/*
   *          mxser.c  -- MOXA Smartio/Industio family multiport serial driver.
   *

   *      Copyright (C) 1999-2006  Moxa Technologies (support@moxa.com).
   *	Copyright (C) 2006-2008  Jiri Slaby <jirislaby@gmail.com>

   *

   *      This code is loosely based on the 1.8 moxa driver which is based on
   *	Linux serial driver, written by Linus Torvalds, Theodore T'so and
   *	others.

   *
   *      This program is free software; you can redistribute it and/or modify
   *      it under the terms of the GNU General Public License as published by
   *      the Free Software Foundation; either version 2 of the License, or

   *      (at your option) any later version.

   *

   *	Fed through a cleanup, indent and remove of non 2.6 code by Alan Cox

   *	<alan@lxorguk.ukuu.org.uk>. The original 1.8 code is available on
   *	www.moxa.com.

   *	- Fixed x86_64 cleanness

   */

  #include <linux/module.h>

  #include <linux/errno.h>
  #include <linux/signal.h>
  #include <linux/sched.h>
  #include <linux/timer.h>
  #include <linux/interrupt.h>
  #include <linux/tty.h>
  #include <linux/tty_flip.h>
  #include <linux/serial.h>
  #include <linux/serial_reg.h>
  #include <linux/major.h>
  #include <linux/string.h>
  #include <linux/fcntl.h>
  #include <linux/ptrace.h>

  #include <linux/ioport.h>
  #include <linux/mm.h>

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

  #include <linux/bitops.h>

  #include <linux/slab.h>

  #include <linux/ratelimit.h>

  
  #include <asm/system.h>
  #include <asm/io.h>
  #include <asm/irq.h>

  #include <asm/uaccess.h>
  
  #include "mxser.h"

  #define	MXSER_VERSION	"2.0.5"		/* 1.14 */

  #define	MXSERMAJOR	 174

  #define MXSER_BOARDS		4	/* Max. boards */

  #define MXSER_PORTS_PER_BOARD	8	/* Max. ports per board */

  #define MXSER_PORTS		(MXSER_BOARDS * MXSER_PORTS_PER_BOARD)
  #define MXSER_ISR_PASS_LIMIT	100

  /*CheckIsMoxaMust return value*/
  #define MOXA_OTHER_UART		0x00
  #define MOXA_MUST_MU150_HWID	0x01
  #define MOXA_MUST_MU860_HWID	0x02

  #define WAKEUP_CHARS		256
  
  #define UART_MCR_AFE		0x20
  #define UART_LSR_SPECIAL	0x1E

  #define PCI_DEVICE_ID_POS104UL	0x1044

  #define PCI_DEVICE_ID_CB108	0x1080

  #define PCI_DEVICE_ID_CP102UF	0x1023

  #define PCI_DEVICE_ID_CP112UL	0x1120

  #define PCI_DEVICE_ID_CB114	0x1142

  #define PCI_DEVICE_ID_CP114UL	0x1143

  #define PCI_DEVICE_ID_CB134I	0x1341
  #define PCI_DEVICE_ID_CP138U	0x1380

  
  #define C168_ASIC_ID    1
  #define C104_ASIC_ID    2
  #define C102_ASIC_ID	0xB
  #define CI132_ASIC_ID	4
  #define CI134_ASIC_ID	3
  #define CI104J_ASIC_ID  5

  #define MXSER_HIGHBAUD	1
  #define MXSER_HAS2	2

  /* This is only for PCI */

  static const struct {

  	int type;
  	int tx_fifo;
  	int rx_fifo;
  	int xmit_fifo_size;
  	int rx_high_water;
  	int rx_trigger;
  	int rx_low_water;
  	long max_baud;

  } Gpci_uart_info[] = {

  	{MOXA_OTHER_UART, 16, 16, 16, 14, 14, 1, 921600L},
  	{MOXA_MUST_MU150_HWID, 64, 64, 64, 48, 48, 16, 230400L},
  	{MOXA_MUST_MU860_HWID, 128, 128, 128, 96, 96, 32, 921600L}
  };

  #define UART_INFO_NUM	ARRAY_SIZE(Gpci_uart_info)

  struct mxser_cardinfo {
  	char *name;
  	unsigned int nports;
  	unsigned int flags;
  };

  static const struct mxser_cardinfo mxser_cards[] = {
  /* 0*/	{ "C168 series",	8, },
  	{ "C104 series",	4, },
  	{ "CI-104J series",	4, },
  	{ "C168H/PCI series",	8, },
  	{ "C104H/PCI series",	4, },
  /* 5*/	{ "C102 series",	4, MXSER_HAS2 },	/* C102-ISA */
  	{ "CI-132 series",	4, MXSER_HAS2 },
  	{ "CI-134 series",	4, },
  	{ "CP-132 series",	2, },
  	{ "CP-114 series",	4, },
  /*10*/	{ "CT-114 series",	4, },
  	{ "CP-102 series",	2, MXSER_HIGHBAUD },
  	{ "CP-104U series",	4, },
  	{ "CP-168U series",	8, },
  	{ "CP-132U series",	2, },
  /*15*/	{ "CP-134U series",	4, },
  	{ "CP-104JU series",	4, },
  	{ "Moxa UC7000 Serial",	8, },		/* RC7000 */
  	{ "CP-118U series",	8, },
  	{ "CP-102UL series",	2, },
  /*20*/	{ "CP-102U series",	2, },
  	{ "CP-118EL series",	8, },
  	{ "CP-168EL series",	8, },
  	{ "CP-104EL series",	4, },
  	{ "CB-108 series",	8, },
  /*25*/	{ "CB-114 series",	4, },
  	{ "CB-134I series",	4, },
  	{ "CP-138U series",	8, },

  	{ "POS-104UL series",	4, },

  	{ "CP-114UL series",	4, },

  /*30*/	{ "CP-102UF series",	2, },
  	{ "CP-112UL series",	2, },

  };

  /* driver_data correspond to the lines in the structure above
     see also ISA probe function before you change something */

  static struct pci_device_id mxser_pcibrds[] = {

  	{ PCI_VDEVICE(MOXA, PCI_DEVICE_ID_MOXA_C168),	.driver_data = 3 },
  	{ PCI_VDEVICE(MOXA, PCI_DEVICE_ID_MOXA_C104),	.driver_data = 4 },
  	{ PCI_VDEVICE(MOXA, PCI_DEVICE_ID_MOXA_CP132),	.driver_data = 8 },
  	{ PCI_VDEVICE(MOXA, PCI_DEVICE_ID_MOXA_CP114),	.driver_data = 9 },
  	{ PCI_VDEVICE(MOXA, PCI_DEVICE_ID_MOXA_CT114),	.driver_data = 10 },
  	{ PCI_VDEVICE(MOXA, PCI_DEVICE_ID_MOXA_CP102),	.driver_data = 11 },
  	{ PCI_VDEVICE(MOXA, PCI_DEVICE_ID_MOXA_CP104U),	.driver_data = 12 },
  	{ PCI_VDEVICE(MOXA, PCI_DEVICE_ID_MOXA_CP168U),	.driver_data = 13 },
  	{ PCI_VDEVICE(MOXA, PCI_DEVICE_ID_MOXA_CP132U),	.driver_data = 14 },
  	{ PCI_VDEVICE(MOXA, PCI_DEVICE_ID_MOXA_CP134U),	.driver_data = 15 },
  	{ PCI_VDEVICE(MOXA, PCI_DEVICE_ID_MOXA_CP104JU),.driver_data = 16 },
  	{ PCI_VDEVICE(MOXA, PCI_DEVICE_ID_MOXA_RC7000),	.driver_data = 17 },
  	{ PCI_VDEVICE(MOXA, PCI_DEVICE_ID_MOXA_CP118U),	.driver_data = 18 },
  	{ PCI_VDEVICE(MOXA, PCI_DEVICE_ID_MOXA_CP102UL),.driver_data = 19 },
  	{ PCI_VDEVICE(MOXA, PCI_DEVICE_ID_MOXA_CP102U),	.driver_data = 20 },
  	{ PCI_VDEVICE(MOXA, PCI_DEVICE_ID_MOXA_CP118EL),.driver_data = 21 },
  	{ PCI_VDEVICE(MOXA, PCI_DEVICE_ID_MOXA_CP168EL),.driver_data = 22 },
  	{ PCI_VDEVICE(MOXA, PCI_DEVICE_ID_MOXA_CP104EL),.driver_data = 23 },
  	{ PCI_VDEVICE(MOXA, PCI_DEVICE_ID_CB108),	.driver_data = 24 },
  	{ PCI_VDEVICE(MOXA, PCI_DEVICE_ID_CB114),	.driver_data = 25 },
  	{ PCI_VDEVICE(MOXA, PCI_DEVICE_ID_CB134I),	.driver_data = 26 },
  	{ PCI_VDEVICE(MOXA, PCI_DEVICE_ID_CP138U),	.driver_data = 27 },
  	{ PCI_VDEVICE(MOXA, PCI_DEVICE_ID_POS104UL),	.driver_data = 28 },

  	{ PCI_VDEVICE(MOXA, PCI_DEVICE_ID_CP114UL),	.driver_data = 29 },

  	{ PCI_VDEVICE(MOXA, PCI_DEVICE_ID_CP102UF),	.driver_data = 30 },

  	{ PCI_VDEVICE(MOXA, PCI_DEVICE_ID_CP112UL),	.driver_data = 31 },

  	{ }

  };

  MODULE_DEVICE_TABLE(pci, mxser_pcibrds);

  static unsigned long ioaddr[MXSER_BOARDS];

  static int ttymajor = MXSERMAJOR;

  
  /* Variables for insmod */
  
  MODULE_AUTHOR("Casper Yang");
  MODULE_DESCRIPTION("MOXA Smartio/Industio Family Multiport Board Device Driver");

  module_param_array(ioaddr, ulong, NULL, 0);
  MODULE_PARM_DESC(ioaddr, "ISA io addresses to look for a moxa board");

  module_param(ttymajor, int, 0);

  MODULE_LICENSE("GPL");
  
  struct mxser_log {
  	int tick;
  	unsigned long rxcnt[MXSER_PORTS];
  	unsigned long txcnt[MXSER_PORTS];
  };

  struct mxser_mon {
  	unsigned long rxcnt;
  	unsigned long txcnt;
  	unsigned long up_rxcnt;
  	unsigned long up_txcnt;
  	int modem_status;
  	unsigned char hold_reason;
  };
  
  struct mxser_mon_ext {
  	unsigned long rx_cnt[32];
  	unsigned long tx_cnt[32];
  	unsigned long up_rxcnt[32];
  	unsigned long up_txcnt[32];
  	int modem_status[32];
  
  	long baudrate[32];
  	int databits[32];
  	int stopbits[32];
  	int parity[32];
  	int flowctrl[32];
  	int fifo[32];
  	int iftype[32];
  };

  struct mxser_board;
  
  struct mxser_port {

  	struct tty_port port;

  	struct mxser_board *board;

  
  	unsigned long ioaddr;
  	unsigned long opmode_ioaddr;
  	int max_baud;

  	int rx_high_water;
  	int rx_trigger;		/* Rx fifo trigger level */
  	int rx_low_water;
  	int baud_base;		/* max. speed */

  	int type;		/* UART type */

  	int x_char;		/* xon/xoff character */

  	int IER;		/* Interrupt Enable Register */
  	int MCR;		/* Modem control register */

  
  	unsigned char stop_rx;
  	unsigned char ldisc_stop_rx;
  
  	int custom_divisor;

  	unsigned char err_shadow;

  	struct async_icount icount; /* kernel counters for 4 input interrupts */
  	int timeout;
  
  	int read_status_mask;
  	int ignore_status_mask;
  	int xmit_fifo_size;

  	int xmit_head;
  	int xmit_tail;
  	int xmit_cnt;

  	struct ktermios normal_termios;

  	struct mxser_mon mon_data;

  	spinlock_t slock;

  };
  
  struct mxser_board {
  	unsigned int idx;
  	int irq;
  	const struct mxser_cardinfo *info;
  	unsigned long vector;
  	unsigned long vector_mask;
  
  	int chip_flag;
  	int uart_type;
  
  	struct mxser_port ports[MXSER_PORTS_PER_BOARD];

  };

  struct mxser_mstatus {
  	tcflag_t cflag;
  	int cts;
  	int dsr;
  	int ri;
  	int dcd;
  };

  static struct mxser_board mxser_boards[MXSER_BOARDS];

  static struct tty_driver *mxvar_sdriver;

  static struct mxser_log mxvar_log;

  static int mxser_set_baud_method[MXSER_PORTS + 1];

  static void mxser_enable_must_enchance_mode(unsigned long baseio)
  {
  	u8 oldlcr;
  	u8 efr;
  
  	oldlcr = inb(baseio + UART_LCR);
  	outb(MOXA_MUST_ENTER_ENCHANCE, baseio + UART_LCR);
  
  	efr = inb(baseio + MOXA_MUST_EFR_REGISTER);
  	efr |= MOXA_MUST_EFR_EFRB_ENABLE;
  
  	outb(efr, baseio + MOXA_MUST_EFR_REGISTER);
  	outb(oldlcr, baseio + UART_LCR);
  }

  #ifdef	CONFIG_PCI

  static void mxser_disable_must_enchance_mode(unsigned long baseio)
  {
  	u8 oldlcr;
  	u8 efr;
  
  	oldlcr = inb(baseio + UART_LCR);
  	outb(MOXA_MUST_ENTER_ENCHANCE, baseio + UART_LCR);
  
  	efr = inb(baseio + MOXA_MUST_EFR_REGISTER);
  	efr &= ~MOXA_MUST_EFR_EFRB_ENABLE;
  
  	outb(efr, baseio + MOXA_MUST_EFR_REGISTER);
  	outb(oldlcr, baseio + UART_LCR);
  }

  #endif

  
  static void mxser_set_must_xon1_value(unsigned long baseio, u8 value)
  {
  	u8 oldlcr;
  	u8 efr;
  
  	oldlcr = inb(baseio + UART_LCR);
  	outb(MOXA_MUST_ENTER_ENCHANCE, baseio + UART_LCR);
  
  	efr = inb(baseio + MOXA_MUST_EFR_REGISTER);
  	efr &= ~MOXA_MUST_EFR_BANK_MASK;
  	efr |= MOXA_MUST_EFR_BANK0;
  
  	outb(efr, baseio + MOXA_MUST_EFR_REGISTER);
  	outb(value, baseio + MOXA_MUST_XON1_REGISTER);
  	outb(oldlcr, baseio + UART_LCR);
  }
  
  static void mxser_set_must_xoff1_value(unsigned long baseio, u8 value)
  {
  	u8 oldlcr;
  	u8 efr;
  
  	oldlcr = inb(baseio + UART_LCR);
  	outb(MOXA_MUST_ENTER_ENCHANCE, baseio + UART_LCR);
  
  	efr = inb(baseio + MOXA_MUST_EFR_REGISTER);
  	efr &= ~MOXA_MUST_EFR_BANK_MASK;
  	efr |= MOXA_MUST_EFR_BANK0;
  
  	outb(efr, baseio + MOXA_MUST_EFR_REGISTER);
  	outb(value, baseio + MOXA_MUST_XOFF1_REGISTER);
  	outb(oldlcr, baseio + UART_LCR);
  }
  
  static void mxser_set_must_fifo_value(struct mxser_port *info)
  {
  	u8 oldlcr;
  	u8 efr;
  
  	oldlcr = inb(info->ioaddr + UART_LCR);
  	outb(MOXA_MUST_ENTER_ENCHANCE, info->ioaddr + UART_LCR);
  
  	efr = inb(info->ioaddr + MOXA_MUST_EFR_REGISTER);
  	efr &= ~MOXA_MUST_EFR_BANK_MASK;
  	efr |= MOXA_MUST_EFR_BANK1;
  
  	outb(efr, info->ioaddr + MOXA_MUST_EFR_REGISTER);
  	outb((u8)info->rx_high_water, info->ioaddr + MOXA_MUST_RBRTH_REGISTER);
  	outb((u8)info->rx_trigger, info->ioaddr + MOXA_MUST_RBRTI_REGISTER);
  	outb((u8)info->rx_low_water, info->ioaddr + MOXA_MUST_RBRTL_REGISTER);
  	outb(oldlcr, info->ioaddr + UART_LCR);
  }
  
  static void mxser_set_must_enum_value(unsigned long baseio, u8 value)
  {
  	u8 oldlcr;
  	u8 efr;
  
  	oldlcr = inb(baseio + UART_LCR);
  	outb(MOXA_MUST_ENTER_ENCHANCE, baseio + UART_LCR);
  
  	efr = inb(baseio + MOXA_MUST_EFR_REGISTER);
  	efr &= ~MOXA_MUST_EFR_BANK_MASK;
  	efr |= MOXA_MUST_EFR_BANK2;
  
  	outb(efr, baseio + MOXA_MUST_EFR_REGISTER);
  	outb(value, baseio + MOXA_MUST_ENUM_REGISTER);
  	outb(oldlcr, baseio + UART_LCR);
  }

  #ifdef CONFIG_PCI

  static void mxser_get_must_hardware_id(unsigned long baseio, u8 *pId)
  {
  	u8 oldlcr;
  	u8 efr;
  
  	oldlcr = inb(baseio + UART_LCR);
  	outb(MOXA_MUST_ENTER_ENCHANCE, baseio + UART_LCR);
  
  	efr = inb(baseio + MOXA_MUST_EFR_REGISTER);
  	efr &= ~MOXA_MUST_EFR_BANK_MASK;
  	efr |= MOXA_MUST_EFR_BANK2;
  
  	outb(efr, baseio + MOXA_MUST_EFR_REGISTER);
  	*pId = inb(baseio + MOXA_MUST_HWID_REGISTER);
  	outb(oldlcr, baseio + UART_LCR);
  }

  #endif

  
  static void SET_MOXA_MUST_NO_SOFTWARE_FLOW_CONTROL(unsigned long baseio)
  {
  	u8 oldlcr;
  	u8 efr;
  
  	oldlcr = inb(baseio + UART_LCR);
  	outb(MOXA_MUST_ENTER_ENCHANCE, baseio + UART_LCR);
  
  	efr = inb(baseio + MOXA_MUST_EFR_REGISTER);
  	efr &= ~MOXA_MUST_EFR_SF_MASK;
  
  	outb(efr, baseio + MOXA_MUST_EFR_REGISTER);
  	outb(oldlcr, baseio + UART_LCR);
  }
  
  static void mxser_enable_must_tx_software_flow_control(unsigned long baseio)
  {
  	u8 oldlcr;
  	u8 efr;
  
  	oldlcr = inb(baseio + UART_LCR);
  	outb(MOXA_MUST_ENTER_ENCHANCE, baseio + UART_LCR);
  
  	efr = inb(baseio + MOXA_MUST_EFR_REGISTER);
  	efr &= ~MOXA_MUST_EFR_SF_TX_MASK;
  	efr |= MOXA_MUST_EFR_SF_TX1;
  
  	outb(efr, baseio + MOXA_MUST_EFR_REGISTER);
  	outb(oldlcr, baseio + UART_LCR);
  }
  
  static void mxser_disable_must_tx_software_flow_control(unsigned long baseio)
  {
  	u8 oldlcr;
  	u8 efr;
  
  	oldlcr = inb(baseio + UART_LCR);
  	outb(MOXA_MUST_ENTER_ENCHANCE, baseio + UART_LCR);
  
  	efr = inb(baseio + MOXA_MUST_EFR_REGISTER);
  	efr &= ~MOXA_MUST_EFR_SF_TX_MASK;
  
  	outb(efr, baseio + MOXA_MUST_EFR_REGISTER);
  	outb(oldlcr, baseio + UART_LCR);
  }
  
  static void mxser_enable_must_rx_software_flow_control(unsigned long baseio)
  {
  	u8 oldlcr;
  	u8 efr;
  
  	oldlcr = inb(baseio + UART_LCR);
  	outb(MOXA_MUST_ENTER_ENCHANCE, baseio + UART_LCR);
  
  	efr = inb(baseio + MOXA_MUST_EFR_REGISTER);
  	efr &= ~MOXA_MUST_EFR_SF_RX_MASK;
  	efr |= MOXA_MUST_EFR_SF_RX1;
  
  	outb(efr, baseio + MOXA_MUST_EFR_REGISTER);
  	outb(oldlcr, baseio + UART_LCR);
  }
  
  static void mxser_disable_must_rx_software_flow_control(unsigned long baseio)
  {
  	u8 oldlcr;
  	u8 efr;
  
  	oldlcr = inb(baseio + UART_LCR);
  	outb(MOXA_MUST_ENTER_ENCHANCE, baseio + UART_LCR);
  
  	efr = inb(baseio + MOXA_MUST_EFR_REGISTER);
  	efr &= ~MOXA_MUST_EFR_SF_RX_MASK;
  
  	outb(efr, baseio + MOXA_MUST_EFR_REGISTER);
  	outb(oldlcr, baseio + UART_LCR);
  }

  #ifdef CONFIG_PCI

  static int __devinit CheckIsMoxaMust(unsigned long io)

  {
  	u8 oldmcr, hwid;
  	int i;
  
  	outb(0, io + UART_LCR);

  	mxser_disable_must_enchance_mode(io);

  	oldmcr = inb(io + UART_MCR);
  	outb(0, io + UART_MCR);

  	mxser_set_must_xon1_value(io, 0x11);

  	if ((hwid = inb(io + UART_MCR)) != 0) {
  		outb(oldmcr, io + UART_MCR);

  		return MOXA_OTHER_UART;

  	}

  	mxser_get_must_hardware_id(io, &hwid);

  	for (i = 1; i < UART_INFO_NUM; i++) { /* 0 = OTHER_UART */
  		if (hwid == Gpci_uart_info[i].type)

  			return (int)hwid;

  	}
  	return MOXA_OTHER_UART;
  }

  #endif

  static void process_txrx_fifo(struct mxser_port *info)

  {
  	int i;
  
  	if ((info->type == PORT_16450) || (info->type == PORT_8250)) {
  		info->rx_trigger = 1;
  		info->rx_high_water = 1;
  		info->rx_low_water = 1;
  		info->xmit_fifo_size = 1;

  	} else
  		for (i = 0; i < UART_INFO_NUM; i++)
  			if (info->board->chip_flag == Gpci_uart_info[i].type) {

  				info->rx_trigger = Gpci_uart_info[i].rx_trigger;
  				info->rx_low_water = Gpci_uart_info[i].rx_low_water;
  				info->rx_high_water = Gpci_uart_info[i].rx_high_water;
  				info->xmit_fifo_size = Gpci_uart_info[i].xmit_fifo_size;
  				break;
  			}

  }

  static unsigned char mxser_get_msr(int baseaddr, int mode, int port)

  {

  	static unsigned char mxser_msr[MXSER_PORTS + 1];

  	unsigned char status = 0;

  	status = inb(baseaddr + UART_MSR);

  	mxser_msr[port] &= 0x0F;
  	mxser_msr[port] |= status;
  	status = mxser_msr[port];
  	if (mode)
  		mxser_msr[port] = 0;

  	return status;
  }

  static int mxser_carrier_raised(struct tty_port *port)
  {
  	struct mxser_port *mp = container_of(port, struct mxser_port, port);
  	return (inb(mp->ioaddr + UART_MSR) & UART_MSR_DCD)?1:0;
  }

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

  {
  	struct mxser_port *mp = container_of(port, struct mxser_port, port);
  	unsigned long flags;
  
  	spin_lock_irqsave(&mp->slock, flags);

  	if (on)
  		outb(inb(mp->ioaddr + UART_MCR) |
  			UART_MCR_DTR | UART_MCR_RTS, mp->ioaddr + UART_MCR);
  	else
  		outb(inb(mp->ioaddr + UART_MCR)&~(UART_MCR_DTR | UART_MCR_RTS),
  			mp->ioaddr + UART_MCR);

  	spin_unlock_irqrestore(&mp->slock, flags);
  }

  static int mxser_set_baud(struct tty_struct *tty, long newspd)

  {

  	struct mxser_port *info = tty->driver_data;

  	int quot = 0, baud;
  	unsigned char cval;

  	if (!info->ioaddr)

  		return -1;

  	if (newspd > info->max_baud)
  		return -1;

  	if (newspd == 134) {
  		quot = 2 * info->baud_base / 269;

  		tty_encode_baud_rate(tty, 134, 134);

  	} else if (newspd) {
  		quot = info->baud_base / newspd;
  		if (quot == 0)
  			quot = 1;
  		baud = info->baud_base/quot;

  		tty_encode_baud_rate(tty, baud, baud);

  	} else {
  		quot = 0;
  	}

  	info->timeout = ((info->xmit_fifo_size * HZ * 10 * quot) / info->baud_base);
  	info->timeout += HZ / 50;	/* Add .02 seconds of slop */

  	if (quot) {
  		info->MCR |= UART_MCR_DTR;
  		outb(info->MCR, info->ioaddr + UART_MCR);
  	} else {
  		info->MCR &= ~UART_MCR_DTR;
  		outb(info->MCR, info->ioaddr + UART_MCR);
  		return 0;
  	}

  	cval = inb(info->ioaddr + UART_LCR);

  	outb(cval | UART_LCR_DLAB, info->ioaddr + UART_LCR);	/* set DLAB */

  	outb(quot & 0xff, info->ioaddr + UART_DLL);	/* LS of divisor */
  	outb(quot >> 8, info->ioaddr + UART_DLM);	/* MS of divisor */
  	outb(cval, info->ioaddr + UART_LCR);	/* reset DLAB */

  #ifdef BOTHER

  	if (C_BAUD(tty) == BOTHER) {

  		quot = info->baud_base % newspd;
  		quot *= 8;
  		if (quot % newspd > newspd / 2) {
  			quot /= newspd;
  			quot++;
  		} else
  			quot /= newspd;

  		mxser_set_must_enum_value(info->ioaddr, quot);

  	} else
  #endif

  		mxser_set_must_enum_value(info->ioaddr, 0);

  	return 0;

  }

  /*
   * This routine is called to set the UART divisor registers to match
   * the specified baud rate for a serial port.
   */

  static int mxser_change_speed(struct tty_struct *tty,
  					struct ktermios *old_termios)

  {

  	struct mxser_port *info = tty->driver_data;

  	unsigned cflag, cval, fcr;
  	int ret = 0;
  	unsigned char status;

  	cflag = tty->termios->c_cflag;
  	if (!info->ioaddr)

  		return ret;

  	if (mxser_set_baud_method[tty->index] == 0)
  		mxser_set_baud(tty, tty_get_baud_rate(tty));

  	/* byte size and parity */
  	switch (cflag & CSIZE) {
  	case CS5:
  		cval = 0x00;
  		break;
  	case CS6:
  		cval = 0x01;
  		break;
  	case CS7:
  		cval = 0x02;
  		break;
  	case CS8:
  		cval = 0x03;
  		break;
  	default:
  		cval = 0x00;
  		break;		/* too keep GCC shut... */
  	}
  	if (cflag & CSTOPB)
  		cval |= 0x04;
  	if (cflag & PARENB)
  		cval |= UART_LCR_PARITY;
  	if (!(cflag & PARODD))
  		cval |= UART_LCR_EPAR;
  	if (cflag & CMSPAR)
  		cval |= UART_LCR_SPAR;

  	if ((info->type == PORT_8250) || (info->type == PORT_16450)) {
  		if (info->board->chip_flag) {
  			fcr = UART_FCR_ENABLE_FIFO;
  			fcr |= MOXA_MUST_FCR_GDA_MODE_ENABLE;

  			mxser_set_must_fifo_value(info);

  		} else
  			fcr = 0;
  	} else {
  		fcr = UART_FCR_ENABLE_FIFO;
  		if (info->board->chip_flag) {
  			fcr |= MOXA_MUST_FCR_GDA_MODE_ENABLE;

  			mxser_set_must_fifo_value(info);

  		} else {
  			switch (info->rx_trigger) {
  			case 1:
  				fcr |= UART_FCR_TRIGGER_1;
  				break;
  			case 4:
  				fcr |= UART_FCR_TRIGGER_4;
  				break;
  			case 8:
  				fcr |= UART_FCR_TRIGGER_8;
  				break;
  			default:
  				fcr |= UART_FCR_TRIGGER_14;
  				break;
  			}

  		}

  	}

  	/* CTS flow control flag and modem status interrupts */
  	info->IER &= ~UART_IER_MSI;
  	info->MCR &= ~UART_MCR_AFE;
  	if (cflag & CRTSCTS) {

  		info->port.flags |= ASYNC_CTS_FLOW;

  		info->IER |= UART_IER_MSI;
  		if ((info->type == PORT_16550A) || (info->board->chip_flag)) {
  			info->MCR |= UART_MCR_AFE;
  		} else {
  			status = inb(info->ioaddr + UART_MSR);

  			if (tty->hw_stopped) {

  				if (status & UART_MSR_CTS) {

  					tty->hw_stopped = 0;

  					if (info->type != PORT_16550A &&
  							!info->board->chip_flag) {
  						outb(info->IER & ~UART_IER_THRI,
  							info->ioaddr +
  							UART_IER);
  						info->IER |= UART_IER_THRI;
  						outb(info->IER, info->ioaddr +
  								UART_IER);
  					}

  					tty_wakeup(tty);

  				}
  			} else {
  				if (!(status & UART_MSR_CTS)) {

  					tty->hw_stopped = 1;

  					if ((info->type != PORT_16550A) &&
  							(!info->board->chip_flag)) {
  						info->IER &= ~UART_IER_THRI;
  						outb(info->IER, info->ioaddr +
  								UART_IER);
  					}
  				}
  			}

  		}

  	} else {

  		info->port.flags &= ~ASYNC_CTS_FLOW;

  	}
  	outb(info->MCR, info->ioaddr + UART_MCR);
  	if (cflag & CLOCAL) {

  		info->port.flags &= ~ASYNC_CHECK_CD;

  	} else {

  		info->port.flags |= ASYNC_CHECK_CD;

  		info->IER |= UART_IER_MSI;
  	}
  	outb(info->IER, info->ioaddr + UART_IER);
  
  	/*
  	 * Set up parity check flag
  	 */
  	info->read_status_mask = UART_LSR_OE | UART_LSR_THRE | UART_LSR_DR;

  	if (I_INPCK(tty))

  		info->read_status_mask |= UART_LSR_FE | UART_LSR_PE;

  	if (I_BRKINT(tty) || I_PARMRK(tty))

  		info->read_status_mask |= UART_LSR_BI;

  	info->ignore_status_mask = 0;

  	if (I_IGNBRK(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(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 (info->board->chip_flag) {

  		mxser_set_must_xon1_value(info->ioaddr, START_CHAR(tty));
  		mxser_set_must_xoff1_value(info->ioaddr, STOP_CHAR(tty));
  		if (I_IXON(tty)) {

  			mxser_enable_must_rx_software_flow_control(
  					info->ioaddr);

  		} else {

  			mxser_disable_must_rx_software_flow_control(
  					info->ioaddr);

  		}

  		if (I_IXOFF(tty)) {

  			mxser_enable_must_tx_software_flow_control(
  					info->ioaddr);

  		} else {

  			mxser_disable_must_tx_software_flow_control(
  					info->ioaddr);

  		}
  	}

  	outb(fcr, info->ioaddr + UART_FCR);	/* set fcr */
  	outb(cval, info->ioaddr + UART_LCR);

  	return ret;

  }

  static void mxser_check_modem_status(struct tty_struct *tty,
  				struct mxser_port *port, int status)

  {

  	/* update input line counters */
  	if (status & UART_MSR_TERI)
  		port->icount.rng++;
  	if (status & UART_MSR_DDSR)
  		port->icount.dsr++;
  	if (status & UART_MSR_DDCD)
  		port->icount.dcd++;
  	if (status & UART_MSR_DCTS)
  		port->icount.cts++;
  	port->mon_data.modem_status = status;

  	wake_up_interruptible(&port->port.delta_msr_wait);

  	if ((port->port.flags & ASYNC_CHECK_CD) && (status & UART_MSR_DDCD)) {

  		if (status & UART_MSR_DCD)

  			wake_up_interruptible(&port->port.open_wait);

  	}

  	if (port->port.flags & ASYNC_CTS_FLOW) {

  		if (tty->hw_stopped) {

  			if (status & UART_MSR_CTS) {

  				tty->hw_stopped = 0;

  
  				if ((port->type != PORT_16550A) &&
  						(!port->board->chip_flag)) {
  					outb(port->IER & ~UART_IER_THRI,
  						port->ioaddr + UART_IER);
  					port->IER |= UART_IER_THRI;
  					outb(port->IER, port->ioaddr +
  							UART_IER);
  				}

  				tty_wakeup(tty);

  			}
  		} else {
  			if (!(status & UART_MSR_CTS)) {

  				tty->hw_stopped = 1;

  				if (port->type != PORT_16550A &&
  						!port->board->chip_flag) {
  					port->IER &= ~UART_IER_THRI;
  					outb(port->IER, port->ioaddr +
  							UART_IER);
  				}
  			}
  		}

  	}
  }

  static int mxser_activate(struct tty_port *port, struct tty_struct *tty)

  {

  	struct mxser_port *info = container_of(port, struct mxser_port, port);

  	unsigned long page;
  	unsigned long flags;

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

  	spin_lock_irqsave(&info->slock, flags);

  	if (!info->ioaddr || !info->type) {

  		set_bit(TTY_IO_ERROR, &tty->flags);

  		free_page(page);
  		spin_unlock_irqrestore(&info->slock, flags);

  		return 0;

  	}

  	info->port.xmit_buf = (unsigned char *) page;

  	/*

  	 * Clear the FIFO buffers and disable them
  	 * (they will be reenabled in mxser_change_speed())

  	 */

  	if (info->board->chip_flag)
  		outb((UART_FCR_CLEAR_RCVR |
  			UART_FCR_CLEAR_XMIT |
  			MOXA_MUST_FCR_GDA_MODE_ENABLE), info->ioaddr + UART_FCR);
  	else
  		outb((UART_FCR_CLEAR_RCVR | UART_FCR_CLEAR_XMIT),
  			info->ioaddr + UART_FCR);

  	/*
  	 * At this point there's no way the LSR could still be 0xFF;
  	 * if it is, then bail out, because there's likely no UART
  	 * here.
  	 */
  	if (inb(info->ioaddr + UART_LSR) == 0xff) {
  		spin_unlock_irqrestore(&info->slock, flags);
  		if (capable(CAP_SYS_ADMIN)) {

  			set_bit(TTY_IO_ERROR, &tty->flags);

  			return 0;
  		} else
  			return -ENODEV;
  	}

  	/*
  	 * Clear the interrupt registers.
  	 */
  	(void) inb(info->ioaddr + UART_LSR);
  	(void) inb(info->ioaddr + UART_RX);
  	(void) inb(info->ioaddr + UART_IIR);
  	(void) inb(info->ioaddr + UART_MSR);
  
  	/*
  	 * Now, initialize the UART
  	 */
  	outb(UART_LCR_WLEN8, info->ioaddr + UART_LCR);	/* reset DLAB */
  	info->MCR = UART_MCR_DTR | UART_MCR_RTS;
  	outb(info->MCR, info->ioaddr + UART_MCR);
  
  	/*
  	 * Finally, enable interrupts
  	 */
  	info->IER = UART_IER_MSI | UART_IER_RLSI | UART_IER_RDI;
  
  	if (info->board->chip_flag)
  		info->IER |= MOXA_MUST_IER_EGDAI;
  	outb(info->IER, info->ioaddr + UART_IER);	/* enable interrupts */
  
  	/*
  	 * And clear the interrupt registers again for luck.
  	 */
  	(void) inb(info->ioaddr + UART_LSR);
  	(void) inb(info->ioaddr + UART_RX);
  	(void) inb(info->ioaddr + UART_IIR);
  	(void) inb(info->ioaddr + UART_MSR);

  	clear_bit(TTY_IO_ERROR, &tty->flags);

  	info->xmit_cnt = info->xmit_head = info->xmit_tail = 0;
  
  	/*
  	 * and set the speed of the serial port
  	 */

  	mxser_change_speed(tty, NULL);

  	spin_unlock_irqrestore(&info->slock, flags);
  
  	return 0;
  }
  
  /*

   * This routine will shutdown a serial port

   */

  static void mxser_shutdown_port(struct tty_port *port)

  {

  	struct mxser_port *info = container_of(port, struct mxser_port, port);

  	unsigned long flags;

  	spin_lock_irqsave(&info->slock, 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->port.delta_msr_wait);

  
  	/*

  	 * Free the xmit buffer, if necessary

  	 */

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

  	}

  	info->IER = 0;
  	outb(0x00, info->ioaddr + UART_IER);

  	/* clear Rx/Tx FIFO's */
  	if (info->board->chip_flag)
  		outb(UART_FCR_CLEAR_RCVR | UART_FCR_CLEAR_XMIT |
  				MOXA_MUST_FCR_GDA_MODE_ENABLE,
  				info->ioaddr + UART_FCR);
  	else
  		outb(UART_FCR_CLEAR_RCVR | UART_FCR_CLEAR_XMIT,
  			info->ioaddr + UART_FCR);
  
  	/* read data port to reset things */
  	(void) inb(info->ioaddr + UART_RX);

  
  	if (info->board->chip_flag)
  		SET_MOXA_MUST_NO_SOFTWARE_FLOW_CONTROL(info->ioaddr);
  
  	spin_unlock_irqrestore(&info->slock, flags);
  }
  
  /*
   * 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 mxser_open(struct tty_struct *tty, struct file *filp)
  {
  	struct mxser_port *info;

  	int line;

  
  	line = tty->index;
  	if (line == MXSER_PORTS)
  		return 0;
  	if (line < 0 || line > MXSER_PORTS)
  		return -ENODEV;
  	info = &mxser_boards[line / MXSER_PORTS_PER_BOARD].ports[line % MXSER_PORTS_PER_BOARD];
  	if (!info->ioaddr)
  		return -ENODEV;

  	tty->driver_data = info;

  	return tty_port_open(&info->port, tty, filp);

  }

  static void mxser_flush_buffer(struct tty_struct *tty)
  {
  	struct mxser_port *info = tty->driver_data;
  	char fcr;
  	unsigned long flags;
  
  
  	spin_lock_irqsave(&info->slock, flags);
  	info->xmit_cnt = info->xmit_head = info->xmit_tail = 0;
  
  	fcr = inb(info->ioaddr + UART_FCR);
  	outb((fcr | UART_FCR_CLEAR_RCVR | UART_FCR_CLEAR_XMIT),
  		info->ioaddr + UART_FCR);
  	outb(fcr, info->ioaddr + UART_FCR);
  
  	spin_unlock_irqrestore(&info->slock, flags);
  
  	tty_wakeup(tty);
  }

  static void mxser_close_port(struct tty_port *port)

  {

  	struct mxser_port *info = container_of(port, struct mxser_port, port);

  	unsigned long timeout;

  	/*

  	 * 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;

  	if (info->board->chip_flag)

  		info->IER &= ~MOXA_MUST_RECV_ISR;

  	outb(info->IER, info->ioaddr + UART_IER);
  	/*
  	 * Before we drop DTR, make sure the UART transmitter
  	 * has completely drained; this is especially
  	 * important if there is a transmit FIFO!
  	 */
  	timeout = jiffies + HZ;
  	while (!(inb(info->ioaddr + UART_LSR) & UART_LSR_TEMT)) {
  		schedule_timeout_interruptible(5);
  		if (time_after(jiffies, timeout))
  			break;

  	}

  }
  
  /*
   * 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 mxser_close(struct tty_struct *tty, struct file *filp)
  {
  	struct mxser_port *info = tty->driver_data;
  	struct tty_port *port = &info->port;

  	if (tty->index == MXSER_PORTS || info == NULL)

  		return;
  	if (tty_port_close_start(port, tty, filp) == 0)
  		return;

  	mutex_lock(&port->mutex);
  	mxser_close_port(port);

  	mxser_flush_buffer(tty);

  	mxser_shutdown_port(port);
  	clear_bit(ASYNCB_INITIALIZED, &port->flags);
  	mutex_unlock(&port->mutex);

  	/* Right now the tty_port set is done outside of the close_end helper
  	   as we don't yet have everyone using refcounts */	
  	tty_port_close_end(port, tty);
  	tty_port_tty_set(port, NULL);

  }
  
  static int mxser_write(struct tty_struct *tty, const unsigned char *buf, int count)
  {
  	int c, total = 0;

  	struct mxser_port *info = tty->driver_data;

  	unsigned long flags;

  	if (!info->port.xmit_buf)

  		return 0;

  
  	while (1) {

  		c = min_t(int, count, min(SERIAL_XMIT_SIZE - info->xmit_cnt - 1,
  					  SERIAL_XMIT_SIZE - info->xmit_head));

  		if (c <= 0)
  			break;

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

  		spin_lock_irqsave(&info->slock, flags);

  		info->xmit_head = (info->xmit_head + c) &
  				  (SERIAL_XMIT_SIZE - 1);

  		info->xmit_cnt += c;
  		spin_unlock_irqrestore(&info->slock, flags);
  
  		buf += c;
  		count -= c;
  		total += c;

  	}

  	if (info->xmit_cnt && !tty->stopped) {

  		if (!tty->hw_stopped ||
  				(info->type == PORT_16550A) ||

  				(info->board->chip_flag)) {

  			spin_lock_irqsave(&info->slock, flags);

  			outb(info->IER & ~UART_IER_THRI, info->ioaddr +
  					UART_IER);

  			info->IER |= UART_IER_THRI;

  			outb(info->IER, info->ioaddr + UART_IER);

  			spin_unlock_irqrestore(&info->slock, flags);
  		}
  	}
  	return total;
  }

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

  {

  	struct mxser_port *info = tty->driver_data;

  	unsigned long flags;

  	if (!info->port.xmit_buf)

  		return 0;

  
  	if (info->xmit_cnt >= SERIAL_XMIT_SIZE - 1)

  		return 0;

  
  	spin_lock_irqsave(&info->slock, flags);

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

  	info->xmit_head &= SERIAL_XMIT_SIZE - 1;
  	info->xmit_cnt++;
  	spin_unlock_irqrestore(&info->slock, flags);

  	if (!tty->stopped) {

  		if (!tty->hw_stopped ||
  				(info->type == PORT_16550A) ||

  				info->board->chip_flag) {

  			spin_lock_irqsave(&info->slock, flags);

  			outb(info->IER & ~UART_IER_THRI, info->ioaddr + UART_IER);

  			info->IER |= UART_IER_THRI;

  			outb(info->IER, info->ioaddr + UART_IER);

  			spin_unlock_irqrestore(&info->slock, flags);
  		}
  	}

  	return 1;

  }
  
  
  static void mxser_flush_chars(struct tty_struct *tty)
  {

  	struct mxser_port *info = tty->driver_data;

  	unsigned long flags;

  	if (info->xmit_cnt <= 0 || tty->stopped || !info->port.xmit_buf ||
  			(tty->hw_stopped && info->type != PORT_16550A &&
  			 !info->board->chip_flag))

  		return;
  
  	spin_lock_irqsave(&info->slock, flags);

  	outb(info->IER & ~UART_IER_THRI, info->ioaddr + UART_IER);

  	info->IER |= UART_IER_THRI;

  	outb(info->IER, info->ioaddr + UART_IER);

  
  	spin_unlock_irqrestore(&info->slock, flags);
  }
  
  static int mxser_write_room(struct tty_struct *tty)
  {

  	struct mxser_port *info = tty->driver_data;

  	int ret;
  
  	ret = SERIAL_XMIT_SIZE - info->xmit_cnt - 1;

  	return ret < 0 ? 0 : ret;

  }
  
  static int mxser_chars_in_buffer(struct tty_struct *tty)
  {

  	struct mxser_port *info = tty->driver_data;

  	return info->xmit_cnt;
  }

  /*
   * ------------------------------------------------------------
   * friends of mxser_ioctl()
   * ------------------------------------------------------------
   */

  static int mxser_get_serial_info(struct tty_struct *tty,

  		struct serial_struct __user *retinfo)
  {

  	struct mxser_port *info = tty->driver_data;

  	struct serial_struct tmp = {
  		.type = info->type,

  		.line = tty->index,

  		.port = info->ioaddr,
  		.irq = info->board->irq,

  		.flags = info->port.flags,

  		.baud_base = info->baud_base,

  		.close_delay = info->port.close_delay,
  		.closing_wait = info->port.closing_wait,

  		.custom_divisor = info->custom_divisor,
  		.hub6 = 0
  	};
  	if (copy_to_user(retinfo, &tmp, sizeof(*retinfo)))
  		return -EFAULT;
  	return 0;
  }

  static int mxser_set_serial_info(struct tty_struct *tty,

  		struct serial_struct __user *new_info)

  {

  	struct mxser_port *info = tty->driver_data;

  	struct tty_port *port = &info->port;

  	struct serial_struct new_serial;

  	speed_t baud;

  	unsigned long sl_flags;
  	unsigned int flags;
  	int retval = 0;

  	if (!new_info || !info->ioaddr)

  		return -ENODEV;

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

  	if (new_serial.irq != info->board->irq ||
  			new_serial.port != info->ioaddr)
  		return -EINVAL;

  	flags = port->flags & ASYNC_SPD_MASK;

  	if (!capable(CAP_SYS_ADMIN)) {
  		if ((new_serial.baud_base != info->baud_base) ||

  				(new_serial.close_delay != info->port.close_delay) ||

  				((new_serial.flags & ~ASYNC_USR_MASK) != (info->port.flags & ~ASYNC_USR_MASK)))

  			return -EPERM;

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

  				(new_serial.flags & ASYNC_USR_MASK));
  	} else {

  		/*

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

  		 */

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

  				(new_serial.flags & ASYNC_FLAGS));

  		port->close_delay = new_serial.close_delay * HZ / 100;
  		port->closing_wait = new_serial.closing_wait * HZ / 100;
  		tty->low_latency = (port->flags & ASYNC_LOW_LATENCY) ? 1 : 0;
  		if ((port->flags & ASYNC_SPD_MASK) == ASYNC_SPD_CUST &&

  				(new_serial.baud_base != info->baud_base ||
  				new_serial.custom_divisor !=
  				info->custom_divisor)) {

  			if (new_serial.custom_divisor == 0)
  				return -EINVAL;

  			baud = new_serial.baud_base / new_serial.custom_divisor;

  			tty_encode_baud_rate(tty, baud, baud);

  		}

  	}

  	info->type = new_serial.type;

  	process_txrx_fifo(info);

  	if (test_bit(ASYNCB_INITIALIZED, &port->flags)) {
  		if (flags != (port->flags & ASYNC_SPD_MASK)) {

  			spin_lock_irqsave(&info->slock, sl_flags);

  			mxser_change_speed(tty, NULL);

  			spin_unlock_irqrestore(&info->slock, sl_flags);

  		}

  	} else {

  		retval = mxser_activate(port, tty);

  		if (retval == 0)

  			set_bit(ASYNCB_INITIALIZED, &port->flags);

  	}

  	return retval;
  }

  /*
   * mxser_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 mxser_get_lsr_info(struct mxser_port *info,
  		unsigned int __user *value)
  {
  	unsigned char status;
  	unsigned int result;
  	unsigned long flags;

  	spin_lock_irqsave(&info->slock, flags);
  	status = inb(info->ioaddr + UART_LSR);
  	spin_unlock_irqrestore(&info->slock, flags);
  	result = ((status & UART_LSR_TEMT) ? TIOCSER_TEMT : 0);
  	return put_user(result, value);
  }

  static int mxser_tiocmget(struct tty_struct *tty)

  {
  	struct mxser_port *info = tty->driver_data;
  	unsigned char control, status;
  	unsigned long flags;

  	if (tty->index == MXSER_PORTS)
  		return -ENOIOCTLCMD;
  	if (test_bit(TTY_IO_ERROR, &tty->flags))
  		return -EIO;

  	control = info->MCR;

  	spin_lock_irqsave(&info->slock, flags);
  	status = inb(info->ioaddr + UART_MSR);
  	if (status & UART_MSR_ANY_DELTA)

  		mxser_check_modem_status(tty, info, status);

  	spin_unlock_irqrestore(&info->slock, 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 mxser_tiocmset(struct tty_struct *tty,

  		unsigned int set, unsigned int clear)
  {
  	struct mxser_port *info = tty->driver_data;
  	unsigned long flags;

  	if (tty->index == MXSER_PORTS)
  		return -ENOIOCTLCMD;
  	if (test_bit(TTY_IO_ERROR, &tty->flags))
  		return -EIO;

  	spin_lock_irqsave(&info->slock, 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;

  	outb(info->MCR, info->ioaddr + UART_MCR);
  	spin_unlock_irqrestore(&info->slock, flags);
  	return 0;
  }

  static int __init mxser_program_mode(int port)
  {
  	int id, i, j, n;
  
  	outb(0, port);
  	outb(0, port);
  	outb(0, port);
  	(void)inb(port);
  	(void)inb(port);
  	outb(0, port);
  	(void)inb(port);
  
  	id = inb(port + 1) & 0x1F;
  	if ((id != C168_ASIC_ID) &&
  			(id != C104_ASIC_ID) &&
  			(id != C102_ASIC_ID) &&
  			(id != CI132_ASIC_ID) &&
  			(id != CI134_ASIC_ID) &&
  			(id != CI104J_ASIC_ID))
  		return -1;
  	for (i = 0, j = 0; i < 4; i++) {
  		n = inb(port + 2);
  		if (n == 'M') {
  			j = 1;
  		} else if ((j == 1) && (n == 1)) {
  			j = 2;
  			break;
  		} else
  			j = 0;

  	}

  	if (j != 2)
  		id = -2;
  	return id;

  }

  static void __init mxser_normal_mode(int port)
  {
  	int i, n;
  
  	outb(0xA5, port + 1);
  	outb(0x80, port + 3);
  	outb(12, port + 0);	/* 9600 bps */
  	outb(0, port + 1);
  	outb(0x03, port + 3);	/* 8 data bits */
  	outb(0x13, port + 4);	/* loop back mode */
  	for (i = 0; i < 16; i++) {
  		n = inb(port + 5);
  		if ((n & 0x61) == 0x60)
  			break;
  		if ((n & 1) == 1)
  			(void)inb(port);
  	}
  	outb(0x00, port + 4);
  }
  
  #define CHIP_SK 	0x01	/* Serial Data Clock  in Eprom */
  #define CHIP_DO 	0x02	/* Serial Data Output in Eprom */
  #define CHIP_CS 	0x04	/* Serial Chip Select in Eprom */
  #define CHIP_DI 	0x08	/* Serial Data Input  in Eprom */
  #define EN_CCMD 	0x000	/* Chip's command register     */
  #define EN0_RSARLO	0x008	/* Remote start address reg 0  */
  #define EN0_RSARHI	0x009	/* Remote start address reg 1  */
  #define EN0_RCNTLO	0x00A	/* Remote byte count reg WR    */
  #define EN0_RCNTHI	0x00B	/* Remote byte count reg WR    */
  #define EN0_DCFG	0x00E	/* Data configuration reg WR   */
  #define EN0_PORT	0x010	/* Rcv missed frame error counter RD */
  #define ENC_PAGE0	0x000	/* Select page 0 of chip registers   */
  #define ENC_PAGE3	0x0C0	/* Select page 3 of chip registers   */
  static int __init mxser_read_register(int port, unsigned short *regs)
  {
  	int i, k, value, id;
  	unsigned int j;
  
  	id = mxser_program_mode(port);
  	if (id < 0)
  		return id;
  	for (i = 0; i < 14; i++) {
  		k = (i & 0x3F) | 0x180;
  		for (j = 0x100; j > 0; j >>= 1) {
  			outb(CHIP_CS, port);
  			if (k & j) {
  				outb(CHIP_CS | CHIP_DO, port);
  				outb(CHIP_CS | CHIP_DO | CHIP_SK, port);	/* A? bit of read */
  			} else {
  				outb(CHIP_CS, port);
  				outb(CHIP_CS | CHIP_SK, port);	/* A? bit of read */
  			}
  		}
  		(void)inb(port);
  		value = 0;
  		for (k = 0, j = 0x8000; k < 16; k++, j >>= 1) {
  			outb(CHIP_CS, port);
  			outb(CHIP_CS | CHIP_SK, port);
  			if (inb(port) & CHIP_DI)
  				value |= j;
  		}
  		regs[i] = value;
  		outb(0, port);
  	}
  	mxser_normal_mode(port);
  	return id;
  }

  
  static int mxser_ioctl_special(unsigned int cmd, void __user *argp)
  {

  	struct mxser_port *ip;
  	struct tty_port *port;

  	struct tty_struct *tty;

  	int result, status;
  	unsigned int i, j;

  	int ret = 0;

  
  	switch (cmd) {

  	case MOXA_GET_MAJOR:

  		printk_ratelimited(KERN_WARNING "mxser: '%s' uses deprecated ioctl "

  					"%x (GET_MAJOR), fix your userspace
  ",
  					current->comm, cmd);

  		return put_user(ttymajor, (int __user *)argp);

  
  	case MOXA_CHKPORTENABLE:
  		result = 0;

  		for (i = 0; i < MXSER_BOARDS; i++)
  			for (j = 0; j < MXSER_PORTS_PER_BOARD; j++)
  				if (mxser_boards[i].ports[j].ioaddr)
  					result |= (1 << i);

  		return put_user(result, (unsigned long __user *)argp);

  	case MOXA_GETDATACOUNT:

  		/* The receive side is locked by port->slock but it isn't
  		   clear that an exact snapshot is worth copying here */

  		if (copy_to_user(argp, &mxvar_log, sizeof(mxvar_log)))

  			ret = -EFAULT;

  		return ret;

  	case MOXA_GETMSTATUS: {
  		struct mxser_mstatus ms, __user *msu = argp;

  		for (i = 0; i < MXSER_BOARDS; i++)
  			for (j = 0; j < MXSER_PORTS_PER_BOARD; j++) {

  				ip = &mxser_boards[i].ports[j];
  				port = &ip->port;

  				memset(&ms, 0, sizeof(ms));

  				mutex_lock(&port->mutex);
  				if (!ip->ioaddr)

  					goto copy;

  				tty = tty_port_tty_get(port);

  				if (!tty || !tty->termios)

  					ms.cflag = ip->normal_termios.c_cflag;

  				else

  					ms.cflag = tty->termios->c_cflag;
  				tty_kref_put(tty);

  				spin_lock_irq(&ip->slock);
  				status = inb(ip->ioaddr + UART_MSR);
  				spin_unlock_irq(&ip->slock);

  				if (status & UART_MSR_DCD)
  					ms.dcd = 1;
  				if (status & UART_MSR_DSR)
  					ms.dsr = 1;
  				if (status & UART_MSR_CTS)
  					ms.cts = 1;
  			copy:

  				mutex_unlock(&port->mutex);
  				if (copy_to_user(msu, &ms, sizeof(ms)))

  					return -EFAULT;

  				msu++;

  			}

  		return 0;

  	}

  	case MOXA_ASPP_MON_EXT: {

  		struct mxser_mon_ext *me; /* it's 2k, stack unfriendly */
  		unsigned int cflag, iflag, p;
  		u8 opmode;
  
  		me = kzalloc(sizeof(*me), GFP_KERNEL);
  		if (!me)
  			return -ENOMEM;

  		for (i = 0, p = 0; i < MXSER_BOARDS; i++) {
  			for (j = 0; j < MXSER_PORTS_PER_BOARD; j++, p++) {
  				if (p >= ARRAY_SIZE(me->rx_cnt)) {
  					i = MXSER_BOARDS;
  					break;
  				}

  				ip = &mxser_boards[i].ports[j];
  				port = &ip->port;
  
  				mutex_lock(&port->mutex);
  				if (!ip->ioaddr) {
  					mutex_unlock(&port->mutex);

  					continue;

  				}

  				spin_lock_irq(&ip->slock);
  				status = mxser_get_msr(ip->ioaddr, 0, p);

  				if (status & UART_MSR_TERI)

  					ip->icount.rng++;

  				if (status & UART_MSR_DDSR)

  					ip->icount.dsr++;

  				if (status & UART_MSR_DDCD)

  					ip->icount.dcd++;

  				if (status & UART_MSR_DCTS)

  					ip->icount.cts++;

  				ip->mon_data.modem_status = status;
  				me->rx_cnt[p] = ip->mon_data.rxcnt;
  				me->tx_cnt[p] = ip->mon_data.txcnt;
  				me->up_rxcnt[p] = ip->mon_data.up_rxcnt;
  				me->up_txcnt[p] = ip->mon_data.up_txcnt;

  				me->modem_status[p] =

  					ip->mon_data.modem_status;
  				spin_unlock_irq(&ip->slock);
  
  				tty = tty_port_tty_get(&ip->port);

  				if (!tty || !tty->termios) {

  					cflag = ip->normal_termios.c_cflag;
  					iflag = ip->normal_termios.c_iflag;
  					me->baudrate[p] = tty_termios_baud_rate(&ip->normal_termios);

  				} else {

  					cflag = tty->termios->c_cflag;
  					iflag = tty->termios->c_iflag;
  					me->baudrate[p] = tty_get_baud_rate(tty);

  				}

  				tty_kref_put(tty);

  				me->databits[p] = cflag & CSIZE;
  				me->stopbits[p] = cflag & CSTOPB;
  				me->parity[p] = cflag & (PARENB | PARODD |
  						CMSPAR);

  
  				if (cflag & CRTSCTS)

  					me->flowctrl[p] |= 0x03;

  
  				if (iflag & (IXON | IXOFF))

  					me->flowctrl[p] |= 0x0C;

  				if (ip->type == PORT_16550A)

  					me->fifo[p] = 1;

  				opmode = inb(ip->opmode_ioaddr)>>((p % 4) * 2);

  				opmode &= OP_MODE_MASK;

  				me->iftype[p] = opmode;

  				mutex_unlock(&port->mutex);

  			}

  		}

  		if (copy_to_user(argp, me, sizeof(*me)))
  			ret = -EFAULT;
  		kfree(me);
  		return ret;

  	}
  	default:

  		return -ENOIOCTLCMD;
  	}
  	return 0;
  }

  static int mxser_cflags_changed(struct mxser_port *info, unsigned long arg,
  		struct async_icount *cprev)

  {

  	struct async_icount cnow;
  	unsigned long flags;
  	int ret;

  	spin_lock_irqsave(&info->slock, flags);
  	cnow = info->icount;	/* atomic copy */
  	spin_unlock_irqrestore(&info->slock, flags);

  	ret =	((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));

  	*cprev = cnow;
  
  	return ret;
  }

  static int mxser_ioctl(struct tty_struct *tty,

  		unsigned int cmd, unsigned long arg)

  {

  	struct mxser_port *info = tty->driver_data;

  	struct tty_port *port = &info->port;

  	struct async_icount cnow;

  	unsigned long flags;
  	void __user *argp = (void __user *)arg;
  	int retval;

  	if (tty->index == MXSER_PORTS)
  		return mxser_ioctl_special(cmd, argp);

  	if (cmd == MOXA_SET_OP_MODE || cmd == MOXA_GET_OP_MODE) {
  		int p;
  		unsigned long opmode;
  		static unsigned char ModeMask[] = { 0xfc, 0xf3, 0xcf, 0x3f };
  		int shiftbit;
  		unsigned char val, mask;

  		p = tty->index % 4;
  		if (cmd == MOXA_SET_OP_MODE) {
  			if (get_user(opmode, (int __user *) argp))
  				return -EFAULT;
  			if (opmode != RS232_MODE &&
  					opmode != RS485_2WIRE_MODE &&
  					opmode != RS422_MODE &&
  					opmode != RS485_4WIRE_MODE)
  				return -EFAULT;
  			mask = ModeMask[p];
  			shiftbit = p * 2;

  			spin_lock_irq(&info->slock);

  			val = inb(info->opmode_ioaddr);
  			val &= mask;
  			val |= (opmode << shiftbit);
  			outb(val, info->opmode_ioaddr);

  			spin_unlock_irq(&info->slock);

  		} else {
  			shiftbit = p * 2;

  			spin_lock_irq(&info->slock);

  			opmode = inb(info->opmode_ioaddr) >> shiftbit;

  			spin_unlock_irq(&info->slock);

  			opmode &= OP_MODE_MASK;
  			if (put_user(opmode, (int __user *)argp))
  				return -EFAULT;
  		}
  		return 0;
  	}

  	if (cmd != TIOCGSERIAL && cmd != TIOCMIWAIT &&

  			test_bit(TTY_IO_ERROR, &tty->flags))
  		return -EIO;
  
  	switch (cmd) {

  	case TIOCGSERIAL:

  		mutex_lock(&port->mutex);

  		retval = mxser_get_serial_info(tty, argp);

  		mutex_unlock(&port->mutex);

  		return retval;

  	case TIOCSSERIAL:

  		mutex_lock(&port->mutex);

  		retval = mxser_set_serial_info(tty, argp);

  		mutex_unlock(&port->mutex);

  		return retval;

  	case TIOCSERGETLSR:	/* Get line status register */

  		return  mxser_get_lsr_info(info, argp);

  		/*
  		 * 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->slock, flags);
  		cnow = info->icount;	/* note the counters on entry */
  		spin_unlock_irqrestore(&info->slock, flags);

  		return wait_event_interruptible(info->port.delta_msr_wait,

  				mxser_cflags_changed(info, arg, &cnow));

  	case MOXA_HighSpeedOn:
  		return put_user(info->baud_base != 115200 ? 1 : 0, (int __user *)argp);
  	case MOXA_SDS_RSTICOUNTER:

  		spin_lock_irq(&info->slock);

  		info->mon_data.rxcnt = 0;
  		info->mon_data.txcnt = 0;

  		spin_unlock_irq(&info->slock);

  		return 0;
  
  	case MOXA_ASPP_OQUEUE:{
  		int len, lsr;
  
  		len = mxser_chars_in_buffer(tty);

  		spin_lock_irq(&info->slock);

  		lsr = inb(info->ioaddr + UART_LSR) & UART_LSR_THRE;

  		spin_unlock_irq(&info->slock);

  		len += (lsr ? 0 : 1);
  
  		return put_user(len, (int __user *)argp);
  	}
  	case MOXA_ASPP_MON: {
  		int mcr, status;

  		spin_lock_irq(&info->slock);

  		status = mxser_get_msr(info->ioaddr, 1, tty->index);

  		mxser_check_modem_status(tty, info, status);

  
  		mcr = inb(info->ioaddr + UART_MCR);

  		spin_unlock_irq(&info->slock);

  		if (mcr & MOXA_MUST_MCR_XON_FLAG)
  			info->mon_data.hold_reason &= ~NPPI_NOTIFY_XOFFHOLD;
  		else
  			info->mon_data.hold_reason |= NPPI_NOTIFY_XOFFHOLD;
  
  		if (mcr & MOXA_MUST_MCR_TX_XON)
  			info->mon_data.hold_reason &= ~NPPI_NOTIFY_XOFFXENT;
  		else
  			info->mon_data.hold_reason |= NPPI_NOTIFY_XOFFXENT;

  		if (tty->hw_stopped)

  			info->mon_data.hold_reason |= NPPI_NOTIFY_CTSHOLD;
  		else
  			info->mon_data.hold_reason &= ~NPPI_NOTIFY_CTSHOLD;

  		if (copy_to_user(argp, &info->mon_data,
  				sizeof(struct mxser_mon)))
  			return -EFAULT;
  
  		return 0;
  	}
  	case MOXA_ASPP_LSTATUS: {
  		if (put_user(info->err_shadow, (unsigned char __user *)argp))
  			return -EFAULT;
  
  		info->err_shadow = 0;
  		return 0;
  	}
  	case MOXA_SET_BAUD_METHOD: {
  		int method;
  
  		if (get_user(method, (int __user *)argp))
  			return -EFAULT;
  		mxser_set_baud_method[tty->index] = method;
  		return put_user(method, (int __user *)argp);
  	}
  	default:
  		return -ENOIOCTLCMD;
  	}
  	return 0;
  }

  	/*
  	 * 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.
  	 */
  
  static int mxser_get_icount(struct tty_struct *tty,
  		struct serial_icounter_struct *icount)
  
  {
  	struct mxser_port *info = tty->driver_data;
  	struct async_icount cnow;
  	unsigned long flags;
  
  	spin_lock_irqsave(&info->slock, flags);
  	cnow = info->icount;
  	spin_unlock_irqrestore(&info->slock, flags);
  
  	icount->frame = cnow.frame;
  	icount->brk = cnow.brk;
  	icount->overrun = cnow.overrun;
  	icount->buf_overrun = cnow.buf_overrun;
  	icount->parity = cnow.parity;
  	icount->rx = cnow.rx;
  	icount->tx = cnow.tx;
  	icount->cts = cnow.cts;
  	icount->dsr = cnow.dsr;
  	icount->rng = cnow.rng;
  	icount->dcd = cnow.dcd;
  	return 0;
  }

  static void mxser_stoprx(struct tty_struct *tty)
  {
  	struct mxser_port *info = tty->driver_data;
  
  	info->ldisc_stop_rx = 1;
  	if (I_IXOFF(tty)) {
  		if (info->board->chip_flag) {
  			info->IER &= ~MOXA_MUST_RECV_ISR;
  			outb(info->IER, info->ioaddr + UART_IER);
  		} else {
  			info->x_char = STOP_CHAR(tty);
  			outb(0, info->ioaddr + UART_IER);
  			info->IER |= UART_IER_THRI;
  			outb(info->IER, info->ioaddr + UART_IER);

  		}
  	}

  	if (tty->termios->c_cflag & CRTSCTS) {

  		info->MCR &= ~UART_MCR_RTS;
  		outb(info->MCR, info->ioaddr + UART_MCR);

  	}
  }
  
  /*
   * This routine is called by the upper-layer tty layer to signal that
   * incoming characters should be throttled.
   */
  static void mxser_throttle(struct tty_struct *tty)
  {

  	mxser_stoprx(tty);

  }
  
  static void mxser_unthrottle(struct tty_struct *tty)
  {

  	struct mxser_port *info = tty->driver_data;

  	/* startrx */
  	info->ldisc_stop_rx = 0;
  	if (I_IXOFF(tty)) {
  		if (info->x_char)
  			info->x_char = 0;
  		else {
  			if (info->board->chip_flag) {
  				info->IER |= MOXA_MUST_RECV_ISR;
  				outb(info->IER, info->ioaddr + UART_IER);
  			} else {
  				info->x_char = START_CHAR(tty);
  				outb(0, info->ioaddr + UART_IER);
  				info->IER |= UART_IER_THRI;
  				outb(info->IER, info->ioaddr + UART_IER);
  			}

  		}