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