/**
*
* \brief int open(const char *pathname, int flags);
* opens the CAN device for following operations
* \param pathname device pathname, usual /dev/can?
* \param flags is one of \c O_RDONLY, \c O_WRONLY or \c O_RDWR which request
* opening the file read-only, write-only or read/write,
* respectively.
*
*
* The open call is used to "open" the device.
* Doing a first initialization according the to values in the /proc/sys/Can
* file system.
* Additional an ISR function is assigned to the IRQ.
*
* The CLK OUT pin is configured for creating the same frequency
* like the chips input frequency fclk (XTAL).
*
* If Vendor Option \a VendOpt is set to 's' the driver performs
* an hardware reset befor initializing the chip.
*
* \returns
* open return the new file descriptor,
* or -1 if an error occurred (in which case, errno is set appropriately).
*
* \par ERRORS
* the following errors can occur
* \arg \c ENXIO the file is a device special file
* and no corresponding device exists.
* \arg \c EINVAL illegal \b minor device number
* \arg \c EINVAL wrong IO-model format in /proc/sys/Can/IOmodel
* \arg \c EBUSY IRQ for hardware is not available
* \arg \c EBUSY I/O region for hardware is not available
*/
int can_open( __LDDK_OPEN_PARAM )
{
int retval = 0;
DBGin("can_open");
{
int lasterr;
unsigned int minor = iminor(inode);
if( minor > MAX_CHANNELS )
{
printk(KERN_ERR "CAN: Illegal minor number %d\n", minor);
DBGout();
return -EINVAL;
}
/* check if device is already open, should be used only by one process */
if(Can_isopen[minor] == 1) {
DBGout();
return -ENXIO;
}
if( Base[minor] == 0x00) {
/* No device available */
printk(KERN_ERR "CAN[%d]: no device available\n", minor);
DBGout();
return -ENXIO;
}
/* the following does all the board specific things
also memory remapping if necessary */
if( (lasterr = CAN_VendorInit(minor)) < 0 ){
DBGout();
return lasterr;
}
/* Access macros based in can_base[] should work now */
/* CAN_ShowStat(minor); */
/* controller_available(curr + 0x400, 4); */
Can_WaitInit(minor); /* initialize wait queue for select() */
Can_FifoInit(minor);
#if CAN_USE_FILTER
Can_FilterInit(minor);
#endif
if( CAN_ChipReset(minor) < 0 ) {
DBGout();
return -EINVAL;
}
CAN_StartChip(minor);
#if DEBUG
CAN_ShowStat(minor);
#endif
++Can_isopen[minor]; /* flag device in use */
}
DBGout();
return retval;
}
int can_select( __LDDK_SELECT_PARAM )
#endif
{
unsigned int minor = __LDDK_MINOR;
msg_fifo_t *RxFifo = &Rx_Buf[minor];
DBGin("can_select");
DBGprint(DBG_DATA,("minor = %d", minor));
#if 0
DBGprint(DBG_DATA,("file = %p", file));
;
DBGprint(DBG_DATA,("s(CanWait[]) = %2d", sizeof(CanWait[0])));
;
/* DBGprint(DBG_DATA,("s(CanWait) = %2d", sizeof(CanWait))); */
;
DBGprint(DBG_DATA,("&CanWait[] = %p", &CanWait[0]));
DBGprint(DBG_DATA,("CanWait[minor].task_list.n = %p", CanWait[minor].task_list.next));
DBGprint(DBG_DATA,("CanWait[minor].task_list.p = %p", CanWait[minor].task_list.prev));
DBGprint(DBG_DATA,("&CanWait[minor]->task_list.p = %p", (&CanWait[minor])->task_list.prev));
DBGprint(DBG_DATA,("wait = %p", wait));
if(wait) {
DBGprint(DBG_DATA,("wait->error = %d", wait->error));
DBGprint(DBG_DATA,("wait->table = %p", wait->table));
} else {
DBGprint(DBG_DATA,("can not dereference wait components"));
}
#endif
#ifdef DEBUG
CAN_ShowStat(minor);
#endif
#if LINUX_VERSION_CODE >= KERNEL_VERSION(2,3,0)
DBGprint(DBG_BRANCH,("POLL: fifo empty,poll waiting...\n"));
/* every event queue that could wake up the process
* and change the status of the poll operation
* can be added to the poll_table structure by
* calling the function poll_wait:
*/
/* _select para, wait queue, _select para */
/* X */ poll_wait(file, &CanWait[minor] , wait);
DBGprint(DBG_BRANCH,("POLL: wait returned \n"));
if( RxFifo->head != RxFifo->tail ) {
/* fifo has some telegrams */
/* Return a bit mask
* describing operations that could be immediately performed
* without blocking.
*/
DBGout();
/*
* POLLIN This bit must be set
* if the device can be read without blocking.
* POLLRDNORM This bit must be set
* if "normal'' data is available for reading.
* A readable device returns (POLLIN | POLLRDNORM)
*
*
*
*/
return POLLIN | POLLRDNORM;
}
DBGout();return 0;
#elif LINUX_VERSION_CODE >= KERNEL_VERSION(2,2,3)
DBGprint(DBG_BRANCH,("POLL: fifo empty,poll waiting...\n"));
poll_wait(file, &CanWait[minor] , wait);
DBGprint(DBG_BRANCH,("POLL: wait returned \n"));
if( RxFifo->head != RxFifo->tail ) {
/* fifo has some telegrams */
DBGout();
return POLLIN | POLLRDNORM;
}
DBGout();return 0;
#else
switch (sel_type) {
case SEL_IN:
DBGprint(DBG_BRANCH,("sel_in \n"));
if( RxFifo->head == RxFifo->tail ) {
DBGprint(DBG_BRANCH,("fifo empty \n"));
select_wait(&CanWait[minor],wait);
DBGout();return 0;
}
break;
case SEL_OUT:
DBGprint(DBG_BRANCH,("sel_out \n"));
/* ready for write ? */
select_wait(&CanWait[minor],wait);
DBGout();return 0;
}
DBGout();return 1;
#endif
DBGout();
return 0;
}