drivers/usb/misc/legousbtower.c

   1 /*
   2  * LEGO USB Tower driver
   3  *
   4  * Copyright (C) 2003 David Glance <davidgsf@sourceforge.net>
   5  *               2001-2004 Juergen Stuber <starblue@users.sourceforge.net>
   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 as
   9  *      published by the Free Software Foundation; either version 2 of
  10  *      the License, or (at your option) any later version.
  11  *
  12  * derived from USB Skeleton driver - 0.5
  13  * Copyright (C) 2001 Greg Kroah-Hartman (greg@kroah.com)
  14  *
  15  * History:
  16  *
  17  * 2001-10-13 - 0.1 js
  18  *   - first version
  19  * 2001-11-03 - 0.2 js
  20  *   - simplified buffering, one-shot URBs for writing
  21  * 2001-11-10 - 0.3 js
  22  *   - removed IOCTL (setting power/mode is more complicated, postponed)
  23  * 2001-11-28 - 0.4 js
  24  *   - added vendor commands for mode of operation and power level in open
  25  * 2001-12-04 - 0.5 js
  26  *   - set IR mode by default (by oversight 0.4 set VLL mode)
  27  * 2002-01-11 - 0.5? pcchan
  28  *   - make read buffer reusable and work around bytes_to_write issue between
  29  *     uhci and legusbtower
  30  * 2002-09-23 - 0.52 david (david@csse.uwa.edu.au)
  31  *   - imported into lejos project
  32  *   - changed wake_up to wake_up_interruptible
  33  *   - changed to use lego0 rather than tower0
  34  *   - changed dbg() to use __func__ rather than deprecated __func__
  35  * 2003-01-12 - 0.53 david (david@csse.uwa.edu.au)
  36  *   - changed read and write to write everything or
  37  *     timeout (from a patch by Chris Riesen and Brett Thaeler driver)
  38  *   - added ioctl functionality to set timeouts
  39  * 2003-07-18 - 0.54 davidgsf (david@csse.uwa.edu.au)
  40  *   - initial import into LegoUSB project
  41  *   - merge of existing LegoUSB.c driver
  42  * 2003-07-18 - 0.56 davidgsf (david@csse.uwa.edu.au)
  43  *   - port to 2.6 style driver
  44  * 2004-02-29 - 0.6 Juergen Stuber <starblue@users.sourceforge.net>
  45  *   - fix locking
  46  *   - unlink read URBs which are no longer needed
  47  *   - allow increased buffer size, eliminates need for timeout on write
  48  *   - have read URB running continuously
  49  *   - added poll
  50  *   - forbid seeking
  51  *   - added nonblocking I/O
  52  *   - changed back __func__ to __func__
  53  *   - read and log tower firmware version
  54  *   - reset tower on probe, avoids failure of first write
  55  * 2004-03-09 - 0.7 Juergen Stuber <starblue@users.sourceforge.net>
  56  *   - timeout read now only after inactivity, shorten default accordingly
  57  * 2004-03-11 - 0.8 Juergen Stuber <starblue@users.sourceforge.net>
  58  *   - log major, minor instead of possibly confusing device filename
  59  *   - whitespace cleanup
  60  * 2004-03-12 - 0.9 Juergen Stuber <starblue@users.sourceforge.net>
  61  *   - normalize whitespace in debug messages
  62  *   - take care about endianness in control message responses
  63  * 2004-03-13 - 0.91 Juergen Stuber <starblue@users.sourceforge.net>
  64  *   - make default intervals longer to accommodate current EHCI driver
  65  * 2004-03-19 - 0.92 Juergen Stuber <starblue@users.sourceforge.net>
  66  *   - replaced atomic_t by memory barriers
  67  * 2004-04-21 - 0.93 Juergen Stuber <starblue@users.sourceforge.net>
  68  *   - wait for completion of write urb in release (needed for remotecontrol)
  69  *   - corrected poll for write direction (missing negation)
  70  * 2004-04-22 - 0.94 Juergen Stuber <starblue@users.sourceforge.net>
  71  *   - make device locking interruptible
  72  * 2004-04-30 - 0.95 Juergen Stuber <starblue@users.sourceforge.net>
  73  *   - check for valid udev on resubmitting and unlinking urbs
  74  * 2004-08-03 - 0.96 Juergen Stuber <starblue@users.sourceforge.net>
  75  *   - move reset into open to clean out spurious data
  76  */
  77
  78 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
  79
  80 #include <linux/kernel.h>
  81 #include <linux/errno.h>
  82 #include <linux/slab.h>
  83 #include <linux/module.h>
  84 #include <linux/completion.h>
  85 #include <linux/mutex.h>
  86 #include <asm/uaccess.h>
  87 #include <linux/usb.h>
  88 #include <linux/poll.h>
  89
  90
  91 /* Version Information */
  92 #define DRIVER_VERSION "v0.96"
  93 #define DRIVER_AUTHOR "Juergen Stuber <starblue@sourceforge.net>"
  94 #define DRIVER_DESC "LEGO USB Tower Driver"
  95
  96
  97 /* The defaults are chosen to work with the latest versions of leJOS and NQC.
  98  */
  99
 100 /* Some legacy software likes to receive packets in one piece.
 101  * In this case read_buffer_size should exceed the maximal packet length
 102  * (417 for datalog uploads), and packet_timeout should be set.
 103  */
 104 static int read_buffer_size = 480;
 105 module_param(read_buffer_size, int, 0);
 106 MODULE_PARM_DESC(read_buffer_size, "Read buffer size");
 107
 108 /* Some legacy software likes to send packets in one piece.
 109  * In this case write_buffer_size should exceed the maximal packet length
 110  * (417 for firmware and program downloads).
 111  * A problem with long writes is that the following read may time out
 112  * if the software is not prepared to wait long enough.
 113  */
 114 static int write_buffer_size = 480;
 115 module_param(write_buffer_size, int, 0);
 116 MODULE_PARM_DESC(write_buffer_size, "Write buffer size");
 117
 118 /* Some legacy software expects reads to contain whole LASM packets.
 119  * To achieve this, characters which arrive before a packet timeout
 120  * occurs will be returned in a single read operation.
 121  * A problem with long reads is that the software may time out
 122  * if it is not prepared to wait long enough.
 123  * The packet timeout should be greater than the time between the
 124  * reception of subsequent characters, which should arrive about
 125  * every 5ms for the standard 2400 baud.
 126  * Set it to 0 to disable.
 127  */
 128 static int packet_timeout = 50;
 129 module_param(packet_timeout, int, 0);
 130 MODULE_PARM_DESC(packet_timeout, "Packet timeout in ms");
 131
 132 /* Some legacy software expects blocking reads to time out.
 133  * Timeout occurs after the specified time of read and write inactivity.
 134  * Set it to 0 to disable.
 135  */
 136 static int read_timeout = 200;
 137 module_param(read_timeout, int, 0);
 138 MODULE_PARM_DESC(read_timeout, "Read timeout in ms");
 139
 140 /* As of kernel version 2.6.4 ehci-hcd uses an
 141  * "only one interrupt transfer per frame" shortcut
 142  * to simplify the scheduling of periodic transfers.
 143  * This conflicts with our standard 1ms intervals for in and out URBs.
 144  * We use default intervals of 2ms for in and 8ms for out transfers,
 145  * which is fast enough for 2400 baud and allows a small additional load.
 146  * Increase the interval to allow more devices that do interrupt transfers,
 147  * or set to 0 to use the standard interval from the endpoint descriptors.
 148  */
 149 static int interrupt_in_interval = 2;
 150 module_param(interrupt_in_interval, int, 0);
 151 MODULE_PARM_DESC(interrupt_in_interval, "Interrupt in interval in ms");
 152
 153 static int interrupt_out_interval = 8;
 154 module_param(interrupt_out_interval, int, 0);
 155 MODULE_PARM_DESC(interrupt_out_interval, "Interrupt out interval in ms");
 156
 157 /* Define these values to match your device */
 158 #define LEGO_USB_TOWER_VENDOR_ID        0x0694
 159 #define LEGO_USB_TOWER_PRODUCT_ID       0x0001
 160
 161 /* Vendor requests */
 162 #define LEGO_USB_TOWER_REQUEST_RESET            0x04
 163 #define LEGO_USB_TOWER_REQUEST_GET_VERSION      0xFD
 164
 165 struct tower_reset_reply {
 166         __le16 size;            /* little-endian */
 167         __u8 err_code;
 168         __u8 spare;
 169 } __attribute__ ((packed));
 170
 171 struct tower_get_version_reply {
 172         __le16 size;            /* little-endian */
 173         __u8 err_code;
 174         __u8 spare;
 175         __u8 major;
 176         __u8 minor;
 177         __le16 build_no;                /* little-endian */
 178 } __attribute__ ((packed));
 179
 180
 181 /* table of devices that work with this driver */
 182 static const struct usb_device_id tower_table[] = {
 183         { USB_DEVICE(LEGO_USB_TOWER_VENDOR_ID, LEGO_USB_TOWER_PRODUCT_ID) },
 184         { }                                     /* Terminating entry */
 185 };
 186
 187 MODULE_DEVICE_TABLE (usb, tower_table);
 188
 189 #define LEGO_USB_TOWER_MINOR_BASE       160
 190
 191
 192 /* Structure to hold all of our device specific stuff */
 193 struct lego_usb_tower {
 194         struct mutex            lock;           /* locks this structure */
 195         struct usb_device*      udev;           /* save off the usb device pointer */
 196         unsigned char           minor;          /* the starting minor number for this device */
 197
 198         int                     open_count;     /* number of times this port has been opened */
 199         unsigned long           disconnected:1;
 200
 201         char*                   read_buffer;
 202         size_t                  read_buffer_length; /* this much came in */
 203         size_t                  read_packet_length; /* this much will be returned on read */
 204         spinlock_t              read_buffer_lock;
 205         int                     packet_timeout_jiffies;
 206         unsigned long           read_last_arrival;
 207
 208         wait_queue_head_t       read_wait;
 209         wait_queue_head_t       write_wait;
 210
 211         char*                   interrupt_in_buffer;
 212         struct usb_endpoint_descriptor* interrupt_in_endpoint;
 213         struct urb*             interrupt_in_urb;
 214         int                     interrupt_in_interval;
 215         int                     interrupt_in_running;
 216         int                     interrupt_in_done;
 217
 218         char*                   interrupt_out_buffer;
 219         struct usb_endpoint_descriptor* interrupt_out_endpoint;
 220         struct urb*             interrupt_out_urb;
 221         int                     interrupt_out_interval;
 222         int                     interrupt_out_busy;
 223
 224 };
 225
 226
 227 /* local function prototypes */
 228 static ssize_t tower_read       (struct file *file, char __user *buffer, size_t count, loff_t *ppos);
 229 static ssize_t tower_write      (struct file *file, const char __user *buffer, size_t count, loff_t *ppos);
 230 static inline void tower_delete (struct lego_usb_tower *dev);
 231 static int tower_open           (struct inode *inode, struct file *file);
 232 static int tower_release        (struct inode *inode, struct file *file);
 233 static unsigned int tower_poll  (struct file *file, poll_table *wait);
 234 static loff_t tower_llseek      (struct file *file, loff_t off, int whence);
 235
 236 static void tower_abort_transfers (struct lego_usb_tower *dev);
 237 static void tower_check_for_read_packet (struct lego_usb_tower *dev);
 238 static void tower_interrupt_in_callback (struct urb *urb);
 239 static void tower_interrupt_out_callback (struct urb *urb);
 240
 241 static int  tower_probe (struct usb_interface *interface, const struct usb_device_id *id);
 242 static void tower_disconnect    (struct usb_interface *interface);
 243
 244
 245 /* file operations needed when we register this driver */
 246 static const struct file_operations tower_fops = {
 247         .owner =        THIS_MODULE,
 248         .read  =        tower_read,
 249         .write =        tower_write,
 250         .open =         tower_open,
 251         .release =      tower_release,
 252         .poll =         tower_poll,
 253         .llseek =       tower_llseek,
 254 };
 255
 256 static char *legousbtower_devnode(struct device *dev, umode_t *mode)
 257 {
 258         return kasprintf(GFP_KERNEL, "usb/%s", dev_name(dev));
 259 }
 260
 261 /*
 262  * usb class driver info in order to get a minor number from the usb core,
 263  * and to have the device registered with the driver core
 264  */
 265 static struct usb_class_driver tower_class = {
 266         .name =         "legousbtower%d",
 267         .devnode =      legousbtower_devnode,
 268         .fops =         &tower_fops,
 269         .minor_base =   LEGO_USB_TOWER_MINOR_BASE,
 270 };
 271
 272
 273 /* usb specific object needed to register this driver with the usb subsystem */
 274 static struct usb_driver tower_driver = {
 275         .name =         "legousbtower",
 276         .probe =        tower_probe,
 277         .disconnect =   tower_disconnect,
 278         .id_table =     tower_table,
 279 };
 280
 281
 282 /**
 283  *      lego_usb_tower_debug_data
 284  */
 285 static inline void lego_usb_tower_debug_data(struct device *dev,
 286                                              const char *function, int size,
 287                                              const unsigned char *data)
 288 {
 289         dev_dbg(dev, "%s - length = %d, data = %*ph\n",
 290                 function, size, size, data);
 291 }
 292
 293
 294 /**
 295  *      tower_delete
 296  */
 297 static inline void tower_delete (struct lego_usb_tower *dev)
 298 {
 299         /* free data structures */
 300         usb_free_urb(dev->interrupt_in_urb);
 301         usb_free_urb(dev->interrupt_out_urb);
 302         kfree (dev->read_buffer);
 303         kfree (dev->interrupt_in_buffer);
 304         kfree (dev->interrupt_out_buffer);
 305         kfree (dev);
 306 }
 307
 308
 309 /**
 310  *      tower_open
 311  */
 312 static int tower_open (struct inode *inode, struct file *file)
 313 {
 314         struct lego_usb_tower *dev = NULL;
 315         int subminor;
 316         int retval = 0;
 317         struct usb_interface *interface;
 318         struct tower_reset_reply *reset_reply;
 319         int result;
 320
 321         reset_reply = kmalloc(sizeof(*reset_reply), GFP_KERNEL);
 322
 323         if (!reset_reply) {
 324                 retval = -ENOMEM;
 325                 goto exit;
 326         }
 327
 328         nonseekable_open(inode, file);
 329         subminor = iminor(inode);
 330
 331         interface = usb_find_interface (&tower_driver, subminor);
 332
 333         if (!interface) {
 334                 pr_err("error, can't find device for minor %d\n", subminor);
 335                 retval = -ENODEV;
 336                 goto exit;
 337         }
 338
 339         dev = usb_get_intfdata(interface);
 340         if (!dev) {
 341                 retval = -ENODEV;
 342                 goto exit;
 343         }
 344
 345         /* lock this device */
 346         if (mutex_lock_interruptible(&dev->lock)) {
 347                 retval = -ERESTARTSYS;
 348                 goto exit;
 349         }
 350
 351
 352         /* allow opening only once */
 353         if (dev->open_count) {
 354                 retval = -EBUSY;
 355                 goto unlock_exit;
 356         }
 357
 358         /* reset the tower */
 359         result = usb_control_msg (dev->udev,
 360                                   usb_rcvctrlpipe(dev->udev, 0),
 361                                   LEGO_USB_TOWER_REQUEST_RESET,
 362                                   USB_TYPE_VENDOR | USB_DIR_IN | USB_RECIP_DEVICE,
 363                                   0,
 364                                   0,
 365                                   reset_reply,
 366                                   sizeof(*reset_reply),
 367                                   1000);
 368         if (result < 0) {
 369                 dev_err(&dev->udev->dev,
 370                         "LEGO USB Tower reset control request failed\n");
 371                 retval = result;
 372                 goto unlock_exit;
 373         }
 374
 375         /* initialize in direction */
 376         dev->read_buffer_length = 0;
 377         dev->read_packet_length = 0;
 378         usb_fill_int_urb (dev->interrupt_in_urb,
 379                           dev->udev,
 380                           usb_rcvintpipe(dev->udev, dev->interrupt_in_endpoint->bEndpointAddress),
 381                           dev->interrupt_in_buffer,
 382                           usb_endpoint_maxp(dev->interrupt_in_endpoint),
 383                           tower_interrupt_in_callback,
 384                           dev,
 385                           dev->interrupt_in_interval);
 386
 387         dev->interrupt_in_running = 1;
 388         dev->interrupt_in_done = 0;
 389         mb();
 390
 391         retval = usb_submit_urb (dev->interrupt_in_urb, GFP_KERNEL);
 392         if (retval) {
 393                 dev_err(&dev->udev->dev,
 394                         "Couldn't submit interrupt_in_urb %d\n", retval);
 395                 dev->interrupt_in_running = 0;
 396                 goto unlock_exit;
 397         }
 398
 399         /* save device in the file's private structure */
 400         file->private_data = dev;
 401
 402         dev->open_count = 1;
 403
 404 unlock_exit:
 405         mutex_unlock(&dev->lock);
 406
 407 exit:
 408         kfree(reset_reply);
 409         return retval;
 410 }
 411
 412 /**
 413  *      tower_release
 414  */
 415 static int tower_release (struct inode *inode, struct file *file)
 416 {
 417         struct lego_usb_tower *dev;
 418         int retval = 0;
 419
 420         dev = file->private_data;
 421
 422         if (dev == NULL) {
 423                 retval = -ENODEV;
 424                 goto exit;
 425         }
 426
 427         if (mutex_lock_interruptible(&dev->lock)) {
 428                 retval = -ERESTARTSYS;
 429                 goto exit;
 430         }
 431
 432         if (dev->open_count != 1) {
 433                 dev_dbg(&dev->udev->dev, "%s: device not opened exactly once\n",
 434                         __func__);
 435                 retval = -ENODEV;
 436                 goto unlock_exit;
 437         }
 438
 439         if (dev->disconnected) {
 440                 /* the device was unplugged before the file was released */
 441
 442                 /* unlock here as tower_delete frees dev */
 443                 mutex_unlock(&dev->lock);
 444                 tower_delete (dev);
 445                 goto exit;
 446         }
 447
 448         /* wait until write transfer is finished */
 449         if (dev->interrupt_out_busy) {
 450                 wait_event_interruptible_timeout (dev->write_wait, !dev->interrupt_out_busy, 2 * HZ);
 451         }
 452         tower_abort_transfers (dev);
 453         dev->open_count = 0;
 454
 455 unlock_exit:
 456         mutex_unlock(&dev->lock);
 457 exit:
 458         return retval;
 459 }
 460
 461
 462 /**
 463  *      tower_abort_transfers
 464  *      aborts transfers and frees associated data structures
 465  */
 466 static void tower_abort_transfers (struct lego_usb_tower *dev)
 467 {
 468         if (dev == NULL)
 469                 return;
 470
 471         /* shutdown transfer */
 472         if (dev->interrupt_in_running) {
 473                 dev->interrupt_in_running = 0;
 474                 mb();
 475                 usb_kill_urb(dev->interrupt_in_urb);
 476         }
 477         if (dev->interrupt_out_busy)
 478                 usb_kill_urb(dev->interrupt_out_urb);
 479 }
 480
 481
 482 /**
 483  *      tower_check_for_read_packet
 484  *
 485  *      To get correct semantics for signals and non-blocking I/O
 486  *      with packetizing we pretend not to see any data in the read buffer
 487  *      until it has been there unchanged for at least
 488  *      dev->packet_timeout_jiffies, or until the buffer is full.
 489  */
 490 static void tower_check_for_read_packet (struct lego_usb_tower *dev)
 491 {
 492         spin_lock_irq (&dev->read_buffer_lock);
 493         if (!packet_timeout
 494             || time_after(jiffies, dev->read_last_arrival + dev->packet_timeout_jiffies)
 495             || dev->read_buffer_length == read_buffer_size) {
 496                 dev->read_packet_length = dev->read_buffer_length;
 497         }
 498         dev->interrupt_in_done = 0;
 499         spin_unlock_irq (&dev->read_buffer_lock);
 500 }
 501
 502
 503 /**
 504  *      tower_poll
 505  */
 506 static unsigned int tower_poll (struct file *file, poll_table *wait)
 507 {
 508         struct lego_usb_tower *dev;
 509         unsigned int mask = 0;
 510
 511         dev = file->private_data;
 512
 513         if (dev->disconnected)
 514                 return POLLERR | POLLHUP;
 515
 516         poll_wait(file, &dev->read_wait, wait);
 517         poll_wait(file, &dev->write_wait, wait);
 518
 519         tower_check_for_read_packet(dev);
 520         if (dev->read_packet_length > 0) {
 521                 mask |= POLLIN | POLLRDNORM;
 522         }
 523         if (!dev->interrupt_out_busy) {
 524                 mask |= POLLOUT | POLLWRNORM;
 525         }
 526
 527         return mask;
 528 }
 529
 530
 531 /**
 532  *      tower_llseek
 533  */
 534 static loff_t tower_llseek (struct file *file, loff_t off, int whence)
 535 {
 536         return -ESPIPE;         /* unseekable */
 537 }
 538
 539
 540 /**
 541  *      tower_read
 542  */
 543 static ssize_t tower_read (struct file *file, char __user *buffer, size_t count, loff_t *ppos)
 544 {
 545         struct lego_usb_tower *dev;
 546         size_t bytes_to_read;
 547         int i;
 548         int retval = 0;
 549         unsigned long timeout = 0;
 550
 551         dev = file->private_data;
 552
 553         /* lock this object */
 554         if (mutex_lock_interruptible(&dev->lock)) {
 555                 retval = -ERESTARTSYS;
 556                 goto exit;
 557         }
 558
 559         /* verify that the device wasn't unplugged */
 560         if (dev->disconnected) {
 561                 retval = -ENODEV;
 562                 pr_err("No device or device unplugged %d\n", retval);
 563                 goto unlock_exit;
 564         }
 565
 566         /* verify that we actually have some data to read */
 567         if (count == 0) {
 568                 dev_dbg(&dev->udev->dev, "read request of 0 bytes\n");
 569                 goto unlock_exit;
 570         }
 571
 572         if (read_timeout) {
 573                 timeout = jiffies + msecs_to_jiffies(read_timeout);
 574         }
 575
 576         /* wait for data */
 577         tower_check_for_read_packet (dev);
 578         while (dev->read_packet_length == 0) {
 579                 if (file->f_flags & O_NONBLOCK) {
 580                         retval = -EAGAIN;
 581                         goto unlock_exit;
 582                 }
 583                 retval = wait_event_interruptible_timeout(dev->read_wait, dev->interrupt_in_done, dev->packet_timeout_jiffies);
 584                 if (retval < 0) {
 585                         goto unlock_exit;
 586                 }
 587
 588                 /* reset read timeout during read or write activity */
 589                 if (read_timeout
 590                     && (dev->read_buffer_length || dev->interrupt_out_busy)) {
 591                         timeout = jiffies + msecs_to_jiffies(read_timeout);
 592                 }
 593                 /* check for read timeout */
 594                 if (read_timeout && time_after (jiffies, timeout)) {
 595                         retval = -ETIMEDOUT;
 596                         goto unlock_exit;
 597                 }
 598                 tower_check_for_read_packet (dev);
 599         }
 600
 601         /* copy the data from read_buffer into userspace */
 602         bytes_to_read = min(count, dev->read_packet_length);
 603
 604         if (copy_to_user (buffer, dev->read_buffer, bytes_to_read)) {
 605                 retval = -EFAULT;
 606                 goto unlock_exit;
 607         }
 608
 609         spin_lock_irq (&dev->read_buffer_lock);
 610         dev->read_buffer_length -= bytes_to_read;
 611         dev->read_packet_length -= bytes_to_read;
 612         for (i=0; i<dev->read_buffer_length; i++) {
 613                 dev->read_buffer[i] = dev->read_buffer[i+bytes_to_read];
 614         }
 615         spin_unlock_irq (&dev->read_buffer_lock);
 616
 617         retval = bytes_to_read;
 618
 619 unlock_exit:
 620         /* unlock the device */
 621         mutex_unlock(&dev->lock);
 622
 623 exit:
 624         return retval;
 625 }
 626
 627
 628 /**
 629  *      tower_write
 630  */
 631 static ssize_t tower_write (struct file *file, const char __user *buffer, size_t count, loff_t *ppos)
 632 {
 633         struct lego_usb_tower *dev;
 634         size_t bytes_to_write;
 635         int retval = 0;
 636
 637         dev = file->private_data;
 638
 639         /* lock this object */
 640         if (mutex_lock_interruptible(&dev->lock)) {
 641                 retval = -ERESTARTSYS;
 642                 goto exit;
 643         }
 644
 645         /* verify that the device wasn't unplugged */
 646         if (dev->disconnected) {
 647                 retval = -ENODEV;
 648                 pr_err("No device or device unplugged %d\n", retval);
 649                 goto unlock_exit;
 650         }
 651
 652         /* verify that we actually have some data to write */
 653         if (count == 0) {
 654                 dev_dbg(&dev->udev->dev, "write request of 0 bytes\n");
 655                 goto unlock_exit;
 656         }
 657
 658         /* wait until previous transfer is finished */
 659         while (dev->interrupt_out_busy) {
 660                 if (file->f_flags & O_NONBLOCK) {
 661                         retval = -EAGAIN;
 662                         goto unlock_exit;
 663                 }
 664                 retval = wait_event_interruptible (dev->write_wait, !dev->interrupt_out_busy);
 665                 if (retval) {
 666                         goto unlock_exit;
 667                 }
 668         }
 669
 670         /* write the data into interrupt_out_buffer from userspace */
 671         bytes_to_write = min_t(int, count, write_buffer_size);
 672         dev_dbg(&dev->udev->dev, "%s: count = %Zd, bytes_to_write = %Zd\n",
 673                 __func__, count, bytes_to_write);
 674
 675         if (copy_from_user (dev->interrupt_out_buffer, buffer, bytes_to_write)) {
 676                 retval = -EFAULT;
 677                 goto unlock_exit;
 678         }
 679
 680         /* send off the urb */
 681         usb_fill_int_urb(dev->interrupt_out_urb,
 682                          dev->udev,
 683                          usb_sndintpipe(dev->udev, dev->interrupt_out_endpoint->bEndpointAddress),
 684                          dev->interrupt_out_buffer,
 685                          bytes_to_write,
 686                          tower_interrupt_out_callback,
 687                          dev,
 688                          dev->interrupt_out_interval);
 689
 690         dev->interrupt_out_busy = 1;
 691         wmb();
 692
 693         retval = usb_submit_urb (dev->interrupt_out_urb, GFP_KERNEL);
 694         if (retval) {
 695                 dev->interrupt_out_busy = 0;
 696                 dev_err(&dev->udev->dev,
 697                         "Couldn't submit interrupt_out_urb %d\n", retval);
 698                 goto unlock_exit;
 699         }
 700         retval = bytes_to_write;
 701
 702 unlock_exit:
 703         /* unlock the device */
 704         mutex_unlock(&dev->lock);
 705
 706 exit:
 707         return retval;
 708 }
 709
 710
 711 /**
 712  *      tower_interrupt_in_callback
 713  */
 714 static void tower_interrupt_in_callback (struct urb *urb)
 715 {
 716         struct lego_usb_tower *dev = urb->context;
 717         int status = urb->status;
 718         int retval;
 719
 720         lego_usb_tower_debug_data(&dev->udev->dev, __func__,
 721                                   urb->actual_length, urb->transfer_buffer);
 722
 723         if (status) {
 724                 if (status == -ENOENT ||
 725                     status == -ECONNRESET ||
 726                     status == -ESHUTDOWN) {
 727                         goto exit;
 728                 } else {
 729                         dev_dbg(&dev->udev->dev,
 730                                 "%s: nonzero status received: %d\n", __func__,
 731                                 status);
 732                         goto resubmit; /* maybe we can recover */
 733                 }
 734         }
 735
 736         if (urb->actual_length > 0) {
 737                 spin_lock (&dev->read_buffer_lock);
 738                 if (dev->read_buffer_length + urb->actual_length < read_buffer_size) {
 739                         memcpy (dev->read_buffer + dev->read_buffer_length,
 740                                 dev->interrupt_in_buffer,
 741                                 urb->actual_length);
 742                         dev->read_buffer_length += urb->actual_length;
 743                         dev->read_last_arrival = jiffies;
 744                         dev_dbg(&dev->udev->dev, "%s: received %d bytes\n",
 745                                 __func__, urb->actual_length);
 746                 } else {
 747                         pr_warn("read_buffer overflow, %d bytes dropped\n",
 748                                 urb->actual_length);
 749                 }
 750                 spin_unlock (&dev->read_buffer_lock);
 751         }
 752
 753 resubmit:
 754         /* resubmit if we're still running */
 755         if (dev->interrupt_in_running) {
 756                 retval = usb_submit_urb (dev->interrupt_in_urb, GFP_ATOMIC);
 757                 if (retval)
 758                         dev_err(&dev->udev->dev,
 759                                 "%s: usb_submit_urb failed (%d)\n",
 760                                 __func__, retval);
 761         }
 762
 763 exit:
 764         dev->interrupt_in_done = 1;
 765         wake_up_interruptible (&dev->read_wait);
 766 }
 767
 768
 769 /**
 770  *      tower_interrupt_out_callback
 771  */
 772 static void tower_interrupt_out_callback (struct urb *urb)
 773 {
 774         struct lego_usb_tower *dev = urb->context;
 775         int status = urb->status;
 776
 777         lego_usb_tower_debug_data(&dev->udev->dev, __func__,
 778                                   urb->actual_length, urb->transfer_buffer);
 779
 780         /* sync/async unlink faults aren't errors */
 781         if (status && !(status == -ENOENT ||
 782                         status == -ECONNRESET ||
 783                         status == -ESHUTDOWN)) {
 784                 dev_dbg(&dev->udev->dev,
 785                         "%s: nonzero write bulk status received: %d\n", __func__,
 786                         status);
 787         }
 788
 789         dev->interrupt_out_busy = 0;
 790         wake_up_interruptible(&dev->write_wait);
 791 }
 792
 793
 794 /**
 795  *      tower_probe
 796  *
 797  *      Called by the usb core when a new device is connected that it thinks
 798  *      this driver might be interested in.
 799  */
 800 static int tower_probe (struct usb_interface *interface, const struct usb_device_id *id)
 801 {
 802         struct device *idev = &interface->dev;
 803         struct usb_device *udev = interface_to_usbdev(interface);
 804         struct lego_usb_tower *dev = NULL;
 805         struct usb_host_interface *iface_desc;
 806         struct usb_endpoint_descriptor* endpoint;
 807         struct tower_get_version_reply *get_version_reply = NULL;
 808         int i;
 809         int retval = -ENOMEM;
 810         int result;
 811
 812         /* allocate memory for our device state and initialize it */
 813
 814         dev = kmalloc (sizeof(struct lego_usb_tower), GFP_KERNEL);
 815
 816         if (dev == NULL) {
 817                 dev_err(idev, "Out of memory\n");
 818                 goto exit;
 819         }
 820
 821         mutex_init(&dev->lock);
 822
 823         dev->udev = udev;
 824         dev->open_count = 0;
 825         dev->disconnected = 0;
 826
 827         dev->read_buffer = NULL;
 828         dev->read_buffer_length = 0;
 829         dev->read_packet_length = 0;
 830         spin_lock_init (&dev->read_buffer_lock);
 831         dev->packet_timeout_jiffies = msecs_to_jiffies(packet_timeout);
 832         dev->read_last_arrival = jiffies;
 833
 834         init_waitqueue_head (&dev->read_wait);
 835         init_waitqueue_head (&dev->write_wait);
 836
 837         dev->interrupt_in_buffer = NULL;
 838         dev->interrupt_in_endpoint = NULL;
 839         dev->interrupt_in_urb = NULL;
 840         dev->interrupt_in_running = 0;
 841         dev->interrupt_in_done = 0;
 842
 843         dev->interrupt_out_buffer = NULL;
 844         dev->interrupt_out_endpoint = NULL;
 845         dev->interrupt_out_urb = NULL;
 846         dev->interrupt_out_busy = 0;
 847
 848         iface_desc = interface->cur_altsetting;
 849
 850         /* set up the endpoint information */
 851         for (i = 0; i < iface_desc->desc.bNumEndpoints; ++i) {
 852                 endpoint = &iface_desc->endpoint[i].desc;
 853
 854                 if (usb_endpoint_xfer_int(endpoint)) {
 855                         if (usb_endpoint_dir_in(endpoint))
 856                                 dev->interrupt_in_endpoint = endpoint;
 857                         else
 858                                 dev->interrupt_out_endpoint = endpoint;
 859                 }
 860         }
 861         if(dev->interrupt_in_endpoint == NULL) {
 862                 dev_err(idev, "interrupt in endpoint not found\n");
 863                 goto error;
 864         }
 865         if (dev->interrupt_out_endpoint == NULL) {
 866                 dev_err(idev, "interrupt out endpoint not found\n");
 867                 goto error;
 868         }
 869
 870         dev->read_buffer = kmalloc (read_buffer_size, GFP_KERNEL);
 871         if (!dev->read_buffer) {
 872                 dev_err(idev, "Couldn't allocate read_buffer\n");
 873                 goto error;
 874         }
 875         dev->interrupt_in_buffer = kmalloc (usb_endpoint_maxp(dev->interrupt_in_endpoint), GFP_KERNEL);
 876         if (!dev->interrupt_in_buffer) {
 877                 dev_err(idev, "Couldn't allocate interrupt_in_buffer\n");
 878                 goto error;
 879         }
 880         dev->interrupt_in_urb = usb_alloc_urb(0, GFP_KERNEL);
 881         if (!dev->interrupt_in_urb) {
 882                 dev_err(idev, "Couldn't allocate interrupt_in_urb\n");
 883                 goto error;
 884         }
 885         dev->interrupt_out_buffer = kmalloc (write_buffer_size, GFP_KERNEL);
 886         if (!dev->interrupt_out_buffer) {
 887                 dev_err(idev, "Couldn't allocate interrupt_out_buffer\n");
 888                 goto error;
 889         }
 890         dev->interrupt_out_urb = usb_alloc_urb(0, GFP_KERNEL);
 891         if (!dev->interrupt_out_urb) {
 892                 dev_err(idev, "Couldn't allocate interrupt_out_urb\n");
 893                 goto error;
 894         }
 895         dev->interrupt_in_interval = interrupt_in_interval ? interrupt_in_interval : dev->interrupt_in_endpoint->bInterval;
 896         dev->interrupt_out_interval = interrupt_out_interval ? interrupt_out_interval : dev->interrupt_out_endpoint->bInterval;
 897
 898         get_version_reply = kmalloc(sizeof(*get_version_reply), GFP_KERNEL);
 899
 900         if (!get_version_reply) {
 901                 retval = -ENOMEM;
 902                 goto error;
 903         }
 904
 905         /* get the firmware version and log it */
 906         result = usb_control_msg (udev,
 907                                   usb_rcvctrlpipe(udev, 0),
 908                                   LEGO_USB_TOWER_REQUEST_GET_VERSION,
 909                                   USB_TYPE_VENDOR | USB_DIR_IN | USB_RECIP_DEVICE,
 910                                   0,
 911                                   0,
 912                                   get_version_reply,
 913                                   sizeof(*get_version_reply),
 914                                   1000);
 915         if (result < sizeof(*get_version_reply)) {
 916                 if (result >= 0)
 917                         result = -EIO;
 918                 dev_err(idev, "get version request failed: %d\n", result);
 919                 retval = result;
 920                 goto error;
 921         }
 922         dev_info(&interface->dev,
 923                  "LEGO USB Tower firmware version is %d.%d build %d\n",
 924                  get_version_reply->major,
 925                  get_version_reply->minor,
 926                  le16_to_cpu(get_version_reply->build_no));
 927
 928         /* we can register the device now, as it is ready */
 929         usb_set_intfdata (interface, dev);
 930
 931         retval = usb_register_dev (interface, &tower_class);
 932
 933         if (retval) {
 934                 /* something prevented us from registering this driver */
 935                 dev_err(idev, "Not able to get a minor for this device.\n");
 936                 goto error;
 937         }
 938         dev->minor = interface->minor;
 939
 940         /* let the user know what node this device is now attached to */
 941         dev_info(&interface->dev, "LEGO USB Tower #%d now attached to major "
 942                  "%d minor %d\n", (dev->minor - LEGO_USB_TOWER_MINOR_BASE),
 943                  USB_MAJOR, dev->minor);
 944
 945 exit:
 946         kfree(get_version_reply);
 947         return retval;
 948
 949 error:
 950         kfree(get_version_reply);
 951         tower_delete(dev);
 952         return retval;
 953 }
 954
 955
 956 /**
 957  *      tower_disconnect
 958  *
 959  *      Called by the usb core when the device is removed from the system.
 960  */
 961 static void tower_disconnect (struct usb_interface *interface)
 962 {
 963         struct lego_usb_tower *dev;
 964         int minor;
 965
 966         dev = usb_get_intfdata (interface);
 967
 968         minor = dev->minor;
 969
 970         /* give back our minor and prevent further open() */
 971         usb_deregister_dev (interface, &tower_class);
 972
 973         /* stop I/O */
 974         usb_poison_urb(dev->interrupt_in_urb);
 975         usb_poison_urb(dev->interrupt_out_urb);
 976
 977         mutex_lock(&dev->lock);
 978
 979         /* if the device is not opened, then we clean up right now */
 980         if (!dev->open_count) {
 981                 mutex_unlock(&dev->lock);
 982                 tower_delete (dev);
 983         } else {
 984                 dev->disconnected = 1;
 985                 /* wake up pollers */
 986                 wake_up_interruptible_all(&dev->read_wait);
 987                 wake_up_interruptible_all(&dev->write_wait);
 988                 mutex_unlock(&dev->lock);
 989         }
 990
 991         dev_info(&interface->dev, "LEGO USB Tower #%d now disconnected\n",
 992                  (minor - LEGO_USB_TOWER_MINOR_BASE));
 993 }
 994
 995 module_usb_driver(tower_driver);
 996
 997 MODULE_AUTHOR(DRIVER_AUTHOR);
 998 MODULE_DESCRIPTION(DRIVER_DESC);
 999 #ifdef MODULE_LICENSE
1000 MODULE_LICENSE("GPL");
1001 #endif