2 * USB Serial Console driver
4 * Copyright (C) 2001 - 2002 Greg Kroah-Hartman (greg@kroah.com)
6 * This program is free software; you can redistribute it and/or
7 * modify it under the terms of the GNU General Public License version
8 * 2 as published by the Free Software Foundation.
10 * Thanks to Randy Dunlap for the original version of this code.
14 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
16 #include <linux/kernel.h>
17 #include <linux/init.h>
18 #include <linux/slab.h>
19 #include <linux/tty.h>
20 #include <linux/console.h>
21 #include <linux/serial.h>
22 #include <linux/usb.h>
23 #include <linux/usb/serial.h>
28 struct usb_serial_port *port;
31 static struct usbcons_info usbcons_info;
32 static struct console usbcons;
35 * ------------------------------------------------------------
36 * USB Serial console driver
38 * Much of the code here is copied from drivers/char/serial.c
39 * and implements a phony serial console in the same way that
40 * serial.c does so that in case some software queries it,
41 * it will get the same results.
43 * Things that are different from the way the serial port code
44 * does things, is that we call the lower level usb-serial
45 * driver code to initialize the device, and we set the initial
46 * console speeds based on the command line arguments.
47 * ------------------------------------------------------------
52 * The parsing of the command line works exactly like the
53 * serial.c code, except that the specifier is "ttyUSB" instead
56 static int usb_console_setup(struct console *co, char *options)
58 struct usbcons_info *info = &usbcons_info;
63 int cflag = CREAD | HUPCL | CLOCAL;
65 struct usb_serial *serial;
66 struct usb_serial_port *port;
68 struct tty_struct *tty = NULL;
69 struct ktermios dummy;
72 baud = simple_strtoul(options, NULL, 10);
74 while (*s >= '0' && *s <= '9')
81 doflow = (*s++ == 'r');
108 * no need to check the index here: if the index is wrong, console
111 port = usb_serial_port_get_by_minor(co->index);
113 /* no device is connected yet, sorry :( */
114 pr_err("No USB device connected to ttyUSB%i\n", co->index);
117 serial = port->serial;
119 retval = usb_autopm_get_interface(serial->interface);
121 goto error_get_interface;
123 tty_port_tty_set(&port->port, NULL);
128 if (!test_bit(ASYNCB_INITIALIZED, &port->port.flags)) {
129 if (serial->type->set_termios) {
131 * allocate a fake tty so the driver can initialize
132 * the termios structure, then later call set_termios to
133 * configure according to command line arguments
135 tty = kzalloc(sizeof(*tty), GFP_KERNEL);
138 goto reset_open_count;
140 kref_init(&tty->kref);
141 tty_port_tty_set(&port->port, tty);
142 tty->driver = usb_serial_tty_driver;
143 tty->index = co->index;
144 if (tty_init_termios(tty)) {
150 /* only call the device specific open if this
151 * is the first time the port is opened */
152 retval = serial->type->open(NULL, port);
154 dev_err(&port->dev, "could not open USB console port\n");
158 if (serial->type->set_termios) {
159 tty->termios.c_cflag = cflag;
160 tty_termios_encode_baud_rate(&tty->termios, baud, baud);
161 memset(&dummy, 0, sizeof(struct ktermios));
162 serial->type->set_termios(tty, port, &dummy);
164 tty_port_tty_set(&port->port, NULL);
167 set_bit(ASYNCB_INITIALIZED, &port->port.flags);
169 /* Now that any required fake tty operations are completed restore
170 * the tty port count */
172 /* The console is special in terms of closing the device so
173 * indicate this port is now acting as a system console. */
174 port->port.console = 1;
176 mutex_unlock(&serial->disc_mutex);
180 tty_port_tty_set(&port->port, NULL);
184 port->port.count = 0;
185 usb_autopm_put_interface(serial->interface);
187 usb_serial_put(serial);
188 mutex_unlock(&serial->disc_mutex);
192 static void usb_console_write(struct console *co,
193 const char *buf, unsigned count)
195 static struct usbcons_info *info = &usbcons_info;
196 struct usb_serial_port *port = info->port;
197 struct usb_serial *serial;
198 int retval = -ENODEV;
200 if (!port || port->serial->dev->state == USB_STATE_NOTATTACHED)
202 serial = port->serial;
207 dev_dbg(&port->dev, "%s - %d byte(s)\n", __func__, count);
209 if (!port->port.console) {
210 dev_dbg(&port->dev, "%s - port not opened\n", __func__);
217 /* search for LF so we can insert CR if necessary */
218 for (i = 0, lf = 0 ; i < count ; i++) {
219 if (*(buf + i) == 10) {
225 /* pass on to the driver specific version of this function if
227 retval = serial->type->write(NULL, port, buf, i);
228 dev_dbg(&port->dev, "%s - write: %d\n", __func__, retval);
230 /* append CR after LF */
231 unsigned char cr = 13;
232 retval = serial->type->write(NULL, port, &cr, 1);
233 dev_dbg(&port->dev, "%s - write cr: %d\n",
241 static struct tty_driver *usb_console_device(struct console *co, int *index)
243 struct tty_driver **p = (struct tty_driver **)co->data;
252 static struct console usbcons = {
254 .write = usb_console_write,
255 .device = usb_console_device,
256 .setup = usb_console_setup,
257 .flags = CON_PRINTBUFFER,
259 .data = &usb_serial_tty_driver,
262 void usb_serial_console_disconnect(struct usb_serial *serial)
264 if (serial && serial->port && serial->port[0]
265 && serial->port[0] == usbcons_info.port) {
266 usb_serial_console_exit();
267 usb_serial_put(serial);
271 void usb_serial_console_init(int minor)
275 * Call register_console() if this is the first device plugged
276 * in. If we call it earlier, then the callback to
277 * console_setup() will fail, as there is not a device seen by
278 * the USB subsystem yet.
283 * console_setup() is called (back) immediately (from
284 * register_console). console_write() is called immediately
285 * from register_console iff CON_PRINTBUFFER is set in flags.
287 pr_debug("registering the USB serial console.\n");
288 register_console(&usbcons);
292 void usb_serial_console_exit(void)
294 if (usbcons_info.port) {
295 unregister_console(&usbcons);
296 usbcons_info.port->port.console = 0;
297 usbcons_info.port = NULL;