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