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 <linux/rtc.h>
  29 #include <trace/events/power.h>
  30 #include <linux/wakeup_reason.h>
  31
  32 #include "power.h"
  33
  34 const char *const pm_states[PM_SUSPEND_MAX] = {
  35         [PM_SUSPEND_FREEZE]     = "freeze",
  36         [PM_SUSPEND_STANDBY]    = "standby",
  37         [PM_SUSPEND_MEM]        = "mem",
  38 };
  39
  40 static const struct platform_suspend_ops *suspend_ops;
  41
  42 static bool need_suspend_ops(suspend_state_t state)
  43 {
  44         return !!(state > PM_SUSPEND_FREEZE);
  45 }
  46
  47 static DECLARE_WAIT_QUEUE_HEAD(suspend_freeze_wait_head);
  48 static bool suspend_freeze_wake;
  49
  50 static void freeze_begin(void)
  51 {
  52         suspend_freeze_wake = false;
  53 }
  54
  55 static void freeze_enter(void)
  56 {
  57         wait_event(suspend_freeze_wait_head, suspend_freeze_wake);
  58 }
  59
  60 void freeze_wake(void)
  61 {
  62         suspend_freeze_wake = true;
  63         wake_up(&suspend_freeze_wait_head);
  64 }
  65 EXPORT_SYMBOL_GPL(freeze_wake);
  66
  67 /**
  68  * suspend_set_ops - Set the global suspend method table.
  69  * @ops: Suspend operations to use.
  70  */
  71 void suspend_set_ops(const struct platform_suspend_ops *ops)
  72 {
  73         lock_system_sleep();
  74         suspend_ops = ops;
  75         unlock_system_sleep();
  76 }
  77 EXPORT_SYMBOL_GPL(suspend_set_ops);
  78
  79 bool valid_state(suspend_state_t state)
  80 {
  81         if (state == PM_SUSPEND_FREEZE) {
  82 #ifdef CONFIG_PM_DEBUG
  83                 if (pm_test_level != TEST_NONE &&
  84                     pm_test_level != TEST_FREEZER &&
  85                     pm_test_level != TEST_DEVICES &&
  86                     pm_test_level != TEST_PLATFORM) {
  87                         printk(KERN_WARNING "Unsupported pm_test mode for "
  88                                         "freeze state, please choose "
  89                                         "none/freezer/devices/platform.\n");
  90                         return false;
  91                 }
  92 #endif
  93                         return true;
  94         }
  95         /*
  96          * PM_SUSPEND_STANDBY and PM_SUSPEND_MEMORY states need lowlevel
  97          * support and need to be valid to the lowlevel
  98          * implementation, no valid callback implies that none are valid.
  99          */
 100         return suspend_ops && suspend_ops->valid && suspend_ops->valid(state);
 101 }
 102
 103 /**
 104  * suspend_valid_only_mem - Generic memory-only valid callback.
 105  *
 106  * Platform drivers that implement mem suspend only and only need to check for
 107  * that in their .valid() callback can use this instead of rolling their own
 108  * .valid() callback.
 109  */
 110 int suspend_valid_only_mem(suspend_state_t state)
 111 {
 112         return state == PM_SUSPEND_MEM;
 113 }
 114 EXPORT_SYMBOL_GPL(suspend_valid_only_mem);
 115
 116 static int suspend_test(int level)
 117 {
 118 #ifdef CONFIG_PM_DEBUG
 119         if (pm_test_level == level) {
 120                 printk(KERN_INFO "suspend debug: Waiting for 5 seconds.\n");
 121                 mdelay(5000);
 122                 return 1;
 123         }
 124 #endif /* !CONFIG_PM_DEBUG */
 125         return 0;
 126 }
 127
 128 /**
 129  * suspend_prepare - Prepare for entering system sleep state.
 130  *
 131  * Common code run for every system sleep state that can be entered (except for
 132  * hibernation).  Run suspend notifiers, allocate the "suspend" console and
 133  * freeze processes.
 134  */
 135 static int suspend_prepare(suspend_state_t state)
 136 {
 137         int error;
 138
 139         if (need_suspend_ops(state) && (!suspend_ops || !suspend_ops->enter))
 140                 return -EPERM;
 141
 142         pm_prepare_console();
 143
 144         error = pm_notifier_call_chain(PM_SUSPEND_PREPARE);
 145         if (error)
 146                 goto Finish;
 147
 148         error = suspend_freeze_processes();
 149         if (!error)
 150                 return 0;
 151         log_suspend_abort_reason("One or more tasks refusing to freeze");
 152         suspend_stats.failed_freeze++;
 153         dpm_save_failed_step(SUSPEND_FREEZE);
 154  Finish:
 155         pm_notifier_call_chain(PM_POST_SUSPEND);
 156         pm_restore_console();
 157         return error;
 158 }
 159
 160 /* default implementation */
 161 void __attribute__ ((weak)) arch_suspend_disable_irqs(void)
 162 {
 163         local_irq_disable();
 164 }
 165
 166 /* default implementation */
 167 void __attribute__ ((weak)) arch_suspend_enable_irqs(void)
 168 {
 169         local_irq_enable();
 170 }
 171
 172 /**
 173  * suspend_enter - Make the system enter the given sleep state.
 174  * @state: System sleep state to enter.
 175  * @wakeup: Returns information that the sleep state should not be re-entered.
 176  *
 177  * This function should be called after devices have been suspended.
 178  */
 179 static int suspend_enter(suspend_state_t state, bool *wakeup)
 180 {
 181         char suspend_abort[MAX_SUSPEND_ABORT_LEN];
 182         int error, last_dev;
 183
 184         if (need_suspend_ops(state) && suspend_ops->prepare) {
 185                 error = suspend_ops->prepare();
 186                 if (error)
 187                         goto Platform_finish;
 188         }
 189
 190         error = dpm_suspend_end(PMSG_SUSPEND);
 191         if (error) {
 192                 last_dev = suspend_stats.last_failed_dev + REC_FAILED_NUM - 1;
 193                 last_dev %= REC_FAILED_NUM;
 194                 printk(KERN_ERR "PM: Some devices failed to power down\n");
 195                 log_suspend_abort_reason("%s device failed to power down",
 196                         suspend_stats.failed_devs[last_dev]);
 197                 goto Platform_finish;
 198         }
 199
 200         if (need_suspend_ops(state) && suspend_ops->prepare_late) {
 201                 error = suspend_ops->prepare_late();
 202                 if (error)
 203                         goto Platform_wake;
 204         }
 205
 206         if (suspend_test(TEST_PLATFORM))
 207                 goto Platform_wake;
 208
 209         /*
 210          * PM_SUSPEND_FREEZE equals
 211          * frozen processes + suspended devices + idle processors.
 212          * Thus we should invoke freeze_enter() soon after
 213          * all the devices are suspended.
 214          */
 215         if (state == PM_SUSPEND_FREEZE) {
 216                 freeze_enter();
 217                 goto Platform_wake;
 218         }
 219
 220         error = disable_nonboot_cpus();
 221         if (error || suspend_test(TEST_CPUS)) {
 222                 log_suspend_abort_reason("Disabling non-boot cpus failed");
 223                 goto Enable_cpus;
 224         }
 225
 226         arch_suspend_disable_irqs();
 227         BUG_ON(!irqs_disabled());
 228
 229         error = syscore_suspend();
 230         if (!error) {
 231                 *wakeup = pm_wakeup_pending();
 232                 if (!(suspend_test(TEST_CORE) || *wakeup)) {
 233                         error = suspend_ops->enter(state);
 234                         events_check_enabled = false;
 235                 } else {
 236                         pm_get_active_wakeup_sources(suspend_abort,
 237                                 MAX_SUSPEND_ABORT_LEN);
 238                         log_suspend_abort_reason(suspend_abort);
 239                 }
 240                 syscore_resume();
 241         }
 242
 243         arch_suspend_enable_irqs();
 244         BUG_ON(irqs_disabled());
 245
 246  Enable_cpus:
 247         enable_nonboot_cpus();
 248
 249  Platform_wake:
 250         if (need_suspend_ops(state) && suspend_ops->wake)
 251                 suspend_ops->wake();
 252
 253         dpm_resume_start(PMSG_RESUME);
 254
 255  Platform_finish:
 256         if (need_suspend_ops(state) && suspend_ops->finish)
 257                 suspend_ops->finish();
 258
 259         return error;
 260 }
 261
 262 /**
 263  * suspend_devices_and_enter - Suspend devices and enter system sleep state.
 264  * @state: System sleep state to enter.
 265  */
 266 int suspend_devices_and_enter(suspend_state_t state)
 267 {
 268         int error;
 269         bool wakeup = false;
 270
 271         if (need_suspend_ops(state) && !suspend_ops)
 272                 return -ENOSYS;
 273
 274         trace_machine_suspend(state);
 275         if (need_suspend_ops(state) && suspend_ops->begin) {
 276                 error = suspend_ops->begin(state);
 277                 if (error)
 278                         goto Close;
 279         }
 280         suspend_console();
 281         ftrace_stop();
 282         suspend_test_start();
 283         error = dpm_suspend_start(PMSG_SUSPEND);
 284         if (error) {
 285                 printk(KERN_ERR "PM: Some devices failed to suspend\n");
 286                 log_suspend_abort_reason("Some devices failed to suspend");
 287                 goto Recover_platform;
 288         }
 289         suspend_test_finish("suspend devices");
 290         if (suspend_test(TEST_DEVICES))
 291                 goto Recover_platform;
 292
 293         do {
 294                 error = suspend_enter(state, &wakeup);
 295         } while (!error && !wakeup && need_suspend_ops(state)
 296                 && suspend_ops->suspend_again && suspend_ops->suspend_again());
 297
 298  Resume_devices:
 299         suspend_test_start();
 300         dpm_resume_end(PMSG_RESUME);
 301         suspend_test_finish("resume devices");
 302         ftrace_start();
 303         resume_console();
 304  Close:
 305         if (need_suspend_ops(state) && suspend_ops->end)
 306                 suspend_ops->end();
 307         trace_machine_suspend(PWR_EVENT_EXIT);
 308         return error;
 309
 310  Recover_platform:
 311         if (need_suspend_ops(state) && suspend_ops->recover)
 312                 suspend_ops->recover();
 313         goto Resume_devices;
 314 }
 315
 316 /**
 317  * suspend_finish - Clean up before finishing the suspend sequence.
 318  *
 319  * Call platform code to clean up, restart processes, and free the console that
 320  * we've allocated. This routine is not called for hibernation.
 321  */
 322 static void suspend_finish(void)
 323 {
 324         suspend_thaw_processes();
 325         pm_notifier_call_chain(PM_POST_SUSPEND);
 326         pm_restore_console();
 327 }
 328
 329 /**
 330  * enter_state - Do common work needed to enter system sleep state.
 331  * @state: System sleep state to enter.
 332  *
 333  * Make sure that no one else is trying to put the system into a sleep state.
 334  * Fail if that's not the case.  Otherwise, prepare for system suspend, make the
 335  * system enter the given sleep state and clean up after wakeup.
 336  */
 337 static int enter_state(suspend_state_t state)
 338 {
 339         int error;
 340
 341         if (!valid_state(state))
 342                 return -ENODEV;
 343
 344         if (!mutex_trylock(&pm_mutex))
 345                 return -EBUSY;
 346
 347         if (state == PM_SUSPEND_FREEZE)
 348                 freeze_begin();
 349
 350         printk(KERN_INFO "PM: Syncing filesystems ... ");
 351         sys_sync();
 352         printk("done.\n");
 353
 354         pr_debug("PM: Preparing system for %s sleep\n", pm_states[state]);
 355         error = suspend_prepare(state);
 356         if (error)
 357                 goto Unlock;
 358
 359         if (suspend_test(TEST_FREEZER))
 360                 goto Finish;
 361
 362         pr_debug("PM: Entering %s sleep\n", pm_states[state]);
 363         pm_restrict_gfp_mask();
 364         error = suspend_devices_and_enter(state);
 365         pm_restore_gfp_mask();
 366
 367  Finish:
 368         pr_debug("PM: Finishing wakeup.\n");
 369         suspend_finish();
 370  Unlock:
 371         mutex_unlock(&pm_mutex);
 372         return error;
 373 }
 374
 375 static void pm_suspend_marker(char *annotation)
 376 {
 377         struct timespec ts;
 378         struct rtc_time tm;
 379
 380         getnstimeofday(&ts);
 381         rtc_time_to_tm(ts.tv_sec, &tm);
 382         pr_info("PM: suspend %s %d-%02d-%02d %02d:%02d:%02d.%09lu UTC\n",
 383                 annotation, tm.tm_year + 1900, tm.tm_mon + 1, tm.tm_mday,
 384                 tm.tm_hour, tm.tm_min, tm.tm_sec, ts.tv_nsec);
 385 }
 386
 387 /**
 388  * pm_suspend - Externally visible function for suspending the system.
 389  * @state: System sleep state to enter.
 390  *
 391  * Check if the value of @state represents one of the supported states,
 392  * execute enter_state() and update system suspend statistics.
 393  */
 394 int pm_suspend(suspend_state_t state)
 395 {
 396         int error;
 397
 398         if (state <= PM_SUSPEND_ON || state >= PM_SUSPEND_MAX)
 399                 return -EINVAL;
 400
 401         pm_suspend_marker("entry");
 402         error = enter_state(state);
 403         if (error) {
 404                 suspend_stats.fail++;
 405                 dpm_save_failed_errno(error);
 406         } else {
 407                 suspend_stats.success++;
 408         }
 409         pm_suspend_marker("exit");
 410         return error;
 411 }
 412 EXPORT_SYMBOL(pm_suspend);