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 #ifdef CONFIG_PM_SLEEP 21 22 /* Routines for PM-transition notifications */ 23 24 static BLOCKING_NOTIFIER_HEAD(pm_chain_head); 25 26 int register_pm_notifier(struct notifier_block *nb) 27 { 28 return blocking_notifier_chain_register(&pm_chain_head, nb); 29 } 30 EXPORT_SYMBOL_GPL(register_pm_notifier); 31 32 int unregister_pm_notifier(struct notifier_block *nb) 33 { 34 return blocking_notifier_chain_unregister(&pm_chain_head, nb); 35 } 36 EXPORT_SYMBOL_GPL(unregister_pm_notifier); 37 38 int pm_notifier_call_chain(unsigned long val) 39 { 40 return (blocking_notifier_call_chain(&pm_chain_head, val, NULL) 41 == NOTIFY_BAD) ? -EINVAL : 0; 42 } 43 44 /* If set, devices may be suspended and resumed asynchronously. */ 45 int pm_async_enabled = 1; 46 47 static ssize_t pm_async_show(struct kobject *kobj, struct kobj_attribute *attr, 48 char *buf) 49 { 50 return sprintf(buf, "%d\n", pm_async_enabled); 51 } 52 53 static ssize_t pm_async_store(struct kobject *kobj, struct kobj_attribute *attr, 54 const char *buf, size_t n) 55 { 56 unsigned long val; 57 58 if (strict_strtoul(buf, 10, &val)) 59 return -EINVAL; 60 61 if (val > 1) 62 return -EINVAL; 63 64 pm_async_enabled = val; 65 return n; 66 } 67 68 power_attr(pm_async); 69 70 #ifdef CONFIG_PM_DEBUG 71 int pm_test_level = TEST_NONE; 72 73 static const char * const pm_tests[__TEST_AFTER_LAST] = { 74 [TEST_NONE] = "none", 75 [TEST_CORE] = "core", 76 [TEST_CPUS] = "processors", 77 [TEST_PLATFORM] = "platform", 78 [TEST_DEVICES] = "devices", 79 [TEST_FREEZER] = "freezer", 80 }; 81 82 static ssize_t pm_test_show(struct kobject *kobj, struct kobj_attribute *attr, 83 char *buf) 84 { 85 char *s = buf; 86 int level; 87 88 for (level = TEST_FIRST; level <= TEST_MAX; level++) 89 if (pm_tests[level]) { 90 if (level == pm_test_level) 91 s += sprintf(s, "[%s] ", pm_tests[level]); 92 else 93 s += sprintf(s, "%s ", pm_tests[level]); 94 } 95 96 if (s != buf) 97 /* convert the last space to a newline */ 98 *(s-1) = '\n'; 99 100 return (s - buf); 101 } 102 103 static ssize_t pm_test_store(struct kobject *kobj, struct kobj_attribute *attr, 104 const char *buf, size_t n) 105 { 106 const char * const *s; 107 int level; 108 char *p; 109 int len; 110 int error = -EINVAL; 111 112 p = memchr(buf, '\n', n); 113 len = p ? p - buf : n; 114 115 mutex_lock(&pm_mutex); 116 117 level = TEST_FIRST; 118 for (s = &pm_tests[level]; level <= TEST_MAX; s++, level++) 119 if (*s && len == strlen(*s) && !strncmp(buf, *s, len)) { 120 pm_test_level = level; 121 error = 0; 122 break; 123 } 124 125 mutex_unlock(&pm_mutex); 126 127 return error ? error : n; 128 } 129 130 power_attr(pm_test); 131 #endif /* CONFIG_PM_DEBUG */ 132 133 #endif /* CONFIG_PM_SLEEP */ 134 135 struct kobject *power_kobj; 136 137 /** 138 * state - control system power state. 139 * 140 * show() returns what states are supported, which is hard-coded to 141 * 'standby' (Power-On Suspend), 'mem' (Suspend-to-RAM), and 142 * 'disk' (Suspend-to-Disk). 143 * 144 * store() accepts one of those strings, translates it into the 145 * proper enumerated value, and initiates a suspend transition. 146 */ 147 static ssize_t state_show(struct kobject *kobj, struct kobj_attribute *attr, 148 char *buf) 149 { 150 char *s = buf; 151 #ifdef CONFIG_SUSPEND 152 int i; 153 154 for (i = 0; i < PM_SUSPEND_MAX; i++) { 155 if (pm_states[i] && valid_state(i)) 156 s += sprintf(s,"%s ", pm_states[i]); 157 } 158 #endif 159 #ifdef CONFIG_HIBERNATION 160 s += sprintf(s, "%s\n", "disk"); 161 #else 162 if (s != buf) 163 /* convert the last space to a newline */ 164 *(s-1) = '\n'; 165 #endif 166 return (s - buf); 167 } 168 169 static ssize_t state_store(struct kobject *kobj, struct kobj_attribute *attr, 170 const char *buf, size_t n) 171 { 172 #ifdef CONFIG_SUSPEND 173 suspend_state_t state = PM_SUSPEND_STANDBY; 174 const char * const *s; 175 #endif 176 char *p; 177 int len; 178 int error = -EINVAL; 179 180 p = memchr(buf, '\n', n); 181 len = p ? p - buf : n; 182 183 /* First, check if we are requested to hibernate */ 184 if (len == 4 && !strncmp(buf, "disk", len)) { 185 error = hibernate(); 186 goto Exit; 187 } 188 189 #ifdef CONFIG_SUSPEND 190 for (s = &pm_states[state]; state < PM_SUSPEND_MAX; s++, state++) { 191 if (*s && len == strlen(*s) && !strncmp(buf, *s, len)) 192 break; 193 } 194 if (state < PM_SUSPEND_MAX && *s) 195 error = enter_state(state); 196 #endif 197 198 Exit: 199 return error ? error : n; 200 } 201 202 power_attr(state); 203 204 #ifdef CONFIG_PM_SLEEP 205 /* 206 * The 'wakeup_count' attribute, along with the functions defined in 207 * drivers/base/power/wakeup.c, provides a means by which wakeup events can be 208 * handled in a non-racy way. 209 * 210 * If a wakeup event occurs when the system is in a sleep state, it simply is 211 * woken up. In turn, if an event that would wake the system up from a sleep 212 * state occurs when it is undergoing a transition to that sleep state, the 213 * transition should be aborted. Moreover, if such an event occurs when the 214 * system is in the working state, an attempt to start a transition to the 215 * given sleep state should fail during certain period after the detection of 216 * the event. Using the 'state' attribute alone is not sufficient to satisfy 217 * these requirements, because a wakeup event may occur exactly when 'state' 218 * is being written to and may be delivered to user space right before it is 219 * frozen, so the event will remain only partially processed until the system is 220 * woken up by another event. In particular, it won't cause the transition to 221 * a sleep state to be aborted. 222 * 223 * This difficulty may be overcome if user space uses 'wakeup_count' before 224 * writing to 'state'. It first should read from 'wakeup_count' and store 225 * the read value. Then, after carrying out its own preparations for the system 226 * transition to a sleep state, it should write the stored value to 227 * 'wakeup_count'. If that fails, at least one wakeup event has occured since 228 * 'wakeup_count' was read and 'state' should not be written to. Otherwise, it 229 * is allowed to write to 'state', but the transition will be aborted if there 230 * are any wakeup events detected after 'wakeup_count' was written to. 231 */ 232 233 static ssize_t wakeup_count_show(struct kobject *kobj, 234 struct kobj_attribute *attr, 235 char *buf) 236 { 237 unsigned int val; 238 239 return pm_get_wakeup_count(&val) ? sprintf(buf, "%u\n", val) : -EINTR; 240 } 241 242 static ssize_t wakeup_count_store(struct kobject *kobj, 243 struct kobj_attribute *attr, 244 const char *buf, size_t n) 245 { 246 unsigned int val; 247 248 if (sscanf(buf, "%u", &val) == 1) { 249 if (pm_save_wakeup_count(val)) 250 return n; 251 } 252 return -EINVAL; 253 } 254 255 power_attr(wakeup_count); 256 #endif /* CONFIG_PM_SLEEP */ 257 258 #ifdef CONFIG_PM_TRACE 259 int pm_trace_enabled; 260 261 static ssize_t pm_trace_show(struct kobject *kobj, struct kobj_attribute *attr, 262 char *buf) 263 { 264 return sprintf(buf, "%d\n", pm_trace_enabled); 265 } 266 267 static ssize_t 268 pm_trace_store(struct kobject *kobj, struct kobj_attribute *attr, 269 const char *buf, size_t n) 270 { 271 int val; 272 273 if (sscanf(buf, "%d", &val) == 1) { 274 pm_trace_enabled = !!val; 275 return n; 276 } 277 return -EINVAL; 278 } 279 280 power_attr(pm_trace); 281 282 static ssize_t pm_trace_dev_match_show(struct kobject *kobj, 283 struct kobj_attribute *attr, 284 char *buf) 285 { 286 return show_trace_dev_match(buf, PAGE_SIZE); 287 } 288 289 static ssize_t 290 pm_trace_dev_match_store(struct kobject *kobj, struct kobj_attribute *attr, 291 const char *buf, size_t n) 292 { 293 return -EINVAL; 294 } 295 296 power_attr(pm_trace_dev_match); 297 298 #endif /* CONFIG_PM_TRACE */ 299 300 static struct attribute * g[] = { 301 &state_attr.attr, 302 #ifdef CONFIG_PM_TRACE 303 &pm_trace_attr.attr, 304 &pm_trace_dev_match_attr.attr, 305 #endif 306 #ifdef CONFIG_PM_SLEEP 307 &pm_async_attr.attr, 308 &wakeup_count_attr.attr, 309 #ifdef CONFIG_PM_DEBUG 310 &pm_test_attr.attr, 311 #endif 312 #endif 313 NULL, 314 }; 315 316 static struct attribute_group attr_group = { 317 .attrs = g, 318 }; 319 320 #ifdef CONFIG_PM_RUNTIME 321 struct workqueue_struct *pm_wq; 322 EXPORT_SYMBOL_GPL(pm_wq); 323 324 static int __init pm_start_workqueue(void) 325 { 326 pm_wq = alloc_workqueue("pm", WQ_FREEZABLE, 0); 327 328 return pm_wq ? 0 : -ENOMEM; 329 } 330 #else 331 static inline int pm_start_workqueue(void) { return 0; } 332 #endif 333 334 static int __init pm_init(void) 335 { 336 int error = pm_start_workqueue(); 337 if (error) 338 return error; 339 hibernate_image_size_init(); 340 power_kobj = kobject_create_and_add("power", NULL); 341 if (!power_kobj) 342 return -ENOMEM; 343 return sysfs_create_group(power_kobj, &attr_group); 344 } 345 346 core_initcall(pm_init); 347