can.c
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/*
ChibiOS/RT - Copyright (C) 2006,2007,2008,2009,2010,
2011,2012 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 can.c
* @brief CAN Driver code.
*
* @addtogroup CAN
* @{
*/
#include "ch.h"
#include "hal.h"
#if HAL_USE_CAN || defined(__DOXYGEN__)
/*===========================================================================*/
/* Driver local definitions. */
/*===========================================================================*/
/*===========================================================================*/
/* Driver exported variables. */
/*===========================================================================*/
/*===========================================================================*/
/* Driver local variables. */
/*===========================================================================*/
/*===========================================================================*/
/* Driver local functions. */
/*===========================================================================*/
/*===========================================================================*/
/* Driver exported functions. */
/*===========================================================================*/
/**
* @brief CAN Driver initialization.
* @note This function is implicitly invoked by @p halInit(), there is
* no need to explicitly initialize the driver.
*
* @init
*/
void canInit(void) {
can_lld_init();
}
/**
* @brief Initializes the standard part of a @p CANDriver structure.
*
* @param[out] canp pointer to the @p CANDriver object
*
* @init
*/
void canObjectInit(CANDriver *canp) {
canp->state = CAN_STOP;
canp->config = NULL;
chSemInit(&canp->txsem, 0);
chSemInit(&canp->rxsem, 0);
chEvtInit(&canp->rxfull_event);
chEvtInit(&canp->txempty_event);
chEvtInit(&canp->error_event);
canp->status = 0;
#if CAN_USE_SLEEP_MODE
chEvtInit(&canp->sleep_event);
chEvtInit(&canp->wakeup_event);
#endif /* CAN_USE_SLEEP_MODE */
}
/**
* @brief Configures and activates the CAN peripheral.
* @note Activating the CAN bus can be a slow operation this this function
* is not atomic, it waits internally for the initialization to
* complete.
*
* @param[in] canp pointer to the @p CANDriver object
* @param[in] config pointer to the @p CANConfig object. Depending on
* the implementation the value can be @p NULL.
*
* @api
*/
void canStart(CANDriver *canp, const CANConfig *config) {
chDbgCheck(canp != NULL, "canStart");
chSysLock();
chDbgAssert((canp->state == CAN_STOP) ||
(canp->state == CAN_STARTING) ||
(canp->state == CAN_READY),
"canStart(), #1", "invalid state");
while (canp->state == CAN_STARTING)
chThdSleepS(1);
if (canp->state == CAN_STOP) {
canp->config = config;
can_lld_start(canp);
canp->state = CAN_READY;
}
chSysUnlock();
}
/**
* @brief Deactivates the CAN peripheral.
*
* @param[in] canp pointer to the @p CANDriver object
*
* @api
*/
void canStop(CANDriver *canp) {
chDbgCheck(canp != NULL, "canStop");
chSysLock();
chDbgAssert((canp->state == CAN_STOP) || (canp->state == CAN_READY),
"canStop(), #1", "invalid state");
can_lld_stop(canp);
chSemResetI(&canp->rxsem, 0);
chSemResetI(&canp->txsem, 0);
chSchRescheduleS();
canp->state = CAN_STOP;
canp->status = 0;
chSysUnlock();
}
/**
* @brief Can frame transmission.
* @details The specified frame is queued for transmission, if the hardware
* queue is full then the invoking thread is queued.
* @note Trying to transmit while in sleep mode simply enqueues the thread.
*
* @param[in] canp pointer to the @p CANDriver object
* @param[in] ctfp pointer to the CAN frame to be transmitted
* @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 The operation result.
* @retval RDY_OK the frame has been queued for transmission.
* @retval RDY_TIMEOUT The operation has timed out.
* @retval RDY_RESET The driver has been stopped while waiting.
*
* @api
*/
msg_t canTransmit(CANDriver *canp, const CANTxFrame *ctfp, systime_t timeout) {
chDbgCheck((canp != NULL) && (ctfp != NULL), "canTransmit");
chSysLock();
chDbgAssert((canp->state == CAN_READY) || (canp->state == CAN_SLEEP),
"canTransmit(), #1", "invalid state");
while ((canp->state == CAN_SLEEP) || !can_lld_can_transmit(canp)) {
msg_t msg = chSemWaitTimeoutS(&canp->txsem, timeout);
if (msg != RDY_OK) {
chSysUnlock();
return msg;
}
}
can_lld_transmit(canp, ctfp);
chSysUnlock();
return RDY_OK;
}
/**
* @brief Can frame receive.
* @details The function waits until a frame is received.
* @note Trying to receive while in sleep mode simply enqueues the thread.
*
* @param[in] canp pointer to the @p CANDriver object
* @param[out] crfp pointer to the buffer where the CAN frame is copied
* @param[in] timeout the number of ticks before the operation timeouts,
* the following special values are allowed:
* - @a TIME_IMMEDIATE immediate timeout (useful in an
* event driven scenario where a thread never blocks
* for I/O).
* - @a TIME_INFINITE no timeout.
* .
* @return The operation result.
* @retval RDY_OK a frame has been received and placed in the buffer.
* @retval RDY_TIMEOUT The operation has timed out.
* @retval RDY_RESET The driver has been stopped while waiting.
*
* @api
*/
msg_t canReceive(CANDriver *canp, CANRxFrame *crfp, systime_t timeout) {
chDbgCheck((canp != NULL) && (crfp != NULL), "canReceive");
chSysLock();
chDbgAssert((canp->state == CAN_READY) || (canp->state == CAN_SLEEP),
"canReceive(), #1", "invalid state");
while ((canp->state == CAN_SLEEP) || !can_lld_can_receive(canp)) {
msg_t msg = chSemWaitTimeoutS(&canp->rxsem, timeout);
if (msg != RDY_OK) {
chSysUnlock();
return msg;
}
}
can_lld_receive(canp, crfp);
chSysUnlock();
return RDY_OK;
}
/**
* @brief Returns the current status mask and clears it.
*
* @param[in] canp pointer to the @p CANDriver object
* @return The status flags mask.
*
* @api
*/
canstatus_t canGetAndClearFlags(CANDriver *canp) {
canstatus_t status;
chSysLock();
status = canp->status;
canp->status = 0;
chSysUnlock();
return status;
}
#if CAN_USE_SLEEP_MODE || defined(__DOXYGEN__)
/**
* @brief Enters the sleep mode.
* @details This function puts the CAN driver in sleep mode and broadcasts
* the @p sleep_event event source.
* @pre In order to use this function the option @p CAN_USE_SLEEP_MODE must
* be enabled and the @p CAN_SUPPORTS_SLEEP mode must be supported
* by the low level driver.
*
* @param[in] canp pointer to the @p CANDriver object
*
* @api
*/
void canSleep(CANDriver *canp) {
chDbgCheck(canp != NULL, "canSleep");
chSysLock();
chDbgAssert((canp->state == CAN_READY) || (canp->state == CAN_SLEEP),
"canSleep(), #1", "invalid state");
if (canp->state == CAN_READY) {
can_lld_sleep(canp);
canp->state = CAN_SLEEP;
chEvtBroadcastI(&canp->sleep_event);
chSchRescheduleS();
}
chSysUnlock();
}
/**
* @brief Enforces leaving the sleep mode.
* @note The sleep mode is supposed to be usually exited automatically by
* an hardware event.
*
* @param[in] canp pointer to the @p CANDriver object
*/
void canWakeup(CANDriver *canp) {
chDbgCheck(canp != NULL, "canWakeup");
chSysLock();
chDbgAssert((canp->state == CAN_READY) || (canp->state == CAN_SLEEP),
"canWakeup(), #1", "invalid state");
if (canp->state == CAN_SLEEP) {
can_lld_wakeup(canp);
canp->state = CAN_READY;
chEvtBroadcastI(&canp->wakeup_event);
chSchRescheduleS();
}
chSysUnlock();
}
#endif /* CAN_USE_SLEEP_MODE */
#endif /* HAL_USE_CAN */
/** @} */