// SPDX-License-Identifier: GPL-2.0-or-later
/*
 * (c) 1997-1998  Grant R. Guenther <grant@torque.net>
 *
 * on26.c is a low-level protocol driver for the
 * OnSpec 90c26 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 >> 4) & 0x0f) | (b & 0xf0))

#define P1						      \
	do {						      \
		w2(5); w2(0xd); w2(5); w2(0xd); w2(5); w2(4); \
	} while (0)

#define P2					\
	do {					\
		w2(5); w2(7); w2(5); w2(4);	\
	} while (0)

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

static int on26_read_regr(struct pi_adapter *pi, int cont, int regr)
{
	int a, b, r;

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

	switch (pi->mode) {
	case 0:
		w0(1); P1; w0(r); P2; w0(0); P1;
		w2(6); a = r1(); w2(4);
		w2(6); b = r1(); w2(4);
		w2(6); w2(4); w2(6); w2(4);
		return j44(a, b);
	case 1:
		w0(1); P1; w0(r); P2; w0(0); P1;
		w2(0x26); a = r0(); w2(4); w2(0x26); w2(4);
		return a;
	case 2:
	case 3:
	case 4:
		w3(1); w3(1); w2(5); w4(r); w2(4);
		w3(0); w3(0); w2(0x24); a = r4(); w2(4);
		w2(0x24); (void)r4(); w2(4);
		return a;
	}

	return -1;
}

static void on26_write_regr(struct pi_adapter *pi, int cont, int regr, int val)
{
	int r = (regr << 2) + 1 + cont;

	switch (pi->mode) {
	case 0:
	case 1:
		w0(1); P1; w0(r); P2; w0(0); P1;
		w0(val); P2; w0(val); P2;
		break;
	case 2:
	case 3:
	case 4:
		w3(1); w3(1); w2(5); w4(r); w2(4);
		w3(0); w3(0);
		w2(5); w4(val); w2(4);
		w2(5); w4(val); w2(4);
		break;
	}
}

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

static void on26_connect(struct pi_adapter *pi)
{
	int x;

	pi->saved_r0 = r0();
	pi->saved_r2 = r2();

	CCP(0x20);
	if (pi->mode)
		x = 9;
	else
		x = 8;

	w0(2); P1; w0(8); P2;
	w0(2); P1; w0(x); P2;
}

static void on26_disconnect(struct pi_adapter *pi)
{
	if (pi->mode >= 2) {
		w3(4); w3(4); w3(4); w3(4);
	} else {
		w0(4); P1; w0(4); P1;
	}
	CCP(0x30);
	w0(pi->saved_r0);
	w2(pi->saved_r2);
}

#define	RESET_WAIT  200

/* hard reset */
static int on26_test_port(struct pi_adapter *pi)
{
	int i, m, d, x = 0, y = 0;

	pi->saved_r0 = r0();
	pi->saved_r2 = r2();

	d = pi->delay;
	m = pi->mode;
	pi->delay = 5;
	pi->mode = 0;

	w2(0xc);

	CCP(0x30); CCP(0);

	w0(0xfe); w0(0xaa); w0(0x55); w0(0); w0(0xff);
	i = ((r1() & 0xf0) << 4); w0(0x87);
	i |= (r1() & 0xf0); w0(0x78);
	w0(0x20); w2(4); w2(5);
	i |= ((r1() & 0xf0) >> 4);
	w2(4); w0(0xff);

	if (i == 0xb5f) {
		w0(2); P1; w0(0);   P2;
		w0(3); P1; w0(0);   P2;
		w0(2); P1; w0(8);   P2; udelay(100);
		w0(2); P1; w0(0xa); P2; udelay(100);
		w0(2); P1; w0(8);   P2; udelay(1000);

		on26_write_regr(pi, 0, 6, 0xa0);

		for (i = 0; i < RESET_WAIT; i++) {
			on26_write_regr(pi, 0, 6, 0xa0);
			x = on26_read_regr(pi, 0, 7);
			on26_write_regr(pi, 0, 6, 0xb0);
			y = on26_read_regr(pi, 0, 7);
			if (!((x & 0x80) || (y & 0x80)))
				break;
			mdelay(100);
		}

		if (i == RESET_WAIT)
			dev_err(&pi->dev,
				"on26: Device reset failed (%x,%x)\n", x, y);

		w0(4); P1; w0(4); P1;
	}

	CCP(0x30);

	pi->delay = d;
	pi->mode = m;
	w0(pi->saved_r0);
	w2(pi->saved_r2);

	return 5;
}

static void on26_read_block(struct pi_adapter *pi, char *buf, int count)
{
	int k, a, b;

	switch (pi->mode) {
	case 0:
		w0(1); P1; w0(1); P2; w0(2); P1; w0(0x18); P2; w0(0); P1;
		udelay(10);
		for (k = 0; k < count; k++) {
			w2(6); a = r1();
			w2(4); b = r1();
			buf[k] = j44(a, b);
		}
		w0(2); P1; w0(8); P2;
		break;
	case 1:
		w0(1); P1; w0(1); P2; w0(2); P1; w0(0x19); P2; w0(0); P1;
		udelay(10);
		for (k = 0; k < count / 2; k++) {
			w2(0x26); buf[2 * k] = r0();
			w2(0x24); buf[2 * k + 1] = r0();
		}
		w0(2); P1; w0(9); P2;
		break;
	case 2:
		w3(1); w3(1); w2(5); w4(1); w2(4);
		w3(0); w3(0); w2(0x24);
		udelay(10);
		for (k = 0; k < count; k++)
			buf[k] = r4();
		w2(4);
		break;
	case 3:
		w3(1); w3(1); w2(5); w4(1); w2(4);
		w3(0); w3(0); w2(0x24);
		udelay(10);
		for (k = 0; k < count / 2; k++)
			((u16 *)buf)[k] = r4w();
		w2(4);
		break;
	case 4:
		w3(1); w3(1); w2(5); w4(1); w2(4);
		w3(0); w3(0); w2(0x24);
		udelay(10);
		for (k = 0; k < count / 4; k++)
			((u32 *)buf)[k] = r4l();
		w2(4);
		break;
	}
}

static void on26_write_block(struct pi_adapter *pi, char *buf, int count)
{
	int k;

	switch (pi->mode) {
	case 0:
	case 1:
		w0(1); P1; w0(1); P2;
		w0(2); P1; w0(0x18 + pi->mode); P2; w0(0); P1;
		udelay(10);
		for (k = 0; k < count / 2; k++) {
			w2(5); w0(buf[2 * k]);
			w2(7); w0(buf[2 * k + 1]);
		}
		w2(5); w2(4);
		w0(2); P1; w0(8 + pi->mode); P2;
		break;
	case 2:
		w3(1); w3(1); w2(5); w4(1); w2(4);
		w3(0); w3(0); w2(0xc5);
		udelay(10);
		for (k = 0; k < count; k++)
			w4(buf[k]);
		w2(0xc4);
		break;
	case 3:
		w3(1); w3(1); w2(5); w4(1); w2(4);
		w3(0); w3(0); w2(0xc5);
		udelay(10);
		for (k = 0; k < count / 2; k++)
			w4w(((u16 *)buf)[k]);
		w2(0xc4);
		break;
	case 4:
		w3(1); w3(1); w2(5); w4(1); w2(4);
		w3(0); w3(0); w2(0xc5);
		udelay(10);
		for (k = 0; k < count / 4; k++)
			w4l(((u32 *)buf)[k]);
		w2(0xc4);
		break;
	}
}

static void on26_log_adapter(struct pi_adapter *pi)
{
	char *mode_string[5] = { "4-bit", "8-bit", "EPP-8", "EPP-16", "EPP-32" };

	dev_info(&pi->dev,
		 "OnSpec 90c26 at 0x%x, mode %d (%s), delay %d\n",
		 pi->port, pi->mode, mode_string[pi->mode], pi->delay);
}

static struct pi_protocol on26 = {
	.owner		= THIS_MODULE,
	.name		= "on26",
	.max_mode	= 5,
	.epp_first	= 2,
	.default_delay	= 1,
	.max_units	= 1,
	.write_regr	= on26_write_regr,
	.read_regr	= on26_read_regr,
	.write_block	= on26_write_block,
	.read_block	= on26_read_block,
	.connect	= on26_connect,
	.disconnect	= on26_disconnect,
	.test_port	= on26_test_port,
	.log_adapter	= on26_log_adapter,
};

MODULE_LICENSE("GPL");
MODULE_AUTHOR("Grant R. Guenther <grant@torque.net>");
MODULE_DESCRIPTION("Onspec 90c26 parallel port IDE adapter protocol driver");
module_pata_parport_driver(on26);