hwmon: (max16064) Add driver documentation
[linux-2.6/linux-acpi-2.6/ibm-acpi-2.6.git] / kernel / power / suspend.c
blob2814c32aed51c121a7ff9689aa38f6b98d025b15
1 /*
2 * kernel/power/suspend.c - Suspend to RAM and standby functionality.
4 * Copyright (c) 2003 Patrick Mochel
5 * Copyright (c) 2003 Open Source Development Lab
6 * Copyright (c) 2009 Rafael J. Wysocki <rjw@sisk.pl>, Novell Inc.
8 * This file is released under the GPLv2.
9 */
11 #include <linux/string.h>
12 #include <linux/delay.h>
13 #include <linux/errno.h>
14 #include <linux/init.h>
15 #include <linux/console.h>
16 #include <linux/cpu.h>
17 #include <linux/syscalls.h>
18 #include <linux/gfp.h>
19 #include <linux/io.h>
20 #include <linux/kernel.h>
21 #include <linux/list.h>
22 #include <linux/mm.h>
23 #include <linux/slab.h>
24 #include <linux/suspend.h>
25 #include <linux/syscore_ops.h>
26 #include <trace/events/power.h>
28 #include "power.h"
30 const char *const pm_states[PM_SUSPEND_MAX] = {
31 [PM_SUSPEND_STANDBY] = "standby",
32 [PM_SUSPEND_MEM] = "mem",
35 static const struct platform_suspend_ops *suspend_ops;
37 /**
38 * suspend_set_ops - Set the global suspend method table.
39 * @ops: Pointer to ops structure.
41 void suspend_set_ops(const struct platform_suspend_ops *ops)
43 mutex_lock(&pm_mutex);
44 suspend_ops = ops;
45 mutex_unlock(&pm_mutex);
48 bool valid_state(suspend_state_t state)
51 * All states need lowlevel support and need to be valid to the lowlevel
52 * implementation, no valid callback implies that none are valid.
54 return suspend_ops && suspend_ops->valid && suspend_ops->valid(state);
57 /**
58 * suspend_valid_only_mem - generic memory-only valid callback
60 * Platform drivers that implement mem suspend only and only need
61 * to check for that in their .valid callback can use this instead
62 * of rolling their own .valid callback.
64 int suspend_valid_only_mem(suspend_state_t state)
66 return state == PM_SUSPEND_MEM;
69 static int suspend_test(int level)
71 #ifdef CONFIG_PM_DEBUG
72 if (pm_test_level == level) {
73 printk(KERN_INFO "suspend debug: Waiting for 5 seconds.\n");
74 mdelay(5000);
75 return 1;
77 #endif /* !CONFIG_PM_DEBUG */
78 return 0;
81 /**
82 * suspend_prepare - Do prep work before entering low-power state.
84 * This is common code that is called for each state that we're entering.
85 * Run suspend notifiers, allocate a console and stop all processes.
87 static int suspend_prepare(void)
89 int error;
91 if (!suspend_ops || !suspend_ops->enter)
92 return -EPERM;
94 pm_prepare_console();
96 error = pm_notifier_call_chain(PM_SUSPEND_PREPARE);
97 if (error)
98 goto Finish;
100 error = usermodehelper_disable();
101 if (error)
102 goto Finish;
104 error = suspend_freeze_processes();
105 if (!error)
106 return 0;
108 suspend_thaw_processes();
109 usermodehelper_enable();
110 Finish:
111 pm_notifier_call_chain(PM_POST_SUSPEND);
112 pm_restore_console();
113 return error;
116 /* default implementation */
117 void __attribute__ ((weak)) arch_suspend_disable_irqs(void)
119 local_irq_disable();
122 /* default implementation */
123 void __attribute__ ((weak)) arch_suspend_enable_irqs(void)
125 local_irq_enable();
129 * suspend_enter - enter the desired system sleep state.
130 * @state: state to enter
132 * This function should be called after devices have been suspended.
134 static int suspend_enter(suspend_state_t state)
136 int error;
138 if (suspend_ops->prepare) {
139 error = suspend_ops->prepare();
140 if (error)
141 goto Platform_finish;
144 error = dpm_suspend_noirq(PMSG_SUSPEND);
145 if (error) {
146 printk(KERN_ERR "PM: Some devices failed to power down\n");
147 goto Platform_finish;
150 if (suspend_ops->prepare_late) {
151 error = suspend_ops->prepare_late();
152 if (error)
153 goto Platform_wake;
156 if (suspend_test(TEST_PLATFORM))
157 goto Platform_wake;
159 error = disable_nonboot_cpus();
160 if (error || suspend_test(TEST_CPUS))
161 goto Enable_cpus;
163 arch_suspend_disable_irqs();
164 BUG_ON(!irqs_disabled());
166 error = sysdev_suspend(PMSG_SUSPEND);
167 if (!error)
168 error = syscore_suspend();
169 if (!error) {
170 if (!(suspend_test(TEST_CORE) || pm_wakeup_pending())) {
171 error = suspend_ops->enter(state);
172 events_check_enabled = false;
174 syscore_resume();
175 sysdev_resume();
178 arch_suspend_enable_irqs();
179 BUG_ON(irqs_disabled());
181 Enable_cpus:
182 enable_nonboot_cpus();
184 Platform_wake:
185 if (suspend_ops->wake)
186 suspend_ops->wake();
188 dpm_resume_noirq(PMSG_RESUME);
190 Platform_finish:
191 if (suspend_ops->finish)
192 suspend_ops->finish();
194 return error;
198 * suspend_devices_and_enter - suspend devices and enter the desired system
199 * sleep state.
200 * @state: state to enter
202 int suspend_devices_and_enter(suspend_state_t state)
204 int error;
206 if (!suspend_ops)
207 return -ENOSYS;
209 trace_machine_suspend(state);
210 if (suspend_ops->begin) {
211 error = suspend_ops->begin(state);
212 if (error)
213 goto Close;
215 suspend_console();
216 pm_restrict_gfp_mask();
217 suspend_test_start();
218 error = dpm_suspend_start(PMSG_SUSPEND);
219 if (error) {
220 printk(KERN_ERR "PM: Some devices failed to suspend\n");
221 goto Recover_platform;
223 suspend_test_finish("suspend devices");
224 if (suspend_test(TEST_DEVICES))
225 goto Recover_platform;
227 suspend_enter(state);
229 Resume_devices:
230 suspend_test_start();
231 dpm_resume_end(PMSG_RESUME);
232 suspend_test_finish("resume devices");
233 pm_restore_gfp_mask();
234 resume_console();
235 Close:
236 if (suspend_ops->end)
237 suspend_ops->end();
238 trace_machine_suspend(PWR_EVENT_EXIT);
239 return error;
241 Recover_platform:
242 if (suspend_ops->recover)
243 suspend_ops->recover();
244 goto Resume_devices;
248 * suspend_finish - Do final work before exiting suspend sequence.
250 * Call platform code to clean up, restart processes, and free the
251 * console that we've allocated. This is not called for suspend-to-disk.
253 static void suspend_finish(void)
255 suspend_thaw_processes();
256 usermodehelper_enable();
257 pm_notifier_call_chain(PM_POST_SUSPEND);
258 pm_restore_console();
262 * enter_state - Do common work of entering low-power state.
263 * @state: pm_state structure for state we're entering.
265 * Make sure we're the only ones trying to enter a sleep state. Fail
266 * if someone has beat us to it, since we don't want anything weird to
267 * happen when we wake up.
268 * Then, do the setup for suspend, enter the state, and cleaup (after
269 * we've woken up).
271 int enter_state(suspend_state_t state)
273 int error;
275 if (!valid_state(state))
276 return -ENODEV;
278 if (!mutex_trylock(&pm_mutex))
279 return -EBUSY;
281 printk(KERN_INFO "PM: Syncing filesystems ... ");
282 sys_sync();
283 printk("done.\n");
285 pr_debug("PM: Preparing system for %s sleep\n", pm_states[state]);
286 error = suspend_prepare();
287 if (error)
288 goto Unlock;
290 if (suspend_test(TEST_FREEZER))
291 goto Finish;
293 pr_debug("PM: Entering %s sleep\n", pm_states[state]);
294 error = suspend_devices_and_enter(state);
296 Finish:
297 pr_debug("PM: Finishing wakeup.\n");
298 suspend_finish();
299 Unlock:
300 mutex_unlock(&pm_mutex);
301 return error;
305 * pm_suspend - Externally visible function for suspending system.
306 * @state: Enumerated value of state to enter.
308 * Determine whether or not value is within range, get state
309 * structure, and enter (above).
311 int pm_suspend(suspend_state_t state)
313 if (state > PM_SUSPEND_ON && state <= PM_SUSPEND_MAX)
314 return enter_state(state);
315 return -EINVAL;
317 EXPORT_SYMBOL(pm_suspend);