/*
 * 86Box	A hypervisor and IBM PC system emulator that specializes in
 *		running old operating systems and software designed for IBM
 *		PC systems and compatibles from 1981 through fairly recent
 *		system designs based on the PCI bus.
 *
 *		This file is part of the 86Box distribution.
 *
 *		Implementation of the ETEQ Cheetah ET6000 chipset.
 *
 *      Authors: Tiseno100
 *
 *		Copyright 2021 Tiseno100
 *
 */

#include <stdarg.h>
#include <stdint.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <wchar.h>
#define HAVE_STDARG_H
#include <86box/86box.h>
#include "cpu.h"
#include <86box/timer.h>
#include <86box/io.h>
#include <86box/device.h>
#include <86box/mem.h>
#include <86box/pit.h>
#include <86box/port_92.h>
#include <86box/chipset.h>

#define INDEX (dev->index - 0x10)

typedef struct
{
    uint8_t index, regs[6];
} et6000_t;

#ifdef ENABLE_ET6000_LOG
int et6000_do_log = ENABLE_ET6000_LOG;
static void
et6000_log(const char *fmt, ...)
{
    va_list ap;

    if (et6000_do_log)
    {
        va_start(ap, fmt);
        pclog_ex(fmt, ap);
        va_end(ap);
    }
}
#else
#define et6000_log(fmt, ...)
#endif

static void et6000_shadow_control(int base, int size, int can_read, int can_write)
{
    mem_set_mem_state_both(base, size, (can_read ? MEM_READ_INTERNAL : MEM_READ_EXTANY) | (can_write ? MEM_WRITE_INTERNAL : MEM_WRITE_EXTANY));
    flushmmucache_nopc();
}

static void
et6000_write(uint16_t addr, uint8_t val, void *priv)
{
    et6000_t *dev = (et6000_t *)priv;

    switch (addr)
    {
    case 0x22:
        dev->index = val;
        break;
    case 0x23:
        switch (INDEX)
        {
        case 0: /* System Configuration Register */
            dev->regs[INDEX] = val & 0xdf;
            et6000_shadow_control(0xa0000, 0x20000, val & 1, val & 1);
            refresh_at_enable = !(val & 0x10);
            break;

        case 1: /* CACHE Configuration and Non-Cacheable Block Size */
            dev->regs[INDEX] = val & 0xf0;
            break;

        case 2: /* Non-Cacheable Block Address Register */
            dev->regs[INDEX] = val & 0xfe;
            break;

        case 3: /* DRAM Bank and Type Configuration Register */
            dev->regs[INDEX] = val;
            break;

        case 4: /* DRAM Configuration Register */
            dev->regs[INDEX] = val;
            et6000_shadow_control(0xc0000, 0x10000, (dev->regs[0x15] & 2) && (val & 0x20), (dev->regs[0x15] & 2) && (val & 0x20) && (dev->regs[0x15] & 1));
            et6000_shadow_control(0xd0000, 0x10000, (dev->regs[0x15] & 8) && (val & 0x20), (dev->regs[0x15] & 8) && (val & 0x20) && (dev->regs[0x15] & 4));
            break;

        case 5: /* Shadow RAM Configuration Register */
            dev->regs[INDEX] = val;
            et6000_shadow_control(0xc0000, 0x10000, (val & 2) && (dev->regs[0x14] & 0x20), (val & 2) && (dev->regs[0x14] & 0x20) && (val & 1));
            et6000_shadow_control(0xd0000, 0x10000, (val & 8) && (dev->regs[0x14] & 0x20), (val & 8) && (dev->regs[0x14] & 0x20) && (val & 4));
            et6000_shadow_control(0xe0000, 0x10000, val & 0x20, (val & 0x20) && (val & 0x10));
            et6000_shadow_control(0xf0000, 0x10000, val & 0x40, !(val & 0x40));
            break;
        }
        et6000_log("ET6000: dev->regs[%02x] = %02x\n", dev->index, dev->regs[dev->index]);
        break;
    }
}

static uint8_t
et6000_read(uint16_t addr, void *priv)
{
    et6000_t *dev = (et6000_t *)priv;

    return ((addr == 0x23) && (INDEX >= 0) && (INDEX <= 5)) ? dev->regs[INDEX] : 0xff;
}

static void
et6000_close(void *priv)
{
    et6000_t *dev = (et6000_t *)priv;

    free(dev);
}

static void *
et6000_init(const device_t *info)
{
    et6000_t *dev = (et6000_t *)malloc(sizeof(et6000_t));
    memset(dev, 0, sizeof(et6000_t));

    /* Port 92h */
    device_add(&port_92_device);

    /* Defaults */
    dev->regs[3] = 1;

    /* Shadow Programming */
    et6000_shadow_control(0xf0000, 0x10000, 0, 1);

    io_sethandler(0x0022, 2, et6000_read, NULL, NULL, et6000_write, NULL, NULL, dev); /* Ports 22h-23h: ETEQ Cheetah ET6000 */

    return dev;
}

const device_t et6000_device = {
    "ETEQ Cheetah ET6000",
    "et6000",
    0,
    0,
    et6000_init,
    et6000_close,
    NULL,
    {NULL},
    NULL,
    NULL,
    NULL};
