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