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-rw-r--r--include/linux/tty_ldisc.h154
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diff --git a/include/linux/tty_ldisc.h b/include/linux/tty_ldisc.h
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+++ b/include/linux/tty_ldisc.h
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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.
+ *
+ * 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 */