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 #include <linux/debugfs.h> 16 #include <linux/seq_file.h> 17 18 #include "power.h" 19 20 DEFINE_MUTEX(pm_mutex); 21 22 #ifdef CONFIG_PM_SLEEP 23 24 /* Routines for PM-transition notifications */ 25 26 static BLOCKING_NOTIFIER_HEAD(pm_chain_head); 27 28 int register_pm_notifier(struct notifier_block *nb) 29 { 30 return blocking_notifier_chain_register(&pm_chain_head, nb); 31 } 32 EXPORT_SYMBOL_GPL(register_pm_notifier); 33 34 int unregister_pm_notifier(struct notifier_block *nb) 35 { 36 return blocking_notifier_chain_unregister(&pm_chain_head, nb); 37 } 38 EXPORT_SYMBOL_GPL(unregister_pm_notifier); 39 40 int pm_notifier_call_chain(unsigned long val) 41 { 42 int ret = blocking_notifier_call_chain(&pm_chain_head, val, NULL); 43 44 return notifier_to_errno(ret); 45 } 46 47 /* If set, devices may be suspended and resumed asynchronously. */ 48 int pm_async_enabled = 1; 49 50 static 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 56 static 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 71 power_attr(pm_async); 72 73 #ifdef CONFIG_PM_DEBUG 74 int pm_test_level = TEST_NONE; 75 76 static 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 85 static 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 } 105 106 static 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 } 132 133 power_attr(pm_test); 134 #endif /* CONFIG_PM_DEBUG */ 135 136 #ifdef CONFIG_DEBUG_FS 137 static char *suspend_step_name(enum suspend_stat_step step) 138 { 139 switch (step) { 140 case SUSPEND_FREEZE: 141 return "freeze"; 142 case SUSPEND_PREPARE: 143 return "prepare"; 144 case SUSPEND_SUSPEND: 145 return "suspend"; 146 case SUSPEND_SUSPEND_NOIRQ: 147 return "suspend_noirq"; 148 case SUSPEND_RESUME_NOIRQ: 149 return "resume_noirq"; 150 case SUSPEND_RESUME: 151 return "resume"; 152 default: 153 return ""; 154 } 155 } 156 157 static int suspend_stats_show(struct seq_file *s, void *unused) 158 { 159 int i, index, last_dev, last_errno, last_step; 160 161 last_dev = suspend_stats.last_failed_dev + REC_FAILED_NUM - 1; 162 last_dev %= REC_FAILED_NUM; 163 last_errno = suspend_stats.last_failed_errno + REC_FAILED_NUM - 1; 164 last_errno %= REC_FAILED_NUM; 165 last_step = suspend_stats.last_failed_step + REC_FAILED_NUM - 1; 166 last_step %= REC_FAILED_NUM; 167 seq_printf(s, "%s: %d\n%s: %d\n%s: %d\n%s: %d\n" 168 "%s: %d\n%s: %d\n%s: %d\n%s: %d\n", 169 "success", suspend_stats.success, 170 "fail", suspend_stats.fail, 171 "failed_freeze", suspend_stats.failed_freeze, 172 "failed_prepare", suspend_stats.failed_prepare, 173 "failed_suspend", suspend_stats.failed_suspend, 174 "failed_suspend_noirq", 175 suspend_stats.failed_suspend_noirq, 176 "failed_resume", suspend_stats.failed_resume, 177 "failed_resume_noirq", 178 suspend_stats.failed_resume_noirq); 179 seq_printf(s, "failures:\n last_failed_dev:\t%-s\n", 180 suspend_stats.failed_devs[last_dev]); 181 for (i = 1; i < REC_FAILED_NUM; i++) { 182 index = last_dev + REC_FAILED_NUM - i; 183 index %= REC_FAILED_NUM; 184 seq_printf(s, "\t\t\t%-s\n", 185 suspend_stats.failed_devs[index]); 186 } 187 seq_printf(s, " last_failed_errno:\t%-d\n", 188 suspend_stats.errno[last_errno]); 189 for (i = 1; i < REC_FAILED_NUM; i++) { 190 index = last_errno + REC_FAILED_NUM - i; 191 index %= REC_FAILED_NUM; 192 seq_printf(s, "\t\t\t%-d\n", 193 suspend_stats.errno[index]); 194 } 195 seq_printf(s, " last_failed_step:\t%-s\n", 196 suspend_step_name( 197 suspend_stats.failed_steps[last_step])); 198 for (i = 1; i < REC_FAILED_NUM; i++) { 199 index = last_step + REC_FAILED_NUM - i; 200 index %= REC_FAILED_NUM; 201 seq_printf(s, "\t\t\t%-s\n", 202 suspend_step_name( 203 suspend_stats.failed_steps[index])); 204 } 205 206 return 0; 207 } 208 209 static int suspend_stats_open(struct inode *inode, struct file *file) 210 { 211 return single_open(file, suspend_stats_show, NULL); 212 } 213 214 static const struct file_operations suspend_stats_operations = { 215 .open = suspend_stats_open, 216 .read = seq_read, 217 .llseek = seq_lseek, 218 .release = single_release, 219 }; 220 221 static int __init pm_debugfs_init(void) 222 { 223 debugfs_create_file("suspend_stats", S_IFREG | S_IRUGO, 224 NULL, NULL, &suspend_stats_operations); 225 return 0; 226 } 227 228 late_initcall(pm_debugfs_init); 229 #endif /* CONFIG_DEBUG_FS */ 230 231 #endif /* CONFIG_PM_SLEEP */ 232 233 struct kobject *power_kobj; 234 235 /** 236 * state - control system power state. 237 * 238 * show() returns what states are supported, which is hard-coded to 239 * 'standby' (Power-On Suspend), 'mem' (Suspend-to-RAM), and 240 * 'disk' (Suspend-to-Disk). 241 * 242 * store() accepts one of those strings, translates it into the 243 * proper enumerated value, and initiates a suspend transition. 244 */ 245 static ssize_t state_show(struct kobject *kobj, struct kobj_attribute *attr, 246 char *buf) 247 { 248 char *s = buf; 249 #ifdef CONFIG_SUSPEND 250 int i; 251 252 for (i = 0; i < PM_SUSPEND_MAX; i++) { 253 if (pm_states[i] && valid_state(i)) 254 s += sprintf(s,"%s ", pm_states[i]); 255 } 256 #endif 257 #ifdef CONFIG_HIBERNATION 258 s += sprintf(s, "%s\n", "disk"); 259 #else 260 if (s != buf) 261 /* convert the last space to a newline */ 262 *(s-1) = '\n'; 263 #endif 264 return (s - buf); 265 } 266 267 static ssize_t state_store(struct kobject *kobj, struct kobj_attribute *attr, 268 const char *buf, size_t n) 269 { 270 #ifdef CONFIG_SUSPEND 271 suspend_state_t state = PM_SUSPEND_STANDBY; 272 const char * const *s; 273 #endif 274 char *p; 275 int len; 276 int error = -EINVAL; 277 278 p = memchr(buf, '\n', n); 279 len = p ? p - buf : n; 280 281 /* First, check if we are requested to hibernate */ 282 if (len == 4 && !strncmp(buf, "disk", len)) { 283 error = hibernate(); 284 goto Exit; 285 } 286 287 #ifdef CONFIG_SUSPEND 288 for (s = &pm_states[state]; state < PM_SUSPEND_MAX; s++, state++) { 289 if (*s && len == strlen(*s) && !strncmp(buf, *s, len)) 290 break; 291 } 292 if (state < PM_SUSPEND_MAX && *s) 293 error = enter_state(state); 294 if (error) { 295 suspend_stats.fail++; 296 dpm_save_failed_errno(error); 297 } else 298 suspend_stats.success++; 299 #endif 300 301 Exit: 302 return error ? error : n; 303 } 304 305 power_attr(state); 306 307 #ifdef CONFIG_PM_SLEEP 308 /* 309 * The 'wakeup_count' attribute, along with the functions defined in 310 * drivers/base/power/wakeup.c, provides a means by which wakeup events can be 311 * handled in a non-racy way. 312 * 313 * If a wakeup event occurs when the system is in a sleep state, it simply is 314 * woken up. In turn, if an event that would wake the system up from a sleep 315 * state occurs when it is undergoing a transition to that sleep state, the 316 * transition should be aborted. Moreover, if such an event occurs when the 317 * system is in the working state, an attempt to start a transition to the 318 * given sleep state should fail during certain period after the detection of 319 * the event. Using the 'state' attribute alone is not sufficient to satisfy 320 * these requirements, because a wakeup event may occur exactly when 'state' 321 * is being written to and may be delivered to user space right before it is 322 * frozen, so the event will remain only partially processed until the system is 323 * woken up by another event. In particular, it won't cause the transition to 324 * a sleep state to be aborted. 325 * 326 * This difficulty may be overcome if user space uses 'wakeup_count' before 327 * writing to 'state'. It first should read from 'wakeup_count' and store 328 * the read value. Then, after carrying out its own preparations for the system 329 * transition to a sleep state, it should write the stored value to 330 * 'wakeup_count'. If that fails, at least one wakeup event has occurred since 331 * 'wakeup_count' was read and 'state' should not be written to. Otherwise, it 332 * is allowed to write to 'state', but the transition will be aborted if there 333 * are any wakeup events detected after 'wakeup_count' was written to. 334 */ 335 336 static ssize_t wakeup_count_show(struct kobject *kobj, 337 struct kobj_attribute *attr, 338 char *buf) 339 { 340 unsigned int val; 341 342 return pm_get_wakeup_count(&val) ? sprintf(buf, "%u\n", val) : -EINTR; 343 } 344 345 static ssize_t wakeup_count_store(struct kobject *kobj, 346 struct kobj_attribute *attr, 347 const char *buf, size_t n) 348 { 349 unsigned int val; 350 351 if (sscanf(buf, "%u", &val) == 1) { 352 if (pm_save_wakeup_count(val)) 353 return n; 354 } 355 return -EINVAL; 356 } 357 358 power_attr(wakeup_count); 359 #endif /* CONFIG_PM_SLEEP */ 360 361 #ifdef CONFIG_PM_TRACE 362 int pm_trace_enabled; 363 364 static ssize_t pm_trace_show(struct kobject *kobj, struct kobj_attribute *attr, 365 char *buf) 366 { 367 return sprintf(buf, "%d\n", pm_trace_enabled); 368 } 369 370 static ssize_t 371 pm_trace_store(struct kobject *kobj, struct kobj_attribute *attr, 372 const char *buf, size_t n) 373 { 374 int val; 375 376 if (sscanf(buf, "%d", &val) == 1) { 377 pm_trace_enabled = !!val; 378 return n; 379 } 380 return -EINVAL; 381 } 382 383 power_attr(pm_trace); 384 385 static ssize_t pm_trace_dev_match_show(struct kobject *kobj, 386 struct kobj_attribute *attr, 387 char *buf) 388 { 389 return show_trace_dev_match(buf, PAGE_SIZE); 390 } 391 392 static ssize_t 393 pm_trace_dev_match_store(struct kobject *kobj, struct kobj_attribute *attr, 394 const char *buf, size_t n) 395 { 396 return -EINVAL; 397 } 398 399 power_attr(pm_trace_dev_match); 400 401 #endif /* CONFIG_PM_TRACE */ 402 403 static struct attribute * g[] = { 404 &state_attr.attr, 405 #ifdef CONFIG_PM_TRACE 406 &pm_trace_attr.attr, 407 &pm_trace_dev_match_attr.attr, 408 #endif 409 #ifdef CONFIG_PM_SLEEP 410 &pm_async_attr.attr, 411 &wakeup_count_attr.attr, 412 #ifdef CONFIG_PM_DEBUG 413 &pm_test_attr.attr, 414 #endif 415 #endif 416 NULL, 417 }; 418 419 static struct attribute_group attr_group = { 420 .attrs = g, 421 }; 422 423 #ifdef CONFIG_PM_RUNTIME 424 struct workqueue_struct *pm_wq; 425 EXPORT_SYMBOL_GPL(pm_wq); 426 427 static int __init pm_start_workqueue(void) 428 { 429 pm_wq = alloc_workqueue("pm", WQ_FREEZABLE, 0); 430 431 return pm_wq ? 0 : -ENOMEM; 432 } 433 #else 434 static inline int pm_start_workqueue(void) { return 0; } 435 #endif 436 437 static int __init pm_init(void) 438 { 439 int error = pm_start_workqueue(); 440 if (error) 441 return error; 442 hibernate_image_size_init(); 443 hibernate_reserved_size_init(); 444 power_kobj = kobject_create_and_add("power", NULL); 445 if (!power_kobj) 446 return -ENOMEM; 447 return sysfs_create_group(power_kobj, &attr_group); 448 } 449 450 core_initcall(pm_init); 451