/*
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
 *
 * Clean ups from Moschip version and a few ioctl implementations by:
 *      Paul B Schroeder <pschroeder "at" uplogix "dot" com>
 *
 * Originally based on drivers/usb/serial/io_edgeport.c which is:
 *      Copyright (C) 2000 Inside Out Networks, All rights reserved.
 *      Copyright (C) 2001-2002 Greg Kroah-Hartman <greg@kroah.com>
 *
 */

#include <linux/kernel.h>
#include <linux/errno.h>
#include <linux/init.h>
#include <linux/slab.h>
#include <linux/smp_lock.h>
#include <linux/tty.h>
#include <linux/tty_driver.h>
#include <linux/tty_flip.h>
#include <linux/module.h>
#include <linux/serial.h>
#include <linux/usb.h>
#include <linux/usb/serial.h>
#include <linux/uaccess.h>

/*
 * Version Information
 */
#define DRIVER_VERSION "1.3.2"
#define DRIVER_DESC "Moschip 7840/7820 USB Serial Driver"

/*
 * 16C50 UART register defines
 */

#define LCR_BITS_5             0x00     /* 5 bits/char */
#define LCR_BITS_6             0x01     /* 6 bits/char */
#define LCR_BITS_7             0x02     /* 7 bits/char */
#define LCR_BITS_8             0x03     /* 8 bits/char */
#define LCR_BITS_MASK          0x03     /* Mask for bits/char field */

#define LCR_STOP_1             0x00     /* 1 stop bit */
#define LCR_STOP_1_5           0x04     /* 1.5 stop bits (if 5   bits/char) */
#define LCR_STOP_2             0x04     /* 2 stop bits   (if 6-8 bits/char) */
#define LCR_STOP_MASK          0x04     /* Mask for stop bits field */

#define LCR_PAR_NONE           0x00     /* No parity */
#define LCR_PAR_ODD            0x08     /* Odd parity */
#define LCR_PAR_EVEN           0x18     /* Even parity */
#define LCR_PAR_MARK           0x28     /* Force parity bit to 1 */
#define LCR_PAR_SPACE          0x38     /* Force parity bit to 0 */
#define LCR_PAR_MASK           0x38     /* Mask for parity field */

#define LCR_SET_BREAK          0x40     /* Set Break condition */
#define LCR_DL_ENABLE          0x80     /* Enable access to divisor latch */

#define MCR_DTR                0x01     /* Assert DTR */
#define MCR_RTS                0x02     /* Assert RTS */
#define MCR_OUT1               0x04     /* Loopback only: Sets state of RI */
#define MCR_MASTER_IE          0x08     /* Enable interrupt outputs */
#define MCR_LOOPBACK           0x10     /* Set internal (digital) loopback mode */
#define MCR_XON_ANY            0x20     /* Enable any char to exit XOFF mode */

#define MOS7840_MSR_CTS        0x10     /* Current state of CTS */
#define MOS7840_MSR_DSR        0x20     /* Current state of DSR */
#define MOS7840_MSR_RI         0x40     /* Current state of RI */
#define MOS7840_MSR_CD         0x80     /* Current state of CD */

/*
 * Defines used for sending commands to port
 */

#define WAIT_FOR_EVER   (HZ * 0)        /* timeout urb is wait for ever */
#define MOS_WDR_TIMEOUT (HZ * 5)        /* default urb timeout */

#define MOS_PORT1       0x0200
#define MOS_PORT2       0x0300
#define MOS_VENREG      0x0000
#define MOS_MAX_PORT    0x02
#define MOS_WRITE       0x0E
#define MOS_READ        0x0D

/* Requests */
#define MCS_RD_RTYPE    0xC0
#define MCS_WR_RTYPE    0x40
#define MCS_RDREQ       0x0D
#define MCS_WRREQ       0x0E
#define MCS_CTRL_TIMEOUT        500
#define VENDOR_READ_LENGTH      (0x01)

#define MAX_NAME_LEN    64

#define ZLP_REG1  0x3A          /* Zero_Flag_Reg1    58 */
#define ZLP_REG5  0x3E          /* Zero_Flag_Reg5    62 */

/* For higher baud Rates use TIOCEXBAUD */
#define TIOCEXBAUD     0x5462

/* vendor id and device id defines */

/* The native mos7840/7820 component */
#define USB_VENDOR_ID_MOSCHIP           0x9710
#define MOSCHIP_DEVICE_ID_7840          0x7840
#define MOSCHIP_DEVICE_ID_7820          0x7820
/* The native component can have its vendor/device id's overridden
 * in vendor-specific implementations.  Such devices can be handled
 * by making a change here, in moschip_port_id_table, and in
 * moschip_id_table_combined
 */
#define USB_VENDOR_ID_BANDB             0x0856
#define BANDB_DEVICE_ID_USOPTL4_4       0xAC44
#define BANDB_DEVICE_ID_USOPTL4_2       0xAC42

/* This driver also supports
 * ATEN UC2324 device using Moschip MCS7840
 * ATEN UC2322 device using Moschip MCS7820
 */
#define USB_VENDOR_ID_ATENINTL          0x0557
#define ATENINTL_DEVICE_ID_UC2324       0x2011
#define ATENINTL_DEVICE_ID_UC2322       0x7820

/* Interrupt Routine Defines    */

#define SERIAL_IIR_RLS      0x06
#define SERIAL_IIR_MS       0x00

/*
 *  Emulation of the bit mask on the LINE STATUS REGISTER.
 */
#define SERIAL_LSR_DR       0x0001
#define SERIAL_LSR_OE       0x0002
#define SERIAL_LSR_PE       0x0004
#define SERIAL_LSR_FE       0x0008
#define SERIAL_LSR_BI       0x0010

#define MOS_MSR_DELTA_CTS   0x10
#define MOS_MSR_DELTA_DSR   0x20
#define MOS_MSR_DELTA_RI    0x40
#define MOS_MSR_DELTA_CD    0x80

/* Serial Port register Address */
#define INTERRUPT_ENABLE_REGISTER  ((__u16)(0x01))
#define FIFO_CONTROL_REGISTER      ((__u16)(0x02))
#define LINE_CONTROL_REGISTER      ((__u16)(0x03))
#define MODEM_CONTROL_REGISTER     ((__u16)(0x04))
#define LINE_STATUS_REGISTER       ((__u16)(0x05))
#define MODEM_STATUS_REGISTER      ((__u16)(0x06))
#define SCRATCH_PAD_REGISTER       ((__u16)(0x07))
#define DIVISOR_LATCH_LSB          ((__u16)(0x00))
#define DIVISOR_LATCH_MSB          ((__u16)(0x01))

#define CLK_MULTI_REGISTER         ((__u16)(0x02))
#define CLK_START_VALUE_REGISTER   ((__u16)(0x03))

#define SERIAL_LCR_DLAB            ((__u16)(0x0080))

/*
 * URB POOL related defines
 */
#define NUM_URBS                        16      /* URB Count */
#define URB_TRANSFER_BUFFER_SIZE        32      /* URB Size  */


static struct usb_device_id moschip_port_id_table[] = {
        {USB_DEVICE(USB_VENDOR_ID_MOSCHIP, MOSCHIP_DEVICE_ID_7840)},
        {USB_DEVICE(USB_VENDOR_ID_MOSCHIP, MOSCHIP_DEVICE_ID_7820)},
        {USB_DEVICE(USB_VENDOR_ID_BANDB, BANDB_DEVICE_ID_USOPTL4_4)},
        {USB_DEVICE(USB_VENDOR_ID_BANDB, BANDB_DEVICE_ID_USOPTL4_2)},
        {USB_DEVICE(USB_VENDOR_ID_ATENINTL, ATENINTL_DEVICE_ID_UC2324)},
        {USB_DEVICE(USB_VENDOR_ID_ATENINTL, ATENINTL_DEVICE_ID_UC2322)},
        {}                      /* terminating entry */
};

static __devinitdata struct usb_device_id moschip_id_table_combined[] = {
        {USB_DEVICE(USB_VENDOR_ID_MOSCHIP, MOSCHIP_DEVICE_ID_7840)},
        {USB_DEVICE(USB_VENDOR_ID_MOSCHIP, MOSCHIP_DEVICE_ID_7820)},
        {USB_DEVICE(USB_VENDOR_ID_BANDB, BANDB_DEVICE_ID_USOPTL4_4)},
        {USB_DEVICE(USB_VENDOR_ID_BANDB, BANDB_DEVICE_ID_USOPTL4_2)},
        {USB_DEVICE(USB_VENDOR_ID_ATENINTL, ATENINTL_DEVICE_ID_UC2324)},
        {USB_DEVICE(USB_VENDOR_ID_ATENINTL, ATENINTL_DEVICE_ID_UC2322)},
        {}                      /* terminating entry */
};

MODULE_DEVICE_TABLE(usb, moschip_id_table_combined);

/* This structure holds all of the local port information */

struct moschip_port {
        int port_num;           /*Actual port number in the device(1,2,etc) */
        struct urb *write_urb;  /* write URB for this port */
        struct urb *read_urb;   /* read URB for this port */
        struct urb *int_urb;
        __u8 shadowLCR;         /* last LCR value received */
        __u8 shadowMCR;         /* last MCR value received */
        char open;
        char open_ports;
        char zombie;
        wait_queue_head_t wait_chase;   /* for handling sleeping while waiting for chase to finish */
        wait_queue_head_t delta_msr_wait;       /* for handling sleeping while waiting for msr change to happen */
        int delta_msr_cond;
        struct async_icount icount;
        struct usb_serial_port *port;   /* loop back to the owner of this object */

        /* Offsets */
        __u8 SpRegOffset;
        __u8 ControlRegOffset;
        __u8 DcrRegOffset;
        /* for processing control URBS in interrupt context */
        struct urb *control_urb;
        struct usb_ctrlrequest *dr;
        char *ctrl_buf;
        int MsrLsr;

        spinlock_t pool_lock;
        struct urb *write_urb_pool[NUM_URBS];
        char busy[NUM_URBS];
        bool read_urb_busy;
};


static int debug;

/*
 * mos7840_set_reg_sync
 *      To set the Control register by calling usb_fill_control_urb function
 *      by passing usb_sndctrlpipe function as parameter.
 */

static int mos7840_set_reg_sync(struct usb_serial_port *port, __u16 reg,
                                __u16 val)
{
        struct usb_device *dev = port->serial->dev;
        val = val & 0x00ff;
        dbg("mos7840_set_reg_sync offset is %x, value %x", reg, val);

        return usb_control_msg(dev, usb_sndctrlpipe(dev, 0), MCS_WRREQ,
                               MCS_WR_RTYPE, val, reg, NULL, 0,
                               MOS_WDR_TIMEOUT);
}

/*
 * mos7840_get_reg_sync
 *      To set the Uart register by calling usb_fill_control_urb function by
 *      passing usb_rcvctrlpipe function as parameter.
 */

static int mos7840_get_reg_sync(struct usb_serial_port *port, __u16 reg,
                                __u16 *val)
{
        struct usb_device *dev = port->serial->dev;
        int ret = 0;

        ret = usb_control_msg(dev, usb_rcvctrlpipe(dev, 0), MCS_RDREQ,
                              MCS_RD_RTYPE, 0, reg, val, VENDOR_READ_LENGTH,
                              MOS_WDR_TIMEOUT);
        dbg("mos7840_get_reg_sync offset is %x, return val %x", reg, *val);
        *val = (*val) & 0x00ff;
        return ret;
}

/*
 * mos7840_set_uart_reg
 *      To set the Uart register by calling usb_fill_control_urb function by
 *      passing usb_sndctrlpipe function as parameter.
 */

static int mos7840_set_uart_reg(struct usb_serial_port *port, __u16 reg,
                                __u16 val)
{

        struct usb_device *dev = port->serial->dev;
        val = val & 0x00ff;
        /* For the UART control registers, the application number need
           to be Or'ed */
        if (port->serial->num_ports == 4) {
                val |= (((__u16) port->number -
                                (__u16) (port->serial->minor)) + 1) << 8;
                dbg("mos7840_set_uart_reg application number is %x", val);
        } else {
                if (((__u16) port->number - (__u16) (port->serial->minor)) == 0) {
                        val |= (((__u16) port->number -
                              (__u16) (port->serial->minor)) + 1) << 8;
                        dbg("mos7840_set_uart_reg application number is %x",
                            val);
                } else {
                        val |=
                            (((__u16) port->number -
                              (__u16) (port->serial->minor)) + 2) << 8;
                        dbg("mos7840_set_uart_reg application number is %x",
                            val);
                }
        }
        return usb_control_msg(dev, usb_sndctrlpipe(dev, 0), MCS_WRREQ,
                               MCS_WR_RTYPE, val, reg, NULL, 0,
                               MOS_WDR_TIMEOUT);

}

/*
 * mos7840_get_uart_reg
 *      To set the Control register by calling usb_fill_control_urb function
 *      by passing usb_rcvctrlpipe function as parameter.
 */
static int mos7840_get_uart_reg(struct usb_serial_port *port, __u16 reg,
                                __u16 *val)
{
        struct usb_device *dev = port->serial->dev;
        int ret = 0;
        __u16 Wval;

        /* dbg("application number is %4x",
            (((__u16)port->number - (__u16)(port->serial->minor))+1)<<8); */
        /* Wval  is same as application number */
        if (port->serial->num_ports == 4) {
                Wval =
                    (((__u16) port->number - (__u16) (port->serial->minor)) +
                     1) << 8;
                dbg("mos7840_get_uart_reg application number is %x", Wval);
        } else {
                if (((__u16) port->number - (__u16) (port->serial->minor)) == 0) {
                        Wval = (((__u16) port->number -
                              (__u16) (port->serial->minor)) + 1) << 8;
                        dbg("mos7840_get_uart_reg application number is %x",
                            Wval);
                } else {
                        Wval = (((__u16) port->number -
                              (__u16) (port->serial->minor)) + 2) << 8;
                        dbg("mos7840_get_uart_reg application number is %x",
                            Wval);
                }
        }
        ret = usb_control_msg(dev, usb_rcvctrlpipe(dev, 0), MCS_RDREQ,
                              MCS_RD_RTYPE, Wval, reg, val, VENDOR_READ_LENGTH,
                              MOS_WDR_TIMEOUT);
        *val = (*val) & 0x00ff;
        return ret;
}

static void mos7840_dump_serial_port(struct moschip_port *mos7840_port)
{

        dbg("***************************************");
        dbg("SpRegOffset is %2x", mos7840_port->SpRegOffset);
        dbg("ControlRegOffset is %2x", mos7840_port->ControlRegOffset);
        dbg("DCRRegOffset is %2x", mos7840_port->DcrRegOffset);
        dbg("***************************************");

}

/************************************************************************/
/************************************************************************/
/*             I N T E R F A C E   F U N C T I O N S                    */
/*             I N T E R F A C E   F U N C T I O N S                    */
/************************************************************************/
/************************************************************************/

static inline void mos7840_set_port_private(struct usb_serial_port *port,
                                            struct moschip_port *data)
{
        usb_set_serial_port_data(port, (void *)data);
}

static inline struct moschip_port *mos7840_get_port_private(struct
                                                            usb_serial_port
                                                            *port)
{
        return (struct moschip_port *)usb_get_serial_port_data(port);
}

static void mos7840_handle_new_msr(struct moschip_port *port, __u8 new_msr)
{
        struct moschip_port *mos7840_port;
        struct async_icount *icount;
        mos7840_port = port;
        icount = &mos7840_port->icount;
        if (new_msr &
            (MOS_MSR_DELTA_CTS | MOS_MSR_DELTA_DSR | MOS_MSR_DELTA_RI |
             MOS_MSR_DELTA_CD)) {
                icount = &mos7840_port->icount;

                /* update input line counters */
                if (new_msr & MOS_MSR_DELTA_CTS) {
                        icount->cts++;
                        smp_wmb();
                }
                if (new_msr & MOS_MSR_DELTA_DSR) {
                        icount->dsr++;
                        smp_wmb();
                }
                if (new_msr & MOS_MSR_DELTA_CD) {
                        icount->dcd++;
                        smp_wmb();
                }
                if (new_msr & MOS_MSR_DELTA_RI) {
                        icount->rng++;
                        smp_wmb();
                }
        }
}

static void mos7840_handle_new_lsr(struct moschip_port *port, __u8 new_lsr)
{
        struct async_icount *icount;

        dbg("%s - %02x", __func__, new_lsr);

        if (new_lsr & SERIAL_LSR_BI) {
                /*
                 * Parity and Framing errors only count if they
                 * occur exclusive of a break being
                 * received.
                 */
                new_lsr &= (__u8) (SERIAL_LSR_OE | SERIAL_LSR_BI);
        }

        /* update input line counters */
        icount = &port->icount;
        if (new_lsr & SERIAL_LSR_BI) {
                icount->brk++;
                smp_wmb();
        }
        if (new_lsr & SERIAL_LSR_OE) {
                icount->overrun++;
                smp_wmb();
        }
        if (new_lsr & SERIAL_LSR_PE) {
                icount->parity++;
                smp_wmb();
        }
        if (new_lsr & SERIAL_LSR_FE) {
                icount->frame++;
                smp_wmb();
        }
}

/************************************************************************/
/************************************************************************/
/*            U S B  C A L L B A C K   F U N C T I O N S                */
/*            U S B  C A L L B A C K   F U N C T I O N S                */
/************************************************************************/
/************************************************************************/

static void mos7840_control_callback(struct urb *urb)
{
        unsigned char *data;
        struct moschip_port *mos7840_port;
        __u8 regval = 0x0;
        int result = 0;
        int status = urb->status;

        mos7840_port = urb->context;

        switch (status) {
        case 0:
                /* success */
                break;
        case -ECONNRESET:
        case -ENOENT:
        case -ESHUTDOWN:
                /* this urb is terminated, clean up */
                dbg("%s - urb shutting down with status: %d", __func__,
                    status);
                return;
        default:
                dbg("%s - nonzero urb status received: %d", __func__,
                    status);
                goto exit;
        }

        dbg("%s urb buffer size is %d", __func__, urb->actual_length);
        dbg("%s mos7840_port->MsrLsr is %d port %d", __func__,
            mos7840_port->MsrLsr, mos7840_port->port_num);
        data = urb->transfer_buffer;
        regval = (__u8) data[0];
        dbg("%s data is %x", __func__, regval);
        if (mos7840_port->MsrLsr == 0)
                mos7840_handle_new_msr(mos7840_port, regval);
        else if (mos7840_port->MsrLsr == 1)
                mos7840_handle_new_lsr(mos7840_port, regval);

exit:
        spin_lock(&mos7840_port->pool_lock);
        if (!mos7840_port->zombie)
                result = usb_submit_urb(mos7840_port->int_urb, GFP_ATOMIC);
        spin_unlock(&mos7840_port->pool_lock);
        if (result) {
                dev_err(&urb->dev->dev,
                        "%s - Error %d submitting interrupt urb\n",
                        __func__, result);
        }
}

static int mos7840_get_reg(struct moschip_port *mcs, __u16 Wval, __u16 reg,
                           __u16 *val)
{
        struct usb_device *dev = mcs->port->serial->dev;
        struct usb_ctrlrequest *dr = mcs->dr;
        unsigned char *buffer = mcs->ctrl_buf;
        int ret;

        dr->bRequestType = MCS_RD_RTYPE;
        dr->bRequest = MCS_RDREQ;
        dr->wValue = cpu_to_le16(Wval); /* 0 */
        dr->wIndex = cpu_to_le16(reg);
        dr->wLength = cpu_to_le16(2);

        usb_fill_control_urb(mcs->control_urb, dev, usb_rcvctrlpipe(dev, 0),
                             (unsigned char *)dr, buffer, 2,
                             mos7840_control_callback, mcs);
        mcs->control_urb->transfer_buffer_length = 2;
        ret = usb_submit_urb(mcs->control_urb, GFP_ATOMIC);
        return ret;
}

/*****************************************************************************
 * mos7840_interrupt_callback
 *      this is the callback function for when we have received data on the
 *      interrupt endpoint.
 *****************************************************************************/

static void mos7840_interrupt_callback(struct urb *urb)
{
        int result;
        int length;
        struct moschip_port *mos7840_port;
        struct usb_serial *serial;
        __u16 Data;
        unsigned char *data;
        __u8 sp[5], st;
        int i, rv = 0;
        __u16 wval, wreg = 0;
        int status = urb->status;

        dbg("%s", " : Entering");

        switch (status) {
        case 0:
                /* success */
                break;
        case -ECONNRESET:
        case -ENOENT:
        case -ESHUTDOWN:
                /* this urb is terminated, clean up */
                dbg("%s - urb shutting down with status: %d", __func__,
                    status);
                return;
        default:
                dbg("%s - nonzero urb status received: %d", __func__,
                    status);
                goto exit;
        }

        length = urb->actual_length;
        data = urb->transfer_buffer;

        serial = urb->context;

        /* Moschip get 5 bytes
         * Byte 1 IIR Port 1 (port.number is 0)
         * Byte 2 IIR Port 2 (port.number is 1)
         * Byte 3 IIR Port 3 (port.number is 2)
         * Byte 4 IIR Port 4 (port.number is 3)
         * Byte 5 FIFO status for both */

        if (length && length > 5) {
                dbg("%s", "Wrong data !!!");
                return;
        }

        sp[0] = (__u8) data[0];
        sp[1] = (__u8) data[1];
        sp[2] = (__u8) data[2];
        sp[3] = (__u8) data[3];
        st = (__u8) data[4];

        for (i = 0; i < serial->num_ports; i++) {
                mos7840_port = mos7840_get_port_private(serial->port[i]);
                wval =
                    (((__u16) serial->port[i]->number -
                      (__u16) (serial->minor)) + 1) << 8;
                if (mos7840_port->open) {
                        if (sp[i] & 0x01) {
                                dbg("SP%d No Interrupt !!!", i);
                        } else {
                                switch (sp[i] & 0x0f) {
                                case SERIAL_IIR_RLS:
                                        dbg("Serial Port %d: Receiver status error or ", i);
                                        dbg("address bit detected in 9-bit mode");
                                        mos7840_port->MsrLsr = 1;
                                        wreg = LINE_STATUS_REGISTER;
                                        break;
                                case SERIAL_IIR_MS:
                                        dbg("Serial Port %d: Modem status change", i);
                                        mos7840_port->MsrLsr = 0;
                                        wreg = MODEM_STATUS_REGISTER;
                                        break;
                                }
                                spin_lock(&mos7840_port->pool_lock);
                                if (!mos7840_port->zombie) {
                                        rv = mos7840_get_reg(mos7840_port, wval, wreg, &Data);
                                } else {
                                        spin_unlock(&mos7840_port->pool_lock);
                                        return;
                                }
                                spin_unlock(&mos7840_port->pool_lock);
                        }
                }
        }
        if (!(rv < 0))
                /* the completion handler for the control urb will resubmit */
                return;
exit:
        result = usb_submit_urb(urb, GFP_ATOMIC);
        if (result) {
                dev_err(&urb->dev->dev,
                        "%s - Error %d submitting interrupt urb\n",
                        __func__, result);
        }
}

static int mos7840_port_paranoia_check(struct usb_serial_port *port,
                                       const char *function)
{
        if (!port) {
                dbg("%s - port == NULL", function);
                return -1;
        }
        if (!port->serial) {
                dbg("%s - port->serial == NULL", function);
                return -1;
        }

        return 0;
}

/* Inline functions to check the sanity of a pointer that is passed to us */
static int mos7840_serial_paranoia_check(struct usb_serial *serial,
                                         const char *function)
{
        if (!serial) {
                dbg("%s - serial == NULL", function);
                return -1;
        }
        if (!serial->type) {
                dbg("%s - serial->type == NULL!", function);
                return -1;
        }

        return 0;
}

static struct usb_serial *mos7840_get_usb_serial(struct usb_serial_port *port,
                                                 const char *function)
{
        /* if no port was specified, or it fails a paranoia check */
        if (!port ||
            mos7840_port_paranoia_check(port, function) ||
            mos7840_serial_paranoia_check(port->serial, function)) {
                /* then say that we don't have a valid usb_serial thing,
                 * which will end up genrating -ENODEV return values */
                return NULL;
        }

        return port->serial;
}

/*****************************************************************************
 * mos7840_bulk_in_callback
 *      this is the callback function for when we have received data on the
 *      bulk in endpoint.
 *****************************************************************************/

static void mos7840_bulk_in_callback(struct urb *urb)
{
        int retval;
        unsigned char *data;
        struct usb_serial *serial;
        struct usb_serial_port *port;
        struct moschip_port *mos7840_port;
        struct tty_struct *tty;
        int status = urb->status;

        mos7840_port = urb->context;
        if (!mos7840_port) {
                dbg("%s", "NULL mos7840_port pointer");
                mos7840_port->read_urb_busy = false;
                return;
        }

        if (status) {
                dbg("nonzero read bulk status received: %d", status);
                mos7840_port->read_urb_busy = false;
                return;
        }

        port = (struct usb_serial_port *)mos7840_port->port;
        if (mos7840_port_paranoia_check(port, __func__)) {
                dbg("%s", "Port Paranoia failed");
                mos7840_port->read_urb_busy = false;
                return;
        }

        serial = mos7840_get_usb_serial(port, __func__);
        if (!serial) {
                dbg("%s", "Bad serial pointer");
                mos7840_port->read_urb_busy = false;
                return;
        }

        dbg("%s", "Entering... ");

        data = urb->transfer_buffer;

        dbg("%s", "Entering ...........");

        if (urb->actual_length) {
                tty = tty_port_tty_get(&mos7840_port->port->port);
                if (tty) {
                        tty_buffer_request_room(tty, urb->actual_length);
                        tty_insert_flip_string(tty, data, urb->actual_length);
                        dbg(" %s ", data);
                        tty_flip_buffer_push(tty);
                        tty_kref_put(tty);
                }
                mos7840_port->icount.rx += urb->actual_length;
                smp_wmb();
                dbg("mos7840_port->icount.rx is %d:",
                    mos7840_port->icount.rx);
        }

        if (!mos7840_port->read_urb) {
                dbg("%s", "URB KILLED !!!");
                mos7840_port->read_urb_busy = false;
                return;
        }


        mos7840_port->read_urb->dev = serial->dev;

        mos7840_port->read_urb_busy = true;
        retval = usb_submit_urb(mos7840_port->read_urb, GFP_ATOMIC);

        if (retval) {
                dbg("usb_submit_urb(read bulk) failed, retval = %d", retval);
                mos7840_port->read_urb_busy = false;
        }
}

/*****************************************************************************
 * mos7840_bulk_out_data_callback
 *      this is the callback function for when we have finished sending
 *      serial data on the bulk out endpoint.
 *****************************************************************************/

static void mos7840_bulk_out_data_callback(struct urb *urb)
{
        struct moschip_port *mos7840_port;
        struct tty_struct *tty;
        int status = urb->status;
        int i;

        mos7840_port = urb->context;
        spin_lock(&mos7840_port->pool_lock);
        for (i = 0; i < NUM_URBS; i++) {
                if (urb == mos7840_port->write_urb_pool[i]) {
                        mos7840_port->busy[i] = 0;
                        break;
                }
        }
        spin_unlock(&mos7840_port->pool_lock);

        if (status) {
                dbg("nonzero write bulk status received:%d", status);
                return;
        }

        if (mos7840_port_paranoia_check(mos7840_port->port, __func__)) {
                dbg("%s", "Port Paranoia failed");
                return;
        }

        dbg("%s", "Entering .........");

        tty = tty_port_tty_get(&mos7840_port->port->port);
        if (tty && mos7840_port->open)
                tty_wakeup(tty);
        tty_kref_put(tty);

}

/************************************************************************/
/*       D R I V E R  T T Y  I N T E R F A C E  F U N C T I O N S       */
/************************************************************************/
#ifdef MCSSerialProbe
static int mos7840_serial_probe(struct usb_serial *serial,
                                const struct usb_device_id *id)
{

        /*need to implement the mode_reg reading and updating\
           structures usb_serial_ device_type\
           (i.e num_ports, num_bulkin,bulkout etc) */
        /* Also we can update the changes  attach */
        return 1;
}
#endif

/*****************************************************************************
 * mos7840_open
 *      this function is called by the tty driver when a port is opened
 *      If successful, we return 0
 *      Otherwise we return a negative error number.
 *****************************************************************************/

static int mos7840_open(struct tty_struct *tty, struct usb_serial_port *port)
{
        int response;
        int j;
        struct usb_serial *serial;
        struct urb *urb;
        __u16 Data;
        int status;
        struct moschip_port *mos7840_port;
        struct moschip_port *port0;

        dbg ("%s enter", __func__);

        if (mos7840_port_paranoia_check(port, __func__)) {
                dbg("%s", "Port Paranoia failed");
                return -ENODEV;
        }

        serial = port->serial;

        if (mos7840_serial_paranoia_check(serial, __func__)) {
                dbg("%s", "Serial Paranoia failed");
                return -ENODEV;
        }

        mos7840_port = mos7840_get_port_private(port);
        port0 = mos7840_get_port_private(serial->port[0]);

        if (mos7840_port == NULL || port0 == NULL)
                return -ENODEV;

        usb_clear_halt(serial->dev, port->write_urb->pipe);
        usb_clear_halt(serial->dev, port->read_urb->pipe);
        port0->open_ports++;

        /* Initialising the write urb pool */
        for (j = 0; j < NUM_URBS; ++j) {
                urb = usb_alloc_urb(0, GFP_KERNEL);
                mos7840_port->write_urb_pool[j] = urb;

                if (urb == NULL) {
                        dev_err(&port->dev, "No more urbs???\n");
                        continue;
                }

                urb->transfer_buffer = kmalloc(URB_TRANSFER_BUFFER_SIZE,
                                                                GFP_KERNEL);
                if (!urb->transfer_buffer) {
                        usb_free_urb(urb);
                        mos7840_port->write_urb_pool[j] = NULL;
                        dev_err(&port->dev,
                                "%s-out of memory for urb buffers.\n",
                                __func__);
                        continue;
                }
        }

/*****************************************************************************
 * Initialize MCS7840 -- Write Init values to corresponding Registers
 *
 * Register Index
 * 1 : IER
 * 2 : FCR
 * 3 : LCR
 * 4 : MCR
 *
 * 0x08 : SP1/2 Control Reg
 *****************************************************************************/

        /* NEED to check the following Block */

        Data = 0x0;
        status = mos7840_get_reg_sync(port, mos7840_port->SpRegOffset, &Data);
        if (status < 0) {
                dbg("Reading Spreg failed");
                return -1;
        }
        Data |= 0x80;
        status = mos7840_set_reg_sync(port, mos7840_port->SpRegOffset, Data);
        if (status < 0) {
                dbg("writing Spreg failed");
                return -1;
        }

        Data &= ~0x80;
        status = mos7840_set_reg_sync(port, mos7840_port->SpRegOffset, Data);
        if (status < 0) {
                dbg("writing Spreg failed");
                return -1;
        }
        /* End of block to be checked */

        Data = 0x0;
        status = mos7840_get_reg_sync(port, mos7840_port->ControlRegOffset,
                                                                        &Data);
        if (status < 0) {
                dbg("Reading Controlreg failed");
                return -1;
        }
        Data |= 0x08;           /* Driver done bit */
        Data |= 0x20;           /* rx_disable */
        status = mos7840_set_reg_sync(port,
                                mos7840_port->ControlRegOffset, Data);
        if (status < 0) {
                dbg("writing Controlreg failed");
                return -1;
        }
        /* do register settings here */
        /* Set all regs to the device default values. */
        /***********************************
         * First Disable all interrupts.
         ***********************************/
        Data = 0x00;
        status = mos7840_set_uart_reg(port, INTERRUPT_ENABLE_REGISTER, Data);
        if (status < 0) {
                dbg("disabling interrupts failed");
                return -1;
        }
        /* Set FIFO_CONTROL_REGISTER to the default value */
        Data = 0x00;
        status = mos7840_set_uart_reg(port, FIFO_CONTROL_REGISTER, Data);
        if (status < 0) {
                dbg("Writing FIFO_CONTROL_REGISTER  failed");
                return -1;
        }

        Data = 0xcf;
        status = mos7840_set_uart_reg(port, FIFO_CONTROL_REGISTER, Data);
        if (status < 0) {
                dbg("Writing FIFO_CONTROL_REGISTER  failed");
                return -1;
        }

        Data = 0x03;
        status = mos7840_set_uart_reg(port, LINE_CONTROL_REGISTER, Data);
        mos7840_port->shadowLCR = Data;

        Data = 0x0b;
        status = mos7840_set_uart_reg(port, MODEM_CONTROL_REGISTER, Data);
        mos7840_port->shadowMCR = Data;

        Data = 0x00;
        status = mos7840_get_uart_reg(port, LINE_CONTROL_REGISTER, &Data);
        mos7840_port->shadowLCR = Data;

        Data |= SERIAL_LCR_DLAB;        /* data latch enable in LCR 0x80 */
        status = mos7840_set_uart_reg(port, LINE_CONTROL_REGISTER, Data);

        Data = 0x0c;
        status = mos7840_set_uart_reg(port, DIVISOR_LATCH_LSB, Data);

        Data = 0x0;
        status = mos7840_set_uart_reg(port, DIVISOR_LATCH_MSB, Data);

        Data = 0x00;
        status = mos7840_get_uart_reg(port, LINE_CONTROL_REGISTER, &Data);

        Data = Data & ~SERIAL_LCR_DLAB;
        status = mos7840_set_uart_reg(port, LINE_CONTROL_REGISTER, Data);
        mos7840_port->shadowLCR = Data;

        /* clearing Bulkin and Bulkout Fifo */
        Data = 0x0;
        status = mos7840_get_reg_sync(port, mos7840_port->SpRegOffset, &Data);

        Data = Data | 0x0c;
        status = mos7840_set_reg_sync(port, mos7840_port->SpRegOffset, Data);

        Data = Data & ~0x0c;
        status = mos7840_set_reg_sync(port, mos7840_port->SpRegOffset, Data);
        /* Finally enable all interrupts */
        Data = 0x0c;
        status = mos7840_set_uart_reg(port, INTERRUPT_ENABLE_REGISTER, Data);

        /* clearing rx_disable */
        Data = 0x0;
        status = mos7840_get_reg_sync(port, mos7840_port->ControlRegOffset,
                                                                        &Data);
        Data = Data & ~0x20;
        status = mos7840_set_reg_sync(port, mos7840_port->ControlRegOffset,
                                                                        Data);

        /* rx_negate */
        Data = 0x0;
        status = mos7840_get_reg_sync(port, mos7840_port->ControlRegOffset,
                                                                        &Data);
        Data = Data | 0x10;
        status = mos7840_set_reg_sync(port, mos7840_port->ControlRegOffset,
                                                                        Data);

        /* Check to see if we've set up our endpoint info yet    *
         * (can't set it up in mos7840_startup as the structures *
         * were not set up at that time.)                        */
        if (port0->open_ports == 1) {
                if (serial->port[0]->interrupt_in_buffer == NULL) {
                        /* set up interrupt urb */
                        usb_fill_int_urb(serial->port[0]->interrupt_in_urb,
                                serial->dev,
                                usb_rcvintpipe(serial->dev,
                                serial->port[0]->interrupt_in_endpointAddress),
                                serial->port[0]->interrupt_in_buffer,
                                serial->port[0]->interrupt_in_urb->
                                transfer_buffer_length,
                                mos7840_interrupt_callback,
                                serial,
                                serial->port[0]->interrupt_in_urb->interval);

                        /* start interrupt read for mos7840               *
                         * will continue as long as mos7840 is connected  */

                        response =
                            usb_submit_urb(serial->port[0]->interrupt_in_urb,
                                           GFP_KERNEL);
                        if (response) {
                                dev_err(&port->dev, "%s - Error %d submitting "
                                        "interrupt urb\n", __func__, response);
                        }

                }

        }

        /* see if we've set up our endpoint info yet   *
         * (can't set it up in mos7840_startup as the  *
         * structures were not set up at that time.)   */

        dbg("port number is %d", port->number);
        dbg("serial number is %d", port->serial->minor);
        dbg("Bulkin endpoint is %d", port->bulk_in_endpointAddress);
        dbg("BulkOut endpoint is %d", port->bulk_out_endpointAddress);
        dbg("Interrupt endpoint is %d", port->interrupt_in_endpointAddress);
        dbg("port's number in the device is %d", mos7840_port->port_num);
        mos7840_port->read_urb = port->read_urb;

        /* set up our bulk in urb */

        usb_fill_bulk_urb(mos7840_port->read_urb,
                          serial->dev,
                          usb_rcvbulkpipe(serial->dev,
                                          port->bulk_in_endpointAddress),
                          port->bulk_in_buffer,
                          mos7840_port->read_urb->transfer_buffer_length,
                          mos7840_bulk_in_callback, mos7840_port);

        dbg("mos7840_open: bulkin endpoint is %d",
            port->bulk_in_endpointAddress);
        mos7840_port->read_urb_busy = true;
        response = usb_submit_urb(mos7840_port->read_urb, GFP_KERNEL);
        if (response) {
                dev_err(&port->dev, "%s - Error %d submitting control urb\n",
                        __func__, response);
                mos7840_port->read_urb_busy = false;
        }

        /* initialize our wait queues */
        init_waitqueue_head(&mos7840_port->wait_chase);
        init_waitqueue_head(&mos7840_port->delta_msr_wait);

        /* initialize our icount structure */
        memset(&(mos7840_port->icount), 0x00, sizeof(mos7840_port->icount));

        /* initialize our port settings */
        /* Must set to enable ints! */
        mos7840_port->shadowMCR = MCR_MASTER_IE;
        /* send a open port command */
        mos7840_port->open = 1;
        /* mos7840_change_port_settings(mos7840_port,old_termios); */
        mos7840_port->icount.tx = 0;
        mos7840_port->icount.rx = 0;

        dbg("usb_serial serial:%p       mos7840_port:%p\n      usb_serial_port port:%p",
                                serial, mos7840_port, port);

        dbg ("%s leave", __func__);

        return 0;

}

/*****************************************************************************
 * mos7840_chars_in_buffer
 *      this function is called by the tty driver when it wants to know how many
 *      bytes of data we currently have outstanding in the port (data that has
 *      been written, but hasn't made it out the port yet)
 *      If successful, we return the number of bytes left to be written in the
 *      system,
 *      Otherwise we return zero.
 *****************************************************************************/

static int mos7840_chars_in_buffer(struct tty_struct *tty)
{
        struct usb_serial_port *port = tty->driver_data;
        int i;
        int chars = 0;
        unsigned long flags;
        struct moschip_port *mos7840_port;

        dbg("%s", " mos7840_chars_in_buffer:entering ...........");

        if (mos7840_port_paranoia_check(port, __func__)) {
                dbg("%s", "Invalid port");
                return 0;
        }

        mos7840_port = mos7840_get_port_private(port);
        if (mos7840_port == NULL) {
                dbg("%s", "mos7840_break:leaving ...........");
                return 0;
        }

        spin_lock_irqsave(&mos7840_port->pool_lock, flags);
        for (i = 0; i < NUM_URBS; ++i)
                if (mos7840_port->busy[i])
                        chars += URB_TRANSFER_BUFFER_SIZE;
        spin_unlock_irqrestore(&mos7840_port->pool_lock, flags);
        dbg("%s - returns %d", __func__, chars);
        return chars;

}

/*****************************************************************************
 * mos7840_close
 *      this function is called by the tty driver when a port is closed
 *****************************************************************************/

static void mos7840_close(struct usb_serial_port *port)
{
        struct usb_serial *serial;
        struct moschip_port *mos7840_port;
        struct moschip_port *port0;
        int j;
        __u16 Data;

        dbg("%s", "mos7840_close:entering...");

        if (mos7840_port_paranoia_check(port, __func__)) {
                dbg("%s", "Port Paranoia failed");
                return;
        }

        serial = mos7840_get_usb_serial(port, __func__);
        if (!serial) {
                dbg("%s", "Serial Paranoia failed");
                return;
        }

        mos7840_port = mos7840_get_port_private(port);
        port0 = mos7840_get_port_private(serial->port[0]);

        if (mos7840_port == NULL || port0 == NULL)
                return;

        for (j = 0; j < NUM_URBS; ++j)
                usb_kill_urb(mos7840_port->write_urb_pool[j]);

        /* Freeing Write URBs */
        for (j = 0; j < NUM_URBS; ++j) {
                if (mos7840_port->write_urb_pool[j]) {
                        if (mos7840_port->write_urb_pool[j]->transfer_buffer)
                                kfree(mos7840_port->write_urb_pool[j]->
                                      transfer_buffer);

                        usb_free_urb(mos7840_port->write_urb_pool[j]);
                }
        }

        /* While closing port, shutdown all bulk read, write  *
         * and interrupt read if they exists                  */
        if (serial->dev) {
                if (mos7840_port->write_urb) {
                        dbg("%s", "Shutdown bulk write");
                        usb_kill_urb(mos7840_port->write_urb);
                }
                if (mos7840_port->read_urb) {
                        dbg("%s", "Shutdown bulk read");
                        usb_kill_urb(mos7840_port->read_urb);
                        mos7840_port->read_urb_busy = false;
                }
                if ((&mos7840_port->control_urb)) {
                        dbg("%s", "Shutdown control read");
                        /*/      usb_kill_urb (mos7840_port->control_urb); */
                }
        }
/*      if(mos7840_port->ctrl_buf != NULL) */
/*              kfree(mos7840_port->ctrl_buf); */
        port0->open_ports--;
        dbg("mos7840_num_open_ports in close%d:in port%d",
            port0->open_ports, port->number);
        if (port0->open_ports == 0) {
                if (serial->port[0]->interrupt_in_urb) {
                        dbg("%s", "Shutdown interrupt_in_urb");
                        usb_kill_urb(serial->port[0]->interrupt_in_urb);
                }
        }

        if (mos7840_port->write_urb) {
                /* if this urb had a transfer buffer already (old tx) free it */
                if (mos7840_port->write_urb->transfer_buffer != NULL)
                        kfree(mos7840_port->write_urb->transfer_buffer);
                usb_free_urb(mos7840_port->write_urb);
        }

        Data = 0x0;
        mos7840_set_uart_reg(port, MODEM_CONTROL_REGISTER, Data);

        Data = 0x00;
        mos7840_set_uart_reg(port, INTERRUPT_ENABLE_REGISTER, Data);

        mos7840_port->open = 0;

        dbg("%s", "Leaving ............");
}

/************************************************************************
 *
 * mos7840_block_until_chase_response
 *
 *      This function will block the close until one of the following:
 *              1. Response to our Chase comes from mos7840
 *              2. A timeout of 10 seconds without activity has expired
 *                 (1K of mos7840 data @ 2400 baud ==> 4 sec to empty)
 *
 ************************************************************************/

static void mos7840_block_until_chase_response(struct tty_struct *tty,
                                        struct moschip_port *mos7840_port)
{
        int timeout = 1 * HZ;
        int wait = 10;
        int count;

        while (1) {
                count = mos7840_chars_in_buffer(tty);

                /* Check for Buffer status */
                if (count <= 0)
                        return;

                /* Block the thread for a while */
                interruptible_sleep_on_timeout(&mos7840_port->wait_chase,
                                               timeout);
                /* No activity.. count down section */
                wait--;
                if (wait == 0) {
                        dbg("%s - TIMEOUT", __func__);
                        return;
                } else {
                        /* Reset timeout value back to seconds */
                        wait = 10;
                }
        }

}

/*****************************************************************************
 * mos7840_break
 *      this function sends a break to the port
 *****************************************************************************/
static void mos7840_break(struct tty_struct *tty, int break_state)
{
        struct usb_serial_port *port = tty->driver_data;
        unsigned char data;
        struct usb_serial *serial;
        struct moschip_port *mos7840_port;

        dbg("%s", "Entering ...........");
        dbg("mos7840_break: Start");

        if (mos7840_port_paranoia_check(port, __func__)) {
                dbg("%s", "Port Paranoia failed");
                return;
        }

        serial = mos7840_get_usb_serial(port, __func__);
        if (!serial) {
                dbg("%s", "Serial Paranoia failed");
                return;
        }

        mos7840_port = mos7840_get_port_private(port);

        if (mos7840_port == NULL)
                return;

        if (serial->dev)
                /* flush and block until tx is empty */
                mos7840_block_until_chase_response(tty, mos7840_port);

        if (break_state == -1)
                data = mos7840_port->shadowLCR | LCR_SET_BREAK;
        else
                data = mos7840_port->shadowLCR & ~LCR_SET_BREAK;

        /* FIXME: no locking on shadowLCR anywhere in driver */
        mos7840_port->shadowLCR = data;
        dbg("mcs7840_break mos7840_port->shadowLCR is %x",
            mos7840_port->shadowLCR);
        mos7840_set_uart_reg(port, LINE_CONTROL_REGISTER,
                             mos7840_port->shadowLCR);

        return;
}

/*****************************************************************************
 * mos7840_write_room
 *      this function is called by the tty driver when it wants to know how many
 *      bytes of data we can accept for a specific port.
 *      If successful, we return the amount of room that we have for this port
 *      Otherwise we return a negative error number.
 *****************************************************************************/

static int mos7840_write_room(struct tty_struct *tty)
{
        struct usb_serial_port *port = tty->driver_data;
        int i;
        int room = 0;
        unsigned long flags;
        struct moschip_port *mos7840_port;

        dbg("%s", " mos7840_write_room:entering ...........");

        if (mos7840_port_paranoia_check(port, __func__)) {
                dbg("%s", "Invalid port");
                dbg("%s", " mos7840_write_room:leaving ...........");
                return -1;
        }

        mos7840_port = mos7840_get_port_private(port);
        if (mos7840_port == NULL) {
                dbg("%s", "mos7840_break:leaving ...........");
                return -1;
        }

        spin_lock_irqsave(&mos7840_port->pool_lock, flags);
        for (i = 0; i < NUM_URBS; ++i) {
                if (!mos7840_port->busy[i])
                        room += URB_TRANSFER_BUFFER_SIZE;
        }
        spin_unlock_irqrestore(&mos7840_port->pool_lock, flags);

        room = (room == 0) ? 0 : room - URB_TRANSFER_BUFFER_SIZE + 1;
        dbg("%s - returns %d", __func__, room);
        return room;

}

/*****************************************************************************
 * mos7840_write
 *      this function is called by the tty driver when data should be written to
 *      the port.
 *      If successful, we return the number of bytes written, otherwise we
 *      return a negative error number.
 *****************************************************************************/

static int mos7840_write(struct tty_struct *tty, struct usb_serial_port *port,
                         const unsigned char *data, int count)
{
        int status;
        int i;
        int bytes_sent = 0;
        int transfer_size;
        unsigned long flags;

        struct moschip_port *mos7840_port;
        struct usb_serial *serial;
        struct urb *urb;
        /* __u16 Data; */
        const unsigned char *current_position = data;
        unsigned char *data1;
        dbg("%s", "entering ...........");
        /* dbg("mos7840_write: mos7840_port->shadowLCR is %x",
                                        mos7840_port->shadowLCR); */

#ifdef NOTMOS7840
        Data = 0x00;
        status = mos7840_get_uart_reg(port, LINE_CONTROL_REGISTER, &Data);
        mos7840_port->shadowLCR = Data;
        dbg("mos7840_write: LINE_CONTROL_REGISTER is %x", Data);
        dbg("mos7840_write: mos7840_port->shadowLCR is %x",
            mos7840_port->shadowLCR);

        /* Data = 0x03; */
        /* status = mos7840_set_uart_reg(port,LINE_CONTROL_REGISTER,Data); */
        /* mos7840_port->shadowLCR=Data;//Need to add later */

        Data |= SERIAL_LCR_DLAB;        /* data latch enable in LCR 0x80 */
        status = mos7840_set_uart_reg(port, LINE_CONTROL_REGISTER, Data);

        /* Data = 0x0c; */
        /* status = mos7840_set_uart_reg(port,DIVISOR_LATCH_LSB,Data); */
        Data = 0x00;
        status = mos7840_get_uart_reg(port, DIVISOR_LATCH_LSB, &Data);
        dbg("mos7840_write:DLL value is %x", Data);

        Data = 0x0;
        status = mos7840_get_uart_reg(port, DIVISOR_LATCH_MSB, &Data);
        dbg("mos7840_write:DLM value is %x", Data);

        Data = Data & ~SERIAL_LCR_DLAB;
        dbg("mos7840_write: mos7840_port->shadowLCR is %x",
            mos7840_port->shadowLCR);
        status = mos7840_set_uart_reg(port, LINE_CONTROL_REGISTER, Data);
#endif

        if (mos7840_port_paranoia_check(port, __func__)) {
                dbg("%s", "Port Paranoia failed");
                return -1;
        }

        serial = port->serial;
        if (mos7840_serial_paranoia_check(serial, __func__)) {
                dbg("%s", "Serial Paranoia failed");
                return -1;
        }

        mos7840_port = mos7840_get_port_private(port);
        if (mos7840_port == NULL) {
                dbg("%s", "mos7840_port is NULL");
                return -1;
        }

        /* try to find a free urb in the list */
        urb = NULL;

        spin_lock_irqsave(&mos7840_port->pool_lock, flags);
        for (i = 0; i < NUM_URBS; ++i) {
                if (!mos7840_port->busy[i]) {
                        mos7840_port->busy[i] = 1;
                        urb = mos7840_port->write_urb_pool[i];
                        dbg("URB:%d", i);
                        break;
                }
        }
        spin_unlock_irqrestore(&mos7840_port->pool_lock, flags);

        if (urb == NULL) {
                dbg("%s - no more free urbs", __func__);
                goto exit;
        }

        if (urb->transfer_buffer == NULL) {
                urb->transfer_buffer =
                    kmalloc(URB_TRANSFER_BUFFER_SIZE, GFP_KERNEL);

                if (urb->transfer_buffer == NULL) {
                        dev_err(&port->dev, "%s no more kernel memory...\n",
                                __func__);
                        goto exit;
                }
        }
        transfer_size = min(count, URB_TRANSFER_BUFFER_SIZE);

        memcpy(urb->transfer_buffer, current_position, transfer_size);

        /* fill urb with data and submit  */
        usb_fill_bulk_urb(urb,
                          serial->dev,
                          usb_sndbulkpipe(serial->dev,
                                          port->bulk_out_endpointAddress),
                          urb->transfer_buffer,
                          transfer_size,
                          mos7840_bulk_out_data_callback, mos7840_port);

        data1 = urb->transfer_buffer;
        dbg("bulkout endpoint is %d", port->bulk_out_endpointAddress);

        /* send it down the pipe */
        status = usb_submit_urb(urb, GFP_ATOMIC);

        if (status) {
                mos7840_port->busy[i] = 0;
                dev_err(&port->dev, "%s - usb_submit_urb(write bulk) failed "
                        "with status = %d\n", __func__, status);
                bytes_sent = status;
                goto exit;
        }
        bytes_sent = transfer_size;
        mos7840_port->icount.tx += transfer_size;
        smp_wmb();
        dbg("mos7840_port->icount.tx is %d:", mos7840_port->icount.tx);
exit:
        return bytes_sent;

}

/*****************************************************************************
 * mos7840_throttle
 *      this function is called by the tty driver when it wants to stop the data
 *      being read from the port.
 *****************************************************************************/

static void mos7840_throttle(struct tty_struct *tty)
{
        struct usb_serial_port *port = tty->driver_data;
        struct moschip_port *mos7840_port;
        int status;

        if (mos7840_port_paranoia_check(port, __func__)) {
                dbg("%s", "Invalid port");
                return;
        }

        dbg("- port %d", port->number);

        mos7840_port = mos7840_get_port_private(port);

        if (mos7840_port == NULL)
                return;

        if (!mos7840_port->open) {
                dbg("%s", "port not opened");
                return;
        }

        dbg("%s", "Entering ..........");

        /* if we are implementing XON/XOFF, send the stop character */
        if (I_IXOFF(tty)) {
                unsigned char stop_char = STOP_CHAR(tty);
                status = mos7840_write(tty, port, &stop_char, 1);
                if (status <= 0)
                        return;
        }
        /* if we are implementing RTS/CTS, toggle that line */
        if (tty->termios->c_cflag & CRTSCTS) {
                mos7840_port->shadowMCR &= ~MCR_RTS;
                status = mos7840_set_uart_reg(port, MODEM_CONTROL_REGISTER,
                                         mos7840_port->shadowMCR);
                if (status < 0)
                        return;
        }

        return;
}

/*****************************************************************************
 * mos7840_unthrottle
 *      this function is called by the tty driver when it wants to resume
 *      the data being read from the port (called after mos7840_throttle is
 *      called)
 *****************************************************************************/
static void mos7840_unthrottle(struct tty_struct *tty)
{
        struct usb_serial_port *port = tty->driver_data;
        int status;
        struct moschip_port *mos7840_port = mos7840_get_port_private(port);

        if (mos7840_port_paranoia_check(port, __func__)) {
                dbg("%s", "Invalid port");
                return;
        }

        if (mos7840_port == NULL)
                return;

        if (!mos7840_port->open) {
                dbg("%s - port not opened", __func__);
                return;
        }

        dbg("%s", "Entering ..........");

        /* if we are implementing XON/XOFF, send the start character */
        if (I_IXOFF(tty)) {
                unsigned char start_char = START_CHAR(tty);
                status = mos7840_write(tty, port, &start_char, 1);
                if (status <= 0)
                        return;
        }

        /* if we are implementing RTS/CTS, toggle that line */
        if (tty->termios->c_cflag & CRTSCTS) {
                mos7840_port->shadowMCR |= MCR_RTS;
                status = mos7840_set_uart_reg(port, MODEM_CONTROL_REGISTER,
                                         mos7840_port->shadowMCR);
                if (status < 0)
                        return;
        }
}

static int mos7840_tiocmget(struct tty_struct *tty, struct file *file)
{
        struct usb_serial_port *port = tty->driver_data;
        struct moschip_port *mos7840_port;
        unsigned int result;
        __u16 msr;
        __u16 mcr;
        int status;
        mos7840_port = mos7840_get_port_private(port);

        dbg("%s - port %d", __func__, port->number);

        if (mos7840_port == NULL)
                return -ENODEV;

        status = mos7840_get_uart_reg(port, MODEM_STATUS_REGISTER, &msr);
        status = mos7840_get_uart_reg(port, MODEM_CONTROL_REGISTER, &mcr);
        result = ((mcr & MCR_DTR) ? TIOCM_DTR : 0)
            | ((mcr & MCR_RTS) ? TIOCM_RTS : 0)
            | ((mcr & MCR_LOOPBACK) ? TIOCM_LOOP : 0)
            | ((msr & MOS7840_MSR_CTS) ? TIOCM_CTS : 0)
            | ((msr & MOS7840_MSR_CD) ? TIOCM_CAR : 0)
            | ((msr & MOS7840_MSR_RI) ? TIOCM_RI : 0)
            | ((msr & MOS7840_MSR_DSR) ? TIOCM_DSR : 0);

        dbg("%s - 0x%04X", __func__, result);

        return result;
}

static int mos7840_tiocmset(struct tty_struct *tty, struct file *file,
                            unsigned int set, unsigned int clear)
{
        struct usb_serial_port *port = tty->driver_data;
        struct moschip_port *mos7840_port;
        unsigned int mcr;
        int status;

        dbg("%s - port %d", __func__, port->number);

        mos7840_port = mos7840_get_port_private(port);

        if (mos7840_port == NULL)
                return -ENODEV;

        /* FIXME: What locks the port registers ? */
        mcr = mos7840_port->shadowMCR;
        if (clear & TIOCM_RTS)
                mcr &= ~MCR_RTS;
        if (clear & TIOCM_DTR)
                mcr &= ~MCR_DTR;
        if (clear & TIOCM_LOOP)
                mcr &= ~MCR_LOOPBACK;

        if (set & TIOCM_RTS)
                mcr |= MCR_RTS;
        if (set & TIOCM_DTR)
                mcr |= MCR_DTR;
        if (set & TIOCM_LOOP)
                mcr |= MCR_LOOPBACK;

        mos7840_port->shadowMCR = mcr;

        status = mos7840_set_uart_reg(port, MODEM_CONTROL_REGISTER, mcr);
        if (status < 0) {
                dbg("setting MODEM_CONTROL_REGISTER Failed");
                return status;
        }

        return 0;
}

/*****************************************************************************
 * mos7840_calc_baud_rate_divisor
 *      this function calculates the proper baud rate divisor for the specified
 *      baud rate.
 *****************************************************************************/
static int mos7840_calc_baud_rate_divisor(int baudRate, int *divisor,
                                          __u16 *clk_sel_val)
{

        dbg("%s - %d", __func__, baudRate);

        if (baudRate <= 115200) {
                *divisor = 115200 / baudRate;
                *clk_sel_val = 0x0;
        }
        if ((baudRate > 115200) && (baudRate <= 230400)) {
                *divisor = 230400 / baudRate;
                *clk_sel_val = 0x10;
        } else if ((baudRate > 230400) && (baudRate <= 403200)) {
                *divisor = 403200 / baudRate;
                *clk_sel_val = 0x20;
        } else if ((baudRate > 403200) && (baudRate <= 460800)) {
                *divisor = 460800 / baudRate;
                *clk_sel_val = 0x30;
        } else if ((baudRate > 460800) && (baudRate <= 806400)) {
                *divisor = 806400 / baudRate;
                *clk_sel_val = 0x40;
        } else if ((baudRate > 806400) && (baudRate <= 921600)) {
                *divisor = 921600 / baudRate;
                *clk_sel_val = 0x50;
        } else if ((baudRate > 921600) && (baudRate <= 1572864)) {
                *divisor = 1572864 / baudRate;
                *clk_sel_val = 0x60;
        } else if ((baudRate > 1572864) && (baudRate <= 3145728)) {
                *divisor = 3145728 / baudRate;
                *clk_sel_val = 0x70;
        }
        return 0;

#ifdef NOTMCS7840

        for (i = 0; i < ARRAY_SIZE(mos7840_divisor_table); i++) {
                if (mos7840_divisor_table[i].BaudRate == baudrate) {
                        *divisor = mos7840_divisor_table[i].Divisor;
                        return 0;
                }
        }

        /* After trying for all the standard baud rates    *
         * Try calculating the divisor for this baud rate  */

        if (baudrate > 75 && baudrate < 230400) {
                /* get the divisor */
                custom = (__u16) (230400L / baudrate);

                /* Check for round off */
                round1 = (__u16) (2304000L / baudrate);
                round = (__u16) (round1 - (custom * 10));
                if (round > 4)
                        custom++;
                *divisor = custom;

                dbg(" Baud %d = %d", baudrate, custom);
                return 0;
        }

        dbg("%s", " Baud calculation Failed...");
        return -1;
#endif
}

/*****************************************************************************
 * mos7840_send_cmd_write_baud_rate
 *      this function sends the proper command to change the baud rate of the
 *      specified port.
 *****************************************************************************/

static int mos7840_send_cmd_write_baud_rate(struct moschip_port *mos7840_port,
                                            int baudRate)
{
        int divisor = 0;
        int status;
        __u16 Data;
        unsigned char number;
        __u16 clk_sel_val;
        struct usb_serial_port *port;

        if (mos7840_port == NULL)
                return -1;

        port = (struct usb_serial_port *)mos7840_port->port;
        if (mos7840_port_paranoia_check(port, __func__)) {
                dbg("%s", "Invalid port");
                return -1;
        }

        if (mos7840_serial_paranoia_check(port->serial, __func__)) {
                dbg("%s", "Invalid Serial");
                return -1;
        }

        dbg("%s", "Entering ..........");

        number = mos7840_port->port->number - mos7840_port->port->serial->minor;

        dbg("%s - port = %d, baud = %d", __func__,
            mos7840_port->port->number, baudRate);
        /* reset clk_uart_sel in spregOffset */
        if (baudRate > 115200) {
#ifdef HW_flow_control
                /* NOTE: need to see the pther register to modify */
                /* setting h/w flow control bit to 1 */
                Data = 0x2b;
                mos7840_port->shadowMCR = Data;
                status = mos7840_set_uart_reg(port, MODEM_CONTROL_REGISTER,
                                                                        Data);
                if (status < 0) {
                        dbg("Writing spreg failed in set_serial_baud");
                        return -1;
                }
#endif

        } else {
#ifdef HW_flow_control
                / *setting h/w flow control bit to 0 */
                Data = 0xb;
                mos7840_port->shadowMCR = Data;
                status = mos7840_set_uart_reg(port, MODEM_CONTROL_REGISTER,
                                                                        Data);
                if (status < 0) {
                        dbg("Writing spreg failed in set_serial_baud");
                        return -1;
                }
#endif

        }

        if (1) {                /* baudRate <= 115200) */
                clk_sel_val = 0x0;
                Data = 0x0;
                status = mos7840_calc_baud_rate_divisor(baudRate, &divisor,
                                                   &clk_sel_val);
                status = mos7840_get_reg_sync(port, mos7840_port->SpRegOffset,
                                                                 &Data);
                if (status < 0) {
                        dbg("reading spreg failed in set_serial_baud");
                        return -1;
                }
                Data = (Data & 0x8f) | clk_sel_val;
                status = mos7840_set_reg_sync(port, mos7840_port->SpRegOffset,
                                                                Data);
                if (status < 0) {
                        dbg("Writing spreg failed in set_serial_baud");
                        return -1;
                }
                /* Calculate the Divisor */

                if (status) {
                        dev_err(&port->dev, "%s - bad baud rate\n", __func__);
                        return status;
                }
                /* Enable access to divisor latch */
                Data = mos7840_port->shadowLCR | SERIAL_LCR_DLAB;
                mos7840_port->shadowLCR = Data;
                mos7840_set_uart_reg(port, LINE_CONTROL_REGISTER, Data);

                /* Write the divisor */
                Data = (unsigned char)(divisor & 0xff);
                dbg("set_serial_baud Value to write DLL is %x", Data);
                mos7840_set_uart_reg(port, DIVISOR_LATCH_LSB, Data);

                Data = (unsigned char)((divisor & 0xff00) >> 8);
                dbg("set_serial_baud Value to write DLM is %x", Data);
                mos7840_set_uart_reg(port, DIVISOR_LATCH_MSB, Data);

                /* Disable access to divisor latch */
                Data = mos7840_port->shadowLCR & ~SERIAL_LCR_DLAB;
                mos7840_port->shadowLCR = Data;
                mos7840_set_uart_reg(port, LINE_CONTROL_REGISTER, Data);

        }
        return status;
}

/*****************************************************************************
 * mos7840_change_port_settings
 *      This routine is called to set the UART on the device to match
 *      the specified new settings.
 *****************************************************************************/

static void mos7840_change_port_settings(struct tty_struct *tty,
        struct moschip_port *mos7840_port, struct ktermios *old_termios)
{
        int baud;
        unsigned cflag;
        unsigned iflag;
        __u8 lData;
        __u8 lParity;
        __u8 lStop;
        int status;
        __u16 Data;
        struct usb_serial_port *port;
        struct usb_serial *serial;

        if (mos7840_port == NULL)
                return;

        port = (struct usb_serial_port *)mos7840_port->port;

        if (mos7840_port_paranoia_check(port, __func__)) {
                dbg("%s", "Invalid port");
                return;
        }

        if (mos7840_serial_paranoia_check(port->serial, __func__)) {
                dbg("%s", "Invalid Serial");
                return;
        }

        serial = port->serial;

        dbg("%s - port %d", __func__, mos7840_port->port->number);

        if (!mos7840_port->open) {
                dbg("%s - port not opened", __func__);
                return;
        }

        dbg("%s", "Entering ..........");

        lData = LCR_BITS_8;
        lStop = LCR_STOP_1;
        lParity = LCR_PAR_NONE;

        cflag = tty->termios->c_cflag;
        iflag = tty->termios->c_iflag;

        /* Change the number of bits */
        if (cflag & CSIZE) {
                switch (cflag & CSIZE) {
                case CS5:
                        lData = LCR_BITS_5;
                        break;

                case CS6:
                        lData = LCR_BITS_6;
                        break;

                case CS7:
                        lData = LCR_BITS_7;
                        break;
                default:
                case CS8:
                        lData = LCR_BITS_8;
                        break;
                }
        }
        /* Change the Parity bit */
        if (cflag & PARENB) {
                if (cflag & PARODD) {
                        lParity = LCR_PAR_ODD;
                        dbg("%s - parity = odd", __func__);
                } else {
                        lParity = LCR_PAR_EVEN;
                        dbg("%s - parity = even", __func__);
                }

        } else {
                dbg("%s - parity = none", __func__);
        }

        if (cflag & CMSPAR)
                lParity = lParity | 0x20;

        /* Change the Stop bit */
        if (cflag & CSTOPB) {
                lStop = LCR_STOP_2;
                dbg("%s - stop bits = 2", __func__);
        } else {
                lStop = LCR_STOP_1;
                dbg("%s - stop bits = 1", __func__);
        }

        /* Update the LCR with the correct value */
        mos7840_port->shadowLCR &=
            ~(LCR_BITS_MASK | LCR_STOP_MASK | LCR_PAR_MASK);
        mos7840_port->shadowLCR |= (lData | lParity | lStop);

        dbg("mos7840_change_port_settings mos7840_port->shadowLCR is %x",
            mos7840_port->shadowLCR);
        /* Disable Interrupts */
        Data = 0x00;
        mos7840_set_uart_reg(port, INTERRUPT_ENABLE_REGISTER, Data);

        Data = 0x00;
        mos7840_set_uart_reg(port, FIFO_CONTROL_REGISTER, Data);

        Data = 0xcf;
        mos7840_set_uart_reg(port, FIFO_CONTROL_REGISTER, Data);

        /* Send the updated LCR value to the mos7840 */
        Data = mos7840_port->shadowLCR;

        mos7840_set_uart_reg(port, LINE_CONTROL_REGISTER, Data);

        Data = 0x00b;
        mos7840_port->shadowMCR = Data;
        mos7840_set_uart_reg(port, MODEM_CONTROL_REGISTER, Data);
        Data = 0x00b;
        mos7840_set_uart_reg(port, MODEM_CONTROL_REGISTER, Data);

        /* set up the MCR register and send it to the mos7840 */

        mos7840_port->shadowMCR = MCR_MASTER_IE;
        if (cflag & CBAUD)
                mos7840_port->shadowMCR |= (MCR_DTR | MCR_RTS);

        if (cflag & CRTSCTS)
                mos7840_port->shadowMCR |= (MCR_XON_ANY);
        else
                mos7840_port->shadowMCR &= ~(MCR_XON_ANY);

        Data = mos7840_port->shadowMCR;
        mos7840_set_uart_reg(port, MODEM_CONTROL_REGISTER, Data);

        /* Determine divisor based on baud rate */
        baud = tty_get_baud_rate(tty);

        if (!baud) {
                /* pick a default, any default... */
                dbg("%s", "Picked default baud...");
                baud = 9600;
        }

        dbg("%s - baud rate = %d", __func__, baud);
        status = mos7840_send_cmd_write_baud_rate(mos7840_port, baud);

        /* Enable Interrupts */
        Data = 0x0c;
        mos7840_set_uart_reg(port, INTERRUPT_ENABLE_REGISTER, Data);

        if (mos7840_port->read_urb_busy == false) {
                mos7840_port->read_urb->dev = serial->dev;
                mos7840_port->read_urb_busy = true;
                status = usb_submit_urb(mos7840_port->read_urb, GFP_ATOMIC);
                if (status) {
                        dbg("usb_submit_urb(read bulk) failed, status = %d",
                            status);
                        mos7840_port->read_urb_busy = false;
                }
        }
        wake_up(&mos7840_port->delta_msr_wait);
        mos7840_port->delta_msr_cond = 1;
        dbg("mos7840_change_port_settings mos7840_port->shadowLCR is End %x",
            mos7840_port->shadowLCR);

        return;
}

/*****************************************************************************
 * mos7840_set_termios
 *      this function is called by the tty driver when it wants to change
 *      the termios structure
 *****************************************************************************/

static void mos7840_set_termios(struct tty_struct *tty,
                                struct usb_serial_port *port,
                                struct ktermios *old_termios)
{
        int status;
        unsigned int cflag;
        struct usb_serial *serial;
        struct moschip_port *mos7840_port;
        dbg("mos7840_set_termios: START");
        if (mos7840_port_paranoia_check(port, __func__)) {
                dbg("%s", "Invalid port");
                return;
        }

        serial = port->serial;

        if (mos7840_serial_paranoia_check(serial, __func__)) {
                dbg("%s", "Invalid Serial");
                return;
        }

        mos7840_port = mos7840_get_port_private(port);

        if (mos7840_port == NULL)
                return;

        if (!mos7840_port->open) {
                dbg("%s - port not opened", __func__);
                return;
        }

        dbg("%s", "setting termios - ");

        cflag = tty->termios->c_cflag;

        dbg("%s - clfag %08x iflag %08x", __func__,
            tty->termios->c_cflag, RELEVANT_IFLAG(tty->termios->c_iflag));
        dbg("%s - old clfag %08x old iflag %08x", __func__,
            old_termios->c_cflag, RELEVANT_IFLAG(old_termios->c_iflag));
        dbg("%s - port %d", __func__, port->number);

        /* change the port settings to the new ones specified */

        mos7840_change_port_settings(tty, mos7840_port, old_termios);

        if (!mos7840_port->read_urb) {
                dbg("%s", "URB KILLED !!!!!");
                return;
        }

        if (mos7840_port->read_urb_busy == false) {
                mos7840_port->read_urb->dev = serial->dev;
                mos7840_port->read_urb_busy = true;
                status = usb_submit_urb(mos7840_port->read_urb, GFP_ATOMIC);
                if (status) {
                        dbg("usb_submit_urb(read bulk) failed, status = %d",
                            status);
                        mos7840_port->read_urb_busy = false;
                }
        }
        return;
}

/*****************************************************************************
 * mos7840_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 mos7840_get_lsr_info(struct tty_struct *tty,
                                unsigned int __user *value)
{
        int count;
        unsigned int result = 0;

        count = mos7840_chars_in_buffer(tty);
        if (count == 0) {
                dbg("%s -- Empty", __func__);
                result = TIOCSER_TEMT;
        }

        if (copy_to_user(value, &result, sizeof(int)))
                return -EFAULT;
        return 0;
}

/*****************************************************************************
 * mos7840_get_serial_info
 *      function to get information about serial port
 *****************************************************************************/

static int mos7840_get_serial_info(struct moschip_port *mos7840_port,
                                   struct serial_struct __user *retinfo)
{
        struct serial_struct tmp;

        if (mos7840_port == NULL)
                return -1;

        if (!retinfo)
                return -EFAULT;

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

        tmp.type = PORT_16550A;
        tmp.line = mos7840_port->port->serial->minor;
        tmp.port = mos7840_port->port->number;
        tmp.irq = 0;
        tmp.flags = ASYNC_SKIP_TEST | ASYNC_AUTO_IRQ;
        tmp.xmit_fifo_size = NUM_URBS * URB_TRANSFER_BUFFER_SIZE;
        tmp.baud_base = 9600;
        tmp.close_delay = 5 * HZ;
        tmp.closing_wait = 30 * HZ;

        if (copy_to_user(retinfo, &tmp, sizeof(*retinfo)))
                return -EFAULT;
        return 0;
}

/*****************************************************************************
 * SerialIoctl
 *      this function handles any ioctl calls to the driver
 *****************************************************************************/

static int mos7840_ioctl(struct tty_struct *tty, struct file *file,
                         unsigned int cmd, unsigned long arg)
{
        struct usb_serial_port *port = tty->driver_data;
        void __user *argp = (void __user *)arg;
        struct moschip_port *mos7840_port;

        struct async_icount cnow;
        struct async_icount cprev;
        struct serial_icounter_struct icount;

        if (mos7840_port_paranoia_check(port, __func__)) {
                dbg("%s", "Invalid port");
                return -1;
        }

        mos7840_port = mos7840_get_port_private(port);

        if (mos7840_port == NULL)
                return -1;

        dbg("%s - port %d, cmd = 0x%x", __func__, port->number, cmd);

        switch (cmd) {
                /* return number of bytes available */

        case TIOCSERGETLSR:
                dbg("%s (%d) TIOCSERGETLSR", __func__, port->number);
                return mos7840_get_lsr_info(tty, argp);
                return 0;

        case TIOCGSERIAL:
                dbg("%s (%d) TIOCGSERIAL", __func__, port->number);
                return mos7840_get_serial_info(mos7840_port, argp);

        case TIOCSSERIAL:
                dbg("%s (%d) TIOCSSERIAL", __func__, port->number);
                break;

        case TIOCMIWAIT:
                dbg("%s (%d) TIOCMIWAIT", __func__, port->number);
                cprev = mos7840_port->icount;
                while (1) {
                        /* interruptible_sleep_on(&mos7840_port->delta_msr_wait); */
                        mos7840_port->delta_msr_cond = 0;
                        wait_event_interruptible(mos7840_port->delta_msr_wait,
                                                 (mos7840_port->
                                                  delta_msr_cond == 1));

                        /* see if a signal did it */
                        if (signal_pending(current))
                                return -ERESTARTSYS;
                        cnow = mos7840_port->icount;
                        smp_rmb();
                        if (cnow.rng == cprev.rng && cnow.dsr == cprev.dsr &&
                            cnow.dcd == cprev.dcd && cnow.cts == cprev.cts)
                                return -EIO;    /* no change => error */
                        if (((arg & TIOCM_RNG) && (cnow.rng != cprev.rng)) ||
                            ((arg & TIOCM_DSR) && (cnow.dsr != cprev.dsr)) ||
                            ((arg & TIOCM_CD) && (cnow.dcd != cprev.dcd)) ||
                            ((arg & TIOCM_CTS) && (cnow.cts != cprev.cts))) {
                                return 0;
                        }
                        cprev = cnow;
                }
                /* NOTREACHED */
                break;

        case TIOCGICOUNT:
                cnow = mos7840_port->icount;
                smp_rmb();
                icount.cts = cnow.cts;
                icount.dsr = cnow.dsr;
                icount.rng = cnow.rng;
                icount.dcd = cnow.dcd;
                icount.rx = cnow.rx;
                icount.tx = cnow.tx;
                icount.frame = cnow.frame;
                icount.overrun = cnow.overrun;
                icount.parity = cnow.parity;
                icount.brk = cnow.brk;
                icount.buf_overrun = cnow.buf_overrun;

                dbg("%s (%d) TIOCGICOUNT RX=%d, TX=%d", __func__,
                    port->number, icount.rx, icount.tx);
                if (copy_to_user(argp, &icount, sizeof(icount)))
                        return -EFAULT;
                return 0;
        default:
                break;
        }
        return -ENOIOCTLCMD;
}

static int mos7840_calc_num_ports(struct usb_serial *serial)
{
        int mos7840_num_ports = 0;

        dbg("numberofendpoints: cur %d, alt %d",
            (int)serial->interface->cur_altsetting->desc.bNumEndpoints,
            (int)serial->interface->altsetting->desc.bNumEndpoints);
        if (serial->interface->cur_altsetting->desc.bNumEndpoints == 5) {
                mos7840_num_ports = serial->num_ports = 2;
        } else if (serial->interface->cur_altsetting->desc.bNumEndpoints == 9) {
                serial->num_bulk_in = 4;
                serial->num_bulk_out = 4;
                mos7840_num_ports = serial->num_ports = 4;
        }
        dbg ("mos7840_num_ports = %d", mos7840_num_ports);
        return mos7840_num_ports;
}

/****************************************************************************
 * mos7840_startup
 ****************************************************************************/

static int mos7840_startup(struct usb_serial *serial)
{
        struct moschip_port *mos7840_port;
        struct usb_device *dev;
        int i, status;

        __u16 Data;
        dbg("%s", "mos7840_startup :Entering..........");

        if (!serial) {
                dbg("%s", "Invalid Handler");
                return -1;
        }

        dev = serial->dev;

        dbg("%s", "Entering...");
        dbg ("mos7840_startup: serial = %p", serial);

        /* we set up the pointers to the endpoints in the mos7840_open *
         * function, as the structures aren't created yet.             */

        /* set up port private structures */
        for (i = 0; i < serial->num_ports; ++i) {
                dbg ("mos7840_startup: configuring port %d............", i);
                mos7840_port = kzalloc(sizeof(struct moschip_port), GFP_KERNEL);
                if (mos7840_port == NULL) {
                        dev_err(&dev->dev, "%s - Out of memory\n", __func__);
                        status = -ENOMEM;
                        i--; /* don't follow NULL pointer cleaning up */
                        goto error;
                }

                /* Initialize all port interrupt end point to port 0 int
                 * endpoint. Our device has only one interrupt end point
                 * common to all port */

                mos7840_port->port = serial->port[i];
                mos7840_set_port_private(serial->port[i], mos7840_port);
                spin_lock_init(&mos7840_port->pool_lock);

                /* minor is not initialised until later by
                 * usb-serial.c:get_free_serial() and cannot therefore be used
                 * to index device instances */
                mos7840_port->port_num = i + 1;
                dbg ("serial->port[i]->number = %d", serial->port[i]->number);
                dbg ("serial->port[i]->serial->minor = %d", serial->port[i]->serial->minor);
                dbg ("mos7840_port->port_num = %d", mos7840_port->port_num);
                dbg ("serial->minor = %d", serial->minor);

                if (mos7840_port->port_num == 1) {
                        mos7840_port->SpRegOffset = 0x0;
                        mos7840_port->ControlRegOffset = 0x1;
                        mos7840_port->DcrRegOffset = 0x4;
                } else if ((mos7840_port->port_num == 2)
                           && (serial->num_ports == 4)) {
                        mos7840_port->SpRegOffset = 0x8;
                        mos7840_port->ControlRegOffset = 0x9;
                        mos7840_port->DcrRegOffset = 0x16;
                } else if ((mos7840_port->port_num == 2)
                           && (serial->num_ports == 2)) {
                        mos7840_port->SpRegOffset = 0xa;
                        mos7840_port->ControlRegOffset = 0xb;
                        mos7840_port->DcrRegOffset = 0x19;
                } else if ((mos7840_port->port_num == 3)
                           && (serial->num_ports == 4)) {
                        mos7840_port->SpRegOffset = 0xa;
                        mos7840_port->ControlRegOffset = 0xb;
                        mos7840_port->DcrRegOffset = 0x19;
                } else if ((mos7840_port->port_num == 4)
                           && (serial->num_ports == 4)) {
                        mos7840_port->SpRegOffset = 0xc;
                        mos7840_port->ControlRegOffset = 0xd;
                        mos7840_port->DcrRegOffset = 0x1c;
                }
                mos7840_dump_serial_port(mos7840_port);
                mos7840_set_port_private(serial->port[i], mos7840_port);

                /* enable rx_disable bit in control register */
                status = mos7840_get_reg_sync(serial->port[i],
                                 mos7840_port->ControlRegOffset, &Data);
                if (status < 0) {
                        dbg("Reading ControlReg failed status-0x%x", status);
                        break;
                } else
                        dbg("ControlReg Reading success val is %x, status%d",
                            Data, status);
                Data |= 0x08;   /* setting driver done bit */
                Data |= 0x04;   /* sp1_bit to have cts change reflect in
                                   modem status reg */

                /* Data |= 0x20; //rx_disable bit */
                status = mos7840_set_reg_sync(serial->port[i],
                                         mos7840_port->ControlRegOffset, Data);
                if (status < 0) {
                        dbg("Writing ControlReg failed(rx_disable) status-0x%x", status);
                        break;
                } else
                        dbg("ControlReg Writing success(rx_disable) status%d",
                            status);

                /* Write default values in DCR (i.e 0x01 in DCR0, 0x05 in DCR2
                   and 0x24 in DCR3 */
                Data = 0x01;
                status = mos7840_set_reg_sync(serial->port[i],
                         (__u16) (mos7840_port->DcrRegOffset + 0), Data);
                if (status < 0) {
                        dbg("Writing DCR0 failed status-0x%x", status);
                        break;
                } else
                        dbg("DCR0 Writing success status%d", status);

                Data = 0x05;
                status = mos7840_set_reg_sync(serial->port[i],
                         (__u16) (mos7840_port->DcrRegOffset + 1), Data);
                if (status < 0) {
                        dbg("Writing DCR1 failed status-0x%x", status);
                        break;
                } else
                        dbg("DCR1 Writing success status%d", status);

                Data = 0x24;
                status = mos7840_set_reg_sync(serial->port[i],
                         (__u16) (mos7840_port->DcrRegOffset + 2), Data);
                if (status < 0) {
                        dbg("Writing DCR2 failed status-0x%x", status);
                        break;
                } else
                        dbg("DCR2 Writing success status%d", status);

                /* write values in clkstart0x0 and clkmulti 0x20 */
                Data = 0x0;
                status = mos7840_set_reg_sync(serial->port[i],
                                         CLK_START_VALUE_REGISTER, Data);
                if (status < 0) {
                        dbg("Writing CLK_START_VALUE_REGISTER failed status-0x%x", status);
                        break;
                } else
                        dbg("CLK_START_VALUE_REGISTER Writing success status%d", status);

                Data = 0x20;
                status = mos7840_set_reg_sync(serial->port[i],
                                        CLK_MULTI_REGISTER, Data);
                if (status < 0) {
                        dbg("Writing CLK_MULTI_REGISTER failed status-0x%x",
                            status);
                        goto error;
                } else
                        dbg("CLK_MULTI_REGISTER Writing success status%d",
                            status);

                /* write value 0x0 to scratchpad register */
                Data = 0x00;
                status = mos7840_set_uart_reg(serial->port[i],
                                                SCRATCH_PAD_REGISTER, Data);
                if (status < 0) {
                        dbg("Writing SCRATCH_PAD_REGISTER failed status-0x%x",
                            status);
                        break;
                } else
                        dbg("SCRATCH_PAD_REGISTER Writing success status%d",
                            status);

                /* Zero Length flag register */
                if ((mos7840_port->port_num != 1)
                    && (serial->num_ports == 2)) {

                        Data = 0xff;
                        status = mos7840_set_reg_sync(serial->port[i],
                                      (__u16) (ZLP_REG1 +
                                      ((__u16)mos7840_port->port_num)), Data);
                        dbg("ZLIP offset %x",
                            (__u16) (ZLP_REG1 +
                                        ((__u16) mos7840_port->port_num)));
                        if (status < 0) {
                                dbg("Writing ZLP_REG%d failed status-0x%x",
                                    i + 2, status);
                                break;
                        } else
                                dbg("ZLP_REG%d Writing success status%d",
                                    i + 2, status);
                } else {
                        Data = 0xff;
                        status = mos7840_set_reg_sync(serial->port[i],
                              (__u16) (ZLP_REG1 +
                              ((__u16)mos7840_port->port_num) - 0x1), Data);
                        dbg("ZLIP offset %x",
                            (__u16) (ZLP_REG1 +
                                     ((__u16) mos7840_port->port_num) - 0x1));
                        if (status < 0) {
                                dbg("Writing ZLP_REG%d failed status-0x%x",
                                    i + 1, status);
                                break;
                        } else
                                dbg("ZLP_REG%d Writing success status%d",
                                    i + 1, status);

                }
                mos7840_port->control_urb = usb_alloc_urb(0, GFP_KERNEL);
                mos7840_port->ctrl_buf = kmalloc(16, GFP_KERNEL);
                mos7840_port->dr = kmalloc(sizeof(struct usb_ctrlrequest),
                                                                GFP_KERNEL);
                if (!mos7840_port->control_urb || !mos7840_port->ctrl_buf ||
                                                        !mos7840_port->dr) {
                        status = -ENOMEM;
                        goto error;
                }
        }
        dbg ("mos7840_startup: all ports configured...........");

        /* Zero Length flag enable */
        Data = 0x0f;
        status = mos7840_set_reg_sync(serial->port[0], ZLP_REG5, Data);
        if (status < 0) {
                dbg("Writing ZLP_REG5 failed status-0x%x", status);
                goto error;
        } else
                dbg("ZLP_REG5 Writing success status%d", status);

        /* setting configuration feature to one */
        usb_control_msg(serial->dev, usb_sndctrlpipe(serial->dev, 0),
                        (__u8) 0x03, 0x00, 0x01, 0x00, NULL, 0x00, 5 * HZ);
        return 0;
error:
        for (/* nothing */; i >= 0; i--) {
                mos7840_port = mos7840_get_port_private(serial->port[i]);

                kfree(mos7840_port->dr);
                kfree(mos7840_port->ctrl_buf);
                usb_free_urb(mos7840_port->control_urb);
                kfree(mos7840_port);
                serial->port[i] = NULL;
        }
        return status;
}

/****************************************************************************
 * mos7840_disconnect
 *      This function is called whenever the device is removed from the usb bus.
 ****************************************************************************/

static void mos7840_disconnect(struct usb_serial *serial)
{
        int i;
        unsigned long flags;
        struct moschip_port *mos7840_port;
        dbg("%s", " disconnect :entering..........");

        if (!serial) {
                dbg("%s", "Invalid Handler");
                return;
        }

        /* check for the ports to be closed,close the ports and disconnect */

        /* free private structure allocated for serial port  *
         * stop reads and writes on all ports                */

        for (i = 0; i < serial->num_ports; ++i) {
                mos7840_port = mos7840_get_port_private(serial->port[i]);
                dbg ("mos7840_port %d = %p", i, mos7840_port);
                if (mos7840_port) {
                        spin_lock_irqsave(&mos7840_port->pool_lock, flags);
                        mos7840_port->zombie = 1;
                        spin_unlock_irqrestore(&mos7840_port->pool_lock, flags);
                        usb_kill_urb(mos7840_port->control_urb);
                }
        }

        dbg("%s", "Thank u :: ");

}

/****************************************************************************
 * mos7840_release
 *      This function is called when the usb_serial structure is freed.
 ****************************************************************************/

static void mos7840_release(struct usb_serial *serial)
{
        int i;
        struct moschip_port *mos7840_port;
        dbg("%s", " release :entering..........");

        if (!serial) {
                dbg("%s", "Invalid Handler");
                return;
        }

        /* check for the ports to be closed,close the ports and disconnect */

        /* free private structure allocated for serial port  *
         * stop reads and writes on all ports                */

        for (i = 0; i < serial->num_ports; ++i) {
                mos7840_port = mos7840_get_port_private(serial->port[i]);
                dbg("mos7840_port %d = %p", i, mos7840_port);
                if (mos7840_port) {
                        kfree(mos7840_port->ctrl_buf);
                        kfree(mos7840_port->dr);
                        kfree(mos7840_port);
                }
        }

        dbg("%s", "Thank u :: ");

}

static struct usb_driver io_driver = {
        .name = "mos7840",
        .probe = usb_serial_probe,
        .disconnect = usb_serial_disconnect,
        .id_table = moschip_id_table_combined,
        .no_dynamic_id = 1,
};

static struct usb_serial_driver moschip7840_4port_device = {
        .driver = {
                   .owner = THIS_MODULE,
                   .name = "mos7840",
                   },
        .description = DRIVER_DESC,
        .usb_driver = &io_driver,
        .id_table = moschip_port_id_table,
        .num_ports = 4,
        .open = mos7840_open,
        .close = mos7840_close,
        .write = mos7840_write,
        .write_room = mos7840_write_room,
        .chars_in_buffer = mos7840_chars_in_buffer,
        .throttle = mos7840_throttle,
        .unthrottle = mos7840_unthrottle,
        .calc_num_ports = mos7840_calc_num_ports,
#ifdef MCSSerialProbe
        .probe = mos7840_serial_probe,
#endif
        .ioctl = mos7840_ioctl,
        .set_termios = mos7840_set_termios,
        .break_ctl = mos7840_break,
        .tiocmget = mos7840_tiocmget,
        .tiocmset = mos7840_tiocmset,
        .attach = mos7840_startup,
        .disconnect = mos7840_disconnect,
        .release = mos7840_release,
        .read_bulk_callback = mos7840_bulk_in_callback,
        .read_int_callback = mos7840_interrupt_callback,
};

/****************************************************************************
 * moschip7840_init
 *      This is called by the module subsystem, or on startup to initialize us
 ****************************************************************************/
static int __init moschip7840_init(void)
{
        int retval;

        dbg("%s", " mos7840_init :entering..........");

        /* Register with the usb serial */
        retval = usb_serial_register(&moschip7840_4port_device);

        if (retval)
                goto failed_port_device_register;

        dbg("%s", "Entering...");
        printk(KERN_INFO KBUILD_MODNAME ": " DRIVER_VERSION ":"
               DRIVER_DESC "\n");

        /* Register with the usb */
        retval = usb_register(&io_driver);
        if (retval == 0) {
                dbg("%s", "Leaving...");
                return 0;
        }
        usb_serial_deregister(&moschip7840_4port_device);
failed_port_device_register:
        return retval;
}

/****************************************************************************
 * moschip7840_exit
 *      Called when the driver is about to be unloaded.
 ****************************************************************************/
static void __exit moschip7840_exit(void)
{

        dbg("%s", " mos7840_exit :entering..........");

        usb_deregister(&io_driver);

        usb_serial_deregister(&moschip7840_4port_device);

        dbg("%s", "Entering...");
}

module_init(moschip7840_init);
module_exit(moschip7840_exit);

/* Module information */
MODULE_DESCRIPTION(DRIVER_DESC);
MODULE_LICENSE("GPL");

module_param(debug, bool, S_IRUGO | S_IWUSR);
MODULE_PARM_DESC(debug, "Debug enabled or not");