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/*
Copyright 2011 Jun Wako <wakojun@gmail.com>

This program 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 2 of the License, or
(at your option) any later version.

This program 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/>.
*/

#ifndef TIMER_H
#define TIMER_H 1

#include <stdint.h>

#if defined(__AVR__)
#include "avr/timer_avr.h"
#endif


#define TIMER_DIFF(a, b, max)   ((a) >= (b) ?  (a) - (b) : (max) - (b) + (a))
#define TIMER_DIFF_8(a, b)      TIMER_DIFF(a, b, UINT8_MAX)
#define TIMER_DIFF_16(a, b)     TIMER_DIFF(a, b, UINT16_MAX)
#define TIMER_DIFF_32(a, b)     TIMER_DIFF(a, b, UINT32_MAX)
#define TIMER_DIFF_RAW(a, b)    TIMER_DIFF_8(a, b)


#ifdef __cplusplus
extern "C" {
#endif

extern volatile uint32_t timer_count;


void timer_init(void);
void timer_clear(void);
uint16_t timer_read(void);
uint32_t timer_read32(void);
uint16_t timer_elapsed(uint16_t last);
uint32_t timer_elapsed32(uint32_t last);

#ifdef __cplusplus
}
#endif

#endif
cm"> 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/>. */ /** * @file chmsg.c * @brief Messages code. * * @addtogroup messages * @details Synchronous inter-thread messages APIs and services. * <h2>Operation Mode</h2> * Synchronous messages are an easy to use and fast IPC mechanism, * threads can both act as message servers and/or message clients, * the mechanism allows data to be carried in both directions. Note * that messages are not copied between the client and server threads * but just a pointer passed so the exchange is very time * efficient.<br> * Messages are scalar data types of type @p msg_t that are guaranteed * to be size compatible with data pointers. Note that on some * architectures function pointers can be larger that @p msg_t.<br> * Messages are usually processed in FIFO order but it is possible to * process them in priority order by enabling the * @p CH_USE_MESSAGES_PRIORITY option in @p chconf.h.<br> * @pre In order to use the message APIs the @p CH_USE_MESSAGES option * must be enabled in @p chconf.h. * @post Enabling messages requires 6-12 (depending on the architecture) * extra bytes in the @p Thread structure. * @{ */ #include "ch.h" #if CH_USE_MESSAGES || defined(__DOXYGEN__) #if CH_USE_MESSAGES_PRIORITY #define msg_insert(tp, qp) prio_insert(tp, qp) #else #define msg_insert(tp, qp) queue_insert(tp, qp) #endif /** * @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 *tp, msg_t msg) { Thread *ctp = currp; chDbgCheck(tp != NULL, "chMsgSend"); chSysLock(); ctp->p_msg = msg; ctp->p_u.wtobjp = &tp->p_msgqueue; msg_insert(ctp, &tp->p_msgqueue); if (tp->p_state == THD_STATE_WTMSG) chSchReadyI(tp); chSchGoSleepS(THD_STATE_SNDMSG); msg = ctp->p_u.rdymsg; chSysUnlock(); return msg; } /** * @brief Suspends the thread and waits for an incoming message. * @post After receiving a message the function @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. * * @return The message. * * @api */ msg_t chMsgWait(void) { msg_t msg; chSysLock(); if (!chMsgIsPendingI(currp)) chSchGoSleepS(THD_STATE_WTMSG); #if defined(CH_ARCHITECTURE_STM8) msg = chMsgGetI((volatile Thread *)currp); /* Temporary hack.*/ #else msg = chMsgGetI(currp); #endif chSysUnlock(); return msg; } /** * @brief Returns the next message in the queue. * @post After receiving a message the function @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. * * @return The message. * @retval 0 if the queue is empty. * * @api */ msg_t chMsgGet(void) { msg_t msg; chSysLock(); msg = chMsgIsPendingI(currp) ? chMsgGetI(currp) : (msg_t)NULL; chSysUnlock(); return msg; } /** * @brief Releases the thread waiting on top of the messages queue. * @pre Invoke this function only after a message has been received * using @p chMsgWait() or @p chMsgGet(). * * @param[in] msg the message returned to the message sender * * @api */ void chMsgRelease(msg_t msg) { chSysLock(); chDbgAssert(chMsgIsPendingI(currp), "chMsgRelease(), #1", "no message pending"); chSchWakeupS(fifo_remove(&currp->p_msgqueue), msg); chSysUnlock(); } #endif /* CH_USE_MESSAGES */ /** @} */