如何编写LINUX设备驱动程序

yyykkk1229

http://www.it.com.cn/f/edu/0411/30/53811.htm
按照上面连接的范例想要编写设备驱动程序
得到如下错误,请教高手该如何修改
test.c:13: warning: `struct file' declared inside parameter list
test.c:13: warning: its scope is only this definition or declaration, which is probably not what you want
test.c:13: warning: `struct inode' declared inside parameter list
test.c: In function `read_test':
test.c:18: `VERIFY_WRITE' undeclared (first use in this function)
test.c:18: (Each undeclared identifier is reported only once
test.c:18: for each function it appears in.)
test.c:21: parse error before "for"
test.c: At top level:
test.c:30: warning: `struct file' declared inside parameter list
test.c:30: warning: `struct inode' declared inside parameter list
test.c:35: warning: `struct file' declared inside parameter list
test.c:35: warning: `struct inode' declared inside parameter list
test.c: In function `open_tibet':
test.c:37: `MOD_ING_USE_COUNT' undeclared (first use in this function)
test.c: At top level:
test.c:41: warning: `struct file' declared inside parameter list
test.c:41: warning: `struct inode' declared inside parameter list
test.c: In function `release_tibet':
test.c:43: union has no member named `usecount'
test.c: At top level:
test.c:46: variable `test_fops' has initializer but incomplete type
test.c:47: warning: excess elements in struct initializer
test.c:47: warning: (near initialization for `test_fops')
test.c:48: warning: excess elements in struct initializer
test.c:48: warning: (near initialization for `test_fops')
test.c:49: `write_test' undeclared here (not in a function)
test.c:49: warning: excess elements in struct initializer
test.c:49: warning: (near initialization for `test_fops')
test.c:50: warning: excess elements in struct initializer
test.c:50: warning: (near initialization for `test_fops')
test.c:51: warning: excess elements in struct initializer
test.c:51: warning: (near initialization for `test_fops')
test.c:52: warning: excess elements in struct initializer
test.c:52: warning: (near initialization for `test_fops')
test.c:53: warning: excess elements in struct initializer
test.c:53: warning: (near initialization for `test_fops')
test.c:54: `open_test' undeclared here (not in a function)
test.c:54: warning: excess elements in struct initializer
test.c:54: warning: (near initialization for `test_fops')
test.c:55: `release_test' undeclared here (not in a function)
test.c:55: warning: excess elements in struct initializer
test.c:55: warning: (near initialization for `test_fops')
test.c:56: warning: excess elements in struct initializer
test.c:56: warning: (near initialization for `test_fops')
test.c:57: warning: excess elements in struct initializer
test.c:57: warning: (near initialization for `test_fops')
test.c: In function `init_module':
test.c:64: parse error before '=' token
test.c:67: `KERN_INFO' undeclared (first use in this function)
test.c:67: parse error before string constant
/usr/include/linux/timer.h: At top level:
test.c:46: storage size of `test_fops' isn't known

<LINUX设备驱动>那本书的第三章看完了，但由于没有具体例子,很多地方都搞不懂,麻烦高手帮忙,谢谢!!!

dreamice

原帖由 yyykkk1229 于 2008-8-7 16:37 发表
非常感谢楼上的回答，虽然说自己还是很模糊
慢慢琢磨吧，哎．．．现在思路有些乱

给lz提几点建议：
1、内核源码版本最好和系统版本要一致；
2、不要什么头文件都一骨碌弄进去，哪个函数需要哪个头文件，搞清楚了再说；
3、调用的函数有什么作用，参数的意义，都搞明确；
4、Makefile的写法，应该明确一些。

yyykkk1229

顶一下........

sep

Linux设备驱动不是有一个最简单的例子吗？hello world的那个

yyykkk1229

hello world 只是模块的加载啊
驱动设备的加载我没有找到想对应的例子,我用的是2.4.20-8版本,可能是编写版本的冲突啊
谁能给个2.4.20-8版本的范例,最简单的就可以了,只是为了了解这个过程,谢谢

dreamice

/*  hello-1.c - The simplest kernel module.
*/
#include <linux/module.h>  /* Needed by all modules */
#include <linux/kernel.h>  /* Needed for KERN_ALERT */


int init_module(void)
{
   printk("<1>Hello world 1.\n");
       
   // A non 0 return means init_module failed; module can't be loaded.
   return 0;
}


void cleanup_module(void)
{
  printk(KERN_ALERT "Goodbye world 1.\n");
}  

把这个在2.4下面实现一下吧。

makefile：
TARGET  := hello-1
WARN    := -W -Wall -Wstrict-prototypes -Wmissing-prototypes
INCLUDE := -isystem /lib/modules/`uname -r`/build/include
CFLAGS  := -O2 -DMODULE -D__KERNEL__ ${WARN} ${INCLUDE}
CC      := gcc-3.0
       
${TARGET}.o: ${TARGET}.c

.PHONY: clean

clean:
    rm -rf {TARGET}.o

yyykkk1229

楼上的,非常感谢你的程序,那你没有理解我的意思,模块的编译我已经会了,我需要一个驱动设备的程序,2者是不一样的,编译后的.o文件是能连接到/dev当中的,驱动设备比模块要复杂许多,不过还是非常感谢你的回答~

[ 本帖最后由 yyykkk1229 于 2008-8-7 11:40 编辑 ]

dreamice

你试试这个，虚拟的一个设备，/dev/hello

1. 
   
2. /*  chardev.c: Creates a read-only char device that says how many times
   
3. *  you've read from the dev file
   
4. */
   
5.        
   
6.         #if defined(CONFIG_MODVERSIONS) && ! defined(MODVERSIONS)
   
7.            #include <linux/modversions.h>
   
8.            #define MODVERSIONS
   
9.         #endif
   
10.         #include <linux/kernel.h>
    
11.         #include <linux/module.h>
    
12.         #include <linux/fs.h>
    
13.         #include <asm/uaccess.h>  /* for put_user */
    
14.        
    
15.         /*  Prototypes - this would normally go in a .h file
    
16.          */
    
17.         int init_module(void);
    
18.         void cleanup_module(void);
    
19.         static int device_open(struct inode *, struct file *);
    
20.         static int device_release(struct inode *, struct file *);
    
21.         static ssize_t device_read(struct file *, char *, size_t, loff_t *);
    
22.         static ssize_t device_write(struct file *, const char *, size_t, loff_t *);
    
23.        
    
24.         #define SUCCESS 0
    
25.         #define DEVICE_NAME "chardev" /* Dev name as it appears in /proc/devices   */
    
26.         #define BUF_LEN 80            /* Max length of the message from the device */
    
27.        
    
28.        
    
29.         /* Global variables are declared as static, so are global within the file. */
    
30.        
    
31.         static int Major;            /* Major number assigned to our device driver */
    
32.         static int Device_Open = 0;  /* Is device open?  Used to prevent multiple  */
    
33.                                         access to the device                       */
    
34.         static char msg[BUF_LEN];    /* The msg the device will give when asked    */
    
35.         static char *msg_Ptr;
    
36.        
    
37.         static struct file_operations fops = {
    
38.           .read = device_read,
    
39.           .write = device_write,
    
40.           .open = device_open,
    
41.           .release = device_release
    
42.         };
    
43.        
    
44.        
    
45.         /*                   Functions
    
46.          */
    
47.        
    
48.         int init_module(void)
    
49.         {
    
50.            Major = register_chrdev(0, DEVICE_NAME, &fops);
    
51.        
    
52.            if (Major < 0) {
    
53.              printk ("Registering the character device failed with %d\n", Major);
    
54.              return Major;
    
55.            }
    
56.        
    
57.            printk("<1>I was assigned major number %d.  To talk to\n", Major);
    
58.            printk("<1>the driver, create a dev file with\n");
    
59.                  printk("'mknod /dev/hello c %d 0'.\n", Major);
    
60.            printk("<1>Try various minor numbers.  Try to cat and echo to\n");
    
61.                  printk("the device file.\n");
    
62.            printk("<1>Remove the device file and module when done.\n");
    
63.        
    
64.            return 0;
    
65.         }
    
66.        
    
67.        
    
68.         void cleanup_module(void)
    
69.         {
    
70.            /* Unregister the device */
    
71.            int ret = unregister_chrdev(Major, DEVICE_NAME);
    
72.            if (ret < 0) printk("Error in unregister_chrdev: %d\n", ret);
    
73.         }  
    
74.        
    
75.        
    
76.         /*                   Methods
    
77.          */
    
78.        
    
79.         /* Called when a process tries to open the device file, like
    
80.          * "cat /dev/mycharfile"
    
81.          */
    
82.         static int device_open(struct inode *inode, struct file *file)
    
83.         {
    
84.            static int counter = 0;
    
85.            if (Device_Open) return -EBUSY;
    
86.            Device_Open++;
    
87.            sprintf(msg,"I already told you %d times Hello world!\n", counter++");
    
88.            msg_Ptr = msg;
    
89.            MOD_INC_USE_COUNT;
    
90.        
    
91.           return SUCCESS;
    
92.         }
    
93.        
    
94.        
    
95.         /* Called when a process closes the device file.
    
96.          */
    
97.         static int device_release(struct inode *inode, struct file *file)
    
98.         {
    
99.            Device_Open --;     /* We're now ready for our next caller */
    
100.        
     
101.            /* Decrement the usage count, or else once you opened the file, you'll
     
102.                     never get get rid of the module. */
     
103.            MOD_DEC_USE_COUNT;
     
104.        
     
105.            return 0;
     
106.         }
     
107.        
     
108.        
     
109.         /* Called when a process, which already opened the dev file, attempts to
     
110.            read from it.
     
111.         */
     
112.         static ssize_t device_read(struct file *filp,
     
113.            char *buffer,    /* The buffer to fill with data */
     
114.            size_t length,   /* The length of the buffer     */
     
115.            loff_t *offset)  /* Our offset in the file       */
     
116.         {
     
117.            /* Number of bytes actually written to the buffer */
     
118.            int bytes_read = 0;
     
119.        
     
120.            /* If we're at the end of the message, return 0 signifying end of file */
     
121.            if (*msg_Ptr == 0) return 0;
     
122.        
     
123.            /* Actually put the data into the buffer */
     
124.            while (length && *msg_Ptr)  {
     
125.        
     
126.                 /* The buffer is in the user data segment, not the kernel segment;
     
127.                  * assignment won't work.  We have to use put_user which copies data from
     
128.                  * the kernel data segment to the user data segment. */
     
129.               put_user(*(msg_Ptr++), buffer++);
     
130.        
     
131.               length--;
     
132.               bytes_read++;
     
133.            }
     
134.        
     
135.            /* Most read functions return the number of bytes put into the buffer */
     
136.            return bytes_read;
     
137.         }
     
138.        
     
139.        
     
140.         /*  Called when a process writes to dev file: echo "hi" > /dev/hello */
     
141.         static ssize_t device_write(struct file *filp,
     
142.            const char *buff,
     
143.                  size_t len,
     
144.                  loff_t *off)
     
145.         {
     
146.            printk ("<1>Sorry, this operation isn't supported.\n");
     
147.            return -EINVAL;
     
148.         }
     

复制代码

makefile 我就不说了，自己编译，试一下。

yyykkk1229

感谢,可是还是同样的错误,说出现fops时出错,跟我刚才的问题一样,我刚才设置那个文件是用的是test_fops
Major = register_chrdev(0, DEVICE_NAME, &fops);
这句话的DEVICE_NAME应该如何设置呀

dreamice

原帖由 yyykkk1229 于 2008-8-7 13:50 发表
感谢,可是还是同样的错误,说出现fops时出错,跟我刚才的问题一样,我刚才设置那个文件是用的是test_fops
Major = register_chrdev(0, DEVICE_NAME, &fops);
这句话的DEVICE_NAME应该如何设置呀

DEVICE_NAME前面不是有宏定义吗？你可不可以把你的makefile贴出来看看？