字符設(shè)備驅(qū)動程序設(shè)計

1、實驗七 字符設(shè)備驅(qū)動程序設(shè)計實驗?zāi)康恼莆兆址O(shè)備驅(qū)動程序編寫的框架；掌握設(shè)備驅(qū)動相關(guān)的知識；實驗原理參考本周大課課件字符設(shè)備驅(qū)動程序.ppt。實驗步驟建立一個工作目錄，我們的驅(qū)動程序模塊程序保存在這個目錄下；#mkdir first_drv#cd first_drv1 自己編寫一個字符設(shè)備驅(qū)動程序,程序格式參考下面；#include #include #include #include #include #include #include /（1）編寫硬件底層操作函數(shù)實現(xiàn)open,release,write,read./（2）創(chuàng)建一個file_operations結(jié)構(gòu). static int

2、_init xxx_init(void) /（3）申請設(shè)備號./（4）初始化cdev結(jié)構(gòu)./（5）注冊cdev結(jié)構(gòu).return 0; static void _exit xxx_exit(void) /注銷cdev結(jié)構(gòu)./注銷設(shè)備號 module_init(.); module_exit(.); module_license(.);注意：要求底層函數(shù)要實現(xiàn)open,release,write,read方法。2 編寫makefile文件內(nèi)容格式，參考如下：obj-m+=模塊程序文件名.oall:make -c 內(nèi)核源碼路徑 m=pwd modules #這一行要以tab鍵開頭clean:mak

3、e -c 內(nèi)核源碼路徑 m=pwd modules clean #這一行要以tab鍵開頭3 編譯模塊，拷貝到根文件系統(tǒng)中編譯內(nèi)核模塊，直接使用make命令就可以了；#make編譯沒有錯誤時，將模塊拷貝到跟文件系統(tǒng)中；#cp xxx.ko/opt/rootfs/lib/modules/3.5.0-yyy/4 啟動開發(fā)板，進入linux系統(tǒng)后，在開發(fā)板上加載和卸載模塊加載：# insmod/lib/modules/3.5.0-yyy/xxxx.ko查看系統(tǒng)分配的設(shè)備號#cat /proc/devices手動添加設(shè)備文件（設(shè)備節(jié)點）# mknod /dev/first_drv c 主設(shè)備號 次設(shè)備號

4、5 交叉編譯應(yīng)程序，打開設(shè)備文件進行讀寫操作實驗成功后，叫老師查看實驗結(jié)果，作為平時考察成績；first_drv：#include #include #include #include #include #include #include #include #include static int first_drv_open(struct inode *in, struct file *fp)printk(first driver open called!n);return 0;static int first_drv_release(struct inode *in, struct file

5、 *fp)printk(first driver release called!n);return 0;static int data=0;static ssize_t first_drv_write(struct file *fp, const char _user *buf, size_t len, loff_t *offset)copy_from_user(void *)&data,buf,sizeof(int);printk(first driver write called!data is %dn,data);return sizeof(int);static ssize_t fir

6、st_drv_read(struct file *fp, char _user *buf, size_t len, loff_t * offset)data=data+1;copy_to_user(buf,&data,sizeof(int);printk(first driver read called!n);return sizeof(int);static struct file_operations first_fops = .owner = this_module,.open = first_drv_open,.release =first_drv_release,.write = f

7、irst_drv_write,.read = first_drv_read, ;/驅(qū)動注冊static int major = 0;static struct cdev *first_drv_cdev;#define first_drv_name first_drvstatic int _init first_drv_init(void)dev_t dev;alloc_chrdev_region(&dev, 0, 1, first_drv_name);major = major(dev);first_drv_cdev = cdev_alloc();cdev_init(first_drv_cde

8、v,&first_fops);first_drv_cdev-owner = this_module;cdev_add(first_drv_cdev, dev, 1);printk(first driver module insert!n);return 0;static void _exit first_drv_exit(void)dev_t dev;dev = mkdev(major,0);cdev_del(first_drv_cdev);unregister_chrdev_region(dev, 1);printk(first driver module remove!n);module_

9、init(first_drv_init);module_exit(first_drv_exit);module_license(gpl);makefile：obj-m += first_drv.oall:make -c /home/sice/linux-4.4.19m=pwdmodulesclean:make -c /home/sice/linux-4.4.19m=pwdmodules cleantest：#include#include#include#include#include#define file_name /dev/abcint main(void)int fd;fd=open(file_name,o_r