xref: /openbmc/linux/kernel/power/suspend.c (revision 15e47304)
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/export.h>
25 #include <linux/suspend.h>
26 #include <linux/syscore_ops.h>
27 #include <linux/ftrace.h>
28 #include <trace/events/power.h>
29 
30 #include "power.h"
31 
32 const char *const pm_states[PM_SUSPEND_MAX] = {
33 	[PM_SUSPEND_STANDBY]	= "standby",
34 	[PM_SUSPEND_MEM]	= "mem",
35 };
36 
37 static const struct platform_suspend_ops *suspend_ops;
38 
39 /**
40  * suspend_set_ops - Set the global suspend method table.
41  * @ops: Suspend operations to use.
42  */
43 void suspend_set_ops(const struct platform_suspend_ops *ops)
44 {
45 	lock_system_sleep();
46 	suspend_ops = ops;
47 	unlock_system_sleep();
48 }
49 EXPORT_SYMBOL_GPL(suspend_set_ops);
50 
51 bool valid_state(suspend_state_t state)
52 {
53 	/*
54 	 * All states need lowlevel support and need to be valid to the lowlevel
55 	 * implementation, no valid callback implies that none are valid.
56 	 */
57 	return suspend_ops && suspend_ops->valid && suspend_ops->valid(state);
58 }
59 
60 /**
61  * suspend_valid_only_mem - Generic memory-only valid callback.
62  *
63  * Platform drivers that implement mem suspend only and only need to check for
64  * that in their .valid() callback can use this instead of rolling their own
65  * .valid() callback.
66  */
67 int suspend_valid_only_mem(suspend_state_t state)
68 {
69 	return state == PM_SUSPEND_MEM;
70 }
71 EXPORT_SYMBOL_GPL(suspend_valid_only_mem);
72 
73 static int suspend_test(int level)
74 {
75 #ifdef CONFIG_PM_DEBUG
76 	if (pm_test_level == level) {
77 		printk(KERN_INFO "suspend debug: Waiting for 5 seconds.\n");
78 		mdelay(5000);
79 		return 1;
80 	}
81 #endif /* !CONFIG_PM_DEBUG */
82 	return 0;
83 }
84 
85 /**
86  * suspend_prepare - Prepare for entering system sleep state.
87  *
88  * Common code run for every system sleep state that can be entered (except for
89  * hibernation).  Run suspend notifiers, allocate the "suspend" console and
90  * freeze processes.
91  */
92 static int suspend_prepare(void)
93 {
94 	int error;
95 
96 	if (!suspend_ops || !suspend_ops->enter)
97 		return -EPERM;
98 
99 	pm_prepare_console();
100 
101 	error = pm_notifier_call_chain(PM_SUSPEND_PREPARE);
102 	if (error)
103 		goto Finish;
104 
105 	error = suspend_freeze_processes();
106 	if (!error)
107 		return 0;
108 
109 	suspend_stats.failed_freeze++;
110 	dpm_save_failed_step(SUSPEND_FREEZE);
111  Finish:
112 	pm_notifier_call_chain(PM_POST_SUSPEND);
113 	pm_restore_console();
114 	return error;
115 }
116 
117 /* default implementation */
118 void __attribute__ ((weak)) arch_suspend_disable_irqs(void)
119 {
120 	local_irq_disable();
121 }
122 
123 /* default implementation */
124 void __attribute__ ((weak)) arch_suspend_enable_irqs(void)
125 {
126 	local_irq_enable();
127 }
128 
129 /**
130  * suspend_enter - Make the system enter the given sleep state.
131  * @state: System sleep state to enter.
132  * @wakeup: Returns information that the sleep state should not be re-entered.
133  *
134  * This function should be called after devices have been suspended.
135  */
136 static int suspend_enter(suspend_state_t state, bool *wakeup)
137 {
138 	int error;
139 
140 	if (suspend_ops->prepare) {
141 		error = suspend_ops->prepare();
142 		if (error)
143 			goto Platform_finish;
144 	}
145 
146 	error = dpm_suspend_end(PMSG_SUSPEND);
147 	if (error) {
148 		printk(KERN_ERR "PM: Some devices failed to power down\n");
149 		goto Platform_finish;
150 	}
151 
152 	if (suspend_ops->prepare_late) {
153 		error = suspend_ops->prepare_late();
154 		if (error)
155 			goto Platform_wake;
156 	}
157 
158 	if (suspend_test(TEST_PLATFORM))
159 		goto Platform_wake;
160 
161 	error = disable_nonboot_cpus();
162 	if (error || suspend_test(TEST_CPUS))
163 		goto Enable_cpus;
164 
165 	arch_suspend_disable_irqs();
166 	BUG_ON(!irqs_disabled());
167 
168 	error = syscore_suspend();
169 	if (!error) {
170 		*wakeup = pm_wakeup_pending();
171 		if (!(suspend_test(TEST_CORE) || *wakeup)) {
172 			error = suspend_ops->enter(state);
173 			events_check_enabled = false;
174 		}
175 		syscore_resume();
176 	}
177 
178 	arch_suspend_enable_irqs();
179 	BUG_ON(irqs_disabled());
180 
181  Enable_cpus:
182 	enable_nonboot_cpus();
183 
184  Platform_wake:
185 	if (suspend_ops->wake)
186 		suspend_ops->wake();
187 
188 	dpm_resume_start(PMSG_RESUME);
189 
190  Platform_finish:
191 	if (suspend_ops->finish)
192 		suspend_ops->finish();
193 
194 	return error;
195 }
196 
197 /**
198  * suspend_devices_and_enter - Suspend devices and enter system sleep state.
199  * @state: System sleep state to enter.
200  */
201 int suspend_devices_and_enter(suspend_state_t state)
202 {
203 	int error;
204 	bool wakeup = false;
205 
206 	if (!suspend_ops)
207 		return -ENOSYS;
208 
209 	trace_machine_suspend(state);
210 	if (suspend_ops->begin) {
211 		error = suspend_ops->begin(state);
212 		if (error)
213 			goto Close;
214 	}
215 	suspend_console();
216 	ftrace_stop();
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;
222 	}
223 	suspend_test_finish("suspend devices");
224 	if (suspend_test(TEST_DEVICES))
225 		goto Recover_platform;
226 
227 	do {
228 		error = suspend_enter(state, &wakeup);
229 	} while (!error && !wakeup
230 		&& suspend_ops->suspend_again && suspend_ops->suspend_again());
231 
232  Resume_devices:
233 	suspend_test_start();
234 	dpm_resume_end(PMSG_RESUME);
235 	suspend_test_finish("resume devices");
236 	ftrace_start();
237 	resume_console();
238  Close:
239 	if (suspend_ops->end)
240 		suspend_ops->end();
241 	trace_machine_suspend(PWR_EVENT_EXIT);
242 	return error;
243 
244  Recover_platform:
245 	if (suspend_ops->recover)
246 		suspend_ops->recover();
247 	goto Resume_devices;
248 }
249 
250 /**
251  * suspend_finish - Clean up before finishing the suspend sequence.
252  *
253  * Call platform code to clean up, restart processes, and free the console that
254  * we've allocated. This routine is not called for hibernation.
255  */
256 static void suspend_finish(void)
257 {
258 	suspend_thaw_processes();
259 	pm_notifier_call_chain(PM_POST_SUSPEND);
260 	pm_restore_console();
261 }
262 
263 /**
264  * enter_state - Do common work needed to enter system sleep state.
265  * @state: System sleep state to enter.
266  *
267  * Make sure that no one else is trying to put the system into a sleep state.
268  * Fail if that's not the case.  Otherwise, prepare for system suspend, make the
269  * system enter the given sleep state and clean up after wakeup.
270  */
271 static int enter_state(suspend_state_t state)
272 {
273 	int error;
274 
275 	if (!valid_state(state))
276 		return -ENODEV;
277 
278 	if (!mutex_trylock(&pm_mutex))
279 		return -EBUSY;
280 
281 	printk(KERN_INFO "PM: Syncing filesystems ... ");
282 	sys_sync();
283 	printk("done.\n");
284 
285 	pr_debug("PM: Preparing system for %s sleep\n", pm_states[state]);
286 	error = suspend_prepare();
287 	if (error)
288 		goto Unlock;
289 
290 	if (suspend_test(TEST_FREEZER))
291 		goto Finish;
292 
293 	pr_debug("PM: Entering %s sleep\n", pm_states[state]);
294 	pm_restrict_gfp_mask();
295 	error = suspend_devices_and_enter(state);
296 	pm_restore_gfp_mask();
297 
298  Finish:
299 	pr_debug("PM: Finishing wakeup.\n");
300 	suspend_finish();
301  Unlock:
302 	mutex_unlock(&pm_mutex);
303 	return error;
304 }
305 
306 /**
307  * pm_suspend - Externally visible function for suspending the system.
308  * @state: System sleep state to enter.
309  *
310  * Check if the value of @state represents one of the supported states,
311  * execute enter_state() and update system suspend statistics.
312  */
313 int pm_suspend(suspend_state_t state)
314 {
315 	int error;
316 
317 	if (state <= PM_SUSPEND_ON || state >= PM_SUSPEND_MAX)
318 		return -EINVAL;
319 
320 	error = enter_state(state);
321 	if (error) {
322 		suspend_stats.fail++;
323 		dpm_save_failed_errno(error);
324 	} else {
325 		suspend_stats.success++;
326 	}
327 	return error;
328 }
329 EXPORT_SYMBOL(pm_suspend);
330