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 DEFINE_MUTEX(pm_mutex);
  29
  30 #ifdef CONFIG_SUSPEND
  31
  32 /* This is just an arbitrary number */
  33 #define FREE_PAGE_NUMBER (100)
  34
  35 struct pm_ops *pm_ops;
  36
  37 /**
  38  *      pm_set_ops - Set the global power method table.
  39  *      @ops:   Pointer to ops structure.
  40  */
  41
  42 void pm_set_ops(struct pm_ops * ops)
  43 {
  44         mutex_lock(&pm_mutex);
  45         pm_ops = ops;
  46         mutex_unlock(&pm_mutex);
  47 }
  48
  49 /**
  50  * pm_valid_only_mem - generic memory-only valid callback
  51  *
  52  * pm_ops drivers that implement mem suspend only and only need
  53  * to check for that in their .valid callback can use this instead
  54  * of rolling their own .valid callback.
  55  */
  56 int pm_valid_only_mem(suspend_state_t state)
  57 {
  58         return state == PM_SUSPEND_MEM;
  59 }
  60
  61
  62 static inline void pm_finish(suspend_state_t state)
  63 {
  64         if (pm_ops->finish)
  65                 pm_ops->finish(state);
  66 }
  67
  68 /**
  69  *      suspend_prepare - Do prep work before entering low-power state.
  70  *
  71  *      This is common code that is called for each state that we're entering.
  72  *      Run suspend notifiers, allocate a console and stop all processes.
  73  */
  74 static int suspend_prepare(void)
  75 {
  76         int error;
  77         unsigned int free_pages;
  78
  79         if (!pm_ops || !pm_ops->enter)
  80                 return -EPERM;
  81
  82         error = pm_notifier_call_chain(PM_SUSPEND_PREPARE);
  83         if (error)
  84                 goto Finish;
  85
  86         pm_prepare_console();
  87
  88         if (freeze_processes()) {
  89                 error = -EAGAIN;
  90                 goto Thaw;
  91         }
  92
  93         free_pages = global_page_state(NR_FREE_PAGES);
  94         if (free_pages < FREE_PAGE_NUMBER) {
  95                 pr_debug("PM: free some memory\n");
  96                 shrink_all_memory(FREE_PAGE_NUMBER - free_pages);
  97                 if (nr_free_pages() < FREE_PAGE_NUMBER) {
  98                         error = -ENOMEM;
  99                         printk(KERN_ERR "PM: No enough memory\n");
 100                 }
 101         }
 102         if (!error)
 103                 return 0;
 104
 105  Thaw:
 106         thaw_processes();
 107         pm_restore_console();
 108  Finish:
 109         pm_notifier_call_chain(PM_POST_SUSPEND);
 110         return error;
 111 }
 112
 113 /* default implementation */
 114 void __attribute__ ((weak)) arch_suspend_disable_irqs(void)
 115 {
 116         local_irq_disable();
 117 }
 118
 119 /* default implementation */
 120 void __attribute__ ((weak)) arch_suspend_enable_irqs(void)
 121 {
 122         local_irq_enable();
 123 }
 124
 125 /**
 126  *      suspend_enter - enter the desired system sleep state.
 127  *      @state:         state to enter
 128  *
 129  *      This function should be called after devices have been suspended.
 130  */
 131 int suspend_enter(suspend_state_t state)
 132 {
 133         int error = 0;
 134
 135         arch_suspend_disable_irqs();
 136         BUG_ON(!irqs_disabled());
 137
 138         if ((error = device_power_down(PMSG_SUSPEND))) {
 139                 printk(KERN_ERR "Some devices failed to power down\n");
 140                 goto Done;
 141         }
 142         error = pm_ops->enter(state);
 143         device_power_up();
 144  Done:
 145         arch_suspend_enable_irqs();
 146         BUG_ON(irqs_disabled());
 147         return error;
 148 }
 149
 150 /**
 151  *      suspend_devices_and_enter - suspend devices and enter the desired system sleep
 152  *                        state.
 153  *      @state:           state to enter
 154  */
 155 int suspend_devices_and_enter(suspend_state_t state)
 156 {
 157         int error;
 158
 159         if (!pm_ops)
 160                 return -ENOSYS;
 161
 162         if (pm_ops->set_target) {
 163                 error = pm_ops->set_target(state);
 164                 if (error)
 165                         return error;
 166         }
 167         suspend_console();
 168         error = device_suspend(PMSG_SUSPEND);
 169         if (error) {
 170                 printk(KERN_ERR "Some devices failed to suspend\n");
 171                 goto Resume_console;
 172         }
 173         if (pm_ops->prepare) {
 174                 error = pm_ops->prepare(state);
 175                 if (error)
 176                         goto Resume_devices;
 177         }
 178         error = disable_nonboot_cpus();
 179         if (!error)
 180                 suspend_enter(state);
 181
 182         enable_nonboot_cpus();
 183         pm_finish(state);
 184  Resume_devices:
 185         device_resume();
 186  Resume_console:
 187         resume_console();
 188         return error;
 189 }
 190
 191 /**
 192  *      suspend_finish - Do final work before exiting suspend sequence.
 193  *
 194  *      Call platform code to clean up, restart processes, and free the
 195  *      console that we've allocated. This is not called for suspend-to-disk.
 196  */
 197 static void suspend_finish(void)
 198 {
 199         thaw_processes();
 200         pm_restore_console();
 201         pm_notifier_call_chain(PM_POST_SUSPEND);
 202 }
 203
 204
 205
 206
 207 static const char * const pm_states[PM_SUSPEND_MAX] = {
 208         [PM_SUSPEND_STANDBY]    = "standby",
 209         [PM_SUSPEND_MEM]        = "mem",
 210 };
 211
 212 static inline int valid_state(suspend_state_t state)
 213 {
 214         /* All states need lowlevel support and need to be valid
 215          * to the lowlevel implementation, no valid callback
 216          * implies that none are valid. */
 217         if (!pm_ops || !pm_ops->valid || !pm_ops->valid(state))
 218                 return 0;
 219         return 1;
 220 }
 221
 222
 223 /**
 224  *      enter_state - Do common work of entering low-power state.
 225  *      @state:         pm_state structure for state we're entering.
 226  *
 227  *      Make sure we're the only ones trying to enter a sleep state. Fail
 228  *      if someone has beat us to it, since we don't want anything weird to
 229  *      happen when we wake up.
 230  *      Then, do the setup for suspend, enter the state, and cleaup (after
 231  *      we've woken up).
 232  */
 233 static int enter_state(suspend_state_t state)
 234 {
 235         int error;
 236
 237         if (!valid_state(state))
 238                 return -ENODEV;
 239         if (!mutex_trylock(&pm_mutex))
 240                 return -EBUSY;
 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);