| 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 occurred 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); |