271 len
= p
? p
- buf
: n
;
273 for (s
= &pm_states
[state
]; state
< PM_SUSPEND_MAX
; s
++, state
++) {
274 if (*s
&& !strncmp(buf
, *s
, len
))
277 if (state
< PM_SUSPEND_MAX
&& *s
)
278 error
= enter_state(state
);
281 return error
? error
: n
;
286 static struct attribute
* g
[] = {
291 static struct attribute_group attr_group
= {
296 static int __init
pm_init(void)
298 int error
= subsystem_register(&power_subsys
);
300 error
= sysfs_create_group(&power_subsys
.kset
.kobj
,&attr_group
);
304 core_initcall(pm_init
);