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 #ifdef CONFIG_SOFTWARE_SUSPEND
 188         [PM_SUSPEND_DISK]       = "disk",
 189 #endif
 190 };
 191
 192 static inline int valid_state(suspend_state_t state)
 193 {
 194         /* Suspend-to-disk does not really need low-level support.
 195          * It can work with reboot if needed. */
 196         if (state == PM_SUSPEND_DISK)
 197                 return 1;
 198
 199         /* all other states need lowlevel support and need to be
 200          * valid to the lowlevel implementation, no valid callback
 201          * implies that none are valid. */
 202         if (!pm_ops || !pm_ops->valid || !pm_ops->valid(state))
 203                 return 0;
 204         return 1;
 205 }
 206
 207
 208 /**
 209  *      enter_state - Do common work of entering low-power state.
 210  *      @state:         pm_state structure for state we're entering.
 211  *
 212  *      Make sure we're the only ones trying to enter a sleep state. Fail
 213  *      if someone has beat us to it, since we don't want anything weird to
 214  *      happen when we wake up.
 215  *      Then, do the setup for suspend, enter the state, and cleaup (after
 216  *      we've woken up).
 217  */
 218
 219 static int enter_state(suspend_state_t state)
 220 {
 221         int error;
 222
 223         if (!valid_state(state))
 224                 return -ENODEV;
 225         if (!mutex_trylock(&pm_mutex))
 226                 return -EBUSY;
 227
 228         if (state == PM_SUSPEND_DISK) {
 229                 error = pm_suspend_disk();
 230                 goto Unlock;
 231         }
 232
 233         pr_debug("PM: Preparing system for %s sleep\n", pm_states[state]);
 234         if ((error = suspend_prepare(state)))
 235                 goto Unlock;
 236
 237         pr_debug("PM: Entering %s sleep\n", pm_states[state]);
 238         error = suspend_enter(state);
 239
 240         pr_debug("PM: Finishing wakeup.\n");
 241         suspend_finish(state);
 242  Unlock:
 243         mutex_unlock(&pm_mutex);
 244         return error;
 245 }
 246
 247 /*
 248  * This is main interface to the outside world. It needs to be
 249  * called from process context.
 250  */
 251 int software_suspend(void)
 252 {
 253         return enter_state(PM_SUSPEND_DISK);
 254 }
 255
 256
 257 /**
 258  *      pm_suspend - Externally visible function for suspending system.
 259  *      @state:         Enumarted 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 decl_subsys(power,NULL,NULL);
 275
 276
 277 /**
 278  *      state - control system power state.
 279  *
 280  *      show() returns what states are supported, which is hard-coded to
 281  *      'standby' (Power-On Suspend), 'mem' (Suspend-to-RAM), and
 282  *      'disk' (Suspend-to-Disk).
 283  *
 284  *      store() accepts one of those strings, translates it into the
 285  *      proper enumerated value, and initiates a suspend transition.
 286  */
 287
 288 static ssize_t state_show(struct kset *kset, char *buf)
 289 {
 290         int i;
 291         char * s = buf;
 292
 293         for (i = 0; i < PM_SUSPEND_MAX; i++) {
 294                 if (pm_states[i] && valid_state(i))
 295                         s += sprintf(s,"%s ", pm_states[i]);
 296         }
 297         s += sprintf(s,"\n");
 298         return (s - buf);
 299 }
 300
 301 static ssize_t state_store(struct kset *kset, const char *buf, size_t n)
 302 {
 303         suspend_state_t state = PM_SUSPEND_STANDBY;
 304         const char * const *s;
 305         char *p;
 306         int error;
 307         int len;
 308
 309         p = memchr(buf, '\n', n);
 310         len = p ? p - buf : n;
 311
 312         for (s = &pm_states[state]; state < PM_SUSPEND_MAX; s++, state++) {
 313                 if (*s && !strncmp(buf, *s, len))
 314                         break;
 315         }
 316         if (state < PM_SUSPEND_MAX && *s)
 317                 error = enter_state(state);
 318         else
 319                 error = -EINVAL;
 320         return error ? error : n;
 321 }
 322
 323 power_attr(state);
 324
 325 #ifdef CONFIG_PM_TRACE
 326 int pm_trace_enabled;
 327
 328 static ssize_t pm_trace_show(struct kset *kset, char *buf)
 329 {
 330         return sprintf(buf, "%d\n", pm_trace_enabled);
 331 }
 332
 333 static ssize_t
 334 pm_trace_store(struct kset *kset, const char *buf, size_t n)
 335 {
 336         int val;
 337
 338         if (sscanf(buf, "%d", &val) == 1) {
 339                 pm_trace_enabled = !!val;
 340                 return n;
 341         }
 342         return -EINVAL;
 343 }
 344
 345 power_attr(pm_trace);
 346
 347 static struct attribute * g[] = {
 348         &state_attr.attr,
 349         &pm_trace_attr.attr,
 350         NULL,
 351 };
 352 #else
 353 static struct attribute * g[] = {
 354         &state_attr.attr,
 355         NULL,
 356 };
 357 #endif /* CONFIG_PM_TRACE */
 358
 359 static struct attribute_group attr_group = {
 360         .attrs = g,
 361 };
 362
 363
 364 static int __init pm_init(void)
 365 {
 366         int error = subsystem_register(&power_subsys);
 367         if (!error)
 368                 error = sysfs_create_group(&power_subsys.kobj,&attr_group);
 369         return error;
 370 }
 371
 372 core_initcall(pm_init);