isa.c

一个很简洁的linux下isa总线驱动

#include <linux/config.h>
#include <linux/module.h>
#include <linux/version.h>
#include <linux/types.h>
#include <linux/errno.h>
#include <linux/kernel.h>
#include <linux/sched.h>
#include <linux/slab.h>
#include <linux/ioport.h>
#include <linux/fcntl.h>
#include <asm/io.h>
#include <asm/uaccess.h>
#include <asm/system.h>
#include <linux/init.h>
#include <linux/fs.h>
#include "isadev.h"

static unsigned long isa_is_open;
static int expect_close;
static int rd_offset,wr_offset;

static int memBase=0x00000;
static int range = 0x10000;

static ssize_t isa_write(struct file *file, const char *buf, size_t count, loff_t *ppos)
{
	size_t written=0;
	unsigned long p=memBase;
	p+=wr_offset;

#ifdef __DEBUG__
	printk("base addr: 0x%x + 0x%x\n",memBase,wr_offset);
#endif
	if (copy_from_user(__va(p),buf,count))
		return -EFAULT;
	written+=count;
	p+=count;

#ifdef __DEBUG__
	int i;
	printk("Kernel write:\n");
	for (i=0;i<count;i++)
		printk("%c ",buf[i]);
		printk("\n");
#endif
	
	return written;
}

static ssize_t isa_read(struct file *file, char *buf, size_t count, loff_t *ppos)
{
#ifdef __DEBUG__
	int i;
#endif
	size_t read=0;
	unsigned long p=memBase;

	p+=rd_offset;
#ifdef __DEBUG__
	printk("base addr: 0x%x + 0x%x\n",memBase,rd_offset);
#endif
	if (copy_to_user(buf,__va(p),count))
		return -EFAULT;
	read+=count;
	p+=count;

#ifdef __DEBUG__
	printk("Kernel read:\n");
	for (i=0;i<count;i++)
		printk("%x ",buf[i]&0x0ff);
		printk("\n");
#endif
	return read;
}

static int isa_ioctl(struct inode *inode, struct file *file, unsigned int cmd,
	unsigned long arg)
{
#ifdef __DEBUG__
	printk(KERN_INFO"ioctl exec\n");
#endif
	switch (cmd)
	{
		default:
			return -ENODEV;
		case RD_OFFSET:
			get_user(rd_offset, (int *)arg);
		#ifdef __DEBUG__
			printk("rd_offset = %d\n",rd_offset);
		#endif
			break;
		case WR_OFFSET:
			get_user(wr_offset, (int *)arg);
		#ifdef __DEBUG__
			printk("wr_offset = %d\n",wr_offset);
		#endif
			break;
	}
	return 0;
}

static int isa_open(struct inode *inode, struct file *file)
{
	if (MAJOR(inode->i_rdev) != isa_major)
	{
		printk(KERN_ERR"Can not open device\n");
		return -ENODEV;
	}
#ifdef __DEBUG__
	printk("Device Major: %d\n",MAJOR(inode->i_rdev));
#endif
//	MOD_INC_USE_COUNT;
	return 0;
}

static int isa_release(struct inode *inode, struct file *file)
{
//	MOD_DEC_USE_COUNT;
	return 0;
}

static struct file_operations isa_fops = {
	.owner=		THIS_MODULE,
	.llseek=	NULL,
	.read=		isa_read,
	.write=		isa_write,
	.ioctl=		isa_ioctl,
	.open=		isa_open,
	.release=	isa_release,
};

static void __exit isa_exit(void)
{
	unregister_chrdev(isa_major,NAME);
	release_mem_region(memBase,range);
}

static int __init isa_init(void)
{
	int ret=0;
	if (ret=register_chrdev(isa_major,NAME,&isa_fops)<0)
	{
		printk(KERN_ERR"Register"NAME"Dev Error ");
		return  ret;
	}
	if (check_mem_region(0xd0000,range))
	{
		printk(KERN_ERR"Check_Region ERROR\n");
		unregister_chrdev(isa_major,NAME);
		return -1;
	}

	if (!request_mem_region(0xd0000, range, "isa"))
	{
		printk(KERN_ERR"Request Region ERROR\n");
		unregister_chrdev(isa_major,NAME);
		ret = -1;
	}
	return ret;
}

module_init(isa_init);
module_exit(isa_exit);

MODULE_AUTHOR("Senbo");
MODULE_LICENSE("GPL");
EXPORT_NO_SYMBOLS;