/*      $NetBSD: intr.c,v 1.9 2020/12/19 21:27:52 thorpej Exp $ */

/*-
 * Copyright (C) 2005 NONAKA Kimihiro <nonaka@netbsd.org>
 * 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.
 *
 * 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.
 */

#include <sys/cdefs.h>
__KERNEL_RCSID(0, "$NetBSD: intr.c,v 1.9 2020/12/19 21:27:52 thorpej Exp $");

#include <sys/param.h>
#include <sys/systm.h>
#include <sys/kernel.h>
#include <sys/kmem.h>
#include <sys/device.h>

#include <sh3/exception.h>

#include <machine/intr.h>

#define _N_EXTINTR              8

#define LANDISK_INTEN           0xb0000005
#define INTEN_ALL_MASK          0x00

struct intrhand {
        int     (*ih_fun)(void *);
        void    *ih_arg;
        struct  intrhand *ih_next;
        int     ih_enable;
        int     ih_level;
        int     ih_irq;
        struct evcnt ih_evcnt;
};

struct extintr_handler {
        int             (*eih_func)(void *eih_arg);
        void            *eih_arg;
        struct intrhand *eih_ih;
        int             eih_nih;
};

static struct extintr_handler extintr_handler[_N_EXTINTR];

static const char *extintr_names[_N_EXTINTR] = {
        "irq5", "irq6", "irq7", "irq8",
        "irq9", "irq10", "irq11", "irq12"
};

static int fakeintr(void *arg);
static int extintr_intr_handler(void *arg);

void
intc_intr(int ssr, int spc, int ssp)
{
        struct intc_intrhand *ih;
        struct clockframe cf;
        int evtcode;

        curcpu()->ci_data.cpu_nintr++;

        evtcode = _reg_read_4(SH4_INTEVT);
        ih = EVTCODE_IH(evtcode);
        KDASSERT(ih->ih_func);

        switch (evtcode) {
#if 0
#define IRL(irq)        (0x200 + ((irq) << 5))
        case IRL(5): case IRL(6): case IRL(7): case IRL(8):
        case IRL(9): case IRL(10): case IRL(11): case IRL(12):
        {
                int level;
                uint8_t inten, bit;

                bit = 1 << (EVTCODE_TO_MAP_INDEX(evtcode) - 5);
                inten = _reg_read_1(LANDISK_INTEN);
                _reg_write_1(LANDISK_INTEN, inten & ~bit);
                level = (_IPL_NSOFT + 1) << 4;  /* disable softintr */
                ssr &= 0xf0;
                if (level < ssr)
                        level = ssr;
                (void)_cpu_intr_resume(level);
                (*ih->ih_func)(ih->ih_arg);
                _reg_write_1(LANDISK_INTEN, inten);
                break;
        }
#endif
        default:
                (void)_cpu_intr_resume(ih->ih_level);
                (*ih->ih_func)(ih->ih_arg);
                break;

        case SH_INTEVT_TMU0_TUNI0:
                (void)_cpu_intr_resume(ih->ih_level);
                cf.spc = spc;
                cf.ssr = ssr;
                cf.ssp = ssp;
                (*ih->ih_func)(&cf);
                break;

        case SH_INTEVT_NMI:
                printf("NMI ignored.\n");
                break;
        }
}

void
intr_init(void)
{

        _reg_write_1(LANDISK_INTEN, INTEN_ALL_MASK);
}

void *
extintr_establish(int irq, int level, int (*ih_fun)(void *), void *ih_arg)
{
        static struct intrhand fakehand = {fakeintr};
        struct extintr_handler *eih;
        struct intrhand **p, *q, *ih;
        const char *name;
        int evtcode;
        int s;

        KDASSERT(irq >= 5 && irq <= 12);

        ih = kmem_alloc(sizeof(*ih), KM_SLEEP);

        s = _cpu_intr_suspend();

        switch (level) {
        default:
#if defined(DEBUG)
                panic("extintr_establish: unknown level %d", level);
                /*NOTREACHED*/
#endif
        case IPL_VM:
                break;
        }

        eih = &extintr_handler[irq - 5];
        if (eih->eih_func == NULL) {
                evtcode = 0x200 + (irq << 5);
                eih->eih_func = intc_intr_establish(evtcode, IST_LEVEL, level,
                    extintr_intr_handler, eih);
        }

        /*
         * Figure out where to put the handler.
         * This is O(N^2), but we want to preserve the order, and N is
         * generally small.
         */
        for (p = &eih->eih_ih; (q = *p) != NULL; p = &q->ih_next)
                continue;

        /*
         * Actually install a fake handler momentarily, since we might be doing
         * this with interrupts enabled and don't want the real routine called
         * until masking is set up.
         */
        fakehand.ih_level = level;
        *p = &fakehand;

        /*
         * Poke the real handler in now.
         */
        memset(ih, 0, sizeof(*ih));
        ih->ih_fun = ih_fun;
        ih->ih_arg = ih_arg;
        ih->ih_next = NULL;
        ih->ih_enable = 1;
        ih->ih_level = level;
        ih->ih_irq = irq - 5;
        name = extintr_names[irq - 5];
        evcnt_attach_dynamic(&ih->ih_evcnt, EVCNT_TYPE_INTR,
            NULL, "ext", name);
        *p = ih;

        if (++eih->eih_nih == 1) {
                /* Unmask interrupt */
                _reg_bset_1(LANDISK_INTEN, (1 << (irq - 5)));
        }

        splx(s);

        return (ih);
}

void
extintr_disestablish(void *aux)
{
        struct intrhand *ih = aux;
        struct intrhand **p, *q;
        struct extintr_handler *eih;
        int irq;
        int s;

        KDASSERT(ih != NULL);

        s = _cpu_intr_suspend();

        irq = ih->ih_irq;
        eih = &extintr_handler[irq];

        /*
         * Remove the handler from the chain.
         * This is O(n^2), too.
         */
        for (p = &eih->eih_ih; (q = *p) != NULL && q != ih; p = &q->ih_next)
                continue;
        if (q == NULL)
                panic("extintr_disestablish: handler not registered");

        *p = q->ih_next;

        evcnt_detach(&ih->ih_evcnt);

        kmem_free((void *)ih, sizeof(*ih));

        if (--eih->eih_nih == 0) {
                intc_intr_disestablish(eih->eih_func);

                /* Mask interrupt */
                _reg_bclr_1(LANDISK_INTEN, (1 << irq));
        }

        splx(s);
}

void
extintr_enable(void *aux)
{
        struct intrhand *ih = aux;
        struct intrhand *p, *q __debugused;
        struct extintr_handler *eih;
        int irq;
        int cnt;
        int s;

        KDASSERT(ih != NULL);

        s = _cpu_intr_suspend();

        irq = ih->ih_irq;
        KDASSERT(irq >= 0 && irq < 8);
        eih = &extintr_handler[irq];
        for (cnt = 0, p = eih->eih_ih, q = NULL; p != NULL; p = p->ih_next) {
                if (p->ih_enable) {
                        cnt++;
                }
                if (p == ih) {
                        q = p;
                        p->ih_enable = 1;
                }
        }
        KDASSERT(q != NULL);

        if (cnt == 0) {
                /* Unmask interrupt */
                _reg_bset_1(LANDISK_INTEN, (1 << irq));
        }

        splx(s);
}

void
extintr_disable(void *aux)
{
        struct intrhand *ih = aux;
        struct intrhand *p, *q __debugused;
        struct extintr_handler *eih;
        int irq;
        int cnt;
        int s;

        KDASSERT(ih != NULL);

        s = _cpu_intr_suspend();

        irq = ih->ih_irq;
        KDASSERT(irq >= 0 && irq < 8);
        eih = &extintr_handler[irq];
        for (cnt = 0, p = eih->eih_ih, q = NULL; p != NULL; p = p->ih_next) {
                if (p == ih) {
                        q = p;
                        p->ih_enable = 0;
                }
                if (!ih->ih_enable) {
                        cnt++;
                }
        }
        KDASSERT(q != NULL);

        if (cnt == 0) {
                /* Mask interrupt */
                _reg_bclr_1(LANDISK_INTEN, (1 << irq));
        }

        splx(s);
}

void
extintr_disable_by_num(int irq)
{
        struct extintr_handler *eih;
        struct intrhand *ih;
        int s;

        KDASSERT(irq >= 5 && irq <= 12);

        s = _cpu_intr_suspend();
        eih = &extintr_handler[irq - 5];
        for (ih = eih->eih_ih; ih != NULL; ih = ih->ih_next) {
                ih->ih_enable = 0;
        }
        /* Mask interrupt */
        _reg_bclr_1(LANDISK_INTEN, (1 << irq));
        splx(s);
}

static int
fakeintr(void *arg)
{

        return 0;
}

static int
extintr_intr_handler(void *arg)
{
        struct extintr_handler *eih = arg;
        struct intrhand *ih;
        int r;

        if (__predict_true(eih != NULL)) {
                for (ih = eih->eih_ih; ih != NULL; ih = ih->ih_next) {
                        if (__predict_true(ih->ih_enable)) {
                                r = (*ih->ih_fun)(ih->ih_arg);
                                if (__predict_true(r != 0)) {
                                        ih->ih_evcnt.ev_count++;
                                }
                        }
                }
                return 1;
        }
        return 0;
}