git.oblomov.eu Git - linux-2.6/blob - 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 __FUNCTION__
  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 __FUNCTION__
  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 #include <linux/kernel.h>
  79 #include <linux/errno.h>
  80 #include <linux/init.h>
  81 #include <linux/slab.h>
  82 #include <linux/module.h>
  83 #include <linux/completion.h>
  84 #include <linux/mutex.h>
  85 #include <asm/uaccess.h>
  86 #include <linux/usb.h>
  87 #include <linux/poll.h>
  88
  89
  90 #ifdef CONFIG_USB_DEBUG
  91         static int debug = 4;
  92 #else
  93         static int debug = 0;
  94 #endif
  95
  96 /* Use our own dbg macro */
  97 #undef dbg
  98 #define dbg(lvl, format, arg...) do { if (debug >= lvl) printk(KERN_DEBUG  __FILE__ ": " format "\n", ## arg); } while (0)
  99
 100
 101 /* Version Information */
 102 #define DRIVER_VERSION "v0.96"
 103 #define DRIVER_AUTHOR "Juergen Stuber <starblue@sourceforge.net>"
 104 #define DRIVER_DESC "LEGO USB Tower Driver"
 105
 106 /* Module parameters */
 107 module_param(debug, int, S_IRUGO | S_IWUSR);
 108 MODULE_PARM_DESC(debug, "Debug enabled or not");
 109
 110 /* The defaults are chosen to work with the latest versions of leJOS and NQC.
 111  */
 112
 113 /* Some legacy software likes to receive packets in one piece.
 114  * In this case read_buffer_size should exceed the maximal packet length
 115  * (417 for datalog uploads), and packet_timeout should be set.
 116  */
 117 static int read_buffer_size = 480;
 118 module_param(read_buffer_size, int, 0);
 119 MODULE_PARM_DESC(read_buffer_size, "Read buffer size");
 120
 121 /* Some legacy software likes to send packets in one piece.
 122  * In this case write_buffer_size should exceed the maximal packet length
 123  * (417 for firmware and program downloads).
 124  * A problem with long writes is that the following read may time out
 125  * if the software is not prepared to wait long enough.
 126  */
 127 static int write_buffer_size = 480;
 128 module_param(write_buffer_size, int, 0);
 129 MODULE_PARM_DESC(write_buffer_size, "Write buffer size");
 130
 131 /* Some legacy software expects reads to contain whole LASM packets.
 132  * To achieve this, characters which arrive before a packet timeout
 133  * occurs will be returned in a single read operation.
 134  * A problem with long reads is that the software may time out
 135  * if it is not prepared to wait long enough.
 136  * The packet timeout should be greater than the time between the
 137  * reception of subsequent characters, which should arrive about
 138  * every 5ms for the standard 2400 baud.
 139  * Set it to 0 to disable.
 140  */
 141 static int packet_timeout = 50;
 142 module_param(packet_timeout, int, 0);
 143 MODULE_PARM_DESC(packet_timeout, "Packet timeout in ms");
 144
 145 /* Some legacy software expects blocking reads to time out.
 146  * Timeout occurs after the specified time of read and write inactivity.
 147  * Set it to 0 to disable.
 148  */
 149 static int read_timeout = 200;
 150 module_param(read_timeout, int, 0);
 151 MODULE_PARM_DESC(read_timeout, "Read timeout in ms");
 152
 153 /* As of kernel version 2.6.4 ehci-hcd uses an
 154  * "only one interrupt transfer per frame" shortcut
 155  * to simplify the scheduling of periodic transfers.
 156  * This conflicts with our standard 1ms intervals for in and out URBs.
 157  * We use default intervals of 2ms for in and 8ms for out transfers,
 158  * which is fast enough for 2400 baud and allows a small additional load.
 159  * Increase the interval to allow more devices that do interrupt transfers,
 160  * or set to 0 to use the standard interval from the endpoint descriptors.
 161  */
 162 static int interrupt_in_interval = 2;
 163 module_param(interrupt_in_interval, int, 0);
 164 MODULE_PARM_DESC(interrupt_in_interval, "Interrupt in interval in ms");
 165
 166 static int interrupt_out_interval = 8;
 167 module_param(interrupt_out_interval, int, 0);
 168 MODULE_PARM_DESC(interrupt_out_interval, "Interrupt out interval in ms");
 169
 170 /* Define these values to match your device */
 171 #define LEGO_USB_TOWER_VENDOR_ID        0x0694
 172 #define LEGO_USB_TOWER_PRODUCT_ID       0x0001
 173
 174 /* Vendor requests */
 175 #define LEGO_USB_TOWER_REQUEST_RESET            0x04
 176 #define LEGO_USB_TOWER_REQUEST_GET_VERSION      0xFD
 177
 178 struct tower_reset_reply {
 179         __le16 size;            /* little-endian */
 180         __u8 err_code;
 181         __u8 spare;
 182 } __attribute__ ((packed));
 183
 184 struct tower_get_version_reply {
 185         __le16 size;            /* little-endian */
 186         __u8 err_code;
 187         __u8 spare;
 188         __u8 major;
 189         __u8 minor;
 190         __le16 build_no;                /* little-endian */
 191 } __attribute__ ((packed));
 192
 193
 194 /* table of devices that work with this driver */
 195 static struct usb_device_id tower_table [] = {
 196         { USB_DEVICE(LEGO_USB_TOWER_VENDOR_ID, LEGO_USB_TOWER_PRODUCT_ID) },
 197         { }                                     /* Terminating entry */
 198 };
 199
 200 MODULE_DEVICE_TABLE (usb, tower_table);
 201 static DEFINE_MUTEX(open_disc_mutex);
 202
 203 #define LEGO_USB_TOWER_MINOR_BASE       160
 204
 205
 206 /* Structure to hold all of our device specific stuff */
 207 struct lego_usb_tower {
 208         struct mutex            lock;           /* locks this structure */
 209         struct usb_device*      udev;           /* save off the usb device pointer */
 210         unsigned char           minor;          /* the starting minor number for this device */
 211
 212         int                     open_count;     /* number of times this port has been opened */
 213
 214         char*                   read_buffer;
 215         size_t                  read_buffer_length; /* this much came in */
 216         size_t                  read_packet_length; /* this much will be returned on read */
 217         spinlock_t              read_buffer_lock;
 218         int                     packet_timeout_jiffies;
 219         unsigned long           read_last_arrival;
 220
 221         wait_queue_head_t       read_wait;
 222         wait_queue_head_t       write_wait;
 223
 224         char*                   interrupt_in_buffer;
 225         struct usb_endpoint_descriptor* interrupt_in_endpoint;
 226         struct urb*             interrupt_in_urb;
 227         int                     interrupt_in_interval;
 228         int                     interrupt_in_running;
 229         int                     interrupt_in_done;
 230
 231         char*                   interrupt_out_buffer;
 232         struct usb_endpoint_descriptor* interrupt_out_endpoint;
 233         struct urb*             interrupt_out_urb;
 234         int                     interrupt_out_interval;
 235         int                     interrupt_out_busy;
 236
 237 };
 238
 239
 240 /* local function prototypes */
 241 static ssize_t tower_read       (struct file *file, char __user *buffer, size_t count, loff_t *ppos);
 242 static ssize_t tower_write      (struct file *file, const char __user *buffer, size_t count, loff_t *ppos);
 243 static inline void tower_delete (struct lego_usb_tower *dev);
 244 static int tower_open           (struct inode *inode, struct file *file);
 245 static int tower_release        (struct inode *inode, struct file *file);
 246 static unsigned int tower_poll  (struct file *file, poll_table *wait);
 247 static loff_t tower_llseek      (struct file *file, loff_t off, int whence);
 248
 249 static void tower_abort_transfers (struct lego_usb_tower *dev);
 250 static void tower_check_for_read_packet (struct lego_usb_tower *dev);
 251 static void tower_interrupt_in_callback (struct urb *urb);
 252 static void tower_interrupt_out_callback (struct urb *urb);
 253
 254 static int  tower_probe (struct usb_interface *interface, const struct usb_device_id *id);
 255 static void tower_disconnect    (struct usb_interface *interface);
 256
 257
 258 /* file operations needed when we register this driver */
 259 static const struct file_operations tower_fops = {
 260         .owner =        THIS_MODULE,
 261         .read  =        tower_read,
 262         .write =        tower_write,
 263         .open =         tower_open,
 264         .release =      tower_release,
 265         .poll =         tower_poll,
 266         .llseek =       tower_llseek,
 267 };
 268
 269 /*
 270  * usb class driver info in order to get a minor number from the usb core,
 271  * and to have the device registered with the driver core
 272  */
 273 static struct usb_class_driver tower_class = {
 274         .name =         "legousbtower%d",
 275         .fops =         &tower_fops,
 276         .minor_base =   LEGO_USB_TOWER_MINOR_BASE,
 277 };
 278
 279
 280 /* usb specific object needed to register this driver with the usb subsystem */
 281 static struct usb_driver tower_driver = {
 282         .name =         "legousbtower",
 283         .probe =        tower_probe,
 284         .disconnect =   tower_disconnect,
 285         .id_table =     tower_table,
 286 };
 287
 288
 289 /**
 290  *      lego_usb_tower_debug_data
 291  */
 292 static inline void lego_usb_tower_debug_data (int level, const char *function, int size, const unsigned char *data)
 293 {
 294         int i;
 295
 296         if (debug < level)
 297                 return;
 298
 299         printk (KERN_DEBUG __FILE__": %s - length = %d, data = ", function, size);
 300         for (i = 0; i < size; ++i) {
 301                 printk ("%.2x ", data[i]);
 302         }
 303         printk ("\n");
 304 }
 305
 306
 307 /**
 308  *      tower_delete
 309  */
 310 static inline void tower_delete (struct lego_usb_tower *dev)
 311 {
 312         dbg(2, "%s: enter", __FUNCTION__);
 313
 314         tower_abort_transfers (dev);
 315
 316         /* free data structures */
 317         usb_free_urb(dev->interrupt_in_urb);
 318         usb_free_urb(dev->interrupt_out_urb);
 319         kfree (dev->read_buffer);
 320         kfree (dev->interrupt_in_buffer);
 321         kfree (dev->interrupt_out_buffer);
 322         kfree (dev);
 323
 324         dbg(2, "%s: leave", __FUNCTION__);
 325 }
 326
 327
 328 /**
 329  *      tower_open
 330  */
 331 static int tower_open (struct inode *inode, struct file *file)
 332 {
 333         struct lego_usb_tower *dev = NULL;
 334         int subminor;
 335         int retval = 0;
 336         struct usb_interface *interface;
 337         struct tower_reset_reply reset_reply;
 338         int result;
 339
 340         dbg(2, "%s: enter", __FUNCTION__);
 341
 342         nonseekable_open(inode, file);
 343         subminor = iminor(inode);
 344
 345         interface = usb_find_interface (&tower_driver, subminor);
 346
 347         if (!interface) {
 348                 err ("%s - error, can't find device for minor %d",
 349                      __FUNCTION__, subminor);
 350                 retval = -ENODEV;
 351                 goto exit;
 352         }
 353
 354         mutex_lock(&open_disc_mutex);
 355         dev = usb_get_intfdata(interface);
 356
 357         if (!dev) {
 358                 mutex_unlock(&open_disc_mutex);
 359                 retval = -ENODEV;
 360                 goto exit;
 361         }
 362
 363         /* lock this device */
 364         if (mutex_lock_interruptible(&dev->lock)) {
 365                 mutex_unlock(&open_disc_mutex);
 366                 retval = -ERESTARTSYS;
 367                 goto exit;
 368         }
 369
 370
 371         /* allow opening only once */
 372         if (dev->open_count) {
 373                 mutex_unlock(&open_disc_mutex);
 374                 retval = -EBUSY;
 375                 goto unlock_exit;
 376         }
 377         dev->open_count = 1;
 378         mutex_unlock(&open_disc_mutex);
 379
 380         /* reset the tower */
 381         result = usb_control_msg (dev->udev,
 382                                   usb_rcvctrlpipe(dev->udev, 0),
 383                                   LEGO_USB_TOWER_REQUEST_RESET,
 384                                   USB_TYPE_VENDOR | USB_DIR_IN | USB_RECIP_DEVICE,
 385                                   0,
 386                                   0,
 387                                   &reset_reply,
 388                                   sizeof(reset_reply),
 389                                   1000);
 390         if (result < 0) {
 391                 err("LEGO USB Tower reset control request failed");
 392                 retval = result;
 393                 goto unlock_exit;
 394         }
 395
 396         /* initialize in direction */
 397         dev->read_buffer_length = 0;
 398         dev->read_packet_length = 0;
 399         usb_fill_int_urb (dev->interrupt_in_urb,
 400                           dev->udev,
 401                           usb_rcvintpipe(dev->udev, dev->interrupt_in_endpoint->bEndpointAddress),
 402                           dev->interrupt_in_buffer,
 403                           le16_to_cpu(dev->interrupt_in_endpoint->wMaxPacketSize),
 404                           tower_interrupt_in_callback,
 405                           dev,
 406                           dev->interrupt_in_interval);
 407
 408         dev->interrupt_in_running = 1;
 409         dev->interrupt_in_done = 0;
 410         mb();
 411
 412         retval = usb_submit_urb (dev->interrupt_in_urb, GFP_KERNEL);
 413         if (retval) {
 414                 err("Couldn't submit interrupt_in_urb %d", retval);
 415                 dev->interrupt_in_running = 0;
 416                 dev->open_count = 0;
 417                 goto unlock_exit;
 418         }
 419
 420         /* save device in the file's private structure */
 421         file->private_data = dev;
 422
 423 unlock_exit:
 424         mutex_unlock(&dev->lock);
 425
 426 exit:
 427         dbg(2, "%s: leave, return value %d ", __FUNCTION__, retval);
 428
 429         return retval;
 430 }
 431
 432 /**
 433  *      tower_release
 434  */
 435 static int tower_release (struct inode *inode, struct file *file)
 436 {
 437         struct lego_usb_tower *dev;
 438         int retval = 0;
 439
 440         dbg(2, "%s: enter", __FUNCTION__);
 441
 442         dev = (struct lego_usb_tower *)file->private_data;
 443
 444         if (dev == NULL) {
 445                 dbg(1, "%s: object is NULL", __FUNCTION__);
 446                 retval = -ENODEV;
 447                 goto exit_nolock;
 448         }
 449
 450         mutex_lock(&open_disc_mutex);
 451         if (mutex_lock_interruptible(&dev->lock)) {
 452                 retval = -ERESTARTSYS;
 453                 goto exit;
 454         }
 455
 456         if (dev->open_count != 1) {
 457                 dbg(1, "%s: device not opened exactly once", __FUNCTION__);
 458                 retval = -ENODEV;
 459                 goto unlock_exit;
 460         }
 461         if (dev->udev == NULL) {
 462                 /* the device was unplugged before the file was released */
 463
 464                 /* unlock here as tower_delete frees dev */
 465                 mutex_unlock(&dev->lock);
 466                 tower_delete (dev);
 467                 goto exit;
 468         }
 469
 470         /* wait until write transfer is finished */
 471         if (dev->interrupt_out_busy) {
 472                 wait_event_interruptible_timeout (dev->write_wait, !dev->interrupt_out_busy, 2 * HZ);
 473         }
 474         tower_abort_transfers (dev);
 475         dev->open_count = 0;
 476
 477 unlock_exit:
 478         mutex_unlock(&dev->lock);
 479
 480 exit:
 481         mutex_unlock(&open_disc_mutex);
 482 exit_nolock:
 483         dbg(2, "%s: leave, return value %d", __FUNCTION__, retval);
 484         return retval;
 485 }
 486
 487
 488 /**
 489  *      tower_abort_transfers
 490  *      aborts transfers and frees associated data structures
 491  */
 492 static void tower_abort_transfers (struct lego_usb_tower *dev)
 493 {
 494         dbg(2, "%s: enter", __FUNCTION__);
 495
 496         if (dev == NULL) {
 497                 dbg(1, "%s: dev is null", __FUNCTION__);
 498                 goto exit;
 499         }
 500
 501         /* shutdown transfer */
 502         if (dev->interrupt_in_running) {
 503                 dev->interrupt_in_running = 0;
 504                 mb();
 505                 if (dev->udev)
 506                         usb_kill_urb (dev->interrupt_in_urb);
 507         }
 508         if (dev->interrupt_out_busy && dev->udev)
 509                 usb_kill_urb(dev->interrupt_out_urb);
 510
 511 exit:
 512         dbg(2, "%s: leave", __FUNCTION__);
 513 }
 514
 515
 516 /**
 517  *      tower_check_for_read_packet
 518  *
 519  *      To get correct semantics for signals and non-blocking I/O
 520  *      with packetizing we pretend not to see any data in the read buffer
 521  *      until it has been there unchanged for at least
 522  *      dev->packet_timeout_jiffies, or until the buffer is full.
 523  */
 524 static void tower_check_for_read_packet (struct lego_usb_tower *dev)
 525 {
 526         spin_lock_irq (&dev->read_buffer_lock);
 527         if (!packet_timeout
 528             || time_after(jiffies, dev->read_last_arrival + dev->packet_timeout_jiffies)
 529             || dev->read_buffer_length == read_buffer_size) {
 530                 dev->read_packet_length = dev->read_buffer_length;
 531         }
 532         dev->interrupt_in_done = 0;
 533         spin_unlock_irq (&dev->read_buffer_lock);
 534 }
 535
 536
 537 /**
 538  *      tower_poll
 539  */
 540 static unsigned int tower_poll (struct file *file, poll_table *wait)
 541 {
 542         struct lego_usb_tower *dev;
 543         unsigned int mask = 0;
 544
 545         dbg(2, "%s: enter", __FUNCTION__);
 546
 547         dev = file->private_data;
 548
 549         poll_wait(file, &dev->read_wait, wait);
 550         poll_wait(file, &dev->write_wait, wait);
 551
 552         tower_check_for_read_packet(dev);
 553         if (dev->read_packet_length > 0) {
 554                 mask |= POLLIN | POLLRDNORM;
 555         }
 556         if (!dev->interrupt_out_busy) {
 557                 mask |= POLLOUT | POLLWRNORM;
 558         }
 559
 560         dbg(2, "%s: leave, mask = %d", __FUNCTION__, mask);
 561
 562         return mask;
 563 }
 564
 565
 566 /**
 567  *      tower_llseek
 568  */
 569 static loff_t tower_llseek (struct file *file, loff_t off, int whence)
 570 {
 571         return -ESPIPE;         /* unseekable */
 572 }
 573
 574
 575 /**
 576  *      tower_read
 577  */
 578 static ssize_t tower_read (struct file *file, char __user *buffer, size_t count, loff_t *ppos)
 579 {
 580         struct lego_usb_tower *dev;
 581         size_t bytes_to_read;
 582         int i;
 583         int retval = 0;
 584         unsigned long timeout = 0;
 585
 586         dbg(2, "%s: enter, count = %Zd", __FUNCTION__, count);
 587
 588         dev = (struct lego_usb_tower *)file->private_data;
 589
 590         /* lock this object */
 591         if (mutex_lock_interruptible(&dev->lock)) {
 592                 retval = -ERESTARTSYS;
 593                 goto exit;
 594         }
 595
 596         /* verify that the device wasn't unplugged */
 597         if (dev->udev == NULL) {
 598                 retval = -ENODEV;
 599                 err("No device or device unplugged %d", retval);
 600                 goto unlock_exit;
 601         }
 602
 603         /* verify that we actually have some data to read */
 604         if (count == 0) {
 605                 dbg(1, "%s: read request of 0 bytes", __FUNCTION__);
 606                 goto unlock_exit;
 607         }
 608
 609         if (read_timeout) {
 610                 timeout = jiffies + read_timeout * HZ / 1000;
 611         }
 612
 613         /* wait for data */
 614         tower_check_for_read_packet (dev);
 615         while (dev->read_packet_length == 0) {
 616                 if (file->f_flags & O_NONBLOCK) {
 617                         retval = -EAGAIN;
 618                         goto unlock_exit;
 619                 }
 620                 retval = wait_event_interruptible_timeout(dev->read_wait, dev->interrupt_in_done, dev->packet_timeout_jiffies);
 621                 if (retval < 0) {
 622                         goto unlock_exit;
 623                 }
 624
 625                 /* reset read timeout during read or write activity */
 626                 if (read_timeout
 627                     && (dev->read_buffer_length || dev->interrupt_out_busy)) {
 628                         timeout = jiffies + read_timeout * HZ / 1000;
 629                 }
 630                 /* check for read timeout */
 631                 if (read_timeout && time_after (jiffies, timeout)) {
 632                         retval = -ETIMEDOUT;
 633                         goto unlock_exit;
 634                 }
 635                 tower_check_for_read_packet (dev);
 636         }
 637
 638         /* copy the data from read_buffer into userspace */
 639         bytes_to_read = min(count, dev->read_packet_length);
 640
 641         if (copy_to_user (buffer, dev->read_buffer, bytes_to_read)) {
 642                 retval = -EFAULT;
 643                 goto unlock_exit;
 644         }
 645
 646         spin_lock_irq (&dev->read_buffer_lock);
 647         dev->read_buffer_length -= bytes_to_read;
 648         dev->read_packet_length -= bytes_to_read;
 649         for (i=0; i<dev->read_buffer_length; i++) {
 650                 dev->read_buffer[i] = dev->read_buffer[i+bytes_to_read];
 651         }
 652         spin_unlock_irq (&dev->read_buffer_lock);
 653
 654         retval = bytes_to_read;
 655
 656 unlock_exit:
 657         /* unlock the device */
 658         mutex_unlock(&dev->lock);
 659
 660 exit:
 661         dbg(2, "%s: leave, return value %d", __FUNCTION__, retval);
 662         return retval;
 663 }
 664
 665
 666 /**
 667  *      tower_write
 668  */
 669 static ssize_t tower_write (struct file *file, const char __user *buffer, size_t count, loff_t *ppos)
 670 {
 671         struct lego_usb_tower *dev;
 672         size_t bytes_to_write;
 673         int retval = 0;
 674
 675         dbg(2, "%s: enter, count = %Zd", __FUNCTION__, count);
 676
 677         dev = (struct lego_usb_tower *)file->private_data;
 678
 679         /* lock this object */
 680         if (mutex_lock_interruptible(&dev->lock)) {
 681                 retval = -ERESTARTSYS;
 682                 goto exit;
 683         }
 684
 685         /* verify that the device wasn't unplugged */
 686         if (dev->udev == NULL) {
 687                 retval = -ENODEV;
 688                 err("No device or device unplugged %d", retval);
 689                 goto unlock_exit;
 690         }
 691
 692         /* verify that we actually have some data to write */
 693         if (count == 0) {
 694                 dbg(1, "%s: write request of 0 bytes", __FUNCTION__);
 695                 goto unlock_exit;
 696         }
 697
 698         /* wait until previous transfer is finished */
 699         while (dev->interrupt_out_busy) {
 700                 if (file->f_flags & O_NONBLOCK) {
 701                         retval = -EAGAIN;
 702                         goto unlock_exit;
 703                 }
 704                 retval = wait_event_interruptible (dev->write_wait, !dev->interrupt_out_busy);
 705                 if (retval) {
 706                         goto unlock_exit;
 707                 }
 708         }
 709
 710         /* write the data into interrupt_out_buffer from userspace */
 711         bytes_to_write = min_t(int, count, write_buffer_size);
 712         dbg(4, "%s: count = %Zd, bytes_to_write = %Zd", __FUNCTION__, count, bytes_to_write);
 713
 714         if (copy_from_user (dev->interrupt_out_buffer, buffer, bytes_to_write)) {
 715                 retval = -EFAULT;
 716                 goto unlock_exit;
 717         }
 718
 719         /* send off the urb */
 720         usb_fill_int_urb(dev->interrupt_out_urb,
 721                          dev->udev,
 722                          usb_sndintpipe(dev->udev, dev->interrupt_out_endpoint->bEndpointAddress),
 723                          dev->interrupt_out_buffer,
 724                          bytes_to_write,
 725                          tower_interrupt_out_callback,
 726                          dev,
 727                          dev->interrupt_out_interval);
 728
 729         dev->interrupt_out_busy = 1;
 730         wmb();
 731
 732         retval = usb_submit_urb (dev->interrupt_out_urb, GFP_KERNEL);
 733         if (retval) {
 734                 dev->interrupt_out_busy = 0;
 735                 err("Couldn't submit interrupt_out_urb %d", retval);
 736                 goto unlock_exit;
 737         }
 738         retval = bytes_to_write;
 739
 740 unlock_exit:
 741         /* unlock the device */
 742         mutex_unlock(&dev->lock);
 743
 744 exit:
 745         dbg(2, "%s: leave, return value %d", __FUNCTION__, retval);
 746
 747         return retval;
 748 }
 749
 750
 751 /**
 752  *      tower_interrupt_in_callback
 753  */
 754 static void tower_interrupt_in_callback (struct urb *urb)
 755 {
 756         struct lego_usb_tower *dev = (struct lego_usb_tower *)urb->context;
 757         int status = urb->status;
 758         int retval;
 759
 760         dbg(4, "%s: enter, status %d", __FUNCTION__, status);
 761
 762         lego_usb_tower_debug_data(5, __FUNCTION__, urb->actual_length, urb->transfer_buffer);
 763
 764         if (status) {
 765                 if (status == -ENOENT ||
 766                     status == -ECONNRESET ||
 767                     status == -ESHUTDOWN) {
 768                         goto exit;
 769                 } else {
 770                         dbg(1, "%s: nonzero status received: %d", __FUNCTION__, status);
 771                         goto resubmit; /* maybe we can recover */
 772                 }
 773         }
 774
 775         if (urb->actual_length > 0) {
 776                 spin_lock (&dev->read_buffer_lock);
 777                 if (dev->read_buffer_length + urb->actual_length < read_buffer_size) {
 778                         memcpy (dev->read_buffer + dev->read_buffer_length,
 779                                 dev->interrupt_in_buffer,
 780                                 urb->actual_length);
 781                         dev->read_buffer_length += urb->actual_length;
 782                         dev->read_last_arrival = jiffies;
 783                         dbg(3, "%s: received %d bytes", __FUNCTION__, urb->actual_length);
 784                 } else {
 785                         printk(KERN_WARNING "%s: read_buffer overflow, %d bytes dropped", __FUNCTION__, urb->actual_length);
 786                 }
 787                 spin_unlock (&dev->read_buffer_lock);
 788         }
 789
 790 resubmit:
 791         /* resubmit if we're still running */
 792         if (dev->interrupt_in_running && dev->udev) {
 793                 retval = usb_submit_urb (dev->interrupt_in_urb, GFP_ATOMIC);
 794                 if (retval) {
 795                         err("%s: usb_submit_urb failed (%d)", __FUNCTION__, retval);
 796                 }
 797         }
 798
 799 exit:
 800         dev->interrupt_in_done = 1;
 801         wake_up_interruptible (&dev->read_wait);
 802
 803         lego_usb_tower_debug_data(5, __FUNCTION__, urb->actual_length, urb->transfer_buffer);
 804         dbg(4, "%s: leave, status %d", __FUNCTION__, status);
 805 }
 806
 807
 808 /**
 809  *      tower_interrupt_out_callback
 810  */
 811 static void tower_interrupt_out_callback (struct urb *urb)
 812 {
 813         struct lego_usb_tower *dev = (struct lego_usb_tower *)urb->context;
 814         int status = urb->status;
 815
 816         dbg(4, "%s: enter, status %d", __FUNCTION__, status);
 817         lego_usb_tower_debug_data(5, __FUNCTION__, urb->actual_length, urb->transfer_buffer);
 818
 819         /* sync/async unlink faults aren't errors */
 820         if (status && !(status == -ENOENT ||
 821                         status == -ECONNRESET ||
 822                         status == -ESHUTDOWN)) {
 823                 dbg(1, "%s - nonzero write bulk status received: %d",
 824                     __FUNCTION__, status);
 825         }
 826
 827         dev->interrupt_out_busy = 0;
 828         wake_up_interruptible(&dev->write_wait);
 829
 830         lego_usb_tower_debug_data(5, __FUNCTION__, urb->actual_length, urb->transfer_buffer);
 831         dbg(4, "%s: leave, status %d", __FUNCTION__, status);
 832 }
 833
 834
 835 /**
 836  *      tower_probe
 837  *
 838  *      Called by the usb core when a new device is connected that it thinks
 839  *      this driver might be interested in.
 840  */
 841 static int tower_probe (struct usb_interface *interface, const struct usb_device_id *id)
 842 {
 843         struct usb_device *udev = interface_to_usbdev(interface);
 844         struct lego_usb_tower *dev = NULL;
 845         struct usb_host_interface *iface_desc;
 846         struct usb_endpoint_descriptor* endpoint;
 847         struct tower_get_version_reply get_version_reply;
 848         int i;
 849         int retval = -ENOMEM;
 850         int result;
 851
 852         dbg(2, "%s: enter", __FUNCTION__);
 853
 854         if (udev == NULL) {
 855                 info ("udev is NULL.");
 856         }
 857
 858         /* allocate memory for our device state and initialize it */
 859
 860         dev = kmalloc (sizeof(struct lego_usb_tower), GFP_KERNEL);
 861
 862         if (dev == NULL) {
 863                 err ("Out of memory");
 864                 goto exit;
 865         }
 866
 867         mutex_init(&dev->lock);
 868
 869         dev->udev = udev;
 870         dev->open_count = 0;
 871
 872         dev->read_buffer = NULL;
 873         dev->read_buffer_length = 0;
 874         dev->read_packet_length = 0;
 875         spin_lock_init (&dev->read_buffer_lock);
 876         dev->packet_timeout_jiffies = packet_timeout * HZ / 1000;
 877         dev->read_last_arrival = jiffies;
 878
 879         init_waitqueue_head (&dev->read_wait);
 880         init_waitqueue_head (&dev->write_wait);
 881
 882         dev->interrupt_in_buffer = NULL;
 883         dev->interrupt_in_endpoint = NULL;
 884         dev->interrupt_in_urb = NULL;
 885         dev->interrupt_in_running = 0;
 886         dev->interrupt_in_done = 0;
 887
 888         dev->interrupt_out_buffer = NULL;
 889         dev->interrupt_out_endpoint = NULL;
 890         dev->interrupt_out_urb = NULL;
 891         dev->interrupt_out_busy = 0;
 892
 893         iface_desc = interface->cur_altsetting;
 894
 895         /* set up the endpoint information */
 896         for (i = 0; i < iface_desc->desc.bNumEndpoints; ++i) {
 897                 endpoint = &iface_desc->endpoint[i].desc;
 898
 899                 if (usb_endpoint_xfer_int(endpoint)) {
 900                         if (usb_endpoint_dir_in(endpoint))
 901                                 dev->interrupt_in_endpoint = endpoint;
 902                         else
 903                                 dev->interrupt_out_endpoint = endpoint;
 904                 }
 905         }
 906         if(dev->interrupt_in_endpoint == NULL) {
 907                 err("interrupt in endpoint not found");
 908                 goto error;
 909         }
 910         if (dev->interrupt_out_endpoint == NULL) {
 911                 err("interrupt out endpoint not found");
 912                 goto error;
 913         }
 914
 915         dev->read_buffer = kmalloc (read_buffer_size, GFP_KERNEL);
 916         if (!dev->read_buffer) {
 917                 err("Couldn't allocate read_buffer");
 918                 goto error;
 919         }
 920         dev->interrupt_in_buffer = kmalloc (le16_to_cpu(dev->interrupt_in_endpoint->wMaxPacketSize), GFP_KERNEL);
 921         if (!dev->interrupt_in_buffer) {
 922                 err("Couldn't allocate interrupt_in_buffer");
 923                 goto error;
 924         }
 925         dev->interrupt_in_urb = usb_alloc_urb(0, GFP_KERNEL);
 926         if (!dev->interrupt_in_urb) {
 927                 err("Couldn't allocate interrupt_in_urb");
 928                 goto error;
 929         }
 930         dev->interrupt_out_buffer = kmalloc (write_buffer_size, GFP_KERNEL);
 931         if (!dev->interrupt_out_buffer) {
 932                 err("Couldn't allocate interrupt_out_buffer");
 933                 goto error;
 934         }
 935         dev->interrupt_out_urb = usb_alloc_urb(0, GFP_KERNEL);
 936         if (!dev->interrupt_out_urb) {
 937                 err("Couldn't allocate interrupt_out_urb");
 938                 goto error;
 939         }
 940         dev->interrupt_in_interval = interrupt_in_interval ? interrupt_in_interval : dev->interrupt_in_endpoint->bInterval;
 941         dev->interrupt_out_interval = interrupt_out_interval ? interrupt_out_interval : dev->interrupt_out_endpoint->bInterval;
 942
 943         /* we can register the device now, as it is ready */
 944         usb_set_intfdata (interface, dev);
 945
 946         retval = usb_register_dev (interface, &tower_class);
 947
 948         if (retval) {
 949                 /* something prevented us from registering this driver */
 950                 err ("Not able to get a minor for this device.");
 951                 usb_set_intfdata (interface, NULL);
 952                 goto error;
 953         }
 954         dev->minor = interface->minor;
 955
 956         /* let the user know what node this device is now attached to */
 957         info ("LEGO USB Tower #%d now attached to major %d minor %d", (dev->minor - LEGO_USB_TOWER_MINOR_BASE), USB_MAJOR, dev->minor);
 958
 959         /* get the firmware version and log it */
 960         result = usb_control_msg (udev,
 961                                   usb_rcvctrlpipe(udev, 0),
 962                                   LEGO_USB_TOWER_REQUEST_GET_VERSION,
 963                                   USB_TYPE_VENDOR | USB_DIR_IN | USB_RECIP_DEVICE,
 964                                   0,
 965                                   0,
 966                                   &get_version_reply,
 967                                   sizeof(get_version_reply),
 968                                   1000);
 969         if (result < 0) {
 970                 err("LEGO USB Tower get version control request failed");
 971                 retval = result;
 972                 goto error;
 973         }
 974         info("LEGO USB Tower firmware version is %d.%d build %d",
 975              get_version_reply.major,
 976              get_version_reply.minor,
 977              le16_to_cpu(get_version_reply.build_no));
 978
 979
 980 exit:
 981         dbg(2, "%s: leave, return value 0x%.8lx (dev)", __FUNCTION__, (long) dev);
 982
 983         return retval;
 984
 985 error:
 986         tower_delete(dev);
 987         return retval;
 988 }
 989
 990
 991 /**
 992  *      tower_disconnect
 993  *
 994  *      Called by the usb core when the device is removed from the system.
 995  */
 996 static void tower_disconnect (struct usb_interface *interface)
 997 {
 998         struct lego_usb_tower *dev;
 999         int minor;
1000
1001         dbg(2, "%s: enter", __FUNCTION__);
1002
1003         dev = usb_get_intfdata (interface);
1004         mutex_lock(&open_disc_mutex);
1005         usb_set_intfdata (interface, NULL);
1006
1007         minor = dev->minor;
1008
1009         /* give back our minor */
1010         usb_deregister_dev (interface, &tower_class);
1011
1012         mutex_lock(&dev->lock);
1013         mutex_unlock(&open_disc_mutex);
1014
1015         /* if the device is not opened, then we clean up right now */
1016         if (!dev->open_count) {
1017                 mutex_unlock(&dev->lock);
1018                 tower_delete (dev);
1019         } else {
1020                 dev->udev = NULL;
1021                 mutex_unlock(&dev->lock);
1022         }
1023
1024         info("LEGO USB Tower #%d now disconnected", (minor - LEGO_USB_TOWER_MINOR_BASE));
1025
1026         dbg(2, "%s: leave", __FUNCTION__);
1027 }
1028
1029
1030
1031 /**
1032  *      lego_usb_tower_init
1033  */
1034 static int __init lego_usb_tower_init(void)
1035 {
1036         int result;
1037         int retval = 0;
1038
1039         dbg(2, "%s: enter", __FUNCTION__);
1040
1041         /* register this driver with the USB subsystem */
1042         result = usb_register(&tower_driver);
1043         if (result < 0) {
1044                 err("usb_register failed for the "__FILE__" driver. Error number %d", result);
1045                 retval = -1;
1046                 goto exit;
1047         }
1048
1049         info(DRIVER_DESC " " DRIVER_VERSION);
1050
1051 exit:
1052         dbg(2, "%s: leave, return value %d", __FUNCTION__, retval);
1053
1054         return retval;
1055 }
1056
1057
1058 /**
1059  *      lego_usb_tower_exit
1060  */
1061 static void __exit lego_usb_tower_exit(void)
1062 {
1063         dbg(2, "%s: enter", __FUNCTION__);
1064
1065         /* deregister this driver with the USB subsystem */
1066         usb_deregister (&tower_driver);
1067
1068         dbg(2, "%s: leave", __FUNCTION__);
1069 }
1070
1071 module_init (lego_usb_tower_init);
1072 module_exit (lego_usb_tower_exit);
1073
1074 MODULE_AUTHOR(DRIVER_AUTHOR);
1075 MODULE_DESCRIPTION(DRIVER_DESC);
1076 #ifdef MODULE_LICENSE
1077 MODULE_LICENSE("GPL");
1078 #endif