x68k/dev/event.c

/*        $NetBSD: event.c,v 1.20 2022/05/26 14:30:36 tsutsui 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 1.20 2022/05/26 14:30:36 tsutsui Exp $");

#include <sys/param.h>
#include <sys/fcntl.h>
#include <sys/kmem.h>
#include <sys/proc.h>
#include <sys/systm.h>
#include <sys/vnode.h>
#include <sys/select.h>
#include <sys/poll.h>
#include <sys/mutex.h>
#include <sys/condvar.h>

#include <machine/vuid_event.h>
#include <x68k/dev/event_var.h>

/*
 * Initialize a firm_event queue.
 */
void
ev_init(struct evvar *ev, const char *name, kmutex_t *mtx)
{

          ev->ev_get = ev->ev_put = 0;
          ev->ev_q = kmem_zalloc((size_t)EV_QSIZE * sizeof(struct firm_event),
              KM_SLEEP);
          selinit(&ev->ev_sel);
          ev->ev_lock = mtx;
          cv_init(&ev->ev_cv, name);
}

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

          cv_destroy(&ev->ev_cv);
          seldestroy(&ev->ev_sel);
          kmem_free(ev->ev_q, (size_t)EV_QSIZE * sizeof(struct firm_event));
}

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

          /*
           * Make sure we can return at least 1.
           */
          if (uio->uio_resid < sizeof(struct firm_event))
                    return EMSGSIZE;    /* ??? */
          mutex_enter(ev->ev_lock);
          while (ev->ev_get == ev->ev_put) {
                    if (flags & IO_NDELAY) {
                              mutex_exit(ev->ev_lock);
                              return EWOULDBLOCK;
                    }
                    ev->ev_wanted = true;
                    error = cv_wait_sig(&ev->ev_cv, ev->ev_lock);
                    if (error != 0) {
                              mutex_exit(ev->ev_lock);
                              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) */
          put = ev->ev_put;
          mutex_exit(ev->ev_lock);
          n = howmany(uio->uio_resid, sizeof(struct firm_event));
          if (cnt > n)
                    cnt = n;
          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 = put) == 0)
                    return error;
          if (cnt > n)
                    cnt = n;
          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 revents = 0;

          mutex_enter(ev->ev_lock);
          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);
          mutex_exit(ev->ev_lock);
          return revents;
}

void
ev_wakeup(struct evvar *ev)
{

          mutex_enter(ev->ev_lock);
          selnotify(&ev->ev_sel, 0, 0);
          if (ev->ev_wanted) {
                    ev->ev_wanted = false;
                    cv_signal(&ev->ev_cv);
          }
          mutex_exit(ev->ev_lock);

          if (ev->ev_async) {
                    mutex_enter(&proc_lock);
                    psignal(ev->ev_io, SIGIO);
                    mutex_exit(&proc_lock);
          }
}

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

          mutex_enter(ev->ev_lock);
          selremove_knote(&ev->ev_sel, kn);
          mutex_exit(ev->ev_lock);
}

static int
filt_evread(struct knote *kn, long hint)
{
          struct evvar *ev = kn->kn_hook;
          int rv = 1;

          mutex_enter(ev->ev_lock);
          if (ev->ev_get == ev->ev_put) {
                    rv = 0;
          } else {
                    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);
          }
          mutex_exit(ev->ev_lock);

          return rv;
}

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)
{

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

          default:
                    return EINVAL;
          }

          kn->kn_hook = ev;

          mutex_enter(ev->ev_lock);
          selrecord_knote(&ev->ev_sel, kn);
          mutex_exit(ev->ev_lock);

          return 0;
}