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 18DEFINE_MUTEX(pm_mutex); 19 20unsigned int pm_flags; 21EXPORT_SYMBOL(pm_flags); 22 23#ifdef CONFIG_PM_SLEEP 24 25/* Routines for PM-transition notifications */ 26 27static BLOCKING_NOTIFIER_HEAD(pm_chain_head); 28 29int register_pm_notifier(struct notifier_block *nb) 30{ 31 return blocking_notifier_chain_register(&pm_chain_head, nb); 32} 33EXPORT_SYMBOL_GPL(register_pm_notifier); 34 35int unregister_pm_notifier(struct notifier_block *nb) 36{ 37 return blocking_notifier_chain_unregister(&pm_chain_head, nb); 38} 39EXPORT_SYMBOL_GPL(unregister_pm_notifier); 40 41int 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/* If set, devices may be suspended and resumed asynchronously. */ 48int pm_async_enabled = 1; 49 50static ssize_t pm_async_show(struct kobject *kobj, struct kobj_attribute *attr, 51 char *buf) 52{ 53 return sprintf(buf, "%d\n", pm_async_enabled); 54} 55 56static ssize_t pm_async_store(struct kobject *kobj, struct kobj_attribute *attr, 57 const char *buf, size_t n) 58{ 59 unsigned long val; 60 61 if (strict_strtoul(buf, 10, &val)) 62 return -EINVAL; 63 64 if (val > 1) 65 return -EINVAL; 66 67 pm_async_enabled = val; 68 return n; 69} 70 71power_attr(pm_async); 72 73#ifdef CONFIG_PM_DEBUG 74int pm_test_level = TEST_NONE; 75 76static const char * const pm_tests[__TEST_AFTER_LAST] = { 77 [TEST_NONE] = "none", 78 [TEST_CORE] = "core", 79 [TEST_CPUS] = "processors", 80 [TEST_PLATFORM] = "platform", 81 [TEST_DEVICES] = "devices", 82 [TEST_FREEZER] = "freezer", 83}; 84 85static ssize_t pm_test_show(struct kobject *kobj, struct kobj_attribute *attr, 86 char *buf) 87{ 88 char *s = buf; 89 int level; 90 91 for (level = TEST_FIRST; level <= TEST_MAX; level++) 92 if (pm_tests[level]) { 93 if (level == pm_test_level) 94 s += sprintf(s, "[%s] ", pm_tests[level]); 95 else 96 s += sprintf(s, "%s ", pm_tests[level]); 97 } 98 99 if (s != buf) 100 /* convert the last space to a newline */ 101 *(s-1) = '\n'; 102 103 return (s - buf); 104} 105 106static ssize_t pm_test_store(struct kobject *kobj, struct kobj_attribute *attr, 107 const char *buf, size_t n) 108{ 109 const char * const *s; 110 int level; 111 char *p; 112 int len; 113 int error = -EINVAL; 114 115 p = memchr(buf, '\n', n); 116 len = p ? p - buf : n; 117 118 mutex_lock(&pm_mutex); 119 120 level = TEST_FIRST; 121 for (s = &pm_tests[level]; level <= TEST_MAX; s++, level++) 122 if (*s && len == strlen(*s) && !strncmp(buf, *s, len)) { 123 pm_test_level = level; 124 error = 0; 125 break; 126 } 127 128 mutex_unlock(&pm_mutex); 129 130 return error ? error : n; 131} 132 133power_attr(pm_test); 134#endif /* CONFIG_PM_DEBUG */ 135 136#endif /* CONFIG_PM_SLEEP */ 137 138struct kobject *power_kobj; 139 140/** 141 * state - control system power state. 142 * 143 * show() returns what states are supported, which is hard-coded to 144 * 'standby' (Power-On Suspend), 'mem' (Suspend-to-RAM), and 145 * 'disk' (Suspend-to-Disk). 146 * 147 * store() accepts one of those strings, translates it into the 148 * proper enumerated value, and initiates a suspend transition. 149 */ 150static ssize_t state_show(struct kobject *kobj, struct kobj_attribute *attr, 151 char *buf) 152{ 153 char *s = buf; 154#ifdef CONFIG_SUSPEND 155 int i; 156 157 for (i = 0; i < PM_SUSPEND_MAX; i++) { 158 if (pm_states[i] && valid_state(i)) 159 s += sprintf(s,"%s ", pm_states[i]); 160 } 161#endif 162#ifdef CONFIG_HIBERNATION 163 s += sprintf(s, "%s\n", "disk"); 164#else 165 if (s != buf) 166 /* convert the last space to a newline */ 167 *(s-1) = '\n'; 168#endif 169 return (s - buf); 170} 171 172static ssize_t state_store(struct kobject *kobj, struct kobj_attribute *attr, 173 const char *buf, size_t n) 174{ 175#ifdef CONFIG_SUSPEND 176 suspend_state_t state = PM_SUSPEND_STANDBY; 177 const char * const *s; 178#endif 179 char *p; 180 int len; 181 int error = -EINVAL; 182 183 p = memchr(buf, '\n', n); 184 len = p ? p - buf : n; 185 186 /* First, check if we are requested to hibernate */ 187 if (len == 4 && !strncmp(buf, "disk", len)) { 188 error = hibernate(); 189 goto Exit; 190 } 191 192#ifdef CONFIG_SUSPEND 193 for (s = &pm_states[state]; state < PM_SUSPEND_MAX; s++, state++) { 194 if (*s && len == strlen(*s) && !strncmp(buf, *s, len)) 195 break; 196 } 197 if (state < PM_SUSPEND_MAX && *s) 198 error = enter_state(state); 199#endif 200 201 Exit: 202 return error ? error : n; 203} 204 205power_attr(state); 206 207#ifdef CONFIG_PM_SLEEP 208/* 209 * The 'wakeup_count' attribute, along with the functions defined in 210 * drivers/base/power/wakeup.c, provides a means by which wakeup events can be 211 * handled in a non-racy way. 212 * 213 * If a wakeup event occurs when the system is in a sleep state, it simply is 214 * woken up. In turn, if an event that would wake the system up from a sleep 215 * state occurs when it is undergoing a transition to that sleep state, the 216 * transition should be aborted. Moreover, if such an event occurs when the 217 * system is in the working state, an attempt to start a transition to the 218 * given sleep state should fail during certain period after the detection of 219 * the event. Using the 'state' attribute alone is not sufficient to satisfy 220 * these requirements, because a wakeup event may occur exactly when 'state' 221 * is being written to and may be delivered to user space right before it is 222 * frozen, so the event will remain only partially processed until the system is 223 * woken up by another event. In particular, it won't cause the transition to 224 * a sleep state to be aborted. 225 * 226 * This difficulty may be overcome if user space uses 'wakeup_count' before 227 * writing to 'state'. It first should read from 'wakeup_count' and store 228 * the read value. Then, after carrying out its own preparations for the system 229 * transition to a sleep state, it should write the stored value to 230 * 'wakeup_count'. If that fails, at least one wakeup event has occured since 231 * 'wakeup_count' was read and 'state' should not be written to. Otherwise, it 232 * is allowed to write to 'state', but the transition will be aborted if there 233 * are any wakeup events detected after 'wakeup_count' was written to. 234 */ 235 236static ssize_t wakeup_count_show(struct kobject *kobj, 237 struct kobj_attribute *attr, 238 char *buf) 239{ 240 unsigned long val; 241 242 return pm_get_wakeup_count(&val) ? sprintf(buf, "%lu\n", val) : -EINTR; 243} 244 245static ssize_t wakeup_count_store(struct kobject *kobj, 246 struct kobj_attribute *attr, 247 const char *buf, size_t n) 248{ 249 unsigned long val; 250 251 if (sscanf(buf, "%lu", &val) == 1) { 252 if (pm_save_wakeup_count(val)) 253 return n; 254 } 255 return -EINVAL; 256} 257 258power_attr(wakeup_count); 259#endif /* CONFIG_PM_SLEEP */ 260 261#ifdef CONFIG_PM_TRACE 262int pm_trace_enabled; 263 264static ssize_t pm_trace_show(struct kobject *kobj, struct kobj_attribute *attr, 265 char *buf) 266{ 267 return sprintf(buf, "%d\n", pm_trace_enabled); 268} 269 270static ssize_t 271pm_trace_store(struct kobject *kobj, struct kobj_attribute *attr, 272 const char *buf, size_t n) 273{ 274 int val; 275 276 if (sscanf(buf, "%d", &val) == 1) { 277 pm_trace_enabled = !!val; 278 return n; 279 } 280 return -EINVAL; 281} 282 283power_attr(pm_trace); 284#endif /* CONFIG_PM_TRACE */ 285 286static struct attribute * g[] = { 287 &state_attr.attr, 288#ifdef CONFIG_PM_TRACE 289 &pm_trace_attr.attr, 290#endif 291#ifdef CONFIG_PM_SLEEP 292 &pm_async_attr.attr, 293 &wakeup_count_attr.attr, 294#ifdef CONFIG_PM_DEBUG 295 &pm_test_attr.attr, 296#endif 297#endif 298 NULL, 299}; 300 301static struct attribute_group attr_group = { 302 .attrs = g, 303}; 304 305#ifdef CONFIG_PM_RUNTIME 306struct workqueue_struct *pm_wq; 307EXPORT_SYMBOL_GPL(pm_wq); 308 309static int __init pm_start_workqueue(void) 310{ 311 pm_wq = create_freezeable_workqueue("pm"); 312 313 return pm_wq ? 0 : -ENOMEM; 314} 315#else 316static inline int pm_start_workqueue(void) { return 0; } 317#endif 318 319static int __init pm_init(void) 320{ 321 int error = pm_start_workqueue(); 322 if (error) 323 return error; 324 power_kobj = kobject_create_and_add("power", NULL); 325 if (!power_kobj) 326 return -ENOMEM; 327 return sysfs_create_group(power_kobj, &attr_group); 328} 329 330core_initcall(pm_init); 331