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,
  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 #include <linux/list.h>
 120 #include <linux/cdev.h>
 121
 122 struct tty_struct;
 123
 124 struct tty_operations {
 125         int  (*open)(struct tty_struct * tty, struct file * filp);
 126         void (*close)(struct tty_struct * tty, struct file * filp);
 127         int  (*write)(struct tty_struct * tty,
 128                       const unsigned char *buf, int count);
 129         void (*put_char)(struct tty_struct *tty, unsigned char ch);
 130         void (*flush_chars)(struct tty_struct *tty);
 131         int  (*write_room)(struct tty_struct *tty);
 132         int  (*chars_in_buffer)(struct tty_struct *tty);
 133         int  (*ioctl)(struct tty_struct *tty, struct file * file,
 134                     unsigned int cmd, unsigned long arg);
 135         void (*set_termios)(struct tty_struct *tty, struct termios * old);
 136         void (*throttle)(struct tty_struct * tty);
 137         void (*unthrottle)(struct tty_struct * tty);
 138         void (*stop)(struct tty_struct *tty);
 139         void (*start)(struct tty_struct *tty);
 140         void (*hangup)(struct tty_struct *tty);
 141         void (*break_ctl)(struct tty_struct *tty, int state);
 142         void (*flush_buffer)(struct tty_struct *tty);
 143         void (*set_ldisc)(struct tty_struct *tty);
 144         void (*wait_until_sent)(struct tty_struct *tty, int timeout);
 145         void (*send_xchar)(struct tty_struct *tty, char ch);
 146         int (*read_proc)(char *page, char **start, off_t off,
 147                           int count, int *eof, void *data);
 148         int (*write_proc)(struct file *file, const char __user *buffer,
 149                           unsigned long count, void *data);
 150         int (*tiocmget)(struct tty_struct *tty, struct file *file);
 151         int (*tiocmset)(struct tty_struct *tty, struct file *file,
 152                         unsigned int set, unsigned int clear);
 153 };
 154
 155 struct tty_driver {
 156         int     magic;          /* magic number for this structure */
 157         struct cdev cdev;
 158         struct module   *owner;
 159         const char      *driver_name;
 160         const char      *devfs_name;
 161         const char      *name;
 162         int     name_base;      /* offset of printed name */
 163         int     major;          /* major device number */
 164         int     minor_start;    /* start of minor device number */
 165         int     minor_num;      /* number of *possible* devices */
 166         int     num;            /* number of devices allocated */
 167         short   type;           /* type of tty driver */
 168         short   subtype;        /* subtype of tty driver */
 169         struct termios init_termios; /* Initial termios */
 170         int     flags;          /* tty driver flags */
 171         int     refcount;       /* for loadable tty drivers */
 172         struct proc_dir_entry *proc_entry; /* /proc fs entry */
 173         struct tty_driver *other; /* only used for the PTY driver */
 174
 175         /*
 176          * Pointer to the tty data structures
 177          */
 178         struct tty_struct **ttys;
 179         struct termios **termios;
 180         struct termios **termios_locked;
 181         void *driver_state;     /* only used for the PTY driver */
 182
 183         /*
 184          * Interface routines from the upper tty layer to the tty
 185          * driver.      Will be replaced with struct tty_operations.
 186          */
 187         int  (*open)(struct tty_struct * tty, struct file * filp);
 188         void (*close)(struct tty_struct * tty, struct file * filp);
 189         int  (*write)(struct tty_struct * tty,
 190                       const unsigned char *buf, int count);
 191         void (*put_char)(struct tty_struct *tty, unsigned char ch);
 192         void (*flush_chars)(struct tty_struct *tty);
 193         int  (*write_room)(struct tty_struct *tty);
 194         int  (*chars_in_buffer)(struct tty_struct *tty);
 195         int  (*ioctl)(struct tty_struct *tty, struct file * file,
 196                     unsigned int cmd, unsigned long arg);
 197         void (*set_termios)(struct tty_struct *tty, struct termios * old);
 198         void (*throttle)(struct tty_struct * tty);
 199         void (*unthrottle)(struct tty_struct * tty);
 200         void (*stop)(struct tty_struct *tty);
 201         void (*start)(struct tty_struct *tty);
 202         void (*hangup)(struct tty_struct *tty);
 203         void (*break_ctl)(struct tty_struct *tty, int state);
 204         void (*flush_buffer)(struct tty_struct *tty);
 205         void (*set_ldisc)(struct tty_struct *tty);
 206         void (*wait_until_sent)(struct tty_struct *tty, int timeout);
 207         void (*send_xchar)(struct tty_struct *tty, char ch);
 208         int (*read_proc)(char *page, char **start, off_t off,
 209                           int count, int *eof, void *data);
 210         int (*write_proc)(struct file *file, const char __user *buffer,
 211                           unsigned long count, void *data);
 212         int (*tiocmget)(struct tty_struct *tty, struct file *file);
 213         int (*tiocmset)(struct tty_struct *tty, struct file *file,
 214                         unsigned int set, unsigned int clear);
 215
 216         struct list_head tty_drivers;
 217 };
 218
 219 extern struct list_head tty_drivers;
 220
 221 struct tty_driver *alloc_tty_driver(int lines);
 222 void put_tty_driver(struct tty_driver *driver);
 223 void tty_set_operations(struct tty_driver *driver, struct tty_operations *op);
 224
 225 /* tty driver magic number */
 226 #define TTY_DRIVER_MAGIC                0x5402
 227
 228 /*
 229  * tty driver flags
 230  *
 231  * TTY_DRIVER_RESET_TERMIOS --- requests the tty layer to reset the
 232  *      termios setting when the last process has closed the device.
 233  *      Used for PTY's, in particular.
 234  *
 235  * TTY_DRIVER_REAL_RAW --- if set, indicates that the driver will
 236  *      guarantee never not to set any special character handling
 237  *      flags if ((IGNBRK || (!BRKINT && !PARMRK)) && (IGNPAR ||
 238  *      !INPCK)).  That is, if there is no reason for the driver to
 239  *      send notifications of parity and break characters up to the
 240  *      line driver, it won't do so.  This allows the line driver to
 241  *      optimize for this case if this flag is set.  (Note that there
 242  *      is also a promise, if the above case is true, not to signal
 243  *      overruns, either.)
 244  *
 245  * TTY_DRIVER_NO_DEVFS --- if set, do not create devfs entries. This
 246  *      is only used by tty_register_driver().
 247  *
 248  * TTY_DRIVER_DEVPTS_MEM -- don't use the standard arrays, instead
 249  *      use dynamic memory keyed through the devpts filesystem.  This
 250  *      is only applicable to the pty driver.
 251  */
 252 #define TTY_DRIVER_INSTALLED            0x0001
 253 #define TTY_DRIVER_RESET_TERMIOS        0x0002
 254 #define TTY_DRIVER_REAL_RAW             0x0004
 255 #define TTY_DRIVER_NO_DEVFS             0x0008
 256 #define TTY_DRIVER_DEVPTS_MEM           0x0010
 257
 258 /* tty driver types */
 259 #define TTY_DRIVER_TYPE_SYSTEM          0x0001
 260 #define TTY_DRIVER_TYPE_CONSOLE         0x0002
 261 #define TTY_DRIVER_TYPE_SERIAL          0x0003
 262 #define TTY_DRIVER_TYPE_PTY             0x0004
 263 #define TTY_DRIVER_TYPE_SCC             0x0005  /* scc driver */
 264 #define TTY_DRIVER_TYPE_SYSCONS         0x0006
 265
 266 /* system subtypes (magic, used by tty_io.c) */
 267 #define SYSTEM_TYPE_TTY                 0x0001
 268 #define SYSTEM_TYPE_CONSOLE             0x0002
 269 #define SYSTEM_TYPE_SYSCONS             0x0003
 270 #define SYSTEM_TYPE_SYSPTMX             0x0004
 271
 272 /* pty subtypes (magic, used by tty_io.c) */
 273 #define PTY_TYPE_MASTER                 0x0001
 274 #define PTY_TYPE_SLAVE                  0x0002
 275
 276 /* serial subtype definitions */
 277 #define SERIAL_TYPE_NORMAL      1
 278
 279 #endif /* #ifdef _LINUX_TTY_DRIVER_H */