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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
24struct usbcons_info {
25 int magic;
26 int break_flag;
27 struct usb_serial_port *port;
28};
29
30static struct usbcons_info usbcons_info;
31static 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
50/*
51 * The parsing of the command line works exactly like the
52 * serial.c code, except that the specifier is "ttyUSB" instead
53 * of "ttyS".
54 */
55static int usb_console_setup(struct console *co, char *options)
56{
57 struct usbcons_info *info = &usbcons_info;
58 int baud = 9600;
59 int bits = 8;
60 int parity = 'n';
61 int doflow = 0;
62 int cflag = CREAD | HUPCL | CLOCAL;
63 char *s;
64 struct usb_serial *serial;
65 struct usb_serial_port *port;
66 int retval;
67 struct tty_struct *tty = NULL;
68 struct ktermios dummy;
69
70 if (options) {
71 baud = simple_strtoul(options, NULL, 10);
72 s = options;
73 while (*s >= '0' && *s <= '9')
74 s++;
75 if (*s)
76 parity = *s++;
77 if (*s)
78 bits = *s++ - '0';
79 if (*s)
80 doflow = (*s++ == 'r');
81 }
82
83 /* Sane default */
84 if (baud == 0)
85 baud = 9600;
86
87 switch (bits) {
88 case 7:
89 cflag |= CS7;
90 break;
91 default:
92 case 8:
93 cflag |= CS8;
94 break;
95 }
96 switch (parity) {
97 case 'o': case 'O':
98 cflag |= PARODD;
99 break;
100 case 'e': case 'E':
101 cflag |= PARENB;
102 break;
103 }
104 co->cflag = cflag;
105
106 /*
107 * no need to check the index here: if the index is wrong, console
108 * code won't call us
109 */
110 port = usb_serial_port_get_by_minor(co->index);
111 if (port == NULL) {
112 /* no device is connected yet, sorry :( */
113 pr_err("No USB device connected to ttyUSB%i\n", co->index);
114 return -ENODEV;
115 }
116 serial = port->serial;
117
118 retval = usb_autopm_get_interface(serial->interface);
119 if (retval)
120 goto error_get_interface;
121
122 tty_port_tty_set(&port->port, NULL);
123
124 info->port = port;
125
126 ++port->port.count;
127 if (!test_bit(ASYNCB_INITIALIZED, &port->port.flags)) {
128 if (serial->type->set_termios) {
129 /*
130 * allocate a fake tty so the driver can initialize
131 * the termios structure, then later call set_termios to
132 * configure according to command line arguments
133 */
134 tty = kzalloc(sizeof(*tty), GFP_KERNEL);
135 if (!tty) {
136 retval = -ENOMEM;
137 goto reset_open_count;
138 }
139 kref_init(&tty->kref);
140 tty_port_tty_set(&port->port, tty);
141 tty->driver = usb_serial_tty_driver;
142 tty->index = co->index;
143 if (tty_init_termios(tty)) {
144 retval = -ENOMEM;
145 goto free_tty;
146 }
147 }
148
149 /* only call the device specific open if this
150 * is the first time the port is opened */
151 retval = serial->type->open(NULL, port);
152 if (retval) {
153 dev_err(&port->dev, "could not open USB console port\n");
154 goto fail;
155 }
156
157 if (serial->type->set_termios) {
158 tty->termios.c_cflag = cflag;
159 tty_termios_encode_baud_rate(&tty->termios, baud, baud);
160 memset(&dummy, 0, sizeof(struct ktermios));
161 serial->type->set_termios(tty, port, &dummy);
162
163 tty_port_tty_set(&port->port, NULL);
164 kfree(tty);
165 }
166 set_bit(ASYNCB_INITIALIZED, &port->port.flags);
167 }
168 /* Now that any required fake tty operations are completed restore
169 * the tty port count */
170 --port->port.count;
171 /* The console is special in terms of closing the device so
172 * indicate this port is now acting as a system console. */
173 port->port.console = 1;
174
175 mutex_unlock(&serial->disc_mutex);
176 return retval;
177
178 fail:
179 tty_port_tty_set(&port->port, NULL);
180 free_tty:
181 kfree(tty);
182 reset_open_count:
183 port->port.count = 0;
184 usb_autopm_put_interface(serial->interface);
185 error_get_interface:
186 usb_serial_put(serial);
187 mutex_unlock(&serial->disc_mutex);
188 return retval;
189}
190
191static void usb_console_write(struct console *co,
192 const char *buf, unsigned count)
193{
194 static struct usbcons_info *info = &usbcons_info;
195 struct usb_serial_port *port = info->port;
196 struct usb_serial *serial;
197 int retval = -ENODEV;
198
199 if (!port || port->serial->dev->state == USB_STATE_NOTATTACHED)
200 return;
201 serial = port->serial;
202
203 if (count == 0)
204 return;
205
206 dev_dbg(&port->dev, "%s - %d byte(s)\n", __func__, count);
207
208 if (!port->port.console) {
209 dev_dbg(&port->dev, "%s - port not opened\n", __func__);
210 return;
211 }
212
213 while (count) {
214 unsigned int i;
215 unsigned int lf;
216 /* search for LF so we can insert CR if necessary */
217 for (i = 0, lf = 0 ; i < count ; i++) {
218 if (*(buf + i) == 10) {
219 lf = 1;
220 i++;
221 break;
222 }
223 }
224 /* pass on to the driver specific version of this function if
225 it is available */
226 retval = serial->type->write(NULL, port, buf, i);
227 dev_dbg(&port->dev, "%s - write: %d\n", __func__, retval);
228 if (lf) {
229 /* append CR after LF */
230 unsigned char cr = 13;
231 retval = serial->type->write(NULL, port, &cr, 1);
232 dev_dbg(&port->dev, "%s - write cr: %d\n",
233 __func__, retval);
234 }
235 buf += i;
236 count -= i;
237 }
238}
239
240static struct tty_driver *usb_console_device(struct console *co, int *index)
241{
242 struct tty_driver **p = (struct tty_driver **)co->data;
243
244 if (!*p)
245 return NULL;
246
247 *index = co->index;
248 return *p;
249}
250
251static struct console usbcons = {
252 .name = "ttyUSB",
253 .write = usb_console_write,
254 .device = usb_console_device,
255 .setup = usb_console_setup,
256 .flags = CON_PRINTBUFFER,
257 .index = -1,
258 .data = &usb_serial_tty_driver,
259};
260
261void usb_serial_console_disconnect(struct usb_serial *serial)
262{
263 if (serial && serial->port && serial->port[0]
264 && serial->port[0] == usbcons_info.port) {
265 usb_serial_console_exit();
266 usb_serial_put(serial);
267 }
268}
269
270void usb_serial_console_init(int minor)
271{
272 if (minor == 0) {
273 /*
274 * Call register_console() if this is the first device plugged
275 * in. If we call it earlier, then the callback to
276 * console_setup() will fail, as there is not a device seen by
277 * the USB subsystem yet.
278 */
279 /*
280 * Register console.
281 * NOTES:
282 * console_setup() is called (back) immediately (from
283 * register_console). console_write() is called immediately
284 * from register_console iff CON_PRINTBUFFER is set in flags.
285 */
286 pr_debug("registering the USB serial console.\n");
287 register_console(&usbcons);
288 }
289}
290
291void usb_serial_console_exit(void)
292{
293 if (usbcons_info.port) {
294 unregister_console(&usbcons);
295 usbcons_info.port->port.console = 0;
296 usbcons_info.port = NULL;
297 }
298}
299