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 #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
  23 static int debug;
  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  */
  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 *termios = NULL, 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                         termios = kzalloc(sizeof(*termios), GFP_KERNEL);
 145                         if (!termios) {
 146                                 retval = -ENOMEM;
 147                                 err("no more memory");
 148                                 goto free_tty;
 149                         }
 150                         memset(&dummy, 0, sizeof(struct ktermios));
 151                         tty->termios = termios;
 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                 if (serial->type->open)
 158                         retval = serial->type->open(NULL, port);
 159                 else
 160                         retval = usb_serial_generic_open(NULL, port);
 161
 162                 if (retval) {
 163                         err("could not open USB console port");
 164                         goto free_termios;
 165                 }
 166
 167                 if (serial->type->set_termios) {
 168                         termios->c_cflag = cflag;
 169                         tty_termios_encode_baud_rate(termios, baud, baud);
 170                         serial->type->set_termios(tty, port, &dummy);
 171
 172                         tty_port_tty_set(&port->port, NULL);
 173                         kfree(termios);
 174                         kfree(tty);
 175                 }
 176                 set_bit(ASYNCB_INITIALIZED, &port->port.flags);
 177         }
 178         /* Now that any required fake tty operations are completed restore
 179          * the tty port count */
 180         --port->port.count;
 181         /* The console is special in terms of closing the device so
 182          * indicate this port is now acting as a system console. */
 183         port->console = 1;
 184
 185         mutex_unlock(&serial->disc_mutex);
 186         return retval;
 187
 188  free_termios:
 189         kfree(termios);
 190         tty_port_tty_set(&port->port, NULL);
 191  free_tty:
 192         kfree(tty);
 193  reset_open_count:
 194         port->port.count = 0;
 195         usb_autopm_put_interface(serial->interface);
 196  error_get_interface:
 197         usb_serial_put(serial);
 198         mutex_unlock(&serial->disc_mutex);
 199         return retval;
 200 }
 201
 202 static void usb_console_write(struct console *co,
 203                                         const char *buf, unsigned count)
 204 {
 205         static struct usbcons_info *info = &usbcons_info;
 206         struct usb_serial_port *port = info->port;
 207         struct usb_serial *serial;
 208         int retval = -ENODEV;
 209
 210         if (!port || port->serial->dev->state == USB_STATE_NOTATTACHED)
 211                 return;
 212         serial = port->serial;
 213
 214         if (count == 0)
 215                 return;
 216
 217         dbg("%s - port %d, %d byte(s)", __func__, port->number, count);
 218
 219         if (!port->console) {
 220                 dbg("%s - port not opened", __func__);
 221                 return;
 222         }
 223
 224         while (count) {
 225                 unsigned int i;
 226                 unsigned int lf;
 227                 /* search for LF so we can insert CR if necessary */
 228                 for (i = 0, lf = 0 ; i < count ; i++) {
 229                         if (*(buf + i) == 10) {
 230                                 lf = 1;
 231                                 i++;
 232                                 break;
 233                         }
 234                 }
 235                 /* pass on to the driver specific version of this function if
 236                    it is available */
 237                 if (serial->type->write)
 238                         retval = serial->type->write(NULL, port, buf, i);
 239                 else
 240                         retval = usb_serial_generic_write(NULL, port, buf, i);
 241                 dbg("%s - return value : %d", __func__, retval);
 242                 if (lf) {
 243                         /* append CR after LF */
 244                         unsigned char cr = 13;
 245                         if (serial->type->write)
 246                                 retval = serial->type->write(NULL,
 247                                                                 port, &cr, 1);
 248                         else
 249                                 retval = usb_serial_generic_write(NULL,
 250                                                                 port, &cr, 1);
 251                         dbg("%s - return value : %d", __func__, retval);
 252                 }
 253                 buf += i;
 254                 count -= i;
 255         }
 256 }
 257
 258 static struct tty_driver *usb_console_device(struct console *co, int *index)
 259 {
 260         struct tty_driver **p = (struct tty_driver **)co->data;
 261
 262         if (!*p)
 263                 return NULL;
 264
 265         *index = co->index;
 266         return *p;
 267 }
 268
 269 static struct console usbcons = {
 270         .name =         "ttyUSB",
 271         .write =        usb_console_write,
 272         .device =       usb_console_device,
 273         .setup =        usb_console_setup,
 274         .flags =        CON_PRINTBUFFER,
 275         .index =        -1,
 276         .data =         &usb_serial_tty_driver,
 277 };
 278
 279 void usb_serial_console_disconnect(struct usb_serial *serial)
 280 {
 281         if (serial && serial->port && serial->port[0]
 282                                 && serial->port[0] == usbcons_info.port) {
 283                 usb_serial_console_exit();
 284                 usb_serial_put(serial);
 285         }
 286 }
 287
 288 void usb_serial_console_init(int serial_debug, int minor)
 289 {
 290         debug = serial_debug;
 291
 292         if (minor == 0) {
 293                 /*
 294                  * Call register_console() if this is the first device plugged
 295                  * in.  If we call it earlier, then the callback to
 296                  * console_setup() will fail, as there is not a device seen by
 297                  * the USB subsystem yet.
 298                  */
 299                 /*
 300                  * Register console.
 301                  * NOTES:
 302                  * console_setup() is called (back) immediately (from
 303                  * register_console). console_write() is called immediately
 304                  * from register_console iff CON_PRINTBUFFER is set in flags.
 305                  */
 306                 dbg("registering the USB serial console.");
 307                 register_console(&usbcons);
 308         }
 309 }
 310
 311 void usb_serial_console_exit(void)
 312 {
 313         if (usbcons_info.port) {
 314                 unregister_console(&usbcons);
 315                 usbcons_info.port->console = 0;
 316                 usbcons_info.port = NULL;
 317         }
 318 }
 319