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_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 = suspend_freeze_processes();
 106         if (!error)
 107                 return 0;
 108
 109         suspend_stats.failed_freeze++;
 110         dpm_save_failed_step(SUSPEND_FREEZE);
 111  Finish:
 112         pm_notifier_call_chain(PM_POST_SUSPEND);
 113         pm_restore_console();
 114         return error;
 115 }
 116
 117 /* default implementation */
 118 void __attribute__ ((weak)) arch_suspend_disable_irqs(void)
 119 {
 120         local_irq_disable();
 121 }
 122
 123 /* default implementation */
 124 void __attribute__ ((weak)) arch_suspend_enable_irqs(void)
 125 {
 126         local_irq_enable();
 127 }
 128
 129 /**
 130  * suspend_enter - Make the system enter the given sleep state.
 131  * @state: System sleep state to enter.
 132  * @wakeup: Returns information that the sleep state should not be re-entered.
 133  *
 134  * This function should be called after devices have been suspended.
 135  */
 136 static int suspend_enter(suspend_state_t state, bool *wakeup)
 137 {
 138         int error;
 139
 140         if (suspend_ops->prepare) {
 141                 error = suspend_ops->prepare();
 142                 if (error)
 143                         goto Platform_finish;
 144         }
 145
 146         error = dpm_suspend_end(PMSG_SUSPEND);
 147         if (error) {
 148                 printk(KERN_ERR "PM: Some devices failed to power down\n");
 149                 goto Platform_finish;
 150         }
 151
 152         if (suspend_ops->prepare_late) {
 153                 error = suspend_ops->prepare_late();
 154                 if (error)
 155                         goto Platform_wake;
 156         }
 157
 158         if (suspend_test(TEST_PLATFORM))
 159                 goto Platform_wake;
 160
 161         error = disable_nonboot_cpus();
 162         if (error || suspend_test(TEST_CPUS))
 163                 goto Enable_cpus;
 164
 165         arch_suspend_disable_irqs();
 166         BUG_ON(!irqs_disabled());
 167
 168         error = syscore_suspend();
 169         if (!error) {
 170                 *wakeup = pm_wakeup_pending();
 171                 if (!(suspend_test(TEST_CORE) || *wakeup)) {
 172                         error = suspend_ops->enter(state);
 173                         events_check_enabled = false;
 174                 }
 175                 syscore_resume();
 176         }
 177
 178         arch_suspend_enable_irqs();
 179         BUG_ON(irqs_disabled());
 180
 181  Enable_cpus:
 182         enable_nonboot_cpus();
 183
 184  Platform_wake:
 185         if (suspend_ops->wake)
 186                 suspend_ops->wake();
 187
 188         dpm_resume_start(PMSG_RESUME);
 189
 190  Platform_finish:
 191         if (suspend_ops->finish)
 192                 suspend_ops->finish();
 193
 194         return error;
 195 }
 196
 197 /**
 198  * suspend_devices_and_enter - Suspend devices and enter system sleep state.
 199  * @state: System sleep state to enter.
 200  */
 201 int suspend_devices_and_enter(suspend_state_t state)
 202 {
 203         int error;
 204         bool wakeup = false;
 205
 206         if (!suspend_ops)
 207                 return -ENOSYS;
 208
 209         trace_machine_suspend(state);
 210         if (suspend_ops->begin) {
 211                 error = suspend_ops->begin(state);
 212                 if (error)
 213                         goto Close;
 214         }
 215         suspend_console();
 216         ftrace_stop();
 217         suspend_test_start();
 218         error = dpm_suspend_start(PMSG_SUSPEND);
 219         if (error) {
 220                 printk(KERN_ERR "PM: Some devices failed to suspend\n");
 221                 goto Recover_platform;
 222         }
 223         suspend_test_finish("suspend devices");
 224         if (suspend_test(TEST_DEVICES))
 225                 goto Recover_platform;
 226
 227         do {
 228                 error = suspend_enter(state, &wakeup);
 229         } while (!error && !wakeup
 230                 && suspend_ops->suspend_again && suspend_ops->suspend_again());
 231
 232  Resume_devices:
 233         suspend_test_start();
 234         dpm_resume_end(PMSG_RESUME);
 235         suspend_test_finish("resume devices");
 236         ftrace_start();
 237         resume_console();
 238  Close:
 239         if (suspend_ops->end)
 240                 suspend_ops->end();
 241         trace_machine_suspend(PWR_EVENT_EXIT);
 242         return error;
 243
 244  Recover_platform:
 245         if (suspend_ops->recover)
 246                 suspend_ops->recover();
 247         goto Resume_devices;
 248 }
 249
 250 /**
 251  * suspend_finish - Clean up before finishing the suspend sequence.
 252  *
 253  * Call platform code to clean up, restart processes, and free the console that
 254  * we've allocated. This routine is not called for hibernation.
 255  */
 256 static void suspend_finish(void)
 257 {
 258         suspend_thaw_processes();
 259         pm_notifier_call_chain(PM_POST_SUSPEND);
 260         pm_restore_console();
 261 }
 262
 263 /**
 264  * enter_state - Do common work needed to enter system sleep state.
 265  * @state: System sleep state to enter.
 266  *
 267  * Make sure that no one else is trying to put the system into a sleep state.
 268  * Fail if that's not the case.  Otherwise, prepare for system suspend, make the
 269  * system enter the given sleep state and clean up after wakeup.
 270  */
 271 static int enter_state(suspend_state_t state)
 272 {
 273         int error;
 274
 275         if (!valid_state(state))
 276                 return -ENODEV;
 277
 278         if (!mutex_trylock(&pm_mutex))
 279                 return -EBUSY;
 280
 281         printk(KERN_INFO "PM: Syncing filesystems ... ");
 282         sys_sync();
 283         printk("done.\n");
 284
 285         pr_debug("PM: Preparing system for %s sleep\n", pm_states[state]);
 286         error = suspend_prepare();
 287         if (error)
 288                 goto Unlock;
 289
 290         if (suspend_test(TEST_FREEZER))
 291                 goto Finish;
 292
 293         pr_debug("PM: Entering %s sleep\n", pm_states[state]);
 294         pm_restrict_gfp_mask();
 295         error = suspend_devices_and_enter(state);
 296         pm_restore_gfp_mask();
 297
 298  Finish:
 299         pr_debug("PM: Finishing wakeup.\n");
 300         suspend_finish();
 301  Unlock:
 302         mutex_unlock(&pm_mutex);
 303         return error;
 304 }
 305
 306 /**
 307  * pm_suspend - Externally visible function for suspending the system.
 308  * @state: System sleep state to enter.
 309  *
 310  * Check if the value of @state represents one of the supported states,
 311  * execute enter_state() and update system suspend statistics.
 312  */
 313 int pm_suspend(suspend_state_t state)
 314 {
 315         int error;
 316
 317         if (state <= PM_SUSPEND_ON || state >= PM_SUSPEND_MAX)
 318                 return -EINVAL;
 319
 320         error = enter_state(state);
 321         if (error) {
 322                 suspend_stats.fail++;
 323                 dpm_save_failed_errno(error);
 324         } else {
 325                 suspend_stats.success++;
 326         }
 327         return error;
 328 }
 329 EXPORT_SYMBOL(pm_suspend);