Ok. I didn't make 2.4.0 in 2000. Tough. I tried, but we had some

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

/* $Id: su.c,v 1.43 2000/11/15 07:28:09 davem Exp $
 * su.c: Small serial driver for keyboard/mouse interface on sparc32/PCI
 *
 * Copyright (C) 1997  Eddie C. Dost  (ecd@skynet.be)
 * Copyright (C) 1998-1999  Pete Zaitcev   (zaitcev@metabyte.com)
 *
 * This is mainly a variation of drivers/char/serial.c,
 * credits go to authors mentioned therein.
 */

/*
 * Configuration section.
 */
#define SERIAL_PARANOIA_CHECK
#define CONFIG_SERIAL_NOPAUSE_IO        /* Unused on sparc */
#define SERIAL_DO_RESTART

/* Set of debugging defines */

#undef SERIAL_DEBUG_INTR
#undef SERIAL_DEBUG_OPEN
#undef SERIAL_DEBUG_FLOW
#undef SERIAL_DEBUG_RS_WAIT_UNTIL_SENT
#undef SERIAL_DEBUG_THROTTLE

#define RS_ISR_PASS_LIMIT 256

/*
 * 0x20 is sun4m thing, Dave Redman heritage.
 * See arch/sparc/kernel/irq.c.
 */
#define IRQ_4M(n)       ((n)|0x20)

#if defined(MODULE) && defined(SERIAL_DEBUG_MCOUNT)
#define DBG_CNT(s)                                                      \
do {                                                                    \
        printk("(%s): [%x] refc=%d, serc=%d, ttyc=%d -> %s\n",          \
               kdevname(tty->device), (info->flags), serial_refcount,   \
               info->count,tty->count,s);                               \
} while (0)
#else
#define DBG_CNT(s)
#endif

/*
 * End of serial driver configuration section.
 */
#include <linux/config.h>
#include <linux/module.h>
#include <linux/errno.h>
#include <linux/signal.h>
#include <linux/sched.h>
#include <linux/interrupt.h>
#include <linux/tty.h>
#include <linux/tty_flip.h>
#include <linux/serial.h>
#include <linux/serialP.h>
#include <linux/serial_reg.h>
#include <linux/string.h>
#include <linux/fcntl.h>
#include <linux/ptrace.h>
#include <linux/ioport.h>
#include <linux/mm.h>
#include <linux/malloc.h>
#include <linux/init.h>
#include <linux/bootmem.h>
#include <linux/delay.h>
#ifdef CONFIG_SERIAL_CONSOLE
#include <linux/console.h>
#include <linux/major.h>
#endif
#include <linux/sysrq.h>

#include <asm/system.h>
#include <asm/oplib.h>
#include <asm/io.h>
#include <asm/ebus.h>
#include <asm/irq.h>
#include <asm/uaccess.h>
#include <asm/bitops.h>

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

/* We are on a NS PC87303 clocked with 24.0 MHz, which results
 * in a UART clock of 1.8462 MHz.
 */
#define BAUD_BASE       (1846200 / 16)

#ifdef CONFIG_SERIAL_CONSOLE
extern int serial_console;
static struct console sercons;
int su_serial_console_init(void);
#endif

enum su_type { SU_PORT_NONE, SU_PORT_MS, SU_PORT_KBD, SU_PORT_PORT };
static char *su_typev[] = { "???", "mouse", "kbd", "serial" };

#define SU_PROPSIZE     128

/*
 * serial.c saves memory when it allocates async_info upon first open.
 * We have parts of state structure together because we do call startup
 * for keyboard and mouse.
 */
struct su_struct {
        int              magic;
        unsigned long    port;
        int              baud_base;
        int              type;          /* Hardware type: e.g. 16550 */
        int              irq;
        int              flags;
        int              line;
        int              cflag;

        enum su_type     port_type;     /* Hookup type: e.g. mouse */
        int              is_console;
        int              port_node;

        char             name[16];

        int              xmit_fifo_size;
        int              custom_divisor;
        unsigned short   close_delay;
        unsigned short   closing_wait;  /* time to wait before closing */

        struct tty_struct       *tty;
        int                     read_status_mask;
        int                     ignore_status_mask;
        int                     timeout;
        int                     quot;
        int                     x_char; /* xon/xoff character */
        int                     IER;    /* Interrupt Enable Register */
        int                     MCR;    /* Modem control register */
        unsigned long           event;
        int                     blocked_open; /* # of blocked opens */
        long                    session; /* Session of opening process */
        long                    pgrp; /* pgrp of opening process */
        unsigned char           *xmit_buf;
        int                     xmit_head;
        int                     xmit_tail;
        int                     xmit_cnt;
        struct tq_struct        tqueue;
        wait_queue_head_t       open_wait;
        wait_queue_head_t       close_wait;
        wait_queue_head_t       delta_msr_wait;

        int                     count;
        struct async_icount     icount;
        struct termios          normal_termios, callout_termios;
        unsigned long           last_active;    /* For async_struct, to be */
};

/*
 * Scan status structure.
 * "prop" is a local variable but it eats stack to keep it in each
 * stack frame of a recursive procedure.
 */
struct su_probe_scan {
        int msnode, kbnode;     /* PROM nodes for mouse and keyboard */
        int msx, kbx;           /* minors for mouse and keyboard */
        int devices;            /* scan index */
        char prop[SU_PROPSIZE];
};

static char *serial_name = "PCIO serial driver";
static char serial_version[16];

static DECLARE_TASK_QUEUE(tq_serial);

static struct tty_driver serial_driver, callout_driver;
static int serial_refcount;

/* number of characters left in xmit buffer before we ask for more */
#define WAKEUP_CHARS 256

static void autoconfig(struct su_struct *info);
static void change_speed(struct su_struct *info, struct termios *old);
static void su_wait_until_sent(struct tty_struct *tty, int timeout);

/*
 * Here we define the default xmit fifo size used for each type of
 * UART
 */
static struct serial_uart_config uart_config[] = {
        { "unknown", 1, 0 }, 
        { "8250", 1, 0 }, 
        { "16450", 1, 0 }, 
        { "16550", 1, 0 }, 
        { "16550A", 16, UART_CLEAR_FIFO | UART_USE_FIFO }, 
        { "cirrus", 1, 0 }, 
        { "ST16650", 1, UART_CLEAR_FIFO |UART_STARTECH }, 
        { "ST16650V2", 32, UART_CLEAR_FIFO | UART_USE_FIFO |
                  UART_STARTECH }, 
        { "TI16750", 64, UART_CLEAR_FIFO | UART_USE_FIFO},
        { 0, 0}
};


#define NR_PORTS        4

static struct su_struct su_table[NR_PORTS];
static struct tty_struct *serial_table[NR_PORTS];
static struct termios *serial_termios[NR_PORTS];
static struct termios *serial_termios_locked[NR_PORTS];

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

/*
 * tmp_buf is used as a temporary buffer by serial_write.  We need to
 * lock it in case the copy_from_user 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;
static DECLARE_MUTEX(tmp_buf_sem);

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

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

static inline
unsigned int su_inb(struct su_struct *info, unsigned long offset)
{
        return inb(info->port + offset);
}

static inline void
su_outb(struct su_struct *info, unsigned long offset, int value)
{
#ifndef __sparc_v9__
        /*
         * MrCoffee has weird schematics: IRQ4 & P10(?) pins of SuperIO are
         * connected with a gate then go to SlavIO. When IRQ4 goes tristated
         * gate outputs a logical one. Since we use level triggered interrupts
         * we have lockup and watchdog reset. We cannot mask IRQ because
         * keyboard shares IRQ with us (Word has it as Bob Smelik's design).
         * This problem is similar to what Alpha people suffer, see serial.c.
         */
        if (offset == UART_MCR) value |= UART_MCR_OUT2;
#endif
        outb(value, info->port + offset);
}

#define serial_in(info, off)            su_inb(info, off)
#define serial_inp(info, off)           su_inb(info, off)
#define serial_out(info, off, val)      su_outb(info, off, val)
#define serial_outp(info, off, val)     su_outb(info, off, val)

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

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

        save_flags(flags); cli();
        if (info->IER & UART_IER_THRI) {
                info->IER &= ~UART_IER_THRI;
                serial_out(info, UART_IER, info->IER);
        }
        restore_flags(flags);
}

static void su_start(struct tty_struct *tty)
{
        struct su_struct *info = (struct su_struct *)tty->driver_data;
        unsigned long flags;
        
        if (serial_paranoia_check(info, tty->device, "su_start"))
                return;

        save_flags(flags); cli();
        if (info->xmit_cnt && info->xmit_buf && !(info->IER & UART_IER_THRI)) {
                info->IER |= UART_IER_THRI;
                serial_out(info, UART_IER, info->IER);
        }
        restore_flags(flags);
}

/*
 * ----------------------------------------------------------------------
 *
 * Here starts the interrupt handling routines.  All of the following
 * subroutines are declared as inline and are folded into
 * su_interrupt().  They were separated out for readability's sake.
 *
 * Note: rs_interrupt() is a "fast" interrupt, which means that it
 * runs with interrupts turned off.  People who may want to modify
 * rs_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
su_sched_event(struct su_struct *info, int event)
{
        info->event |= 1 << event;
        queue_task(&info->tqueue, &tq_serial);
        mark_bh(SERIAL_BH);
}

static __inline__ void
receive_kbd_ms_chars(struct su_struct *info, struct pt_regs *regs, int is_brk)
{
        unsigned char status = 0;
        unsigned char ch;

        do {
                ch = serial_inp(info, UART_RX);
                if (info->port_type == SU_PORT_KBD) {
                        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);
                } else {
                        sun_mouse_inbyte(ch, is_brk);
                }

                status = su_inb(info, UART_LSR);
        } while (status & UART_LSR_DR);
}

static __inline__ void
receive_serial_chars(struct su_struct *info, int *status, struct pt_regs *regs)
{
        struct tty_struct *tty = info->tty;
        unsigned char ch;
        int ignored = 0, saw_console_brk = 0;
        struct  async_icount *icount;

        icount = &info->icount;
        do {
                ch = serial_inp(info, UART_RX);
                if (info->is_console &&
                    (ch == 0 || (*status &UART_LSR_BI)))
                        saw_console_brk = 1;
                if (tty->flip.count >= TTY_FLIPBUF_SIZE)
                        break;
                *tty->flip.char_buf_ptr = ch;
                icount->rx++;

#ifdef SERIAL_DEBUG_INTR
                printk("D%02x:%02x.", ch, *status);
#endif
                *tty->flip.flag_buf_ptr = 0;
                if (*status & (UART_LSR_BI | UART_LSR_PE |
                               UART_LSR_FE | UART_LSR_OE)) {
                        /*
                         * For statistics only
                         */
                        if (*status & UART_LSR_BI) {
                                *status &= ~(UART_LSR_FE | UART_LSR_PE);
                                icount->brk++;
                        } else if (*status & UART_LSR_PE)
                                icount->parity++;
                        else if (*status & UART_LSR_FE)
                                icount->frame++;
                        if (*status & UART_LSR_OE)
                                icount->overrun++;

                        /*
                         * Now check to see if character should be
                         * ignored, and mask off conditions which
                         * should be ignored.
                         */
                        if (*status & info->ignore_status_mask) {
                                if (++ignored > 100) {
#ifdef SERIAL_DEBUG_INTR
                                        printk("ign100..");
#endif
                                        break;
                                }
                                goto ignore_char;
                        }
                        *status &= info->read_status_mask;

                        if (*status & (UART_LSR_BI)) {
#ifdef SERIAL_DEBUG_INTR
                                printk("handling break....");
#endif
                                *tty->flip.flag_buf_ptr = TTY_BREAK;
                                if (info->flags & ASYNC_SAK)
                                        do_SAK(tty);
                        } else if (*status & UART_LSR_PE)
                                *tty->flip.flag_buf_ptr = TTY_PARITY;
                        else if (*status & UART_LSR_FE)
                                *tty->flip.flag_buf_ptr = TTY_FRAME;
                        if (*status & UART_LSR_OE) {
                                /*
                                 * Overrun is special, since it's
                                 * reported immediately, and doesn't
                                 * affect the current character
                                 */
                                if (tty->flip.count < TTY_FLIPBUF_SIZE) {
                                        tty->flip.count++;
                                        tty->flip.flag_buf_ptr++;
                                        tty->flip.char_buf_ptr++;
                                        *tty->flip.flag_buf_ptr = TTY_OVERRUN;
                                }
                        }
                }
                tty->flip.flag_buf_ptr++;
                tty->flip.char_buf_ptr++;
                tty->flip.count++;
        ignore_char:
                *status = serial_inp(info, UART_LSR);
        } while (*status & UART_LSR_DR);
#ifdef SERIAL_DEBUG_INTR
        printk("E%02x.R%d", *status, tty->flip.count);
#endif
        tty_flip_buffer_push(tty);
        if (saw_console_brk != 0)
                batten_down_hatches();
}

static __inline__ void
transmit_chars(struct su_struct *info, int *intr_done)
{
        int count;

        if (info->x_char) {
                serial_outp(info, UART_TX, info->x_char);
                info->icount.tx++;
                info->x_char = 0;
                if (intr_done)
                        *intr_done = 0;
                return;
        }
        if ((info->xmit_cnt <= 0) || info->tty->stopped ||
            info->tty->hw_stopped) {
                info->IER &= ~UART_IER_THRI;
                serial_out(info, UART_IER, info->IER);
                return;
        }

        count = info->xmit_fifo_size;
        do {
                serial_out(info, UART_TX, info->xmit_buf[info->xmit_tail++]);
                info->xmit_tail = info->xmit_tail & (SERIAL_XMIT_SIZE-1);
                info->icount.tx++;
                if (--info->xmit_cnt <= 0)
                        break;
        } while (--count > 0);
        
        if (info->xmit_cnt < WAKEUP_CHARS)
                su_sched_event(info, RS_EVENT_WRITE_WAKEUP);

#ifdef SERIAL_DEBUG_INTR
        printk("T%d...", info->xmit_cnt);
#endif
        if (intr_done)
                *intr_done = 0;

        if (info->xmit_cnt <= 0) {
                info->IER &= ~UART_IER_THRI;
                serial_out(info, UART_IER, info->IER);
        }
}

static __inline__ void
check_modem_status(struct su_struct *info)
{
        int     status;
        struct  async_icount *icount;

        status = serial_in(info, UART_MSR);

        if (status & UART_MSR_ANY_DELTA) {
                icount = &info->icount;
                /* update input line counters */
                if (status & UART_MSR_TERI)
                        icount->rng++;
                if (status & UART_MSR_DDSR)
                        icount->dsr++;
                if (status & UART_MSR_DDCD) {
                        icount->dcd++;
#ifdef CONFIG_HARD_PPS
                        if ((info->flags & ASYNC_HARDPPS_CD) &&
                            (status & UART_MSR_DCD))
                                hardpps();
#endif
                }
                if (status & UART_MSR_DCTS)
                        icount->cts++;
                wake_up_interruptible(&info->delta_msr_wait);
        }

        if ((info->flags & ASYNC_CHECK_CD) && (status & UART_MSR_DDCD)) {
#if (defined(SERIAL_DEBUG_OPEN) || defined(SERIAL_DEBUG_INTR))
                printk("ttys%d CD now %s...", info->line,
                       (status & UART_MSR_DCD) ? "on" : "off");
#endif          
                if (status & UART_MSR_DCD)
                        wake_up_interruptible(&info->open_wait);
                else if (!((info->flags & ASYNC_CALLOUT_ACTIVE) &&
                           (info->flags & ASYNC_CALLOUT_NOHUP))) {
#ifdef SERIAL_DEBUG_OPEN
                        printk("doing serial hangup...");
#endif
                        if (info->tty)
                                tty_hangup(info->tty);
        }
        }
        if (info->flags & ASYNC_CTS_FLOW) {
                if (info->tty->hw_stopped) {
                        if (status & UART_MSR_CTS) {
#if (defined(SERIAL_DEBUG_INTR) || defined(SERIAL_DEBUG_FLOW))
                                printk("CTS tx start...");
#endif
                                info->tty->hw_stopped = 0;
                                info->IER |= UART_IER_THRI;
                                serial_out(info, UART_IER, info->IER);
                                su_sched_event(info, RS_EVENT_WRITE_WAKEUP);
                                return;
                        }
                } else {
                        if (!(status & UART_MSR_CTS)) {
#if (defined(SERIAL_DEBUG_INTR) || defined(SERIAL_DEBUG_FLOW))
                                printk("CTS tx stop...");
#endif
                                info->tty->hw_stopped = 1;
                                info->IER &= ~UART_IER_THRI;
                                serial_out(info, UART_IER, info->IER);
                        }
                }
        }
}

/*
 * This is the kbd/mouse serial driver's interrupt routine
 */
static void
su_kbd_ms_interrupt(int irq, void *dev_id, struct pt_regs * regs)
{
        struct su_struct *info = (struct su_struct *)dev_id;
        unsigned char status;

#ifdef SERIAL_DEBUG_INTR
        printk("su_kbd_ms_interrupt(%s)...", __irq_itoa(irq));
#endif
        if (!info)
                return;

        if (serial_in(info, UART_IIR) & UART_IIR_NO_INT)
                return;

        status = serial_inp(info, UART_LSR);
#ifdef SERIAL_DEBUG_INTR
        printk("status = %x...", status);
#endif
        if ((status & UART_LSR_DR) || (status & UART_LSR_BI))
                receive_kbd_ms_chars(info, regs,
                                     (status & UART_LSR_BI) != 0);

#ifdef SERIAL_DEBUG_INTR
        printk("end.\n");
#endif
}

/*
 * This is the serial driver's generic interrupt routine
 */
static void
su_serial_interrupt(int irq, void *dev_id, struct pt_regs * regs)
{
        int status;
        struct su_struct *info;
        int pass_counter = 0;

#ifdef SERIAL_DEBUG_INTR
        printk("su_serial_interrupt(%s)...", __irq_itoa(irq));
#endif
        info = (struct su_struct *)dev_id;
        if (!info || !info->tty) {
#ifdef SERIAL_DEBUG_INTR
                printk("strain\n");
#endif
                return;
        }

        do {
                status = serial_inp(info, UART_LSR);
#ifdef SERIAL_DEBUG_INTR
                printk("status = %x...", status);
#endif
                if (status & UART_LSR_DR)
                        receive_serial_chars(info, &status, regs);
                check_modem_status(info);
                if (status & UART_LSR_THRE)
                        transmit_chars(info, 0);

                if (pass_counter++ > RS_ISR_PASS_LIMIT) {
#ifdef SERIAL_DEBUG_INTR
                        printk("rs loop break");
#endif
                        break;  /* Prevent infinite loops */
                }
        } while (!(serial_in(info, UART_IIR) & UART_IIR_NO_INT));

        info->last_active = jiffies;

#ifdef SERIAL_DEBUG_INTR
        printk("end.\n");
#endif
}

/*
 * -------------------------------------------------------------------
 * 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
 * su_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 su_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 su_struct        *info = (struct su_struct *) 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);
        }
}

/*
 * ---------------------------------------------------------------
 * Low level utility subroutines for the serial driver:  routines to
 * figure out the appropriate timeout for an interrupt chain, routines
 * to initialize and startup a serial port, and routines to shutdown a
 * serial port.  Useful stuff like that.
 * ---------------------------------------------------------------
 */

static int
startup(struct su_struct *info)
{
        unsigned long flags;
        int     retval=0;
        unsigned long page;

        save_flags(flags);
        if (info->tty) {
                page = get_free_page(GFP_KERNEL);
                if (!page)
                        return -ENOMEM;

                cli();

                if (info->flags & ASYNC_INITIALIZED) {
                        free_page(page);
                        goto errout;
                }

                if (info->port == 0 || info->type == PORT_UNKNOWN) {
                        set_bit(TTY_IO_ERROR, &info->tty->flags);
                        free_page(page);
                        goto errout;
                }
                if (info->xmit_buf)
                        free_page(page);
                else
                        info->xmit_buf = (unsigned char *) page;
        }
        cli();

#ifdef SERIAL_DEBUG_OPEN
        printk("starting up ttys%d (irq %s)...", info->line,
               __irq_itoa(info->irq));
#endif

        if (uart_config[info->type].flags & UART_STARTECH) {
                /* Wake up UART */
                serial_outp(info, UART_LCR, 0xBF);
                serial_outp(info, UART_EFR, UART_EFR_ECB);
                serial_outp(info, UART_IER, 0);
                serial_outp(info, UART_EFR, 0);
                serial_outp(info, UART_LCR, 0);
        }

        if (info->type == PORT_16750) {
                /* Wake up UART */
                serial_outp(info, UART_IER, 0);
        }

        /*
         * Clear the FIFO buffers and disable them
         * (they will be reenabled in change_speed())
         */
        if (uart_config[info->type].flags & UART_CLEAR_FIFO)
                serial_outp(info, UART_FCR, (UART_FCR_CLEAR_RCVR |
                                             UART_FCR_CLEAR_XMIT));

        /*
         * At this point there's no way the LSR could still be 0xFF;
         * if it is, then bail out, because there's likely no UART
         * here.
         */
        if (serial_inp(info, UART_LSR) == 0xff) {
                if (capable(CAP_SYS_ADMIN)) {
                        if (info->tty)
                                set_bit(TTY_IO_ERROR, &info->tty->flags);
                } else
                        retval = -ENODEV;
                goto errout;
        }

        /*
         * Allocate the IRQ if necessary
         */
        if (info->port_type != SU_PORT_PORT) {
                retval = request_irq(info->irq, su_kbd_ms_interrupt,
                                     SA_SHIRQ, info->name, info);
        } else {
                retval = request_irq(info->irq, su_serial_interrupt,
                                     SA_SHIRQ, info->name, info);
        }
        if (retval) {
                if (capable(CAP_SYS_ADMIN)) {
                        if (info->tty)
                                set_bit(TTY_IO_ERROR, &info->tty->flags);
                        retval = 0;
                }
                goto errout;
        }

        /*
         * Clear the interrupt registers.
         */
        (void) serial_inp(info, UART_RX);
        (void) serial_inp(info, UART_IIR);
        (void) serial_inp(info, UART_MSR);

        /*
         * Now, initialize the UART 
         */
        serial_outp(info, UART_LCR, UART_LCR_WLEN8);    /* reset DLAB */

        info->MCR = 0;
        if (info->tty && info->tty->termios->c_cflag & CBAUD)
                info->MCR = UART_MCR_DTR | UART_MCR_RTS;
        if (info->irq != 0)
                info->MCR |= UART_MCR_OUT2;
        serial_outp(info, UART_MCR, info->MCR);

        /*
         * Finally, enable interrupts
         */
        info->IER = UART_IER_MSI | UART_IER_RLSI | UART_IER_RDI;
        serial_outp(info, UART_IER, info->IER); /* enable interrupts */

        /*
         * And clear the interrupt registers again for luck.
         */
        (void)serial_inp(info, UART_LSR);
        (void)serial_inp(info, UART_RX);
        (void)serial_inp(info, UART_IIR);
        (void)serial_inp(info, UART_MSR);

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

        /*
         * Set up the tty->alt_speed kludge
         */
        if (info->tty) {
                if ((info->flags & ASYNC_SPD_MASK) == ASYNC_SPD_HI)
                        info->tty->alt_speed = 57600;
                if ((info->flags & ASYNC_SPD_MASK) == ASYNC_SPD_VHI)
                        info->tty->alt_speed = 115200;
                if ((info->flags & ASYNC_SPD_MASK) == ASYNC_SPD_SHI)
                        info->tty->alt_speed = 230400;
                if ((info->flags & ASYNC_SPD_MASK) == ASYNC_SPD_WARP)
                        info->tty->alt_speed = 460800;
        }

        /*
         * and set the speed of the serial port
         */
        change_speed(info, 0);

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

errout:
        restore_flags(flags);
        return retval;
}

/*
 * 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 su_struct *info)
{
        unsigned long   flags;

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

        save_flags(flags); cli(); /* Disable interrupts */

        /*
         * clear delta_msr_wait queue to avoid mem leaks: we may free the irq
         * here so the queue might never be waken up
         */
        wake_up_interruptible(&info->delta_msr_wait);
        
        /*
         * Free the IRQ, if necessary
         */
        free_irq(info->irq, info);

        if (info->xmit_buf) {
                free_page((unsigned long) info->xmit_buf);
                info->xmit_buf = 0;
        }

        info->IER = 0;
        serial_outp(info, UART_IER, 0x00);      /* disable all intrs */
        info->MCR &= ~UART_MCR_OUT2;

        /* disable break condition */
        serial_out(info, UART_LCR, serial_inp(info, UART_LCR) & ~UART_LCR_SBC);

        if (!info->tty || (info->tty->termios->c_cflag & HUPCL))
                info->MCR &= ~(UART_MCR_DTR|UART_MCR_RTS);
        serial_outp(info, UART_MCR, info->MCR);

        /* disable FIFO's */    
        serial_outp(info, UART_FCR, (UART_FCR_CLEAR_RCVR |
                                     UART_FCR_CLEAR_XMIT));
        (void)serial_in(info, UART_RX);    /* read data port to reset things */

        if (info->tty)
                set_bit(TTY_IO_ERROR, &info->tty->flags);

        if (uart_config[info->type].flags & UART_STARTECH) {
                /* Arrange to enter sleep mode */
                serial_outp(info, UART_LCR, 0xBF);
                serial_outp(info, UART_EFR, UART_EFR_ECB);
                serial_outp(info, UART_IER, UART_IERX_SLEEP);
                serial_outp(info, UART_LCR, 0);
        }
        if (info->type == PORT_16750) {
                /* Arrange to enter sleep mode */
                serial_outp(info, UART_IER, UART_IERX_SLEEP);
        }
        info->flags &= ~ASYNC_INITIALIZED;
        restore_flags(flags);
}

static __inline__ int
su_get_baud_rate(struct su_struct *info)
{
        static int baud_table[] = {
                0, 50, 75, 110, 134, 150, 200, 300, 600, 1200, 1800, 2400,
                4800, 9600, 19200, 38400, 57600, 115200, 230400, 460800, 0
        };
        int i;

        if (info->tty)
                return tty_get_baud_rate(info->tty);

        i = info->cflag & CBAUD;
        if (i & CBAUDEX) {
                i &= ~(CBAUDEX);
                if (i < 1 || i > 4)
                        info->cflag &= ~(CBAUDEX);
                else
                        i += 15;
        }
        return baud_table[i];
}

/*
 * 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 su_struct *info,
             struct termios *old_termios)
{
        int             quot = 0, baud;
        unsigned int    cval, fcr = 0;
        int             bits;
        unsigned long   flags;

        if (info->port_type == SU_PORT_PORT) {
                if (!info->tty || !info->tty->termios)
                        return;
                if (!info->port)
                        return;
                info->cflag = info->tty->termios->c_cflag;
        }

        /* byte size and parity */
        switch (info->cflag & CSIZE) {
              case CS5: cval = 0x00; bits = 7; break;
              case CS6: cval = 0x01; bits = 8; break;
              case CS7: cval = 0x02; bits = 9; break;
              case CS8: cval = 0x03; bits = 10; break;
                /* Never happens, but GCC is too dumb to figure it out */
              default:  cval = 0x00; bits = 7; break;
        }
        if (info->cflag & CSTOPB) {
                cval |= 0x04;
                bits++;
        }
        if (info->cflag & PARENB) {
                cval |= UART_LCR_PARITY;
                bits++;
        }
        if (!(info->cflag & PARODD))
                cval |= UART_LCR_EPAR;
#ifdef CMSPAR
        if (info->cflag & CMSPAR)
                cval |= UART_LCR_SPAR;
#endif

        /* Determine divisor based on baud rate */
        baud = su_get_baud_rate(info);
        if (baud == 38400 &&
            ((info->flags & ASYNC_SPD_MASK) == ASYNC_SPD_CUST))
                quot = info->custom_divisor;
        else {
                if (baud == 134)
                        /* Special case since 134 is really 134.5 */
                        quot = (2 * info->baud_base / 269);
                else if (baud)
                        quot = info->baud_base / baud;
        }
        /* If the quotient is zero refuse the change */
        if (!quot && old_termios) {
                info->tty->termios->c_cflag &= ~CBAUD;
                info->tty->termios->c_cflag |= (old_termios->c_cflag & CBAUD);
                baud = tty_get_baud_rate(info->tty);
                if (!baud)
                        baud = 9600;
                if (baud == 38400 &&
                    ((info->flags & ASYNC_SPD_MASK) == ASYNC_SPD_CUST))
                        quot = info->custom_divisor;
                else {
                        if (baud == 134)
                                /* Special case since 134 is really 134.5 */
                                quot = (2*info->baud_base / 269);
                        else if (baud)
                                quot = info->baud_base / baud;
                }
        }
        /* As a last resort, if the quotient is zero, default to 9600 bps */
        if (!quot)
                quot = info->baud_base / 9600;
        info->timeout = ((info->xmit_fifo_size*HZ*bits*quot) / info->baud_base);
        info->timeout += HZ/50;         /* Add .02 seconds of slop */

        /* Set up FIFO's */
        if (uart_config[info->type].flags & UART_USE_FIFO) {
                if ((info->baud_base / quot) < 9600)
                        fcr = UART_FCR_ENABLE_FIFO | UART_FCR_TRIGGER_1;
                else
                        fcr = UART_FCR_ENABLE_FIFO | UART_FCR_TRIGGER_8;
        }
        if (info->type == PORT_16750)
                fcr |= UART_FCR7_64BYTE;

        /* CTS flow control flag and modem status interrupts */
        info->IER &= ~UART_IER_MSI;
        if (info->flags & ASYNC_HARDPPS_CD)
                info->IER |= UART_IER_MSI;
        if (info->cflag & CRTSCTS) {
                info->flags |= ASYNC_CTS_FLOW;
                info->IER |= UART_IER_MSI;
        } else
                info->flags &= ~ASYNC_CTS_FLOW;
        if (info->cflag & CLOCAL)
                info->flags &= ~ASYNC_CHECK_CD;
        else {
                info->flags |= ASYNC_CHECK_CD;
                info->IER |= UART_IER_MSI;
        }
        serial_out(info, UART_IER, info->IER);

        /*
         * Set up parity check flag
         */
        if (info->tty) {
#define RELEVANT_IFLAG(iflag) (iflag & (IGNBRK|BRKINT|IGNPAR|PARMRK|INPCK))

                info->read_status_mask = UART_LSR_OE | UART_LSR_THRE |
                                         UART_LSR_DR;
                if (I_INPCK(info->tty))
                        info->read_status_mask |= UART_LSR_FE | UART_LSR_PE;
                if (I_BRKINT(info->tty) || I_PARMRK(info->tty))
                        info->read_status_mask |= UART_LSR_BI;

                /*
                 * Characters to ignore
                 */
                info->ignore_status_mask = 0;
                if (I_IGNPAR(info->tty))
                        info->ignore_status_mask |= UART_LSR_PE | UART_LSR_FE;
                if (I_IGNBRK(info->tty)) {
                        info->ignore_status_mask |= UART_LSR_BI;
                        /*
                         * If we're ignore parity and break indicators, ignore 
                         * overruns too.  (For real raw support).
                         */
                        if (I_IGNPAR(info->tty))
                                info->ignore_status_mask |= UART_LSR_OE;
                }
                /*
                 * !!! ignore all characters if CREAD is not set
                 */
                if ((info->cflag & CREAD) == 0)
                        info->ignore_status_mask |= UART_LSR_DR;
        }

        save_flags(flags); cli();
        if (uart_config[info->type].flags & UART_STARTECH) {
                serial_outp(info, UART_LCR, 0xBF);
                serial_outp(info, UART_EFR,
                            (info->cflag & CRTSCTS) ? UART_EFR_CTS : 0);
        }
        serial_outp(info, UART_LCR, cval | UART_LCR_DLAB);      /* set DLAB */
        serial_outp(info, UART_DLL, quot & 0xff);       /* LS of divisor */
        serial_outp(info, UART_DLM, quot >> 8);         /* MS of divisor */
        if (info->type == PORT_16750)
                serial_outp(info, UART_FCR, fcr);       /* set fcr */
        serial_outp(info, UART_LCR, cval);              /* reset DLAB */
        if (info->type != PORT_16750)
                serial_outp(info, UART_FCR, fcr);       /* set fcr */
        restore_flags(flags);
        info->quot = quot;
}

static void
su_put_char(struct tty_struct *tty, unsigned char ch)
{
        struct su_struct *info = (struct su_struct *)tty->driver_data;
        unsigned long flags;

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

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

        save_flags(flags); cli();
        if (info->xmit_cnt >= SERIAL_XMIT_SIZE - 1) {
                restore_flags(flags);
                return;
        }

        info->xmit_buf[info->xmit_head++] = ch;
        info->xmit_head &= SERIAL_XMIT_SIZE-1;
        info->xmit_cnt++;
        restore_flags(flags);
}

static void su_put_char_kbd(unsigned char c)
{
        struct su_struct *info = su_table;
        int lsr;

        if (info->port_type != SU_PORT_KBD)
                ++info;
        if (info->port_type != SU_PORT_KBD)
                return;

        do {
                lsr = serial_in(info, UART_LSR);
        } while (!(lsr & UART_LSR_THRE));

        /* Send the character out. */
        su_outb(info, UART_TX, c);
}

static void
su_change_mouse_baud(int baud)
{
        struct su_struct *info = su_table;

        if (info->port_type != SU_PORT_MS)
                ++info;
        if (info->port_type != SU_PORT_MS)
                return;

        info->cflag &= ~(CBAUDEX | CBAUD);
        switch(baud) {
                case 1200:
                        info->cflag |= B1200;
                        break;
                case 2400:
                        info->cflag |= B2400;
                        break;
                case 4800:
                        info->cflag |= B4800;
                        break;
                case 9600:
                        info->cflag |= B9600;
                        break;
                default:
                        printk("su_change_mouse_baud: unknown baud rate %d, "
                               "defaulting to 1200\n", baud);
                        info->cflag |= 1200;
                        break;
        }
        change_speed(info, 0);
}

static void
su_flush_chars(struct tty_struct *tty)
{
        struct su_struct *info = (struct su_struct *)tty->driver_data;
        unsigned long flags;
                                
        if (serial_paranoia_check(info, tty->device, "su_flush_chars"))
                return;

        if (info->xmit_cnt <= 0 || tty->stopped || tty->hw_stopped ||
            !info->xmit_buf)
                return;

        save_flags(flags); cli();
        info->IER |= UART_IER_THRI;
        serial_out(info, UART_IER, info->IER);
        restore_flags(flags);
}

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

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

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

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

                        c -= copy_from_user(tmp_buf, buf, c);
                        if (!c) {
                                if (!ret)
                                        ret = -EFAULT;
                                break;
                        }
                        cli();
                        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);
                        info->xmit_head = ((info->xmit_head + c) &
                                           (SERIAL_XMIT_SIZE-1));
                        info->xmit_cnt += c;
                        restore_flags(flags);
                        buf += c;
                        count -= c;
                        ret += c;
                }
                up(&tmp_buf_sem);
        } else {
                while (1) {
                        cli();          
                        c = MIN(count,
                                MIN(SERIAL_XMIT_SIZE - info->xmit_cnt - 1,
                                    SERIAL_XMIT_SIZE - info->xmit_head));
                        if (c <= 0) {
                                restore_flags(flags);
                                break;
                        }
                        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;
                        ret += c;
                }
        }
        if (info->xmit_cnt && !tty->stopped && !tty->hw_stopped &&
            !(info->IER & UART_IER_THRI)) {
                info->IER |= UART_IER_THRI;
                serial_out(info, UART_IER, info->IER);
        }
        return ret;
}

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

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

static int
su_chars_in_buffer(struct tty_struct *tty)
{
        struct su_struct *info = (struct su_struct *)tty->driver_data;
                                
        if (serial_paranoia_check(info, tty->device, "su_chars_in_buffer"))
                return 0;
        return info->xmit_cnt;
}

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

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

/*
 * This function is used to send a high-priority XON/XOFF character to
 * the device
 */
static void
su_send_xchar(struct tty_struct *tty, char ch)
{
        struct su_struct *info = (struct su_struct *)tty->driver_data;

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

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

        info->x_char = ch;
        if (ch) {
                /* Make sure transmit interrupts are on */
                info->IER |= UART_IER_THRI;
                serial_out(info, UART_IER, info->IER);
        }
}

/*
 * ------------------------------------------------------------
 * su_throttle()
 * 
 * This routine is called by the upper-layer tty layer to signal that
 * incoming characters should be throttled.
 * ------------------------------------------------------------
 */
static void
su_throttle(struct tty_struct * tty)
{
        struct su_struct *info = (struct su_struct *)tty->driver_data;
        unsigned long flags;
#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, "su_throttle"))
                return;

        if (I_IXOFF(tty))
                su_send_xchar(tty, STOP_CHAR(tty));

        if (tty->termios->c_cflag & CRTSCTS)
                info->MCR &= ~UART_MCR_RTS;

        save_flags(flags); cli();
        serial_out(info, UART_MCR, info->MCR);
        restore_flags(flags);
}

static void
su_unthrottle(struct tty_struct * tty)
{
        struct su_struct *info = (struct su_struct *)tty->driver_data;
        unsigned long flags;
#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, "su_unthrottle"))
                return;

        if (I_IXOFF(tty)) {
                if (info->x_char)
                        info->x_char = 0;
                else
                        su_send_xchar(tty, START_CHAR(tty));
        }
        if (tty->termios->c_cflag & CRTSCTS)
                info->MCR |= UART_MCR_RTS;
        save_flags(flags); cli();
        serial_out(info, UART_MCR, info->MCR);
        restore_flags(flags);
}

/*
 * ------------------------------------------------------------
 * su_ioctl() and friends
 * ------------------------------------------------------------
 */

/*
 * 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 su_struct * info, unsigned int *value)
{
        unsigned char status;
        unsigned int result;
        unsigned long flags;

        save_flags(flags); cli();
        status = serial_in(info, UART_LSR);
        restore_flags(flags);
        result = ((status & UART_LSR_TEMT) ? TIOCSER_TEMT : 0);
        return put_user(result,value);
}


static int
get_modem_info(struct su_struct * info, unsigned int *value)
{
        unsigned char control, status;
        unsigned int result;
        unsigned long flags;

        control = info->MCR;
        save_flags(flags); cli();
        status = serial_in(info, UART_MSR);
        restore_flags(flags);
        result =  ((control & UART_MCR_RTS) ? TIOCM_RTS : 0)
                | ((control & UART_MCR_DTR) ? TIOCM_DTR : 0)
#ifdef TIOCM_OUT1
                | ((control & UART_MCR_OUT1) ? TIOCM_OUT1 : 0)
                | ((control & UART_MCR_OUT2) ? TIOCM_OUT2 : 0)
#endif
                | ((status  & UART_MSR_DCD) ? TIOCM_CAR : 0)
                | ((status  & UART_MSR_RI) ? TIOCM_RNG : 0)
                | ((status  & UART_MSR_DSR) ? TIOCM_DSR : 0)
                | ((status  & UART_MSR_CTS) ? TIOCM_CTS : 0);
        return put_user(result,value);
}

static int
set_modem_info(struct su_struct * info, unsigned int cmd, unsigned int *value)
{
        int error;
        unsigned int arg;
        unsigned long flags;

        error = get_user(arg, value);
        if (error)
                return error;
        switch (cmd) {
        case TIOCMBIS: 
                if (arg & TIOCM_RTS)
                        info->MCR |= UART_MCR_RTS;
                if (arg & TIOCM_DTR)
                        info->MCR |= UART_MCR_DTR;
#ifdef TIOCM_OUT1
                if (arg & TIOCM_OUT1)
                        info->MCR |= UART_MCR_OUT1;
                if (arg & TIOCM_OUT2)
                        info->MCR |= UART_MCR_OUT2;
#endif
                break;
        case TIOCMBIC:
                if (arg & TIOCM_RTS)
                        info->MCR &= ~UART_MCR_RTS;
                if (arg & TIOCM_DTR)
                        info->MCR &= ~UART_MCR_DTR;
#ifdef TIOCM_OUT1
                if (arg & TIOCM_OUT1)
                        info->MCR &= ~UART_MCR_OUT1;
                if (arg & TIOCM_OUT2)
                        info->MCR &= ~UART_MCR_OUT2;
#endif
                break;
        case TIOCMSET:
                info->MCR = ((info->MCR & ~(UART_MCR_RTS |
#ifdef TIOCM_OUT1
                                            UART_MCR_OUT1 |
                                            UART_MCR_OUT2 |
#endif
                                            UART_MCR_DTR))
                             | ((arg & TIOCM_RTS) ? UART_MCR_RTS : 0)
#ifdef TIOCM_OUT1
                             | ((arg & TIOCM_OUT1) ? UART_MCR_OUT1 : 0)
                             | ((arg & TIOCM_OUT2) ? UART_MCR_OUT2 : 0)
#endif
                             | ((arg & TIOCM_DTR) ? UART_MCR_DTR : 0));
                break;
        default:
                return -EINVAL;
        }
        save_flags(flags); cli();
        serial_out(info, UART_MCR, info->MCR);
        restore_flags(flags);
        return 0;
}

/*
 * su_break() --- routine which turns the break handling on or off
 */
static void
su_break(struct tty_struct *tty, int break_state)
{
        struct su_struct * info = (struct su_struct *)tty->driver_data;
        unsigned long flags;
        
        if (serial_paranoia_check(info, tty->device, "su_break"))
                return;

        if (!info->port)
                return;
        save_flags(flags); cli();
        if (break_state == -1)
                serial_out(info, UART_LCR,
                           serial_inp(info, UART_LCR) | UART_LCR_SBC);
        else
                serial_out(info, UART_LCR,
                           serial_inp(info, UART_LCR) & ~UART_LCR_SBC);
        restore_flags(flags);
}

static int
su_ioctl(struct tty_struct *tty, struct file * file,
                    unsigned int cmd, unsigned long arg)
{
        int error;
        struct su_struct * info = (struct su_struct *)tty->driver_data;
        struct async_icount cprev, cnow;        /* kernel counter temps */
        struct serial_icounter_struct *p_cuser; /* user space */

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

        if ((cmd != TIOCGSERIAL) && (cmd != TIOCSSERIAL) &&
            (cmd != TIOCSERCONFIG) && (cmd != TIOCSERGSTRUCT) &&
            (cmd != TIOCMIWAIT) && (cmd != TIOCGICOUNT)) {
                if (tty->flags & (1 << TTY_IO_ERROR))
                    return -EIO;
        }

        switch (cmd) {
                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 TIOCSERGETLSR: /* Get line status register */
                        return get_lsr_info(info, (unsigned int *) arg);

#if 0
                case TIOCSERGSTRUCT:
                        if (copy_to_user((struct async_struct *) arg,
                                         info, sizeof(struct async_struct)))
                                return -EFAULT;
                        return 0;
#endif
                                
                /*
                 * Wait for any of the 4 modem inputs (DCD,RI,DSR,CTS) to change
                 * - mask passed in arg for lines of interest
                 *   (use |'ed TIOCM_RNG/DSR/CD/CTS for masking)
                 * Caller should use TIOCGICOUNT to see which one it was
                 */
                case TIOCMIWAIT:
                        cli();
                        /* note the counters on entry */
                        cprev = info->icount;
                        sti();
                        while (1) {
                                interruptible_sleep_on(&info->delta_msr_wait);
                                /* see if a signal did it */
                                if (signal_pending(current))
                                        return -ERESTARTSYS;
                                cli();
                                cnow = info->icount; /* atomic copy */
                                sti();
                                if (cnow.rng == cprev.rng && cnow.dsr == cprev.dsr && 
                                    cnow.dcd == cprev.dcd && cnow.cts == cprev.cts)
                                        return -EIO; /* no change => error */
                                if ( ((arg & TIOCM_RNG) && (cnow.rng != cprev.rng)) ||
                                     ((arg & TIOCM_DSR) && (cnow.dsr != cprev.dsr)) ||
                                     ((arg & TIOCM_CD)  && (cnow.dcd != cprev.dcd)) ||
                                     ((arg & TIOCM_CTS) && (cnow.cts != cprev.cts)) ) {
                                        return 0;
                                }
                                cprev = cnow;
                        }
                        /* NOTREACHED */

                /* 
                 * Get counter of input serial line interrupts (DCD,RI,DSR,CTS)
                 * Return: write counters to the user passed counter struct
                 * NB: both 1->0 and 0->1 transitions are counted except for
                 *     RI where only 0->1 is counted.
                 */
                case TIOCGICOUNT:
                        cli();
                        cnow = info->icount;
                        sti();
                        p_cuser = (struct serial_icounter_struct *) arg;
                        error = put_user(cnow.cts, &p_cuser->cts);
                        if (error) return error;
                        error = put_user(cnow.dsr, &p_cuser->dsr);
                        if (error) return error;
                        error = put_user(cnow.rng, &p_cuser->rng);
                        if (error) return error;
                        error = put_user(cnow.dcd, &p_cuser->dcd);
                        if (error) return error;
                        return 0;

                default:
                        return -ENOIOCTLCMD;
                }
        /* return 0; */ /* Trigger warnings if fall through by a chance. */
}

static void
su_set_termios(struct tty_struct *tty, struct termios *old_termios)
{
        struct su_struct *info = (struct su_struct *)tty->driver_data;
        unsigned long flags;

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

        change_speed(info, old_termios);

        /* Handle transition to B0 status */
        if ((old_termios->c_cflag & CBAUD) &&
            !(tty->termios->c_cflag & CBAUD)) {
                info->MCR &= ~(UART_MCR_DTR|UART_MCR_RTS);
                save_flags(flags); cli();
                serial_out(info, UART_MCR, info->MCR);
                restore_flags(flags);
        }

        /* Handle transition away from B0 status */
        if (!(old_termios->c_cflag & CBAUD) &&
            (tty->termios->c_cflag & CBAUD)) {
                info->MCR |= UART_MCR_DTR;
                if (!(tty->termios->c_cflag & CRTSCTS) || 
                    !test_bit(TTY_THROTTLED, &tty->flags)) {
                        info->MCR |= UART_MCR_RTS;
                }
                save_flags(flags); cli();
                serial_out(info, UART_MCR, info->MCR);
                restore_flags(flags);
        }
        
        /* Handle turning off CRTSCTS */
        if ((old_termios->c_cflag & CRTSCTS) &&
            !(tty->termios->c_cflag & CRTSCTS)) {
                tty->hw_stopped = 0;
                su_start(tty);
        }

#if 0
        /*
         * No need to wake up processes in open wait, since they
         * sample the CLOCAL flag once, and don't recheck it.
         * XXX  It's not clear whether the current behavior is correct
         * or not.  Hence, this may change.....
         */
        if (!(old_termios->c_cflag & CLOCAL) &&
            (tty->termios->c_cflag & CLOCAL))
                wake_up_interruptible(&info->open_wait);
#endif
}

/*
 * ------------------------------------------------------------
 * su_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
 * async structure from the interrupt chain if necessary, and we free
 * that IRQ if nothing is left in the chain.
 * ------------------------------------------------------------
 */
static void
su_close(struct tty_struct *tty, struct file * filp)
{
        struct su_struct *info = (struct su_struct *)tty->driver_data;
        unsigned long flags;

        if (!info || serial_paranoia_check(info, tty->device, "su_close"))
                return;

        save_flags(flags); cli();
        
        if (tty_hung_up_p(filp)) {
                DBG_CNT("before DEC-hung");
                MOD_DEC_USE_COUNT;
                restore_flags(flags);
                return;
        }
        
#ifdef SERIAL_DEBUG_OPEN
        printk("su_close ttys%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("su_close: bad serial port count; tty->count is 1, "
                       "info->count is %d\n", info->count);
                info->count = 1;
        }
        if (--info->count < 0) {
                printk("su_close: bad serial port count for ttys%d: %d\n",
                       info->line, info->count);
                info->count = 0;
        }
        if (info->count) {
                DBG_CNT("before DEC-2");
                MOD_DEC_USE_COUNT;
                restore_flags(flags);
                return;
        }
        info->flags |= ASYNC_CLOSING;
        /*
         * Save the termios structure, since this port may have
         * separate termios for callout and dialin.
         */
        if (info->flags & ASYNC_NORMAL_ACTIVE)
                info->normal_termios = *tty->termios;
        if (info->flags & ASYNC_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 != ASYNC_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.
         */
        info->IER &= ~UART_IER_RLSI;
        info->read_status_mask &= ~UART_LSR_DR;
        if (info->flags & ASYNC_INITIALIZED) {
                serial_out(info, UART_IER, info->IER);
                /*
                 * Before we drop DTR, make sure the UART transmitter
                 * has completely drained; this is especially
                 * important if there is a transmit FIFO!
                 */
                su_wait_until_sent(tty, info->timeout);
        }
        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 (info->blocked_open) {
                if (info->close_delay) {
                        current->state = TASK_INTERRUPTIBLE;
                        schedule_timeout(info->close_delay);
                }
                wake_up_interruptible(&info->open_wait);
        }
        info->flags &= ~(ASYNC_NORMAL_ACTIVE|ASYNC_CALLOUT_ACTIVE|
                         ASYNC_CLOSING);
        wake_up_interruptible(&info->close_wait);
        MOD_DEC_USE_COUNT;
        restore_flags(flags);
}

/*
 * su_wait_until_sent() --- wait until the transmitter is empty
 */
static void
su_wait_until_sent(struct tty_struct *tty, int timeout)
{
        struct su_struct * info = (struct su_struct *)tty->driver_data;
        unsigned long orig_jiffies, char_time;
        int lsr;

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

        if (info->type == PORT_UNKNOWN)
                return;

        if (info->xmit_fifo_size == 0)
                return; /* Just in case ... */

        orig_jiffies = jiffies;
        /*
         * Set the check interval to be 1/5 of the estimated time to
         * send a single character, and make it at least 1.  The check
         * interval should also be less than the timeout.
         * 
         * Note: we have to use pretty tight timings here to satisfy
         * the NIST-PCTS.
         */
        char_time = (info->timeout - HZ/50) / info->xmit_fifo_size;
        char_time = char_time / 5;
        if (char_time == 0)
                char_time = 1;
        if (timeout)
          char_time = MIN(char_time, timeout);
#ifdef SERIAL_DEBUG_RS_WAIT_UNTIL_SENT
        printk("In su_wait_until_sent(%d) check=%lu...", timeout, char_time);
        printk("jiff=%lu...", jiffies);
#endif
        while (!((lsr = serial_inp(info, UART_LSR)) & UART_LSR_TEMT)) {
#ifdef SERIAL_DEBUG_RS_WAIT_UNTIL_SENT
                printk("lsr = %d (jiff=%lu)...", lsr, jiffies);
#endif
                current->state = TASK_INTERRUPTIBLE;
                schedule_timeout(char_time);
                if (signal_pending(current))
                        break;
                if (timeout && time_after(jiffies, orig_jiffies + timeout))
                        break;
        }
#ifdef SERIAL_DEBUG_RS_WAIT_UNTIL_SENT
        printk("lsr = %d (jiff=%lu)...done\n", lsr, jiffies);
#endif
}

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

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

        su_flush_buffer(tty);
        shutdown(info);
        info->event = 0;
        info->count = 0;
        info->flags &= ~(ASYNC_NORMAL_ACTIVE|ASYNC_CALLOUT_ACTIVE);
        info->tty = 0;
        wake_up_interruptible(&info->open_wait);
}

/*
 * ------------------------------------------------------------
 * su_open() and friends
 * ------------------------------------------------------------
 */
static int
block_til_ready(struct tty_struct *tty, struct file * filp,
                struct su_struct *info)
{
        DECLARE_WAITQUEUE(wait, current);
        int               retval;
        int               do_clocal = 0, extra_count = 0;
        unsigned long     flags;

        /*
         * If the device is in the middle of being closed, then block
         * until it's done, and then try again.
         */
        if (tty_hung_up_p(filp) ||
            (info->flags & ASYNC_CLOSING)) {
                if (info->flags & ASYNC_CLOSING)
                        interruptible_sleep_on(&info->close_wait);
#ifdef SERIAL_DO_RESTART
                return ((info->flags & ASYNC_HUP_NOTIFY) ?
                        -EAGAIN : -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 & ASYNC_NORMAL_ACTIVE)
                        return -EBUSY;
                if ((info->flags & ASYNC_CALLOUT_ACTIVE) &&
                    (info->flags & ASYNC_SESSION_LOCKOUT) &&
                    (info->session != current->session))
                    return -EBUSY;
                if ((info->flags & ASYNC_CALLOUT_ACTIVE) &&
                    (info->flags & ASYNC_PGRP_LOCKOUT) &&
                    (info->pgrp != current->pgrp))
                    return -EBUSY;
                info->flags |= ASYNC_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 & ASYNC_CALLOUT_ACTIVE)
                        return -EBUSY;
                info->flags |= ASYNC_NORMAL_ACTIVE;
                return 0;
        }

        if (info->flags & ASYNC_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
         * su_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
        save_flags(flags); cli();
        if (!tty_hung_up_p(filp)) {
                extra_count = 1;
                info->count--;
        }
        restore_flags(flags);
        info->blocked_open++;
        while (1) {
                save_flags(flags); cli();
                if (!(info->flags & ASYNC_CALLOUT_ACTIVE) &&
                    (tty->termios->c_cflag & CBAUD))
                        serial_out(info, UART_MCR,
                                   serial_inp(info, UART_MCR) |
                                   (UART_MCR_DTR | UART_MCR_RTS));
                restore_flags(flags);
                set_current_state(TASK_INTERRUPTIBLE);
                if (tty_hung_up_p(filp) ||
                    !(info->flags & ASYNC_INITIALIZED)) {
#ifdef SERIAL_DO_RESTART
                        if (info->flags & ASYNC_HUP_NOTIFY)
                                retval = -EAGAIN;
                        else
                                retval = -ERESTARTSYS;  
#else
                        retval = -EAGAIN;
#endif
                        break;
                }
                if (!(info->flags & ASYNC_CALLOUT_ACTIVE) &&
                    !(info->flags & ASYNC_CLOSING) &&
                    (do_clocal || (serial_in(info, UART_MSR) &
                                   UART_MSR_DCD)))
                        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 (extra_count)
                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 |= ASYNC_NORMAL_ACTIVE;
        return 0;
}

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

        line = MINOR(tty->device) - tty->driver.minor_start;
        if ((line < 0) || (line >= NR_PORTS))
                return -ENODEV;
        info = su_table + line;
        info->count++;
        tty->driver_data = info;
        info->tty = tty;

        if (serial_paranoia_check(info, tty->device, "su_open")) {
                info->count--;
                return -ENODEV;
        }

#ifdef SERIAL_DEBUG_OPEN
        printk("su_open %s%d, count = %d\n", tty->driver.name, info->line,
               info->count);
#endif
        info->tty->low_latency = (info->flags & ASYNC_LOW_LATENCY) ? 1 : 0;

        if (!tmp_buf) {
                page = get_free_page(GFP_KERNEL);
                if (!page)
                        return -ENOMEM;
                if (tmp_buf)
                        free_page(page);
                else
                        tmp_buf = (unsigned char *) page;
        }

        /*
         * If the port is the middle of closing, bail out now
         */
        if (tty_hung_up_p(filp) ||
            (info->flags & ASYNC_CLOSING)) {
                if (info->flags & ASYNC_CLOSING)
                        interruptible_sleep_on(&info->close_wait);
#ifdef SERIAL_DO_RESTART
                return ((info->flags & ASYNC_HUP_NOTIFY) ?
                        -EAGAIN : -ERESTARTSYS);
#else
                return -EAGAIN;
#endif
        }
        
        /*
         * Start up serial port
         */
        retval = startup(info);
        if (retval)
                return retval;

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

        if ((info->count == 1) &&
            (info->flags & ASYNC_SPLIT_TERMIOS)) {
                if (tty->driver.subtype == SERIAL_TYPE_NORMAL)
                        *tty->termios = info->normal_termios;
                else 
                        *tty->termios = info->callout_termios;
                change_speed(info, 0);
        }
#ifdef CONFIG_SERIAL_CONSOLE
        if (sercons.cflag && sercons.index == line) {
                tty->termios->c_cflag = sercons.cflag;
                sercons.cflag = 0;
                change_speed(info, 0);
        }
#endif
        info->session = current->session;
        info->pgrp = current->pgrp;

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

/*
 * /proc fs routines....
 */
static __inline__ int
line_info(char *buf, struct su_struct *info)
{
        char            stat_buf[30], control, status;
        int             ret;
        unsigned long   flags;

        if (info->port == 0 || info->type == PORT_UNKNOWN)
                return 0;

        ret = sprintf(buf, "%u: uart:%s port:%lX irq:%s",
                      info->line, uart_config[info->type].name, 
                      (unsigned long)info->port, __irq_itoa(info->irq));

        /*
         * Figure out the current RS-232 lines
         */
        save_flags(flags); cli();
        status = serial_in(info, UART_MSR);
        control = info ? info->MCR : serial_in(info, UART_MCR);
        restore_flags(flags);

        stat_buf[0] = 0;
        stat_buf[1] = 0;
        if (control & UART_MCR_RTS)
                strcat(stat_buf, "|RTS");
        if (status & UART_MSR_CTS)
                strcat(stat_buf, "|CTS");
        if (control & UART_MCR_DTR)
                strcat(stat_buf, "|DTR");
        if (status & UART_MSR_DSR)
                strcat(stat_buf, "|DSR");
        if (status & UART_MSR_DCD)
                strcat(stat_buf, "|CD");
        if (status & UART_MSR_RI)
                strcat(stat_buf, "|RI");

        if (info->quot) {
                ret += sprintf(buf+ret, " baud:%u",
                               info->baud_base / info->quot);
        }

        ret += sprintf(buf+ret, " tx:%u rx:%u",
                       info->icount.tx, info->icount.rx);

        if (info->icount.frame)
                ret += sprintf(buf+ret, " fe:%u", info->icount.frame);

        if (info->icount.parity)
                ret += sprintf(buf+ret, " pe:%u", info->icount.parity);

        if (info->icount.brk)
                ret += sprintf(buf+ret, " brk:%u", info->icount.brk);   

        if (info->icount.overrun)
                ret += sprintf(buf+ret, " oe:%u", info->icount.overrun);

        /*
         * Last thing is the RS-232 status lines
         */
        ret += sprintf(buf+ret, " %s\n", stat_buf+1);
        return ret;
}

int su_read_proc(char *page, char **start, off_t off, int count,
                 int *eof, void *data)
{
        int i, len = 0;
        off_t   begin = 0;

        len += sprintf(page, "serinfo:1.0 driver:%s\n", serial_version);
        for (i = 0; i < NR_PORTS && len < 4000; i++) {
                len += line_info(page + len, &su_table[i]);
                if (len+begin > off+count)
                        goto done;
                if (len+begin < off) {
                        begin += len;
                        len = 0;
                }
        }
        *eof = 1;
done:
        if (off >= len+begin)
                return 0;
        *start = page + (off-begin);
        return ((count < begin+len-off) ? count : begin+len-off);
}

/*
 * ---------------------------------------------------------------------
 * su_XXX_init() and friends
 *
 * su_XXX_init() is called at boot-time to initialize the serial driver.
 * ---------------------------------------------------------------------
 */

/*
 * This routine prints out the appropriate serial driver version
 * number, and identifies which options were configured into this
 * driver.
 */
static __inline__ void __init show_su_version(void)
{
        char *revision = "$Revision: 1.43 $";
        char *version, *p;

        version = strchr(revision, ' ');
        strcpy(serial_version, ++version);
        p = strchr(serial_version, ' ');
        *p = '\0';
        printk(KERN_INFO "%s version %s\n", serial_name, serial_version);
}

/*
 * This routine is called by su_{serial|kbd_ms}_init() to initialize a specific
 * serial port.  It determines what type of UART chip this serial port is
 * using: 8250, 16450, 16550, 16550A.  The important question is
 * whether or not this UART is a 16550A, since this will determine
 * whether or not we can use its FIFO features.
 */
static void
autoconfig(struct su_struct *info)
{
        unsigned char status1, status2, scratch, scratch2;
        struct linux_ebus_device *dev = 0;
        struct linux_ebus *ebus;
#ifndef __sparc_v9__
        struct linux_prom_registers reg0;
#endif
        unsigned long flags;

        if (!info->port_node || !info->port_type)
                return;

        /*
         * First we look for Ebus-bases su's
         */
        for_each_ebus(ebus) {
                for_each_ebusdev(dev, ebus) {
                        if (dev->prom_node == info->port_node) {
                                info->port = dev->resource[0].start;
                                info->irq = dev->irqs[0];
                                goto ebus_done;
                        }
                }
        }

#ifdef __sparc_v9__
        /*
         * Not on Ebus, bailing.
         */
        return;
#else
        /*
         * Not on Ebus, must be OBIO.
         */
        if (prom_getproperty(info->port_node, "reg",
            (char *)&reg0, sizeof(reg0)) == -1) {
                prom_printf("su: no \"reg\" property\n");
                return;
        }
        prom_apply_obio_ranges(&reg0, 1);
        if (reg0.which_io != 0) {       /* Just in case... */
                prom_printf("su: bus number nonzero: 0x%x:%x\n",
                    reg0.which_io, reg0.phys_addr);
                return;
        }
        if ((info->port = (unsigned long) ioremap(reg0.phys_addr,
            reg0.reg_size)) == 0) {
                prom_printf("su: cannot map\n");
                return;
        }

        /*
         * There is no intr property on MrCoffee, so hardwire it.
         */
        info->irq = IRQ_4M(13);
#endif

ebus_done:

#ifdef SERIAL_DEBUG_OPEN
        printk("Found 'su' at %016lx IRQ %s\n", info->port,
                __irq_itoa(info->irq));
#endif

        info->magic = SERIAL_MAGIC;

        save_flags(flags); cli();

        /*
         * Do a simple existence test first; if we fail this, there's
         * no point trying anything else.
         *
         * 0x80 is used as a nonsense port to prevent against false
         * positives due to ISA bus float.  The assumption is that
         * 0x80 is a non-existent port; which should be safe since
         * include/asm/io.h also makes this assumption.
         */
        scratch = serial_inp(info, UART_IER);
        serial_outp(info, UART_IER, 0);
        scratch2 = serial_inp(info, UART_IER);
        serial_outp(info, UART_IER, scratch);
        if (scratch2) {
                restore_flags(flags);
                return;         /* We failed; there's nothing here */
        }

        scratch = serial_inp(info, UART_MCR);
        serial_outp(info, UART_MCR, UART_MCR_LOOP | scratch);
        serial_outp(info, UART_MCR, UART_MCR_LOOP | 0x0A);
        status1 = serial_inp(info, UART_MSR) & 0xF0;
        serial_outp(info, UART_MCR, scratch);
        if (status1 != 0x90) {
                /*
                 * This code fragment used to fail, now it fixed itself.
                 * We keep the printout for a case.
                 */
                printk("su: loopback returned status 0x%02x\n", status1);
                restore_flags(flags);
                return;
        } 

        scratch2 = serial_in(info, UART_LCR);
        serial_outp(info, UART_LCR, 0xBF);      /* set up for StarTech test */
        serial_outp(info, UART_EFR, 0);         /* EFR is the same as FCR */
        serial_outp(info, UART_LCR, 0);
        serial_outp(info, UART_FCR, UART_FCR_ENABLE_FIFO);
        scratch = serial_in(info, UART_IIR) >> 6;
        switch (scratch) {
                case 0:
                        info->type = PORT_16450;
                        break;
                case 1:
                        info->type = PORT_UNKNOWN;
                        break;
                case 2:
                        info->type = PORT_16550;
                        break;
                case 3:
                        info->type = PORT_16550A;
                        break;
        }
        if (info->type == PORT_16550A) {
                /* Check for Startech UART's */
                serial_outp(info, UART_LCR, scratch2 | UART_LCR_DLAB);
                if (serial_in(info, UART_EFR) == 0) {
                        info->type = PORT_16650;
                } else {
                        serial_outp(info, UART_LCR, 0xBF);
                        if (serial_in(info, UART_EFR) == 0)
                                info->type = PORT_16650V2;
                }
        }
        if (info->type == PORT_16550A) {
                /* Check for TI 16750 */
                serial_outp(info, UART_LCR, scratch2 | UART_LCR_DLAB);
                serial_outp(info, UART_FCR,
                            UART_FCR_ENABLE_FIFO | UART_FCR7_64BYTE);
                scratch = serial_in(info, UART_IIR) >> 5;
                if (scratch == 7) {
                        serial_outp(info, UART_LCR, 0);
                        serial_outp(info, UART_FCR, UART_FCR_ENABLE_FIFO);
                        scratch = serial_in(info, UART_IIR) >> 5;
                        if (scratch == 6)
                                info->type = PORT_16750;
                }
                serial_outp(info, UART_FCR, UART_FCR_ENABLE_FIFO);
        }
        serial_outp(info, UART_LCR, scratch2);
        if (info->type == PORT_16450) {
                scratch = serial_in(info, UART_SCR);
                serial_outp(info, UART_SCR, 0xa5);
                status1 = serial_in(info, UART_SCR);
                serial_outp(info, UART_SCR, 0x5a);
                status2 = serial_in(info, UART_SCR);
                serial_outp(info, UART_SCR, scratch);

                if ((status1 != 0xa5) || (status2 != 0x5a))
                        info->type = PORT_8250;
        }
        info->xmit_fifo_size = uart_config[info->type].dfl_xmit_fifo_size;

        if (info->type == PORT_UNKNOWN) {
                restore_flags(flags);
                return;
        }

        sprintf(info->name, "su(%s)", su_typev[info->port_type]);

        /*
         * Reset the UART.
         */
        serial_outp(info, UART_MCR, 0x00);
        serial_outp(info, UART_FCR, (UART_FCR_CLEAR_RCVR|UART_FCR_CLEAR_XMIT));
        (void)serial_in(info, UART_RX);
        serial_outp(info, UART_IER, 0x00);

        restore_flags(flags);
}

/* This is used by the SAB driver to adjust where its minor
 * numbers start, we always are probed for first.
 */
int su_num_ports = 0;
EXPORT_SYMBOL(su_num_ports);

/*
 * The serial driver boot-time initialization code!
 */
int __init su_serial_init(void)
{
        int i;
        struct su_struct *info;

        init_bh(SERIAL_BH, do_serial_bh);
        show_su_version();

        /* Initialize the tty_driver structure */

        memset(&serial_driver, 0, sizeof(struct tty_driver));
        serial_driver.magic = TTY_DRIVER_MAGIC;
        serial_driver.driver_name = "su";
#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 = NR_PORTS;
        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 = su_open;
        serial_driver.close = su_close;
        serial_driver.write = su_write;
        serial_driver.put_char = su_put_char;
        serial_driver.flush_chars = su_flush_chars;
        serial_driver.write_room = su_write_room;
        serial_driver.chars_in_buffer = su_chars_in_buffer;
        serial_driver.flush_buffer = su_flush_buffer;
        serial_driver.ioctl = su_ioctl;
        serial_driver.throttle = su_throttle;
        serial_driver.unthrottle = su_unthrottle;
        serial_driver.send_xchar = su_send_xchar;
        serial_driver.set_termios = su_set_termios;
        serial_driver.stop = su_stop;
        serial_driver.start = su_start;
        serial_driver.hangup = su_hangup;
        serial_driver.break_ctl = su_break;
        serial_driver.wait_until_sent = su_wait_until_sent;
        serial_driver.read_proc = su_read_proc;

        /*
         * The callout device is just like normal device except for
         * major number and the subtype code.
         */
        callout_driver = serial_driver;
#ifdef CONFIG_DEVFS_FS
        callout_driver.name = "cua/%d";
#else
        callout_driver.name = "cua";
#endif
        callout_driver.major = TTYAUX_MAJOR;
        callout_driver.subtype = SERIAL_TYPE_CALLOUT;
        callout_driver.read_proc = 0;
        callout_driver.proc_entry = 0;

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

        for (i = 0, info = su_table; i < NR_PORTS; i++, info++) {
                info->line = i;
                info->type = PORT_UNKNOWN;
                info->baud_base = BAUD_BASE;
                /* info->flags = 0; */
                info->custom_divisor = 0;
                info->close_delay = 5*HZ/10;
                info->closing_wait = 30*HZ;
                info->callout_termios = callout_driver.init_termios;
                info->normal_termios = serial_driver.init_termios;
                info->icount.cts = info->icount.dsr = 
                        info->icount.rng = info->icount.dcd = 0;
                info->icount.rx = info->icount.tx = 0;
                info->icount.frame = info->icount.parity = 0;
                info->icount.overrun = info->icount.brk = 0;
                info->tqueue.routine = do_softint;
                info->tqueue.data = info;
                info->cflag = serial_driver.init_termios.c_cflag;
                init_waitqueue_head(&info->open_wait);
                init_waitqueue_head(&info->close_wait);
                init_waitqueue_head(&info->delta_msr_wait);

                autoconfig(info);
                if (info->type == PORT_UNKNOWN)
                        continue;

                printk(KERN_INFO "%s at 0x%lx (tty %d irq %s) is a %s\n",
                       info->name, (long)info->port, i, __irq_itoa(info->irq),
                       uart_config[info->type].name);
        }

        for (i = 0, info = su_table; i < NR_PORTS; i++, info++)
                if (info->type == PORT_UNKNOWN)
                        break;

        su_num_ports = i;
        serial_driver.num = callout_driver.num = i;

        return 0;
}

int __init su_kbd_ms_init(void)
{
        int i;
        struct su_struct *info;

        show_su_version();

        for (i = 0, info = su_table; i < 2; i++, info++) {
                info->line = i;
                info->type = PORT_UNKNOWN;
                info->baud_base = BAUD_BASE;

                if (info->port_type == SU_PORT_KBD)
                        info->cflag = B1200 | CS8 | CLOCAL | CREAD;
                else
                        info->cflag = B4800 | CS8 | CLOCAL | CREAD;

                init_waitqueue_head(&info->open_wait);
                init_waitqueue_head(&info->close_wait);
                init_waitqueue_head(&info->delta_msr_wait);

                autoconfig(info);
                if (info->type == PORT_UNKNOWN)
                        continue;

                printk(KERN_INFO "%s at 0x%lx (irq = %s) is a %s\n",
                       info->name, info->port, __irq_itoa(info->irq),
                       uart_config[info->type].name);

                startup(info);
                if (info->port_type == SU_PORT_KBD)
                        keyboard_zsinit(su_put_char_kbd);
                else
                        sun_mouse_zsinit();
        }
        return 0;
}

/*
 * We got several platforms which present 'su' in different parts
 * of device tree. 'su' may be found under obio, ebus, isa and pci.
 * We walk over the tree and find them wherever PROM hides them.
 */
void __init su_probe_any(struct su_probe_scan *t, int sunode)
{
        struct su_struct *info;
        int len;

        if (t->devices >= NR_PORTS) return;

        for (; sunode != 0; sunode = prom_getsibling(sunode)) {
                len = prom_getproperty(sunode, "name", t->prop, SU_PROPSIZE);
                if (len <= 1) continue;         /* Broken PROM node */
                if (strncmp(t->prop, "su", len) == 0 ||
                    strncmp(t->prop, "serial", len) == 0 ||
                    strncmp(t->prop, "su_pnp", len) == 0) {
                        info = &su_table[t->devices];
                        if (t->kbnode != 0 && sunode == t->kbnode) {
                                t->kbx = t->devices;
                                info->port_type = SU_PORT_KBD;
                        } else if (t->msnode != 0 && sunode == t->msnode) {
                                t->msx = t->devices;
                                info->port_type = SU_PORT_MS;
                        } else {
#ifdef __sparc_v9__
                                /*
                                 * Do not attempt to use the truncated
                                 * keyboard/mouse ports as serial ports
                                 * on Ultras with PC keyboard attached.
                                 */
                                if (prom_getbool(sunode, "mouse"))
                                        continue;
                                if (prom_getbool(sunode, "keyboard"))
                                        continue;
#endif
                                info->port_type = SU_PORT_PORT;
                        }
                        info->is_console = 0;
                        info->port_node = sunode;
                        ++t->devices;
                } else {
                        su_probe_any(t, prom_getchild(sunode));
                }
        }
}

int __init su_probe(void)
{
        int node;
        int len;
        struct su_probe_scan scan;

        /*
         * First, we scan the tree.
         */
        scan.devices = 0;
        scan.msx = -1;
        scan.kbx = -1;
        scan.kbnode = 0;
        scan.msnode = 0;

        /*
         * Get the nodes for keyboard and mouse from 'aliases'...
         */
        node = prom_getchild(prom_root_node);
        node = prom_searchsiblings(node, "aliases");
        if (node != 0) {

                len = prom_getproperty(node, "keyboard", scan.prop,SU_PROPSIZE);
                if (len > 0) {
                        scan.prop[len] = 0;
                        scan.kbnode = prom_finddevice(scan.prop);
                }

                len = prom_getproperty(node, "mouse", scan.prop, SU_PROPSIZE);
                if (len > 0) {
                        scan.prop[len] = 0;
                        scan.msnode = prom_finddevice(scan.prop);
                }
        }

        su_probe_any(&scan, prom_getchild(prom_root_node));

        /*
         * Second, we process the special case of keyboard and mouse.
         *
         * Currently if we got keyboard and mouse hooked to "su" ports
         * we do not use any possible remaining "su" as a serial port.
         * Thus, we ignore values of .msx and .kbx, then compact ports.
         * Those who want to address this issue need to merge
         * su_serial_init() and su_ms_kbd_init().
         */
        if (scan.msx != -1 && scan.kbx != -1) {
                su_table[0].port_type = SU_PORT_MS;
                su_table[0].is_console = 0;
                su_table[0].port_node = scan.msnode;
                su_table[1].port_type = SU_PORT_KBD;
                su_table[1].is_console = 0;
                su_table[1].port_node = scan.kbnode;

                sunserial_setinitfunc(su_kbd_ms_init);
                rs_ops.rs_change_mouse_baud = su_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;
#ifdef 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;
        }
        if (scan.msx != -1 || scan.kbx != -1) {
                printk("su_probe: cannot match keyboard and mouse, confused\n");
                return -ENODEV;
        }

        if (scan.devices == 0)
                return -ENODEV;

#ifdef CONFIG_SERIAL_CONSOLE
        /*
         * Console must be initiated after the generic initialization.
         * sunserial_setinitfunc inverts order, so call this before next one.
         */
        sunserial_setinitfunc(su_serial_console_init);
#endif
        sunserial_setinitfunc(su_serial_init);
        return 0;
}

/*
 * ------------------------------------------------------------
 * Serial console driver
 * ------------------------------------------------------------
 */
#ifdef CONFIG_SERIAL_CONSOLE

#define BOTH_EMPTY (UART_LSR_TEMT | UART_LSR_THRE)

/*
 *      Wait for transmitter & holding register to empty
 */
static __inline__ void
wait_for_xmitr(struct su_struct *info)
{
        int lsr;
        unsigned int tmout = 1000000;

        do {
                lsr = su_inb(info, UART_LSR);
                if (--tmout == 0)
                        break;
        } while ((lsr & BOTH_EMPTY) != BOTH_EMPTY);
}

/*
 *      Print a string to the serial port trying not to disturb
 *      any possible real use of the port...
 */
static void
serial_console_write(struct console *co, const char *s,
                                unsigned count)
{
        struct su_struct *info;
        int ier;
        unsigned i;

        info = su_table + co->index;
        /*
         *      First save the IER then disable the interrupts
         */
        ier = su_inb(info, UART_IER);
        su_outb(info, UART_IER, 0x00);

        /*
         *      Now, do each character
         */
        for (i = 0; i < count; i++, s++) {
                wait_for_xmitr(info);

                /*
                 *      Send the character out.
                 *      If a LF, also do CR...
                 */
                su_outb(info, UART_TX, *s);
                if (*s == 10) {
                        wait_for_xmitr(info);
                        su_outb(info, UART_TX, 13);
                }
        }

        /*
         *      Finally, Wait for transmitter & holding register to empty
         *      and restore the IER
         */
        wait_for_xmitr(info);
        su_outb(info, UART_IER, ier);
}

/*
 *      Receive character from the serial port
 */
static int
serial_console_wait_key(struct console *co)
{
        struct su_struct *info;
        int ier;
        int lsr;
        int c;

        info = su_table + co->index;

        /*
         *      First save the IER then disable the interrupts so
         *      that the real driver for the port does not get the
         *      character.
         */
        ier = su_inb(info, UART_IER);
        su_outb(info, UART_IER, 0x00);

        do {
                lsr = su_inb(info, UART_LSR);
        } while (!(lsr & UART_LSR_DR));
        c = su_inb(info, UART_RX);

        /*
         *      Restore the interrupts
         */
        su_outb(info, UART_IER, ier);

        return c;
}

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

/*
 *      Setup initial baud/bits/parity. We do two things here:
 *      - construct a cflag setting for the first su_open()
 *      - initialize the serial port
 *      Return non-zero if we didn't find a serial port.
 */
static int __init serial_console_setup(struct console *co, char *options)
{
        struct su_struct *info;
        unsigned cval;
        int     baud = 9600;
        int     bits = 8;
        int     parity = 'n';
        int     cflag = CREAD | HUPCL | CLOCAL;
        int     quot = 0;
        char    *s;

        if (options) {
                baud = simple_strtoul(options, NULL, 10);
                s = options;
                while(*s >= '0' && *s <= '9')
                        s++;
                if (*s) parity = *s++;
                if (*s) bits   = *s - '0';
        }

        /*
         *      Now construct a cflag setting.
         */
        switch(baud) {
                case 1200:
                        cflag |= B1200;
                        break;
                case 2400:
                        cflag |= B2400;
                        break;
                case 4800:
                        cflag |= B4800;
                        break;
                case 19200:
                        cflag |= B19200;
                        break;
                case 38400:
                        cflag |= B38400;
                        break;
                case 57600:
                        cflag |= B57600;
                        break;
                case 115200:
                        cflag |= B115200;
                        break;
                case 9600:
                default:
                        cflag |= B9600;
                        break;
        }
        switch(bits) {
                case 7:
                        cflag |= CS7;
                        break;
                default:
                case 8:
                        cflag |= CS8;
                        break;
        }
        switch(parity) {
                case 'o': case 'O':
                        cflag |= PARODD;
                        break;
                case 'e': case 'E':
                        cflag |= PARENB;
                        break;
        }
        co->cflag = cflag;

        /*
         *      Divisor, bytesize and parity
         */
        info = su_table + co->index;
        quot = BAUD_BASE / baud;
        cval = cflag & (CSIZE | CSTOPB);
#if defined(__powerpc__) || defined(__alpha__)
        cval >>= 8;
#else /* !__powerpc__ && !__alpha__ */
        cval >>= 4;
#endif /* !__powerpc__ && !__alpha__ */
        if (cflag & PARENB)
                cval |= UART_LCR_PARITY;
        if (!(cflag & PARODD))
                cval |= UART_LCR_EPAR;

        /*
         *      Disable UART interrupts, set DTR and RTS high
         *      and set speed.
         */
        su_outb(info, UART_IER, 0);
        su_outb(info, UART_MCR, UART_MCR_DTR | UART_MCR_RTS);
        su_outb(info, UART_LCR, cval | UART_LCR_DLAB);  /* set DLAB */
        su_outb(info, UART_DLL, quot & 0xff);           /* LS of divisor */
        su_outb(info, UART_DLM, quot >> 8);             /* MS of divisor */
        su_outb(info, UART_LCR, cval);                  /* reset DLAB */
        info->quot = quot;

        /*
         *      If we read 0xff from the LSR, there is no UART here.
         */
        if (su_inb(info, UART_LSR) == 0xff)
                return -1;

        info->is_console = 1;

        return 0;
}

static struct console sercons = {
        name:           "ttyS",
        write:          serial_console_write,
        device:         serial_console_device,
        wait_key:       serial_console_wait_key,
        setup:          serial_console_setup,
        flags:          CON_PRINTBUFFER,
        index:          -1,
};

int su_console_registered = 0;

/*
 *      Register console.
 */
int __init su_serial_console_init(void)
{
        extern int con_is_present(void);

        if (con_is_present())
                return 0;
        if (serial_console == 0)
                return 0;
        if (su_table[0].port == 0 || su_table[0].port_node == 0)
                return 0;
        sercons.index = 0;
        register_console(&sercons);
        su_console_registered = 1;
        return 0;
}

#endif /* CONFIG_SERIAL_CONSOLE */