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/pm.h>
  19 #include <linux/console.h>
  20 #include <linux/cpu.h>
  21 #include <linux/resume-trace.h>
  22 #include <linux/freezer.h>
  23 #include <linux/vmstat.h>
  24
  25 #include "power.h"
  26
  27 /*This is just an arbitrary number */
  28 #define FREE_PAGE_NUMBER (100)
  29
  30 DEFINE_MUTEX(pm_mutex);
  31
  32 struct pm_ops *pm_ops;
  33 suspend_disk_method_t pm_disk_mode = PM_DISK_SHUTDOWN;
  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         if (ops && ops->pm_disk_mode != PM_DISK_INVALID) {
  45                 pm_disk_mode = ops->pm_disk_mode;
  46         } else
  47                 pm_disk_mode = PM_DISK_SHUTDOWN;
  48         mutex_unlock(&pm_mutex);
  49 }
  50
  51 /**
  52  * pm_valid_only_mem - generic memory-only valid callback
  53  *
  54  * pm_ops drivers that implement mem suspend only and only need
  55  * to check for that in their .valid callback can use this instead
  56  * of rolling their own .valid callback.
  57  */
  58 int pm_valid_only_mem(suspend_state_t state)
  59 {
  60         return state == PM_SUSPEND_MEM;
  61 }
  62
  63
  64 static inline void pm_finish(suspend_state_t state)
  65 {
  66         if (pm_ops->finish)
  67                 pm_ops->finish(state);
  68 }
  69
  70 /**
  71  *      suspend_prepare - Do prep work before entering low-power state.
  72  *      @state:         State we're entering.
  73  *
  74  *      This is common code that is called for each state that we're
  75  *      entering. Allocate a console, stop all processes, then make sure
  76  *      the platform can enter the requested state.
  77  */
  78
  79 static int suspend_prepare(suspend_state_t state)
  80 {
  81         int error;
  82         unsigned int free_pages;
  83
  84         if (!pm_ops || !pm_ops->enter)
  85                 return -EPERM;
  86
  87         pm_prepare_console();
  88
  89         if (freeze_processes()) {
  90                 error = -EAGAIN;
  91                 goto Thaw;
  92         }
  93
  94         if ((free_pages = global_page_state(NR_FREE_PAGES))
  95                         < FREE_PAGE_NUMBER) {
  96                 pr_debug("PM: free some memory\n");
  97                 shrink_all_memory(FREE_PAGE_NUMBER - free_pages);
  98                 if (nr_free_pages() < FREE_PAGE_NUMBER) {
  99                         error = -ENOMEM;
 100                         printk(KERN_ERR "PM: No enough memory\n");
 101                         goto Thaw;
 102                 }
 103         }
 104
 105         if (pm_ops->prepare) {
 106                 if ((error = pm_ops->prepare(state)))
 107                         goto Thaw;
 108         }
 109
 110         suspend_console();
 111         error = device_suspend(PMSG_SUSPEND);
 112         if (error) {
 113                 printk(KERN_ERR "Some devices failed to suspend\n");
 114                 goto Resume_devices;
 115         }
 116         error = disable_nonboot_cpus();
 117         if (!error)
 118                 return 0;
 119
 120         enable_nonboot_cpus();
 121  Resume_devices:
 122         pm_finish(state);
 123         device_resume();
 124         resume_console();
 125  Thaw:
 126         thaw_processes();
 127         pm_restore_console();
 128         return error;
 129 }
 130
 131 /* default implementation */
 132 void __attribute__ ((weak)) arch_suspend_disable_irqs(void)
 133 {
 134         local_irq_disable();
 135 }
 136
 137 /* default implementation */
 138 void __attribute__ ((weak)) arch_suspend_enable_irqs(void)
 139 {
 140         local_irq_enable();
 141 }
 142
 143 int suspend_enter(suspend_state_t state)
 144 {
 145         int error = 0;
 146
 147         arch_suspend_disable_irqs();
 148         BUG_ON(!irqs_disabled());
 149
 150         if ((error = device_power_down(PMSG_SUSPEND))) {
 151                 printk(KERN_ERR "Some devices failed to power down\n");
 152                 goto Done;
 153         }
 154         error = pm_ops->enter(state);
 155         device_power_up();
 156  Done:
 157         arch_suspend_enable_irqs();
 158         BUG_ON(irqs_disabled());
 159         return error;
 160 }
 161
 162
 163 /**
 164  *      suspend_finish - Do final work before exiting suspend sequence.
 165  *      @state:         State we're coming out of.
 166  *
 167  *      Call platform code to clean up, restart processes, and free the
 168  *      console that we've allocated. This is not called for suspend-to-disk.
 169  */
 170
 171 static void suspend_finish(suspend_state_t state)
 172 {
 173         enable_nonboot_cpus();
 174         pm_finish(state);
 175         device_resume();
 176         resume_console();
 177         thaw_processes();
 178         pm_restore_console();
 179 }
 180
 181
 182
 183
 184 static const char * const pm_states[PM_SUSPEND_MAX] = {
 185         [PM_SUSPEND_STANDBY]    = "standby",
 186         [PM_SUSPEND_MEM]        = "mem",
 187         [PM_SUSPEND_DISK]       = "disk",
 188 };
 189
 190 static inline int valid_state(suspend_state_t state)
 191 {
 192         /* Suspend-to-disk does not really need low-level support.
 193          * It can work with shutdown/reboot if needed. If it isn't
 194          * configured, then it cannot be supported.
 195          */
 196         if (state == PM_SUSPEND_DISK)
 197 #ifdef CONFIG_SOFTWARE_SUSPEND
 198                 return 1;
 199 #else
 200                 return 0;
 201 #endif
 202
 203         /* all other states need lowlevel support and need to be
 204          * valid to the lowlevel implementation, no valid callback
 205          * implies that none are valid. */
 206         if (!pm_ops || !pm_ops->valid || !pm_ops->valid(state))
 207                 return 0;
 208         return 1;
 209 }
 210
 211
 212 /**
 213  *      enter_state - Do common work of entering low-power state.
 214  *      @state:         pm_state structure for state we're entering.
 215  *
 216  *      Make sure we're the only ones trying to enter a sleep state. Fail
 217  *      if someone has beat us to it, since we don't want anything weird to
 218  *      happen when we wake up.
 219  *      Then, do the setup for suspend, enter the state, and cleaup (after
 220  *      we've woken up).
 221  */
 222
 223 static int enter_state(suspend_state_t state)
 224 {
 225         int error;
 226
 227         if (!valid_state(state))
 228                 return -ENODEV;
 229         if (!mutex_trylock(&pm_mutex))
 230                 return -EBUSY;
 231
 232         if (state == PM_SUSPEND_DISK) {
 233                 error = pm_suspend_disk();
 234                 goto Unlock;
 235         }
 236
 237         pr_debug("PM: Preparing system for %s sleep\n", pm_states[state]);
 238         if ((error = suspend_prepare(state)))
 239                 goto Unlock;
 240
 241         pr_debug("PM: Entering %s sleep\n", pm_states[state]);
 242         error = suspend_enter(state);
 243
 244         pr_debug("PM: Finishing wakeup.\n");
 245         suspend_finish(state);
 246  Unlock:
 247         mutex_unlock(&pm_mutex);
 248         return error;
 249 }
 250
 251
 252 /**
 253  *      pm_suspend - Externally visible function for suspending system.
 254  *      @state:         Enumarted value of state to enter.
 255  *
 256  *      Determine whether or not value is within range, get state
 257  *      structure, and enter (above).
 258  */
 259
 260 int pm_suspend(suspend_state_t state)
 261 {
 262         if (state > PM_SUSPEND_ON && state <= PM_SUSPEND_MAX)
 263                 return enter_state(state);
 264         return -EINVAL;
 265 }
 266
 267 EXPORT_SYMBOL(pm_suspend);
 268
 269 decl_subsys(power,NULL,NULL);
 270
 271
 272 /**
 273  *      state - control system power state.
 274  *
 275  *      show() returns what states are supported, which is hard-coded to
 276  *      'standby' (Power-On Suspend), 'mem' (Suspend-to-RAM), and
 277  *      'disk' (Suspend-to-Disk).
 278  *
 279  *      store() accepts one of those strings, translates it into the
 280  *      proper enumerated value, and initiates a suspend transition.
 281  */
 282
 283 static ssize_t state_show(struct kset *kset, char *buf)
 284 {
 285         int i;
 286         char * s = buf;
 287
 288         for (i = 0; i < PM_SUSPEND_MAX; i++) {
 289                 if (pm_states[i] && valid_state(i))
 290                         s += sprintf(s,"%s ", pm_states[i]);
 291         }
 292         s += sprintf(s,"\n");
 293         return (s - buf);
 294 }
 295
 296 static ssize_t state_store(struct kset *kset, const char *buf, size_t n)
 297 {
 298         suspend_state_t state = PM_SUSPEND_STANDBY;
 299         const char * const *s;
 300         char *p;
 301         int error;
 302         int len;
 303
 304         p = memchr(buf, '\n', n);
 305         len = p ? p - buf : n;
 306
 307         for (s = &pm_states[state]; state < PM_SUSPEND_MAX; s++, state++) {
 308                 if (*s && !strncmp(buf, *s, len))
 309                         break;
 310         }
 311         if (state < PM_SUSPEND_MAX && *s)
 312                 error = enter_state(state);
 313         else
 314                 error = -EINVAL;
 315         return error ? error : n;
 316 }
 317
 318 power_attr(state);
 319
 320 #ifdef CONFIG_PM_TRACE
 321 int pm_trace_enabled;
 322
 323 static ssize_t pm_trace_show(struct kset *kset, char *buf)
 324 {
 325         return sprintf(buf, "%d\n", pm_trace_enabled);
 326 }
 327
 328 static ssize_t
 329 pm_trace_store(struct kset *kset, const char *buf, size_t n)
 330 {
 331         int val;
 332
 333         if (sscanf(buf, "%d", &val) == 1) {
 334                 pm_trace_enabled = !!val;
 335                 return n;
 336         }
 337         return -EINVAL;
 338 }
 339
 340 power_attr(pm_trace);
 341
 342 static struct attribute * g[] = {
 343         &state_attr.attr,
 344         &pm_trace_attr.attr,
 345         NULL,
 346 };
 347 #else
 348 static struct attribute * g[] = {
 349         &state_attr.attr,
 350         NULL,
 351 };
 352 #endif /* CONFIG_PM_TRACE */
 353
 354 static struct attribute_group attr_group = {
 355         .attrs = g,
 356 };
 357
 358
 359 static int __init pm_init(void)
 360 {
 361         int error = subsystem_register(&power_subsys);
 362         if (!error)
 363                 error = sysfs_create_group(&power_subsys.kobj,&attr_group);
 364         return error;
 365 }
 366
 367 core_initcall(pm_init);