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                 suspend_stats.failed_freeze++;
 109                 dpm_save_failed_step(SUSPEND_FREEZE);
 110         } else
 111                 return 0;
 112
 113         suspend_thaw_processes();
 114         usermodehelper_enable();
 115  Finish:
 116         pm_notifier_call_chain(PM_POST_SUSPEND);
 117         pm_restore_console();
 118         return error;
 119 }
 120
 121 /* default implementation */
 122 void __attribute__ ((weak)) arch_suspend_disable_irqs(void)
 123 {
 124         local_irq_disable();
 125 }
 126
 127 /* default implementation */
 128 void __attribute__ ((weak)) arch_suspend_enable_irqs(void)
 129 {
 130         local_irq_enable();
 131 }
 132
 133 /**
 134  * suspend_enter - enter the desired system sleep state.
 135  * @state: State to enter
 136  * @wakeup: Returns information that suspend should not be entered again.
 137  *
 138  * This function should be called after devices have been suspended.
 139  */
 140 static int suspend_enter(suspend_state_t state, bool *wakeup)
 141 {
 142         int error;
 143
 144         if (suspend_ops->prepare) {
 145                 error = suspend_ops->prepare();
 146                 if (error)
 147                         goto Platform_finish;
 148         }
 149
 150         error = dpm_suspend_noirq(PMSG_SUSPEND);
 151         if (error) {
 152                 printk(KERN_ERR "PM: Some devices failed to power down\n");
 153                 goto Platform_finish;
 154         }
 155
 156         if (suspend_ops->prepare_late) {
 157                 error = suspend_ops->prepare_late();
 158                 if (error)
 159                         goto Platform_wake;
 160         }
 161
 162         if (suspend_test(TEST_PLATFORM))
 163                 goto Platform_wake;
 164
 165         error = disable_nonboot_cpus();
 166         if (error || suspend_test(TEST_CPUS))
 167                 goto Enable_cpus;
 168
 169         arch_suspend_disable_irqs();
 170         BUG_ON(!irqs_disabled());
 171
 172         error = syscore_suspend();
 173         if (!error) {
 174                 *wakeup = pm_wakeup_pending();
 175                 if (!(suspend_test(TEST_CORE) || *wakeup)) {
 176                         error = suspend_ops->enter(state);
 177                         events_check_enabled = false;
 178                 }
 179                 syscore_resume();
 180         }
 181
 182         arch_suspend_enable_irqs();
 183         BUG_ON(irqs_disabled());
 184
 185  Enable_cpus:
 186         enable_nonboot_cpus();
 187
 188  Platform_wake:
 189         if (suspend_ops->wake)
 190                 suspend_ops->wake();
 191
 192         dpm_resume_noirq(PMSG_RESUME);
 193
 194  Platform_finish:
 195         if (suspend_ops->finish)
 196                 suspend_ops->finish();
 197
 198         return error;
 199 }
 200
 201 /**
 202  *      suspend_devices_and_enter - suspend devices and enter the desired system
 203  *                                  sleep state.
 204  *      @state:           state to enter
 205  */
 206 int suspend_devices_and_enter(suspend_state_t state)
 207 {
 208         int error;
 209         bool wakeup = false;
 210
 211         if (!suspend_ops)
 212                 return -ENOSYS;
 213
 214         trace_machine_suspend(state);
 215         if (suspend_ops->begin) {
 216                 error = suspend_ops->begin(state);
 217                 if (error)
 218                         goto Close;
 219         }
 220         suspend_console();
 221         suspend_test_start();
 222         error = dpm_suspend_start(PMSG_SUSPEND);
 223         if (error) {
 224                 printk(KERN_ERR "PM: Some devices failed to suspend\n");
 225                 goto Recover_platform;
 226         }
 227         suspend_test_finish("suspend devices");
 228         if (suspend_test(TEST_DEVICES))
 229                 goto Recover_platform;
 230
 231         do {
 232                 error = suspend_enter(state, &wakeup);
 233         } while (!error && !wakeup
 234                 && suspend_ops->suspend_again && suspend_ops->suspend_again());
 235
 236  Resume_devices:
 237         suspend_test_start();
 238         dpm_resume_end(PMSG_RESUME);
 239         suspend_test_finish("resume devices");
 240         resume_console();
 241  Close:
 242         if (suspend_ops->end)
 243                 suspend_ops->end();
 244         trace_machine_suspend(PWR_EVENT_EXIT);
 245         return error;
 246
 247  Recover_platform:
 248         if (suspend_ops->recover)
 249                 suspend_ops->recover();
 250         goto Resume_devices;
 251 }
 252
 253 /**
 254  *      suspend_finish - Do final work before exiting suspend sequence.
 255  *
 256  *      Call platform code to clean up, restart processes, and free the
 257  *      console that we've allocated. This is not called for suspend-to-disk.
 258  */
 259 static void suspend_finish(void)
 260 {
 261         suspend_thaw_processes();
 262         usermodehelper_enable();
 263         pm_notifier_call_chain(PM_POST_SUSPEND);
 264         pm_restore_console();
 265 }
 266
 267 /**
 268  *      enter_state - Do common work of entering low-power state.
 269  *      @state:         pm_state structure for state we're entering.
 270  *
 271  *      Make sure we're the only ones trying to enter a sleep state. Fail
 272  *      if someone has beat us to it, since we don't want anything weird to
 273  *      happen when we wake up.
 274  *      Then, do the setup for suspend, enter the state, and cleaup (after
 275  *      we've woken up).
 276  */
 277 int enter_state(suspend_state_t state)
 278 {
 279         int error;
 280
 281         if (!valid_state(state))
 282                 return -ENODEV;
 283
 284         if (!mutex_trylock(&pm_mutex))
 285                 return -EBUSY;
 286
 287         printk(KERN_INFO "PM: Syncing filesystems ... ");
 288         sys_sync();
 289         printk("done.\n");
 290
 291         pr_debug("PM: Preparing system for %s sleep\n", pm_states[state]);
 292         error = suspend_prepare();
 293         if (error)
 294                 goto Unlock;
 295
 296         if (suspend_test(TEST_FREEZER))
 297                 goto Finish;
 298
 299         pr_debug("PM: Entering %s sleep\n", pm_states[state]);
 300         pm_restrict_gfp_mask();
 301         error = suspend_devices_and_enter(state);
 302         pm_restore_gfp_mask();
 303
 304  Finish:
 305         pr_debug("PM: Finishing wakeup.\n");
 306         suspend_finish();
 307  Unlock:
 308         mutex_unlock(&pm_mutex);
 309         return error;
 310 }
 311
 312 /**
 313  *      pm_suspend - Externally visible function for suspending system.
 314  *      @state:         Enumerated value of state to enter.
 315  *
 316  *      Determine whether or not value is within range, get state
 317  *      structure, and enter (above).
 318  */
 319 int pm_suspend(suspend_state_t state)
 320 {
 321         int ret;
 322         if (state > PM_SUSPEND_ON && state < PM_SUSPEND_MAX) {
 323                 ret = enter_state(state);
 324                 if (ret) {
 325                         suspend_stats.fail++;
 326                         dpm_save_failed_errno(ret);
 327                 } else
 328                         suspend_stats.success++;
 329                 return ret;
 330         }
 331         return -EINVAL;
 332 }
 333 EXPORT_SYMBOL(pm_suspend);