![Guennadi Liakhovetski](/assets/img/avatar_default.png)
Prevent sending further output to a USB-serial console after the dongle is disconnected, take care not to leak kref. Signed-off-by: Guennadi Liakhovetski <g.liakhovetski@gmx.de> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
299 lines
6.6 KiB
C
299 lines
6.6 KiB
C
/*
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* USB Serial Console driver
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*
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* Copyright (C) 2001 - 2002 Greg Kroah-Hartman (greg@kroah.com)
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*
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* This program is free software; you can redistribute it and/or
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* modify it under the terms of the GNU General Public License version
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* 2 as published by the Free Software Foundation.
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*
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* Thanks to Randy Dunlap for the original version of this code.
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*
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*/
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#include <linux/config.h>
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#include <linux/kernel.h>
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#include <linux/init.h>
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#include <linux/slab.h>
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#include <linux/tty.h>
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#include <linux/console.h>
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#include <linux/usb.h>
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static int debug;
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#include "usb-serial.h"
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struct usbcons_info {
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int magic;
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int break_flag;
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struct usb_serial_port *port;
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};
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static struct usbcons_info usbcons_info;
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static struct console usbcons;
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/*
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* ------------------------------------------------------------
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* USB Serial console driver
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*
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* Much of the code here is copied from drivers/char/serial.c
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* and implements a phony serial console in the same way that
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* serial.c does so that in case some software queries it,
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* it will get the same results.
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*
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* Things that are different from the way the serial port code
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* does things, is that we call the lower level usb-serial
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* driver code to initialize the device, and we set the initial
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* console speeds based on the command line arguments.
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* ------------------------------------------------------------
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*/
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/*
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* The parsing of the command line works exactly like the
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* serial.c code, except that the specifier is "ttyUSB" instead
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* of "ttyS".
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*/
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static int usb_console_setup(struct console *co, char *options)
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{
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struct usbcons_info *info = &usbcons_info;
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int baud = 9600;
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int bits = 8;
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int parity = 'n';
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int doflow = 0;
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int cflag = CREAD | HUPCL | CLOCAL;
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char *s;
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struct usb_serial *serial;
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struct usb_serial_port *port;
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int retval = 0;
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struct tty_struct *tty;
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struct termios *termios;
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dbg ("%s", __FUNCTION__);
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if (options) {
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baud = simple_strtoul(options, NULL, 10);
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s = options;
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while (*s >= '0' && *s <= '9')
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s++;
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if (*s)
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parity = *s++;
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if (*s)
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bits = *s++ - '0';
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if (*s)
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doflow = (*s++ == 'r');
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}
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/* build a cflag setting */
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switch (baud) {
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case 1200:
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cflag |= B1200;
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break;
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case 2400:
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cflag |= B2400;
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break;
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case 4800:
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cflag |= B4800;
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break;
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case 19200:
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cflag |= B19200;
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break;
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case 38400:
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cflag |= B38400;
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break;
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case 57600:
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cflag |= B57600;
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break;
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case 115200:
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cflag |= B115200;
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break;
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case 9600:
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default:
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cflag |= B9600;
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/*
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* Set this to a sane value to prevent a divide error
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*/
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baud = 9600;
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break;
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}
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switch (bits) {
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case 7:
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cflag |= CS7;
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break;
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default:
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case 8:
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cflag |= CS8;
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break;
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}
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switch (parity) {
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case 'o': case 'O':
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cflag |= PARODD;
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break;
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case 'e': case 'E':
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cflag |= PARENB;
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break;
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}
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co->cflag = cflag;
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/* grab the first serial port that happens to be connected */
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serial = usb_serial_get_by_index(0);
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if (serial == NULL) {
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/* no device is connected yet, sorry :( */
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err ("No USB device connected to ttyUSB0");
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return -ENODEV;
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}
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port = serial->port[0];
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port->tty = NULL;
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info->port = port;
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++port->open_count;
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if (port->open_count == 1) {
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/* only call the device specific open if this
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* is the first time the port is opened */
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if (serial->type->open)
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retval = serial->type->open(port, NULL);
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else
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retval = usb_serial_generic_open(port, NULL);
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if (retval)
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port->open_count = 0;
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}
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if (retval) {
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err ("could not open USB console port");
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return retval;
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}
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if (serial->type->set_termios) {
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/* build up a fake tty structure so that the open call has something
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* to look at to get the cflag value */
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tty = kmalloc (sizeof (*tty), GFP_KERNEL);
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if (!tty) {
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err ("no more memory");
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return -ENOMEM;
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}
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termios = kmalloc (sizeof (*termios), GFP_KERNEL);
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if (!termios) {
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err ("no more memory");
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kfree (tty);
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return -ENOMEM;
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}
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memset (tty, 0x00, sizeof(*tty));
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memset (termios, 0x00, sizeof(*termios));
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termios->c_cflag = cflag;
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tty->termios = termios;
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port->tty = tty;
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/* set up the initial termios settings */
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serial->type->set_termios(port, NULL);
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port->tty = NULL;
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kfree (termios);
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kfree (tty);
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}
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return retval;
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}
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static void usb_console_write(struct console *co, const char *buf, unsigned count)
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{
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static struct usbcons_info *info = &usbcons_info;
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struct usb_serial_port *port = info->port;
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struct usb_serial *serial;
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int retval = -ENODEV;
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if (!port || port->serial->dev->state == USB_STATE_NOTATTACHED)
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return;
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serial = port->serial;
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if (count == 0)
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return;
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dbg("%s - port %d, %d byte(s)", __FUNCTION__, port->number, count);
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if (!port->open_count) {
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dbg ("%s - port not opened", __FUNCTION__);
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return;
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}
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while (count) {
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unsigned int i;
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unsigned int lf;
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/* search for LF so we can insert CR if necessary */
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for (i=0, lf=0 ; i < count ; i++) {
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if (*(buf + i) == 10) {
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lf = 1;
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i++;
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break;
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}
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}
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/* pass on to the driver specific version of this function if it is available */
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if (serial->type->write)
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retval = serial->type->write(port, buf, i);
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else
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retval = usb_serial_generic_write(port, buf, i);
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dbg("%s - return value : %d", __FUNCTION__, retval);
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if (lf) {
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/* append CR after LF */
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unsigned char cr = 13;
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if (serial->type->write)
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retval = serial->type->write(port, &cr, 1);
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else
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retval = usb_serial_generic_write(port, &cr, 1);
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dbg("%s - return value : %d", __FUNCTION__, retval);
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}
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buf += i;
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count -= i;
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}
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}
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static struct console usbcons = {
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.name = "ttyUSB",
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.write = usb_console_write,
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.setup = usb_console_setup,
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.flags = CON_PRINTBUFFER,
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.index = -1,
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};
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void usb_serial_console_disconnect(struct usb_serial *serial)
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{
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if (serial && serial->port && serial->port[0] && serial->port[0] == usbcons_info.port) {
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usb_serial_console_exit();
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usb_serial_put(serial);
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}
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}
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void usb_serial_console_init (int serial_debug, int minor)
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{
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debug = serial_debug;
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if (minor == 0) {
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/*
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* Call register_console() if this is the first device plugged
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* in. If we call it earlier, then the callback to
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* console_setup() will fail, as there is not a device seen by
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* the USB subsystem yet.
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*/
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/*
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* Register console.
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* NOTES:
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* console_setup() is called (back) immediately (from register_console).
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* console_write() is called immediately from register_console iff
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* CON_PRINTBUFFER is set in flags.
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*/
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dbg ("registering the USB serial console.");
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register_console(&usbcons);
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}
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}
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void usb_serial_console_exit (void)
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{
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if (usbcons_info.port) {
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unregister_console(&usbcons);
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if (usbcons_info.port->open_count)
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usbcons_info.port->open_count--;
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usbcons_info.port = NULL;
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}
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}
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