// SPDX-License-Identifier: GPL-2.0-or-later
/*
 * (c) 1997-1998  Grant R. Guenther <grant@torque.net>
 *
 * dstr.c is a low-level protocol driver for the DataStor EP2000 parallel
 * to IDE adapter chip.
 */

#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"

/*
 * mode codes:  0  nybble reads, 8-bit writes
 *		1  8-bit reads and writes
 *		2  8-bit EPP mode
 *		3  EPP-16
 *		4  EPP-32
 */

#define j44(a, b)  (((a >> 3) & 0x07) | ((~a >> 4) & 0x08) | \
		    ((b << 1) & 0x70) | ((~b) & 0x80))

#define P1	w2(5);w2(0xd);w2(5);w2(4);
#define P2	w2(5);w2(7);w2(5);w2(4);
#define P3      w2(6);w2(4);w2(6);w2(4);

/*
 * cont = 0 - access the IDE register file
 * cont = 1 - access the IDE command set
 */
static int  cont_map[2] = { 0x20, 0x40 };

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

	r = regr + cont_map[cont];

	w0(0x81); P1;
	if (pi->mode)
		w0(0x11);
	else
		w0(1);
	P2; w0(r); P1;

	switch (pi->mode) {
	case 0:
		w2(6); a = r1(); w2(4); w2(6); b = r1(); w2(4);
		return j44(a, b);
	case 1:
		w0(0); w2(0x26); a = r0(); w2(4);
		return a;
	case 2:
	case 3:
	case 4:
		w2(0x24); a = r4(); w2(4);
		return a;
	}

	return -1;
}

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

	w0(0x81); P1;
	if (pi->mode >= 2)
		w0(0x11);
	else
		w0(1);
	P2; w0(r); P1;

	switch (pi->mode)  {
	case 0:
	case 1:
		w0(val); w2(5); w2(7); w2(5); w2(4);
		break;
	case 2:
	case 3:
	case 4:
		w4(val);
		break;
	}
}

#define  CCP(x)						\
	do {						\
		w0(0xff); w2(0xc); w2(4);		\
		w0(0xaa); w0(0x55); w0(0); w0(0xff);	\
		w0(0x87); w0(0x78);			\
		w0(x); w2(5); w2(4);			\
	} while (0)

static void dstr_connect(struct pi_adapter *pi)
{
	pi->saved_r0 = r0();
	pi->saved_r2 = r2();
	w2(4); CCP(0xe0); w0(0xff);
}

static void dstr_disconnect(struct pi_adapter *pi)
{
	CCP(0x30);
	w0(pi->saved_r0);
	w2(pi->saved_r2);
}

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

        w0(0x81); P1;
	if (pi->mode)
		w0(0x19);
	else
		w0(9);
	P2; w0(0x82); P1; P3; w0(0x20); P1;

	switch (pi->mode) {
	case 0:
		for (k = 0; k < count; k++) {
			w2(6); a = r1(); w2(4);
			w2(6); b = r1(); w2(4);
			buf[k] = j44(a, b);
		}
		break;
	case 1:
		w0(0);
		for (k = 0; k < count; k++) {
			w2(0x26);
			buf[k] = r0();
			w2(0x24);
		}
		w2(4);
		break;
	case 2:
		w2(0x24);
		for (k = 0; k < count; k++)
			buf[k] = r4();
		w2(4);
		break;
	case 3:
		w2(0x24);
		for (k = 0; k < count / 2; k++)
			((u16 *)buf)[k] = r4w();
		w2(4);
		break;
	case 4:
		w2(0x24);
		for (k = 0; k < count / 4; k++)
			((u32 *)buf)[k] = r4l();
		w2(4);
		break;
	}
}

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

	w0(0x81); P1;
	if (pi->mode)
		w0(0x19);
	else
		w0(9);
	P2; w0(0x82); P1; P3; w0(0x20); P1;

	switch (pi->mode) {
	case 0:
	case 1:
		for (k = 0; k < count; k++) {
			w2(5);
			w0(buf[k]);
			w2(7);
		}
		w2(5); w2(4);
		break;
	case 2:
		w2(0xc5);
		for (k = 0; k < count; k++)
			w4(buf[k]);
		w2(0xc4);
		break;
	case 3:
		w2(0xc5);
		for (k = 0; k < count / 2; k++)
			w4w(((u16 *)buf)[k]);
		w2(0xc4);
		break;
	case 4:
		w2(0xc5);
		for (k = 0; k < count / 4; k++)
			w4l(((u32 *)buf)[k]);
		w2(0xc4);
		break;
	}
}

static void dstr_log_adapter(struct pi_adapter *pi)

{
	char *mode_string[5] = { "4-bit", "8-bit", "EPP-8", "EPP-16", "EPP-32" };

	dev_info(&pi->dev,
		 "DataStor EP2000 at 0x%x, mode %d (%s), delay %d\n",
		 pi->port, pi->mode, mode_string[pi->mode], pi->delay);
}

static struct pi_protocol dstr = {
	.owner		= THIS_MODULE,
	.name		= "dstr",
	.max_mode	= 5,
	.epp_first	= 2,
	.default_delay	= 1,
	.max_units	= 1,
	.write_regr	= dstr_write_regr,
	.read_regr	= dstr_read_regr,
	.write_block	= dstr_write_block,
	.read_block	= dstr_read_block,
	.connect	= dstr_connect,
	.disconnect	= dstr_disconnect,
	.log_adapter	= dstr_log_adapter,
};

MODULE_LICENSE("GPL");
MODULE_AUTHOR("Grant R. Guenther <grant@torque.net>");
MODULE_DESCRIPTION("DataStor EP2000 parallel port IDE adapter protocol driver");
module_pata_parport_driver(dstr);