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 <trace/events/power.h>
  29
  30 #include "power.h"
  31
  32 const char *const pm_states[PM_SUSPEND_MAX] = {
  33         [PM_SUSPEND_STANDBY]    = "standby",
  34         [PM_SUSPEND_MEM]        = "mem",
  35 };
  36
  37 static const struct platform_suspend_ops *suspend_ops;
  38
  39 /**
  40  * suspend_set_ops - Set the global suspend method table.
  41  * @ops: Suspend operations to use.
  42  */
  43 void suspend_set_ops(const struct platform_suspend_ops *ops)
  44 {
  45         lock_system_sleep();
  46         suspend_ops = ops;
  47         unlock_system_sleep();
  48 }
  49 EXPORT_SYMBOL_GPL(suspend_set_ops);
  50
  51 bool valid_state(suspend_state_t state)
  52 {
  53         /*
  54          * All states need lowlevel support and need to be valid to the lowlevel
  55          * implementation, no valid callback implies that none are valid.
  56          */
  57         return suspend_ops && suspend_ops->valid && suspend_ops->valid(state);
  58 }
  59
  60 /**
  61  * suspend_valid_only_mem - Generic memory-only valid callback.
  62  *
  63  * Platform drivers that implement mem suspend only and only need to check for
  64  * that in their .valid() callback can use this instead of rolling their own
  65  * .valid() callback.
  66  */
  67 int suspend_valid_only_mem(suspend_state_t state)
  68 {
  69         return state == PM_SUSPEND_MEM;
  70 }
  71 EXPORT_SYMBOL_GPL(suspend_valid_only_mem);
  72
  73 static int suspend_test(int level)
  74 {
  75 #ifdef CONFIG_PM_DEBUG
  76         if (pm_test_level == level) {
  77                 printk(KERN_INFO "suspend debug: Waiting for 5 seconds.\n");
  78                 mdelay(5000);
  79                 return 1;
  80         }
  81 #endif /* !CONFIG_PM_DEBUG */
  82         return 0;
  83 }
  84
  85 /**
  86  * suspend_prepare - Prepare for entering system sleep state.
  87  *
  88  * Common code run for every system sleep state that can be entered (except for
  89  * hibernation).  Run suspend notifiers, allocate the "suspend" console and
  90  * freeze 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                 return 0;
 112
 113         suspend_stats.failed_freeze++;
 114         dpm_save_failed_step(SUSPEND_FREEZE);
 115         usermodehelper_enable();
 116  Finish:
 117         pm_notifier_call_chain(PM_POST_SUSPEND);
 118         pm_restore_console();
 119         return error;
 120 }
 121
 122 /* default implementation */
 123 void __attribute__ ((weak)) arch_suspend_disable_irqs(void)
 124 {
 125         local_irq_disable();
 126 }
 127
 128 /* default implementation */
 129 void __attribute__ ((weak)) arch_suspend_enable_irqs(void)
 130 {
 131         local_irq_enable();
 132 }
 133
 134 /**
 135  * suspend_enter - Make the system enter the given sleep state.
 136  * @state: System sleep state to enter.
 137  * @wakeup: Returns information that the sleep state should not be re-entered.
 138  *
 139  * This function should be called after devices have been suspended.
 140  */
 141 static int suspend_enter(suspend_state_t state, bool *wakeup)
 142 {
 143         int error;
 144
 145         if (suspend_ops->prepare) {
 146                 error = suspend_ops->prepare();
 147                 if (error)
 148                         goto Platform_finish;
 149         }
 150
 151         error = dpm_suspend_end(PMSG_SUSPEND);
 152         if (error) {
 153                 printk(KERN_ERR "PM: Some devices failed to power down\n");
 154                 goto Platform_finish;
 155         }
 156
 157         if (suspend_ops->prepare_late) {
 158                 error = suspend_ops->prepare_late();
 159                 if (error)
 160                         goto Platform_wake;
 161         }
 162
 163         if (suspend_test(TEST_PLATFORM))
 164                 goto Platform_wake;
 165
 166         error = disable_nonboot_cpus();
 167         if (error || suspend_test(TEST_CPUS))
 168                 goto Enable_cpus;
 169
 170         arch_suspend_disable_irqs();
 171         BUG_ON(!irqs_disabled());
 172
 173         error = syscore_suspend();
 174         if (!error) {
 175                 *wakeup = pm_wakeup_pending();
 176                 if (!(suspend_test(TEST_CORE) || *wakeup)) {
 177                         error = suspend_ops->enter(state);
 178                         events_check_enabled = false;
 179                 }
 180                 syscore_resume();
 181         }
 182
 183         arch_suspend_enable_irqs();
 184         BUG_ON(irqs_disabled());
 185
 186  Enable_cpus:
 187         enable_nonboot_cpus();
 188
 189  Platform_wake:
 190         if (suspend_ops->wake)
 191                 suspend_ops->wake();
 192
 193         dpm_resume_start(PMSG_RESUME);
 194
 195  Platform_finish:
 196         if (suspend_ops->finish)
 197                 suspend_ops->finish();
 198
 199         return error;
 200 }
 201
 202 /**
 203  * suspend_devices_and_enter - Suspend devices and enter system sleep state.
 204  * @state: System sleep state to enter.
 205  */
 206 int suspend_devices_and_enter(suspend_state_t state)
 207 {
 208         int error;
 209         bool wakeup = false;
 210
 211         if (!suspend_ops)
 212                 return -ENOSYS;
 213
 214         trace_machine_suspend(state);
 215         if (suspend_ops->begin) {
 216                 error = suspend_ops->begin(state);
 217                 if (error)
 218                         goto Close;
 219         }
 220         suspend_console();
 221         suspend_test_start();
 222         error = dpm_suspend_start(PMSG_SUSPEND);
 223         if (error) {
 224                 printk(KERN_ERR "PM: Some devices failed to suspend\n");
 225                 goto Recover_platform;
 226         }
 227         suspend_test_finish("suspend devices");
 228         if (suspend_test(TEST_DEVICES))
 229                 goto Recover_platform;
 230
 231         do {
 232                 error = suspend_enter(state, &wakeup);
 233         } while (!error && !wakeup
 234                 && suspend_ops->suspend_again && suspend_ops->suspend_again());
 235
 236  Resume_devices:
 237         suspend_test_start();
 238         dpm_resume_end(PMSG_RESUME);
 239         suspend_test_finish("resume devices");
 240         resume_console();
 241  Close:
 242         if (suspend_ops->end)
 243                 suspend_ops->end();
 244         trace_machine_suspend(PWR_EVENT_EXIT);
 245         return error;
 246
 247  Recover_platform:
 248         if (suspend_ops->recover)
 249                 suspend_ops->recover();
 250         goto Resume_devices;
 251 }
 252
 253 /**
 254  * suspend_finish - Clean up before finishing the suspend sequence.
 255  *
 256  * Call platform code to clean up, restart processes, and free the console that
 257  * we've allocated. This routine is not called for hibernation.
 258  */
 259 static void suspend_finish(void)
 260 {
 261         suspend_thaw_processes();
 262         usermodehelper_enable();
 263         pm_notifier_call_chain(PM_POST_SUSPEND);
 264         pm_restore_console();
 265 }
 266
 267 /**
 268  * enter_state - Do common work needed to enter system sleep state.
 269  * @state: System sleep state to enter.
 270  *
 271  * Make sure that no one else is trying to put the system into a sleep state.
 272  * Fail if that's not the case.  Otherwise, prepare for system suspend, make the
 273  * system enter the given sleep state and clean up after wakeup.
 274  */
 275 static int enter_state(suspend_state_t state)
 276 {
 277         int error;
 278
 279         if (!valid_state(state))
 280                 return -ENODEV;
 281
 282         if (!mutex_trylock(&pm_mutex))
 283                 return -EBUSY;
 284
 285         printk(KERN_INFO "PM: Syncing filesystems ... ");
 286         sys_sync();
 287         printk("done.\n");
 288
 289         pr_debug("PM: Preparing system for %s sleep\n", pm_states[state]);
 290         error = suspend_prepare();
 291         if (error)
 292                 goto Unlock;
 293
 294         if (suspend_test(TEST_FREEZER))
 295                 goto Finish;
 296
 297         pr_debug("PM: Entering %s sleep\n", pm_states[state]);
 298         pm_restrict_gfp_mask();
 299         error = suspend_devices_and_enter(state);
 300         pm_restore_gfp_mask();
 301
 302  Finish:
 303         pr_debug("PM: Finishing wakeup.\n");
 304         suspend_finish();
 305  Unlock:
 306         mutex_unlock(&pm_mutex);
 307         return error;
 308 }
 309
 310 /**
 311  * pm_suspend - Externally visible function for suspending the system.
 312  * @state: System sleep state to enter.
 313  *
 314  * Check if the value of @state represents one of the supported states,
 315  * execute enter_state() and update system suspend statistics.
 316  */
 317 int pm_suspend(suspend_state_t state)
 318 {
 319         int error;
 320
 321         if (state <= PM_SUSPEND_ON || state >= PM_SUSPEND_MAX)
 322                 return -EINVAL;
 323
 324         error = enter_state(state);
 325         if (error) {
 326                 suspend_stats.fail++;
 327                 dpm_save_failed_errno(error);
 328         } else {
 329                 suspend_stats.success++;
 330         }
 331         return error;
 332 }
 333 EXPORT_SYMBOL(pm_suspend);