kernel/power/wakelock.c

   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 //<20130327> <marc.huang> add wakelock dubug log
  22 int wakelock_debug = 1;
  23 #define _TAG_WAKELOCK "WAKELOCK"
  24 #define wakelock_log(fmt, ...)    do { if (wakelock_debug) pr_debug("[%s][%s]" fmt, _TAG_WAKELOCK, __func__, ##__VA_ARGS__); } while (0)
  25 #define wakelock_warn(fmt, ...)   do { if (wakelock_debug) pr_warn("[%s][%s]" fmt, _TAG_WAKELOCK, __func__, ##__VA_ARGS__); } while (0)
  26
  27 static DEFINE_MUTEX(wakelocks_lock);
  28
  29 struct wakelock {
  30         char                    *name;
  31         struct rb_node          node;
  32         struct wakeup_source    ws;
  33 #ifdef CONFIG_PM_WAKELOCKS_GC
  34         struct list_head        lru;
  35 #endif
  36 };
  37
  38 static struct rb_root wakelocks_tree = RB_ROOT;
  39
  40 ssize_t pm_show_wakelocks(char *buf, bool show_active)
  41 {
  42         struct rb_node *node;
  43         struct wakelock *wl;
  44         char *str = buf;
  45         char *end = buf + PAGE_SIZE;
  46
  47         mutex_lock(&wakelocks_lock);
  48
  49         for (node = rb_first(&wakelocks_tree); node; node = rb_next(node)) {
  50                 wl = rb_entry(node, struct wakelock, node);
  51                 if (wl->ws.active == show_active)
  52                         str += scnprintf(str, end - str, "%s ", wl->name);
  53         }
  54         if (str > buf)
  55                 str--;
  56
  57         str += scnprintf(str, end - str, "\n");
  58
  59         mutex_unlock(&wakelocks_lock);
  60         return (str - buf);
  61 }
  62
  63 #if CONFIG_PM_WAKELOCKS_LIMIT > 0
  64 static unsigned int number_of_wakelocks;
  65
  66 static inline bool wakelocks_limit_exceeded(void)
  67 {
  68         return number_of_wakelocks > CONFIG_PM_WAKELOCKS_LIMIT;
  69 }
  70
  71 static inline void increment_wakelocks_number(void)
  72 {
  73         number_of_wakelocks++;
  74 }
  75
  76 static inline void decrement_wakelocks_number(void)
  77 {
  78         number_of_wakelocks--;
  79 }
  80 #else /* CONFIG_PM_WAKELOCKS_LIMIT = 0 */
  81 static inline bool wakelocks_limit_exceeded(void) { return false; }
  82 static inline void increment_wakelocks_number(void) {}
  83 static inline void decrement_wakelocks_number(void) {}
  84 #endif /* CONFIG_PM_WAKELOCKS_LIMIT */
  85
  86 #ifdef CONFIG_PM_WAKELOCKS_GC
  87 #define WL_GC_COUNT_MAX 100
  88 #define WL_GC_TIME_SEC  300
  89
  90 static LIST_HEAD(wakelocks_lru_list);
  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(void)
 104 {
 105         struct wakelock *wl, *aux;
 106         ktime_t now;
 107
 108         if (++wakelocks_gc_count <= WL_GC_COUNT_MAX)
 109                 return;
 110
 111         now = ktime_get();
 112         list_for_each_entry_safe_reverse(wl, aux, &wakelocks_lru_list, lru) {
 113                 u64 idle_time_ns;
 114                 bool active;
 115
 116                 spin_lock_irq(&wl->ws.lock);
 117                 idle_time_ns = ktime_to_ns(ktime_sub(now, wl->ws.last_time));
 118                 active = wl->ws.active;
 119                 spin_unlock_irq(&wl->ws.lock);
 120
 121                 if (idle_time_ns < ((u64)WL_GC_TIME_SEC * NSEC_PER_SEC))
 122                         break;
 123
 124                 if (!active) {
 125                         wakeup_source_remove(&wl->ws);
 126                         rb_erase(&wl->node, &wakelocks_tree);
 127                         list_del(&wl->lru);
 128                         kfree(wl->name);
 129                         kfree(wl);
 130                         decrement_wakelocks_number();
 131                 }
 132         }
 133         wakelocks_gc_count = 0;
 134 }
 135 #else /* !CONFIG_PM_WAKELOCKS_GC */
 136 static inline void wakelocks_lru_add(struct wakelock *wl) {}
 137 static inline void wakelocks_lru_most_recent(struct wakelock *wl) {}
 138 static inline void wakelocks_gc(void) {}
 139 #endif /* !CONFIG_PM_WAKELOCKS_GC */
 140
 141 static struct wakelock *wakelock_lookup_add(const char *name, size_t len,
 142                                             bool add_if_not_found)
 143 {
 144         struct rb_node **node = &wakelocks_tree.rb_node;
 145         struct rb_node *parent = *node;
 146         struct wakelock *wl;
 147
 148         while (*node) {
 149                 int diff;
 150
 151                 parent = *node;
 152                 wl = rb_entry(*node, struct wakelock, node);
 153                 diff = strncmp(name, wl->name, len);
 154                 if (diff == 0) {
 155                         if (wl->name[len])
 156                                 diff = -1;
 157                         else
 158                                 return wl;
 159                 }
 160                 if (diff < 0)
 161                         node = &(*node)->rb_left;
 162                 else
 163                         node = &(*node)->rb_right;
 164         }
 165         if (!add_if_not_found)
 166                 return ERR_PTR(-EINVAL);
 167
 168         if (wakelocks_limit_exceeded())
 169                 return ERR_PTR(-ENOSPC);
 170
 171         /* Not found, we have to add a new one. */
 172         wl = kzalloc(sizeof(*wl), GFP_KERNEL);
 173         if (!wl)
 174                 return ERR_PTR(-ENOMEM);
 175
 176         wl->name = kstrndup(name, len, GFP_KERNEL);
 177         if (!wl->name) {
 178                 kfree(wl);
 179                 return ERR_PTR(-ENOMEM);
 180         }
 181         wl->ws.name = wl->name;
 182         wakeup_source_add(&wl->ws);
 183         rb_link_node(&wl->node, parent, node);
 184         rb_insert_color(&wl->node, &wakelocks_tree);
 185         wakelocks_lru_add(wl);
 186         increment_wakelocks_number();
 187         return wl;
 188 }
 189
 190 int pm_wake_lock(const char *buf)
 191 {
 192         const char *str = buf;
 193         struct wakelock *wl;
 194         u64 timeout_ns = 0;
 195         size_t len;
 196         int ret = 0;
 197
 198         /*
 199          * 20130429 marc.huang
 200          * remove CAP_BLOCK_SUSPEND capability check (rollback to android kernel 3.4)
 201          */
 202         //if (!capable(CAP_BLOCK_SUSPEND))
 203         //      return -EPERM;
 204
 205         while (*str && !isspace(*str))
 206                 str++;
 207
 208         len = str - buf;
 209         if (!len)
 210                 return -EINVAL;
 211
 212         if (*str && *str != '\n') {
 213                 /* Find out if there's a valid timeout string appended. */
 214                 ret = kstrtou64(skip_spaces(str), 10, &timeout_ns);
 215                 if (ret)
 216                         return -EINVAL;
 217         }
 218
 219         //<20130327> <marc.huang> add wakelock dubug log
 220         wakelock_log("%s\n", buf);
 221
 222         mutex_lock(&wakelocks_lock);
 223
 224         wl = wakelock_lookup_add(buf, len, true);
 225         if (IS_ERR(wl)) {
 226                 ret = PTR_ERR(wl);
 227                 goto out;
 228         }
 229         if (timeout_ns) {
 230                 u64 timeout_ms = timeout_ns + NSEC_PER_MSEC - 1;
 231
 232                 do_div(timeout_ms, NSEC_PER_MSEC);
 233                 __pm_wakeup_event(&wl->ws, timeout_ms);
 234         } else {
 235                 __pm_stay_awake(&wl->ws);
 236         }
 237
 238         wakelocks_lru_most_recent(wl);
 239
 240  out:
 241         mutex_unlock(&wakelocks_lock);
 242         return ret;
 243 }
 244
 245 int pm_wake_unlock(const char *buf)
 246 {
 247         struct wakelock *wl;
 248         size_t len;
 249         int ret = 0;
 250
 251         /*
 252          * 20130429 marc.huang
 253          * remove CAP_BLOCK_SUSPEND capability check (rollback to android kernel 3.4)
 254          */
 255         //if (!capable(CAP_BLOCK_SUSPEND))
 256         //      return -EPERM;
 257
 258         len = strlen(buf);
 259         if (!len)
 260                 return -EINVAL;
 261
 262         if (buf[len-1] == '\n')
 263                 len--;
 264
 265         if (!len)
 266                 return -EINVAL;
 267
 268         //<20130327> <marc.huang> add wakelock dubug log
 269         wakelock_log("%s\n", buf);
 270
 271         mutex_lock(&wakelocks_lock);
 272
 273         wl = wakelock_lookup_add(buf, len, false);
 274         if (IS_ERR(wl)) {
 275                 ret = PTR_ERR(wl);
 276                 goto out;
 277         }
 278         __pm_relax(&wl->ws);
 279
 280         wakelocks_lru_most_recent(wl);
 281         wakelocks_gc();
 282
 283  out:
 284         mutex_unlock(&wakelocks_lock);
 285         return ret;
 286 }