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 #ifdef CONFIG_PM_DEBUG 48 int pm_test_level = TEST_NONE; 49 50 static const char * const pm_tests[__TEST_AFTER_LAST] = { 51 [TEST_NONE] = "none", 52 [TEST_CORE] = "core", 53 [TEST_CPUS] = "processors", 54 [TEST_PLATFORM] = "platform", 55 [TEST_DEVICES] = "devices", 56 [TEST_FREEZER] = "freezer", 57 }; 58 59 static ssize_t pm_test_show(struct kobject *kobj, struct kobj_attribute *attr, 60 char *buf) 61 { 62 char *s = buf; 63 int level; 64 65 for (level = TEST_FIRST; level <= TEST_MAX; level++) 66 if (pm_tests[level]) { 67 if (level == pm_test_level) 68 s += sprintf(s, "[%s] ", pm_tests[level]); 69 else 70 s += sprintf(s, "%s ", pm_tests[level]); 71 } 72 73 if (s != buf) 74 /* convert the last space to a newline */ 75 *(s-1) = '\n'; 76 77 return (s - buf); 78 } 79 80 static ssize_t pm_test_store(struct kobject *kobj, struct kobj_attribute *attr, 81 const char *buf, size_t n) 82 { 83 const char * const *s; 84 int level; 85 char *p; 86 int len; 87 int error = -EINVAL; 88 89 p = memchr(buf, '\n', n); 90 len = p ? p - buf : n; 91 92 mutex_lock(&pm_mutex); 93 94 level = TEST_FIRST; 95 for (s = &pm_tests[level]; level <= TEST_MAX; s++, level++) 96 if (*s && len == strlen(*s) && !strncmp(buf, *s, len)) { 97 pm_test_level = level; 98 error = 0; 99 break; 100 } 101 102 mutex_unlock(&pm_mutex); 103 104 return error ? error : n; 105 } 106 107 power_attr(pm_test); 108 #endif /* CONFIG_PM_DEBUG */ 109 110 #endif /* CONFIG_PM_SLEEP */ 111 112 struct kobject *power_kobj; 113 114 /** 115 * state - control system power state. 116 * 117 * show() returns what states are supported, which is hard-coded to 118 * 'standby' (Power-On Suspend), 'mem' (Suspend-to-RAM), and 119 * 'disk' (Suspend-to-Disk). 120 * 121 * store() accepts one of those strings, translates it into the 122 * proper enumerated value, and initiates a suspend transition. 123 */ 124 static ssize_t state_show(struct kobject *kobj, struct kobj_attribute *attr, 125 char *buf) 126 { 127 char *s = buf; 128 #ifdef CONFIG_SUSPEND 129 int i; 130 131 for (i = 0; i < PM_SUSPEND_MAX; i++) { 132 if (pm_states[i] && valid_state(i)) 133 s += sprintf(s,"%s ", pm_states[i]); 134 } 135 #endif 136 #ifdef CONFIG_HIBERNATION 137 s += sprintf(s, "%s\n", "disk"); 138 #else 139 if (s != buf) 140 /* convert the last space to a newline */ 141 *(s-1) = '\n'; 142 #endif 143 return (s - buf); 144 } 145 146 static ssize_t state_store(struct kobject *kobj, struct kobj_attribute *attr, 147 const char *buf, size_t n) 148 { 149 #ifdef CONFIG_SUSPEND 150 suspend_state_t state = PM_SUSPEND_STANDBY; 151 const char * const *s; 152 #endif 153 char *p; 154 int len; 155 int error = -EINVAL; 156 157 p = memchr(buf, '\n', n); 158 len = p ? p - buf : n; 159 160 /* First, check if we are requested to hibernate */ 161 if (len == 4 && !strncmp(buf, "disk", len)) { 162 error = hibernate(); 163 goto Exit; 164 } 165 166 #ifdef CONFIG_SUSPEND 167 for (s = &pm_states[state]; state < PM_SUSPEND_MAX; s++, state++) { 168 if (*s && len == strlen(*s) && !strncmp(buf, *s, len)) 169 break; 170 } 171 if (state < PM_SUSPEND_MAX && *s) 172 error = enter_state(state); 173 #endif 174 175 Exit: 176 return error ? error : n; 177 } 178 179 power_attr(state); 180 181 #ifdef CONFIG_PM_TRACE 182 int pm_trace_enabled; 183 184 static ssize_t pm_trace_show(struct kobject *kobj, struct kobj_attribute *attr, 185 char *buf) 186 { 187 return sprintf(buf, "%d\n", pm_trace_enabled); 188 } 189 190 static ssize_t 191 pm_trace_store(struct kobject *kobj, struct kobj_attribute *attr, 192 const char *buf, size_t n) 193 { 194 int val; 195 196 if (sscanf(buf, "%d", &val) == 1) { 197 pm_trace_enabled = !!val; 198 return n; 199 } 200 return -EINVAL; 201 } 202 203 power_attr(pm_trace); 204 #endif /* CONFIG_PM_TRACE */ 205 206 static struct attribute * g[] = { 207 &state_attr.attr, 208 #ifdef CONFIG_PM_TRACE 209 &pm_trace_attr.attr, 210 #endif 211 #if defined(CONFIG_PM_SLEEP) && defined(CONFIG_PM_DEBUG) 212 &pm_test_attr.attr, 213 #endif 214 NULL, 215 }; 216 217 static struct attribute_group attr_group = { 218 .attrs = g, 219 }; 220 221 #ifdef CONFIG_PM_RUNTIME 222 struct workqueue_struct *pm_wq; 223 224 static int __init pm_start_workqueue(void) 225 { 226 pm_wq = create_freezeable_workqueue("pm"); 227 228 return pm_wq ? 0 : -ENOMEM; 229 } 230 #else 231 static inline int pm_start_workqueue(void) { return 0; } 232 #endif 233 234 static int __init pm_init(void) 235 { 236 int error = pm_start_workqueue(); 237 if (error) 238 return error; 239 power_kobj = kobject_create_and_add("power", NULL); 240 if (!power_kobj) 241 return -ENOMEM; 242 return sysfs_create_group(power_kobj, &attr_group); 243 } 244 245 core_initcall(pm_init); 246