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event.c revision 1.1 
      1  1.1  mw /*
      2  1.1  mw  * Copyright (c) 1992, 1993
      3  1.1  mw  *	The Regents of the University of California.  All rights reserved.
      4  1.1  mw  *
      5  1.1  mw  * This software was developed by the Computer Systems Engineering group
      6  1.1  mw  * at Lawrence Berkeley Laboratory under DARPA contract BG 91-66 and
      7  1.1  mw  * contributed to Berkeley.
      8  1.1  mw  *
      9  1.1  mw  * All advertising materials mentioning features or use of this software
     10  1.1  mw  * must display the following acknowledgement:
     11  1.1  mw  *	This product includes software developed by the University of
     12  1.1  mw  *	California, Lawrence Berkeley Laboratory.
     13  1.1  mw  *
     14  1.1  mw  * Redistribution and use in source and binary forms, with or without
     15  1.1  mw  * modification, are permitted provided that the following conditions
     16  1.1  mw  * are met:
     17  1.1  mw  * 1. Redistributions of source code must retain the above copyright
     18  1.1  mw  *    notice, this list of conditions and the following disclaimer.
     19  1.1  mw  * 2. Redistributions in binary form must reproduce the above copyright
     20  1.1  mw  *    notice, this list of conditions and the following disclaimer in the
     21  1.1  mw  *    documentation and/or other materials provided with the distribution.
     22  1.1  mw  * 3. All advertising materials mentioning features or use of this software
     23  1.1  mw  *    must display the following acknowledgement:
     24  1.1  mw  *	This product includes software developed by the University of
     25  1.1  mw  *	California, Berkeley and its contributors.
     26  1.1  mw  * 4. Neither the name of the University nor the names of its contributors
     27  1.1  mw  *    may be used to endorse or promote products derived from this software
     28  1.1  mw  *    without specific prior written permission.
     29  1.1  mw  *
     30  1.1  mw  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
     31  1.1  mw  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
     32  1.1  mw  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
     33  1.1  mw  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
     34  1.1  mw  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
     35  1.1  mw  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
     36  1.1  mw  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
     37  1.1  mw  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
     38  1.1  mw  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
     39  1.1  mw  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
     40  1.1  mw  * SUCH DAMAGE.
     41  1.1  mw  *
     42  1.1  mw  *	@(#)event.c	8.1 (Berkeley) 6/11/93
     43  1.1  mw  *
     44  1.1  mw  * from: Header: event.c,v 1.5 92/11/26 01:10:44 torek Exp  (LBL)
     45  1.1  mw  * $Id: event.c,v 1.1 1994/01/26 21:05:41 mw Exp $
     46  1.1  mw  */
     47  1.1  mw 
     48  1.1  mw /*
     49  1.1  mw  * Internal `Firm_event' interface for the keyboard and mouse drivers.
     50  1.1  mw  */
     51  1.1  mw 
     52  1.1  mw #include "param.h"
     53  1.1  mw #include "fcntl.h"
     54  1.1  mw #include "malloc.h"
     55  1.1  mw #include "proc.h"
     56  1.1  mw #include "systm.h"
     57  1.1  mw #include "vnode.h"
     58  1.1  mw 
     59  1.1  mw #include "vuid_event.h"
     60  1.1  mw #include "event_var.h"
     61  1.1  mw 
     62  1.1  mw /*
     63  1.1  mw  * Initialize a firm_event queue.
     64  1.1  mw  */
     65  1.1  mw void
     66  1.1  mw ev_init(ev)
     67  1.1  mw 	register struct evvar *ev;
     68  1.1  mw {
     69  1.1  mw 
     70  1.1  mw 	ev->ev_get = ev->ev_put = 0;
     71  1.1  mw 	ev->ev_q = malloc((u_long)EV_QSIZE * sizeof(struct firm_event),
     72  1.1  mw 	    M_DEVBUF, M_WAITOK);
     73  1.1  mw 	bzero((caddr_t)ev->ev_q, EV_QSIZE * sizeof(struct firm_event));
     74  1.1  mw }
     75  1.1  mw 
     76  1.1  mw /*
     77  1.1  mw  * Tear down a firm_event queue.
     78  1.1  mw  */
     79  1.1  mw void
     80  1.1  mw ev_fini(ev)
     81  1.1  mw 	register struct evvar *ev;
     82  1.1  mw {
     83  1.1  mw 
     84  1.1  mw 	free(ev->ev_q, M_DEVBUF);
     85  1.1  mw }
     86  1.1  mw 
     87  1.1  mw /*
     88  1.1  mw  * User-level interface: read, select.
     89  1.1  mw  * (User cannot write an event queue.)
     90  1.1  mw  */
     91  1.1  mw int
     92  1.1  mw ev_read(ev, uio, flags)
     93  1.1  mw 	register struct evvar *ev;
     94  1.1  mw 	struct uio *uio;
     95  1.1  mw 	int flags;
     96  1.1  mw {
     97  1.1  mw 	int s, n, cnt, error;
     98  1.1  mw 
     99  1.1  mw 	/*
    100  1.1  mw 	 * Make sure we can return at least 1.
    101  1.1  mw 	 */
    102  1.1  mw 	if (uio->uio_resid < sizeof(struct firm_event))
    103  1.1  mw 		return (EMSGSIZE);	/* ??? */
    104  1.1  mw 	s = splev();
    105  1.1  mw 	while (ev->ev_get == ev->ev_put) {
    106  1.1  mw 		if (flags & IO_NDELAY) {
    107  1.1  mw 			splx(s);
    108  1.1  mw 			return (EWOULDBLOCK);
    109  1.1  mw 		}
    110  1.1  mw 		ev->ev_wanted = 1;
    111  1.1  mw 		error = tsleep((caddr_t)ev, PEVENT | PCATCH, "firm_event", 0);
    112  1.1  mw 		if (error) {
    113  1.1  mw 			splx(s);
    114  1.1  mw 			return (error);
    115  1.1  mw 		}
    116  1.1  mw 	}
    117  1.1  mw 	/*
    118  1.1  mw 	 * Move firm_events from tail end of queue (there is at least one
    119  1.1  mw 	 * there).
    120  1.1  mw 	 */
    121  1.1  mw 	if (ev->ev_put < ev->ev_get)
    122  1.1  mw 		cnt = EV_QSIZE - ev->ev_get;	/* events in [get..QSIZE) */
    123  1.1  mw 	else
    124  1.1  mw 		cnt = ev->ev_put - ev->ev_get;	/* events in [get..put) */
    125  1.1  mw 	splx(s);
    126  1.1  mw 	n = howmany(uio->uio_resid, sizeof(struct firm_event));
    127  1.1  mw 	if (cnt > n)
    128  1.1  mw 		cnt = n;
    129  1.1  mw 	error = uiomove((caddr_t)&ev->ev_q[ev->ev_get],
    130  1.1  mw 	    cnt * sizeof(struct firm_event), uio);
    131  1.1  mw 	n -= cnt;
    132  1.1  mw 	/*
    133  1.1  mw 	 * If we do not wrap to 0, used up all our space, or had an error,
    134  1.1  mw 	 * stop.  Otherwise move from front of queue to put index, if there
    135  1.1  mw 	 * is anything there to move.
    136  1.1  mw 	 */
    137  1.1  mw 	if ((ev->ev_get = (ev->ev_get + cnt) % EV_QSIZE) != 0 ||
    138  1.1  mw 	    n == 0 || error || (cnt = ev->ev_put) == 0)
    139  1.1  mw 		return (error);
    140  1.1  mw 	if (cnt > n)
    141  1.1  mw 		cnt = n;
    142  1.1  mw 	error = uiomove((caddr_t)&ev->ev_q[0],
    143  1.1  mw 	    cnt * sizeof(struct firm_event), uio);
    144  1.1  mw 	ev->ev_get = cnt;
    145  1.1  mw 	return (error);
    146  1.1  mw }
    147  1.1  mw 
    148  1.1  mw int
    149  1.1  mw ev_select(ev, rw, p)
    150  1.1  mw 	register struct evvar *ev;
    151  1.1  mw 	int rw;
    152  1.1  mw 	struct proc *p;
    153  1.1  mw {
    154  1.1  mw 	int s = splev();
    155  1.1  mw 
    156  1.1  mw 	switch (rw) {
    157  1.1  mw 
    158  1.1  mw 	case FREAD:
    159  1.1  mw 		/* succeed if there is something to read */
    160  1.1  mw 		if (ev->ev_get != ev->ev_put) {
    161  1.1  mw 			splx(s);
    162  1.1  mw 			return (1);
    163  1.1  mw 		}
    164  1.1  mw 		selrecord(p, &ev->ev_sel);
    165  1.1  mw 		break;
    166  1.1  mw 
    167  1.1  mw 	case FWRITE:
    168  1.1  mw 		return (1);	/* always fails => never blocks */
    169  1.1  mw 	}
    170  1.1  mw 	splx(s);
    171  1.1  mw 	return (0);
    172  1.1  mw }
    173