1 /* 2 * kernel/power/wakelock.c 3 * 4 * User space wakeup sources support. 5 * 6 * Copyright (C) 2012 Rafael J. Wysocki <rjw@sisk.pl> 7 * 8 * This code is based on the analogous interface allowing user space to 9 * manipulate wakelocks on Android. 10 */ 11 12 #include <linux/capability.h> 13 #include <linux/ctype.h> 14 #include <linux/device.h> 15 #include <linux/err.h> 16 #include <linux/hrtimer.h> 17 #include <linux/list.h> 18 #include <linux/rbtree.h> 19 #include <linux/slab.h> 20 #include <linux/workqueue.h> 21 22 #include "power.h" 23 24 static DEFINE_MUTEX(wakelocks_lock); 25 26 struct wakelock { 27 char *name; 28 struct rb_node node; 29 struct wakeup_source ws; 30 #ifdef CONFIG_PM_WAKELOCKS_GC 31 struct list_head lru; 32 #endif 33 }; 34 35 static struct rb_root wakelocks_tree = RB_ROOT; 36 37 ssize_t pm_show_wakelocks(char *buf, bool show_active) 38 { 39 struct rb_node *node; 40 struct wakelock *wl; 41 char *str = buf; 42 char *end = buf + PAGE_SIZE; 43 44 mutex_lock(&wakelocks_lock); 45 46 for (node = rb_first(&wakelocks_tree); node; node = rb_next(node)) { 47 wl = rb_entry(node, struct wakelock, node); 48 if (wl->ws.active == show_active) 49 str += scnprintf(str, end - str, "%s ", wl->name); 50 } 51 if (str > buf) 52 str--; 53 54 str += scnprintf(str, end - str, "\n"); 55 56 mutex_unlock(&wakelocks_lock); 57 return (str - buf); 58 } 59 60 #if CONFIG_PM_WAKELOCKS_LIMIT > 0 61 static unsigned int number_of_wakelocks; 62 63 static inline bool wakelocks_limit_exceeded(void) 64 { 65 return number_of_wakelocks > CONFIG_PM_WAKELOCKS_LIMIT; 66 } 67 68 static inline void increment_wakelocks_number(void) 69 { 70 number_of_wakelocks++; 71 } 72 73 static inline void decrement_wakelocks_number(void) 74 { 75 number_of_wakelocks--; 76 } 77 #else /* CONFIG_PM_WAKELOCKS_LIMIT = 0 */ 78 static inline bool wakelocks_limit_exceeded(void) { return false; } 79 static inline void increment_wakelocks_number(void) {} 80 static inline void decrement_wakelocks_number(void) {} 81 #endif /* CONFIG_PM_WAKELOCKS_LIMIT */ 82 83 #ifdef CONFIG_PM_WAKELOCKS_GC 84 #define WL_GC_COUNT_MAX 100 85 #define WL_GC_TIME_SEC 300 86 87 static void __wakelocks_gc(struct work_struct *work); 88 static LIST_HEAD(wakelocks_lru_list); 89 static DECLARE_WORK(wakelock_work, __wakelocks_gc); 90 static unsigned int wakelocks_gc_count; 91 92 static inline void wakelocks_lru_add(struct wakelock *wl) 93 { 94 list_add(&wl->lru, &wakelocks_lru_list); 95 } 96 97 static inline void wakelocks_lru_most_recent(struct wakelock *wl) 98 { 99 list_move(&wl->lru, &wakelocks_lru_list); 100 } 101 102 static void __wakelocks_gc(struct work_struct *work) 103 { 104 struct wakelock *wl, *aux; 105 ktime_t now; 106 107 mutex_lock(&wakelocks_lock); 108 109 now = ktime_get(); 110 list_for_each_entry_safe_reverse(wl, aux, &wakelocks_lru_list, lru) { 111 u64 idle_time_ns; 112 bool active; 113 114 spin_lock_irq(&wl->ws.lock); 115 idle_time_ns = ktime_to_ns(ktime_sub(now, wl->ws.last_time)); 116 active = wl->ws.active; 117 spin_unlock_irq(&wl->ws.lock); 118 119 if (idle_time_ns < ((u64)WL_GC_TIME_SEC * NSEC_PER_SEC)) 120 break; 121 122 if (!active) { 123 wakeup_source_remove(&wl->ws); 124 rb_erase(&wl->node, &wakelocks_tree); 125 list_del(&wl->lru); 126 kfree(wl->name); 127 kfree(wl); 128 decrement_wakelocks_number(); 129 } 130 } 131 wakelocks_gc_count = 0; 132 133 mutex_unlock(&wakelocks_lock); 134 } 135 136 static void wakelocks_gc(void) 137 { 138 if (++wakelocks_gc_count <= WL_GC_COUNT_MAX) 139 return; 140 141 schedule_work(&wakelock_work); 142 } 143 #else /* !CONFIG_PM_WAKELOCKS_GC */ 144 static inline void wakelocks_lru_add(struct wakelock *wl) {} 145 static inline void wakelocks_lru_most_recent(struct wakelock *wl) {} 146 static inline void wakelocks_gc(void) {} 147 #endif /* !CONFIG_PM_WAKELOCKS_GC */ 148 149 static struct wakelock *wakelock_lookup_add(const char *name, size_t len, 150 bool add_if_not_found) 151 { 152 struct rb_node **node = &wakelocks_tree.rb_node; 153 struct rb_node *parent = *node; 154 struct wakelock *wl; 155 156 while (*node) { 157 int diff; 158 159 parent = *node; 160 wl = rb_entry(*node, struct wakelock, node); 161 diff = strncmp(name, wl->name, len); 162 if (diff == 0) { 163 if (wl->name[len]) 164 diff = -1; 165 else 166 return wl; 167 } 168 if (diff < 0) 169 node = &(*node)->rb_left; 170 else 171 node = &(*node)->rb_right; 172 } 173 if (!add_if_not_found) 174 return ERR_PTR(-EINVAL); 175 176 if (wakelocks_limit_exceeded()) 177 return ERR_PTR(-ENOSPC); 178 179 /* Not found, we have to add a new one. */ 180 wl = kzalloc(sizeof(*wl), GFP_KERNEL); 181 if (!wl) 182 return ERR_PTR(-ENOMEM); 183 184 wl->name = kstrndup(name, len, GFP_KERNEL); 185 if (!wl->name) { 186 kfree(wl); 187 return ERR_PTR(-ENOMEM); 188 } 189 wl->ws.name = wl->name; 190 wakeup_source_add(&wl->ws); 191 rb_link_node(&wl->node, parent, node); 192 rb_insert_color(&wl->node, &wakelocks_tree); 193 wakelocks_lru_add(wl); 194 increment_wakelocks_number(); 195 return wl; 196 } 197 198 int pm_wake_lock(const char *buf) 199 { 200 const char *str = buf; 201 struct wakelock *wl; 202 u64 timeout_ns = 0; 203 size_t len; 204 int ret = 0; 205 206 if (!capable(CAP_BLOCK_SUSPEND)) 207 return -EPERM; 208 209 while (*str && !isspace(*str)) 210 str++; 211 212 len = str - buf; 213 if (!len) 214 return -EINVAL; 215 216 if (*str && *str != '\n') { 217 /* Find out if there's a valid timeout string appended. */ 218 ret = kstrtou64(skip_spaces(str), 10, &timeout_ns); 219 if (ret) 220 return -EINVAL; 221 } 222 223 mutex_lock(&wakelocks_lock); 224 225 wl = wakelock_lookup_add(buf, len, true); 226 if (IS_ERR(wl)) { 227 ret = PTR_ERR(wl); 228 goto out; 229 } 230 if (timeout_ns) { 231 u64 timeout_ms = timeout_ns + NSEC_PER_MSEC - 1; 232 233 do_div(timeout_ms, NSEC_PER_MSEC); 234 __pm_wakeup_event(&wl->ws, timeout_ms); 235 } else { 236 __pm_stay_awake(&wl->ws); 237 } 238 239 wakelocks_lru_most_recent(wl); 240 241 out: 242 mutex_unlock(&wakelocks_lock); 243 return ret; 244 } 245 246 int pm_wake_unlock(const char *buf) 247 { 248 struct wakelock *wl; 249 size_t len; 250 int ret = 0; 251 252 if (!capable(CAP_BLOCK_SUSPEND)) 253 return -EPERM; 254 255 len = strlen(buf); 256 if (!len) 257 return -EINVAL; 258 259 if (buf[len-1] == '\n') 260 len--; 261 262 if (!len) 263 return -EINVAL; 264 265 mutex_lock(&wakelocks_lock); 266 267 wl = wakelock_lookup_add(buf, len, false); 268 if (IS_ERR(wl)) { 269 ret = PTR_ERR(wl); 270 goto out; 271 } 272 __pm_relax(&wl->ws); 273 274 wakelocks_lru_most_recent(wl); 275 wakelocks_gc(); 276 277 out: 278 mutex_unlock(&wakelocks_lock); 279 return ret; 280 } 281