text: /*
   *  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 Anh�pl 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 <asm/system.h>
  #include <asm/io.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 */
  #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
  	 */
  #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;
  
  	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;
  
  	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);
  
  	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 = 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);
  		put_tty_driver(esp_driver);
  		return 1;
  	}
  
  	memset((void *)info, 0, sizeof(struct esp_struct));
  	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 = 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) 
  {
  	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);
  