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  *      Note that tty_shutdown() is not called if ops->shutdown is defined.
  51  *      This means one is responsible to take care of calling ops->remove (e.g.
  52  *      via tty_driver_remove_tty) and releasing tty->termios.
  53  *
  54  *
  55  * void (*cleanup)(struct tty_struct * tty);
  56  *
  57  *      This routine is called asynchronously when a particular tty device
  58  *      is closed for the last time freeing up the resources. This is
  59  *      actually the second part of shutdown for routines that might sleep.
  60  *
  61  *
  62  * int (*write)(struct tty_struct * tty,
  63  *               const unsigned char *buf, int count);
  64  *
  65  *      This routine is called by the kernel to write a series of
  66  *      characters to the tty device.  The characters may come from
  67  *      user space or kernel space.  This routine will return the
  68  *      number of characters actually accepted for writing.
  69  *
  70  *      Optional: Required for writable devices.
  71  *
  72  * int (*put_char)(struct tty_struct *tty, unsigned char ch);
  73  *
  74  *      This routine is called by the kernel to write a single
  75  *      character to the tty device.  If the kernel uses this routine,
  76  *      it must call the flush_chars() routine (if defined) when it is
  77  *      done stuffing characters into the driver.  If there is no room
  78  *      in the queue, the character is ignored.
  79  *
  80  *      Optional: Kernel will use the write method if not provided.
  81  *
  82  *      Note: Do not call this function directly, call tty_put_char
  83  *
  84  * void (*flush_chars)(struct tty_struct *tty);
  85  *
  86  *      This routine is called by the kernel after it has written a
  87  *      series of characters to the tty device using put_char().
  88  *
  89  *      Optional:
  90  *
  91  *      Note: Do not call this function directly, call tty_driver_flush_chars
  92  *
  93  * int  (*write_room)(struct tty_struct *tty);
  94  *
  95  *      This routine returns the numbers of characters the tty driver
  96  *      will accept for queuing to be written.  This number is subject
  97  *      to change as output buffers get emptied, or if the output flow
  98  *      control is acted.
  99  *
 100  *      Required if write method is provided else not needed.
 101  *
 102  *      Note: Do not call this function directly, call tty_write_room
 103  *
 104  * int  (*ioctl)(struct tty_struct *tty, unsigned int cmd, unsigned long arg);
 105  *
 106  *      This routine allows the tty driver to implement
 107  *      device-specific ioctls.  If the ioctl number passed in cmd
 108  *      is not recognized by the driver, it should return ENOIOCTLCMD.
 109  *
 110  *      Optional
 111  *
 112  * long (*compat_ioctl)(struct tty_struct *tty,,
 113  *                      unsigned int cmd, unsigned long arg);
 114  *
 115  *      implement ioctl processing for 32 bit process on 64 bit system
 116  *
 117  *      Optional
 118  *
 119  * void (*set_termios)(struct tty_struct *tty, struct ktermios * old);
 120  *
 121  *      This routine allows the tty driver to be notified when
 122  *      device's termios settings have changed.
 123  *
 124  *      Optional: Called under the termios lock
 125  *
 126  *
 127  * void (*set_ldisc)(struct tty_struct *tty);
 128  *
 129  *      This routine allows the tty driver to be notified when the
 130  *      device's termios settings have changed.
 131  *
 132  *      Optional: Called under BKL (currently)
 133  *
 134  * void (*throttle)(struct tty_struct * tty);
 135  *
 136  *      This routine notifies the tty driver that input buffers for
 137  *      the line discipline are close to full, and it should somehow
 138  *      signal that no more characters should be sent to the tty.
 139  *
 140  *      Optional: Always invoke via tty_throttle(), called under the
 141  *      termios lock.
 142  *
 143  * void (*unthrottle)(struct tty_struct * tty);
 144  *
 145  *      This routine notifies the tty drivers that it should signals
 146  *      that characters can now be sent to the tty without fear of
 147  *      overrunning the input buffers of the line disciplines.
 148  *
 149  *      Optional: Always invoke via tty_unthrottle(), called under the
 150  *      termios lock.
 151  *
 152  * void (*stop)(struct tty_struct *tty);
 153  *
 154  *      This routine notifies the tty driver that it should stop
 155  *      outputting characters to the tty device.
 156  *
 157  *      Optional:
 158  *
 159  *      Note: Call stop_tty not this method.
 160  *
 161  * void (*start)(struct tty_struct *tty);
 162  *
 163  *      This routine notifies the tty driver that it resume sending
 164  *      characters to the tty device.
 165  *
 166  *      Optional:
 167  *
 168  *      Note: Call start_tty not this method.
 169  *
 170  * void (*hangup)(struct tty_struct *tty);
 171  *
 172  *      This routine notifies the tty driver that it should hang up the
 173  *      tty device.
 174  *
 175  *      Optional:
 176  *
 177  * int (*break_ctl)(struct tty_struct *tty, int state);
 178  *
 179  *      This optional routine requests the tty driver to turn on or
 180  *      off BREAK status on the RS-232 port.  If state is -1,
 181  *      then the BREAK status should be turned on; if state is 0, then
 182  *      BREAK should be turned off.
 183  *
 184  *      If this routine is implemented, the high-level tty driver will
 185  *      handle the following ioctls: TCSBRK, TCSBRKP, TIOCSBRK,
 186  *      TIOCCBRK.
 187  *
 188  *      If the driver sets TTY_DRIVER_HARDWARE_BREAK then the interface
 189  *      will also be called with actual times and the hardware is expected
 190  *      to do the delay work itself. 0 and -1 are still used for on/off.
 191  *
 192  *      Optional: Required for TCSBRK/BRKP/etc handling.
 193  *
 194  * void (*wait_until_sent)(struct tty_struct *tty, int timeout);
 195  *
 196  *      This routine waits until the device has written out all of the
 197  *      characters in its transmitter FIFO.
 198  *
 199  *      Optional: If not provided the device is assumed to have no FIFO
 200  *
 201  *      Note: Usually correct to call tty_wait_until_sent
 202  *
 203  * void (*send_xchar)(struct tty_struct *tty, char ch);
 204  *
 205  *      This routine is used to send a high-priority XON/XOFF
 206  *      character to the device.
 207  *
 208  *      Optional: If not provided then the write method is called under
 209  *      the atomic write lock to keep it serialized with the ldisc.
 210  *
 211  * int (*resize)(struct tty_struct *tty, struct winsize *ws)
 212  *
 213  *      Called when a termios request is issued which changes the
 214  *      requested terminal geometry.
 215  *
 216  *      Optional: the default action is to update the termios structure
 217  *      without error. This is usually the correct behaviour. Drivers should
 218  *      not force errors here if they are not resizable objects (eg a serial
 219  *      line). See tty_do_resize() if you need to wrap the standard method
 220  *      in your own logic - the usual case.
 221  *
 222  * void (*set_termiox)(struct tty_struct *tty, struct termiox *new);
 223  *
 224  *      Called when the device receives a termiox based ioctl. Passes down
 225  *      the requested data from user space. This method will not be invoked
 226  *      unless the tty also has a valid tty->termiox pointer.
 227  *
 228  *      Optional: Called under the termios lock
 229  *
 230  * int (*get_icount)(struct tty_struct *tty, struct serial_icounter *icount);
 231  *
 232  *      Called when the device receives a TIOCGICOUNT ioctl. Passed a kernel
 233  *      structure to complete. This method is optional and will only be called
 234  *      if provided (otherwise EINVAL will be returned).
 235  */
 236
 237 #include <linux/fs.h>
 238 #include <linux/list.h>
 239 #include <linux/cdev.h>
 240 #include <linux/termios.h>
 241
 242 struct tty_struct;
 243 struct tty_driver;
 244 struct serial_icounter_struct;
 245
 246 struct tty_operations {
 247         struct tty_struct * (*lookup)(struct tty_driver *driver,
 248                         struct inode *inode, int idx);
 249         int  (*install)(struct tty_driver *driver, struct tty_struct *tty);
 250         void (*remove)(struct tty_driver *driver, struct tty_struct *tty);
 251         int  (*open)(struct tty_struct * tty, struct file * filp);
 252         void (*close)(struct tty_struct * tty, struct file * filp);
 253         void (*shutdown)(struct tty_struct *tty);
 254         void (*cleanup)(struct tty_struct *tty);
 255         int  (*write)(struct tty_struct * tty,
 256                       const unsigned char *buf, int count);
 257         int  (*put_char)(struct tty_struct *tty, unsigned char ch);
 258         void (*flush_chars)(struct tty_struct *tty);
 259         int  (*write_room)(struct tty_struct *tty);
 260         int  (*chars_in_buffer)(struct tty_struct *tty);
 261         int  (*ioctl)(struct tty_struct *tty,
 262                     unsigned int cmd, unsigned long arg);
 263         long (*compat_ioctl)(struct tty_struct *tty,
 264                              unsigned int cmd, unsigned long arg);
 265         void (*set_termios)(struct tty_struct *tty, struct ktermios * old);
 266         void (*throttle)(struct tty_struct * tty);
 267         void (*unthrottle)(struct tty_struct * tty);
 268         void (*stop)(struct tty_struct *tty);
 269         void (*start)(struct tty_struct *tty);
 270         void (*hangup)(struct tty_struct *tty);
 271         int (*break_ctl)(struct tty_struct *tty, int state);
 272         void (*flush_buffer)(struct tty_struct *tty);
 273         void (*set_ldisc)(struct tty_struct *tty);
 274         void (*wait_until_sent)(struct tty_struct *tty, int timeout);
 275         void (*send_xchar)(struct tty_struct *tty, char ch);
 276         int (*tiocmget)(struct tty_struct *tty);
 277         int (*tiocmset)(struct tty_struct *tty,
 278                         unsigned int set, unsigned int clear);
 279         int (*resize)(struct tty_struct *tty, struct winsize *ws);
 280         int (*set_termiox)(struct tty_struct *tty, struct termiox *tnew);
 281         int (*get_icount)(struct tty_struct *tty,
 282                                 struct serial_icounter_struct *icount);
 283 #ifdef CONFIG_CONSOLE_POLL
 284         int (*poll_init)(struct tty_driver *driver, int line, char *options);
 285         int (*poll_get_char)(struct tty_driver *driver, int line);
 286         void (*poll_put_char)(struct tty_driver *driver, int line, char ch);
 287 #endif
 288         const struct file_operations *proc_fops;
 289 };
 290
 291 struct tty_driver {
 292         int     magic;          /* magic number for this structure */
 293         struct kref kref;       /* Reference management */
 294         struct cdev cdev;
 295         struct module   *owner;
 296         const char      *driver_name;
 297         const char      *name;
 298         int     name_base;      /* offset of printed name */
 299         int     major;          /* major device number */
 300         int     minor_start;    /* start of minor device number */
 301         int     minor_num;      /* number of *possible* devices */
 302         int     num;            /* number of devices allocated */
 303         short   type;           /* type of tty driver */
 304         short   subtype;        /* subtype of tty driver */
 305         struct ktermios init_termios; /* Initial termios */
 306         int     flags;          /* tty driver flags */
 307         struct proc_dir_entry *proc_entry; /* /proc fs entry */
 308         struct tty_driver *other; /* only used for the PTY driver */
 309
 310         /*
 311          * Pointer to the tty data structures
 312          */
 313         struct tty_struct **ttys;
 314         struct ktermios **termios;
 315         void *driver_state;
 316
 317         /*
 318          * Driver methods
 319          */
 320
 321         const struct tty_operations *ops;
 322         struct list_head tty_drivers;
 323 };
 324
 325 extern struct list_head tty_drivers;
 326
 327 extern struct tty_driver *alloc_tty_driver(int lines);
 328 extern void put_tty_driver(struct tty_driver *driver);
 329 extern void tty_set_operations(struct tty_driver *driver,
 330                         const struct tty_operations *op);
 331 extern struct tty_driver *tty_find_polling_driver(char *name, int *line);
 332
 333 extern void tty_driver_kref_put(struct tty_driver *driver);
 334
 335 static inline struct tty_driver *tty_driver_kref_get(struct tty_driver *d)
 336 {
 337         kref_get(&d->kref);
 338         return d;
 339 }
 340
 341 /* tty driver magic number */
 342 #define TTY_DRIVER_MAGIC                0x5402
 343
 344 /*
 345  * tty driver flags
 346  *
 347  * TTY_DRIVER_RESET_TERMIOS --- requests the tty layer to reset the
 348  *      termios setting when the last process has closed the device.
 349  *      Used for PTY's, in particular.
 350  *
 351  * TTY_DRIVER_REAL_RAW --- if set, indicates that the driver will
 352  *      guarantee never not to set any special character handling
 353  *      flags if ((IGNBRK || (!BRKINT && !PARMRK)) && (IGNPAR ||
 354  *      !INPCK)).  That is, if there is no reason for the driver to
 355  *      send notifications of parity and break characters up to the
 356  *      line driver, it won't do so.  This allows the line driver to
 357  *      optimize for this case if this flag is set.  (Note that there
 358  *      is also a promise, if the above case is true, not to signal
 359  *      overruns, either.)
 360  *
 361  * TTY_DRIVER_DYNAMIC_DEV --- if set, the individual tty devices need
 362  *      to be registered with a call to tty_register_device() when the
 363  *      device is found in the system and unregistered with a call to
 364  *      tty_unregister_device() so the devices will be show up
 365  *      properly in sysfs.  If not set, driver->num entries will be
 366  *      created by the tty core in sysfs when tty_register_driver() is
 367  *      called.  This is to be used by drivers that have tty devices
 368  *      that can appear and disappear while the main tty driver is
 369  *      registered with the tty core.
 370  *
 371  * TTY_DRIVER_DEVPTS_MEM -- don't use the standard arrays, instead
 372  *      use dynamic memory keyed through the devpts filesystem.  This
 373  *      is only applicable to the pty driver.
 374  *
 375  * TTY_DRIVER_HARDWARE_BREAK -- hardware handles break signals. Pass
 376  *      the requested timeout to the caller instead of using a simple
 377  *      on/off interface.
 378  *
 379  */
 380 #define TTY_DRIVER_INSTALLED            0x0001
 381 #define TTY_DRIVER_RESET_TERMIOS        0x0002
 382 #define TTY_DRIVER_REAL_RAW             0x0004
 383 #define TTY_DRIVER_DYNAMIC_DEV          0x0008
 384 #define TTY_DRIVER_DEVPTS_MEM           0x0010
 385 #define TTY_DRIVER_HARDWARE_BREAK       0x0020
 386
 387 /* tty driver types */
 388 #define TTY_DRIVER_TYPE_SYSTEM          0x0001
 389 #define TTY_DRIVER_TYPE_CONSOLE         0x0002
 390 #define TTY_DRIVER_TYPE_SERIAL          0x0003
 391 #define TTY_DRIVER_TYPE_PTY             0x0004
 392 #define TTY_DRIVER_TYPE_SCC             0x0005  /* scc driver */
 393 #define TTY_DRIVER_TYPE_SYSCONS         0x0006
 394
 395 /* system subtypes (magic, used by tty_io.c) */
 396 #define SYSTEM_TYPE_TTY                 0x0001
 397 #define SYSTEM_TYPE_CONSOLE             0x0002
 398 #define SYSTEM_TYPE_SYSCONS             0x0003
 399 #define SYSTEM_TYPE_SYSPTMX             0x0004
 400
 401 /* pty subtypes (magic, used by tty_io.c) */
 402 #define PTY_TYPE_MASTER                 0x0001
 403 #define PTY_TYPE_SLAVE                  0x0002
 404
 405 /* serial subtype definitions */
 406 #define SERIAL_TYPE_NORMAL      1
 407
 408 #endif /* #ifdef _LINUX_TTY_DRIVER_H */