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 = NULL;
  68         struct ktermios *termios = NULL, dummy;
  69
  70         dbg("%s", __func__);
  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         /*
 137          * no need to check the index here: if the index is wrong, console
 138          * code won't call us
 139          */
 140         serial = usb_serial_get_by_index(co->index);
 141         if (serial == NULL) {
 142                 /* no device is connected yet, sorry :( */
 143                 err("No USB device connected to ttyUSB%i", co->index);
 144                 return -ENODEV;
 145         }
 146
 147         port = serial->port[0];
 148         port->port.tty = NULL;
 149
 150         info->port = port;
 151
 152         ++port->port.count;
 153         if (port->port.count == 1) {
 154                 if (serial->type->set_termios) {
 155                         /*
 156                          * allocate a fake tty so the driver can initialize
 157                          * the termios structure, then later call set_termios to
 158                          * configure according to command line arguments
 159                          */
 160                         tty = kzalloc(sizeof(*tty), GFP_KERNEL);
 161                         if (!tty) {
 162                                 retval = -ENOMEM;
 163                                 err("no more memory");
 164                                 goto reset_open_count;
 165                         }
 166                         termios = kzalloc(sizeof(*termios), GFP_KERNEL);
 167                         if (!termios) {
 168                                 retval = -ENOMEM;
 169                                 err("no more memory");
 170                                 goto free_tty;
 171                         }
 172                         memset(&dummy, 0, sizeof(struct ktermios));
 173                         tty->termios = termios;
 174                         port->port.tty = tty;
 175                 }
 176
 177                 /* only call the device specific open if this
 178                  * is the first time the port is opened */
 179                 if (serial->type->open)
 180                         retval = serial->type->open(NULL, port, NULL);
 181                 else
 182                         retval = usb_serial_generic_open(NULL, port, NULL);
 183
 184                 if (retval) {
 185                         err("could not open USB console port");
 186                         goto free_termios;
 187                 }
 188
 189                 if (serial->type->set_termios) {
 190                         termios->c_cflag = cflag;
 191                         serial->type->set_termios(NULL, port, &dummy);
 192
 193                         port->port.tty = NULL;
 194                         kfree(termios);
 195                         kfree(tty);
 196                 }
 197         }
 198
 199         port->console = 1;
 200         retval = 0;
 201
 202 out:
 203         return retval;
 204 free_termios:
 205         kfree(termios);
 206         port->port.tty = NULL;
 207 free_tty:
 208         kfree(tty);
 209 reset_open_count:
 210         port->port.count = 0;
 211 goto out;
 212 }
 213
 214 static void usb_console_write(struct console *co,
 215                                         const char *buf, unsigned count)
 216 {
 217         static struct usbcons_info *info = &usbcons_info;
 218         struct usb_serial_port *port = info->port;
 219         struct usb_serial *serial;
 220         int retval = -ENODEV;
 221
 222         if (!port || port->serial->dev->state == USB_STATE_NOTATTACHED)
 223                 return;
 224         serial = port->serial;
 225
 226         if (count == 0)
 227                 return;
 228
 229         dbg("%s - port %d, %d byte(s)", __func__, port->number, count);
 230
 231         if (!port->port.count) {
 232                 dbg("%s - port not opened", __func__);
 233                 return;
 234         }
 235
 236         while (count) {
 237                 unsigned int i;
 238                 unsigned int lf;
 239                 /* search for LF so we can insert CR if necessary */
 240                 for (i = 0, lf = 0 ; i < count ; i++) {
 241                         if (*(buf + i) == 10) {
 242                                 lf = 1;
 243                                 i++;
 244                                 break;
 245                         }
 246                 }
 247                 /* pass on to the driver specific version of this function if
 248                    it is available */
 249                 if (serial->type->write)
 250                         retval = serial->type->write(NULL, port, buf, i);
 251                 else
 252                         retval = usb_serial_generic_write(NULL, port, buf, i);
 253                 dbg("%s - return value : %d", __func__, retval);
 254                 if (lf) {
 255                         /* append CR after LF */
 256                         unsigned char cr = 13;
 257                         if (serial->type->write)
 258                                 retval = serial->type->write(NULL,
 259                                                                 port, &cr, 1);
 260                         else
 261                                 retval = usb_serial_generic_write(NULL,
 262                                                                 port, &cr, 1);
 263                         dbg("%s - return value : %d", __func__, retval);
 264                 }
 265                 buf += i;
 266                 count -= i;
 267         }
 268 }
 269
 270 static struct console usbcons = {
 271         .name =         "ttyUSB",
 272         .write =        usb_console_write,
 273         .setup =        usb_console_setup,
 274         .flags =        CON_PRINTBUFFER,
 275         .index =        -1,
 276 };
 277
 278 void usb_serial_console_disconnect(struct usb_serial *serial)
 279 {
 280         if (serial && serial->port && serial->port[0]
 281                                 && serial->port[0] == usbcons_info.port) {
 282                 usb_serial_console_exit();
 283                 usb_serial_put(serial);
 284         }
 285 }
 286
 287 void usb_serial_console_init(int serial_debug, int minor)
 288 {
 289         debug = serial_debug;
 290
 291         if (minor == 0) {
 292                 /*
 293                  * Call register_console() if this is the first device plugged
 294                  * in.  If we call it earlier, then the callback to
 295                  * console_setup() will fail, as there is not a device seen by
 296                  * the USB subsystem yet.
 297                  */
 298                 /*
 299                  * Register console.
 300                  * NOTES:
 301                  * console_setup() is called (back) immediately (from
 302                  * register_console). console_write() is called immediately
 303                  * from register_console iff CON_PRINTBUFFER is set in flags.
 304                  */
 305                 dbg("registering the USB serial console.");
 306                 register_console(&usbcons);
 307         }
 308 }
 309
 310 void usb_serial_console_exit(void)
 311 {
 312         if (usbcons_info.port) {
 313                 unregister_console(&usbcons);
 314                 if (usbcons_info.port->port.count)
 315                         usbcons_info.port->port.count--;
 316                 usbcons_info.port = NULL;
 317         }
 318 }
 319