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1// SPDX-License-Identifier: GPL-2.0
2/*
3 * USB Serial Console driver
4 *
5 * Copyright (C) 2001 - 2002 Greg Kroah-Hartman (greg@kroah.com)
6 *
7 * Thanks to Randy Dunlap for the original version of this code.
8 *
9 */
10
11#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
12
13#include <linux/kernel.h>
14#include <linux/module.h>
15#include <linux/slab.h>
16#include <linux/tty.h>
17#include <linux/console.h>
18#include <linux/serial.h>
19#include <linux/usb.h>
20#include <linux/usb/serial.h>
21
22struct usbcons_info {
23 int magic;
24 int break_flag;
25 struct usb_serial_port *port;
26};
27
28static struct usbcons_info usbcons_info;
29static struct console usbcons;
30
31/*
32 * ------------------------------------------------------------
33 * USB Serial console driver
34 *
35 * Much of the code here is copied from drivers/char/serial.c
36 * and implements a phony serial console in the same way that
37 * serial.c does so that in case some software queries it,
38 * it will get the same results.
39 *
40 * Things that are different from the way the serial port code
41 * does things, is that we call the lower level usb-serial
42 * driver code to initialize the device, and we set the initial
43 * console speeds based on the command line arguments.
44 * ------------------------------------------------------------
45 */
46
47static const struct tty_operations usb_console_fake_tty_ops = {
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
105 if (doflow)
106 cflag |= CRTSCTS;
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 (!tty_port_initialized(&port->port)) {
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 spin_lock_init(&tty->files_lock);
146 INIT_LIST_HEAD(&tty->tty_files);
147 kref_get(&tty->driver->kref);
148 __module_get(tty->driver->owner);
149 tty->ops = &usb_console_fake_tty_ops;
150 tty_init_termios(tty);
151 tty_port_tty_set(&port->port, tty);
152 }
153
154 /* only call the device specific open if this
155 * is the first time the port is opened */
156 retval = serial->type->open(NULL, port);
157 if (retval) {
158 dev_err(&port->dev, "could not open USB console port\n");
159 goto fail;
160 }
161
162 if (serial->type->set_termios) {
163 tty->termios.c_cflag = cflag;
164 tty_termios_encode_baud_rate(&tty->termios, baud, baud);
165 memset(&dummy, 0, sizeof(struct ktermios));
166 serial->type->set_termios(tty, port, &dummy);
167
168 tty_port_tty_set(&port->port, NULL);
169 tty_save_termios(tty);
170 tty_kref_put(tty);
171 }
172 tty_port_set_initialized(&port->port, true);
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 tty_kref_put(tty);
187 reset_open_count:
188 port->port.count = 0;
189 info->port = NULL;
190 usb_autopm_put_interface(serial->interface);
191 error_get_interface:
192 mutex_unlock(&serial->disc_mutex);
193 usb_serial_put(serial);
194 return retval;
195}
196
197static void usb_console_write(struct console *co,
198 const char *buf, unsigned count)
199{
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;
204
205 if (!port || port->serial->dev->state == USB_STATE_NOTATTACHED)
206 return;
207 serial = port->serial;
208
209 if (count == 0)
210 return;
211
212 dev_dbg(&port->dev, "%s - %d byte(s)\n", __func__, count);
213
214 if (!port->port.console) {
215 dev_dbg(&port->dev, "%s - port not opened\n", __func__);
216 return;
217 }
218
219 while (count) {
220 unsigned int i;
221 unsigned int lf;
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) {
225 lf = 1;
226 i++;
227 break;
228 }
229 }
230 /* pass on to the driver specific version of this function if
231 it is available */
232 retval = serial->type->write(NULL, port, buf, i);
233 dev_dbg(&port->dev, "%s - write: %d\n", __func__, retval);
234 if (lf) {
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",
239 __func__, retval);
240 }
241 buf += i;
242 count -= i;
243 }
244}
245
246static struct tty_driver *usb_console_device(struct console *co, int *index)
247{
248 struct tty_driver **p = (struct tty_driver **)co->data;
249
250 if (!*p)
251 return NULL;
252
253 *index = co->index;
254 return *p;
255}
256
257static struct console usbcons = {
258 .name = "ttyUSB",
259 .write = usb_console_write,
260 .device = usb_console_device,
261 .setup = usb_console_setup,
262 .flags = CON_PRINTBUFFER,
263 .index = -1,
264 .data = &usb_serial_tty_driver,
265};
266
267void usb_serial_console_disconnect(struct usb_serial *serial)
268{
269 if (serial->port[0] && serial->port[0] == usbcons_info.port) {
270 usb_serial_console_exit();
271 usb_serial_put(serial);
272 }
273}
274
275void usb_serial_console_init(int minor)
276{
277 if (minor == 0) {
278 /*
279 * Call register_console() if this is the first device plugged
280 * in. If we call it earlier, then the callback to
281 * console_setup() will fail, as there is not a device seen by
282 * the USB subsystem yet.
283 */
284 /*
285 * Register console.
286 * NOTES:
287 * console_setup() is called (back) immediately (from
288 * register_console). console_write() is called immediately
289 * from register_console iff CON_PRINTBUFFER is set in flags.
290 */
291 pr_debug("registering the USB serial console.\n");
292 register_console(&usbcons);
293 }
294}
295
296void usb_serial_console_exit(void)
297{
298 if (usbcons_info.port) {
299 unregister_console(&usbcons);
300 usbcons_info.port->port.console = 0;
301 usbcons_info.port = NULL;
302 }
303}
304
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#include <linux/kernel.h>
15#include <linux/init.h>
16#include <linux/slab.h>
17#include <linux/tty.h>
18#include <linux/console.h>
19#include <linux/serial.h>
20#include <linux/usb.h>
21#include <linux/usb/serial.h>
22
23static int debug;
24
25struct usbcons_info {
26 int magic;
27 int break_flag;
28 struct usb_serial_port *port;
29};
30
31static struct usbcons_info usbcons_info;
32static 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 */
56static 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 dbg("%s", __func__);
72
73 if (options) {
74 baud = simple_strtoul(options, NULL, 10);
75 s = options;
76 while (*s >= '0' && *s <= '9')
77 s++;
78 if (*s)
79 parity = *s++;
80 if (*s)
81 bits = *s++ - '0';
82 if (*s)
83 doflow = (*s++ == 'r');
84 }
85
86 /* Sane default */
87 if (baud == 0)
88 baud = 9600;
89
90 switch (bits) {
91 case 7:
92 cflag |= CS7;
93 break;
94 default:
95 case 8:
96 cflag |= CS8;
97 break;
98 }
99 switch (parity) {
100 case 'o': case 'O':
101 cflag |= PARODD;
102 break;
103 case 'e': case 'E':
104 cflag |= PARENB;
105 break;
106 }
107 co->cflag = cflag;
108
109 /*
110 * no need to check the index here: if the index is wrong, console
111 * code won't call us
112 */
113 serial = usb_serial_get_by_index(co->index);
114 if (serial == NULL) {
115 /* no device is connected yet, sorry :( */
116 err("No USB device connected to ttyUSB%i", co->index);
117 return -ENODEV;
118 }
119
120 retval = usb_autopm_get_interface(serial->interface);
121 if (retval)
122 goto error_get_interface;
123
124 port = serial->port[co->index - serial->minor];
125 tty_port_tty_set(&port->port, NULL);
126
127 info->port = port;
128
129 ++port->port.count;
130 if (!test_bit(ASYNCB_INITIALIZED, &port->port.flags)) {
131 if (serial->type->set_termios) {
132 /*
133 * allocate a fake tty so the driver can initialize
134 * the termios structure, then later call set_termios to
135 * configure according to command line arguments
136 */
137 tty = kzalloc(sizeof(*tty), GFP_KERNEL);
138 if (!tty) {
139 retval = -ENOMEM;
140 err("no more memory");
141 goto reset_open_count;
142 }
143 kref_init(&tty->kref);
144 tty_port_tty_set(&port->port, tty);
145 tty->driver = usb_serial_tty_driver;
146 tty->index = co->index;
147 if (tty_init_termios(tty)) {
148 retval = -ENOMEM;
149 err("no more memory");
150 goto free_tty;
151 }
152 }
153
154 /* only call the device specific open if this
155 * is the first time the port is opened */
156 if (serial->type->open)
157 retval = serial->type->open(NULL, port);
158 else
159 retval = usb_serial_generic_open(NULL, port);
160
161 if (retval) {
162 err("could not open USB console port");
163 goto fail;
164 }
165
166 if (serial->type->set_termios) {
167 tty->termios->c_cflag = cflag;
168 tty_termios_encode_baud_rate(tty->termios, baud, baud);
169 memset(&dummy, 0, sizeof(struct ktermios));
170 serial->type->set_termios(tty, port, &dummy);
171
172 tty_port_tty_set(&port->port, NULL);
173 kfree(tty);
174 }
175 set_bit(ASYNCB_INITIALIZED, &port->port.flags);
176 }
177 /* Now that any required fake tty operations are completed restore
178 * the tty port count */
179 --port->port.count;
180 /* The console is special in terms of closing the device so
181 * indicate this port is now acting as a system console. */
182 port->port.console = 1;
183
184 mutex_unlock(&serial->disc_mutex);
185 return retval;
186
187 fail:
188 tty_port_tty_set(&port->port, NULL);
189 free_tty:
190 kfree(tty);
191 reset_open_count:
192 port->port.count = 0;
193 usb_autopm_put_interface(serial->interface);
194 error_get_interface:
195 usb_serial_put(serial);
196 mutex_unlock(&serial->disc_mutex);
197 return retval;
198}
199
200static void usb_console_write(struct console *co,
201 const char *buf, unsigned count)
202{
203 static struct usbcons_info *info = &usbcons_info;
204 struct usb_serial_port *port = info->port;
205 struct usb_serial *serial;
206 int retval = -ENODEV;
207
208 if (!port || port->serial->dev->state == USB_STATE_NOTATTACHED)
209 return;
210 serial = port->serial;
211
212 if (count == 0)
213 return;
214
215 dbg("%s - port %d, %d byte(s)", __func__, port->number, count);
216
217 if (!port->port.console) {
218 dbg("%s - port not opened", __func__);
219 return;
220 }
221
222 while (count) {
223 unsigned int i;
224 unsigned int lf;
225 /* search for LF so we can insert CR if necessary */
226 for (i = 0, lf = 0 ; i < count ; i++) {
227 if (*(buf + i) == 10) {
228 lf = 1;
229 i++;
230 break;
231 }
232 }
233 /* pass on to the driver specific version of this function if
234 it is available */
235 if (serial->type->write)
236 retval = serial->type->write(NULL, port, buf, i);
237 else
238 retval = usb_serial_generic_write(NULL, port, buf, i);
239 dbg("%s - return value : %d", __func__, retval);
240 if (lf) {
241 /* append CR after LF */
242 unsigned char cr = 13;
243 if (serial->type->write)
244 retval = serial->type->write(NULL,
245 port, &cr, 1);
246 else
247 retval = usb_serial_generic_write(NULL,
248 port, &cr, 1);
249 dbg("%s - return value : %d", __func__, retval);
250 }
251 buf += i;
252 count -= i;
253 }
254}
255
256static struct tty_driver *usb_console_device(struct console *co, int *index)
257{
258 struct tty_driver **p = (struct tty_driver **)co->data;
259
260 if (!*p)
261 return NULL;
262
263 *index = co->index;
264 return *p;
265}
266
267static struct console usbcons = {
268 .name = "ttyUSB",
269 .write = usb_console_write,
270 .device = usb_console_device,
271 .setup = usb_console_setup,
272 .flags = CON_PRINTBUFFER,
273 .index = -1,
274 .data = &usb_serial_tty_driver,
275};
276
277void usb_serial_console_disconnect(struct usb_serial *serial)
278{
279 if (serial && serial->port && serial->port[0]
280 && serial->port[0] == usbcons_info.port) {
281 usb_serial_console_exit();
282 usb_serial_put(serial);
283 }
284}
285
286void usb_serial_console_init(int serial_debug, int minor)
287{
288 debug = serial_debug;
289
290 if (minor == 0) {
291 /*
292 * Call register_console() if this is the first device plugged
293 * in. If we call it earlier, then the callback to
294 * console_setup() will fail, as there is not a device seen by
295 * the USB subsystem yet.
296 */
297 /*
298 * Register console.
299 * NOTES:
300 * console_setup() is called (back) immediately (from
301 * register_console). console_write() is called immediately
302 * from register_console iff CON_PRINTBUFFER is set in flags.
303 */
304 dbg("registering the USB serial console.");
305 register_console(&usbcons);
306 }
307}
308
309void usb_serial_console_exit(void)
310{
311 if (usbcons_info.port) {
312 unregister_console(&usbcons);
313 usbcons_info.port->port.console = 0;
314 usbcons_info.port = NULL;
315 }
316}
317