/* $NetBSD: ppbus_1284.c,v 1.14 2021/11/14 20:51:57 andvar Exp $ */

/*-
 * Copyright (c) 1997 Nicolas Souchu
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 *
 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 *
 * FreeBSD: src/sys/dev/ppbus/ppb_1284.c,v 1.11 2000/01/14 08:03:14 nsouch Exp
 *
 */

/* General purpose routines for the IEEE1284-1994 Standard */

#include <sys/cdefs.h>
__KERNEL_RCSID(0, "$NetBSD: ppbus_1284.c,v 1.14 2021/11/14 20:51:57 andvar Exp $");

#include "opt_ppbus_1284.h"

#include <sys/param.h>
#include <sys/malloc.h>
#include <sys/systm.h>

#include <dev/ppbus/ppbus_conf.h>
#include <dev/ppbus/ppbus_base.h>
#include <dev/ppbus/ppbus_1284.h>
#include <dev/ppbus/ppbus_io.h>
#include <dev/ppbus/ppbus_var.h>


/* Wait for the peripheral up to 40ms */
static int
do_1284_wait(struct ppbus_softc * bus, char mask, char status)
{
        return (ppbus_poll_bus(bus->sc_dev, 4, mask, status,
                PPBUS_NOINTR | PPBUS_POLL));
}

/* Wait for the host up to 1 second (peripheral side) */
static int
do_peripheral_wait(struct ppbus_softc * bus, char mask, char status)
{
        return (ppbus_poll_bus(bus->sc_dev, 100, mask, status,
                PPBUS_NOINTR | PPBUS_POLL));
}


/* Unconditionally reset the error field */
static int
ppbus_1284_reset_error(struct ppbus_softc * bus, int state)
{
        bus->sc_1284_error = PPBUS_NO_ERROR;
        bus->sc_1284_state = state;
        return 0;
}


/* Get IEEE1284 state */
int
ppbus_1284_get_state(device_t dev)
{
        struct ppbus_softc *sc = device_private(dev);

        return sc->sc_1284_state;
}


/* Set IEEE1284 state if no error occurred */
int
ppbus_1284_set_state(device_t dev, int state)
{
        struct ppbus_softc * bus = device_private(dev);

        /* call ppbus_1284_reset_error() if you absolutly want to change
         * the state from PPBUS_ERROR to another */
        if ((bus->sc_1284_state != PPBUS_ERROR) &&
                        (bus->sc_1284_error == PPBUS_NO_ERROR)) {
                bus->sc_1284_state = state;
                bus->sc_1284_error = PPBUS_NO_ERROR;
        }

        return 0;
}


/* Set the IEEE1284 error field */
static int
ppbus_1284_set_error(struct ppbus_softc * bus, int error, int event)
{
        /* do not accumulate errors */
        if ((bus->sc_1284_error == PPBUS_NO_ERROR) &&
                        (bus->sc_1284_state != PPBUS_ERROR)) {
                bus->sc_1284_error = error;
                bus->sc_1284_state = PPBUS_ERROR;
        }

#ifdef DEBUG_1284
        printf("%s<1284>: error=%d status=0x%x event=%d\n",
                device_xname(bus->sc_dev), error, ppbus_rstr(bus->sc_dev),
                event);

#endif

        return 0;
}


/* Converts mode+options into ext. value */
static int
ppbus_request_mode(int mode, int options)
{
        int request_mode = 0;

        if (options & PPBUS_EXTENSIBILITY_LINK) {
                request_mode = EXT_LINK_1284_NORMAL;

        }
        else {
                switch (mode) {
                case PPBUS_NIBBLE:
                        request_mode = (options & PPBUS_REQUEST_ID) ?
                                        NIBBLE_1284_REQUEST_ID :
                                        NIBBLE_1284_NORMAL;
                        break;
                case PPBUS_PS2:
                        request_mode = (options & PPBUS_REQUEST_ID) ?
                                        BYTE_1284_REQUEST_ID :
                                        BYTE_1284_NORMAL;
                        break;
                case PPBUS_ECP:
                        if (options & PPBUS_USE_RLE)
                                request_mode = (options & PPBUS_REQUEST_ID) ?
                                        ECP_1284_RLE_REQUEST_ID :
                                        ECP_1284_RLE;
                        else
                                request_mode = (options & PPBUS_REQUEST_ID) ?
                                        ECP_1284_REQUEST_ID :
                                        ECP_1284_NORMAL;
                        break;
                case PPBUS_EPP:
                        request_mode = EPP_1284_NORMAL;
                        break;
                default:
                        panic("%s: unsupported mode %d\n", __func__, mode);
                }
        }

        return (request_mode);
}


/* Negotiate the peripheral side */
int
ppbus_peripheral_negotiate(device_t dev, int mode, int options)
{
        struct ppbus_softc * bus = device_private(dev);
        int spin, request_mode, error = 0;
        char r;

        ppbus_1284_terminate(dev);
        ppbus_1284_set_state(dev, PPBUS_PERIPHERAL_NEGOTIATION);

        /* compute ext. value */
        request_mode = ppbus_request_mode(mode, options);

        /* wait host */
        spin = 10;
        while (spin-- && (ppbus_rstr(dev) & nBUSY))
                DELAY(1);

        /* check termination */
        if (!(ppbus_rstr(dev) & SELECT) || !spin) {
                error = ENODEV;
                goto error;
        }

        /* Event 4 - read ext. value */
        r = ppbus_rdtr(dev);

        /* nibble mode is not supported */
        if ((r == (char)request_mode) ||
                        (r == NIBBLE_1284_NORMAL)) {

                /* Event 5 - restore direction bit, no data avail */
                ppbus_wctr(dev, (STROBE | nINIT) & ~(SELECTIN));
                DELAY(1);

                /* Event 6 */
                ppbus_wctr(dev, (nINIT) & ~(SELECTIN | STROBE));

                if (r == NIBBLE_1284_NORMAL) {
#ifdef DEBUG_1284
                        printf("R");
#endif
                        ppbus_1284_set_error(bus, PPBUS_MODE_UNSUPPORTED, 4);
                        error = EINVAL;
                        goto error;
                }
                else {
                        ppbus_1284_set_state(dev, PPBUS_PERIPHERAL_IDLE);
#ifdef DEBUG_1284
                        printf("A");
#endif
                        /* negotiation succeeds */
                }
        }
        else {
                /* Event 5 - mode not supported */
                ppbus_wctr(dev, SELECTIN);
                DELAY(1);

                /* Event 6 */
                ppbus_wctr(dev, (SELECTIN) & ~(STROBE | nINIT));
                ppbus_1284_set_error(bus, PPBUS_MODE_UNSUPPORTED, 4);

#ifdef DEBUG_1284
                printf("r");
#endif
                error = EINVAL;
                goto error;
        }

        return (0);

error:
        ppbus_peripheral_terminate(dev, PPBUS_WAIT);
        return (error);
}


/* Terminate peripheral transfer side. Always return 0 in compatible mode */
int
ppbus_peripheral_terminate(device_t dev, int how)
{
        struct ppbus_softc * bus = device_private(dev);
        int error = 0;

#ifdef DEBUG_1284
        printf("t");
#endif

        ppbus_1284_set_state(dev, PPBUS_PERIPHERAL_TERMINATION);

        /* Event 22 - wait up to host response time (1s) */
        if ((error = do_peripheral_wait(bus, SELECT | nBUSY, 0))) {
                ppbus_1284_set_error(bus, PPBUS_TIMEOUT, 22);
                goto error;
        }

        /* Event 24 */
        ppbus_wctr(dev, (nINIT | STROBE) & ~(AUTOFEED | SELECTIN));

        /* Event 25 - wait up to host response time (1s) */
        if ((error = do_peripheral_wait(bus, nBUSY, nBUSY))) {
                ppbus_1284_set_error(bus, PPBUS_TIMEOUT, 25);
                goto error;
        }

        /* Event 26 */
        ppbus_wctr(dev, (SELECTIN | nINIT | STROBE) & ~(AUTOFEED));
        DELAY(1);
        /* Event 27 */
        ppbus_wctr(dev, (SELECTIN | nINIT) & ~(STROBE | AUTOFEED));

        /* Event 28 - wait up to host response time (1s) */
        if ((error = do_peripheral_wait(bus, nBUSY, 0))) {
                ppbus_1284_set_error(bus, PPBUS_TIMEOUT, 28);
                goto error;
        }

error:
        ppbus_1284_terminate(dev);
        ppbus_1284_set_state(dev, PPBUS_FORWARD_IDLE);

        return (0);
}


/* Write 1 byte to host in BYTE mode (peripheral side) */
static int
byte_peripheral_outbyte(device_t dev, char *buffer, int last)
{
        struct ppbus_softc * bus = device_private(dev);
        int error = 0;

        /* Event 7 */
        if ((error = do_1284_wait(bus, nBUSY, nBUSY))) {
                ppbus_1284_set_error(bus, PPBUS_TIMEOUT, 7);
                goto error;
        }

        /* check termination */
        if (!(ppbus_rstr(dev) & SELECT)) {
                ppbus_peripheral_terminate(dev, PPBUS_WAIT);
                goto error;
        }

        /* Event 15 - put byte on data lines */
#ifdef DEBUG_1284
        printf("B");
#endif
        ppbus_wdtr(dev, *buffer);

        /* Event 9 */
        ppbus_wctr(dev, (AUTOFEED | STROBE) & ~(nINIT | SELECTIN));

        /* Event 10 - wait data read */
        if ((error = do_peripheral_wait(bus, nBUSY, 0))) {
                ppbus_1284_set_error(bus, PPBUS_TIMEOUT, 16);
                goto error;
        }

        /* Event 11 */
        if (!last) {
                ppbus_wctr(dev, (AUTOFEED) & ~(nINIT | STROBE | SELECTIN));
        } else {
                ppbus_wctr(dev, (nINIT) & ~(STROBE | SELECTIN | AUTOFEED));
        }

#if 0
        /* Event 16 - wait strobe */
        if ((error = do_peripheral_wait(bus, nACK | nBUSY, 0))) {
                ppbus_1284_set_error(bus, PPBUS_TIMEOUT, 16);
                goto error;
        }
#endif

        /* check termination */
        if (!(ppbus_rstr(dev) & SELECT)) {
                ppbus_peripheral_terminate(dev, PPBUS_WAIT);
                goto error;
        }

error:
        return (error);
}


/* Write n bytes to host in BYTE mode (peripheral side) */
int
byte_peripheral_write(device_t dev, char *buffer, int len,
        int *sent)
{
        int error = 0, i;
        char r;

        ppbus_1284_set_state(dev, PPBUS_PERIPHERAL_TRANSFER);

        /* wait forever, the remote host is master and should initiate
         * termination
         */
        for(i = 0; i < len; i++) {
                /* force remote nFAULT low to release the remote waiting
                 * process, if any
                 */
                r = ppbus_rctr(dev);
                ppbus_wctr(dev, r & ~nINIT);

#ifdef DEBUG_1284
                printf("y");
#endif
                /* Event 7 */
                error = ppbus_poll_bus(dev, PPBUS_FOREVER, nBUSY, nBUSY,
                                        PPBUS_INTR);

                if (error && error != EWOULDBLOCK)
                        goto error;

#ifdef DEBUG_1284
                printf("b");
#endif
                if ((error = byte_peripheral_outbyte(dev, buffer+i, (i == len-1))))
                        goto error;
        }
error:
        if (!error)
                ppbus_1284_set_state(dev, PPBUS_PERIPHERAL_IDLE);

        *sent = i;
        return (error);
}


/* Read the device ID using the specified mode */
int
ppbus_1284_read_id(device_t dev, int mode, char ** buffer,
                size_t * size, size_t * read)
{
        u_int16_t msg_sz;
        u_int8_t length_field;
        u_int8_t old_mode;
        int error;
        int old_ivar;
        int new_ivar = 1;

        error = ppbus_read_ivar(dev, PPBUS_IVAR_IEEE, &old_ivar);
        if(error) {
                printf("%s(%s): error reading PPBUS_IVAR_IEEE.\n", __func__,
                        device_xname(dev));
                return error;
        }
        if(old_ivar == 0) {
                error = ppbus_write_ivar(dev, PPBUS_IVAR_IEEE, &new_ivar);
                if(error) {
                        printf("%s(%s): error enabling IEEE usage.\n", __func__,
                                device_xname(dev));
                        return error;
                }
        }

        old_mode = ppbus_get_mode(dev);
        switch (mode) {
        case PPBUS_NIBBLE:
        case PPBUS_ECP:
        case PPBUS_BYTE:
                error = ppbus_set_mode(dev, mode, PPBUS_REQUEST_ID);
                if(error) {
                        printf("%s(%s): error setting bus mode.\n", __func__,
                                device_xname(dev));
                        goto end_read_id;
                }
                break;
        default:
                printf("%s(%s): mode does not support returning device ID.\n",
                        __func__, device_xname(dev));
                error = ENODEV;
                goto end_read_id;
        }

        error = ppbus_read(dev, &length_field, 1, 0, read);
        if(error) {
                printf("%s(%s): error reading first byte.\n", __func__,
                        device_xname(dev));
                goto end_read_id;
        }
        msg_sz = length_field;
        error = ppbus_read(dev, &length_field, 1, 0, read);
        if(error) {
                printf("%s(%s): error reading second byte.\n",
                        __func__, device_xname(dev));
                goto end_read_id;
        }
        msg_sz <<= 8;
        msg_sz |= length_field;
        msg_sz -= 2;
        if(msg_sz <= 0) {
                printf("%s(%s): device ID length <= 0.\n", __func__,
                        device_xname(dev));
                goto end_read_id;
        }
        *buffer = malloc(msg_sz, M_DEVBUF, M_WAITOK);
        *size = msg_sz;
        error = ppbus_read(dev, *buffer, msg_sz, 0, read);

end_read_id:
        ppbus_set_mode(dev, old_mode, 0);
        if(old_ivar == 0) {
                if(ppbus_write_ivar(dev, PPBUS_IVAR_IEEE, &old_ivar)) {
                        printf("%s(%s): error restoring PPBUS_IVAR_IEEE.\n",
                                __func__, device_xname(dev));
                }
        }
        return (error);
}

/*
 * IEEE1284 negotiation phase: after negotiation, nFAULT is low if data is
 * available for reverse modes.
 */
int
ppbus_1284_negotiate(device_t dev, int mode, int options)
{
        struct ppbus_softc * bus = device_private(dev);
        int error;
        int request_mode;

#ifdef DEBUG_1284
        printf("n");
#endif

        if (ppbus_1284_get_state(dev) >= PPBUS_PERIPHERAL_NEGOTIATION)
                ppbus_peripheral_terminate(dev, PPBUS_WAIT);

#ifdef DEBUG_1284
        printf("%d", mode);
#endif

        /* ensure the host is in compatible mode */
        ppbus_1284_terminate(dev);

        /* reset error to catch the actual negotiation error */
        ppbus_1284_reset_error(bus, PPBUS_FORWARD_IDLE);

        /* calculate ext. value */
        request_mode = ppbus_request_mode(mode, options);

        /* default state */
        ppbus_wctr(dev, (nINIT | SELECTIN) & ~(STROBE | AUTOFEED));
        DELAY(1);

        /* enter negotiation phase */
        ppbus_1284_set_state(dev, PPBUS_NEGOTIATION);

        /* Event 0 - put the exten. value on the data lines */
        ppbus_wdtr(dev, request_mode);

#ifdef PERIPH_1284
        /* request remote host attention */
        ppbus_wctr(dev, (nINIT | STROBE) & ~(AUTOFEED | SELECTIN));
        DELAY(1);
        ppbus_wctr(dev, (nINIT) & ~(STROBE | AUTOFEED | SELECTIN));
#else
        DELAY(1);

#endif /* !PERIPH_1284 */

        /* Event 1 - enter IEEE1284 mode */
        ppbus_wctr(dev, (nINIT | AUTOFEED) & ~(STROBE | SELECTIN));

#ifdef PERIPH_1284
        /* ignore the PError line, wait a bit more, remote host's
         * interrupts don't respond fast enough */
        if (ppbus_poll_bus(bus, 40, nACK | SELECT | nFAULT,
                                SELECT | nFAULT, PPBUS_NOINTR | PPBUS_POLL)) {
                ppbus_1284_set_error(bus, PPBUS_NOT_IEEE1284, 2);
                error = ENODEV;
                goto error;
        }
#else
        /* Event 2 - trying IEEE1284 dialog */
        if (do_1284_wait(bus, nACK | PERROR | SELECT | nFAULT,
                        PERROR  | SELECT | nFAULT)) {
                ppbus_1284_set_error(bus, PPBUS_NOT_IEEE1284, 2);
                error = ENODEV;
                goto error;
        }
#endif /* !PERIPH_1284 */

        /* Event 3 - latch the ext. value to the peripheral */
        ppbus_wctr(dev, (nINIT | STROBE | AUTOFEED) & ~SELECTIN);
        DELAY(1);

        /* Event 4 - IEEE1284 device recognized */
        ppbus_wctr(dev, nINIT & ~(SELECTIN | AUTOFEED | STROBE));

        /* Event 6 - waiting for status lines */
        if (do_1284_wait(bus, nACK, nACK)) {
                ppbus_1284_set_error(bus, PPBUS_TIMEOUT, 6);
                error = EBUSY;
                goto error;
        }

        /* Event 7 - querying result consider nACK not to misunderstand
         * a remote computer terminate sequence */
        if (options & PPBUS_EXTENSIBILITY_LINK) {
                /* XXX not fully supported yet */
                ppbus_1284_terminate(dev);
                error = ENODEV;
                goto error;
                /* return (0); */
        }
        if (request_mode == NIBBLE_1284_NORMAL) {
                if (do_1284_wait(bus, nACK | SELECT, nACK)) {
                        ppbus_1284_set_error(bus, PPBUS_MODE_UNSUPPORTED, 7);
                        error = ENODEV;
                        goto error;
                }
        } else {
                if (do_1284_wait(bus, nACK | SELECT, SELECT | nACK)) {
                        ppbus_1284_set_error(bus, PPBUS_MODE_UNSUPPORTED, 7);
                        error = ENODEV;
                        goto error;
                }
        }

        switch (mode) {
        case PPBUS_NIBBLE:
        case PPBUS_PS2:
                /* enter reverse idle phase */
                ppbus_1284_set_state(dev, PPBUS_REVERSE_IDLE);
                break;
        case PPBUS_ECP:
                /* negotiation ok, now setup the communication */
                ppbus_1284_set_state(dev, PPBUS_SETUP);
                ppbus_wctr(dev, (nINIT | AUTOFEED) & ~(SELECTIN | STROBE));

#ifdef PERIPH_1284
                /* ignore PError line */
                if (do_1284_wait(bus, nACK | SELECT | nBUSY,
                                        nACK | SELECT | nBUSY)) {
                        ppbus_1284_set_error(bus, PPBUS_TIMEOUT, 30);
                        error = ENODEV;
                        goto error;
                }
#else
                if (do_1284_wait(bus, nACK | SELECT | PERROR | nBUSY,
                                        nACK | SELECT | PERROR | nBUSY)) {
                        ppbus_1284_set_error(bus, PPBUS_TIMEOUT, 30);
                        error = ENODEV;
                        goto error;
                }
#endif /* !PERIPH_1284 */

                /* ok, the host enters the ForwardIdle state */
                ppbus_1284_set_state(dev, PPBUS_ECP_FORWARD_IDLE);
                break;
        case PPBUS_EPP:
                ppbus_1284_set_state(dev, PPBUS_EPP_IDLE);
                break;
        default:
                panic("%s: unknown mode (%d)!", __func__, mode);
        }

        return 0;

error:
        ppbus_1284_terminate(dev);
        return error;
}

/*
 * IEEE1284 termination phase, return code should ignored since the host
 * is _always_ in compatible mode after ppbus_1284_terminate()
 */
int
ppbus_1284_terminate(device_t dev)
{
        struct ppbus_softc * bus = device_private(dev);

#ifdef DEBUG_1284
        printf("T");
#endif

        /* do not reset error here to keep the error that
         * may occurred before the ppbus_1284_terminate() call */
        ppbus_1284_set_state(dev, PPBUS_TERMINATION);

#ifdef PERIPH_1284
        /* request remote host attention */
        ppbus_wctr(dev, (nINIT | STROBE | SELECTIN) & ~(AUTOFEED));
        DELAY(1);
#endif /* PERIPH_1284 */

        /* Event 22 - set nSelectin low and nAutoFeed high */
        ppbus_wctr(dev, (nINIT | SELECTIN) & ~(STROBE | AUTOFEED));

        /* Event 24 - waiting for peripheral, Xflag ignored */
        if (do_1284_wait(bus, nACK | nBUSY | nFAULT, nFAULT)) {
                ppbus_1284_set_error(bus, PPBUS_TIMEOUT, 24);
                goto error;
        }

        /* Event 25 - set nAutoFd low */
        ppbus_wctr(dev, (nINIT | SELECTIN | AUTOFEED) & ~STROBE);

        /* Event 26 - compatible mode status is set */

        /* Event 27 - peripheral set nAck high */
        if (do_1284_wait(bus, nACK, nACK)) {
                ppbus_1284_set_error(bus, PPBUS_TIMEOUT, 27);
        }

        /* Event 28 - end termination, return to idle phase */
        ppbus_wctr(dev, (nINIT | SELECTIN) & ~(STROBE | AUTOFEED));

error:
        ppbus_1284_set_state(dev, PPBUS_FORWARD_IDLE);

        return (0);
}