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 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                 printk(KERN_ERR "No USB device connected to ttyUSB%i\n",
 117                        co->index);
 118                 return -ENODEV;
 119         }
 120
 121         retval = usb_autopm_get_interface(serial->interface);
 122         if (retval)
 123                 goto error_get_interface;
 124
 125         port = serial->port[co->index - serial->minor];
 126         tty_port_tty_set(&port->port, NULL);
 127
 128         info->port = port;
 129
 130         ++port->port.count;
 131         if (!test_bit(ASYNCB_INITIALIZED, &port->port.flags)) {
 132                 if (serial->type->set_termios) {
 133                         /*
 134                          * allocate a fake tty so the driver can initialize
 135                          * the termios structure, then later call set_termios to
 136                          * configure according to command line arguments
 137                          */
 138                         tty = kzalloc(sizeof(*tty), GFP_KERNEL);
 139                         if (!tty) {
 140                                 retval = -ENOMEM;
 141                                 dev_err(&port->dev, "no more memory\n");
 142                                 goto reset_open_count;
 143                         }
 144                         kref_init(&tty->kref);
 145                         tty_port_tty_set(&port->port, tty);
 146                         tty->driver = usb_serial_tty_driver;
 147                         tty->index = co->index;
 148                         if (tty_init_termios(tty)) {
 149                                 retval = -ENOMEM;
 150                                 dev_err(&port->dev, "no more memory\n");
 151                                 goto free_tty;
 152                         }
 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                         dev_err(&port->dev, "could not open USB console port\n");
 164                         goto fail;
 165                 }
 166
 167                 if (serial->type->set_termios) {
 168                         tty->termios->c_cflag = cflag;
 169                         tty_termios_encode_baud_rate(tty->termios, baud, baud);
 170                         memset(&dummy, 0, sizeof(struct ktermios));
 171                         serial->type->set_termios(tty, port, &dummy);
 172
 173                         tty_port_tty_set(&port->port, NULL);
 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->port.console = 1;
 184
 185         mutex_unlock(&serial->disc_mutex);
 186         return retval;
 187
 188  fail:
 189         tty_port_tty_set(&port->port, NULL);
 190  free_tty:
 191         kfree(tty);
 192  reset_open_count:
 193         port->port.count = 0;
 194         usb_autopm_put_interface(serial->interface);
 195  error_get_interface:
 196         usb_serial_put(serial);
 197         mutex_unlock(&serial->disc_mutex);
 198         return retval;
 199 }
 200
 201 static void usb_console_write(struct console *co,
 202                                         const char *buf, unsigned count)
 203 {
 204         static struct usbcons_info *info = &usbcons_info;
 205         struct usb_serial_port *port = info->port;
 206         struct usb_serial *serial;
 207         int retval = -ENODEV;
 208
 209         if (!port || port->serial->dev->state == USB_STATE_NOTATTACHED)
 210                 return;
 211         serial = port->serial;
 212
 213         if (count == 0)
 214                 return;
 215
 216         dbg("%s - port %d, %d byte(s)", __func__, port->number, count);
 217
 218         if (!port->port.console) {
 219                 dbg("%s - port not opened", __func__);
 220                 return;
 221         }
 222
 223         while (count) {
 224                 unsigned int i;
 225                 unsigned int lf;
 226                 /* search for LF so we can insert CR if necessary */
 227                 for (i = 0, lf = 0 ; i < count ; i++) {
 228                         if (*(buf + i) == 10) {
 229                                 lf = 1;
 230                                 i++;
 231                                 break;
 232                         }
 233                 }
 234                 /* pass on to the driver specific version of this function if
 235                    it is available */
 236                 if (serial->type->write)
 237                         retval = serial->type->write(NULL, port, buf, i);
 238                 else
 239                         retval = usb_serial_generic_write(NULL, port, buf, i);
 240                 dbg("%s - return value : %d", __func__, retval);
 241                 if (lf) {
 242                         /* append CR after LF */
 243                         unsigned char cr = 13;
 244                         if (serial->type->write)
 245                                 retval = serial->type->write(NULL,
 246                                                                 port, &cr, 1);
 247                         else
 248                                 retval = usb_serial_generic_write(NULL,
 249                                                                 port, &cr, 1);
 250                         dbg("%s - return value : %d", __func__, retval);
 251                 }
 252                 buf += i;
 253                 count -= i;
 254         }
 255 }
 256
 257 static struct tty_driver *usb_console_device(struct console *co, int *index)
 258 {
 259         struct tty_driver **p = (struct tty_driver **)co->data;
 260
 261         if (!*p)
 262                 return NULL;
 263
 264         *index = co->index;
 265         return *p;
 266 }
 267
 268 static struct console usbcons = {
 269         .name =         "ttyUSB",
 270         .write =        usb_console_write,
 271         .device =       usb_console_device,
 272         .setup =        usb_console_setup,
 273         .flags =        CON_PRINTBUFFER,
 274         .index =        -1,
 275         .data =         &usb_serial_tty_driver,
 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                 usbcons_info.port->port.console = 0;
 315                 usbcons_info.port = NULL;
 316         }
 317 }
 318