201 lines
7.7 KiB
C
201 lines
7.7 KiB
C
/*
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ChibiOS/RT - Copyright (C) 2006,2007,2008,2009,2010,
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2011,2012,2013 Giovanni Di Sirio.
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This file is part of ChibiOS/RT.
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ChibiOS/RT is free software; you can redistribute it and/or modify
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it under the terms of the GNU General Public License as published by
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the Free Software Foundation; either version 3 of the License, or
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(at your option) any later version.
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ChibiOS/RT is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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GNU General Public License for more details.
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You should have received a copy of the GNU General Public License
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along with this program. If not, see <http://www.gnu.org/licenses/>.
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*/
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/**
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* @file chmboxes.h
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* @brief Mailboxes macros and structures.
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*
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* @addtogroup mailboxes
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* @{
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*/
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#ifndef _CHMBOXES_H_
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#define _CHMBOXES_H_
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#if CH_USE_MAILBOXES || defined(__DOXYGEN__)
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/*===========================================================================*/
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/* Module constants. */
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/*===========================================================================*/
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/*===========================================================================*/
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/* Module pre-compile time settings. */
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/*===========================================================================*/
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/*===========================================================================*/
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/* Derived constants and error checks. */
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/*===========================================================================*/
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#if !CH_USE_SEMAPHORES
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#error "CH_USE_MAILBOXES requires CH_USE_SEMAPHORES"
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#endif
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/*===========================================================================*/
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/* Module data structures and types. */
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/*===========================================================================*/
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/**
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* @brief Structure representing a mailbox object.
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*/
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typedef struct {
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msg_t *mb_buffer; /**< @brief Pointer to the mailbox
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buffer. */
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msg_t *mb_top; /**< @brief Pointer to the location
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after the buffer. */
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msg_t *mb_wrptr; /**< @brief Write pointer. */
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msg_t *mb_rdptr; /**< @brief Read pointer. */
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semaphore_t mb_fullsem; /**< @brief Full counter
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@p semaphore_t. */
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semaphore_t mb_emptysem; /**< @brief Empty counter
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@p semaphore_t. */
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} mailbox_t;
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/*===========================================================================*/
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/* Module macros. */
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/*===========================================================================*/
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/**
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* @brief Data part of a static mailbox initializer.
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* @details This macro should be used when statically initializing a
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* mailbox that is part of a bigger structure.
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*
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* @param[in] name the name of the mailbox variable
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* @param[in] buffer pointer to the mailbox buffer area
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* @param[in] size size of the mailbox buffer area
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*/
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#define _MAILBOX_DATA(name, buffer, size) { \
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(msg_t *)(buffer), \
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(msg_t *)(buffer) + size, \
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(msg_t *)(buffer), \
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(msg_t *)(buffer), \
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_SEMAPHORE_DATA(name.mb_fullsem, 0), \
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_SEMAPHORE_DATA(name.mb_emptysem, size), \
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}
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/**
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* @brief Static mailbox initializer.
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* @details Statically initialized mailboxes require no explicit
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* initialization using @p chMBInit().
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*
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* @param[in] name the name of the mailbox variable
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* @param[in] buffer pointer to the mailbox buffer area
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* @param[in] size size of the mailbox buffer area
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*/
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#define MAILBOX_DECL(name, buffer, size) \
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mailbox_t name = _MAILBOX_DATA(name, buffer, size)
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/*===========================================================================*/
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/* External declarations. */
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/*===========================================================================*/
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#ifdef __cplusplus
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extern "C" {
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#endif
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void chMBInit(mailbox_t *mbp, msg_t *buf, cnt_t n);
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void chMBReset(mailbox_t *mbp);
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msg_t chMBPost(mailbox_t *mbp, msg_t msg, systime_t timeout);
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msg_t chMBPostS(mailbox_t *mbp, msg_t msg, systime_t timeout);
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msg_t chMBPostI(mailbox_t *mbp, msg_t msg);
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msg_t chMBPostAhead(mailbox_t *mbp, msg_t msg, systime_t timeout);
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msg_t chMBPostAheadS(mailbox_t *mbp, msg_t msg, systime_t timeout);
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msg_t chMBPostAheadI(mailbox_t *mbp, msg_t msg);
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msg_t chMBFetch(mailbox_t *mbp, msg_t *msgp, systime_t timeout);
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msg_t chMBFetchS(mailbox_t *mbp, msg_t *msgp, systime_t timeout);
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msg_t chMBFetchI(mailbox_t *mbp, msg_t *msgp);
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#ifdef __cplusplus
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}
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#endif
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/*===========================================================================*/
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/* Module inline functions. */
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/*===========================================================================*/
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/**
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* @brief Returns the mailbox buffer size.
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*
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* @param[in] mbp the pointer to an initialized mailbox_t object
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*
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* @iclass
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*/
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static inline size_t chMBSizeI(mailbox_t *mbp) {
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return (size_t)(mbp->mb_top - mbp->mb_buffer);
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}
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/**
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* @brief Returns the number of free message slots into a mailbox.
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* @note Can be invoked in any system state but if invoked out of a locked
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* state then the returned value may change after reading.
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* @note The returned value can be less than zero when there are waiting
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* threads on the internal semaphore.
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*
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* @param[in] mbp the pointer to an initialized mailbox_t object
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* @return The number of empty message slots.
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*
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* @iclass
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*/
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static inline cnt_t chMBGetFreeCountI(mailbox_t *mbp) {
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chDbgCheckClassI();
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return chSemGetCounterI(&mbp->mb_emptysem);
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}
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/**
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* @brief Returns the number of used message slots into a mailbox.
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* @note Can be invoked in any system state but if invoked out of a locked
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* state then the returned value may change after reading.
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* @note The returned value can be less than zero when there are waiting
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* threads on the internal semaphore.
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*
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* @param[in] mbp the pointer to an initialized mailbox_t object
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* @return The number of queued messages.
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*
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* @iclass
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*/
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static inline cnt_t chMBGetUsedCountI(mailbox_t *mbp) {
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chDbgCheckClassI();
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return chSemGetCounterI(&mbp->mb_fullsem);
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}
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/**
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* @brief Returns the next message in the queue without removing it.
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* @pre A message must be waiting in the queue for this function to work
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* or it would return garbage. The correct way to use this macro is
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* to use @p chMBGetFullCountI() and then use this macro, all within
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* a lock state.
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*
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* @iclass
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*/
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static inline cnt_t chMBPeekI(mailbox_t *mbp) {
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chDbgCheckClassI();
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return *mbp->mb_rdptr;
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}
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#endif /* CH_USE_MAILBOXES */
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#endif /* _CHMBOXES_H_ */
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/** @} */
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