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 unsigned int pm_flags; 21 EXPORT_SYMBOL(pm_flags); 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 return (blocking_notifier_call_chain(&pm_chain_head, val, NULL) 44 == NOTIFY_BAD) ? -EINVAL : 0; 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 #endif /* CONFIG_PM_SLEEP */ 137 138 struct kobject *power_kobj; 139 140 /** 141 * state - control system power state. 142 * 143 * show() returns what states are supported, which is hard-coded to 144 * 'standby' (Power-On Suspend), 'mem' (Suspend-to-RAM), and 145 * 'disk' (Suspend-to-Disk). 146 * 147 * store() accepts one of those strings, translates it into the 148 * proper enumerated value, and initiates a suspend transition. 149 */ 150 static ssize_t state_show(struct kobject *kobj, struct kobj_attribute *attr, 151 char *buf) 152 { 153 char *s = buf; 154 #ifdef CONFIG_SUSPEND 155 int i; 156 157 for (i = 0; i < PM_SUSPEND_MAX; i++) { 158 if (pm_states[i] && valid_state(i)) 159 s += sprintf(s,"%s ", pm_states[i]); 160 } 161 #endif 162 #ifdef CONFIG_HIBERNATION 163 s += sprintf(s, "%s\n", "disk"); 164 #else 165 if (s != buf) 166 /* convert the last space to a newline */ 167 *(s-1) = '\n'; 168 #endif 169 return (s - buf); 170 } 171 172 static ssize_t state_store(struct kobject *kobj, struct kobj_attribute *attr, 173 const char *buf, size_t n) 174 { 175 #ifdef CONFIG_SUSPEND 176 suspend_state_t state = PM_SUSPEND_STANDBY; 177 const char * const *s; 178 #endif 179 char *p; 180 int len; 181 int error = -EINVAL; 182 183 p = memchr(buf, '\n', n); 184 len = p ? p - buf : n; 185 186 /* First, check if we are requested to hibernate */ 187 if (len == 4 && !strncmp(buf, "disk", len)) { 188 error = hibernate(); 189 goto Exit; 190 } 191 192 #ifdef CONFIG_SUSPEND 193 for (s = &pm_states[state]; state < PM_SUSPEND_MAX; s++, state++) { 194 if (*s && len == strlen(*s) && !strncmp(buf, *s, len)) 195 break; 196 } 197 if (state < PM_SUSPEND_MAX && *s) 198 error = enter_state(state); 199 #endif 200 201 Exit: 202 return error ? error : n; 203 } 204 205 power_attr(state); 206 207 #ifdef CONFIG_PM_TRACE 208 int pm_trace_enabled; 209 210 static ssize_t pm_trace_show(struct kobject *kobj, struct kobj_attribute *attr, 211 char *buf) 212 { 213 return sprintf(buf, "%d\n", pm_trace_enabled); 214 } 215 216 static ssize_t 217 pm_trace_store(struct kobject *kobj, struct kobj_attribute *attr, 218 const char *buf, size_t n) 219 { 220 int val; 221 222 if (sscanf(buf, "%d", &val) == 1) { 223 pm_trace_enabled = !!val; 224 return n; 225 } 226 return -EINVAL; 227 } 228 229 power_attr(pm_trace); 230 #endif /* CONFIG_PM_TRACE */ 231 232 static struct attribute * g[] = { 233 &state_attr.attr, 234 #ifdef CONFIG_PM_TRACE 235 &pm_trace_attr.attr, 236 #endif 237 #ifdef CONFIG_PM_SLEEP 238 &pm_async_attr.attr, 239 #ifdef CONFIG_PM_DEBUG 240 &pm_test_attr.attr, 241 #endif 242 #endif 243 NULL, 244 }; 245 246 static struct attribute_group attr_group = { 247 .attrs = g, 248 }; 249 250 #ifdef CONFIG_PM_RUNTIME 251 struct workqueue_struct *pm_wq; 252 EXPORT_SYMBOL_GPL(pm_wq); 253 254 static int __init pm_start_workqueue(void) 255 { 256 pm_wq = create_freezeable_workqueue("pm"); 257 258 return pm_wq ? 0 : -ENOMEM; 259 } 260 #else 261 static inline int pm_start_workqueue(void) { return 0; } 262 #endif 263 264 static int __init pm_init(void) 265 { 266 int error = pm_start_workqueue(); 267 if (error) 268 return error; 269 power_kobj = kobject_create_and_add("power", NULL); 270 if (!power_kobj) 271 return -ENOMEM; 272 return sysfs_create_group(power_kobj, &attr_group); 273 } 274 275 core_initcall(pm_init); 276