// SPDX-License-Identifier: GPL-2.0-or-later
/*
 * (c) 1996-1998  Grant R. Guenther <grant@torque.net>
 *
 * on20.c is a low-level protocol driver for the
 * Onspec 90c20 parallel to IDE adapter.
 */

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

#define op(f)                                   \
        do {                                    \
                w2(4); w0(f); w2(5); w2(0xd);   \
                w2(5); w2(0xd); w2(5); w2(4);   \
        } while (0)

#define vl(v)                                   \
        do {                                    \
                w2(4); w0(v); w2(5);            \
                w2(7); w2(5); w2(4);            \
        } while (0)

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

/*
 * cont = 0 - access the IDE register file
 * cont = 1 - access the IDE command set
 */

static int on20_read_regr(struct pi_adapter *pi, int cont, int regr)
{
        int h, l, r;

        r = (regr << 2) + 1 + cont;

        op(1); vl(r); op(0);

        switch (pi->mode) {
        case 0:
                w2(4); w2(6); l = r1();
                w2(4); w2(6); h = r1();
                w2(4); w2(6); w2(4); w2(6); w2(4);
                return j44(l, h);
        case 1:
                w2(4); w2(0x26); r = r0();
                w2(4); w2(0x26); w2(4);
                return r;
        }

        return -1;
}

static void on20_write_regr(struct pi_adapter *pi, int cont, int regr, int val)
{
        int r = (regr << 2) + 1 + cont;

        op(1); vl(r);
        op(0); vl(val);
        op(0); vl(val);
}

static void on20_connect(struct pi_adapter *pi)
{
        pi->saved_r0 = r0();
        pi->saved_r2 = r2();

        w2(4); w0(0); w2(0xc); w2(4); w2(6); w2(4); w2(6); w2(4);
        if (pi->mode) {
                op(2); vl(8); op(2); vl(9);
        } else {
                op(2); vl(0); op(2); vl(8);
        }
}

static void on20_disconnect(struct pi_adapter *pi)
{
        w2(4); w0(7); w2(4); w2(0xc); w2(4);
        w0(pi->saved_r0);
        w2(pi->saved_r2);
}

static void on20_read_block(struct pi_adapter *pi, char *buf, int count)
{
        int k, l, h;

        op(1); vl(1); op(0);

        for (k = 0; k < count; k++) {
                if (pi->mode) {
                        w2(4); w2(0x26); buf[k] = r0();
                } else {
                        w2(6); l = r1(); w2(4);
                        w2(6); h = r1(); w2(4);
                        buf[k] = j44(l, h);
                }
        }
        w2(4);
}

static void on20_write_block(struct pi_adapter *pi, char *buf, int count)
{
        int k;

        op(1); vl(1); op(0);

        for (k = 0; k < count; k++) {
                w2(5); w0(buf[k]); w2(7);
        }
        w2(4);
}

static void on20_log_adapter(struct pi_adapter *pi)
{
        char *mode_string[2] = { "4-bit", "8-bit" };

        dev_info(&pi->dev,
                 "OnSpec 90c20 at 0x%x, mode %d (%s), delay %d\n",
                 pi->port, pi->mode, mode_string[pi->mode], pi->delay);
}

static struct pi_protocol on20 = {
        .owner          = THIS_MODULE,
        .name           = "on20",
        .max_mode       = 2,
        .epp_first      = 2,
        .default_delay  = 1,
        .max_units      = 1,
        .write_regr     = on20_write_regr,
        .read_regr      = on20_read_regr,
        .write_block    = on20_write_block,
        .read_block     = on20_read_block,
        .connect        = on20_connect,
        .disconnect     = on20_disconnect,
        .log_adapter    = on20_log_adapter,
};

MODULE_LICENSE("GPL");
MODULE_AUTHOR("Grant R. Guenther <grant@torque.net>");
MODULE_DESCRIPTION("Onspec 90c20 parallel port IDE adapter protocol driver");
module_pata_parport_driver(on20);