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/*
 * Prolific PL2303 USB to serial adaptor driver
 *
 * Copyright (C) 2001-2003 Greg Kroah-Hartman (greg@kroah.com)
 * Copyright (C) 2003 IBM Corp.
 *
 * Original driver for 2.2.x by anonymous
 *
 *      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.
 *
 * See Documentation/usb/usb-serial.txt for more information on using this driver
 *
 * 2002_Mar_26 gkh
 *      allowed driver to work properly if there is no tty assigned to a port
 *      (this happens for serial console devices.)
 *
 * 2001_Oct_06 gkh
 *      Added RTS and DTR line control.  Thanks to joe@bndlg.de for parts of it.
 *
 * 2001_Sep_19 gkh
 *      Added break support.
 *
 * 2001_Aug_30 gkh
 *      fixed oops in write_bulk_callback.
 *
 * 2001_Aug_28 gkh
 *      reworked buffer logic to be like other usb-serial drivers.  Hopefully
 *      removing some reported problems.
 *
 * 2001_Jun_06 gkh
 *      finished porting to 2.4 format.
 *
 */

#include <linuxcomp.h>

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

#ifdef CONFIG_USB_SERIAL_DEBUG
        static int debug = 1;
#else
        static int debug;
#endif

#include "usb-serial.h"
#include "pl2303.h"

/*
 * Version Information
 */
#define DRIVER_VERSION "v0.10"
#define DRIVER_DESC "Prolific PL2303 USB to serial adaptor driver"



static struct usb_device_id id_table [] = {
        { USB_DEVICE(PL2303_VENDOR_ID, PL2303_PRODUCT_ID) },
        { USB_DEVICE(PL2303_VENDOR_ID, PL2303_PRODUCT_ID_RSAQ2) },
        { USB_DEVICE(IODATA_VENDOR_ID, IODATA_PRODUCT_ID) },
        { USB_DEVICE(ATEN_VENDOR_ID, ATEN_PRODUCT_ID) },
        { USB_DEVICE(ELCOM_VENDOR_ID, ELCOM_PRODUCT_ID) },
        { USB_DEVICE(ITEGNO_VENDOR_ID, ITEGNO_PRODUCT_ID) },
        { USB_DEVICE(MA620_VENDOR_ID, MA620_PRODUCT_ID) },
        { USB_DEVICE(RATOC_VENDOR_ID, RATOC_PRODUCT_ID) },
        { USB_DEVICE(TRIPP_VENDOR_ID, TRIPP_PRODUCT_ID) },
        { USB_DEVICE(RADIOSHACK_VENDOR_ID, RADIOSHACK_PRODUCT_ID) },
        { USB_DEVICE(DCU10_VENDOR_ID, DCU10_PRODUCT_ID) },
        { }                                     /* Terminating entry */
};

MODULE_DEVICE_TABLE (usb, id_table);

static struct usb_driver pl2303_driver = {
        .owner =        THIS_MODULE,
        .name =         "pl2303",
        .probe =        usb_serial_probe,
        .disconnect =   usb_serial_disconnect,
        .id_table =     id_table,
};

#define SET_LINE_REQUEST_TYPE           0x21
#define SET_LINE_REQUEST                0x20

#define SET_CONTROL_REQUEST_TYPE        0x21
#define SET_CONTROL_REQUEST             0x22
#define CONTROL_DTR                     0x01
#define CONTROL_RTS                     0x02

#define BREAK_REQUEST_TYPE              0x21
#define BREAK_REQUEST                   0x23   
#define BREAK_ON                        0xffff
#define BREAK_OFF                       0x0000

#define GET_LINE_REQUEST_TYPE           0xa1
#define GET_LINE_REQUEST                0x21

#define VENDOR_WRITE_REQUEST_TYPE       0x40
#define VENDOR_WRITE_REQUEST            0x01

#define VENDOR_READ_REQUEST_TYPE        0xc0
#define VENDOR_READ_REQUEST             0x01

#define UART_STATE                      0x08
#define UART_DCD                        0x01
#define UART_DSR                        0x02
#define UART_BREAK_ERROR                0x04
#define UART_RING                       0x08
#define UART_FRAME_ERROR                0x10
#define UART_PARITY_ERROR               0x20
#define UART_OVERRUN_ERROR              0x40
#define UART_CTS                        0x80

/* function prototypes for a PL2303 serial converter */
static int pl2303_open (struct usb_serial_port *port, struct file *filp);
static void pl2303_close (struct usb_serial_port *port, struct file *filp);
static void pl2303_set_termios (struct usb_serial_port *port,
                                struct termios *old);
static int pl2303_ioctl (struct usb_serial_port *port, struct file *file,
                         unsigned int cmd, unsigned long arg);
static void pl2303_read_int_callback (struct urb *urb, struct pt_regs *regs);
static void pl2303_read_bulk_callback (struct urb *urb, struct pt_regs *regs);
static void pl2303_write_bulk_callback (struct urb *urb, struct pt_regs *regs);
static int pl2303_write (struct usb_serial_port *port, int from_user,
                         const unsigned char *buf, int count);
static void pl2303_break_ctl(struct usb_serial_port *port,int break_state);
static int pl2303_tiocmget (struct usb_serial_port *port, struct file *file);
static int pl2303_tiocmset (struct usb_serial_port *port, struct file *file,
                            unsigned int set, unsigned int clear);
static int pl2303_startup (struct usb_serial *serial);
static void pl2303_shutdown (struct usb_serial *serial);


/* All of the device info needed for the PL2303 SIO serial converter */
static struct usb_serial_device_type pl2303_device = {
        .owner =                THIS_MODULE,
        .name =                 "PL-2303",
        .id_table =             id_table,
        .num_interrupt_in =     NUM_DONT_CARE,
        .num_bulk_in =          1,
        .num_bulk_out =         1,
        .num_ports =            1,
        .open =                 pl2303_open,
        .close =                pl2303_close,
        .write =                pl2303_write,
        .ioctl =                pl2303_ioctl,
        .break_ctl =            pl2303_break_ctl,
        .set_termios =          pl2303_set_termios,
        .tiocmget =             pl2303_tiocmget,
        .tiocmset =             pl2303_tiocmset,
        .read_bulk_callback =   pl2303_read_bulk_callback,
        .read_int_callback =    pl2303_read_int_callback,
        .write_bulk_callback =  pl2303_write_bulk_callback,
        .attach =               pl2303_startup,
        .shutdown =             pl2303_shutdown,
};

struct pl2303_private {
        spinlock_t lock;
        u8 line_control;
        u8 line_status;
        u8 termios_initialized;
};


static int pl2303_startup (struct usb_serial *serial)
{
        struct pl2303_private *priv;
        int i;

        for (i = 0; i < serial->num_ports; ++i) {
                priv = kmalloc (sizeof (struct pl2303_private), GFP_KERNEL);
                if (!priv)
                        return -ENOMEM;
                memset (priv, 0x00, sizeof (struct pl2303_private));
                spin_lock_init(&priv->lock);
                usb_set_serial_port_data(serial->port[i], priv);
        }
        return 0;
}

static int set_control_lines (struct usb_device *dev, u8 value)
{
        int retval;
       
        retval = usb_control_msg (dev, usb_sndctrlpipe (dev, 0),
                                  SET_CONTROL_REQUEST, SET_CONTROL_REQUEST_TYPE,
                                  value, 0, NULL, 0, 100);
        dbg("%s - value = %d, retval = %d", __FUNCTION__, value, retval);
        return retval;
}

static int pl2303_write (struct usb_serial_port *port, int from_user,  const unsigned char *buf, int count)
{
        int result;

        dbg("%s - port %d, %d bytes", __FUNCTION__, port->number, count);

        if (port->write_urb->status == -EINPROGRESS) {
                dbg("%s - already writing", __FUNCTION__);
                return 0;
        }

        count = (count > port->bulk_out_size) ? port->bulk_out_size : count;
        if (from_user) {
                if (copy_from_user (port->write_urb->transfer_buffer, buf, count))
                        return -EFAULT;
        } else {
                memcpy (port->write_urb->transfer_buffer, buf, count);
        }
       
        usb_serial_debug_data (__FILE__, __FUNCTION__, count, port->write_urb->transfer_buffer);

        port->write_urb->transfer_buffer_length = count;
        port->write_urb->dev = port->serial->dev;
        result = usb_submit_urb (port->write_urb, GFP_ATOMIC);
        if (result)
                dev_err(&port->dev, "%s - failed submitting write urb, error %d\n", __FUNCTION__, result);
        else
                result = count;

        return result;
}



static void pl2303_set_termios (struct usb_serial_port *port, struct termios *old_termios)
{
        struct usb_serial *serial = port->serial;
        struct pl2303_private *priv = usb_get_serial_port_data(port);
        unsigned long flags;
        unsigned int cflag;
        unsigned char *buf;
        int baud;
        int i;
        u8 control;

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

        if ((!port->tty) || (!port->tty->termios)) {
                dbg("%s - no tty structures", __FUNCTION__);
                return;
        }

  spin_lock_irqsave(&priv->lock, flags);

        if (!priv->termios_initialized) {
    printk(KERN_INFO "@####### termios initializated\n");
                *(port->tty->termios) = tty_std_termios;
    port->tty->termios->c_cflag = B38400 | CS8 | CREAD | HUPCL | CLOCAL;
                priv->termios_initialized = 1;
        }

        spin_unlock_irqrestore(&priv->lock, flags);

        cflag = port->tty->termios->c_cflag;
        /* check that they really want us to change something */
        if (old_termios) {
                if ((cflag == old_termios->c_cflag) &&
                    (RELEVANT_IFLAG(port->tty->termios->c_iflag) == RELEVANT_IFLAG(old_termios->c_iflag))) {
                    dbg("%s - nothing to change...", __FUNCTION__);
                    return;
                }
        }

        buf = kmalloc (7, GFP_KERNEL);
        if (!buf) {
                dev_err(&port->dev, "%s - out of memory.\n", __FUNCTION__);
                return;
        }
        memset (buf, 0x00, 0x07);
       
        i = usb_control_msg (serial->dev, usb_rcvctrlpipe (serial->dev, 0),
                             GET_LINE_REQUEST, GET_LINE_REQUEST_TYPE,
                             0, 0, buf, 7, 100);
        dbg ("0xa1:0x21:0:0  %d - %x %x %x %x %x %x %x", i,
             buf[0], buf[1], buf[2], buf[3], buf[4], buf[5], buf[6]);


        if (cflag & CSIZE) {
                switch (cflag & CSIZE) {
                        case CS5:       buf[6] = 5;     break;
                        case CS6:       buf[6] = 6;     break;
                        case CS7:       buf[6] = 7;     break;
                        default:
                        case CS8:       buf[6] = 8;     break;
                }
                dbg("%s - data bits = %d", __FUNCTION__, buf[6]);
        }

        baud = 0;
        switch (cflag & CBAUD) {
                case B0:        baud = 0;       break;
                case B75:       baud = 75;      break;
                case B150:      baud = 150;     break;
                case B300:      baud = 300;     break;
                case B600:      baud = 600;     break;
                case B1200:     baud = 1200;    break;
                case B1800:     baud = 1800;    break;
                case B2400:     baud = 2400;    break;
                case B4800:     baud = 4800;    break;
                case B9600:     baud = 9600;    break;
                case B19200:    baud = 19200;   break;
                case B38400:    baud = 38400;   break;
                case B57600:    baud = 57600;   break;
                case B115200:   baud = 115200;  break;
                case B230400:   baud = 230400;  break;
                case B460800:   baud = 460800;  break;
                default:
                        dev_err(&port->dev, "pl2303 driver does not support the baudrate requested (fix it)\n");
                        break;
        }
        dbg("%s - baud = %d", __FUNCTION__, baud);
        if (baud) {
                buf[0] = baud & 0xff;
                buf[1] = (baud >> 8) & 0xff;
                buf[2] = (baud >> 16) & 0xff;
                buf[3] = (baud >> 24) & 0xff;
        }

        /* For reference buf[4]=0 is 1 stop bits */
        /* For reference buf[4]=1 is 1.5 stop bits */
        /* For reference buf[4]=2 is 2 stop bits */
        if (cflag & CSTOPB) {
                buf[4] = 2;
                dbg("%s - stop bits = 2", __FUNCTION__);
        } else {
                buf[4] = 0;
                dbg("%s - stop bits = 1", __FUNCTION__);
        }

        if (cflag & PARENB) {
                /* For reference buf[5]=0 is none parity */
                /* For reference buf[5]=1 is odd parity */
                /* For reference buf[5]=2 is even parity */
                /* For reference buf[5]=3 is mark parity */
                /* For reference buf[5]=4 is space parity */
                if (cflag & PARODD) {
                        buf[5] = 1;
                        dbg("%s - parity = odd", __FUNCTION__);
                } else {
                        buf[5] = 2;
                        dbg("%s - parity = even", __FUNCTION__);
                }
        } else {
                buf[5] = 0;
                dbg("%s - parity = none", __FUNCTION__);
        }

        i = usb_control_msg (serial->dev, usb_sndctrlpipe (serial->dev, 0),
                             SET_LINE_REQUEST, SET_LINE_REQUEST_TYPE,
                             0, 0, buf, 7, 100);
        dbg ("0x21:0x20:0:0  %d", i);

        /* change control lines if we are switching to or from B0 */
        spin_lock_irqsave(&priv->lock, flags);
        control = priv->line_control;
        if ((cflag & CBAUD) == B0)
                priv->line_control &= ~(CONTROL_DTR | CONTROL_RTS);
        else
                priv->line_control |= (CONTROL_DTR | CONTROL_RTS);
        if (control != priv->line_control) {
                control = priv->line_control;
                spin_unlock_irqrestore(&priv->lock, flags);
                set_control_lines(serial->dev, control);
        } else {
                spin_unlock_irqrestore(&priv->lock, flags);
        }
       
        buf[0] = buf[1] = buf[2] = buf[3] = buf[4] = buf[5] = buf[6] = 0;

        i = usb_control_msg (serial->dev, usb_rcvctrlpipe (serial->dev, 0),
                             GET_LINE_REQUEST, GET_LINE_REQUEST_TYPE,
                             0, 0, buf, 7, 100);
        dbg ("0xa1:0x21:0:0  %d - %x %x %x %x %x %x %x", i,
             buf[0], buf[1], buf[2], buf[3], buf[4], buf[5], buf[6]);

        if (cflag & CRTSCTS) {
                i = usb_control_msg (serial->dev, usb_sndctrlpipe (serial->dev, 0),
                                     VENDOR_WRITE_REQUEST, VENDOR_WRITE_REQUEST_TYPE,
                                     0x0, 0x41, NULL, 0, 100);
                dbg ("0x40:0x1:0x0:0x41  %d", i);
        }

        kfree (buf);
}      


static int pl2303_open (struct usb_serial_port *port, struct file *filp)
{
        struct termios tmp_termios;
        struct usb_serial *serial = port->serial;
        unsigned char buf[10];
        int result;

        if (port_paranoia_check (port, __FUNCTION__))
                return -ENODEV;
               
        dbg("%s -  port %d", __FUNCTION__, port->number);

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

#define FISH(a,b,c,d)                                                           \
        result=usb_control_msg(serial->dev, usb_rcvctrlpipe(serial->dev,0),     \
                               b, a, c, d, buf, 1, 100);                        \
        dbg("0x%x:0x%x:0x%x:0x%x  %d - %x",a,b,c,d,result,buf[0]);

#define SOUP(a,b,c,d)                                                           \
        result=usb_control_msg(serial->dev, usb_sndctrlpipe(serial->dev,0),     \
                               b, a, c, d, NULL, 0, 100);                       \
        dbg("0x%x:0x%x:0x%x:0x%x  %d",a,b,c,d,result);

        FISH (VENDOR_READ_REQUEST_TYPE, VENDOR_READ_REQUEST, 0x8484, 0);
        SOUP (VENDOR_WRITE_REQUEST_TYPE, VENDOR_WRITE_REQUEST, 0x0404, 0);
        FISH (VENDOR_READ_REQUEST_TYPE, VENDOR_READ_REQUEST, 0x8484, 0);
        FISH (VENDOR_READ_REQUEST_TYPE, VENDOR_READ_REQUEST, 0x8383, 0);
        FISH (VENDOR_READ_REQUEST_TYPE, VENDOR_READ_REQUEST, 0x8484, 0);
        SOUP (VENDOR_WRITE_REQUEST_TYPE, VENDOR_WRITE_REQUEST, 0x0404, 1);
        FISH (VENDOR_READ_REQUEST_TYPE, VENDOR_READ_REQUEST, 0x8484, 0);
        FISH (VENDOR_READ_REQUEST_TYPE, VENDOR_READ_REQUEST, 0x8383, 0);

        /* Setup termios */
        if (port->tty) {
    printk(KERN_INFO "#####@ set termios");
                pl2303_set_termios (port, &tmp_termios);
        }

        //FIXME: need to assert RTS and DTR if CRTSCTS off

        dbg("%s - submitting read urb", __FUNCTION__);
        port->read_urb->dev = serial->dev;
        result = usb_submit_urb (port->read_urb, GFP_KERNEL);
        if (result) {
                dev_err(&port->dev, "%s - failed submitting read urb, error %d\n", __FUNCTION__, result);
                pl2303_close (port, NULL);
                return -EPROTO;
        }

        dbg("%s - submitting interrupt urb", __FUNCTION__);
        port->interrupt_in_urb->dev = serial->dev;
        result = usb_submit_urb (port->interrupt_in_urb, GFP_KERNEL);
        if (result) {
                dev_err(&port->dev, "%s - failed submitting interrupt urb, error %d\n", __FUNCTION__, result);
                pl2303_close (port, NULL);
                return -EPROTO;
        }
        return 0;
}


static void pl2303_close (struct usb_serial_port *port, struct file *filp)
{
        struct usb_serial *serial;
        struct pl2303_private *priv;
        unsigned long flags;
        unsigned int c_cflag;
        int result;

        if (port_paranoia_check (port, __FUNCTION__))
                return;
        serial = get_usb_serial (port, __FUNCTION__);
        if (!serial)
                return;
       
        dbg("%s - port %d", __FUNCTION__, port->number);

        /* shutdown our urbs */
        dbg("%s - shutting down urbs", __FUNCTION__);
        result = usb_unlink_urb (port->write_urb);
        if (result)
                dbg("%s - usb_unlink_urb (write_urb)"
                    " failed with reason: %d", __FUNCTION__,
                     result);

        result = usb_unlink_urb (port->read_urb);
        if (result)
                dbg("%s - usb_unlink_urb (read_urb) "
                    "failed with reason: %d", __FUNCTION__,
                     result);

        result = usb_unlink_urb (port->interrupt_in_urb);
        if (result)
                dbg("%s - usb_unlink_urb (interrupt_in_urb)"
                    " failed with reason: %d", __FUNCTION__,
                     result);

        if (port->tty) {
                c_cflag = port->tty->termios->c_cflag;
                if (c_cflag & HUPCL) {
                        /* drop DTR and RTS */
                        priv = usb_get_serial_port_data(port);
                        spin_lock_irqsave(&priv->lock, flags);
                        priv->line_control = 0;
                        spin_unlock_irqrestore (&priv->lock, flags);
                        set_control_lines (port->serial->dev, 0);
                }
        }

}

static int pl2303_tiocmset (struct usb_serial_port *port, struct file *file,
                            unsigned int set, unsigned int clear)
{
        struct pl2303_private *priv = usb_get_serial_port_data(port);
        unsigned long flags;
        u8 control;

        spin_lock_irqsave (&priv->lock, flags);
        if (set & TIOCM_RTS)
                priv->line_control |= CONTROL_RTS;
        if (set & TIOCM_DTR)
                priv->line_control |= CONTROL_DTR;
        if (clear & TIOCM_RTS)
                priv->line_control &= ~CONTROL_RTS;
        if (clear & TIOCM_DTR)
                priv->line_control &= ~CONTROL_DTR;
        control = priv->line_control;
        spin_unlock_irqrestore (&priv->lock, flags);

        return set_control_lines (port->serial->dev, control);
}

static int pl2303_tiocmget (struct usb_serial_port *port, struct file *file)
{
        struct pl2303_private *priv = usb_get_serial_port_data(port);
        unsigned long flags;
        unsigned int mcr;
        unsigned int status;
        unsigned int result;

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

        spin_lock_irqsave (&priv->lock, flags);
        mcr = priv->line_control;
        status = priv->line_status;
        spin_unlock_irqrestore (&priv->lock, flags);

        result = ((mcr & CONTROL_DTR)           ? TIOCM_DTR : 0)
                  | ((mcr & CONTROL_RTS)        ? TIOCM_RTS : 0)
                  | ((status & UART_CTS)        ? TIOCM_CTS : 0)
                  | ((status & UART_DSR)        ? TIOCM_DSR : 0)
                  | ((status & UART_RING)       ? TIOCM_RI  : 0)
                  | ((status & UART_DCD)        ? TIOCM_CD  : 0);

        dbg("%s - result = %x", __FUNCTION__, result);

        return result;
}

static int pl2303_ioctl (struct usb_serial_port *port, struct file *file, unsigned int cmd, unsigned long arg)
{
        dbg("%s (%d) cmd = 0x%04x", __FUNCTION__, port->number, cmd);

        switch (cmd) {
                default:
                        dbg("%s not supported = 0x%04x", __FUNCTION__, cmd);
                        break;
        }

        return -ENOIOCTLCMD;
}

static void pl2303_break_ctl (struct usb_serial_port *port, int break_state)
{
        struct usb_serial *serial = port->serial;
        u16 state;
        int result;

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

        if (break_state == 0)
                state = BREAK_OFF;
        else
                state = BREAK_ON;
        dbg("%s - turning break %s", state==BREAK_OFF ? "off" : "on", __FUNCTION__);

        result = usb_control_msg (serial->dev, usb_sndctrlpipe (serial->dev, 0),
                                  BREAK_REQUEST, BREAK_REQUEST_TYPE, state,
                                  0, NULL, 0, 100);
        if (result)
                dbg("%s - error sending break = %d", __FUNCTION__, result);
}


static void pl2303_shutdown (struct usb_serial *serial)
{
        int i;

        dbg("%s", __FUNCTION__);

        for (i = 0; i < serial->num_ports; ++i) {
                kfree (usb_get_serial_port_data(serial->port[i]));
                usb_set_serial_port_data(serial->port[i], NULL);
        }              
}


static void pl2303_read_int_callback (struct urb *urb, struct pt_regs *regs)
{
        struct usb_serial_port *port = (struct usb_serial_port *) urb->context;
        struct usb_serial *serial = get_usb_serial (port, __FUNCTION__);
        struct pl2303_private *priv = usb_get_serial_port_data(port);
        unsigned char *data = urb->transfer_buffer;
        unsigned long flags;
        int status;

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

        switch (urb->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", __FUNCTION__, urb->status);
                return;
        default:
                dbg("%s - nonzero urb status received: %d", __FUNCTION__, urb->status);
                goto exit;
        }

        if (!serial) {
                return;
        }

        usb_serial_debug_data (__FILE__, __FUNCTION__, urb->actual_length, urb->transfer_buffer);

        if (urb->actual_length < UART_STATE)
                goto exit;

        /* Save off the uart status for others to look at */
        spin_lock_irqsave(&priv->lock, flags);
        priv->line_status = data[UART_STATE];
        spin_unlock_irqrestore(&priv->lock, flags);
               
exit:
        status = usb_submit_urb (urb, GFP_ATOMIC);
        if (status)
                dev_err(&urb->dev->dev, "%s - usb_submit_urb failed with result %d\n",
                        __FUNCTION__, status);
}


static void pl2303_read_bulk_callback (struct urb *urb, struct pt_regs *regs)
{
        struct usb_serial_port *port = (struct usb_serial_port *) urb->context;
        struct usb_serial *serial = get_usb_serial (port, __FUNCTION__);
        struct pl2303_private *priv = usb_get_serial_port_data(port);
        struct tty_struct *tty;
        unsigned char *data = urb->transfer_buffer;
        unsigned long flags;
        int i;
        int result;
        u8 status;
        char tty_flag;

        if (port_paranoia_check (port, __FUNCTION__))
                return;

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

        if (!serial) {
                dbg("%s - bad serial pointer, exiting", __FUNCTION__);
                return;
        }


        if (urb->status) {
                dbg("%s - urb->status = %d", __FUNCTION__, urb->status);
                if (!port->open_count) {
                        dbg("%s - port is closed, exiting.", __FUNCTION__);
                        return;
                }
                if (urb->status == -EPROTO) {
                        /* PL2303 mysteriously fails with -EPROTO reschedule the read */
                        dbg("%s - caught -EPROTO, resubmitting the urb", __FUNCTION__);
                        urb->status = 0;
                        urb->dev = serial->dev;
                        result = usb_submit_urb(urb, GFP_ATOMIC);
                        if (result)
                                dev_err(&urb->dev->dev, "%s - failed resubmitting read urb, error %d\n", __FUNCTION__, result);
                        return;
                }
                dbg("%s - unable to handle the error, exiting.", __FUNCTION__);
                return;
        }

        usb_serial_debug_data (__FILE__, __FUNCTION__, urb->actual_length, data);

        /* get tty_flag from status */
        tty_flag = TTY_NORMAL;

        spin_lock_irqsave(&priv->lock, flags);
        status = priv->line_status;
        spin_unlock_irqrestore(&priv->lock, flags);

        /* break takes precedence over parity, */
        /* which takes precedence over framing errors */
        if (status & UART_BREAK_ERROR )
                tty_flag = TTY_BREAK;
        else if (status & UART_PARITY_ERROR)
                tty_flag = TTY_PARITY;
        else if (status & UART_FRAME_ERROR)
                tty_flag = TTY_FRAME;
        dbg("%s - tty_flag = %d", __FUNCTION__, tty_flag);

        tty = port->tty;
        if (tty && urb->actual_length) {
                /* overrun is special, not associated with a char */
                if (status & UART_OVERRUN_ERROR)
                        tty_insert_flip_char(tty, 0, TTY_OVERRUN);
                for (i = 0; i < urb->actual_length; ++i) {
                        if (tty->flip.count >= TTY_FLIPBUF_SIZE) {
                                tty_flip_buffer_push(tty);
                        }
//**#ifdef DEBUG_ME
                        tty_insert_flip_char (tty, data[i], tty_flag);
//**#endif /* DEBUG_ME */
                }
                tty_flip_buffer_push (tty);
        }


        /* Schedule the next read _if_ we are still open */
        if (port->open_count) {
                urb->dev = serial->dev;
                result = usb_submit_urb(urb, GFP_ATOMIC);
                if (result)
                        dev_err(&urb->dev->dev, "%s - failed resubmitting read urb, error %d\n", __FUNCTION__, result);
        }


        return;
}



static void pl2303_write_bulk_callback (struct urb *urb, struct pt_regs *regs)
{
        struct usb_serial_port *port = (struct usb_serial_port *) urb->context;
        int result;

        if (port_paranoia_check (port, __FUNCTION__))
                return;
       
        dbg("%s - port %d", __FUNCTION__, port->number);
       
        if (urb->status) {
                /* error in the urb, so we have to resubmit it */
                if (serial_paranoia_check (port->serial, __FUNCTION__)) {
                        return;
                }
                dbg("%s - Overflow in write", __FUNCTION__);
                dbg("%s - nonzero write bulk status received: %d", __FUNCTION__, urb->status);
                port->write_urb->transfer_buffer_length = 1;
                port->write_urb->dev = port->serial->dev;
                result = usb_submit_urb (port->write_urb, GFP_ATOMIC);
                if (result)
                        dev_err(&urb->dev->dev, "%s - failed resubmitting write urb, error %d\n", __FUNCTION__, result);

                return;
        }

        schedule_work(&port->work);
}


/*static*/ int __init pl2303_init (void)
{
        int retval;
        retval = usb_serial_register(&pl2303_device);
        if (retval)
                goto failed_usb_serial_register;
        retval = usb_register(&pl2303_driver);
        if (retval)
                goto failed_usb_register;
        info(DRIVER_DESC " " DRIVER_VERSION);
        return 0;
failed_usb_register:
        usb_serial_deregister(&pl2303_device);
failed_usb_serial_register:
        return retval;
}


/*static*/ void __exit pl2303_exit (void)
{
        usb_deregister (&pl2303_driver);
        usb_serial_deregister (&pl2303_device);
}


module_init(pl2303_init);
module_exit(pl2303_exit);

MODULE_DESCRIPTION(DRIVER_DESC);
MODULE_LICENSE("GPL");

MODULE_PARM(debug, "i");
MODULE_PARM_DESC(debug, "Debug enabled or not");