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
  19 #include "power.h"
  20
  21 const char *const pm_states[PM_SUSPEND_MAX] = {
  22 #ifdef CONFIG_EARLYSUSPEND
  23         [PM_SUSPEND_ON]         = "on",
  24 #endif
  25         [PM_SUSPEND_STANDBY]    = "standby",
  26         [PM_SUSPEND_MEM]        = "mem",
  27 };
  28
  29 static struct platform_suspend_ops *suspend_ops;
  30
  31 /**
  32  *      suspend_set_ops - Set the global suspend method table.
  33  *      @ops:   Pointer to ops structure.
  34  */
  35 void suspend_set_ops(struct platform_suspend_ops *ops)
  36 {
  37         mutex_lock(&pm_mutex);
  38         suspend_ops = ops;
  39         mutex_unlock(&pm_mutex);
  40 }
  41
  42 bool valid_state(suspend_state_t state)
  43 {
  44         /*
  45          * All states need lowlevel support and need to be valid to the lowlevel
  46          * implementation, no valid callback implies that none are valid.
  47          */
  48         return suspend_ops && suspend_ops->valid && suspend_ops->valid(state);
  49 }
  50
  51 /**
  52  * suspend_valid_only_mem - generic memory-only valid callback
  53  *
  54  * Platform drivers that implement mem suspend only and only need
  55  * to check for that in their .valid callback can use this instead
  56  * of rolling their own .valid callback.
  57  */
  58 int suspend_valid_only_mem(suspend_state_t state)
  59 {
  60         return state == PM_SUSPEND_MEM;
  61 }
  62
  63 static int suspend_test(int level)
  64 {
  65 #ifdef CONFIG_PM_DEBUG
  66         if (pm_test_level == level) {
  67                 printk(KERN_INFO "suspend debug: Waiting for 5 seconds.\n");
  68                 mdelay(5000);
  69                 return 1;
  70         }
  71 #endif /* !CONFIG_PM_DEBUG */
  72         return 0;
  73 }
  74
  75 /**
  76  *      suspend_prepare - Do prep work before entering low-power state.
  77  *
  78  *      This is common code that is called for each state that we're entering.
  79  *      Run suspend notifiers, allocate a console and stop all processes.
  80  */
  81 static int suspend_prepare(void)
  82 {
  83         int error;
  84
  85         if (!suspend_ops || !suspend_ops->enter)
  86                 return -EPERM;
  87
  88         pm_prepare_console();
  89
  90         error = pm_notifier_call_chain(PM_SUSPEND_PREPARE);
  91         if (error)
  92                 goto Finish;
  93
  94         error = usermodehelper_disable();
  95         if (error)
  96                 goto Finish;
  97
  98         error = suspend_freeze_processes();
  99         if (!error)
 100                 return 0;
 101
 102         suspend_thaw_processes();
 103         usermodehelper_enable();
 104  Finish:
 105         pm_notifier_call_chain(PM_POST_SUSPEND);
 106         pm_restore_console();
 107         return error;
 108 }
 109
 110 /* default implementation */
 111 void __attribute__ ((weak)) arch_suspend_disable_irqs(void)
 112 {
 113         local_irq_disable();
 114 }
 115
 116 /* default implementation */
 117 void __attribute__ ((weak)) arch_suspend_enable_irqs(void)
 118 {
 119         local_irq_enable();
 120 }
 121
 122 /**
 123  *      suspend_enter - enter the desired system sleep state.
 124  *      @state:         state to enter
 125  *
 126  *      This function should be called after devices have been suspended.
 127  */
 128 static int suspend_enter(suspend_state_t state)
 129 {
 130         int error;
 131
 132         if (suspend_ops->prepare) {
 133                 error = suspend_ops->prepare();
 134                 if (error)
 135                         return error;
 136         }
 137
 138         error = dpm_suspend_noirq(PMSG_SUSPEND);
 139         if (error) {
 140                 printk(KERN_ERR "PM: Some devices failed to power down\n");
 141                 goto Platfrom_finish;
 142         }
 143
 144         if (suspend_ops->prepare_late) {
 145                 error = suspend_ops->prepare_late();
 146                 if (error)
 147                         goto Power_up_devices;
 148         }
 149
 150         if (suspend_test(TEST_PLATFORM))
 151                 goto Platform_wake;
 152
 153         error = disable_nonboot_cpus();
 154         if (error || suspend_test(TEST_CPUS))
 155                 goto Enable_cpus;
 156
 157         arch_suspend_disable_irqs();
 158         BUG_ON(!irqs_disabled());
 159
 160         error = sysdev_suspend(PMSG_SUSPEND);
 161         if (!error) {
 162                 if (!suspend_test(TEST_CORE))
 163                         error = suspend_ops->enter(state);
 164                 sysdev_resume();
 165         }
 166
 167         arch_suspend_enable_irqs();
 168         BUG_ON(irqs_disabled());
 169
 170  Enable_cpus:
 171         enable_nonboot_cpus();
 172
 173  Platform_wake:
 174         if (suspend_ops->wake)
 175                 suspend_ops->wake();
 176
 177  Power_up_devices:
 178         dpm_resume_noirq(PMSG_RESUME);
 179
 180  Platfrom_finish:
 181         if (suspend_ops->finish)
 182                 suspend_ops->finish();
 183
 184         return error;
 185 }
 186
 187 /**
 188  *      suspend_devices_and_enter - suspend devices and enter the desired system
 189  *                                  sleep state.
 190  *      @state:           state to enter
 191  */
 192 int suspend_devices_and_enter(suspend_state_t state)
 193 {
 194         int error;
 195
 196         if (!suspend_ops)
 197                 return -ENOSYS;
 198
 199         if (suspend_ops->begin) {
 200                 error = suspend_ops->begin(state);
 201                 if (error)
 202                         goto Close;
 203         }
 204         suspend_console();
 205         suspend_test_start();
 206         error = dpm_suspend_start(PMSG_SUSPEND);
 207         if (error) {
 208                 printk(KERN_ERR "PM: Some devices failed to suspend\n");
 209                 goto Recover_platform;
 210         }
 211         suspend_test_finish("suspend devices");
 212         if (suspend_test(TEST_DEVICES))
 213                 goto Recover_platform;
 214
 215         suspend_enter(state);
 216
 217  Resume_devices:
 218         suspend_test_start();
 219         dpm_resume_end(PMSG_RESUME);
 220         suspend_test_finish("resume devices");
 221         resume_console();
 222  Close:
 223         if (suspend_ops->end)
 224                 suspend_ops->end();
 225         return error;
 226
 227  Recover_platform:
 228         if (suspend_ops->recover)
 229                 suspend_ops->recover();
 230         goto Resume_devices;
 231 }
 232
 233 /**
 234  *      suspend_finish - Do final work before exiting suspend sequence.
 235  *
 236  *      Call platform code to clean up, restart processes, and free the
 237  *      console that we've allocated. This is not called for suspend-to-disk.
 238  */
 239 static void suspend_finish(void)
 240 {
 241         suspend_thaw_processes();
 242         usermodehelper_enable();
 243         pm_notifier_call_chain(PM_POST_SUSPEND);
 244         pm_restore_console();
 245 }
 246
 247 /**
 248  *      enter_state - Do common work of entering low-power state.
 249  *      @state:         pm_state structure for state we're entering.
 250  *
 251  *      Make sure we're the only ones trying to enter a sleep state. Fail
 252  *      if someone has beat us to it, since we don't want anything weird to
 253  *      happen when we wake up.
 254  *      Then, do the setup for suspend, enter the state, and cleaup (after
 255  *      we've woken up).
 256  */
 257 int enter_state(suspend_state_t state)
 258 {
 259         int error;
 260
 261         if (!valid_state(state))
 262                 return -ENODEV;
 263
 264         if (!mutex_trylock(&pm_mutex))
 265                 return -EBUSY;
 266
 267         printk(KERN_INFO "PM: Syncing filesystems ... ");
 268         sys_sync();
 269         printk("done.\n");
 270
 271         pr_debug("PM: Preparing system for %s sleep\n", pm_states[state]);
 272         error = suspend_prepare();
 273         if (error)
 274                 goto Unlock;
 275
 276         if (suspend_test(TEST_FREEZER))
 277                 goto Finish;
 278
 279         pr_debug("PM: Entering %s sleep\n", pm_states[state]);
 280         error = suspend_devices_and_enter(state);
 281
 282  Finish:
 283         pr_debug("PM: Finishing wakeup.\n");
 284         suspend_finish();
 285  Unlock:
 286         mutex_unlock(&pm_mutex);
 287         return error;
 288 }
 289
 290 /**
 291  *      pm_suspend - Externally visible function for suspending system.
 292  *      @state:         Enumerated value of state to enter.
 293  *
 294  *      Determine whether or not value is within range, get state
 295  *      structure, and enter (above).
 296  */
 297 int pm_suspend(suspend_state_t state)
 298 {
 299         if (state > PM_SUSPEND_ON && state <= PM_SUSPEND_MAX)
 300                 return enter_state(state);
 301         return -EINVAL;
 302 }
 303 EXPORT_SYMBOL(pm_suspend);