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/*
ChibiOS - Copyright (C) 2006..2018 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 nil/src/chmsg.c
* @brief Nil RTOS synchronous messages source file.
*
* @addtogroup NIL_MESSAGES
* @{
*/
#include "ch.h"
#if (CH_CFG_USE_MESSAGES == TRUE) || defined(__DOXYGEN__)
/*===========================================================================*/
/* Module local definitions. */
/*===========================================================================*/
/*===========================================================================*/
/* Module exported variables. */
/*===========================================================================*/
/*===========================================================================*/
/* Module local variables. */
/*===========================================================================*/
/*===========================================================================*/
/* Module local functions. */
/*===========================================================================*/
/*===========================================================================*/
/* Module interrupt handlers. */
/*===========================================================================*/
/*===========================================================================*/
/* Module exported functions. */
/*===========================================================================*/
/**
* @brief Sends a message to the specified thread.
* @details The sender is stopped until the receiver executes a
* @p chMsgRelease()after receiving the message.
*
* @param[in] tp the pointer to the thread
* @param[in] msg the message
* @return The answer message from @p chMsgRelease().
*
* @api
*/
msg_t chMsgSend(thread_t *tp, msg_t msg) {
thread_t *ctp = nil.current;
chDbgCheck(tp != NULL);
chSysLock();
ctp->sntmsg = msg;
ctp->u1.tp = tp;
if (NIL_THD_IS_WTMSG(tp)) {
(void) chSchReadyI(tp, (msg_t)ctp);
}
msg = chSchGoSleepTimeoutS(NIL_STATE_SNDMSGQ, TIME_INFINITE);
chSysUnlock();
return msg;
}
/**
* @brief Suspends the thread and waits for an incoming message.
* @post After receiving a message the function @p chMsgGet() must be
* called in order to retrieve the message and then @p chMsgRelease()
* must be invoked in order to acknowledge the reception and send
* the answer.
* @note If the message is a pointer then you can assume that the data
* pointed by the message is stable until you invoke @p chMsgRelease()
* because the sending thread is suspended until then.
* @note The reference counter of the sender thread is not increased, the
* returned pointer is a temporary reference.
*
* @return A pointer to the thread carrying the message.
*
* @api
*/
thread_t *chMsgWait(void) {
thread_t *tp;
chSysLock();
tp = chMsgWaitS();
chSysUnlock();
return tp;
}
/**
* @brief Suspends the thread and waits for an incoming message or a
* timeout to occur.
* @post After receiving a message the function @p chMsgGet() must be
* called in order to retrieve the message and then @p chMsgRelease()
* must be invoked in order to acknowledge the reception and send
* the answer.
* @note If the message is a pointer then you can assume that the data
* pointed by the message is stable until you invoke @p chMsgRelease()
* because the sending thread is suspended until then.
* @note The reference counter of the sender thread is not increased, the
* returned pointer is a temporary reference.
*
* @param[in] timeout 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 pointer to the thread carrying the message.
* @retval NULL if a timeout occurred.
*
* @api
*/
thread_t *chMsgWaitTimeout(sysinterval_t timeout) {
thread_t *tp;
chSysLock();
tp = chMsgWaitTimeoutS(timeout);
chSysUnlock();
return tp;
}
/**
* @brief Suspends the thread and waits for an incoming message or a
* timeout to occur.
* @post After receiving a message the function @p chMsgGet() must be
* called in order to retrieve the message and then @p chMsgRelease()
* must be invoked in order to acknowledge the reception and send
* the answer.
* @note If the message is a pointer then you can assume that the data
* pointed by the message is stable until you invoke @p chMsgRelease()
* because the sending thread is suspended until then.
* @note The reference counter of the sender thread is not increased, the
* returned pointer is a temporary reference.
*
* @param[in] timeout the number of ticks before the operation timeouts,
* the following special values are allowed:
* - @a TIME_INFINITE no timeout.
* .
* @return A pointer to the thread carrying the message.
* @retval NULL if a timeout occurred.
*
* @sclass
*/
thread_t *chMsgWaitTimeoutS(sysinterval_t timeout) {
thread_t *tp;
chDbgCheckClassS();
tp = nil_find_thread(NIL_STATE_SNDMSGQ, nil.current);
if (tp == NULL) {
msg_t msg = chSchGoSleepTimeoutS(NIL_STATE_WTMSG, timeout);
if (msg != MSG_TIMEOUT) {
return (thread_t *)msg;
}
}
return tp;
}
/**
* @brief Releases a sender thread specifying a response message.
* @pre Invoke this function only after a message has been received
* using @p chMsgWait().
*
* @param[in] tp pointer to the thread
* @param[in] msg message to be returned to the sender
*
* @api
*/
void chMsgRelease(thread_t *tp, msg_t msg) {
chSysLock();
chDbgAssert(tp->state == NIL_STATE_SNDMSGQ, "invalid state");
chMsgReleaseS(tp, msg);
chSysUnlock();
}
#endif /* CH_CFG_USE_MESSAGES == TRUE */
/** @} */
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