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