// SPDX-License-Identifier: GPL-2.0-or-later
/*
 * (c) 1998  Grant R. Guenther <grant@torque.net>
 *
 * ktti.c is a low-level protocol driver for the KT Technology
 * parallel port adapter.  This adapter is used in the "PHd"
 * portable hard-drives.  As far as I can tell, this device
 * supports 4-bit mode _only_.
*/

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

/*
 * cont = 0 - access the IDE register file
 * cont = 1 - access the IDE command set
 */
static int cont_map[2] = { 0x10, 0x08 };

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

	w0(r); w2(0xb); w2(0xa); w2(3); w2(6);
	w0(val); w2(3); w0(0); w2(6); w2(0xb);
}

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

        r = regr + cont_map[cont];

	w0(r); w2(0xb); w2(0xa); w2(9); w2(0xc); w2(9);
	a = r1(); w2(0xc);  b = r1(); w2(9); w2(0xc); w2(9);
	return j44(a, b);
}

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

	for (k = 0; k < count / 2; k++) {
		w0(0x10); w2(0xb); w2(0xa); w2(9); w2(0xc); w2(9);
		a = r1(); w2(0xc); b = r1(); w2(9);
		buf[2*k] = j44(a, b);
		a = r1(); w2(0xc); b = r1(); w2(9);
		buf[2*k+1] = j44(a, b);
	}
}

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

	for (k = 0; k < count / 2; k++) {
		w0(0x10); w2(0xb); w2(0xa); w2(3); w2(6);
		w0(buf[2 * k]); w2(3);
		w0(buf[2 * k + 1]); w2(6);
		w2(0xb);
	}
}

static void ktti_connect(struct pi_adapter *pi)
{
	pi->saved_r0 = r0();
	pi->saved_r2 = r2();
	w2(0xb); w2(0xa); w0(0); w2(3); w2(6);
}

static void ktti_disconnect(struct pi_adapter *pi)
{
	w2(0xb); w2(0xa); w0(0xa0); w2(3); w2(4);
	w0(pi->saved_r0);
	w2(pi->saved_r2);
}

static void ktti_log_adapter(struct pi_adapter *pi)
{
	dev_info(&pi->dev, "KT adapter at 0x%x, delay %d\n",
		 pi->port, pi->delay);
}

static struct pi_protocol ktti = {
	.owner		= THIS_MODULE,
	.name		= "ktti",
	.max_mode	= 1,
	.epp_first	= 2,
	.default_delay	= 1,
	.max_units	= 1,
	.write_regr	= ktti_write_regr,
	.read_regr	= ktti_read_regr,
	.write_block	= ktti_write_block,
	.read_block	= ktti_read_block,
	.connect	= ktti_connect,
	.disconnect	= ktti_disconnect,
	.log_adapter	= ktti_log_adapter,
};

MODULE_LICENSE("GPL");
MODULE_AUTHOR("Grant R. Guenther <grant@torque.net>");
MODULE_DESCRIPTION("KT Technology parallel port IDE adapter protocol driver");
module_pata_parport_driver(ktti);