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/kobject.h>
  12 #include <linux/string.h>
  13 #include <linux/resume-trace.h>
  14 #include <linux/workqueue.h>
  15
  16 #include "power.h"
  17
  18 DEFINE_MUTEX(pm_mutex);
  19
  20 unsigned int pm_flags;
  21 EXPORT_SYMBOL(pm_flags);
  22
  23 #ifdef CONFIG_PM_SLEEP
  24
  25 /* Routines for PM-transition notifications */
  26
  27 static BLOCKING_NOTIFIER_HEAD(pm_chain_head);
  28
  29 int register_pm_notifier(struct notifier_block *nb)
  30 {
  31         return blocking_notifier_chain_register(&pm_chain_head, nb);
  32 }
  33 EXPORT_SYMBOL_GPL(register_pm_notifier);
  34
  35 int unregister_pm_notifier(struct notifier_block *nb)
  36 {
  37         return blocking_notifier_chain_unregister(&pm_chain_head, nb);
  38 }
  39 EXPORT_SYMBOL_GPL(unregister_pm_notifier);
  40
  41 int pm_notifier_call_chain(unsigned long val)
  42 {
  43         return (blocking_notifier_call_chain(&pm_chain_head, val, NULL)
  44                         == NOTIFY_BAD) ? -EINVAL : 0;
  45 }
  46
  47 #ifdef CONFIG_PM_DEBUG
  48 int pm_test_level = TEST_NONE;
  49
  50 static const char * const pm_tests[__TEST_AFTER_LAST] = {
  51         [TEST_NONE] = "none",
  52         [TEST_CORE] = "core",
  53         [TEST_CPUS] = "processors",
  54         [TEST_PLATFORM] = "platform",
  55         [TEST_DEVICES] = "devices",
  56         [TEST_FREEZER] = "freezer",
  57 };
  58
  59 static ssize_t pm_test_show(struct kobject *kobj, struct kobj_attribute *attr,
  60                                 char *buf)
  61 {
  62         char *s = buf;
  63         int level;
  64
  65         for (level = TEST_FIRST; level <= TEST_MAX; level++)
  66                 if (pm_tests[level]) {
  67                         if (level == pm_test_level)
  68                                 s += sprintf(s, "[%s] ", pm_tests[level]);
  69                         else
  70                                 s += sprintf(s, "%s ", pm_tests[level]);
  71                 }
  72
  73         if (s != buf)
  74                 /* convert the last space to a newline */
  75                 *(s-1) = '\n';
  76
  77         return (s - buf);
  78 }
  79
  80 static ssize_t pm_test_store(struct kobject *kobj, struct kobj_attribute *attr,
  81                                 const char *buf, size_t n)
  82 {
  83         const char * const *s;
  84         int level;
  85         char *p;
  86         int len;
  87         int error = -EINVAL;
  88
  89         p = memchr(buf, '\n', n);
  90         len = p ? p - buf : n;
  91
  92         mutex_lock(&pm_mutex);
  93
  94         level = TEST_FIRST;
  95         for (s = &pm_tests[level]; level <= TEST_MAX; s++, level++)
  96                 if (*s && len == strlen(*s) && !strncmp(buf, *s, len)) {
  97                         pm_test_level = level;
  98                         error = 0;
  99                         break;
 100                 }
 101
 102         mutex_unlock(&pm_mutex);
 103
 104         return error ? error : n;
 105 }
 106
 107 power_attr(pm_test);
 108 #endif /* CONFIG_PM_DEBUG */
 109
 110 #endif /* CONFIG_PM_SLEEP */
 111
 112 struct kobject *power_kobj;
 113
 114 /**
 115  *      state - control system power state.
 116  *
 117  *      show() returns what states are supported, which is hard-coded to
 118  *      'standby' (Power-On Suspend), 'mem' (Suspend-to-RAM), and
 119  *      'disk' (Suspend-to-Disk).
 120  *
 121  *      store() accepts one of those strings, translates it into the
 122  *      proper enumerated value, and initiates a suspend transition.
 123  */
 124 static ssize_t state_show(struct kobject *kobj, struct kobj_attribute *attr,
 125                           char *buf)
 126 {
 127         char *s = buf;
 128 #ifdef CONFIG_SUSPEND
 129         int i;
 130
 131         for (i = 0; i < PM_SUSPEND_MAX; i++) {
 132                 if (pm_states[i] && valid_state(i))
 133                         s += sprintf(s,"%s ", pm_states[i]);
 134         }
 135 #endif
 136 #ifdef CONFIG_HIBERNATION
 137         s += sprintf(s, "%s\n", "disk");
 138 #else
 139         if (s != buf)
 140                 /* convert the last space to a newline */
 141                 *(s-1) = '\n';
 142 #endif
 143         return (s - buf);
 144 }
 145
 146 static ssize_t state_store(struct kobject *kobj, struct kobj_attribute *attr,
 147                            const char *buf, size_t n)
 148 {
 149 #ifdef CONFIG_SUSPEND
 150         suspend_state_t state = PM_SUSPEND_STANDBY;
 151         const char * const *s;
 152 #endif
 153         char *p;
 154         int len;
 155         int error = -EINVAL;
 156
 157         p = memchr(buf, '\n', n);
 158         len = p ? p - buf : n;
 159
 160         /* First, check if we are requested to hibernate */
 161         if (len == 4 && !strncmp(buf, "disk", len)) {
 162                 error = hibernate();
 163   goto Exit;
 164         }
 165
 166 #ifdef CONFIG_SUSPEND
 167         for (s = &pm_states[state]; state < PM_SUSPEND_MAX; s++, state++) {
 168                 if (*s && len == strlen(*s) && !strncmp(buf, *s, len))
 169                         break;
 170         }
 171         if (state < PM_SUSPEND_MAX && *s)
 172                 error = enter_state(state);
 173 #endif
 174
 175  Exit:
 176         return error ? error : n;
 177 }
 178
 179 power_attr(state);
 180
 181 #ifdef CONFIG_PM_TRACE
 182 int pm_trace_enabled;
 183
 184 static ssize_t pm_trace_show(struct kobject *kobj, struct kobj_attribute *attr,
 185                              char *buf)
 186 {
 187         return sprintf(buf, "%d\n", pm_trace_enabled);
 188 }
 189
 190 static ssize_t
 191 pm_trace_store(struct kobject *kobj, struct kobj_attribute *attr,
 192                const char *buf, size_t n)
 193 {
 194         int val;
 195
 196         if (sscanf(buf, "%d", &val) == 1) {
 197                 pm_trace_enabled = !!val;
 198                 return n;
 199         }
 200         return -EINVAL;
 201 }
 202
 203 power_attr(pm_trace);
 204 #endif /* CONFIG_PM_TRACE */
 205
 206 static struct attribute * g[] = {
 207         &state_attr.attr,
 208 #ifdef CONFIG_PM_TRACE
 209         &pm_trace_attr.attr,
 210 #endif
 211 #if defined(CONFIG_PM_SLEEP) && defined(CONFIG_PM_DEBUG)
 212         &pm_test_attr.attr,
 213 #endif
 214         NULL,
 215 };
 216
 217 static struct attribute_group attr_group = {
 218         .attrs = g,
 219 };
 220
 221 #ifdef CONFIG_PM_RUNTIME
 222 struct workqueue_struct *pm_wq;
 223
 224 static int __init pm_start_workqueue(void)
 225 {
 226         pm_wq = create_freezeable_workqueue("pm");
 227
 228         return pm_wq ? 0 : -ENOMEM;
 229 }
 230 #else
 231 static inline int pm_start_workqueue(void) { return 0; }
 232 #endif
 233
 234 static int __init pm_init(void)
 235 {
 236         int error = pm_start_workqueue();
 237         if (error)
 238                 return error;
 239         power_kobj = kobject_create_and_add("power", NULL);
 240         if (!power_kobj)
 241                 return -ENOMEM;
 242         return sysfs_create_group(power_kobj, &attr_group);
 243 }
 244
 245 core_initcall(pm_init);