Linux 2.4.0-test10pre4

[davej-history.git] / drivers / sbus / char / zs.c

/* $Id: zs.c,v 1.60 2000/10/14 10:09:04 davem Exp $
 * zs.c: Zilog serial port driver for the Sparc.
 *
 * Copyright (C) 1995 David S. Miller (davem@caip.rutgers.edu)
 * Copyright (C) 1996 Eddie C. Dost   (ecd@skynet.be)
 * Fixes by Pete A. Zaitcev <zaitcev@metabyte.com>.
 */

#include <linux/errno.h>
#include <linux/signal.h>
#include <linux/sched.h>
#include <linux/timer.h>
#include <linux/interrupt.h>
#include <linux/tty.h>
#include <linux/tty_flip.h>
#include <linux/config.h>
#include <linux/major.h>
#include <linux/string.h>
#include <linux/fcntl.h>
#include <linux/mm.h>
#include <linux/kernel.h>
#include <linux/keyboard.h>
#include <linux/console.h>
#include <linux/delay.h>
#include <linux/init.h>
#include <linux/bootmem.h>
#include <linux/sysrq.h>

#include <asm/io.h>
#include <asm/irq.h>
#include <asm/oplib.h>
#include <asm/system.h>
#include <asm/uaccess.h>
#include <asm/bitops.h>
#include <asm/kdebug.h>
#include <asm/page.h>
#include <asm/pgtable.h>

#include <asm/sbus.h>
#ifdef __sparc_v9__
#include <asm/fhc.h>
#endif
#ifdef CONFIG_PCI
#include <linux/pci.h>
#endif

#include "sunserial.h"
#include "zs.h"
#include "sunkbd.h"
#include "sunmouse.h"

static int num_serial = 2; /* sun4/sun4c/sun4m - Two chips on board. */
#define NUM_SERIAL num_serial
#define NUM_CHANNELS (NUM_SERIAL * 2)

#define KEYBOARD_LINE 0x2
#define MOUSE_LINE    0x3

/* On 32-bit sparcs we need to delay after register accesses
 * to accomodate sun4 systems, but we do not need to flush writes.
 * On 64-bit sparc we only need to flush single writes to ensure
 * completion.
 */
#ifndef __sparc_v9__
#define ZSDELAY()               udelay(5)
#define ZSDELAY_LONG()          udelay(20)
#define ZS_WSYNC(channel)       do { } while(0)
#else
#define ZSDELAY()
#define ZSDELAY_LONG()
#define ZS_WSYNC(__channel) \
        sbus_readb(&((__channel)->control))
#endif

struct sun_zslayout **zs_chips;
struct sun_zschannel **zs_channels;
struct sun_zschannel *zs_mousechan;
struct sun_zschannel *zs_kbdchan;
struct sun_zschannel *zs_kgdbchan;
int *zs_nodes;

struct sun_serial *zs_soft;
struct sun_serial *zs_chain;  /* IRQ servicing chain */
int zilog_irq;

struct tty_struct *zs_ttys;

/* Console hooks... */
#ifdef CONFIG_SERIAL_CONSOLE
static struct console zs_console;
static int zs_console_init(void);

/*
 * Define this to get the zs_fair_output() functionality.
 */
#undef SERIAL_CONSOLE_FAIR_OUTPUT
#endif /* CONFIG_SERIAL_CONSOLE */

static unsigned char kgdb_regs[16] = {
        0, 0, 0,                     /* write 0, 1, 2 */
        (Rx8 | RxENAB),              /* write 3 */
        (X16CLK | SB1 | PAR_EVEN),   /* write 4 */
        (DTR | Tx8 | TxENAB),        /* write 5 */
        0, 0, 0,                     /* write 6, 7, 8 */
        (NV),                        /* write 9 */
        (NRZ),                       /* write 10 */
        (TCBR | RCBR),               /* write 11 */
        0, 0,                        /* BRG time constant, write 12 + 13 */
        (BRSRC | BRENAB),            /* write 14 */
        (DCDIE)                      /* write 15 */
};

static unsigned char zscons_regs[16] = {
        0,                           /* write 0 */
        (EXT_INT_ENAB | INT_ALL_Rx), /* write 1 */
        0,                           /* write 2 */
        (Rx8 | RxENAB),              /* write 3 */
        (X16CLK),                    /* write 4 */
        (DTR | Tx8 | TxENAB),        /* write 5 */
        0, 0, 0,                     /* write 6, 7, 8 */
        (NV | MIE),                  /* write 9 */
        (NRZ),                       /* write 10 */
        (TCBR | RCBR),               /* write 11 */
        0, 0,                        /* BRG time constant, write 12 + 13 */
        (BRSRC | BRENAB),            /* write 14 */
        (DCDIE | CTSIE | TxUIE | BRKIE) /* write 15 */
};

#define ZS_CLOCK         4915200   /* Zilog input clock rate */

DECLARE_TASK_QUEUE(tq_serial);

static struct tty_driver serial_driver, callout_driver;
static int serial_refcount;

/* serial subtype definitions */
#define SERIAL_TYPE_NORMAL      1
#define SERIAL_TYPE_CALLOUT     2
  
/* number of characters left in xmit buffer before we ask for more */
#define WAKEUP_CHARS 256

#define SERIAL_DO_RESTART

/* Debugging... DEBUG_INTR is bad to use when one of the zs
 * lines is your console ;(
 */
#undef SERIAL_DEBUG_INTR
#undef SERIAL_DEBUG_OPEN
#undef SERIAL_DEBUG_FLOW

#define RS_STROBE_TIME 10
#define RS_ISR_PASS_LIMIT 256

#define _INLINE_ inline

int zs_init(void);
static void zs_kgdb_hook(int);

static void change_speed(struct sun_serial *info);

static struct tty_struct **serial_table;
static struct termios **serial_termios;
static struct termios **serial_termios_locked;

#ifndef MIN
#define MIN(a,b)        ((a) < (b) ? (a) : (b))
#endif

#undef ZS_LOG
#ifdef ZS_LOG
struct zs_logent {
        u8 reg, val;
        u8 write, __pad;
#define REGIRQ  0xff
#define REGDATA 0xfe
#define REGCTRL 0xfd
};
struct zs_logent zslog[32];
int zs_curlog = 0;
#define ZSLOG(__reg, __val, __write) \
do{     int index = zs_curlog; \
        zslog[index].reg = (__reg); \
        zslog[index].val = (__val); \
        zslog[index].write = (__write); \
        zs_curlog = (index + 1) & (32 - 1); \
}while(0)
int zs_dumplog(char *buffer)
{
        int len = 0;
        int i;

        for (i = 0; i < 32; i++) {
                u8 reg, val, write;

                reg = zslog[i].reg;
                val = zslog[i].val;
                write = zslog[i].write;
                len += sprintf(buffer + len,
                               "ZSLOG[%2d]: reg %2x val %2x %s\n",
                               i, reg, val, write ? "write" : "read");
        }
        len += sprintf(buffer + len, "ZS current log index %d\n",
                       zs_curlog);
        return len;
}
#else
#define ZSLOG(x,y,z)    do { } while (0)
#endif

/*
 * tmp_buf is used as a temporary buffer by serial_write.  We need to
 * lock it in case the memcpy_fromfs blocks while swapping in a page,
 * and some other program tries to do a serial write at the same time.
 * Since the lock will only come under contention when the system is
 * swapping and available memory is low, it makes sense to share one
 * buffer across all the serial ports, since it significantly saves
 * memory if large numbers of serial ports are open.
 */
static unsigned char tmp_buf[4096]; /* This is cheating */
static DECLARE_MUTEX(tmp_buf_sem);

static inline int serial_paranoia_check(struct sun_serial *info,
                                        dev_t device, const char *routine)
{
#ifdef SERIAL_PARANOIA_CHECK
        static const char *badmagic =
                "Warning: bad magic number for serial struct (%d, %d) in %s\n";
        static const char *badinfo =
                "Warning: null sun_serial for (%d, %d) in %s\n";

        if (!info) {
                printk(badinfo, MAJOR(device), MINOR(device), routine);
                return 1;
        }
        if (info->magic != SERIAL_MAGIC) {
                printk(badmagic, MAJOR(device), MINOR(device), routine);
                return 1;
        }
#endif
        return 0;
}

/* This is used to figure out the divisor speeds and the timeouts. */
static int baud_table[] = {
        0, 50, 75, 110, 134, 150, 200, 300, 600, 1200, 1800, 2400, 4800,
        9600, 19200, 38400, 76800, 0
};

/* Reading and writing Zilog8530 registers.  The delays are to make this
 * driver work on the Sun4 which needs a settling delay after each chip
 * register access, other machines handle this in hardware via auxiliary
 * flip-flops which implement the settle time we do in software.
 */
static inline unsigned char read_zsreg(struct sun_zschannel *channel,
                                       unsigned char reg)
{
        unsigned char retval;

        sbus_writeb(reg, &channel->control);
        ZSDELAY();
        retval = sbus_readb(&channel->control);
        ZSDELAY();
        ZSLOG(reg, retval, 0);
        return retval;
}

static inline void write_zsreg(struct sun_zschannel *channel,
                               unsigned char reg, unsigned char value)
{
        ZSLOG(reg, value, 1);
        sbus_writeb(reg, &channel->control);
        ZSDELAY();
        sbus_writeb(value, &channel->control);
        ZSDELAY();
}

static inline void load_zsregs(struct sun_serial *info, unsigned char *regs)
{
        struct sun_zschannel *channel = info->zs_channel;
        unsigned long flags;
        unsigned char stat;
        int i;

        for (i = 0; i < 1000; i++) {
                stat = read_zsreg(channel, R1);
                if (stat & ALL_SNT)
                        break;
                udelay(100);
        }
        write_zsreg(channel, R3, 0);
        ZS_CLEARSTAT(channel);
        ZS_CLEARERR(channel);
        ZS_CLEARFIFO(channel);

        /* Load 'em up */
        save_flags(flags); cli();
        if (info->channelA)
                write_zsreg(channel, R9, CHRA);
        else
                write_zsreg(channel, R9, CHRB);
        ZSDELAY_LONG();
        write_zsreg(channel, R4, regs[R4]);
        write_zsreg(channel, R3, regs[R3] & ~RxENAB);
        write_zsreg(channel, R5, regs[R5] & ~TxENAB);
        write_zsreg(channel, R9, regs[R9] & ~MIE);
        write_zsreg(channel, R10, regs[R10]);
        write_zsreg(channel, R11, regs[R11]);
        write_zsreg(channel, R12, regs[R12]);
        write_zsreg(channel, R13, regs[R13]);
        write_zsreg(channel, R14, regs[R14] & ~BRENAB);
        write_zsreg(channel, R14, regs[R14]);
        write_zsreg(channel, R14, (regs[R14] & ~SNRZI) | BRENAB);
        write_zsreg(channel, R3, regs[R3]);
        write_zsreg(channel, R5, regs[R5]);
        write_zsreg(channel, R15, regs[R15]);
        write_zsreg(channel, R0, RES_EXT_INT);
        write_zsreg(channel, R0, ERR_RES);
        write_zsreg(channel, R1, regs[R1]);
        write_zsreg(channel, R9, regs[R9]);
        restore_flags(flags);
}

#define ZS_PUT_CHAR_MAX_DELAY   2000    /* 10 ms */

static inline void zs_put_char(struct sun_zschannel *channel, char ch)
{
        int loops = ZS_PUT_CHAR_MAX_DELAY;

        /* Do not change this to use ZSDELAY as this is
         * a timed polling loop and on sparc64 ZSDELAY
         * is a nop.  -DaveM
         */
        do {
                u8 val = sbus_readb(&channel->control);
                ZSLOG(REGCTRL, val, 0);
                if (val & Tx_BUF_EMP)
                        break;
                udelay(5);
        } while (--loops);

        sbus_writeb(ch, &channel->data);
        ZSDELAY();
        ZS_WSYNC(channel);
        ZSLOG(REGDATA, ch, 1);
}

/* Sets or clears DTR/RTS on the requested line */
static inline void zs_rtsdtr(struct sun_serial *ss, int set)
{
        unsigned long flags;

        save_flags(flags); cli();
        if(set) {
                ss->curregs[5] |= (RTS | DTR);
                write_zsreg(ss->zs_channel, 5, ss->curregs[5]);
        } else {
                ss->curregs[5] &= ~(RTS | DTR);
                write_zsreg(ss->zs_channel, 5, ss->curregs[5]);
        }
        restore_flags(flags);
        return;
}

static inline void kgdb_chaninit(struct sun_serial *ss, int intson, int bps)
{
        int brg;

        if(intson) {
                kgdb_regs[R1] = INT_ALL_Rx;
                kgdb_regs[R9] |= MIE;
        } else {
                kgdb_regs[R1] = 0;
                kgdb_regs[R9] &= ~MIE;
        }
        brg = BPS_TO_BRG(bps, ZS_CLOCK/16);
        kgdb_regs[R12] = (brg & 255);
        kgdb_regs[R13] = ((brg >> 8) & 255);
        load_zsregs(ss, kgdb_regs);
}

/*
 * ------------------------------------------------------------
 * zs_stop() and zs_start()
 *
 * This routines are called before setting or resetting tty->stopped.
 * They enable or disable transmitter interrupts, as necessary.
 * ------------------------------------------------------------
 */
static void zs_stop(struct tty_struct *tty)
{
        struct sun_serial *info = (struct sun_serial *) tty->driver_data;
        unsigned long flags;

        if (serial_paranoia_check(info, tty->device, "zs_stop"))
                return;
        
        save_flags(flags); cli();
        if (info->curregs[5] & TxENAB) {
                info->curregs[5] &= ~TxENAB;
                write_zsreg(info->zs_channel, 5, info->curregs[5]);
        }
        restore_flags(flags);
}

static void zs_start(struct tty_struct *tty)
{
        struct sun_serial *info = (struct sun_serial *) tty->driver_data;
        unsigned long flags;
        
        if (serial_paranoia_check(info, tty->device, "zs_start"))
                return;
        
        save_flags(flags); cli();
        if (info->xmit_cnt && info->xmit_buf && !(info->curregs[5] & TxENAB)) {
                info->curregs[5] |= TxENAB;
                write_zsreg(info->zs_channel, 5, info->curregs[5]);
        }
        restore_flags(flags);
}

/* Drop into either the boot monitor or kadb upon receiving a break
 * from keyboard/console input.
 */
void batten_down_hatches(void)
{
        if (!stop_a_enabled)
                return;
        /* If we are doing kadb, we call the debugger
         * else we just drop into the boot monitor.
         * Note that we must flush the user windows
         * first before giving up control.
         */
        printk("\n");
        flush_user_windows();
#ifndef __sparc_v9__
        if((((unsigned long)linux_dbvec)>=DEBUG_FIRSTVADDR) &&
           (((unsigned long)linux_dbvec)<=DEBUG_LASTVADDR))
                sp_enter_debugger();
        else
#endif
                prom_cmdline();

        /* XXX We want to notify the keyboard driver that all
         * XXX keys are in the up state or else weird things
         * XXX happen...
         */

        return;
}


/*
 * ----------------------------------------------------------------------
 *
 * Here starts the interrupt handling routines.  All of the following
 * subroutines are declared as inline and are folded into
 * zs_interrupt().  They were separated out for readability's sake.
 *
 * Note: zs_interrupt() is a "fast" interrupt, which means that it
 * runs with interrupts turned off.  People who may want to modify
 * zs_interrupt() should try to keep the interrupt handler as fast as
 * possible.  After you are done making modifications, it is not a bad
 * idea to do:
 * 
 * gcc -S -DKERNEL -Wall -Wstrict-prototypes -O6 -fomit-frame-pointer serial.c
 *
 * and look at the resulting assemble code in serial.s.
 *
 *                              - Ted Ts'o (tytso@mit.edu), 7-Mar-93
 * -----------------------------------------------------------------------
 */

/*
 * This routine is used by the interrupt handler to schedule
 * processing in the software interrupt portion of the driver.
 */
static _INLINE_ void zs_sched_event(struct sun_serial *info,
                                    int event)
{
        info->event |= 1 << event;
        queue_task(&info->tqueue, &tq_serial);
        mark_bh(SERIAL_BH);
}

#ifndef __sparc_v9__
extern void breakpoint(void);  /* For the KGDB frame character */
#endif

static _INLINE_ void receive_chars(struct sun_serial *info, struct pt_regs *regs)
{
        struct tty_struct *tty = info->tty;
        unsigned char ch, stat;
        int do_queue_task = 1;

        do {
                ch = sbus_readb(&info->zs_channel->data);
                ZSLOG(REGDATA, ch, 0);
                ch &= info->parity_mask;
                ZSDELAY();

                /* If this is the console keyboard, we need to handle
                 * L1-A's here.
                 */
                if(info->cons_keyb) {
                        if(ch == SUNKBD_RESET) {
                                l1a_state.kbd_id = 1;
                                l1a_state.l1_down = 0;
                        } else if(l1a_state.kbd_id) {
                                l1a_state.kbd_id = 0;
                        } else if(ch == SUNKBD_L1) {
                                l1a_state.l1_down = 1;
                        } else if(ch == (SUNKBD_L1|SUNKBD_UP)) {
                                l1a_state.l1_down = 0;
                        } else if(ch == SUNKBD_A && l1a_state.l1_down) {
                                /* whee... */
                                batten_down_hatches();
                                /* Continue execution... */
                                l1a_state.l1_down = 0;
                                l1a_state.kbd_id = 0;
                                return;
                        }
                        sunkbd_inchar(ch, regs);
                        do_queue_task = 0;
                        goto next_char;
                }
                if(info->cons_mouse) {
                        sun_mouse_inbyte(ch, 0);
                        do_queue_task = 0;
                        goto next_char;
                }
                if(info->is_cons) {
                        if(ch == 0) {
                                /* whee, break received */
                                batten_down_hatches();
                                /* Continue execution... */
                                return;
                        }
                        /* It is a 'keyboard interrupt' ;-) */
                        wake_up(&keypress_wait);
                }
#ifndef __sparc_v9__
                /* Look for kgdb 'stop' character, consult the gdb
                 * documentation for remote target debugging and
                 * arch/sparc/kernel/sparc-stub.c to see how all this works.
                 */
                if((info->kgdb_channel) && (ch =='\003')) {
                        breakpoint();
                        return;
                }
#endif
                if(!tty)
                        return;

                if (tty->flip.count >= TTY_FLIPBUF_SIZE)
                        break;

                tty->flip.count++;
                *tty->flip.flag_buf_ptr++ = 0;
                *tty->flip.char_buf_ptr++ = ch;

        next_char:
                /* Check if we have another character... */
                stat = sbus_readb(&info->zs_channel->control);
                ZSDELAY();
                ZSLOG(REGCTRL, stat, 0);
                if (!(stat & Rx_CH_AV))
                        break;

                /* ... and see if it is clean. */
                stat = read_zsreg(info->zs_channel, R1);
        } while (!(stat & (PAR_ERR | Rx_OVR | CRC_ERR)));

        if (do_queue_task != 0)
                queue_task(&tty->flip.tqueue, &tq_timer);
}

static _INLINE_ void transmit_chars(struct sun_serial *info)
{
        struct tty_struct *tty = info->tty;

        if (info->x_char) {
                /* Send next char */
                zs_put_char(info->zs_channel, info->x_char);
                info->x_char = 0;
                return;
        }

        if((info->xmit_cnt <= 0) || (tty != 0 && tty->stopped)) {
                /* That's peculiar... */
                sbus_writeb(RES_Tx_P, &info->zs_channel->control);
                ZSDELAY();
                ZS_WSYNC(info->zs_channel);
                ZSLOG(REGCTRL, RES_Tx_P, 1);
                return;
        }

        /* Send char */
        zs_put_char(info->zs_channel, info->xmit_buf[info->xmit_tail++]);
        info->xmit_tail = info->xmit_tail & (SERIAL_XMIT_SIZE-1);
        info->xmit_cnt--;

        if (info->xmit_cnt < WAKEUP_CHARS)
                zs_sched_event(info, RS_EVENT_WRITE_WAKEUP);

        if(info->xmit_cnt <= 0) {
                sbus_writeb(RES_Tx_P, &info->zs_channel->control);
                ZSDELAY();
                ZS_WSYNC(info->zs_channel);
                ZSLOG(REGCTRL, RES_Tx_P, 1);
        }
}

static _INLINE_ void status_handle(struct sun_serial *info)
{
        unsigned char status;

        /* Get status from Read Register 0 */
        status = sbus_readb(&info->zs_channel->control);
        ZSDELAY();
        ZSLOG(REGCTRL, status, 0);
        /* Clear status condition... */
        sbus_writeb(RES_EXT_INT, &info->zs_channel->control);
        ZSDELAY();
        ZS_WSYNC(info->zs_channel);
        ZSLOG(REGCTRL, RES_EXT_INT, 1);
#if 0
        if(status & DCD) {
                if((info->tty->termios->c_cflag & CRTSCTS) &&
                   ((info->curregs[3] & AUTO_ENAB)==0)) {
                        info->curregs[3] |= AUTO_ENAB;
                        write_zsreg(info->zs_channel, 3, info->curregs[3]);
                }
        } else {
                if((info->curregs[3] & AUTO_ENAB)) {
                        info->curregs[3] &= ~AUTO_ENAB;
                        write_zsreg(info->zs_channel, 3, info->curregs[3]);
                }
        }
#endif
        /* Whee, if this is console input and this is a
         * 'break asserted' status change interrupt, call
         * the boot prom.
         */
        if(status & BRK_ABRT) {
                if (info->break_abort)
                        batten_down_hatches();
                if (info->cons_mouse)
                        sun_mouse_inbyte(0, 1);
        }

        /* XXX Whee, put in a buffer somewhere, the status information
         * XXX whee whee whee... Where does the information go...
         */
        return;
}

static _INLINE_ void special_receive(struct sun_serial *info)
{
        struct tty_struct *tty = info->tty;
        unsigned char ch, stat;

        stat = read_zsreg(info->zs_channel, R1);
        if (stat & (PAR_ERR | Rx_OVR | CRC_ERR)) {
                ch = sbus_readb(&info->zs_channel->data);
                ZSDELAY();
                ZSLOG(REGDATA, ch, 0);
        }

        if (!tty)
                goto clear;

        if (tty->flip.count >= TTY_FLIPBUF_SIZE)
                goto done;

        tty->flip.count++;
        if(stat & PAR_ERR)
                *tty->flip.flag_buf_ptr++ = TTY_PARITY;
        else if(stat & Rx_OVR)
                *tty->flip.flag_buf_ptr++ = TTY_OVERRUN;
        else if(stat & CRC_ERR)
                *tty->flip.flag_buf_ptr++ = TTY_FRAME;

done:
        queue_task(&tty->flip.tqueue, &tq_timer);
clear:
        sbus_writeb(ERR_RES, &info->zs_channel->control);
        ZSDELAY();
        ZS_WSYNC(info->zs_channel);
        ZSLOG(REGCTRL, ERR_RES, 1);
}


/*
 * This is the serial driver's generic interrupt routine
 */
void zs_interrupt(int irq, void *dev_id, struct pt_regs * regs)
{
        struct sun_serial *info;
        unsigned char zs_intreg;
        int i;

        info = (struct sun_serial *)dev_id;
        ZSLOG(REGIRQ, 0, 0);
        for (i = 0; i < NUM_SERIAL; i++) {
                zs_intreg = read_zsreg(info->zs_next->zs_channel, 2);
                zs_intreg &= STATUS_MASK;

                /* NOTE: The read register 2, which holds the irq status,
                 *       does so for both channels on each chip.  Although
                 *       the status value itself must be read from the B
                 *       channel and is only valid when read from channel B.
                 *       When read from channel A, read register 2 contains
                 *       the value written to write register 2.
                 */

                /* Channel A -- /dev/ttya or /dev/kbd, could be the console */
                if (zs_intreg == CHA_Rx_AVAIL) {
                        receive_chars(info, regs);
                        return;
                }
                if(zs_intreg == CHA_Tx_EMPTY) {
                        transmit_chars(info);
                        return;
                }
                if (zs_intreg == CHA_EXT_STAT) {
                        status_handle(info);
                        return;
                }
                if (zs_intreg == CHA_SPECIAL) {
                        special_receive(info);
                        return;
                }

                /* Channel B -- /dev/ttyb or /dev/mouse, could be the console */
                if(zs_intreg == CHB_Rx_AVAIL) {
                        receive_chars(info->zs_next, regs);
                        return;
                }
                if(zs_intreg == CHB_Tx_EMPTY) {
                        transmit_chars(info->zs_next);
                        return;
                }
                if (zs_intreg == CHB_EXT_STAT) {
                        status_handle(info->zs_next);
                        return;
                }

                /* NOTE: The default value for the IRQ status in read register
                 *       2 in channel B is CHB_SPECIAL, so we need to look at
                 *       read register 3 in channel A to check if this is a
                 *       real interrupt, or just the default value.
                 *       Yes... broken hardware...
                 */

                zs_intreg = read_zsreg(info->zs_channel, 3);
                if (zs_intreg & CHBRxIP) {
                        special_receive(info->zs_next);
                        return;
                }
                info = info->zs_next->zs_next;
        }
}

/*
 * -------------------------------------------------------------------
 * Here ends the serial interrupt routines.
 * -------------------------------------------------------------------
 */

/*
 * This routine is used to handle the "bottom half" processing for the
 * serial driver, known also the "software interrupt" processing.
 * This processing is done at the kernel interrupt level, after the
 * zs_interrupt() has returned, BUT WITH INTERRUPTS TURNED ON.  This
 * is where time-consuming activities which can not be done in the
 * interrupt driver proper are done; the interrupt driver schedules
 * them using zs_sched_event(), and they get done here.
 */
static void do_serial_bh(void)
{
        run_task_queue(&tq_serial);
}

static void do_softint(void *private_)
{
        struct sun_serial       *info = (struct sun_serial *) private_;
        struct tty_struct       *tty;
        
        tty = info->tty;
        if (!tty)
                return;

        if (test_and_clear_bit(RS_EVENT_WRITE_WAKEUP, &info->event)) {
                if ((tty->flags & (1 << TTY_DO_WRITE_WAKEUP)) &&
                    tty->ldisc.write_wakeup)
                        (tty->ldisc.write_wakeup)(tty);
                wake_up_interruptible(&tty->write_wait);
        }
}

/*
 * This routine is called from the scheduler tqueue when the interrupt
 * routine has signalled that a hangup has occurred.  The path of
 * hangup processing is:
 *
 *      serial interrupt routine -> (scheduler tqueue) ->
 *      do_serial_hangup() -> tty->hangup() -> zs_hangup()
 * 
 */
static void do_serial_hangup(void *private_)
{
        struct sun_serial       *info = (struct sun_serial *) private_;
        struct tty_struct       *tty;
        
        tty = info->tty;
        if (!tty)
                return;
#ifdef SERIAL_DEBUG_OPEN
        printk("do_serial_hangup<%p: tty-%d\n",
                __builtin_return_address(0), info->line);
#endif

        tty_hangup(tty);
}

static int startup(struct sun_serial * info)
{
        unsigned long flags;

        if (info->flags & ZILOG_INITIALIZED)
                return 0;

        if (!info->xmit_buf) {
                info->xmit_buf = (unsigned char *) get_free_page(GFP_KERNEL);
                if (!info->xmit_buf)
                        return -ENOMEM;
        }

        save_flags(flags); cli();

#ifdef SERIAL_DEBUG_OPEN
        printk("Starting up tty-%d (irq %d)...\n", info->line, info->irq);
#endif

        /*
         * Clear the FIFO buffers and disable them
         * (they will be reenabled in change_speed())
         */
        ZS_CLEARFIFO(info->zs_channel);
        info->xmit_fifo_size = 1;

        /*
         * Clear the interrupt registers.
         */
        sbus_writeb(ERR_RES, &info->zs_channel->control);
        ZSDELAY();
        ZS_WSYNC(info->zs_channel);
        ZSLOG(REGCTRL, ERR_RES, 1);

        sbus_writeb(RES_H_IUS, &info->zs_channel->control);
        ZSDELAY();
        ZS_WSYNC(info->zs_channel);
        ZSLOG(REGCTRL, RES_H_IUS, 1);

        /*
         * Now, initialize the Zilog
         */
        zs_rtsdtr(info, 1);

        /*
         * Finally, enable sequencing and interrupts
         */
        info->curregs[1] |= (info->curregs[1] & ~(RxINT_MASK)) |
                                (EXT_INT_ENAB | INT_ALL_Rx);
        info->curregs[3] |= (RxENAB | Rx8);
        /* We enable Tx interrupts as needed. */
        info->curregs[5] |= (TxENAB | Tx8);
        info->curregs[9] |= (NV | MIE);
        write_zsreg(info->zs_channel, 3, info->curregs[3]);
        write_zsreg(info->zs_channel, 5, info->curregs[5]);
        write_zsreg(info->zs_channel, 9, info->curregs[9]);
        
        /*
         * And clear the interrupt registers again for luck.
         */
        sbus_writeb(ERR_RES, &info->zs_channel->control);
        ZSDELAY();
        ZS_WSYNC(info->zs_channel);
        ZSLOG(REGCTRL, ERR_RES, 1);

        sbus_writeb(RES_H_IUS, &info->zs_channel->control);
        ZSDELAY();
        ZS_WSYNC(info->zs_channel);
        ZSLOG(REGCTRL, RES_H_IUS, 1);

        if (info->tty)
                clear_bit(TTY_IO_ERROR, &info->tty->flags);
        info->xmit_cnt = info->xmit_head = info->xmit_tail = 0;

        /*
         * and set the speed of the serial port
         */
        change_speed(info);

        info->flags |= ZILOG_INITIALIZED;
        restore_flags(flags);
        return 0;
}

/*
 * This routine will shutdown a serial port; interrupts are disabled, and
 * DTR is dropped if the hangup on close termio flag is on.
 */
static void shutdown(struct sun_serial * info)
{
        unsigned long   flags;

        if (!(info->flags & ZILOG_INITIALIZED))
                return;

#ifdef SERIAL_DEBUG_OPEN
        printk("Shutting down serial port %d (irq %d)....", info->line,
               info->irq);
#endif
        
        save_flags(flags); cli(); /* Disable interrupts */
        
        if (info->xmit_buf) {
                free_page((unsigned long) info->xmit_buf);
                info->xmit_buf = 0;
        }

        if (info->tty)
                set_bit(TTY_IO_ERROR, &info->tty->flags);
        
        info->flags &= ~ZILOG_INITIALIZED;
        restore_flags(flags);
}

/*
 * This routine is called to set the UART divisor registers to match
 * the specified baud rate for a serial port.
 */
static void change_speed(struct sun_serial *info)
{
        unsigned short port;
        unsigned cflag;
        int     quot = 0;
        int     i;
        int     brg;

        if (!info->tty || !info->tty->termios)
                return;
        cflag = info->tty->termios->c_cflag;
        if (!(port = info->port))
                return;
        i = cflag & CBAUD;
        if (cflag & CBAUDEX) {
                i &= ~CBAUDEX;
                if (i != 5)
                        info->tty->termios->c_cflag &= ~CBAUDEX;
                else
                        i = 16;
        }
        if (i == 15) {
                if ((info->flags & ZILOG_SPD_MASK) == ZILOG_SPD_HI)
                        i += 1;
                if ((info->flags & ZILOG_SPD_MASK) == ZILOG_SPD_CUST)
                        quot = info->custom_divisor;
        }
        if (quot) {
                info->zs_baud = info->baud_base / quot;
                info->clk_divisor = 16;

                info->curregs[4] = X16CLK;
                info->curregs[11] = TCBR | RCBR;
                brg = BPS_TO_BRG(info->zs_baud, ZS_CLOCK/info->clk_divisor);
                info->curregs[12] = (brg & 255);
                info->curregs[13] = ((brg >> 8) & 255);
                info->curregs[14] = BRSRC | BRENAB;
                zs_rtsdtr(info, 1);
        } else if (baud_table[i]) {
                info->zs_baud = baud_table[i];
                info->clk_divisor = 16;

                info->curregs[4] = X16CLK;
                info->curregs[11] = TCBR | RCBR;
                brg = BPS_TO_BRG(info->zs_baud, ZS_CLOCK/info->clk_divisor);
                info->curregs[12] = (brg & 255);
                info->curregs[13] = ((brg >> 8) & 255);
                info->curregs[14] = BRSRC | BRENAB;
                zs_rtsdtr(info, 1);
        } else {
                zs_rtsdtr(info, 0);
                return;
        }

        /* byte size and parity */
        switch (cflag & CSIZE) {
        case CS5:
                info->curregs[3] &= ~(RxN_MASK);
                info->curregs[3] |= Rx5;
                info->curregs[5] &= ~(TxN_MASK);
                info->curregs[5] |= Tx5;
                info->parity_mask = 0x1f;
                break;
        case CS6:
                info->curregs[3] &= ~(RxN_MASK);
                info->curregs[3] |= Rx6;
                info->curregs[5] &= ~(TxN_MASK);
                info->curregs[5] |= Tx6;
                info->parity_mask = 0x3f;
                break;
        case CS7:
                info->curregs[3] &= ~(RxN_MASK);
                info->curregs[3] |= Rx7;
                info->curregs[5] &= ~(TxN_MASK);
                info->curregs[5] |= Tx7;
                info->parity_mask = 0x7f;
                break;
        case CS8:
        default: /* defaults to 8 bits */
                info->curregs[3] &= ~(RxN_MASK);
                info->curregs[3] |= Rx8;
                info->curregs[5] &= ~(TxN_MASK);
                info->curregs[5] |= Tx8;
                info->parity_mask = 0xff;
                break;
        }
        info->curregs[4] &= ~(0x0c);
        if (cflag & CSTOPB) {
                info->curregs[4] |= SB2;
        } else {
                info->curregs[4] |= SB1;
        }
        if (cflag & PARENB) {
                info->curregs[4] |= PAR_ENAB;
        } else {
                info->curregs[4] &= ~PAR_ENAB;
        }
        if (!(cflag & PARODD)) {
                info->curregs[4] |= PAR_EVEN;
        } else {
                info->curregs[4] &= ~PAR_EVEN;
        }

        /* Load up the new values */
        load_zsregs(info, info->curregs);

        return;
}

/* This is for mouse/keyboard output.
 * XXX mouse output??? can we send it commands??? XXX
 */
static void kbd_put_char(unsigned char ch)
{
        struct sun_zschannel *chan = zs_kbdchan;
        unsigned long flags;

        if(!chan)
                return;

        save_flags(flags); cli();
        zs_put_char(chan, ch);
        restore_flags(flags);
}

void mouse_put_char(char ch)
{
        struct sun_zschannel *chan = zs_mousechan;
        unsigned long flags;

        if(!chan)
                return;

        save_flags(flags); cli();
        zs_put_char(chan, ch);
        restore_flags(flags);
}

/* These are for receiving and sending characters under the kgdb
 * source level kernel debugger.
 */
void putDebugChar(char kgdb_char)
{
        struct sun_zschannel *chan = zs_kgdbchan;

        while((sbus_readb(&chan->control) & Tx_BUF_EMP)==0)
                udelay(5);
        sbus_writeb(kgdb_char, &chan->data);
        ZS_WSYNC(chan);
        ZSLOG(REGDATA, kgdb_char, 1);
}

char getDebugChar(void)
{
        struct sun_zschannel *chan = zs_kgdbchan;
        u8 val;

        do {
                val = sbus_readb(&chan->control);
                ZSLOG(REGCTRL, val, 0);
                udelay(5);
        } while ((val & Rx_CH_AV) == 0);

        val = sbus_readb(&chan->data);
        ZSLOG(REGDATA, val, 0);
        return val;
}

static void zs_flush_chars(struct tty_struct *tty)
{
        struct sun_serial *info = (struct sun_serial *) tty->driver_data;
        unsigned long flags;

        if (serial_paranoia_check(info, tty->device, "zs_flush_chars"))
                return;

        save_flags(flags); cli();
        if (info->xmit_cnt <= 0 || tty->stopped || tty->hw_stopped ||
            !info->xmit_buf)
                goto out;

        /* Enable transmitter */
        info->curregs[1] |= TxINT_ENAB|EXT_INT_ENAB;
        write_zsreg(info->zs_channel, 1, info->curregs[1]);
        info->curregs[5] |= TxENAB;
        write_zsreg(info->zs_channel, 5, info->curregs[5]);

        /*
         * Send a first (bootstrapping) character. A best solution is
         * to call transmit_chars() here which handles output in a
         * generic way. Current transmit_chars() not only transmits,
         * but resets interrupts also what we do not desire here.
         * XXX Discuss with David.
         */
        zs_put_char(info->zs_channel, info->xmit_buf[info->xmit_tail++]);
        info->xmit_tail = info->xmit_tail & (SERIAL_XMIT_SIZE-1);
        info->xmit_cnt--;

out:
        restore_flags(flags);
}

static int zs_write(struct tty_struct * tty, int from_user,
                    const unsigned char *buf, int count)
{
        struct sun_serial *info = (struct sun_serial *) tty->driver_data;
        unsigned long flags;
        int c, total = 0;

        if (serial_paranoia_check(info, tty->device, "zs_write"))
                return 0;

        if (!info || !info->xmit_buf)
                return 0;

        save_flags(flags);
        while (1) {
                cli();          
                c = MIN(count, MIN(SERIAL_XMIT_SIZE - info->xmit_cnt - 1,
                                   SERIAL_XMIT_SIZE - info->xmit_head));
                if (c <= 0)
                        break;

                if (from_user) {
                        down(&tmp_buf_sem);
                        copy_from_user(tmp_buf, buf, c);
                        c = MIN(c, MIN(SERIAL_XMIT_SIZE - info->xmit_cnt - 1,
                                       SERIAL_XMIT_SIZE - info->xmit_head));
                        memcpy(info->xmit_buf + info->xmit_head, tmp_buf, c);
                        up(&tmp_buf_sem);
                } else
                        memcpy(info->xmit_buf + info->xmit_head, buf, c);
                info->xmit_head = (info->xmit_head + c) & (SERIAL_XMIT_SIZE-1);
                info->xmit_cnt += c;
                restore_flags(flags);
                buf += c;
                count -= c;
                total += c;
        }

        cli();          
        if (info->xmit_cnt && !tty->stopped && !tty->hw_stopped) {
                /* Enable transmitter */
                info->curregs[1] |= TxINT_ENAB|EXT_INT_ENAB;
                write_zsreg(info->zs_channel, 1, info->curregs[1]);
                info->curregs[5] |= TxENAB;
                write_zsreg(info->zs_channel, 5, info->curregs[5]);
#if 1
                zs_put_char(info->zs_channel,
                            info->xmit_buf[info->xmit_tail++]);
                info->xmit_tail = info->xmit_tail & (SERIAL_XMIT_SIZE-1);
                info->xmit_cnt--;
#endif
        }

        restore_flags(flags);
        return total;
}

static int zs_write_room(struct tty_struct *tty)
{
        struct sun_serial *info = (struct sun_serial *) tty->driver_data;
        int ret;

        if (serial_paranoia_check(info, tty->device, "zs_write_room"))
                return 0;
        ret = SERIAL_XMIT_SIZE - info->xmit_cnt - 1;
        if (ret < 0)
                ret = 0;
        return ret;
}

static int zs_chars_in_buffer(struct tty_struct *tty)
{
        struct sun_serial *info = (struct sun_serial *) tty->driver_data;

        if (serial_paranoia_check(info, tty->device, "zs_chars_in_buffer"))
                return 0;
        return info->xmit_cnt;
}

static void zs_flush_buffer(struct tty_struct *tty)
{
        struct sun_serial *info = (struct sun_serial *) tty->driver_data;

        if (serial_paranoia_check(info, tty->device, "zs_flush_buffer"))
                return;
        cli();
        info->xmit_cnt = info->xmit_head = info->xmit_tail = 0;
        sti();
        wake_up_interruptible(&tty->write_wait);
        if ((tty->flags & (1 << TTY_DO_WRITE_WAKEUP)) &&
            tty->ldisc.write_wakeup)
                (tty->ldisc.write_wakeup)(tty);
}

/*
 * ------------------------------------------------------------
 * zs_throttle()
 * 
 * This routine is called by the upper-layer tty layer to signal that
 * incoming characters should be throttled.
 * ------------------------------------------------------------
 */
static void zs_throttle(struct tty_struct * tty)
{
        struct sun_serial *info = (struct sun_serial *) tty->driver_data;
#ifdef SERIAL_DEBUG_THROTTLE
        char    buf[64];
        
        printk("throttle %s: %d....\n", _tty_name(tty, buf),
               tty->ldisc.chars_in_buffer(tty));
#endif

        if (serial_paranoia_check(info, tty->device, "zs_throttle"))
                return;
        
        if (I_IXOFF(tty))
                info->x_char = STOP_CHAR(tty);

        /* Turn off RTS line */
        cli();
        info->curregs[5] &= ~RTS;
        write_zsreg(info->zs_channel, 5, info->curregs[5]);
        sti();
}

static void zs_unthrottle(struct tty_struct * tty)
{
        struct sun_serial *info = (struct sun_serial *) tty->driver_data;
#ifdef SERIAL_DEBUG_THROTTLE
        char    buf[64];
        
        printk("unthrottle %s: %d....\n", _tty_name(tty, buf),
               tty->ldisc.chars_in_buffer(tty));
#endif

        if (serial_paranoia_check(info, tty->device, "zs_unthrottle"))
                return;
        
        if (I_IXOFF(tty)) {
                if (info->x_char)
                        info->x_char = 0;
                else
                        info->x_char = START_CHAR(tty);
        }

        /* Assert RTS line */
        cli();
        info->curregs[5] |= RTS;
        write_zsreg(info->zs_channel, 5, info->curregs[5]);
        sti();
}

/*
 * ------------------------------------------------------------
 * zs_ioctl() and friends
 * ------------------------------------------------------------
 */

static int get_serial_info(struct sun_serial * info,
                           struct serial_struct * retinfo)
{
        struct serial_struct tmp;
  
        if (!retinfo)
                return -EFAULT;
        memset(&tmp, 0, sizeof(tmp));
        tmp.type = info->type;
        tmp.line = info->line;
        tmp.port = info->port;
        tmp.irq = info->irq;
        tmp.flags = info->flags;
        tmp.baud_base = info->baud_base;
        tmp.close_delay = info->close_delay;
        tmp.closing_wait = info->closing_wait;
        tmp.custom_divisor = info->custom_divisor;
        if (copy_to_user(retinfo,&tmp,sizeof(*retinfo)))
                return -EFAULT;
        return 0;
}

static int set_serial_info(struct sun_serial * info,
                           struct serial_struct * new_info)
{
        struct serial_struct new_serial;
        struct sun_serial old_info;
        int retval = 0;

        if (!new_info || copy_from_user(&new_serial,new_info,sizeof(new_serial)))
                return -EFAULT;
        old_info = *info;

        if (!capable(CAP_SYS_ADMIN)) {
                if ((new_serial.baud_base != info->baud_base) ||
                    (new_serial.type != info->type) ||
                    (new_serial.close_delay != info->close_delay) ||
                    ((new_serial.flags & ~ZILOG_USR_MASK) !=
                     (info->flags & ~ZILOG_USR_MASK)))
                        return -EPERM;
                info->flags = ((info->flags & ~ZILOG_USR_MASK) |
                               (new_serial.flags & ZILOG_USR_MASK));
                info->custom_divisor = new_serial.custom_divisor;
                goto check_and_exit;
        }

        if(new_serial.baud_base < 9600)
                return -EINVAL;

        if (info->count > 1)
                return -EBUSY;

        /*
         * OK, past this point, all the error checking has been done.
         * At this point, we start making changes.....
         */

        info->baud_base = new_serial.baud_base;
        info->flags = ((info->flags & ~ZILOG_FLAGS) |
                        (new_serial.flags & ZILOG_FLAGS));
        info->custom_divisor = new_serial.custom_divisor;
        info->type = new_serial.type;
        info->close_delay = new_serial.close_delay;
        info->closing_wait = new_serial.closing_wait;

check_and_exit:
        retval = startup(info);
        return retval;
}

/*
 * get_lsr_info - get line status register info
 *
 * Purpose: Let user call ioctl() to get info when the UART physically
 *          is emptied.  On bus types like RS485, the transmitter must
 *          release the bus after transmitting. This must be done when
 *          the transmit shift register is empty, not be done when the
 *          transmit holding register is empty.  This functionality
 *          allows an RS485 driver to be written in user space. 
 */
static int get_lsr_info(struct sun_serial * info, unsigned int *value)
{
        unsigned char status;

        cli();
        status = sbus_readb(&info->zs_channel->control);
        ZSDELAY();
        ZSLOG(REGCTRL, status, 0);
        sti();
        if (put_user(status, value))
                return -EFAULT;
        return 0;
}

static int get_modem_info(struct sun_serial * info, unsigned int *value)
{
        unsigned char status;
        unsigned int result;

        cli();
        status = sbus_readb(&info->zs_channel->control);
        ZSDELAY();
        ZSLOG(REGCTRL, status, 0);
        sti();
        result =  ((info->curregs[5] & RTS) ? TIOCM_RTS : 0)
                | ((info->curregs[5] & DTR) ? TIOCM_DTR : 0)
                | ((status  & DCD) ? TIOCM_CAR : 0)
                | ((status  & SYNC) ? TIOCM_DSR : 0)
                | ((status  & CTS) ? TIOCM_CTS : 0);
        if (put_user(result, value))
                return -EFAULT;
        return 0;
}

static int set_modem_info(struct sun_serial * info, unsigned int cmd,
                          unsigned int *value)
{
        unsigned int arg;

        if (get_user(arg, value))
                return -EFAULT;
        switch (cmd) {
        case TIOCMBIS: 
                if (arg & TIOCM_RTS)
                        info->curregs[5] |= RTS;
                if (arg & TIOCM_DTR)
                        info->curregs[5] |= DTR;
                break;
        case TIOCMBIC:
                if (arg & TIOCM_RTS)
                        info->curregs[5] &= ~RTS;
                if (arg & TIOCM_DTR)
                        info->curregs[5] &= ~DTR;
                break;
        case TIOCMSET:
                info->curregs[5] = ((info->curregs[5] & ~(RTS | DTR))
                             | ((arg & TIOCM_RTS) ? RTS : 0)
                             | ((arg & TIOCM_DTR) ? DTR : 0));
                break;
        default:
                return -EINVAL;
        }
        cli();
        write_zsreg(info->zs_channel, 5, info->curregs[5]);
        sti();
        return 0;
}

/*
 * This routine sends a break character out the serial port.
 */
static void send_break( struct sun_serial * info, int duration)
{
        if (!info->port)
                return;
        current->state = TASK_INTERRUPTIBLE;
        cli();
        write_zsreg(info->zs_channel, 5, (info->curregs[5] | SND_BRK));
        schedule_timeout(duration);
        write_zsreg(info->zs_channel, 5, info->curregs[5]);
        sti();
}

static int zs_ioctl(struct tty_struct *tty, struct file * file,
                    unsigned int cmd, unsigned long arg)
{
        struct sun_serial * info = (struct sun_serial *) tty->driver_data;
        int retval;

        if (serial_paranoia_check(info, tty->device, "zs_ioctl"))
                return -ENODEV;

        if ((cmd != TIOCGSERIAL) && (cmd != TIOCSSERIAL) &&
            (cmd != TIOCSERCONFIG) && (cmd != TIOCSERGWILD)  &&
            (cmd != TIOCSERSWILD) && (cmd != TIOCSERGSTRUCT)) {
                if (tty->flags & (1 << TTY_IO_ERROR))
                    return -EIO;
        }
        
        switch (cmd) {
                case TCSBRK:    /* SVID version: non-zero arg --> no break */
                        retval = tty_check_change(tty);
                        if (retval)
                                return retval;
                        tty_wait_until_sent(tty, 0);
                        if (!arg)
                                send_break(info, HZ/4); /* 1/4 second */
                        return 0;
                case TCSBRKP:   /* support for POSIX tcsendbreak() */
                        retval = tty_check_change(tty);
                        if (retval)
                                return retval;
                        tty_wait_until_sent(tty, 0);
                        send_break(info, arg ? arg*(HZ/10) : HZ/4);
                        return 0;
                case TIOCGSOFTCAR:
                        if (put_user(C_CLOCAL(tty) ? 1 : 0,
                                     (unsigned long *) arg))
                                return -EFAULT;
                        return 0;
                case TIOCSSOFTCAR:
                        if (get_user(arg, (unsigned long *) arg))
                                return -EFAULT;
                        tty->termios->c_cflag =
                                ((tty->termios->c_cflag & ~CLOCAL) |
                                 (arg ? CLOCAL : 0));
                        return 0;
                case TIOCMGET:
                        return get_modem_info(info, (unsigned int *) arg);
                case TIOCMBIS:
                case TIOCMBIC:
                case TIOCMSET:
                        return set_modem_info(info, cmd, (unsigned int *) arg);
                case TIOCGSERIAL:
                        return get_serial_info(info,
                                               (struct serial_struct *) arg);
                case TIOCSSERIAL:
                        return set_serial_info(info,
                                               (struct serial_struct *) arg);
                case TIOCSERGETLSR: /* Get line status register */
                        return get_lsr_info(info, (unsigned int *) arg);

                case TIOCSERGSTRUCT:
                        if (copy_to_user((struct sun_serial *) arg,
                                    info, sizeof(struct sun_serial)))
                                return -EFAULT;
                        return 0;
                        
                default:
                        return -ENOIOCTLCMD;
                }
        return 0;
}

static void zs_set_termios(struct tty_struct *tty, struct termios *old_termios)
{
        struct sun_serial *info = (struct sun_serial *) tty->driver_data;

        if (tty->termios->c_cflag == old_termios->c_cflag)
                return;

        change_speed(info);

        if ((old_termios->c_cflag & CRTSCTS) &&
            !(tty->termios->c_cflag & CRTSCTS)) {
                tty->hw_stopped = 0;
                zs_start(tty);
        }
}

/*
 * ------------------------------------------------------------
 * zs_close()
 * 
 * This routine is called when the serial port gets closed.  First, we
 * wait for the last remaining data to be sent.  Then, we unlink its
 * ZILOG structure from the interrupt chain if necessary, and we free
 * that IRQ if nothing is left in the chain.
 * ------------------------------------------------------------
 */
static void zs_close(struct tty_struct *tty, struct file * filp)
{
        struct sun_serial * info = (struct sun_serial *) tty->driver_data;
        unsigned long flags;

        if (!info || serial_paranoia_check(info, tty->device, "zs_close"))
                return;
        
        save_flags(flags); cli();
        
        if (tty_hung_up_p(filp)) {
                restore_flags(flags);
                return;
        }
        
#ifdef SERIAL_DEBUG_OPEN
        printk("zs_close tty-%d, count = %d\n", info->line, info->count);
#endif
        if ((tty->count == 1) && (info->count != 1)) {
                /*
                 * Uh, oh.  tty->count is 1, which means that the tty
                 * structure will be freed.  Info->count should always
                 * be one in these conditions.  If it's greater than
                 * one, we've got real problems, since it means the
                 * serial port won't be shutdown.
                 */
                printk("zs_close: bad serial port count; tty->count is 1, "
                       "info->count is %d\n", info->count);
                info->count = 1;
        }
        if (--info->count < 0) {
                printk("zs_close: bad serial port count for ttys%d: %d\n",
                       info->line, info->count);
                info->count = 0;
        }
        if (info->count) {
                restore_flags(flags);
                return;
        }
        info->flags |= ZILOG_CLOSING;
        /*
         * Save the termios structure, since this port may have
         * separate termios for callout and dialin.
         */
        if (info->flags & ZILOG_NORMAL_ACTIVE)
                info->normal_termios = *tty->termios;
        if (info->flags & ZILOG_CALLOUT_ACTIVE)
                info->callout_termios = *tty->termios;
        /*
         * Now we wait for the transmit buffer to clear; and we notify 
         * the line discipline to only process XON/XOFF characters.
         */
        tty->closing = 1;
        if (info->closing_wait != ZILOG_CLOSING_WAIT_NONE)
                tty_wait_until_sent(tty, info->closing_wait);
        /*
         * At this point we stop accepting input.  To do this, we
         * disable the receive line status interrupts, and tell the
         * interrupt driver to stop checking the data ready bit in the
         * line status register.
         */
        /** if (!info->iscons) ... **/
        info->curregs[3] &= ~RxENAB;
        write_zsreg(info->zs_channel, 3, info->curregs[3]);
        info->curregs[1] &= ~(RxINT_MASK);
        write_zsreg(info->zs_channel, 1, info->curregs[1]);
        ZS_CLEARFIFO(info->zs_channel);

        shutdown(info);
        if (tty->driver.flush_buffer)
                tty->driver.flush_buffer(tty);
        if (tty->ldisc.flush_buffer)
                tty->ldisc.flush_buffer(tty);
        tty->closing = 0;
        info->event = 0;
        info->tty = 0;
        if (tty->ldisc.num != ldiscs[N_TTY].num) {
                if (tty->ldisc.close)
                        (tty->ldisc.close)(tty);
                tty->ldisc = ldiscs[N_TTY];
                tty->termios->c_line = N_TTY;
                if (tty->ldisc.open)
                        (tty->ldisc.open)(tty);
        }
        if (info->blocked_open) {
                if (info->close_delay) {
                        current->state = TASK_INTERRUPTIBLE;
                        schedule_timeout(info->close_delay);
                }
                wake_up_interruptible(&info->open_wait);
        }
        info->flags &= ~(ZILOG_NORMAL_ACTIVE|ZILOG_CALLOUT_ACTIVE|
                         ZILOG_CLOSING);
        wake_up_interruptible(&info->close_wait);
#ifdef SERIAL_DEBUG_OPEN
        printk("zs_close tty-%d exiting, count = %d\n", info->line, info->count);
#endif
        restore_flags(flags);
}

/*
 * zs_hangup() --- called by tty_hangup() when a hangup is signaled.
 */
void zs_hangup(struct tty_struct *tty)
{
        struct sun_serial * info = (struct sun_serial *) tty->driver_data;

        if (serial_paranoia_check(info, tty->device, "zs_hangup"))
                return;

        if (info->is_cons)
                return;

#ifdef SERIAL_DEBUG_OPEN
        printk("zs_hangup<%p: tty-%d, count = %d bye\n",
                __builtin_return_address(0), info->line, info->count);
#endif

        zs_flush_buffer(tty);
        shutdown(info);
        info->event = 0;
        info->count = 0;
        info->flags &= ~(ZILOG_NORMAL_ACTIVE|ZILOG_CALLOUT_ACTIVE);
        info->tty = 0;
        wake_up_interruptible(&info->open_wait);
}

/*
 * ------------------------------------------------------------
 * zs_open() and friends
 * ------------------------------------------------------------
 */
static int block_til_ready(struct tty_struct *tty, struct file * filp,
                           struct sun_serial *info)
{
        DECLARE_WAITQUEUE(wait, current);
        int retval, do_clocal = 0;
        unsigned char r0;

        /*
         * If the device is in the middle of being closed, then block
         * until it's done, and then try again.
         */
        if (info->flags & ZILOG_CLOSING) {
                interruptible_sleep_on(&info->close_wait);
#ifdef SERIAL_DO_RESTART
                if (info->flags & ZILOG_HUP_NOTIFY)
                        return -EAGAIN;
                else
                        return -ERESTARTSYS;
#else
                return -EAGAIN;
#endif
        }

        /*
         * If this is a callout device, then just make sure the normal
         * device isn't being used.
         */
        if (tty->driver.subtype == SERIAL_TYPE_CALLOUT) {
                if (info->flags & ZILOG_NORMAL_ACTIVE)
                        return -EBUSY;
                if ((info->flags & ZILOG_CALLOUT_ACTIVE) &&
                    (info->flags & ZILOG_SESSION_LOCKOUT) &&
                    (info->session != current->session))
                    return -EBUSY;
                if ((info->flags & ZILOG_CALLOUT_ACTIVE) &&
                    (info->flags & ZILOG_PGRP_LOCKOUT) &&
                    (info->pgrp != current->pgrp))
                    return -EBUSY;
                info->flags |= ZILOG_CALLOUT_ACTIVE;
                return 0;
        }
        
        /*
         * If non-blocking mode is set, or the port is not enabled,
         * then make the check up front and then exit.
         */
        if ((filp->f_flags & O_NONBLOCK) ||
            (tty->flags & (1 << TTY_IO_ERROR))) {
                if (info->flags & ZILOG_CALLOUT_ACTIVE)
                        return -EBUSY;
                info->flags |= ZILOG_NORMAL_ACTIVE;
                return 0;
        }

        if (info->flags & ZILOG_CALLOUT_ACTIVE) {
                if (info->normal_termios.c_cflag & CLOCAL)
                        do_clocal = 1;
        } else {
                if (tty->termios->c_cflag & CLOCAL)
                        do_clocal = 1;
        }
        
        /*
         * Block waiting for the carrier detect and the line to become
         * free (i.e., not in use by the callout).  While we are in
         * this loop, info->count is dropped by one, so that
         * zs_close() knows when to free things.  We restore it upon
         * exit, either normal or abnormal.
         */
        retval = 0;
        add_wait_queue(&info->open_wait, &wait);
#ifdef SERIAL_DEBUG_OPEN
        printk("block_til_ready before block: ttys%d, count = %d\n",
               info->line, info->count);
#endif
        cli();
        if(!tty_hung_up_p(filp))
                info->count--;
        sti();
        info->blocked_open++;
        while (1) {
                cli();
                if (!(info->flags & ZILOG_CALLOUT_ACTIVE))
                        zs_rtsdtr(info, 1);
                sti();
                set_current_state(TASK_INTERRUPTIBLE);
                if (tty_hung_up_p(filp) ||
                    !(info->flags & ZILOG_INITIALIZED)) {
#ifdef SERIAL_DEBUG_OPEN
                        printk("block_til_ready hup-ed: ttys%d, count = %d\n",
                                info->line, info->count);
#endif
#ifdef SERIAL_DO_RESTART
                        if (info->flags & ZILOG_HUP_NOTIFY)
                                retval = -EAGAIN;
                        else
                                retval = -ERESTARTSYS;  
#else
                        retval = -EAGAIN;
#endif
                        break;
                }

                cli();
                r0 = read_zsreg(info->zs_channel, R0);
                sti();
                if (!(info->flags & ZILOG_CALLOUT_ACTIVE) &&
                    !(info->flags & ZILOG_CLOSING) &&
                    (do_clocal || (DCD & r0)))
                        break;
                if (signal_pending(current)) {
                        retval = -ERESTARTSYS;
                        break;
                }
#ifdef SERIAL_DEBUG_OPEN
                printk("block_til_ready blocking: ttys%d, count = %d\n",
                       info->line, info->count);
#endif
                schedule();
        }
        current->state = TASK_RUNNING;
        remove_wait_queue(&info->open_wait, &wait);
        if (!tty_hung_up_p(filp))
                info->count++;
        info->blocked_open--;
#ifdef SERIAL_DEBUG_OPEN
        printk("block_til_ready after blocking: ttys%d, count = %d\n",
               info->line, info->count);
#endif
        if (retval)
                return retval;
        info->flags |= ZILOG_NORMAL_ACTIVE;
        return 0;
}       

/*
 * This routine is called whenever a serial port is opened.  It
 * enables interrupts for a serial port, linking in its ZILOG structure into
 * the IRQ chain.   It also performs the serial-specific
 * initialization for the tty structure.
 */
int zs_open(struct tty_struct *tty, struct file * filp)
{
        struct sun_serial *info;
        int retval, line;

        line = MINOR(tty->device) - tty->driver.minor_start;

        /* The zilog lines for the mouse/keyboard must be
         * opened using their respective drivers.
         */
        if ((line < 0) || (line >= NUM_CHANNELS))
                return -ENODEV;
        if((line == KEYBOARD_LINE) || (line == MOUSE_LINE))
                return -ENODEV;
        info = zs_soft + line;
        /* Is the kgdb running over this line? */
        if (info->kgdb_channel)
                return -ENODEV;
        if (serial_paranoia_check(info, tty->device, "zs_open"))
                return -ENODEV;
#ifdef SERIAL_DEBUG_OPEN
        printk("zs_open %s%d, count = %d\n", tty->driver.name, info->line,
               info->count);
#endif
        if (info->tty != 0 && info->tty != tty) {
                /* Never happen? */
                printk("zs_open %s%d, tty overwrite.\n", tty->driver.name, info->line);
                return -EBUSY;
        }
        info->count++;
        tty->driver_data = info;
        info->tty = tty;

        /*
         * Start up serial port
         */
        retval = startup(info);
        if (retval)
                return retval;

        retval = block_til_ready(tty, filp, info);
        if (retval) {
#ifdef SERIAL_DEBUG_OPEN
                printk("zs_open returning after block_til_ready with %d\n",
                       retval);
#endif
                return retval;
        }

        if ((info->count == 1) && (info->flags & ZILOG_SPLIT_TERMIOS)) {
                if (tty->driver.subtype == SERIAL_TYPE_NORMAL)
                        *tty->termios = info->normal_termios;
                else 
                        *tty->termios = info->callout_termios;
                change_speed(info);
        }

#ifdef CONFIG_SERIAL_CONSOLE
        if (zs_console.cflag && zs_console.index == line) {
                tty->termios->c_cflag = zs_console.cflag;
                zs_console.cflag = 0;
                change_speed(info);
        }
#endif

        info->session = current->session;
        info->pgrp = current->pgrp;

#ifdef SERIAL_DEBUG_OPEN
        printk("zs_open ttys%d successful...", info->line);
#endif
        return 0;
}

/* Finally, routines used to initialize the serial driver. */

static void show_serial_version(void)
{
        char *revision = "$Revision: 1.60 $";
        char *version, *p;

        version = strchr(revision, ' ');
        p = strchr(++version, ' ');
        *p = '\0';
        printk("Sparc Zilog8530 serial driver version %s\n", version);
        *p = ' ';
}

/* Probe the PROM for the request zs chip number.
 *
 * Note: The Sun Voyager shows two addresses and two intr for it's
 *       Zilogs, what the second does, I don't know. It does work
 *       with using only the first number of each property.  Also
 *       we have a special version for sun4u.
 */
#ifdef __sparc_v9__
static struct sun_zslayout * __init get_zs(int chip)
{
        unsigned int vaddr[2] = { 0, 0 };
        unsigned long mapped_addr = 0;
        int busnode, seen, zsnode, sun4u_ino;
        static int irq = 0;

        if(chip < 0 || chip >= NUM_SERIAL) {
                prom_printf("get_zs bogon zs chip number");
                prom_halt();
        }

        if(central_bus)
                busnode = central_bus->child->prom_node;
        else
                busnode = prom_searchsiblings(prom_getchild(prom_root_node), "sbus");
        if(busnode == 0 || busnode == -1) {
                prom_printf("get_zs: no zs bus to search");
                prom_halt();
        }
        zsnode = prom_getchild(busnode);
        seen = 0;
        while(zsnode) {
                int slave;

                zsnode = prom_searchsiblings(zsnode, "zs");
                slave = prom_getintdefault(zsnode, "slave", -1);
                if((slave == chip) || (seen == chip)) {
                        int len = prom_getproperty(zsnode, "address",
                                                   (void *) vaddr, sizeof(vaddr));

                        if(len == -1 || central_bus != NULL) {
                                struct sbus_bus *sbus = NULL;
                                struct sbus_dev *sdev = NULL;

                                /* "address" property is not guarenteed,
                                 * everything in I/O is implicitly mapped
                                 * anyways by our clever TLB miss handling
                                 * scheme, so don't fail here.  -DaveM
                                 */
                                if (central_bus == NULL) {
                                        for_each_sbus(sbus) {
                                                for_each_sbusdev(sdev, sbus) {
                                                        if (sdev->prom_node == zsnode)
                                                                goto found;
                                                }
                                        }
                                }
                        found:
                                if (sdev == NULL && central_bus == NULL)
                                        prom_halt();
                                if (central_bus == NULL) {
                                        mapped_addr =
                                            sbus_ioremap(&sdev->resource[0], 0,
                                                         PAGE_SIZE, "Zilog Registers");
                                } else {
                                        struct linux_prom_registers zsregs[1];
                                        int err;

                                        err = prom_getproperty(zsnode, "reg",
                                                               (char *)&zsregs[0],
                                                               sizeof(zsregs));
                                        if (err == -1) {
                                                prom_printf("ZS: Cannot map Zilog regs.\n");
                                                prom_halt();
                                        }
                                        apply_fhc_ranges(central_bus->child, &zsregs[0], 1);
                                        apply_central_ranges(central_bus, &zsregs[0], 1);
                                        mapped_addr =
                                                ((((u64)zsregs[0].which_io)<<32UL)|
                                                 ((u64)zsregs[0].phys_addr));
                                }
                        } else if(len % sizeof(unsigned int)) {
                                prom_printf("WHOOPS:  proplen for %s "
                                            "was %d, need multiple of "
                                            "%d\n", "address", len,
                                            sizeof(unsigned int));
                                panic("zilog: address property");
                        }
                        zs_nodes[chip] = zsnode;
                        len = prom_getproperty(zsnode, "interrupts",
                                               (char *) &sun4u_ino,
                                               (sizeof(sun4u_ino)));
                        if(!irq) {
                                if (central_bus) {
                                        unsigned long iclr, imap;

                                        iclr = central_bus->child->fhc_regs.uregs + FHC_UREGS_ICLR;
                                        imap = central_bus->child->fhc_regs.uregs + FHC_UREGS_IMAP;
                                        irq = zilog_irq = build_irq(12, 0, iclr, imap);
                                } else {
                                        irq = zilog_irq = 
                                                sbus_build_irq(sbus_root, sun4u_ino);
                                }
                        }
                        break;
                }
                zsnode = prom_getsibling(zsnode);
                seen++;
        }
        if(!zsnode)
                panic("get_zs: whee chip not found");
        if(!vaddr[0] && !mapped_addr)
                panic("get_zs: whee no serial chip mappable");
        if (mapped_addr != 0) {
                return (struct sun_zslayout *) mapped_addr;
        } else {
                pgd_t *pgd = pgd_offset_k((unsigned long)vaddr[0]);
                pmd_t *pmd = pmd_offset(pgd, (unsigned long)vaddr[0]);
                pte_t *pte = pte_offset(pmd, (unsigned long)vaddr[0]);
                unsigned long base = pte_val(*pte) & _PAGE_PADDR;

                /* Translate PROM's mapping we captured at boot
                 * time into physical address.
                 */
                base += ((unsigned long)vaddr[0] & ~PAGE_MASK);
                return (struct sun_zslayout *) base;
        }
}
#else /* !(__sparc_v9__) */
static struct sun_zslayout * __init get_zs(int chip)
{
        struct linux_prom_irqs tmp_irq[2];
        unsigned int paddr = 0;
        unsigned int vaddr[2] = { 0, 0 };
        int zsnode, tmpnode, iospace, slave, len;
        int cpunode = 0, bbnode = 0;
        static int irq = 0;
        int chipid = chip;

        iospace = 0;
        if(chip < 0 || chip >= NUM_SERIAL)
                panic("get_zs bogon zs chip number");

        if(sparc_cpu_model == sun4) {
                struct resource dummy_resource;

                /* Grrr, these have to be hardcoded aieee */
                switch(chip) {
                case 0:
                        paddr = 0xf1000000;
                        break;
                case 1:
                        paddr = 0xf0000000;
                        break;
                };
                iospace = 0;
                zs_nodes[chip] = 0;
                if(!irq)
                        zilog_irq = irq = 12;
                dummy_resource.start = paddr;
                dummy_resource.end = paddr + 8 - 1;
                dummy_resource.flags = IORESOURCE_IO;
                vaddr[0] = sbus_ioremap(&dummy_resource, 0,
                                        8, "Zilog Serial");
        } else {
                /* Can use the prom for other machine types */
                zsnode = prom_getchild(prom_root_node);
                if (sparc_cpu_model == sun4d) {
                        int no = 0;

                        tmpnode = zsnode;
                        zsnode = 0;
                        bbnode = 0;
                        while (tmpnode && (tmpnode = prom_searchsiblings(tmpnode, "cpu-unit"))) {
                                bbnode = prom_getchild(tmpnode);
                                if (bbnode && (bbnode = prom_searchsiblings(bbnode, "bootbus"))) {
                                        if (no == (chip >> 1)) {
                                                cpunode = tmpnode;
                                                zsnode = prom_getchild(bbnode);
                                                chipid = (chip & 1);
                                                break;
                                        }
                                        no++;
                                }
                                tmpnode = prom_getsibling(tmpnode);
                        }
                        if (!tmpnode)
                                panic ("get_zs: couldn't find %dth bootbus\n", chip >> 1);
                } else {
                        tmpnode = prom_searchsiblings(zsnode, "obio");
                        if(tmpnode)
                                zsnode = prom_getchild(tmpnode);
                }
                if(!zsnode)
                        panic("get_zs no zs serial prom node");
                while(zsnode) {
                        zsnode = prom_searchsiblings(zsnode, "zs");
                        slave = prom_getintdefault(zsnode, "slave", -1);
                        if(slave == chipid) {
                                /* The one we want */
                                if (sparc_cpu_model != sun4d) {
                                        len = prom_getproperty(zsnode, "address",
                                                               (void *) vaddr,
                                                               sizeof(vaddr));
                                        if (len % sizeof(unsigned int)) {
                                                prom_printf("WHOOPS:  proplen for %s "
                                                        "was %d, need multiple of "
                                                        "%d\n", "address", len,
                                                        sizeof(unsigned int));
                                                panic("zilog: address property");
                                        }
                                } else {
                                        /* On sun4d don't have address property :( */
                                        struct linux_prom_registers zsreg[4];
                                        struct resource res;
                                        
                                        if (prom_getproperty(zsnode, "reg", (char *)zsreg, sizeof(zsreg)) == -1) {
                                                prom_printf ("Cannot map zs regs\n");
                                                prom_halt();
                                        }
                                        prom_apply_generic_ranges(bbnode, cpunode, zsreg, 1);
                                        res.start = zsreg[0].phys_addr;
                                        res.end = res.start + 8 - 1;
                                        res.flags = zsreg[0].which_io | IORESOURCE_IO;
                                        vaddr[0] = sbus_ioremap(&res, 0,
                                                                8, "Zilog Serial");
                                }
                                zs_nodes[chip] = zsnode;
                                len = prom_getproperty(zsnode, "intr",
                                                       (char *) tmp_irq,
                                                       sizeof(tmp_irq));
                                if (len % sizeof(struct linux_prom_irqs)) {
                                        prom_printf(
                                              "WHOOPS:  proplen for %s "
                                              "was %d, need multiple of "
                                              "%d\n", "intr", len,
                                              sizeof(struct linux_prom_irqs));
                                        panic("zilog: intr property");
                                }
                                if(!irq) {
                                        irq = zilog_irq = tmp_irq[0].pri;
                                } else {
                                        if(tmp_irq[0].pri != irq)
                                                panic("zilog: bogon irqs");
                                }
                                break;
                        }
                        zsnode = prom_getsibling(zsnode);
                }
                if(!zsnode)
                        panic("get_zs whee chip not found");
        }
        if(!vaddr[0])
                panic("get_zs whee no serial chip mappable");

        return (struct sun_zslayout *)(unsigned long) vaddr[0];
}
#endif
/* This is for the auto baud rate detection in the mouse driver. */
void zs_change_mouse_baud(int newbaud)
{
        int channel = MOUSE_LINE;
        int brg;

        zs_soft[channel].zs_baud = newbaud;
        brg = BPS_TO_BRG(zs_soft[channel].zs_baud,
                         (ZS_CLOCK / zs_soft[channel].clk_divisor));
        write_zsreg(zs_soft[channel].zs_channel, R12, (brg & 0xff));
        write_zsreg(zs_soft[channel].zs_channel, R13, ((brg >> 8) & 0xff));
}

void __init zs_init_alloc_failure(const char *table_name)
{
        prom_printf("zs_probe: Cannot alloc %s.\n", table_name);
        prom_halt();
}

void * __init zs_alloc_bootmem(unsigned long size)
{
        void *ret;

        ret = __alloc_bootmem(size, SMP_CACHE_BYTES, 0UL);
        if (ret != NULL)
                memset(ret, 0, size);

        return ret;
}

void __init zs_alloc_tables(void)
{
        zs_chips = (struct sun_zslayout **)
                zs_alloc_bootmem(NUM_SERIAL * sizeof(struct sun_zslayout *));
        if (zs_chips == NULL)
                zs_init_alloc_failure("zs_chips");
        zs_channels = (struct sun_zschannel **)
                zs_alloc_bootmem(NUM_CHANNELS * sizeof(struct sun_zschannel *));
        if (zs_channels == NULL)
                zs_init_alloc_failure("zs_channels");
        zs_nodes = (int *)
                zs_alloc_bootmem(NUM_SERIAL * sizeof(int));
        if (zs_nodes == NULL)
                zs_init_alloc_failure("zs_nodes");
        zs_soft = (struct sun_serial *)
                zs_alloc_bootmem(NUM_CHANNELS * sizeof(struct sun_serial));
        if (zs_soft == NULL)
                zs_init_alloc_failure("zs_soft");
        zs_ttys = (struct tty_struct *)
                zs_alloc_bootmem(NUM_CHANNELS * sizeof(struct tty_struct));
        if (zs_ttys == NULL)
                zs_init_alloc_failure("zs_ttys");
        serial_table = (struct tty_struct **)
                zs_alloc_bootmem(NUM_CHANNELS * sizeof(struct tty_struct *));
        if (serial_table == NULL)
                zs_init_alloc_failure("serial_table");
        serial_termios = (struct termios **)
                zs_alloc_bootmem(NUM_CHANNELS * sizeof(struct termios *));
        if (serial_termios == NULL)
                zs_init_alloc_failure("serial_termios");
        serial_termios_locked = (struct termios **)
                zs_alloc_bootmem(NUM_CHANNELS * sizeof(struct termios *));
        if (serial_termios_locked == NULL)
                zs_init_alloc_failure("serial_termios_locked");
}

int __init zs_probe(void)
{
        int node;

        if(sparc_cpu_model == sun4)
                goto no_probe;

        NUM_SERIAL = 0;
        
        node = prom_getchild(prom_root_node);
        if (sparc_cpu_model == sun4d) {
                int bbnode;
                
                while (node && (node = prom_searchsiblings(node, "cpu-unit"))) {
                        bbnode = prom_getchild(node);
                        if (bbnode && prom_searchsiblings(bbnode, "bootbus"))
                                NUM_SERIAL += 2;
                        node = prom_getsibling(node);
                }
                goto no_probe;
        }
#ifdef __sparc_v9__
        else if (sparc_cpu_model == sun4u) {
                int central_node;

                /* Central bus zilogs must be checked for first,
                 * since Enterprise boxes might have SBUSes as well.
                 */
                central_node = prom_finddevice("/central");
                if(central_node != 0 && central_node != -1)
                        node = prom_searchsiblings(prom_getchild(central_node), "fhc");
                else
                        node = prom_searchsiblings(node, "sbus");
                if(node != 0 && node != -1)
                        node = prom_getchild(node);
                if(node == 0 || node == -1)
                        return -ENODEV;
        }
#endif /* __sparc_v9__ */
        else {
                node = prom_searchsiblings(node, "obio");
                if(node)
                        node = prom_getchild(node);
                NUM_SERIAL = 2;
                goto no_probe;
        }

        node = prom_searchsiblings(node, "zs");
        if (!node)
                return -ENODEV;
                
        NUM_SERIAL = 2;

no_probe:
        zs_alloc_tables();

        /* Fill in rs_ops struct... */
#ifdef CONFIG_SERIAL_CONSOLE
        sunserial_setinitfunc(zs_console_init);
#endif
        sunserial_setinitfunc(zs_init);
        rs_ops.rs_kgdb_hook = zs_kgdb_hook;
        rs_ops.rs_change_mouse_baud = zs_change_mouse_baud;

        sunkbd_setinitfunc(sun_kbd_init);
        kbd_ops.compute_shiftstate = sun_compute_shiftstate;
        kbd_ops.setledstate = sun_setledstate;
        kbd_ops.getledstate = sun_getledstate;
        kbd_ops.setkeycode = sun_setkeycode;
        kbd_ops.getkeycode = sun_getkeycode;
#if defined(__sparc_v9__) && defined(CONFIG_PCI)
        sunkbd_install_keymaps(sun_key_maps, sun_keymap_count,
                               sun_func_buf, sun_func_table,
                               sun_funcbufsize, sun_funcbufleft,
                               sun_accent_table, sun_accent_table_size);
#endif
        return 0;
}

static inline void zs_prepare(void)
{
        int channel, chip;
        unsigned long flags;

        if (!NUM_SERIAL)
                return;
        
        save_and_cli(flags);
        
        /* Set up our interrupt linked list */
        zs_chain = &zs_soft[0];
        for(channel = 0; channel < NUM_CHANNELS - 1; channel++) {
                zs_soft[channel].zs_next = &zs_soft[channel + 1];
                zs_soft[channel].line = channel;
        }
        zs_soft[channel].zs_next = 0;

        /* Initialize Softinfo */
        for(chip = 0; chip < NUM_SERIAL; chip++) {
                /* If we are doing kgdb over one of the channels on
                 * chip zero, kgdb_channel will be set to 1 by the
                 * zs_kgdb_hook() routine below.
                 */
                if(!zs_chips[chip]) {
                        zs_chips[chip] = get_zs(chip);
                        /* Two channels per chip */
                        zs_channels[(chip*2)] = &zs_chips[chip]->channelA;
                        zs_channels[(chip*2)+1] = &zs_chips[chip]->channelB;
                        zs_soft[(chip*2)].kgdb_channel = 0;
                        zs_soft[(chip*2)+1].kgdb_channel = 0;
                }

                /* First, set up channel A on this chip. */
                channel = chip * 2;
                zs_soft[channel].zs_channel = zs_channels[channel];
                zs_soft[channel].change_needed = 0;
                zs_soft[channel].clk_divisor = 16;
                zs_soft[channel].cons_keyb = 0;
                zs_soft[channel].cons_mouse = 0;
                zs_soft[channel].channelA = 1;

                /* Now, channel B */
                channel++;
                zs_soft[channel].zs_channel = zs_channels[channel];
                zs_soft[channel].change_needed = 0;
                zs_soft[channel].clk_divisor = 16;
                zs_soft[channel].cons_keyb = 0;
                zs_soft[channel].cons_mouse = 0;
                zs_soft[channel].channelA = 0;
        }
        
        restore_flags(flags);
}

int __init zs_init(void)
{
        int channel, brg, i;
        unsigned long flags;
        struct sun_serial *info;
        char dummy;

        /* Setup base handler, and timer table. */
        init_bh(SERIAL_BH, do_serial_bh);

        show_serial_version();

        /* Initialize the tty_driver structure */
        /* SPARC: Not all of this is exactly right for us. */
        
        memset(&serial_driver, 0, sizeof(struct tty_driver));
        serial_driver.magic = TTY_DRIVER_MAGIC;
        serial_driver.driver_name = "serial";
#ifdef CONFIG_DEVFS_FS
        serial_driver.name = "tts/%d";
#else
        serial_driver.name = "ttyS";
#endif
        serial_driver.major = TTY_MAJOR;
        serial_driver.minor_start = 64;
        serial_driver.num = NUM_CHANNELS;
        serial_driver.type = TTY_DRIVER_TYPE_SERIAL;
        serial_driver.subtype = SERIAL_TYPE_NORMAL;
        serial_driver.init_termios = tty_std_termios;
        serial_driver.init_termios.c_cflag =
                B9600 | CS8 | CREAD | HUPCL | CLOCAL;
        serial_driver.flags = TTY_DRIVER_REAL_RAW;
        serial_driver.refcount = &serial_refcount;
        serial_driver.table = serial_table;
        serial_driver.termios = serial_termios;
        serial_driver.termios_locked = serial_termios_locked;

        serial_driver.open = zs_open;
        serial_driver.close = zs_close;
        serial_driver.write = zs_write;
        serial_driver.flush_chars = zs_flush_chars;
        serial_driver.write_room = zs_write_room;
        serial_driver.chars_in_buffer = zs_chars_in_buffer;
        serial_driver.flush_buffer = zs_flush_buffer;
        serial_driver.ioctl = zs_ioctl;
        serial_driver.throttle = zs_throttle;
        serial_driver.unthrottle = zs_unthrottle;
        serial_driver.set_termios = zs_set_termios;
        serial_driver.stop = zs_stop;
        serial_driver.start = zs_start;
        serial_driver.hangup = zs_hangup;

        /* I'm too lazy, someone write versions of this for us. -DaveM */
        serial_driver.read_proc = 0;
        serial_driver.proc_entry = 0;

        /*
         * The callout device is just like normal device except for
         * major number and the subtype code.
         */
        callout_driver = serial_driver;
        callout_driver.name = "cua/%d";
        callout_driver.major = TTYAUX_MAJOR;
        callout_driver.subtype = SERIAL_TYPE_CALLOUT;

        if (tty_register_driver(&serial_driver))
                panic("Couldn't register serial driver\n");
        if (tty_register_driver(&callout_driver))
                panic("Couldn't register callout driver\n");

        save_flags(flags); cli();

        /* Initialize Softinfo */
        zs_prepare();

        /* Grab IRQ line before poking the chips so we do
         * not lose any interrupts.
         */
        if (request_irq(zilog_irq, zs_interrupt,
                        (SA_INTERRUPT | SA_STATIC_ALLOC),
                        "Zilog8530", zs_chain)) {
                prom_printf("Unable to attach zs intr\n");
                prom_halt();
        }

        /* Initialize Hardware */
        for(channel = 0; channel < NUM_CHANNELS; channel++) {
                /* Hardware reset each chip */
                if (!(channel & 1)) {
                        write_zsreg(zs_soft[channel].zs_channel, R9, FHWRES);
                        ZSDELAY_LONG();
                        dummy = read_zsreg(zs_soft[channel].zs_channel, R0);
                }

                if(channel == KEYBOARD_LINE) {
                        zs_soft[channel].cons_keyb = 1;
                        zs_soft[channel].parity_mask = 0xff;
                        zs_kbdchan = zs_soft[channel].zs_channel;

                        write_zsreg(zs_soft[channel].zs_channel, R4,
                                    (PAR_EVEN | X16CLK | SB1));
                        write_zsreg(zs_soft[channel].zs_channel, R3, Rx8);
                        write_zsreg(zs_soft[channel].zs_channel, R5, Tx8);
                        write_zsreg(zs_soft[channel].zs_channel, R9, NV);
                        write_zsreg(zs_soft[channel].zs_channel, R10, NRZ);
                        write_zsreg(zs_soft[channel].zs_channel, R11,
                                    (TCBR | RCBR));
                        zs_soft[channel].zs_baud = 1200;
                        brg = BPS_TO_BRG(zs_soft[channel].zs_baud,
                                         ZS_CLOCK/zs_soft[channel].clk_divisor);
                        write_zsreg(zs_soft[channel].zs_channel, R12,
                                    (brg & 0xff));
                        write_zsreg(zs_soft[channel].zs_channel, R13,
                                    ((brg >> 8) & 0xff));
                        write_zsreg(zs_soft[channel].zs_channel, R14, BRSRC);

                        /* Enable Rx/Tx, IRQs, and inform kbd driver */
                        write_zsreg(zs_soft[channel].zs_channel, R14,
                                    (BRSRC | BRENAB));
                        write_zsreg(zs_soft[channel].zs_channel, R3,
                                    (Rx8 | RxENAB));
                        write_zsreg(zs_soft[channel].zs_channel, R5,
                                    (Tx8 | TxENAB | DTR | RTS));

                        write_zsreg(zs_soft[channel].zs_channel, R15,
                                    (DCDIE | CTSIE | TxUIE | BRKIE));
                        write_zsreg(zs_soft[channel].zs_channel, R0,
                                    RES_EXT_INT);
                        write_zsreg(zs_soft[channel].zs_channel, R0,
                                    RES_EXT_INT);

                        write_zsreg(zs_soft[channel].zs_channel, R1,
                                    (EXT_INT_ENAB | INT_ALL_Rx));
                        write_zsreg(zs_soft[channel].zs_channel, R9,
                                    (NV | MIE));
                        ZS_CLEARERR(zs_soft[channel].zs_channel);
                        ZS_CLEARFIFO(zs_soft[channel].zs_channel);
                } else if(channel == MOUSE_LINE) {
                        zs_soft[channel].cons_mouse = 1;
                        zs_soft[channel].parity_mask = 0xff;
                        zs_mousechan = zs_soft[channel].zs_channel;

                        write_zsreg(zs_soft[channel].zs_channel, R4,
                                    (PAR_EVEN | X16CLK | SB1));
                        write_zsreg(zs_soft[channel].zs_channel, R3, Rx8);
                        write_zsreg(zs_soft[channel].zs_channel, R5, Tx8);
                        write_zsreg(zs_soft[channel].zs_channel, R9, NV);
                        write_zsreg(zs_soft[channel].zs_channel, R10, NRZ);
                        write_zsreg(zs_soft[channel].zs_channel, R11,
                                    (TCBR | RCBR));

                        zs_soft[channel].zs_baud = 4800;
                        brg = BPS_TO_BRG(zs_soft[channel].zs_baud,
                                         ZS_CLOCK/zs_soft[channel].clk_divisor);
                        write_zsreg(zs_soft[channel].zs_channel, R12,
                                    (brg & 0xff));
                        write_zsreg(zs_soft[channel].zs_channel, R13,
                                    ((brg >> 8) & 0xff));
                        write_zsreg(zs_soft[channel].zs_channel, R14, BRSRC);

                        /* Enable Rx, IRQs, and inform mouse driver */
                        write_zsreg(zs_soft[channel].zs_channel, R14,
                                    (BRSRC | BRENAB));
                        write_zsreg(zs_soft[channel].zs_channel, R3,
                                    (Rx8 | RxENAB));
                        write_zsreg(zs_soft[channel].zs_channel, R5, Tx8);

                        write_zsreg(zs_soft[channel].zs_channel, R15,
                                    (DCDIE | CTSIE | TxUIE | BRKIE));
                        write_zsreg(zs_soft[channel].zs_channel, R0,
                                    RES_EXT_INT);
                        write_zsreg(zs_soft[channel].zs_channel, R0,
                                    RES_EXT_INT);

                        write_zsreg(zs_soft[channel].zs_channel, R1,
                                    (EXT_INT_ENAB | INT_ALL_Rx));
                        write_zsreg(zs_soft[channel].zs_channel, R9,
                                    (NV | MIE));

                        sun_mouse_zsinit();
                } else if (zs_soft[channel].is_cons) {
                        brg = BPS_TO_BRG(zs_soft[channel].zs_baud,
                                         ZS_CLOCK/zs_soft[channel].clk_divisor);
                        zscons_regs[12] = brg & 0xff;
                        zscons_regs[13] = (brg >> 8) & 0xff;

                        memcpy(zs_soft[channel].curregs, zscons_regs, sizeof(zscons_regs));
                        load_zsregs(&zs_soft[channel], zscons_regs);

                        ZS_CLEARERR(zs_soft[channel].zs_channel);
                        ZS_CLEARFIFO(zs_soft[channel].zs_channel);
                } else if (zs_soft[channel].kgdb_channel) {
                        /* If this is the kgdb line, enable interrupts because
                         * we now want to receive the 'control-c' character
                         * from the client attached to us asynchronously.
                         */
                        zs_soft[channel].parity_mask = 0xff;
                        kgdb_chaninit(&zs_soft[channel], 1,
                                      zs_soft[channel].zs_baud);
                } else {
                        zs_soft[channel].parity_mask = 0xff;
                        write_zsreg(zs_soft[channel].zs_channel, R4,
                                    (PAR_EVEN | X16CLK | SB1));
                        write_zsreg(zs_soft[channel].zs_channel, R3, Rx8);
                        write_zsreg(zs_soft[channel].zs_channel, R5, Tx8);
                        write_zsreg(zs_soft[channel].zs_channel, R9, NV);
                        write_zsreg(zs_soft[channel].zs_channel, R10, NRZ);
                        write_zsreg(zs_soft[channel].zs_channel, R11,
                                    (RCBR | TCBR));
                        zs_soft[channel].zs_baud = 9600;
                        brg = BPS_TO_BRG(zs_soft[channel].zs_baud,
                                         ZS_CLOCK/zs_soft[channel].clk_divisor);
                        write_zsreg(zs_soft[channel].zs_channel, R12,
                                    (brg & 0xff));
                        write_zsreg(zs_soft[channel].zs_channel, R13,
                                    ((brg >> 8) & 0xff));
                        write_zsreg(zs_soft[channel].zs_channel, R14, BRSRC);
                        write_zsreg(zs_soft[channel].zs_channel, R14,
                                    (BRSRC | BRENAB));
                        write_zsreg(zs_soft[channel].zs_channel, R3, Rx8);
                        write_zsreg(zs_soft[channel].zs_channel, R5, Tx8);
                        write_zsreg(zs_soft[channel].zs_channel, R15, DCDIE);
                        write_zsreg(zs_soft[channel].zs_channel, R9, NV | MIE);
                        write_zsreg(zs_soft[channel].zs_channel, R0,
                                    RES_EXT_INT);
                        write_zsreg(zs_soft[channel].zs_channel, R0,
                                    RES_EXT_INT);
                }
        }

        for (info = zs_chain, i=0; info; info = info->zs_next, i++) {
                info->magic = SERIAL_MAGIC;
                info->port = (long) info->zs_channel;
                info->line = i;
                info->tty = 0;
                info->irq = zilog_irq;
                info->custom_divisor = 16;
                info->close_delay = 50;
                info->closing_wait = 3000;
                info->x_char = 0;
                info->event = 0;
                info->count = 0;
                info->blocked_open = 0;
                info->tqueue.routine = do_softint;
                info->tqueue.data = info;
                info->tqueue_hangup.routine = do_serial_hangup;
                info->tqueue_hangup.data = info;
                info->callout_termios = callout_driver.init_termios;
                info->normal_termios = serial_driver.init_termios;
                init_waitqueue_head(&info->open_wait);
                init_waitqueue_head(&info->close_wait);
                printk("tty%02d at 0x%04x (irq = %s)", info->line, 
                       info->port, __irq_itoa(info->irq));
                printk(" is a Zilog8530\n");
        }

        restore_flags(flags);

        keyboard_zsinit(kbd_put_char);
        return 0;
}

/* This is called at boot time to prime the kgdb serial debugging
 * serial line.  The 'tty_num' argument is 0 for /dev/ttya and 1
 * for /dev/ttyb which is determined in setup_arch() from the
 * boot command line flags.
 */
static void __init zs_kgdb_hook(int tty_num)
{
        int chip = 0;

        if(!zs_chips[chip]) {
                zs_chips[chip] = get_zs(chip);
                /* Two channels per chip */
                zs_channels[(chip*2)] = &zs_chips[chip]->channelA;
                zs_channels[(chip*2)+1] = &zs_chips[chip]->channelB;
        }
        zs_soft[tty_num].zs_channel = zs_channels[tty_num];
        zs_kgdbchan = zs_soft[tty_num].zs_channel;
        zs_soft[tty_num].change_needed = 0;
        zs_soft[tty_num].clk_divisor = 16;
        zs_soft[tty_num].zs_baud = 9600;
        zs_soft[tty_num].kgdb_channel = 1;     /* This runs kgdb */
        zs_soft[tty_num ^ 1].kgdb_channel = 0; /* This does not */
        /* Turn on transmitter/receiver at 8-bits/char */
        kgdb_chaninit(&zs_soft[tty_num], 0, 9600);
        ZS_CLEARERR(zs_kgdbchan);
        ZS_CLEARFIFO(zs_kgdbchan);
}

#ifdef CONFIG_SERIAL_CONSOLE

/* This is for console output over ttya/ttyb */
static void
zs_console_putchar(struct sun_serial *info, char ch)
{
        int loops = ZS_PUT_CHAR_MAX_DELAY;
        unsigned long flags;

        if(!info->zs_channel)
                return;

        save_flags(flags); cli();
        zs_put_char(info->zs_channel, ch);
        while (!(read_zsreg(info->zs_channel, R1) & ALL_SNT) && --loops)
                udelay(5);
        restore_flags(flags);
}

#ifdef SERIAL_CONSOLE_FAIR_OUTPUT
/*
 * Fair output driver allows a process to speak.
 */
static void zs_fair_output(struct sun_serial *info)
{
        unsigned long flags;
        int left;               /* Output no more than that */
        char c;

        if (info == NULL)
                return;
        if (info->xmit_buf == NULL)
                return;

        save_flags(flags);  cli();
        left = info->xmit_cnt;
        while (left != 0) {
                c = info->xmit_buf[info->xmit_tail];
                info->xmit_tail = (info->xmit_tail+1) & (SERIAL_XMIT_SIZE-1);
                info->xmit_cnt--;
                restore_flags(flags);

                zs_console_putchar(info, c);

                cli();
                left = MIN(info->xmit_cnt, left-1);
        }

        /* Last character is being transmitted now (hopefully). */
        sbus_writeb(RES_Tx_P, &info->zs_channel->control);
        ZSDELAY();
        ZSLOG(REGCTRL, RES_Tx_P, 1);

        restore_flags(flags);
        return;
}
#endif

/*
 * zs_console_write is registered for printk.
 */
static void
zs_console_write(struct console *con, const char *s, unsigned count)
{
        struct sun_serial *info;
        int i;

        info = zs_soft + con->index;

        for (i = 0; i < count; i++, s++) {
                if(*s == '\n')
                        zs_console_putchar(info, '\r');
                zs_console_putchar(info, *s);
        }
#ifdef SERIAL_CONSOLE_FAIR_OUTPUT
        /* Comment this if you want to have a strict interrupt-driven output */
        zs_fair_output(info);
#endif
}

static int
zs_console_wait_key(struct console *con)
{
        sleep_on(&keypress_wait);
        return 0;
}

static kdev_t zs_console_device(struct console *con)
{
        return MKDEV(TTY_MAJOR, 64 + con->index);
}

static int __init zs_console_setup(struct console *con, char *options)
{
        struct sun_serial *info;
        int i, brg, baud;

        info = zs_soft + con->index;
        info->is_cons = 1;

        printk("Console: ttyS%d (Zilog8530)\n", info->line);

        sunserial_console_termios(con);

        i = con->cflag & CBAUD;
        if (con->cflag & CBAUDEX) {
                i &= ~CBAUDEX;
                con->cflag &= ~CBAUDEX;
        }
        baud = baud_table[i];
        info->zs_baud = baud;

        switch (con->cflag & CSIZE) {
                case CS5:
                        zscons_regs[3] = Rx5 | RxENAB;
                        zscons_regs[5] = Tx5 | TxENAB;
                        info->parity_mask = 0x1f;
                        break;
                case CS6:
                        zscons_regs[3] = Rx6 | RxENAB;
                        zscons_regs[5] = Tx6 | TxENAB;
                        info->parity_mask = 0x3f;
                        break;
                case CS7:
                        zscons_regs[3] = Rx7 | RxENAB;
                        zscons_regs[5] = Tx7 | TxENAB;
                        info->parity_mask = 0x7f;
                        break;
                default:
                case CS8:
                        zscons_regs[3] = Rx8 | RxENAB;
                        zscons_regs[5] = Tx8 | TxENAB;
                        info->parity_mask = 0xff;
                        break;
        }
        zscons_regs[5] |= DTR;

        if (con->cflag & PARENB)
                zscons_regs[4] |= PAR_ENAB;
        if (!(con->cflag & PARODD))
                zscons_regs[4] |= PAR_EVEN;

        if (con->cflag & CSTOPB)
                zscons_regs[4] |= SB2;
        else
                zscons_regs[4] |= SB1;

        brg = BPS_TO_BRG(baud, ZS_CLOCK / info->clk_divisor);
        zscons_regs[12] = brg & 0xff;
        zscons_regs[13] = (brg >> 8) & 0xff;

        memcpy(info->curregs, zscons_regs, sizeof(zscons_regs));
        load_zsregs(info, zscons_regs);

        ZS_CLEARERR(info->zs_channel);
        ZS_CLEARFIFO(info->zs_channel);
        return 0;
}

static struct console zs_console = {
        name:           "ttyS",
        write:          zs_console_write,
        device:         zs_console_device,
        wait_key:       zs_console_wait_key,
        setup:          zs_console_setup,
        flags:          CON_PRINTBUFFER,
        index:          -1,
};

static int __init zs_console_init(void)
{
        extern int con_is_present(void);

        if (con_is_present())
                return 0;

        zs_console.index = serial_console - 1;
        register_console(&zs_console);
        return 0;
}

#endif /* CONFIG_SERIAL_CONSOLE */