144 lines
5.5 KiB
C
144 lines
5.5 KiB
C
/*
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ChibiOS/RT - Copyright (C) 2006,2007,2008,2009,2010 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
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/*
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* Module dependencies check.
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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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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 mb_fullsem; /**< @brief Full counter
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@p Semaphore. */
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Semaphore mb_emptysem; /**< @brief Empty counter
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@p Semaphore. */
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} Mailbox;
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#ifdef __cplusplus
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extern "C" {
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#endif
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void chMBInit(Mailbox *mbp, msg_t *buf, cnt_t n);
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void chMBReset(Mailbox *mbp);
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msg_t chMBPost(Mailbox *mbp, msg_t msg, systime_t timeout);
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msg_t chMBPostS(Mailbox *mbp, msg_t msg, systime_t timeout);
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msg_t chMBPostAhead(Mailbox *mbp, msg_t msg, systime_t timeout);
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msg_t chMBPostAheadS(Mailbox *mbp, msg_t msg, systime_t timeout);
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msg_t chMBFetch(Mailbox *mbp, msg_t *msgp, systime_t timeout);
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msg_t chMBFetchS(Mailbox *mbp, msg_t *msgp, systime_t timeout);
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#ifdef __cplusplus
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}
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#endif
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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 object
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*/
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#define chMBSize(mbp) \
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((mbp)->mb_top - (mbp)->mb_buffer)
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/**
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* @brief Returns the free space into the 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 object
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* @return The number of empty message slots.
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*/
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#define chMBGetEmpty(mbp) chSemGetCounterI(&(mbp)->mb_emptysem)
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/**
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* @brief Returns the number of messages into the 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 object
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* @return The number of queued messages.
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*/
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#define chMBGetFull(mbp) chSemGetCounterI(&(mbp)->mb_fullsem)
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/**
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* @brief Returns the next message in the queue without removing it.
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* @note A message must be waiting in the queue for this function to work or
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* it would return garbage. The correct way to use this macro is to
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* use @p chMBGetFull() and then use this macro, all within a lock
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* state.
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*/
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#define chMBPeek(mbp) (*(mbp)->mb_rdptr)
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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 name = _MAILBOX_DATA(name, buffer, size)
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#endif /* CH_USE_MAILBOXES */
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#endif /* _CHMBOXES_H_ */
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/** @} */
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