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/kmod.h>
  16 #include <linux/console.h>
  17 #include <linux/cpu.h>
  18 #include <linux/syscalls.h>
  19 #include <linux/gfp.h>
  20 #include <linux/io.h>
  21 #include <linux/kernel.h>
  22 #include <linux/list.h>
  23 #include <linux/mm.h>
  24 #include <linux/slab.h>
  25 #include <linux/export.h>
  26 #include <linux/suspend.h>
  27 #include <linux/syscore_ops.h>
  28 #include <linux/ftrace.h>
  29 #include <trace/events/power.h>
  30
  31 #include "power.h"
  32
  33 const char *const pm_states[PM_SUSPEND_MAX] = {
  34         [PM_SUSPEND_STANDBY]    = "standby",
  35         [PM_SUSPEND_MEM]        = "mem",
  36 };
  37
  38 static const struct platform_suspend_ops *suspend_ops;
  39
  40 /**
  41  *      suspend_set_ops - Set the global suspend method table.
  42  *      @ops:   Pointer to ops structure.
  43  */
  44 void suspend_set_ops(const struct platform_suspend_ops *ops)
  45 {
  46         mutex_lock(&pm_mutex);
  47         suspend_ops = ops;
  48         mutex_unlock(&pm_mutex);
  49 }
  50 EXPORT_SYMBOL_GPL(suspend_set_ops);
  51
  52 bool valid_state(suspend_state_t state)
  53 {
  54         /*
  55          * All states need lowlevel support and need to be valid to the lowlevel
  56          * implementation, no valid callback implies that none are valid.
  57          */
  58         return suspend_ops && suspend_ops->valid && suspend_ops->valid(state);
  59 }
  60
  61 /**
  62  * suspend_valid_only_mem - generic memory-only valid callback
  63  *
  64  * Platform drivers that implement mem suspend only and only need
  65  * to check for that in their .valid callback can use this instead
  66  * of rolling their own .valid callback.
  67  */
  68 int suspend_valid_only_mem(suspend_state_t state)
  69 {
  70         return state == PM_SUSPEND_MEM;
  71 }
  72 EXPORT_SYMBOL_GPL(suspend_valid_only_mem);
  73
  74 static int suspend_test(int level)
  75 {
  76 #ifdef CONFIG_PM_DEBUG
  77         if (pm_test_level == level) {
  78                 printk(KERN_INFO "suspend debug: Waiting for 5 seconds.\n");
  79                 mdelay(5000);
  80                 return 1;
  81         }
  82 #endif /* !CONFIG_PM_DEBUG */
  83         return 0;
  84 }
  85
  86 /**
  87  *      suspend_prepare - Do prep work before entering low-power state.
  88  *
  89  *      This is common code that is called for each state that we're entering.
  90  *      Run suspend notifiers, allocate a console and stop all processes.
  91  */
  92 static int suspend_prepare(void)
  93 {
  94         int error;
  95
  96         if (!suspend_ops || !suspend_ops->enter)
  97                 return -EPERM;
  98
  99         pm_prepare_console();
 100
 101         error = pm_notifier_call_chain(PM_SUSPEND_PREPARE);
 102         if (error)
 103                 goto Finish;
 104
 105         error = usermodehelper_disable();
 106         if (error)
 107                 goto Finish;
 108
 109         error = suspend_freeze_processes();
 110         if (error) {
 111                 suspend_stats.failed_freeze++;
 112                 dpm_save_failed_step(SUSPEND_FREEZE);
 113         } else
 114                 return 0;
 115
 116         suspend_thaw_processes();
 117         usermodehelper_enable();
 118  Finish:
 119         pm_notifier_call_chain(PM_POST_SUSPEND);
 120         pm_restore_console();
 121         return error;
 122 }
 123
 124 /* default implementation */
 125 void __attribute__ ((weak)) arch_suspend_disable_irqs(void)
 126 {
 127         local_irq_disable();
 128 }
 129
 130 /* default implementation */
 131 void __attribute__ ((weak)) arch_suspend_enable_irqs(void)
 132 {
 133         local_irq_enable();
 134 }
 135
 136 /**
 137  * suspend_enter - enter the desired system sleep state.
 138  * @state: State to enter
 139  * @wakeup: Returns information that suspend should not be entered again.
 140  *
 141  * This function should be called after devices have been suspended.
 142  */
 143 static int suspend_enter(suspend_state_t state, bool *wakeup)
 144 {
 145         int error;
 146
 147         if (suspend_ops->prepare) {
 148                 error = suspend_ops->prepare();
 149                 if (error)
 150                         goto Platform_finish;
 151         }
 152
 153         error = dpm_suspend_noirq(PMSG_SUSPEND);
 154         if (error) {
 155                 printk(KERN_ERR "PM: Some devices failed to power down\n");
 156                 goto Platform_finish;
 157         }
 158
 159         if (suspend_ops->prepare_late) {
 160                 error = suspend_ops->prepare_late();
 161                 if (error)
 162                         goto Platform_wake;
 163         }
 164
 165         if (suspend_test(TEST_PLATFORM))
 166                 goto Platform_wake;
 167
 168         error = disable_nonboot_cpus();
 169         if (error || suspend_test(TEST_CPUS))
 170                 goto Enable_cpus;
 171
 172         arch_suspend_disable_irqs();
 173         BUG_ON(!irqs_disabled());
 174
 175         error = syscore_suspend();
 176         if (!error) {
 177                 *wakeup = pm_wakeup_pending();
 178                 if (!(suspend_test(TEST_CORE) || *wakeup)) {
 179                         error = suspend_ops->enter(state);
 180                         events_check_enabled = false;
 181                 }
 182                 syscore_resume();
 183         }
 184
 185         arch_suspend_enable_irqs();
 186         BUG_ON(irqs_disabled());
 187
 188  Enable_cpus:
 189         enable_nonboot_cpus();
 190
 191  Platform_wake:
 192         if (suspend_ops->wake)
 193                 suspend_ops->wake();
 194
 195         dpm_resume_noirq(PMSG_RESUME);
 196
 197  Platform_finish:
 198         if (suspend_ops->finish)
 199                 suspend_ops->finish();
 200
 201         return error;
 202 }
 203
 204 /**
 205  *      suspend_devices_and_enter - suspend devices and enter the desired system
 206  *                                  sleep state.
 207  *      @state:           state to enter
 208  */
 209 int suspend_devices_and_enter(suspend_state_t state)
 210 {
 211         int error;
 212         bool wakeup = false;
 213
 214         if (!suspend_ops)
 215                 return -ENOSYS;
 216
 217         trace_machine_suspend(state);
 218         if (suspend_ops->begin) {
 219                 error = suspend_ops->begin(state);
 220                 if (error)
 221                         goto Close;
 222         }
 223         suspend_console();
 224         ftrace_stop();
 225         suspend_test_start();
 226         error = dpm_suspend_start(PMSG_SUSPEND);
 227         if (error) {
 228                 printk(KERN_ERR "PM: Some devices failed to suspend\n");
 229                 goto Recover_platform;
 230         }
 231         suspend_test_finish("suspend devices");
 232         if (suspend_test(TEST_DEVICES))
 233                 goto Recover_platform;
 234
 235         do {
 236                 error = suspend_enter(state, &wakeup);
 237         } while (!error && !wakeup
 238                 && suspend_ops->suspend_again && suspend_ops->suspend_again());
 239
 240  Resume_devices:
 241         suspend_test_start();
 242         dpm_resume_end(PMSG_RESUME);
 243         suspend_test_finish("resume devices");
 244         ftrace_start();
 245         resume_console();
 246  Close:
 247         if (suspend_ops->end)
 248                 suspend_ops->end();
 249         trace_machine_suspend(PWR_EVENT_EXIT);
 250         return error;
 251
 252  Recover_platform:
 253         if (suspend_ops->recover)
 254                 suspend_ops->recover();
 255         goto Resume_devices;
 256 }
 257
 258 /**
 259  *      suspend_finish - Do final work before exiting suspend sequence.
 260  *
 261  *      Call platform code to clean up, restart processes, and free the
 262  *      console that we've allocated. This is not called for suspend-to-disk.
 263  */
 264 static void suspend_finish(void)
 265 {
 266         suspend_thaw_processes();
 267         usermodehelper_enable();
 268         pm_notifier_call_chain(PM_POST_SUSPEND);
 269         pm_restore_console();
 270 }
 271
 272 /**
 273  *      enter_state - Do common work of entering low-power state.
 274  *      @state:         pm_state structure for state we're entering.
 275  *
 276  *      Make sure we're the only ones trying to enter a sleep state. Fail
 277  *      if someone has beat us to it, since we don't want anything weird to
 278  *      happen when we wake up.
 279  *      Then, do the setup for suspend, enter the state, and cleaup (after
 280  *      we've woken up).
 281  */
 282 int enter_state(suspend_state_t state)
 283 {
 284         int error;
 285
 286         if (!valid_state(state))
 287                 return -ENODEV;
 288
 289         if (!mutex_trylock(&pm_mutex))
 290                 return -EBUSY;
 291
 292         printk(KERN_INFO "PM: Syncing filesystems ... ");
 293         sys_sync();
 294         printk("done.\n");
 295
 296         pr_debug("PM: Preparing system for %s sleep\n", pm_states[state]);
 297         error = suspend_prepare();
 298         if (error)
 299                 goto Unlock;
 300
 301         if (suspend_test(TEST_FREEZER))
 302                 goto Finish;
 303
 304         pr_debug("PM: Entering %s sleep\n", pm_states[state]);
 305         pm_restrict_gfp_mask();
 306         error = suspend_devices_and_enter(state);
 307         pm_restore_gfp_mask();
 308
 309  Finish:
 310         pr_debug("PM: Finishing wakeup.\n");
 311         suspend_finish();
 312  Unlock:
 313         mutex_unlock(&pm_mutex);
 314         return error;
 315 }
 316
 317 /**
 318  *      pm_suspend - Externally visible function for suspending system.
 319  *      @state:         Enumerated value of state to enter.
 320  *
 321  *      Determine whether or not value is within range, get state
 322  *      structure, and enter (above).
 323  */
 324 int pm_suspend(suspend_state_t state)
 325 {
 326         int ret;
 327         if (state > PM_SUSPEND_ON && state < PM_SUSPEND_MAX) {
 328                 ret = enter_state(state);
 329                 if (ret) {
 330                         suspend_stats.fail++;
 331                         dpm_save_failed_errno(ret);
 332                 } else
 333                         suspend_stats.success++;
 334                 return ret;
 335         }
 336         return -EINVAL;
 337 }
 338 EXPORT_SYMBOL(pm_suspend);