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简单的LINUX字符设备驱动及编译进Linux内核

2019-07-12 20:51发布

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简单的LINUX字符设备驱动及编译进Linux内核…  

2010-07-06 11:23:00|  分类： 嵌入式linux|举报|字号 订阅        下载LOFTER我的照片书  | 驱动代码:   #include
#include
#include
#include
#include
#include
#include
#include
#include
#include
#include
#include
#ifndef MODULE
#define MOD_INC_USE_COUNT
#define MOD_DEC_USE_COUNT
#endif
#define MAJOR_NUM 253

MODULE_LICENSE("GPL");   int dev_test_open(struct inode *, struct file *);
ssize_t dev_test_read(struct file *, char *, size_t, loff_t *);
ssize_t dev_test_write(struct file *, const char *, size_t, loff_t *);
int dev_test_release(struct inode *, struct file *); struct file_operations hello_fops =
{
        open:dev_test_open,
        read:dev_test_read,
        write:dev_test_write,
        release:dev_test_release,
};

char *pBuff;   static int __init dev_test_init(void)
{
    printk("<1>hello dev test ");
   
    if (register_chrdev(MAJOR_NUM, "dev_test", &hello_fops))
        printk("<1>register failed ");

    return 0;
}

static void __exit dev_test_exit(void)
{
    printk("<1>bye dev_test ");
   
    if (unregister_chrdev(MAJOR_NUM, "dev_test"))
        printk("<1>unregiter failed ");
}

int dev_test_open(struct inode *pInode, struct file *pFile)
{
    pBuff = (char*)kmalloc(128, GFP_KERNEL);

    if (pBuff == NULL)
        printk("<1>kmalloc memory failed ");

    return 0;
}

int dev_test_release(struct inode *pInode, struct file *pFile)
{
    kfree(pBuff);
    return 0;
}

ssize_t dev_test_read(struct file *pFile, char *buff, size_t len, loff_t *pOff)
{
    if (copy_to_user(buff, pBuff, len))
    {

        printk("<1>copy_from_user failed ");
        return -EFAULT;
    }

    return len;
}

ssize_t dev_test_write(struct file *pFile, const char *buff, size_t len, loff_t *pOff)
{
    int i = 0;

    if (copy_from_user(pBuff, buff, len))
    {
        printk("<1>copy_to_user failed ");
        return -EFAULT;
    }
   
    while (pBuff[i] != '

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