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/* char.c
*字符设备驱动模板，用于快速建立驱动框架
*/
#include <linux/module.h> /*__init, __exit, module_init*/
#include <linux/types.h> /* size_t */
#include <linux/fs.h> /*file_operations*/
#include <linux/cdev.h> /*stuct cdev*/
#include "char.h"
static int xxx_major = 0;
static int xxx_minor = 0;
struct xxx_devt
{
struct cdev cdev;
//....
}xxx_dev;
static ssize_t xxx_read(struct file *filp, char __user *buf, size_t count, loff_t *f_pos)
{
struct xxx_devt *dev=filp->private_data;/*读取私有数据*/
//...
copy_to_user();/*设备到用户空间*/
//...
}
static ssize_t xxx_write(struct file *filp, char __user *buf, size_t count, loff_t *f_pos)
{
struct xxx_devt *dev=filp->private_data;/*读取私有数据*/
//...
copy_from_user();/*用户空间到设备*/
//...
}
static int xxx_open(struct inode *inode, struct file *filp)
{
filp->private_data = &xxx_dev;/*私有数据指针传递数据*/
//...
}
static int xxx_ioctl(struct inode *inodep,struct file *filp,unsigned int cmd, unsigned long arg)
{
int err = 0;
int retval;
int tmp;
/* don't even decode wrong cmds: better returning ENOTTY than EFAULT */
if (_IOC_TYPE(cmd) != XXX_IOC_MAGIC)
return -ENOTTY;
if (_IOC_NR(cmd) > XXX_IOC_MAXNR)
return -ENOTTY;
switch(cmd) {
case XXX_IOCRESET:
reset();
break;
case XXX_IOCGQUANTUM:
retval = __put_user(tmp, (int __user *)arg);/*把数据从驱动传到用户空间*/
break;
case XXX_IOCSQSET:
if (! capable (CAP_SYS_ADMIN))
return -EPERM;
retval = __get_user(tmp, (int __user *)arg);/*把数据从用户空间传到驱动*/
break;
case XXX_IOCXQSET:
if (! capable (CAP_SYS_ADMIN))
return -EPERM;
retval = __get_user(tmp, (int __user *)arg);
if(retval == 0)
retval = __put_user(tmp, (int __user *)arg);
break;
default:
return -ENOTTY;
}
}
static struct file_operations xxx_fops =
{
.owner =THIS_MODULE,
.read =xxx_read,
.write =xxx_write,
.open =xxx_open,
.ioctl =xxx_ioctl,
// .close =xxx_close,
};
static int __init xxx_init(void)
{
int rt;
int count=1;
dev_t dev;
if(xxx_major) /*获取设备号*/
{
dev = MKDEV(xxx_major,xxx_minor);
rt = register_chrdev_region(dev, count, "xxx");
} else {
rt = alloc_chrdev_region(&dev, xxx_minor, count, "xxx");
xxx_major = MAJOR(dev);
}
if(rt < 0)
printk(KERN_WARNING"Major Error!\n");
dev = MKDEV(xxx_major, 0);
cdev_init(&xxx_dev.cdev, &xxx_fops);
xxx_dev.cdev.owner = THIS_MODULE;
xxx_dev.cdev.ops = &xxx_fops;
rt = cdev_add(&xxx_dev.cdev, dev, count);
if( rt )
{
printk(KERN_WARNING"Cdev Add Error!\n");
cdev_del(&xxx_dev.cdev);
return -1;
}
return 0;
}
static void __exit xxx_exit(void)
{
cdev_del(&xxx_dev.cdev);
unregister_chrdev_region(MKDEV (xxx_major, xxx_minor), 1);
}
module_init(xxx_init);
module_exit(xxx_exit);
MODULE_AUTHOR("gfy @ CQUPT");
MODULE_DESCRIPTION("Character Driver Model");
MODULE_LICENSE("GPL");
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