/*      $NetBSD: event.c,v 1.26 2021/09/26 01:16:09 thorpej Exp $       */

/*
 * Copyright (c) 1992, 1993
 *      The Regents of the University of California.  All rights reserved.
 *
 * This software was developed by the Computer Systems Engineering group
 * at Lawrence Berkeley Laboratory under DARPA contract BG 91-66 and
 * contributed to Berkeley.
 *
 * All advertising materials mentioning features or use of this software
 * must display the following acknowledgement:
 *      This product includes software developed by the University of
 *      California, Lawrence Berkeley Laboratory.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 * 3. Neither the name of the University nor the names of its contributors
 *    may be used to endorse or promote products derived from this software
 *    without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 *
 *      @(#)event.c     8.1 (Berkeley) 6/11/93
 */

/*
 * Internal `Firm_event' interface for the keyboard and mouse drivers.
 */

#include <sys/cdefs.h>
__KERNEL_RCSID(0, "$NetBSD: event.c,v 1.26 2021/09/26 01:16:09 thorpej Exp $");

#include <sys/param.h>
#include <sys/fcntl.h>
#include <sys/malloc.h>
#include <sys/proc.h>
#include <sys/systm.h>
#include <sys/vnode.h>
#include <sys/select.h>
#include <sys/poll.h>

#include <dev/sun/vuid_event.h>
#include <dev/sun/event_var.h>

int (*ev_out32_hook)(struct firm_event *, int, struct uio *);

/*
 * Initialize a firm_event queue.
 */
void
ev_init(struct evvar *ev)
{

        ev->ev_get = ev->ev_put = 0;
        ev->ev_q = malloc((u_long)EV_QSIZE * sizeof(struct firm_event),
            M_DEVBUF, M_WAITOK|M_ZERO);
        selinit(&ev->ev_sel);
}

/*
 * Tear down a firm_event queue.
 */
void
ev_fini(struct evvar *ev)
{

        seldestroy(&ev->ev_sel);
        free(ev->ev_q, M_DEVBUF);
}

/*
 * User-level interface: read, select.
 * (User cannot write an event queue.)
 */
int
ev_read(struct evvar *ev, struct uio *uio, int flags)
{
        int s, n, cnt, error;

        /*
         * Make sure we can return at least 1.
         */
        if (uio->uio_resid < sizeof(struct firm_event))
                return (EMSGSIZE);      /* ??? */
        s = splev();
        while (ev->ev_get == ev->ev_put) {
                if (flags & IO_NDELAY) {
                        splx(s);
                        return (EWOULDBLOCK);
                }
                ev->ev_wanted = 1;
                error = tsleep((void *)ev, PEVENT | PCATCH, "firm_event", 0);
                if (error) {
                        splx(s);
                        return (error);
                }
        }
        /*
         * Move firm_events from tail end of queue (there is at least one
         * there).
         */
        if (ev->ev_put < ev->ev_get)
                cnt = EV_QSIZE - ev->ev_get;    /* events in [get..QSIZE) */
        else
                cnt = ev->ev_put - ev->ev_get;  /* events in [get..put) */
        splx(s);
        n = howmany(uio->uio_resid, sizeof(struct firm_event));
        if (cnt > n)
                cnt = n;
        if ((curproc->p_flag & PK_32) && ev_out32_hook != NULL)
                error = (*ev_out32_hook)(&ev->ev_q[ev->ev_get], cnt, uio);
        else
                error = uiomove((void *)&ev->ev_q[ev->ev_get],
                    cnt * sizeof(struct firm_event), uio);
        n -= cnt;
        /*
         * If we do not wrap to 0, used up all our space, or had an error,
         * stop.  Otherwise move from front of queue to put index, if there
         * is anything there to move.
         */
        if ((ev->ev_get = (ev->ev_get + cnt) % EV_QSIZE) != 0 ||
            n == 0 || error || (cnt = ev->ev_put) == 0)
                return (error);
        if (cnt > n)
                cnt = n;
        if ((curproc->p_flag & PK_32) && ev_out32_hook != NULL)
                error = (*ev_out32_hook)(&ev->ev_q[0], cnt, uio);
        else
                error = uiomove((void *)&ev->ev_q[0],
            cnt * sizeof(struct firm_event), uio);
        ev->ev_get = cnt;
        return (error);
}

int
ev_poll(struct evvar *ev, int events, struct lwp *l)
{
        int s = splev(), revents = 0;

        if (events & (POLLIN | POLLRDNORM)) {
                if (ev->ev_get == ev->ev_put)
                        selrecord(l, &ev->ev_sel);
                else
                        revents |= events & (POLLIN | POLLRDNORM);
        }
        revents |= events & (POLLOUT | POLLWRNORM);

        splx(s);
        return (revents);
}

static void
filt_evrdetach(struct knote *kn)
{
        struct evvar *ev = kn->kn_hook;
        int s;

        s = splev();
        selremove_knote(&ev->ev_sel, kn);
        splx(s);
}

static int
filt_evread(struct knote *kn, long hint)
{
        struct evvar *ev = kn->kn_hook;

        if (ev->ev_get == ev->ev_put)
                return (0);

        if (ev->ev_get < ev->ev_put)
                kn->kn_data = ev->ev_put - ev->ev_get;
        else
                kn->kn_data = (EV_QSIZE - ev->ev_get) +
                    ev->ev_put;

        kn->kn_data *= sizeof(struct firm_event);

        return (1);
}

static const struct filterops ev_filtops = {
        .f_flags = FILTEROP_ISFD,
        .f_attach = NULL,
        .f_detach = filt_evrdetach,
        .f_event = filt_evread,
};

int
ev_kqfilter(struct evvar *ev, struct knote *kn)
{
        int s;

        switch (kn->kn_filter) {
        case EVFILT_READ:
                kn->kn_fop = &ev_filtops;
                break;

        default:
                return (EINVAL);
        }

        kn->kn_hook = ev;

        s = splev();
        selrecord_knote(&ev->ev_sel, kn);
        splx(s);

        return (0);
}