裝置驅動基本格式介紹

struct file_operations {

struct module *owner;//模組所有者指標,一般初始化為this_modules

loff_t (*llseek) (struct file *, loff_t, int);//用來修改檔案當前的讀寫位置,返回新的位置loff_t 為乙個"長偏移"

ssize_t (*read) (struct file *, char __user *, size_t, loff_t *);//同步讀取函式,讀取成功返回讀取的位元組數,設定為null,呼叫時返回-einval

ssize_t (*write) (struct file *, const char __user *, size_t, loff_t *);//同步寫入函式

ssize_t (*aio_read) (struct kiocb *, const struct iovec *, unsigned long, loff_t);//非同步讀取操作,為null時全部通過read處理

ssize_t (*aio_write) (struct kiocb *, const struct iovec *, unsigned long, loff_t);//非同步寫入函式

int (*readdir) (struct file *, void *, filldir_t);//僅用於讀取目錄,對裝置檔案,該字段為null

unsigned int (*poll) (struct file *, struct poll_table_struct *);//判斷目前是否可以對裝置進行讀寫操作,欄位為空時,裝置會被認為既可讀也可寫

int (*ioctl) (struct inode *, struct file *, unsigned int, unsigned long);//向裝置傳送i/o控制命令的函式,不設定入口點返回-enotty

long (*unlocked_ioctl) (struct file *, unsigned int, unsigned long);

long (*compat_ioctl) (struct file *, unsigned int, unsigned long);

int (*mmap) (struct file *, struct vm_area_struct *);

int (*open) (struct inode *, struct file *);

int (*flush) (struct file *, fl_owner_t id);

int (*release) (struct inode *, struct file *);

int (*fsync) (struct file *, struct dentry *, int datasync);

int (*aio_fsync) (struct kiocb *, int datasync);

int (*fasync) (int, struct file *, int);

int (*lock) (struct file *, int, struct file_lock *);

ssize_t (*sendpage) (struct file *, struct page *, int, size_t, loff_t *, int);

int (*check_flags)(int);

int (*flock) (struct file *, int, struct file_lock *);

ssize_t (*splice_write)(struct pipe_inode_info *, struct file *, loff_t *, size_t, unsigned int);

ssize_t (*splice_read)(struct file *, loff_t *, struct pipe_inode_info *, size_t, unsigned int);

int (*setlease)(struct file *, long, struct file_lock **);