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
  48 bool 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  */
  64 int suspend_valid_only_mem(suspend_state_t state)
  65 {
  66         return state == PM_SUSPEND_MEM;
  67 }
  68
  69 static 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  */
  87 static 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 */
 117 void __attribute__ ((weak)) arch_suspend_disable_irqs(void)
 118 {
 119         local_irq_disable();
 120 }
 121
 122 /* default implementation */
 123 void __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  */
 134 static 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  */
 199 int 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  */
 248 static 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  */
 266 int 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  */
 308 int 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 }
 314 EXPORT_SYMBOL(pm_suspend);