/*      $NetBSD: cache.c,v 1.25 2025/12/05 22:48:44 thorpej Exp $       */

/*-
 * Copyright (c) 1996 The NetBSD Foundation, Inc.
 * All rights reserved.
 *
 * This code is derived from software contributed to The NetBSD Foundation
 * by Gordon W. Ross.
 *
 * 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.
 */

/*
 * cache flush operations specific to the Sun3 custom MMU
 * all are done using writes to control space
 */

#include <sys/cdefs.h>
__KERNEL_RCSID(0, "$NetBSD: cache.c,v 1.25 2025/12/05 22:48:44 thorpej Exp $");

#include <sys/param.h>
#include <sys/systm.h>
#include <sys/proc.h>
#include <sys/queue.h>

#include <uvm/uvm_extern.h>

#include <machine/cpu.h>
#include <machine/fcode.h>
#include <machine/pte.h>
#include <machine/vmparam.h>

#include <sun3/sun3/control.h>
#include <sun3/sun3/enable.h>
#include <sun3/sun3/machdep.h>

#define CACHE_LINE      16      /* bytes */
#define VAC_FLUSH_INCR  512     /* bytes */
#define VADDR_MASK      0xfFFffFF       /* 28 bits */

static void cache_clear_tags(void);

void
cache_flush_page(vaddr_t pgva)
{
        char *va, *endva;
        int old_dfc, ctl_dfc;
        int data;

        pgva &= (VADDR_MASK & ~PGOFSET);
        pgva |= VAC_FLUSH_BASE;

        /* Set up for writes to control space. */
        __asm volatile ("movc %%dfc, %0" : "=d" (old_dfc));
        ctl_dfc = FC_CONTROL;
        __asm volatile ("movc %0, %%dfc" : : "d" (ctl_dfc));

        /* Write to control space for each cache line. */
        va = (char *) pgva;
        endva = (char *) (pgva + PAGE_SIZE);
        data = VAC_FLUSH_PAGE;

        do {
                __asm volatile ("movsl %0, %1@" : : "d" (data), "a" (va));
                va += VAC_FLUSH_INCR;
        } while (va < endva);

        /* Restore destination function code. */
        __asm volatile ("movc %0, %%dfc" : : "d" (old_dfc));
}

void
cache_flush_segment(vaddr_t sgva)
{
        char *va, *endva;
        int old_dfc, ctl_dfc;
        int data;

        sgva &= (VADDR_MASK & ~SEGOFSET);
        sgva |= VAC_FLUSH_BASE;

        /* Set up for writes to control space. */
        __asm volatile ("movc %%dfc, %0" : "=d" (old_dfc));
        ctl_dfc = FC_CONTROL;
        __asm volatile ("movc %0, %%dfc" : : "d" (ctl_dfc));

        /* Write to control space for each cache line. */
        va = (char *) sgva;
        endva = (char *) (sgva + cache_size);
        data = VAC_FLUSH_SEGMENT;

        do {
                __asm volatile ("movsl %0, %1@" : : "d" (data), "a" (va));
                va += VAC_FLUSH_INCR;
        } while (va < endva);

        /* Restore destination function code. */
        __asm volatile ("movc %0, %%dfc" : : "d" (old_dfc));
}

void
cache_flush_context(void)
{
        char *va, *endva;
        int old_dfc, ctl_dfc;
        int data;

        /* Set up for writes to control space. */
        __asm volatile ("movc %%dfc, %0" : "=d" (old_dfc));
        ctl_dfc = FC_CONTROL;
        __asm volatile ("movc %0, %%dfc" : : "d" (ctl_dfc));

        /* Write to control space for each cache line. */
        va = (char *) VAC_FLUSH_BASE;
        endva = (char *) (VAC_FLUSH_BASE + cache_size);
        data = VAC_FLUSH_CONTEXT;

        do {
                __asm volatile ("movsl %0, %1@" : : "d" (data), "a" (va));
                va += VAC_FLUSH_INCR;
        } while (va < endva);

        /* Restore destination function code. */
        __asm volatile ("movc %0, %%dfc" : : "d" (old_dfc));
}

static void
cache_clear_tags(void)
{
        char *va, *endva;
        int old_dfc, ctl_dfc;
        int data;

        /* Set up for writes to control space. */
        __asm volatile ("movc %%dfc, %0" : "=d" (old_dfc));
        ctl_dfc = FC_CONTROL;
        __asm volatile ("movc %0, %%dfc" : : "d" (ctl_dfc));

        /* Write to control space for each cache line. */
        va = (char *) VAC_CACHE_TAGS;
        endva = (char *) (VAC_CACHE_TAGS + cache_size);
        data = 0;       /* invalid tags */

        do {
                __asm volatile ("movsl %0, %1@" : : "d" (data), "a" (va));
                va += CACHE_LINE;
        } while (va < endva);

        /* Restore destination function code. */
        __asm volatile ("movc %0, %%dfc" : : "d" (old_dfc));
}

void
cache_enable(void)
{
        int enab_reg;

        if (cache_size == 0)
                return;

        /* Have to invalidate all tags before enabling the cache. */
        cache_clear_tags();

        /* OK, just set the "enable" bit. */
        enab_reg = get_control_byte(SYSTEM_ENAB);
        enab_reg |= ENA_CACHE;
        set_control_byte(SYSTEM_ENAB, enab_reg);

        /* Brag... */
        printf("cache enabled\n");
}