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