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