Merge tag 'trace-v4.11-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt...
[sfrench/cifs-2.6.git] / drivers / usb / serial / console.c
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/module.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 static const struct tty_operations usb_console_fake_tty_ops = {
51 };
52
53 /*
54  * The parsing of the command line works exactly like the
55  * serial.c code, except that the specifier is "ttyUSB" instead
56  * of "ttyS".
57  */
58 static int usb_console_setup(struct console *co, char *options)
59 {
60         struct usbcons_info *info = &usbcons_info;
61         int baud = 9600;
62         int bits = 8;
63         int parity = 'n';
64         int doflow = 0;
65         int cflag = CREAD | HUPCL | CLOCAL;
66         char *s;
67         struct usb_serial *serial;
68         struct usb_serial_port *port;
69         int retval;
70         struct tty_struct *tty = NULL;
71         struct ktermios dummy;
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         port = usb_serial_port_get_by_minor(co->index);
114         if (port == NULL) {
115                 /* no device is connected yet, sorry :( */
116                 pr_err("No USB device connected to ttyUSB%i\n", co->index);
117                 return -ENODEV;
118         }
119         serial = port->serial;
120
121         retval = usb_autopm_get_interface(serial->interface);
122         if (retval)
123                 goto error_get_interface;
124
125         tty_port_tty_set(&port->port, NULL);
126
127         info->port = port;
128
129         ++port->port.count;
130         if (!tty_port_initialized(&port->port)) {
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                                 goto reset_open_count;
141                         }
142                         kref_init(&tty->kref);
143                         tty->driver = usb_serial_tty_driver;
144                         tty->index = co->index;
145                         init_ldsem(&tty->ldisc_sem);
146                         spin_lock_init(&tty->files_lock);
147                         INIT_LIST_HEAD(&tty->tty_files);
148                         kref_get(&tty->driver->kref);
149                         __module_get(tty->driver->owner);
150                         tty->ops = &usb_console_fake_tty_ops;
151                         tty_init_termios(tty);
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                 tty_port_set_initialized(&port->port, 1);
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         usb_autopm_put_interface(serial->interface);
190  error_get_interface:
191         usb_serial_put(serial);
192         mutex_unlock(&serial->disc_mutex);
193         return retval;
194 }
195
196 static void usb_console_write(struct console *co,
197                                         const char *buf, unsigned count)
198 {
199         static struct usbcons_info *info = &usbcons_info;
200         struct usb_serial_port *port = info->port;
201         struct usb_serial *serial;
202         int retval = -ENODEV;
203
204         if (!port || port->serial->dev->state == USB_STATE_NOTATTACHED)
205                 return;
206         serial = port->serial;
207
208         if (count == 0)
209                 return;
210
211         dev_dbg(&port->dev, "%s - %d byte(s)\n", __func__, count);
212
213         if (!port->port.console) {
214                 dev_dbg(&port->dev, "%s - port not opened\n", __func__);
215                 return;
216         }
217
218         while (count) {
219                 unsigned int i;
220                 unsigned int lf;
221                 /* search for LF so we can insert CR if necessary */
222                 for (i = 0, lf = 0 ; i < count ; i++) {
223                         if (*(buf + i) == 10) {
224                                 lf = 1;
225                                 i++;
226                                 break;
227                         }
228                 }
229                 /* pass on to the driver specific version of this function if
230                    it is available */
231                 retval = serial->type->write(NULL, port, buf, i);
232                 dev_dbg(&port->dev, "%s - write: %d\n", __func__, retval);
233                 if (lf) {
234                         /* append CR after LF */
235                         unsigned char cr = 13;
236                         retval = serial->type->write(NULL, port, &cr, 1);
237                         dev_dbg(&port->dev, "%s - write cr: %d\n",
238                                                         __func__, retval);
239                 }
240                 buf += i;
241                 count -= i;
242         }
243 }
244
245 static struct tty_driver *usb_console_device(struct console *co, int *index)
246 {
247         struct tty_driver **p = (struct tty_driver **)co->data;
248
249         if (!*p)
250                 return NULL;
251
252         *index = co->index;
253         return *p;
254 }
255
256 static struct console usbcons = {
257         .name =         "ttyUSB",
258         .write =        usb_console_write,
259         .device =       usb_console_device,
260         .setup =        usb_console_setup,
261         .flags =        CON_PRINTBUFFER,
262         .index =        -1,
263         .data =         &usb_serial_tty_driver,
264 };
265
266 void usb_serial_console_disconnect(struct usb_serial *serial)
267 {
268         if (serial->port[0] == usbcons_info.port) {
269                 usb_serial_console_exit();
270                 usb_serial_put(serial);
271         }
272 }
273
274 void usb_serial_console_init(int minor)
275 {
276         if (minor == 0) {
277                 /*
278                  * Call register_console() if this is the first device plugged
279                  * in.  If we call it earlier, then the callback to
280                  * console_setup() will fail, as there is not a device seen by
281                  * the USB subsystem yet.
282                  */
283                 /*
284                  * Register console.
285                  * NOTES:
286                  * console_setup() is called (back) immediately (from
287                  * register_console). console_write() is called immediately
288                  * from register_console iff CON_PRINTBUFFER is set in flags.
289                  */
290                 pr_debug("registering the USB serial console.\n");
291                 register_console(&usbcons);
292         }
293 }
294
295 void usb_serial_console_exit(void)
296 {
297         if (usbcons_info.port) {
298                 unregister_console(&usbcons);
299                 usbcons_info.port->port.console = 0;
300                 usbcons_info.port = NULL;
301         }
302 }
303