# isdn_hybrid.c

    /*
     *  linux/drivers/char/serial.c
     *
     *  Copyright (C) 1991, 1992  Linus Torvalds
     *
     *  Extensively rewritten by Theodore Ts'o, 8/16/92 -- 9/14/92.  Now
     *  much more extensible to support other serial cards based on the
     *  16450/16550A UART's.  Added support for the AST FourPort and the
     *  Accent Async board.
     *
     *  set_serial_info fixed to set the flags, custom divisor, and uart
     * 	type fields.  Fix suggested by Michael K. Johnson 12/12/92.
     *
     *  11/95: TIOCMIWAIT, TIOCGICOUNT by Angelo Haritsis <ah@doc.ic.ac.uk>
     *
     *  03/96: Modularised by Angelo Haritsis <ah@doc.ic.ac.uk>
     *
     *  rs_set_termios fixed to look also for changes of the input
     *      flags INPCK, BRKINT, PARMRK, IGNPAR and IGNBRK.
     *                                            Bernd Anhäupl 05/17/96.
     *
     *  1/97:  Extended dumb serial ports are a config option now.
     *         Saves 4k.   Michael A. Griffith <grif@acm.org>
     *
     *  8/97: Fix bug in rs_set_termios with RTS
     *        Stanislav V. Voronyi <stas@uanet.kharkov.ua>
     *
     * This module exports the following rs232 io functions:
     *
     *	int rs_init(void);
     */

    #include <linux/config.h>
    #include <linux/module.h>
    #include <linux/errno.h>
    #include <linux/signal.h>
    #include <linux/sched.h>
    #include <linux/timer.h>
    #include <linux/interrupt.h>
    #include <linux/tty.h>
    #include <linux/tty_flip.h>
    #include <linux/serial.h>
    #include <linux/serial_reg.h>
    #include <linux/major.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 <asm/system.h>
    #include <asm/io.h>
    #include <asm/uaccess.h>
    #include <asm/bitops.h>

    static char *serial_name = "Serial driver";
    static char *serial_version = "4.24";

    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

    #define SERIAL_PARANOIA_CHECK
    #define CONFIG_SERIAL_NOPAUSE_IO
    #define SERIAL_DO_RESTART

    /* Sanity checks */

    /* Set of debugging defines */

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

    #define RS_STROBE_TIME (10*HZ)
    #define RS_ISR_PASS_LIMIT 256

    #define IRQ_T(info) ((info->flags & ASYNC_SHARE_IRQ) ? SA_SHIRQ : SA_INTERRUPT)

    #define _INLINE_ inline

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

    /*
     * IRQ_timeout		- How long the timeout should be for each IRQ
     * 				should be after the IRQ has been active.
     */

    static struct async_struct *IRQ_ports[16];
    static int IRQ_timeout[16];
    static volatile int rs_irq_triggered;
    static volatile int rs_triggered;
    static int rs_wild_int_mask;

    static void autoconfig(struct serial_state * info);
    static void change_speed(struct async_struct *info);
    static void rs_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}
    };

    /*
     * This assumes you have a 1.8432 MHz clock for your UART.
     *
     * It'd be nice if someone built a serial card with a 24.576 MHz
     * clock, since the 16550A is capable of handling a top speed of 1.5
     * megabits/second; but this requires the faster clock.
     */
    #define BASE_BAUD ( 1843200 / 16 )

    /* Standard COM flags (except for COM4, because of the 8514 problem) */
    #define STD_COM_FLAGS (ASYNC_BOOT_AUTOCONF | ASYNC_SKIP_TEST )
    #define STD_COM4_FLAGS ASYNC_BOOT_AUTOCONF

    #define C_P(card,port) (((card)<<6|(port)<<3) + 1)

    static struct serial_state rs_table[] = {
    	/* UART CLK   PORT IRQ     FLAGS        */
    	{ 0, BASE_BAUD, 0x3F8, 4, STD_COM_FLAGS },	/* ttyS0 */
    	{ 0, BASE_BAUD, 0x2F8, 3, STD_COM_FLAGS },	/* ttyS1 */
    	{ 0, BASE_BAUD, 0x3E8, 4, STD_COM_FLAGS },	/* ttyS2 */
    	{ 0, BASE_BAUD, 0x2E8, 3, STD_COM4_FLAGS },	/* ttyS3 */
    };

    #define NR_PORTS	(sizeof(rs_table)/sizeof(struct serial_state))

    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 = 0;
    static struct semaphore tmp_buf_sem = MUTEX;

    static inline int serial_paranoia_check(struct async_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 async_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 serial_in(struct async_struct *info, int offset)
    {
    	return inb(info->port + offset);
    }

    static inline unsigned int serial_inp(struct async_struct *info, int offset)
    {
    #ifdef CONFIG_SERIAL_NOPAUSE_IO
    	return inb(info->port + offset);
    #else
    	return inb_p(info->port + offset);
    #endif
    }

    static inline void serial_out(struct async_struct *info, int offset, int value)
    {
    	outb(value, info->port+offset);
    }

    static inline void serial_outp(struct async_struct *info, int offset,
    			       int value)
    {
    #ifdef CONFIG_SERIAL_NOPAUSE_IO
    	outb(value, info->port+offset);
    #else
        	outb_p(value, info->port+offset);
    #endif
    }

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

    	if (serial_paranoia_check(info, tty->device, "rs_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 rs_start(struct tty_struct *tty)
    {
    	struct async_struct *info = (struct async_struct *)tty->driver_data;
    	unsigned long flags;

    	if (serial_paranoia_check(info, tty->device, "rs_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
     * rs_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 rs_sched_event(struct async_struct *info,
    				  int event)
    {
    	info->event |= 1 << event;
    	queue_task(&info->tqueue, &tq_serial);
    	mark_bh(SERIAL_BH);
    }

    static _INLINE_ void receive_chars(struct async_struct *info,
    				 int *status)
    {
    	struct tty_struct *tty = info->tty;
    	unsigned char ch;
    	int ignored = 0;
    	struct	async_icount *icount;

    	icount = &info->state->icount;
    	do {
    		ch = serial_inp(info, UART_RX);
    		if (tty->flip.count >= TTY_FLIPBUF_SIZE)
    			break;
    		*tty->flip.char_buf_ptr = ch;
    		icount->rx++;

    #ifdef SERIAL_DEBUG_INTR
    		printk("DR%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)
    					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);
    	isdn_hybrid_flip_buffer_push(tty);
    }

    static _INLINE_ void transmit_chars(struct async_struct *info, int *intr_done)
    {
    	int count;

    	if (info->x_char) {
    		serial_outp(info, UART_TX, info->x_char);
    		info->state->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->state->icount.tx++;
    		if (--info->xmit_cnt <= 0)
    			break;
    	} while (--count > 0);

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

    #ifdef SERIAL_DEBUG_INTR
    	printk("THRE...");
    #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 async_struct *info)
    {
    	int	status;
    	struct	async_icount *icount;

    	status = serial_in(info, UART_MSR);

    	if (status & UART_MSR_ANY_DELTA) {
    		icount = &info->state->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);
    				rs_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 serial driver's interrupt routine for a single port
     */
    static void rs_interrupt_single(int irq, void *dev_id, struct pt_regs * regs)
    {
    	int status;
    	int pass_counter = 0;
    	struct async_struct * info;

    #ifdef SERIAL_DEBUG_INTR
    	printk("rs_interrupt_single(%d)...", irq);
    #endif

    	info = IRQ_ports[irq];
    	if (!info || !info->tty)
    		return;

    	do {
    		status = serial_inp(info, UART_LSR);
    #ifdef SERIAL_DEBUG_INTR
    		printk("status = %x...", status);
    #endif
    		if (status & UART_LSR_DR)
    			receive_chars(info, &status);
    		check_modem_status(info);
    		if (status & UART_LSR_THRE)
    			transmit_chars(info, 0);
    		if (pass_counter++ > RS_ISR_PASS_LIMIT) {
    #if 0
    			printk("rs_single loop break.\n");
    #endif
    			break;
    		}
    	} 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
     * rs_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 rs_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 async_struct	*info = (struct async_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);
    	}
    }

    /*
     * This subroutine is called when the RS_TIMER goes off.  It is used
     * by the serial driver to handle ports that do not have an interrupt
     * (irq=0).  This doesn't work very well for 16450's, but gives barely
     * passable results for a 16550A.  (Although at the expense of much
     * CPU overhead).
     */
    static void rs_timer(void)
    {
    	static unsigned long last_strobe = 0;
    	struct async_struct *info;
    	unsigned int	i;

    	if ((jiffies - last_strobe) >= RS_STROBE_TIME) {
    		for (i=1; i < 16; i++) {
    			info = IRQ_ports[i];
    			if (!info)
    				continue;
    			cli();
    #ifdef CONFIG_SERIAL_SHARE_IRQ
    			if (info->next_port) {
    				do {
    					serial_out(info, UART_IER, 0);
    					info->IER |= UART_IER_THRI;
    					serial_out(info, UART_IER, info->IER);
    					info = info->next_port;
    				} while (info);
    #ifdef CONFIG_SERIAL_MULTIPORT
    				if (rs_multiport[i].port1)
    					rs_interrupt_multi(i, NULL, NULL);
    				else
    #endif
    					rs_interrupt(i, NULL, NULL);
    			} else
    #endif /* CONFIG_SERIAL_SHARE_IRQ */
    				rs_interrupt_single(i, NULL, NULL);
    			sti();
    		}
    	}
    	last_strobe = jiffies;
    	timer_table[RS_TIMER].expires = jiffies + RS_STROBE_TIME;
    	timer_active |= 1 << RS_TIMER;

    	if (IRQ_ports[0]) {
    		cli();
    #ifdef CONFIG_SERIAL_SHARE_IRQ
    		rs_interrupt(0, NULL, NULL);
    #else
    		rs_interrupt_single(0, NULL, NULL);
    #endif
    		sti();

    		timer_table[RS_TIMER].expires = jiffies + IRQ_timeout[0] - 2;
    	}
    }

    /*
     * ---------------------------------------------------------------
     * 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 async_struct * info)
    {
    	unsigned long flags;
    	int	retval=0;
    	void (*handler)(int, void *, struct pt_regs *);
    	struct serial_state *state= info->state;
    	unsigned long page;

    	page = get_free_page(GFP_KERNEL);
    	if (!page)
    		return -ENOMEM;

    	save_flags(flags); cli();

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

    	if (!state->port || !state->type) {
    		if (info->tty)
    			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;

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

    	if (uart_config[info->state->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->state->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[state->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 (suser()) {
    			if (info->tty)
    				set_bit(TTY_IO_ERROR, &info->tty->flags);
    		} else
    			retval = -ENODEV;
    		goto errout;
    	}

    	/*
    	 * Allocate the IRQ if necessary
    	 */
    	if (state->irq && (!IRQ_ports[state->irq] ||
    			  !IRQ_ports[state->irq]->next_port)) {
    		if (IRQ_ports[state->irq]) {
    			retval = -EBUSY;
    			goto errout;
    		} else
    			handler = rs_interrupt_single;

    		retval = request_irq(state->irq, handler, IRQ_T(info),
    				     "serial", NULL);
    		if (retval) {
    			if (suser()) {
    				if (info->tty)
    					set_bit(TTY_IO_ERROR,
    						&info->tty->flags);
    				retval = 0;
    			}
    			goto errout;
    		}
    	}

    	/*
    	 * Insert serial port into IRQ chain.
    	 */
    	info->prev_port = 0;
    	info->next_port = IRQ_ports[state->irq];
    	if (info->next_port)
    		info->next_port->prev_port = info;
    	IRQ_ports[state->irq] = info;
    	figure_IRQ_timeout(state->irq);

    	/*
    	 * Clear the interrupt registers.
    	 */
         /* (void) serial_inp(info, UART_LSR); */   /* (see above) */
    	(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->termios->c_cflag & CBAUD)
    		info->MCR = UART_MCR_DTR | UART_MCR_RTS;
    	{
    		if (state->irq != 0)
    			info->MCR |= UART_MCR_OUT2;
    	}
    #if defined(__alpha__) && !defined(CONFIG_PCI)
    	/*
    	 * DEC did something gratutiously wrong....
    	 */
    	info->MCR |= UART_MCR_OUT1 | UART_MCR_OUT2;
    #endif
    	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 serial timers...
    	 */
    	timer_table[RS_TIMER].expires = jiffies + 2*HZ/100;
    	timer_active |= 1 << RS_TIMER;

    	/*
    	 * 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);

    	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 async_struct * info)
    {
    	unsigned long	flags;
    	struct serial_state *state;
    	int		retval;

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

    	state = info->state;

    #ifdef SERIAL_DEBUG_OPEN
    	printk("Shutting down serial port %d (irq %d)....", info->line,
    	       state->irq);
    #endif

    	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);

    	/*
    	 * First unlink the serial port from the IRQ chain...
    	 */
    	if (info->next_port)
    		info->next_port->prev_port = info->prev_port;
    	if (info->prev_port)
    		info->prev_port->next_port = info->next_port;
    	else
    		IRQ_ports[state->irq] = info->next_port;
    	figure_IRQ_timeout(state->irq);

    	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;
    #if defined(__alpha__) && !defined(CONFIG_PCI)
    	/*
    	 * DEC did something gratutiously wrong....
    	 */
    	info->MCR |= UART_MCR_OUT1 | UART_MCR_OUT2;
    #endif

    	/* 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->state->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->state->type == PORT_16750) {
    		/* Arrange to enter sleep mode */
    		serial_outp(info, UART_IER, UART_IERX_SLEEP);
    	}
    	info->flags &= ~ASYNC_INITIALIZED;
    	restore_flags(flags);
    }

    /*
     * This routine is called to set the UART divisor registers to match
     * the specified baud rate for a serial port.
     */
    static void change_speed(struct async_struct *info)
    {
    	unsigned short port;
    	int	quot = 0, baud_base, baud;
    	unsigned cflag, cval, fcr = 0;
    	int	bits;
    	unsigned long	flags;

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

    	/* byte size and parity */
    	switch (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 (cflag & CSTOPB) {
    		cval |= 0x04;
    		bits++;
    	}
    	if (cflag & PARENB) {
    		cval |= UART_LCR_PARITY;
    		bits++;
    	}
    	if (!(cflag & PARODD))
    		cval |= UART_LCR_EPAR;
    #ifdef CMSPAR
    	if (cflag & CMSPAR)
    		cval |= UART_LCR_SPAR;
    #endif

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

    	/* Set up FIFO's */
    	if (uart_config[info->state->type].flags & UART_USE_FIFO) {
    		if ((info->state->baud_base / quot) < 2400)
    			fcr = UART_FCR_ENABLE_FIFO | UART_FCR_TRIGGER_1;
    		else
    			fcr = UART_FCR_ENABLE_FIFO | UART_FCR_TRIGGER_8;
    	}
    	if (info->state->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 (cflag & CRTSCTS) {
    		info->flags |= ASYNC_CTS_FLOW;
    		info->IER |= UART_IER_MSI;
    	} else
    		info->flags &= ~ASYNC_CTS_FLOW;
    	if (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
    	 */
    #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 ((cflag & CREAD) == 0)
    		info->ignore_status_mask |= UART_LSR_DR;
    	save_flags(flags); cli();
    	if (uart_config[info->state->type].flags & UART_STARTECH) {
    		serial_outp(info, UART_LCR, 0xBF);
    		serial_outp(info, UART_EFR,
    			    (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->state->type == PORT_16750)
    		serial_outp(info, UART_FCR, fcr); 	/* set fcr */
    	serial_outp(info, UART_LCR, cval);		/* reset DLAB */
    	if (info->state->type != PORT_16750)
    		serial_outp(info, UART_FCR, fcr); 	/* set fcr */
    	restore_flags(flags);
    }

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

    	if (serial_paranoia_check(info, tty->device, "rs_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 rs_flush_chars(struct tty_struct *tty)
    {
    	struct async_struct *info = (struct async_struct *)tty->driver_data;
    	unsigned long flags;

    	if (serial_paranoia_check(info, tty->device, "rs_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 rs_write(struct tty_struct * tty, int from_user,
    		    const unsigned char *buf, int count)
    {
    	int	c, ret = 0;
    	struct async_struct *info = (struct async_struct *)tty->driver_data;
    	unsigned long flags;

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

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

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

    		if (from_user) {
    			c -= copy_from_user(tmp_buf, buf, c);
    			if (!c) {
    				if (!ret)
    					ret = -EFAULT;
    				break;
    			}
    			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);
    		} else
    			memcpy(info->xmit_buf + info->xmit_head, buf, c);
    		info->xmit_head = (info->xmit_head + c) & (SERIAL_XMIT_SIZE-1);
    		info->xmit_cnt += c;
    		restore_flags(flags);
    		buf += c;
    		count -= c;
    		ret += c;
    	}
    	if (from_user)
    		up(&tmp_buf_sem);
    	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);
    	}
    	restore_flags(flags);
    	return ret;
    }

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

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

    static int rs_chars_in_buffer(struct tty_struct *tty)
    {
    	struct async_struct *info = (struct async_struct *)tty->driver_data;

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

    static void rs_flush_buffer(struct tty_struct *tty)
    {
    	struct async_struct *info = (struct async_struct *)tty->driver_data;

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

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

    	if (serial_paranoia_check(info, tty->device, "rs_send_char"))
    		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);
    	}
    }

    /*
     * ------------------------------------------------------------
     * rs_throttle()
     *
     * This routine is called by the upper-layer tty layer to signal that
     * incoming characters should be throttled.
     * ------------------------------------------------------------
     */
    static void rs_throttle(struct tty_struct * tty)
    {
    	struct async_struct *info = (struct async_struct *)tty->driver_data;
    #ifdef SERIAL_DEBUG_THROTTLE
    	char	buf[64];

    	printk("throttle %s: %d....\n", _tty_name(tty, buf),
    	       tty->ldisc.chars_in_buffer(tty));
    #endif

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

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

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

    	cli();
    	serial_out(info, UART_MCR, info->MCR);
    	sti();
    }

    static void rs_unthrottle(struct tty_struct * tty)
    {
    	struct async_struct *info = (struct async_struct *)tty->driver_data;
    #ifdef SERIAL_DEBUG_THROTTLE
    	char	buf[64];

    	printk("unthrottle %s: %d....\n", _tty_name(tty, buf),
    	       tty->ldisc.chars_in_buffer(tty));
    #endif

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

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

    /*
     * ------------------------------------------------------------
     * rs_ioctl() and friends
     * ------------------------------------------------------------
     */

    static int get_serial_info(struct async_struct * info,
    			   struct serial_struct * retinfo)
    {
    	struct serial_struct tmp;
    	struct serial_state *state = info->state;

    	if (!retinfo)
    		return -EFAULT;
    	memset(&tmp, 0, sizeof(tmp));
    	tmp.type = state->type;
    	tmp.line = state->line;
    	tmp.port = state->port;
    	tmp.irq = state->irq;
    	tmp.flags = state->flags;
    	tmp.xmit_fifo_size = state->xmit_fifo_size;
    	tmp.baud_base = state->baud_base;
    	tmp.close_delay = state->close_delay;
    	tmp.closing_wait = state->closing_wait;
    	tmp.custom_divisor = state->custom_divisor;
    	tmp.hub6 = state->hub6;
    	if (copy_to_user(retinfo,&tmp,sizeof(*retinfo)))
    		return -EFAULT;
    	return 0;
    }

    static int set_serial_info(struct async_struct * info,
    			   struct serial_struct * new_info)
    {
    	struct serial_struct new_serial;
     	struct serial_state old_state, *state;
    	unsigned int		i,change_irq,change_port;
    	int 			retval = 0;

    	if (copy_from_user(&new_serial,new_info,sizeof(new_serial)))
    		return -EFAULT;
    	state = info->state;
    	old_state = *state;

    	change_irq = new_serial.irq != state->irq;
    	change_port = (new_serial.port != state->port) ||
    		(new_serial.hub6 != state->hub6);

    	if (!suser()) {
    		if (change_irq || change_port ||
    		    (new_serial.baud_base != state->baud_base) ||
    		    (new_serial.type != state->type) ||
    		    (new_serial.close_delay != state->close_delay) ||
    		    (new_serial.xmit_fifo_size != state->xmit_fifo_size) ||
    		    ((new_serial.flags & ~ASYNC_USR_MASK) !=
    		     (state->flags & ~ASYNC_USR_MASK)))
    			return -EPERM;
    		state->flags = ((state->flags & ~ASYNC_USR_MASK) |
    			       (new_serial.flags & ASYNC_USR_MASK));
    		state->custom_divisor = new_serial.custom_divisor;
    		goto check_and_exit;
    	}

    	if (new_serial.irq == 2)
    		new_serial.irq = 9;

    	if ((new_serial.irq > 15) || (new_serial.port > 0xffff) ||
    	    (new_serial.type < PORT_UNKNOWN) || (new_serial.type > PORT_MAX)) {
    		return -EINVAL;
    	}

    	/* Make sure address is not already in use */
    	if (new_serial.type) {
    		for (i = 0 ; i < NR_PORTS; i++)
    			if ((state != &rs_table[i]) &&
    			    (rs_table[i].port == new_serial.port) &&
    			    rs_table[i].type)
    				return -EADDRINUSE;
    	}

    	if ((change_port || change_irq) && (state->count > 1))
    		return -EBUSY;

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

    	state->baud_base = new_serial.baud_base;
    	state->flags = ((state->flags & ~ASYNC_FLAGS) |
    			(new_serial.flags & ASYNC_FLAGS));
    	info->flags = ((state->flags & ~ASYNC_INTERNAL_FLAGS) |
    		       (info->flags & ASYNC_INTERNAL_FLAGS));
    	state->custom_divisor = new_serial.custom_divisor;
    	state->type = new_serial.type;
    	state->close_delay = new_serial.close_delay * HZ/100;
    	state->closing_wait = new_serial.closing_wait * HZ/100;
    	info->xmit_fifo_size = state->xmit_fifo_size =
    		new_serial.xmit_fifo_size;

    	release_region(state->port,8);
    	if (change_port || change_irq) {
    		/*
    		 * We need to shutdown the serial port at the old
    		 * port/irq combination.
    		 */
    		shutdown(info);
    		state->irq = new_serial.irq;
    		info->port = state->port = new_serial.port;
    		info->hub6 = state->hub6 = new_serial.hub6;
    	}
    	if (state->type != PORT_UNKNOWN)
    		request_region(state->port,8,"serial(set)");

    check_and_exit:
    	if (!state->port || !state->type)
    		return 0;
    	if (state->type != old_state.type)
    		info->xmit_fifo_size = state->xmit_fifo_size =
    			uart_config[state->type].dfl_xmit_fifo_size;
    	if (state->flags & ASYNC_INITIALIZED) {
    		if (((old_state.flags & ASYNC_SPD_MASK) !=
    		     (state->flags & ASYNC_SPD_MASK)) ||
    		    (old_state.custom_divisor != state->custom_divisor)) {
    			if ((state->flags & ASYNC_SPD_MASK) == ASYNC_SPD_HI)
    				info->tty->alt_speed = 57600;
    			if ((state->flags & ASYNC_SPD_MASK) == ASYNC_SPD_VHI)
    				info->tty->alt_speed = 115200;
    			if ((state->flags & ASYNC_SPD_MASK) == ASYNC_SPD_SHI)
    				info->tty->alt_speed = 230400;
    			if ((state->flags & ASYNC_SPD_MASK) == ASYNC_SPD_WARP)
    				info->tty->alt_speed = 460800;
    			change_speed(info);
    		}
    	} else
    		retval = startup(info);
    	return retval;
    }

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

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

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

    	control = info->MCR;
    	cli();
    	status = serial_in(info, UART_MSR);
    	sti();
    	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 async_struct * info, unsigned int cmd,
    			  unsigned int *value)
    {
    	int error;
    	unsigned int arg;

    	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;
    	}
    	cli();
    	serial_out(info, UART_MCR, info->MCR);
    	sti();
    	return 0;
    }

    /*
     * rs_break() --- routine which turns the break handling on or off
     */
    static void rs_break(struct tty_struct *tty, int break_state)
    {
    	struct async_struct * info = (struct async_struct *)tty->driver_data;
    	unsigned long flags;

    	if (serial_paranoia_check(info, tty->device, "rs_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 rs_ioctl(struct tty_struct *tty, struct file * file,
    		    unsigned int cmd, unsigned long arg)
    {
    	int error;
    	struct async_struct * info = (struct async_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, "rs_ioctl"))
    		return -ENODEV;

    	if ((cmd != TIOCGSERIAL) && (cmd != TIOCSSERIAL) &&
    	    (cmd != TIOCSERCONFIG) && (cmd != TIOCSERGWILD)  &&
    	    (cmd != TIOCSERSWILD) && (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 TIOCGSERIAL:
    			return get_serial_info(info,
    					       (struct serial_struct *) arg);
    		case TIOCSSERIAL:
    			return set_serial_info(info,
    					       (struct serial_struct *) arg);
    		case TIOCSERCONFIG:
    			return do_autoconfig(info);

    		case TIOCSERGWILD:
    			return put_user(rs_wild_int_mask,
    					(unsigned int *) arg);
    		case TIOCSERGETLSR: /* Get line status register */
    			return get_lsr_info(info, (unsigned int *) arg);

    		case TIOCSERSWILD:
    			if (!suser())
    				return -EPERM;
    			error = get_user(rs_wild_int_mask,
    					 (unsigned int *) arg);
    			if (error)
    				return error;
    			if (rs_wild_int_mask < 0)
    				rs_wild_int_mask = check_wild_interrupts(0);
    			return 0;

    		case TIOCSERGSTRUCT:
    			if (copy_to_user((struct async_struct *) arg,
    					 info, sizeof(struct async_struct)))
    				return -EFAULT;
    			return 0;

    		/*
    		 * 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->state->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->state->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->state->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;
    }

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

    	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);

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

    	/* 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;
    		}
    		cli();
    		serial_out(info, UART_MCR, info->MCR);
    		sti();
    	}

    	/* Handle turning off CRTSCTS */
    	if ((old_termios->c_cflag & CRTSCTS) &&
    	    !(tty->termios->c_cflag & CRTSCTS)) {
    		tty->hw_stopped = 0;
    		rs_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
    }

    /*
     * ------------------------------------------------------------
     * rs_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 rs_close(struct tty_struct *tty, struct file * filp)
    {
    	struct async_struct * info = (struct async_struct *)tty->driver_data;
    	struct serial_state *state;
    	unsigned long flags;

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

    	state = info->state;

    	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("rs_close ttys%d, count = %d\n", info->line, state->count);
    #endif
    	if ((tty->count == 1) && (state->count != 1)) {
    		/*
    		 * Uh, oh.  tty->count is 1, which means that the tty
    		 * structure will be freed.  state->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("rs_close: bad serial port count; tty->count is 1, "
    		       "state->count is %d\n", state->count);
    		state->count = 1;
    	}
    	if (--state->count < 0) {
    		printk("rs_close: bad serial port count for ttys%d: %d\n",
    		       info->line, state->count);
    		state->count = 0;
    	}
    	if (state->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->state->normal_termios = *tty->termios;
    	if (info->flags & ASYNC_CALLOUT_ACTIVE)
    		info->state->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!
    		 */
    		rs_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;
    			current->timeout = jiffies + info->close_delay;
    			schedule();
    		}
    		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);
    }

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

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

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

    	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 rs_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;
    		current->counter = 0;	/* make us low-priority */
    		current->timeout = jiffies + char_time;
    		schedule();
    		if (signal_pending(current))
    			break;
    		if (timeout && ((orig_jiffies + timeout) < jiffies))
    			break;
    	}
    	current->state = TASK_RUNNING;
    #ifdef SERIAL_DEBUG_RS_WAIT_UNTIL_SENT
    	printk("lsr = %d (jiff=%lu)...done\n", lsr, jiffies);
    #endif
    }

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

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

    	state = info->state;

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

    /*
     * ------------------------------------------------------------
     * rs_open() and friends
     * ------------------------------------------------------------
     */
    static int block_til_ready(struct tty_struct *tty, struct file * filp,
    			   struct async_struct *info)
    {
    	struct wait_queue wait = { current, NULL };
    	struct serial_state *state = info->state;
    	int		retval;
    	int		do_clocal = 0;

    	/*
    	 * 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 (state->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, state->count is dropped by one, so that
    	 * rs_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",
    	       state->line, state->count);
    #endif
    	cli();
    	if (!tty_hung_up_p(filp))
    		state->count--;
    	sti();
    	info->blocked_open++;
    	while (1) {
    		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));
    		sti();
    		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, state->count);
    #endif
    		schedule();
    	}
    	current->state = TASK_RUNNING;
    	remove_wait_queue(&info->open_wait, &wait);
    	if (!tty_hung_up_p(filp))
    		state->count++;
    	info->blocked_open--;
    #ifdef SERIAL_DEBUG_OPEN
    	printk("block_til_ready after blocking: ttys%d, count = %d\n",
    	       info->line, state->count);
    #endif
    	if (retval)
    		return retval;
    	info->flags |= ASYNC_NORMAL_ACTIVE;
    	return 0;
    }

    static int get_async_struct(int line, struct async_struct **ret_info)
    {
    	struct async_struct *info;
    	struct serial_state *sstate;

    	sstate = rs_table + line;
    	sstate->count++;
    	if (sstate->info) {
    		*ret_info = sstate->info;
    		return 0;
    	}
    	info = kmalloc(sizeof(struct async_struct), GFP_KERNEL);
    	if (!info) {
    		sstate->count--;
    		return -ENOMEM;
    	}
    	memset(info, 0, sizeof(struct async_struct));
    	info->magic = SERIAL_MAGIC;
    	info->port = sstate->port;
    	info->flags = sstate->flags;
    	info->xmit_fifo_size = sstate->xmit_fifo_size;
    	info->line = line;
    	info->tqueue.routine = do_softint;
    	info->tqueue.data = info;
    	info->state = sstate;
    	if (sstate->info) {
    		kfree_s(info, sizeof(struct async_struct));
    		*ret_info = sstate->info;
    		return 0;
    	}
    	*ret_info = sstate->info = info;
    	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 rs_open(struct tty_struct *tty, struct file * filp)
    {
    	struct async_struct	*info;
    	int 			retval, line;
    	unsigned long		page;

    	line = MINOR(tty->device) - tty->driver.minor_start;
    	if ((line < 0) || (line >= NR_PORTS))
    		return -ENODEV;
    	retval = get_async_struct(line, &info);
    	if (retval)
    		return retval;
    	if (serial_paranoia_check(info, tty->device, "rs_open"))
    		return -ENODEV;

    #ifdef SERIAL_DEBUG_OPEN
    	printk("rs_open %s%d, count = %d\n", tty->driver.name, info->line,
    	       info->state->count);
    #endif
    	tty->driver_data = info;
    	info->tty = tty;

    	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("rs_open returning after block_til_ready with %d\n",
    		       retval);
    #endif
    		return retval;
    	}

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

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

    /*
     * /proc fs routines....
     */

    static int inline line_info(char *buf, struct serial_state *state)
    {
    	struct async_struct *info = state->info, scr_info;
    	char	stat_buf[30], control, status;
    	int	ret;

    	ret = sprintf(buf, "%d: uart:%s port:%X irq:%d",
    		      state->line, uart_config[state->type].name,
    		      state->port, state->irq);

    	if (!state->port || (state->type == PORT_UNKNOWN)) {
    		ret += sprintf(buf+ret, "\n");
    		return ret;
    	}

    	/*
    	 * Figure out the current RS-232 lines
    	 */
    	if (!info) {
    		info = &scr_info;	/* This is just for serial_{in,out} */

    		info->magic = SERIAL_MAGIC;
    		info->port = state->port;
    		info->flags = state->flags;
    		info->quot = 0;
    		info->tty = 0;
    	}
    	cli();
    	status = serial_in(info, UART_MSR);
    	control = info ? info->MCR : serial_in(info, UART_MCR);
    	sti();

    	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:%d",
    			       state->baud_base / info->quot);
    	}

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

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

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

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

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

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

    int rs_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, &rs_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 + (begin-off);
    	return ((count < begin+len-off) ? count : begin+len-off);
    }

    /*
     * ---------------------------------------------------------------------
     * rs_init() and friends
     *
     * rs_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 show_serial_version(void)
    {
     	printk(KERN_INFO "ISDN %s version %s enabled", serial_name, serial_version);
    }

    /*
     * This routine is called by rs_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 or not, since this will
     * determine whether or not we can use its FIFO features or not.
     */
    static void autoconfig(struct serial_state * state)
    {
    	unsigned char status1, status2, scratch, scratch2;
    	struct async_struct *info, scr_info;
    	unsigned long flags;

    	state->type = PORT_UNKNOWN;

    	if (!state->port)
    		return;

    	info = &scr_info;	/* This is just for serial_{in,out} */

    	info->magic = SERIAL_MAGIC;
    	info->port = state->port;
    	info->flags = state->flags;

    	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);
    	outb(0xff, 0x080);
    	scratch2 = serial_inp(info, UART_IER);
    	serial_outp(info, UART_IER, scratch);
    	if (scratch2) {
    		restore_flags(flags);
    		return;		/* We failed; there's nothing here */
    	}

    	/*
    	 * Check to see if a UART is really there.  Certain broken
    	 * internal modems based on the Rockwell chipset fail this
    	 * test, because they apparently don't implement the loopback
    	 * test mode.  So this test is skipped on the COM 1 through
    	 * COM 4 ports.  This *should* be safe, since no board
    	 * manufacturer would be stupid enough to design a board
    	 * that conflicts with COM 1-4 --- we hope!
    	 */
    	if (!(state->flags & ASYNC_SKIP_TEST)) {
    		scratch = serial_inp(info, UART_MCR);
    		serial_outp(info, UART_MCR, UART_MCR_LOOP | scratch);
    		scratch2 = serial_inp(info, UART_MSR);
    		serial_outp(info, UART_MCR, UART_MCR_LOOP | 0x0A);
    		status1 = serial_inp(info, UART_MSR) & 0xF0;
    		serial_outp(info, UART_MCR, scratch);
    		serial_outp(info, UART_MSR, scratch2);
    		if (status1 != 0x90) {
    			restore_flags(flags);
    			return;
    		}
    	}

    	/*
    	 * If the AUTO_IRQ flag is set, try to do the automatic IRQ
    	 * detection.
    	 */
    	if (state->flags & ASYNC_AUTO_IRQ)
    		state->irq = do_auto_irq(info);

    	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:
    			state->type = PORT_16450;
    			break;
    		case 1:
    			state->type = PORT_UNKNOWN;
    			break;
    		case 2:
    			state->type = PORT_16550;
    			break;
    		case 3:
    			state->type = PORT_16550A;
    			break;
    	}
    	if (state->type == PORT_16550A) {
    		/* Check for Startech UART's */
    		serial_outp(info, UART_LCR, scratch2 | UART_LCR_DLAB);
    		if (serial_in(info, UART_EFR) == 0) {
    			state->type = PORT_16650;
    		} else {
    			serial_outp(info, UART_LCR, 0xBF);
    			if (serial_in(info, UART_EFR) == 0)
    				state->type = PORT_16650V2;
    		}
    	}
    	if (state->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);
    			scratch = serial_in(info, UART_IIR) >> 5;
    			if (scratch == 6)
    				state->type = PORT_16750;
    		}
    		serial_outp(info, UART_FCR, UART_FCR_ENABLE_FIFO);
    	}
    	serial_outp(info, UART_LCR, scratch2);
    	if (state->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))
    			state->type = PORT_8250;
    	}
    	state->xmit_fifo_size =	uart_config[state->type].dfl_xmit_fifo_size;

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

    	request_region(info->port,8,"serial(auto)");

    	/*
    	 * Reset the UART.
    	 */
    #if defined(__alpha__) && !defined(CONFIG_PCI)
    	/*
    	 * I wonder what DEC did to the OUT1 and OUT2 lines?
    	 * clearing them results in endless interrupts.
    	 */
    	serial_outp(info, UART_MCR, 0x0c);
    #else
    	serial_outp(info, UART_MCR, 0x00);
    #endif
    	serial_outp(info, UART_FCR, (UART_FCR_CLEAR_RCVR |
    				     UART_FCR_CLEAR_XMIT));
    	(void)serial_in(info, UART_RX);

    	restore_flags(flags);
    }

    /*
     * The serial driver boot-time initialization code!
     */
    __initfunc(int rs_init(void))
    {
    	int i;
    	struct serial_state * state;

    	init_bh(SERIAL_BH, do_serial_bh);
    	timer_table[RS_TIMER].fn = rs_timer;
    	timer_table[RS_TIMER].expires = 0;
    #ifdef CONFIG_AUTO_IRQ
    	rs_wild_int_mask = check_wild_interrupts(1);
    #endif

    	for (i = 0; i < 16; i++) {
    		IRQ_ports[i] = 0;
    		IRQ_timeout[i] = 0;
    #ifdef CONFIG_SERIAL_MULTIPORT
    		memset(&rs_multiport[i], 0,
    		       sizeof(struct rs_multiport_struct));
    #endif
    	}
    #ifdef CONFIG_SERIAL_CONSOLE
    	/*
    	 *	The interrupt of the serial console port
    	 *	can't be shared.
    	 */
    	if (sercons.flags & CON_FIRST) {
    		for(i = 0; i < NR_PORTS; i++)
    			if (i != sercons.index &&
    			    rs_table[i].irq == rs_table[sercons.index].irq)
    				rs_table[i].irq = 0;
    	}
    #endif
    	show_serial_version();

    	/* Initialize the tty_driver structure */

    	memset(&serial_driver, 0, sizeof(struct tty_driver));
    	serial_driver.magic = TTY_DRIVER_MAGIC;
    	serial_driver.driver_name = "serial";
    	serial_driver.name = "ttyS";
    	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 = rs_open;
    	serial_driver.close = rs_close;
    	serial_driver.write = rs_write;
    	serial_driver.put_char = rs_put_char;
    	serial_driver.flush_chars = rs_flush_chars;
    	serial_driver.write_room = rs_write_room;
    	serial_driver.chars_in_buffer = rs_chars_in_buffer;
    	serial_driver.flush_buffer = rs_flush_buffer;
    	serial_driver.ioctl = rs_ioctl;
    	serial_driver.throttle = rs_throttle;
    	serial_driver.unthrottle = rs_unthrottle;
    	serial_driver.send_xchar = rs_send_xchar;
    	serial_driver.set_termios = rs_set_termios;
    	serial_driver.stop = rs_stop;
    	serial_driver.start = rs_start;
    	serial_driver.hangup = rs_hangup;
    	serial_driver.break_ctl = rs_break;
    	serial_driver.wait_until_sent = rs_wait_until_sent;
    	serial_driver.read_proc = rs_read_proc;

    	/*
    	 * The callout device is just like normal device except for
    	 * major number and the subtype code.
    	 */
    	callout_driver = serial_driver;
    	callout_driver.name = "cua";
    	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 serial driver\n");
    	if (tty_register_driver(&callout_driver))
    		panic("Couldn't register callout driver\n");

    	for (i = 0, state = rs_table; i < NR_PORTS; i++,state++) {
    		state->magic = SSTATE_MAGIC;
    		state->line = i;
    		state->type = PORT_UNKNOWN;
    		state->custom_divisor = 0;
    		state->close_delay = 5*HZ/10;
    		state->closing_wait = 30*HZ;
    		state->callout_termios = callout_driver.init_termios;
    		state->normal_termios = serial_driver.init_termios;
    		state->icount.cts = state->icount.dsr =
    			state->icount.rng = state->icount.dcd = 0;
    		state->icount.rx = state->icount.tx = 0;
    		state->icount.frame = state->icount.parity = 0;
    		state->icount.overrun = state->icount.brk = 0;
    		if (state->irq == 2)
    			state->irq = 9;
    		if (state->type == PORT_UNKNOWN) {
    			if (!(state->flags & ASYNC_BOOT_AUTOCONF))
    				continue;
    			if (check_region(state->port,8))
    				continue;
    			autoconfig(state);
    			if (state->type == PORT_UNKNOWN)
    				continue;
    		}
    		printk(KERN_INFO "ttyS%02d%s at 0x%04x (irq = %d) is a %s\n",
    		       state->line,
    		       (state->flags & ASYNC_FOURPORT) ? " FourPort" : "",
    		       state->port, state->irq,
    		       uart_config[state->type].name);
    	}
    	return 0;
    }

    #ifdef MODULE
    int init_module(void)
    {
    	return rs_init();
    }

    void cleanup_module(void)
    {
    	unsigned long flags;
    	int e1, e2;
    	int i;

    	/* printk("Unloading %s: version %s\n", serial_name, serial_version); */
    	save_flags(flags);
    	cli();
    	timer_active &= ~(1 << RS_TIMER);
    	timer_table[RS_TIMER].fn = NULL;
    	timer_table[RS_TIMER].expires = 0;
            remove_bh(SERIAL_BH);
    	if ((e1 = tty_unregister_driver(&serial_driver)))
    		printk("SERIAL: failed to unregister serial driver (%d)\n",
    		       e1);
    	if ((e2 = tty_unregister_driver(&callout_driver)))
    		printk("SERIAL: failed to unregister callout driver (%d)\n",
    		       e2);
    	restore_flags(flags);

    	for (i = 0; i < NR_PORTS; i++) {
    		if (rs_table[i].type != PORT_UNKNOWN)
    			release_region(rs_table[i].port, 8);
    	}
    	if (tmp_buf) {
    		free_page((unsigned long) tmp_buf);
    		tmp_buf = NULL;
    	}
    }
    #endif /* MODULE */