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 <trace/events/power.h>
  27
  28 #include "power.h"
  29
  30 const char *const pm_states[PM_SUSPEND_MAX] = {
  31         [PM_SUSPEND_STANDBY]    = "standby",
  32         [PM_SUSPEND_MEM]        = "mem",
  33 };
  34
  35 static const struct platform_suspend_ops *suspend_ops;
  36
  37 /**
  38  *      suspend_set_ops - Set the global suspend method table.
  39  *      @ops:   Pointer to ops structure.
  40  */
  41 void suspend_set_ops(const struct platform_suspend_ops *ops)
  42 {
  43         mutex_lock(&pm_mutex);
  44         suspend_ops = ops;
  45         mutex_unlock(&pm_mutex);
  46 }
  47
  48 bool valid_state(suspend_state_t state)
  49 {
  50         /*
  51          * All states need lowlevel support and need to be valid to the lowlevel
  52          * implementation, no valid callback implies that none are valid.
  53          */
  54         return suspend_ops && suspend_ops->valid && suspend_ops->valid(state);
  55 }
  56
  57 /**
  58  * suspend_valid_only_mem - generic memory-only valid callback
  59  *
  60  * Platform drivers that implement mem suspend only and only need
  61  * to check for that in their .valid callback can use this instead
  62  * of rolling their own .valid callback.
  63  */
  64 int suspend_valid_only_mem(suspend_state_t state)
  65 {
  66         return state == PM_SUSPEND_MEM;
  67 }
  68
  69 static int suspend_test(int level)
  70 {
  71 #ifdef CONFIG_PM_DEBUG
  72         if (pm_test_level == level) {
  73                 printk(KERN_INFO "suspend debug: Waiting for 5 seconds.\n");
  74                 mdelay(5000);
  75                 return 1;
  76         }
  77 #endif /* !CONFIG_PM_DEBUG */
  78         return 0;
  79 }
  80
  81 /**
  82  *      suspend_prepare - Do prep work before entering low-power state.
  83  *
  84  *      This is common code that is called for each state that we're entering.
  85  *      Run suspend notifiers, allocate a console and stop all processes.
  86  */
  87 static int suspend_prepare(void)
  88 {
  89         int error;
  90
  91         if (!suspend_ops || !suspend_ops->enter)
  92                 return -EPERM;
  93
  94         pm_prepare_console();
  95
  96         error = pm_notifier_call_chain(PM_SUSPEND_PREPARE);
  97         if (error)
  98                 goto Finish;
  99
 100         error = usermodehelper_disable();
 101         if (error)
 102                 goto Finish;
 103
 104         error = suspend_freeze_processes();
 105         if (!error)
 106                 return 0;
 107
 108         suspend_thaw_processes();
 109         usermodehelper_enable();
 110  Finish:
 111         pm_notifier_call_chain(PM_POST_SUSPEND);
 112         pm_restore_console();
 113         return error;
 114 }
 115
 116 /* default implementation */
 117 void __attribute__ ((weak)) arch_suspend_disable_irqs(void)
 118 {
 119         local_irq_disable();
 120 }
 121
 122 /* default implementation */
 123 void __attribute__ ((weak)) arch_suspend_enable_irqs(void)
 124 {
 125         local_irq_enable();
 126 }
 127
 128 /**
 129  * suspend_enter - enter the desired system sleep state.
 130  * @state: State to enter
 131  * @wakeup: Returns information that suspend should not be entered again.
 132  *
 133  * This function should be called after devices have been suspended.
 134  */
 135 static int suspend_enter(suspend_state_t state, bool *wakeup)
 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                 *wakeup = pm_wakeup_pending();
 170                 if (!(suspend_test(TEST_CORE) || *wakeup)) {
 171                         error = suspend_ops->enter(state);
 172                         events_check_enabled = false;
 173                 }
 174                 syscore_resume();
 175         }
 176
 177         arch_suspend_enable_irqs();
 178         BUG_ON(irqs_disabled());
 179
 180  Enable_cpus:
 181         enable_nonboot_cpus();
 182
 183  Platform_wake:
 184         if (suspend_ops->wake)
 185                 suspend_ops->wake();
 186
 187         dpm_resume_noirq(PMSG_RESUME);
 188
 189  Platform_finish:
 190         if (suspend_ops->finish)
 191                 suspend_ops->finish();
 192
 193         return error;
 194 }
 195
 196 /**
 197  *      suspend_devices_and_enter - suspend devices and enter the desired system
 198  *                                  sleep state.
 199  *      @state:           state to enter
 200  */
 201 int suspend_devices_and_enter(suspend_state_t state)
 202 {
 203         int error;
 204         bool wakeup = false;
 205
 206         if (!suspend_ops)
 207                 return -ENOSYS;
 208
 209         trace_machine_suspend(state);
 210         if (suspend_ops->begin) {
 211                 error = suspend_ops->begin(state);
 212                 if (error)
 213                         goto Close;
 214         }
 215         suspend_console();
 216         suspend_test_start();
 217         error = dpm_suspend_start(PMSG_SUSPEND);
 218         if (error) {
 219                 printk(KERN_ERR "PM: Some devices failed to suspend\n");
 220                 goto Recover_platform;
 221         }
 222         suspend_test_finish("suspend devices");
 223         if (suspend_test(TEST_DEVICES))
 224                 goto Recover_platform;
 225
 226         do {
 227                 error = suspend_enter(state, &wakeup);
 228         } while (!error && !wakeup
 229                 && suspend_ops->suspend_again && suspend_ops->suspend_again());
 230
 231  Resume_devices:
 232         suspend_test_start();
 233         dpm_resume_end(PMSG_RESUME);
 234         suspend_test_finish("resume devices");
 235         resume_console();
 236  Close:
 237         if (suspend_ops->end)
 238                 suspend_ops->end();
 239         trace_machine_suspend(PWR_EVENT_EXIT);
 240         return error;
 241
 242  Recover_platform:
 243         if (suspend_ops->recover)
 244                 suspend_ops->recover();
 245         goto Resume_devices;
 246 }
 247
 248 /**
 249  *      suspend_finish - Do final work before exiting suspend sequence.
 250  *
 251  *      Call platform code to clean up, restart processes, and free the
 252  *      console that we've allocated. This is not called for suspend-to-disk.
 253  */
 254 static void suspend_finish(void)
 255 {
 256         suspend_thaw_processes();
 257         usermodehelper_enable();
 258         pm_notifier_call_chain(PM_POST_SUSPEND);
 259         pm_restore_console();
 260 }
 261
 262 /**
 263  *      enter_state - Do common work of entering low-power state.
 264  *      @state:         pm_state structure for state we're entering.
 265  *
 266  *      Make sure we're the only ones trying to enter a sleep state. Fail
 267  *      if someone has beat us to it, since we don't want anything weird to
 268  *      happen when we wake up.
 269  *      Then, do the setup for suspend, enter the state, and cleaup (after
 270  *      we've woken up).
 271  */
 272 int enter_state(suspend_state_t state)
 273 {
 274         int error;
 275
 276         if (!valid_state(state))
 277                 return -ENODEV;
 278
 279         if (!mutex_trylock(&pm_mutex))
 280                 return -EBUSY;
 281
 282         printk(KERN_INFO "PM: Syncing filesystems ... ");
 283         sys_sync();
 284         printk("done.\n");
 285
 286         pr_debug("PM: Preparing system for %s sleep\n", pm_states[state]);
 287         error = suspend_prepare();
 288         if (error)
 289                 goto Unlock;
 290
 291         if (suspend_test(TEST_FREEZER))
 292                 goto Finish;
 293
 294         pr_debug("PM: Entering %s sleep\n", pm_states[state]);
 295         pm_restrict_gfp_mask();
 296         error = suspend_devices_and_enter(state);
 297         pm_restore_gfp_mask();
 298
 299  Finish:
 300         pr_debug("PM: Finishing wakeup.\n");
 301         suspend_finish();
 302  Unlock:
 303         mutex_unlock(&pm_mutex);
 304         return error;
 305 }
 306
 307 /**
 308  *      pm_suspend - Externally visible function for suspending system.
 309  *      @state:         Enumerated value of state to enter.
 310  *
 311  *      Determine whether or not value is within range, get state
 312  *      structure, and enter (above).
 313  */
 314 int pm_suspend(suspend_state_t state)
 315 {
 316         if (state > PM_SUSPEND_ON && state <= PM_SUSPEND_MAX)
 317                 return enter_state(state);
 318         return -EINVAL;
 319 }
 320 EXPORT_SYMBOL(pm_suspend);