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 #ifdef CONFIG_EARLYSUSPEND
  32         [PM_SUSPEND_ON]         = "on",
  33 #elif defined(CONFIG_PARTIALSUSPEND_SLP)
  34         [PM_SUSPEND_ON]         = "post_resume",
  35 #endif
  36         [PM_SUSPEND_STANDBY]    = "standby",
  37         [PM_SUSPEND_MEM]        = "mem",
  38 #ifdef CONFIG_PARTIALSUSPEND_SLP
  39         [PM_SUSPEND_PRE]        = "pre_suspend"
  40 #endif
  41 };
  42
  43 static const struct platform_suspend_ops *suspend_ops;
  44
  45 /**
  46  *      suspend_set_ops - Set the global suspend method table.
  47  *      @ops:   Pointer to ops structure.
  48  */
  49 void suspend_set_ops(const struct platform_suspend_ops *ops)
  50 {
  51         mutex_lock(&pm_mutex);
  52         suspend_ops = ops;
  53         mutex_unlock(&pm_mutex);
  54 }
  55
  56 bool valid_state(suspend_state_t state)
  57 {
  58         /*
  59          * All states need lowlevel support and need to be valid to the lowlevel
  60          * implementation, no valid callback implies that none are valid.
  61          */
  62         return suspend_ops && suspend_ops->valid && suspend_ops->valid(state);
  63 }
  64
  65 /**
  66  * suspend_valid_only_mem - generic memory-only valid callback
  67  *
  68  * Platform drivers that implement mem suspend only and only need
  69  * to check for that in their .valid callback can use this instead
  70  * of rolling their own .valid callback.
  71  */
  72 int suspend_valid_only_mem(suspend_state_t state)
  73 {
  74         return state == PM_SUSPEND_MEM;
  75 }
  76
  77 #ifdef CONFIG_PARTIALSUSPEND_SLP
  78 int suspend_valid_partialsuspend(suspend_state_t state)
  79 {
  80         return ((state == PM_SUSPEND_MEM) || (state == PM_SUSPEND_PRE)
  81                 || (state == PM_SUSPEND_ON));
  82 }
  83 #endif
  84
  85 static int suspend_test(int level)
  86 {
  87 #ifdef CONFIG_PM_DEBUG
  88         if (pm_test_level == level) {
  89                 printk(KERN_INFO "suspend debug: Waiting for 5 seconds.\n");
  90                 mdelay(5000);
  91                 return 1;
  92         }
  93 #endif /* !CONFIG_PM_DEBUG */
  94         return 0;
  95 }
  96
  97 /**
  98  *      suspend_prepare - Do prep work before entering low-power state.
  99  *
 100  *      This is common code that is called for each state that we're entering.
 101  *      Run suspend notifiers, allocate a console and stop all processes.
 102  */
 103 static int suspend_prepare(void)
 104 {
 105         int error;
 106
 107         if (!suspend_ops || !suspend_ops->enter)
 108                 return -EPERM;
 109
 110         pm_prepare_console();
 111
 112         error = pm_notifier_call_chain(PM_SUSPEND_PREPARE);
 113         if (error)
 114                 goto Finish;
 115
 116         error = usermodehelper_disable();
 117         if (error)
 118                 goto Finish;
 119
 120         error = suspend_freeze_processes();
 121         if (!error)
 122                 return 0;
 123
 124         suspend_thaw_processes();
 125         usermodehelper_enable();
 126  Finish:
 127         pm_notifier_call_chain(PM_POST_SUSPEND);
 128         pm_restore_console();
 129         return error;
 130 }
 131
 132 /* default implementation */
 133 void __attribute__ ((weak)) arch_suspend_disable_irqs(void)
 134 {
 135         local_irq_disable();
 136 }
 137
 138 /* default implementation */
 139 void __attribute__ ((weak)) arch_suspend_enable_irqs(void)
 140 {
 141         local_irq_enable();
 142 }
 143
 144 #if !defined(CONFIG_CPU_EXYNOS4210)
 145 #define CHECK_POINT printk(KERN_DEBUG "%s:%d\n", __func__, __LINE__)
 146 #else
 147 #define CHECK_POINT
 148 #endif
 149
 150 /**
 151  * suspend_enter - enter the desired system sleep state.
 152  * @state: State to enter
 153  * @wakeup: Returns information that suspend should not be entered again.
 154  *
 155  * This function should be called after devices have been suspended.
 156  */
 157 static int suspend_enter(suspend_state_t state, bool *wakeup)
 158 {
 159         int error;
 160
 161         CHECK_POINT;
 162
 163         if (suspend_ops->prepare) {
 164                 error = suspend_ops->prepare();
 165                 if (error)
 166                         goto Platform_finish;
 167         }
 168
 169         CHECK_POINT;
 170
 171         error = dpm_suspend_noirq(PMSG_SUSPEND);
 172         if (error) {
 173                 printk(KERN_ERR "PM: Some devices failed to power down\n");
 174                 goto Platform_finish;
 175         }
 176
 177         CHECK_POINT;
 178
 179         if (suspend_ops->prepare_late) {
 180                 error = suspend_ops->prepare_late();
 181                 if (error)
 182                         goto Platform_wake;
 183         }
 184
 185         if (suspend_test(TEST_PLATFORM))
 186                 goto Platform_wake;
 187
 188         error = disable_nonboot_cpus();
 189         if (error || suspend_test(TEST_CPUS))
 190                 goto Enable_cpus;
 191
 192         CHECK_POINT;
 193
 194         arch_suspend_disable_irqs();
 195         BUG_ON(!irqs_disabled());
 196
 197         error = syscore_suspend();
 198
 199         CHECK_POINT;
 200
 201         if (!error) {
 202                 *wakeup = pm_wakeup_pending();
 203                 if (!(suspend_test(TEST_CORE) || *wakeup)) {
 204                         error = suspend_ops->enter(state);
 205                         events_check_enabled = false;
 206                 }
 207                 syscore_resume();
 208         }
 209
 210         arch_suspend_enable_irqs();
 211         BUG_ON(irqs_disabled());
 212
 213  Enable_cpus:
 214         enable_nonboot_cpus();
 215
 216  Platform_wake:
 217         if (suspend_ops->wake)
 218                 suspend_ops->wake();
 219
 220         dpm_resume_noirq(PMSG_RESUME);
 221
 222  Platform_finish:
 223         if (suspend_ops->finish)
 224                 suspend_ops->finish();
 225
 226         return error;
 227 }
 228
 229 /**
 230  *      suspend_devices_and_enter - suspend devices and enter the desired system
 231  *                                  sleep state.
 232  *      @state:           state to enter
 233  */
 234 int suspend_devices_and_enter(suspend_state_t state)
 235 {
 236         int error;
 237         bool wakeup = false;
 238
 239         if (!suspend_ops)
 240                 return -ENOSYS;
 241
 242         trace_machine_suspend(state);
 243         if (suspend_ops->begin) {
 244                 error = suspend_ops->begin(state);
 245                 if (error)
 246                         goto Close;
 247         }
 248         suspend_console();
 249         suspend_test_start();
 250         error = dpm_suspend_start(PMSG_SUSPEND);
 251         if (error) {
 252                 printk(KERN_ERR "PM: Some devices failed to suspend\n");
 253                 goto Recover_platform;
 254         }
 255         suspend_test_finish("suspend devices");
 256         if (suspend_test(TEST_DEVICES))
 257                 goto Recover_platform;
 258
 259         do {
 260                 error = suspend_enter(state, &wakeup);
 261         } while (!error && !wakeup
 262                 && suspend_ops->suspend_again && suspend_ops->suspend_again());
 263
 264  Resume_devices:
 265         suspend_test_start();
 266         dpm_resume_end(PMSG_RESUME);
 267         suspend_test_finish("resume devices");
 268         resume_console();
 269  Close:
 270         if (suspend_ops->end)
 271                 suspend_ops->end();
 272         trace_machine_suspend(PWR_EVENT_EXIT);
 273         return error;
 274
 275  Recover_platform:
 276         if (suspend_ops->recover)
 277                 suspend_ops->recover();
 278         goto Resume_devices;
 279 }
 280
 281 /**
 282  *      suspend_finish - Do final work before exiting suspend sequence.
 283  *
 284  *      Call platform code to clean up, restart processes, and free the
 285  *      console that we've allocated. This is not called for suspend-to-disk.
 286  */
 287 static void suspend_finish(void)
 288 {
 289         suspend_thaw_processes();
 290         usermodehelper_enable();
 291         pm_notifier_call_chain(PM_POST_SUSPEND);
 292         pm_restore_console();
 293 }
 294
 295 #ifdef CONFIG_PM_WATCHDOG_TIMEOUT
 296 void pm_wd_timeout(unsigned long data)
 297 {
 298         struct pm_wd_data *wd_data = (void *)data;
 299         struct task_struct *tsk = wd_data->tsk;
 300
 301         pr_emerg("%s: PM watchdog timeout: %d seconds\n",  __func__,
 302                         wd_data->timeout);
 303
 304         pr_emerg("stack:\n");
 305         show_stack(tsk, NULL);
 306
 307         BUG();
 308 }
 309
 310 void pm_wd_add_timer(struct timer_list *timer, struct pm_wd_data *data,
 311                         int timeout)
 312 {
 313         data->timeout = timeout;
 314         data->tsk = get_current();
 315         init_timer_on_stack(timer);
 316         timer->expires = jiffies + HZ * data->timeout;
 317         timer->function = pm_wd_timeout;
 318         timer->data = (unsigned long)data;
 319         add_timer(timer);
 320 }
 321
 322 void pm_wd_del_timer(struct timer_list *timer)
 323 {
 324         del_timer_sync(timer);
 325         destroy_timer_on_stack(timer);
 326 }
 327 #endif
 328
 329 /**
 330  *      enter_state - Do common work of entering low-power state.
 331  *      @state:         pm_state structure for state we're entering.
 332  *
 333  *      Make sure we're the only ones trying to enter a sleep state. Fail
 334  *      if someone has beat us to it, since we don't want anything weird to
 335  *      happen when we wake up.
 336  *      Then, do the setup for suspend, enter the state, and cleaup (after
 337  *      we've woken up).
 338  */
 339 int enter_state(suspend_state_t state)
 340 {
 341         int error;
 342         struct timer_list timer;
 343         struct pm_wd_data data;
 344
 345         if (!valid_state(state))
 346                 return -ENODEV;
 347
 348         if (!mutex_trylock(&pm_mutex))
 349                 return -EBUSY;
 350
 351         printk(KERN_INFO "PM: Syncing filesystems ... ");
 352         sys_sync();
 353         printk("done.\n");
 354
 355         pr_debug("PM: Preparing system for %s sleep\n", pm_states[state]);
 356         error = suspend_prepare();
 357         if (error)
 358                 goto Unlock;
 359
 360         if (suspend_test(TEST_FREEZER))
 361                 goto Finish;
 362
 363         pr_debug("PM: Entering %s sleep\n", pm_states[state]);
 364         pm_restrict_gfp_mask();
 365         error = suspend_devices_and_enter(state);
 366         pm_restore_gfp_mask();
 367
 368  Finish:
 369         pm_wd_add_timer(&timer, &data, 15);
 370
 371         pr_debug("PM: Finishing wakeup.\n");
 372         suspend_finish();
 373
 374         pm_wd_del_timer(&timer);
 375  Unlock:
 376         mutex_unlock(&pm_mutex);
 377         return error;
 378 }
 379
 380 /**
 381  *      pm_suspend - Externally visible function for suspending system.
 382  *      @state:         Enumerated value of state to enter.
 383  *
 384  *      Determine whether or not value is within range, get state
 385  *      structure, and enter (above).
 386  */
 387 int pm_suspend(suspend_state_t state)
 388 {
 389         if (state > PM_SUSPEND_ON && state < PM_SUSPEND_MAX)
 390                 return enter_state(state);
 391         return -EINVAL;
 392 }
 393 EXPORT_SYMBOL(pm_suspend);