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  * struct tty_struct * (*lookup)(struct tty_driver *self, int idx)
  11  *
  12  *      Return the tty device corresponding to idx, NULL if there is not
  13  *      one currently in use and an ERR_PTR value on error. Called under
  14  *      tty_mutex (for now!)
  15  *
  16  *      Optional method. Default behaviour is to use the ttys array
  17  *
  18  * int (*install)(struct tty_driver *self, struct tty_struct *tty)
  19  *
  20  *      Install a new tty into the tty driver internal tables. Used in
  21  *      conjunction with lookup and remove methods.
  22  *
  23  *      Optional method. Default behaviour is to use the ttys array
  24  *
  25  * void (*remove)(struct tty_driver *self, struct tty_struct *tty)
  26  *
  27  *      Remove a closed tty from the tty driver internal tables. Used in
  28  *      conjunction with lookup and remove methods.
  29  *
  30  *      Optional method. Default behaviour is to use the ttys array
  31  *
  32  * int  (*open)(struct tty_struct * tty, struct file * filp);
  33  *
  34  *      This routine is called when a particular tty device is opened.
  35  *      This routine is mandatory; if this routine is not filled in,
  36  *      the attempted open will fail with ENODEV.
  37  *
  38  *      Required method.
  39  *
  40  * void (*close)(struct tty_struct * tty, struct file * filp);
  41  *
  42  *      This routine is called when a particular tty device is closed.
  43  *
  44  *      Required method.
  45  *
  46  * void (*shutdown)(struct tty_struct * tty);
  47  *
  48  *      This routine is called synchronously when a particular tty device
  49  *      is closed for the last time freeing up the resources.
  50  *
  51  *
  52  * void (*cleanup)(struct tty_struct * tty);
  53  *
  54  *      This routine is called asynchronously when a particular tty device
  55  *      is closed for the last time freeing up the resources. This is
  56  *      actually the second part of shutdown for routines that might sleep.
  57  *
  58  *
  59  * int (*write)(struct tty_struct * tty,
  60  *               const unsigned char *buf, int count);
  61  *
  62  *      This routine is called by the kernel to write a series of
  63  *      characters to the tty device.  The characters may come from
  64  *      user space or kernel space.  This routine will return the
  65  *      number of characters actually accepted for writing.
  66  *
  67  *      Optional: Required for writable devices.
  68  *
  69  * int (*put_char)(struct tty_struct *tty, unsigned char ch);
  70  *
  71  *      This routine is called by the kernel to write a single
  72  *      character to the tty device.  If the kernel uses this routine,
  73  *      it must call the flush_chars() routine (if defined) when it is
  74  *      done stuffing characters into the driver.  If there is no room
  75  *      in the queue, the character is ignored.
  76  *
  77  *      Optional: Kernel will use the write method if not provided.
  78  *
  79  *      Note: Do not call this function directly, call tty_put_char
  80  *
  81  * void (*flush_chars)(struct tty_struct *tty);
  82  *
  83  *      This routine is called by the kernel after it has written a
  84  *      series of characters to the tty device using put_char().
  85  *
  86  *      Optional:
  87  *
  88  *      Note: Do not call this function directly, call tty_driver_flush_chars
  89  *
  90  * int  (*write_room)(struct tty_struct *tty);
  91  *
  92  *      This routine returns the numbers of characters the tty driver
  93  *      will accept for queuing to be written.  This number is subject
  94  *      to change as output buffers get emptied, or if the output flow
  95  *      control is acted.
  96  *
  97  *      Required if write method is provided else not needed.
  98  *
  99  *      Note: Do not call this function directly, call tty_write_room
 100  *
 101  * int  (*ioctl)(struct tty_struct *tty, struct file * file,
 102  *          unsigned int cmd, unsigned long arg);
 103  *
 104  *      This routine allows the tty driver to implement
 105  *      device-specific ioctl's.  If the ioctl number passed in cmd
 106  *      is not recognized by the driver, it should return ENOIOCTLCMD.
 107  *
 108  *      Optional
 109  *
 110  * long (*compat_ioctl)(struct tty_struct *tty, struct file * file,
 111  *                      unsigned int cmd, unsigned long arg);
 112  *
 113  *      implement ioctl processing for 32 bit process on 64 bit system
 114  *
 115  *      Optional
 116  *
 117  * void (*set_termios)(struct tty_struct *tty, struct ktermios * old);
 118  *
 119  *      This routine allows the tty driver to be notified when
 120  *      device's termios settings have changed.
 121  *
 122  *      Optional: Called under the termios lock
 123  *
 124  *
 125  * void (*set_ldisc)(struct tty_struct *tty);
 126  *
 127  *      This routine allows the tty driver to be notified when the
 128  *      device's termios settings have changed.
 129  *
 130  *      Optional: Called under BKL (currently)
 131  *
 132  * void (*throttle)(struct tty_struct * tty);
 133  *
 134  *      This routine notifies the tty driver that input buffers for
 135  *      the line discipline are close to full, and it should somehow
 136  *      signal that no more characters should be sent to the tty.
 137  *
 138  *      Optional: Always invoke via tty_throttle(), called under the
 139  *      termios lock.
 140  *
 141  * void (*unthrottle)(struct tty_struct * tty);
 142  *
 143  *      This routine notifies the tty drivers that it should signals
 144  *      that characters can now be sent to the tty without fear of
 145  *      overrunning the input buffers of the line disciplines.
 146  *
 147  *      Optional: Always invoke via tty_unthrottle(), called under the
 148  *      termios lock.
 149  *
 150  * void (*stop)(struct tty_struct *tty);
 151  *
 152  *      This routine notifies the tty driver that it should stop
 153  *      outputting characters to the tty device.
 154  *
 155  *      Optional:
 156  *
 157  *      Note: Call stop_tty not this method.
 158  *
 159  * void (*start)(struct tty_struct *tty);
 160  *
 161  *      This routine notifies the tty driver that it resume sending
 162  *      characters to the tty device.
 163  *
 164  *      Optional:
 165  *
 166  *      Note: Call start_tty not this method.
 167  *
 168  * void (*hangup)(struct tty_struct *tty);
 169  *
 170  *      This routine notifies the tty driver that it should hangup the
 171  *      tty device.
 172  *
 173  *      Optional:
 174  *
 175  * int (*break_ctl)(struct tty_stuct *tty, int state);
 176  *
 177  *      This optional routine requests the tty driver to turn on or
 178  *      off BREAK status on the RS-232 port.  If state is -1,
 179  *      then the BREAK status should be turned on; if state is 0, then
 180  *      BREAK should be turned off.
 181  *
 182  *      If this routine is implemented, the high-level tty driver will
 183  *      handle the following ioctls: TCSBRK, TCSBRKP, TIOCSBRK,
 184  *      TIOCCBRK.
 185  *
 186  *      If the driver sets TTY_DRIVER_HARDWARE_BREAK then the interface
 187  *      will also be called with actual times and the hardware is expected
 188  *      to do the delay work itself. 0 and -1 are still used for on/off.
 189  *
 190  *      Optional: Required for TCSBRK/BRKP/etc handling.
 191  *
 192  * void (*wait_until_sent)(struct tty_struct *tty, int timeout);
 193  *
 194  *      This routine waits until the device has written out all of the
 195  *      characters in its transmitter FIFO.
 196  *
 197  *      Optional: If not provided the device is assumed to have no FIFO
 198  *
 199  *      Note: Usually correct to call tty_wait_until_sent
 200  *
 201  * void (*send_xchar)(struct tty_struct *tty, char ch);
 202  *
 203  *      This routine is used to send a high-priority XON/XOFF
 204  *      character to the device.
 205  *
 206  *      Optional: If not provided then the write method is called under
 207  *      the atomic write lock to keep it serialized with the ldisc.
 208  *
 209  * int (*resize)(struct tty_struct *tty, struct winsize *ws)
 210  *
 211  *      Called when a termios request is issued which changes the
 212  *      requested terminal geometry.
 213  *
 214  *      Optional: the default action is to update the termios structure
 215  *      without error. This is usually the correct behaviour. Drivers should
 216  *      not force errors here if they are not resizable objects (eg a serial
 217  *      line). See tty_do_resize() if you need to wrap the standard method
 218  *      in your own logic - the usual case.
 219  *
 220  * void (*set_termiox)(struct tty_struct *tty, struct termiox *new);
 221  *
 222  *      Called when the device receives a termiox based ioctl. Passes down
 223  *      the requested data from user space. This method will not be invoked
 224  *      unless the tty also has a valid tty->termiox pointer.
 225  *
 226  *      Optional: Called under the termios lock
 227  */
 228
 229 #include <linux/fs.h>
 230 #include <linux/list.h>
 231 #include <linux/cdev.h>
 232
 233 struct tty_struct;
 234 struct tty_driver;
 235
 236 struct tty_operations {
 237         struct tty_struct * (*lookup)(struct tty_driver *driver,
 238                         struct inode *inode, int idx);
 239         int  (*install)(struct tty_driver *driver, struct tty_struct *tty);
 240         void (*remove)(struct tty_driver *driver, struct tty_struct *tty);
 241         int  (*open)(struct tty_struct * tty, struct file * filp);
 242         void (*close)(struct tty_struct * tty, struct file * filp);
 243         void (*shutdown)(struct tty_struct *tty);
 244         void (*cleanup)(struct tty_struct *tty);
 245         int  (*write)(struct tty_struct * tty,
 246                       const unsigned char *buf, int count);
 247         int  (*put_char)(struct tty_struct *tty, unsigned char ch);
 248         void (*flush_chars)(struct tty_struct *tty);
 249         int  (*write_room)(struct tty_struct *tty);
 250         int  (*chars_in_buffer)(struct tty_struct *tty);
 251         int  (*ioctl)(struct tty_struct *tty, struct file * file,
 252                     unsigned int cmd, unsigned long arg);
 253         long (*compat_ioctl)(struct tty_struct *tty, struct file * file,
 254                              unsigned int cmd, unsigned long arg);
 255         void (*set_termios)(struct tty_struct *tty, struct ktermios * old);
 256         void (*throttle)(struct tty_struct * tty);
 257         void (*unthrottle)(struct tty_struct * tty);
 258         void (*stop)(struct tty_struct *tty);
 259         void (*start)(struct tty_struct *tty);
 260         void (*hangup)(struct tty_struct *tty);
 261         int (*break_ctl)(struct tty_struct *tty, int state);
 262         void (*flush_buffer)(struct tty_struct *tty);
 263         void (*set_ldisc)(struct tty_struct *tty);
 264         void (*wait_until_sent)(struct tty_struct *tty, int timeout);
 265         void (*send_xchar)(struct tty_struct *tty, char ch);
 266         int (*tiocmget)(struct tty_struct *tty, struct file *file);
 267         int (*tiocmset)(struct tty_struct *tty, struct file *file,
 268                         unsigned int set, unsigned int clear);
 269         int (*resize)(struct tty_struct *tty, struct winsize *ws);
 270         int (*set_termiox)(struct tty_struct *tty, struct termiox *tnew);
 271 #ifdef CONFIG_CONSOLE_POLL
 272         int (*poll_init)(struct tty_driver *driver, int line, char *options);
 273         int (*poll_get_char)(struct tty_driver *driver, int line);
 274         void (*poll_put_char)(struct tty_driver *driver, int line, char ch);
 275 #endif
 276         const struct file_operations *proc_fops;
 277 };
 278
 279 struct tty_driver {
 280         int     magic;          /* magic number for this structure */
 281         struct kref kref;       /* Reference management */
 282         struct cdev cdev;
 283         struct module   *owner;
 284         const char      *driver_name;
 285         const char      *name;
 286         int     name_base;      /* offset of printed name */
 287         int     major;          /* major device number */
 288         int     minor_start;    /* start of minor device number */
 289         int     minor_num;      /* number of *possible* devices */
 290         int     num;            /* number of devices allocated */
 291         short   type;           /* type of tty driver */
 292         short   subtype;        /* subtype of tty driver */
 293         struct ktermios init_termios; /* Initial termios */
 294         int     flags;          /* tty driver flags */
 295         struct proc_dir_entry *proc_entry; /* /proc fs entry */
 296         struct tty_driver *other; /* only used for the PTY driver */
 297
 298         /*
 299          * Pointer to the tty data structures
 300          */
 301         struct tty_struct **ttys;
 302         struct ktermios **termios;
 303         struct ktermios **termios_locked;
 304         void *driver_state;
 305
 306         /*
 307          * Driver methods
 308          */
 309
 310         const struct tty_operations *ops;
 311         struct list_head tty_drivers;
 312 };
 313
 314 extern struct list_head tty_drivers;
 315
 316 extern struct tty_driver *alloc_tty_driver(int lines);
 317 extern void put_tty_driver(struct tty_driver *driver);
 318 extern void tty_set_operations(struct tty_driver *driver,
 319                         const struct tty_operations *op);
 320 extern struct tty_driver *tty_find_polling_driver(char *name, int *line);
 321
 322 extern void tty_driver_kref_put(struct tty_driver *driver);
 323
 324 static inline struct tty_driver *tty_driver_kref_get(struct tty_driver *d)
 325 {
 326         kref_get(&d->kref);
 327         return d;
 328 }
 329
 330 /* tty driver magic number */
 331 #define TTY_DRIVER_MAGIC                0x5402
 332
 333 /*
 334  * tty driver flags
 335  *
 336  * TTY_DRIVER_RESET_TERMIOS --- requests the tty layer to reset the
 337  *      termios setting when the last process has closed the device.
 338  *      Used for PTY's, in particular.
 339  *
 340  * TTY_DRIVER_REAL_RAW --- if set, indicates that the driver will
 341  *      guarantee never not to set any special character handling
 342  *      flags if ((IGNBRK || (!BRKINT && !PARMRK)) && (IGNPAR ||
 343  *      !INPCK)).  That is, if there is no reason for the driver to
 344  *      send notifications of parity and break characters up to the
 345  *      line driver, it won't do so.  This allows the line driver to
 346  *      optimize for this case if this flag is set.  (Note that there
 347  *      is also a promise, if the above case is true, not to signal
 348  *      overruns, either.)
 349  *
 350  * TTY_DRIVER_DYNAMIC_DEV --- if set, the individual tty devices need
 351  *      to be registered with a call to tty_register_driver() when the
 352  *      device is found in the system and unregistered with a call to
 353  *      tty_unregister_device() so the devices will be show up
 354  *      properly in sysfs.  If not set, driver->num entries will be
 355  *      created by the tty core in sysfs when tty_register_driver() is
 356  *      called.  This is to be used by drivers that have tty devices
 357  *      that can appear and disappear while the main tty driver is
 358  *      registered with the tty core.
 359  *
 360  * TTY_DRIVER_DEVPTS_MEM -- don't use the standard arrays, instead
 361  *      use dynamic memory keyed through the devpts filesystem.  This
 362  *      is only applicable to the pty driver.
 363  *
 364  * TTY_DRIVER_HARDWARE_BREAK -- hardware handles break signals. Pass
 365  *      the requested timeout to the caller instead of using a simple
 366  *      on/off interface.
 367  *
 368  */
 369 #define TTY_DRIVER_INSTALLED            0x0001
 370 #define TTY_DRIVER_RESET_TERMIOS        0x0002
 371 #define TTY_DRIVER_REAL_RAW             0x0004
 372 #define TTY_DRIVER_DYNAMIC_DEV          0x0008
 373 #define TTY_DRIVER_DEVPTS_MEM           0x0010
 374 #define TTY_DRIVER_HARDWARE_BREAK       0x0020
 375
 376 /* tty driver types */
 377 #define TTY_DRIVER_TYPE_SYSTEM          0x0001
 378 #define TTY_DRIVER_TYPE_CONSOLE         0x0002
 379 #define TTY_DRIVER_TYPE_SERIAL          0x0003
 380 #define TTY_DRIVER_TYPE_PTY             0x0004
 381 #define TTY_DRIVER_TYPE_SCC             0x0005  /* scc driver */
 382 #define TTY_DRIVER_TYPE_SYSCONS         0x0006
 383
 384 /* system subtypes (magic, used by tty_io.c) */
 385 #define SYSTEM_TYPE_TTY                 0x0001
 386 #define SYSTEM_TYPE_CONSOLE             0x0002
 387 #define SYSTEM_TYPE_SYSCONS             0x0003
 388 #define SYSTEM_TYPE_SYSPTMX             0x0004
 389
 390 /* pty subtypes (magic, used by tty_io.c) */
 391 #define PTY_TYPE_MASTER                 0x0001
 392 #define PTY_TYPE_SLAVE                  0x0002
 393
 394 /* serial subtype definitions */
 395 #define SERIAL_TYPE_NORMAL      1
 396
 397 #endif /* #ifdef _LINUX_TTY_DRIVER_H */