字符设备驱动源码分析

• 主要数据结构
• • file_operations
  • miscdevice
  • platform_device

主要数据结构

file_operations

结构体 file_operations 在头文件 kernel-4.9/include/linux/fs.h 中声明如下

struct file_operations {
        struct module *owner;
        loff_t (*llseek) (struct file *, loff_t, int);
        ssize_t (*read) (struct file *, char __user *, size_t, loff_t *);
        ssize_t (*write) (struct file *, const char __user *, size_t, loff_t *);
        ssize_t (*read_iter) (struct kiocb *, struct iov_iter *);
        ssize_t (*write_iter) (struct kiocb *, struct iov_iter *);
        int (*iterate) (struct file *, struct dir_context *);
        int (*iterate_shared) (struct file *, struct dir_context *);
        unsigned int (*poll) (struct file *, struct poll_table_struct *);
        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 *, loff_t, loff_t, 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);
        unsigned long (*get_unmapped_area)(struct file *, unsigned long, unsigned long, unsigned long, unsigned long);
        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 **, void **);
        long (*fallocate)(struct file *file, int mode, loff_t offset,
                          loff_t len);
        void (*show_fdinfo)(struct seq_file *m, struct file *f);
#ifndef CONFIG_MMU
        unsigned (*mmap_capabilities)(struct file *);
#endif
        ssize_t (*copy_file_range)(struct file *, loff_t, struct file *,
                        loff_t, size_t, unsigned int);
        int (*clone_file_range)(struct file *, loff_t, struct file *, loff_t,
                        u64);
        ssize_t (*dedupe_file_range)(struct file *, u64, u64, struct file *,
                        u64);
};

miscdevice

结构体 miscdevice 于kernel-4.9/include/linux/miscdevice.h 中声明如下：

struct miscdevice  {
        int minor;
        const char *name;
        const struct file_operations *fops;
        struct list_head list;
        struct device *parent;
        struct device *this_device;
        const struct attribute_group **groups;
        const char *nodename;
        umode_t mode;
};

platform_device

结构体 platform_device 于kernel-4.9/include/linux/platform_device .h 中声明如下：

struct platform_device {
        const char      *name;
        int             id;
        bool            id_auto;
        struct device   dev;
        u32             num_resources;
        struct resource *resource;

        const struct platform_device_id *id_entry;
        char *driver_override; /* Driver name to force a match */

        /* MFD cell pointer */
        struct mfd_cell *mfd_cell;

        /* arch specific additions */
        struct pdev_archdata    archdata;
};