/*
 * Copyright (c) 2006 The DragonFly Project.  All rights reserved.
 *
 * This code is derived from software contributed to The DragonFly Project
 * by Matthew Dillon <dillon@backplane.com>
 *
 * 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 DragonFly Project 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 COPYRIGHT HOLDERS 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
 * COPYRIGHT HOLDERS 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.
 */

#include <sys/types.h>
#include <sys/systm.h>
#include <sys/kernel.h>
#include <sys/malloc.h>
#include <sys/systimer.h>
#include <sys/sysctl.h>
#include <sys/signal.h>
#include <sys/interrupt.h>
#include <sys/bus.h>
#include <sys/time.h>
#include <sys/event.h>
#include <machine/cpu.h>
#include <machine/globaldata.h>
#include <machine/md_var.h>

#include <unistd.h>
#include <signal.h>
#include <stdlib.h>
#include <fcntl.h>

struct kqueue_info {
        void (*func)(void *, struct intrframe *);
        void *data;
        int fd;
};

static int KQueueFd = -1;

/*
 * Initialize kqueue based I/O
 *
 * Use SIGIO to get an immediate event when the kqueue has something waiting
 * for us.  Setup the SIGIO signal as a mailbox signal for efficiency.
 *
 * Currently only read events are supported.
 */
void
init_kqueue(void)
{
#if 0
        struct sigaction sa;
        bzero(&sa, sizeof(sa));
        /*sa.sa_mailbox = &mdcpu->gd_mailbox;*/
        sa.sa_flags = 0;
        sa.sa_handler = kqueuesig;
        sigemptyset(&sa.sa_mask);
        sigaction(SIGIO, &sa, NULL);
#endif
        KQueueFd = kqueue();
        if (fcntl(KQueueFd, F_SETOWN, getpid()) < 0)
                panic("Cannot configure kqueue for SIGIO, update your kernel");
        if (fcntl(KQueueFd, F_SETFL, O_ASYNC) < 0)
                panic("Cannot configure kqueue for SIGIO, update your kernel");
}

#if 0
/*
 * Signal handler dispatches interrupt thread.  Use interrupt #1
 */
static void
kqueuesig(int signo)
{
        signalintr(1);
}

#endif

/*
 * Generic I/O event support
 */
struct kqueue_info *
kqueue_add(int fd, void (*func)(void *, struct intrframe *), void *data)
{
        struct timespec ts = { 0, 0 };
        struct kqueue_info *info;
        struct kevent kev;

        info = kmalloc(sizeof(*info), M_DEVBUF, M_ZERO|M_INTWAIT);
        info->func = func;
        info->data = data;
        info->fd = fd;
        EV_SET(&kev, fd, EVFILT_READ, EV_ADD|EV_ENABLE|EV_CLEAR, 0, 0, info);
        if (kevent(KQueueFd, &kev, 1, NULL, 0, &ts) < 0)
                panic("kqueue: kevent() call could not add descriptor");
        return(info);
}

#if 0
/*
 * Medium resolution timer support
 */
struct kqueue_info *
kqueue_add_timer(void (*func)(void *, struct intrframe *), void *data)
{
        struct kqueue_info *info;

        info = kmalloc(sizeof(*info), M_DEVBUF, M_ZERO|M_INTWAIT);
        info->func = func;
        info->data = data;
        info->fd = (uintptr_t)info;

        return(info);
}

void
kqueue_reload_timer(struct kqueue_info *info, int ms)
{
        struct timespec ts = { 0, 0 };
        struct kevent kev;

        KKASSERT(ms > 0);

        EV_SET(&kev, info->fd, EVFILT_TIMER,
                EV_ADD|EV_ENABLE|EV_ONESHOT|EV_CLEAR, 0, (uintptr_t)ms, info);
        if (kevent(KQueueFd, &kev, 1, NULL, 0, &ts) < 0)
                panic("kqueue_reload_timer: Failed");
}
#endif

/*
 * Destroy a previously added kqueue event
 */
void
kqueue_del(struct kqueue_info *info)
{
        struct timespec ts = { 0, 0 };
        struct kevent kev;

        KKASSERT(info->fd >= 0);
        EV_SET(&kev, info->fd, EVFILT_READ, EV_DELETE, 0, 0, NULL);
        if (kevent(KQueueFd, &kev, 1, NULL, 0, &ts) < 0)
                panic("kevent: failed to delete descriptor %d", info->fd);
        info->fd = -1;
        kfree(info, M_DEVBUF);
}

/*
 * Safely called via DragonFly's normal interrupt handling mechanism.
 *
 * Calleld with the MP lock held.  Note that this is still an interrupt
 * thread context.
 */
void
kqueue_intr(struct intrframe *frame)
{
        struct timespec ts;
        struct kevent kevary[8];
        int n;
        int i;

        ts.tv_sec = 0;
        ts.tv_nsec = 0;
        do {
                n = kevent(KQueueFd, NULL, 0, kevary, 8, &ts);
                for (i = 0; i < n; ++i) {
                        struct kevent *kev = &kevary[i];
                        struct kqueue_info *info = (void *)kev->udata;

                        info->func(info->data, frame);
                }
        } while (n == 8);
}