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         /* Sane default */
  86         if (baud == 0)
  87                 baud = 9600;
  88
  89         switch (bits) {
  90         case 7:
  91                 cflag |= CS7;
  92                 break;
  93         default:
  94         case 8:
  95                 cflag |= CS8;
  96                 break;
  97         }
  98         switch (parity) {
  99         case 'o': case 'O':
 100                 cflag |= PARODD;
 101                 break;
 102         case 'e': case 'E':
 103                 cflag |= PARENB;
 104                 break;
 105         }
 106         co->cflag = cflag;
 107
 108         /*
 109          * no need to check the index here: if the index is wrong, console
 110          * code won't call us
 111          */
 112         serial = usb_serial_get_by_index(co->index);
 113         if (serial == NULL) {
 114                 /* no device is connected yet, sorry :( */
 115                 err("No USB device connected to ttyUSB%i", co->index);
 116                 return -ENODEV;
 117         }
 118
 119         port = serial->port[0];
 120         tty_port_tty_set(&port->port, NULL);
 121
 122         info->port = port;
 123
 124         ++port->port.count;
 125         if (port->port.count == 1) {
 126                 if (serial->type->set_termios) {
 127                         /*
 128                          * allocate a fake tty so the driver can initialize
 129                          * the termios structure, then later call set_termios to
 130                          * configure according to command line arguments
 131                          */
 132                         tty = kzalloc(sizeof(*tty), GFP_KERNEL);
 133                         if (!tty) {
 134                                 retval = -ENOMEM;
 135                                 err("no more memory");
 136                                 goto reset_open_count;
 137                         }
 138                         kref_init(&tty->kref);
 139                         termios = kzalloc(sizeof(*termios), GFP_KERNEL);
 140                         if (!termios) {
 141                                 retval = -ENOMEM;
 142                                 err("no more memory");
 143                                 goto free_tty;
 144                         }
 145                         memset(&dummy, 0, sizeof(struct ktermios));
 146                         tty->termios = termios;
 147                         tty_port_tty_set(&port->port, tty);
 148                 }
 149
 150                 /* only call the device specific open if this
 151                  * is the first time the port is opened */
 152                 if (serial->type->open)
 153                         retval = serial->type->open(NULL, port, NULL);
 154                 else
 155                         retval = usb_serial_generic_open(NULL, port, NULL);
 156
 157                 if (retval) {
 158                         err("could not open USB console port");
 159                         goto free_termios;
 160                 }
 161
 162                 if (serial->type->set_termios) {
 163                         termios->c_cflag = cflag;
 164                         tty_termios_encode_baud_rate(termios, baud, baud);
 165                         serial->type->set_termios(tty, port, &dummy);
 166
 167                         tty_port_tty_set(&port->port, NULL);
 168                         kfree(termios);
 169                         kfree(tty);
 170                 }
 171         }
 172         /* Now that any required fake tty operations are completed restore
 173          * the tty port count */
 174         --port->port.count;
 175         /* The console is special in terms of closing the device so
 176          * indicate this port is now acting as a system console. */
 177         port->console = 1;
 178         retval = 0;
 179
 180 out:
 181         return retval;
 182 free_termios:
 183         kfree(termios);
 184         tty_port_tty_set(&port->port, NULL);
 185 free_tty:
 186         kfree(tty);
 187 reset_open_count:
 188         port->port.count = 0;
 189         goto out;
 190 }
 191
 192 static void usb_console_write(struct console *co,
 193                                         const char *buf, unsigned count)
 194 {
 195         static struct usbcons_info *info = &usbcons_info;
 196         struct usb_serial_port *port = info->port;
 197         struct usb_serial *serial;
 198         int retval = -ENODEV;
 199
 200         if (!port || port->serial->dev->state == USB_STATE_NOTATTACHED)
 201                 return;
 202         serial = port->serial;
 203
 204         if (count == 0)
 205                 return;
 206
 207         dbg("%s - port %d, %d byte(s)", __func__, port->number, count);
 208
 209         if (!port->console) {
 210                 dbg("%s - port not opened", __func__);
 211                 return;
 212         }
 213
 214         while (count) {
 215                 unsigned int i;
 216                 unsigned int lf;
 217                 /* search for LF so we can insert CR if necessary */
 218                 for (i = 0, lf = 0 ; i < count ; i++) {
 219                         if (*(buf + i) == 10) {
 220                                 lf = 1;
 221                                 i++;
 222                                 break;
 223                         }
 224                 }
 225                 /* pass on to the driver specific version of this function if
 226                    it is available */
 227                 if (serial->type->write)
 228                         retval = serial->type->write(NULL, port, buf, i);
 229                 else
 230                         retval = usb_serial_generic_write(NULL, port, buf, i);
 231                 dbg("%s - return value : %d", __func__, retval);
 232                 if (lf) {
 233                         /* append CR after LF */
 234                         unsigned char cr = 13;
 235                         if (serial->type->write)
 236                                 retval = serial->type->write(NULL,
 237                                                                 port, &cr, 1);
 238                         else
 239                                 retval = usb_serial_generic_write(NULL,
 240                                                                 port, &cr, 1);
 241                         dbg("%s - return value : %d", __func__, retval);
 242                 }
 243                 buf += i;
 244                 count -= i;
 245         }
 246 }
 247
 248 static struct tty_driver *usb_console_device(struct console *co, int *index)
 249 {
 250         struct tty_driver **p = (struct tty_driver **)co->data;
 251
 252         if (!*p)
 253                 return NULL;
 254
 255         *index = co->index;
 256         return *p;
 257 }
 258
 259 static struct console usbcons = {
 260         .name =         "ttyUSB",
 261         .write =        usb_console_write,
 262         .device =       usb_console_device,
 263         .setup =        usb_console_setup,
 264         .flags =        CON_PRINTBUFFER,
 265         .index =        -1,
 266         .data =         &usb_serial_tty_driver,
 267 };
 268
 269 void usb_serial_console_disconnect(struct usb_serial *serial)
 270 {
 271         if (serial && serial->port && serial->port[0]
 272                                 && serial->port[0] == usbcons_info.port) {
 273                 usb_serial_console_exit();
 274                 usb_serial_put(serial);
 275         }
 276 }
 277
 278 void usb_serial_console_init(int serial_debug, int minor)
 279 {
 280         debug = serial_debug;
 281
 282         if (minor == 0) {
 283                 /*
 284                  * Call register_console() if this is the first device plugged
 285                  * in.  If we call it earlier, then the callback to
 286                  * console_setup() will fail, as there is not a device seen by
 287                  * the USB subsystem yet.
 288                  */
 289                 /*
 290                  * Register console.
 291                  * NOTES:
 292                  * console_setup() is called (back) immediately (from
 293                  * register_console). console_write() is called immediately
 294                  * from register_console iff CON_PRINTBUFFER is set in flags.
 295                  */
 296                 dbg("registering the USB serial console.");
 297                 register_console(&usbcons);
 298         }
 299 }
 300
 301 void usb_serial_console_exit(void)
 302 {
 303         if (usbcons_info.port) {
 304                 unregister_console(&usbcons);
 305                 usbcons_info.port->console = 0;
 306                 usbcons_info.port = NULL;
 307         }
 308 }
 309