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