kernel/power/main.c

   1 /*
   2  * kernel/power/main.c - PM subsystem core functionality.
   3  *
   4  * Copyright (c) 2003 Patrick Mochel
   5  * Copyright (c) 2003 Open Source Development Lab
   6  *
   7  * This file is released under the GPLv2
   8  *
   9  */
  10
  11 #include <linux/module.h>
  12 #include <linux/suspend.h>
  13 #include <linux/kobject.h>
  14 #include <linux/string.h>
  15 #include <linux/delay.h>
  16 #include <linux/errno.h>
  17 #include <linux/init.h>
  18 #include <linux/console.h>
  19 #include <linux/cpu.h>
  20 #include <linux/resume-trace.h>
  21 #include <linux/freezer.h>
  22 #include <linux/vmstat.h>
  23 #include <linux/syscalls.h>
  24
  25 #include "power.h"
  26
  27 DEFINE_MUTEX(pm_mutex);
  28
  29 unsigned int pm_flags;
  30 EXPORT_SYMBOL(pm_flags);
  31
  32 #ifdef CONFIG_PM_SLEEP
  33
  34 /* Routines for PM-transition notifications */
  35
  36 static BLOCKING_NOTIFIER_HEAD(pm_chain_head);
  37
  38 int register_pm_notifier(struct notifier_block *nb)
  39 {
  40         return blocking_notifier_chain_register(&pm_chain_head, nb);
  41 }
  42 EXPORT_SYMBOL_GPL(register_pm_notifier);
  43
  44 int unregister_pm_notifier(struct notifier_block *nb)
  45 {
  46         return blocking_notifier_chain_unregister(&pm_chain_head, nb);
  47 }
  48 EXPORT_SYMBOL_GPL(unregister_pm_notifier);
  49
  50 int pm_notifier_call_chain(unsigned long val)
  51 {
  52         return (blocking_notifier_call_chain(&pm_chain_head, val, NULL)
  53                         == NOTIFY_BAD) ? -EINVAL : 0;
  54 }
  55
  56 #endif /* CONFIG_PM_SLEEP */
  57
  58 #ifdef CONFIG_PM_DEBUG
  59 int pm_test_level = TEST_NONE;
  60
  61 static int suspend_test(int level)
  62 {
  63         if (pm_test_level == level) {
  64                 printk(KERN_INFO "suspend debug: Waiting for 5 seconds.\n");
  65                 mdelay(5000);
  66                 return 1;
  67         }
  68         return 0;
  69 }
  70
  71 static const char * const pm_tests[__TEST_AFTER_LAST] = {
  72         [TEST_NONE] = "none",
  73         [TEST_CORE] = "core",
  74         [TEST_CPUS] = "processors",
  75         [TEST_PLATFORM] = "platform",
  76         [TEST_DEVICES] = "devices",
  77         [TEST_FREEZER] = "freezer",
  78 };
  79
  80 static ssize_t pm_test_show(struct kobject *kobj, struct kobj_attribute *attr,
  81                                 char *buf)
  82 {
  83         char *s = buf;
  84         int level;
  85
  86         for (level = TEST_FIRST; level <= TEST_MAX; level++)
  87                 if (pm_tests[level]) {
  88                         if (level == pm_test_level)
  89                                 s += sprintf(s, "[%s] ", pm_tests[level]);
  90                         else
  91                                 s += sprintf(s, "%s ", pm_tests[level]);
  92                 }
  93
  94         if (s != buf)
  95                 /* convert the last space to a newline */
  96                 *(s-1) = '\n';
  97
  98         return (s - buf);
  99 }
 100
 101 static ssize_t pm_test_store(struct kobject *kobj, struct kobj_attribute *attr,
 102                                 const char *buf, size_t n)
 103 {
 104         const char * const *s;
 105         int level;
 106         char *p;
 107         int len;
 108         int error = -EINVAL;
 109
 110         p = memchr(buf, '\n', n);
 111         len = p ? p - buf : n;
 112
 113         mutex_lock(&pm_mutex);
 114
 115         level = TEST_FIRST;
 116         for (s = &pm_tests[level]; level <= TEST_MAX; s++, level++)
 117                 if (*s && len == strlen(*s) && !strncmp(buf, *s, len)) {
 118                         pm_test_level = level;
 119                         error = 0;
 120                         break;
 121                 }
 122
 123         mutex_unlock(&pm_mutex);
 124
 125         return error ? error : n;
 126 }
 127
 128 power_attr(pm_test);
 129 #else /* !CONFIG_PM_DEBUG */
 130 static inline int suspend_test(int level) { return 0; }
 131 #endif /* !CONFIG_PM_DEBUG */
 132
 133
 134 #ifdef CONFIG_SUSPEND
 135
 136 /* This is just an arbitrary number */
 137 #define FREE_PAGE_NUMBER (100)
 138
 139 static struct platform_suspend_ops *suspend_ops;
 140
 141 /**
 142  *      suspend_set_ops - Set the global suspend method table.
 143  *      @ops:   Pointer to ops structure.
 144  */
 145
 146 void suspend_set_ops(struct platform_suspend_ops *ops)
 147 {
 148         mutex_lock(&pm_mutex);
 149         suspend_ops = ops;
 150         mutex_unlock(&pm_mutex);
 151 }
 152
 153 /**
 154  * suspend_valid_only_mem - generic memory-only valid callback
 155  *
 156  * Platform drivers that implement mem suspend only and only need
 157  * to check for that in their .valid callback can use this instead
 158  * of rolling their own .valid callback.
 159  */
 160 int suspend_valid_only_mem(suspend_state_t state)
 161 {
 162         return state == PM_SUSPEND_MEM;
 163 }
 164
 165 /**
 166  *      suspend_prepare - Do prep work before entering low-power state.
 167  *
 168  *      This is common code that is called for each state that we're entering.
 169  *      Run suspend notifiers, allocate a console and stop all processes.
 170  */
 171 static int suspend_prepare(void)
 172 {
 173         int error;
 174         unsigned int free_pages;
 175
 176         if (!suspend_ops || !suspend_ops->enter)
 177                 return -EPERM;
 178
 179         error = pm_notifier_call_chain(PM_SUSPEND_PREPARE);
 180         if (error)
 181                 goto Finish;
 182
 183         pm_prepare_console();
 184
 185         if (freeze_processes()) {
 186                 error = -EAGAIN;
 187                 goto Thaw;
 188         }
 189
 190         free_pages = global_page_state(NR_FREE_PAGES);
 191         if (free_pages < FREE_PAGE_NUMBER) {
 192                 pr_debug("PM: free some memory\n");
 193                 shrink_all_memory(FREE_PAGE_NUMBER - free_pages);
 194                 if (nr_free_pages() < FREE_PAGE_NUMBER) {
 195                         error = -ENOMEM;
 196                         printk(KERN_ERR "PM: No enough memory\n");
 197                 }
 198         }
 199         if (!error)
 200                 return 0;
 201
 202  Thaw:
 203         thaw_processes();
 204         pm_restore_console();
 205  Finish:
 206         pm_notifier_call_chain(PM_POST_SUSPEND);
 207         return error;
 208 }
 209
 210 /* default implementation */
 211 void __attribute__ ((weak)) arch_suspend_disable_irqs(void)
 212 {
 213         local_irq_disable();
 214 }
 215
 216 /* default implementation */
 217 void __attribute__ ((weak)) arch_suspend_enable_irqs(void)
 218 {
 219         local_irq_enable();
 220 }
 221
 222 /**
 223  *      suspend_enter - enter the desired system sleep state.
 224  *      @state:         state to enter
 225  *
 226  *      This function should be called after devices have been suspended.
 227  */
 228 static int suspend_enter(suspend_state_t state)
 229 {
 230         int error = 0;
 231
 232         arch_suspend_disable_irqs();
 233         BUG_ON(!irqs_disabled());
 234
 235         if ((error = device_power_down(PMSG_SUSPEND))) {
 236                 printk(KERN_ERR "Some devices failed to power down\n");
 237                 goto Done;
 238         }
 239
 240         if (!suspend_test(TEST_CORE))
 241                 error = suspend_ops->enter(state);
 242
 243         device_power_up();
 244  Done:
 245         arch_suspend_enable_irqs();
 246         BUG_ON(irqs_disabled());
 247         return error;
 248 }
 249
 250 /**
 251  *      suspend_devices_and_enter - suspend devices and enter the desired system sleep
 252  *                        state.
 253  *      @state:           state to enter
 254  */
 255 int suspend_devices_and_enter(suspend_state_t state)
 256 {
 257         int error;
 258
 259         if (!suspend_ops)
 260                 return -ENOSYS;
 261
 262         if (suspend_ops->set_target) {
 263                 error = suspend_ops->set_target(state);
 264                 if (error)
 265                         return error;
 266         }
 267         suspend_console();
 268         error = device_suspend(PMSG_SUSPEND);
 269         if (error) {
 270                 printk(KERN_ERR "Some devices failed to suspend\n");
 271                 goto Resume_console;
 272         }
 273
 274         if (suspend_test(TEST_DEVICES))
 275                 goto Resume_devices;
 276
 277         if (suspend_ops->prepare) {
 278                 error = suspend_ops->prepare();
 279                 if (error)
 280                         goto Resume_devices;
 281         }
 282
 283         if (suspend_test(TEST_PLATFORM))
 284                 goto Finish;
 285
 286         error = disable_nonboot_cpus();
 287         if (!error && !suspend_test(TEST_CPUS))
 288                 suspend_enter(state);
 289
 290         enable_nonboot_cpus();
 291  Finish:
 292         if (suspend_ops->finish)
 293                 suspend_ops->finish();
 294  Resume_devices:
 295         device_resume();
 296  Resume_console:
 297         resume_console();
 298         return error;
 299 }
 300
 301 /**
 302  *      suspend_finish - Do final work before exiting suspend sequence.
 303  *
 304  *      Call platform code to clean up, restart processes, and free the
 305  *      console that we've allocated. This is not called for suspend-to-disk.
 306  */
 307 static void suspend_finish(void)
 308 {
 309         thaw_processes();
 310         pm_restore_console();
 311         pm_notifier_call_chain(PM_POST_SUSPEND);
 312 }
 313
 314
 315
 316
 317 static const char * const pm_states[PM_SUSPEND_MAX] = {
 318         [PM_SUSPEND_STANDBY]    = "standby",
 319         [PM_SUSPEND_MEM]        = "mem",
 320 };
 321
 322 static inline int valid_state(suspend_state_t state)
 323 {
 324         /* All states need lowlevel support and need to be valid
 325          * to the lowlevel implementation, no valid callback
 326          * implies that none are valid. */
 327         if (!suspend_ops || !suspend_ops->valid || !suspend_ops->valid(state))
 328                 return 0;
 329         return 1;
 330 }
 331
 332
 333 /**
 334  *      enter_state - Do common work of entering low-power state.
 335  *      @state:         pm_state structure for state we're entering.
 336  *
 337  *      Make sure we're the only ones trying to enter a sleep state. Fail
 338  *      if someone has beat us to it, since we don't want anything weird to
 339  *      happen when we wake up.
 340  *      Then, do the setup for suspend, enter the state, and cleaup (after
 341  *      we've woken up).
 342  */
 343 static int enter_state(suspend_state_t state)
 344 {
 345         int error;
 346
 347         if (!valid_state(state))
 348                 return -ENODEV;
 349
 350         if (!mutex_trylock(&pm_mutex))
 351                 return -EBUSY;
 352
 353         printk("Syncing filesystems ... ");
 354         sys_sync();
 355         printk("done.\n");
 356
 357         pr_debug("PM: Preparing system for %s sleep\n", pm_states[state]);
 358         error = suspend_prepare();
 359         if (error)
 360                 goto Unlock;
 361
 362         if (suspend_test(TEST_FREEZER))
 363                 goto Finish;
 364
 365         pr_debug("PM: Entering %s sleep\n", pm_states[state]);
 366         error = suspend_devices_and_enter(state);
 367
 368  Finish:
 369         pr_debug("PM: Finishing wakeup.\n");
 370         suspend_finish();
 371  Unlock:
 372         mutex_unlock(&pm_mutex);
 373         return error;
 374 }
 375
 376
 377 /**
 378  *      pm_suspend - Externally visible function for suspending system.
 379  *      @state:         Enumerated value of state to enter.
 380  *
 381  *      Determine whether or not value is within range, get state
 382  *      structure, and enter (above).
 383  */
 384
 385 int pm_suspend(suspend_state_t state)
 386 {
 387         if (state > PM_SUSPEND_ON && state <= PM_SUSPEND_MAX)
 388                 return enter_state(state);
 389         return -EINVAL;
 390 }
 391
 392 EXPORT_SYMBOL(pm_suspend);
 393
 394 #endif /* CONFIG_SUSPEND */
 395
 396 struct kobject *power_kobj;
 397
 398 /**
 399  *      state - control system power state.
 400  *
 401  *      show() returns what states are supported, which is hard-coded to
 402  *      'standby' (Power-On Suspend), 'mem' (Suspend-to-RAM), and
 403  *      'disk' (Suspend-to-Disk).
 404  *
 405  *      store() accepts one of those strings, translates it into the
 406  *      proper enumerated value, and initiates a suspend transition.
 407  */
 408
 409 static ssize_t state_show(struct kobject *kobj, struct kobj_attribute *attr,
 410                           char *buf)
 411 {
 412         char *s = buf;
 413 #ifdef CONFIG_SUSPEND
 414         int i;
 415
 416         for (i = 0; i < PM_SUSPEND_MAX; i++) {
 417                 if (pm_states[i] && valid_state(i))
 418                         s += sprintf(s,"%s ", pm_states[i]);
 419         }
 420 #endif
 421 #ifdef CONFIG_HIBERNATION
 422         s += sprintf(s, "%s\n", "disk");
 423 #else
 424         if (s != buf)
 425                 /* convert the last space to a newline */
 426                 *(s-1) = '\n';
 427 #endif
 428         return (s - buf);
 429 }
 430
 431 static ssize_t state_store(struct kobject *kobj, struct kobj_attribute *attr,
 432                            const char *buf, size_t n)
 433 {
 434 #ifdef CONFIG_SUSPEND
 435         suspend_state_t state = PM_SUSPEND_STANDBY;
 436         const char * const *s;
 437 #endif
 438         char *p;
 439         int len;
 440         int error = -EINVAL;
 441
 442         p = memchr(buf, '\n', n);
 443         len = p ? p - buf : n;
 444
 445         /* First, check if we are requested to hibernate */
 446         if (len == 4 && !strncmp(buf, "disk", len)) {
 447                 error = hibernate();
 448   goto Exit;
 449         }
 450
 451 #ifdef CONFIG_SUSPEND
 452         for (s = &pm_states[state]; state < PM_SUSPEND_MAX; s++, state++) {
 453                 if (*s && len == strlen(*s) && !strncmp(buf, *s, len))
 454                         break;
 455         }
 456         if (state < PM_SUSPEND_MAX && *s)
 457                 error = enter_state(state);
 458 #endif
 459
 460  Exit:
 461         return error ? error : n;
 462 }
 463
 464 power_attr(state);
 465
 466 #ifdef CONFIG_PM_TRACE
 467 int pm_trace_enabled;
 468
 469 static ssize_t pm_trace_show(struct kobject *kobj, struct kobj_attribute *attr,
 470                              char *buf)
 471 {
 472         return sprintf(buf, "%d\n", pm_trace_enabled);
 473 }
 474
 475 static ssize_t
 476 pm_trace_store(struct kobject *kobj, struct kobj_attribute *attr,
 477                const char *buf, size_t n)
 478 {
 479         int val;
 480
 481         if (sscanf(buf, "%d", &val) == 1) {
 482                 pm_trace_enabled = !!val;
 483                 return n;
 484         }
 485         return -EINVAL;
 486 }
 487
 488 power_attr(pm_trace);
 489 #endif /* CONFIG_PM_TRACE */
 490
 491 static struct attribute * g[] = {
 492         &state_attr.attr,
 493 #ifdef CONFIG_PM_TRACE
 494         &pm_trace_attr.attr,
 495 #endif
 496 #ifdef CONFIG_PM_DEBUG
 497         &pm_test_attr.attr,
 498 #endif
 499         NULL,
 500 };
 501
 502 static struct attribute_group attr_group = {
 503         .attrs = g,
 504 };
 505
 506
 507 static int __init pm_init(void)
 508 {
 509         power_kobj = kobject_create_and_add("power", NULL);
 510         if (!power_kobj)
 511                 return -ENOMEM;
 512         return sysfs_create_group(power_kobj, &attr_group);
 513 }
 514
 515 core_initcall(pm_init);