/*
 * USB Serial Console driver
 *
 * Copyright (C) 2001 - 2002 Greg Kroah-Hartman (greg@kroah.com)
 *
 *      This program is free software; you can redistribute it and/or
 *      modify it under the terms of the GNU General Public License version
 *      2 as published by the Free Software Foundation.
 * 
 * Thanks to Randy Dunlap for the original version of this code.
 *
 */

#include <linux/kernel.h>
#include <linux/init.h>
#include <linux/slab.h>
#include <linux/tty.h>
#include <linux/console.h>
#include <linux/usb.h>
#include <linux/usb/serial.h>

static int debug;

struct usbcons_info {
        int                     magic;
        int                     break_flag;
        struct usb_serial_port  *port;
};

static struct usbcons_info usbcons_info;
static struct console usbcons;

/*
 * ------------------------------------------------------------
 * USB Serial console driver
 *
 * Much of the code here is copied from drivers/char/serial.c
 * and implements a phony serial console in the same way that
 * serial.c does so that in case some software queries it,
 * it will get the same results.
 *
 * Things that are different from the way the serial port code
 * does things, is that we call the lower level usb-serial
 * driver code to initialize the device, and we set the initial
 * console speeds based on the command line arguments.
 * ------------------------------------------------------------
 */


/*
 * The parsing of the command line works exactly like the
 * serial.c code, except that the specifier is "ttyUSB" instead
 * of "ttyS".
 */
static int usb_console_setup(struct console *co, char *options)
{
        struct usbcons_info *info = &usbcons_info;
        int baud = 9600;
        int bits = 8;
        int parity = 'n';
        int doflow = 0;
        int cflag = CREAD | HUPCL | CLOCAL;
        char *s;
        struct usb_serial *serial;
        struct usb_serial_port *port;
        int retval = 0;
        struct tty_struct *tty;
        struct ktermios *termios;

        dbg ("%s", __FUNCTION__);

        if (options) {
                baud = simple_strtoul(options, NULL, 10);
                s = options;
                while (*s >= '0' && *s <= '9')
                        s++;
                if (*s)
                        parity = *s++;
                if (*s)
                        bits   = *s++ - '0';
                if (*s)
                        doflow = (*s++ == 'r');
        }

        /* build a cflag setting */
        switch (baud) {
                case 1200:
                        cflag |= B1200;
                        break;
                case 2400:
                        cflag |= B2400;
                        break;
                case 4800:
                        cflag |= B4800;
                        break;
                case 19200:
                        cflag |= B19200;
                        break;
                case 38400:
                        cflag |= B38400;
                        break;
                case 57600:
                        cflag |= B57600;
                        break;
                case 115200:
                        cflag |= B115200;
                        break;
                case 9600:
                default:
                        cflag |= B9600;
                        /*
                         * Set this to a sane value to prevent a divide error
                         */
                        baud  = 9600;
                        break;
        }
        switch (bits) {
                case 7:
                        cflag |= CS7;
                        break;
                default:
                case 8:
                        cflag |= CS8;
                        break;
        }
        switch (parity) {
                case 'o': case 'O':
                        cflag |= PARODD;
                        break;
                case 'e': case 'E':
                        cflag |= PARENB;
                        break;
        }
        co->cflag = cflag;

        /* grab the first serial port that happens to be connected */
        serial = usb_serial_get_by_index(0);
        if (serial == NULL) {
                /* no device is connected yet, sorry :( */
                err ("No USB device connected to ttyUSB0");
                return -ENODEV;
        }

        port = serial->port[0];
        port->tty = NULL;

        info->port = port;
         
        ++port->open_count;
        if (port->open_count == 1) {
                /* only call the device specific open if this 
                 * is the first time the port is opened */
                if (serial->type->open)
                        retval = serial->type->open(port, NULL);
                else
                        retval = usb_serial_generic_open(port, NULL);
                if (retval)
                        port->open_count = 0;
        }

        if (retval) {
                err ("could not open USB console port");
                return retval;
        }

        if (serial->type->set_termios) {
                struct ktermios dummy;
                /* build up a fake tty structure so that the open call has something
                 * to look at to get the cflag value */
                tty = kzalloc(sizeof(*tty), GFP_KERNEL);
                if (!tty) {
                        err ("no more memory");
                        return -ENOMEM;
                }
                termios = kzalloc(sizeof(*termios), GFP_KERNEL);
                if (!termios) {
                        err ("no more memory");
                        kfree (tty);
                        return -ENOMEM;
                }
                memset(&dummy, 0, sizeof(struct ktermios));
                termios->c_cflag = cflag;
                tty->termios = termios;
                port->tty = tty;

                /* set up the initial termios settings */
                serial->type->set_termios(port, &dummy);
                port->tty = NULL;
                kfree (termios);
                kfree (tty);
        }

        return retval;
}

static void usb_console_write(struct console *co, const char *buf, unsigned count)
{
        static struct usbcons_info *info = &usbcons_info;
        struct usb_serial_port *port = info->port;
        struct usb_serial *serial;
        int retval = -ENODEV;

        if (!port || port->serial->dev->state == USB_STATE_NOTATTACHED)
                return;
        serial = port->serial;

        if (count == 0)
                return;

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

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

        while (count) {
                unsigned int i;
                unsigned int lf;
                /* search for LF so we can insert CR if necessary */
                for (i=0, lf=0 ; i < count ; i++) {
                        if (*(buf + i) == 10) {
                                lf = 1;
                                i++;
                                break;
                        }
                }
                /* pass on to the driver specific version of this function if it is available */
                if (serial->type->write)
                        retval = serial->type->write(port, buf, i);
                else
                        retval = usb_serial_generic_write(port, buf, i);
                dbg("%s - return value : %d", __FUNCTION__, retval);
                if (lf) {
                        /* append CR after LF */
                        unsigned char cr = 13;
                        if (serial->type->write)
                                retval = serial->type->write(port, &cr, 1);
                        else
                                retval = usb_serial_generic_write(port, &cr, 1);
                        dbg("%s - return value : %d", __FUNCTION__, retval);
                }
                buf += i;
                count -= i;
        }
}

static struct console usbcons = {
        .name =         "ttyUSB",
        .write =        usb_console_write,
        .setup =        usb_console_setup,
        .flags =        CON_PRINTBUFFER,
        .index =        -1,
};

void usb_serial_console_disconnect(struct usb_serial *serial)
{
        if (serial && serial->port && serial->port[0] && serial->port[0] == usbcons_info.port) {
                usb_serial_console_exit();
                usb_serial_put(serial);
        }
}

void usb_serial_console_init (int serial_debug, int minor)
{
        debug = serial_debug;

        if (minor == 0) {
                /* 
                 * Call register_console() if this is the first device plugged
                 * in.  If we call it earlier, then the callback to
                 * console_setup() will fail, as there is not a device seen by
                 * the USB subsystem yet.
                 */
                /*
                 * Register console.
                 * NOTES:
                 * console_setup() is called (back) immediately (from register_console).
                 * console_write() is called immediately from register_console iff
                 * CON_PRINTBUFFER is set in flags.
                 */
                dbg ("registering the USB serial console.");
                register_console(&usbcons);
        }
}

void usb_serial_console_exit (void)
{
        if (usbcons_info.port) {
                unregister_console(&usbcons);
                if (usbcons_info.port->open_count)
                        usbcons_info.port->open_count--;
                usbcons_info.port = NULL;
        }
}