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/kmod.h>
  16 #include <linux/console.h>
  17 #include <linux/cpu.h>
  18 #include <linux/syscalls.h>
  19 #include <linux/gfp.h>
  20 #include <linux/io.h>
  21 #include <linux/kernel.h>
  22 #include <linux/list.h>
  23 #include <linux/mm.h>
  24 #include <linux/slab.h>
  25 #include <linux/export.h>
  26 #include <linux/suspend.h>
  27 #include <linux/syscore_ops.h>
  28 #include <trace/events/power.h>
  29
  30 #include "power.h"
  31
  32 const char *const pm_states[PM_SUSPEND_MAX] = {
  33         [PM_SUSPEND_STANDBY]    = "standby",
  34         [PM_SUSPEND_MEM]        = "mem",
  35 };
  36
  37 static const struct platform_suspend_ops *suspend_ops;
  38
  39 /**
  40  *      suspend_set_ops - Set the global suspend method table.
  41  *      @ops:   Pointer to ops structure.
  42  */
  43 void suspend_set_ops(const struct platform_suspend_ops *ops)
  44 {
  45         mutex_lock(&pm_mutex);
  46         suspend_ops = ops;
  47         mutex_unlock(&pm_mutex);
  48 }
  49 EXPORT_SYMBOL_GPL(suspend_set_ops);
  50
  51 bool valid_state(suspend_state_t state)
  52 {
  53         /*
  54          * All states need lowlevel support and need to be valid to the lowlevel
  55          * implementation, no valid callback implies that none are valid.
  56          */
  57         return suspend_ops && suspend_ops->valid && suspend_ops->valid(state);
  58 }
  59
  60 /**
  61  * suspend_valid_only_mem - generic memory-only valid callback
  62  *
  63  * Platform drivers that implement mem suspend only and only need
  64  * to check for that in their .valid callback can use this instead
  65  * of rolling their own .valid callback.
  66  */
  67 int suspend_valid_only_mem(suspend_state_t state)
  68 {
  69         return state == PM_SUSPEND_MEM;
  70 }
  71 EXPORT_SYMBOL_GPL(suspend_valid_only_mem);
  72
  73 static int suspend_test(int level)
  74 {
  75 #ifdef CONFIG_PM_DEBUG
  76         if (pm_test_level == level) {
  77                 printk(KERN_INFO "suspend debug: Waiting for 5 seconds.\n");
  78                 mdelay(5000);
  79                 return 1;
  80         }
  81 #endif /* !CONFIG_PM_DEBUG */
  82         return 0;
  83 }
  84
  85 /**
  86  *      suspend_prepare - Do prep work before entering low-power state.
  87  *
  88  *      This is common code that is called for each state that we're entering.
  89  *      Run suspend notifiers, allocate a console and stop all processes.
  90  */
  91 static int suspend_prepare(void)
  92 {
  93         int error;
  94
  95         if (!suspend_ops || !suspend_ops->enter)
  96                 return -EPERM;
  97
  98         pm_prepare_console();
  99
 100         error = pm_notifier_call_chain(PM_SUSPEND_PREPARE);
 101         if (error)
 102                 goto Finish;
 103
 104         error = usermodehelper_disable();
 105         if (error)
 106                 goto Finish;
 107
 108         error = suspend_freeze_processes();
 109         if (error) {
 110                 suspend_stats.failed_freeze++;
 111                 dpm_save_failed_step(SUSPEND_FREEZE);
 112         } else
 113                 return 0;
 114
 115         suspend_thaw_processes();
 116         usermodehelper_enable();
 117  Finish:
 118         pm_notifier_call_chain(PM_POST_SUSPEND);
 119         pm_restore_console();
 120         return error;
 121 }
 122
 123 /* default implementation */
 124 void __attribute__ ((weak)) arch_suspend_disable_irqs(void)
 125 {
 126         local_irq_disable();
 127 }
 128
 129 /* default implementation */
 130 void __attribute__ ((weak)) arch_suspend_enable_irqs(void)
 131 {
 132         local_irq_enable();
 133 }
 134
 135 /**
 136  * suspend_enter - enter the desired system sleep state.
 137  * @state: State to enter
 138  * @wakeup: Returns information that suspend should not be entered again.
 139  *
 140  * This function should be called after devices have been suspended.
 141  */
 142 static int suspend_enter(suspend_state_t state, bool *wakeup)
 143 {
 144         int error;
 145
 146         if (suspend_ops->prepare) {
 147                 error = suspend_ops->prepare();
 148                 if (error)
 149                         goto Platform_finish;
 150         }
 151
 152         error = dpm_suspend_noirq(PMSG_SUSPEND);
 153         if (error) {
 154                 printk(KERN_ERR "PM: Some devices failed to power down\n");
 155                 goto Platform_finish;
 156         }
 157
 158         if (suspend_ops->prepare_late) {
 159                 error = suspend_ops->prepare_late();
 160                 if (error)
 161                         goto Platform_wake;
 162         }
 163
 164         if (suspend_test(TEST_PLATFORM))
 165                 goto Platform_wake;
 166
 167         error = disable_nonboot_cpus();
 168         if (error || suspend_test(TEST_CPUS))
 169                 goto Enable_cpus;
 170
 171         arch_suspend_disable_irqs();
 172         BUG_ON(!irqs_disabled());
 173
 174         error = syscore_suspend();
 175         if (!error) {
 176                 *wakeup = pm_wakeup_pending();
 177                 if (!(suspend_test(TEST_CORE) || *wakeup)) {
 178                         error = suspend_ops->enter(state);
 179                         events_check_enabled = false;
 180                 }
 181                 syscore_resume();
 182         }
 183
 184         arch_suspend_enable_irqs();
 185         BUG_ON(irqs_disabled());
 186
 187  Enable_cpus:
 188         enable_nonboot_cpus();
 189
 190  Platform_wake:
 191         if (suspend_ops->wake)
 192                 suspend_ops->wake();
 193
 194         dpm_resume_noirq(PMSG_RESUME);
 195
 196  Platform_finish:
 197         if (suspend_ops->finish)
 198                 suspend_ops->finish();
 199
 200         return error;
 201 }
 202
 203 /**
 204  *      suspend_devices_and_enter - suspend devices and enter the desired system
 205  *                                  sleep state.
 206  *      @state:           state to enter
 207  */
 208 int suspend_devices_and_enter(suspend_state_t state)
 209 {
 210         int error;
 211         bool wakeup = false;
 212
 213         if (!suspend_ops)
 214                 return -ENOSYS;
 215
 216         trace_machine_suspend(state);
 217         if (suspend_ops->begin) {
 218                 error = suspend_ops->begin(state);
 219                 if (error)
 220                         goto Close;
 221         }
 222         suspend_console();
 223         suspend_test_start();
 224         error = dpm_suspend_start(PMSG_SUSPEND);
 225         if (error) {
 226                 printk(KERN_ERR "PM: Some devices failed to suspend\n");
 227                 goto Recover_platform;
 228         }
 229         suspend_test_finish("suspend devices");
 230         if (suspend_test(TEST_DEVICES))
 231                 goto Recover_platform;
 232
 233         do {
 234                 error = suspend_enter(state, &wakeup);
 235         } while (!error && !wakeup
 236                 && suspend_ops->suspend_again && suspend_ops->suspend_again());
 237
 238  Resume_devices:
 239         suspend_test_start();
 240         dpm_resume_end(PMSG_RESUME);
 241         suspend_test_finish("resume devices");
 242         resume_console();
 243  Close:
 244         if (suspend_ops->end)
 245                 suspend_ops->end();
 246         trace_machine_suspend(PWR_EVENT_EXIT);
 247         return error;
 248
 249  Recover_platform:
 250         if (suspend_ops->recover)
 251                 suspend_ops->recover();
 252         goto Resume_devices;
 253 }
 254
 255 /**
 256  *      suspend_finish - Do final work before exiting suspend sequence.
 257  *
 258  *      Call platform code to clean up, restart processes, and free the
 259  *      console that we've allocated. This is not called for suspend-to-disk.
 260  */
 261 static void suspend_finish(void)
 262 {
 263         suspend_thaw_processes();
 264         usermodehelper_enable();
 265         pm_notifier_call_chain(PM_POST_SUSPEND);
 266         pm_restore_console();
 267 }
 268
 269 /**
 270  *      enter_state - Do common work of entering low-power state.
 271  *      @state:         pm_state structure for state we're entering.
 272  *
 273  *      Make sure we're the only ones trying to enter a sleep state. Fail
 274  *      if someone has beat us to it, since we don't want anything weird to
 275  *      happen when we wake up.
 276  *      Then, do the setup for suspend, enter the state, and cleaup (after
 277  *      we've woken up).
 278  */
 279 int enter_state(suspend_state_t state)
 280 {
 281         int error;
 282
 283         if (!valid_state(state))
 284                 return -ENODEV;
 285
 286         if (!mutex_trylock(&pm_mutex))
 287                 return -EBUSY;
 288
 289         printk(KERN_INFO "PM: Syncing filesystems ... ");
 290         sys_sync();
 291         printk("done.\n");
 292
 293         pr_debug("PM: Preparing system for %s sleep\n", pm_states[state]);
 294         error = suspend_prepare();
 295         if (error)
 296                 goto Unlock;
 297
 298         if (suspend_test(TEST_FREEZER))
 299                 goto Finish;
 300
 301         pr_debug("PM: Entering %s sleep\n", pm_states[state]);
 302         pm_restrict_gfp_mask();
 303         error = suspend_devices_and_enter(state);
 304         pm_restore_gfp_mask();
 305
 306  Finish:
 307         pr_debug("PM: Finishing wakeup.\n");
 308         suspend_finish();
 309  Unlock:
 310         mutex_unlock(&pm_mutex);
 311         return error;
 312 }
 313
 314 /**
 315  *      pm_suspend - Externally visible function for suspending system.
 316  *      @state:         Enumerated value of state to enter.
 317  *
 318  *      Determine whether or not value is within range, get state
 319  *      structure, and enter (above).
 320  */
 321 int pm_suspend(suspend_state_t state)
 322 {
 323         int ret;
 324         if (state > PM_SUSPEND_ON && state < PM_SUSPEND_MAX) {
 325                 ret = enter_state(state);
 326                 if (ret) {
 327                         suspend_stats.fail++;
 328                         dpm_save_failed_errno(ret);
 329                 } else
 330                         suspend_stats.success++;
 331                 return ret;
 332         }
 333         return -EINVAL;
 334 }
 335 EXPORT_SYMBOL(pm_suspend);