// SPDX-License-Identifier: GPL-2.0-or-later
/*
 * (c) 1996-1998  Grant R. Guenther <grant@torque.net>
 *
 * bpck.c is a low-level protocol driver for the MicroSolutions
 * "backpack" parallel port 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"

#undef r2
#undef w2
#undef PC

#define PC                      pi->private
#define r2()                    (PC=(in_p(2) & 0xff))
#define w2(byte)                {out_p(2,byte); PC = byte;}
#define t2(pat)                 {PC ^= pat; out_p(2,PC);}
#define e2()                    {PC &= 0xfe; out_p(2,PC);}
#define o2()                    {PC |= 1; out_p(2,PC);}

#define j44(l,h)     (((l>>3)&0x7)|((l>>4)&0x8)|((h<<1)&0x70)|(h&0x80))

/*
 * cont = 0 - access the IDE register file
 * cont = 1 - access the IDE command set
 * cont = 2 - use internal bpck register addressing
 */
static int  cont_map[3] = { 0x40, 0x48, 0 };

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

        r = regr + cont_map[cont];

        switch (pi->mode) {
        case 0:
                w0(r & 0xf); w0(r); t2(2); t2(4);
                l = r1();
                t2(4);
                h = r1();
                return j44(l, h);
        case 1:
                w0(r & 0xf); w0(r); t2(2);
                e2(); t2(0x20);
                t2(4); h = r0();
                t2(1); t2(0x20);
                return h;
        case 2:
        case 3:
        case 4:
                w0(r); w2(9); w2(0); w2(0x20);
                h = r4();
                w2(0);
                return h;

        }
        return -1;
}

static void bpck_write_regr(struct pi_adapter *pi, int cont, int regr, int val)
{
        int r;

        r = regr + cont_map[cont];

        switch (pi->mode) {
        case 0:
        case 1: w0(r);
                t2(2);
                w0(val);
                o2(); t2(4); t2(1);
                break;
        case 2:
        case 3:
        case 4: w0(r); w2(9); w2(0);
                w0(val); w2(1); w2(3); w2(0);
                break;

        }
}

/* These macros access the bpck registers in native addressing */

#define WR(r,v)         bpck_write_regr(pi,2,r,v)
#define RR(r)           (bpck_read_regr(pi,2,r))

static void bpck_write_block(struct pi_adapter *pi, char *buf, int count)
{
        int i;

        switch (pi->mode) {

        case 0:
                WR(4, 0x40);
                w0(0x40); t2(2); t2(1);
                for (i = 0; i < count; i++) {
                        w0(buf[i]);
                        t2(4);
                }
                WR(4, 0);
                break;

        case 1:
                WR(4, 0x50);
                w0(0x40); t2(2); t2(1);
                for (i = 0; i < count; i++) {
                        w0(buf[i]);
                        t2(4);
                }
                WR(4, 0x10);
                break;

        case 2:
                WR(4, 0x48);
                w0(0x40); w2(9); w2(0); w2(1);
                for (i = 0; i < count; i++)
                        w4(buf[i]);
                w2(0);
                WR(4, 8);
                break;

        case 3:
                WR(4, 0x48);
                w0(0x40); w2(9); w2(0); w2(1);
                for (i = 0; i < count / 2; i++)
                        w4w(((u16 *)buf)[i]);
                w2(0);
                WR(4, 8);
                break;

        case 4:
                WR(4, 0x48);
                w0(0x40); w2(9); w2(0); w2(1);
                for (i = 0; i < count / 4; i++)
                        w4l(((u32 *)buf)[i]);
                w2(0);
                WR(4, 8);
                break;
        }
}

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

        switch (pi->mode) {

        case 0:
                WR(4, 0x40);
                w0(0x40); t2(2);
                for (i = 0; i < count; i++) {
                        t2(4); l = r1();
                        t2(4); h = r1();
                        buf[i] = j44(l, h);
                }
                WR(4, 0);
                break;

        case 1:
                WR(4, 0x50);
                w0(0x40); t2(2); t2(0x20);
                for (i = 0; i < count; i++) {
                        t2(4);
                        buf[i] = r0();
                }
                t2(1); t2(0x20);
                WR(4, 0x10);
                break;

        case 2:
                WR(4, 0x48);
                w0(0x40); w2(9); w2(0); w2(0x20);
                for (i = 0; i < count; i++)
                        buf[i] = r4();
                w2(0);
                WR(4, 8);
                break;

        case 3:
                WR(4, 0x48);
                w0(0x40); w2(9); w2(0); w2(0x20);
                for (i = 0; i < count / 2; i++)
                        ((u16 *)buf)[i] = r4w();
                w2(0);
                WR(4, 8);
                break;

        case 4:
                WR(4, 0x48);
                w0(0x40); w2(9); w2(0); w2(0x20);
                for (i = 0; i < count / 4; i++)
                        ((u32 *)buf)[i] = r4l();
                w2(0);
                WR(4, 8);
                break;

        }
}

static int bpck_probe_unit(struct pi_adapter *pi)
{
        int o1, o0, f7, id;
        int t, s;

        id = pi->unit;
        s = 0;
        w2(4); w2(0xe); r2(); t2(2);
        o1 = r1()&0xf8;
        o0 = r0();
        w0(255-id); w2(4); w0(id);
        t2(8); t2(8); t2(8);
        t2(2); t = r1()&0xf8;
        f7 = ((id % 8) == 7);
        if ((f7) || (t != o1)) {
                t2(2);
                s = r1() & 0xf8;
        }
        if ((t == o1) && ((!f7) || (s == o1)))  {
                w2(0x4c); w0(o0);
                return 0;
        }
        t2(8); w0(0); t2(2); w2(0x4c); w0(o0);
        return 1;
}

static void bpck_connect(struct pi_adapter *pi)
{
        pi->saved_r0 = r0();
        w0(0xff-pi->unit); w2(4); w0(pi->unit);
        t2(8); t2(8); t2(8);
        t2(2); t2(2);

        switch (pi->mode) {
        case 0:
                t2(8); WR(4, 0);
                break;
        case 1:
                t2(8); WR(4, 0x10);
                break;
        case 2:
        case 3:
        case 4:
                w2(0); WR(4, 8);
                break;
        }

        WR(5,8);

        /*
         * Possibly wrong, purpose unknown (fiddle with ESS logic ???)
         * if (pi->devtype == PI_PCD) {
         */
        WR(0x46, 0x10);
        WR(0x4c, 0x38);
        WR(0x4d, 0x88);
        WR(0x46, 0xa0);
        WR(0x41, 0);
        WR(0x4e, 8);
        /* } */
}

static void bpck_disconnect(struct pi_adapter *pi)
{
        w0(0);
        if (pi->mode >= 2) {
                w2(9); w2(0);
        } else {
                t2(2);
        }
        w2(0x4c); w0(pi->saved_r0);
}

static void bpck_force_spp(struct pi_adapter *pi)
{
        /* This fakes the EPP protocol to turn off EPP ... */
        pi->saved_r0 = r0();
        w0(0xff-pi->unit); w2(4); w0(pi->unit);
        t2(8); t2(8); t2(8);
        t2(2); t2(2);

        w2(0);
        w0(4); w2(9); w2(0);
        w0(0); w2(1); w2(3); w2(0);
        w0(0); w2(9); w2(0);
        w2(0x4c); w0(pi->saved_r0);
}

#define TEST_LEN  16

static int bpck_test_proto(struct pi_adapter *pi)
{
        int i, e, l, h, om;
        char buf[TEST_LEN];

        bpck_force_spp(pi);

        switch (pi->mode) {

        case 0:
                bpck_connect(pi);
                WR(0x13, 0x7f);
                w0(0x13); t2(2);
                for (i = 0; i < TEST_LEN; i++) {
                        t2(4); l = r1();
                        t2(4); h = r1();
                        buf[i] = j44(l, h);
                }
                bpck_disconnect(pi);
                break;

        case 1:
                bpck_connect(pi);
                WR(0x13, 0x7f);
                w0(0x13); t2(2); t2(0x20);
                for (i = 0; i < TEST_LEN; i++) {
                        t2(4);
                        buf[i] = r0();
                }
                t2(1); t2(0x20);
                bpck_disconnect(pi);
                break;

        case 2:
        case 3:
        case 4:
                om = pi->mode;
                pi->mode = 0;
                bpck_connect(pi);
                WR(7, 3);
                WR(4, 8);
                bpck_disconnect(pi);

                pi->mode = om;
                bpck_connect(pi);
                w0(0x13); w2(9); w2(1); w0(0); w2(3); w2(0); w2(0xe0);

                switch (pi->mode) {
                case 2:
                        for (i = 0; i < TEST_LEN; i++)
                                buf[i] = r4();
                        break;
                case 3:
                        for (i = 0; i < TEST_LEN / 2; i++)
                                ((u16 *)buf)[i] = r4w();
                        break;
                case 4:
                        for (i = 0; i < TEST_LEN / 4; i++)
                                ((u32 *)buf)[i] = r4l();
                        break;
                }

                w2(0);
                WR(7, 0);
                bpck_disconnect(pi);
                break;

        }

        dev_dbg(&pi->dev, "bpck: 0x%x unit %d mode %d: ",
                pi->port, pi->unit, pi->mode);
        print_hex_dump_debug("bpck: ", DUMP_PREFIX_NONE, TEST_LEN, 1, buf,
                             TEST_LEN, false);

        e = 0;
        for (i = 0; i < TEST_LEN; i++) {
                if (buf[i] != i + 1)
                        e++;
        }

        return e;
}

static void bpck_read_eeprom(struct pi_adapter *pi, char *buf)
{
        int i, j, k, p, v, f, om, od;

        bpck_force_spp(pi);

        om = pi->mode;  od = pi->delay;
        pi->mode = 0; pi->delay = 6;

        bpck_connect(pi);

        WR(4, 0);
        for (i = 0; i < 64; i++) {
                WR(6, 8);
                WR(6, 0xc);
                p = 0x100;
                for (k = 0; k < 9; k++) {
                        f = (((i + 0x180) & p) != 0) * 2;
                        WR(6, f + 0xc);
                        WR(6, f + 0xd);
                        WR(6, f + 0xc);
                        p = (p >> 1);
                }
                for (j = 0; j < 2; j++) {
                        v = 0;
                        for (k = 0; k < 8; k++) {
                                WR(6, 0xc);
                                WR(6, 0xd);
                                WR(6, 0xc);
                                f = RR(0);
                                v = 2 * v + (f == 0x84);
                        }
                        buf[2 * i + 1 - j] = v;
                }
        }
        WR(6, 8);
        WR(6, 0);
        WR(5, 8);

        bpck_disconnect(pi);

        if (om >= 2) {
                bpck_connect(pi);
                WR(7, 3);
                WR(4, 8);
                bpck_disconnect(pi);
        }

        pi->mode = om; pi->delay = od;
}

static int bpck_test_port(struct pi_adapter *pi)
{
        int i, r, m;

        /* Check for 8-bit port */
        w2(0x2c); i = r0(); w0(255-i); r = r0(); w0(i);
        m = -1;
        if (r == i)
                m = 2;
        if (r == (255-i))
                m = 0;

        w2(0xc);
        i = r0();
        w0(255-i);
        r = r0();
        w0(i);
        if (r != (255-i))
                m = -1;

        if (m == 0) {
                w2(6);
                w2(0xc);
                r = r0();
                w0(0xaa);
                w0(r);
                w0(0xaa);
        }
        if (m == 2) {
                w2(0x26);
                w2(0xc);
        }

        if (m == -1)
                return 0;

        return 5;
}

static void bpck_log_adapter(struct pi_adapter *pi)
{
        char *mode_str[5] = { "4-bit", "8-bit", "EPP-8", "EPP-16", "EPP-32" };
        char scratch[128];

        bpck_read_eeprom(pi,scratch);
        print_hex_dump_bytes("bpck EEPROM: ", DUMP_PREFIX_NONE, scratch, 128);
        dev_info(&pi->dev,
                 "backpack %8.8s unit %d at 0x%x, mode %d (%s), delay %d\n",
                 &scratch[110], pi->unit, pi->port, pi->mode,
                 mode_str[pi->mode], pi->delay);
}

static struct pi_protocol bpck = {
        .owner          = THIS_MODULE,
        .name           = "bpck",
        .max_mode       = 5,
        .epp_first      = 2,
        .default_delay  = 4,
        .max_units      = 255,
        .write_regr     = bpck_write_regr,
        .read_regr      = bpck_read_regr,
        .write_block    = bpck_write_block,
        .read_block     = bpck_read_block,
        .connect        = bpck_connect,
        .disconnect     = bpck_disconnect,
        .test_port      = bpck_test_port,
        .probe_unit     = bpck_probe_unit,
        .test_proto     = bpck_test_proto,
        .log_adapter    = bpck_log_adapter,
};

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