s3c2440驱动

#include <linux/module.h>

#include <linux/kernel.h>

#include <asm/uaccess.h> //copy_to_use, copy_from_user

#include <linux/serial_core.h>

#include <asm/plat-s3c/regs-serial.h> //寄存器宏

#include <asm/io.h> //readl, readb, writel, writeb

#define BUFSIZE 100

#define ttyS0_MAJOR 240

#define iobase S3C24XX_VA_UART1

#define UART_ULCON1 iobase

#define UART_UCON1 iobase + 0x4

#define UART_UFCON1 iobase + 0x8

#define UART_UTRSTAT1 iobase + 0x10

#define UART_UTXH1 iobase + 0x20

#define UART_URXH1 iobase + 0x24

#define UART_UBRDIV1 iobase + 0x28

MODULE_AUTHOR("sunsea");

MODULE_DESCRIPTION("s3c2440 serial driver");

MODULE_LICENSE("GPL");

int sunsea_open(struct inode *inode, struct file *filp)

{

writel(3, UART_ULCON1);

writel(5, UART_UCON1);

writel(26, UART_UBRDIV1);

return 0;

}

ssize_t sunsea_write(struct file *filp, const char __user *buf, size_t count, loff_t *f_pos)

{

char wbuf[BUFSIZE] = {0};

int state;

int i = 0;

copy_from_user(wbuf, buf, count);

while(wbuf[i] != '/0')

{

state = readl(UART_UTRSTAT1);

if((0x02 & state) == 2)

{

writeb(wbuf[i], UART_UTXH1);

i++;

}

}

return 0;

}

ssize_t sunsea_read(struct file *filp, char __user *buf, size_t count, loff_t *f_ops)

{

char rbuf[1] = {0};

int state;

state = readl(UART_UTRSTAT1);

if((0x01 & state) == 1)

{

rbuf[0] = readb(UART_URXH1);

copy_to_user(buf, rbuf, 1);

}

else

{

set_current_state(TASK_INTERRUPTIBLE);

schedule_timeout(10);

}

return 0; 

}

int sunsea_release(struct inode *inode, struct file *filp)

{

return 0;

}

struct file_operations ttyS0_fops = 

{

.owner = THIS_MODULE,

.open = sunsea_open,

.write = sunsea_write,

.read = sunsea_read,

.release = sunsea_release,

};

int __init

sunsea_init(void)

{

int rc;

printk("s3c2440 serial module loaded!/n"); 

rc = register_chrdev(ttyS0_MAJOR, "ttyS0", &ttyS0_fops);

if(rc < 0)

{

printk("Error: register ttyS0 device error!/n") ;

return -1;

}

return 0; 

}

void __exit

sunsea_exit(void)

{

unregister_chrdev(ttyS0_MAJOR, "ttyS0");

printk("s3c2440 serial module exit!/n"); 

return;

}

module_init(sunsea_init);

module_exit(sunsea_exit);