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/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>
24
25 struct usbcons_info {
26 int magic;
27 int break_flag;
28 struct usb_serial_port *port;
29 };
30
31 static struct usbcons_info usbcons_info;
32 static struct console usbcons;
33
34 /*
35 * ------------------------------------------------------------
36 * USB Serial console driver
37 *
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.
42 *
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 * ------------------------------------------------------------
48 */
49
50
51 /*
52 * The parsing of the command line works exactly like the
53 * serial.c code, except that the specifier is "ttyUSB" instead
54 * of "ttyS".
55 */
usb_console_setup(struct console * co,char * options)56 static int usb_console_setup(struct console *co, char *options)
57 {
58 struct usbcons_info *info = &usbcons_info;
59 int baud = 9600;
60 int bits = 8;
61 int parity = 'n';
62 int doflow = 0;
63 int cflag = CREAD | HUPCL | CLOCAL;
64 char *s;
65 struct usb_serial *serial;
66 struct usb_serial_port *port;
67 int retval;
68 struct tty_struct *tty = NULL;
69 struct ktermios dummy;
70
71 if (options) {
72 baud = simple_strtoul(options, NULL, 10);
73 s = options;
74 while (*s >= '0' && *s <= '9')
75 s++;
76 if (*s)
77 parity = *s++;
78 if (*s)
79 bits = *s++ - '0';
80 if (*s)
81 doflow = (*s++ == 'r');
82 }
83
84 /* Sane default */
85 if (baud == 0)
86 baud = 9600;
87
88 switch (bits) {
89 case 7:
90 cflag |= CS7;
91 break;
92 default:
93 case 8:
94 cflag |= CS8;
95 break;
96 }
97 switch (parity) {
98 case 'o': case 'O':
99 cflag |= PARODD;
100 break;
101 case 'e': case 'E':
102 cflag |= PARENB;
103 break;
104 }
105 co->cflag = cflag;
106
107 /*
108 * no need to check the index here: if the index is wrong, console
109 * code won't call us
110 */
111 serial = usb_serial_get_by_index(co->index);
112 if (serial == NULL) {
113 /* no device is connected yet, sorry :( */
114 pr_err("No USB device connected to ttyUSB%i\n", co->index);
115 return -ENODEV;
116 }
117
118 retval = usb_autopm_get_interface(serial->interface);
119 if (retval)
120 goto error_get_interface;
121
122 port = serial->port[co->index - serial->minor];
123 tty_port_tty_set(&port->port, NULL);
124
125 info->port = port;
126
127 ++port->port.count;
128 if (!test_bit(ASYNCB_INITIALIZED, &port->port.flags)) {
129 if (serial->type->set_termios) {
130 /*
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
134 */
135 tty = kzalloc(sizeof(*tty), GFP_KERNEL);
136 if (!tty) {
137 retval = -ENOMEM;
138 dev_err(&port->dev, "no more memory\n");
139 goto reset_open_count;
140 }
141 kref_init(&tty->kref);
142 tty_port_tty_set(&port->port, tty);
143 tty->driver = usb_serial_tty_driver;
144 tty->index = co->index;
145 if (tty_init_termios(tty)) {
146 retval = -ENOMEM;
147 dev_err(&port->dev, "no more memory\n");
148 goto free_tty;
149 }
150 }
151
152 /* only call the device specific open if this
153 * is the first time the port is opened */
154 if (serial->type->open)
155 retval = serial->type->open(NULL, port);
156 else
157 retval = usb_serial_generic_open(NULL, port);
158
159 if (retval) {
160 dev_err(&port->dev, "could not open USB console port\n");
161 goto fail;
162 }
163
164 if (serial->type->set_termios) {
165 tty->termios.c_cflag = cflag;
166 tty_termios_encode_baud_rate(&tty->termios, baud, baud);
167 memset(&dummy, 0, sizeof(struct ktermios));
168 serial->type->set_termios(tty, port, &dummy);
169
170 tty_port_tty_set(&port->port, NULL);
171 kfree(tty);
172 }
173 set_bit(ASYNCB_INITIALIZED, &port->port.flags);
174 }
175 /* Now that any required fake tty operations are completed restore
176 * the tty port count */
177 --port->port.count;
178 /* The console is special in terms of closing the device so
179 * indicate this port is now acting as a system console. */
180 port->port.console = 1;
181
182 mutex_unlock(&serial->disc_mutex);
183 return retval;
184
185 fail:
186 tty_port_tty_set(&port->port, NULL);
187 free_tty:
188 kfree(tty);
189 reset_open_count:
190 port->port.count = 0;
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 pr_debug("%s - port %d, %d byte(s)\n", __func__, port->number, count);
214
215 if (!port->port.console) {
216 pr_debug("%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 if (serial->type->write)
234 retval = serial->type->write(NULL, port, buf, i);
235 else
236 retval = usb_serial_generic_write(NULL, port, buf, i);
237 pr_debug("%s - return value : %d\n", __func__, retval);
238 if (lf) {
239 /* append CR after LF */
240 unsigned char cr = 13;
241 if (serial->type->write)
242 retval = serial->type->write(NULL,
243 port, &cr, 1);
244 else
245 retval = usb_serial_generic_write(NULL,
246 port, &cr, 1);
247 pr_debug("%s - return value : %d\n", __func__, retval);
248 }
249 buf += i;
250 count -= i;
251 }
252 }
253
usb_console_device(struct console * co,int * index)254 static struct tty_driver *usb_console_device(struct console *co, int *index)
255 {
256 struct tty_driver **p = (struct tty_driver **)co->data;
257
258 if (!*p)
259 return NULL;
260
261 *index = co->index;
262 return *p;
263 }
264
265 static struct console usbcons = {
266 .name = "ttyUSB",
267 .write = usb_console_write,
268 .device = usb_console_device,
269 .setup = usb_console_setup,
270 .flags = CON_PRINTBUFFER,
271 .index = -1,
272 .data = &usb_serial_tty_driver,
273 };
274
usb_serial_console_disconnect(struct usb_serial * serial)275 void usb_serial_console_disconnect(struct usb_serial *serial)
276 {
277 if (serial && serial->port && serial->port[0]
278 && serial->port[0] == usbcons_info.port) {
279 usb_serial_console_exit();
280 usb_serial_put(serial);
281 }
282 }
283
usb_serial_console_init(int minor)284 void usb_serial_console_init(int minor)
285 {
286 if (minor == 0) {
287 /*
288 * Call register_console() if this is the first device plugged
289 * in. If we call it earlier, then the callback to
290 * console_setup() will fail, as there is not a device seen by
291 * the USB subsystem yet.
292 */
293 /*
294 * Register console.
295 * NOTES:
296 * console_setup() is called (back) immediately (from
297 * register_console). console_write() is called immediately
298 * from register_console iff CON_PRINTBUFFER is set in flags.
299 */
300 pr_debug("registering the USB serial console.\n");
301 register_console(&usbcons);
302 }
303 }
304
usb_serial_console_exit(void)305 void usb_serial_console_exit(void)
306 {
307 if (usbcons_info.port) {
308 unregister_console(&usbcons);
309 usbcons_info.port->port.console = 0;
310 usbcons_info.port = NULL;
311 }
312 }
313
314