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