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 char *str = buf; 43 char *end = buf + PAGE_SIZE; 44 45 mutex_lock(&wakelocks_lock); 46 47 for (node = rb_first(&wakelocks_tree); node; node = rb_next(node)) { 48 wl = rb_entry(node, struct wakelock, node); 49 if (wl->ws->active == show_active) 50 str += scnprintf(str, end - str, "%s ", wl->name); 51 } 52 if (str > buf) 53 str--; 54 55 str += scnprintf(str, end - str, "\n"); 56 57 mutex_unlock(&wakelocks_lock); 58 return (str - buf); 59 } 60 61 #if CONFIG_PM_WAKELOCKS_LIMIT > 0 62 static unsigned int number_of_wakelocks; 63 64 static inline bool wakelocks_limit_exceeded(void) 65 { 66 return number_of_wakelocks > CONFIG_PM_WAKELOCKS_LIMIT; 67 } 68 69 static inline void increment_wakelocks_number(void) 70 { 71 number_of_wakelocks++; 72 } 73 74 static inline void decrement_wakelocks_number(void) 75 { 76 number_of_wakelocks--; 77 } 78 #else /* CONFIG_PM_WAKELOCKS_LIMIT = 0 */ 79 static inline bool wakelocks_limit_exceeded(void) { return false; } 80 static inline void increment_wakelocks_number(void) {} 81 static inline void decrement_wakelocks_number(void) {} 82 #endif /* CONFIG_PM_WAKELOCKS_LIMIT */ 83 84 #ifdef CONFIG_PM_WAKELOCKS_GC 85 #define WL_GC_COUNT_MAX 100 86 #define WL_GC_TIME_SEC 300 87 88 static void __wakelocks_gc(struct work_struct *work); 89 static LIST_HEAD(wakelocks_lru_list); 90 static DECLARE_WORK(wakelock_work, __wakelocks_gc); 91 static unsigned int wakelocks_gc_count; 92 93 static inline void wakelocks_lru_add(struct wakelock *wl) 94 { 95 list_add(&wl->lru, &wakelocks_lru_list); 96 } 97 98 static inline void wakelocks_lru_most_recent(struct wakelock *wl) 99 { 100 list_move(&wl->lru, &wakelocks_lru_list); 101 } 102 103 static void __wakelocks_gc(struct work_struct *work) 104 { 105 struct wakelock *wl, *aux; 106 ktime_t now; 107 108 mutex_lock(&wakelocks_lock); 109 110 now = ktime_get(); 111 list_for_each_entry_safe_reverse(wl, aux, &wakelocks_lru_list, lru) { 112 u64 idle_time_ns; 113 bool active; 114 115 spin_lock_irq(&wl->ws->lock); 116 idle_time_ns = ktime_to_ns(ktime_sub(now, wl->ws->last_time)); 117 active = wl->ws->active; 118 spin_unlock_irq(&wl->ws->lock); 119 120 if (idle_time_ns < ((u64)WL_GC_TIME_SEC * NSEC_PER_SEC)) 121 break; 122 123 if (!active) { 124 wakeup_source_unregister(wl->ws); 125 rb_erase(&wl->node, &wakelocks_tree); 126 list_del(&wl->lru); 127 kfree(wl->name); 128 kfree(wl); 129 decrement_wakelocks_number(); 130 } 131 } 132 wakelocks_gc_count = 0; 133 134 mutex_unlock(&wakelocks_lock); 135 } 136 137 static void wakelocks_gc(void) 138 { 139 if (++wakelocks_gc_count <= WL_GC_COUNT_MAX) 140 return; 141 142 schedule_work(&wakelock_work); 143 } 144 #else /* !CONFIG_PM_WAKELOCKS_GC */ 145 static inline void wakelocks_lru_add(struct wakelock *wl) {} 146 static inline void wakelocks_lru_most_recent(struct wakelock *wl) {} 147 static inline void wakelocks_gc(void) {} 148 #endif /* !CONFIG_PM_WAKELOCKS_GC */ 149 150 static struct wakelock *wakelock_lookup_add(const char *name, size_t len, 151 bool add_if_not_found) 152 { 153 struct rb_node **node = &wakelocks_tree.rb_node; 154 struct rb_node *parent = *node; 155 struct wakelock *wl; 156 157 while (*node) { 158 int diff; 159 160 parent = *node; 161 wl = rb_entry(*node, struct wakelock, node); 162 diff = strncmp(name, wl->name, len); 163 if (diff == 0) { 164 if (wl->name[len]) 165 diff = -1; 166 else 167 return wl; 168 } 169 if (diff < 0) 170 node = &(*node)->rb_left; 171 else 172 node = &(*node)->rb_right; 173 } 174 if (!add_if_not_found) 175 return ERR_PTR(-EINVAL); 176 177 if (wakelocks_limit_exceeded()) 178 return ERR_PTR(-ENOSPC); 179 180 /* Not found, we have to add a new one. */ 181 wl = kzalloc(sizeof(*wl), GFP_KERNEL); 182 if (!wl) 183 return ERR_PTR(-ENOMEM); 184 185 wl->name = kstrndup(name, len, GFP_KERNEL); 186 if (!wl->name) { 187 kfree(wl); 188 return ERR_PTR(-ENOMEM); 189 } 190 191 wl->ws = wakeup_source_register(NULL, wl->name); 192 if (!wl->ws) { 193 kfree(wl->name); 194 kfree(wl); 195 return ERR_PTR(-ENOMEM); 196 } 197 wl->ws->last_time = ktime_get(); 198 199 rb_link_node(&wl->node, parent, node); 200 rb_insert_color(&wl->node, &wakelocks_tree); 201 wakelocks_lru_add(wl); 202 increment_wakelocks_number(); 203 return wl; 204 } 205 206 int pm_wake_lock(const char *buf) 207 { 208 const char *str = buf; 209 struct wakelock *wl; 210 u64 timeout_ns = 0; 211 size_t len; 212 int ret = 0; 213 214 if (!capable(CAP_BLOCK_SUSPEND)) 215 return -EPERM; 216 217 while (*str && !isspace(*str)) 218 str++; 219 220 len = str - buf; 221 if (!len) 222 return -EINVAL; 223 224 if (*str && *str != '\n') { 225 /* Find out if there's a valid timeout string appended. */ 226 ret = kstrtou64(skip_spaces(str), 10, &timeout_ns); 227 if (ret) 228 return -EINVAL; 229 } 230 231 mutex_lock(&wakelocks_lock); 232 233 wl = wakelock_lookup_add(buf, len, true); 234 if (IS_ERR(wl)) { 235 ret = PTR_ERR(wl); 236 goto out; 237 } 238 if (timeout_ns) { 239 u64 timeout_ms = timeout_ns + NSEC_PER_MSEC - 1; 240 241 do_div(timeout_ms, NSEC_PER_MSEC); 242 __pm_wakeup_event(wl->ws, timeout_ms); 243 } else { 244 __pm_stay_awake(wl->ws); 245 } 246 247 wakelocks_lru_most_recent(wl); 248 249 out: 250 mutex_unlock(&wakelocks_lock); 251 return ret; 252 } 253 254 int pm_wake_unlock(const char *buf) 255 { 256 struct wakelock *wl; 257 size_t len; 258 int ret = 0; 259 260 if (!capable(CAP_BLOCK_SUSPEND)) 261 return -EPERM; 262 263 len = strlen(buf); 264 if (!len) 265 return -EINVAL; 266 267 if (buf[len-1] == '\n') 268 len--; 269 270 if (!len) 271 return -EINVAL; 272 273 mutex_lock(&wakelocks_lock); 274 275 wl = wakelock_lookup_add(buf, len, false); 276 if (IS_ERR(wl)) { 277 ret = PTR_ERR(wl); 278 goto out; 279 } 280 __pm_relax(wl->ws); 281 282 wakelocks_lru_most_recent(wl); 283 wakelocks_gc(); 284 285 out: 286 mutex_unlock(&wakelocks_lock); 287 return ret; 288 } 289