err.no Git - linux-2.6/blob - 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 static inline void pm_finish(suspend_state_t state)
  52 {
  53         if (pm_ops->finish)
  54                 pm_ops->finish(state);
  55 }
  56
  57 /**
  58  *      suspend_prepare - Do prep work before entering low-power state.
  59  *      @state:         State we're entering.
  60  *
  61  *      This is common code that is called for each state that we're
  62  *      entering. Allocate a console, stop all processes, then make sure
  63  *      the platform can enter the requested state.
  64  */
  65
  66 static int suspend_prepare(suspend_state_t state)
  67 {
  68         int error;
  69         unsigned int free_pages;
  70
  71         if (!pm_ops || !pm_ops->enter)
  72                 return -EPERM;
  73
  74         pm_prepare_console();
  75
  76         if (freeze_processes()) {
  77                 error = -EAGAIN;
  78                 goto Thaw;
  79         }
  80
  81         if ((free_pages = global_page_state(NR_FREE_PAGES))
  82                         < FREE_PAGE_NUMBER) {
  83                 pr_debug("PM: free some memory\n");
  84                 shrink_all_memory(FREE_PAGE_NUMBER - free_pages);
  85                 if (nr_free_pages() < FREE_PAGE_NUMBER) {
  86                         error = -ENOMEM;
  87                         printk(KERN_ERR "PM: No enough memory\n");
  88                         goto Thaw;
  89                 }
  90         }
  91
  92         if (pm_ops->prepare) {
  93                 if ((error = pm_ops->prepare(state)))
  94                         goto Thaw;
  95         }
  96
  97         suspend_console();
  98         error = device_suspend(PMSG_SUSPEND);
  99         if (error) {
 100                 printk(KERN_ERR "Some devices failed to suspend\n");
 101                 goto Resume_devices;
 102         }
 103         error = disable_nonboot_cpus();
 104         if (!error)
 105                 return 0;
 106
 107         enable_nonboot_cpus();
 108  Resume_devices:
 109         pm_finish(state);
 110         device_resume();
 111         resume_console();
 112  Thaw:
 113         thaw_processes();
 114         pm_restore_console();
 115         return error;
 116 }
 117
 118 /* default implementation */
 119 void __attribute__ ((weak)) arch_suspend_disable_irqs(void)
 120 {
 121         local_irq_disable();
 122 }
 123
 124 /* default implementation */
 125 void __attribute__ ((weak)) arch_suspend_enable_irqs(void)
 126 {
 127         local_irq_enable();
 128 }
 129
 130 int suspend_enter(suspend_state_t state)
 131 {
 132         int error = 0;
 133
 134         arch_suspend_disable_irqs();
 135         BUG_ON(!irqs_disabled());
 136
 137         if ((error = device_power_down(PMSG_SUSPEND))) {
 138                 printk(KERN_ERR "Some devices failed to power down\n");
 139                 goto Done;
 140         }
 141         error = pm_ops->enter(state);
 142         device_power_up();
 143  Done:
 144         arch_suspend_enable_irqs();
 145         BUG_ON(irqs_disabled());
 146         return error;
 147 }
 148
 149
 150 /**
 151  *      suspend_finish - Do final work before exiting suspend sequence.
 152  *      @state:         State we're coming out of.
 153  *
 154  *      Call platform code to clean up, restart processes, and free the
 155  *      console that we've allocated. This is not called for suspend-to-disk.
 156  */
 157
 158 static void suspend_finish(suspend_state_t state)
 159 {
 160         enable_nonboot_cpus();
 161         pm_finish(state);
 162         device_resume();
 163         resume_console();
 164         thaw_processes();
 165         pm_restore_console();
 166 }
 167
 168
 169
 170
 171 static const char * const pm_states[PM_SUSPEND_MAX] = {
 172         [PM_SUSPEND_STANDBY]    = "standby",
 173         [PM_SUSPEND_MEM]        = "mem",
 174 #ifdef CONFIG_SOFTWARE_SUSPEND
 175         [PM_SUSPEND_DISK]       = "disk",
 176 #endif
 177 };
 178
 179 static inline int valid_state(suspend_state_t state)
 180 {
 181         /* Suspend-to-disk does not really need low-level support.
 182          * It can work with reboot if needed. */
 183         if (state == PM_SUSPEND_DISK)
 184                 return 1;
 185
 186         /* all other states need lowlevel support and need to be
 187          * valid to the lowlevel implementation, no valid callback
 188          * implies that all are valid. */
 189         if (!pm_ops || (pm_ops->valid && !pm_ops->valid(state)))
 190                 return 0;
 191         return 1;
 192 }
 193
 194
 195 /**
 196  *      enter_state - Do common work of entering low-power state.
 197  *      @state:         pm_state structure for state we're entering.
 198  *
 199  *      Make sure we're the only ones trying to enter a sleep state. Fail
 200  *      if someone has beat us to it, since we don't want anything weird to
 201  *      happen when we wake up.
 202  *      Then, do the setup for suspend, enter the state, and cleaup (after
 203  *      we've woken up).
 204  */
 205
 206 static int enter_state(suspend_state_t state)
 207 {
 208         int error;
 209
 210         if (!valid_state(state))
 211                 return -ENODEV;
 212         if (!mutex_trylock(&pm_mutex))
 213                 return -EBUSY;
 214
 215         if (state == PM_SUSPEND_DISK) {
 216                 error = pm_suspend_disk();
 217                 goto Unlock;
 218         }
 219
 220         pr_debug("PM: Preparing system for %s sleep\n", pm_states[state]);
 221         if ((error = suspend_prepare(state)))
 222                 goto Unlock;
 223
 224         pr_debug("PM: Entering %s sleep\n", pm_states[state]);
 225         error = suspend_enter(state);
 226
 227         pr_debug("PM: Finishing wakeup.\n");
 228         suspend_finish(state);
 229  Unlock:
 230         mutex_unlock(&pm_mutex);
 231         return error;
 232 }
 233
 234 /*
 235  * This is main interface to the outside world. It needs to be
 236  * called from process context.
 237  */
 238 int software_suspend(void)
 239 {
 240         return enter_state(PM_SUSPEND_DISK);
 241 }
 242
 243
 244 /**
 245  *      pm_suspend - Externally visible function for suspending system.
 246  *      @state:         Enumarted value of state to enter.
 247  *
 248  *      Determine whether or not value is within range, get state
 249  *      structure, and enter (above).
 250  */
 251
 252 int pm_suspend(suspend_state_t state)
 253 {
 254         if (state > PM_SUSPEND_ON && state <= PM_SUSPEND_MAX)
 255                 return enter_state(state);
 256         return -EINVAL;
 257 }
 258
 259 EXPORT_SYMBOL(pm_suspend);
 260
 261 decl_subsys(power,NULL,NULL);
 262
 263
 264 /**
 265  *      state - control system power state.
 266  *
 267  *      show() returns what states are supported, which is hard-coded to
 268  *      'standby' (Power-On Suspend), 'mem' (Suspend-to-RAM), and
 269  *      'disk' (Suspend-to-Disk).
 270  *
 271  *      store() accepts one of those strings, translates it into the
 272  *      proper enumerated value, and initiates a suspend transition.
 273  */
 274
 275 static ssize_t state_show(struct subsystem * subsys, char * buf)
 276 {
 277         int i;
 278         char * s = buf;
 279
 280         for (i = 0; i < PM_SUSPEND_MAX; i++) {
 281                 if (pm_states[i] && valid_state(i))
 282                         s += sprintf(s,"%s ", pm_states[i]);
 283         }
 284         s += sprintf(s,"\n");
 285         return (s - buf);
 286 }
 287
 288 static ssize_t state_store(struct subsystem * subsys, const char * buf, size_t n)
 289 {
 290         suspend_state_t state = PM_SUSPEND_STANDBY;
 291         const char * const *s;
 292         char *p;
 293         int error;
 294         int len;
 295
 296         p = memchr(buf, '\n', n);
 297         len = p ? p - buf : n;
 298
 299         for (s = &pm_states[state]; state < PM_SUSPEND_MAX; s++, state++) {
 300                 if (*s && !strncmp(buf, *s, len))
 301                         break;
 302         }
 303         if (state < PM_SUSPEND_MAX && *s)
 304                 error = enter_state(state);
 305         else
 306                 error = -EINVAL;
 307         return error ? error : n;
 308 }
 309
 310 power_attr(state);
 311
 312 #ifdef CONFIG_PM_TRACE
 313 int pm_trace_enabled;
 314
 315 static ssize_t pm_trace_show(struct subsystem * subsys, char * buf)
 316 {
 317         return sprintf(buf, "%d\n", pm_trace_enabled);
 318 }
 319
 320 static ssize_t
 321 pm_trace_store(struct subsystem * subsys, const char * buf, size_t n)
 322 {
 323         int val;
 324
 325         if (sscanf(buf, "%d", &val) == 1) {
 326                 pm_trace_enabled = !!val;
 327                 return n;
 328         }
 329         return -EINVAL;
 330 }
 331
 332 power_attr(pm_trace);
 333
 334 static struct attribute * g[] = {
 335         &state_attr.attr,
 336         &pm_trace_attr.attr,
 337         NULL,
 338 };
 339 #else
 340 static struct attribute * g[] = {
 341         &state_attr.attr,
 342         NULL,
 343 };
 344 #endif /* CONFIG_PM_TRACE */
 345
 346 static struct attribute_group attr_group = {
 347         .attrs = g,
 348 };
 349
 350
 351 static int __init pm_init(void)
 352 {
 353         int error = subsystem_register(&power_subsys);
 354         if (!error)
 355                 error = sysfs_create_group(&power_subsys.kset.kobj,&attr_group);
 356         return error;
 357 }
 358
 359 core_initcall(pm_init);