1 /*
2 * USB Serial Console driver
3 *
4 * Copyright (C) 2001 - 2002 Greg Kroah-Hartman (greg@kroah.com)
5 *
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.
9 *
10 * Thanks to Randy Dunlap for the original version of this code.
11 *
12 */
13
14 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
15
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>
23
24 struct usbcons_info {
25 int magic;
26 int break_flag;
27 struct usb_serial_port *port;
28 };
29
30 static struct usbcons_info usbcons_info;
31 static struct console usbcons;
32
33 /*
34 * ------------------------------------------------------------
35 * USB Serial console driver
36 *
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.
41 *
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 * ------------------------------------------------------------
47 */
48
49 static const struct tty_operations usb_console_fake_tty_ops = {
50 };
51
52 /*
53 * The parsing of the command line works exactly like the
54 * serial.c code, except that the specifier is "ttyUSB" instead
55 * of "ttyS".
56 */
usb_console_setup(struct console * co,char * options)57 static int usb_console_setup(struct console *co, char *options)
58 {
59 struct usbcons_info *info = &usbcons_info;
60 int baud = 9600;
61 int bits = 8;
62 int parity = 'n';
63 int doflow = 0;
64 int cflag = CREAD | HUPCL | CLOCAL;
65 char *s;
66 struct usb_serial *serial;
67 struct usb_serial_port *port;
68 int retval;
69 struct tty_struct *tty = NULL;
70 struct ktermios dummy;
71
72 if (options) {
73 baud = simple_strtoul(options, NULL, 10);
74 s = options;
75 while (*s >= '0' && *s <= '9')
76 s++;
77 if (*s)
78 parity = *s++;
79 if (*s)
80 bits = *s++ - '0';
81 if (*s)
82 doflow = (*s++ == 'r');
83 }
84
85 /* Sane default */
86 if (baud == 0)
87 baud = 9600;
88
89 switch (bits) {
90 case 7:
91 cflag |= CS7;
92 break;
93 default:
94 case 8:
95 cflag |= CS8;
96 break;
97 }
98 switch (parity) {
99 case 'o': case 'O':
100 cflag |= PARODD;
101 break;
102 case 'e': case 'E':
103 cflag |= PARENB;
104 break;
105 }
106 co->cflag = cflag;
107
108 /*
109 * no need to check the index here: if the index is wrong, console
110 * code won't call us
111 */
112 port = usb_serial_port_get_by_minor(co->index);
113 if (port == NULL) {
114 /* no device is connected yet, sorry :( */
115 pr_err("No USB device connected to ttyUSB%i\n", co->index);
116 return -ENODEV;
117 }
118 serial = port->serial;
119
120 retval = usb_autopm_get_interface(serial->interface);
121 if (retval)
122 goto error_get_interface;
123
124 tty_port_tty_set(&port->port, NULL);
125
126 info->port = port;
127
128 ++port->port.count;
129 if (!test_bit(ASYNCB_INITIALIZED, &port->port.flags)) {
130 if (serial->type->set_termios) {
131 /*
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
135 */
136 tty = kzalloc(sizeof(*tty), GFP_KERNEL);
137 if (!tty) {
138 retval = -ENOMEM;
139 goto reset_open_count;
140 }
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)) {
149 retval = -ENOMEM;
150 goto put_tty;
151 }
152 tty_port_tty_set(&port->port, tty);
153 }
154
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);
158 if (retval) {
159 dev_err(&port->dev, "could not open USB console port\n");
160 goto fail;
161 }
162
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);
168
169 tty_port_tty_set(&port->port, NULL);
170 tty_kref_put(tty);
171 }
172 set_bit(ASYNCB_INITIALIZED, &port->port.flags);
173 }
174 /* Now that any required fake tty operations are completed restore
175 * the tty port count */
176 --port->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;
180
181 mutex_unlock(&serial->disc_mutex);
182 return retval;
183
184 fail:
185 tty_port_tty_set(&port->port, NULL);
186 put_tty:
187 tty_kref_put(tty);
188 reset_open_count:
189 port->port.count = 0;
190 info->port = NULL;
191 usb_autopm_put_interface(serial->interface);
192 error_get_interface:
193 usb_serial_put(serial);
194 mutex_unlock(&serial->disc_mutex);
195 return retval;
196 }
197
usb_console_write(struct console * co,const char * buf,unsigned count)198 static void usb_console_write(struct console *co,
199 const char *buf, unsigned count)
200 {
201 static struct usbcons_info *info = &usbcons_info;
202 struct usb_serial_port *port = info->port;
203 struct usb_serial *serial;
204 int retval = -ENODEV;
205
206 if (!port || port->serial->dev->state == USB_STATE_NOTATTACHED)
207 return;
208 serial = port->serial;
209
210 if (count == 0)
211 return;
212
213 dev_dbg(&port->dev, "%s - %d byte(s)\n", __func__, count);
214
215 if (!port->port.console) {
216 dev_dbg(&port->dev, "%s - port not opened\n", __func__);
217 return;
218 }
219
220 while (count) {
221 unsigned int i;
222 unsigned int lf;
223 /* search for LF so we can insert CR if necessary */
224 for (i = 0, lf = 0 ; i < count ; i++) {
225 if (*(buf + i) == 10) {
226 lf = 1;
227 i++;
228 break;
229 }
230 }
231 /* pass on to the driver specific version of this function if
232 it is available */
233 retval = serial->type->write(NULL, port, buf, i);
234 dev_dbg(&port->dev, "%s - write: %d\n", __func__, retval);
235 if (lf) {
236 /* append CR after LF */
237 unsigned char cr = 13;
238 retval = serial->type->write(NULL, port, &cr, 1);
239 dev_dbg(&port->dev, "%s - write cr: %d\n",
240 __func__, retval);
241 }
242 buf += i;
243 count -= i;
244 }
245 }
246
usb_console_device(struct console * co,int * index)247 static struct tty_driver *usb_console_device(struct console *co, int *index)
248 {
249 struct tty_driver **p = (struct tty_driver **)co->data;
250
251 if (!*p)
252 return NULL;
253
254 *index = co->index;
255 return *p;
256 }
257
258 static struct console usbcons = {
259 .name = "ttyUSB",
260 .write = usb_console_write,
261 .device = usb_console_device,
262 .setup = usb_console_setup,
263 .flags = CON_PRINTBUFFER,
264 .index = -1,
265 .data = &usb_serial_tty_driver,
266 };
267
usb_serial_console_disconnect(struct usb_serial * serial)268 void usb_serial_console_disconnect(struct usb_serial *serial)
269 {
270 if (serial && serial->port && serial->port[0]
271 && serial->port[0] == usbcons_info.port) {
272 usb_serial_console_exit();
273 usb_serial_put(serial);
274 }
275 }
276
usb_serial_console_init(int minor)277 void usb_serial_console_init(int minor)
278 {
279 if (minor == 0) {
280 /*
281 * Call register_console() if this is the first device plugged
282 * in. If we call it earlier, then the callback to
283 * console_setup() will fail, as there is not a device seen by
284 * the USB subsystem yet.
285 */
286 /*
287 * Register console.
288 * NOTES:
289 * console_setup() is called (back) immediately (from
290 * register_console). console_write() is called immediately
291 * from register_console iff CON_PRINTBUFFER is set in flags.
292 */
293 pr_debug("registering the USB serial console.\n");
294 register_console(&usbcons);
295 }
296 }
297
usb_serial_console_exit(void)298 void usb_serial_console_exit(void)
299 {
300 if (usbcons_info.port) {
301 unregister_console(&usbcons);
302 usbcons_info.port->port.console = 0;
303 usbcons_info.port = NULL;
304 }
305 }
306
307