Send timeout is set to 10 ms. Without timeout PLC can be blocked by CAN driver: if CAN bus is not connected to controller CAN driver never returns and therfore PLC application halts. This is a temporary solution.
/*
This file is part of CanFestival, a library implementing CanOpen Stack.
Copyright (C): Edouard TISSERANT and Francis DUPIN
See COPYING file for copyrights details.
This library is free software; you can redistribute it and/or
modify it under the terms of the GNU Lesser General Public
License as published by the Free Software Foundation; either
version 2.1 of the License, or (at your option) any later version.
This library 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
Lesser General Public License for more details.
You should have received a copy of the GNU Lesser General Public
License along with this library; if not, write to the Free Software
Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
*/
#include <linux/spinlock.h>
#include <linux/jiffies.h>
#include <linux/timer.h>
#include <linux/errno.h>
#include "timer.h"
#include "applicfg.h"
static spinlock_t lock = SPIN_LOCK_UNLOCKED;
static struct timer_list timer;
static TIMEVAL last_time_read,
last_occured_alarm,
last_alarm_set;
void TimerInit(void)
{
/* only used in realtime apps */
}
void TimerCleanup(void)
{
/* only used in realtime apps */
}
void EnterMutex(void)
{
spin_lock (&lock);
}
void LeaveMutex(void)
{
spin_unlock (&lock);
}
void timer_notify(unsigned long data)
{
last_occured_alarm = last_alarm_set;
EnterMutex();
TimeDispatch();
LeaveMutex();
}
void StartTimerLoop(TimerCallback_t init_callback)
{
getElapsedTime();
last_alarm_set = last_time_read;
last_occured_alarm = last_alarm_set;
init_timer(&timer);
timer.function = timer_notify;
EnterMutex();
// At first, TimeDispatch will call init_callback.
SetAlarm(NULL, 0, init_callback, 0, 0);
LeaveMutex();
}
void StopTimerLoop(TimerCallback_t exitfunction)
{
EnterMutex();
del_timer (&timer);
exitfunction(NULL,0);
LeaveMutex();
}
void setTimer(TIMEVAL value)
{
if (value == TIMEVAL_MAX)
return;
last_alarm_set = last_time_read + value;
mod_timer (&timer, last_alarm_set);
}
TIMEVAL getElapsedTime(void)
{
last_time_read = jiffies;
return (long)last_time_read - (long)last_occured_alarm;
}
void CreateReceiveTask(CAN_PORT port, TASK_HANDLE *Thread, void* ReceiveLoopPtr)
{
*Thread = kthread_run(ReceiveLoopPtr, port, "canReceiveLoop");
}
void WaitReceiveTaskEnd(TASK_HANDLE *Thread)
{
/* join thread here because force_sig() does not work */
while((*Thread)->state <= 0)
{
; /* >0 means stopped */
}
}