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  *      Note that this hook may be called from *all* the contexts where one
  54  *      uses tty refcounting (e.g. tty_port_tty_get).
  55  *
  56  *
  57  * void (*cleanup)(struct tty_struct * tty);
  58  *
  59  *      This routine is called asynchronously when a particular tty device
  60  *      is closed for the last time freeing up the resources. This is
  61  *      actually the second part of shutdown for routines that might sleep.
  62  *
  63  *
  64  * int (*write)(struct tty_struct * tty,
  65  *               const unsigned char *buf, int count);
  66  *
  67  *      This routine is called by the kernel to write a series of
  68  *      characters to the tty device.  The characters may come from
  69  *      user space or kernel space.  This routine will return the
  70  *      number of characters actually accepted for writing.
  71  *
  72  *      Optional: Required for writable devices.
  73  *
  74  * int (*put_char)(struct tty_struct *tty, unsigned char ch);
  75  *
  76  *      This routine is called by the kernel to write a single
  77  *      character to the tty device.  If the kernel uses this routine,
  78  *      it must call the flush_chars() routine (if defined) when it is
  79  *      done stuffing characters into the driver.  If there is no room
  80  *      in the queue, the character is ignored.
  81  *
  82  *      Optional: Kernel will use the write method if not provided.
  83  *
  84  *      Note: Do not call this function directly, call tty_put_char
  85  *
  86  * void (*flush_chars)(struct tty_struct *tty);
  87  *
  88  *      This routine is called by the kernel after it has written a
  89  *      series of characters to the tty device using put_char().
  90  *
  91  *      Optional:
  92  *
  93  *      Note: Do not call this function directly, call tty_driver_flush_chars
  94  *
  95  * int  (*write_room)(struct tty_struct *tty);
  96  *
  97  *      This routine returns the numbers of characters the tty driver
  98  *      will accept for queuing to be written.  This number is subject
  99  *      to change as output buffers get emptied, or if the output flow
 100  *      control is acted.
 101  *
 102  *      Required if write method is provided else not needed.
 103  *
 104  *      Note: Do not call this function directly, call tty_write_room
 105  *
 106  * int  (*ioctl)(struct tty_struct *tty, unsigned int cmd, unsigned long arg);
 107  *
 108  *      This routine allows the tty driver to implement
 109  *      device-specific ioctls.  If the ioctl number passed in cmd
 110  *      is not recognized by the driver, it should return ENOIOCTLCMD.
 111  *
 112  *      Optional
 113  *
 114  * long (*compat_ioctl)(struct tty_struct *tty,,
 115  *                      unsigned int cmd, unsigned long arg);
 116  *
 117  *      implement ioctl processing for 32 bit process on 64 bit system
 118  *
 119  *      Optional
 120  *
 121  * void (*set_termios)(struct tty_struct *tty, struct ktermios * old);
 122  *
 123  *      This routine allows the tty driver to be notified when
 124  *      device's termios settings have changed.
 125  *
 126  *      Optional: Called under the termios lock
 127  *
 128  *
 129  * void (*set_ldisc)(struct tty_struct *tty);
 130  *
 131  *      This routine allows the tty driver to be notified when the
 132  *      device's termios settings have changed.
 133  *
 134  *      Optional: Called under BKL (currently)
 135  *
 136  * void (*throttle)(struct tty_struct * tty);
 137  *
 138  *      This routine notifies the tty driver that input buffers for
 139  *      the line discipline are close to full, and it should somehow
 140  *      signal that no more characters should be sent to the tty.
 141  *
 142  *      Optional: Always invoke via tty_throttle(), called under the
 143  *      termios lock.
 144  *
 145  * void (*unthrottle)(struct tty_struct * tty);
 146  *
 147  *      This routine notifies the tty drivers that it should signals
 148  *      that characters can now be sent to the tty without fear of
 149  *      overrunning the input buffers of the line disciplines.
 150  *
 151  *      Optional: Always invoke via tty_unthrottle(), called under the
 152  *      termios lock.
 153  *
 154  * void (*stop)(struct tty_struct *tty);
 155  *
 156  *      This routine notifies the tty driver that it should stop
 157  *      outputting characters to the tty device.
 158  *
 159  *      Optional:
 160  *
 161  *      Note: Call stop_tty not this method.
 162  *
 163  * void (*start)(struct tty_struct *tty);
 164  *
 165  *      This routine notifies the tty driver that it resume sending
 166  *      characters to the tty device.
 167  *
 168  *      Optional:
 169  *
 170  *      Note: Call start_tty not this method.
 171  *
 172  * void (*hangup)(struct tty_struct *tty);
 173  *
 174  *      This routine notifies the tty driver that it should hang up the
 175  *      tty device.
 176  *
 177  *      Optional:
 178  *
 179  * int (*break_ctl)(struct tty_struct *tty, int state);
 180  *
 181  *      This optional routine requests the tty driver to turn on or
 182  *      off BREAK status on the RS-232 port.  If state is -1,
 183  *      then the BREAK status should be turned on; if state is 0, then
 184  *      BREAK should be turned off.
 185  *
 186  *      If this routine is implemented, the high-level tty driver will
 187  *      handle the following ioctls: TCSBRK, TCSBRKP, TIOCSBRK,
 188  *      TIOCCBRK.
 189  *
 190  *      If the driver sets TTY_DRIVER_HARDWARE_BREAK then the interface
 191  *      will also be called with actual times and the hardware is expected
 192  *      to do the delay work itself. 0 and -1 are still used for on/off.
 193  *
 194  *      Optional: Required for TCSBRK/BRKP/etc handling.
 195  *
 196  * void (*wait_until_sent)(struct tty_struct *tty, int timeout);
 197  *
 198  *      This routine waits until the device has written out all of the
 199  *      characters in its transmitter FIFO.
 200  *
 201  *      Optional: If not provided the device is assumed to have no FIFO
 202  *
 203  *      Note: Usually correct to call tty_wait_until_sent
 204  *
 205  * void (*send_xchar)(struct tty_struct *tty, char ch);
 206  *
 207  *      This routine is used to send a high-priority XON/XOFF
 208  *      character to the device.
 209  *
 210  *      Optional: If not provided then the write method is called under
 211  *      the atomic write lock to keep it serialized with the ldisc.
 212  *
 213  * int (*resize)(struct tty_struct *tty, struct winsize *ws)
 214  *
 215  *      Called when a termios request is issued which changes the
 216  *      requested terminal geometry.
 217  *
 218  *      Optional: the default action is to update the termios structure
 219  *      without error. This is usually the correct behaviour. Drivers should
 220  *      not force errors here if they are not resizable objects (eg a serial
 221  *      line). See tty_do_resize() if you need to wrap the standard method
 222  *      in your own logic - the usual case.
 223  *
 224  * void (*set_termiox)(struct tty_struct *tty, struct termiox *new);
 225  *
 226  *      Called when the device receives a termiox based ioctl. Passes down
 227  *      the requested data from user space. This method will not be invoked
 228  *      unless the tty also has a valid tty->termiox pointer.
 229  *
 230  *      Optional: Called under the termios lock
 231  *
 232  * int (*get_icount)(struct tty_struct *tty, struct serial_icounter *icount);
 233  *
 234  *      Called when the device receives a TIOCGICOUNT ioctl. Passed a kernel
 235  *      structure to complete. This method is optional and will only be called
 236  *      if provided (otherwise EINVAL will be returned).
 237  */
 238
 239 #include <linux/export.h>
 240 #include <linux/fs.h>
 241 #include <linux/list.h>
 242 #include <linux/cdev.h>
 243 #include <linux/termios.h>
 244
 245 struct tty_struct;
 246 struct tty_driver;
 247 struct serial_icounter_struct;
 248
 249 struct tty_operations {
 250         struct tty_struct * (*lookup)(struct tty_driver *driver,
 251                         struct inode *inode, int idx);
 252         int  (*install)(struct tty_driver *driver, struct tty_struct *tty);
 253         void (*remove)(struct tty_driver *driver, struct tty_struct *tty);
 254         int  (*open)(struct tty_struct * tty, struct file * filp);
 255         void (*close)(struct tty_struct * tty, struct file * filp);
 256         void (*shutdown)(struct tty_struct *tty);
 257         void (*cleanup)(struct tty_struct *tty);
 258         int  (*write)(struct tty_struct * tty,
 259                       const unsigned char *buf, int count);
 260         int  (*put_char)(struct tty_struct *tty, unsigned char ch);
 261         void (*flush_chars)(struct tty_struct *tty);
 262         int  (*write_room)(struct tty_struct *tty);
 263         int  (*chars_in_buffer)(struct tty_struct *tty);
 264         int  (*ioctl)(struct tty_struct *tty,
 265                     unsigned int cmd, unsigned long arg);
 266         long (*compat_ioctl)(struct tty_struct *tty,
 267                              unsigned int cmd, unsigned long arg);
 268         void (*set_termios)(struct tty_struct *tty, struct ktermios * old);
 269         void (*throttle)(struct tty_struct * tty);
 270         void (*unthrottle)(struct tty_struct * tty);
 271         void (*stop)(struct tty_struct *tty);
 272         void (*start)(struct tty_struct *tty);
 273         void (*hangup)(struct tty_struct *tty);
 274         int (*break_ctl)(struct tty_struct *tty, int state);
 275         void (*flush_buffer)(struct tty_struct *tty);
 276         void (*set_ldisc)(struct tty_struct *tty);
 277         void (*wait_until_sent)(struct tty_struct *tty, int timeout);
 278         void (*send_xchar)(struct tty_struct *tty, char ch);
 279         int (*tiocmget)(struct tty_struct *tty);
 280         int (*tiocmset)(struct tty_struct *tty,
 281                         unsigned int set, unsigned int clear);
 282         int (*resize)(struct tty_struct *tty, struct winsize *ws);
 283         int (*set_termiox)(struct tty_struct *tty, struct termiox *tnew);
 284         int (*get_icount)(struct tty_struct *tty,
 285                                 struct serial_icounter_struct *icount);
 286 #ifdef CONFIG_CONSOLE_POLL
 287         int (*poll_init)(struct tty_driver *driver, int line, char *options);
 288         int (*poll_get_char)(struct tty_driver *driver, int line);
 289         void (*poll_put_char)(struct tty_driver *driver, int line, char ch);
 290 #endif
 291         const struct file_operations *proc_fops;
 292 };
 293
 294 struct tty_driver {
 295         int     magic;          /* magic number for this structure */
 296         struct kref kref;       /* Reference management */
 297         struct cdev cdev;
 298         struct module   *owner;
 299         const char      *driver_name;
 300         const char      *name;
 301         int     name_base;      /* offset of printed name */
 302         int     major;          /* major device number */
 303         int     minor_start;    /* start of minor device number */
 304         int     num;            /* number of devices allocated */
 305         short   type;           /* type of tty driver */
 306         short   subtype;        /* subtype of tty driver */
 307         struct ktermios init_termios; /* Initial termios */
 308         int     flags;          /* tty driver flags */
 309         struct proc_dir_entry *proc_entry; /* /proc fs entry */
 310         struct tty_driver *other; /* only used for the PTY driver */
 311
 312         /*
 313          * Pointer to the tty data structures
 314          */
 315         struct tty_struct **ttys;
 316         struct ktermios **termios;
 317         void *driver_state;
 318
 319         /*
 320          * Driver methods
 321          */
 322
 323         const struct tty_operations *ops;
 324         struct list_head tty_drivers;
 325 };
 326
 327 extern struct list_head tty_drivers;
 328
 329 extern struct tty_driver *__alloc_tty_driver(int lines, struct module *owner);
 330 extern void put_tty_driver(struct tty_driver *driver);
 331 extern void tty_set_operations(struct tty_driver *driver,
 332                         const struct tty_operations *op);
 333 extern struct tty_driver *tty_find_polling_driver(char *name, int *line);
 334
 335 extern void tty_driver_kref_put(struct tty_driver *driver);
 336
 337 #define alloc_tty_driver(lines) __alloc_tty_driver(lines, THIS_MODULE)
 338
 339 static inline struct tty_driver *tty_driver_kref_get(struct tty_driver *d)
 340 {
 341         kref_get(&d->kref);
 342         return d;
 343 }
 344
 345 /* tty driver magic number */
 346 #define TTY_DRIVER_MAGIC                0x5402
 347
 348 /*
 349  * tty driver flags
 350  *
 351  * TTY_DRIVER_RESET_TERMIOS --- requests the tty layer to reset the
 352  *      termios setting when the last process has closed the device.
 353  *      Used for PTY's, in particular.
 354  *
 355  * TTY_DRIVER_REAL_RAW --- if set, indicates that the driver will
 356  *      guarantee never not to set any special character handling
 357  *      flags if ((IGNBRK || (!BRKINT && !PARMRK)) && (IGNPAR ||
 358  *      !INPCK)).  That is, if there is no reason for the driver to
 359  *      send notifications of parity and break characters up to the
 360  *      line driver, it won't do so.  This allows the line driver to
 361  *      optimize for this case if this flag is set.  (Note that there
 362  *      is also a promise, if the above case is true, not to signal
 363  *      overruns, either.)
 364  *
 365  * TTY_DRIVER_DYNAMIC_DEV --- if set, the individual tty devices need
 366  *      to be registered with a call to tty_register_device() when the
 367  *      device is found in the system and unregistered with a call to
 368  *      tty_unregister_device() so the devices will be show up
 369  *      properly in sysfs.  If not set, driver->num entries will be
 370  *      created by the tty core in sysfs when tty_register_driver() is
 371  *      called.  This is to be used by drivers that have tty devices
 372  *      that can appear and disappear while the main tty driver is
 373  *      registered with the tty core.
 374  *
 375  * TTY_DRIVER_DEVPTS_MEM -- don't use the standard arrays, instead
 376  *      use dynamic memory keyed through the devpts filesystem.  This
 377  *      is only applicable to the pty driver.
 378  *
 379  * TTY_DRIVER_HARDWARE_BREAK -- hardware handles break signals. Pass
 380  *      the requested timeout to the caller instead of using a simple
 381  *      on/off interface.
 382  *
 383  */
 384 #define TTY_DRIVER_INSTALLED            0x0001
 385 #define TTY_DRIVER_RESET_TERMIOS        0x0002
 386 #define TTY_DRIVER_REAL_RAW             0x0004
 387 #define TTY_DRIVER_DYNAMIC_DEV          0x0008
 388 #define TTY_DRIVER_DEVPTS_MEM           0x0010
 389 #define TTY_DRIVER_HARDWARE_BREAK       0x0020
 390
 391 /* tty driver types */
 392 #define TTY_DRIVER_TYPE_SYSTEM          0x0001
 393 #define TTY_DRIVER_TYPE_CONSOLE         0x0002
 394 #define TTY_DRIVER_TYPE_SERIAL          0x0003
 395 #define TTY_DRIVER_TYPE_PTY             0x0004
 396 #define TTY_DRIVER_TYPE_SCC             0x0005  /* scc driver */
 397 #define TTY_DRIVER_TYPE_SYSCONS         0x0006
 398
 399 /* system subtypes (magic, used by tty_io.c) */
 400 #define SYSTEM_TYPE_TTY                 0x0001
 401 #define SYSTEM_TYPE_CONSOLE             0x0002
 402 #define SYSTEM_TYPE_SYSCONS             0x0003
 403 #define SYSTEM_TYPE_SYSPTMX             0x0004
 404
 405 /* pty subtypes (magic, used by tty_io.c) */
 406 #define PTY_TYPE_MASTER                 0x0001
 407 #define PTY_TYPE_SLAVE                  0x0002
 408
 409 /* serial subtype definitions */
 410 #define SERIAL_TYPE_NORMAL      1
 411
 412 #endif /* #ifdef _LINUX_TTY_DRIVER_H */