// SPDX-License-Identifier: GPL-2.0+

  /*

   *	Original driver code supplied by Multi-Tech
   *
   *	Changes

   *	1/9/98	alan@lxorguk.ukuu.org.uk
   *					Merge to 2.0.x kernel tree

   *					Obtain and use official major/minors
   *					Loader switched to a misc device
   *					(fixed range check bug as a side effect)
   *					Printk clean up

   *	9/12/98	alan@lxorguk.ukuu.org.uk
   *					Rough port to 2.1.x

   *
   *	10/6/99 sameer			Merged the ISA and PCI drivers to
   *					a new unified driver.
   *
   *	3/9/99	sameer			Added support for ISI4616 cards.
   *
   *	16/9/99	sameer			We do not force RTS low anymore.

   *					This is to prevent the firmware

   *					from getting confused.
   *
   *	26/10/99 sameer			Cosmetic changes:The driver now
   *					dumps the Port Count information
   *					along with I/O address and IRQ.
   *
   *	13/12/99 sameer			Fixed the problem with IRQ sharing.
   *
   *	10/5/00  sameer			Fixed isicom_shutdown_board()
   *					to not lower DTR on all the ports

   *					when the last port on the card is

   *					closed.
   *
   *	10/5/00  sameer			Signal mask setup command added

   *					to  isicom_setup_port and

   *					isicom_shutdown_port.
   *
   *	24/5/00  sameer			The driver is now SMP aware.

   *
   *

   *	27/11/00 Vinayak P Risbud	Fixed the Driver Crash Problem

   *
   *

   *	03/01/01  anil .s		Added support for resetting the
   *					internal modems on ISI cards.
   *
   *	08/02/01  anil .s		Upgraded the driver for kernel
   *					2.4.x
   *

   *	11/04/01  Kevin			Fixed firmware load problem with

   *					ISIHP-4X card

   *

   *	30/04/01  anil .s		Fixed the remote login through
   *					ISI port problem. Now the link
   *					does not go down before password
   *					prompt.
   *
   *	03/05/01  anil .s		Fixed the problem with IRQ sharing
   *					among ISI-PCI cards.
   *
   *	03/05/01  anil .s		Added support to display the version

   *					info during insmod as well as module

   *					listing by lsmod.

   *

   *	10/05/01  anil .s		Done the modifications to the source
   *					file and Install script so that the
   *					same installation can be used for
   *					2.2.x and 2.4.x kernel.
   *
   *	06/06/01  anil .s		Now we drop both dtr and rts during
   *					shutdown_port as well as raise them
   *					during isicom_config_port.

   *

   *	09/06/01 acme@conectiva.com.br	use capable, not suser, do
   *					restore_flags on failure in
   *					isicom_send_break, verify put_user
   *					result
   *

   *	11/02/03  ranjeeth		Added support for 230 Kbps and 460 Kbps
   *					Baud index extended to 21
   *
   *	20/03/03  ranjeeth		Made to work for Linux Advanced server.
   *					Taken care of license warning.
   *
   *	10/12/03  Ravindra		Made to work for Fedora Core 1 of

   *					Red Hat Distribution
   *
   *	06/01/05  Alan Cox 		Merged the ISI and base kernel strands
   *					into a single 2.6 driver
   *
   *	***********************************************************
   *

   *	To use this driver you also need the support package. You

   *	can find this in RPM format on
   *		ftp://ftp.linux.org.uk/pub/linux/alan

   *

   *	You can find the original tools for this direct from Multitech
   *		ftp://ftp.multitech.com/ISI-Cards/
   *

   *	Having installed the cards the module options (/etc/modprobe.d/)

   *
   *	options isicom   io=card1,card2,card3,card4 irq=card1,card2,card3,card4
   *
   *	Omit those entries for boards you don't have installed.
   *
   *	TODO

   *		Merge testing
   *		64-bit verification
   */

  #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt

  #include <linux/module.h>

  #include <linux/firmware.h>

  #include <linux/kernel.h>
  #include <linux/tty.h>

  #include <linux/tty_flip.h>

  #include <linux/termios.h>
  #include <linux/fs.h>
  #include <linux/sched.h>
  #include <linux/serial.h>
  #include <linux/mm.h>

  #include <linux/interrupt.h>
  #include <linux/timer.h>
  #include <linux/delay.h>
  #include <linux/ioport.h>

  #include <linux/slab.h>

  #include <linux/uaccess.h>
  #include <linux/io.h>

  
  #include <linux/pci.h>
  
  #include <linux/isicom.h>

  #define InterruptTheCard(base) outw(0, (base) + 0xc)
  #define ClearInterrupt(base) inw((base) + 0x0a)
  
  #ifdef DEBUG

  #define isicom_paranoia_check(a, b, c) __isicom_paranoia_check((a), (b), (c))
  #else

  #define isicom_paranoia_check(a, b, c) 0
  #endif

  static int isicom_probe(struct pci_dev *, const struct pci_device_id *);

  static void isicom_remove(struct pci_dev *);

  static const struct pci_device_id isicom_pci_tbl[] = {

  	{ PCI_DEVICE(VENDOR_ID, 0x2028) },
  	{ PCI_DEVICE(VENDOR_ID, 0x2051) },
  	{ PCI_DEVICE(VENDOR_ID, 0x2052) },
  	{ PCI_DEVICE(VENDOR_ID, 0x2053) },
  	{ PCI_DEVICE(VENDOR_ID, 0x2054) },
  	{ PCI_DEVICE(VENDOR_ID, 0x2055) },
  	{ PCI_DEVICE(VENDOR_ID, 0x2056) },
  	{ PCI_DEVICE(VENDOR_ID, 0x2057) },
  	{ PCI_DEVICE(VENDOR_ID, 0x2058) },

  	{ 0 }
  };
  MODULE_DEVICE_TABLE(pci, isicom_pci_tbl);

  static struct pci_driver isicom_driver = {
  	.name		= "isicom",
  	.id_table	= isicom_pci_tbl,
  	.probe		= isicom_probe,

  	.remove		= isicom_remove

  };

  static int prev_card = 3;	/*	start servicing isi_card[0]	*/
  static struct tty_driver *isicom_normal;

  static void isicom_tx(struct timer_list *unused);

  static void isicom_start(struct tty_struct *tty);

  static DEFINE_TIMER(tx, isicom_tx);

  /*   baud index mappings from linux defns to isi */
  
  static signed char linuxb_to_isib[] = {

  	-1, 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 11, 13, 15, 16, 17, 18, 19, 20, 21

  };
  
  struct	isi_board {

  	unsigned long		base;

  	int			irq;

  	unsigned char		port_count;
  	unsigned short		status;

  	unsigned short		port_status; /* each bit for each port */

  	unsigned short		shift_count;

  	struct isi_port		*ports;

  	signed char		count;

  	spinlock_t		card_lock; /* Card wide lock 11/5/00 -sameer */
  	unsigned long		flags;

  	unsigned int		index;

  };
  
  struct	isi_port {
  	unsigned short		magic;

  	struct tty_port		port;

  	u16			channel;
  	u16			status;

  	struct isi_board	*card;

  	unsigned char		*xmit_buf;

  	int			xmit_head;
  	int			xmit_tail;
  	int			xmit_cnt;
  };
  
  static struct isi_board isi_card[BOARD_COUNT];
  static struct isi_port  isi_ports[PORT_COUNT];
  
  /*
   *	Locking functions for card level locking. We need to own both
   *	the kernel lock for the card and have the card in a position that
   *	it wants to talk.
   */

  static int WaitTillCardIsFree(unsigned long base)

  {
  	unsigned int count = 0;

  
  	while (!(inw(base + 0xe) & 0x1) && count++ < 100)

  		mdelay(1);

  
  	return !(inw(base + 0xe) & 0x1);
  }

  static int lock_card(struct isi_board *card)
  {

  	unsigned long base = card->base;

  	unsigned int retries, a;

  	for (retries = 0; retries < 10; retries++) {

  		spin_lock_irqsave(&card->card_lock, card->flags);

  		for (a = 0; a < 10; a++) {
  			if (inw(base + 0xe) & 0x1)
  				return 1;
  			udelay(10);

  		}

  		spin_unlock_irqrestore(&card->card_lock, card->flags);
  		msleep(10);

  	}

  	pr_warn("Failed to lock Card (0x%lx)
  ", card->base);

  	return 0;	/* Failed to acquire the card! */

  }

  static void unlock_card(struct isi_board *card)
  {
  	spin_unlock_irqrestore(&card->card_lock, card->flags);
  }
  
  /*
   *  ISI Card specific ops ...
   */

  /* card->lock HAS to be held */

  static void raise_dtr(struct isi_port *port)

  {

  	struct isi_board *card = port->card;

  	unsigned long base = card->base;
  	u16 channel = port->channel;

  	if (WaitTillCardIsFree(base))

  		return;

  	outw(0x8000 | (channel << card->shift_count) | 0x02, base);

  	outw(0x0504, base);
  	InterruptTheCard(base);
  	port->status |= ISI_DTR;

  }

  /* card->lock HAS to be held */

  static void drop_dtr(struct isi_port *port)

  {
  	struct isi_board *card = port->card;

  	unsigned long base = card->base;
  	u16 channel = port->channel;

  	if (WaitTillCardIsFree(base))

  		return;

  	outw(0x8000 | (channel << card->shift_count) | 0x02, base);

  	outw(0x0404, base);

  	InterruptTheCard(base);

  	port->status &= ~ISI_DTR;

  }

  /* card->lock HAS to be held */

  static inline void raise_rts(struct isi_port *port)

  {

  	struct isi_board *card = port->card;

  	unsigned long base = card->base;
  	u16 channel = port->channel;

  	if (WaitTillCardIsFree(base))

  		return;

  	outw(0x8000 | (channel << card->shift_count) | 0x02, base);

  	outw(0x0a04, base);

  	InterruptTheCard(base);

  	port->status |= ISI_RTS;

  }

  
  /* card->lock HAS to be held */

  static inline void drop_rts(struct isi_port *port)

  {

  	struct isi_board *card = port->card;

  	unsigned long base = card->base;
  	u16 channel = port->channel;

  	if (WaitTillCardIsFree(base))

  		return;

  	outw(0x8000 | (channel << card->shift_count) | 0x02, base);

  	outw(0x0804, base);

  	InterruptTheCard(base);

  	port->status &= ~ISI_RTS;

  }

  /* card->lock MUST NOT be held */

  static void isicom_dtr_rts(struct tty_port *port, int on)

  {

  	struct isi_port *ip = container_of(port, struct isi_port, port);
  	struct isi_board *card = ip->card;

  	unsigned long base = card->base;

  	u16 channel = ip->channel;

  
  	if (!lock_card(card))
  		return;

  	if (on) {
  		outw(0x8000 | (channel << card->shift_count) | 0x02, base);
  		outw(0x0f04, base);
  		InterruptTheCard(base);
  		ip->status |= (ISI_DTR | ISI_RTS);
  	} else {
  		outw(0x8000 | (channel << card->shift_count) | 0x02, base);
  		outw(0x0C04, base);
  		InterruptTheCard(base);
  		ip->status &= ~(ISI_DTR | ISI_RTS);
  	}

  	unlock_card(card);
  }

  /* card->lock HAS to be held */

  static void drop_dtr_rts(struct isi_port *port)

  {

  	struct isi_board *card = port->card;

  	unsigned long base = card->base;
  	u16 channel = port->channel;

  	if (WaitTillCardIsFree(base))

  		return;

  	outw(0x8000 | (channel << card->shift_count) | 0x02, base);

  	outw(0x0c04, base);

  	InterruptTheCard(base);

  	port->status &= ~(ISI_RTS | ISI_DTR);

  }

  /*
   *	ISICOM Driver specific routines ...
   *
   */

  static inline int __isicom_paranoia_check(struct isi_port const *port,
  	char *name, const char *routine)

  {

  	if (!port) {

  		pr_warn("Warning: bad isicom magic for dev %s in %s
  ",
  			name, routine);

  		return 1;
  	}
  	if (port->magic != ISICOM_MAGIC) {

  		pr_warn("Warning: NULL isicom port for dev %s in %s
  ",
  			name, routine);

  		return 1;

  	}

  	return 0;
  }

  /*

   *	Transmitter.

   *
   *	We shovel data into the card buffers on a regular basis. The card
   *	will do the rest of the work for us.
   */

  static void isicom_tx(struct timer_list *unused)

  {

  	unsigned long flags, base;

  	unsigned int retries;

  	short count = (BOARD_COUNT-1), card;

  	short txcount, wrd, residue, word_count, cnt;

  	struct isi_port *port;
  	struct tty_struct *tty;

  	/*	find next active board	*/
  	card = (prev_card + 1) & 0x0003;

  	while (count-- > 0) {

  		if (isi_card[card].status & BOARD_ACTIVE)

  			break;

  		card = (card + 1) & 0x0003;

  	}
  	if (!(isi_card[card].status & BOARD_ACTIVE))
  		goto sched_again;

  	prev_card = card;

  	count = isi_card[card].port_count;
  	port = isi_card[card].ports;
  	base = isi_card[card].base;

  
  	spin_lock_irqsave(&isi_card[card].card_lock, flags);
  	for (retries = 0; retries < 100; retries++) {
  		if (inw(base + 0xe) & 0x1)
  			break;
  		udelay(2);
  	}
  	if (retries >= 100)
  		goto unlock;

  	tty = tty_port_tty_get(&port->port);
  	if (tty == NULL)
  		goto put_unlock;

  	for (; count > 0; count--, port++) {

  		/* port not active or tx disabled to force flow control */

  		if (!tty_port_initialized(&port->port) ||
  			!(port->status & ISI_TXOK))

  			continue;

  		txcount = min_t(short, TX_SIZE, port->xmit_cnt);

  		if (txcount <= 0 || tty->stopped || tty->hw_stopped)

  			continue;

  
  		if (!(inw(base + 0x02) & (1 << port->channel)))

  			continue;

  		pr_debug("txing %d bytes, port%d.
  ",
  			 txcount, port->channel + 1);

  		outw((port->channel << isi_card[card].shift_count) | txcount,
  			base);

  		residue = NO;

  		wrd = 0;

  		while (1) {

  			cnt = min_t(int, txcount, (SERIAL_XMIT_SIZE
  					- port->xmit_tail));

  			if (residue == YES) {
  				residue = NO;
  				if (cnt > 0) {

  					wrd |= (port->port.xmit_buf[port->xmit_tail]

  									<< 8);
  					port->xmit_tail = (port->xmit_tail + 1)
  						& (SERIAL_XMIT_SIZE - 1);

  					port->xmit_cnt--;
  					txcount--;
  					cnt--;

  					outw(wrd, base);

  				} else {

  					outw(wrd, base);
  					break;
  				}

  			}

  			if (cnt <= 0)
  				break;

  			word_count = cnt >> 1;

  			outsw(base, port->port.xmit_buf+port->xmit_tail, word_count);

  			port->xmit_tail = (port->xmit_tail
  				+ (word_count << 1)) & (SERIAL_XMIT_SIZE - 1);

  			txcount -= (word_count << 1);
  			port->xmit_cnt -= (word_count << 1);
  			if (cnt & 0x0001) {
  				residue = YES;

  				wrd = port->port.xmit_buf[port->xmit_tail];

  				port->xmit_tail = (port->xmit_tail + 1)
  					& (SERIAL_XMIT_SIZE - 1);

  				port->xmit_cnt--;
  				txcount--;
  			}
  		}
  
  		InterruptTheCard(base);
  		if (port->xmit_cnt <= 0)
  			port->status &= ~ISI_TXOK;
  		if (port->xmit_cnt <= WAKEUP_CHARS)

  			tty_wakeup(tty);

  	}

  put_unlock:
  	tty_kref_put(tty);

  unlock:
  	spin_unlock_irqrestore(&isi_card[card].card_lock, flags);

  	/*	schedule another tx for hopefully in about 10ms	*/
  sched_again:

  	mod_timer(&tx, jiffies + msecs_to_jiffies(10));

  }

  /*

   *	Main interrupt handler routine

   */

  static irqreturn_t isicom_interrupt(int irq, void *dev_id)

  {

  	struct isi_board *card = dev_id;

  	struct isi_port *port;
  	struct tty_struct *tty;

  	unsigned long base;
  	u16 header, word_count, count, channel;

  	short byte_count;

  	unsigned char *rp;

  	if (!card || !(card->status & FIRMWARE_LOADED))
  		return IRQ_NONE;

  	base = card->base;

  
  	/* did the card interrupt us? */
  	if (!(inw(base + 0x0e) & 0x02))
  		return IRQ_NONE;

  	spin_lock(&card->card_lock);

  	/*
  	 * disable any interrupts from the PCI card and lower the
  	 * interrupt line
  	 */
  	outw(0x8000, base+0x04);
  	ClearInterrupt(base);

  	inw(base);		/* get the dummy word out */
  	header = inw(base);
  	channel = (header & 0x7800) >> card->shift_count;
  	byte_count = header & 0xff;
  
  	if (channel + 1 > card->port_count) {

  		pr_warn("%s(0x%lx): %d(channel) > port_count
  ",
  			__func__, base, channel + 1);

  		outw(0x0000, base+0x04); /* enable interrupts */

  		spin_unlock(&card->card_lock);

  		return IRQ_HANDLED;

  	}
  	port = card->ports + channel;

  	if (!tty_port_initialized(&port->port)) {

  		outw(0x0000, base+0x04); /* enable interrupts */

  		spin_unlock(&card->card_lock);

  		return IRQ_HANDLED;

  	}

  	tty = tty_port_tty_get(&port->port);

  	if (tty == NULL) {

  		while (byte_count > 1) {

  			inw(base);
  			byte_count -= 2;
  		}
  		if (byte_count & 0x01)
  			inw(base);

  		outw(0x0000, base+0x04); /* enable interrupts */

  		spin_unlock(&card->card_lock);
  		return IRQ_HANDLED;
  	}

  	if (header & 0x8000) {		/* Status Packet */
  		header = inw(base);

  		switch (header & 0xff) {

  		case 0:	/* Change in EIA signals */

  			if (tty_port_check_carrier(&port->port)) {

  				if (port->status & ISI_DCD) {
  					if (!(header & ISI_DCD)) {
  					/* Carrier has been lost  */

  						pr_debug("%s: DCD->low.
  ",
  							 __func__);

  						port->status &= ~ISI_DCD;

  						tty_hangup(tty);

  					}

  				} else if (header & ISI_DCD) {
  				/* Carrier has been detected */

  					pr_debug("%s: DCD->high.
  ",
  						__func__);

  					port->status |= ISI_DCD;

  					wake_up_interruptible(&port->port.open_wait);

  				}

  			} else {

  				if (header & ISI_DCD)
  					port->status |= ISI_DCD;
  				else
  					port->status &= ~ISI_DCD;
  			}

  			if (tty_port_cts_enabled(&port->port)) {

  				if (tty->hw_stopped) {

  					if (header & ISI_CTS) {

  						tty->hw_stopped = 0;

  						/* start tx ing */

  						port->status |= (ISI_TXOK
  							| ISI_CTS);

  						tty_wakeup(tty);

  					}

  				} else if (!(header & ISI_CTS)) {

  					tty->hw_stopped = 1;

  					/* stop tx ing */
  					port->status &= ~(ISI_TXOK | ISI_CTS);

  				}

  			} else {

  				if (header & ISI_CTS)
  					port->status |= ISI_CTS;

  				else

  					port->status &= ~ISI_CTS;
  			}
  
  			if (header & ISI_DSR)
  				port->status |= ISI_DSR;
  			else
  				port->status &= ~ISI_DSR;
  
  			if (header & ISI_RI)
  				port->status |= ISI_RI;
  			else
  				port->status &= ~ISI_RI;
  
  			break;

  		case 1:	/* Received Break !!! */

  			tty_insert_flip_char(&port->port, 0, TTY_BREAK);

  			if (port->port.flags & ASYNC_SAK)

  				do_SAK(tty);

  			tty_flip_buffer_push(&port->port);

  			break;
  
  		case 2:	/* Statistics		 */

  			pr_debug("%s: stats!!!
  ", __func__);

  			break;
  
  		default:

  			pr_debug("%s: Unknown code in status packet.
  ",
  				 __func__);

  			break;
  		}

  	} else {				/* Data   Packet */

  		count = tty_prepare_flip_string(&port->port, &rp,
  				byte_count & ~1);

  		pr_debug("%s: Can rx %d of %d bytes.
  ",
  			 __func__, count, byte_count);

  		word_count = count >> 1;

  		insw(base, rp, word_count);

  		byte_count -= (word_count << 1);
  		if (count & 0x0001) {

  			tty_insert_flip_char(&port->port, inw(base) & 0xff,

  				TTY_NORMAL);

  			byte_count -= 2;

  		}

  		if (byte_count > 0) {

  			pr_debug("%s(0x%lx:%d): Flip buffer overflow! dropping bytes...
  ",
  				 __func__, base, channel + 1);

  		/* drain out unread xtra data */
  		while (byte_count > 0) {

  				inw(base);
  				byte_count -= 2;
  			}
  		}

  		tty_flip_buffer_push(&port->port);

  	}

  	outw(0x0000, base+0x04); /* enable interrupts */

  	spin_unlock(&card->card_lock);

  	tty_kref_put(tty);

  	return IRQ_HANDLED;

  }

  static void isicom_config_port(struct tty_struct *tty)

  {

  	struct isi_port *port = tty->driver_data;

  	struct isi_board *card = port->card;

  	unsigned long baud;

  	unsigned long base = card->base;
  	u16 channel_setup, channel = port->channel,
  		shift_count = card->shift_count;

  	unsigned char flow_ctrl;

  	/* FIXME: Switch to new tty baud API */

  	baud = C_BAUD(tty);
  	if (baud & CBAUDEX) {
  		baud &= ~CBAUDEX;

  		/*  if CBAUDEX bit is on and the baud is set to either 50 or 75
  		 *  then the card is programmed for 57.6Kbps or 115Kbps
  		 *  respectively.

  		 */

  		/* 1,2,3,4 => 57.6, 115.2, 230, 460 kbps resp. */
  		if (baud < 1 || baud > 4)

  			tty->termios.c_cflag &= ~CBAUDEX;

  		else
  			baud += 15;

  	}

  	if (baud == 15) {

  
  		/*  the ASYNC_SPD_HI and ASYNC_SPD_VHI options are set

  		 *  by the set_serial_info ioctl ... this is done by
  		 *  the 'setserial' utility.

  		 */

  		if ((port->port.flags & ASYNC_SPD_MASK) == ASYNC_SPD_HI)

  			baud++; /*  57.6 Kbps */

  		if ((port->port.flags & ASYNC_SPD_MASK) == ASYNC_SPD_VHI)

  			baud += 2; /*  115  Kbps */

  		if ((port->port.flags & ASYNC_SPD_MASK) == ASYNC_SPD_SHI)

  			baud += 3; /* 230 kbps*/

  		if ((port->port.flags & ASYNC_SPD_MASK) == ASYNC_SPD_WARP)

  			baud += 4; /* 460 kbps*/

  	}
  	if (linuxb_to_isib[baud] == -1) {
  		/* hang up */

  		drop_dtr(port);
  		return;

  	} else

  		raise_dtr(port);

  	if (WaitTillCardIsFree(base) == 0) {

  		outw(0x8000 | (channel << shift_count) | 0x03, base);

  		outw(linuxb_to_isib[baud] << 8 | 0x03, base);
  		channel_setup = 0;

  		switch (C_CSIZE(tty)) {

  		case CS5:
  			channel_setup |= ISICOM_CS5;
  			break;
  		case CS6:
  			channel_setup |= ISICOM_CS6;
  			break;
  		case CS7:
  			channel_setup |= ISICOM_CS7;
  			break;
  		case CS8:
  			channel_setup |= ISICOM_CS8;
  			break;

  		}

  		if (C_CSTOPB(tty))
  			channel_setup |= ISICOM_2SB;
  		if (C_PARENB(tty)) {
  			channel_setup |= ISICOM_EVPAR;
  			if (C_PARODD(tty))

  				channel_setup |= ISICOM_ODPAR;

  		}

  		outw(channel_setup, base);

  		InterruptTheCard(base);

  	}

  	tty_port_set_check_carrier(&port->port, !C_CLOCAL(tty));

  	/* flow control settings ...*/
  	flow_ctrl = 0;

  	tty_port_set_cts_flow(&port->port, C_CRTSCTS(tty));
  	if (C_CRTSCTS(tty))

  		flow_ctrl |= ISICOM_CTSRTS;

  	if (I_IXON(tty))

  		flow_ctrl |= ISICOM_RESPOND_XONXOFF;
  	if (I_IXOFF(tty))

  		flow_ctrl |= ISICOM_INITIATE_XONXOFF;

  	if (WaitTillCardIsFree(base) == 0) {

  		outw(0x8000 | (channel << shift_count) | 0x04, base);

  		outw(flow_ctrl << 8 | 0x05, base);
  		outw((STOP_CHAR(tty)) << 8 | (START_CHAR(tty)), base);
  		InterruptTheCard(base);

  	}

  	/*	rx enabled -> enable port for rx on the card	*/
  	if (C_CREAD(tty)) {
  		card->port_status |= (1 << channel);
  		outw(card->port_status, base + 0x02);
  	}
  }

  /* open et all */
  
  static inline void isicom_setup_board(struct isi_board *bp)

  {
  	int channel;

  	struct isi_port *port;

  	bp->count++;

  	if (!(bp->status & BOARD_INIT)) {
  		port = bp->ports;
  		for (channel = 0; channel < bp->port_count; channel++, port++)
  			drop_dtr_rts(port);
  	}
  	bp->status |= BOARD_ACTIVE | BOARD_INIT;

  }

  /* Activate and thus setup board are protected from races against shutdown
     by the tty_port mutex */

  static int isicom_activate(struct tty_port *tport, struct tty_struct *tty)

  {

  	struct isi_port *port = container_of(tport, struct isi_port, port);

  	struct isi_board *card = port->card;

  	unsigned long flags;

  	if (tty_port_alloc_xmit_buf(tport) < 0)

  		return -ENOMEM;

  
  	spin_lock_irqsave(&card->card_lock, flags);

  	isicom_setup_board(card);

  	port->xmit_cnt = port->xmit_head = port->xmit_tail = 0;

  	/*	discard any residual data	*/

  	if (WaitTillCardIsFree(card->base) == 0) {
  		outw(0x8000 | (port->channel << card->shift_count) | 0x02,
  				card->base);
  		outw(((ISICOM_KILLTX | ISICOM_KILLRX) << 8) | 0x06, card->base);
  		InterruptTheCard(card->base);
  	}

  	isicom_config_port(tty);

  	spin_unlock_irqrestore(&card->card_lock, flags);

  
  	return 0;
  }

  static int isicom_carrier_raised(struct tty_port *port)
  {
  	struct isi_port *ip = container_of(port, struct isi_port, port);
  	return (ip->status & ISI_DCD)?1 : 0;
  }

  static struct tty_port *isicom_find_port(struct tty_struct *tty)

  {

  	struct isi_port *port;
  	struct isi_board *card;

  	unsigned int board;

  	int line = tty->index;

  	board = BOARD(line);
  	card = &isi_card[board];

  	if (!(card->status & FIRMWARE_LOADED))

  		return NULL;

  	/*  open on a port greater than the port count for the card !!! */
  	if (line > ((board * 16) + card->port_count - 1))

  		return NULL;

  	port = &isi_ports[line];

  	if (isicom_paranoia_check(port, tty->name, "isicom_open"))

  		return NULL;
  
  	return &port->port;
  }

  static int isicom_open(struct tty_struct *tty, struct file *filp)
  {
  	struct isi_port *port;

  	struct tty_port *tport;

  	tport = isicom_find_port(tty);
  	if (tport == NULL)
  		return -ENODEV;
  	port = container_of(tport, struct isi_port, port);

  	tty->driver_data = port;

  	return tty_port_open(tport, tty, filp);

  }

  /* close et all */

  /* card->lock HAS to be held */

  static void isicom_shutdown_port(struct isi_port *port)

  {

  	struct isi_board *card = port->card;

  	if (--card->count < 0) {

  		pr_debug("%s: bad board(0x%lx) count %d.
  ",
  			 __func__, card->base, card->count);

  		card->count = 0;

  	}

  	/* last port was closed, shutdown that board too */

  	if (!card->count)
  		card->status &= BOARD_ACTIVE;

  }

  static void isicom_flush_buffer(struct tty_struct *tty)
  {
  	struct isi_port *port = tty->driver_data;
  	struct isi_board *card = port->card;
  	unsigned long flags;
  
  	if (isicom_paranoia_check(port, tty->name, "isicom_flush_buffer"))
  		return;
  
  	spin_lock_irqsave(&card->card_lock, flags);
  	port->xmit_cnt = port->xmit_head = port->xmit_tail = 0;
  	spin_unlock_irqrestore(&card->card_lock, flags);
  
  	tty_wakeup(tty);
  }

  static void isicom_shutdown(struct tty_port *port)

  {

  	struct isi_port *ip = container_of(port, struct isi_port, port);
  	struct isi_board *card = ip->card;

  	unsigned long flags;

  	/* indicate to the card that no more data can be received

  	   on this port */
  	spin_lock_irqsave(&card->card_lock, flags);

  	card->port_status &= ~(1 << ip->channel);
  	outw(card->port_status, card->base + 0x02);

  	isicom_shutdown_port(ip);

  	spin_unlock_irqrestore(&card->card_lock, flags);

  	tty_port_free_xmit_buf(port);

  }

  static void isicom_close(struct tty_struct *tty, struct file *filp)
  {
  	struct isi_port *ip = tty->driver_data;

  	struct tty_port *port;
  
  	if (ip == NULL)
  		return;
  
  	port = &ip->port;

  	if (isicom_paranoia_check(ip, tty->name, "isicom_close"))
  		return;

  	tty_port_close(port, tty, filp);

  }
  
  /* write et all */

  static int isicom_write(struct tty_struct *tty,	const unsigned char *buf,
  	int count)

  {

  	struct isi_port *port = tty->driver_data;

  	struct isi_board *card = port->card;

  	unsigned long flags;
  	int cnt, total = 0;
  
  	if (isicom_paranoia_check(port, tty->name, "isicom_write"))
  		return 0;

  	spin_lock_irqsave(&card->card_lock, flags);

  	while (1) {

  		cnt = min_t(int, count, min(SERIAL_XMIT_SIZE - port->xmit_cnt
  				- 1, SERIAL_XMIT_SIZE - port->xmit_head));

  		if (cnt <= 0)

  			break;

  		memcpy(port->port.xmit_buf + port->xmit_head, buf, cnt);

  		port->xmit_head = (port->xmit_head + cnt) & (SERIAL_XMIT_SIZE
  			- 1);

  		port->xmit_cnt += cnt;
  		buf += cnt;
  		count -= cnt;
  		total += cnt;

  	}

  	if (port->xmit_cnt && !tty->stopped && !tty->hw_stopped)
  		port->status |= ISI_TXOK;
  	spin_unlock_irqrestore(&card->card_lock, flags);

  	return total;

  }
  
  /* put_char et all */

  static int isicom_put_char(struct tty_struct *tty, unsigned char ch)

  {

  	struct isi_port *port = tty->driver_data;

  	struct isi_board *card = port->card;

  	unsigned long flags;

  	if (isicom_paranoia_check(port, tty->name, "isicom_put_char"))

  		return 0;

  	spin_lock_irqsave(&card->card_lock, flags);

  	if (port->xmit_cnt >= SERIAL_XMIT_SIZE - 1) {
  		spin_unlock_irqrestore(&card->card_lock, flags);
  		return 0;
  	}

  	port->port.xmit_buf[port->xmit_head++] = ch;

  	port->xmit_head &= (SERIAL_XMIT_SIZE - 1);
  	port->xmit_cnt++;
  	spin_unlock_irqrestore(&card->card_lock, flags);

  	return 1;

  }
  
  /* flush_chars et all */

  static void isicom_flush_chars(struct tty_struct *tty)

  {

  	struct isi_port *port = tty->driver_data;

  	if (isicom_paranoia_check(port, tty->name, "isicom_flush_chars"))
  		return;

  	if (port->xmit_cnt <= 0 || tty->stopped || tty->hw_stopped ||

  			!port->port.xmit_buf)

  		return;

  	/* this tells the transmitter to consider this port for
  	   data output to the card ... that's the best we can do. */

  	port->status |= ISI_TXOK;

  }
  
  /* write_room et all */

  static int isicom_write_room(struct tty_struct *tty)

  {

  	struct isi_port *port = tty->driver_data;

  	int free;
  
  	if (isicom_paranoia_check(port, tty->name, "isicom_write_room"))
  		return 0;

  	free = SERIAL_XMIT_SIZE - port->xmit_cnt - 1;
  	if (free < 0)
  		free = 0;
  	return free;
  }
  
  /* chars_in_buffer et all */

  static int isicom_chars_in_buffer(struct tty_struct *tty)

  {

  	struct isi_port *port = tty->driver_data;

  	if (isicom_paranoia_check(port, tty->name, "isicom_chars_in_buffer"))
  		return 0;
  	return port->xmit_cnt;
  }
  
  /* ioctl et all */

  static int isicom_send_break(struct tty_struct *tty, int length)

  {

  	struct isi_port *port = tty->driver_data;

  	struct isi_board *card = port->card;

  	unsigned long base = card->base;

  	if (length == -1)
  		return -EOPNOTSUPP;

  	if (!lock_card(card))

  		return -EINVAL;

  	outw(0x8000 | ((port->channel) << (card->shift_count)) | 0x3, base);
  	outw((length & 0xff) << 8 | 0x00, base);

  	outw((length & 0xff00u), base);

  	InterruptTheCard(base);
  
  	unlock_card(card);

  	return 0;

  }

  static int isicom_tiocmget(struct tty_struct *tty)

  {

  	struct isi_port *port = tty->driver_data;

  	/* just send the port status */

  	u16 status = port->status;

  
  	if (isicom_paranoia_check(port, tty->name, "isicom_ioctl"))
  		return -ENODEV;

  	return  ((status & ISI_RTS) ? TIOCM_RTS : 0) |
  		((status & ISI_DTR) ? TIOCM_DTR : 0) |
  		((status & ISI_DCD) ? TIOCM_CAR : 0) |
  		((status & ISI_DSR) ? TIOCM_DSR : 0) |
  		((status & ISI_CTS) ? TIOCM_CTS : 0) |
  		((status & ISI_RI ) ? TIOCM_RI  : 0);
  }

  static int isicom_tiocmset(struct tty_struct *tty,
  					unsigned int set, unsigned int clear)

  {

  	struct isi_port *port = tty->driver_data;

  	unsigned long flags;

  	if (isicom_paranoia_check(port, tty->name, "isicom_ioctl"))
  		return -ENODEV;

  	spin_lock_irqsave(&port->card->card_lock, flags);

  	if (set & TIOCM_RTS)
  		raise_rts(port);
  	if (set & TIOCM_DTR)
  		raise_dtr(port);
  
  	if (clear & TIOCM_RTS)
  		drop_rts(port);
  	if (clear & TIOCM_DTR)
  		drop_dtr(port);

  	spin_unlock_irqrestore(&port->card->card_lock, flags);

  
  	return 0;

  }

  static int isicom_set_serial_info(struct tty_struct *tty,

  					struct serial_struct *ss)

  {

  	struct isi_port *port = tty->driver_data;

  	int reconfig_port;

  	if (isicom_paranoia_check(port, tty->name, "isicom_ioctl"))
  		return -ENODEV;

  	mutex_lock(&port->port.mutex);

  	reconfig_port = ((port->port.flags & ASYNC_SPD_MASK) !=

  		(ss->flags & ASYNC_SPD_MASK));

  	if (!capable(CAP_SYS_ADMIN)) {

  		if ((ss->close_delay != port->port.close_delay) ||
  				(ss->closing_wait != port->port.closing_wait) ||
  				((ss->flags & ~ASYNC_USR_MASK) !=

  				(port->port.flags & ~ASYNC_USR_MASK))) {

  			mutex_unlock(&port->port.mutex);

  			return -EPERM;

  		}

  		port->port.flags = ((port->port.flags & ~ASYNC_USR_MASK) |

  				(ss->flags & ASYNC_USR_MASK));

  	} else {

  		port->port.close_delay = ss->close_delay;
  		port->port.closing_wait = ss->closing_wait;

  		port->port.flags = ((port->port.flags & ~ASYNC_FLAGS) |

  				(ss->flags & ASYNC_FLAGS));

  	}
  	if (reconfig_port) {

  		unsigned long flags;
  		spin_lock_irqsave(&port->card->card_lock, flags);

  		isicom_config_port(tty);

  		spin_unlock_irqrestore(&port->card->card_lock, flags);

  	}

  	mutex_unlock(&port->port.mutex);

  	return 0;
  }

  static int isicom_get_serial_info(struct tty_struct *tty,
  	struct serial_struct *ss)

  {

  	struct isi_port *port = tty->driver_data;

  
  	if (isicom_paranoia_check(port, tty->name, "isicom_ioctl"))
  		return -ENODEV;

  	mutex_lock(&port->port.mutex);
  /*	ss->type = ? */
  	ss->line = port - isi_ports;
  	ss->port = port->card->base;
  	ss->irq = port->card->irq;
  	ss->flags = port->port.flags;
  /*	ss->baud_base = ? */
  	ss->close_delay = port->port.close_delay;
  	ss->closing_wait = port->port.closing_wait;
  	mutex_unlock(&port->port.mutex);

  	return 0;
  }
  
  /* set_termios et all */

  static void isicom_set_termios(struct tty_struct *tty,

  	struct ktermios *old_termios)

  {

  	struct isi_port *port = tty->driver_data;

  	unsigned long flags;

  	if (isicom_paranoia_check(port, tty->name, "isicom_set_termios"))
  		return;

  	if (tty->termios.c_cflag == old_termios->c_cflag &&
  			tty->termios.c_iflag == old_termios->c_iflag)

  		return;

  	spin_lock_irqsave(&port->card->card_lock, flags);

  	isicom_config_port(tty);

  	spin_unlock_irqrestore(&port->card->card_lock, flags);

  	if ((old_termios->c_cflag & CRTSCTS) && !C_CRTSCTS(tty)) {

  		tty->hw_stopped = 0;

  		isicom_start(tty);
  	}

  }
  
  /* throttle et all */

  static void isicom_throttle(struct tty_struct *tty)

  {

  	struct isi_port *port = tty->driver_data;

  	struct isi_board *card = port->card;

  	if (isicom_paranoia_check(port, tty->name, "isicom_throttle"))
  		return;

  	/* tell the card that this port cannot handle any more data for now */
  	card->port_status &= ~(1 << port->channel);
  	outw(card->port_status, card->base + 0x02);
  }
  
  /* unthrottle et all */