/*      $NetBSD: zs.c,v 1.6 2021/09/11 20:28:03 andvar Exp $    */

/*-
 * Copyright (c) 1996, 2005 The NetBSD Foundation, Inc.
 * All rights reserved.
 *
 * This code is derived from software contributed to The NetBSD Foundation
 * by Gordon W. Ross.
 *
 * 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 NETBSD FOUNDATION, INC. 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 FOUNDATION 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.
 */

/*
 * Zilog Z8530 Dual UART driver (machine-dependent part)
 *
 * Runs two serial lines per chip using slave drivers.
 * Plain tty/async lines use the zs_async slave.
 */

#include <sys/cdefs.h>
__KERNEL_RCSID(0, "$NetBSD: zs.c,v 1.6 2021/09/11 20:28:03 andvar Exp $");

#include "opt_ddb.h"

#include <sys/param.h>
#include <sys/device.h>
#include <sys/tty.h>
#include <sys/systm.h>
#include <sys/intr.h>

#include <machine/z8530var.h>
#include <dev/ic/z8530reg.h>

#include "ioconf.h"

/* console status for consinit() */
static struct zs_chanstate zs_conscs_store;
struct zs_chanstate *zs_conscs = &zs_conscs_store;
void *zs_consaddr;

/*
 * Some warts needed by z8530tty.c -
 * The default parity REALLY needs to be the same as the PROM uses,
 * or you can not see messages done with printf during boot-up...
 */
int zs_def_cflag = (CREAD | CS8 | HUPCL);

int
zs_print(void *aux, const char *name)
{
        struct zsc_attach_args *args = aux;

        if (name != NULL)
                aprint_normal("%s: ", name);

        if (args->channel != -1)
                aprint_normal(" channel %d", args->channel);

        return UNCONF;
}

int
zshard(void *arg)
{
        struct zsc_softc *zsc;
        int rval;

        zsc = arg;
        rval = zsc_intr_hard(zsc);
        if (zsc->zsc_cs[0]->cs_softreq || zsc->zsc_cs[1]->cs_softreq)
                softint_schedule(zsc->zsc_si);

        return rval;
}

/*
 * Compute the current baud rate given a ZS channel.
 */
int
zs_get_speed(struct zs_chanstate *cs)
{
        int tconst;

        tconst = zs_read_reg(cs, 12);
        tconst |= zs_read_reg(cs, 13) << 8;
        return TCONST_TO_BPS(cs->cs_brg_clk, tconst);
}

/*
 * MD functions for setting the baud rate and control modes.
 */
int
zs_set_speed(struct zs_chanstate *cs, int bps)
{
        int tconst, real_bps;

        if (bps == 0)
                return 0;

#ifdef  DIAGNOSTIC
        if (cs->cs_brg_clk == 0)
                panic("zs_set_speed");
#endif

        tconst = BPS_TO_TCONST(cs->cs_brg_clk, bps);
        if (tconst < 0)
                return EINVAL;

        /* Convert back to make sure we can do it. */
        real_bps = TCONST_TO_BPS(cs->cs_brg_clk, tconst);

        /* XXX - Allow some tolerance here? */
        if (real_bps != bps)
                return EINVAL;

        cs->cs_preg[12] = tconst;
        cs->cs_preg[13] = tconst >> 8;

        /* Caller will stuff the pending registers. */
        return 0;
}

int
zs_set_modes(struct zs_chanstate *cs, int cflag)
{
        int s;

        /*
         * Output hardware flow control on the chip is horrendous:
         * if carrier detect drops, the receiver is disabled, and if
         * CTS drops, the transmitter is stopped IN MID CHARACTER!
         * Therefore, NEVER set the HFC bit, and instead use the
         * status interrupt to detect CTS changes.
         */
        s = splserial();
        cs->cs_rr0_pps = 0;
        if ((cflag & (CLOCAL | MDMBUF)) != 0) {
                cs->cs_rr0_dcd = 0;
                if ((cflag & MDMBUF) == 0)
                        cs->cs_rr0_pps = ZSRR0_DCD;
        } else
                cs->cs_rr0_dcd = ZSRR0_DCD;
        if ((cflag & CRTSCTS) != 0) {
                cs->cs_wr5_dtr = ZSWR5_DTR;
                cs->cs_wr5_rts = ZSWR5_RTS;
                cs->cs_rr0_cts = ZSRR0_CTS;
        } else if ((cflag & MDMBUF) != 0) {
                cs->cs_wr5_dtr = 0;
                cs->cs_wr5_rts = ZSWR5_DTR;
                cs->cs_rr0_cts = ZSRR0_DCD;
        } else {
                cs->cs_wr5_dtr = ZSWR5_DTR | ZSWR5_RTS;
                cs->cs_wr5_rts = 0;
                cs->cs_rr0_cts = 0;
        }
        splx(s);

        /* Caller will stuff the pending registers. */
        return 0;
}

/*
 * Read or write the chip with suitable delays.
 */
uint8_t
zs_read_reg(struct zs_chanstate *cs, uint8_t reg)
{
        uint8_t val;

        *cs->cs_reg_csr = reg;

        val = *cs->cs_reg_csr;

        return val;
}

void
zs_write_reg(struct zs_chanstate *cs, uint8_t reg, uint8_t val)
{

        *cs->cs_reg_csr = reg;

        *cs->cs_reg_csr = val;

}

uint8_t
zs_read_csr(struct zs_chanstate *cs)
{
        uint8_t val;

        val = *cs->cs_reg_csr;

        return val;
}

void
zs_write_csr(struct zs_chanstate *cs, uint8_t val)
{

        *cs->cs_reg_csr = val;

}

uint8_t
zs_read_data(struct zs_chanstate *cs)
{
        uint8_t val;

        val = *cs->cs_reg_data;

        return val;
}

void
zs_write_data(struct zs_chanstate *cs, uint8_t val)
{

        *cs->cs_reg_data = val;
}

void
zs_abort(struct zs_chanstate *cs)
{

#ifdef DDB
        Debugger();
#endif
}

/*
 * Polled input char.
 */
int
zs_getc(void *arg)
{
        struct zs_chanstate *cs = arg;
        int s, c;
        uint8_t rr0;

        s = splhigh();
        /* Wait for a character to arrive. */
        do {
                rr0 = *cs->cs_reg_csr;
                ZS_DELAY();
        } while ((rr0 & ZSRR0_RX_READY) == 0);

        c = *cs->cs_reg_data;
        ZS_DELAY();
        splx(s);

        /*
         * This could be used by the kd driver to read scan codes,
         * so don't translate '\r' ==> '\n' here...
         */
        return c;
}

/*
 * Polled output char.
 */
void
zs_putc(void *arg, int c)
{
        struct zs_chanstate *cs = arg;
        int s;
        uint8_t rr0;

        s = splhigh();
        /* Wait for transmitter to become ready. */
        do {
                rr0 = *cs->cs_reg_csr;
                ZS_DELAY();
        } while ((rr0 & ZSRR0_TX_READY) == 0);

        *cs->cs_reg_data = c;
        ZS_DELAY();
        splx(s);
}

int
zscngetc(dev_t dev)
{

        return zs_getc((void *)zs_conscs);
}

void
zscnputc(dev_t dev, int c)
{

        zs_putc((void *)zs_conscs, c);
}