open.c

can bus driver code.

/* open.c
 * Linux CAN-bus device driver.
 * Written by Arnaud Westenberg email:[e-mail]
 * This software is released under the GPL-License.
 * Version 0.7  6 Aug 2001
 */

#define __NO_VERSION__
#include <linux/module.h> 

#include <linux/autoconf.h>
#if defined (CONFIG_MODVERSIONS) && !defined (MODVERSIONS)
#define MODVERSIONS
#endif

#if defined (MODVERSIONS)
#include <linux/modversions.h>
#endif

#include <linux/fs.h>
#include <linux/malloc.h>
#include <linux/version.h>

#include "../include/main.h"
#include "../include/open.h"
#include "../include/i82527.h"
#include "../include/setup.h"

int can_open(struct inode *inode, struct file *file)
{
	struct msgobj_t *obj;
	struct chip_t *chip;
	struct canfifo_t *fifo;

	if ( ((obj=objects_p[MINOR_NR]) == NULL) || 
			((chip=objects_p[MINOR_NR]->hostchip) == NULL) ) {
		CANMSG("There is no hardware support for the device file with minor nr.: %d\n",MINOR_NR);
		return -ENODEV;
	}

	if (objects_p[MINOR_NR]->flags & OPENED) {
		CANMSG("Sorry, only single open per device file.\n");
		return -EBUSY;
	}
	else
		objects_p[MINOR_NR]->flags |= OPENED;

	if (chip->flags & CONFIGURED) 
		DEBUGMSG("Device is already configured.\n");
	else {
		if (chip->chipspecops->chip_config(chip))
			CANMSG("Error configuring chip.\n");
		else
			chip->flags |= CONFIGURED; 
	} /* End of chip configuration */

	/* Allocate output buffer memory for the opened device */
	fifo = objects_p[MINOR_NR]->fifo;
	fifo->buf_tx_entry=(struct canmsg_t *)kmalloc(MAX_BUF_LENGTH * sizeof(struct canmsg_t), GFP_KERNEL);
	if (fifo->buf_tx_entry == NULL)
		return -ENOMEM;
	else
		if ( add_mem_to_list(fifo->buf_tx_entry) )
			return -ENOMEM;
	/* Allocate input buffer memory for the opened device */
	fifo->buf_rx_entry=(struct canmsg_t *)kmalloc(MAX_BUF_LENGTH * sizeof(struct canmsg_t), GFP_KERNEL);
	if (fifo->buf_rx_entry == NULL)
		return -ENOMEM;
	else
		if ( add_mem_to_list(fifo->buf_rx_entry) )
			return -ENOMEM;

	/* In- and output buffer initialization */
	fifo->tx_readp = fifo->buf_tx_entry;
	fifo->tx_writep = fifo->buf_tx_entry;
	fifo->rx_readp = fifo->buf_rx_entry;
	fifo->rx_writep = fifo->buf_rx_entry;
	fifo->rx_size = MAX_BUF_LENGTH * sizeof(struct canmsg_t);
	fifo->tx_size = fifo->rx_size;

#if (LINUX_VERSION_CODE <= KERNEL_VERSION(2,2,19))
	init_waitqueue(&fifo->readq);
	init_waitqueue(&fifo->writeq);
#else
	init_waitqueue_head(&fifo->readq);
	init_waitqueue_head(&fifo->writeq);
#endif

	fifo->rx_in_progress = 0;
	fifo->tx_in_progress = 0;

	fifo->head = fifo->tail = 0; //TEMP!!

	if (chip->chipspecops->pre_read_config(chip,obj)<0)
		CANMSG("Error initializing chip for receiving\n");
		
	MOD_INC_USE_COUNT;
	
	return 0;
}