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/config.h>
  15 #include <linux/kernel.h>
  16 #include <linux/init.h>
  17 #include <linux/slab.h>
  18 #include <linux/tty.h>
  19 #include <linux/console.h>
  20 #include <linux/usb.h>
  21
  22 static int debug;
  23
  24 #include "usb-serial.h"
  25
  26 struct usbcons_info {
  27         int                     magic;
  28         int                     break_flag;
  29         struct usb_serial_port  *port;
  30 };
  31
  32 static struct usbcons_info usbcons_info;
  33 static struct console usbcons;
  34
  35 /*
  36  * ------------------------------------------------------------
  37  * USB Serial console driver
  38  *
  39  * Much of the code here is copied from drivers/char/serial.c
  40  * and implements a phony serial console in the same way that
  41  * serial.c does so that in case some software queries it,
  42  * it will get the same results.
  43  *
  44  * Things that are different from the way the serial port code
  45  * does things, is that we call the lower level usb-serial
  46  * driver code to initialize the device, and we set the initial
  47  * console speeds based on the command line arguments.
  48  * ------------------------------------------------------------
  49  */
  50
  51
  52 /*
  53  * The parsing of the command line works exactly like the
  54  * serial.c code, except that the specifier is "ttyUSB" instead
  55  * of "ttyS".
  56  */
  57 static int __init usb_console_setup(struct console *co, char *options)
  58 {
  59         struct usbcons_info *info = &usbcons_info;
  60         int baud = 9600;
  61         int bits = 8;
  62         int parity = 'n';
  63         int doflow = 0;
  64         int cflag = CREAD | HUPCL | CLOCAL;
  65         char *s;
  66         struct usb_serial *serial;
  67         struct usb_serial_port *port;
  68         int retval = 0;
  69         struct tty_struct *tty;
  70         struct termios *termios;
  71
  72         dbg ("%s", __FUNCTION__);
  73
  74         if (options) {
  75                 baud = simple_strtoul(options, NULL, 10);
  76                 s = options;
  77                 while (*s >= '0' && *s <= '9')
  78                         s++;
  79                 if (*s)
  80                         parity = *s++;
  81                 if (*s)
  82                         bits   = *s++ - '0';
  83                 if (*s)
  84                         doflow = (*s++ == 'r');
  85         }
  86
  87         /* build a cflag setting */
  88         switch (baud) {
  89                 case 1200:
  90                         cflag |= B1200;
  91                         break;
  92                 case 2400:
  93                         cflag |= B2400;
  94                         break;
  95                 case 4800:
  96                         cflag |= B4800;
  97                         break;
  98                 case 19200:
  99                         cflag |= B19200;
 100                         break;
 101                 case 38400:
 102                         cflag |= B38400;
 103                         break;
 104                 case 57600:
 105                         cflag |= B57600;
 106                         break;
 107                 case 115200:
 108                         cflag |= B115200;
 109                         break;
 110                 case 9600:
 111                 default:
 112                         cflag |= B9600;
 113                         /*
 114                          * Set this to a sane value to prevent a divide error
 115                          */
 116                         baud  = 9600;
 117                         break;
 118         }
 119         switch (bits) {
 120                 case 7:
 121                         cflag |= CS7;
 122                         break;
 123                 default:
 124                 case 8:
 125                         cflag |= CS8;
 126                         break;
 127         }
 128         switch (parity) {
 129                 case 'o': case 'O':
 130                         cflag |= PARODD;
 131                         break;
 132                 case 'e': case 'E':
 133                         cflag |= PARENB;
 134                         break;
 135         }
 136         co->cflag = cflag;
 137
 138         /* grab the first serial port that happens to be connected */
 139         serial = usb_serial_get_by_index(0);
 140         if (serial == NULL) {
 141                 /* no device is connected yet, sorry :( */
 142                 err ("No USB device connected to ttyUSB0");
 143                 return -ENODEV;
 144         }
 145
 146         port = serial->port[0];
 147         port->tty = NULL;
 148
 149         info->port = port;
 150
 151         ++port->open_count;
 152         if (port->open_count == 1) {
 153                 /* only call the device specific open if this
 154                  * is the first time the port is opened */
 155                 if (serial->type->open)
 156                         retval = serial->type->open(port, NULL);
 157                 else
 158                         retval = usb_serial_generic_open(port, NULL);
 159                 if (retval)
 160                         port->open_count = 0;
 161         }
 162
 163         if (retval) {
 164                 err ("could not open USB console port");
 165                 return retval;
 166         }
 167
 168         if (serial->type->set_termios) {
 169                 /* build up a fake tty structure so that the open call has something
 170                  * to look at to get the cflag value */
 171                 tty = kmalloc (sizeof (*tty), GFP_KERNEL);
 172                 if (!tty) {
 173                         err ("no more memory");
 174                         return -ENOMEM;
 175                 }
 176                 termios = kmalloc (sizeof (*termios), GFP_KERNEL);
 177                 if (!termios) {
 178                         err ("no more memory");
 179                         kfree (tty);
 180                         return -ENOMEM;
 181                 }
 182                 memset (tty, 0x00, sizeof(*tty));
 183                 memset (termios, 0x00, sizeof(*termios));
 184                 termios->c_cflag = cflag;
 185                 tty->termios = termios;
 186                 port->tty = tty;
 187
 188                 /* set up the initial termios settings */
 189                 serial->type->set_termios(port, NULL);
 190                 port->tty = NULL;
 191                 kfree (termios);
 192                 kfree (tty);
 193         }
 194
 195         return retval;
 196 }
 197
 198 static void usb_console_write(struct console *co, 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)
 206                 return;
 207         serial = port->serial;
 208
 209         if (count == 0)
 210                 return;
 211
 212         dbg("%s - port %d, %d byte(s)", __FUNCTION__, port->number, count);
 213
 214         if (!port->open_count) {
 215                 dbg ("%s - port not opened", __FUNCTION__);
 216                 goto exit;
 217         }
 218
 219         /* pass on to the driver specific version of this function if it is available */
 220         if (serial->type->write)
 221                 retval = serial->type->write(port, buf, count);
 222         else
 223                 retval = usb_serial_generic_write(port, buf, count);
 224
 225 exit:
 226         dbg("%s - return value (if we had one): %d", __FUNCTION__, retval);
 227 }
 228
 229 static struct console usbcons = {
 230         .name =         "ttyUSB",
 231         .write =        usb_console_write,
 232         .setup =        usb_console_setup,
 233         .flags =        CON_PRINTBUFFER,
 234         .index =        -1,
 235 };
 236
 237 void usb_serial_console_init (int serial_debug, int minor)
 238 {
 239         debug = serial_debug;
 240
 241         if (minor == 0) {
 242                 /*
 243                  * Call register_console() if this is the first device plugged
 244                  * in.  If we call it earlier, then the callback to
 245                  * console_setup() will fail, as there is not a device seen by
 246                  * the USB subsystem yet.
 247                  */
 248                 /*
 249                  * Register console.
 250                  * NOTES:
 251                  * console_setup() is called (back) immediately (from register_console).
 252                  * console_write() is called immediately from register_console iff
 253                  * CON_PRINTBUFFER is set in flags.
 254                  */
 255                 dbg ("registering the USB serial console.");
 256                 register_console(&usbcons);
 257         }
 258 }
 259
 260 void usb_serial_console_exit (void)
 261 {
 262         unregister_console(&usbcons);
 263 }
 264