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
  26 #include "power.h"
  27
  28 const char *const pm_states[PM_SUSPEND_MAX] = {
  29 #ifdef CONFIG_EARLYSUSPEND
  30         [PM_SUSPEND_ON]         = "on",
  31 #endif
  32         [PM_SUSPEND_STANDBY]    = "standby",
  33         [PM_SUSPEND_MEM]        = "mem",
  34 };
  35
  36 static struct platform_suspend_ops *suspend_ops;
  37
  38 /**
  39  *      suspend_set_ops - Set the global suspend method table.
  40  *      @ops:   Pointer to ops structure.
  41  */
  42 void suspend_set_ops(struct platform_suspend_ops *ops)
  43 {
  44         mutex_lock(&pm_mutex);
  45         suspend_ops = ops;
  46         mutex_unlock(&pm_mutex);
  47 }
  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
  70 static int suspend_test(int level)
  71 {
  72 #ifdef CONFIG_PM_DEBUG
  73         if (pm_test_level == level) {
  74                 printk(KERN_INFO "suspend debug: Waiting for 5 seconds.\n");
  75                 mdelay(5000);
  76                 return 1;
  77         }
  78 #endif /* !CONFIG_PM_DEBUG */
  79         return 0;
  80 }
  81
  82 /**
  83  *      suspend_prepare - Do prep work before entering low-power state.
  84  *
  85  *      This is common code that is called for each state that we're entering.
  86  *      Run suspend notifiers, allocate a console and stop all processes.
  87  */
  88 static int suspend_prepare(void)
  89 {
  90         int error;
  91
  92         if (!suspend_ops || !suspend_ops->enter)
  93                 return -EPERM;
  94
  95         pm_prepare_console();
  96
  97         error = pm_notifier_call_chain(PM_SUSPEND_PREPARE);
  98         if (error)
  99                 goto Finish;
 100
 101         error = usermodehelper_disable();
 102         if (error)
 103                 goto Finish;
 104
 105         error = suspend_freeze_processes();
 106         if (!error)
 107                 return 0;
 108
 109         suspend_thaw_processes();
 110         usermodehelper_enable();
 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 - enter the desired system sleep state.
 131  *      @state:         state to enter
 132  *
 133  *      This function should be called after devices have been suspended.
 134  */
 135 static int suspend_enter(suspend_state_t state)
 136 {
 137         int error;
 138
 139         if (suspend_ops->prepare) {
 140                 error = suspend_ops->prepare();
 141                 if (error)
 142                         goto Platform_finish;
 143         }
 144
 145         error = dpm_suspend_noirq(PMSG_SUSPEND);
 146         if (error) {
 147                 printk(KERN_ERR "PM: Some devices failed to power down\n");
 148                 goto Platform_finish;
 149         }
 150
 151         if (suspend_ops->prepare_late) {
 152                 error = suspend_ops->prepare_late();
 153                 if (error)
 154                         goto Platform_wake;
 155         }
 156
 157         if (suspend_test(TEST_PLATFORM))
 158                 goto Platform_wake;
 159
 160         error = disable_nonboot_cpus();
 161         if (error || suspend_test(TEST_CPUS))
 162                 goto Enable_cpus;
 163
 164         arch_suspend_disable_irqs();
 165         BUG_ON(!irqs_disabled());
 166
 167         error = sysdev_suspend(PMSG_SUSPEND);
 168         if (!error) {
 169                 if (!suspend_test(TEST_CORE) && pm_check_wakeup_events()) {
 170                         error = suspend_ops->enter(state);
 171                         events_check_enabled = false;
 172                 }
 173                 sysdev_resume();
 174         }
 175
 176         arch_suspend_enable_irqs();
 177         BUG_ON(irqs_disabled());
 178
 179  Enable_cpus:
 180         enable_nonboot_cpus();
 181
 182  Platform_wake:
 183         if (suspend_ops->wake)
 184                 suspend_ops->wake();
 185
 186         dpm_resume_noirq(PMSG_RESUME);
 187
 188  Platform_finish:
 189         if (suspend_ops->finish)
 190                 suspend_ops->finish();
 191
 192         return error;
 193 }
 194
 195 /**
 196  *      suspend_devices_and_enter - suspend devices and enter the desired system
 197  *                                  sleep state.
 198  *      @state:           state to enter
 199  */
 200 int suspend_devices_and_enter(suspend_state_t state)
 201 {
 202         int error;
 203
 204         if (!suspend_ops)
 205                 return -ENOSYS;
 206
 207         if (suspend_ops->begin) {
 208                 error = suspend_ops->begin(state);
 209                 if (error)
 210                         goto Close;
 211         }
 212         suspend_console();
 213         pm_restrict_gfp_mask();
 214         suspend_test_start();
 215         error = dpm_suspend_start(PMSG_SUSPEND);
 216         if (error) {
 217                 printk(KERN_ERR "PM: Some devices failed to suspend\n");
 218                 goto Recover_platform;
 219         }
 220         suspend_test_finish("suspend devices");
 221         if (suspend_test(TEST_DEVICES))
 222                 goto Recover_platform;
 223
 224         suspend_enter(state);
 225
 226  Resume_devices:
 227         suspend_test_start();
 228         dpm_resume_end(PMSG_RESUME);
 229         suspend_test_finish("resume devices");
 230         pm_restore_gfp_mask();
 231         resume_console();
 232  Close:
 233         if (suspend_ops->end)
 234                 suspend_ops->end();
 235         return error;
 236
 237  Recover_platform:
 238         if (suspend_ops->recover)
 239                 suspend_ops->recover();
 240         goto Resume_devices;
 241 }
 242
 243 /**
 244  *      suspend_finish - Do final work before exiting suspend sequence.
 245  *
 246  *      Call platform code to clean up, restart processes, and free the
 247  *      console that we've allocated. This is not called for suspend-to-disk.
 248  */
 249 static void suspend_finish(void)
 250 {
 251         suspend_thaw_processes();
 252         usermodehelper_enable();
 253         pm_notifier_call_chain(PM_POST_SUSPEND);
 254         pm_restore_console();
 255 }
 256
 257 /**
 258  *      enter_state - Do common work of entering low-power state.
 259  *      @state:         pm_state structure for state we're entering.
 260  *
 261  *      Make sure we're the only ones trying to enter a sleep state. Fail
 262  *      if someone has beat us to it, since we don't want anything weird to
 263  *      happen when we wake up.
 264  *      Then, do the setup for suspend, enter the state, and cleaup (after
 265  *      we've woken up).
 266  */
 267 int enter_state(suspend_state_t state)
 268 {
 269         int error;
 270
 271         if (!valid_state(state))
 272                 return -ENODEV;
 273
 274         if (!mutex_trylock(&pm_mutex))
 275                 return -EBUSY;
 276
 277         printk(KERN_INFO "PM: Syncing filesystems ... ");
 278         sys_sync();
 279         printk("done.\n");
 280
 281         pr_debug("PM: Preparing system for %s sleep\n", pm_states[state]);
 282         error = suspend_prepare();
 283         if (error)
 284                 goto Unlock;
 285
 286         if (suspend_test(TEST_FREEZER))
 287                 goto Finish;
 288
 289         pr_debug("PM: Entering %s sleep\n", pm_states[state]);
 290         error = suspend_devices_and_enter(state);
 291
 292  Finish:
 293         pr_debug("PM: Finishing wakeup.\n");
 294         suspend_finish();
 295  Unlock:
 296         mutex_unlock(&pm_mutex);
 297         return error;
 298 }
 299
 300 /**
 301  *      pm_suspend - Externally visible function for suspending system.
 302  *      @state:         Enumerated value of state to enter.
 303  *
 304  *      Determine whether or not value is within range, get state
 305  *      structure, and enter (above).
 306  */
 307 int pm_suspend(suspend_state_t state)
 308 {
 309         if (state > PM_SUSPEND_ON && state <= PM_SUSPEND_MAX)
 310                 return enter_state(state);
 311         return -EINVAL;
 312 }
 313 EXPORT_SYMBOL(pm_suspend);