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esp.c

/*
 *  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 <linux/delay.h>
#include <linux/bitops.h>

#include <asm/system.h>
#include <asm/io.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 */
#define REGION_SIZE 8   /* size of io region to request */

/* 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_param_array(irq, int, NULL, 0);
module_param_array(divisor, uint, NULL, 0);
module_param(dma, uint, 0);
module_param(rx_trigger, uint, 0);
module_param(tx_trigger, uint, 0);
module_param(flow_off, uint, 0);
module_param(flow_on, uint, 0);
module_param(rx_timeout, uint, 0);
module_param(pio_threshold, uint, 0);

/* 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 struct tty_driver *esp_driver;

/* serial subtype definitions */
#define SERIAL_TYPE_NORMAL    1

/*
 * 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

#if defined(MODULE) && defined(SERIAL_DEBUG_MCOUNT)
#define DBG_CNT(s) printk("(%s): [%x] refc=%d, serc=%d, ttyc=%d -> %s\n", \
 tty->name, (info->flags), serial_driver.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 inline int serial_paranoia_check(struct esp_struct *info,
                              char *name, 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, name, routine);
            return 1;
      }
      if (info->magic != ESP_MAGIC) {
            printk(badmagic, name, 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->name, "rs_stop"))
            return;

      spin_lock_irqsave(&info->lock, flags);
      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);
      }
      spin_unlock_irqrestore(&info->lock, 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->name, "rs_start"))
            return;
      
      spin_lock_irqsave(&info->lock, flags);
      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);
      }
      spin_unlock_irqrestore(&info->lock, 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;
      schedule_work(&info->tqueue);
}

static DEFINE_SPINLOCK(pio_lock);

static inline struct esp_pio_buffer *get_pio_buffer(void)
{
      struct esp_pio_buffer *buf;
      unsigned long flags;

      spin_lock_irqsave(&pio_lock, flags);
      if (free_pio_buf) {
            buf = free_pio_buf;
            free_pio_buf = buf->next;
      } else {
            buf = kmalloc(sizeof(struct esp_pio_buffer), GFP_ATOMIC);
      }
      spin_unlock_irqrestore(&pio_lock, flags);
      return buf;
}

static inline void release_pio_buffer(struct esp_pio_buffer *buf)
{
      unsigned long flags;
      spin_lock_irqsave(&pio_lock, flags);
      buf->next = free_pio_buf;
      free_pio_buf = buf;
      spin_unlock_irqrestore(&pio_lock, flags);
}

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;
      }

      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;
      }

      /* 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)) {
                  int flag = 0;

                  if (err_buf->data[i] & 0x04) {
                        flag = TTY_BREAK;
                        if (info->flags & ASYNC_SAK)
                              do_SAK(tty);
                  }
                  else if (err_buf->data[i] & 0x02)
                        flag = TTY_FRAME;
                  else if (err_buf->data[i] & 0x01)
                        flag = TTY_PARITY;
                  tty_insert_flip_char(tty, pio_buf->data[i], flag);
            }
      }

      tty_schedule_flip(tty);

      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, isa_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;

      if (num_bytes > 0) {
            tty_insert_flip_string(tty, dma_buffer, num_bytes - 1);

            status &= (0x1c & info->read_status_mask);
            
            /* Is the status significant or do we throw the last byte ? */
            if (!(status & info->ignore_status_mask)) {
                  int statflag = 0;

                  if (status & 0x10) {
                        statflag = TTY_BREAK;
                        (info->icount.brk)++;
                        if (info->flags & ASYNC_SAK)
                              do_SAK(tty);
                  } else if (status & 0x08) {
                        statflag = TTY_FRAME;
                        (info->icount.frame)++;
                  }
                  else if (status & 0x04) {
                        statflag = TTY_PARITY;
                        (info->icount.parity)++;
                  }
                  tty_insert_flip_char(tty, dma_buffer[num_bytes - 1], statflag);
            }
            tty_schedule_flip(tty);
      }

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

/* Caller must hold info->lock */

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);

            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]);

            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);
}

/* Caller must hold info->lock */
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, isa_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, isa_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 {
#ifdef SERIAL_DEBUG_OPEN
                  printk("scheduling hangup...");
#endif
                  schedule_work(&info->tqueue_hangup);
            }
      }
}

/*
 * This is the serial driver's interrupt routine
 */
static irqreturn_t rs_interrupt_single(int irq, void *dev_id)
{
      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);

      spin_lock(&info->lock);
      
      if (!info->tty) {
            spin_unlock(&info->lock);
            return IRQ_NONE;
      }

      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);

            num_bytes = tty_buffer_request_room(info->tty, num_bytes);

            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
      spin_unlock(&info->lock);
      return IRQ_HANDLED;
}

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

static void do_softint(struct work_struct *work)
{
      struct esp_struct *info =
            container_of(work, struct esp_struct, tqueue);
      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(struct work_struct *work)
{
      struct esp_struct *info =
            container_of(work, struct esp_struct, tqueue_hangup);
      struct tty_struct *tty;
      
      tty = info->tty;
      if (tty)
            tty_hangup(tty);
}

/*
 * ---------------------------------------------------------------
 * 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.
 *
 * Caller should hold lock
 * ---------------------------------------------------------------
 */

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;

        spin_lock_irqsave(&info->lock, flags);

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

      if (!info->xmit_buf) {
            info->xmit_buf = (unsigned char *)get_zeroed_page(GFP_ATOMIC);
            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;

      spin_unlock_irqrestore(&info->lock, flags);

      /*
       * Allocate the IRQ
       */

      retval = request_irq(info->irq, rs_interrupt_single, IRQF_SHARED,
                       "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_unlocked;
      }

      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 = NULL;
                  info->stat_flags |= ESP_STAT_USE_PIO;
            }
                  
      }

      info->MCR = UART_MCR_DTR | UART_MCR_RTS | UART_MCR_OUT2;

      spin_lock_irqsave(&info->lock, flags);
      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;
      spin_unlock_irqrestore(&info->lock, flags);

      /*
       * 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;
      return 0;

out:
      spin_unlock_irqrestore(&info->lock, flags);
out_unlocked:
      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
      
      spin_lock_irqsave(&info->lock, flags);
      /*
       * 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 */
      /* DMA lock is higher priority always */
      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 = NULL;
            }           
      }

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

      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;
      spin_unlock_irqrestore(&info->lock, 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
       */
      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;

      spin_lock_irqsave(&info->lock, flags);
      /* 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);

      spin_unlock_irqrestore(&info->lock, 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->name, "rs_put_char"))
            return;

      if (!info->xmit_buf)
            return;

      spin_lock_irqsave(&info->lock, flags);
      if (info->xmit_cnt < ESP_XMIT_SIZE - 1) {
            info->xmit_buf[info->xmit_head++] = ch;
            info->xmit_head &= ESP_XMIT_SIZE-1;
            info->xmit_cnt++;
      }
      spin_unlock_irqrestore(&info->lock, 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->name, "rs_flush_chars"))
            return;

      spin_lock_irqsave(&info->lock, flags);

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

      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);
      }
out:
      spin_unlock_irqrestore(&info->lock, flags);
}

static int rs_write(struct tty_struct * tty,
                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->name, "rs_write"))
            return 0;

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

            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;
      }

      spin_lock_irqsave(&info->lock, flags);

      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);
      }

      spin_unlock_irqrestore(&info->lock, flags);
      return ret;
}

static int rs_write_room(struct tty_struct *tty)
{
      struct esp_struct *info = (struct esp_struct *)tty->driver_data;
      int   ret;
      unsigned long flags;
                        
      if (serial_paranoia_check(info, tty->name, "rs_write_room"))
            return 0;

      spin_lock_irqsave(&info->lock, flags);

      ret = ESP_XMIT_SIZE - info->xmit_cnt - 1;
      if (ret < 0)
            ret = 0;
      spin_unlock_irqrestore(&info->lock, flags);
      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->name, "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;
      unsigned long flags;
                        
      if (serial_paranoia_check(info, tty->name, "rs_flush_buffer"))
            return;
      spin_lock_irqsave(&info->lock, flags);
      info->xmit_cnt = info->xmit_head = info->xmit_tail = 0;
      spin_unlock_irqrestore(&info->lock, flags);
      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;
      unsigned long flags;
#ifdef SERIAL_DEBUG_THROTTLE
      char  buf[64];
      
      printk("throttle %s: %d....\n", tty_name(tty, buf),
             tty->ldisc.chars_in_buffer(tty));
#endif

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

      spin_lock_irqsave(&info->lock, flags);
      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);
      spin_unlock_irqrestore(&info->lock, flags);
}

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

      if (serial_paranoia_check(info, tty->name, "rs_unthrottle"))
            return;
      
      spin_lock_irqsave(&info->lock, flags);
      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);
      spin_unlock_irqrestore(&info->lock, flags);
}

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

static int get_serial_info(struct esp_struct * info,
                     struct serial_struct __user *retinfo)
{
      struct serial_struct tmp;
  
      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 __user *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 __user *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 __user * new_info)
{
      struct hayes_esp_config new_config;
      unsigned int change_dma;
      int retval = 0;
      struct esp_struct *current_async;
      unsigned long flags;

      /* 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 */

                  spin_lock_irqsave(&info->lock, flags);
                  current_async = ports;

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

                  shutdown(info);
                  spin_lock_irqsave(&info->lock, flags);
                  info->stat_flags |= ESP_STAT_NEVER_DMA;
                  esp_basic_init(info);
                  spin_unlock_irqrestore(&info->lock, flags);
            }
      }

      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;

            spin_lock_irqsave(&info->lock, flags);
            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);
            spin_unlock_irqrestore(&info->lock, 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;
            spin_lock_irqsave(&info->lock, flags);
            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);
            spin_unlock_irqrestore(&info->lock, flags);
      }

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

            info->config.rx_timeout = new_config.rx_timeout;
            spin_lock_irqsave(&info->lock, flags);

            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);
            }

            spin_unlock_irqrestore(&info->lock, 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 __user *value)
{
      unsigned char status;
      unsigned int result;
      unsigned long flags;

      spin_lock_irqsave(&info->lock, flags);
      serial_out(info, UART_ESI_CMD1, ESI_GET_UART_STAT);
      status = serial_in(info, UART_ESI_STAT1);
      spin_unlock_irqrestore(&info->lock, flags);
      result = ((status & UART_LSR_TEMT) ? TIOCSER_TEMT : 0);
      return put_user(result,value);
}


static int esp_tiocmget(struct tty_struct *tty, struct file *file)
{
      struct esp_struct * info = (struct esp_struct *)tty->driver_data;
      unsigned char control, status;
      unsigned long flags;

      if (serial_paranoia_check(info, tty->name, __FUNCTION__))
            return -ENODEV;
      if (tty->flags & (1 << TTY_IO_ERROR))
            return -EIO;

      control = info->MCR;

      spin_lock_irqsave(&info->lock, flags);
      serial_out(info, UART_ESI_CMD1, ESI_GET_UART_STAT);
      status = serial_in(info, UART_ESI_STAT2);
      spin_unlock_irqrestore(&info->lock, flags);

      return    ((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);
}

static int esp_tiocmset(struct tty_struct *tty, struct file *file,
                  unsigned int set, unsigned int clear)
{
      struct esp_struct * info = (struct esp_struct *)tty->driver_data;
      unsigned long flags;

      if (serial_paranoia_check(info, tty->name, __FUNCTION__))
            return -ENODEV;
      if (tty->flags & (1 << TTY_IO_ERROR))
            return -EIO;

      spin_lock_irqsave(&info->lock, flags);

      if (set & TIOCM_RTS)
            info->MCR |= UART_MCR_RTS;
      if (set & TIOCM_DTR)
            info->MCR |= UART_MCR_DTR;

      if (clear & TIOCM_RTS)
            info->MCR &= ~UART_MCR_RTS;
      if (clear & TIOCM_DTR)
            info->MCR &= ~UART_MCR_DTR;

      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);

      spin_unlock_irqrestore(&info->lock, flags);
      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->name, "esp_break"))
            return;

      if (break_state == -1) {
            spin_lock_irqsave(&info->lock, flags);
            serial_out(info, UART_ESI_CMD1, ESI_ISSUE_BREAK);
            serial_out(info, UART_ESI_CMD2, 0x01);
            spin_unlock_irqrestore(&info->lock, flags);

            /* FIXME - new style wait needed here */
            interruptible_sleep_on(&info->break_wait);
      } else {
            spin_lock_irqsave(&info->lock, flags);
            serial_out(info, UART_ESI_CMD1, ESI_ISSUE_BREAK);
            serial_out(info, UART_ESI_CMD2, 0x00);
            spin_unlock_irqrestore(&info->lock, 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 __user *p_cuser;  /* user space */
      void __user *argp = (void __user *)arg;
      unsigned long flags;

      if (serial_paranoia_check(info, tty->name, "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 TIOCGSERIAL:
                  return get_serial_info(info, argp);
            case TIOCSSERIAL:
                  return set_serial_info(info, argp);
            case TIOCSERCONFIG:
                  /* do not reconfigure after initial configuration */
                  return 0;

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

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

            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:
                  spin_lock_irqsave(&info->lock, flags);
                  cprev = info->icount;   /* note the counters on entry */
                  spin_unlock_irqrestore(&info->lock, flags);
                  while (1) {
                        /* FIXME: convert to new style wakeup */
                        interruptible_sleep_on(&info->delta_msr_wait);
                        /* see if a signal did it */
                        if (signal_pending(current))
                              return -ERESTARTSYS;
                        spin_lock_irqsave(&info->lock, flags);
                        cnow = info->icount;    /* atomic copy */
                        spin_unlock_irqrestore(&info->lock, flags);
                        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:
                  spin_lock_irqsave(&info->lock, flags);
                  cnow = info->icount;
                  spin_unlock_irqrestore(&info->lock, flags);
                  p_cuser = argp;
                  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, argp);
      case TIOCSHAYESESP:
            return set_esp_config(info, argp);

            default:
                  return -ENOIOCTLCMD;
            }
      return 0;
}

static void rs_set_termios(struct tty_struct *tty, struct ktermios *old_termios)
{
      struct esp_struct *info = (struct esp_struct *)tty->driver_data;
      unsigned long flags;

      change_speed(info);

      spin_lock_irqsave(&info->lock, flags);

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

      /* 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);
            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);
      }

      spin_unlock_irqrestore(&info->lock, flags);

      /* Handle turning of CRTSCTS */
      if ((old_termios->c_cflag & CRTSCTS) &&
          !(tty->termios->c_cflag & CRTSCTS)) {
            rs_start(tty);
      }
}

/*
 * ------------------------------------------------------------
 * 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->name, "rs_close"))
            return;
      
      spin_lock_irqsave(&info->lock, flags);
      
      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;

      spin_unlock_irqrestore(&info->lock, flags);
      /*
       * 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) {

            spin_lock_irqsave(&info->lock, flags);
            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);

            spin_unlock_irqrestore(&info->lock, flags);

            /*
             * 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 = NULL;

      if (info->blocked_open) {
            if (info->close_delay) {
                  msleep_interruptible(jiffies_to_msecs(info->close_delay));
            }
            wake_up_interruptible(&info->open_wait);
      }
      info->flags &= ~(ASYNC_NORMAL_ACTIVE|ASYNC_CLOSING);
      wake_up_interruptible(&info->close_wait);
      return;

out:
      spin_unlock_irqrestore(&info->lock, 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->name, "rs_wait_until_sent"))
            return;

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

      if (!char_time)
            char_time = 1;

      spin_lock_irqsave(&info->lock, flags);
      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)) {

            spin_unlock_irqrestore(&info->lock, flags);
            msleep_interruptible(jiffies_to_msecs(char_time));

            if (signal_pending(current))
                  break;

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

            spin_lock_irqsave(&info->lock, flags);
            serial_out(info, UART_ESI_CMD1, ESI_NO_COMMAND);
            serial_out(info, UART_ESI_CMD1, ESI_GET_TX_AVAIL);
      }
      spin_unlock_irqrestore(&info->lock, 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->name, "esp_hangup"))
            return;
      
      rs_flush_buffer(tty);
      shutdown(info);
      info->event = 0;
      info->count = 0;
      info->flags &= ~ASYNC_NORMAL_ACTIVE;
      info->tty = NULL;
      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 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))) {
            info->flags |= ASYNC_NORMAL_ACTIVE;
            return 0;
      }

      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
      spin_lock_irqsave(&info->lock, flags);
      if (!tty_hung_up_p(filp)) 
            info->count--;
      info->blocked_open++;
      while (1) {
            if ((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);
            }
            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_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
            spin_unlock_irqrestore(&info->lock, flags);
            schedule();
            spin_lock_irqsave(&info->lock, flags);
      }
      set_current_state(TASK_RUNNING);
      remove_wait_queue(&info->open_wait, &wait);
      if (!tty_hung_up_p(filp))
            info->count++;
      info->blocked_open--;
      spin_unlock_irqrestore(&info->lock, flags);
#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;
      unsigned long           flags;

      line = tty->index;
      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->name, "esp_open");
            return -ENODEV;
      }

#ifdef SERIAL_DEBUG_OPEN
      printk("esp_open %s, count = %d\n", tty->name, info->count);
#endif
      spin_lock_irqsave(&info->lock, flags);
      info->count++;
      tty->driver_data = info;
      info->tty = tty;

      spin_unlock_irqrestore(&info->lock, flags);
      
      /*
       * 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;
      }

#ifdef SERIAL_DEBUG_OPEN
      printk("esp_open %s successful...", tty->name);
#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 port_detected = 0;
      unsigned long flags;

      if (!request_region(info->port, REGION_SIZE, "esp serial"))
            return -EIO;

      spin_lock_irqsave(&info->lock, flags);
      /*
       * Check for ESP card
       */

      if (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;
                  }


                  /* 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);
            }
      }
      if (!port_detected)
            release_region(info->port, REGION_SIZE);

      spin_unlock_irqrestore(&info->lock, flags);
      return (port_detected);
}

static const struct tty_operations esp_ops = {
      .open = esp_open,
      .close = rs_close,
      .write = rs_write,
      .put_char = rs_put_char,
      .flush_chars = rs_flush_chars,
      .write_room = rs_write_room,
      .chars_in_buffer = rs_chars_in_buffer,
      .flush_buffer = rs_flush_buffer,
      .ioctl = rs_ioctl,
      .throttle = rs_throttle,
      .unthrottle = rs_unthrottle,
      .set_termios = rs_set_termios,
      .stop = rs_stop,
      .start = rs_start,
      .hangup = esp_hangup,
      .break_ctl = esp_break,
      .wait_until_sent = rs_wait_until_sent,
      .tiocmget = esp_tiocmget,
      .tiocmset = esp_tiocmset,
};

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

      esp_driver = alloc_tty_driver(NR_PORTS);
      if (!esp_driver)
            return -ENOMEM;
      
      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 */
      
      esp_driver->owner = THIS_MODULE;
      esp_driver->name = "ttyP";
      esp_driver->major = ESP_IN_MAJOR;
      esp_driver->minor_start = 0;
      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;
      tty_set_operations(esp_driver, &esp_ops);
      if (tty_register_driver(esp_driver))
      {
            printk(KERN_ERR "Couldn't register esp serial driver");
            put_tty_driver(esp_driver);
            return 1;
      }

      info = kzalloc(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);
            put_tty_driver(esp_driver);
            return 1;
      }

      spin_lock_init(&info->lock);
      /* 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)) {
                  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;
            INIT_WORK(&info->tqueue, do_softint);
            INIT_WORK(&info->tqueue_hangup, do_serial_hangup);
            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 = kzalloc(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;
            }

            /* 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) 
{
      int e1;
      struct esp_struct *temp_async;
      struct esp_pio_buffer *pio_buf;

      /* printk("Unloading %s: version %s\n", serial_name, serial_version); */
      if ((e1 = tty_unregister_driver(esp_driver)))
            printk("SERIAL: failed to unregister serial driver (%d)\n",
                   e1);
      put_tty_driver(esp_driver);

      while (ports) {
            if (ports->port) {
                  release_region(ports->port, REGION_SIZE);
            }
            temp_async = ports->next_port;
            kfree(ports);
            ports = temp_async;
      }

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

      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);

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