root/drivers/ata/pata_parport/on26.c
// 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);