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  *      Note: called even if the corresponding open() failed.
  44  *
  45  *      Required method.
  46  *
  47  * void (*shutdown)(struct tty_struct * tty);
  48  *
  49  *      This routine is called under the tty lock when a particular tty device
  50  *      is closed for the last time. It executes before the tty resources
  51  *      are freed so may execute while another function holds a tty kref.
  52  *
  53  * void (*cleanup)(struct tty_struct * tty);
  54  *
  55  *      This routine is called asynchronously when a particular tty device
  56  *      is closed for the last time freeing up the resources. This is
  57  *      actually the second part of shutdown for routines that might sleep.
  58  *
  59  *
  60  * int (*write)(struct tty_struct * tty,
  61  *               const unsigned char *buf, int count);
  62  *
  63  *      This routine is called by the kernel to write a series of
  64  *      characters to the tty device.  The characters may come from
  65  *      user space or kernel space.  This routine will return the
  66  *      number of characters actually accepted for writing.
  67  *
  68  *      Optional: Required for writable devices.
  69  *
  70  * int (*put_char)(struct tty_struct *tty, unsigned char ch);
  71  *
  72  *      This routine is called by the kernel to write a single
  73  *      character to the tty device.  If the kernel uses this routine,
  74  *      it must call the flush_chars() routine (if defined) when it is
  75  *      done stuffing characters into the driver.  If there is no room
  76  *      in the queue, the character is ignored.
  77  *
  78  *      Optional: Kernel will use the write method if not provided.
  79  *
  80  *      Note: Do not call this function directly, call tty_put_char
  81  *
  82  * void (*flush_chars)(struct tty_struct *tty);
  83  *
  84  *      This routine is called by the kernel after it has written a
  85  *      series of characters to the tty device using put_char().
  86  *
  87  *      Optional:
  88  *
  89  *      Note: Do not call this function directly, call tty_driver_flush_chars
  90  *
  91  * int  (*write_room)(struct tty_struct *tty);
  92  *
  93  *      This routine returns the numbers of characters the tty driver
  94  *      will accept for queuing to be written.  This number is subject
  95  *      to change as output buffers get emptied, or if the output flow
  96  *      control is acted.
  97  *
  98  *      Required if write method is provided else not needed.
  99  *
 100  *      Note: Do not call this function directly, call tty_write_room
 101  *
 102  * int  (*ioctl)(struct tty_struct *tty, unsigned int cmd, unsigned long arg);
 103  *
 104  *      This routine allows the tty driver to implement
 105  *      device-specific ioctls.  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,,
 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 hang up the
 171  *      tty device.
 172  *
 173  *      Optional:
 174  *
 175  * int (*break_ctl)(struct tty_struct *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  * int (*get_icount)(struct tty_struct *tty, struct serial_icounter *icount);
 229  *
 230  *      Called when the device receives a TIOCGICOUNT ioctl. Passed a kernel
 231  *      structure to complete. This method is optional and will only be called
 232  *      if provided (otherwise EINVAL will be returned).
 233  */
 234
 235 #include <linux/export.h>
 236 #include <linux/fs.h>
 237 #include <linux/list.h>
 238 #include <linux/cdev.h>
 239 #include <linux/termios.h>
 240
 241 struct tty_struct;
 242 struct tty_driver;
 243 struct serial_icounter_struct;
 244
 245 struct tty_operations {
 246         struct tty_struct * (*lookup)(struct tty_driver *driver,
 247                         struct inode *inode, int idx);
 248         int  (*install)(struct tty_driver *driver, struct tty_struct *tty);
 249         void (*remove)(struct tty_driver *driver, struct tty_struct *tty);
 250         int  (*open)(struct tty_struct * tty, struct file * filp);
 251         void (*close)(struct tty_struct * tty, struct file * filp);
 252         void (*shutdown)(struct tty_struct *tty);
 253         void (*cleanup)(struct tty_struct *tty);
 254         int  (*write)(struct tty_struct * tty,
 255                       const unsigned char *buf, int count);
 256         int  (*put_char)(struct tty_struct *tty, unsigned char ch);
 257         void (*flush_chars)(struct tty_struct *tty);
 258         int  (*write_room)(struct tty_struct *tty);
 259         int  (*chars_in_buffer)(struct tty_struct *tty);
 260         int  (*ioctl)(struct tty_struct *tty,
 261                     unsigned int cmd, unsigned long arg);
 262         long (*compat_ioctl)(struct tty_struct *tty,
 263                              unsigned int cmd, unsigned long arg);
 264         void (*set_termios)(struct tty_struct *tty, struct ktermios * old);
 265         void (*throttle)(struct tty_struct * tty);
 266         void (*unthrottle)(struct tty_struct * tty);
 267         void (*stop)(struct tty_struct *tty);
 268         void (*start)(struct tty_struct *tty);
 269         void (*hangup)(struct tty_struct *tty);
 270         int (*break_ctl)(struct tty_struct *tty, int state);
 271         void (*flush_buffer)(struct tty_struct *tty);
 272         void (*set_ldisc)(struct tty_struct *tty);
 273         void (*wait_until_sent)(struct tty_struct *tty, int timeout);
 274         void (*send_xchar)(struct tty_struct *tty, char ch);
 275         int (*tiocmget)(struct tty_struct *tty);
 276         int (*tiocmset)(struct tty_struct *tty,
 277                         unsigned int set, unsigned int clear);
 278         int (*resize)(struct tty_struct *tty, struct winsize *ws);
 279         int (*set_termiox)(struct tty_struct *tty, struct termiox *tnew);
 280         int (*get_icount)(struct tty_struct *tty,
 281                                 struct serial_icounter_struct *icount);
 282 #ifdef CONFIG_CONSOLE_POLL
 283         int (*poll_init)(struct tty_driver *driver, int line, char *options);
 284         int (*poll_get_char)(struct tty_driver *driver, int line);
 285         void (*poll_put_char)(struct tty_driver *driver, int line, char ch);
 286 #endif
 287         const struct file_operations *proc_fops;
 288 };
 289
 290 struct tty_driver {
 291         int     magic;          /* magic number for this structure */
 292         struct kref kref;       /* Reference management */
 293         struct cdev *cdevs;
 294         struct module   *owner;
 295         const char      *driver_name;
 296         const char      *name;
 297         int     name_base;      /* offset of printed name */
 298         int     major;          /* major device number */
 299         int     minor_start;    /* start of minor device number */
 300         unsigned int    num;    /* number of devices allocated */
 301         short   type;           /* type of tty driver */
 302         short   subtype;        /* subtype of tty driver */
 303         struct ktermios init_termios; /* Initial termios */
 304         unsigned long   flags;          /* tty driver flags */
 305         struct proc_dir_entry *proc_entry; /* /proc fs entry */
 306         struct tty_driver *other; /* only used for the PTY driver */
 307
 308         /*
 309          * Pointer to the tty data structures
 310          */
 311         struct tty_struct **ttys;
 312         struct tty_port **ports;
 313         struct ktermios **termios;
 314         void *driver_state;
 315
 316         /*
 317          * Driver methods
 318          */
 319
 320         const struct tty_operations *ops;
 321         struct list_head tty_drivers;
 322 };
 323
 324 extern struct list_head tty_drivers;
 325
 326 extern struct tty_driver *__tty_alloc_driver(unsigned int lines,
 327                 struct module *owner, unsigned long flags);
 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 /* Use TTY_DRIVER_* flags below */
 336 #define tty_alloc_driver(lines, flags) \
 337                 __tty_alloc_driver(lines, THIS_MODULE, flags)
 338
 339 /*
 340  * DEPRECATED Do not use this in new code, use tty_alloc_driver instead.
 341  * (And change the return value checks.)
 342  */
 343 static inline struct tty_driver *alloc_tty_driver(unsigned int lines)
 344 {
 345         struct tty_driver *ret = tty_alloc_driver(lines, 0);
 346         if (IS_ERR(ret))
 347                 return NULL;
 348         return ret;
 349 }
 350
 351 static inline struct tty_driver *tty_driver_kref_get(struct tty_driver *d)
 352 {
 353         kref_get(&d->kref);
 354         return d;
 355 }
 356
 357 /* tty driver magic number */
 358 #define TTY_DRIVER_MAGIC                0x5402
 359
 360 /*
 361  * tty driver flags
 362  *
 363  * TTY_DRIVER_RESET_TERMIOS --- requests the tty layer to reset the
 364  *      termios setting when the last process has closed the device.
 365  *      Used for PTY's, in particular.
 366  *
 367  * TTY_DRIVER_REAL_RAW --- if set, indicates that the driver will
 368  *      guarantee never not to set any special character handling
 369  *      flags if ((IGNBRK || (!BRKINT && !PARMRK)) && (IGNPAR ||
 370  *      !INPCK)).  That is, if there is no reason for the driver to
 371  *      send notifications of parity and break characters up to the
 372  *      line driver, it won't do so.  This allows the line driver to
 373  *      optimize for this case if this flag is set.  (Note that there
 374  *      is also a promise, if the above case is true, not to signal
 375  *      overruns, either.)
 376  *
 377  * TTY_DRIVER_DYNAMIC_DEV --- if set, the individual tty devices need
 378  *      to be registered with a call to tty_register_device() when the
 379  *      device is found in the system and unregistered with a call to
 380  *      tty_unregister_device() so the devices will be show up
 381  *      properly in sysfs.  If not set, driver->num entries will be
 382  *      created by the tty core in sysfs when tty_register_driver() is
 383  *      called.  This is to be used by drivers that have tty devices
 384  *      that can appear and disappear while the main tty driver is
 385  *      registered with the tty core.
 386  *
 387  * TTY_DRIVER_DEVPTS_MEM -- don't use the standard arrays, instead
 388  *      use dynamic memory keyed through the devpts filesystem.  This
 389  *      is only applicable to the pty driver.
 390  *
 391  * TTY_DRIVER_HARDWARE_BREAK -- hardware handles break signals. Pass
 392  *      the requested timeout to the caller instead of using a simple
 393  *      on/off interface.
 394  *
 395  * TTY_DRIVER_DYNAMIC_ALLOC -- do not allocate structures which are
 396  *      needed per line for this driver as it would waste memory.
 397  *      The driver will take care.
 398  *
 399  * TTY_DRIVER_UNNUMBERED_NODE -- do not create numbered /dev nodes. In
 400  *      other words create /dev/ttyprintk and not /dev/ttyprintk0.
 401  *      Applicable only when a driver for a single tty device is
 402  *      being allocated.
 403  */
 404 #define TTY_DRIVER_INSTALLED            0x0001
 405 #define TTY_DRIVER_RESET_TERMIOS        0x0002
 406 #define TTY_DRIVER_REAL_RAW             0x0004
 407 #define TTY_DRIVER_DYNAMIC_DEV          0x0008
 408 #define TTY_DRIVER_DEVPTS_MEM           0x0010
 409 #define TTY_DRIVER_HARDWARE_BREAK       0x0020
 410 #define TTY_DRIVER_DYNAMIC_ALLOC        0x0040
 411 #define TTY_DRIVER_UNNUMBERED_NODE      0x0080
 412
 413 /* tty driver types */
 414 #define TTY_DRIVER_TYPE_SYSTEM          0x0001
 415 #define TTY_DRIVER_TYPE_CONSOLE         0x0002
 416 #define TTY_DRIVER_TYPE_SERIAL          0x0003
 417 #define TTY_DRIVER_TYPE_PTY             0x0004
 418 #define TTY_DRIVER_TYPE_SCC             0x0005  /* scc driver */
 419 #define TTY_DRIVER_TYPE_SYSCONS         0x0006
 420
 421 /* system subtypes (magic, used by tty_io.c) */
 422 #define SYSTEM_TYPE_TTY                 0x0001
 423 #define SYSTEM_TYPE_CONSOLE             0x0002
 424 #define SYSTEM_TYPE_SYSCONS             0x0003
 425 #define SYSTEM_TYPE_SYSPTMX             0x0004
 426
 427 /* pty subtypes (magic, used by tty_io.c) */
 428 #define PTY_TYPE_MASTER                 0x0001
 429 #define PTY_TYPE_SLAVE                  0x0002
 430
 431 /* serial subtype definitions */
 432 #define SERIAL_TYPE_NORMAL      1
 433
 434 #endif /* #ifdef _LINUX_TTY_DRIVER_H */