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Diffstat (limited to 'include/linux/tty_ldisc.h')
| -rw-r--r-- | include/linux/tty_ldisc.h | 154 |
1 files changed, 154 insertions, 0 deletions
diff --git a/include/linux/tty_ldisc.h b/include/linux/tty_ldisc.h new file mode 100644 index 000000000000..6066afde5ce4 --- /dev/null +++ b/include/linux/tty_ldisc.h @@ -0,0 +1,154 @@ +#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. + * + * void (*set_termios)(struct tty_struct *tty, struct termios * 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. + * + * int (*receive_room)(struct tty_struct *); + * + * This function is called by the low-level tty driver to + * determine how many characters the line discpline can accept. + * The low-level driver must not send more characters than was + * indicated by receive_room, or the line discpline may drop + * those characters. + * + * 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); + void (*set_termios)(struct tty_struct *tty, struct termios * 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); + int (*receive_room)(struct tty_struct *); + 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 */ |