1 // SPDX-License-Identifier: GPL-2.0 2 /* 3 * kernel/power/wakelock.c 4 * 5 * User space wakeup sources support. 6 * 7 * Copyright (C) 2012 Rafael J. Wysocki <rjw@sisk.pl> 8 * 9 * This code is based on the analogous interface allowing user space to 10 * manipulate wakelocks on Android. 11 */ 12 13 #include <linux/capability.h> 14 #include <linux/ctype.h> 15 #include <linux/device.h> 16 #include <linux/err.h> 17 #include <linux/hrtimer.h> 18 #include <linux/list.h> 19 #include <linux/rbtree.h> 20 #include <linux/slab.h> 21 #include <linux/workqueue.h> 22 23 #include "power.h" 24 25 static DEFINE_MUTEX(wakelocks_lock); 26 27 struct wakelock { 28 char *name; 29 struct rb_node node; 30 struct wakeup_source *ws; 31 #ifdef CONFIG_PM_WAKELOCKS_GC 32 struct list_head lru; 33 #endif 34 }; 35 36 static struct rb_root wakelocks_tree = RB_ROOT; 37 38 ssize_t pm_show_wakelocks(char *buf, bool show_active) 39 { 40 struct rb_node *node; 41 struct wakelock *wl; 42 int len = 0; 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 len += sysfs_emit_at(buf, len, "%s ", wl->name); 50 } 51 52 len += sysfs_emit_at(buf, len, "\n"); 53 54 mutex_unlock(&wakelocks_lock); 55 return len; 56 } 57 58 #if CONFIG_PM_WAKELOCKS_LIMIT > 0 59 static unsigned int number_of_wakelocks; 60 61 static inline bool wakelocks_limit_exceeded(void) 62 { 63 return number_of_wakelocks > CONFIG_PM_WAKELOCKS_LIMIT; 64 } 65 66 static inline void increment_wakelocks_number(void) 67 { 68 number_of_wakelocks++; 69 } 70 71 static inline void decrement_wakelocks_number(void) 72 { 73 number_of_wakelocks--; 74 } 75 #else /* CONFIG_PM_WAKELOCKS_LIMIT = 0 */ 76 static inline bool wakelocks_limit_exceeded(void) { return false; } 77 static inline void increment_wakelocks_number(void) {} 78 static inline void decrement_wakelocks_number(void) {} 79 #endif /* CONFIG_PM_WAKELOCKS_LIMIT */ 80 81 #ifdef CONFIG_PM_WAKELOCKS_GC 82 #define WL_GC_COUNT_MAX 100 83 #define WL_GC_TIME_SEC 300 84 85 static void __wakelocks_gc(struct work_struct *work); 86 static LIST_HEAD(wakelocks_lru_list); 87 static DECLARE_WORK(wakelock_work, __wakelocks_gc); 88 static unsigned int wakelocks_gc_count; 89 90 static inline void wakelocks_lru_add(struct wakelock *wl) 91 { 92 list_add(&wl->lru, &wakelocks_lru_list); 93 } 94 95 static inline void wakelocks_lru_most_recent(struct wakelock *wl) 96 { 97 list_move(&wl->lru, &wakelocks_lru_list); 98 } 99 100 static void __wakelocks_gc(struct work_struct *work) 101 { 102 struct wakelock *wl, *aux; 103 ktime_t now; 104 105 mutex_lock(&wakelocks_lock); 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_unregister(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 mutex_unlock(&wakelocks_lock); 132 } 133 134 static void wakelocks_gc(void) 135 { 136 if (++wakelocks_gc_count <= WL_GC_COUNT_MAX) 137 return; 138 139 schedule_work(&wakelock_work); 140 } 141 #else /* !CONFIG_PM_WAKELOCKS_GC */ 142 static inline void wakelocks_lru_add(struct wakelock *wl) {} 143 static inline void wakelocks_lru_most_recent(struct wakelock *wl) {} 144 static inline void wakelocks_gc(void) {} 145 #endif /* !CONFIG_PM_WAKELOCKS_GC */ 146 147 static struct wakelock *wakelock_lookup_add(const char *name, size_t len, 148 bool add_if_not_found) 149 { 150 struct rb_node **node = &wakelocks_tree.rb_node; 151 struct rb_node *parent = *node; 152 struct wakelock *wl; 153 154 while (*node) { 155 int diff; 156 157 parent = *node; 158 wl = rb_entry(*node, struct wakelock, node); 159 diff = strncmp(name, wl->name, len); 160 if (diff == 0) { 161 if (wl->name[len]) 162 diff = -1; 163 else 164 return wl; 165 } 166 if (diff < 0) 167 node = &(*node)->rb_left; 168 else 169 node = &(*node)->rb_right; 170 } 171 if (!add_if_not_found) 172 return ERR_PTR(-EINVAL); 173 174 if (wakelocks_limit_exceeded()) 175 return ERR_PTR(-ENOSPC); 176 177 /* Not found, we have to add a new one. */ 178 wl = kzalloc(sizeof(*wl), GFP_KERNEL); 179 if (!wl) 180 return ERR_PTR(-ENOMEM); 181 182 wl->name = kstrndup(name, len, GFP_KERNEL); 183 if (!wl->name) { 184 kfree(wl); 185 return ERR_PTR(-ENOMEM); 186 } 187 188 wl->ws = wakeup_source_register(NULL, wl->name); 189 if (!wl->ws) { 190 kfree(wl->name); 191 kfree(wl); 192 return ERR_PTR(-ENOMEM); 193 } 194 wl->ws->last_time = ktime_get(); 195 196 rb_link_node(&wl->node, parent, node); 197 rb_insert_color(&wl->node, &wakelocks_tree); 198 wakelocks_lru_add(wl); 199 increment_wakelocks_number(); 200 return wl; 201 } 202 203 int pm_wake_lock(const char *buf) 204 { 205 const char *str = buf; 206 struct wakelock *wl; 207 u64 timeout_ns = 0; 208 size_t len; 209 int ret = 0; 210 211 if (!capable(CAP_BLOCK_SUSPEND)) 212 return -EPERM; 213 214 while (*str && !isspace(*str)) 215 str++; 216 217 len = str - buf; 218 if (!len) 219 return -EINVAL; 220 221 if (*str && *str != '\n') { 222 /* Find out if there's a valid timeout string appended. */ 223 ret = kstrtou64(skip_spaces(str), 10, &timeout_ns); 224 if (ret) 225 return -EINVAL; 226 } 227 228 mutex_lock(&wakelocks_lock); 229 230 wl = wakelock_lookup_add(buf, len, true); 231 if (IS_ERR(wl)) { 232 ret = PTR_ERR(wl); 233 goto out; 234 } 235 if (timeout_ns) { 236 u64 timeout_ms = timeout_ns + NSEC_PER_MSEC - 1; 237 238 do_div(timeout_ms, NSEC_PER_MSEC); 239 __pm_wakeup_event(wl->ws, timeout_ms); 240 } else { 241 __pm_stay_awake(wl->ws); 242 } 243 244 wakelocks_lru_most_recent(wl); 245 246 out: 247 mutex_unlock(&wakelocks_lock); 248 return ret; 249 } 250 251 int pm_wake_unlock(const char *buf) 252 { 253 struct wakelock *wl; 254 size_t len; 255 int ret = 0; 256 257 if (!capable(CAP_BLOCK_SUSPEND)) 258 return -EPERM; 259 260 len = strlen(buf); 261 if (!len) 262 return -EINVAL; 263 264 if (buf[len-1] == '\n') 265 len--; 266 267 if (!len) 268 return -EINVAL; 269 270 mutex_lock(&wakelocks_lock); 271 272 wl = wakelock_lookup_add(buf, len, false); 273 if (IS_ERR(wl)) { 274 ret = PTR_ERR(wl); 275 goto out; 276 } 277 __pm_relax(wl->ws); 278 279 wakelocks_lru_most_recent(wl); 280 wakelocks_gc(); 281 282 out: 283 mutex_unlock(&wakelocks_lock); 284 return ret; 285 } 286