/* $NetBSD: wsevent.c,v 1.47 2021/09/26 01:16:10 thorpej Exp $ */

/*-
* Copyright (c) 2006, 2008 The NetBSD Foundation, Inc.
* All rights reserved.
*
* This code is derived from software contributed to The NetBSD Foundation
* by Julio M. Merino Vidal.
*
* 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.
*
* THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. 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 FOUNDATION 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.
*/

/*
* Copyright (c) 1996, 1997 Christopher G. Demetriou.  All rights reserved.
*
* 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. All advertising materials mentioning features or use of this software
*    must display the following acknowledgement:
*      This product includes software developed by Christopher G. Demetriou
*      for the NetBSD Project.
* 4. The name of the author may not be used to endorse or promote products
*    derived from this software without specific prior written permission
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``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 AUTHOR 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.
*/

/*
* 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 "wscons_event" queue interface for the keyboard and mouse drivers.
*/

#include <sys/cdefs.h>
__KERNEL_RCSID(0, "$NetBSD: wsevent.c,v 1.47 2021/09/26 01:16:10 thorpej Exp $");

#ifdef _KERNEL_OPT
#include "opt_compat_netbsd.h"
#include "opt_modular.h"
#endif

#include <sys/param.h>
#include <sys/kernel.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/compat_stub.h>
#include <sys/sysctl.h>

#include <dev/wscons/wsconsio.h>
#include <dev/wscons/wseventvar.h>

/*
* Size of a wsevent queue (measured in number of events).
* Should be a power of two so that `%' is fast.
* At the moment, the value below makes the queues use 2 Kbytes each; this
* value may need tuning.
*/
#define WSEVENT_QSIZE   256

#define EVSIZE(ver)     ((ver) == WSEVENT_VERSION ? \
   sizeof(struct wscons_event) : \
   sizeof(struct owscons_event))
#define EVARRAY(ev, idx) (&(ev)->q[(idx)])

static int wsevent_default_version = WSEVENT_VERSION;

/*
* Priority of code managing wsevent queues.  PWSEVENT is set just above
* PSOCK, which is just above TTIPRI, on the theory that mouse and keyboard
* `user' input should be quick.
*/
#define PWSEVENT        23
#define splwsevent()    spltty()

static void     wsevent_intr(void *);

/*
* Initialize a wscons_event queue.
*/
void
wsevent_init(struct wseventvar *ev, struct proc *p)
{

       if (ev->q != NULL) {
#ifdef DIAGNOSTIC
               printf("wsevent_init: already init\n");
#endif
               return;
       }
       /*
        * For binary compat set default version and either build with
        * COMPAT_50 or load COMPAT_50 module to include the compatibility
        * code.
        */
       if (wsevent_default_version >= 0 &&
           wsevent_default_version < WSEVENT_VERSION)
               ev->version = wsevent_default_version;
       else
               ev->version = WSEVENT_VERSION;

       ev->get = ev->put = 0;
       ev->q = kmem_alloc(WSEVENT_QSIZE * sizeof(*ev->q), KM_SLEEP);
       selinit(&ev->sel);
       ev->io = p;
       ev->sih = softint_establish(SOFTINT_MPSAFE | SOFTINT_CLOCK,
           wsevent_intr, ev);
}

/*
* Tear down a wscons_event queue.
*/
void
wsevent_fini(struct wseventvar *ev)
{
       if (ev->q == NULL) {
#ifdef DIAGNOSTIC
               printf("wsevent_fini: already fini\n");
#endif
               return;
       }
       seldestroy(&ev->sel);
       kmem_free(ev->q, WSEVENT_QSIZE * sizeof(*ev->q));
       ev->q = NULL;
       softint_disestablish(ev->sih);
}

static int
wsevent_copyout_events(const struct wscons_event *events, int cnt,
   struct uio *uio, int ver)
{
       int error;

       switch (ver) {
       case 0:
               MODULE_HOOK_CALL(wscons_copyout_events_50_hook,
                   (events, cnt, uio), enosys(), error);
               if (error == ENOSYS)
                       error = EINVAL;
               return error;
       case WSEVENT_VERSION:
               return uiomove(__UNCONST(events), cnt * sizeof(*events), uio);
       default:
               panic("%s: unknown version %d", __func__, ver);
       }
}

/*
* User-level interface: read, poll.
* (User cannot write an event queue.)
*/
int
wsevent_read(struct wseventvar *ev, struct uio *uio, int flags)
{
       int s, n, cnt, error;
       const int ver = ev->version;
       const size_t evsize = EVSIZE(ver);

       /*
        * Make sure we can return at least 1.
        */
       if (uio->uio_resid < evsize)
               return (EMSGSIZE);      /* ??? */
       s = splwsevent();
       while (ev->get == ev->put) {
               if (flags & IO_NDELAY) {
                       splx(s);
                       return (EWOULDBLOCK);
               }
               ev->wanted = 1;
               error = tsleep(ev, PWSEVENT | PCATCH, "wsevent_read", 0);
               if (error) {
                       splx(s);
                       return (error);
               }
       }
       /*
        * Move wscons_event from tail end of queue (there is at least one
        * there).
        */
       if (ev->put < ev->get)
               cnt = WSEVENT_QSIZE - ev->get;  /* events in [get..QSIZE) */
       else
               cnt = ev->put - ev->get;        /* events in [get..put) */
       splx(s);
       n = howmany(uio->uio_resid, evsize);
       if (cnt > n)
               cnt = n;
       error = wsevent_copyout_events(EVARRAY(ev, ev->get), cnt, uio, ver);
       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->get = (ev->get + cnt) % WSEVENT_QSIZE) != 0 ||
           n == 0 || error || (cnt = ev->put) == 0)
               return (error);
       if (cnt > n)
               cnt = n;
       error = wsevent_copyout_events(EVARRAY(ev, 0), cnt, uio, ver);
       ev->get = cnt;
       return (error);
}

int
wsevent_poll(struct wseventvar *ev, int events, struct lwp *l)
{
       int revents = 0;
       int s = splwsevent();

       if (events & (POLLIN | POLLRDNORM)) {
               if (ev->get != ev->put)
                       revents |= events & (POLLIN | POLLRDNORM);
               else
                       selrecord(l, &ev->sel);
       }

       splx(s);
       return (revents);
}

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

       s = splwsevent();
       selremove_knote(&ev->sel, kn);
       splx(s);
}

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

       if (ev->get == ev->put)
               return (0);

       if (ev->get < ev->put)
               kn->kn_data = ev->put - ev->get;
       else
               kn->kn_data = (WSEVENT_QSIZE - ev->get) + ev->put;

       kn->kn_data *= EVSIZE(ev->version);

       return (1);
}

static const struct filterops wsevent_filtops = {
       .f_flags = FILTEROP_ISFD,
       .f_attach = NULL,
       .f_detach = filt_wseventrdetach,
       .f_event = filt_wseventread,
};

int
wsevent_kqfilter(struct wseventvar *ev, struct knote *kn)
{
       int s;

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

       default:
               return (EINVAL);
       }

       kn->kn_hook = ev;

       s = splwsevent();
       selrecord_knote(&ev->sel, kn);
       splx(s);

       return (0);
}

/*
* Wakes up all listener of the 'ev' queue.
*/
void
wsevent_wakeup(struct wseventvar *ev)
{

       selnotify(&ev->sel, 0, 0);

       if (ev->wanted) {
               ev->wanted = 0;
               wakeup(ev);
       }

       if (ev->async) {
               softint_schedule(ev->sih);
       }
}

/*
* Soft interrupt handler: sends signal to async proc.
*/
static void
wsevent_intr(void *cookie)
{
       struct wseventvar *ev;

       ev = cookie;

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

/*
* Injects the set of events given in 'events', whose size is 'nevents',
* into the 'ev' queue.  If there is not enough free space to inject them
* all, returns ENOSPC and the queue is left intact; otherwise returns 0
* and wakes up all listeners.
*/
int
wsevent_inject(struct wseventvar *ev, struct wscons_event *events,
   size_t nevents)
{
       size_t avail, i;
       struct timespec t;

       /* Calculate number of free slots in the queue. */
       if (ev->put < ev->get)
               avail = ev->get - ev->put;
       else
               avail = WSEVENT_QSIZE - (ev->put - ev->get);
       KASSERT(avail <= WSEVENT_QSIZE);

       /* Fail if there is all events will not fit in the queue. */
       if (avail < nevents)
               return ENOSPC;

       /* Use the current time for all events. */
       getnanotime(&t);

       /* Inject the events. */
       for (i = 0; i < nevents; i++) {
               struct wscons_event *we;

               we = EVARRAY(ev, ev->put);
               we->type = events[i].type;
               we->value = events[i].value;
               we->time = t;

               ev->put = (ev->put + 1) % WSEVENT_QSIZE;
       }
       wsevent_wakeup(ev);

       return 0;
}

int
wsevent_setversion(struct wseventvar *ev, int vers)
{
       if (ev == NULL)
               return EINVAL;

       switch (vers) {
       case 0:
       case WSEVENT_VERSION:
               break;
       default:
               return EINVAL;
       }

       if (vers == ev->version)
               return 0;

       ev->get = ev->put = 0;
       ev->version = vers;
       return 0;
}

SYSCTL_SETUP(sysctl_wsevent_setup, "sysctl hw.wsevent subtree setup")
{
       const struct sysctlnode *node = NULL;

       if (sysctl_createv(clog, 0, NULL, &node,
           CTLFLAG_PERMANENT,
           CTLTYPE_NODE, "wsevent", NULL,
           NULL, 0, NULL, 0,
           CTL_HW, CTL_CREATE, CTL_EOL) != 0)
               return;

       sysctl_createv(clog, 0, &node, NULL,
           CTLFLAG_READWRITE,
           CTLTYPE_INT, "default_version",
           SYSCTL_DESCR("Set default event version for compatibility"),
           NULL, 0, &wsevent_default_version, 0,
           CTL_CREATE, CTL_EOL);
}