diff options
Diffstat (limited to 'include/linux/tty_driver.h')
| -rw-r--r-- | include/linux/tty_driver.h | 106 |
1 files changed, 58 insertions, 48 deletions
diff --git a/include/linux/tty_driver.h b/include/linux/tty_driver.h index 21f69aca450..59f1c0bd8f9 100644 --- a/include/linux/tty_driver.h +++ b/include/linux/tty_driver.h @@ -12,11 +12,15 @@ * This routine is called when a particular tty device is opened. * This routine is mandatory; if this routine is not filled in, * the attempted open will fail with ENODEV. + * + * Required method. * * void (*close)(struct tty_struct * tty, struct file * filp); * * This routine is called when a particular tty device is closed. * + * Required method. + * * int (*write)(struct tty_struct * tty, * const unsigned char *buf, int count); * @@ -26,7 +30,9 @@ * number of characters actually accepted for writing. This * routine is mandatory. * - * void (*put_char)(struct tty_struct *tty, unsigned char ch); + * Optional: Required for writable devices. + * + * int (*put_char)(struct tty_struct *tty, unsigned char ch); * * This routine is called by the kernel to write a single * character to the tty device. If the kernel uses this routine, @@ -34,10 +40,18 @@ * done stuffing characters into the driver. If there is no room * in the queue, the character is ignored. * + * Optional: Kernel will use the write method if not provided. + * + * Note: Do not call this function directly, call tty_put_char + * * void (*flush_chars)(struct tty_struct *tty); * * This routine is called by the kernel after it has written a * series of characters to the tty device using put_char(). + * + * Optional: + * + * Note: Do not call this function directly, call tty_driver_flush_chars * * int (*write_room)(struct tty_struct *tty); * @@ -45,6 +59,10 @@ * will accept for queuing to be written. This number is subject * to change as output buffers get emptied, or if the output flow * control is acted. + * + * Required if write method is provided else not needed. + * + * Note: Do not call this function directly, call tty_write_room * * int (*ioctl)(struct tty_struct *tty, struct file * file, * unsigned int cmd, unsigned long arg); @@ -53,28 +71,37 @@ * device-specific ioctl's. If the ioctl number passed in cmd * is not recognized by the driver, it should return ENOIOCTLCMD. * + * Optional + * * long (*compat_ioctl)(struct tty_struct *tty, struct file * file, * unsigned int cmd, unsigned long arg); * * implement ioctl processing for 32 bit process on 64 bit system + * + * Optional * * void (*set_termios)(struct tty_struct *tty, struct ktermios * old); * * This routine allows the tty driver to be notified when - * device's termios settings have changed. Note that a - * well-designed tty driver should be prepared to accept the case - * where old == NULL, and try to do something rational. + * device's termios settings have changed. + * + * Optional: Called under the termios lock + * * * void (*set_ldisc)(struct tty_struct *tty); * * This routine allows the tty driver to be notified when the * device's termios settings have changed. + * + * Optional: Called under BKL (currently) * * void (*throttle)(struct tty_struct * tty); * * This routine notifies the tty driver that input buffers for * the line discipline are close to full, and it should somehow * signal that no more characters should be sent to the tty. + * + * Optional: Always invoke via tty_throttle(); * * void (*unthrottle)(struct tty_struct * tty); * @@ -82,21 +109,33 @@ * that characters can now be sent to the tty without fear of * overrunning the input buffers of the line disciplines. * + * Optional: Always invoke via tty_unthrottle(); + * * void (*stop)(struct tty_struct *tty); * * This routine notifies the tty driver that it should stop * outputting characters to the tty device. + * + * Optional: + * + * Note: Call stop_tty not this method. * * void (*start)(struct tty_struct *tty); * * This routine notifies the tty driver that it resume sending * characters to the tty device. + * + * Optional: + * + * Note: Call start_tty not this method. * * void (*hangup)(struct tty_struct *tty); * * This routine notifies the tty driver that it should hangup the * tty device. * + * Required: + * * void (*break_ctl)(struct tty_stuct *tty, int state); * * This optional routine requests the tty driver to turn on or @@ -106,18 +145,26 @@ * * If this routine is implemented, the high-level tty driver will * handle the following ioctls: TCSBRK, TCSBRKP, TIOCSBRK, - * TIOCCBRK. Otherwise, these ioctls will be passed down to the - * driver to handle. + * TIOCCBRK. + * + * Optional: Required for TCSBRK/BRKP/etc handling. * * void (*wait_until_sent)(struct tty_struct *tty, int timeout); * * This routine waits until the device has written out all of the * characters in its transmitter FIFO. * + * Optional: If not provided the device is assumed to have no FIFO + * + * Note: Usually correct to call tty_wait_until_sent + * * void (*send_xchar)(struct tty_struct *tty, char ch); * * This routine is used to send a high-priority XON/XOFF * character to the device. + * + * Optional: If not provided then the write method is called under + * the atomic write lock to keep it serialized with the ldisc. */ #include <linux/fs.h> @@ -132,7 +179,7 @@ struct tty_operations { void (*close)(struct tty_struct * tty, struct file * filp); int (*write)(struct tty_struct * tty, const unsigned char *buf, int count); - void (*put_char)(struct tty_struct *tty, unsigned char ch); + int (*put_char)(struct tty_struct *tty, unsigned char ch); void (*flush_chars)(struct tty_struct *tty); int (*write_room)(struct tty_struct *tty); int (*chars_in_buffer)(struct tty_struct *tty); @@ -153,8 +200,6 @@ struct tty_operations { void (*send_xchar)(struct tty_struct *tty, char ch); int (*read_proc)(char *page, char **start, off_t off, int count, int *eof, void *data); - int (*write_proc)(struct file *file, const char __user *buffer, - unsigned long count, void *data); int (*tiocmget)(struct tty_struct *tty, struct file *file); int (*tiocmset)(struct tty_struct *tty, struct file *file, unsigned int set, unsigned int clear); @@ -190,48 +235,13 @@ struct tty_driver { struct tty_struct **ttys; struct ktermios **termios; struct ktermios **termios_locked; - void *driver_state; /* only used for the PTY driver */ - + void *driver_state; + /* - * Interface routines from the upper tty layer to the tty - * driver. Will be replaced with struct tty_operations. + * Driver methods */ - int (*open)(struct tty_struct * tty, struct file * filp); - void (*close)(struct tty_struct * tty, struct file * filp); - int (*write)(struct tty_struct * tty, - const unsigned char *buf, int count); - void (*put_char)(struct tty_struct *tty, unsigned char ch); - void (*flush_chars)(struct tty_struct *tty); - int (*write_room)(struct tty_struct *tty); - int (*chars_in_buffer)(struct tty_struct *tty); - int (*ioctl)(struct tty_struct *tty, struct file * file, - unsigned int cmd, unsigned long arg); - long (*compat_ioctl)(struct tty_struct *tty, struct file * file, - unsigned int cmd, unsigned long arg); - void (*set_termios)(struct tty_struct *tty, struct ktermios * old); - void (*throttle)(struct tty_struct * tty); - void (*unthrottle)(struct tty_struct * tty); - void (*stop)(struct tty_struct *tty); - void (*start)(struct tty_struct *tty); - void (*hangup)(struct tty_struct *tty); - void (*break_ctl)(struct tty_struct *tty, int state); - void (*flush_buffer)(struct tty_struct *tty); - void (*set_ldisc)(struct tty_struct *tty); - void (*wait_until_sent)(struct tty_struct *tty, int timeout); - void (*send_xchar)(struct tty_struct *tty, char ch); - int (*read_proc)(char *page, char **start, off_t off, - int count, int *eof, void *data); - int (*write_proc)(struct file *file, const char __user *buffer, - unsigned long count, void *data); - int (*tiocmget)(struct tty_struct *tty, struct file *file); - int (*tiocmset)(struct tty_struct *tty, struct file *file, - unsigned int set, unsigned int clear); -#ifdef CONFIG_CONSOLE_POLL - int (*poll_init)(struct tty_driver *driver, int line, char *options); - int (*poll_get_char)(struct tty_driver *driver, int line); - void (*poll_put_char)(struct tty_driver *driver, int line, char ch); -#endif + const struct tty_operations *ops; struct list_head tty_drivers; }; |