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/export.h>
  25 #include <linux/suspend.h>
  26 #include <linux/syscore_ops.h>
  27 #include <linux/ftrace.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_FREEZE]     = "freeze",
  34         [PM_SUSPEND_STANDBY]    = "standby",
  35         [PM_SUSPEND_MEM]        = "mem",
  36 };
  37
  38 static const struct platform_suspend_ops *suspend_ops;
  39
  40 static bool need_suspend_ops(suspend_state_t state)
  41 {
  42         return !!(state > PM_SUSPEND_FREEZE);
  43 }
  44
  45 static DECLARE_WAIT_QUEUE_HEAD(suspend_freeze_wait_head);
  46 static bool suspend_freeze_wake;
  47
  48 static void freeze_begin(void)
  49 {
  50         suspend_freeze_wake = false;
  51 }
  52
  53 static void freeze_enter(void)
  54 {
  55         wait_event(suspend_freeze_wait_head, suspend_freeze_wake);
  56 }
  57
  58 void freeze_wake(void)
  59 {
  60         suspend_freeze_wake = true;
  61         wake_up(&suspend_freeze_wait_head);
  62 }
  63 EXPORT_SYMBOL_GPL(freeze_wake);
  64
  65 /**
  66  * suspend_set_ops - Set the global suspend method table.
  67  * @ops: Suspend operations to use.
  68  */
  69 void suspend_set_ops(const struct platform_suspend_ops *ops)
  70 {
  71         lock_system_sleep();
  72         suspend_ops = ops;
  73         unlock_system_sleep();
  74 }
  75 EXPORT_SYMBOL_GPL(suspend_set_ops);
  76
  77 bool valid_state(suspend_state_t state)
  78 {
  79         if (state == PM_SUSPEND_FREEZE) {
  80 #ifdef CONFIG_PM_DEBUG
  81                 if (pm_test_level != TEST_NONE &&
  82                     pm_test_level != TEST_FREEZER &&
  83                     pm_test_level != TEST_DEVICES &&
  84                     pm_test_level != TEST_PLATFORM) {
  85                         printk(KERN_WARNING "Unsupported pm_test mode for "
  86                                         "freeze state, please choose "
  87                                         "none/freezer/devices/platform.\n");
  88                         return false;
  89                 }
  90 #endif
  91                         return true;
  92         }
  93         /*
  94          * PM_SUSPEND_STANDBY and PM_SUSPEND_MEMORY states need lowlevel
  95          * support and need to be valid to the lowlevel
  96          * implementation, no valid callback implies that none are valid.
  97          */
  98         return suspend_ops && suspend_ops->valid && suspend_ops->valid(state);
  99 }
 100
 101 /**
 102  * suspend_valid_only_mem - Generic memory-only valid callback.
 103  *
 104  * Platform drivers that implement mem suspend only and only need to check for
 105  * that in their .valid() callback can use this instead of rolling their own
 106  * .valid() callback.
 107  */
 108 int suspend_valid_only_mem(suspend_state_t state)
 109 {
 110         return state == PM_SUSPEND_MEM;
 111 }
 112 EXPORT_SYMBOL_GPL(suspend_valid_only_mem);
 113
 114 static int suspend_test(int level)
 115 {
 116 #ifdef CONFIG_PM_DEBUG
 117         if (pm_test_level == level) {
 118                 printk(KERN_INFO "suspend debug: Waiting for 5 seconds.\n");
 119                 mdelay(5000);
 120                 return 1;
 121         }
 122 #endif /* !CONFIG_PM_DEBUG */
 123         return 0;
 124 }
 125
 126 /**
 127  * suspend_prepare - Prepare for entering system sleep state.
 128  *
 129  * Common code run for every system sleep state that can be entered (except for
 130  * hibernation).  Run suspend notifiers, allocate the "suspend" console and
 131  * freeze processes.
 132  */
 133 static int suspend_prepare(suspend_state_t state)
 134 {
 135         int error;
 136
 137         if (need_suspend_ops(state) && (!suspend_ops || !suspend_ops->enter))
 138                 return -EPERM;
 139
 140         pm_prepare_console();
 141
 142         error = pm_notifier_call_chain(PM_SUSPEND_PREPARE);
 143         if (error)
 144                 goto Finish;
 145
 146         error = suspend_freeze_processes();
 147         if (!error)
 148                 return 0;
 149
 150         suspend_stats.failed_freeze++;
 151         dpm_save_failed_step(SUSPEND_FREEZE);
 152  Finish:
 153         pm_notifier_call_chain(PM_POST_SUSPEND);
 154         pm_restore_console();
 155         return error;
 156 }
 157
 158 /* default implementation */
 159 void __attribute__ ((weak)) arch_suspend_disable_irqs(void)
 160 {
 161         local_irq_disable();
 162 }
 163
 164 /* default implementation */
 165 void __attribute__ ((weak)) arch_suspend_enable_irqs(void)
 166 {
 167         local_irq_enable();
 168 }
 169
 170 /**
 171  * suspend_enter - Make the system enter the given sleep state.
 172  * @state: System sleep state to enter.
 173  * @wakeup: Returns information that the sleep state should not be re-entered.
 174  *
 175  * This function should be called after devices have been suspended.
 176  */
 177 static int suspend_enter(suspend_state_t state, bool *wakeup)
 178 {
 179         int error;
 180
 181         if (need_suspend_ops(state) && suspend_ops->prepare) {
 182                 error = suspend_ops->prepare();
 183                 if (error)
 184                         goto Platform_finish;
 185         }
 186
 187         error = dpm_suspend_end(PMSG_SUSPEND);
 188         if (error) {
 189                 printk(KERN_ERR "PM: Some devices failed to power down\n");
 190                 goto Platform_finish;
 191         }
 192
 193         if (need_suspend_ops(state) && suspend_ops->prepare_late) {
 194                 error = suspend_ops->prepare_late();
 195                 if (error)
 196                         goto Platform_wake;
 197         }
 198
 199         if (suspend_test(TEST_PLATFORM))
 200                 goto Platform_wake;
 201
 202         /*
 203          * PM_SUSPEND_FREEZE equals
 204          * frozen processes + suspended devices + idle processors.
 205          * Thus we should invoke freeze_enter() soon after
 206          * all the devices are suspended.
 207          */
 208         if (state == PM_SUSPEND_FREEZE) {
 209                 freeze_enter();
 210                 goto Platform_wake;
 211         }
 212
 213         ftrace_stop();
 214         error = disable_nonboot_cpus();
 215         if (error || suspend_test(TEST_CPUS))
 216                 goto Enable_cpus;
 217
 218         arch_suspend_disable_irqs();
 219         BUG_ON(!irqs_disabled());
 220
 221         error = syscore_suspend();
 222         if (!error) {
 223                 *wakeup = pm_wakeup_pending();
 224                 if (!(suspend_test(TEST_CORE) || *wakeup)) {
 225                         error = suspend_ops->enter(state);
 226                         events_check_enabled = false;
 227                 }
 228                 syscore_resume();
 229         }
 230
 231         arch_suspend_enable_irqs();
 232         BUG_ON(irqs_disabled());
 233
 234  Enable_cpus:
 235         enable_nonboot_cpus();
 236         ftrace_start();
 237
 238  Platform_wake:
 239         if (need_suspend_ops(state) && suspend_ops->wake)
 240                 suspend_ops->wake();
 241
 242         dpm_resume_start(PMSG_RESUME);
 243
 244  Platform_finish:
 245         if (need_suspend_ops(state) && suspend_ops->finish)
 246                 suspend_ops->finish();
 247
 248         return error;
 249 }
 250
 251 /**
 252  * suspend_devices_and_enter - Suspend devices and enter system sleep state.
 253  * @state: System sleep state to enter.
 254  */
 255 int suspend_devices_and_enter(suspend_state_t state)
 256 {
 257         int error;
 258         bool wakeup = false;
 259
 260         if (need_suspend_ops(state) && !suspend_ops)
 261                 return -ENOSYS;
 262
 263         trace_machine_suspend(state);
 264         if (need_suspend_ops(state) && suspend_ops->begin) {
 265                 error = suspend_ops->begin(state);
 266                 if (error)
 267                         goto Close;
 268         }
 269         suspend_console();
 270         suspend_test_start();
 271         error = dpm_suspend_start(PMSG_SUSPEND);
 272         if (error) {
 273                 pr_err("PM: Some devices failed to suspend, or early wake event detected\n");
 274                 goto Recover_platform;
 275         }
 276         suspend_test_finish("suspend devices");
 277         if (suspend_test(TEST_DEVICES))
 278                 goto Recover_platform;
 279
 280         do {
 281                 error = suspend_enter(state, &wakeup);
 282         } while (!error && !wakeup && need_suspend_ops(state)
 283                 && suspend_ops->suspend_again && suspend_ops->suspend_again());
 284
 285  Resume_devices:
 286         suspend_test_start();
 287         dpm_resume_end(PMSG_RESUME);
 288         suspend_test_finish("resume devices");
 289         resume_console();
 290  Close:
 291         if (need_suspend_ops(state) && suspend_ops->end)
 292                 suspend_ops->end();
 293         trace_machine_suspend(PWR_EVENT_EXIT);
 294         return error;
 295
 296  Recover_platform:
 297         if (need_suspend_ops(state) && suspend_ops->recover)
 298                 suspend_ops->recover();
 299         goto Resume_devices;
 300 }
 301
 302 /**
 303  * suspend_finish - Clean up before finishing the suspend sequence.
 304  *
 305  * Call platform code to clean up, restart processes, and free the console that
 306  * we've allocated. This routine is not called for hibernation.
 307  */
 308 static void suspend_finish(void)
 309 {
 310         suspend_thaw_processes();
 311         pm_notifier_call_chain(PM_POST_SUSPEND);
 312         pm_restore_console();
 313 }
 314
 315 /**
 316  * enter_state - Do common work needed to enter system sleep state.
 317  * @state: System sleep state to enter.
 318  *
 319  * Make sure that no one else is trying to put the system into a sleep state.
 320  * Fail if that's not the case.  Otherwise, prepare for system suspend, make the
 321  * system enter the given sleep state and clean up after wakeup.
 322  */
 323 static int enter_state(suspend_state_t state)
 324 {
 325         int error;
 326
 327         if (!valid_state(state))
 328                 return -ENODEV;
 329
 330         if (!mutex_trylock(&pm_mutex))
 331                 return -EBUSY;
 332
 333         if (state == PM_SUSPEND_FREEZE)
 334                 freeze_begin();
 335
 336         printk(KERN_INFO "PM: Syncing filesystems ... ");
 337         sys_sync();
 338         printk("done.\n");
 339
 340         pr_debug("PM: Preparing system for %s sleep\n", pm_states[state]);
 341         error = suspend_prepare(state);
 342         if (error)
 343                 goto Unlock;
 344
 345         if (suspend_test(TEST_FREEZER))
 346                 goto Finish;
 347
 348         pr_debug("PM: Entering %s sleep\n", pm_states[state]);
 349         pm_restrict_gfp_mask();
 350         error = suspend_devices_and_enter(state);
 351         pm_restore_gfp_mask();
 352
 353  Finish:
 354         pr_debug("PM: Finishing wakeup.\n");
 355         suspend_finish();
 356  Unlock:
 357         mutex_unlock(&pm_mutex);
 358         return error;
 359 }
 360
 361 /**
 362  * pm_suspend - Externally visible function for suspending the system.
 363  * @state: System sleep state to enter.
 364  *
 365  * Check if the value of @state represents one of the supported states,
 366  * execute enter_state() and update system suspend statistics.
 367  */
 368 int pm_suspend(suspend_state_t state)
 369 {
 370         int error;
 371
 372         if (state <= PM_SUSPEND_ON || state >= PM_SUSPEND_MAX)
 373                 return -EINVAL;
 374
 375         error = enter_state(state);
 376         if (error) {
 377                 suspend_stats.fail++;
 378                 dpm_save_failed_errno(error);
 379         } else {
 380                 suspend_stats.success++;
 381         }
 382         return error;
 383 }
 384 EXPORT_SYMBOL(pm_suspend);