/*
 *  esp.c - driver for Hayes ESP serial cards
 *
 *  --- Notices from serial.c, upon which this driver is based ---
 *
 *  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.
 *
 * --- End of notices from serial.c ---
 *
 * Support for the ESP serial card by Andrew J. Robinson
 *     <arobinso@nyx.net> (Card detection routine taken from a patch
 *     by Dennis J. Boylan).  Patches to allow use with 2.1.x contributed
 *     by Chris Faylor.
 *
 * Most recent changes: (Andrew J. Robinson)
 *   Support for PIO mode.  This allows the driver to work properly with
 *     multiport cards.
 *
 * Arnaldo Carvalho de Melo <acme@conectiva.com.br> -
 * several cleanups, use module_init/module_exit, etc
 *
 * This module exports the following rs232 io functions:
 *
 *      int espserial_init(void);
 */

#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/major.h>
#include <linux/string.h>
#include <linux/fcntl.h>
#include <linux/ptrace.h>
#include <linux/ioport.h>
#include <linux/mm.h>
#include <linux/init.h>

#include <asm/system.h>
#include <asm/io.h>
#include <asm/segment.h>
#include <asm/bitops.h>

#include <asm/dma.h>
#include <linux/slab.h>
#include <asm/uaccess.h>

#include <linux/hayesesp.h>

#define NR_PORTS 64     /* maximum number of ports */
#define NR_PRIMARY 8    /* maximum number of primary ports */

/* The following variables can be set by giving module options */
static int irq[NR_PRIMARY];     /* IRQ for each base port */
static unsigned int divisor[NR_PRIMARY]; /* custom divisor for each port */
static unsigned int dma = ESP_DMA_CHANNEL; /* DMA channel */
static unsigned int rx_trigger = ESP_RX_TRIGGER;
static unsigned int tx_trigger = ESP_TX_TRIGGER;
static unsigned int flow_off = ESP_FLOW_OFF;
static unsigned int flow_on = ESP_FLOW_ON;
static unsigned int rx_timeout = ESP_RX_TMOUT;
static unsigned int pio_threshold = ESP_PIO_THRESHOLD;

MODULE_LICENSE("GPL");

MODULE_PARM(irq, "1-8i");
MODULE_PARM(divisor, "1-8i");
MODULE_PARM(dma, "i");
MODULE_PARM(rx_trigger, "i");
MODULE_PARM(tx_trigger, "i");
MODULE_PARM(flow_off, "i");
MODULE_PARM(flow_on, "i");
MODULE_PARM(rx_timeout, "i");
MODULE_PARM(pio_threshold, "i");

/* END */

static char *dma_buffer;
static int dma_bytes;
static struct esp_pio_buffer *free_pio_buf;

#define DMA_BUFFER_SZ 1024

#define WAKEUP_CHARS 1024

static char serial_name[] __initdata = "ESP serial driver";
static char serial_version[] __initdata = "2.2";

static DECLARE_TASK_QUEUE(tq_esp);

static struct tty_driver esp_driver, esp_callout_driver;
static int serial_refcount;

/* serial subtype definitions */
#define SERIAL_TYPE_NORMAL      1
#define SERIAL_TYPE_CALLOUT     2

/*
 * Serial driver configuration section.  Here are the various options:
 *
 * SERIAL_PARANOIA_CHECK
 *              Check the magic number for the esp_structure where
 *              ever possible.
 */

#undef SERIAL_PARANOIA_CHECK
#define SERIAL_DO_RESTART

#undef SERIAL_DEBUG_INTR
#undef SERIAL_DEBUG_OPEN
#undef SERIAL_DEBUG_FLOW

#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

static struct esp_struct *ports;

static void change_speed(struct esp_struct *info);
static void rs_wait_until_sent(struct tty_struct *, int);
        
/*
 * The ESP card has a clock rate of 14.7456 MHz (that is, 2**ESPC_SCALE
 * times the normal 1.8432 Mhz clock of most serial boards).
 */
#define BASE_BAUD ((1843200 / 16) * (1 << ESPC_SCALE))

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

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

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

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

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

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

/*
 * ------------------------------------------------------------
 * 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 esp_struct *info = (struct esp_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_ESI_CMD1, ESI_SET_SRV_MASK);
                serial_out(info, UART_ESI_CMD2, info->IER);
        }

        restore_flags(flags);
}

static void rs_start(struct tty_struct *tty)
{
        struct esp_struct *info = (struct esp_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_ESI_CMD1, ESI_SET_SRV_MASK);
                serial_out(info, UART_ESI_CMD2, 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 esp_struct *info,
                                  int event)
{
        info->event |= 1 << event;
        queue_task(&info->tqueue, &tq_esp);
        mark_bh(ESP_BH);
}
static _INLINE_ struct esp_pio_buffer *get_pio_buffer(void)
{
        struct esp_pio_buffer *buf;

        if (free_pio_buf) {
                buf = free_pio_buf;
                free_pio_buf = buf->next;
        } else {
                buf = kmalloc(sizeof(struct esp_pio_buffer), GFP_ATOMIC);
        }

        return buf;
}

static _INLINE_ void release_pio_buffer(struct esp_pio_buffer *buf)
{
        buf->next = free_pio_buf;
        free_pio_buf = buf;
}

static _INLINE_ void receive_chars_pio(struct esp_struct *info, int num_bytes)
{
        struct tty_struct *tty = info->tty;
        int i;
        struct esp_pio_buffer *pio_buf;
        struct esp_pio_buffer *err_buf;
        unsigned char status_mask;

        pio_buf = get_pio_buffer();

        if (!pio_buf)
                return;

        err_buf = get_pio_buffer();

        if (!err_buf) {
                release_pio_buffer(pio_buf);
                return;
        }

        sti();
        
        status_mask = (info->read_status_mask >> 2) & 0x07;
                
        for (i = 0; i < num_bytes - 1; i += 2) {
                *((unsigned short *)(pio_buf->data + i)) =
                        inw(info->port + UART_ESI_RX);
                err_buf->data[i] = serial_in(info, UART_ESI_RWS);
                err_buf->data[i + 1] = (err_buf->data[i] >> 3) & status_mask;
                err_buf->data[i] &= status_mask;
        }

        if (num_bytes & 0x0001) {
                pio_buf->data[num_bytes - 1] = serial_in(info, UART_ESI_RX);
                err_buf->data[num_bytes - 1] =
                        (serial_in(info, UART_ESI_RWS) >> 3) & status_mask;
        }

        cli();

        /* make sure everything is still ok since interrupts were enabled */
        tty = info->tty;

        if (!tty) {
                release_pio_buffer(pio_buf);
                release_pio_buffer(err_buf);
                info->stat_flags &= ~ESP_STAT_RX_TIMEOUT;
                return;
        }

        status_mask = (info->ignore_status_mask >> 2) & 0x07;

        for (i = 0; i < num_bytes; i++) {
                if (!(err_buf->data[i] & status_mask)) {
                        *(tty->flip.char_buf_ptr++) = pio_buf->data[i];

                        if (err_buf->data[i] & 0x04) {
                                *(tty->flip.flag_buf_ptr++) = TTY_BREAK;

                                if (info->flags & ASYNC_SAK)
                                        do_SAK(tty);
                        }
                        else if (err_buf->data[i] & 0x02)
                                *(tty->flip.flag_buf_ptr++) = TTY_FRAME;
                        else if (err_buf->data[i] & 0x01)
                                *(tty->flip.flag_buf_ptr++) = TTY_PARITY;
                        else
                                *(tty->flip.flag_buf_ptr++) = 0;
                
                        tty->flip.count++;
                }
        }

        queue_task(&tty->flip.tqueue, &tq_timer);

        info->stat_flags &= ~ESP_STAT_RX_TIMEOUT;
        release_pio_buffer(pio_buf);
        release_pio_buffer(err_buf);
}

static _INLINE_ void receive_chars_dma(struct esp_struct *info, int num_bytes)
{
        unsigned long flags;
        info->stat_flags &= ~ESP_STAT_RX_TIMEOUT;
        dma_bytes = num_bytes;
        info->stat_flags |= ESP_STAT_DMA_RX;
        
        flags=claim_dma_lock();
        disable_dma(dma);
        clear_dma_ff(dma);
        set_dma_mode(dma, DMA_MODE_READ);
        set_dma_addr(dma, virt_to_bus(dma_buffer));
        set_dma_count(dma, dma_bytes);
        enable_dma(dma);
        release_dma_lock(flags);
        
        serial_out(info, UART_ESI_CMD1, ESI_START_DMA_RX);
}

static _INLINE_ void receive_chars_dma_done(struct esp_struct *info,
                                            int status)
{
        struct tty_struct *tty = info->tty;
        int num_bytes;
        unsigned long flags;
        
        
        flags=claim_dma_lock();
        disable_dma(dma);
        clear_dma_ff(dma);

        info->stat_flags &= ~ESP_STAT_DMA_RX;
        num_bytes = dma_bytes - get_dma_residue(dma);
        release_dma_lock(flags);
        
        info->icount.rx += num_bytes;

        memcpy(tty->flip.char_buf_ptr, dma_buffer, num_bytes);
        tty->flip.char_buf_ptr += num_bytes;
        tty->flip.count += num_bytes;
        memset(tty->flip.flag_buf_ptr, 0, num_bytes);
        tty->flip.flag_buf_ptr += num_bytes;

        if (num_bytes > 0) {
                tty->flip.flag_buf_ptr--;

                status &= (0x1c & info->read_status_mask);

                if (status & info->ignore_status_mask) {
                        tty->flip.count--;
                        tty->flip.char_buf_ptr--;
                        tty->flip.flag_buf_ptr--;
                } else if (status & 0x10) {
                        *tty->flip.flag_buf_ptr = TTY_BREAK;
                        (info->icount.brk)++;
                        if (info->flags & ASYNC_SAK)
                                do_SAK(tty);
                } else if (status & 0x08) {
                        *tty->flip.flag_buf_ptr = TTY_FRAME;
                        (info->icount.frame)++;
                }
                else if (status & 0x04) {
                        *tty->flip.flag_buf_ptr = TTY_PARITY;
                        (info->icount.parity)++;
                }

                tty->flip.flag_buf_ptr++;
                
                queue_task(&tty->flip.tqueue, &tq_timer);
        }

        if (dma_bytes != num_bytes) {
                num_bytes = dma_bytes - num_bytes;
                dma_bytes = 0;
                receive_chars_dma(info, num_bytes);
        } else
                dma_bytes = 0;
}

static _INLINE_ void transmit_chars_pio(struct esp_struct *info,
                                        int space_avail)
{
        int i;
        struct esp_pio_buffer *pio_buf;

        pio_buf = get_pio_buffer();

        if (!pio_buf)
                return;

        while (space_avail && info->xmit_cnt) {
                if (info->xmit_tail + space_avail <= ESP_XMIT_SIZE) {
                        memcpy(pio_buf->data,
                               &(info->xmit_buf[info->xmit_tail]),
                               space_avail);
                } else {
                        i = ESP_XMIT_SIZE - info->xmit_tail;
                        memcpy(pio_buf->data,
                               &(info->xmit_buf[info->xmit_tail]), i);
                        memcpy(&(pio_buf->data[i]), info->xmit_buf,
                               space_avail - i);
                }

                info->xmit_cnt -= space_avail;
                info->xmit_tail = (info->xmit_tail + space_avail) &
                        (ESP_XMIT_SIZE - 1);

                sti();

                for (i = 0; i < space_avail - 1; i += 2) {
                        outw(*((unsigned short *)(pio_buf->data + i)),
                             info->port + UART_ESI_TX);
                }

                if (space_avail & 0x0001)
                        serial_out(info, UART_ESI_TX,
                                   pio_buf->data[space_avail - 1]);

                cli();

                if (info->xmit_cnt) {
                        serial_out(info, UART_ESI_CMD1, ESI_NO_COMMAND);
                        serial_out(info, UART_ESI_CMD1, ESI_GET_TX_AVAIL);
                        space_avail = serial_in(info, UART_ESI_STAT1) << 8;
                        space_avail |= serial_in(info, UART_ESI_STAT2);

                        if (space_avail > info->xmit_cnt)
                                space_avail = info->xmit_cnt;
                }
        }

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

#ifdef SERIAL_DEBUG_INTR
                printk("THRE...");
#endif

                if (info->xmit_cnt <= 0) {
                        info->IER &= ~UART_IER_THRI;
                        serial_out(info, UART_ESI_CMD1,
                                   ESI_SET_SRV_MASK);
                        serial_out(info, UART_ESI_CMD2, info->IER);
                }
        }

        release_pio_buffer(pio_buf);
}

static _INLINE_ void transmit_chars_dma(struct esp_struct *info, int num_bytes)
{
        unsigned long flags;
        
        dma_bytes = num_bytes;

        if (info->xmit_tail + dma_bytes <= ESP_XMIT_SIZE) {
                memcpy(dma_buffer, &(info->xmit_buf[info->xmit_tail]),
                       dma_bytes);
        } else {
                int i = ESP_XMIT_SIZE - info->xmit_tail;
                memcpy(dma_buffer, &(info->xmit_buf[info->xmit_tail]),
                        i);
                memcpy(&(dma_buffer[i]), info->xmit_buf, dma_bytes - i);
        }

        info->xmit_cnt -= dma_bytes;
        info->xmit_tail = (info->xmit_tail + dma_bytes) & (ESP_XMIT_SIZE - 1);

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

#ifdef SERIAL_DEBUG_INTR
                printk("THRE...");
#endif

                if (info->xmit_cnt <= 0) {
                        info->IER &= ~UART_IER_THRI;
                        serial_out(info, UART_ESI_CMD1, ESI_SET_SRV_MASK);
                        serial_out(info, UART_ESI_CMD2, info->IER);
                }
        }

        info->stat_flags |= ESP_STAT_DMA_TX;
        
        flags=claim_dma_lock();
        disable_dma(dma);
        clear_dma_ff(dma);
        set_dma_mode(dma, DMA_MODE_WRITE);
        set_dma_addr(dma, virt_to_bus(dma_buffer));
        set_dma_count(dma, dma_bytes);
        enable_dma(dma);
        release_dma_lock(flags);
        
        serial_out(info, UART_ESI_CMD1, ESI_START_DMA_TX);
}

static _INLINE_ void transmit_chars_dma_done(struct esp_struct *info)
{
        int num_bytes;
        unsigned long flags;
        

        flags=claim_dma_lock();
        disable_dma(dma);
        clear_dma_ff(dma);

        num_bytes = dma_bytes - get_dma_residue(dma);
        info->icount.tx += dma_bytes;
        release_dma_lock(flags);

        if (dma_bytes != num_bytes) {
                dma_bytes -= num_bytes;
                memmove(dma_buffer, dma_buffer + num_bytes, dma_bytes);
                
                flags=claim_dma_lock();
                disable_dma(dma);
                clear_dma_ff(dma);
                set_dma_mode(dma, DMA_MODE_WRITE);
                set_dma_addr(dma, virt_to_bus(dma_buffer));
                set_dma_count(dma, dma_bytes);
                enable_dma(dma);
                release_dma_lock(flags);
                
                serial_out(info, UART_ESI_CMD1, ESI_START_DMA_TX);
        } else {
                dma_bytes = 0;
                info->stat_flags &= ~ESP_STAT_DMA_TX;
        }
}

static _INLINE_ void check_modem_status(struct esp_struct *info)
{
        int     status;
        
        serial_out(info, UART_ESI_CMD1, ESI_GET_UART_STAT);
        status = serial_in(info, UART_ESI_STAT2);

        if (status & UART_MSR_ANY_DELTA) {
                /* update input line counters */
                if (status & UART_MSR_TERI)
                        info->icount.rng++;
                if (status & UART_MSR_DDSR)
                        info->icount.dsr++;
                if (status & UART_MSR_DDCD)
                        info->icount.dcd++;
                if (status & UART_MSR_DCTS)
                        info->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("scheduling hangup...");
#endif
                        MOD_INC_USE_COUNT;
                        if (schedule_task(&info->tqueue_hangup) == 0)
                                MOD_DEC_USE_COUNT;
                }
        }
}

/*
 * This is the serial driver's interrupt routine
 */
static void rs_interrupt_single(int irq, void *dev_id, struct pt_regs * regs)
{
        struct esp_struct * info;
        unsigned err_status;
        unsigned int scratch;

#ifdef SERIAL_DEBUG_INTR
        printk("rs_interrupt_single(%d)...", irq);
#endif
        info = (struct esp_struct *)dev_id;
        err_status = 0;
        scratch = serial_in(info, UART_ESI_SID);

        cli();
        
        if (!info->tty) {
                sti();
                return;
        }

        if (scratch & 0x04) { /* error */
                serial_out(info, UART_ESI_CMD1, ESI_GET_ERR_STAT);
                err_status = serial_in(info, UART_ESI_STAT1);
                serial_in(info, UART_ESI_STAT2);

                if (err_status & 0x01)
                        info->stat_flags |= ESP_STAT_RX_TIMEOUT;

                if (err_status & 0x20) /* UART status */
                        check_modem_status(info);

                if (err_status & 0x80) /* Start break */
                        wake_up_interruptible(&info->break_wait);
        }
                
        if ((scratch & 0x88) || /* DMA completed or timed out */
            (err_status & 0x1c) /* receive error */) {
                if (info->stat_flags & ESP_STAT_DMA_RX)
                        receive_chars_dma_done(info, err_status);
                else if (info->stat_flags & ESP_STAT_DMA_TX)
                        transmit_chars_dma_done(info);
        }

        if (!(info->stat_flags & (ESP_STAT_DMA_RX | ESP_STAT_DMA_TX)) &&
            ((scratch & 0x01) || (info->stat_flags & ESP_STAT_RX_TIMEOUT)) &&
            (info->IER & UART_IER_RDI)) {
                int num_bytes;

                serial_out(info, UART_ESI_CMD1, ESI_NO_COMMAND);
                serial_out(info, UART_ESI_CMD1, ESI_GET_RX_AVAIL);
                num_bytes = serial_in(info, UART_ESI_STAT1) << 8;
                num_bytes |= serial_in(info, UART_ESI_STAT2);

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

                if (num_bytes) {
                        if (dma_bytes ||
                            (info->stat_flags & ESP_STAT_USE_PIO) ||
                            (num_bytes <= info->config.pio_threshold))
                                receive_chars_pio(info, num_bytes);
                        else
                                receive_chars_dma(info, num_bytes);
                }
        }
        
        if (!(info->stat_flags & (ESP_STAT_DMA_RX | ESP_STAT_DMA_TX)) &&
            (scratch & 0x02) && (info->IER & UART_IER_THRI)) {
                if ((info->xmit_cnt <= 0) || info->tty->stopped) {
                        info->IER &= ~UART_IER_THRI;
                        serial_out(info, UART_ESI_CMD1, ESI_SET_SRV_MASK);
                        serial_out(info, UART_ESI_CMD2, info->IER);
                } else {
                        int num_bytes;

                        serial_out(info, UART_ESI_CMD1, ESI_NO_COMMAND);
                        serial_out(info, UART_ESI_CMD1, ESI_GET_TX_AVAIL);
                        num_bytes = serial_in(info, UART_ESI_STAT1) << 8;
                        num_bytes |= serial_in(info, UART_ESI_STAT2);

                        if (num_bytes > info->xmit_cnt)
                                num_bytes = info->xmit_cnt;

                        if (num_bytes) {
                                if (dma_bytes ||
                                    (info->stat_flags & ESP_STAT_USE_PIO) ||
                                    (num_bytes <= info->config.pio_threshold))
                                        transmit_chars_pio(info, num_bytes);
                                else
                                        transmit_chars_dma(info, num_bytes);
                        }
                }
        }

        info->last_active = jiffies;

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

/*
 * -------------------------------------------------------------------
 * 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_esp);
}

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

        if (test_and_clear_bit(ESP_EVENT_WRITE_WAKEUP, &info->event)) {
                tty_wakeup(tty);
        }
}

/*
 * This routine is called from the scheduler tqueue when the interrupt
 * routine has signalled that a hangup has occurred.  The path of
 * hangup processing is:
 *
 *      serial interrupt routine -> (scheduler tqueue) ->
 *      do_serial_hangup() -> tty->hangup() -> esp_hangup()
 * 
 */
static void do_serial_hangup(void *private_)
{
        struct esp_struct       *info = (struct esp_struct *) private_;
        struct tty_struct       *tty;
        
        tty = info->tty;
        if (tty)
                tty_hangup(tty);
        MOD_DEC_USE_COUNT;
}

/*
 * ---------------------------------------------------------------
 * 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 _INLINE_ void esp_basic_init(struct esp_struct * info)
{
        /* put ESPC in enhanced mode */
        serial_out(info, UART_ESI_CMD1, ESI_SET_MODE);
        
        if (info->stat_flags & ESP_STAT_NEVER_DMA)
                serial_out(info, UART_ESI_CMD2, 0x01);
        else
                serial_out(info, UART_ESI_CMD2, 0x31);

        /* disable interrupts for now */
        serial_out(info, UART_ESI_CMD1, ESI_SET_SRV_MASK);
        serial_out(info, UART_ESI_CMD2, 0x00);

        /* set interrupt and DMA channel */
        serial_out(info, UART_ESI_CMD1, ESI_SET_IRQ);

        if (info->stat_flags & ESP_STAT_NEVER_DMA)
                serial_out(info, UART_ESI_CMD2, 0x01);
        else
                serial_out(info, UART_ESI_CMD2, (dma << 4) | 0x01);

        serial_out(info, UART_ESI_CMD1, ESI_SET_ENH_IRQ);

        if (info->line % 8)     /* secondary port */
                serial_out(info, UART_ESI_CMD2, 0x0d);  /* shared */
        else if (info->irq == 9)
                serial_out(info, UART_ESI_CMD2, 0x02);
        else
                serial_out(info, UART_ESI_CMD2, info->irq);

        /* set error status mask (check this) */
        serial_out(info, UART_ESI_CMD1, ESI_SET_ERR_MASK);

        if (info->stat_flags & ESP_STAT_NEVER_DMA)
                serial_out(info, UART_ESI_CMD2, 0xa1);
        else
                serial_out(info, UART_ESI_CMD2, 0xbd);

        serial_out(info, UART_ESI_CMD2, 0x00);

        /* set DMA timeout */
        serial_out(info, UART_ESI_CMD1, ESI_SET_DMA_TMOUT);
        serial_out(info, UART_ESI_CMD2, 0xff);

        /* set FIFO trigger levels */
        serial_out(info, UART_ESI_CMD1, ESI_SET_TRIGGER);
        serial_out(info, UART_ESI_CMD2, info->config.rx_trigger >> 8);
        serial_out(info, UART_ESI_CMD2, info->config.rx_trigger);
        serial_out(info, UART_ESI_CMD2, info->config.tx_trigger >> 8);
        serial_out(info, UART_ESI_CMD2, info->config.tx_trigger);

        /* Set clock scaling and wait states */
        serial_out(info, UART_ESI_CMD1, ESI_SET_PRESCALAR);
        serial_out(info, UART_ESI_CMD2, 0x04 | ESPC_SCALE);

        /* set reinterrupt pacing */
        serial_out(info, UART_ESI_CMD1, ESI_SET_REINTR);
        serial_out(info, UART_ESI_CMD2, 0xff);
}

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

        save_flags(flags); cli();

        if (info->flags & ASYNC_INITIALIZED)
                goto out;

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

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

        /* Flush the RX buffer.  Using the ESI flush command may cause */
        /* wild interrupts, so read all the data instead. */

        serial_out(info, UART_ESI_CMD1, ESI_NO_COMMAND);
        serial_out(info, UART_ESI_CMD1, ESI_GET_RX_AVAIL);
        num_chars = serial_in(info, UART_ESI_STAT1) << 8;
        num_chars |= serial_in(info, UART_ESI_STAT2);

        while (num_chars > 1) {
                inw(info->port + UART_ESI_RX);
                num_chars -= 2;
        }

        if (num_chars)
                serial_in(info, UART_ESI_RX);

        /* set receive character timeout */
        serial_out(info, UART_ESI_CMD1, ESI_SET_RX_TIMEOUT);
        serial_out(info, UART_ESI_CMD2, info->config.rx_timeout);

        /* clear all flags except the "never DMA" flag */
        info->stat_flags &= ESP_STAT_NEVER_DMA;

        if (info->stat_flags & ESP_STAT_NEVER_DMA)
                info->stat_flags |= ESP_STAT_USE_PIO;

        /*
         * Allocate the IRQ
         */

        retval = request_irq(info->irq, rs_interrupt_single, SA_SHIRQ,
                             "esp serial", info);

        if (retval) {
                if (capable(CAP_SYS_ADMIN)) {
                        if (info->tty)
                                set_bit(TTY_IO_ERROR,
                                        &info->tty->flags);
                        retval = 0;
                }
                goto out;
        }

        if (!(info->stat_flags & ESP_STAT_USE_PIO) && !dma_buffer) {
                dma_buffer = (char *)__get_dma_pages(
                        GFP_KERNEL, get_order(DMA_BUFFER_SZ));

                /* use PIO mode if DMA buf/chan cannot be allocated */
                if (!dma_buffer)
                        info->stat_flags |= ESP_STAT_USE_PIO;
                else if (request_dma(dma, "esp serial")) {
                        free_pages((unsigned long)dma_buffer,
                                   get_order(DMA_BUFFER_SZ));
                        dma_buffer = 0;
                        info->stat_flags |= ESP_STAT_USE_PIO;
                }
                        
        }

        info->MCR = UART_MCR_DTR | UART_MCR_RTS | UART_MCR_OUT2;
        serial_out(info, UART_ESI_CMD1, ESI_WRITE_UART);
        serial_out(info, UART_ESI_CMD2, UART_MCR);
        serial_out(info, UART_ESI_CMD2, info->MCR);
        
        /*
         * Finally, enable interrupts
         */
        /* info->IER = UART_IER_MSI | UART_IER_RLSI | UART_IER_RDI; */
        info->IER = UART_IER_RLSI | UART_IER_RDI | UART_IER_DMA_TMOUT |
                        UART_IER_DMA_TC;
        serial_out(info, UART_ESI_CMD1, ESI_SET_SRV_MASK);
        serial_out(info, UART_ESI_CMD2, info->IER);
        
        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;
        }
        
        /*
         * set the speed of the serial port
         */
        change_speed(info);

        info->flags |= ASYNC_INITIALIZED;
        retval = 0;
out:    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 esp_struct * info)
{
        unsigned long   flags, f;

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

#ifdef SERIAL_DEBUG_OPEN
        printk("Shutting down serial port %d (irq %d)....", info->line,
               info->irq);
#endif
        
        save_flags(flags); cli(); /* Disable interrupts */

        /*
         * 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);
        wake_up_interruptible(&info->break_wait);

        /* stop a DMA transfer on the port being closed */
           
        if (info->stat_flags & (ESP_STAT_DMA_RX | ESP_STAT_DMA_TX)) {
                f=claim_dma_lock();
                disable_dma(dma);
                clear_dma_ff(dma);
                release_dma_lock(f);
                
                dma_bytes = 0;
        }
        
        /*
         * Free the IRQ
         */
        free_irq(info->irq, info);

        if (dma_buffer) {
                struct esp_struct *current_port = ports;

                while (current_port) {
                        if ((current_port != info) &&
                            (current_port->flags & ASYNC_INITIALIZED))
                                break;

                        current_port = current_port->next_port;
                }

                if (!current_port) {
                        free_dma(dma);
                        free_pages((unsigned long)dma_buffer,
                                   get_order(DMA_BUFFER_SZ));
                        dma_buffer = 0;
                }               
        }

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

        info->IER = 0;
        serial_out(info, UART_ESI_CMD1, ESI_SET_SRV_MASK);
        serial_out(info, UART_ESI_CMD2, 0x00);

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

        info->MCR &= ~UART_MCR_OUT2;
        serial_out(info, UART_ESI_CMD1, ESI_WRITE_UART);
        serial_out(info, UART_ESI_CMD2, UART_MCR);
        serial_out(info, UART_ESI_CMD2, info->MCR);

        if (info->tty)
                set_bit(TTY_IO_ERROR, &info->tty->flags);
        
        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 esp_struct *info)
{
        unsigned short port;
        int     quot = 0;
        unsigned cflag,cval;
        int     baud, bits;
        unsigned char flow1 = 0, flow2 = 0;
        unsigned long flags;

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

        baud = tty_get_baud_rate(info->tty);
        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*BASE_BAUD / 269);
                else if (baud)
                        quot = BASE_BAUD / baud;
        }
        /* If the quotient is ever zero, default to 9600 bps */
        if (!quot)
                quot = BASE_BAUD / 9600;
        
        info->timeout = ((1024 * HZ * bits * quot) / BASE_BAUD) + (HZ / 50);

        /* CTS flow control flag and modem status interrupts */
        /* info->IER &= ~UART_IER_MSI; */
        if (cflag & CRTSCTS) {
                info->flags |= ASYNC_CTS_FLOW;
                /* info->IER |= UART_IER_MSI; */
                flow1 = 0x04;
                flow2 = 0x10;
        } 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; */
        }

        /*
         * 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;
        
        info->ignore_status_mask = 0;
#if 0
        /* This should be safe, but for some broken bits of hardware... */
        if (I_IGNPAR(info->tty)) {
                info->ignore_status_mask |= UART_LSR_PE | UART_LSR_FE;
                info->read_status_mask |= UART_LSR_PE | UART_LSR_FE;
        }
#endif
        if (I_IGNBRK(info->tty)) {
                info->ignore_status_mask |= UART_LSR_BI;
                info->read_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 | \
                                UART_LSR_PE | UART_LSR_FE;
                        info->read_status_mask |= UART_LSR_OE | \
                                UART_LSR_PE | UART_LSR_FE;
                }
        }

        if (I_IXOFF(info->tty))
                flow1 |= 0x81;

        save_flags(flags); cli();
        /* set baud */
        serial_out(info, UART_ESI_CMD1, ESI_SET_BAUD);
        serial_out(info, UART_ESI_CMD2, quot >> 8);
        serial_out(info, UART_ESI_CMD2, quot & 0xff);

        /* set data bits, parity, etc. */
        serial_out(info, UART_ESI_CMD1, ESI_WRITE_UART);
        serial_out(info, UART_ESI_CMD2, UART_LCR);
        serial_out(info, UART_ESI_CMD2, cval);

        /* Enable flow control */
        serial_out(info, UART_ESI_CMD1, ESI_SET_FLOW_CNTL);
        serial_out(info, UART_ESI_CMD2, flow1);
        serial_out(info, UART_ESI_CMD2, flow2);

        /* set flow control characters (XON/XOFF only) */
        if (I_IXOFF(info->tty)) {
                serial_out(info, UART_ESI_CMD1, ESI_SET_FLOW_CHARS);
                serial_out(info, UART_ESI_CMD2, START_CHAR(info->tty));
                serial_out(info, UART_ESI_CMD2, STOP_CHAR(info->tty));
                serial_out(info, UART_ESI_CMD2, 0x10);
                serial_out(info, UART_ESI_CMD2, 0x21);
                switch (cflag & CSIZE) {
                        case CS5:
                                serial_out(info, UART_ESI_CMD2, 0x1f);
                                break;
                        case CS6:
                                serial_out(info, UART_ESI_CMD2, 0x3f);
                                break;
                        case CS7:
                        case CS8:
                                serial_out(info, UART_ESI_CMD2, 0x7f);
                                break;
                        default:
                                serial_out(info, UART_ESI_CMD2, 0xff);
                                break;
                }
        }

        /* Set high/low water */
        serial_out(info, UART_ESI_CMD1, ESI_SET_FLOW_LVL);
        serial_out(info, UART_ESI_CMD2, info->config.flow_off >> 8);
        serial_out(info, UART_ESI_CMD2, info->config.flow_off);
        serial_out(info, UART_ESI_CMD2, info->config.flow_on >> 8);
        serial_out(info, UART_ESI_CMD2, info->config.flow_on);

        restore_flags(flags);
}

static void rs_put_char(struct tty_struct *tty, unsigned char ch)
{
        struct esp_struct *info = (struct esp_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 >= ESP_XMIT_SIZE - 1) {
                restore_flags(flags);
                return;
        }

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

static void rs_flush_chars(struct tty_struct *tty)
{
        struct esp_struct *info = (struct esp_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 || !info->xmit_buf)
                return;

        save_flags(flags); cli();
        if (!(info->IER & UART_IER_THRI)) {
                info->IER |= UART_IER_THRI;
                serial_out(info, UART_ESI_CMD1, ESI_SET_SRV_MASK);
                serial_out(info, UART_ESI_CMD2, info->IER);
        }
        restore_flags(flags);
}

static int rs_write(struct tty_struct * tty, int from_user,
                    const unsigned char *buf, int count)
{
        int     c, t, ret = 0;
        struct esp_struct *info = (struct esp_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);

        while (1) {
                /* Thanks to R. Wolff for suggesting how to do this with */
                /* interrupts enabled */

                c = count;
                t = ESP_XMIT_SIZE - info->xmit_cnt - 1;
                
                if (t < c)
                        c = t;

                t = ESP_XMIT_SIZE - info->xmit_head;
                
                if (t < c)
                        c = t;

                if (c <= 0)
                        break;

                if (from_user) {
                        c -= copy_from_user(tmp_buf, buf, c);

                        if (!c) {
                                if (!ret)
                                        ret = -EFAULT;
                                break;
                        }

                        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) & (ESP_XMIT_SIZE-1);
                info->xmit_cnt += c;
                buf += c;
                count -= c;
                ret += c;
        }

        if (from_user)
                up(&tmp_buf_sem);
        
        save_flags(flags); cli();

        if (info->xmit_cnt && !tty->stopped && !(info->IER & UART_IER_THRI)) {
                info->IER |= UART_IER_THRI;
                serial_out(info, UART_ESI_CMD1, ESI_SET_SRV_MASK);
                serial_out(info, UART_ESI_CMD2, info->IER);
        }

        restore_flags(flags);
        return ret;
}

static int rs_write_room(struct tty_struct *tty)
{
        struct esp_struct *info = (struct esp_struct *)tty->driver_data;
        int     ret;
                                
        if (serial_paranoia_check(info, tty->device, "rs_write_room"))
                return 0;
        ret = ESP_XMIT_SIZE - info->xmit_cnt - 1;
        if (ret < 0)
                ret = 0;
        return ret;
}

static int rs_chars_in_buffer(struct tty_struct *tty)
{
        struct esp_struct *info = (struct esp_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 esp_struct *info = (struct esp_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();
        tty_wakeup(tty);
}

/*
 * ------------------------------------------------------------
 * 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 esp_struct *info = (struct esp_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;
        
        cli();
        info->IER &= ~UART_IER_RDI;
        serial_out(info, UART_ESI_CMD1, ESI_SET_SRV_MASK);
        serial_out(info, UART_ESI_CMD2, info->IER);
        serial_out(info, UART_ESI_CMD1, ESI_SET_RX_TIMEOUT);
        serial_out(info, UART_ESI_CMD2, 0x00);
        sti();
}

static void rs_unthrottle(struct tty_struct * tty)
{
        struct esp_struct *info = (struct esp_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;
        
        cli();
        info->IER |= UART_IER_RDI;
        serial_out(info, UART_ESI_CMD1, ESI_SET_SRV_MASK);
        serial_out(info, UART_ESI_CMD2, info->IER);
        serial_out(info, UART_ESI_CMD1, ESI_SET_RX_TIMEOUT);
        serial_out(info, UART_ESI_CMD2, info->config.rx_timeout);
        sti();
}

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

static int get_serial_info(struct esp_struct * info,
                           struct serial_struct * retinfo)
{
        struct serial_struct tmp;
  
        if (!retinfo)
                return -EFAULT;
        memset(&tmp, 0, sizeof(tmp));
        tmp.type = PORT_16550A;
        tmp.line = info->line;
        tmp.port = info->port;
        tmp.irq = info->irq;
        tmp.flags = info->flags;
        tmp.xmit_fifo_size = 1024;
        tmp.baud_base = BASE_BAUD;
        tmp.close_delay = info->close_delay;
        tmp.closing_wait = info->closing_wait;
        tmp.custom_divisor = info->custom_divisor;
        tmp.hub6 = 0;
        if (copy_to_user(retinfo,&tmp,sizeof(*retinfo)))
                return -EFAULT;
        return 0;
}

static int get_esp_config(struct esp_struct * info,
                          struct hayes_esp_config * retinfo)
{
        struct hayes_esp_config tmp;
  
        if (!retinfo)
                return -EFAULT;

        memset(&tmp, 0, sizeof(tmp));
        tmp.rx_timeout = info->config.rx_timeout;
        tmp.rx_trigger = info->config.rx_trigger;
        tmp.tx_trigger = info->config.tx_trigger;
        tmp.flow_off = info->config.flow_off;
        tmp.flow_on = info->config.flow_on;
        tmp.pio_threshold = info->config.pio_threshold;
        tmp.dma_channel = (info->stat_flags & ESP_STAT_NEVER_DMA ? 0 : dma);

        return copy_to_user(retinfo, &tmp, sizeof(*retinfo)) ? -EFAULT : 0;
}

static int set_serial_info(struct esp_struct * info,
                           struct serial_struct * new_info)
{
        struct serial_struct new_serial;
        struct esp_struct old_info;
        unsigned int change_irq;
        int retval = 0;
        struct esp_struct *current_async;

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

        if ((new_serial.type != PORT_16550A) ||
            (new_serial.hub6) ||
            (info->port != new_serial.port) ||
            (new_serial.baud_base != BASE_BAUD) ||
            (new_serial.irq > 15) ||
            (new_serial.irq < 2) ||
            (new_serial.irq == 6) ||
            (new_serial.irq == 8) ||
            (new_serial.irq == 13))
                return -EINVAL;

        change_irq = new_serial.irq != info->irq;

        if (change_irq && (info->line % 8))
                return -EINVAL;

        if (!capable(CAP_SYS_ADMIN)) {
                if (change_irq || 
                    (new_serial.close_delay != info->close_delay) ||
                    ((new_serial.flags & ~ASYNC_USR_MASK) !=
                     (info->flags & ~ASYNC_USR_MASK)))
                        return -EPERM;
                info->flags = ((info->flags & ~ASYNC_USR_MASK) |
                               (new_serial.flags & ASYNC_USR_MASK));
                info->custom_divisor = new_serial.custom_divisor;
        } else {
                if (new_serial.irq == 2)
                        new_serial.irq = 9;

                if (change_irq) {
                        current_async = ports;

                        while (current_async) {
                                if ((current_async->line >= info->line) &&
                                    (current_async->line < (info->line + 8))) {
                                        if (current_async == info) {
                                                if (current_async->count > 1)
                                                        return -EBUSY;
                                        } else if (current_async->count)
                                                return -EBUSY;
                                }

                                current_async = current_async->next_port;
                        }
                }

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

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

                if (change_irq) {
                        /*
                         * We need to shutdown the serial port at the old
                         * port/irq combination.
                         */
                        shutdown(info);

                        current_async = ports;

                        while (current_async) {
                                if ((current_async->line >= info->line) &&
                                    (current_async->line < (info->line + 8)))
                                        current_async->irq = new_serial.irq;

                                current_async = current_async->next_port;
                        }

                        serial_out(info, UART_ESI_CMD1, ESI_SET_ENH_IRQ);
                        if (info->irq == 9)
                                serial_out(info, UART_ESI_CMD2, 0x02);
                        else
                                serial_out(info, UART_ESI_CMD2, info->irq);
                }
        }

        if (info->flags & ASYNC_INITIALIZED) {
                if (((old_info.flags & ASYNC_SPD_MASK) !=
                     (info->flags & ASYNC_SPD_MASK)) ||
                    (old_info.custom_divisor != info->custom_divisor)) {
                        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;
                        change_speed(info);
                }
        } else
                retval = startup(info);

        return retval;
}

static int set_esp_config(struct esp_struct * info,
                          struct hayes_esp_config * new_info)
{
        struct hayes_esp_config new_config;
        unsigned int change_dma;
        int retval = 0;
        struct esp_struct *current_async;

        /* Perhaps a non-sysadmin user should be able to do some of these */
        /* operations.  I haven't decided yet. */

        if (!capable(CAP_SYS_ADMIN))
                return -EPERM;

        if (copy_from_user(&new_config, new_info, sizeof(new_config)))
                return -EFAULT;

        if ((new_config.flow_on >= new_config.flow_off) ||
            (new_config.rx_trigger < 1) ||
            (new_config.tx_trigger < 1) ||
            (new_config.flow_off < 1) ||
            (new_config.flow_on < 1) ||
            (new_config.rx_trigger > 1023) ||
            (new_config.tx_trigger > 1023) ||
            (new_config.flow_off > 1023) ||
            (new_config.flow_on > 1023) ||
            (new_config.pio_threshold < 0) ||
            (new_config.pio_threshold > 1024))
                return -EINVAL;

        if ((new_config.dma_channel != 1) && (new_config.dma_channel != 3))
                new_config.dma_channel = 0;

        if (info->stat_flags & ESP_STAT_NEVER_DMA)
                change_dma = new_config.dma_channel;
        else
                change_dma = (new_config.dma_channel != dma);

        if (change_dma) {
                if (new_config.dma_channel) {
                        /* PIO mode to DMA mode transition OR */
                        /* change current DMA channel */
                        
                        current_async = ports;

                        while (current_async) {
                                if (current_async == info) {
                                        if (current_async->count > 1)
                                                return -EBUSY;
                                } else if (current_async->count)
                                        return -EBUSY;
                                        
                                current_async =
                                        current_async->next_port;
                        }

                        shutdown(info);
                        dma = new_config.dma_channel;
                        info->stat_flags &= ~ESP_STAT_NEVER_DMA;
                        
                        /* all ports must use the same DMA channel */

                        current_async = ports;

                        while (current_async) {
                                esp_basic_init(current_async);
                                current_async = current_async->next_port;
                        }
                } else {
                        /* DMA mode to PIO mode only */
                        
                        if (info->count > 1)
                                return -EBUSY;

                        shutdown(info);
                        info->stat_flags |= ESP_STAT_NEVER_DMA;
                        esp_basic_init(info);
                }
        }

        info->config.pio_threshold = new_config.pio_threshold;

        if ((new_config.flow_off != info->config.flow_off) ||
            (new_config.flow_on != info->config.flow_on)) {
                unsigned long flags;

                info->config.flow_off = new_config.flow_off;
                info->config.flow_on = new_config.flow_on;
                save_flags(flags); cli();
                serial_out(info, UART_ESI_CMD1, ESI_SET_FLOW_LVL);
                serial_out(info, UART_ESI_CMD2, new_config.flow_off >> 8);
                serial_out(info, UART_ESI_CMD2, new_config.flow_off);
                serial_out(info, UART_ESI_CMD2, new_config.flow_on >> 8);
                serial_out(info, UART_ESI_CMD2, new_config.flow_on);
                restore_flags(flags);
        }

        if ((new_config.rx_trigger != info->config.rx_trigger) ||
            (new_config.tx_trigger != info->config.tx_trigger)) {
                unsigned long flags;

                info->config.rx_trigger = new_config.rx_trigger;
                info->config.tx_trigger = new_config.tx_trigger;
                save_flags(flags); cli();
                serial_out(info, UART_ESI_CMD1, ESI_SET_TRIGGER);
                serial_out(info, UART_ESI_CMD2,
                           new_config.rx_trigger >> 8);
                serial_out(info, UART_ESI_CMD2, new_config.rx_trigger);
                serial_out(info, UART_ESI_CMD2,
                           new_config.tx_trigger >> 8);
                serial_out(info, UART_ESI_CMD2, new_config.tx_trigger);
                restore_flags(flags);
        }

        if (new_config.rx_timeout != info->config.rx_timeout) {
                unsigned long flags;

                info->config.rx_timeout = new_config.rx_timeout;
                save_flags(flags); cli();

                if (info->IER & UART_IER_RDI) {
                        serial_out(info, UART_ESI_CMD1,
                                   ESI_SET_RX_TIMEOUT);
                        serial_out(info, UART_ESI_CMD2,
                                   new_config.rx_timeout);
                }

                restore_flags(flags);
        }

        if (!(info->flags & ASYNC_INITIALIZED))
                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 esp_struct * info, unsigned int *value)
{
        unsigned char status;
        unsigned int result;

        cli();
        serial_out(info, UART_ESI_CMD1, ESI_GET_UART_STAT);
        status = serial_in(info, UART_ESI_STAT1);
        sti();
        result = ((status & UART_LSR_TEMT) ? TIOCSER_TEMT : 0);
        return put_user(result,value);
}


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

        control = info->MCR;
        cli();
        serial_out(info, UART_ESI_CMD1, ESI_GET_UART_STAT);
        status = serial_in(info, UART_ESI_STAT2);
        sti();
        result =  ((control & UART_MCR_RTS) ? TIOCM_RTS : 0)
                | ((control & UART_MCR_DTR) ? TIOCM_DTR : 0)
                | ((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 esp_struct * info, unsigned int cmd,
                          unsigned int *value)
{
        unsigned int arg;

        if (get_user(arg, value))
                return -EFAULT;

        switch (cmd) {
        case TIOCMBIS: 
                if (arg & TIOCM_RTS)
                        info->MCR |= UART_MCR_RTS;
                if (arg & TIOCM_DTR)
                        info->MCR |= UART_MCR_DTR;
                break;
        case TIOCMBIC:
                if (arg & TIOCM_RTS)
                        info->MCR &= ~UART_MCR_RTS;
                if (arg & TIOCM_DTR)
                        info->MCR &= ~UART_MCR_DTR;
                break;
        case TIOCMSET:
                info->MCR = ((info->MCR & ~(UART_MCR_RTS | UART_MCR_DTR))
                             | ((arg & TIOCM_RTS) ? UART_MCR_RTS : 0)
                             | ((arg & TIOCM_DTR) ? UART_MCR_DTR : 0));
                break;
        default:
                return -EINVAL;
        }
        cli();
        serial_out(info, UART_ESI_CMD1, ESI_WRITE_UART);
        serial_out(info, UART_ESI_CMD2, UART_MCR);
        serial_out(info, UART_ESI_CMD2, info->MCR);
        sti();
        return 0;
}

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

        save_flags(flags); cli();
        if (break_state == -1) {
                serial_out(info, UART_ESI_CMD1, ESI_ISSUE_BREAK);
                serial_out(info, UART_ESI_CMD2, 0x01);

                interruptible_sleep_on(&info->break_wait);
        } else {
                serial_out(info, UART_ESI_CMD1, ESI_ISSUE_BREAK);
                serial_out(info, UART_ESI_CMD2, 0x00);
        }
        restore_flags(flags);
}

static int rs_ioctl(struct tty_struct *tty, struct file * file,
                    unsigned int cmd, unsigned long arg)
{
        struct esp_struct * info = (struct esp_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) &&
            (cmd != TIOCGHAYESESP) && (cmd != TIOCSHAYESESP)) {
                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:
                        /* do not reconfigure after initial configuration */
                        return 0;

                case TIOCSERGWILD:
                        return put_user(0L, (unsigned long *) arg);

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

                case TIOCSERSWILD:
                        if (!capable(CAP_SYS_ADMIN))
                                return -EPERM;
                        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();
                        cprev = info->icount;   /* note the counters on entry */
                        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;
                        if (put_user(cnow.cts, &p_cuser->cts) ||
                            put_user(cnow.dsr, &p_cuser->dsr) ||
                            put_user(cnow.rng, &p_cuser->rng) ||
                            put_user(cnow.dcd, &p_cuser->dcd))
                                return -EFAULT;

                        return 0;
        case TIOCGHAYESESP:
                return (get_esp_config(info, (struct hayes_esp_config *)arg));
        case TIOCSHAYESESP:
                return (set_esp_config(info, (struct hayes_esp_config *)arg));

                default:
                        return -ENOIOCTLCMD;
                }
        return 0;
}

static void rs_set_termios(struct tty_struct *tty, struct termios *old_termios)
{
        struct esp_struct *info = (struct esp_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_ESI_CMD1, ESI_WRITE_UART);
                serial_out(info, UART_ESI_CMD2, UART_MCR);
                serial_out(info, UART_ESI_CMD2, 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 | UART_MCR_RTS);
                cli();
                serial_out(info, UART_ESI_CMD1, ESI_WRITE_UART);
                serial_out(info, UART_ESI_CMD2, UART_MCR);
                serial_out(info, UART_ESI_CMD2, info->MCR);
                sti();
        }

        /* Handle turning of CRTSCTS */
        if ((old_termios->c_cflag & CRTSCTS) &&
            !(tty->termios->c_cflag & CRTSCTS)) {
                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 esp_struct * info = (struct esp_struct *)tty->driver_data;
        unsigned long flags;

        if (!info || serial_paranoia_check(info, tty->device, "rs_close"))
                return;
        
        save_flags(flags); cli();
        
        if (tty_hung_up_p(filp)) {
                DBG_CNT("before DEC-hung");
                goto out;
        }
        
#ifdef SERIAL_DEBUG_OPEN
        printk("rs_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("rs_close: bad serial port count; tty->count is 1, "
                       "info->count is %d\n", info->count);
                info->count = 1;
        }
        if (--info->count < 0) {
                printk("rs_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");
                goto out;
        }
        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->IER &= ~UART_IER_RDI;
        info->read_status_mask &= ~UART_LSR_DR;
        if (info->flags & ASYNC_INITIALIZED) {
                serial_out(info, UART_ESI_CMD1, ESI_SET_SRV_MASK);
                serial_out(info, UART_ESI_CMD2, info->IER);

                /* disable receive timeout */
                serial_out(info, UART_ESI_CMD1, ESI_SET_RX_TIMEOUT);
                serial_out(info, UART_ESI_CMD2, 0x00);

                /*
                 * 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);
        tty_ldisc_flush(tty);
        tty->closing = 0;
        info->event = 0;
        info->tty = 0;

        if (info->blocked_open) {
                if (info->close_delay) {
                        set_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);
out:    MOD_DEC_USE_COUNT;
        restore_flags(flags);
}

static void rs_wait_until_sent(struct tty_struct *tty, int timeout)
{
        struct esp_struct *info = (struct esp_struct *)tty->driver_data;
        unsigned long orig_jiffies, char_time;
        unsigned long flags;

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

        orig_jiffies = jiffies;
        char_time = ((info->timeout - HZ / 50) / 1024) / 5;

        if (!char_time)
                char_time = 1;

        save_flags(flags); cli();
        serial_out(info, UART_ESI_CMD1, ESI_NO_COMMAND);
        serial_out(info, UART_ESI_CMD1, ESI_GET_TX_AVAIL);

        while ((serial_in(info, UART_ESI_STAT1) != 0x03) ||
                (serial_in(info, UART_ESI_STAT2) != 0xff)) {
                set_current_state(TASK_INTERRUPTIBLE);
                schedule_timeout(char_time);

                if (signal_pending(current))
                        break;

                if (timeout && time_after(jiffies, orig_jiffies + timeout))
                        break;

                serial_out(info, UART_ESI_CMD1, ESI_NO_COMMAND);
                serial_out(info, UART_ESI_CMD1, ESI_GET_TX_AVAIL);
        }
        
        restore_flags(flags);
        set_current_state(TASK_RUNNING);
}

/*
 * esp_hangup() --- called by tty_hangup() when a hangup is signaled.
 */
static void esp_hangup(struct tty_struct *tty)
{
        struct esp_struct * info = (struct esp_struct *)tty->driver_data;
        
        if (serial_paranoia_check(info, tty->device, "esp_hangup"))
                return;
        
        rs_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);
}

/*
 * ------------------------------------------------------------
 * esp_open() and friends
 * ------------------------------------------------------------
 */
static int block_til_ready(struct tty_struct *tty, struct file * filp,
                           struct esp_struct *info)
{
        DECLARE_WAITQUEUE(wait, current);
        int             retval;
        int             do_clocal = 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
                if (info->flags & ASYNC_HUP_NOTIFY)
                        return -EAGAIN;
                else
                        return -ERESTARTSYS;
#else
                return -EAGAIN;
#endif
        }

        /*
         * If this is a callout device, then just make sure the normal
         * device isn't being used.
         */
        if (tty->driver.subtype == SERIAL_TYPE_CALLOUT) {
                if (info->flags & 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
         * 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",
               info->line, info->count);
#endif
        save_flags(flags);
        cli();
        if (!tty_hung_up_p(filp)) 
                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)) {
                        unsigned int scratch;

                        serial_out(info, UART_ESI_CMD1, ESI_READ_UART);
                        serial_out(info, UART_ESI_CMD2, UART_MCR);
                        scratch = serial_in(info, UART_ESI_STAT1);
                        serial_out(info, UART_ESI_CMD1, ESI_WRITE_UART);
                        serial_out(info, UART_ESI_CMD2, UART_MCR);
                        serial_out(info, UART_ESI_CMD2,
                                scratch | 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;
                }

                serial_out(info, UART_ESI_CMD1, ESI_GET_UART_STAT);
                if (serial_in(info, UART_ESI_STAT2) & UART_MSR_DCD)
                        do_clocal = 1;

                if (!(info->flags & ASYNC_CALLOUT_ACTIVE) &&
                    !(info->flags & ASYNC_CLOSING) &&
                    (do_clocal))
                        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();
        }
        set_current_state(TASK_RUNNING);
        remove_wait_queue(&info->open_wait, &wait);
        if (!tty_hung_up_p(filp))
                info->count++;
        info->blocked_open--;
#ifdef SERIAL_DEBUG_OPEN
        printk("block_til_ready after blocking: ttys%d, count = %d\n",
               info->line, info->count);
#endif
        if (retval)
                return retval;
        info->flags |= 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 esp_open(struct tty_struct *tty, struct file * filp)
{
        struct esp_struct       *info;
        int                     retval, line;

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

        /* find the port in the chain */

        info = ports;

        while (info && (info->line != line))
                info = info->next_port;

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

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

        if (!tmp_buf) {
                tmp_buf = (unsigned char *) get_free_page(GFP_KERNEL);
                if (!tmp_buf)
                        return -ENOMEM;
        }
        
        /*
         * Start up serial port
         */
        retval = startup(info);
        if (retval)
                return retval;

        retval = block_til_ready(tty, filp, info);
        if (retval) {
#ifdef SERIAL_DEBUG_OPEN
                printk("esp_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);
        }

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

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

/*
 * ---------------------------------------------------------------------
 * espserial_init() and friends
 *
 * espserial_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 "%s version %s (DMA %u)\n",
                serial_name, serial_version, dma);
}

/*
 * This routine is called by espserial_init() to initialize a specific serial
 * port.
 */
static _INLINE_ int autoconfig(struct esp_struct * info, int *region_start)
{
        int port_detected = 0;
        unsigned long flags;

        save_flags(flags); cli();
        
        /*
         * Check for ESP card
         */

        if (!check_region(info->port, 8) && 
            serial_in(info, UART_ESI_BASE) == 0xf3) {
                serial_out(info, UART_ESI_CMD1, 0x00);
                serial_out(info, UART_ESI_CMD1, 0x01);

                if ((serial_in(info, UART_ESI_STAT2) & 0x70) == 0x20) {
                        port_detected = 1;

                        if (!(info->irq)) {
                                serial_out(info, UART_ESI_CMD1, 0x02);

                                if (serial_in(info, UART_ESI_STAT1) & 0x01)
                                        info->irq = 3;
                                else
                                        info->irq = 4;
                        }

                        if (ports && (ports->port == (info->port - 8))) {
                                release_region(*region_start,
                                               info->port - *region_start);
                        } else
                                *region_start = info->port;

                        request_region(*region_start,
                                       info->port - *region_start + 8,
                                       "esp serial");

                        /* put card in enhanced mode */
                        /* this prevents access through */
                        /* the "old" IO ports */
                        esp_basic_init(info);

                        /* clear out MCR */
                        serial_out(info, UART_ESI_CMD1, ESI_WRITE_UART);
                        serial_out(info, UART_ESI_CMD2, UART_MCR);
                        serial_out(info, UART_ESI_CMD2, 0x00);
                }
        }

        restore_flags(flags);
        return (port_detected);
}

/*
 * The serial driver boot-time initialization code!
 */
int __init espserial_init(void)
{
        int i, offset;
        int region_start;
        struct esp_struct * info;
        struct esp_struct *last_primary = 0;
        int esp[] = {0x100,0x140,0x180,0x200,0x240,0x280,0x300,0x380};
        
        init_bh(ESP_BH, do_serial_bh);

        for (i = 0; i < NR_PRIMARY; i++) {
                if (irq[i] != 0) {
                        if ((irq[i] < 2) || (irq[i] > 15) || (irq[i] == 6) ||
                            (irq[i] == 8) || (irq[i] == 13))
                                irq[i] = 0;
                        else if (irq[i] == 2)
                                irq[i] = 9;
                }
        }

        if ((dma != 1) && (dma != 3))
                dma = 0;

        if ((rx_trigger < 1) || (rx_trigger > 1023))
                rx_trigger = 768;

        if ((tx_trigger < 1) || (tx_trigger > 1023))
                tx_trigger = 768;

        if ((flow_off < 1) || (flow_off > 1023))
                flow_off = 1016;
        
        if ((flow_on < 1) || (flow_on > 1023))
                flow_on = 944;

        if ((rx_timeout < 0) || (rx_timeout > 255))
                rx_timeout = 128;
        
        if (flow_on >= flow_off)
                flow_on = flow_off - 1;

        show_serial_version();

        /* Initialize the tty_driver structure */
        
        memset(&esp_driver, 0, sizeof(struct tty_driver));
        esp_driver.magic = TTY_DRIVER_MAGIC;
        esp_driver.name = "ttyP";
        esp_driver.major = ESP_IN_MAJOR;
        esp_driver.minor_start = 0;
        esp_driver.num = NR_PORTS;
        esp_driver.type = TTY_DRIVER_TYPE_SERIAL;
        esp_driver.subtype = SERIAL_TYPE_NORMAL;
        esp_driver.init_termios = tty_std_termios;
        esp_driver.init_termios.c_cflag =
                B9600 | CS8 | CREAD | HUPCL | CLOCAL;
        esp_driver.flags = TTY_DRIVER_REAL_RAW;
        esp_driver.refcount = &serial_refcount;
        esp_driver.table = serial_table;
        esp_driver.termios = serial_termios;
        esp_driver.termios_locked = serial_termios_locked;

        esp_driver.open = esp_open;
        esp_driver.close = rs_close;
        esp_driver.write = rs_write;
        esp_driver.put_char = rs_put_char;
        esp_driver.flush_chars = rs_flush_chars;
        esp_driver.write_room = rs_write_room;
        esp_driver.chars_in_buffer = rs_chars_in_buffer;
        esp_driver.flush_buffer = rs_flush_buffer;
        esp_driver.ioctl = rs_ioctl;
        esp_driver.throttle = rs_throttle;
        esp_driver.unthrottle = rs_unthrottle;
        esp_driver.set_termios = rs_set_termios;
        esp_driver.stop = rs_stop;
        esp_driver.start = rs_start;
        esp_driver.hangup = esp_hangup;
        esp_driver.break_ctl = esp_break;
        esp_driver.wait_until_sent = rs_wait_until_sent;

        /*
         * The callout device is just like normal device except for
         * major number and the subtype code.
         */
        esp_callout_driver = esp_driver;
        esp_callout_driver.name = "cup";
        esp_callout_driver.major = ESP_OUT_MAJOR;
        esp_callout_driver.subtype = SERIAL_TYPE_CALLOUT;

        if (tty_register_driver(&esp_driver))
        {
                printk(KERN_ERR "Couldn't register esp serial driver");
                return 1;
        }

        if (tty_register_driver(&esp_callout_driver))
        {
                printk(KERN_ERR "Couldn't register esp callout driver");
                tty_unregister_driver(&esp_driver);
                return 1;
        }
        
        info = kmalloc(sizeof(struct esp_struct), GFP_KERNEL);

        if (!info)
        {
                printk(KERN_ERR "Couldn't allocate memory for esp serial device information\n");
                tty_unregister_driver(&esp_driver);
                tty_unregister_driver(&esp_callout_driver);
                return 1;
        }

        memset((void *)info, 0, sizeof(struct esp_struct));
        /* rx_trigger, tx_trigger are needed by autoconfig */
        info->config.rx_trigger = rx_trigger;
        info->config.tx_trigger = tx_trigger;

        i = 0;
        offset = 0;

        do {
                info->port = esp[i] + offset;
                info->irq = irq[i];
                info->line = (i * 8) + (offset / 8);

                if (!autoconfig(info, &region_start)) {
                        i++;
                        offset = 0;
                        continue;
                }

                info->custom_divisor = (divisor[i] >> (offset / 2)) & 0xf;
                info->flags = STD_COM_FLAGS;
                if (info->custom_divisor)
                        info->flags |= ASYNC_SPD_CUST;
                info->magic = ESP_MAGIC;
                info->close_delay = 5*HZ/10;
                info->closing_wait = 30*HZ;
                info->tqueue.routine = do_softint;
                info->tqueue.data = info;
                info->tqueue_hangup.routine = do_serial_hangup;
                info->tqueue_hangup.data = info;
                info->callout_termios = esp_callout_driver.init_termios;
                info->normal_termios = esp_driver.init_termios;
                info->config.rx_timeout = rx_timeout;
                info->config.flow_on = flow_on;
                info->config.flow_off = flow_off;
                info->config.pio_threshold = pio_threshold;
                info->next_port = ports;
                init_waitqueue_head(&info->open_wait);
                init_waitqueue_head(&info->close_wait);
                init_waitqueue_head(&info->delta_msr_wait);
                init_waitqueue_head(&info->break_wait);
                ports = info;
                printk(KERN_INFO "ttyP%d at 0x%04x (irq = %d) is an ESP ",
                        info->line, info->port, info->irq);

                if (info->line % 8) {
                        printk("secondary port\n");
                        /* 8 port cards can't do DMA */
                        info->stat_flags |= ESP_STAT_NEVER_DMA;

                        if (last_primary)
                                last_primary->stat_flags |= ESP_STAT_NEVER_DMA;
                } else {
                        printk("primary port\n");
                        last_primary = info;
                        irq[i] = info->irq;
                }

                if (!dma)
                        info->stat_flags |= ESP_STAT_NEVER_DMA;

                info = kmalloc(sizeof(struct esp_struct), GFP_KERNEL);
                if (!info)
                {
                        printk(KERN_ERR "Couldn't allocate memory for esp serial device information\n"); 

                        /* allow use of the already detected ports */
                        return 0;
                }

                memset((void *)info, 0, sizeof(struct esp_struct));
                /* rx_trigger, tx_trigger are needed by autoconfig */
                info->config.rx_trigger = rx_trigger;
                info->config.tx_trigger = tx_trigger;

                if (offset == 56) {
                        i++;
                        offset = 0;
                } else {
                        offset += 8;
                }
        } while (i < NR_PRIMARY);

        /* free the last port memory allocation */
        kfree(info);

        return 0;
}

static void __exit espserial_exit(void) 
{
        unsigned long flags;
        int e1, e2;
        unsigned int region_start, region_end;
        struct esp_struct *temp_async;
        struct esp_pio_buffer *pio_buf;

        /* printk("Unloading %s: version %s\n", serial_name, serial_version); */
        save_flags(flags);
        cli();
        remove_bh(ESP_BH);
        if ((e1 = tty_unregister_driver(&esp_driver)))
                printk("SERIAL: failed to unregister serial driver (%d)\n",
                       e1);
        if ((e2 = tty_unregister_driver(&esp_callout_driver)))
                printk("SERIAL: failed to unregister callout driver (%d)\n", 
                       e2);
        restore_flags(flags);

        while (ports) {
                if (ports->port) {
                        region_start = region_end = ports->port;
                        temp_async = ports;

                        while (temp_async) {
                                if ((region_start - temp_async->port) == 8) {
                                        region_start = temp_async->port;
                                        temp_async->port = 0;
                                        temp_async = ports;
                                } else if ((temp_async->port - region_end)
                                           == 8) {
                                        region_end = temp_async->port;
                                        temp_async->port = 0;
                                        temp_async = ports;
                                } else
                                        temp_async = temp_async->next_port;
                        }
                        
                        release_region(region_start,
                                       region_end - region_start + 8);
                }

                temp_async = ports->next_port;
                kfree(ports);
                ports = temp_async;
        }

        if (dma_buffer)
                free_pages((unsigned long)dma_buffer,
                        get_order(DMA_BUFFER_SZ));

        if (tmp_buf)
                free_page((unsigned long)tmp_buf);

        while (free_pio_buf) {
                pio_buf = free_pio_buf->next;
                kfree(free_pio_buf);
                free_pio_buf = pio_buf;
        }
}

module_init(espserial_init);
module_exit(espserial_exit);