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 int ret = blocking_notifier_call_chain(&pm_chain_head, val, NULL); 41 42 return notifier_to_errno(ret); 43 } 44 45 /* If set, devices may be suspended and resumed asynchronously. */ 46 int pm_async_enabled = 1; 47 48 static ssize_t pm_async_show(struct kobject *kobj, struct kobj_attribute *attr, 49 char *buf) 50 { 51 return sprintf(buf, "%d\n", pm_async_enabled); 52 } 53 54 static ssize_t pm_async_store(struct kobject *kobj, struct kobj_attribute *attr, 55 const char *buf, size_t n) 56 { 57 unsigned long val; 58 59 if (strict_strtoul(buf, 10, &val)) 60 return -EINVAL; 61 62 if (val > 1) 63 return -EINVAL; 64 65 pm_async_enabled = val; 66 return n; 67 } 68 69 power_attr(pm_async); 70 71 #ifdef CONFIG_PM_DEBUG 72 int pm_test_level = TEST_NONE; 73 74 static const char * const pm_tests[__TEST_AFTER_LAST] = { 75 [TEST_NONE] = "none", 76 [TEST_CORE] = "core", 77 [TEST_CPUS] = "processors", 78 [TEST_PLATFORM] = "platform", 79 [TEST_DEVICES] = "devices", 80 [TEST_FREEZER] = "freezer", 81 }; 82 83 static ssize_t pm_test_show(struct kobject *kobj, struct kobj_attribute *attr, 84 char *buf) 85 { 86 char *s = buf; 87 int level; 88 89 for (level = TEST_FIRST; level <= TEST_MAX; level++) 90 if (pm_tests[level]) { 91 if (level == pm_test_level) 92 s += sprintf(s, "[%s] ", pm_tests[level]); 93 else 94 s += sprintf(s, "%s ", pm_tests[level]); 95 } 96 97 if (s != buf) 98 /* convert the last space to a newline */ 99 *(s-1) = '\n'; 100 101 return (s - buf); 102 } 103 104 static ssize_t pm_test_store(struct kobject *kobj, struct kobj_attribute *attr, 105 const char *buf, size_t n) 106 { 107 const char * const *s; 108 int level; 109 char *p; 110 int len; 111 int error = -EINVAL; 112 113 p = memchr(buf, '\n', n); 114 len = p ? p - buf : n; 115 116 mutex_lock(&pm_mutex); 117 118 level = TEST_FIRST; 119 for (s = &pm_tests[level]; level <= TEST_MAX; s++, level++) 120 if (*s && len == strlen(*s) && !strncmp(buf, *s, len)) { 121 pm_test_level = level; 122 error = 0; 123 break; 124 } 125 126 mutex_unlock(&pm_mutex); 127 128 return error ? error : n; 129 } 130 131 power_attr(pm_test); 132 #endif /* CONFIG_PM_DEBUG */ 133 134 #endif /* CONFIG_PM_SLEEP */ 135 136 struct kobject *power_kobj; 137 138 /** 139 * state - control system power state. 140 * 141 * show() returns what states are supported, which is hard-coded to 142 * 'standby' (Power-On Suspend), 'mem' (Suspend-to-RAM), and 143 * 'disk' (Suspend-to-Disk). 144 * 145 * store() accepts one of those strings, translates it into the 146 * proper enumerated value, and initiates a suspend transition. 147 */ 148 static ssize_t state_show(struct kobject *kobj, struct kobj_attribute *attr, 149 char *buf) 150 { 151 char *s = buf; 152 #ifdef CONFIG_SUSPEND 153 int i; 154 155 for (i = 0; i < PM_SUSPEND_MAX; i++) { 156 if (pm_states[i] && valid_state(i)) 157 s += sprintf(s,"%s ", pm_states[i]); 158 } 159 #endif 160 #ifdef CONFIG_HIBERNATION 161 s += sprintf(s, "%s\n", "disk"); 162 #else 163 if (s != buf) 164 /* convert the last space to a newline */ 165 *(s-1) = '\n'; 166 #endif 167 return (s - buf); 168 } 169 170 static ssize_t state_store(struct kobject *kobj, struct kobj_attribute *attr, 171 const char *buf, size_t n) 172 { 173 #ifdef CONFIG_SUSPEND 174 suspend_state_t state = PM_SUSPEND_STANDBY; 175 const char * const *s; 176 #endif 177 char *p; 178 int len; 179 int error = -EINVAL; 180 181 p = memchr(buf, '\n', n); 182 len = p ? p - buf : n; 183 184 /* First, check if we are requested to hibernate */ 185 if (len == 4 && !strncmp(buf, "disk", len)) { 186 error = hibernate(); 187 goto Exit; 188 } 189 190 #ifdef CONFIG_SUSPEND 191 for (s = &pm_states[state]; state < PM_SUSPEND_MAX; s++, state++) { 192 if (*s && len == strlen(*s) && !strncmp(buf, *s, len)) 193 break; 194 } 195 if (state < PM_SUSPEND_MAX && *s) 196 error = enter_state(state); 197 #endif 198 199 Exit: 200 return error ? error : n; 201 } 202 203 power_attr(state); 204 205 #ifdef CONFIG_PM_SLEEP 206 /* 207 * The 'wakeup_count' attribute, along with the functions defined in 208 * drivers/base/power/wakeup.c, provides a means by which wakeup events can be 209 * handled in a non-racy way. 210 * 211 * If a wakeup event occurs when the system is in a sleep state, it simply is 212 * woken up. In turn, if an event that would wake the system up from a sleep 213 * state occurs when it is undergoing a transition to that sleep state, the 214 * transition should be aborted. Moreover, if such an event occurs when the 215 * system is in the working state, an attempt to start a transition to the 216 * given sleep state should fail during certain period after the detection of 217 * the event. Using the 'state' attribute alone is not sufficient to satisfy 218 * these requirements, because a wakeup event may occur exactly when 'state' 219 * is being written to and may be delivered to user space right before it is 220 * frozen, so the event will remain only partially processed until the system is 221 * woken up by another event. In particular, it won't cause the transition to 222 * a sleep state to be aborted. 223 * 224 * This difficulty may be overcome if user space uses 'wakeup_count' before 225 * writing to 'state'. It first should read from 'wakeup_count' and store 226 * the read value. Then, after carrying out its own preparations for the system 227 * transition to a sleep state, it should write the stored value to 228 * 'wakeup_count'. If that fails, at least one wakeup event has occurred since 229 * 'wakeup_count' was read and 'state' should not be written to. Otherwise, it 230 * is allowed to write to 'state', but the transition will be aborted if there 231 * are any wakeup events detected after 'wakeup_count' was written to. 232 */ 233 234 static ssize_t wakeup_count_show(struct kobject *kobj, 235 struct kobj_attribute *attr, 236 char *buf) 237 { 238 unsigned int val; 239 240 return pm_get_wakeup_count(&val) ? sprintf(buf, "%u\n", val) : -EINTR; 241 } 242 243 static ssize_t wakeup_count_store(struct kobject *kobj, 244 struct kobj_attribute *attr, 245 const char *buf, size_t n) 246 { 247 unsigned int val; 248 249 if (sscanf(buf, "%u", &val) == 1) { 250 if (pm_save_wakeup_count(val)) 251 return n; 252 } 253 return -EINVAL; 254 } 255 256 power_attr(wakeup_count); 257 #endif /* CONFIG_PM_SLEEP */ 258 259 #ifdef CONFIG_PM_TRACE 260 int pm_trace_enabled; 261 262 static ssize_t pm_trace_show(struct kobject *kobj, struct kobj_attribute *attr, 263 char *buf) 264 { 265 return sprintf(buf, "%d\n", pm_trace_enabled); 266 } 267 268 static ssize_t 269 pm_trace_store(struct kobject *kobj, struct kobj_attribute *attr, 270 const char *buf, size_t n) 271 { 272 int val; 273 274 if (sscanf(buf, "%d", &val) == 1) { 275 pm_trace_enabled = !!val; 276 return n; 277 } 278 return -EINVAL; 279 } 280 281 power_attr(pm_trace); 282 283 static ssize_t pm_trace_dev_match_show(struct kobject *kobj, 284 struct kobj_attribute *attr, 285 char *buf) 286 { 287 return show_trace_dev_match(buf, PAGE_SIZE); 288 } 289 290 static ssize_t 291 pm_trace_dev_match_store(struct kobject *kobj, struct kobj_attribute *attr, 292 const char *buf, size_t n) 293 { 294 return -EINVAL; 295 } 296 297 power_attr(pm_trace_dev_match); 298 299 #endif /* CONFIG_PM_TRACE */ 300 301 static struct attribute * g[] = { 302 &state_attr.attr, 303 #ifdef CONFIG_PM_TRACE 304 &pm_trace_attr.attr, 305 &pm_trace_dev_match_attr.attr, 306 #endif 307 #ifdef CONFIG_PM_SLEEP 308 &pm_async_attr.attr, 309 &wakeup_count_attr.attr, 310 #ifdef CONFIG_PM_DEBUG 311 &pm_test_attr.attr, 312 #endif 313 #endif 314 NULL, 315 }; 316 317 static struct attribute_group attr_group = { 318 .attrs = g, 319 }; 320 321 #ifdef CONFIG_PM_RUNTIME 322 struct workqueue_struct *pm_wq; 323 EXPORT_SYMBOL_GPL(pm_wq); 324 325 static int __init pm_start_workqueue(void) 326 { 327 pm_wq = alloc_workqueue("pm", WQ_FREEZABLE, 0); 328 329 return pm_wq ? 0 : -ENOMEM; 330 } 331 #else 332 static inline int pm_start_workqueue(void) { return 0; } 333 #endif 334 335 static int __init pm_init(void) 336 { 337 int error = pm_start_workqueue(); 338 if (error) 339 return error; 340 hibernate_image_size_init(); 341 hibernate_reserved_size_init(); 342 power_kobj = kobject_create_and_add("power", NULL); 343 if (!power_kobj) 344 return -ENOMEM; 345 return sysfs_create_group(power_kobj, &attr_group); 346 } 347 348 core_initcall(pm_init); 349