Root/kernel/power/suspend.c

1/*
2 * kernel/power/suspend.c - Suspend to RAM and standby functionality.
3 *
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.
7 *
8 * This file is released under the GPLv2.
9 */
10
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>
27
28#include "power.h"
29
30const char *const pm_states[PM_SUSPEND_MAX] = {
31    [PM_SUSPEND_STANDBY] = "standby",
32    [PM_SUSPEND_MEM] = "mem",
33};
34
35static const struct platform_suspend_ops *suspend_ops;
36
37/**
38 * suspend_set_ops - Set the global suspend method table.
39 * @ops: Pointer to ops structure.
40 */
41void suspend_set_ops(const struct platform_suspend_ops *ops)
42{
43    mutex_lock(&pm_mutex);
44    suspend_ops = ops;
45    mutex_unlock(&pm_mutex);
46}
47
48bool valid_state(suspend_state_t state)
49{
50    /*
51     * All states need lowlevel support and need to be valid to the lowlevel
52     * implementation, no valid callback implies that none are valid.
53     */
54    return suspend_ops && suspend_ops->valid && suspend_ops->valid(state);
55}
56
57/**
58 * suspend_valid_only_mem - generic memory-only valid callback
59 *
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.
63 */
64int suspend_valid_only_mem(suspend_state_t state)
65{
66    return state == PM_SUSPEND_MEM;
67}
68
69static int suspend_test(int level)
70{
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;
76    }
77#endif /* !CONFIG_PM_DEBUG */
78    return 0;
79}
80
81/**
82 * suspend_prepare - Do prep work before entering low-power state.
83 *
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.
86 */
87static int suspend_prepare(void)
88{
89    int error;
90
91    if (!suspend_ops || !suspend_ops->enter)
92        return -EPERM;
93
94    pm_prepare_console();
95
96    error = pm_notifier_call_chain(PM_SUSPEND_PREPARE);
97    if (error)
98        goto Finish;
99
100    error = usermodehelper_disable();
101    if (error)
102        goto Finish;
103
104    error = suspend_freeze_processes();
105    if (!error)
106        return 0;
107
108    suspend_thaw_processes();
109    usermodehelper_enable();
110 Finish:
111    pm_notifier_call_chain(PM_POST_SUSPEND);
112    pm_restore_console();
113    return error;
114}
115
116/* default implementation */
117void __attribute__ ((weak)) arch_suspend_disable_irqs(void)
118{
119    local_irq_disable();
120}
121
122/* default implementation */
123void __attribute__ ((weak)) arch_suspend_enable_irqs(void)
124{
125    local_irq_enable();
126}
127
128/**
129 * suspend_enter - enter the desired system sleep state.
130 * @state: state to enter
131 *
132 * This function should be called after devices have been suspended.
133 */
134static int suspend_enter(suspend_state_t state)
135{
136    int error;
137
138    if (suspend_ops->prepare) {
139        error = suspend_ops->prepare();
140        if (error)
141            goto Platform_finish;
142    }
143
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;
148    }
149
150    if (suspend_ops->prepare_late) {
151        error = suspend_ops->prepare_late();
152        if (error)
153            goto Platform_wake;
154    }
155
156    if (suspend_test(TEST_PLATFORM))
157        goto Platform_wake;
158
159    error = disable_nonboot_cpus();
160    if (error || suspend_test(TEST_CPUS))
161        goto Enable_cpus;
162
163    arch_suspend_disable_irqs();
164    BUG_ON(!irqs_disabled());
165
166    error = syscore_suspend();
167    if (!error) {
168        if (!(suspend_test(TEST_CORE) || pm_wakeup_pending())) {
169            error = suspend_ops->enter(state);
170            events_check_enabled = false;
171        }
172        syscore_resume();
173    }
174
175    arch_suspend_enable_irqs();
176    BUG_ON(irqs_disabled());
177
178 Enable_cpus:
179    enable_nonboot_cpus();
180
181 Platform_wake:
182    if (suspend_ops->wake)
183        suspend_ops->wake();
184
185    dpm_resume_noirq(PMSG_RESUME);
186
187 Platform_finish:
188    if (suspend_ops->finish)
189        suspend_ops->finish();
190
191    return error;
192}
193
194/**
195 * suspend_devices_and_enter - suspend devices and enter the desired system
196 * sleep state.
197 * @state: state to enter
198 */
199int suspend_devices_and_enter(suspend_state_t state)
200{
201    int error;
202
203    if (!suspend_ops)
204        return -ENOSYS;
205
206    trace_machine_suspend(state);
207    if (suspend_ops->begin) {
208        error = suspend_ops->begin(state);
209        if (error)
210            goto Close;
211    }
212    suspend_console();
213    suspend_test_start();
214    error = dpm_suspend_start(PMSG_SUSPEND);
215    if (error) {
216        printk(KERN_ERR "PM: Some devices failed to suspend\n");
217        goto Recover_platform;
218    }
219    suspend_test_finish("suspend devices");
220    if (suspend_test(TEST_DEVICES))
221        goto Recover_platform;
222
223    error = suspend_enter(state);
224
225 Resume_devices:
226    suspend_test_start();
227    dpm_resume_end(PMSG_RESUME);
228    suspend_test_finish("resume devices");
229    resume_console();
230 Close:
231    if (suspend_ops->end)
232        suspend_ops->end();
233    trace_machine_suspend(PWR_EVENT_EXIT);
234    return error;
235
236 Recover_platform:
237    if (suspend_ops->recover)
238        suspend_ops->recover();
239    goto Resume_devices;
240}
241
242/**
243 * suspend_finish - Do final work before exiting suspend sequence.
244 *
245 * Call platform code to clean up, restart processes, and free the
246 * console that we've allocated. This is not called for suspend-to-disk.
247 */
248static void suspend_finish(void)
249{
250    suspend_thaw_processes();
251    usermodehelper_enable();
252    pm_notifier_call_chain(PM_POST_SUSPEND);
253    pm_restore_console();
254}
255
256/**
257 * enter_state - Do common work of entering low-power state.
258 * @state: pm_state structure for state we're entering.
259 *
260 * Make sure we're the only ones trying to enter a sleep state. Fail
261 * if someone has beat us to it, since we don't want anything weird to
262 * happen when we wake up.
263 * Then, do the setup for suspend, enter the state, and cleaup (after
264 * we've woken up).
265 */
266int enter_state(suspend_state_t state)
267{
268    int error;
269
270    if (!valid_state(state))
271        return -ENODEV;
272
273    if (!mutex_trylock(&pm_mutex))
274        return -EBUSY;
275
276    printk(KERN_INFO "PM: Syncing filesystems ... ");
277    sys_sync();
278    printk("done.\n");
279
280    pr_debug("PM: Preparing system for %s sleep\n", pm_states[state]);
281    error = suspend_prepare();
282    if (error)
283        goto Unlock;
284
285    if (suspend_test(TEST_FREEZER))
286        goto Finish;
287
288    pr_debug("PM: Entering %s sleep\n", pm_states[state]);
289    pm_restrict_gfp_mask();
290    error = suspend_devices_and_enter(state);
291    pm_restore_gfp_mask();
292
293 Finish:
294    pr_debug("PM: Finishing wakeup.\n");
295    suspend_finish();
296 Unlock:
297    mutex_unlock(&pm_mutex);
298    return error;
299}
300
301/**
302 * pm_suspend - Externally visible function for suspending system.
303 * @state: Enumerated value of state to enter.
304 *
305 * Determine whether or not value is within range, get state
306 * structure, and enter (above).
307 */
308int pm_suspend(suspend_state_t state)
309{
310    if (state > PM_SUSPEND_ON && state <= PM_SUSPEND_MAX)
311        return enter_state(state);
312    return -EINVAL;
313}
314EXPORT_SYMBOL(pm_suspend);
315

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