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TTYCTRL

Tty control structure

Synopsis:

typedef struct chario_entry {
	dispatch_t		*dpp;
	int				coid;
	int				timerid;
	unsigned		max_devs;
	unsigned		num_devs;
	struct sigevent	event;
	struct sigevent	timer;
	struct ttydev_entry	*timer_list;
	unsigned		num_events;
	struct ttydev_entry	**event_queue;
	intrspin_t		lock;
} TTYCTRL;

Description:

A character driver shares the TTYCTRL with the io-char library. This structure is used to coordinate events, timers, and so on.

The members include:

dpp

A dispatch handle, returned by dispatch_create(). Used only by io-char.

coid

The connection ID. Used only by io-char.

timerid

The timer ID. Used only by io-char.

max_devs

Used by io-char and the driver to define the maximum number of devices supported.

num_devs

Used only by io-char to define the current number of devices supported.

event

Used by the driver to send pulse events to io-char's event handler. Flags are used to indicate which event occurred. The driver must send the event to io-char.

The following events are currently defined:

• EVENT_QUEUED -- there is an event queued.
• EVENT_SIGBRK -- POSIX job control for SIGBRK sends SIGINT. This event is called by TTI_BREAK, so the driver probably doesn't need to do this.
• EVENT_SIGHUP -- POSIX job control, TTI_HANGUP.
• EVENT_TTO -- not used.
• EVENT_READ -- used by io-char.
• EVENT_WRITE -- called by the driver. Unblock an application waiting to write when the output buffer has room to take characters.
• EVENT_DRAIN -- called by the driver. The output buffer has drained (unblock someone waiting on the device to drain.)
• EVENT_TIMEOUT -- used by io-char.
• EVENT_NOTIFY_INPUT -- input notification (used by io-char). See the notify entry in TTYDEV.
• EVENT_NOTIFY_OUTPUT -- output notification (used by io-char. See the notify entry in TTYDEV.
• EVENT_NOTIFY_OBAND -- driver notifies io-char if out-of-band data is available.
• EVENT_CARRIER -- generated by TTI_CARRIER.
• EVENT_SIGQUIT -- job control, generated by TTI_QUIT to notify that a QUIT character has been received.
• EVENT_SIGSUP -- job control, generated by TTI_SUSP to notify that a SUSP character has been received.

timer

A pulse to call the timer handler. Used only by io-char.

timer_list

Used only by io-char, it provides a list of active timers.

num_events

Used by io-char and the driver, it displays the current number of events for processing.

event_queue

An array of TTYDEV structures used by io-char and the driver to queue events.

lock

A lock used to control access to this structure. Use the dev_lock() and dev_unlock() macros to access this member.

Classification:

Photon

See also:

TTYDEV