include/linux/tty_driver.h

   1 #ifndef _LINUX_TTY_DRIVER_H
   2 #define _LINUX_TTY_DRIVER_H
   3
   4 /*
   5  * This structure defines the interface between the low-level tty
   6  * driver and the tty routines.  The following routines can be
   7  * defined; unless noted otherwise, they are optional, and can be
   8  * filled in with a null pointer.
   9  *
  10  * int  (*open)(struct tty_struct * tty, struct file * filp);
  11  *
  12  *      This routine is called when a particular tty device is opened.
  13  *      This routine is mandatory; if this routine is not filled in,
  14  *      the attempted open will fail with ENODEV.
  15  *
  16  * void (*close)(struct tty_struct * tty, struct file * filp);
  17  *
  18  *      This routine is called when a particular tty device is closed.
  19  *
  20  * int (*write)(struct tty_struct * tty, int from_user,
  21  *               const unsigned char *buf, int count);
  22  *
  23  *      This routine is called by the kernel to write a series of
  24  *      characters to the tty device.  The characters may come from
  25  *      user space or kernel space.  This routine will return the
  26  *      number of characters actually accepted for writing.  This
  27  *      routine is mandatory.
  28  *
  29  * void (*put_char)(struct tty_struct *tty, unsigned char ch);
  30  *
  31  *      This routine is called by the kernel to write a single
  32  *      character to the tty device.  If the kernel uses this routine,
  33  *      it must call the flush_chars() routine (if defined) when it is
  34  *      done stuffing characters into the driver.  If there is no room
  35  *      in the queue, the character is ignored.
  36  *
  37  * void (*flush_chars)(struct tty_struct *tty);
  38  *
  39  *      This routine is called by the kernel after it has written a
  40  *      series of characters to the tty device using put_char().
  41  *
  42  * int  (*write_room)(struct tty_struct *tty);
  43  *
  44  *      This routine returns the numbers of characters the tty driver
  45  *      will accept for queuing to be written.  This number is subject
  46  *      to change as output buffers get emptied, or if the output flow
  47  *      control is acted.
  48  *
  49  * int  (*ioctl)(struct tty_struct *tty, struct file * file,
  50  *          unsigned int cmd, unsigned long arg);
  51  *
  52  *      This routine allows the tty driver to implement
  53  *      device-specific ioctl's.  If the ioctl number passed in cmd
  54  *      is not recognized by the driver, it should return ENOIOCTLCMD.
  55  *
  56  * void (*set_termios)(struct tty_struct *tty, struct termios * old);
  57  *
  58  *      This routine allows the tty driver to be notified when
  59  *      device's termios settings have changed.  Note that a
  60  *      well-designed tty driver should be prepared to accept the case
  61  *      where old == NULL, and try to do something rational.
  62  *
  63  * void (*set_ldisc)(struct tty_struct *tty);
  64  *
  65  *      This routine allows the tty driver to be notified when the
  66  *      device's termios settings have changed.
  67  *
  68  * void (*throttle)(struct tty_struct * tty);
  69  *
  70  *      This routine notifies the tty driver that input buffers for
  71  *      the line discipline are close to full, and it should somehow
  72  *      signal that no more characters should be sent to the tty.
  73  *
  74  * void (*unthrottle)(struct tty_struct * tty);
  75  *
  76  *      This routine notifies the tty drivers that it should signals
  77  *      that characters can now be sent to the tty without fear of
  78  *      overrunning the input buffers of the line disciplines.
  79  *
  80  * void (*stop)(struct tty_struct *tty);
  81  *
  82  *      This routine notifies the tty driver that it should stop
  83  *      outputting characters to the tty device.
  84  *
  85  * void (*start)(struct tty_struct *tty);
  86  *
  87  *      This routine notifies the tty driver that it resume sending
  88  *      characters to the tty device.
  89  *
  90  * void (*hangup)(struct tty_struct *tty);
  91  *
  92  *      This routine notifies the tty driver that it should hangup the
  93  *      tty device.
  94  *
  95  * void (*break_ctl)(struct tty_stuct *tty, int state);
  96  *
  97  *      This optional routine requests the tty driver to turn on or
  98  *      off BREAK status on the RS-232 port.  If state is -1,
  99  *      then the BREAK status should be turned on; if state is 0, then
 100  *      BREAK should be turned off.
 101  *
 102  *      If this routine is implemented, the high-level tty driver will
 103  *      handle the following ioctls: TCSBRK, TCSBRKP, TIOCSBRK,
 104  *      TIOCCBRK.  Otherwise, these ioctls will be passed down to the
 105  *      driver to handle.
 106  *
 107  * void (*wait_until_sent)(struct tty_struct *tty, int timeout);
 108  *
 109  *      This routine waits until the device has written out all of the
 110  *      characters in its transmitter FIFO.
 111  *
 112  * void (*send_xchar)(struct tty_struct *tty, char ch);
 113  *
 114  *      This routine is used to send a high-priority XON/XOFF
 115  *      character to the device.
 116  */
 117
 118 #include <linux/fs.h>
 119
 120 struct tty_driver {
 121         int     magic;          /* magic number for this structure */
 122         const char      *driver_name;
 123         const char      *name;
 124         int     name_base;      /* offset of printed name */
 125         short   major;          /* major device number */
 126         short   minor_start;    /* start of minor device number*/
 127         short   num;            /* number of devices */
 128         short   type;           /* type of tty driver */
 129         short   subtype;        /* subtype of tty driver */
 130         struct termios init_termios; /* Initial termios */
 131         int     flags;          /* tty driver flags */
 132         int     *refcount;      /* for loadable tty drivers */
 133         struct proc_dir_entry *proc_entry; /* /proc fs entry */
 134         struct tty_driver *other; /* only used for the PTY driver */
 135
 136         /*
 137          * Pointer to the tty data structures
 138          */
 139         struct tty_struct **table;
 140         struct termios **termios;
 141         struct termios **termios_locked;
 142         void *driver_state;     /* only used for the PTY driver */
 143
 144         /*
 145          * Interface routines from the upper tty layer to the tty
 146          * driver.
 147          */
 148         int  (*open)(struct tty_struct * tty, struct file * filp);
 149         void (*close)(struct tty_struct * tty, struct file * filp);
 150         int  (*write)(struct tty_struct * tty, int from_user,
 151                       const unsigned char *buf, int count);
 152         void (*put_char)(struct tty_struct *tty, unsigned char ch);
 153         void (*flush_chars)(struct tty_struct *tty);
 154         int  (*write_room)(struct tty_struct *tty);
 155         int  (*chars_in_buffer)(struct tty_struct *tty);
 156         int  (*ioctl)(struct tty_struct *tty, struct file * file,
 157                     unsigned int cmd, unsigned long arg);
 158         void (*set_termios)(struct tty_struct *tty, struct termios * old);
 159         void (*throttle)(struct tty_struct * tty);
 160         void (*unthrottle)(struct tty_struct * tty);
 161         void (*stop)(struct tty_struct *tty);
 162         void (*start)(struct tty_struct *tty);
 163         void (*hangup)(struct tty_struct *tty);
 164         void (*break_ctl)(struct tty_struct *tty, int state);
 165         void (*flush_buffer)(struct tty_struct *tty);
 166         void (*set_ldisc)(struct tty_struct *tty);
 167         void (*wait_until_sent)(struct tty_struct *tty, int timeout);
 168         void (*send_xchar)(struct tty_struct *tty, char ch);
 169         int (*read_proc)(char *page, char **start, off_t off,
 170                           int count, int *eof, void *data);
 171         int (*write_proc)(struct file *file, const char *buffer,
 172                           unsigned long count, void *data);
 173
 174         /*
 175          * linked list pointers
 176          */
 177         struct tty_driver *next;
 178         struct tty_driver *prev;
 179 };
 180
 181 /* tty driver magic number */
 182 #define TTY_DRIVER_MAGIC                0x5402
 183
 184 /*
 185  * tty driver flags
 186  *
 187  * TTY_DRIVER_RESET_TERMIOS --- requests the tty layer to reset the
 188  *      termios setting when the last process has closed the device.
 189  *      Used for PTY's, in particular.
 190  *
 191  * TTY_DRIVER_REAL_RAW --- if set, indicates that the driver will
 192  *      guarantee never not to set any special character handling
 193  *      flags if ((IGNBRK || (!BRKINT && !PARMRK)) && (IGNPAR ||
 194  *      !INPCK)).  That is, if there is no reason for the driver to
 195  *      send notifications of parity and break characters up to the
 196  *      line driver, it won't do so.  This allows the line driver to
 197  *      optimize for this case if this flag is set.  (Note that there
 198  *      is also a promise, if the above case is true, not to signal
 199  *      overruns, either.)
 200  *
 201  * TTY_DRIVER_NO_DEVFS --- if set, do not create devfs entries. This
 202  *      is only used by tty_register_driver().
 203  *
 204  */
 205 #define TTY_DRIVER_INSTALLED            0x0001
 206 #define TTY_DRIVER_RESET_TERMIOS        0x0002
 207 #define TTY_DRIVER_REAL_RAW             0x0004
 208 #define TTY_DRIVER_NO_DEVFS             0x0008
 209
 210 /* tty driver types */
 211 #define TTY_DRIVER_TYPE_SYSTEM          0x0001
 212 #define TTY_DRIVER_TYPE_CONSOLE         0x0002
 213 #define TTY_DRIVER_TYPE_SERIAL          0x0003
 214 #define TTY_DRIVER_TYPE_PTY             0x0004
 215 #define TTY_DRIVER_TYPE_SCC             0x0005  /* scc driver */
 216 #define TTY_DRIVER_TYPE_SYSCONS         0x0006
 217
 218 /* system subtypes (magic, used by tty_io.c) */
 219 #define SYSTEM_TYPE_TTY                 0x0001
 220 #define SYSTEM_TYPE_CONSOLE             0x0002
 221 #define SYSTEM_TYPE_SYSCONS             0x0003
 222 #define SYSTEM_TYPE_SYSPTMX             0x0004
 223
 224 /* pty subtypes (magic, used by tty_io.c) */
 225 #define PTY_TYPE_MASTER                 0x0001
 226 #define PTY_TYPE_SLAVE                  0x0002
 227
 228 /* serial subtype definitions */
 229 #define SERIAL_TYPE_NORMAL      1
 230 #define SERIAL_TYPE_CALLOUT     2
 231
 232 #endif /* #ifdef _LINUX_TTY_DRIVER_H */