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   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 /*This is just an arbitrary number */
  27 #define FREE_PAGE_NUMBER (100)
  28
  29 DEFINE_MUTEX(pm_mutex);
  30
  31 struct pm_ops *pm_ops;
  32
  33 /**
  34  *      pm_set_ops - Set the global power method table.
  35  *      @ops:   Pointer to ops structure.
  36  */
  37
  38 void pm_set_ops(struct pm_ops * ops)
  39 {
  40         mutex_lock(&pm_mutex);
  41         pm_ops = ops;
  42         mutex_unlock(&pm_mutex);
  43 }
  44
  45 /**
  46  * pm_valid_only_mem - generic memory-only valid callback
  47  *
  48  * pm_ops drivers that implement mem suspend only and only need
  49  * to check for that in their .valid callback can use this instead
  50  * of rolling their own .valid callback.
  51  */
  52 int pm_valid_only_mem(suspend_state_t state)
  53 {
  54         return state == PM_SUSPEND_MEM;
  55 }
  56
  57
  58 static inline void pm_finish(suspend_state_t state)
  59 {
  60         if (pm_ops->finish)
  61                 pm_ops->finish(state);
  62 }
  63
  64 /**
  65  *      suspend_prepare - Do prep work before entering low-power state.
  66  *      @state:         State we're entering.
  67  *
  68  *      This is common code that is called for each state that we're
  69  *      entering. Allocate a console, stop all processes, then make sure
  70  *      the platform can enter the requested state.
  71  */
  72
  73 static int suspend_prepare(suspend_state_t state)
  74 {
  75         int error;
  76         unsigned int free_pages;
  77
  78         if (!pm_ops || !pm_ops->enter)
  79                 return -EPERM;
  80
  81         pm_prepare_console();
  82
  83         if (freeze_processes()) {
  84                 error = -EAGAIN;
  85                 goto Thaw;
  86         }
  87
  88         if ((free_pages = global_page_state(NR_FREE_PAGES))
  89                         < FREE_PAGE_NUMBER) {
  90                 pr_debug("PM: free some memory\n");
  91                 shrink_all_memory(FREE_PAGE_NUMBER - free_pages);
  92                 if (nr_free_pages() < FREE_PAGE_NUMBER) {
  93                         error = -ENOMEM;
  94                         printk(KERN_ERR "PM: No enough memory\n");
  95                         goto Thaw;
  96                 }
  97         }
  98
  99         if (pm_ops->set_target) {
 100                 error = pm_ops->set_target(state);
 101                 if (error)
 102                         goto Thaw;
 103         }
 104         suspend_console();
 105         error = device_suspend(PMSG_SUSPEND);
 106         if (error) {
 107                 printk(KERN_ERR "Some devices failed to suspend\n");
 108                 goto Resume_console;
 109         }
 110         if (pm_ops->prepare) {
 111                 if ((error = pm_ops->prepare(state)))
 112                         goto Resume_devices;
 113         }
 114
 115         error = disable_nonboot_cpus();
 116         if (!error)
 117                 return 0;
 118
 119         enable_nonboot_cpus();
 120         pm_finish(state);
 121  Resume_devices:
 122         device_resume();
 123  Resume_console:
 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 };
 188
 189 static inline int valid_state(suspend_state_t state)
 190 {
 191         /* All states need lowlevel support and need to be valid
 192          * to the lowlevel implementation, no valid callback
 193          * implies that none are valid. */
 194         if (!pm_ops || !pm_ops->valid || !pm_ops->valid(state))
 195                 return 0;
 196         return 1;
 197 }
 198
 199
 200 /**
 201  *      enter_state - Do common work of entering low-power state.
 202  *      @state:         pm_state structure for state we're entering.
 203  *
 204  *      Make sure we're the only ones trying to enter a sleep state. Fail
 205  *      if someone has beat us to it, since we don't want anything weird to
 206  *      happen when we wake up.
 207  *      Then, do the setup for suspend, enter the state, and cleaup (after
 208  *      we've woken up).
 209  */
 210
 211 static int enter_state(suspend_state_t state)
 212 {
 213         int error;
 214
 215         if (!valid_state(state))
 216                 return -ENODEV;
 217         if (!mutex_trylock(&pm_mutex))
 218                 return -EBUSY;
 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 /**
 236  *      pm_suspend - Externally visible function for suspending system.
 237  *      @state:         Enumerated value of state to enter.
 238  *
 239  *      Determine whether or not value is within range, get state
 240  *      structure, and enter (above).
 241  */
 242
 243 int pm_suspend(suspend_state_t state)
 244 {
 245         if (state > PM_SUSPEND_ON && state <= PM_SUSPEND_MAX)
 246                 return enter_state(state);
 247         return -EINVAL;
 248 }
 249
 250 EXPORT_SYMBOL(pm_suspend);
 251
 252 decl_subsys(power,NULL,NULL);
 253
 254
 255 /**
 256  *      state - control system power state.
 257  *
 258  *      show() returns what states are supported, which is hard-coded to
 259  *      'standby' (Power-On Suspend), 'mem' (Suspend-to-RAM), and
 260  *      'disk' (Suspend-to-Disk).
 261  *
 262  *      store() accepts one of those strings, translates it into the
 263  *      proper enumerated value, and initiates a suspend transition.
 264  */
 265
 266 static ssize_t state_show(struct kset *kset, char *buf)
 267 {
 268         int i;
 269         char * s = buf;
 270
 271         for (i = 0; i < PM_SUSPEND_MAX; i++) {
 272                 if (pm_states[i] && valid_state(i))
 273                         s += sprintf(s,"%s ", pm_states[i]);
 274         }
 275 #ifdef CONFIG_SOFTWARE_SUSPEND
 276         s += sprintf(s, "%s\n", "disk");
 277 #else
 278         if (s != buf)
 279                 /* convert the last space to a newline */
 280                 *(s-1) = '\n';
 281 #endif
 282         return (s - buf);
 283 }
 284
 285 static ssize_t state_store(struct kset *kset, const char *buf, size_t n)
 286 {
 287         suspend_state_t state = PM_SUSPEND_STANDBY;
 288         const char * const *s;
 289         char *p;
 290         int error;
 291         int len;
 292
 293         p = memchr(buf, '\n', n);
 294         len = p ? p - buf : n;
 295
 296         /* First, check if we are requested to hibernate */
 297         if (len == 4 && !strncmp(buf, "disk", len)) {
 298                 error = hibernate();
 299                 return error ? error : n;
 300         }
 301
 302         for (s = &pm_states[state]; state < PM_SUSPEND_MAX; s++, state++) {
 303                 if (*s && len == strlen(*s) && !strncmp(buf, *s, len))
 304                         break;
 305         }
 306         if (state < PM_SUSPEND_MAX && *s)
 307                 error = enter_state(state);
 308         else
 309                 error = -EINVAL;
 310         return error ? error : n;
 311 }
 312
 313 power_attr(state);
 314
 315 #ifdef CONFIG_PM_TRACE
 316 int pm_trace_enabled;
 317
 318 static ssize_t pm_trace_show(struct kset *kset, char *buf)
 319 {
 320         return sprintf(buf, "%d\n", pm_trace_enabled);
 321 }
 322
 323 static ssize_t
 324 pm_trace_store(struct kset *kset, const char *buf, size_t n)
 325 {
 326         int val;
 327
 328         if (sscanf(buf, "%d", &val) == 1) {
 329                 pm_trace_enabled = !!val;
 330                 return n;
 331         }
 332         return -EINVAL;
 333 }
 334
 335 power_attr(pm_trace);
 336
 337 static struct attribute * g[] = {
 338         &state_attr.attr,
 339         &pm_trace_attr.attr,
 340         NULL,
 341 };
 342 #else
 343 static struct attribute * g[] = {
 344         &state_attr.attr,
 345         NULL,
 346 };
 347 #endif /* CONFIG_PM_TRACE */
 348
 349 static struct attribute_group attr_group = {
 350         .attrs = g,
 351 };
 352
 353
 354 static int __init pm_init(void)
 355 {
 356         int error = subsystem_register(&power_subsys);
 357         if (!error)
 358                 error = sysfs_create_group(&power_subsys.kobj,&attr_group);
 359         return error;
 360 }
 361
 362 core_initcall(pm_init);