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/slab.h>
18 #include <linux/tty.h>
19 #include <linux/console.h>
20 #include <linux/serial.h>
21 #include <linux/usb.h>
22 #include <linux/usb/serial.h>
27 struct usb_serial_port *port;
30 static struct usbcons_info usbcons_info;
31 static struct console usbcons;
34 * ------------------------------------------------------------
35 * USB Serial console driver
37 * Much of the code here is copied from drivers/char/serial.c
38 * and implements a phony serial console in the same way that
39 * serial.c does so that in case some software queries it,
40 * it will get the same results.
42 * Things that are different from the way the serial port code
43 * does things, is that we call the lower level usb-serial
44 * driver code to initialize the device, and we set the initial
45 * console speeds based on the command line arguments.
46 * ------------------------------------------------------------
49 static const struct tty_operations usb_console_fake_tty_ops = {
53 * The parsing of the command line works exactly like the
54 * serial.c code, except that the specifier is "ttyUSB" instead
57 static int usb_console_setup(struct console *co, char *options)
59 struct usbcons_info *info = &usbcons_info;
64 int cflag = CREAD | HUPCL | CLOCAL;
66 struct usb_serial *serial;
67 struct usb_serial_port *port;
69 struct tty_struct *tty = NULL;
70 struct ktermios dummy;
73 baud = simple_strtoul(options, NULL, 10);
75 while (*s >= '0' && *s <= '9')
82 doflow = (*s++ == 'r');
109 * no need to check the index here: if the index is wrong, console
112 port = usb_serial_port_get_by_minor(co->index);
114 /* no device is connected yet, sorry :( */
115 pr_err("No USB device connected to ttyUSB%i\n", co->index);
118 serial = port->serial;
120 retval = usb_autopm_get_interface(serial->interface);
122 goto error_get_interface;
124 tty_port_tty_set(&port->port, NULL);
129 if (!test_bit(ASYNCB_INITIALIZED, &port->port.flags)) {
130 if (serial->type->set_termios) {
132 * allocate a fake tty so the driver can initialize
133 * the termios structure, then later call set_termios to
134 * configure according to command line arguments
136 tty = kzalloc(sizeof(*tty), GFP_KERNEL);
139 goto reset_open_count;
141 kref_init(&tty->kref);
142 tty->driver = usb_serial_tty_driver;
143 tty->index = co->index;
144 init_ldsem(&tty->ldisc_sem);
145 INIT_LIST_HEAD(&tty->tty_files);
146 kref_get(&tty->driver->kref);
147 tty->ops = &usb_console_fake_tty_ops;
148 if (tty_init_termios(tty)) {
152 tty_port_tty_set(&port->port, tty);
155 /* only call the device specific open if this
156 * is the first time the port is opened */
157 retval = serial->type->open(NULL, port);
159 dev_err(&port->dev, "could not open USB console port\n");
163 if (serial->type->set_termios) {
164 tty->termios.c_cflag = cflag;
165 tty_termios_encode_baud_rate(&tty->termios, baud, baud);
166 memset(&dummy, 0, sizeof(struct ktermios));
167 serial->type->set_termios(tty, port, &dummy);
169 tty_port_tty_set(&port->port, NULL);
172 set_bit(ASYNCB_INITIALIZED, &port->port.flags);
174 /* Now that any required fake tty operations are completed restore
175 * the tty port count */
177 /* The console is special in terms of closing the device so
178 * indicate this port is now acting as a system console. */
179 port->port.console = 1;
181 mutex_unlock(&serial->disc_mutex);
185 tty_port_tty_set(&port->port, NULL);
189 port->port.count = 0;
190 usb_autopm_put_interface(serial->interface);
192 usb_serial_put(serial);
193 mutex_unlock(&serial->disc_mutex);
197 static void usb_console_write(struct console *co,
198 const char *buf, unsigned count)
200 static struct usbcons_info *info = &usbcons_info;
201 struct usb_serial_port *port = info->port;
202 struct usb_serial *serial;
203 int retval = -ENODEV;
205 if (!port || port->serial->dev->state == USB_STATE_NOTATTACHED)
207 serial = port->serial;
212 dev_dbg(&port->dev, "%s - %d byte(s)\n", __func__, count);
214 if (!port->port.console) {
215 dev_dbg(&port->dev, "%s - port not opened\n", __func__);
222 /* search for LF so we can insert CR if necessary */
223 for (i = 0, lf = 0 ; i < count ; i++) {
224 if (*(buf + i) == 10) {
230 /* pass on to the driver specific version of this function if
232 retval = serial->type->write(NULL, port, buf, i);
233 dev_dbg(&port->dev, "%s - write: %d\n", __func__, retval);
235 /* append CR after LF */
236 unsigned char cr = 13;
237 retval = serial->type->write(NULL, port, &cr, 1);
238 dev_dbg(&port->dev, "%s - write cr: %d\n",
246 static struct tty_driver *usb_console_device(struct console *co, int *index)
248 struct tty_driver **p = (struct tty_driver **)co->data;
257 static struct console usbcons = {
259 .write = usb_console_write,
260 .device = usb_console_device,
261 .setup = usb_console_setup,
262 .flags = CON_PRINTBUFFER,
264 .data = &usb_serial_tty_driver,
267 void usb_serial_console_disconnect(struct usb_serial *serial)
269 if (serial && serial->port && serial->port[0]
270 && serial->port[0] == usbcons_info.port) {
271 usb_serial_console_exit();
272 usb_serial_put(serial);
276 void usb_serial_console_init(int minor)
280 * Call register_console() if this is the first device plugged
281 * in. If we call it earlier, then the callback to
282 * console_setup() will fail, as there is not a device seen by
283 * the USB subsystem yet.
288 * console_setup() is called (back) immediately (from
289 * register_console). console_write() is called immediately
290 * from register_console iff CON_PRINTBUFFER is set in flags.
292 pr_debug("registering the USB serial console.\n");
293 register_console(&usbcons);
297 void usb_serial_console_exit(void)
299 if (usbcons_info.port) {
300 unregister_console(&usbcons);
301 usbcons_info.port->port.console = 0;
302 usbcons_info.port = NULL;