/*      $NetBSD: interrupt.c,v 1.8 2019/12/11 16:16:13 tsutsui Exp $    */

/*-
 * Copyright (c) 2010 The NetBSD Foundation, Inc.
 * All rights reserved.
 *
 * This code was written by Alessandro Forin and Neil Pittman
 * at Microsoft Research and contributed to The NetBSD Foundation
 * by Microsoft Corporation.
 *
 * 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.
 */

#include <sys/cdefs.h>
__KERNEL_RCSID(0, "$NetBSD: interrupt.c,v 1.8 2019/12/11 16:16:13 tsutsui Exp $");

#include <sys/param.h>
#include <sys/device.h>
#include <sys/proc.h>

#include <uvm/uvm_extern.h>

#include <mips/psl.h>

#include <machine/locore.h>
#include <machine/autoconf.h>
#include <machine/sysconf.h>
#include <machine/intr.h>
#include <machine/emipsreg.h>

struct intrhand          intrtab[MAX_DEV_NCOOKIES];

struct evcnt emips_clock_evcnt =
    EVCNT_INITIALIZER(EVCNT_TYPE_INTR, NULL, "clock", "intr");
struct evcnt emips_fpu_evcnt =
    EVCNT_INITIALIZER(EVCNT_TYPE_INTR, NULL, "fpu", "intr");
struct evcnt emips_memerr_evcnt =
    EVCNT_INITIALIZER(EVCNT_TYPE_INTR, NULL, "memerr", "intr");

static const char * const intrnames[MAX_DEV_NCOOKIES] = {
        "int-0", "int-1", "int-2", "int-3", "int-4",
        "int-5", "int-6", "int-7", "int-8", "int-9",
        "int-10", "int-11", "int-12", "int-13", "int-14",
        "int-15", "int-16", "int-17", "int-18", "int-19",
        "int-20", "int-21`", "int-22", "int-23", "int-24",
        "int-25", "int-26", "int-27", "int-28", "int-29",
        "int-30", "int-31"
};

void
intr_init(void)
{
        int i;

        for (i = 0; i < MAX_DEV_NCOOKIES; i++) {
                evcnt_attach_dynamic(&intrtab[i].ih_count,
                    EVCNT_TYPE_INTR, NULL, "emips", intrnames[i]);
        }

        /* I am trying to make this standard so its here. Bah. */
        struct tlbmask tlb;

        /* This is ugly but efficient. Sigh. */
#define TheAic ((struct _Aic *)INTERRUPT_CONTROLLER_DEFAULT_ADDRESS)

        tlb.tlb_hi = INTERRUPT_CONTROLLER_DEFAULT_ADDRESS;
        tlb.tlb_lo0 = INTERRUPT_CONTROLLER_DEFAULT_ADDRESS | 0xf02;
        tlb_write_entry(4, &tlb);

        tlb.tlb_hi = TIMER_DEFAULT_ADDRESS;
        tlb.tlb_lo0 = TIMER_DEFAULT_ADDRESS | 0xf02;
        tlb_write_entry(5, &tlb);
}

/*
 * emips uses one line for all I/O interrupts (0x8000).
 */
void
cpu_intr(int ppl, vaddr_t pc, uint32_t status)
{
        uint32_t ipending;
        int ipl;

        curcpu()->ci_data.cpu_nintr++;

#if 0
        /*
         * According to Giano simulator sources (Cpus/mips_cpu.cpp),
         * interrupt register bits in CAUSE register are updated
         * only when the exception is triggered. This means checking
         * CAUSE register via splintr() in a while loop in this
         * interrupt handler doesn't work as expected on Giano.
         *
         * I don't know whether the real FPGA eMIPS has the same
         * design as the Giano simulator, but for now I'd like to
         * choose 'call only one handler per each interrupt' strategy,
         * as the original NetBSD/emips implementation.
         */
        while (ppl < (ipl = splintr(&ipending))) {
                splx(ipl);
                /* device interrupts */
                if (ipending & MIPS_INT_MASK_5) {
                        (*platform.iointr)(status, pc, ipending);
                }
                (void)splhigh();
        }
#else
        ipl = splintr(&ipending);
        __USE(ipl);
        /* device interrupts */
        if (ipending & MIPS_INT_MASK_5) {
                (*platform.iointr)(status, pc, ipending);
        }
#endif
}

/*
 * Interrupt dispatcher for standard AIC-style interrupt controller
 */
void
emips_aic_intr(uint32_t status, vaddr_t pc, uint32_t ipending)
{
        struct clockframe cf;

        cf.pc = pc;
        cf.sr = status;
        cf.intr = (curcpu()->ci_idepth > 1);

        ipending = TheAic->IrqStatus;

        while (ipending) {
                /* Take one (most likely, the only one) */
                int index = ffs(ipending) - 1;
                ipending &= ~(1 << index);

                intrtab[index].ih_count.ev_count++;
                (*intrtab[index].ih_func)(intrtab[index].ih_arg, &cf);
        }
}


void
emips_intr_establish(device_t dev, void *cookie, int level,
        int (*handler) (void *, void *), void *arg)
{
        int index = (int) cookie;

        /*
         * First disable that interrupt source, in case it was enabled.
         * This prevents us from getting very confused with ISRs and arguments.
         */
        TheAic->IrqEnableClear = 1 << index;
    
        /* Second, the argument & isr.  */
        intrtab[index].ih_func = handler;
        intrtab[index].ih_arg = arg;

        /* Third, enable and done.  */
        TheAic->IrqEnable = 1 << index;
}