/*      $NetBSD: zs.c,v 1.63 2023/09/23 12:48:23 andvar Exp $   */

/*
* Copyright (c) 1996-1998 Bill Studenmund
* Copyright (c) 1995 Gordon W. Ross
* 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 ``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 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.
* Sun keyboard/mouse uses the zs_kbd/zs_ms slaves.
* Other ports use their own mice & keyboard slaves.
*
* Credits & history:
*
* With NetBSD 1.1, port-mac68k started using a port of the port-sparc
* (port-sun3?) zs.c driver (which was in turn based on code in the
* Berkeley 4.4 Lite release). Bill Studenmund did the port, with
* help from Allen Briggs and Gordon Ross <[email protected]>. Noud de
* Brouwer field-tested the driver at a local ISP.
*
* Bill Studenmund and Gordon Ross then ported the machine-independent
* z8530 driver to work with port-mac68k. NetBSD 1.2 contained an
* intermediate version (mac68k using a local, patched version of
* the m.i. drivers), with NetBSD 1.3 containing a full version.
*/

#include <sys/cdefs.h>
__KERNEL_RCSID(0, "$NetBSD: zs.c,v 1.63 2023/09/23 12:48:23 andvar Exp $");

#include "opt_ddb.h"
#include "opt_mac68k.h"

#include <sys/param.h>
#include <sys/systm.h>
#include <sys/proc.h>
#include <sys/device.h>
#include <sys/conf.h>
#include <sys/file.h>
#include <sys/ioctl.h>
#include <sys/tty.h>
#include <sys/time.h>
#include <sys/kernel.h>
#include <sys/syslog.h>
#include <sys/cpu.h>
#include <sys/intr.h>

#include <machine/autoconf.h>
#include <machine/psc.h>
#include <machine/viareg.h>

#include <dev/cons.h>
#include <dev/ic/z8530reg.h>
#include <machine/z8530var.h>
#include <mac68k/dev/zs_cons.h>

/* Are these in a header file anywhere? */
/* Booter flags interface */
#define ZSMAC_RAW       0x01
#define ZSMAC_LOCALTALK 0x02

#define PCLK    (9600 * 384)

/*
* Some warts needed by z8530tty.c -
*/
int zs_def_cflag = (CREAD | CS8 | HUPCL);

/*
* abort detection on console will now timeout after iterating on a loop
* the following # of times. Cheep hack. Also, abort detection is turned
* off after a timeout (i.e. maybe there's not a terminal hooked up).
*/
#define ZSABORT_DELAY 3000000

/*
* Define interrupt levels.
*/
#define ZSHARD_PRI      4       /* Wired on the CPU board... */
/*
* Serial port cards with zs chips on them are actually at the
* NuBus interrupt level, which is lower than 4. But blocking
* level 4 interrupts will block those interrupts too, so level
* 4 is fine.
*/

/* The layout of this is hardware-dependent (padding, order). */
struct zschan {
       volatile uint8_t zc_csr;        /* ctrl,status, and indirect access */
       uint8_t         zc_xxx0;
       uint8_t         zc_xxx1;        /* part of the other channel lives here! */
       uint8_t         zc_xxx2;        /* Yea Apple! */
       volatile uint8_t zc_data;       /* data */
       uint8_t         zc_xxx3;
       uint8_t         zc_xxx4;
       uint8_t         zc_xxx5;
};

/* Flags from cninit() */
static int zs_hwflags[2];
/* Default speed for each channel */
static int zs_defspeed[2] = {
       9600,           /* tty00 */
       9600,           /* tty01 */
};
/* console stuff */
void    *zs_conschan;
int     zs_consunit;
#ifdef  ZS_CONSOLE_ABORT
int     zs_cons_canabort = 1;
#else
int     zs_cons_canabort = 0;
#endif /* ZS_CONSOLE_ABORT*/
/* device to which the console is attached--if serial. */
dev_t   mac68k_zsdev;
/* Mac stuff */
extern volatile unsigned char *sccA;

int     zs_cn_check_speed(int);

/*
* Even though zsparam will set up the clock multiples, etc., we
* still set them here as: 1) mice & keyboards don't use zsparam,
* and 2) the console stuff uses these defaults before device
* attach.
*/

static uint8_t zs_init_reg[16] = {
       0,      /* 0: CMD (reset, etc.) */
       0,      /* 1: No interrupts yet. */
       0x18 + ZSHARD_PRI,      /* IVECT */
       ZSWR3_RX_8 | ZSWR3_RX_ENABLE,
       ZSWR4_CLK_X16 | ZSWR4_ONESB | ZSWR4_EVENP,
       ZSWR5_TX_8 | ZSWR5_TX_ENABLE,
       0,      /* 6: TXSYNC/SYNCLO */
       0,      /* 7: RXSYNC/SYNCHI */
       0,      /* 8: alias for data port */
       ZSWR9_MASTER_IE,
       0,      /*10: Misc. TX/RX control bits */
       ZSWR11_TXCLK_BAUD | ZSWR11_RXCLK_BAUD,
       ((PCLK/32)/9600)-2,     /*12: BAUDLO (default=9600) */
       0,                      /*13: BAUDHI (default=9600) */
       ZSWR14_BAUD_ENA,
       ZSWR15_BREAK_IE,
};

struct zschan *
zs_get_chan_addr(int channel)
{
       char *addr;
       struct zschan *zc;

       addr = (char *)__UNVOLATILE(sccA);
       if (channel == 0) {
               zc = (struct zschan *)(addr + 2);
               /* handle the fact the ports are intertwined. */
       } else {
               zc = (struct zschan *)(addr);
       }
       return (zc);
}


/* Find PROM mappings (for console support). */
int zsinited = 0; /* 0 = not, 1 = inited, not attached, 2= attached */

void
zs_init(void)
{
       zsinited = 1;
       if (zs_conschan != 0){ /* we might have moved io under the console */
               zs_conschan = zs_get_chan_addr(zs_consunit);
               /* so recalc the console port */
       }
}


/****************************************************************
* Autoconfig
****************************************************************/

/* Definition of the driver for autoconfig. */
static int      zsc_match(device_t, cfdata_t, void *);
static void     zsc_attach(device_t, device_t, void *);
static int      zsc_print(void *, const char *);

CFATTACH_DECL_NEW(zsc, sizeof(struct zsc_softc),
   zsc_match, zsc_attach, NULL, NULL);

extern struct cfdriver zsc_cd;

int zshard(void *);

/*
* Is the zs chip present?
*/
static int
zsc_match(device_t parent, cfdata_t cf, void *aux)
{
       if (zsinited == 2)
               return 0;

       return 1;
}

/*
* Attach a found zs.
*
* Match slave number to zs unit number, so that misconfiguration will
* not set up the keyboard as ttya, etc.
*/
static void
zsc_attach(device_t parent, device_t self, void *aux)
{
       struct zsc_softc *zsc = device_private(self);
       struct zsc_attach_args zsc_args;
       volatile struct zschan *zc;
       struct xzs_chanstate *xcs;
       struct zs_chanstate *cs;
       int s, chip, theflags, channel;

       zsc->zsc_dev = self;
       if (!zsinited)
               zs_init();
       zsinited = 2;

       chip = 0; /* We'll deal with chip types post 1.2 */
       aprint_normal(" chip type %d \n",chip);

       /*
        * Initialize software state for each channel.
        */
       for (channel = 0; channel < 2; channel++) {
               zsc_args.channel = channel;
               zsc_args.hwflags = zs_hwflags[channel];
               xcs = &zsc->xzsc_xcs_store[channel];
               cs  = &xcs->xzs_cs;
               zsc->zsc_cs[channel] = cs;

               zs_lock_init(cs);
               cs->cs_channel = channel;
               cs->cs_private = NULL;
               cs->cs_ops = &zsops_null;

               zc = zs_get_chan_addr(channel);
               cs->cs_reg_csr  = &zc->zc_csr;
               cs->cs_reg_data = &zc->zc_data;

               memcpy(cs->cs_creg, zs_init_reg, 16);
               memcpy(cs->cs_preg, zs_init_reg, 16);

               /* Current BAUD rate generator clock. */
               cs->cs_brg_clk = PCLK / 16;     /* RTxC is 230400*16, so use 230400 */
               cs->cs_defspeed = zs_defspeed[channel];
               cs->cs_defcflag = zs_def_cflag;

               /* Make these correspond to cs_defcflag (-crtscts) */
               cs->cs_rr0_dcd = ZSRR0_DCD;
               cs->cs_rr0_cts = 0;
               cs->cs_wr5_dtr = ZSWR5_DTR;
               cs->cs_wr5_rts = 0;

#ifdef __notyet__
               cs->cs_slave_type = ZS_SLAVE_NONE;
#endif

               /* Define BAUD rate stuff. */
               xcs->cs_clocks[0].clk = PCLK;
               xcs->cs_clocks[0].flags = ZSC_RTXBRG | ZSC_RTXDIV;
               xcs->cs_clocks[1].flags =
                       ZSC_RTXBRG | ZSC_RTXDIV | ZSC_VARIABLE | ZSC_EXTERN;
               xcs->cs_clocks[2].flags = ZSC_TRXDIV | ZSC_VARIABLE;
               xcs->cs_clock_count = 3;
               if (channel == 0) {
                       theflags = mac68k_machine.modem_flags;
                       xcs->cs_clocks[1].clk = mac68k_machine.modem_dcd_clk;
                       xcs->cs_clocks[2].clk = mac68k_machine.modem_cts_clk;
               } else {
                       theflags = mac68k_machine.print_flags;
                       xcs->cs_clocks[1].flags = ZSC_VARIABLE;
                       /*
                        * Yes, we aren't defining ANY clock source enables for the
                        * printer's DCD clock in. The hardware won't let us
                        * use it. But a clock will freak out the chip, so we
                        * let you set it, telling us to bar interrupts on the line.
                        */
                       xcs->cs_clocks[1].clk = mac68k_machine.print_dcd_clk;
                       xcs->cs_clocks[2].clk = mac68k_machine.print_cts_clk;
               }
               if (xcs->cs_clocks[1].clk)
                       zsc_args.hwflags |= ZS_HWFLAG_NO_DCD;
               if (xcs->cs_clocks[2].clk)
                       zsc_args.hwflags |= ZS_HWFLAG_NO_CTS;

               printf("zsc%d channel %d: d_speed %6d DCD clk %ld CTS clk %ld",
                               device_unit(self), channel, cs->cs_defspeed,
                               xcs->cs_clocks[1].clk, xcs->cs_clocks[2].clk);

               /* Set defaults in our "extended" chanstate. */
               xcs->cs_csource = 0;
               xcs->cs_psource = 0;
               xcs->cs_cclk_flag = 0;  /* Nothing fancy by default */
               xcs->cs_pclk_flag = 0;

               if (theflags & ZSMAC_RAW) {
                       zsc_args.hwflags |= ZS_HWFLAG_RAW;
                       printf(" (raw defaults)");
               }

               /*
                * XXX - This might be better done with a "stub" driver
                * (to replace zstty) that ignores LocalTalk for now.
                */
               if (theflags & ZSMAC_LOCALTALK) {
                       printf(" shielding from LocalTalk");
                       cs->cs_defspeed = 1;
                       cs->cs_creg[ZSRR_BAUDLO] = cs->cs_preg[ZSRR_BAUDLO] = 0xff;
                       cs->cs_creg[ZSRR_BAUDHI] = cs->cs_preg[ZSRR_BAUDHI] = 0xff;
                       zs_write_reg(cs, ZSRR_BAUDLO, 0xff);
                       zs_write_reg(cs, ZSRR_BAUDHI, 0xff);
                       /*
                        * If we might have LocalTalk, then make sure we have the
                        * Baud rate low-enough to not do any damage.
                        */
               }

               /*
                * We used to disable chip interrupts here, but we now
                * do that in zscnprobe, just in case MacOS left the chip on.
                */

               xcs->cs_chip = chip;

               /* Stash away a copy of the final H/W flags. */
               xcs->cs_hwflags = zsc_args.hwflags;

               printf("\n");

               /*
                * Look for a child driver for this channel.
                * The child attach will setup the hardware.
                */
               if (!config_found(self, (void *)&zsc_args, zsc_print,
                   CFARGS_NONE)) {
                       /* No sub-driver.  Just reset it. */
                       uint8_t reset = (channel == 0) ?
                               ZSWR9_A_RESET : ZSWR9_B_RESET;
                       s = splzs();
                       zs_write_reg(cs,  9, reset);
                       splx(s);
               }
       }

       if (current_mac_model->class == MACH_CLASSAV) {
               add_psc_lev4_intr(PSCINTR_SCCA, zshard, zsc);
               add_psc_lev4_intr(PSCINTR_SCCB, zshard, zsc);
       } else {
               intr_establish(zshard, zsc, ZSHARD_PRI);
       }
       zsc->zsc_softintr_cookie = softint_establish(SOFTINT_SERIAL,
           (void (*)(void *))zsc_intr_soft, zsc);

       /* Now safe to enable interrupts. */

       /*
        * Set the master interrupt enable and interrupt vector.
        * (common to both channels, do it on A)
        */
       cs = zsc->zsc_cs[0];
       s = splzs();
       /* interrupt vector */
       zs_write_reg(cs, 2, zs_init_reg[2]);
       /* master interrupt control (enable) */
       zs_write_reg(cs, 9, zs_init_reg[9]);
       splx(s);
}

static int
zsc_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
zsmdioctl(struct zs_chanstate *cs, u_long cmd, void *data)
{
       switch (cmd) {
       default:
               return (EPASSTHROUGH);
       }
       return (0);
}

void
zsmd_setclock(struct zs_chanstate *cs)
{
       struct xzs_chanstate *xcs = (void *)cs;

       if (cs->cs_channel != 0)
               return;

       /*
        * If the new clock has the external bit set, then select the
        * external source.
        */
       via_set_modem((xcs->cs_pclk_flag & ZSC_EXTERN) ? 1 : 0);
}

/*
* Do the minimum work to pull data off of the chip and queue it up
* for later processing.
*/
int
zshard(void *arg)
{
       struct zsc_softc *zsc = arg;
       int rval;

       if (zsc == NULL)
               return 0;

       rval = zsc_intr_hard(zsc);
       if ((zsc->zsc_cs[0]->cs_softreq) || (zsc->zsc_cs[1]->cs_softreq)) {
               softint_schedule(zsc->zsc_softintr_cookie);
       }
       return (rval);
}

#ifndef ZS_TOLERANCE
#define ZS_TOLERANCE 51
/* 5% in tenths of a %, plus 1 so that exactly 5% will be ok. */
#endif

/*
* check out a rate for acceptability from the internal clock
* source. Used in console config to validate a requested
* default speed. Placed here so that all the speed checking code is
* in one place.
*
* != 0 means ok.
*/
int
zs_cn_check_speed(int bps)
{
       int tc, rate;

       tc = BPS_TO_TCONST(PCLK / 16, bps);
       if (tc < 0)
               return 0;
       rate = TCONST_TO_BPS(PCLK / 16, tc);
       if (ZS_TOLERANCE > abs(((rate - bps)*1000)/bps))
               return 1;
       else
               return 0;
}

/*
* Search through the signal sources in the channel, and
* pick the best one for the baud rate requested. Return
* a -1 if not achievable in tolerance. Otherwise return 0
* and fill in the values.
*
* This routine draws inspiration from the Atari port's zs.c
* driver in NetBSD 1.1 which did the same type of source switching.
* Tolerance code inspired by comspeed routine in isa/com.c.
*
* By Bill Studenmund, 1996-05-12
*/
int
zs_set_speed(struct zs_chanstate *cs, int bps)
{
       struct xzs_chanstate *xcs = (void *) cs;
       int i, tc, tc0 = 0, tc1, s, sf = 0;
       int src, rate0, rate1, err, tol;

       if (bps == 0)
               return (0);

       src = -1;               /* no valid source yet */
       tol = ZS_TOLERANCE;

       /*
        * Step through all the sources and see which one matches
        * the best. A source has to match BETTER than tol to be chosen.
        * Thus if two sources give the same error, the first one will be
        * chosen. Also, allow for the possibility that one source might run
        * both the BRG and the direct divider (i.e. RTxC).
        */
       for (i=0; i < xcs->cs_clock_count; i++) {
               if (xcs->cs_clocks[i].clk <= 0)
                       continue;       /* skip non-existent or bad clocks */
               if (xcs->cs_clocks[i].flags & ZSC_BRG) {
                       /* check out BRG at /16 */
                       tc1 = BPS_TO_TCONST(xcs->cs_clocks[i].clk >> 4, bps);
                       if (tc1 >= 0) {
                               rate1 = TCONST_TO_BPS(xcs->cs_clocks[i].clk >> 4, tc1);
                               err = abs(((rate1 - bps)*1000)/bps);
                               if (err < tol) {
                                       tol = err;
                                       src = i;
                                       sf = xcs->cs_clocks[i].flags & ~ZSC_DIV;
                                       tc0 = tc1;
                                       rate0 = rate1;
                               }
                       }
               }
               if (xcs->cs_clocks[i].flags & ZSC_DIV) {
                       /*
                        * Check out either /1, /16, /32, or /64
                        * Note: for /1, you'd better be using a synchronized
                        * clock!
                        */
                       int b0 = xcs->cs_clocks[i].clk, e0 = abs(b0-bps);
                       int b1 = b0 >> 4, e1 = abs(b1-bps);
                       int b2 = b1 >> 1, e2 = abs(b2-bps);
                       int b3 = b2 >> 1, e3 = abs(b3-bps);

                       if (e0 < e1 && e0 < e2 && e0 < e3) {
                               err = e0;
                               rate1 = b0;
                               tc1 = ZSWR4_CLK_X1;
                       } else if (e0 > e1 && e1 < e2  && e1 < e3) {
                               err = e1;
                               rate1 = b1;
                               tc1 = ZSWR4_CLK_X16;
                       } else if (e0 > e2 && e1 > e2 && e2 < e3) {
                               err = e2;
                               rate1 = b2;
                               tc1 = ZSWR4_CLK_X32;
                       } else {
                               err = e3;
                               rate1 = b3;
                               tc1 = ZSWR4_CLK_X64;
                       }

                       err = (err * 1000)/bps;
                       if (err < tol) {
                               tol = err;
                               src = i;
                               sf = xcs->cs_clocks[i].flags & ~ZSC_BRG;
                               tc0 = tc1;
                               rate0 = rate1;
                       }
               }
       }
#ifdef ZSMACDEBUG
       printf("Checking for rate %d. Found source #%d.\n", bps, src);
#endif
       if (src == -1)
               return (EINVAL); /* no can do */

       /*
        * The M.I. layer likes to keep cs_brg_clk current, even though
        * we are the only ones who should be touching the BRG's rate.
        *
        * Note: we are assuming that any ZSC_EXTERN signal source comes in
        * on the RTxC pin. Correct for the mac68k obio zsc.
        */
       if (sf & ZSC_EXTERN)
               cs->cs_brg_clk = xcs->cs_clocks[i].clk >> 4;
       else
               cs->cs_brg_clk = PCLK / 16;

       /*
        * Now we have a source, so set it up.
        */
       s = splzs();
       xcs->cs_psource = src;
       xcs->cs_pclk_flag = sf;
       bps = rate0;
       if (sf & ZSC_BRG) {
               cs->cs_preg[4] = ZSWR4_CLK_X16;
               cs->cs_preg[11]= ZSWR11_RXCLK_BAUD | ZSWR11_TXCLK_BAUD;
               if (sf & ZSC_PCLK) {
                       cs->cs_preg[14] = ZSWR14_BAUD_ENA | ZSWR14_BAUD_FROM_PCLK;
               } else {
                       cs->cs_preg[14] = ZSWR14_BAUD_ENA;
               }
               tc = tc0;
       } else {
               cs->cs_preg[4] = tc0;
               if (sf & ZSC_RTXDIV) {
                       cs->cs_preg[11] = ZSWR11_RXCLK_RTXC | ZSWR11_TXCLK_RTXC;
               } else {
                       cs->cs_preg[11] = ZSWR11_RXCLK_TRXC | ZSWR11_TXCLK_TRXC;
               }
               cs->cs_preg[14]= 0;
               tc = 0xffff;
       }
       /* Set the BAUD rate divisor. */
       cs->cs_preg[12] = tc;
       cs->cs_preg[13] = tc >> 8;
       splx(s);

#ifdef ZSMACDEBUG
       printf("Rate is %7d, tc is %7d, source no. %2d, flags %4x\n",
           bps, tc, src, sf);
       printf("Registers are: 4 %x, 11 %x, 14 %x\n\n",
           cs->cs_preg[4], cs->cs_preg[11], cs->cs_preg[14]);
#endif

       cs->cs_preg[5] |= ZSWR5_RTS;    /* Make sure the drivers are on! */

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

int
zs_set_modes(struct zs_chanstate *cs, int cflag)
{
       struct xzs_chanstate *xcs = (void*)cs;
       int s;

       /*
        * Make sure we don't enable hfc on a signal line we're ignoring.
        * As we enable CTS interrupts only if we have CRTSCTS or CDTRCTS,
        * this code also effectively turns off ZSWR15_CTS_IE.
        *
        * Also, disable DCD interrupts if we've been told to ignore
        * the DCD pin. Happens on mac68k because the input line for
        * DCD can also be used as a clock input.  (Just set CLOCAL.)
        *
        * If someone tries to turn an invalid flow mode on, Just Say No
        * (Suggested by gwr)
        */
       if ((cflag & CDTRCTS) && (cflag & (CRTSCTS | MDMBUF)))
               return (EINVAL);
       cs->cs_rr0_pps = 0;
       if (xcs->cs_hwflags & ZS_HWFLAG_NO_DCD) {
               if (cflag & MDMBUF)
                       return (EINVAL);
               cflag |= CLOCAL;
       } else {
               /*
                * cs->cs_rr0_pps indicates which bit MAY be used for pps.
                * Enable only if nothing else will want the interrupt and
                * it's ok to enable interrupts on this line.
                */
               if ((cflag & (CLOCAL | MDMBUF)) == CLOCAL)
                       cs->cs_rr0_pps = ZSRR0_DCD;
       }
       if ((xcs->cs_hwflags & ZS_HWFLAG_NO_CTS) && (cflag & (CRTSCTS | CDTRCTS)))
               return (EINVAL);

       /*
        * 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 = splzs();
       if ((cflag & (CLOCAL | MDMBUF)) != 0)
               cs->cs_rr0_dcd = 0;
       else
               cs->cs_rr0_dcd = ZSRR0_DCD;
       /*
        * The mac hardware only has one output, DTR (HSKo in Mac
        * parlance). In HFC mode, we use it for the functions
        * typically served by RTS and DTR on other ports, so we
        * have to fake the upper layer out some.
        *
        * CRTSCTS we use CTS as an input which tells us when to shut up.
        * We make no effort to shut up the other side of the connection.
        * DTR is used to hang up the modem.
        *
        * In CDTRCTS, we use CTS to tell us to stop, but we use DTR to
        * shut up the other side.
        */
       if ((cflag & CRTSCTS) != 0) {
               cs->cs_wr5_dtr = ZSWR5_DTR;
               cs->cs_wr5_rts = 0;
               cs->cs_rr0_cts = ZSRR0_CTS;
       } else if ((cflag & CDTRCTS) != 0) {
               cs->cs_wr5_dtr = 0;
               cs->cs_wr5_rts = ZSWR5_DTR;
               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;
               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.
* MacII hardware has the delay built in.
* No need for extra delay. :-) However, some clock-chirped
* macs, or zsc's on serial add-on boards might need it.
*/
#define ZS_DELAY()

uint8_t
zs_read_reg(struct zs_chanstate *cs, uint8_t reg)
{
       uint8_t val;

       *cs->cs_reg_csr = reg;
       ZS_DELAY();
       val = *cs->cs_reg_csr;
       ZS_DELAY();
       return val;
}

void
zs_write_reg(struct zs_chanstate *cs, uint8_t reg, uint8_t val)
{
       *cs->cs_reg_csr = reg;
       ZS_DELAY();
       *cs->cs_reg_csr = val;
       ZS_DELAY();
}

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

       val = *cs->cs_reg_csr;
       ZS_DELAY();
       /* make up for the fact CTS is wired backwards */
       val ^= ZSRR0_CTS;
       return val;
}

void
zs_write_csr(struct zs_chanstate *cs, uint8_t val)
{
       /* Note, the csr does not write CTS... */
       *cs->cs_reg_csr = val;
       ZS_DELAY();
}

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

       val = *cs->cs_reg_data;
       ZS_DELAY();
       return val;
}

void
zs_write_data(struct zs_chanstate *cs, uint8_t val)
{
       *cs->cs_reg_data = val;
       ZS_DELAY();
}

/****************************************************************
* Console support functions (mac68k specific!)
* Note: this code is allowed to know about the layout of
* the chip registers, and uses that to keep things simple.
* XXX - I think I like the mvme167 code better. -gwr
* XXX - Well :-P  :-)  -wrs
****************************************************************/

#define zscnpollc       nullcnpollc
cons_decl(zs);

static void     zscnsetup(void);

/*
* Console functions.
*/

/*
* This code modeled after the zs_setparam routine in zskgdb
* It sets the console unit to a known state so we can output
* correctly.
*/
static void
zscnsetup(void)
{
       struct xzs_chanstate xcs;
       struct zs_chanstate *cs;
       struct zschan *zc;
       int tconst, s;

       /* Setup temporary chanstate. */
       memset(&xcs, 0, sizeof(xcs));
       cs = &xcs.xzs_cs;
       zc = zs_conschan;
       cs->cs_reg_csr  = &zc->zc_csr;
       cs->cs_reg_data = &zc->zc_data;
       cs->cs_channel = zs_consunit;
       cs->cs_brg_clk = PCLK / 16;

       memcpy(cs->cs_preg, zs_init_reg, 16);
       cs->cs_preg[5] |= ZSWR5_DTR | ZSWR5_RTS;
       cs->cs_preg[15] = ZSWR15_BREAK_IE;
       tconst = BPS_TO_TCONST(cs->cs_brg_clk, zs_defspeed[zs_consunit]);
       cs->cs_preg[12] = tconst;
       cs->cs_preg[13] = tconst >> 8;
       /* can't use zs_set_speed as we haven't set up the
        * signal sources, and it's not worth it for now
        */

       /*
        * As zs_loadchannelregs doesn't touch reg 9 (interrupt control),
        * we won't accidentally turn on interrupts below
        */
       s = splhigh();
       zs_loadchannelregs(cs);
       splx(s);
}

/*
* zscnprobe is the routine which gets called as the kernel is trying to
* figure out where the console should be. Each io driver which might
* be the console (as defined in mac68k/conf.c) gets probed. The probe
* fills in the consdev structure. Important parts are the device #,
* and the console priority. Values are CN_DEAD (don't touch me),
* CN_NORMAL (I'm here, but elsewhere might be better), CN_INTERNAL
* (the video, better than CN_NORMAL), and CN_REMOTE (pick me!)
*
* As the mac's a bit different, we do extra work here. We mainly check
* to see if we have serial echo going on. Also chould check for default
* speeds.
*/
void
zscnprobe(struct consdev * cp)
{
       extern u_long   IOBase;
       int     maj, unit, i;
       extern const struct cdevsw zstty_cdevsw;

       maj = cdevsw_lookup_major(&zstty_cdevsw);
       if (maj != -1) {
               cp->cn_pri = CN_NORMAL;          /* Lower than CN_INTERNAL */
               if (mac68k_machine.serial_console != 0) {
                       cp->cn_pri = CN_REMOTE;  /* Higher than CN_INTERNAL */
                       mac68k_machine.serial_boot_echo =0;
               }

               unit = (mac68k_machine.serial_console == 1) ? 0 : 1;
               zs_consunit = unit;
               zs_conschan = (struct zschan *) -1; /* dummy flag for zs_init() */

               mac68k_zsdev = cp->cn_dev = makedev(maj, unit);
       }
       if (mac68k_machine.serial_boot_echo) {
               /*
                * at this point, we know that we don't have a serial
                * console, but are doing echo
                */
               zs_conschan = (struct zschan *) -1; /* dummy flag for zs_init() */
               zs_consunit = 1;
               zs_hwflags[zs_consunit] = ZS_HWFLAG_CONSOLE;
       }

       if ((i = mac68k_machine.modem_d_speed) > 0) {
               if (zs_cn_check_speed(i))
                       zs_defspeed[0] = i;
       }
       if ((i = mac68k_machine.print_d_speed) > 0) {
               if (zs_cn_check_speed(i))
                       zs_defspeed[1] = i;
       }
       mac68k_set_io_offsets(IOBase);
       zs_init();
       /*
        * zsinit will set up the addresses of the scc. It will also, if
        * zs_conschan != 0, calculate the new address of the conschan for
        * unit zs_consunit. So if we are (or think we are) going to use the
        * chip for console I/O, we just set up the internal addresses for it.
        *
        * Now turn off interrupts for the chip. Note: using sccA to get at
        * the chip is the only vestige of the NetBSD 1.0 ser driver. :-)
        */
       unit = sccA[2];                 /* reset reg. access */
       unit = sccA[0];
       sccA[2] = 9; sccA[2] = 0;       /* write 0 to reg. 9, clearing MIE */
       sccA[2] = ZSWR0_CLR_INTR; unit = sccA[2]; /* reset any pending ints. */
       sccA[0] = ZSWR0_CLR_INTR; unit = sccA[0];

       if (mac68k_machine.serial_boot_echo)
               zscnsetup();
       return;
}

void
zscninit(struct consdev *cp)
{

       zs_hwflags[zs_consunit] = ZS_HWFLAG_CONSOLE;

       /*
        * zsinit will set up the addresses of the scc. It will also, if
        * zs_conschan != 0, calculate the new address of the conschan for
        * unit zs_consunit. So zs_init implicitly sets zs_conschan to the right
        * number. :-)
        */
       zscnsetup();
       printf("\nNetBSD/mac68k console\n");
}


/*
* Polled input char.
*/
int
zs_getc(void *arg)
{
       volatile struct zschan *zc = arg;
       int s, c, rr0;

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

       c = zc->zc_data;
       ZS_DELAY();
       splx(s);

       /*
        * This is 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)
{
       volatile struct zschan *zc = arg;
       int s, rr0;
       long wait = 0;

       s = splhigh();
       /* Wait for transmitter to become ready. */
       do {
               rr0 = zc->zc_csr;
               ZS_DELAY();
       } while (((rr0 & ZSRR0_TX_READY) == 0) && (wait++ < 1000000));

       if ((rr0 & ZSRR0_TX_READY) != 0) {
               zc->zc_data = c;
               ZS_DELAY();
       }
       splx(s);
}


/*
* Polled console input putchar.
*/
int
zscngetc(dev_t dev)
{
       struct zschan *zc = zs_conschan;
       int c;

       c = zs_getc(zc);
       return (c);
}

/*
* Polled console output putchar.
*/
void
zscnputc(dev_t dev, int c)
{
       struct zschan *zc = zs_conschan;

       zs_putc(zc, c);
}



/*
* Handle user request to enter kernel debugger.
*/
void
zs_abort(struct zs_chanstate *cs)
{
       volatile struct zschan *zc = zs_conschan;
       int rr0;
       long wait = 0;

       if (zs_cons_canabort == 0)
               return;

       /* Wait for end of break to avoid PROM abort. */
       do {
               rr0 = zc->zc_csr;
               ZS_DELAY();
       } while ((rr0 & ZSRR0_BREAK) && (wait++ < ZSABORT_DELAY));

       if (wait > ZSABORT_DELAY) {
               zs_cons_canabort = 0;
       /* If we time out, turn off the abort ability! */
       }

#ifdef DDB
       Debugger();
#endif
}