Travis Geiselbrecht | 1d0df69 | 2008-09-01 02:26:09 -0700 | [diff] [blame] | 1 | /* |
Travis Geiselbrecht | 671cb79 | 2009-06-28 11:27:48 -0700 | [diff] [blame] | 2 | * Copyright (c) 2008-2009 Travis Geiselbrecht |
Travis Geiselbrecht | 1d0df69 | 2008-09-01 02:26:09 -0700 | [diff] [blame] | 3 | * |
| 4 | * Permission is hereby granted, free of charge, to any person obtaining |
| 5 | * a copy of this software and associated documentation files |
| 6 | * (the "Software"), to deal in the Software without restriction, |
| 7 | * including without limitation the rights to use, copy, modify, merge, |
| 8 | * publish, distribute, sublicense, and/or sell copies of the Software, |
| 9 | * and to permit persons to whom the Software is furnished to do so, |
| 10 | * subject to the following conditions: |
| 11 | * |
| 12 | * The above copyright notice and this permission notice shall be |
| 13 | * included in all copies or substantial portions of the Software. |
| 14 | * |
| 15 | * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, |
| 16 | * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF |
| 17 | * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. |
| 18 | * IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY |
| 19 | * CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, |
| 20 | * TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE |
| 21 | * SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE. |
| 22 | */ |
Travis Geiselbrecht | 12403e3 | 2010-05-06 13:36:57 -0700 | [diff] [blame] | 23 | |
| 24 | /** |
| 25 | * @file |
| 26 | * @brief Event wait and signal functions for threads. |
| 27 | * @defgroup event Events |
| 28 | * |
| 29 | * An event is a subclass of a wait queue. |
| 30 | * |
| 31 | * Threads wait for events, with optional timeouts. |
| 32 | * |
| 33 | * Events are "signaled", releasing waiting threads to continue. |
| 34 | * Signals may be one-shot signals (EVENT_FLAG_AUTOUNSIGNAL), in which |
| 35 | * case one signal releases only one thread, at which point it is |
| 36 | * automatically cleared. Otherwise, signals release all waiting threads |
| 37 | * to continue immediately until the signal is manually cleared with |
| 38 | * event_unsignal(). |
| 39 | * |
| 40 | * @{ |
| 41 | */ |
| 42 | |
Travis Geiselbrecht | 1d0df69 | 2008-09-01 02:26:09 -0700 | [diff] [blame] | 43 | #include <debug.h> |
| 44 | #include <err.h> |
| 45 | #include <kernel/event.h> |
| 46 | |
| 47 | #if DEBUGLEVEL > 1 |
| 48 | #define EVENT_CHECK 1 |
| 49 | #endif |
| 50 | |
Travis Geiselbrecht | 12403e3 | 2010-05-06 13:36:57 -0700 | [diff] [blame] | 51 | /** |
| 52 | * @brief Initialize an event object |
| 53 | * |
| 54 | * @param e Event object to initialize |
| 55 | * @param initial Initial value for "signaled" state |
| 56 | * @param flags 0 or EVENT_FLAG_AUTOUNSIGNAL |
| 57 | */ |
Travis Geiselbrecht | 1d0df69 | 2008-09-01 02:26:09 -0700 | [diff] [blame] | 58 | void event_init(event_t *e, bool initial, uint flags) |
| 59 | { |
| 60 | #if EVENT_CHECK |
| 61 | // ASSERT(e->magic != EVENT_MAGIC); |
| 62 | #endif |
| 63 | |
| 64 | e->magic = EVENT_MAGIC; |
| 65 | e->signalled = initial; |
| 66 | e->flags = flags; |
| 67 | wait_queue_init(&e->wait); |
| 68 | } |
| 69 | |
Travis Geiselbrecht | 12403e3 | 2010-05-06 13:36:57 -0700 | [diff] [blame] | 70 | /** |
| 71 | * @brief Destroy an event object. |
| 72 | * |
| 73 | * Event's resources are freed and it may no longer be |
| 74 | * used until event_init() is called again. Any threads |
| 75 | * still waiting on the event will be resumed. |
| 76 | * |
| 77 | * @param e Event object to initialize |
| 78 | */ |
Travis Geiselbrecht | 1d0df69 | 2008-09-01 02:26:09 -0700 | [diff] [blame] | 79 | void event_destroy(event_t *e) |
| 80 | { |
| 81 | enter_critical_section(); |
| 82 | |
| 83 | #if EVENT_CHECK |
| 84 | ASSERT(e->magic == EVENT_MAGIC); |
| 85 | #endif |
| 86 | |
| 87 | e->magic = 0; |
| 88 | e->signalled = false; |
| 89 | e->flags = 0; |
| 90 | wait_queue_destroy(&e->wait, true); |
| 91 | |
| 92 | exit_critical_section(); |
| 93 | } |
| 94 | |
Travis Geiselbrecht | 12403e3 | 2010-05-06 13:36:57 -0700 | [diff] [blame] | 95 | /** |
| 96 | * @brief Wait for event to be signaled |
| 97 | * |
| 98 | * If the event has already been signaled, this function |
| 99 | * returns immediately. Otherwise, the current thread |
| 100 | * goes to sleep until the event object is signaled, |
| 101 | * the timeout is reached, or the event object is destroyed |
| 102 | * by another thread. |
| 103 | * |
| 104 | * @param e Event object |
| 105 | * @param timeout Timeout value, in ms |
| 106 | * |
| 107 | * @return 0 on success, ERR_TIMED_OUT on timeout, |
| 108 | * other values on other errors. |
| 109 | */ |
Travis Geiselbrecht | 1d0df69 | 2008-09-01 02:26:09 -0700 | [diff] [blame] | 110 | status_t event_wait_timeout(event_t *e, time_t timeout) |
| 111 | { |
| 112 | status_t ret = NO_ERROR; |
| 113 | |
| 114 | enter_critical_section(); |
| 115 | |
| 116 | #if EVENT_CHECK |
| 117 | ASSERT(e->magic == EVENT_MAGIC); |
| 118 | #endif |
| 119 | |
| 120 | if (e->signalled) { |
| 121 | /* signalled, we're going to fall through */ |
| 122 | if (e->flags & EVENT_FLAG_AUTOUNSIGNAL) { |
| 123 | /* autounsignal flag lets one thread fall through before unsignalling */ |
| 124 | e->signalled = false; |
| 125 | } |
| 126 | } else { |
| 127 | /* unsignalled, block here */ |
| 128 | ret = wait_queue_block(&e->wait, timeout); |
| 129 | if (ret < 0) |
| 130 | goto err; |
| 131 | } |
| 132 | |
| 133 | err: |
| 134 | exit_critical_section(); |
| 135 | |
| 136 | return ret; |
| 137 | } |
| 138 | |
Travis Geiselbrecht | 12403e3 | 2010-05-06 13:36:57 -0700 | [diff] [blame] | 139 | /** |
| 140 | * @brief Same as event_wait_timeout(), but without a timeout. |
| 141 | */ |
Travis Geiselbrecht | 1d0df69 | 2008-09-01 02:26:09 -0700 | [diff] [blame] | 142 | status_t event_wait(event_t *e) |
| 143 | { |
| 144 | return event_wait_timeout(e, INFINITE_TIME); |
| 145 | } |
| 146 | |
Travis Geiselbrecht | 12403e3 | 2010-05-06 13:36:57 -0700 | [diff] [blame] | 147 | /** |
| 148 | * @brief Signal an event |
| 149 | * |
| 150 | * Signals an event. If EVENT_FLAG_AUTOUNSIGNAL is set in the event |
| 151 | * object's flags, only one waiting thread is allowed to proceed. Otherwise, |
| 152 | * all waiting threads are allowed to proceed until such time as |
| 153 | * event_unsignal() is called. |
| 154 | * |
| 155 | * @param e Event object |
| 156 | * @param reschedule If true, waiting thread(s) are executed immediately, |
| 157 | * and the current thread resumes only after the |
| 158 | * waiting threads have been satisfied. If false, |
| 159 | * waiting threads are placed at the end of the run |
| 160 | * queue. |
| 161 | * |
| 162 | * @return Returns NO_ERROR on success. |
| 163 | */ |
Travis Geiselbrecht | 1d0df69 | 2008-09-01 02:26:09 -0700 | [diff] [blame] | 164 | status_t event_signal(event_t *e, bool reschedule) |
| 165 | { |
| 166 | enter_critical_section(); |
| 167 | |
| 168 | #if EVENT_CHECK |
| 169 | ASSERT(e->magic == EVENT_MAGIC); |
| 170 | #endif |
| 171 | |
| 172 | if (!e->signalled) { |
Travis Geiselbrecht | 1d0df69 | 2008-09-01 02:26:09 -0700 | [diff] [blame] | 173 | if (e->flags & EVENT_FLAG_AUTOUNSIGNAL) { |
Travis Geiselbrecht | bb777a1 | 2009-01-20 00:24:27 -0800 | [diff] [blame] | 174 | /* try to release one thread and leave unsignalled if successful */ |
| 175 | if (wait_queue_wake_one(&e->wait, reschedule, NO_ERROR) <= 0) { |
| 176 | /* |
| 177 | * if we didn't actually find a thread to wake up, go to |
| 178 | * signalled state and let the next call to event_wait |
| 179 | * unsignal the event. |
| 180 | */ |
| 181 | e->signalled = true; |
| 182 | } |
Travis Geiselbrecht | 1d0df69 | 2008-09-01 02:26:09 -0700 | [diff] [blame] | 183 | } else { |
travis geiselbrecht | d98cea1 | 2008-09-18 16:01:03 +0000 | [diff] [blame] | 184 | /* release all threads and remain signalled */ |
Travis Geiselbrecht | bb777a1 | 2009-01-20 00:24:27 -0800 | [diff] [blame] | 185 | e->signalled = true; |
Travis Geiselbrecht | 1d0df69 | 2008-09-01 02:26:09 -0700 | [diff] [blame] | 186 | wait_queue_wake_all(&e->wait, reschedule, NO_ERROR); |
| 187 | } |
| 188 | } |
| 189 | |
| 190 | exit_critical_section(); |
| 191 | |
| 192 | return NO_ERROR; |
| 193 | } |
| 194 | |
Travis Geiselbrecht | 12403e3 | 2010-05-06 13:36:57 -0700 | [diff] [blame] | 195 | /** |
| 196 | * @brief Clear the "signaled" property of an event |
| 197 | * |
| 198 | * Used mainly for event objects without the EVENT_FLAG_AUTOUNSIGNAL |
| 199 | * flag. Once this function is called, threads that call event_wait() |
| 200 | * functions will once again need to wait until the event object |
| 201 | * is signaled. |
| 202 | * |
| 203 | * @param e Event object |
| 204 | * |
| 205 | * @return Returns NO_ERROR on success. |
| 206 | */ |
Travis Geiselbrecht | 1d0df69 | 2008-09-01 02:26:09 -0700 | [diff] [blame] | 207 | status_t event_unsignal(event_t *e) |
| 208 | { |
| 209 | enter_critical_section(); |
| 210 | |
| 211 | #if EVENT_CHECK |
| 212 | ASSERT(e->magic == EVENT_MAGIC); |
| 213 | #endif |
| 214 | |
| 215 | e->signalled = false; |
| 216 | |
| 217 | exit_critical_section(); |
| 218 | |
| 219 | return NO_ERROR; |
| 220 | } |
| 221 | |