// SPDX-License-Identifier: GPL-2.0+
/*
 *          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.
 *
 *      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/io.h>
#include <asm/irq.h>
#include <linux/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 const 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_hw_array(ioaddr, ulong, ioport, 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 */
        unsigned int timeout;

        int read_status_mask;
        int ignore_status_mask;
        unsigned int xmit_fifo_size;
        int xmit_head;
        int xmit_tail;
        int xmit_cnt;
        int closing;

        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 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;
        unsigned int quot = 0, baud;
        unsigned char cval;
        u64 timeout;

        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;
        }

        /*
         * worst case (128 * 1000 * 10 * 18432) needs 35 bits, so divide in the
         * u64 domain
         */
        timeout = (u64)info->xmit_fifo_size * HZ * 10 * quot;
        do_div(timeout, info->baud_base);
        info->timeout = 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 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;
        tty_port_set_cts_flow(&info->port, cflag & CRTSCTS);
        if (cflag & CRTSCTS) {
                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);
                                        }
                                }
                        }
                }
        }
        outb(info->MCR, info->ioaddr + UART_MCR);
        tty_port_set_check_carrier(&info->port, ~cflag & CLOCAL);
        if (~cflag & CLOCAL)
                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 (tty_port_check_carrier(&port->port) && (status & UART_MSR_DDCD)) {
                if (status & UART_MSR_DCD)
                        wake_up_interruptible(&port->port.open_wait);
        }

        if (tty_port_cts_enabled(&port->port)) {
                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);
        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;
        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;
        info->closing = 1;
        mutex_lock(&port->mutex);
        mxser_close_port(port);
        mxser_flush_buffer(tty);
        if (tty_port_initialized(port) && C_HUPCL(tty))
                tty_port_lower_dtr_rts(port);
        mxser_shutdown_port(port);
        tty_port_set_initialized(port, 0);
        mutex_unlock(&port->mutex);
        info->closing = 0;
        /* 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,
        };
        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;
                port->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 (tty_port_initialized(port)) {
                if (flags != (port->flags & ASYNC_SPD_MASK)) {
                        spin_lock_irqsave(&info->slock, sl_flags);
                        mxser_change_speed(tty);
                        spin_unlock_irqrestore(&info->slock, sl_flags);
                }
        } else {
                retval = mxser_activate(port, tty);
                if (retval == 0)
                        tty_port_set_initialized(port, 1);
        }
        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 (tty_io_error(tty))
                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 (tty_io_error(tty))
                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\n",
                                        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)
                                        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) {
                                        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;

                                if (ip->board->chip_flag == MOXA_MUST_MU860_HWID) {
                                        opmode = inb(ip->opmode_ioaddr)>>((p % 4) * 2);
                                        opmode &= OP_MODE_MASK;
                                } else {
                                        opmode = RS232_MODE;
                                }
                                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;

                if (info->board->chip_flag != MOXA_MUST_MU860_HWID)
                        return -EFAULT;

                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 && tty_io_error(tty))
                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 (C_CRTSCTS(tty)) {
                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);
                        }
                }
        }

        if (C_CRTSCTS(tty)) {
                info->MCR |= UART_MCR_RTS;
                outb(info->MCR, info->ioaddr + UART_MCR);
        }
}

/*
 * mxser_stop() and mxser_start()
 *
 * This routines are called before setting or resetting tty->stopped.
 * They enable or disable transmitter interrupts, as necessary.
 */
static void mxser_stop(struct tty_struct *tty)
{
        struct mxser_port *info = tty->driver_data;
        unsigned long flags;

        spin_lock_irqsave(&info->slock, flags);
        if (info->IER & UART_IER_THRI) {
                info->IER &= ~UART_IER_THRI;
                outb(info->IER, info->ioaddr + UART_IER);
        }
        spin_unlock_irqrestore(&info->slock, flags);
}

static void mxser_start(struct tty_struct *tty)
{
        struct mxser_port *info = tty->driver_data;
        unsigned long flags;

        spin_lock_irqsave(&info->slock, flags);
        if (info->xmit_cnt && info->port.xmit_buf) {
                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 void mxser_set_termios(struct tty_struct *tty, struct ktermios *old_termios)
{
        struct mxser_port *info = tty->driver_data;
        unsigned long flags;

        spin_lock_irqsave(&info->slock, flags);
        mxser_change_speed(tty);
        spin_unlock_irqrestore(&info->slock, flags);

        if ((old_termios->c_cflag & CRTSCTS) && !C_CRTSCTS(tty)) {
                tty->hw_stopped = 0;
                mxser_start(tty);
        }

        /* Handle sw stopped */
        if ((old_termios->c_iflag & IXON) && !I_IXON(tty)) {
                tty->stopped = 0;

                if (info->board->chip_flag) {
                        spin_lock_irqsave(&info->slock, flags);
                        mxser_disable_must_rx_software_flow_control(
                                        info->ioaddr);
                        spin_unlock_irqrestore(&info->slock, flags);
                }

                mxser_start(tty);
        }
}

/*
 * mxser_wait_until_sent() --- wait until the transmitter is empty
 */
static void mxser_wait_until_sent(struct tty_struct *tty, int timeout)
{
        struct mxser_port *info = tty->driver_data;
        unsigned long orig_jiffies, char_time;
        unsigned long flags;
        int lsr;

        if (info->type == PORT_UNKNOWN)
                return;

        if (info->xmit_fifo_size == 0)
                return;         /* Just in case.... */

        orig_jiffies = jiffies;
        /*
         * Set the check interval to be 1/5 of the estimated time to
         * send a single character, and make it at least 1.  The check
         * interval should also be less than the timeout.
         *
         * Note: we have to use pretty tight timings here to satisfy
         * the NIST-PCTS.
         */
        char_time = (info->timeout - HZ / 50) / info->xmit_fifo_size;
        char_time = char_time / 5;
        if (char_time == 0)
                char_time = 1;
        if (timeout && timeout < char_time)
                char_time = timeout;
        /*
         * If the transmitter hasn't cleared in twice the approximate
         * amount of time to send the entire FIFO, it probably won't

         * ever clear.  This assumes the UART isn't doing flow
         * control, which is currently the case.  Hence, if it ever
         * takes longer than info->timeout, this is probably due to a
         * UART bug of some kind.  So, we clamp the timeout parameter at
         * 2*info->timeout.
         */
        if (!timeout || timeout > 2 * info->timeout)
                timeout = 2 * info->timeout;

        spin_lock_irqsave(&info->slock, flags);
        while (!((lsr = inb(info->ioaddr + UART_LSR)) & UART_LSR_TEMT)) {
                spin_unlock_irqrestore(&info->slock, flags);
                schedule_timeout_interruptible(char_time);
                spin_lock_irqsave(&info->slock, flags);
                if (signal_pending(current))
                        break;
                if (timeout && time_after(jiffies, orig_jiffies + timeout))
                        break;
        }
        spin_unlock_irqrestore(&info->slock, flags);
        set_current_state(TASK_RUNNING);
}

/*
 * This routine is called by tty_hangup() when a hangup is signaled.
 */
static void mxser_hangup(struct tty_struct *tty)
{
        struct mxser_port *info = tty->driver_data;

        mxser_flush_buffer(tty);
        tty_port_hangup(&info->port);
}

/*
 * mxser_rs_break() --- routine which turns the break handling on or off
 */
static int mxser_rs_break(struct tty_struct *tty, int break_state)
{
        struct mxser_port *info = tty->driver_data;
        unsigned long flags;

        spin_lock_irqsave(&info->slock, flags);
        if (break_state == -1)
                outb(inb(info->ioaddr + UART_LCR) | UART_LCR_SBC,
                        info->ioaddr + UART_LCR);
        else
                outb(inb(info->ioaddr + UART_LCR) & ~UART_LCR_SBC,
                        info->ioaddr + UART_LCR);
        spin_unlock_irqrestore(&info->slock, flags);
        return 0;
}

static void mxser_receive_chars(struct tty_struct *tty,
                                struct mxser_port *port, int *status)
{
        unsigned char ch, gdl;
        int ignored = 0;
        int cnt = 0;
        int recv_room;
        int max = 256;

        recv_room = tty->receive_room;
        if (recv_room == 0 && !port->ldisc_stop_rx)
                mxser_stoprx(tty);
        if (port->board->chip_flag != MOXA_OTHER_UART) {

                if (*status & UART_LSR_SPECIAL)
                        goto intr_old;
                if (port->board->chip_flag == MOXA_MUST_MU860_HWID &&
                                (*status & MOXA_MUST_LSR_RERR))
                        goto intr_old;
                if (*status & MOXA_MUST_LSR_RERR)
                        goto intr_old;

                gdl = inb(port->ioaddr + MOXA_MUST_GDL_REGISTER);

                if (port->board->chip_flag == MOXA_MUST_MU150_HWID)
                        gdl &= MOXA_MUST_GDL_MASK;
                if (gdl >= recv_room) {
                        if (!port->ldisc_stop_rx)
                                mxser_stoprx(tty);
                }
                while (gdl--) {
                        ch = inb(port->ioaddr + UART_RX);
                        tty_insert_flip_char(&port->port, ch, 0);
                        cnt++;
                }
                goto end_intr;
        }
intr_old:

        do {
                if (max-- < 0)
                        break;

                ch = inb(port->ioaddr + UART_RX);
                if (port->board->chip_flag && (*status & UART_LSR_OE))
                        outb(0x23, port->ioaddr + UART_FCR);
                *status &= port->read_status_mask;
                if (*status & port->ignore_status_mask) {
                        if (++ignored > 100)
                                break;
                } else {
                        char flag = 0;
                        if (*status & UART_LSR_SPECIAL) {
                                if (*status & UART_LSR_BI) {
                                        flag = TTY_BREAK;
                                        port->icount.brk++;

                                        if (port->port.flags & ASYNC_SAK)
                                                do_SAK(tty);
                                } else if (*status & UART_LSR_PE) {
                                        flag = TTY_PARITY;
                                        port->icount.parity++;
                                } else if (*status & UART_LSR_FE) {
                                        flag = TTY_FRAME;
                                        port->icount.frame++;
                                } else if (*status & UART_LSR_OE) {
                                        flag = TTY_OVERRUN;
                                        port->icount.overrun++;
                                } else
                                        flag = TTY_BREAK;
                        }
                        tty_insert_flip_char(&port->port, ch, flag);
                        cnt++;
                        if (cnt >= recv_room) {
                                if (!port->ldisc_stop_rx)
                                        mxser_stoprx(tty);
                                break;
                        }

                }

                if (port->board->chip_flag)
                        break;

                *status = inb(port->ioaddr + UART_LSR);
        } while (*status & UART_LSR_DR);

end_intr:
        mxvar_log.rxcnt[tty->index] += cnt;
        port->mon_data.rxcnt += cnt;
        port->mon_data.up_rxcnt += cnt;

        /*
         * We are called from an interrupt context with &port->slock
         * being held. Drop it temporarily in order to prevent
         * recursive locking.
         */
        spin_unlock(&port->slock);
        tty_flip_buffer_push(&port->port);
        spin_lock(&port->slock);
}

static void mxser_transmit_chars(struct tty_struct *tty, struct mxser_port *port)
{
        int count, cnt;

        if (port->x_char) {
                outb(port->x_char, port->ioaddr + UART_TX);
                port->x_char = 0;
                mxvar_log.txcnt[tty->index]++;
                port->mon_data.txcnt++;
                port->mon_data.up_txcnt++;
                port->icount.tx++;
                return;
        }

        if (port->port.xmit_buf == NULL)
                return;

        if (port->xmit_cnt <= 0 || tty->stopped ||
                        (tty->hw_stopped &&
                        (port->type != PORT_16550A) &&
                        (!port->board->chip_flag))) {
                port->IER &= ~UART_IER_THRI;
                outb(port->IER, port->ioaddr + UART_IER);
                return;
        }

        cnt = port->xmit_cnt;
        count = port->xmit_fifo_size;
        do {
                outb(port->port.xmit_buf[port->xmit_tail++],
                        port->ioaddr + UART_TX);
                port->xmit_tail = port->xmit_tail & (SERIAL_XMIT_SIZE - 1);
                if (--port->xmit_cnt <= 0)
                        break;
        } while (--count > 0);
        mxvar_log.txcnt[tty->index] += (cnt - port->xmit_cnt);

        port->mon_data.txcnt += (cnt - port->xmit_cnt);
        port->mon_data.up_txcnt += (cnt - port->xmit_cnt);
        port->icount.tx += (cnt - port->xmit_cnt);

        if (port->xmit_cnt < WAKEUP_CHARS)
                tty_wakeup(tty);

        if (port->xmit_cnt <= 0) {
                port->IER &= ~UART_IER_THRI;
                outb(port->IER, port->ioaddr + UART_IER);
        }
}

/*
 * This is the serial driver's generic interrupt routine
 */
static irqreturn_t mxser_interrupt(int irq, void *dev_id)
{
        int status, iir, i;
        struct mxser_board *brd = NULL;
        struct mxser_port *port;
        int max, irqbits, bits, msr;
        unsigned int int_cnt, pass_counter = 0;
        int handled = IRQ_NONE;
        struct tty_struct *tty;

        for (i = 0; i < MXSER_BOARDS; i++)
                if (dev_id == &mxser_boards[i]) {
                        brd = dev_id;
                        break;
                }

        if (i == MXSER_BOARDS)
                goto irq_stop;
        if (brd == NULL)
                goto irq_stop;
        max = brd->info->nports;
        while (pass_counter++ < MXSER_ISR_PASS_LIMIT) {
                irqbits = inb(brd->vector) & brd->vector_mask;
                if (irqbits == brd->vector_mask)
                        break;

                handled = IRQ_HANDLED;
                for (i = 0, bits = 1; i < max; i++, irqbits |= bits, bits <<= 1) {
                        if (irqbits == brd->vector_mask)
                                break;
                        if (bits & irqbits)
                                continue;
                        port = &brd->ports[i];

                        int_cnt = 0;
                        spin_lock(&port->slock);
                        do {
                                iir = inb(port->ioaddr + UART_IIR);
                                if (iir & UART_IIR_NO_INT)
                                        break;
                                iir &= MOXA_MUST_IIR_MASK;
                                tty = tty_port_tty_get(&port->port);
                                if (!tty || port->closing ||
                                    !tty_port_initialized(&port->port)) {
                                        status = inb(port->ioaddr + UART_LSR);
                                        outb(0x27, port->ioaddr + UART_FCR);
                                        inb(port->ioaddr + UART_MSR);
                                        tty_kref_put(tty);
                                        break;
                                }

                                status = inb(port->ioaddr + UART_LSR);

                                if (status & UART_LSR_PE)
                                        port->err_shadow |= NPPI_NOTIFY_PARITY;
                                if (status & UART_LSR_FE)
                                        port->err_shadow |= NPPI_NOTIFY_FRAMING;
                                if (status & UART_LSR_OE)
                                        port->err_shadow |=
                                                NPPI_NOTIFY_HW_OVERRUN;
                                if (status & UART_LSR_BI)
                                        port->err_shadow |= NPPI_NOTIFY_BREAK;

                                if (port->board->chip_flag) {
                                        if (iir == MOXA_MUST_IIR_GDA ||
                                            iir == MOXA_MUST_IIR_RDA ||
                                            iir == MOXA_MUST_IIR_RTO ||
                                            iir == MOXA_MUST_IIR_LSR)
                                                mxser_receive_chars(tty, port,
                                                                &status);

                                } else {
                                        status &= port->read_status_mask;
                                        if (status & UART_LSR_DR)
                                                mxser_receive_chars(tty, port,
                                                                &status);
                                }
                                msr = inb(port->ioaddr + UART_MSR);
                                if (msr & UART_MSR_ANY_DELTA)
                                        mxser_check_modem_status(tty, port, msr);

                                if (port->board->chip_flag) {
                                        if (iir == 0x02 && (status &
                                                                UART_LSR_THRE))
                                                mxser_transmit_chars(tty, port);
                                } else {
                                        if (status & UART_LSR_THRE)
                                                mxser_transmit_chars(tty, port);
                                }
                                tty_kref_put(tty);
                        } while (int_cnt++ < MXSER_ISR_PASS_LIMIT);
                        spin_unlock(&port->slock);
                }
        }

irq_stop:
        return handled;
}

static const struct tty_operations mxser_ops = {
        .open = mxser_open,
        .close = mxser_close,
        .write = mxser_write,
        .put_char = mxser_put_char,
        .flush_chars = mxser_flush_chars,
        .write_room = mxser_write_room,
        .chars_in_buffer = mxser_chars_in_buffer,
        .flush_buffer = mxser_flush_buffer,
        .ioctl = mxser_ioctl,
        .throttle = mxser_throttle,
        .unthrottle = mxser_unthrottle,
        .set_termios = mxser_set_termios,
        .stop = mxser_stop,
        .start = mxser_start,
        .hangup = mxser_hangup,
        .break_ctl = mxser_rs_break,
        .wait_until_sent = mxser_wait_until_sent,
        .tiocmget = mxser_tiocmget,
        .tiocmset = mxser_tiocmset,
        .get_icount = mxser_get_icount,
};

static const struct tty_port_operations mxser_port_ops = {
        .carrier_raised = mxser_carrier_raised,
        .dtr_rts = mxser_dtr_rts,
        .activate = mxser_activate,
        .shutdown = mxser_shutdown_port,
};

/*
 * The MOXA Smartio/Industio serial driver boot-time initialization code!
 */

static bool allow_overlapping_vector;
module_param(allow_overlapping_vector, bool, S_IRUGO);
MODULE_PARM_DESC(allow_overlapping_vector, "whether we allow ISA cards to be configured such that vector overlabs IO ports (default=no)");

static bool mxser_overlapping_vector(struct mxser_board *brd)
{
        return allow_overlapping_vector &&
                brd->vector >= brd->ports[0].ioaddr &&
                brd->vector < brd->ports[0].ioaddr + 8 * brd->info->nports;
}

static int mxser_request_vector(struct mxser_board *brd)
{
        if (mxser_overlapping_vector(brd))
                return 0;
        return request_region(brd->vector, 1, "mxser(vector)") ? 0 : -EIO;
}

static void mxser_release_vector(struct mxser_board *brd)
{
        if (mxser_overlapping_vector(brd))
                return;
        release_region(brd->vector, 1);
}

static void mxser_release_ISA_res(struct mxser_board *brd)
{
        release_region(brd->ports[0].ioaddr, 8 * brd->info->nports);
        mxser_release_vector(brd);
}

static int mxser_initbrd(struct mxser_board *brd)
{
        struct mxser_port *info;
        unsigned int i;
        int retval;

        printk(KERN_INFO "mxser: max. baud rate = %d bps\n",
                        brd->ports[0].max_baud);

        for (i = 0; i < brd->info->nports; i++) {
                info = &brd->ports[i];
                tty_port_init(&info->port);
                info->port.ops = &mxser_port_ops;
                info->board = brd;
                info->stop_rx = 0;
                info->ldisc_stop_rx = 0;

                /* Enhance mode enabled here */
                if (brd->chip_flag != MOXA_OTHER_UART)
                        mxser_enable_must_enchance_mode(info->ioaddr);

                info->type = brd->uart_type;

                process_txrx_fifo(info);

                info->custom_divisor = info->baud_base * 16;
                info->port.close_delay = 5 * HZ / 10;
                info->port.closing_wait = 30 * HZ;
                info->normal_termios = mxvar_sdriver->init_termios;
                memset(&info->mon_data, 0, sizeof(struct mxser_mon));
                info->err_shadow = 0;
                spin_lock_init(&info->slock);

                /* before set INT ISR, disable all int */
                outb(inb(info->ioaddr + UART_IER) & 0xf0,
                        info->ioaddr + UART_IER);
        }

        retval = request_irq(brd->irq, mxser_interrupt, IRQF_SHARED, "mxser",
                        brd);
        if (retval) {
                for (i = 0; i < brd->info->nports; i++)
                        tty_port_destroy(&brd->ports[i].port);
                printk(KERN_ERR "Board %s: Request irq failed, IRQ (%d) may "
                        "conflict with another device.\n",
                        brd->info->name, brd->irq);
        }

        return retval;
}

static void mxser_board_remove(struct mxser_board *brd)
{
        unsigned int i;

        for (i = 0; i < brd->info->nports; i++) {
                tty_unregister_device(mxvar_sdriver, brd->idx + i);
                tty_port_destroy(&brd->ports[i].port);
        }
        free_irq(brd->irq, brd);
}

static int __init mxser_get_ISA_conf(int cap, struct mxser_board *brd)
{
        int id, i, bits, ret;
        unsigned short regs[16], irq;
        unsigned char scratch, scratch2;

        brd->chip_flag = MOXA_OTHER_UART;

        id = mxser_read_register(cap, regs);
        switch (id) {
        case C168_ASIC_ID:
                brd->info = &mxser_cards[0];
                break;
        case C104_ASIC_ID:
                brd->info = &mxser_cards[1];
                break;
        case CI104J_ASIC_ID:
                brd->info = &mxser_cards[2];
                break;
        case C102_ASIC_ID:
                brd->info = &mxser_cards[5];
                break;
        case CI132_ASIC_ID:
                brd->info = &mxser_cards[6];
                break;
        case CI134_ASIC_ID:
                brd->info = &mxser_cards[7];
                break;
        default:
                return 0;
        }

        irq = 0;
        /* some ISA cards have 2 ports, but we want to see them as 4-port (why?)
           Flag-hack checks if configuration should be read as 2-port here. */
        if (brd->info->nports == 2 || (brd->info->flags & MXSER_HAS2)) {
                irq = regs[9] & 0xF000;
                irq = irq | (irq >> 4);
                if (irq != (regs[9] & 0xFF00))
                        goto err_irqconflict;
        } else if (brd->info->nports == 4) {
                irq = regs[9] & 0xF000;
                irq = irq | (irq >> 4);
                irq = irq | (irq >> 8);
                if (irq != regs[9])
                        goto err_irqconflict;
        } else if (brd->info->nports == 8) {
                irq = regs[9] & 0xF000;
                irq = irq | (irq >> 4);
                irq = irq | (irq >> 8);
                if ((irq != regs[9]) || (irq != regs[10]))
                        goto err_irqconflict;
        }

        if (!irq) {
                printk(KERN_ERR "mxser: interrupt number unset\n");
                return -EIO;
        }
        brd->irq = ((int)(irq & 0xF000) >> 12);
        for (i = 0; i < 8; i++)
                brd->ports[i].ioaddr = (int) regs[i + 1] & 0xFFF8;
        if ((regs[12] & 0x80) == 0) {
                printk(KERN_ERR "mxser: invalid interrupt vector\n");
                return -EIO;
        }
        brd->vector = (int)regs[11];    /* interrupt vector */
        if (id == 1)
                brd->vector_mask = 0x00FF;
        else
                brd->vector_mask = 0x000F;
        for (i = 7, bits = 0x0100; i >= 0; i--, bits <<= 1) {
                if (regs[12] & bits) {
                        brd->ports[i].baud_base = 921600;
                        brd->ports[i].max_baud = 921600;
                } else {
                        brd->ports[i].baud_base = 115200;
                        brd->ports[i].max_baud = 115200;
                }
        }
        scratch2 = inb(cap + UART_LCR) & (~UART_LCR_DLAB);
        outb(scratch2 | UART_LCR_DLAB, cap + UART_LCR);
        outb(0, cap + UART_EFR);        /* EFR is the same as FCR */
        outb(scratch2, cap + UART_LCR);
        outb(UART_FCR_ENABLE_FIFO, cap + UART_FCR);
        scratch = inb(cap + UART_IIR);

        if (scratch & 0xC0)
                brd->uart_type = PORT_16550A;
        else
                brd->uart_type = PORT_16450;
        if (!request_region(brd->ports[0].ioaddr, 8 * brd->info->nports,
                        "mxser(IO)")) {
                printk(KERN_ERR "mxser: can't request ports I/O region: "
                                "0x%.8lx-0x%.8lx\n",
                                brd->ports[0].ioaddr, brd->ports[0].ioaddr +
                                8 * brd->info->nports - 1);
                return -EIO;
        }

        ret = mxser_request_vector(brd);
        if (ret) {
                release_region(brd->ports[0].ioaddr, 8 * brd->info->nports);
                printk(KERN_ERR "mxser: can't request interrupt vector region: "
                                "0x%.8lx-0x%.8lx\n",
                                brd->ports[0].ioaddr, brd->ports[0].ioaddr +
                                8 * brd->info->nports - 1);
                return ret;
        }
        return brd->info->nports;

err_irqconflict:
        printk(KERN_ERR "mxser: invalid interrupt number\n");
        return -EIO;
}

static int mxser_probe(struct pci_dev *pdev,
                const struct pci_device_id *ent)
{
#ifdef CONFIG_PCI
        struct mxser_board *brd;
        unsigned int i, j;
        unsigned long ioaddress;
        struct device *tty_dev;
        int retval = -EINVAL;

        for (i = 0; i < MXSER_BOARDS; i++)
                if (mxser_boards[i].info == NULL)
                        break;

        if (i >= MXSER_BOARDS) {
                dev_err(&pdev->dev, "too many boards found (maximum %d), board "
                                "not configured\n", MXSER_BOARDS);
                goto err;
        }

        brd = &mxser_boards[i];
        brd->idx = i * MXSER_PORTS_PER_BOARD;
        dev_info(&pdev->dev, "found MOXA %s board (BusNo=%d, DevNo=%d)\n",
                mxser_cards[ent->driver_data].name,
                pdev->bus->number, PCI_SLOT(pdev->devfn));

        retval = pci_enable_device(pdev);
        if (retval) {
                dev_err(&pdev->dev, "PCI enable failed\n");
                goto err;
        }

        /* io address */
        ioaddress = pci_resource_start(pdev, 2);
        retval = pci_request_region(pdev, 2, "mxser(IO)");
        if (retval)
                goto err_dis;

        brd->info = &mxser_cards[ent->driver_data];
        for (i = 0; i < brd->info->nports; i++)
                brd->ports[i].ioaddr = ioaddress + 8 * i;

        /* vector */
        ioaddress = pci_resource_start(pdev, 3);
        retval = pci_request_region(pdev, 3, "mxser(vector)");
        if (retval)
                goto err_zero;
        brd->vector = ioaddress;

        /* irq */
        brd->irq = pdev->irq;

        brd->chip_flag = CheckIsMoxaMust(brd->ports[0].ioaddr);
        brd->uart_type = PORT_16550A;
        brd->vector_mask = 0;

        for (i = 0; i < brd->info->nports; i++) {
                for (j = 0; j < UART_INFO_NUM; j++) {
                        if (Gpci_uart_info[j].type == brd->chip_flag) {
                                brd->ports[i].max_baud =
                                        Gpci_uart_info[j].max_baud;

                                /* exception....CP-102 */
                                if (brd->info->flags & MXSER_HIGHBAUD)
                                        brd->ports[i].max_baud = 921600;
                                break;
                        }
                }
        }

        if (brd->chip_flag == MOXA_MUST_MU860_HWID) {
                for (i = 0; i < brd->info->nports; i++) {
                        if (i < 4)
                                brd->ports[i].opmode_ioaddr = ioaddress + 4;
                        else
                                brd->ports[i].opmode_ioaddr = ioaddress + 0x0c;
                }
                outb(0, ioaddress + 4); /* default set to RS232 mode */
                outb(0, ioaddress + 0x0c);      /* default set to RS232 mode */
        }

        for (i = 0; i < brd->info->nports; i++) {
                brd->vector_mask |= (1 << i);
                brd->ports[i].baud_base = 921600;
        }

        /* mxser_initbrd will hook ISR. */
        retval = mxser_initbrd(brd);
        if (retval)
                goto err_rel3;

        for (i = 0; i < brd->info->nports; i++) {
                tty_dev = tty_port_register_device(&brd->ports[i].port,
                                mxvar_sdriver, brd->idx + i, &pdev->dev);
                if (IS_ERR(tty_dev)) {
                        retval = PTR_ERR(tty_dev);
                        for (; i > 0; i--)
                                tty_unregister_device(mxvar_sdriver,
                                        brd->idx + i - 1);
                        goto err_relbrd;
                }
        }

        pci_set_drvdata(pdev, brd);

        return 0;
err_relbrd:
        for (i = 0; i < brd->info->nports; i++)
                tty_port_destroy(&brd->ports[i].port);
        free_irq(brd->irq, brd);
err_rel3:
        pci_release_region(pdev, 3);
err_zero:
        brd->info = NULL;
        pci_release_region(pdev, 2);
err_dis:
        pci_disable_device(pdev);
err:
        return retval;
#else
        return -ENODEV;
#endif
}

static void mxser_remove(struct pci_dev *pdev)
{
#ifdef CONFIG_PCI
        struct mxser_board *brd = pci_get_drvdata(pdev);

        mxser_board_remove(brd);

        pci_release_region(pdev, 2);
        pci_release_region(pdev, 3);
        pci_disable_device(pdev);
        brd->info = NULL;
#endif
}

static struct pci_driver mxser_driver = {
        .name = "mxser",
        .id_table = mxser_pcibrds,
        .probe = mxser_probe,
        .remove = mxser_remove
};

static int __init mxser_module_init(void)
{
        struct mxser_board *brd;
        struct device *tty_dev;
        unsigned int b, i, m;
        int retval;

        mxvar_sdriver = alloc_tty_driver(MXSER_PORTS + 1);
        if (!mxvar_sdriver)
                return -ENOMEM;

        printk(KERN_INFO "MOXA Smartio/Industio family driver version %s\n",
                MXSER_VERSION);

        /* Initialize the tty_driver structure */
        mxvar_sdriver->name = "ttyMI";
        mxvar_sdriver->major = ttymajor;
        mxvar_sdriver->minor_start = 0;
        mxvar_sdriver->type = TTY_DRIVER_TYPE_SERIAL;
        mxvar_sdriver->subtype = SERIAL_TYPE_NORMAL;
        mxvar_sdriver->init_termios = tty_std_termios;
        mxvar_sdriver->init_termios.c_cflag = B9600|CS8|CREAD|HUPCL|CLOCAL;
        mxvar_sdriver->flags = TTY_DRIVER_REAL_RAW|TTY_DRIVER_DYNAMIC_DEV;
        tty_set_operations(mxvar_sdriver, &mxser_ops);

        retval = tty_register_driver(mxvar_sdriver);
        if (retval) {
                printk(KERN_ERR "Couldn't install MOXA Smartio/Industio family "
                                "tty driver !\n");
                goto err_put;
        }

        /* Start finding ISA boards here */
        for (m = 0, b = 0; b < MXSER_BOARDS; b++) {
                if (!ioaddr[b])
                        continue;

                brd = &mxser_boards[m];
                retval = mxser_get_ISA_conf(ioaddr[b], brd);
                if (retval <= 0) {
                        brd->info = NULL;
                        continue;
                }

                printk(KERN_INFO "mxser: found MOXA %s board (CAP=0x%lx)\n",
                                brd->info->name, ioaddr[b]);

                /* mxser_initbrd will hook ISR. */
                if (mxser_initbrd(brd) < 0) {
                        mxser_release_ISA_res(brd);
                        brd->info = NULL;
                        continue;
                }

                brd->idx = m * MXSER_PORTS_PER_BOARD;
                for (i = 0; i < brd->info->nports; i++) {
                        tty_dev = tty_port_register_device(&brd->ports[i].port,
                                        mxvar_sdriver, brd->idx + i, NULL);
                        if (IS_ERR(tty_dev)) {
                                for (; i > 0; i--)
                                        tty_unregister_device(mxvar_sdriver,
                                                brd->idx + i - 1);
                                for (i = 0; i < brd->info->nports; i++)
                                        tty_port_destroy(&brd->ports[i].port);
                                free_irq(brd->irq, brd);
                                mxser_release_ISA_res(brd);
                                brd->info = NULL;
                                break;
                        }
                }
                if (brd->info == NULL)
                        continue;

                m++;
        }

        retval = pci_register_driver(&mxser_driver);
        if (retval) {
                printk(KERN_ERR "mxser: can't register pci driver\n");
                if (!m) {
                        retval = -ENODEV;
                        goto err_unr;
                } /* else: we have some ISA cards under control */
        }

        return 0;
err_unr:
        tty_unregister_driver(mxvar_sdriver);
err_put:
        put_tty_driver(mxvar_sdriver);
        return retval;
}

static void __exit mxser_module_exit(void)
{
        unsigned int i;

        pci_unregister_driver(&mxser_driver);

        for (i = 0; i < MXSER_BOARDS; i++) /* ISA remains */
                if (mxser_boards[i].info != NULL)
                        mxser_board_remove(&mxser_boards[i]);
        tty_unregister_driver(mxvar_sdriver);
        put_tty_driver(mxvar_sdriver);

        for (i = 0; i < MXSER_BOARDS; i++)
                if (mxser_boards[i].info != NULL)
                        mxser_release_ISA_res(&mxser_boards[i]);
}

module_init(mxser_module_init);
module_exit(mxser_module_exit);