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