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