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
  24 #include "power.h"
  25
  26 BLOCKING_NOTIFIER_HEAD(pm_chain_head);
  27
  28 /*This is just an arbitrary number */
  29 #define FREE_PAGE_NUMBER (100)
  30
  31 DEFINE_MUTEX(pm_mutex);
  32
  33 struct pm_ops *pm_ops;
  34
  35 /**
  36  *      pm_set_ops - Set the global power method table.
  37  *      @ops:   Pointer to ops structure.
  38  */
  39
  40 void pm_set_ops(struct pm_ops * ops)
  41 {
  42         mutex_lock(&pm_mutex);
  43         pm_ops = ops;
  44         mutex_unlock(&pm_mutex);
  45 }
  46
  47 /**
  48  * pm_valid_only_mem - generic memory-only valid callback
  49  *
  50  * pm_ops drivers that implement mem suspend only and only need
  51  * to check for that in their .valid callback can use this instead
  52  * of rolling their own .valid callback.
  53  */
  54 int pm_valid_only_mem(suspend_state_t state)
  55 {
  56         return state == PM_SUSPEND_MEM;
  57 }
  58
  59
  60 static inline void pm_finish(suspend_state_t state)
  61 {
  62         if (pm_ops->finish)
  63                 pm_ops->finish(state);
  64 }
  65
  66 /**
  67  *      suspend_prepare - Do prep work before entering low-power state.
  68  *
  69  *      This is common code that is called for each state that we're entering.
  70  *      Run suspend notifiers, allocate a console and stop all processes.
  71  */
  72 static int suspend_prepare(void)
  73 {
  74         int error;
  75         unsigned int free_pages;
  76
  77         if (!pm_ops || !pm_ops->enter)
  78                 return -EPERM;
  79
  80         error = pm_notifier_call_chain(PM_SUSPEND_PREPARE);
  81         if (error)
  82                 goto Finish;
  83
  84         pm_prepare_console();
  85
  86         if (freeze_processes()) {
  87                 error = -EAGAIN;
  88                 goto Thaw;
  89         }
  90
  91         free_pages = global_page_state(NR_FREE_PAGES);
  92         if (free_pages < FREE_PAGE_NUMBER) {
  93                 pr_debug("PM: free some memory\n");
  94                 shrink_all_memory(FREE_PAGE_NUMBER - free_pages);
  95                 if (nr_free_pages() < FREE_PAGE_NUMBER) {
  96                         error = -ENOMEM;
  97                         printk(KERN_ERR "PM: No enough memory\n");
  98                 }
  99         }
 100         if (!error)
 101                 return 0;
 102
 103  Thaw:
 104         thaw_processes();
 105         pm_restore_console();
 106  Finish:
 107         pm_notifier_call_chain(PM_POST_SUSPEND);
 108         return error;
 109 }
 110
 111 /* default implementation */
 112 void __attribute__ ((weak)) arch_suspend_disable_irqs(void)
 113 {
 114         local_irq_disable();
 115 }
 116
 117 /* default implementation */
 118 void __attribute__ ((weak)) arch_suspend_enable_irqs(void)
 119 {
 120         local_irq_enable();
 121 }
 122
 123 /**
 124  *      suspend_enter - enter the desired system sleep state.
 125  *      @state:         state to enter
 126  *
 127  *      This function should be called after devices have been suspended.
 128  */
 129 int suspend_enter(suspend_state_t state)
 130 {
 131         int error = 0;
 132
 133         arch_suspend_disable_irqs();
 134         BUG_ON(!irqs_disabled());
 135
 136         if ((error = device_power_down(PMSG_SUSPEND))) {
 137                 printk(KERN_ERR "Some devices failed to power down\n");
 138                 goto Done;
 139         }
 140         error = pm_ops->enter(state);
 141         device_power_up();
 142  Done:
 143         arch_suspend_enable_irqs();
 144         BUG_ON(irqs_disabled());
 145         return error;
 146 }
 147
 148 /**
 149  *      suspend_devices_and_enter - suspend devices and enter the desired system sleep
 150  *                        state.
 151  *      @state:           state to enter
 152  */
 153 int suspend_devices_and_enter(suspend_state_t state)
 154 {
 155         int error;
 156
 157         if (!pm_ops)
 158                 return -ENOSYS;
 159
 160         if (pm_ops->set_target) {
 161                 error = pm_ops->set_target(state);
 162                 if (error)
 163                         return error;
 164         }
 165         suspend_console();
 166         error = device_suspend(PMSG_SUSPEND);
 167         if (error) {
 168                 printk(KERN_ERR "Some devices failed to suspend\n");
 169                 goto Resume_console;
 170         }
 171         if (pm_ops->prepare) {
 172                 error = pm_ops->prepare(state);
 173                 if (error)
 174                         goto Resume_devices;
 175         }
 176         error = disable_nonboot_cpus();
 177         if (!error)
 178                 suspend_enter(state);
 179
 180         enable_nonboot_cpus();
 181         pm_finish(state);
 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 (!pm_ops || !pm_ops->valid || !pm_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         if (!mutex_trylock(&pm_mutex))
 238                 return -EBUSY;
 239
 240         pr_debug("PM: Preparing system for %s sleep\n", pm_states[state]);
 241         if ((error = suspend_prepare()))
 242                 goto Unlock;
 243
 244         pr_debug("PM: Entering %s sleep\n", pm_states[state]);
 245         error = suspend_devices_and_enter(state);
 246
 247         pr_debug("PM: Finishing wakeup.\n");
 248         suspend_finish();
 249  Unlock:
 250         mutex_unlock(&pm_mutex);
 251         return error;
 252 }
 253
 254
 255 /**
 256  *      pm_suspend - Externally visible function for suspending system.
 257  *      @state:         Enumerated value of state to enter.
 258  *
 259  *      Determine whether or not value is within range, get state
 260  *      structure, and enter (above).
 261  */
 262
 263 int pm_suspend(suspend_state_t state)
 264 {
 265         if (state > PM_SUSPEND_ON && state <= PM_SUSPEND_MAX)
 266                 return enter_state(state);
 267         return -EINVAL;
 268 }
 269
 270 EXPORT_SYMBOL(pm_suspend);
 271
 272 decl_subsys(power,NULL,NULL);
 273
 274
 275 /**
 276  *      state - control system power state.
 277  *
 278  *      show() returns what states are supported, which is hard-coded to
 279  *      'standby' (Power-On Suspend), 'mem' (Suspend-to-RAM), and
 280  *      'disk' (Suspend-to-Disk).
 281  *
 282  *      store() accepts one of those strings, translates it into the
 283  *      proper enumerated value, and initiates a suspend transition.
 284  */
 285
 286 static ssize_t state_show(struct kset *kset, char *buf)
 287 {
 288         int i;
 289         char * s = buf;
 290
 291         for (i = 0; i < PM_SUSPEND_MAX; i++) {
 292                 if (pm_states[i] && valid_state(i))
 293                         s += sprintf(s,"%s ", pm_states[i]);
 294         }
 295 #ifdef CONFIG_SOFTWARE_SUSPEND
 296         s += sprintf(s, "%s\n", "disk");
 297 #else
 298         if (s != buf)
 299                 /* convert the last space to a newline */
 300                 *(s-1) = '\n';
 301 #endif
 302         return (s - buf);
 303 }
 304
 305 static ssize_t state_store(struct kset *kset, const char *buf, size_t n)
 306 {
 307         suspend_state_t state = PM_SUSPEND_STANDBY;
 308         const char * const *s;
 309         char *p;
 310         int error;
 311         int len;
 312
 313         p = memchr(buf, '\n', n);
 314         len = p ? p - buf : n;
 315
 316         /* First, check if we are requested to hibernate */
 317         if (len == 4 && !strncmp(buf, "disk", len)) {
 318                 error = hibernate();
 319                 return error ? error : n;
 320         }
 321
 322         for (s = &pm_states[state]; state < PM_SUSPEND_MAX; s++, state++) {
 323                 if (*s && len == strlen(*s) && !strncmp(buf, *s, len))
 324                         break;
 325         }
 326         if (state < PM_SUSPEND_MAX && *s)
 327                 error = enter_state(state);
 328         else
 329                 error = -EINVAL;
 330         return error ? error : n;
 331 }
 332
 333 power_attr(state);
 334
 335 #ifdef CONFIG_PM_TRACE
 336 int pm_trace_enabled;
 337
 338 static ssize_t pm_trace_show(struct kset *kset, char *buf)
 339 {
 340         return sprintf(buf, "%d\n", pm_trace_enabled);
 341 }
 342
 343 static ssize_t
 344 pm_trace_store(struct kset *kset, const char *buf, size_t n)
 345 {
 346         int val;
 347
 348         if (sscanf(buf, "%d", &val) == 1) {
 349                 pm_trace_enabled = !!val;
 350                 return n;
 351         }
 352         return -EINVAL;
 353 }
 354
 355 power_attr(pm_trace);
 356
 357 static struct attribute * g[] = {
 358         &state_attr.attr,
 359         &pm_trace_attr.attr,
 360         NULL,
 361 };
 362 #else
 363 static struct attribute * g[] = {
 364         &state_attr.attr,
 365         NULL,
 366 };
 367 #endif /* CONFIG_PM_TRACE */
 368
 369 static struct attribute_group attr_group = {
 370         .attrs = g,
 371 };
 372
 373
 374 static int __init pm_init(void)
 375 {
 376         int error = subsystem_register(&power_subsys);
 377         if (!error)
 378                 error = sysfs_create_group(&power_subsys.kobj,&attr_group);
 379         return error;
 380 }
 381
 382 core_initcall(pm_init);