drivers/usb/serial/opticon.c

   1 /*
   2  * Opticon USB barcode to serial driver
   3  *
   4  * Copyright (C) 2008 - 2009 Greg Kroah-Hartman <gregkh@suse.de>
   5  * Copyright (C) 2008 - 2009 Novell Inc.
   6  *
   7  *      This program is free software; you can redistribute it and/or
   8  *      modify it under the terms of the GNU General Public License version
   9  *      2 as published by the Free Software Foundation.
  10  */
  11
  12 #include <linux/kernel.h>
  13 #include <linux/init.h>
  14 #include <linux/tty.h>
  15 #include <linux/tty_driver.h>
  16 #include <linux/tty_flip.h>
  17 #include <linux/module.h>
  18 #include <linux/usb.h>
  19 #include <linux/usb/serial.h>
  20 #include <linux/uaccess.h>
  21
  22 static int debug;
  23
  24 static struct usb_device_id id_table[] = {
  25         { USB_DEVICE(0x065a, 0x0009) },
  26         { },
  27 };
  28 MODULE_DEVICE_TABLE(usb, id_table);
  29
  30 /* This structure holds all of the individual device information */
  31 struct opticon_private {
  32         struct usb_device *udev;
  33         struct usb_serial *serial;
  34         struct usb_serial_port *port;
  35         unsigned char *bulk_in_buffer;
  36         struct urb *bulk_read_urb;
  37         int buffer_size;
  38         u8 bulk_address;
  39         spinlock_t lock;        /* protects the following flags */
  40         bool throttled;
  41         bool actually_throttled;
  42         bool rts;
  43         int outstanding_urbs;
  44 };
  45
  46 /* max number of write urbs in flight */
  47 #define URB_UPPER_LIMIT 4
  48
  49 static void opticon_bulk_callback(struct urb *urb)
  50 {
  51         struct opticon_private *priv = urb->context;
  52         unsigned char *data = urb->transfer_buffer;
  53         struct usb_serial_port *port = priv->port;
  54         int status = urb->status;
  55         struct tty_struct *tty;
  56         int result;
  57         int available_room = 0;
  58         int data_length;
  59
  60         dbg("%s - port %d", __func__, port->number);
  61
  62         switch (status) {
  63         case 0:
  64                 /* success */
  65                 break;
  66         case -ECONNRESET:
  67         case -ENOENT:
  68         case -ESHUTDOWN:
  69                 /* this urb is terminated, clean up */
  70                 dbg("%s - urb shutting down with status: %d",
  71                     __func__, status);
  72                 return;
  73         default:
  74                 dbg("%s - nonzero urb status received: %d",
  75                     __func__, status);
  76                 goto exit;
  77         }
  78
  79         usb_serial_debug_data(debug, &port->dev, __func__, urb->actual_length,
  80                               data);
  81
  82         if (urb->actual_length > 2) {
  83                 data_length = urb->actual_length - 2;
  84
  85                 /*
  86                  * Data from the device comes with a 2 byte header:
  87                  *
  88                  * <0x00><0x00>data...
  89                  *      This is real data to be sent to the tty layer
  90                  * <0x00><0x01)level
  91                  *      This is a RTS level change, the third byte is the RTS
  92                  *      value (0 for low, 1 for high).
  93                  */
  94                 if ((data[0] == 0x00) && (data[1] == 0x00)) {
  95                         /* real data, send it to the tty layer */
  96                         tty = tty_port_tty_get(&port->port);
  97                         if (tty) {
  98                                 available_room = tty_buffer_request_room(tty,
  99                                                                 data_length);
 100                                 if (available_room) {
 101                                         tty_insert_flip_string(tty, data,
 102                                                                available_room);
 103                                         tty_flip_buffer_push(tty);
 104                                 }
 105                                 tty_kref_put(tty);
 106                         }
 107                 } else {
 108                         if ((data[0] == 0x00) && (data[1] == 0x01)) {
 109                                 if (data[2] == 0x00)
 110                                         priv->rts = false;
 111                                 else
 112                                         priv->rts = true;
 113                                 /* FIXME change the RTS level */
 114                         } else {
 115                         dev_dbg(&priv->udev->dev,
 116                                 "Unknown data packet received from the device:"
 117                                 " %2x %2x\n",
 118                                 data[0], data[1]);
 119                         }
 120                 }
 121         } else {
 122                 dev_dbg(&priv->udev->dev,
 123                         "Improper ammount of data received from the device, "
 124                         "%d bytes", urb->actual_length);
 125         }
 126
 127 exit:
 128         spin_lock(&priv->lock);
 129
 130         /* Continue trying to always read if we should */
 131         if (!priv->throttled) {
 132                 usb_fill_bulk_urb(priv->bulk_read_urb, priv->udev,
 133                                   usb_rcvbulkpipe(priv->udev,
 134                                                   priv->bulk_address),
 135                                   priv->bulk_in_buffer, priv->buffer_size,
 136                                   opticon_bulk_callback, priv);
 137                 result = usb_submit_urb(port->read_urb, GFP_ATOMIC);
 138                 if (result)
 139                         dev_err(&port->dev,
 140                             "%s - failed resubmitting read urb, error %d\n",
 141                                                         __func__, result);
 142         } else
 143                 priv->actually_throttled = true;
 144         spin_unlock(&priv->lock);
 145 }
 146
 147 static int opticon_open(struct tty_struct *tty, struct usb_serial_port *port,
 148                         struct file *filp)
 149 {
 150         struct opticon_private *priv = usb_get_serial_data(port->serial);
 151         unsigned long flags;
 152         int result = 0;
 153
 154         dbg("%s - port %d", __func__, port->number);
 155
 156         spin_lock_irqsave(&priv->lock, flags);
 157         priv->throttled = false;
 158         priv->actually_throttled = false;
 159         priv->port = port;
 160         spin_unlock_irqrestore(&priv->lock, flags);
 161
 162         /*
 163          * Force low_latency on so that our tty_push actually forces the data
 164          * through, otherwise it is scheduled, and with high data rates (like
 165          * with OHCI) data can get lost.
 166          */
 167         if (tty)
 168                 tty->low_latency = 1;
 169
 170         /* Start reading from the device */
 171         usb_fill_bulk_urb(priv->bulk_read_urb, priv->udev,
 172                           usb_rcvbulkpipe(priv->udev,
 173                                           priv->bulk_address),
 174                           priv->bulk_in_buffer, priv->buffer_size,
 175                           opticon_bulk_callback, priv);
 176         result = usb_submit_urb(priv->bulk_read_urb, GFP_KERNEL);
 177         if (result)
 178                 dev_err(&port->dev,
 179                         "%s - failed resubmitting read urb, error %d\n",
 180                         __func__, result);
 181         return result;
 182 }
 183
 184 static void opticon_close(struct tty_struct *tty, struct usb_serial_port *port,
 185                           struct file *filp)
 186 {
 187         struct opticon_private *priv = usb_get_serial_data(port->serial);
 188
 189         dbg("%s - port %d", __func__, port->number);
 190
 191         /* shutdown our urbs */
 192         usb_kill_urb(priv->bulk_read_urb);
 193 }
 194
 195 static void opticon_write_bulk_callback(struct urb *urb)
 196 {
 197         struct opticon_private *priv = urb->context;
 198         int status = urb->status;
 199         unsigned long flags;
 200
 201         /* free up the transfer buffer, as usb_free_urb() does not do this */
 202         kfree(urb->transfer_buffer);
 203
 204         if (status)
 205                 dbg("%s - nonzero write bulk status received: %d",
 206                     __func__, status);
 207
 208         spin_lock_irqsave(&priv->lock, flags);
 209         --priv->outstanding_urbs;
 210         spin_unlock_irqrestore(&priv->lock, flags);
 211
 212         usb_serial_port_softint(priv->port);
 213 }
 214
 215 static int opticon_write(struct tty_struct *tty, struct usb_serial_port *port,
 216                          const unsigned char *buf, int count)
 217 {
 218         struct opticon_private *priv = usb_get_serial_data(port->serial);
 219         struct usb_serial *serial = port->serial;
 220         struct urb *urb;
 221         unsigned char *buffer;
 222         unsigned long flags;
 223         int status;
 224
 225         dbg("%s - port %d", __func__, port->number);
 226
 227         spin_lock_irqsave(&priv->lock, flags);
 228         if (priv->outstanding_urbs > URB_UPPER_LIMIT) {
 229                 spin_unlock_irqrestore(&priv->lock, flags);
 230                 dbg("%s - write limit hit\n", __func__);
 231                 return 0;
 232         }
 233         priv->outstanding_urbs++;
 234         spin_unlock_irqrestore(&priv->lock, flags);
 235
 236         buffer = kmalloc(count, GFP_ATOMIC);
 237         if (!buffer) {
 238                 dev_err(&port->dev, "out of memory\n");
 239                 count = -ENOMEM;
 240                 goto error_no_buffer;
 241         }
 242
 243         urb = usb_alloc_urb(0, GFP_ATOMIC);
 244         if (!urb) {
 245                 dev_err(&port->dev, "no more free urbs\n");
 246                 count = -ENOMEM;
 247                 goto error_no_urb;
 248         }
 249
 250         memcpy(buffer, buf, count);
 251
 252         usb_serial_debug_data(debug, &port->dev, __func__, count, buffer);
 253
 254         usb_fill_bulk_urb(urb, serial->dev,
 255                           usb_sndbulkpipe(serial->dev,
 256                                           port->bulk_out_endpointAddress),
 257                           buffer, count, opticon_write_bulk_callback, priv);
 258
 259         /* send it down the pipe */
 260         status = usb_submit_urb(urb, GFP_ATOMIC);
 261         if (status) {
 262                 dev_err(&port->dev,
 263                    "%s - usb_submit_urb(write bulk) failed with status = %d\n",
 264                                                         __func__, status);
 265                 count = status;
 266                 goto error;
 267         }
 268
 269         /* we are done with this urb, so let the host driver
 270          * really free it when it is finished with it */
 271         usb_free_urb(urb);
 272
 273         return count;
 274 error:
 275         usb_free_urb(urb);
 276 error_no_urb:
 277         kfree(buffer);
 278 error_no_buffer:
 279         spin_lock_irqsave(&priv->lock, flags);
 280         --priv->outstanding_urbs;
 281         spin_unlock_irqrestore(&priv->lock, flags);
 282         return count;
 283 }
 284
 285 static int opticon_write_room(struct tty_struct *tty)
 286 {
 287         struct usb_serial_port *port = tty->driver_data;
 288         struct opticon_private *priv = usb_get_serial_data(port->serial);
 289         unsigned long flags;
 290
 291         dbg("%s - port %d", __func__, port->number);
 292
 293         /*
 294          * We really can take almost anything the user throws at us
 295          * but let's pick a nice big number to tell the tty
 296          * layer that we have lots of free space, unless we don't.
 297          */
 298         spin_lock_irqsave(&priv->lock, flags);
 299         if (priv->outstanding_urbs > URB_UPPER_LIMIT * 2 / 3) {
 300                 spin_unlock_irqrestore(&priv->lock, flags);
 301                 dbg("%s - write limit hit\n", __func__);
 302                 return 0;
 303         }
 304         spin_unlock_irqrestore(&priv->lock, flags);
 305
 306         return 2048;
 307 }
 308
 309 static void opticon_throttle(struct tty_struct *tty)
 310 {
 311         struct usb_serial_port *port = tty->driver_data;
 312         struct opticon_private *priv = usb_get_serial_data(port->serial);
 313         unsigned long flags;
 314
 315         dbg("%s - port %d", __func__, port->number);
 316         spin_lock_irqsave(&priv->lock, flags);
 317         priv->throttled = true;
 318         spin_unlock_irqrestore(&priv->lock, flags);
 319 }
 320
 321
 322 static void opticon_unthrottle(struct tty_struct *tty)
 323 {
 324         struct usb_serial_port *port = tty->driver_data;
 325         struct opticon_private *priv = usb_get_serial_data(port->serial);
 326         unsigned long flags;
 327         int result;
 328
 329         dbg("%s - port %d", __func__, port->number);
 330
 331         spin_lock_irqsave(&priv->lock, flags);
 332         priv->throttled = false;
 333         priv->actually_throttled = false;
 334         spin_unlock_irqrestore(&priv->lock, flags);
 335
 336         priv->bulk_read_urb->dev = port->serial->dev;
 337         result = usb_submit_urb(priv->bulk_read_urb, GFP_ATOMIC);
 338         if (result)
 339                 dev_err(&port->dev,
 340                         "%s - failed submitting read urb, error %d\n",
 341                                                         __func__, result);
 342 }
 343
 344 static int opticon_startup(struct usb_serial *serial)
 345 {
 346         struct opticon_private *priv;
 347         struct usb_host_interface *intf;
 348         int i;
 349         int retval = -ENOMEM;
 350         bool bulk_in_found = false;
 351
 352         /* create our private serial structure */
 353         priv = kzalloc(sizeof(*priv), GFP_KERNEL);
 354         if (priv == NULL) {
 355                 dev_err(&serial->dev->dev, "%s - Out of memory\n", __func__);
 356                 return -ENOMEM;
 357         }
 358         spin_lock_init(&priv->lock);
 359         priv->serial = serial;
 360         priv->port = serial->port[0];
 361         priv->udev = serial->dev;
 362
 363         /* find our bulk endpoint */
 364         intf = serial->interface->altsetting;
 365         for (i = 0; i < intf->desc.bNumEndpoints; ++i) {
 366                 struct usb_endpoint_descriptor *endpoint;
 367
 368                 endpoint = &intf->endpoint[i].desc;
 369                 if (!usb_endpoint_is_bulk_in(endpoint))
 370                         continue;
 371
 372                 priv->bulk_read_urb = usb_alloc_urb(0, GFP_KERNEL);
 373                 if (!priv->bulk_read_urb) {
 374                         dev_err(&priv->udev->dev, "out of memory\n");
 375                         goto error;
 376                 }
 377
 378                 priv->buffer_size = le16_to_cpu(endpoint->wMaxPacketSize) * 2;
 379                 priv->bulk_in_buffer = kmalloc(priv->buffer_size, GFP_KERNEL);
 380                 if (!priv->bulk_in_buffer) {
 381                         dev_err(&priv->udev->dev, "out of memory\n");
 382                         goto error;
 383                 }
 384
 385                 priv->bulk_address = endpoint->bEndpointAddress;
 386
 387                 /* set up our bulk urb */
 388                 usb_fill_bulk_urb(priv->bulk_read_urb, priv->udev,
 389                                   usb_rcvbulkpipe(priv->udev,
 390                                                   endpoint->bEndpointAddress),
 391                                   priv->bulk_in_buffer, priv->buffer_size,
 392                                   opticon_bulk_callback, priv);
 393
 394                 bulk_in_found = true;
 395                 break;
 396                 }
 397
 398         if (!bulk_in_found) {
 399                 dev_err(&priv->udev->dev,
 400                         "Error - the proper endpoints were not found!\n");
 401                 goto error;
 402         }
 403
 404         usb_set_serial_data(serial, priv);
 405         return 0;
 406
 407 error:
 408         usb_free_urb(priv->bulk_read_urb);
 409         kfree(priv->bulk_in_buffer);
 410         kfree(priv);
 411         return retval;
 412 }
 413
 414 static void opticon_shutdown(struct usb_serial *serial)
 415 {
 416         struct opticon_private *priv = usb_get_serial_data(serial);
 417
 418         dbg("%s", __func__);
 419
 420         usb_kill_urb(priv->bulk_read_urb);
 421         usb_free_urb(priv->bulk_read_urb);
 422         kfree(priv->bulk_in_buffer);
 423         kfree(priv);
 424         usb_set_serial_data(serial, NULL);
 425 }
 426
 427 static int opticon_suspend(struct usb_interface *intf, pm_message_t message)
 428 {
 429         struct usb_serial *serial = usb_get_intfdata(intf);
 430         struct opticon_private *priv = usb_get_serial_data(serial);
 431
 432         usb_kill_urb(priv->bulk_read_urb);
 433         return 0;
 434 }
 435
 436 static int opticon_resume(struct usb_interface *intf)
 437 {
 438         struct usb_serial *serial = usb_get_intfdata(intf);
 439         struct opticon_private *priv = usb_get_serial_data(serial);
 440         struct usb_serial_port *port = serial->port[0];
 441         int result;
 442
 443         mutex_lock(&port->mutex);
 444         if (port->port.count)
 445                 result = usb_submit_urb(priv->bulk_read_urb, GFP_NOIO);
 446         else
 447                 result = 0;
 448         mutex_unlock(&port->mutex);
 449         return result;
 450 }
 451
 452 static struct usb_driver opticon_driver = {
 453         .name =         "opticon",
 454         .probe =        usb_serial_probe,
 455         .disconnect =   usb_serial_disconnect,
 456         .suspend =      opticon_suspend,
 457         .resume =       opticon_resume,
 458         .id_table =     id_table,
 459         .no_dynamic_id =        1,
 460 };
 461
 462 static struct usb_serial_driver opticon_device = {
 463         .driver = {
 464                 .owner =        THIS_MODULE,
 465                 .name =         "opticon",
 466         },
 467         .id_table =             id_table,
 468         .usb_driver =           &opticon_driver,
 469         .num_ports =            1,
 470         .attach =               opticon_startup,
 471         .open =                 opticon_open,
 472         .close =                opticon_close,
 473         .write =                opticon_write,
 474         .write_room =           opticon_write_room,
 475         .shutdown =             opticon_shutdown,
 476         .throttle =             opticon_throttle,
 477         .unthrottle =           opticon_unthrottle,
 478 };
 479
 480 static int __init opticon_init(void)
 481 {
 482         int retval;
 483
 484         retval = usb_serial_register(&opticon_device);
 485         if (retval)
 486                 return retval;
 487         retval = usb_register(&opticon_driver);
 488         if (retval)
 489                 usb_serial_deregister(&opticon_device);
 490         return retval;
 491 }
 492
 493 static void __exit opticon_exit(void)
 494 {
 495         usb_deregister(&opticon_driver);
 496         usb_serial_deregister(&opticon_device);
 497 }
 498
 499 module_init(opticon_init);
 500 module_exit(opticon_exit);
 501 MODULE_LICENSE("GPL");
 502
 503 module_param(debug, bool, S_IRUGO | S_IWUSR);
 504 MODULE_PARM_DESC(debug, "Debug enabled or not");