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
  30 const char *const pm_states[PM_SUSPEND_MAX] = {
  31         [PM_SUSPEND_STANDBY]    = "standby",
  32         [PM_SUSPEND_MEM]        = "mem",
  33 };
  34
  35 static 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  */
  41 void 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 EXPORT_SYMBOL_GPL(suspend_set_ops);
  48
  49 bool valid_state(suspend_state_t state)
  50 {
  51         /*
  52          * All states need lowlevel support and need to be valid to the lowlevel
  53          * implementation, no valid callback implies that none are valid.
  54          */
  55         return suspend_ops && suspend_ops->valid && suspend_ops->valid(state);
  56 }
  57
  58 /**
  59  * suspend_valid_only_mem - generic memory-only valid callback
  60  *
  61  * Platform drivers that implement mem suspend only and only need
  62  * to check for that in their .valid callback can use this instead
  63  * of rolling their own .valid callback.
  64  */
  65 int suspend_valid_only_mem(suspend_state_t state)
  66 {
  67         return state == PM_SUSPEND_MEM;
  68 }
  69 EXPORT_SYMBOL_GPL(suspend_valid_only_mem);
  70
  71 static int suspend_test(int level)
  72 {
  73 #ifdef CONFIG_PM_DEBUG
  74         if (pm_test_level == level) {
  75                 printk(KERN_INFO "suspend debug: Waiting for 5 seconds.\n");
  76                 mdelay(5000);
  77                 return 1;
  78         }
  79 #endif /* !CONFIG_PM_DEBUG */
  80         return 0;
  81 }
  82
  83 /**
  84  *      suspend_prepare - Do prep work before entering low-power state.
  85  *
  86  *      This is common code that is called for each state that we're entering.
  87  *      Run suspend notifiers, allocate a console and stop all processes.
  88  */
  89 static int suspend_prepare(void)
  90 {
  91         int error;
  92
  93         if (!suspend_ops || !suspend_ops->enter)
  94                 return -EPERM;
  95
  96         pm_prepare_console();
  97
  98         error = pm_notifier_call_chain(PM_SUSPEND_PREPARE);
  99         if (error)
 100                 goto Finish;
 101
 102         error = usermodehelper_disable();
 103         if (error)
 104                 goto Finish;
 105
 106         error = suspend_freeze_processes();
 107         if (!error)
 108                 return 0;
 109
 110         suspend_thaw_processes();
 111         usermodehelper_enable();
 112  Finish:
 113         pm_notifier_call_chain(PM_POST_SUSPEND);
 114         pm_restore_console();
 115         return error;
 116 }
 117
 118 /* default implementation */
 119 void __attribute__ ((weak)) arch_suspend_disable_irqs(void)
 120 {
 121         local_irq_disable();
 122 }
 123
 124 /* default implementation */
 125 void __attribute__ ((weak)) arch_suspend_enable_irqs(void)
 126 {
 127         local_irq_enable();
 128 }
 129
 130 /**
 131  * suspend_enter - enter the desired system sleep state.
 132  * @state: State to enter
 133  * @wakeup: Returns information that suspend should not be entered again.
 134  *
 135  * This function should be called after devices have been suspended.
 136  */
 137 static int suspend_enter(suspend_state_t state, bool *wakeup)
 138 {
 139         int error;
 140
 141         if (suspend_ops->prepare) {
 142                 error = suspend_ops->prepare();
 143                 if (error)
 144                         goto Platform_finish;
 145         }
 146
 147         error = dpm_suspend_noirq(PMSG_SUSPEND);
 148         if (error) {
 149                 printk(KERN_ERR "PM: Some devices failed to power down\n");
 150                 goto Platform_finish;
 151         }
 152
 153         if (suspend_ops->prepare_late) {
 154                 error = suspend_ops->prepare_late();
 155                 if (error)
 156                         goto Platform_wake;
 157         }
 158
 159         if (suspend_test(TEST_PLATFORM))
 160                 goto Platform_wake;
 161
 162         error = disable_nonboot_cpus();
 163         if (error || suspend_test(TEST_CPUS))
 164                 goto Enable_cpus;
 165
 166         arch_suspend_disable_irqs();
 167         BUG_ON(!irqs_disabled());
 168
 169         error = syscore_suspend();
 170         if (!error) {
 171                 *wakeup = pm_wakeup_pending();
 172                 if (!(suspend_test(TEST_CORE) || *wakeup)) {
 173                         error = suspend_ops->enter(state);
 174                         events_check_enabled = false;
 175                 }
 176                 syscore_resume();
 177         }
 178
 179         arch_suspend_enable_irqs();
 180         BUG_ON(irqs_disabled());
 181
 182  Enable_cpus:
 183         enable_nonboot_cpus();
 184
 185  Platform_wake:
 186         if (suspend_ops->wake)
 187                 suspend_ops->wake();
 188
 189         dpm_resume_noirq(PMSG_RESUME);
 190
 191  Platform_finish:
 192         if (suspend_ops->finish)
 193                 suspend_ops->finish();
 194
 195         return error;
 196 }
 197
 198 /**
 199  *      suspend_devices_and_enter - suspend devices and enter the desired system
 200  *                                  sleep state.
 201  *      @state:           state to enter
 202  */
 203 int suspend_devices_and_enter(suspend_state_t state)
 204 {
 205         int error;
 206         bool wakeup = false;
 207
 208         if (!suspend_ops)
 209                 return -ENOSYS;
 210
 211         trace_machine_suspend(state);
 212         if (suspend_ops->begin) {
 213                 error = suspend_ops->begin(state);
 214                 if (error)
 215                         goto Close;
 216         }
 217         suspend_console();
 218         suspend_test_start();
 219         error = dpm_suspend_start(PMSG_SUSPEND);
 220         if (error) {
 221                 printk(KERN_ERR "PM: Some devices failed to suspend\n");
 222                 goto Recover_platform;
 223         }
 224         suspend_test_finish("suspend devices");
 225         if (suspend_test(TEST_DEVICES))
 226                 goto Recover_platform;
 227
 228         do {
 229                 error = suspend_enter(state, &wakeup);
 230         } while (!error && !wakeup
 231                 && suspend_ops->suspend_again && suspend_ops->suspend_again());
 232
 233  Resume_devices:
 234         suspend_test_start();
 235         dpm_resume_end(PMSG_RESUME);
 236         suspend_test_finish("resume devices");
 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 - Do final work before exiting suspend sequence.
 252  *
 253  *      Call platform code to clean up, restart processes, and free the
 254  *      console that we've allocated. This is not called for suspend-to-disk.
 255  */
 256 static void suspend_finish(void)
 257 {
 258         suspend_thaw_processes();
 259         usermodehelper_enable();
 260         pm_notifier_call_chain(PM_POST_SUSPEND);
 261         pm_restore_console();
 262 }
 263
 264 /**
 265  *      enter_state - Do common work of entering low-power state.
 266  *      @state:         pm_state structure for state we're entering.
 267  *
 268  *      Make sure we're the only ones trying to enter a sleep state. Fail
 269  *      if someone has beat us to it, since we don't want anything weird to
 270  *      happen when we wake up.
 271  *      Then, do the setup for suspend, enter the state, and cleaup (after
 272  *      we've woken up).
 273  */
 274 int enter_state(suspend_state_t state)
 275 {
 276         int error;
 277
 278         if (!valid_state(state))
 279                 return -ENODEV;
 280
 281         if (!mutex_trylock(&pm_mutex))
 282                 return -EBUSY;
 283
 284         printk(KERN_INFO "PM: Syncing filesystems ... ");
 285         sys_sync();
 286         printk("done.\n");
 287
 288         pr_debug("PM: Preparing system for %s sleep\n", pm_states[state]);
 289         error = suspend_prepare();
 290         if (error)
 291                 goto Unlock;
 292
 293         if (suspend_test(TEST_FREEZER))
 294                 goto Finish;
 295
 296         pr_debug("PM: Entering %s sleep\n", pm_states[state]);
 297         pm_restrict_gfp_mask();
 298         error = suspend_devices_and_enter(state);
 299         pm_restore_gfp_mask();
 300
 301  Finish:
 302         pr_debug("PM: Finishing wakeup.\n");
 303         suspend_finish();
 304  Unlock:
 305         mutex_unlock(&pm_mutex);
 306         return error;
 307 }
 308
 309 /**
 310  *      pm_suspend - Externally visible function for suspending system.
 311  *      @state:         Enumerated value of state to enter.
 312  *
 313  *      Determine whether or not value is within range, get state
 314  *      structure, and enter (above).
 315  */
 316 int pm_suspend(suspend_state_t state)
 317 {
 318         if (state > PM_SUSPEND_ON && state < PM_SUSPEND_MAX)
 319                 return enter_state(state);
 320         return -EINVAL;
 321 }
 322 EXPORT_SYMBOL(pm_suspend);