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