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/export.h> 12 #include <linux/kobject.h> 13 #include <linux/string.h> 14 #include <linux/resume-trace.h> 15 #include <linux/workqueue.h> 16 #include <linux/debugfs.h> 17 #include <linux/seq_file.h> 18 19 #include "power.h" 20 21 DEFINE_MUTEX(pm_mutex); 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 int ret = blocking_notifier_call_chain(&pm_chain_head, val, NULL); 44 45 return notifier_to_errno(ret); 46 } 47 48 /* If set, devices may be suspended and resumed asynchronously. */ 49 int pm_async_enabled = 1; 50 51 static ssize_t pm_async_show(struct kobject *kobj, struct kobj_attribute *attr, 52 char *buf) 53 { 54 return sprintf(buf, "%d\n", pm_async_enabled); 55 } 56 57 static ssize_t pm_async_store(struct kobject *kobj, struct kobj_attribute *attr, 58 const char *buf, size_t n) 59 { 60 unsigned long val; 61 62 if (strict_strtoul(buf, 10, &val)) 63 return -EINVAL; 64 65 if (val > 1) 66 return -EINVAL; 67 68 pm_async_enabled = val; 69 return n; 70 } 71 72 power_attr(pm_async); 73 74 #ifdef CONFIG_PM_DEBUG 75 int pm_test_level = TEST_NONE; 76 77 static const char * const pm_tests[__TEST_AFTER_LAST] = { 78 [TEST_NONE] = "none", 79 [TEST_CORE] = "core", 80 [TEST_CPUS] = "processors", 81 [TEST_PLATFORM] = "platform", 82 [TEST_DEVICES] = "devices", 83 [TEST_FREEZER] = "freezer", 84 }; 85 86 static ssize_t pm_test_show(struct kobject *kobj, struct kobj_attribute *attr, 87 char *buf) 88 { 89 char *s = buf; 90 int level; 91 92 for (level = TEST_FIRST; level <= TEST_MAX; level++) 93 if (pm_tests[level]) { 94 if (level == pm_test_level) 95 s += sprintf(s, "[%s] ", pm_tests[level]); 96 else 97 s += sprintf(s, "%s ", pm_tests[level]); 98 } 99 100 if (s != buf) 101 /* convert the last space to a newline */ 102 *(s-1) = '\n'; 103 104 return (s - buf); 105 } 106 107 static ssize_t pm_test_store(struct kobject *kobj, struct kobj_attribute *attr, 108 const char *buf, size_t n) 109 { 110 const char * const *s; 111 int level; 112 char *p; 113 int len; 114 int error = -EINVAL; 115 116 p = memchr(buf, '\n', n); 117 len = p ? p - buf : n; 118 119 mutex_lock(&pm_mutex); 120 121 level = TEST_FIRST; 122 for (s = &pm_tests[level]; level <= TEST_MAX; s++, level++) 123 if (*s && len == strlen(*s) && !strncmp(buf, *s, len)) { 124 pm_test_level = level; 125 error = 0; 126 break; 127 } 128 129 mutex_unlock(&pm_mutex); 130 131 return error ? error : n; 132 } 133 134 power_attr(pm_test); 135 #endif /* CONFIG_PM_DEBUG */ 136 137 #ifdef CONFIG_DEBUG_FS 138 static char *suspend_step_name(enum suspend_stat_step step) 139 { 140 switch (step) { 141 case SUSPEND_FREEZE: 142 return "freeze"; 143 case SUSPEND_PREPARE: 144 return "prepare"; 145 case SUSPEND_SUSPEND: 146 return "suspend"; 147 case SUSPEND_SUSPEND_NOIRQ: 148 return "suspend_noirq"; 149 case SUSPEND_RESUME_NOIRQ: 150 return "resume_noirq"; 151 case SUSPEND_RESUME: 152 return "resume"; 153 default: 154 return ""; 155 } 156 } 157 158 static int suspend_stats_show(struct seq_file *s, void *unused) 159 { 160 int i, index, last_dev, last_errno, last_step; 161 162 last_dev = suspend_stats.last_failed_dev + REC_FAILED_NUM - 1; 163 last_dev %= REC_FAILED_NUM; 164 last_errno = suspend_stats.last_failed_errno + REC_FAILED_NUM - 1; 165 last_errno %= REC_FAILED_NUM; 166 last_step = suspend_stats.last_failed_step + REC_FAILED_NUM - 1; 167 last_step %= REC_FAILED_NUM; 168 seq_printf(s, "%s: %d\n%s: %d\n%s: %d\n%s: %d\n" 169 "%s: %d\n%s: %d\n%s: %d\n%s: %d\n", 170 "success", suspend_stats.success, 171 "fail", suspend_stats.fail, 172 "failed_freeze", suspend_stats.failed_freeze, 173 "failed_prepare", suspend_stats.failed_prepare, 174 "failed_suspend", suspend_stats.failed_suspend, 175 "failed_suspend_noirq", 176 suspend_stats.failed_suspend_noirq, 177 "failed_resume", suspend_stats.failed_resume, 178 "failed_resume_noirq", 179 suspend_stats.failed_resume_noirq); 180 seq_printf(s, "failures:\n last_failed_dev:\t%-s\n", 181 suspend_stats.failed_devs[last_dev]); 182 for (i = 1; i < REC_FAILED_NUM; i++) { 183 index = last_dev + REC_FAILED_NUM - i; 184 index %= REC_FAILED_NUM; 185 seq_printf(s, "\t\t\t%-s\n", 186 suspend_stats.failed_devs[index]); 187 } 188 seq_printf(s, " last_failed_errno:\t%-d\n", 189 suspend_stats.errno[last_errno]); 190 for (i = 1; i < REC_FAILED_NUM; i++) { 191 index = last_errno + REC_FAILED_NUM - i; 192 index %= REC_FAILED_NUM; 193 seq_printf(s, "\t\t\t%-d\n", 194 suspend_stats.errno[index]); 195 } 196 seq_printf(s, " last_failed_step:\t%-s\n", 197 suspend_step_name( 198 suspend_stats.failed_steps[last_step])); 199 for (i = 1; i < REC_FAILED_NUM; i++) { 200 index = last_step + REC_FAILED_NUM - i; 201 index %= REC_FAILED_NUM; 202 seq_printf(s, "\t\t\t%-s\n", 203 suspend_step_name( 204 suspend_stats.failed_steps[index])); 205 } 206 207 return 0; 208 } 209 210 static int suspend_stats_open(struct inode *inode, struct file *file) 211 { 212 return single_open(file, suspend_stats_show, NULL); 213 } 214 215 static const struct file_operations suspend_stats_operations = { 216 .open = suspend_stats_open, 217 .read = seq_read, 218 .llseek = seq_lseek, 219 .release = single_release, 220 }; 221 222 static int __init pm_debugfs_init(void) 223 { 224 debugfs_create_file("suspend_stats", S_IFREG | S_IRUGO, 225 NULL, NULL, &suspend_stats_operations); 226 return 0; 227 } 228 229 late_initcall(pm_debugfs_init); 230 #endif /* CONFIG_DEBUG_FS */ 231 232 #endif /* CONFIG_PM_SLEEP */ 233 234 struct kobject *power_kobj; 235 236 /** 237 * state - control system power state. 238 * 239 * show() returns what states are supported, which is hard-coded to 240 * 'standby' (Power-On Suspend), 'mem' (Suspend-to-RAM), and 241 * 'disk' (Suspend-to-Disk). 242 * 243 * store() accepts one of those strings, translates it into the 244 * proper enumerated value, and initiates a suspend transition. 245 */ 246 static ssize_t state_show(struct kobject *kobj, struct kobj_attribute *attr, 247 char *buf) 248 { 249 char *s = buf; 250 #ifdef CONFIG_SUSPEND 251 int i; 252 253 for (i = 0; i < PM_SUSPEND_MAX; i++) { 254 if (pm_states[i] && valid_state(i)) 255 s += sprintf(s,"%s ", pm_states[i]); 256 } 257 #endif 258 #ifdef CONFIG_HIBERNATION 259 s += sprintf(s, "%s\n", "disk"); 260 #else 261 if (s != buf) 262 /* convert the last space to a newline */ 263 *(s-1) = '\n'; 264 #endif 265 return (s - buf); 266 } 267 268 static ssize_t state_store(struct kobject *kobj, struct kobj_attribute *attr, 269 const char *buf, size_t n) 270 { 271 #ifdef CONFIG_SUSPEND 272 suspend_state_t state = PM_SUSPEND_STANDBY; 273 const char * const *s; 274 #endif 275 char *p; 276 int len; 277 int error = -EINVAL; 278 279 p = memchr(buf, '\n', n); 280 len = p ? p - buf : n; 281 282 /* First, check if we are requested to hibernate */ 283 if (len == 4 && !strncmp(buf, "disk", len)) { 284 error = hibernate(); 285 goto Exit; 286 } 287 288 #ifdef CONFIG_SUSPEND 289 for (s = &pm_states[state]; state < PM_SUSPEND_MAX; s++, state++) { 290 if (*s && len == strlen(*s) && !strncmp(buf, *s, len)) 291 break; 292 } 293 if (state < PM_SUSPEND_MAX && *s) 294 error = enter_state(state); 295 if (error) { 296 suspend_stats.fail++; 297 dpm_save_failed_errno(error); 298 } else 299 suspend_stats.success++; 300 #endif 301 302 Exit: 303 return error ? error : n; 304 } 305 306 power_attr(state); 307 308 #ifdef CONFIG_PM_SLEEP 309 /* 310 * The 'wakeup_count' attribute, along with the functions defined in 311 * drivers/base/power/wakeup.c, provides a means by which wakeup events can be 312 * handled in a non-racy way. 313 * 314 * If a wakeup event occurs when the system is in a sleep state, it simply is 315 * woken up. In turn, if an event that would wake the system up from a sleep 316 * state occurs when it is undergoing a transition to that sleep state, the 317 * transition should be aborted. Moreover, if such an event occurs when the 318 * system is in the working state, an attempt to start a transition to the 319 * given sleep state should fail during certain period after the detection of 320 * the event. Using the 'state' attribute alone is not sufficient to satisfy 321 * these requirements, because a wakeup event may occur exactly when 'state' 322 * is being written to and may be delivered to user space right before it is 323 * frozen, so the event will remain only partially processed until the system is 324 * woken up by another event. In particular, it won't cause the transition to 325 * a sleep state to be aborted. 326 * 327 * This difficulty may be overcome if user space uses 'wakeup_count' before 328 * writing to 'state'. It first should read from 'wakeup_count' and store 329 * the read value. Then, after carrying out its own preparations for the system 330 * transition to a sleep state, it should write the stored value to 331 * 'wakeup_count'. If that fails, at least one wakeup event has occurred since 332 * 'wakeup_count' was read and 'state' should not be written to. Otherwise, it 333 * is allowed to write to 'state', but the transition will be aborted if there 334 * are any wakeup events detected after 'wakeup_count' was written to. 335 */ 336 337 static ssize_t wakeup_count_show(struct kobject *kobj, 338 struct kobj_attribute *attr, 339 char *buf) 340 { 341 unsigned int val; 342 343 return pm_get_wakeup_count(&val) ? sprintf(buf, "%u\n", val) : -EINTR; 344 } 345 346 static ssize_t wakeup_count_store(struct kobject *kobj, 347 struct kobj_attribute *attr, 348 const char *buf, size_t n) 349 { 350 unsigned int val; 351 352 if (sscanf(buf, "%u", &val) == 1) { 353 if (pm_save_wakeup_count(val)) 354 return n; 355 } 356 return -EINVAL; 357 } 358 359 power_attr(wakeup_count); 360 #endif /* CONFIG_PM_SLEEP */ 361 362 #ifdef CONFIG_PM_TRACE 363 int pm_trace_enabled; 364 365 static ssize_t pm_trace_show(struct kobject *kobj, struct kobj_attribute *attr, 366 char *buf) 367 { 368 return sprintf(buf, "%d\n", pm_trace_enabled); 369 } 370 371 static ssize_t 372 pm_trace_store(struct kobject *kobj, struct kobj_attribute *attr, 373 const char *buf, size_t n) 374 { 375 int val; 376 377 if (sscanf(buf, "%d", &val) == 1) { 378 pm_trace_enabled = !!val; 379 return n; 380 } 381 return -EINVAL; 382 } 383 384 power_attr(pm_trace); 385 386 static ssize_t pm_trace_dev_match_show(struct kobject *kobj, 387 struct kobj_attribute *attr, 388 char *buf) 389 { 390 return show_trace_dev_match(buf, PAGE_SIZE); 391 } 392 393 static ssize_t 394 pm_trace_dev_match_store(struct kobject *kobj, struct kobj_attribute *attr, 395 const char *buf, size_t n) 396 { 397 return -EINVAL; 398 } 399 400 power_attr(pm_trace_dev_match); 401 402 #endif /* CONFIG_PM_TRACE */ 403 404 static struct attribute * g[] = { 405 &state_attr.attr, 406 #ifdef CONFIG_PM_TRACE 407 &pm_trace_attr.attr, 408 &pm_trace_dev_match_attr.attr, 409 #endif 410 #ifdef CONFIG_PM_SLEEP 411 &pm_async_attr.attr, 412 &wakeup_count_attr.attr, 413 #ifdef CONFIG_PM_DEBUG 414 &pm_test_attr.attr, 415 #endif 416 #endif 417 NULL, 418 }; 419 420 static struct attribute_group attr_group = { 421 .attrs = g, 422 }; 423 424 #ifdef CONFIG_PM_RUNTIME 425 struct workqueue_struct *pm_wq; 426 EXPORT_SYMBOL_GPL(pm_wq); 427 428 static int __init pm_start_workqueue(void) 429 { 430 pm_wq = alloc_workqueue("pm", WQ_FREEZABLE, 0); 431 432 return pm_wq ? 0 : -ENOMEM; 433 } 434 #else 435 static inline int pm_start_workqueue(void) { return 0; } 436 #endif 437 438 static int __init pm_init(void) 439 { 440 int error = pm_start_workqueue(); 441 if (error) 442 return error; 443 hibernate_image_size_init(); 444 hibernate_reserved_size_init(); 445 power_kobj = kobject_create_and_add("power", NULL); 446 if (!power_kobj) 447 return -ENOMEM; 448 return sysfs_create_group(power_kobj, &attr_group); 449 } 450 451 core_initcall(pm_init); 452