1 files changed, 233 insertions, 0 deletions
diff --git a/include/linux/tty_ldisc.h b/include/linux/tty_ldisc.h
new file mode 100644
index 000000000..00c9d688d
--- /dev/null
+++ b/include/linux/tty_ldisc.h
@@ -0,0 +1,233 @@
+#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. <fp> may be NULL to indicate
+ *	all data received is TTY_NORMAL.
+ *
+ * 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. If the line
+ *	discipline does have some data to send, please arise a tasklet
+ *	or workqueue to do the real data transfer. Do not send data in
+ *	this hook, it may leads to a deadlock.
+ *
+ * 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.
+ *
+ * void (*fasync)(struct tty_struct *, int on)
+ *
+ *	Notify line discipline when signal-driven I/O is enabled or
+ *	disabled.
+ *
+ * void (*dcd_change)(struct tty_struct *tty, unsigned int status)
+ *
+ *	Tells the discipline that the DCD pin has changed its status.
+ *	Used exclusively by the N_PPS (Pulse-Per-Second) line discipline.
+ *
+ * int	(*receive_buf2)(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. <fp> may be NULL to indicate
+ *	all data received is TTY_NORMAL.
+ *	If assigned, prefer this function for automatic flow control.
+ */
+
+#include <linux/fs.h>
+#include <linux/wait.h>
+
+
+/*
+ * the semaphore definition
+ */
+struct ld_semaphore {
+	long			count;
+	raw_spinlock_t		wait_lock;
+	unsigned int		wait_readers;
+	struct list_head	read_wait;
+	struct list_head	write_wait;
+#ifdef CONFIG_DEBUG_LOCK_ALLOC
+	struct lockdep_map	dep_map;
+#endif
+};
+
+extern void __init_ldsem(struct ld_semaphore *sem, const char *name,
+			 struct lock_class_key *key);
+
+#define init_ldsem(sem)						\
+do {								\
+	static struct lock_class_key __key;			\
+								\
+	__init_ldsem((sem), #sem, &__key);			\
+} while (0)
+
+
+extern int ldsem_down_read(struct ld_semaphore *sem, long timeout);
+extern int ldsem_down_read_trylock(struct ld_semaphore *sem);
+extern int ldsem_down_write(struct ld_semaphore *sem, long timeout);
+extern int ldsem_down_write_trylock(struct ld_semaphore *sem);
+extern void ldsem_up_read(struct ld_semaphore *sem);
+extern void ldsem_up_write(struct ld_semaphore *sem);
+
+#ifdef CONFIG_DEBUG_LOCK_ALLOC
+extern int ldsem_down_read_nested(struct ld_semaphore *sem, int subclass,
+				  long timeout);
+extern int ldsem_down_write_nested(struct ld_semaphore *sem, int subclass,
+				   long timeout);
+#else
+# define ldsem_down_read_nested(sem, subclass, timeout)		\
+		ldsem_down_read(sem, timeout)
+# define ldsem_down_write_nested(sem, subclass, timeout)	\
+		ldsem_down_write(sem, timeout)
+#endif
+
+
+struct tty_ldisc_ops {
+	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 *);
+	void	(*dcd_change)(struct tty_struct *, unsigned int);
+	void	(*fasync)(struct tty_struct *tty, int on);
+	int	(*receive_buf2)(struct tty_struct *, const unsigned char *cp,
+				char *fp, int count);
+
+	struct  module *owner;
+
+	int refcount;
+};
+
+struct tty_ldisc {
+	struct tty_ldisc_ops *ops;
+	struct tty_struct *tty;
+};
+
+#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 */