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_SUSPEND
  59
  60 #ifdef CONFIG_PM_DEBUG
  61 int pm_test_level = TEST_NONE;
  62
  63 static int suspend_test(int level)
  64 {
  65         if (pm_test_level == level) {
  66                 printk(KERN_INFO "suspend debug: Waiting for 5 seconds.\n");
  67                 mdelay(5000);
  68                 return 1;
  69         }
  70         return 0;
  71 }
  72
  73 static const char * const pm_tests[__TEST_AFTER_LAST] = {
  74         [TEST_NONE] = "none",
  75         [TEST_CORE] = "core",
  76         [TEST_CPUS] = "processors",
  77         [TEST_PLATFORM] = "platform",
  78         [TEST_DEVICES] = "devices",
  79         [TEST_FREEZER] = "freezer",
  80 };
  81
  82 static ssize_t pm_test_show(struct kobject *kobj, struct kobj_attribute *attr,
  83                                 char *buf)
  84 {
  85         char *s = buf;
  86         int level;
  87
  88         for (level = TEST_FIRST; level <= TEST_MAX; level++)
  89                 if (pm_tests[level]) {
  90                         if (level == pm_test_level)
  91                                 s += sprintf(s, "[%s] ", pm_tests[level]);
  92                         else
  93                                 s += sprintf(s, "%s ", pm_tests[level]);
  94                 }
  95
  96         if (s != buf)
  97                 /* convert the last space to a newline */
  98                 *(s-1) = '\n';
  99
 100         return (s - buf);
 101 }
 102
 103 static ssize_t pm_test_store(struct kobject *kobj, struct kobj_attribute *attr,
 104                                 const char *buf, size_t n)
 105 {
 106         const char * const *s;
 107         int level;
 108         char *p;
 109         int len;
 110         int error = -EINVAL;
 111
 112         p = memchr(buf, '\n', n);
 113         len = p ? p - buf : n;
 114
 115         mutex_lock(&pm_mutex);
 116
 117         level = TEST_FIRST;
 118         for (s = &pm_tests[level]; level <= TEST_MAX; s++, level++)
 119                 if (*s && len == strlen(*s) && !strncmp(buf, *s, len)) {
 120                         pm_test_level = level;
 121                         error = 0;
 122                         break;
 123                 }
 124
 125         mutex_unlock(&pm_mutex);
 126
 127         return error ? error : n;
 128 }
 129
 130 power_attr(pm_test);
 131 #else /* !CONFIG_PM_DEBUG */
 132 static inline int suspend_test(int level) { return 0; }
 133 #endif /* !CONFIG_PM_DEBUG */
 134
 135
 136 #ifdef CONFIG_SUSPEND
 137
 138 /* This is just an arbitrary number */
 139 #define FREE_PAGE_NUMBER (100)
 140
 141 static struct platform_suspend_ops *suspend_ops;
 142
 143 /**
 144  *      suspend_set_ops - Set the global suspend method table.
 145  *      @ops:   Pointer to ops structure.
 146  */
 147
 148 void suspend_set_ops(struct platform_suspend_ops *ops)
 149 {
 150         mutex_lock(&pm_mutex);
 151         suspend_ops = ops;
 152         mutex_unlock(&pm_mutex);
 153 }
 154
 155 /**
 156  * suspend_valid_only_mem - generic memory-only valid callback
 157  *
 158  * Platform drivers that implement mem suspend only and only need
 159  * to check for that in their .valid callback can use this instead
 160  * of rolling their own .valid callback.
 161  */
 162 int suspend_valid_only_mem(suspend_state_t state)
 163 {
 164         return state == PM_SUSPEND_MEM;
 165 }
 166
 167 /**
 168  *      suspend_prepare - Do prep work before entering low-power state.
 169  *
 170  *      This is common code that is called for each state that we're entering.
 171  *      Run suspend notifiers, allocate a console and stop all processes.
 172  */
 173 static int suspend_prepare(void)
 174 {
 175         int error;
 176         unsigned int free_pages;
 177
 178         if (!suspend_ops || !suspend_ops->enter)
 179                 return -EPERM;
 180
 181         error = pm_notifier_call_chain(PM_SUSPEND_PREPARE);
 182         if (error)
 183                 goto Finish;
 184
 185         pm_prepare_console();
 186
 187         if (freeze_processes()) {
 188                 error = -EAGAIN;
 189                 goto Thaw;
 190         }
 191
 192         free_pages = global_page_state(NR_FREE_PAGES);
 193         if (free_pages < FREE_PAGE_NUMBER) {
 194                 pr_debug("PM: free some memory\n");
 195                 shrink_all_memory(FREE_PAGE_NUMBER - free_pages);
 196                 if (nr_free_pages() < FREE_PAGE_NUMBER) {
 197                         error = -ENOMEM;
 198                         printk(KERN_ERR "PM: No enough memory\n");
 199                 }
 200         }
 201         if (!error)
 202                 return 0;
 203
 204  Thaw:
 205         thaw_processes();
 206         pm_restore_console();
 207  Finish:
 208         pm_notifier_call_chain(PM_POST_SUSPEND);
 209         return error;
 210 }
 211
 212 /* default implementation */
 213 void __attribute__ ((weak)) arch_suspend_disable_irqs(void)
 214 {
 215         local_irq_disable();
 216 }
 217
 218 /* default implementation */
 219 void __attribute__ ((weak)) arch_suspend_enable_irqs(void)
 220 {
 221         local_irq_enable();
 222 }
 223
 224 /**
 225  *      suspend_enter - enter the desired system sleep state.
 226  *      @state:         state to enter
 227  *
 228  *      This function should be called after devices have been suspended.
 229  */
 230 static int suspend_enter(suspend_state_t state)
 231 {
 232         int error = 0;
 233
 234         arch_suspend_disable_irqs();
 235         BUG_ON(!irqs_disabled());
 236
 237         if ((error = device_power_down(PMSG_SUSPEND))) {
 238                 printk(KERN_ERR "PM: Some devices failed to power down\n");
 239                 goto Done;
 240         }
 241
 242         if (!suspend_test(TEST_CORE))
 243                 error = suspend_ops->enter(state);
 244
 245         device_power_up();
 246  Done:
 247         arch_suspend_enable_irqs();
 248         BUG_ON(irqs_disabled());
 249         return error;
 250 }
 251
 252 /**
 253  *      suspend_devices_and_enter - suspend devices and enter the desired system
 254  *                                  sleep state.
 255  *      @state:           state to enter
 256  */
 257 int suspend_devices_and_enter(suspend_state_t state)
 258 {
 259         int error;
 260
 261         if (!suspend_ops)
 262                 return -ENOSYS;
 263
 264         if (suspend_ops->set_target) {
 265                 error = suspend_ops->set_target(state);
 266                 if (error)
 267                         return error;
 268         }
 269         suspend_console();
 270         error = device_suspend(PMSG_SUSPEND);
 271         if (error) {
 272                 printk(KERN_ERR "PM: Some devices failed to suspend\n");
 273                 goto Resume_console;
 274         }
 275
 276         if (suspend_test(TEST_DEVICES))
 277                 goto Resume_devices;
 278
 279         if (suspend_ops->prepare) {
 280                 error = suspend_ops->prepare();
 281                 if (error)
 282                         goto Resume_devices;
 283         }
 284
 285         if (suspend_test(TEST_PLATFORM))
 286                 goto Finish;
 287
 288         error = disable_nonboot_cpus();
 289         if (!error && !suspend_test(TEST_CPUS))
 290                 suspend_enter(state);
 291
 292         enable_nonboot_cpus();
 293  Finish:
 294         if (suspend_ops->finish)
 295                 suspend_ops->finish();
 296  Resume_devices:
 297         device_resume();
 298  Resume_console:
 299         resume_console();
 300         return error;
 301 }
 302
 303 /**
 304  *      suspend_finish - Do final work before exiting suspend sequence.
 305  *
 306  *      Call platform code to clean up, restart processes, and free the
 307  *      console that we've allocated. This is not called for suspend-to-disk.
 308  */
 309 static void suspend_finish(void)
 310 {
 311         thaw_processes();
 312         pm_restore_console();
 313         pm_notifier_call_chain(PM_POST_SUSPEND);
 314 }
 315
 316
 317
 318
 319 static const char * const pm_states[PM_SUSPEND_MAX] = {
 320         [PM_SUSPEND_STANDBY]    = "standby",
 321         [PM_SUSPEND_MEM]        = "mem",
 322 };
 323
 324 static inline int valid_state(suspend_state_t state)
 325 {
 326         /* All states need lowlevel support and need to be valid
 327          * to the lowlevel implementation, no valid callback
 328          * implies that none are valid. */
 329         if (!suspend_ops || !suspend_ops->valid || !suspend_ops->valid(state))
 330                 return 0;
 331         return 1;
 332 }
 333
 334
 335 /**
 336  *      enter_state - Do common work of entering low-power state.
 337  *      @state:         pm_state structure for state we're entering.
 338  *
 339  *      Make sure we're the only ones trying to enter a sleep state. Fail
 340  *      if someone has beat us to it, since we don't want anything weird to
 341  *      happen when we wake up.
 342  *      Then, do the setup for suspend, enter the state, and cleaup (after
 343  *      we've woken up).
 344  */
 345 static int enter_state(suspend_state_t state)
 346 {
 347         int error;
 348
 349         if (!valid_state(state))
 350                 return -ENODEV;
 351
 352         if (!mutex_trylock(&pm_mutex))
 353                 return -EBUSY;
 354
 355         printk(KERN_INFO "PM: Syncing filesystems ... ");
 356         sys_sync();
 357         printk("done.\n");
 358
 359         pr_debug("PM: Preparing system for %s sleep\n", pm_states[state]);
 360         error = suspend_prepare();
 361         if (error)
 362                 goto Unlock;
 363
 364         if (suspend_test(TEST_FREEZER))
 365                 goto Finish;
 366
 367         pr_debug("PM: Entering %s sleep\n", pm_states[state]);
 368         error = suspend_devices_and_enter(state);
 369
 370  Finish:
 371         pr_debug("PM: Finishing wakeup.\n");
 372         suspend_finish();
 373  Unlock:
 374         mutex_unlock(&pm_mutex);
 375         return error;
 376 }
 377
 378
 379 /**
 380  *      pm_suspend - Externally visible function for suspending system.
 381  *      @state:         Enumerated value of state to enter.
 382  *
 383  *      Determine whether or not value is within range, get state
 384  *      structure, and enter (above).
 385  */
 386
 387 int pm_suspend(suspend_state_t state)
 388 {
 389         if (state > PM_SUSPEND_ON && state <= PM_SUSPEND_MAX)
 390                 return enter_state(state);
 391         return -EINVAL;
 392 }
 393
 394 EXPORT_SYMBOL(pm_suspend);
 395
 396 #endif /* CONFIG_SUSPEND */
 397
 398 struct kobject *power_kobj;
 399
 400 /**
 401  *      state - control system power state.
 402  *
 403  *      show() returns what states are supported, which is hard-coded to
 404  *      'standby' (Power-On Suspend), 'mem' (Suspend-to-RAM), and
 405  *      'disk' (Suspend-to-Disk).
 406  *
 407  *      store() accepts one of those strings, translates it into the
 408  *      proper enumerated value, and initiates a suspend transition.
 409  */
 410
 411 static ssize_t state_show(struct kobject *kobj, struct kobj_attribute *attr,
 412                           char *buf)
 413 {
 414         char *s = buf;
 415 #ifdef CONFIG_SUSPEND
 416         int i;
 417
 418         for (i = 0; i < PM_SUSPEND_MAX; i++) {
 419                 if (pm_states[i] && valid_state(i))
 420                         s += sprintf(s,"%s ", pm_states[i]);
 421         }
 422 #endif
 423 #ifdef CONFIG_HIBERNATION
 424         s += sprintf(s, "%s\n", "disk");
 425 #else
 426         if (s != buf)
 427                 /* convert the last space to a newline */
 428                 *(s-1) = '\n';
 429 #endif
 430         return (s - buf);
 431 }
 432
 433 static ssize_t state_store(struct kobject *kobj, struct kobj_attribute *attr,
 434                            const char *buf, size_t n)
 435 {
 436 #ifdef CONFIG_SUSPEND
 437         suspend_state_t state = PM_SUSPEND_STANDBY;
 438         const char * const *s;
 439 #endif
 440         char *p;
 441         int len;
 442         int error = -EINVAL;
 443
 444         p = memchr(buf, '\n', n);
 445         len = p ? p - buf : n;
 446
 447         /* First, check if we are requested to hibernate */
 448         if (len == 4 && !strncmp(buf, "disk", len)) {
 449                 error = hibernate();
 450   goto Exit;
 451         }
 452
 453 #ifdef CONFIG_SUSPEND
 454         for (s = &pm_states[state]; state < PM_SUSPEND_MAX; s++, state++) {
 455                 if (*s && len == strlen(*s) && !strncmp(buf, *s, len))
 456                         break;
 457         }
 458         if (state < PM_SUSPEND_MAX && *s)
 459                 error = enter_state(state);
 460 #endif
 461
 462  Exit:
 463         return error ? error : n;
 464 }
 465
 466 power_attr(state);
 467
 468 #ifdef CONFIG_PM_TRACE
 469 int pm_trace_enabled;
 470
 471 static ssize_t pm_trace_show(struct kobject *kobj, struct kobj_attribute *attr,
 472                              char *buf)
 473 {
 474         return sprintf(buf, "%d\n", pm_trace_enabled);
 475 }
 476
 477 static ssize_t
 478 pm_trace_store(struct kobject *kobj, struct kobj_attribute *attr,
 479                const char *buf, size_t n)
 480 {
 481         int val;
 482
 483         if (sscanf(buf, "%d", &val) == 1) {
 484                 pm_trace_enabled = !!val;
 485                 return n;
 486         }
 487         return -EINVAL;
 488 }
 489
 490 power_attr(pm_trace);
 491 #endif /* CONFIG_PM_TRACE */
 492
 493 static struct attribute * g[] = {
 494         &state_attr.attr,
 495 #ifdef CONFIG_PM_TRACE
 496         &pm_trace_attr.attr,
 497 #endif
 498 #ifdef CONFIG_PM_DEBUG
 499         &pm_test_attr.attr,
 500 #endif
 501         NULL,
 502 };
 503
 504 static struct attribute_group attr_group = {
 505         .attrs = g,
 506 };
 507
 508
 509 static int __init pm_init(void)
 510 {
 511         power_kobj = kobject_create_and_add("power", NULL);
 512         if (!power_kobj)
 513                 return -ENOMEM;
 514         return sysfs_create_group(power_kobj, &attr_group);
 515 }
 516
 517 core_initcall(pm_init);