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