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| author | Giovanni Di Sirio <gdisirio@gmail.com> | 2016-02-16 09:59:21 +0000 |
|---|---|---|
| committer | Giovanni Di Sirio <gdisirio@gmail.com> | 2016-02-16 09:59:21 +0000 |
| commit | 641f2c372605cf405f0dda8536b45a78e0e5e2e2 (patch) | |
| tree | f120afff37ef959b367a6023749700d5b618beff /os/common/oslib/include/chbsem.h | |
| parent | 5e24a813bef8d7ac5ca79fe9079db0fc2d2bb8b2 (diff) | |
| download | ChibiOS-641f2c372605cf405f0dda8536b45a78e0e5e2e2.tar.gz ChibiOS-641f2c372605cf405f0dda8536b45a78e0e5e2e2.tar.bz2 ChibiOS-641f2c372605cf405f0dda8536b45a78e0e5e2e2.zip | |
Tree reorganization.
git-svn-id: svn://svn.code.sf.net/p/chibios/svn/trunk@8899 35acf78f-673a-0410-8e92-d51de3d6d3f4
Diffstat (limited to 'os/common/oslib/include/chbsem.h')
| -rw-r--r-- | os/common/oslib/include/chbsem.h | 311 |
1 files changed, 311 insertions, 0 deletions
diff --git a/os/common/oslib/include/chbsem.h b/os/common/oslib/include/chbsem.h new file mode 100644 index 000000000..ac2b37e9c --- /dev/null +++ b/os/common/oslib/include/chbsem.h @@ -0,0 +1,311 @@ +/*
+ ChibiOS - Copyright (C) 2006..2015 Giovanni Di Sirio.
+
+ This file is part of ChibiOS.
+
+ ChibiOS is free software; you can redistribute it and/or modify
+ it under the terms of the GNU General Public License as published by
+ the Free Software Foundation; either version 3 of the License, or
+ (at your option) any later version.
+
+ ChibiOS is distributed in the hope that it will be useful,
+ but WITHOUT ANY WARRANTY; without even the implied warranty of
+ MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ GNU General Public License for more details.
+
+ You should have received a copy of the GNU General Public License
+ along with this program. If not, see <http://www.gnu.org/licenses/>.
+*/
+
+/**
+ * @file chbsem.h
+ * @brief Binary semaphores structures and macros.
+ *
+ * @addtogroup binary_semaphores
+ * @details Binary semaphores related APIs and services.
+ * <h2>Operation mode</h2>
+ * Binary semaphores are implemented as a set of inline functions
+ * that use the existing counting semaphores primitives. The
+ * difference between counting and binary semaphores is that the
+ * counter of binary semaphores is not allowed to grow above the
+ * value 1. Repeated signal operation are ignored. A binary
+ * semaphore can thus have only two defined states:
+ * - <b>Taken</b>, when its counter has a value of zero or lower
+ * than zero. A negative number represent the number of threads
+ * queued on the binary semaphore.
+ * - <b>Not taken</b>, when its counter has a value of one.
+ * .
+ * Binary semaphores are different from mutexes because there is no
+ * concept of ownership, a binary semaphore can be taken by a
+ * thread and signaled by another thread or an interrupt handler,
+ * mutexes can only be taken and released by the same thread. Another
+ * difference is that binary semaphores, unlike mutexes, do not
+ * implement the priority inheritance protocol.<br>
+ * In order to use the binary semaphores APIs the
+ * @p CH_CFG_USE_SEMAPHORES option must be enabled in @p chconf.h.
+ * @{
+ */
+
+#ifndef _CHBSEM_H_
+#define _CHBSEM_H_
+
+#if (CH_CFG_USE_SEMAPHORES == TRUE) || defined(__DOXYGEN__)
+
+/*===========================================================================*/
+/* Module constants. */
+/*===========================================================================*/
+
+/*===========================================================================*/
+/* Module pre-compile time settings. */
+/*===========================================================================*/
+
+/*===========================================================================*/
+/* Derived constants and error checks. */
+/*===========================================================================*/
+
+/*===========================================================================*/
+/* Module data structures and types. */
+/*===========================================================================*/
+
+/**
+ * @extends semaphore_t
+ *
+ * @brief Binary semaphore type.
+ */
+typedef struct {
+ semaphore_t sem;
+} binary_semaphore_t;
+
+/*===========================================================================*/
+/* Module macros. */
+/*===========================================================================*/
+
+/**
+ * @brief Data part of a static semaphore initializer.
+ * @details This macro should be used when statically initializing a semaphore
+ * that is part of a bigger structure.
+ *
+ * @param[in] name the name of the semaphore variable
+ * @param[in] taken the semaphore initial state
+ */
+#define _BSEMAPHORE_DATA(name, taken) \
+ {_SEMAPHORE_DATA(name.sem, ((taken) ? 0 : 1))}
+
+/**
+ * @brief Static semaphore initializer.
+ * @details Statically initialized semaphores require no explicit
+ * initialization using @p chBSemInit().
+ *
+ * @param[in] name the name of the semaphore variable
+ * @param[in] taken the semaphore initial state
+ */
+#define BSEMAPHORE_DECL(name, taken) \
+ binary_semaphore_t name = _BSEMAPHORE_DATA(name, taken)
+
+/*===========================================================================*/
+/* External declarations. */
+/*===========================================================================*/
+
+/*===========================================================================*/
+/* Module inline functions. */
+/*===========================================================================*/
+
+/**
+ * @brief Initializes a binary semaphore.
+ *
+ * @param[out] bsp pointer to a @p binary_semaphore_t structure
+ * @param[in] taken initial state of the binary semaphore:
+ * - @a false, the initial state is not taken.
+ * - @a true, the initial state is taken.
+ * .
+ *
+ * @init
+ */
+static inline void chBSemObjectInit(binary_semaphore_t *bsp, bool taken) {
+
+ chSemObjectInit(&bsp->sem, taken ? (cnt_t)0 : (cnt_t)1);
+}
+
+/**
+ * @brief Wait operation on the binary semaphore.
+ *
+ * @param[in] bsp pointer to a @p binary_semaphore_t structure
+ * @return A message specifying how the invoking thread has been
+ * released from the semaphore.
+ * @retval MSG_OK if the binary semaphore has been successfully taken.
+ * @retval MSG_RESET if the binary semaphore has been reset using
+ * @p bsemReset().
+ *
+ * @api
+ */
+static inline msg_t chBSemWait(binary_semaphore_t *bsp) {
+
+ return chSemWait(&bsp->sem);
+}
+
+/**
+ * @brief Wait operation on the binary semaphore.
+ *
+ * @param[in] bsp pointer to a @p binary_semaphore_t structure
+ * @return A message specifying how the invoking thread has been
+ * released from the semaphore.
+ * @retval MSG_OK if the binary semaphore has been successfully taken.
+ * @retval MSG_RESET if the binary semaphore has been reset using
+ * @p bsemReset().
+ *
+ * @sclass
+ */
+static inline msg_t chBSemWaitS(binary_semaphore_t *bsp) {
+
+ chDbgCheckClassS();
+
+ return chSemWaitS(&bsp->sem);
+}
+
+/**
+ * @brief Wait operation on the binary semaphore.
+ *
+ * @param[in] bsp pointer to a @p binary_semaphore_t structure
+ * @param[in] time the number of ticks before the operation timeouts,
+ * the following special values are allowed:
+ * - @a TIME_IMMEDIATE immediate timeout.
+ * - @a TIME_INFINITE no timeout.
+ * .
+ * @return A message specifying how the invoking thread has been
+ * released from the semaphore.
+ * @retval MSG_OK if the binary semaphore has been successfully taken.
+ * @retval MSG_RESET if the binary semaphore has been reset using
+ * @p bsemReset().
+ * @retval MSG_TIMEOUT if the binary semaphore has not been signaled or reset
+ * within the specified timeout.
+ *
+ * @sclass
+ */
+static inline msg_t chBSemWaitTimeoutS(binary_semaphore_t *bsp,
+ systime_t time) {
+
+ chDbgCheckClassS();
+
+ return chSemWaitTimeoutS(&bsp->sem, time);
+}
+
+/**
+ * @brief Wait operation on the binary semaphore.
+ *
+ * @param[in] bsp pointer to a @p binary_semaphore_t structure
+ * @param[in] time the number of ticks before the operation timeouts,
+ * the following special values are allowed:
+ * - @a TIME_IMMEDIATE immediate timeout.
+ * - @a TIME_INFINITE no timeout.
+ * .
+ * @return A message specifying how the invoking thread has been
+ * released from the semaphore.
+ * @retval MSG_OK if the binary semaphore has been successfully taken.
+ * @retval MSG_RESET if the binary semaphore has been reset using
+ * @p bsemReset().
+ * @retval MSG_TIMEOUT if the binary semaphore has not been signaled or reset
+ * within the specified timeout.
+ *
+ * @api
+ */
+static inline msg_t chBSemWaitTimeout(binary_semaphore_t *bsp,
+ systime_t time) {
+
+ return chSemWaitTimeout(&bsp->sem, time);
+}
+
+/**
+ * @brief Reset operation on the binary semaphore.
+ * @note The released threads can recognize they were waked up by a reset
+ * rather than a signal because the @p bsemWait() will return
+ * @p MSG_RESET instead of @p MSG_OK.
+ * @note This function does not reschedule.
+ *
+ * @param[in] bsp pointer to a @p binary_semaphore_t structure
+ * @param[in] taken new state of the binary semaphore
+ * - @a false, the new state is not taken.
+ * - @a true, the new state is taken.
+ * .
+ *
+ * @iclass
+ */
+static inline void chBSemResetI(binary_semaphore_t *bsp, bool taken) {
+
+ chDbgCheckClassI();
+
+ chSemResetI(&bsp->sem, taken ? (cnt_t)0 : (cnt_t)1);
+}
+
+/**
+ * @brief Reset operation on the binary semaphore.
+ * @note The released threads can recognize they were waked up by a reset
+ * rather than a signal because the @p bsemWait() will return
+ * @p MSG_RESET instead of @p MSG_OK.
+ *
+ * @param[in] bsp pointer to a @p binary_semaphore_t structure
+ * @param[in] taken new state of the binary semaphore
+ * - @a false, the new state is not taken.
+ * - @a true, the new state is taken.
+ * .
+ *
+ * @api
+ */
+static inline void chBSemReset(binary_semaphore_t *bsp, bool taken) {
+
+ chSemReset(&bsp->sem, taken ? (cnt_t)0 : (cnt_t)1);
+}
+
+/**
+ * @brief Performs a signal operation on a binary semaphore.
+ * @note This function does not reschedule.
+ *
+ * @param[in] bsp pointer to a @p binary_semaphore_t structure
+ *
+ * @iclass
+ */
+static inline void chBSemSignalI(binary_semaphore_t *bsp) {
+
+ chDbgCheckClassI();
+
+ if (bsp->sem.cnt < (cnt_t)1) {
+ chSemSignalI(&bsp->sem);
+ }
+}
+
+/**
+ * @brief Performs a signal operation on a binary semaphore.
+ *
+ * @param[in] bsp pointer to a @p binary_semaphore_t structure
+ *
+ * @api
+ */
+static inline void chBSemSignal(binary_semaphore_t *bsp) {
+
+ chSysLock();
+ chBSemSignalI(bsp);
+ chSchRescheduleS();
+ chSysUnlock();
+}
+
+/**
+ * @brief Returns the binary semaphore current state.
+ *
+ * @param[in] bsp pointer to a @p binary_semaphore_t structure
+ * @return The binary semaphore current state.
+ * @retval false if the binary semaphore is not taken.
+ * @retval true if the binary semaphore is taken.
+ *
+ * @iclass
+ */
+static inline bool chBSemGetStateI(binary_semaphore_t *bsp) {
+
+ chDbgCheckClassI();
+
+ return (bsp->sem.cnt > (cnt_t)0) ? false : true;
+}
+
+#endif /* CH_CFG_USE_SEMAPHORES == TRUE */
+
+#endif /* _CHBSEM_H_ */
+
+/** @} */
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