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  * int  (*open)(struct tty_struct * tty, struct file * filp);
  11  *
  12  *      This routine is called when a particular tty device is opened.
  13  *      This routine is mandatory; if this routine is not filled in,
  14  *      the attempted open will fail with ENODEV.
  15  *
  16  *      Required method.
  17  *
  18  * void (*close)(struct tty_struct * tty, struct file * filp);
  19  *
  20  *      This routine is called when a particular tty device is closed.
  21  *
  22  *      Required method.
  23  *
  24  * int (*write)(struct tty_struct * tty,
  25  *               const unsigned char *buf, int count);
  26  *
  27  *      This routine is called by the kernel to write a series of
  28  *      characters to the tty device.  The characters may come from
  29  *      user space or kernel space.  This routine will return the
  30  *      number of characters actually accepted for writing.
  31  *
  32  *      Optional: Required for writable devices.
  33  *
  34  * int (*put_char)(struct tty_struct *tty, unsigned char ch);
  35  *
  36  *      This routine is called by the kernel to write a single
  37  *      character to the tty device.  If the kernel uses this routine,
  38  *      it must call the flush_chars() routine (if defined) when it is
  39  *      done stuffing characters into the driver.  If there is no room
  40  *      in the queue, the character is ignored.
  41  *
  42  *      Optional: Kernel will use the write method if not provided.
  43  *
  44  *      Note: Do not call this function directly, call tty_put_char
  45  *
  46  * void (*flush_chars)(struct tty_struct *tty);
  47  *
  48  *      This routine is called by the kernel after it has written a
  49  *      series of characters to the tty device using put_char().
  50  *
  51  *      Optional:
  52  *
  53  *      Note: Do not call this function directly, call tty_driver_flush_chars
  54  *
  55  * int  (*write_room)(struct tty_struct *tty);
  56  *
  57  *      This routine returns the numbers of characters the tty driver
  58  *      will accept for queuing to be written.  This number is subject
  59  *      to change as output buffers get emptied, or if the output flow
  60  *      control is acted.
  61  *
  62  *      Required if write method is provided else not needed.
  63  *
  64  *      Note: Do not call this function directly, call tty_write_room
  65  *
  66  * int  (*ioctl)(struct tty_struct *tty, struct file * file,
  67  *          unsigned int cmd, unsigned long arg);
  68  *
  69  *      This routine allows the tty driver to implement
  70  *      device-specific ioctl's.  If the ioctl number passed in cmd
  71  *      is not recognized by the driver, it should return ENOIOCTLCMD.
  72  *
  73  *      Optional
  74  *
  75  * long (*compat_ioctl)(struct tty_struct *tty, struct file * file,
  76  *                      unsigned int cmd, unsigned long arg);
  77  *
  78  *      implement ioctl processing for 32 bit process on 64 bit system
  79  *
  80  *      Optional
  81  *
  82  * void (*set_termios)(struct tty_struct *tty, struct ktermios * old);
  83  *
  84  *      This routine allows the tty driver to be notified when
  85  *      device's termios settings have changed.
  86  *
  87  *      Optional: Called under the termios lock
  88  *
  89  *
  90  * void (*set_ldisc)(struct tty_struct *tty);
  91  *
  92  *      This routine allows the tty driver to be notified when the
  93  *      device's termios settings have changed.
  94  *
  95  *      Optional: Called under BKL (currently)
  96  *
  97  * void (*throttle)(struct tty_struct * tty);
  98  *
  99  *      This routine notifies the tty driver that input buffers for
 100  *      the line discipline are close to full, and it should somehow
 101  *      signal that no more characters should be sent to the tty.
 102  *
 103  *      Optional: Always invoke via tty_throttle();
 104  *
 105  * void (*unthrottle)(struct tty_struct * tty);
 106  *
 107  *      This routine notifies the tty drivers that it should signals
 108  *      that characters can now be sent to the tty without fear of
 109  *      overrunning the input buffers of the line disciplines.
 110  *
 111  *      Optional: Always invoke via tty_unthrottle();
 112  *
 113  * void (*stop)(struct tty_struct *tty);
 114  *
 115  *      This routine notifies the tty driver that it should stop
 116  *      outputting characters to the tty device.
 117  *
 118  *      Optional:
 119  *
 120  *      Note: Call stop_tty not this method.
 121  *
 122  * void (*start)(struct tty_struct *tty);
 123  *
 124  *      This routine notifies the tty driver that it resume sending
 125  *      characters to the tty device.
 126  *
 127  *      Optional:
 128  *
 129  *      Note: Call start_tty not this method.
 130  *
 131  * void (*hangup)(struct tty_struct *tty);
 132  *
 133  *      This routine notifies the tty driver that it should hangup the
 134  *      tty device.
 135  *
 136  *      Optional:
 137  *
 138  * int (*break_ctl)(struct tty_stuct *tty, int state);
 139  *
 140  *      This optional routine requests the tty driver to turn on or
 141  *      off BREAK status on the RS-232 port.  If state is -1,
 142  *      then the BREAK status should be turned on; if state is 0, then
 143  *      BREAK should be turned off.
 144  *
 145  *      If this routine is implemented, the high-level tty driver will
 146  *      handle the following ioctls: TCSBRK, TCSBRKP, TIOCSBRK,
 147  *      TIOCCBRK.
 148  *
 149  *      If the driver sets TTY_DRIVER_HARDWARE_BREAK then the interface
 150  *      will also be called with actual times and the hardware is expected
 151  *      to do the delay work itself. 0 and -1 are still used for on/off.
 152  *
 153  *      Optional: Required for TCSBRK/BRKP/etc handling.
 154  *
 155  * void (*wait_until_sent)(struct tty_struct *tty, int timeout);
 156  *
 157  *      This routine waits until the device has written out all of the
 158  *      characters in its transmitter FIFO.
 159  *
 160  *      Optional: If not provided the device is assumed to have no FIFO
 161  *
 162  *      Note: Usually correct to call tty_wait_until_sent
 163  *
 164  * void (*send_xchar)(struct tty_struct *tty, char ch);
 165  *
 166  *      This routine is used to send a high-priority XON/XOFF
 167  *      character to the device.
 168  *
 169  *      Optional: If not provided then the write method is called under
 170  *      the atomic write lock to keep it serialized with the ldisc.
 171  *
 172  * int (*resize)(struct tty_struct *tty, struct tty_struct *real_tty,
 173  *                              unsigned int rows, unsigned int cols);
 174  *
 175  *      Called when a termios request is issued which changes the
 176  *      requested terminal geometry.
 177  *
 178  *      Optional: the default action is to update the termios structure
 179  *      without error. This is usually the correct behaviour. Drivers should
 180  *      not force errors here if they are not resizable objects (eg a serial
 181  *      line). See tty_do_resize() if you need to wrap the standard method
 182  *      in your own logic - the usual case.
 183  *
 184  * void (*set_termiox)(struct tty_struct *tty, struct termiox *new);
 185  *
 186  *      Called when the device receives a termiox based ioctl. Passes down
 187  *      the requested data from user space. This method will not be invoked
 188  *      unless the tty also has a valid tty->termiox pointer.
 189  *
 190  *      Optional: Called under the termios lock
 191  */
 192
 193 #include <linux/fs.h>
 194 #include <linux/list.h>
 195 #include <linux/cdev.h>
 196
 197 struct tty_struct;
 198 struct tty_driver;
 199
 200 struct tty_operations {
 201         int  (*open)(struct tty_struct * tty, struct file * filp);
 202         void (*close)(struct tty_struct * tty, struct file * filp);
 203         int  (*write)(struct tty_struct * tty,
 204                       const unsigned char *buf, int count);
 205         int  (*put_char)(struct tty_struct *tty, unsigned char ch);
 206         void (*flush_chars)(struct tty_struct *tty);
 207         int  (*write_room)(struct tty_struct *tty);
 208         int  (*chars_in_buffer)(struct tty_struct *tty);
 209         int  (*ioctl)(struct tty_struct *tty, struct file * file,
 210                     unsigned int cmd, unsigned long arg);
 211         long (*compat_ioctl)(struct tty_struct *tty, struct file * file,
 212                              unsigned int cmd, unsigned long arg);
 213         void (*set_termios)(struct tty_struct *tty, struct ktermios * old);
 214         void (*throttle)(struct tty_struct * tty);
 215         void (*unthrottle)(struct tty_struct * tty);
 216         void (*stop)(struct tty_struct *tty);
 217         void (*start)(struct tty_struct *tty);
 218         void (*hangup)(struct tty_struct *tty);
 219         int (*break_ctl)(struct tty_struct *tty, int state);
 220         void (*flush_buffer)(struct tty_struct *tty);
 221         void (*set_ldisc)(struct tty_struct *tty);
 222         void (*wait_until_sent)(struct tty_struct *tty, int timeout);
 223         void (*send_xchar)(struct tty_struct *tty, char ch);
 224         int (*read_proc)(char *page, char **start, off_t off,
 225                           int count, int *eof, void *data);
 226         int (*tiocmget)(struct tty_struct *tty, struct file *file);
 227         int (*tiocmset)(struct tty_struct *tty, struct file *file,
 228                         unsigned int set, unsigned int clear);
 229         int (*resize)(struct tty_struct *tty, struct tty_struct *real_tty,
 230                                 struct winsize *ws);
 231         int (*set_termiox)(struct tty_struct *tty, struct termiox *tnew);
 232 #ifdef CONFIG_CONSOLE_POLL
 233         int (*poll_init)(struct tty_driver *driver, int line, char *options);
 234         int (*poll_get_char)(struct tty_driver *driver, int line);
 235         void (*poll_put_char)(struct tty_driver *driver, int line, char ch);
 236 #endif
 237 };
 238
 239 struct tty_driver {
 240         int     magic;          /* magic number for this structure */
 241         struct cdev cdev;
 242         struct module   *owner;
 243         const char      *driver_name;
 244         const char      *name;
 245         int     name_base;      /* offset of printed name */
 246         int     major;          /* major device number */
 247         int     minor_start;    /* start of minor device number */
 248         int     minor_num;      /* number of *possible* devices */
 249         int     num;            /* number of devices allocated */
 250         short   type;           /* type of tty driver */
 251         short   subtype;        /* subtype of tty driver */
 252         struct ktermios init_termios; /* Initial termios */
 253         int     flags;          /* tty driver flags */
 254         int     refcount;       /* for loadable tty drivers */
 255         struct proc_dir_entry *proc_entry; /* /proc fs entry */
 256         struct tty_driver *other; /* only used for the PTY driver */
 257
 258         /*
 259          * Pointer to the tty data structures
 260          */
 261         struct tty_struct **ttys;
 262         struct ktermios **termios;
 263         struct ktermios **termios_locked;
 264         void *driver_state;
 265
 266         /*
 267          * Driver methods
 268          */
 269
 270         const struct tty_operations *ops;
 271         struct list_head tty_drivers;
 272 };
 273
 274 extern struct list_head tty_drivers;
 275
 276 struct tty_driver *alloc_tty_driver(int lines);
 277 void put_tty_driver(struct tty_driver *driver);
 278 void tty_set_operations(struct tty_driver *driver,
 279                         const struct tty_operations *op);
 280 extern struct tty_driver *tty_find_polling_driver(char *name, int *line);
 281
 282 /* tty driver magic number */
 283 #define TTY_DRIVER_MAGIC                0x5402
 284
 285 /*
 286  * tty driver flags
 287  *
 288  * TTY_DRIVER_RESET_TERMIOS --- requests the tty layer to reset the
 289  *      termios setting when the last process has closed the device.
 290  *      Used for PTY's, in particular.
 291  *
 292  * TTY_DRIVER_REAL_RAW --- if set, indicates that the driver will
 293  *      guarantee never not to set any special character handling
 294  *      flags if ((IGNBRK || (!BRKINT && !PARMRK)) && (IGNPAR ||
 295  *      !INPCK)).  That is, if there is no reason for the driver to
 296  *      send notifications of parity and break characters up to the
 297  *      line driver, it won't do so.  This allows the line driver to
 298  *      optimize for this case if this flag is set.  (Note that there
 299  *      is also a promise, if the above case is true, not to signal
 300  *      overruns, either.)
 301  *
 302  * TTY_DRIVER_DYNAMIC_DEV --- if set, the individual tty devices need
 303  *      to be registered with a call to tty_register_driver() when the
 304  *      device is found in the system and unregistered with a call to
 305  *      tty_unregister_device() so the devices will be show up
 306  *      properly in sysfs.  If not set, driver->num entries will be
 307  *      created by the tty core in sysfs when tty_register_driver() is
 308  *      called.  This is to be used by drivers that have tty devices
 309  *      that can appear and disappear while the main tty driver is
 310  *      registered with the tty core.
 311  *
 312  * TTY_DRIVER_DEVPTS_MEM -- don't use the standard arrays, instead
 313  *      use dynamic memory keyed through the devpts filesystem.  This
 314  *      is only applicable to the pty driver.
 315  *
 316  * TTY_DRIVER_HARDWARE_BREAK -- hardware handles break signals. Pass
 317  *      the requested timeout to the caller instead of using a simple
 318  *      on/off interface.
 319  *
 320  */
 321 #define TTY_DRIVER_INSTALLED            0x0001
 322 #define TTY_DRIVER_RESET_TERMIOS        0x0002
 323 #define TTY_DRIVER_REAL_RAW             0x0004
 324 #define TTY_DRIVER_DYNAMIC_DEV          0x0008
 325 #define TTY_DRIVER_DEVPTS_MEM           0x0010
 326 #define TTY_DRIVER_HARDWARE_BREAK       0x0020
 327
 328 /* tty driver types */
 329 #define TTY_DRIVER_TYPE_SYSTEM          0x0001
 330 #define TTY_DRIVER_TYPE_CONSOLE         0x0002
 331 #define TTY_DRIVER_TYPE_SERIAL          0x0003
 332 #define TTY_DRIVER_TYPE_PTY             0x0004
 333 #define TTY_DRIVER_TYPE_SCC             0x0005  /* scc driver */
 334 #define TTY_DRIVER_TYPE_SYSCONS         0x0006
 335
 336 /* system subtypes (magic, used by tty_io.c) */
 337 #define SYSTEM_TYPE_TTY                 0x0001
 338 #define SYSTEM_TYPE_CONSOLE             0x0002
 339 #define SYSTEM_TYPE_SYSCONS             0x0003
 340 #define SYSTEM_TYPE_SYSPTMX             0x0004
 341
 342 /* pty subtypes (magic, used by tty_io.c) */
 343 #define PTY_TYPE_MASTER                 0x0001
 344 #define PTY_TYPE_SLAVE                  0x0002
 345
 346 /* serial subtype definitions */
 347 #define SERIAL_TYPE_NORMAL      1
 348
 349 #endif /* #ifdef _LINUX_TTY_DRIVER_H */