|
/* * This structure defines the interface between the low-level tty * driver 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 * tty, struct file * filp); * * This routine is called when a particular tty device is opened. * This routine is mandatory; if this routine is not filled in, * the attempted open will fail with ENODEV. * * Required method. * * void (*close)(struct tty_struct * tty, struct file * filp); * * This routine is called when a particular tty device is closed. * * Required method. * * int (*write)(struct tty_struct * tty, * const unsigned char *buf, int count); * * This routine is called by the kernel to write a series of * characters to the tty device. The characters may come from * user space or kernel space. This routine will return the * number of characters actually accepted for writing. * * Optional: Required for writable devices. * * int (*put_char)(struct tty_struct *tty, unsigned char ch); * * This routine is called by the kernel to write a single * character to the tty device. If the kernel uses this routine, * it must call the flush_chars() routine (if defined) when it is * done stuffing characters into the driver. If there is no room * in the queue, the character is ignored. * * Optional: Kernel will use the write method if not provided. * * Note: Do not call this function directly, call tty_put_char * * void (*flush_chars)(struct tty_struct *tty); * * This routine is called by the kernel after it has written a * series of characters to the tty device using put_char(). * * Optional: * * Note: Do not call this function directly, call tty_driver_flush_chars * * int (*write_room)(struct tty_struct *tty); * * This routine returns the numbers of characters the tty driver * will accept for queuing to be written. This number is subject * to change as output buffers get emptied, or if the output flow * control is acted. * * Required if write method is provided else not needed. * * Note: Do not call this function directly, call tty_write_room * * int (*ioctl)(struct tty_struct *tty, struct file * file, * unsigned int cmd, unsigned long arg); * * This routine allows the tty driver to implement * device-specific ioctl's. If the ioctl number passed in cmd * is not recognized by the driver, it should return ENOIOCTLCMD. * * Optional * * long (*compat_ioctl)(struct tty_struct *tty, struct file * file, * unsigned int cmd, unsigned long arg); * * implement ioctl processing for 32 bit process on 64 bit system * * Optional * * void (*set_termios)(struct tty_struct *tty, struct ktermios * old); * * This routine allows the tty driver to be notified when * device's termios settings have changed. * * Optional: Called under the termios lock * * * void (*set_ldisc)(struct tty_struct *tty); * * This routine allows the tty driver to be notified when the * device's termios settings have changed. * * Optional: Called under BKL (currently) * * void (*throttle)(struct tty_struct * tty); * * This routine notifies the tty driver that input buffers for * the line discipline are close to full, and it should somehow * signal that no more characters should be sent to the tty. * * Optional: Always invoke via tty_throttle(); * * void (*unthrottle)(struct tty_struct * tty); * * This routine notifies the tty drivers that it should signals * that characters can now be sent to the tty without fear of * overrunning the input buffers of the line disciplines. * * Optional: Always invoke via tty_unthrottle(); * * void (*stop)(struct tty_struct *tty); * * This routine notifies the tty driver that it should stop * outputting characters to the tty device. * * Optional: * * Note: Call stop_tty not this method. * * void (*start)(struct tty_struct *tty); * * This routine notifies the tty driver that it resume sending * characters to the tty device. * * Optional: * * Note: Call start_tty not this method. * * void (*hangup)(struct tty_struct *tty); * * This routine notifies the tty driver that it should hangup the * tty device. * * Optional: * * int (*break_ctl)(struct tty_stuct *tty, int state); * * This optional routine requests the tty driver to turn on or * off BREAK status on the RS-232 port. If state is -1, * then the BREAK status should be turned on; if state is 0, then * BREAK should be turned off. * * If this routine is implemented, the high-level tty driver will * handle the following ioctls: TCSBRK, TCSBRKP, TIOCSBRK, * TIOCCBRK. * * If the driver sets TTY_DRIVER_HARDWARE_BREAK then the interface * will also be called with actual times and the hardware is expected * to do the delay work itself. 0 and -1 are still used for on/off. * * Optional: Required for TCSBRK/BRKP/etc handling. * * void (*wait_until_sent)(struct tty_struct *tty, int timeout); * * This routine waits until the device has written out all of the * characters in its transmitter FIFO. * * Optional: If not provided the device is assumed to have no FIFO * * Note: Usually correct to call tty_wait_until_sent * * void (*send_xchar)(struct tty_struct *tty, char ch); * * This routine is used to send a high-priority XON/XOFF * character to the device. * * Optional: If not provided then the write method is called under * the atomic write lock to keep it serialized with the ldisc. * * int (*resize)(struct tty_struct *tty, struct tty_struct *real_tty, * unsigned int rows, unsigned int cols); * * Called when a termios request is issued which changes the * requested terminal geometry. * * Optional: the default action is to update the termios structure * without error. This is usually the correct behaviour. Drivers should * not force errors here if they are not resizable objects (eg a serial * line). See tty_do_resize() if you need to wrap the standard method * in your own logic - the usual case. */ #include <linux/fs.h> #include <linux/list.h> #include <linux/cdev.h> struct tty_struct; struct tty_driver; struct tty_operations { int (*open)(struct tty_struct * tty, struct file * filp); void (*close)(struct tty_struct * tty, struct file * filp); int (*write)(struct tty_struct * tty, const unsigned char *buf, int count); int (*put_char)(struct tty_struct *tty, unsigned char ch); void (*flush_chars)(struct tty_struct *tty); int (*write_room)(struct tty_struct *tty); int (*chars_in_buffer)(struct tty_struct *tty); 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); void (*throttle)(struct tty_struct * tty); void (*unthrottle)(struct tty_struct * tty); void (*stop)(struct tty_struct *tty); void (*start)(struct tty_struct *tty); void (*hangup)(struct tty_struct *tty); int (*break_ctl)(struct tty_struct *tty, int state); void (*flush_buffer)(struct tty_struct *tty); void (*set_ldisc)(struct tty_struct *tty); void (*wait_until_sent)(struct tty_struct *tty, int timeout); void (*send_xchar)(struct tty_struct *tty, char ch); int (*read_proc)(char *page, char **start, off_t off, int count, int *eof, void *data); int (*tiocmget)(struct tty_struct *tty, struct file *file); int (*tiocmset)(struct tty_struct *tty, struct file *file, unsigned int set, unsigned int clear); int (*resize)(struct tty_struct *tty, struct tty_struct *real_tty, struct winsize *ws); #ifdef CONFIG_CONSOLE_POLL int (*poll_init)(struct tty_driver *driver, int line, char *options); int (*poll_get_char)(struct tty_driver *driver, int line); void (*poll_put_char)(struct tty_driver *driver, int line, char ch); #endif }; struct tty_driver { int magic; /* magic number for this structure */ struct cdev cdev; struct module *owner; const char *driver_name; const char *name; int name_base; /* offset of printed name */ int major; /* major device number */ int minor_start; /* start of minor device number */ int minor_num; /* number of *possible* devices */ int num; /* number of devices allocated */ short type; /* type of tty driver */ short subtype; /* subtype of tty driver */ struct ktermios init_termios; /* Initial termios */ int flags; /* tty driver flags */ int refcount; /* for loadable tty drivers */ struct proc_dir_entry *proc_entry; /* /proc fs entry */ struct tty_driver *other; /* only used for the PTY driver */ /* * Pointer to the tty data structures */ struct tty_struct **ttys; struct ktermios **termios; struct ktermios **termios_locked; void *driver_state; /* * Driver methods */ const struct tty_operations *ops; struct list_head tty_drivers; }; extern struct list_head tty_drivers; struct tty_driver *alloc_tty_driver(int lines); void put_tty_driver(struct tty_driver *driver); void tty_set_operations(struct tty_driver *driver, const struct tty_operations *op); extern struct tty_driver *tty_find_polling_driver(char *name, int *line); /* tty driver magic number */ #define TTY_DRIVER_MAGIC 0x5402 /* * tty driver flags * * TTY_DRIVER_RESET_TERMIOS --- requests the tty layer to reset the * termios setting when the last process has closed the device. * Used for PTY's, in particular. * * TTY_DRIVER_REAL_RAW --- if set, indicates that the driver will * guarantee never not to set any special character handling * flags if ((IGNBRK || (!BRKINT && !PARMRK)) && (IGNPAR || * !INPCK)). That is, if there is no reason for the driver to * send notifications of parity and break characters up to the * line driver, it won't do so. This allows the line driver to * optimize for this case if this flag is set. (Note that there * is also a promise, if the above case is true, not to signal * overruns, either.) * * TTY_DRIVER_DYNAMIC_DEV --- if set, the individual tty devices need * to be registered with a call to tty_register_driver() when the * device is found in the system and unregistered with a call to * tty_unregister_device() so the devices will be show up * properly in sysfs. If not set, driver->num entries will be * created by the tty core in sysfs when tty_register_driver() is * called. This is to be used by drivers that have tty devices * that can appear and disappear while the main tty driver is * registered with the tty core. * * TTY_DRIVER_DEVPTS_MEM -- don't use the standard arrays, instead * use dynamic memory keyed through the devpts filesystem. This * is only applicable to the pty driver. * * TTY_DRIVER_HARDWARE_BREAK -- hardware handles break signals. Pass * the requested timeout to the caller instead of using a simple * on/off interface. * */ #define TTY_DRIVER_INSTALLED 0x0001 #define TTY_DRIVER_RESET_TERMIOS 0x0002 #define TTY_DRIVER_REAL_RAW 0x0004 #define TTY_DRIVER_DYNAMIC_DEV 0x0008 #define TTY_DRIVER_DEVPTS_MEM 0x0010 #define TTY_DRIVER_HARDWARE_BREAK 0x0020 /* tty driver types */ #define TTY_DRIVER_TYPE_SYSTEM 0x0001 #define TTY_DRIVER_TYPE_CONSOLE 0x0002 #define TTY_DRIVER_TYPE_SERIAL 0x0003 #define TTY_DRIVER_TYPE_PTY 0x0004 #define TTY_DRIVER_TYPE_SCC 0x0005 /* scc driver */ #define TTY_DRIVER_TYPE_SYSCONS 0x0006 /* system subtypes (magic, used by tty_io.c) */ #define SYSTEM_TYPE_TTY 0x0001 #define SYSTEM_TYPE_CONSOLE 0x0002 #define SYSTEM_TYPE_SYSCONS 0x0003 #define SYSTEM_TYPE_SYSPTMX 0x0004 /* pty subtypes (magic, used by tty_io.c) */ #define PTY_TYPE_MASTER 0x0001 #define PTY_TYPE_SLAVE 0x0002 /* serial subtype definitions */ #define SERIAL_TYPE_NORMAL 1 |
