259 lines
9.6 KiB
C
259 lines
9.6 KiB
C
|
/*
|
||
|
|
ChibiOS/RT - Copyright (C) 2006,2007,2008,2009,2010,
|
||
|
|
2011,2012,2013 Giovanni Di Sirio.
|
||
|
|
|
||
|
|
This file is part of ChibiOS/RT.
|
||
|
|
|
||
|
|
ChibiOS/RT 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/RT 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/>.
|
||
|
|
|
||
|
|
---
|
||
|
|
|
||
|
|
A special exception to the GPL can be applied should you wish to distribute
|
||
|
|
a combined work that includes ChibiOS/RT, without being obliged to provide
|
||
|
|
the source code for any proprietary components. See the file exception.txt
|
||
|
|
for full details of how and when the exception can be applied.
|
||
|
|
*/
|
||
|
|
|
||
|
|
/**
|
||
|
|
* @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 macros 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
|
||
|
|
* the 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_USE_SEMAPHORES
|
||
|
|
* option must be enabled in @p chconf.h.
|
||
|
|
* @{
|
||
|
|
*/
|
||
|
|
|
||
|
|
#ifndef _CHBSEM_H_
|
||
|
|
#define _CHBSEM_H_
|
||
|
|
|
||
|
|
#if CH_USE_SEMAPHORES || defined(__DOXYGEN__)
|
||
|
|
|
||
|
|
/**
|
||
|
|
* @extends Semaphore
|
||
|
|
*
|
||
|
|
* @brief Binary semaphore type.
|
||
|
|
*/
|
||
|
|
typedef struct {
|
||
|
|
Semaphore bs_sem;
|
||
|
|
} BinarySemaphore;
|
||
|
|
|
||
|
|
/**
|
||
|
|
* @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.bs_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) \
|
||
|
|
BinarySemaphore name = _BSEMAPHORE_DATA(name, taken)
|
||
|
|
|
||
|
|
/**
|
||
|
|
* @name Macro Functions
|
||
|
|
* @{
|
||
|
|
*/
|
||
|
|
/**
|
||
|
|
* @brief Initializes a binary semaphore.
|
||
|
|
*
|
||
|
|
* @param[out] bsp pointer to a @p BinarySemaphore 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
|
||
|
|
*/
|
||
|
|
#define chBSemInit(bsp, taken) chSemInit(&(bsp)->bs_sem, (taken) ? 0 : 1)
|
||
|
|
|
||
|
|
/**
|
||
|
|
* @brief Wait operation on the binary semaphore.
|
||
|
|
*
|
||
|
|
* @param[in] bsp pointer to a @p BinarySemaphore structure
|
||
|
|
* @return A message specifying how the invoking thread has been
|
||
|
|
* released from the semaphore.
|
||
|
|
* @retval RDY_OK if the binary semaphore has been successfully taken.
|
||
|
|
* @retval RDY_RESET if the binary semaphore has been reset using
|
||
|
|
* @p bsemReset().
|
||
|
|
*
|
||
|
|
* @api
|
||
|
|
*/
|
||
|
|
#define chBSemWait(bsp) chSemWait(&(bsp)->bs_sem)
|
||
|
|
|
||
|
|
/**
|
||
|
|
* @brief Wait operation on the binary semaphore.
|
||
|
|
*
|
||
|
|
* @param[in] bsp pointer to a @p BinarySemaphore structure
|
||
|
|
* @return A message specifying how the invoking thread has been
|
||
|
|
* released from the semaphore.
|
||
|
|
* @retval RDY_OK if the binary semaphore has been successfully taken.
|
||
|
|
* @retval RDY_RESET if the binary semaphore has been reset using
|
||
|
|
* @p bsemReset().
|
||
|
|
*
|
||
|
|
* @sclass
|
||
|
|
*/
|
||
|
|
#define chBSemWaitS(bsp) chSemWaitS(&(bsp)->bs_sem)
|
||
|
|
|
||
|
|
/**
|
||
|
|
* @brief Wait operation on the binary semaphore.
|
||
|
|
*
|
||
|
|
* @param[in] bsp pointer to a @p BinarySemaphore 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 RDY_OK if the binary semaphore has been successfully taken.
|
||
|
|
* @retval RDY_RESET if the binary semaphore has been reset using
|
||
|
|
* @p bsemReset().
|
||
|
|
* @retval RDY_TIMEOUT if the binary semaphore has not been signaled or reset
|
||
|
|
* within the specified timeout.
|
||
|
|
*
|
||
|
|
* @api
|
||
|
|
*/
|
||
|
|
#define chBSemWaitTimeout(bsp, time) chSemWaitTimeout(&(bsp)->bs_sem, (time))
|
||
|
|
|
||
|
|
/**
|
||
|
|
* @brief Wait operation on the binary semaphore.
|
||
|
|
*
|
||
|
|
* @param[in] bsp pointer to a @p BinarySemaphore 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 RDY_OK if the binary semaphore has been successfully taken.
|
||
|
|
* @retval RDY_RESET if the binary semaphore has been reset using
|
||
|
|
* @p bsemReset().
|
||
|
|
* @retval RDY_TIMEOUT if the binary semaphore has not been signaled or reset
|
||
|
|
* within the specified timeout.
|
||
|
|
*
|
||
|
|
* @sclass
|
||
|
|
*/
|
||
|
|
#define chBSemWaitTimeoutS(bsp, time) chSemWaitTimeoutS(&(bsp)->bs_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 RDY_RESET instead of @p RDY_OK.
|
||
|
|
*
|
||
|
|
* @param[in] bsp pointer to a @p BinarySemaphore 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
|
||
|
|
*/
|
||
|
|
#define chBSemReset(bsp, taken) chSemReset(&(bsp)->bs_sem, (taken) ? 0 : 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 RDY_RESET instead of @p RDY_OK.
|
||
|
|
* @note This function does not reschedule.
|
||
|
|
*
|
||
|
|
* @param[in] bsp pointer to a @p BinarySemaphore 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
|
||
|
|
*/
|
||
|
|
#define chBSemResetI(bsp, taken) chSemResetI(&(bsp)->bs_sem, (taken) ? 0 : 1)
|
||
|
|
|
||
|
|
/**
|
||
|
|
* @brief Performs a signal operation on a binary semaphore.
|
||
|
|
*
|
||
|
|
* @param[in] bsp pointer to a @p BinarySemaphore structure
|
||
|
|
*
|
||
|
|
* @api
|
||
|
|
*/
|
||
|
|
#define chBSemSignal(bsp) { \
|
||
|
|
chSysLock(); \
|
||
|
|
chBSemSignalI((bsp)); \
|
||
|
|
chSchRescheduleS(); \
|
||
|
|
chSysUnlock(); \
|
||
|
|
}
|
||
|
|
|
||
|
|
/**
|
||
|
|
* @brief Performs a signal operation on a binary semaphore.
|
||
|
|
* @note This function does not reschedule.
|
||
|
|
*
|
||
|
|
* @param[in] bsp pointer to a @p BinarySemaphore structure
|
||
|
|
*
|
||
|
|
* @iclass
|
||
|
|
*/
|
||
|
|
#define chBSemSignalI(bsp) { \
|
||
|
|
if ((bsp)->bs_sem.s_cnt < 1) \
|
||
|
|
chSemSignalI(&(bsp)->bs_sem); \
|
||
|
|
}
|
||
|
|
|
||
|
|
/**
|
||
|
|
* @brief Returns the binary semaphore current state.
|
||
|
|
*
|
||
|
|
* @param[in] bsp pointer to a @p BinarySemaphore 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
|
||
|
|
*/
|
||
|
|
#define chBSemGetStateI(bsp) ((bsp)->bs_sem.s_cnt > 0 ? FALSE : TRUE)
|
||
|
|
/** @} */
|
||
|
|
|
||
|
|
#endif /* CH_USE_SEMAPHORES */
|
||
|
|
|
||
|
|
#endif /* _CHBSEM_H_ */
|
||
|
|
|
||
|
|
/** @} */
|