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