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         pm_prepare_console();
 179
 180         error = pm_notifier_call_chain(PM_SUSPEND_PREPARE);
 181         if (error)
 182                 goto Finish;
 183
 184         if (suspend_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         suspend_thaw_processes();
 203  Finish:
 204         pm_notifier_call_chain(PM_POST_SUSPEND);
 205         pm_restore_console();
 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         device_pm_lock();
 232         arch_suspend_disable_irqs();
 233         BUG_ON(!irqs_disabled());
 234
 235         if ((error = device_power_down(PMSG_SUSPEND))) {
 236                 printk(KERN_ERR "PM: 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(PMSG_RESUME);
 244  Done:
 245         arch_suspend_enable_irqs();
 246         BUG_ON(irqs_disabled());
 247         device_pm_unlock();
 248         return error;
 249 }
 250
 251 /**
 252  *      suspend_devices_and_enter - suspend devices and enter the desired system
 253  *                                  sleep state.
 254  *      @state:           state to enter
 255  */
 256 int suspend_devices_and_enter(suspend_state_t state)
 257 {
 258         int error;
 259
 260         if (!suspend_ops)
 261                 return -ENOSYS;
 262
 263         if (suspend_ops->begin) {
 264                 error = suspend_ops->begin(state);
 265                 if (error)
 266                         goto Close;
 267         }
 268         suspend_console();
 269         error = device_suspend(PMSG_SUSPEND);
 270         if (error) {
 271                 printk(KERN_ERR "PM: Some devices failed to suspend\n");
 272                 goto Resume_console;
 273         }
 274
 275         if (suspend_test(TEST_DEVICES))
 276                 goto Resume_devices;
 277
 278         if (suspend_ops->prepare) {
 279                 error = suspend_ops->prepare();
 280                 if (error)
 281                         goto Resume_devices;
 282         }
 283
 284         if (suspend_test(TEST_PLATFORM))
 285                 goto Finish;
 286
 287         error = disable_nonboot_cpus();
 288         if (!error && !suspend_test(TEST_CPUS))
 289                 suspend_enter(state);
 290
 291         enable_nonboot_cpus();
 292  Finish:
 293         if (suspend_ops->finish)
 294                 suspend_ops->finish();
 295  Resume_devices:
 296         device_resume(PMSG_RESUME);
 297  Resume_console:
 298         resume_console();
 299  Close:
 300         if (suspend_ops->end)
 301                 suspend_ops->end();
 302         return error;
 303 }
 304
 305 /**
 306  *      suspend_finish - Do final work before exiting suspend sequence.
 307  *
 308  *      Call platform code to clean up, restart processes, and free the
 309  *      console that we've allocated. This is not called for suspend-to-disk.
 310  */
 311 static void suspend_finish(void)
 312 {
 313         suspend_thaw_processes();
 314         pm_notifier_call_chain(PM_POST_SUSPEND);
 315         pm_restore_console();
 316 }
 317
 318
 319
 320
 321 static const char * const pm_states[PM_SUSPEND_MAX] = {
 322         [PM_SUSPEND_STANDBY]    = "standby",
 323         [PM_SUSPEND_MEM]        = "mem",
 324 };
 325
 326 static inline int valid_state(suspend_state_t state)
 327 {
 328         /* All states need lowlevel support and need to be valid
 329          * to the lowlevel implementation, no valid callback
 330          * implies that none are valid. */
 331         if (!suspend_ops || !suspend_ops->valid || !suspend_ops->valid(state))
 332                 return 0;
 333         return 1;
 334 }
 335
 336
 337 /**
 338  *      enter_state - Do common work of entering low-power state.
 339  *      @state:         pm_state structure for state we're entering.
 340  *
 341  *      Make sure we're the only ones trying to enter a sleep state. Fail
 342  *      if someone has beat us to it, since we don't want anything weird to
 343  *      happen when we wake up.
 344  *      Then, do the setup for suspend, enter the state, and cleaup (after
 345  *      we've woken up).
 346  */
 347 static int enter_state(suspend_state_t state)
 348 {
 349         int error;
 350
 351         if (!valid_state(state))
 352                 return -ENODEV;
 353
 354         if (!mutex_trylock(&pm_mutex))
 355                 return -EBUSY;
 356
 357         printk(KERN_INFO "PM: Syncing filesystems ... ");
 358         sys_sync();
 359         printk("done.\n");
 360
 361         pr_debug("PM: Preparing system for %s sleep\n", pm_states[state]);
 362         error = suspend_prepare();
 363         if (error)
 364                 goto Unlock;
 365
 366         if (suspend_test(TEST_FREEZER))
 367                 goto Finish;
 368
 369         pr_debug("PM: Entering %s sleep\n", pm_states[state]);
 370         error = suspend_devices_and_enter(state);
 371
 372  Finish:
 373         pr_debug("PM: Finishing wakeup.\n");
 374         suspend_finish();
 375  Unlock:
 376         mutex_unlock(&pm_mutex);
 377         return error;
 378 }
 379
 380
 381 /**
 382  *      pm_suspend - Externally visible function for suspending system.
 383  *      @state:         Enumerated value of state to enter.
 384  *
 385  *      Determine whether or not value is within range, get state
 386  *      structure, and enter (above).
 387  */
 388
 389 int pm_suspend(suspend_state_t state)
 390 {
 391         if (state > PM_SUSPEND_ON && state <= PM_SUSPEND_MAX)
 392                 return enter_state(state);
 393         return -EINVAL;
 394 }
 395
 396 EXPORT_SYMBOL(pm_suspend);
 397
 398 #endif /* CONFIG_SUSPEND */
 399
 400 struct kobject *power_kobj;
 401
 402 /**
 403  *      state - control system power state.
 404  *
 405  *      show() returns what states are supported, which is hard-coded to
 406  *      'standby' (Power-On Suspend), 'mem' (Suspend-to-RAM), and
 407  *      'disk' (Suspend-to-Disk).
 408  *
 409  *      store() accepts one of those strings, translates it into the
 410  *      proper enumerated value, and initiates a suspend transition.
 411  */
 412
 413 static ssize_t state_show(struct kobject *kobj, struct kobj_attribute *attr,
 414                           char *buf)
 415 {
 416         char *s = buf;
 417 #ifdef CONFIG_SUSPEND
 418         int i;
 419
 420         for (i = 0; i < PM_SUSPEND_MAX; i++) {
 421                 if (pm_states[i] && valid_state(i))
 422                         s += sprintf(s,"%s ", pm_states[i]);
 423         }
 424 #endif
 425 #ifdef CONFIG_HIBERNATION
 426         s += sprintf(s, "%s\n", "disk");
 427 #else
 428         if (s != buf)
 429                 /* convert the last space to a newline */
 430                 *(s-1) = '\n';
 431 #endif
 432         return (s - buf);
 433 }
 434
 435 static ssize_t state_store(struct kobject *kobj, struct kobj_attribute *attr,
 436                            const char *buf, size_t n)
 437 {
 438 #ifdef CONFIG_SUSPEND
 439         suspend_state_t state = PM_SUSPEND_STANDBY;
 440         const char * const *s;
 441 #endif
 442         char *p;
 443         int len;
 444         int error = -EINVAL;
 445
 446         p = memchr(buf, '\n', n);
 447         len = p ? p - buf : n;
 448
 449         /* First, check if we are requested to hibernate */
 450         if (len == 4 && !strncmp(buf, "disk", len)) {
 451                 error = hibernate();
 452   goto Exit;
 453         }
 454
 455 #ifdef CONFIG_SUSPEND
 456         for (s = &pm_states[state]; state < PM_SUSPEND_MAX; s++, state++) {
 457                 if (*s && len == strlen(*s) && !strncmp(buf, *s, len))
 458                         break;
 459         }
 460         if (state < PM_SUSPEND_MAX && *s)
 461                 error = enter_state(state);
 462 #endif
 463
 464  Exit:
 465         return error ? error : n;
 466 }
 467
 468 power_attr(state);
 469
 470 #ifdef CONFIG_PM_TRACE
 471 int pm_trace_enabled;
 472
 473 static ssize_t pm_trace_show(struct kobject *kobj, struct kobj_attribute *attr,
 474                              char *buf)
 475 {
 476         return sprintf(buf, "%d\n", pm_trace_enabled);
 477 }
 478
 479 static ssize_t
 480 pm_trace_store(struct kobject *kobj, struct kobj_attribute *attr,
 481                const char *buf, size_t n)
 482 {
 483         int val;
 484
 485         if (sscanf(buf, "%d", &val) == 1) {
 486                 pm_trace_enabled = !!val;
 487                 return n;
 488         }
 489         return -EINVAL;
 490 }
 491
 492 power_attr(pm_trace);
 493 #endif /* CONFIG_PM_TRACE */
 494
 495 static struct attribute * g[] = {
 496         &state_attr.attr,
 497 #ifdef CONFIG_PM_TRACE
 498         &pm_trace_attr.attr,
 499 #endif
 500 #if defined(CONFIG_PM_SLEEP) && defined(CONFIG_PM_DEBUG)
 501         &pm_test_attr.attr,
 502 #endif
 503         NULL,
 504 };
 505
 506 static struct attribute_group attr_group = {
 507         .attrs = g,
 508 };
 509
 510
 511 static int __init pm_init(void)
 512 {
 513         power_kobj = kobject_create_and_add("power", NULL);
 514         if (!power_kobj)
 515                 return -ENOMEM;
 516         return sysfs_create_group(power_kobj, &attr_group);
 517 }
 518
 519 core_initcall(pm_init);