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#ifndef _LINUX_TTY_LDISC_H

#define _LINUX_TTY_LDISC_H

/*

 * This structure defines the interface between the tty line discipline

 * implementation and the tty routines.  The following routines can be

 * defined; unless noted otherwise, they are optional, and can be

 * filled in with a null pointer.

 *

 * int  (*open)(struct tty_struct *);

 *

 *      This function is called when the line discipline is associated

 *      with the tty.  The line discipline can use this as an

 *      opportunity to initialize any state needed by the ldisc routines.

 *

 * void (*close)(struct tty_struct *);

 *

 *      This function is called when the line discipline is being

 *      shutdown, either because the tty is being closed or because

 *      the tty is being changed to use a new line discipline

 *

 * void (*flush_buffer)(struct tty_struct *tty);

 *

 *      This function instructs the line discipline to clear its

 *      buffers of any input characters it may have queued to be

 *      delivered to the user mode process.

 *

 * ssize_t (*chars_in_buffer)(struct tty_struct *tty);

 *

 *      This function returns the number of input characters the line

 *      discipline may have queued up to be delivered to the user mode

 *      process.

 *

 * ssize_t (*read)(struct tty_struct * tty, struct file * file,

 *                 unsigned char * buf, size_t nr);

 *

 *      This function is called when the user requests to read from

 *      the tty.  The line discipline will return whatever characters

 *      it has buffered up for the user.  If this function is not

 *      defined, the user will receive an EIO error.

 *

 * ssize_t (*write)(struct tty_struct * tty, struct file * file,

 *                  const unsigned char * buf, size_t nr);

 *

 *      This function is called when the user requests to write to the

 *      tty.  The line discipline will deliver the characters to the

 *      low-level tty device for transmission, optionally performing

 *      some processing on the characters first.  If this function is

 *      not defined, the user will receive an EIO error.

 *

 * int  (*ioctl)(struct tty_struct * tty, struct file * file,

 *               unsigned int cmd, unsigned long arg);

 *

 *      This function is called when the user requests an ioctl which

 *      is not handled by the tty layer or the low-level tty driver.

 *      It is intended for ioctls which affect line discpline

 *      operation.  Note that the search order for ioctls is (1) tty

 *      layer, (2) tty low-level driver, (3) line discpline.  So a

 *      low-level driver can "grab" an ioctl request before the line

 *      discpline has a chance to see it.

 *

 * long (*compat_ioctl)(struct tty_struct * tty, struct file * file,

 *                      unsigned int cmd, unsigned long arg);

 *

 *      Process ioctl calls from 32-bit process on 64-bit system

 *

 * void (*set_termios)(struct tty_struct *tty, struct ktermios * old);

 *

 *      This function notifies the line discpline that a change has

 *      been made to the termios structure.

 *

 * int  (*poll)(struct tty_struct * tty, struct file * file,

 *                poll_table *wait);

 *

 *      This function is called when a user attempts to select/poll on a

 *      tty device.  It is solely the responsibility of the line

 *      discipline to handle poll requests.

 *

 * void (*receive_buf)(struct tty_struct *, const unsigned char *cp,

 *                     char *fp, int count);

 *

 *      This function is called by the low-level tty driver to send

 *      characters received by the hardware to the line discpline for

 *      processing.  <cp> is a pointer to the buffer of input

 *      character received by the device.  <fp> is a pointer to a

 *      pointer of flag bytes which indicate whether a character was

 *      received with a parity error, etc.

 *

 * void (*write_wakeup)(struct tty_struct *);

 *

 *      This function is called by the low-level tty driver to signal

 *      that line discpline should try to send more characters to the

 *      low-level driver for transmission.  If the line discpline does

 *      not have any more data to send, it can just return.

 *

 * int (*hangup)(struct tty_struct *)

 *

 *      Called on a hangup. Tells the discipline that it should

 *      cease I/O to the tty driver. Can sleep. The driver should

 *      seek to perform this action quickly but should wait until

 *      any pending driver I/O is completed.

 */

#include <linux/fs.h>

#include <linux/wait.h>

struct tty_ldisc {

        int     magic;

        char    *name;

        int     num;

        int     flags;

        /*

         * The following routines are called from above.

         */

        int     (*open)(struct tty_struct *);

        void    (*close)(struct tty_struct *);

        void    (*flush_buffer)(struct tty_struct *tty);

        ssize_t (*chars_in_buffer)(struct tty_struct *tty);

        ssize_t (*read)(struct tty_struct * tty, struct file * file,

                        unsigned char __user * buf, size_t nr);

        ssize_t (*write)(struct tty_struct * tty, struct file * file,

                         const unsigned char * buf, size_t nr);

        int     (*ioctl)(struct tty_struct * tty, struct file * file,

                         unsigned int cmd, unsigned long arg);

        long    (*compat_ioctl)(struct tty_struct * tty, struct file * file,

                                unsigned int cmd, unsigned long arg);

        void    (*set_termios)(struct tty_struct *tty, struct ktermios * old);

        unsigned int (*poll)(struct tty_struct *, struct file *,

                             struct poll_table_struct *);

        int     (*hangup)(struct tty_struct *tty);

        /*

         * The following routines are called from below.

         */

        void    (*receive_buf)(struct tty_struct *, const unsigned char *cp,

                               char *fp, int count);

        void    (*write_wakeup)(struct tty_struct *);

        struct  module *owner;

        int refcount;

};

#define TTY_LDISC_MAGIC 0x5403

#define LDISC_FLAG_DEFINED      0x00000001

#define MODULE_ALIAS_LDISC(ldisc) \

        MODULE_ALIAS("tty-ldisc-" __stringify(ldisc))

#endif /* _LINUX_TTY_LDISC_H */