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