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 struct pm_sleep_state pm_states[PM_SUSPEND_MAX] = {
  33         [PM_SUSPEND_FREEZE] = { .label = "freeze", .state = PM_SUSPEND_FREEZE },
  34         [PM_SUSPEND_STANDBY] = { .label = "standby", },
  35         [PM_SUSPEND_MEM] = { .label = "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 static bool valid_state(suspend_state_t state)
  66 {
  67         /*
  68          * PM_SUSPEND_STANDBY and PM_SUSPEND_MEM states need low level
  69          * support and need to be valid to the low level
  70          * implementation, no valid callback implies that none are valid.
  71          */
  72         return suspend_ops && suspend_ops->valid && suspend_ops->valid(state);
  73 }
  74
  75 /**
  76  * suspend_set_ops - Set the global suspend method table.
  77  * @ops: Suspend operations to use.
  78  */
  79 void suspend_set_ops(const struct platform_suspend_ops *ops)
  80 {
  81         suspend_state_t i;
  82
  83         lock_system_sleep();
  84
  85         suspend_ops = ops;
  86         for (i = PM_SUSPEND_STANDBY; i <= PM_SUSPEND_MEM; i++)
  87                 pm_states[i].state = valid_state(i) ? i : 0;
  88
  89         unlock_system_sleep();
  90 }
  91 EXPORT_SYMBOL_GPL(suspend_set_ops);
  92
  93 /**
  94  * suspend_valid_only_mem - Generic memory-only valid callback.
  95  *
  96  * Platform drivers that implement mem suspend only and only need to check for
  97  * that in their .valid() callback can use this instead of rolling their own
  98  * .valid() callback.
  99  */
 100 int suspend_valid_only_mem(suspend_state_t state)
 101 {
 102         return state == PM_SUSPEND_MEM;
 103 }
 104 EXPORT_SYMBOL_GPL(suspend_valid_only_mem);
 105
 106 static int suspend_test(int level)
 107 {
 108 #ifdef CONFIG_PM_DEBUG
 109         if (pm_test_level == level) {
 110                 printk(KERN_INFO "suspend debug: Waiting for 5 seconds.\n");
 111                 mdelay(5000);
 112                 return 1;
 113         }
 114 #endif /* !CONFIG_PM_DEBUG */
 115         return 0;
 116 }
 117
 118 /**
 119  * suspend_prepare - Prepare for entering system sleep state.
 120  *
 121  * Common code run for every system sleep state that can be entered (except for
 122  * hibernation).  Run suspend notifiers, allocate the "suspend" console and
 123  * freeze processes.
 124  */
 125 static int suspend_prepare(suspend_state_t state)
 126 {
 127         int error;
 128
 129         if (need_suspend_ops(state) && (!suspend_ops || !suspend_ops->enter))
 130                 return -EPERM;
 131
 132         pm_prepare_console();
 133
 134         error = pm_notifier_call_chain(PM_SUSPEND_PREPARE);
 135         if (error)
 136                 goto Finish;
 137
 138         error = suspend_freeze_processes();
 139         if (!error)
 140                 return 0;
 141
 142         suspend_stats.failed_freeze++;
 143         dpm_save_failed_step(SUSPEND_FREEZE);
 144  Finish:
 145         pm_notifier_call_chain(PM_POST_SUSPEND);
 146         pm_restore_console();
 147         return error;
 148 }
 149
 150 /* default implementation */
 151 void __attribute__ ((weak)) arch_suspend_disable_irqs(void)
 152 {
 153         local_irq_disable();
 154 }
 155
 156 /* default implementation */
 157 void __attribute__ ((weak)) arch_suspend_enable_irqs(void)
 158 {
 159         local_irq_enable();
 160 }
 161
 162 /**
 163  * suspend_enter - Make the system enter the given sleep state.
 164  * @state: System sleep state to enter.
 165  * @wakeup: Returns information that the sleep state should not be re-entered.
 166  *
 167  * This function should be called after devices have been suspended.
 168  */
 169 static int suspend_enter(suspend_state_t state, bool *wakeup)
 170 {
 171         int error;
 172
 173         if (need_suspend_ops(state) && suspend_ops->prepare) {
 174                 error = suspend_ops->prepare();
 175                 if (error)
 176                         goto Platform_finish;
 177         }
 178
 179         error = dpm_suspend_end(PMSG_SUSPEND);
 180         if (error) {
 181                 printk(KERN_ERR "PM: Some devices failed to power down\n");
 182                 goto Platform_finish;
 183         }
 184
 185         if (need_suspend_ops(state) && suspend_ops->prepare_late) {
 186                 error = suspend_ops->prepare_late();
 187                 if (error)
 188                         goto Platform_wake;
 189         }
 190
 191         if (suspend_test(TEST_PLATFORM))
 192                 goto Platform_wake;
 193
 194         /*
 195          * PM_SUSPEND_FREEZE equals
 196          * frozen processes + suspended devices + idle processors.
 197          * Thus we should invoke freeze_enter() soon after
 198          * all the devices are suspended.
 199          */
 200         if (state == PM_SUSPEND_FREEZE) {
 201                 freeze_enter();
 202                 goto Platform_wake;
 203         }
 204
 205         ftrace_stop();
 206         error = disable_nonboot_cpus();
 207         if (error || suspend_test(TEST_CPUS))
 208                 goto Enable_cpus;
 209
 210         arch_suspend_disable_irqs();
 211         BUG_ON(!irqs_disabled());
 212
 213         error = syscore_suspend();
 214         if (!error) {
 215                 *wakeup = pm_wakeup_pending();
 216                 if (!(suspend_test(TEST_CORE) || *wakeup)) {
 217                         error = suspend_ops->enter(state);
 218                         events_check_enabled = false;
 219                 }
 220                 syscore_resume();
 221         }
 222
 223         arch_suspend_enable_irqs();
 224         BUG_ON(irqs_disabled());
 225
 226  Enable_cpus:
 227         enable_nonboot_cpus();
 228         ftrace_start();
 229
 230  Platform_wake:
 231         if (need_suspend_ops(state) && suspend_ops->wake)
 232                 suspend_ops->wake();
 233
 234         dpm_resume_start(PMSG_RESUME);
 235
 236  Platform_finish:
 237         if (need_suspend_ops(state) && suspend_ops->finish)
 238                 suspend_ops->finish();
 239
 240         return error;
 241 }
 242
 243 /**
 244  * suspend_devices_and_enter - Suspend devices and enter system sleep state.
 245  * @state: System sleep state to enter.
 246  */
 247 int suspend_devices_and_enter(suspend_state_t state)
 248 {
 249         int error;
 250         bool wakeup = false;
 251
 252         if (need_suspend_ops(state) && !suspend_ops)
 253                 return -ENOSYS;
 254
 255         trace_machine_suspend(state);
 256         if (need_suspend_ops(state) && suspend_ops->begin) {
 257                 error = suspend_ops->begin(state);
 258                 if (error)
 259                         goto Close;
 260         }
 261         suspend_console();
 262         suspend_test_start();
 263         error = dpm_suspend_start(PMSG_SUSPEND);
 264         if (error) {
 265                 pr_err("PM: Some devices failed to suspend, or early wake event detected\n");
 266                 goto Recover_platform;
 267         }
 268         suspend_test_finish("suspend devices");
 269         if (suspend_test(TEST_DEVICES))
 270                 goto Recover_platform;
 271
 272         do {
 273                 error = suspend_enter(state, &wakeup);
 274         } while (!error && !wakeup && need_suspend_ops(state)
 275                 && suspend_ops->suspend_again && suspend_ops->suspend_again());
 276
 277  Resume_devices:
 278         suspend_test_start();
 279         dpm_resume_end(PMSG_RESUME);
 280         suspend_test_finish("resume devices");
 281         resume_console();
 282  Close:
 283         if (need_suspend_ops(state) && suspend_ops->end)
 284                 suspend_ops->end();
 285         trace_machine_suspend(PWR_EVENT_EXIT);
 286         return error;
 287
 288  Recover_platform:
 289         if (need_suspend_ops(state) && suspend_ops->recover)
 290                 suspend_ops->recover();
 291         goto Resume_devices;
 292 }
 293
 294 /**
 295  * suspend_finish - Clean up before finishing the suspend sequence.
 296  *
 297  * Call platform code to clean up, restart processes, and free the console that
 298  * we've allocated. This routine is not called for hibernation.
 299  */
 300 static void suspend_finish(void)
 301 {
 302         suspend_thaw_processes();
 303         pm_notifier_call_chain(PM_POST_SUSPEND);
 304         pm_restore_console();
 305 }
 306
 307 /**
 308  * enter_state - Do common work needed to enter system sleep state.
 309  * @state: System sleep state to enter.
 310  *
 311  * Make sure that no one else is trying to put the system into a sleep state.
 312  * Fail if that's not the case.  Otherwise, prepare for system suspend, make the
 313  * system enter the given sleep state and clean up after wakeup.
 314  */
 315 static int enter_state(suspend_state_t state)
 316 {
 317         int error;
 318
 319         if (state == PM_SUSPEND_FREEZE) {
 320 #ifdef CONFIG_PM_DEBUG
 321                 if (pm_test_level != TEST_NONE && pm_test_level <= TEST_CPUS) {
 322                         pr_warning("PM: Unsupported test mode for freeze state,"
 323                                    "please choose none/freezer/devices/platform.\n");
 324                         return -EAGAIN;
 325                 }
 326 #endif
 327         } else if (!valid_state(state)) {
 328                 return -EINVAL;
 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].label);
 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].label);
 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);