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 under the tty lock when a particular tty device
  49  *      is closed for the last time. It executes before the tty resources
  50  *      are freed so may execute while another function holds a tty kref.
  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, unsigned int cmd, unsigned long arg);
 102  *
 103  *      This routine allows the tty driver to implement
 104  *      device-specific ioctls.  If the ioctl number passed in cmd
 105  *      is not recognized by the driver, it should return ENOIOCTLCMD.
 106  *
 107  *      Optional
 108  *
 109  * long (*compat_ioctl)(struct tty_struct *tty,,
 110  *                      unsigned int cmd, unsigned long arg);
 111  *
 112  *      implement ioctl processing for 32 bit process on 64 bit system
 113  *
 114  *      Optional
 115  *
 116  * void (*set_termios)(struct tty_struct *tty, struct ktermios * old);
 117  *
 118  *      This routine allows the tty driver to be notified when
 119  *      device's termios settings have changed.
 120  *
 121  *      Optional: Called under the termios lock
 122  *
 123  *
 124  * void (*set_ldisc)(struct tty_struct *tty);
 125  *
 126  *      This routine allows the tty driver to be notified when the
 127  *      device's termios settings have changed.
 128  *
 129  *      Optional: Called under BKL (currently)
 130  *
 131  * void (*throttle)(struct tty_struct * tty);
 132  *
 133  *      This routine notifies the tty driver that input buffers for
 134  *      the line discipline are close to full, and it should somehow
 135  *      signal that no more characters should be sent to the tty.
 136  *
 137  *      Optional: Always invoke via tty_throttle(), called under the
 138  *      termios lock.
 139  *
 140  * void (*unthrottle)(struct tty_struct * tty);
 141  *
 142  *      This routine notifies the tty drivers that it should signals
 143  *      that characters can now be sent to the tty without fear of
 144  *      overrunning the input buffers of the line disciplines.
 145  *
 146  *      Optional: Always invoke via tty_unthrottle(), called under the
 147  *      termios lock.
 148  *
 149  * void (*stop)(struct tty_struct *tty);
 150  *
 151  *      This routine notifies the tty driver that it should stop
 152  *      outputting characters to the tty device.
 153  *
 154  *      Optional:
 155  *
 156  *      Note: Call stop_tty not this method.
 157  *
 158  * void (*start)(struct tty_struct *tty);
 159  *
 160  *      This routine notifies the tty driver that it resume sending
 161  *      characters to the tty device.
 162  *
 163  *      Optional:
 164  *
 165  *      Note: Call start_tty not this method.
 166  *
 167  * void (*hangup)(struct tty_struct *tty);
 168  *
 169  *      This routine notifies the tty driver that it should hang up the
 170  *      tty device.
 171  *
 172  *      Optional:
 173  *
 174  * int (*break_ctl)(struct tty_struct *tty, int state);
 175  *
 176  *      This optional routine requests the tty driver to turn on or
 177  *      off BREAK status on the RS-232 port.  If state is -1,
 178  *      then the BREAK status should be turned on; if state is 0, then
 179  *      BREAK should be turned off.
 180  *
 181  *      If this routine is implemented, the high-level tty driver will
 182  *      handle the following ioctls: TCSBRK, TCSBRKP, TIOCSBRK,
 183  *      TIOCCBRK.
 184  *
 185  *      If the driver sets TTY_DRIVER_HARDWARE_BREAK then the interface
 186  *      will also be called with actual times and the hardware is expected
 187  *      to do the delay work itself. 0 and -1 are still used for on/off.
 188  *
 189  *      Optional: Required for TCSBRK/BRKP/etc handling.
 190  *
 191  * void (*wait_until_sent)(struct tty_struct *tty, int timeout);
 192  *
 193  *      This routine waits until the device has written out all of the
 194  *      characters in its transmitter FIFO.
 195  *
 196  *      Optional: If not provided the device is assumed to have no FIFO
 197  *
 198  *      Note: Usually correct to call tty_wait_until_sent
 199  *
 200  * void (*send_xchar)(struct tty_struct *tty, char ch);
 201  *
 202  *      This routine is used to send a high-priority XON/XOFF
 203  *      character to the device.
 204  *
 205  *      Optional: If not provided then the write method is called under
 206  *      the atomic write lock to keep it serialized with the ldisc.
 207  *
 208  * int (*resize)(struct tty_struct *tty, struct winsize *ws)
 209  *
 210  *      Called when a termios request is issued which changes the
 211  *      requested terminal geometry.
 212  *
 213  *      Optional: the default action is to update the termios structure
 214  *      without error. This is usually the correct behaviour. Drivers should
 215  *      not force errors here if they are not resizable objects (eg a serial
 216  *      line). See tty_do_resize() if you need to wrap the standard method
 217  *      in your own logic - the usual case.
 218  *
 219  * void (*set_termiox)(struct tty_struct *tty, struct termiox *new);
 220  *
 221  *      Called when the device receives a termiox based ioctl. Passes down
 222  *      the requested data from user space. This method will not be invoked
 223  *      unless the tty also has a valid tty->termiox pointer.
 224  *
 225  *      Optional: Called under the termios lock
 226  *
 227  * int (*get_icount)(struct tty_struct *tty, struct serial_icounter *icount);
 228  *
 229  *      Called when the device receives a TIOCGICOUNT ioctl. Passed a kernel
 230  *      structure to complete. This method is optional and will only be called
 231  *      if provided (otherwise EINVAL will be returned).
 232  */
 233
 234 #include <linux/export.h>
 235 #include <linux/fs.h>
 236 #include <linux/list.h>
 237 #include <linux/cdev.h>
 238 #include <linux/termios.h>
 239
 240 struct tty_struct;
 241 struct tty_driver;
 242 struct serial_icounter_struct;
 243
 244 struct tty_operations {
 245         struct tty_struct * (*lookup)(struct tty_driver *driver,
 246                         struct inode *inode, int idx);
 247         int  (*install)(struct tty_driver *driver, struct tty_struct *tty);
 248         void (*remove)(struct tty_driver *driver, struct tty_struct *tty);
 249         int  (*open)(struct tty_struct * tty, struct file * filp);
 250         void (*close)(struct tty_struct * tty, struct file * filp);
 251         void (*shutdown)(struct tty_struct *tty);
 252         void (*cleanup)(struct tty_struct *tty);
 253         int  (*write)(struct tty_struct * tty,
 254                       const unsigned char *buf, int count);
 255         int  (*put_char)(struct tty_struct *tty, unsigned char ch);
 256         void (*flush_chars)(struct tty_struct *tty);
 257         int  (*write_room)(struct tty_struct *tty);
 258         int  (*chars_in_buffer)(struct tty_struct *tty);
 259         int  (*ioctl)(struct tty_struct *tty,
 260                     unsigned int cmd, unsigned long arg);
 261         long (*compat_ioctl)(struct tty_struct *tty,
 262                              unsigned int cmd, unsigned long arg);
 263         void (*set_termios)(struct tty_struct *tty, struct ktermios * old);
 264         void (*throttle)(struct tty_struct * tty);
 265         void (*unthrottle)(struct tty_struct * tty);
 266         void (*stop)(struct tty_struct *tty);
 267         void (*start)(struct tty_struct *tty);
 268         void (*hangup)(struct tty_struct *tty);
 269         int (*break_ctl)(struct tty_struct *tty, int state);
 270         void (*flush_buffer)(struct tty_struct *tty);
 271         void (*set_ldisc)(struct tty_struct *tty);
 272         void (*wait_until_sent)(struct tty_struct *tty, int timeout);
 273         void (*send_xchar)(struct tty_struct *tty, char ch);
 274         int (*tiocmget)(struct tty_struct *tty);
 275         int (*tiocmset)(struct tty_struct *tty,
 276                         unsigned int set, unsigned int clear);
 277         int (*resize)(struct tty_struct *tty, struct winsize *ws);
 278         int (*set_termiox)(struct tty_struct *tty, struct termiox *tnew);
 279         int (*get_icount)(struct tty_struct *tty,
 280                                 struct serial_icounter_struct *icount);
 281 #ifdef CONFIG_CONSOLE_POLL
 282         int (*poll_init)(struct tty_driver *driver, int line, char *options);
 283         int (*poll_get_char)(struct tty_driver *driver, int line);
 284         void (*poll_put_char)(struct tty_driver *driver, int line, char ch);
 285 #endif
 286         const struct file_operations *proc_fops;
 287 };
 288
 289 struct tty_driver {
 290         int     magic;          /* magic number for this structure */
 291         struct kref kref;       /* Reference management */
 292         struct cdev *cdevs;
 293         struct module   *owner;
 294         const char      *driver_name;
 295         const char      *name;
 296         int     name_base;      /* offset of printed name */
 297         int     major;          /* major device number */
 298         int     minor_start;    /* start of minor device number */
 299         unsigned int    num;    /* number of devices allocated */
 300         short   type;           /* type of tty driver */
 301         short   subtype;        /* subtype of tty driver */
 302         struct ktermios init_termios; /* Initial termios */
 303         unsigned long   flags;          /* tty driver flags */
 304         struct proc_dir_entry *proc_entry; /* /proc fs entry */
 305         struct tty_driver *other; /* only used for the PTY driver */
 306
 307         /*
 308          * Pointer to the tty data structures
 309          */
 310         struct tty_struct **ttys;
 311         struct tty_port **ports;
 312         struct ktermios **termios;
 313         void *driver_state;
 314
 315         /*
 316          * Driver methods
 317          */
 318
 319         const struct tty_operations *ops;
 320         struct list_head tty_drivers;
 321 };
 322
 323 extern struct list_head tty_drivers;
 324
 325 extern struct tty_driver *__tty_alloc_driver(unsigned int lines,
 326                 struct module *owner, unsigned long flags);
 327 extern void put_tty_driver(struct tty_driver *driver);
 328 extern void tty_set_operations(struct tty_driver *driver,
 329                         const struct tty_operations *op);
 330 extern struct tty_driver *tty_find_polling_driver(char *name, int *line);
 331
 332 extern void tty_driver_kref_put(struct tty_driver *driver);
 333
 334 /* Use TTY_DRIVER_* flags below */
 335 #define tty_alloc_driver(lines, flags) \
 336                 __tty_alloc_driver(lines, THIS_MODULE, flags)
 337
 338 /*
 339  * DEPRECATED Do not use this in new code, use tty_alloc_driver instead.
 340  * (And change the return value checks.)
 341  */
 342 static inline struct tty_driver *alloc_tty_driver(unsigned int lines)
 343 {
 344         struct tty_driver *ret = tty_alloc_driver(lines, 0);
 345         if (IS_ERR(ret))
 346                 return NULL;
 347         return ret;
 348 }
 349
 350 static inline struct tty_driver *tty_driver_kref_get(struct tty_driver *d)
 351 {
 352         kref_get(&d->kref);
 353         return d;
 354 }
 355
 356 /* tty driver magic number */
 357 #define TTY_DRIVER_MAGIC                0x5402
 358
 359 /*
 360  * tty driver flags
 361  *
 362  * TTY_DRIVER_RESET_TERMIOS --- requests the tty layer to reset the
 363  *      termios setting when the last process has closed the device.
 364  *      Used for PTY's, in particular.
 365  *
 366  * TTY_DRIVER_REAL_RAW --- if set, indicates that the driver will
 367  *      guarantee never not to set any special character handling
 368  *      flags if ((IGNBRK || (!BRKINT && !PARMRK)) && (IGNPAR ||
 369  *      !INPCK)).  That is, if there is no reason for the driver to
 370  *      send notifications of parity and break characters up to the
 371  *      line driver, it won't do so.  This allows the line driver to
 372  *      optimize for this case if this flag is set.  (Note that there
 373  *      is also a promise, if the above case is true, not to signal
 374  *      overruns, either.)
 375  *
 376  * TTY_DRIVER_DYNAMIC_DEV --- if set, the individual tty devices need
 377  *      to be registered with a call to tty_register_device() when the
 378  *      device is found in the system and unregistered with a call to
 379  *      tty_unregister_device() so the devices will be show up
 380  *      properly in sysfs.  If not set, driver->num entries will be
 381  *      created by the tty core in sysfs when tty_register_driver() is
 382  *      called.  This is to be used by drivers that have tty devices
 383  *      that can appear and disappear while the main tty driver is
 384  *      registered with the tty core.
 385  *
 386  * TTY_DRIVER_DEVPTS_MEM -- don't use the standard arrays, instead
 387  *      use dynamic memory keyed through the devpts filesystem.  This
 388  *      is only applicable to the pty driver.
 389  *
 390  * TTY_DRIVER_HARDWARE_BREAK -- hardware handles break signals. Pass
 391  *      the requested timeout to the caller instead of using a simple
 392  *      on/off interface.
 393  *
 394  * TTY_DRIVER_DYNAMIC_ALLOC -- do not allocate structures which are
 395  *      needed per line for this driver as it would waste memory.
 396  *      The driver will take care.
 397  *
 398  * TTY_DRIVER_UNNUMBERED_NODE -- do not create numbered /dev nodes. In
 399  *      other words create /dev/ttyprintk and not /dev/ttyprintk0.
 400  *      Applicable only when a driver for a single tty device is
 401  *      being allocated.
 402  */
 403 #define TTY_DRIVER_INSTALLED            0x0001
 404 #define TTY_DRIVER_RESET_TERMIOS        0x0002
 405 #define TTY_DRIVER_REAL_RAW             0x0004
 406 #define TTY_DRIVER_DYNAMIC_DEV          0x0008
 407 #define TTY_DRIVER_DEVPTS_MEM           0x0010
 408 #define TTY_DRIVER_HARDWARE_BREAK       0x0020
 409 #define TTY_DRIVER_DYNAMIC_ALLOC        0x0040
 410 #define TTY_DRIVER_UNNUMBERED_NODE      0x0080
 411
 412 /* tty driver types */
 413 #define TTY_DRIVER_TYPE_SYSTEM          0x0001
 414 #define TTY_DRIVER_TYPE_CONSOLE         0x0002
 415 #define TTY_DRIVER_TYPE_SERIAL          0x0003
 416 #define TTY_DRIVER_TYPE_PTY             0x0004
 417 #define TTY_DRIVER_TYPE_SCC             0x0005  /* scc driver */
 418 #define TTY_DRIVER_TYPE_SYSCONS         0x0006
 419
 420 /* system subtypes (magic, used by tty_io.c) */
 421 #define SYSTEM_TYPE_TTY                 0x0001
 422 #define SYSTEM_TYPE_CONSOLE             0x0002
 423 #define SYSTEM_TYPE_SYSCONS             0x0003
 424 #define SYSTEM_TYPE_SYSPTMX             0x0004
 425
 426 /* pty subtypes (magic, used by tty_io.c) */
 427 #define PTY_TYPE_MASTER                 0x0001
 428 #define PTY_TYPE_SLAVE                  0x0002
 429
 430 /* serial subtype definitions */
 431 #define SERIAL_TYPE_NORMAL      1
 432
 433 #endif /* #ifdef _LINUX_TTY_DRIVER_H */