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         [PM_SUSPEND_STANDBY]    = "standby",
  30         [PM_SUSPEND_MEM]        = "mem",
  31 };
  32
  33 static struct platform_suspend_ops *suspend_ops;
  34
  35 /**
  36  *      suspend_set_ops - Set the global suspend method table.
  37  *      @ops:   Pointer to ops structure.
  38  */
  39 void suspend_set_ops(struct platform_suspend_ops *ops)
  40 {
  41         mutex_lock(&pm_mutex);
  42         suspend_ops = ops;
  43         mutex_unlock(&pm_mutex);
  44 }
  45
  46 bool valid_state(suspend_state_t state)
  47 {
  48         /*
  49          * All states need lowlevel support and need to be valid to the lowlevel
  50          * implementation, no valid callback implies that none are valid.
  51          */
  52         return suspend_ops && suspend_ops->valid && suspend_ops->valid(state);
  53 }
  54
  55 /**
  56  * suspend_valid_only_mem - generic memory-only valid callback
  57  *
  58  * Platform drivers that implement mem suspend only and only need
  59  * to check for that in their .valid callback can use this instead
  60  * of rolling their own .valid callback.
  61  */
  62 int suspend_valid_only_mem(suspend_state_t state)
  63 {
  64         return state == PM_SUSPEND_MEM;
  65 }
  66
  67 static int suspend_test(int level)
  68 {
  69 #ifdef CONFIG_PM_DEBUG
  70         if (pm_test_level == level) {
  71                 printk(KERN_INFO "suspend debug: Waiting for 5 seconds.\n");
  72                 mdelay(5000);
  73                 return 1;
  74         }
  75 #endif /* !CONFIG_PM_DEBUG */
  76         return 0;
  77 }
  78
  79 /**
  80  *      suspend_prepare - Do prep work before entering low-power state.
  81  *
  82  *      This is common code that is called for each state that we're entering.
  83  *      Run suspend notifiers, allocate a console and stop all processes.
  84  */
  85 static int suspend_prepare(void)
  86 {
  87         int error;
  88
  89         if (!suspend_ops || !suspend_ops->enter)
  90                 return -EPERM;
  91
  92         pm_prepare_console();
  93
  94         error = pm_notifier_call_chain(PM_SUSPEND_PREPARE);
  95         if (error)
  96                 goto Finish;
  97
  98         error = usermodehelper_disable();
  99         if (error)
 100                 goto Finish;
 101
 102         error = suspend_freeze_processes();
 103         if (!error)
 104                 return 0;
 105
 106         suspend_thaw_processes();
 107         usermodehelper_enable();
 108  Finish:
 109         pm_notifier_call_chain(PM_POST_SUSPEND);
 110         pm_restore_console();
 111         return error;
 112 }
 113
 114 /* default implementation */
 115 void __attribute__ ((weak)) arch_suspend_disable_irqs(void)
 116 {
 117         local_irq_disable();
 118 }
 119
 120 /* default implementation */
 121 void __attribute__ ((weak)) arch_suspend_enable_irqs(void)
 122 {
 123         local_irq_enable();
 124 }
 125
 126 /**
 127  *      suspend_enter - enter the desired system sleep state.
 128  *      @state:         state to enter
 129  *
 130  *      This function should be called after devices have been suspended.
 131  */
 132 static int suspend_enter(suspend_state_t state)
 133 {
 134         int error;
 135
 136         if (suspend_ops->prepare) {
 137                 error = suspend_ops->prepare();
 138                 if (error)
 139                         return error;
 140         }
 141
 142         error = dpm_suspend_noirq(PMSG_SUSPEND);
 143         if (error) {
 144                 printk(KERN_ERR "PM: Some devices failed to power down\n");
 145                 goto Platfrom_finish;
 146         }
 147
 148         if (suspend_ops->prepare_late) {
 149                 error = suspend_ops->prepare_late();
 150                 if (error)
 151                         goto Power_up_devices;
 152         }
 153
 154         if (suspend_test(TEST_PLATFORM))
 155                 goto Platform_wake;
 156
 157         error = disable_nonboot_cpus();
 158         if (error || suspend_test(TEST_CPUS))
 159                 goto Enable_cpus;
 160
 161         arch_suspend_disable_irqs();
 162         BUG_ON(!irqs_disabled());
 163
 164         error = sysdev_suspend(PMSG_SUSPEND);
 165         if (!error) {
 166                 if (!suspend_test(TEST_CORE))
 167                         error = suspend_ops->enter(state);
 168                 sysdev_resume();
 169         }
 170
 171         arch_suspend_enable_irqs();
 172         BUG_ON(irqs_disabled());
 173
 174  Enable_cpus:
 175         enable_nonboot_cpus();
 176
 177  Platform_wake:
 178         if (suspend_ops->wake)
 179                 suspend_ops->wake();
 180
 181  Power_up_devices:
 182         dpm_resume_noirq(PMSG_RESUME);
 183
 184  Platfrom_finish:
 185         if (suspend_ops->finish)
 186                 suspend_ops->finish();
 187
 188         return error;
 189 }
 190
 191 /**
 192  *      suspend_devices_and_enter - suspend devices and enter the desired system
 193  *                                  sleep state.
 194  *      @state:           state to enter
 195  */
 196 int suspend_devices_and_enter(suspend_state_t state)
 197 {
 198         int error;
 199
 200         if (!suspend_ops)
 201                 return -ENOSYS;
 202
 203         if (suspend_ops->begin) {
 204                 error = suspend_ops->begin(state);
 205                 if (error)
 206                         goto Close;
 207         }
 208         suspend_console();
 209         pm_restrict_gfp_mask();
 210         suspend_test_start();
 211         error = dpm_suspend_start(PMSG_SUSPEND);
 212         if (error) {
 213                 printk(KERN_ERR "PM: Some devices failed to suspend\n");
 214                 goto Recover_platform;
 215         }
 216         suspend_test_finish("suspend devices");
 217         if (suspend_test(TEST_DEVICES))
 218                 goto Recover_platform;
 219
 220         suspend_enter(state);
 221
 222  Resume_devices:
 223         suspend_test_start();
 224         dpm_resume_end(PMSG_RESUME);
 225         suspend_test_finish("resume devices");
 226         pm_restore_gfp_mask();
 227         resume_console();
 228  Close:
 229         if (suspend_ops->end)
 230                 suspend_ops->end();
 231         return error;
 232
 233  Recover_platform:
 234         if (suspend_ops->recover)
 235                 suspend_ops->recover();
 236         goto Resume_devices;
 237 }
 238
 239 /**
 240  *      suspend_finish - Do final work before exiting suspend sequence.
 241  *
 242  *      Call platform code to clean up, restart processes, and free the
 243  *      console that we've allocated. This is not called for suspend-to-disk.
 244  */
 245 static void suspend_finish(void)
 246 {
 247         suspend_thaw_processes();
 248         usermodehelper_enable();
 249         pm_notifier_call_chain(PM_POST_SUSPEND);
 250         pm_restore_console();
 251 }
 252
 253 /**
 254  *      enter_state - Do common work of entering low-power state.
 255  *      @state:         pm_state structure for state we're entering.
 256  *
 257  *      Make sure we're the only ones trying to enter a sleep state. Fail
 258  *      if someone has beat us to it, since we don't want anything weird to
 259  *      happen when we wake up.
 260  *      Then, do the setup for suspend, enter the state, and cleaup (after
 261  *      we've woken up).
 262  */
 263 int enter_state(suspend_state_t state)
 264 {
 265         int error;
 266
 267         if (!valid_state(state))
 268                 return -ENODEV;
 269
 270         if (!mutex_trylock(&pm_mutex))
 271                 return -EBUSY;
 272
 273         printk(KERN_INFO "PM: Syncing filesystems ... ");
 274         sys_sync();
 275         printk("done.\n");
 276
 277         pr_debug("PM: Preparing system for %s sleep\n", pm_states[state]);
 278         error = suspend_prepare();
 279         if (error)
 280                 goto Unlock;
 281
 282         if (suspend_test(TEST_FREEZER))
 283                 goto Finish;
 284
 285         pr_debug("PM: Entering %s sleep\n", pm_states[state]);
 286         error = suspend_devices_and_enter(state);
 287
 288  Finish:
 289         pr_debug("PM: Finishing wakeup.\n");
 290         suspend_finish();
 291  Unlock:
 292         mutex_unlock(&pm_mutex);
 293         return error;
 294 }
 295
 296 /**
 297  *      pm_suspend - Externally visible function for suspending system.
 298  *      @state:         Enumerated value of state to enter.
 299  *
 300  *      Determine whether or not value is within range, get state
 301  *      structure, and enter (above).
 302  */
 303 int pm_suspend(suspend_state_t state)
 304 {
 305         if (state > PM_SUSPEND_ON && state <= PM_SUSPEND_MAX)
 306                 return enter_state(state);
 307         return -EINVAL;
 308 }
 309 EXPORT_SYMBOL(pm_suspend);