// SPDX-License-Identifier: GPL-2.0-or-later
/*
 * (c) 1997-8  Grant R. Guenther <grant@torque.net>
 *
 * aten.c is a low-level protocol driver for the ATEN EH-100
 * parallel port adapter.  The EH-100 supports 4-bit and 8-bit
 * modes only.  There is also an EH-132 which supports EPP mode
 * transfers.  The EH-132 is not yet supported.
 */

#include <linux/module.h>
#include <linux/init.h>
#include <linux/delay.h>
#include <linux/kernel.h>
#include <linux/wait.h>
#include <linux/types.h>
#include <asm/io.h>
#include "pata_parport.h"

#define j44(a,b)                ((((a>>4)&0x0f)|(b&0xf0))^0x88)

/*
 * cont = 0 - access the IDE register file
 * cont = 1 - access the IDE command set
 */
static int  cont_map[2] = { 0x08, 0x20 };

static void aten_write_regr(struct pi_adapter *pi, int cont, int regr, int val)
{
        int r = regr + cont_map[cont] + 0x80;

        w0(r); w2(0xe); w2(6); w0(val); w2(7); w2(6); w2(0xc);
}

static int aten_read_regr(struct pi_adapter *pi, int cont, int regr)
{
        int  a, b, r;

        r = regr + cont_map[cont] + 0x40;

        switch (pi->mode) {

        case 0:
                w0(r); w2(0xe); w2(6);
                w2(7); w2(6); w2(0);
                a = r1(); w0(0x10); b = r1(); w2(0xc);
                return j44(a,b);

        case 1:
                r |= 0x10;
                w0(r); w2(0xe); w2(6); w0(0xff);
                w2(0x27); w2(0x26); w2(0x20);
                a = r0();
                w2(0x26); w2(0xc);
                return a;
        }
        return -1;
}

static void aten_read_block(struct pi_adapter *pi, char *buf, int count)
{
        int  k, a, b, c, d;

        switch (pi->mode) {

        case 0:
                w0(0x48); w2(0xe); w2(6);
                for (k = 0; k < count / 2; k++) {
                        w2(7); w2(6); w2(2);
                        a = r1(); w0(0x58); b = r1();
                        w2(0); d = r1(); w0(0x48); c = r1();
                        buf[2 * k] = j44(c, d);
                        buf[2 * k + 1] = j44(a, b);
                }
                w2(0xc);
                break;

        case 1:
                w0(0x58); w2(0xe); w2(6);
                for (k = 0; k < count / 2; k++) {
                        w2(0x27); w2(0x26); w2(0x22);
                        a = r0(); w2(0x20); b = r0();
                        buf[2 * k] = b;
                        buf[2 * k + 1] = a;
                }
                w2(0x26); w2(0xc);
                break;
        }
}

static void aten_write_block(struct pi_adapter *pi, char *buf, int count)
{
        int k;

        w0(0x88); w2(0xe); w2(6);
        for (k = 0; k < count / 2; k++) {
                w0(buf[2 * k + 1]); w2(0xe); w2(6);
                w0(buf[2 * k]); w2(7); w2(6);
        }
        w2(0xc);
}

static void aten_connect(struct pi_adapter *pi)
{
        pi->saved_r0 = r0();
        pi->saved_r2 = r2();
        w2(0xc);
}

static void aten_disconnect(struct pi_adapter *pi)
{
        w0(pi->saved_r0);
        w2(pi->saved_r2);
}

static void aten_log_adapter(struct pi_adapter *pi)
{
        char *mode_string[2] = { "4-bit", "8-bit" };

        dev_info(&pi->dev,
                 "ATEN EH-100 at 0x%x, mode %d (%s), delay %d\n",
                 pi->port, pi->mode, mode_string[pi->mode], pi->delay);
}

static struct pi_protocol aten = {
        .owner          = THIS_MODULE,
        .name           = "aten",
        .max_mode       = 2,
        .epp_first      = 2,
        .default_delay  = 1,
        .max_units      = 1,
        .write_regr     = aten_write_regr,
        .read_regr      = aten_read_regr,
        .write_block    = aten_write_block,
        .read_block     = aten_read_block,
        .connect        = aten_connect,
        .disconnect     = aten_disconnect,
        .log_adapter    = aten_log_adapter,
};

MODULE_LICENSE("GPL");
MODULE_AUTHOR("Grant R. Guenther <grant@torque.net>");
MODULE_DESCRIPTION("ATEN EH-100 parallel port IDE adapter protocol driver");
module_pata_parport_driver(aten);