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/usb.h>
  20 #include <linux/usb/serial.h>
  21
  22 static int debug;
  23
  24 struct usbcons_info {
  25         int                     magic;
  26         int                     break_flag;
  27         struct usb_serial_port  *port;
  28 };
  29
  30 static struct usbcons_info usbcons_info;
  31 static 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  */
  55 static 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 = 0;
  67         struct tty_struct *tty;
  68         struct ktermios *termios;
  69
  70         dbg ("%s", __FUNCTION__);
  71
  72         if (options) {
  73                 baud = simple_strtoul(options, NULL, 10);
  74                 s = options;
  75                 while (*s >= '0' && *s <= '9')
  76                         s++;
  77                 if (*s)
  78                         parity = *s++;
  79                 if (*s)
  80                         bits   = *s++ - '0';
  81                 if (*s)
  82                         doflow = (*s++ == 'r');
  83         }
  84
  85         /* build a cflag setting */
  86         switch (baud) {
  87                 case 1200:
  88                         cflag |= B1200;
  89                         break;
  90                 case 2400:
  91                         cflag |= B2400;
  92                         break;
  93                 case 4800:
  94                         cflag |= B4800;
  95                         break;
  96                 case 19200:
  97                         cflag |= B19200;
  98                         break;
  99                 case 38400:
 100                         cflag |= B38400;
 101                         break;
 102                 case 57600:
 103                         cflag |= B57600;
 104                         break;
 105                 case 115200:
 106                         cflag |= B115200;
 107                         break;
 108                 case 9600:
 109                 default:
 110                         cflag |= B9600;
 111                         /*
 112                          * Set this to a sane value to prevent a divide error
 113                          */
 114                         baud  = 9600;
 115                         break;
 116         }
 117         switch (bits) {
 118                 case 7:
 119                         cflag |= CS7;
 120                         break;
 121                 default:
 122                 case 8:
 123                         cflag |= CS8;
 124                         break;
 125         }
 126         switch (parity) {
 127                 case 'o': case 'O':
 128                         cflag |= PARODD;
 129                         break;
 130                 case 'e': case 'E':
 131                         cflag |= PARENB;
 132                         break;
 133         }
 134         co->cflag = cflag;
 135
 136         /* grab the first serial port that happens to be connected */
 137         serial = usb_serial_get_by_index(0);
 138         if (serial == NULL) {
 139                 /* no device is connected yet, sorry :( */
 140                 err ("No USB device connected to ttyUSB0");
 141                 return -ENODEV;
 142         }
 143
 144         port = serial->port[0];
 145         port->tty = NULL;
 146
 147         info->port = port;
 148
 149         ++port->open_count;
 150         if (port->open_count == 1) {
 151                 /* only call the device specific open if this
 152                  * is the first time the port is opened */
 153                 if (serial->type->open)
 154                         retval = serial->type->open(port, NULL);
 155                 else
 156                         retval = usb_serial_generic_open(port, NULL);
 157                 if (retval)
 158                         port->open_count = 0;
 159         }
 160
 161         if (retval) {
 162                 err ("could not open USB console port");
 163                 return retval;
 164         }
 165
 166         if (serial->type->set_termios) {
 167                 struct ktermios dummy;
 168                 /* build up a fake tty structure so that the open call has something
 169                  * to look at to get the cflag value */
 170                 tty = kzalloc(sizeof(*tty), GFP_KERNEL);
 171                 if (!tty) {
 172                         err ("no more memory");
 173                         return -ENOMEM;
 174                 }
 175                 termios = kzalloc(sizeof(*termios), GFP_KERNEL);
 176                 if (!termios) {
 177                         err ("no more memory");
 178                         kfree (tty);
 179                         return -ENOMEM;
 180                 }
 181                 memset(&dummy, 0, sizeof(struct ktermios));
 182                 termios->c_cflag = cflag;
 183                 tty->termios = termios;
 184                 port->tty = tty;
 185
 186                 /* set up the initial termios settings */
 187                 serial->type->set_termios(port, &dummy);
 188                 port->tty = NULL;
 189                 kfree (termios);
 190                 kfree (tty);
 191         }
 192
 193         return retval;
 194 }
 195
 196 static void usb_console_write(struct console *co, const char *buf, unsigned count)
 197 {
 198         static struct usbcons_info *info = &usbcons_info;
 199         struct usb_serial_port *port = info->port;
 200         struct usb_serial *serial;
 201         int retval = -ENODEV;
 202
 203         if (!port || port->serial->dev->state == USB_STATE_NOTATTACHED)
 204                 return;
 205         serial = port->serial;
 206
 207         if (count == 0)
 208                 return;
 209
 210         dbg("%s - port %d, %d byte(s)", __FUNCTION__, port->number, count);
 211
 212         if (!port->open_count) {
 213                 dbg ("%s - port not opened", __FUNCTION__);
 214                 return;
 215         }
 216
 217         while (count) {
 218                 unsigned int i;
 219                 unsigned int lf;
 220                 /* search for LF so we can insert CR if necessary */
 221                 for (i=0, lf=0 ; i < count ; i++) {
 222                         if (*(buf + i) == 10) {
 223                                 lf = 1;
 224                                 i++;
 225                                 break;
 226                         }
 227                 }
 228                 /* pass on to the driver specific version of this function if it is available */
 229                 if (serial->type->write)
 230                         retval = serial->type->write(port, buf, i);
 231                 else
 232                         retval = usb_serial_generic_write(port, buf, i);
 233                 dbg("%s - return value : %d", __FUNCTION__, retval);
 234                 if (lf) {
 235                         /* append CR after LF */
 236                         unsigned char cr = 13;
 237                         if (serial->type->write)
 238                                 retval = serial->type->write(port, &cr, 1);
 239                         else
 240                                 retval = usb_serial_generic_write(port, &cr, 1);
 241                         dbg("%s - return value : %d", __FUNCTION__, retval);
 242                 }
 243                 buf += i;
 244                 count -= i;
 245         }
 246 }
 247
 248 static struct console usbcons = {
 249         .name =         "ttyUSB",
 250         .write =        usb_console_write,
 251         .setup =        usb_console_setup,
 252         .flags =        CON_PRINTBUFFER,
 253         .index =        -1,
 254 };
 255
 256 void usb_serial_console_disconnect(struct usb_serial *serial)
 257 {
 258         if (serial && serial->port && serial->port[0] && serial->port[0] == usbcons_info.port) {
 259                 usb_serial_console_exit();
 260                 usb_serial_put(serial);
 261         }
 262 }
 263
 264 void usb_serial_console_init (int serial_debug, int minor)
 265 {
 266         debug = serial_debug;
 267
 268         if (minor == 0) {
 269                 /*
 270                  * Call register_console() if this is the first device plugged
 271                  * in.  If we call it earlier, then the callback to
 272                  * console_setup() will fail, as there is not a device seen by
 273                  * the USB subsystem yet.
 274                  */
 275                 /*
 276                  * Register console.
 277                  * NOTES:
 278                  * console_setup() is called (back) immediately (from register_console).
 279                  * console_write() is called immediately from register_console iff
 280                  * CON_PRINTBUFFER is set in flags.
 281                  */
 282                 dbg ("registering the USB serial console.");
 283                 register_console(&usbcons);
 284         }
 285 }
 286
 287 void usb_serial_console_exit (void)
 288 {
 289         if (usbcons_info.port) {
 290                 unregister_console(&usbcons);
 291                 if (usbcons_info.port->open_count)
 292                         usbcons_info.port->open_count--;
 293                 usbcons_info.port = NULL;
 294         }
 295 }
 296