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