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 <linux/ftrace.h>
  27 #include <trace/events/power.h>
  28
  29 #include "power.h"
  30
  31 const char *const pm_states[PM_SUSPEND_MAX] = {
  32         [PM_SUSPEND_STANDBY]    = "standby",
  33         [PM_SUSPEND_MEM]        = "mem",
  34 };
  35
  36 static const 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(const 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 = syscore_suspend();
 168         if (!error) {
 169                 if (!(suspend_test(TEST_CORE) || pm_wakeup_pending())) {
 170                         error = suspend_ops->enter(state);
 171                         events_check_enabled = false;
 172                 }
 173                 syscore_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         trace_machine_suspend(state);
 208         if (suspend_ops->begin) {
 209                 error = suspend_ops->begin(state);
 210                 if (error)
 211                         goto Close;
 212         }
 213         suspend_console();
 214         ftrace_stop();
 215         suspend_test_start();
 216         error = dpm_suspend_start(PMSG_SUSPEND);
 217         if (error) {
 218                 printk(KERN_ERR "PM: Some devices failed to suspend\n");
 219                 goto Recover_platform;
 220         }
 221         suspend_test_finish("suspend devices");
 222         if (suspend_test(TEST_DEVICES))
 223                 goto Recover_platform;
 224
 225         error = suspend_enter(state);
 226
 227  Resume_devices:
 228         suspend_test_start();
 229         dpm_resume_end(PMSG_RESUME);
 230         suspend_test_finish("resume devices");
 231         ftrace_start();
 232         resume_console();
 233  Close:
 234         if (suspend_ops->end)
 235                 suspend_ops->end();
 236         trace_machine_suspend(PWR_EVENT_EXIT);
 237         return error;
 238
 239  Recover_platform:
 240         if (suspend_ops->recover)
 241                 suspend_ops->recover();
 242         goto Resume_devices;
 243 }
 244
 245 /**
 246  *      suspend_finish - Do final work before exiting suspend sequence.
 247  *
 248  *      Call platform code to clean up, restart processes, and free the
 249  *      console that we've allocated. This is not called for suspend-to-disk.
 250  */
 251 static void suspend_finish(void)
 252 {
 253         suspend_thaw_processes();
 254         usermodehelper_enable();
 255         pm_notifier_call_chain(PM_POST_SUSPEND);
 256         pm_restore_console();
 257 }
 258
 259 /**
 260  *      enter_state - Do common work of entering low-power state.
 261  *      @state:         pm_state structure for state we're entering.
 262  *
 263  *      Make sure we're the only ones trying to enter a sleep state. Fail
 264  *      if someone has beat us to it, since we don't want anything weird to
 265  *      happen when we wake up.
 266  *      Then, do the setup for suspend, enter the state, and cleaup (after
 267  *      we've woken up).
 268  */
 269 int enter_state(suspend_state_t state)
 270 {
 271         int error;
 272
 273         if (!valid_state(state))
 274                 return -ENODEV;
 275
 276         if (!mutex_trylock(&pm_mutex))
 277                 return -EBUSY;
 278
 279         printk(KERN_INFO "PM: Syncing filesystems ... ");
 280         sys_sync();
 281         printk("done.\n");
 282
 283         pr_debug("PM: Preparing system for %s sleep\n", pm_states[state]);
 284         error = suspend_prepare();
 285         if (error)
 286                 goto Unlock;
 287
 288         if (suspend_test(TEST_FREEZER))
 289                 goto Finish;
 290
 291         pr_debug("PM: Entering %s sleep\n", pm_states[state]);
 292         pm_restrict_gfp_mask();
 293         error = suspend_devices_and_enter(state);
 294         pm_restore_gfp_mask();
 295
 296  Finish:
 297         pr_debug("PM: Finishing wakeup.\n");
 298         suspend_finish();
 299  Unlock:
 300         mutex_unlock(&pm_mutex);
 301         return error;
 302 }
 303
 304 /**
 305  *      pm_suspend - Externally visible function for suspending system.
 306  *      @state:         Enumerated value of state to enter.
 307  *
 308  *      Determine whether or not value is within range, get state
 309  *      structure, and enter (above).
 310  */
 311 int pm_suspend(suspend_state_t state)
 312 {
 313         if (state > PM_SUSPEND_ON && state < PM_SUSPEND_MAX)
 314                 return enter_state(state);
 315         return -EINVAL;
 316 }
 317 EXPORT_SYMBOL(pm_suspend);