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/config.h>
  79 #include <linux/kernel.h>
  80 #include <linux/errno.h>
  81 #include <linux/init.h>
  82 #include <linux/slab.h>
  83 #include <linux/module.h>
  84 #include <linux/smp_lock.h>
  85 #include <linux/completion.h>
  86 #include <asm/uaccess.h>
  87 #include <linux/usb.h>
  88 #include <linux/poll.h>
  89
  90
  91 #ifdef CONFIG_USB_DEBUG
  92         static int debug = 4;
  93 #else
  94         static int debug = 0;
  95 #endif
  96
  97 /* Use our own dbg macro */
  98 #undef dbg
  99 #define dbg(lvl, format, arg...) do { if (debug >= lvl) printk(KERN_DEBUG  __FILE__ ": " format "\n", ## arg); } while (0)
 100
 101
 102 /* Version Information */
 103 #define DRIVER_VERSION "v0.96"
 104 #define DRIVER_AUTHOR "Juergen Stuber <starblue@sourceforge.net>"
 105 #define DRIVER_DESC "LEGO USB Tower Driver"
 106
 107 /* Module parameters */
 108 module_param(debug, int, S_IRUGO | S_IWUSR);
 109 MODULE_PARM_DESC(debug, "Debug enabled or not");
 110
 111 /* The defaults are chosen to work with the latest versions of leJOS and NQC.
 112  */
 113
 114 /* Some legacy software likes to receive packets in one piece.
 115  * In this case read_buffer_size should exceed the maximal packet length
 116  * (417 for datalog uploads), and packet_timeout should be set.
 117  */
 118 static int read_buffer_size = 480;
 119 module_param(read_buffer_size, int, 0);
 120 MODULE_PARM_DESC(read_buffer_size, "Read buffer size");
 121
 122 /* Some legacy software likes to send packets in one piece.
 123  * In this case write_buffer_size should exceed the maximal packet length
 124  * (417 for firmware and program downloads).
 125  * A problem with long writes is that the following read may time out
 126  * if the software is not prepared to wait long enough.
 127  */
 128 static int write_buffer_size = 480;
 129 module_param(write_buffer_size, int, 0);
 130 MODULE_PARM_DESC(write_buffer_size, "Write buffer size");
 131
 132 /* Some legacy software expects reads to contain whole LASM packets.
 133  * To achieve this, characters which arrive before a packet timeout
 134  * occurs will be returned in a single read operation.
 135  * A problem with long reads is that the software may time out
 136  * if it is not prepared to wait long enough.
 137  * The packet timeout should be greater than the time between the
 138  * reception of subsequent characters, which should arrive about
 139  * every 5ms for the standard 2400 baud.
 140  * Set it to 0 to disable.
 141  */
 142 static int packet_timeout = 50;
 143 module_param(packet_timeout, int, 0);
 144 MODULE_PARM_DESC(packet_timeout, "Packet timeout in ms");
 145
 146 /* Some legacy software expects blocking reads to time out.
 147  * Timeout occurs after the specified time of read and write inactivity.
 148  * Set it to 0 to disable.
 149  */
 150 static int read_timeout = 200;
 151 module_param(read_timeout, int, 0);
 152 MODULE_PARM_DESC(read_timeout, "Read timeout in ms");
 153
 154 /* As of kernel version 2.6.4 ehci-hcd uses an
 155  * "only one interrupt transfer per frame" shortcut
 156  * to simplify the scheduling of periodic transfers.
 157  * This conflicts with our standard 1ms intervals for in and out URBs.
 158  * We use default intervals of 2ms for in and 8ms for out transfers,
 159  * which is fast enough for 2400 baud and allows a small additional load.
 160  * Increase the interval to allow more devices that do interrupt transfers,
 161  * or set to 0 to use the standard interval from the endpoint descriptors.
 162  */
 163 static int interrupt_in_interval = 2;
 164 module_param(interrupt_in_interval, int, 0);
 165 MODULE_PARM_DESC(interrupt_in_interval, "Interrupt in interval in ms");
 166
 167 static int interrupt_out_interval = 8;
 168 module_param(interrupt_out_interval, int, 0);
 169 MODULE_PARM_DESC(interrupt_out_interval, "Interrupt out interval in ms");
 170
 171 /* Define these values to match your device */
 172 #define LEGO_USB_TOWER_VENDOR_ID        0x0694
 173 #define LEGO_USB_TOWER_PRODUCT_ID       0x0001
 174
 175 /* Vendor requests */
 176 #define LEGO_USB_TOWER_REQUEST_RESET            0x04
 177 #define LEGO_USB_TOWER_REQUEST_GET_VERSION      0xFD
 178
 179 struct tower_reset_reply {
 180         __le16 size;            /* little-endian */
 181         __u8 err_code;
 182         __u8 spare;
 183 } __attribute__ ((packed));
 184
 185 struct tower_get_version_reply {
 186         __le16 size;            /* little-endian */
 187         __u8 err_code;
 188         __u8 spare;
 189         __u8 major;
 190         __u8 minor;
 191         __le16 build_no;                /* little-endian */
 192 } __attribute__ ((packed));
 193
 194
 195 /* table of devices that work with this driver */
 196 static struct usb_device_id tower_table [] = {
 197         { USB_DEVICE(LEGO_USB_TOWER_VENDOR_ID, LEGO_USB_TOWER_PRODUCT_ID) },
 198         { }                                     /* Terminating entry */
 199 };
 200
 201 MODULE_DEVICE_TABLE (usb, tower_table);
 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 semaphore        sem;            /* 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, struct pt_regs *regs);
 252 static void tower_interrupt_out_callback (struct urb *urb, struct pt_regs *regs);
 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 /* prevent races between open() and disconnect */
 259 static DECLARE_MUTEX (disconnect_sem);
 260
 261 /* file operations needed when we register this driver */
 262 static struct file_operations tower_fops = {
 263         .owner =        THIS_MODULE,
 264         .read  =        tower_read,
 265         .write =        tower_write,
 266         .open =         tower_open,
 267         .release =      tower_release,
 268         .poll =         tower_poll,
 269         .llseek =       tower_llseek,
 270 };
 271
 272 /*
 273  * usb class driver info in order to get a minor number from the usb core,
 274  * and to have the device registered with devfs and the driver core
 275  */
 276 static struct usb_class_driver tower_class = {
 277         .name =         "usb/legousbtower%d",
 278         .fops =         &tower_fops,
 279         .mode =         S_IFCHR | S_IRUSR | S_IWUSR | S_IRGRP | S_IWGRP | S_IROTH,
 280         .minor_base =   LEGO_USB_TOWER_MINOR_BASE,
 281 };
 282
 283
 284 /* usb specific object needed to register this driver with the usb subsystem */
 285 static struct usb_driver tower_driver = {
 286         .owner =        THIS_MODULE,
 287         .name =         "legousbtower",
 288         .probe =        tower_probe,
 289         .disconnect =   tower_disconnect,
 290         .id_table =     tower_table,
 291 };
 292
 293
 294 /**
 295  *      lego_usb_tower_debug_data
 296  */
 297 static inline void lego_usb_tower_debug_data (int level, const char *function, int size, const unsigned char *data)
 298 {
 299         int i;
 300
 301         if (debug < level)
 302                 return;
 303
 304         printk (KERN_DEBUG __FILE__": %s - length = %d, data = ", function, size);
 305         for (i = 0; i < size; ++i) {
 306                 printk ("%.2x ", data[i]);
 307         }
 308         printk ("\n");
 309 }
 310
 311
 312 /**
 313  *      tower_delete
 314  */
 315 static inline void tower_delete (struct lego_usb_tower *dev)
 316 {
 317         dbg(2, "%s: enter", __FUNCTION__);
 318
 319         tower_abort_transfers (dev);
 320
 321         /* free data structures */
 322         if (dev->interrupt_in_urb != NULL) {
 323                 usb_free_urb (dev->interrupt_in_urb);
 324         }
 325         if (dev->interrupt_out_urb != NULL) {
 326                 usb_free_urb (dev->interrupt_out_urb);
 327         }
 328         kfree (dev->read_buffer);
 329         kfree (dev->interrupt_in_buffer);
 330         kfree (dev->interrupt_out_buffer);
 331         kfree (dev);
 332
 333         dbg(2, "%s: leave", __FUNCTION__);
 334 }
 335
 336
 337 /**
 338  *      tower_open
 339  */
 340 static int tower_open (struct inode *inode, struct file *file)
 341 {
 342         struct lego_usb_tower *dev = NULL;
 343         int subminor;
 344         int retval = 0;
 345         struct usb_interface *interface;
 346         struct tower_reset_reply reset_reply;
 347         int result;
 348
 349         dbg(2, "%s: enter", __FUNCTION__);
 350
 351         nonseekable_open(inode, file);
 352         subminor = iminor(inode);
 353
 354         down (&disconnect_sem);
 355
 356         interface = usb_find_interface (&tower_driver, subminor);
 357
 358         if (!interface) {
 359                 err ("%s - error, can't find device for minor %d",
 360                      __FUNCTION__, subminor);
 361                 retval = -ENODEV;
 362                 goto unlock_disconnect_exit;
 363         }
 364
 365         dev = usb_get_intfdata(interface);
 366
 367         if (!dev) {
 368                 retval = -ENODEV;
 369                 goto unlock_disconnect_exit;
 370         }
 371
 372         /* lock this device */
 373         if (down_interruptible (&dev->sem)) {
 374                 retval = -ERESTARTSYS;
 375                 goto unlock_disconnect_exit;
 376         }
 377
 378         /* allow opening only once */
 379         if (dev->open_count) {
 380                 retval = -EBUSY;
 381                 goto unlock_exit;
 382         }
 383         dev->open_count = 1;
 384
 385         /* reset the tower */
 386         result = usb_control_msg (dev->udev,
 387                                   usb_rcvctrlpipe(dev->udev, 0),
 388                                   LEGO_USB_TOWER_REQUEST_RESET,
 389                                   USB_TYPE_VENDOR | USB_DIR_IN | USB_RECIP_DEVICE,
 390                                   0,
 391                                   0,
 392                                   &reset_reply,
 393                                   sizeof(reset_reply),
 394                                   1000);
 395         if (result < 0) {
 396                 err("LEGO USB Tower reset control request failed");
 397                 retval = result;
 398                 goto unlock_exit;
 399         }
 400
 401         /* initialize in direction */
 402         dev->read_buffer_length = 0;
 403         dev->read_packet_length = 0;
 404         usb_fill_int_urb (dev->interrupt_in_urb,
 405                           dev->udev,
 406                           usb_rcvintpipe(dev->udev, dev->interrupt_in_endpoint->bEndpointAddress),
 407                           dev->interrupt_in_buffer,
 408                           le16_to_cpu(dev->interrupt_in_endpoint->wMaxPacketSize),
 409                           tower_interrupt_in_callback,
 410                           dev,
 411                           dev->interrupt_in_interval);
 412
 413         dev->interrupt_in_running = 1;
 414         dev->interrupt_in_done = 0;
 415         mb();
 416
 417         retval = usb_submit_urb (dev->interrupt_in_urb, GFP_KERNEL);
 418         if (retval) {
 419                 err("Couldn't submit interrupt_in_urb %d", retval);
 420                 dev->interrupt_in_running = 0;
 421                 dev->open_count = 0;
 422                 goto unlock_exit;
 423         }
 424
 425         /* save device in the file's private structure */
 426         file->private_data = dev;
 427
 428 unlock_exit:
 429         up (&dev->sem);
 430
 431 unlock_disconnect_exit:
 432         up (&disconnect_sem);
 433
 434         dbg(2, "%s: leave, return value %d ", __FUNCTION__, retval);
 435
 436         return retval;
 437 }
 438
 439 /**
 440  *      tower_release
 441  */
 442 static int tower_release (struct inode *inode, struct file *file)
 443 {
 444         struct lego_usb_tower *dev;
 445         int retval = 0;
 446
 447         dbg(2, "%s: enter", __FUNCTION__);
 448
 449         dev = (struct lego_usb_tower *)file->private_data;
 450
 451         if (dev == NULL) {
 452                 dbg(1, "%s: object is NULL", __FUNCTION__);
 453                 retval = -ENODEV;
 454                 goto exit;
 455         }
 456
 457         if (down_interruptible (&dev->sem)) {
 458                 retval = -ERESTARTSYS;
 459                 goto exit;
 460         }
 461
 462         if (dev->open_count != 1) {
 463                 dbg(1, "%s: device not opened exactly once", __FUNCTION__);
 464                 retval = -ENODEV;
 465                 goto unlock_exit;
 466         }
 467         if (dev->udev == NULL) {
 468                 /* the device was unplugged before the file was released */
 469                 up (&dev->sem); /* unlock here as tower_delete frees dev */
 470                 tower_delete (dev);
 471                 goto exit;
 472         }
 473
 474         /* wait until write transfer is finished */
 475         if (dev->interrupt_out_busy) {
 476                 wait_event_interruptible_timeout (dev->write_wait, !dev->interrupt_out_busy, 2 * HZ);
 477         }
 478         tower_abort_transfers (dev);
 479         dev->open_count = 0;
 480
 481 unlock_exit:
 482         up (&dev->sem);
 483
 484 exit:
 485         dbg(2, "%s: leave, return value %d", __FUNCTION__, retval);
 486         return retval;
 487 }
 488
 489
 490 /**
 491  *      tower_abort_transfers
 492  *      aborts transfers and frees associated data structures
 493  */
 494 static void tower_abort_transfers (struct lego_usb_tower *dev)
 495 {
 496         dbg(2, "%s: enter", __FUNCTION__);
 497
 498         if (dev == NULL) {
 499                 dbg(1, "%s: dev is null", __FUNCTION__);
 500                 goto exit;
 501         }
 502
 503         /* shutdown transfer */
 504         if (dev->interrupt_in_running) {
 505                 dev->interrupt_in_running = 0;
 506                 mb();
 507                 if (dev->interrupt_in_urb != NULL && dev->udev) {
 508                         usb_kill_urb (dev->interrupt_in_urb);
 509                 }
 510         }
 511         if (dev->interrupt_out_busy) {
 512                 if (dev->interrupt_out_urb != NULL && dev->udev) {
 513                         usb_kill_urb (dev->interrupt_out_urb);
 514                 }
 515         }
 516
 517 exit:
 518         dbg(2, "%s: leave", __FUNCTION__);
 519 }
 520
 521
 522 /**
 523  *      tower_check_for_read_packet
 524  *
 525  *      To get correct semantics for signals and non-blocking I/O
 526  *      with packetizing we pretend not to see any data in the read buffer
 527  *      until it has been there unchanged for at least
 528  *      dev->packet_timeout_jiffies, or until the buffer is full.
 529  */
 530 static void tower_check_for_read_packet (struct lego_usb_tower *dev)
 531 {
 532         spin_lock_irq (&dev->read_buffer_lock);
 533         if (!packet_timeout
 534             || time_after(jiffies, dev->read_last_arrival + dev->packet_timeout_jiffies)
 535             || dev->read_buffer_length == read_buffer_size) {
 536                 dev->read_packet_length = dev->read_buffer_length;
 537         }
 538         dev->interrupt_in_done = 0;
 539         spin_unlock_irq (&dev->read_buffer_lock);
 540 }
 541
 542
 543 /**
 544  *      tower_poll
 545  */
 546 static unsigned int tower_poll (struct file *file, poll_table *wait)
 547 {
 548         struct lego_usb_tower *dev;
 549         unsigned int mask = 0;
 550
 551         dbg(2, "%s: enter", __FUNCTION__);
 552
 553         dev = file->private_data;
 554
 555         poll_wait(file, &dev->read_wait, wait);
 556         poll_wait(file, &dev->write_wait, wait);
 557
 558         tower_check_for_read_packet(dev);
 559         if (dev->read_packet_length > 0) {
 560                 mask |= POLLIN | POLLRDNORM;
 561         }
 562         if (!dev->interrupt_out_busy) {
 563                 mask |= POLLOUT | POLLWRNORM;
 564         }
 565
 566         dbg(2, "%s: leave, mask = %d", __FUNCTION__, mask);
 567
 568         return mask;
 569 }
 570
 571
 572 /**
 573  *      tower_llseek
 574  */
 575 static loff_t tower_llseek (struct file *file, loff_t off, int whence)
 576 {
 577         return -ESPIPE;         /* unseekable */
 578 }
 579
 580
 581 /**
 582  *      tower_read
 583  */
 584 static ssize_t tower_read (struct file *file, char __user *buffer, size_t count, loff_t *ppos)
 585 {
 586         struct lego_usb_tower *dev;
 587         size_t bytes_to_read;
 588         int i;
 589         int retval = 0;
 590         unsigned long timeout = 0;
 591
 592         dbg(2, "%s: enter, count = %Zd", __FUNCTION__, count);
 593
 594         dev = (struct lego_usb_tower *)file->private_data;
 595
 596         /* lock this object */
 597         if (down_interruptible (&dev->sem)) {
 598                 retval = -ERESTARTSYS;
 599                 goto exit;
 600         }
 601
 602         /* verify that the device wasn't unplugged */
 603         if (dev->udev == NULL) {
 604                 retval = -ENODEV;
 605                 err("No device or device unplugged %d", retval);
 606                 goto unlock_exit;
 607         }
 608
 609         /* verify that we actually have some data to read */
 610         if (count == 0) {
 611                 dbg(1, "%s: read request of 0 bytes", __FUNCTION__);
 612                 goto unlock_exit;
 613         }
 614
 615         if (read_timeout) {
 616                 timeout = jiffies + read_timeout * HZ / 1000;
 617         }
 618
 619         /* wait for data */
 620         tower_check_for_read_packet (dev);
 621         while (dev->read_packet_length == 0) {
 622                 if (file->f_flags & O_NONBLOCK) {
 623                         retval = -EAGAIN;
 624                         goto unlock_exit;
 625                 }
 626                 retval = wait_event_interruptible_timeout(dev->read_wait, dev->interrupt_in_done, dev->packet_timeout_jiffies);
 627                 if (retval < 0) {
 628                         goto unlock_exit;
 629                 }
 630
 631                 /* reset read timeout during read or write activity */
 632                 if (read_timeout
 633                     && (dev->read_buffer_length || dev->interrupt_out_busy)) {
 634                         timeout = jiffies + read_timeout * HZ / 1000;
 635                 }
 636                 /* check for read timeout */
 637                 if (read_timeout && time_after (jiffies, timeout)) {
 638                         retval = -ETIMEDOUT;
 639                         goto unlock_exit;
 640                 }
 641                 tower_check_for_read_packet (dev);
 642         }
 643
 644         /* copy the data from read_buffer into userspace */
 645         bytes_to_read = min(count, dev->read_packet_length);
 646
 647         if (copy_to_user (buffer, dev->read_buffer, bytes_to_read)) {
 648                 retval = -EFAULT;
 649                 goto unlock_exit;
 650         }
 651
 652         spin_lock_irq (&dev->read_buffer_lock);
 653         dev->read_buffer_length -= bytes_to_read;
 654         dev->read_packet_length -= bytes_to_read;
 655         for (i=0; i<dev->read_buffer_length; i++) {
 656                 dev->read_buffer[i] = dev->read_buffer[i+bytes_to_read];
 657         }
 658         spin_unlock_irq (&dev->read_buffer_lock);
 659
 660         retval = bytes_to_read;
 661
 662 unlock_exit:
 663         /* unlock the device */
 664         up (&dev->sem);
 665
 666 exit:
 667         dbg(2, "%s: leave, return value %d", __FUNCTION__, retval);
 668         return retval;
 669 }
 670
 671
 672 /**
 673  *      tower_write
 674  */
 675 static ssize_t tower_write (struct file *file, const char __user *buffer, size_t count, loff_t *ppos)
 676 {
 677         struct lego_usb_tower *dev;
 678         size_t bytes_to_write;
 679         int retval = 0;
 680
 681         dbg(2, "%s: enter, count = %Zd", __FUNCTION__, count);
 682
 683         dev = (struct lego_usb_tower *)file->private_data;
 684
 685         /* lock this object */
 686         if (down_interruptible (&dev->sem)) {
 687                 retval = -ERESTARTSYS;
 688                 goto exit;
 689         }
 690
 691         /* verify that the device wasn't unplugged */
 692         if (dev->udev == NULL) {
 693                 retval = -ENODEV;
 694                 err("No device or device unplugged %d", retval);
 695                 goto unlock_exit;
 696         }
 697
 698         /* verify that we actually have some data to write */
 699         if (count == 0) {
 700                 dbg(1, "%s: write request of 0 bytes", __FUNCTION__);
 701                 goto unlock_exit;
 702         }
 703
 704         /* wait until previous transfer is finished */
 705         while (dev->interrupt_out_busy) {
 706                 if (file->f_flags & O_NONBLOCK) {
 707                         retval = -EAGAIN;
 708                         goto unlock_exit;
 709                 }
 710                 retval = wait_event_interruptible (dev->write_wait, !dev->interrupt_out_busy);
 711                 if (retval) {
 712                         goto unlock_exit;
 713                 }
 714         }
 715
 716         /* write the data into interrupt_out_buffer from userspace */
 717         bytes_to_write = min_t(int, count, write_buffer_size);
 718         dbg(4, "%s: count = %Zd, bytes_to_write = %Zd", __FUNCTION__, count, bytes_to_write);
 719
 720         if (copy_from_user (dev->interrupt_out_buffer, buffer, bytes_to_write)) {
 721                 retval = -EFAULT;
 722                 goto unlock_exit;
 723         }
 724
 725         /* send off the urb */
 726         usb_fill_int_urb(dev->interrupt_out_urb,
 727                          dev->udev,
 728                          usb_sndintpipe(dev->udev, dev->interrupt_out_endpoint->bEndpointAddress),
 729                          dev->interrupt_out_buffer,
 730                          bytes_to_write,
 731                          tower_interrupt_out_callback,
 732                          dev,
 733                          dev->interrupt_out_interval);
 734
 735         dev->interrupt_out_busy = 1;
 736         wmb();
 737
 738         retval = usb_submit_urb (dev->interrupt_out_urb, GFP_KERNEL);
 739         if (retval) {
 740                 dev->interrupt_out_busy = 0;
 741                 err("Couldn't submit interrupt_out_urb %d", retval);
 742                 goto unlock_exit;
 743         }
 744         retval = bytes_to_write;
 745
 746 unlock_exit:
 747         /* unlock the device */
 748         up (&dev->sem);
 749
 750 exit:
 751         dbg(2, "%s: leave, return value %d", __FUNCTION__, retval);
 752
 753         return retval;
 754 }
 755
 756
 757 /**
 758  *      tower_interrupt_in_callback
 759  */
 760 static void tower_interrupt_in_callback (struct urb *urb, struct pt_regs *regs)
 761 {
 762         struct lego_usb_tower *dev = (struct lego_usb_tower *)urb->context;
 763         int retval;
 764
 765         dbg(4, "%s: enter, status %d", __FUNCTION__, urb->status);
 766
 767         lego_usb_tower_debug_data(5, __FUNCTION__, urb->actual_length, urb->transfer_buffer);
 768
 769         if (urb->status) {
 770                 if (urb->status == -ENOENT ||
 771                     urb->status == -ECONNRESET ||
 772                     urb->status == -ESHUTDOWN) {
 773                         goto exit;
 774                 } else {
 775                         dbg(1, "%s: nonzero status received: %d", __FUNCTION__, urb->status);
 776                         goto resubmit; /* maybe we can recover */
 777                 }
 778         }
 779
 780         if (urb->actual_length > 0) {
 781                 spin_lock (&dev->read_buffer_lock);
 782                 if (dev->read_buffer_length + urb->actual_length < read_buffer_size) {
 783                         memcpy (dev->read_buffer + dev->read_buffer_length,
 784                                 dev->interrupt_in_buffer,
 785                                 urb->actual_length);
 786                         dev->read_buffer_length += urb->actual_length;
 787                         dev->read_last_arrival = jiffies;
 788                         dbg(3, "%s: received %d bytes", __FUNCTION__, urb->actual_length);
 789                 } else {
 790                         printk(KERN_WARNING "%s: read_buffer overflow, %d bytes dropped", __FUNCTION__, urb->actual_length);
 791                 }
 792                 spin_unlock (&dev->read_buffer_lock);
 793         }
 794
 795 resubmit:
 796         /* resubmit if we're still running */
 797         if (dev->interrupt_in_running && dev->udev) {
 798                 retval = usb_submit_urb (dev->interrupt_in_urb, GFP_ATOMIC);
 799                 if (retval) {
 800                         err("%s: usb_submit_urb failed (%d)", __FUNCTION__, retval);
 801                 }
 802         }
 803
 804 exit:
 805         dev->interrupt_in_done = 1;
 806         wake_up_interruptible (&dev->read_wait);
 807
 808         lego_usb_tower_debug_data(5, __FUNCTION__, urb->actual_length, urb->transfer_buffer);
 809         dbg(4, "%s: leave, status %d", __FUNCTION__, urb->status);
 810 }
 811
 812
 813 /**
 814  *      tower_interrupt_out_callback
 815  */
 816 static void tower_interrupt_out_callback (struct urb *urb, struct pt_regs *regs)
 817 {
 818         struct lego_usb_tower *dev = (struct lego_usb_tower *)urb->context;
 819
 820         dbg(4, "%s: enter, status %d", __FUNCTION__, urb->status);
 821         lego_usb_tower_debug_data(5, __FUNCTION__, urb->actual_length, urb->transfer_buffer);
 822
 823         /* sync/async unlink faults aren't errors */
 824         if (urb->status && !(urb->status == -ENOENT ||
 825                              urb->status == -ECONNRESET ||
 826                              urb->status == -ESHUTDOWN)) {
 827                 dbg(1, "%s - nonzero write bulk status received: %d",
 828                     __FUNCTION__, urb->status);
 829         }
 830
 831         dev->interrupt_out_busy = 0;
 832         wake_up_interruptible(&dev->write_wait);
 833
 834         lego_usb_tower_debug_data(5, __FUNCTION__, urb->actual_length, urb->transfer_buffer);
 835         dbg(4, "%s: leave, status %d", __FUNCTION__, urb->status);
 836 }
 837
 838
 839 /**
 840  *      tower_probe
 841  *
 842  *      Called by the usb core when a new device is connected that it thinks
 843  *      this driver might be interested in.
 844  */
 845 static int tower_probe (struct usb_interface *interface, const struct usb_device_id *id)
 846 {
 847         struct usb_device *udev = interface_to_usbdev(interface);
 848         struct lego_usb_tower *dev = NULL;
 849         struct usb_host_interface *iface_desc;
 850         struct usb_endpoint_descriptor* endpoint;
 851         struct tower_get_version_reply get_version_reply;
 852         int i;
 853         int retval = -ENOMEM;
 854         int result;
 855
 856         dbg(2, "%s: enter", __FUNCTION__);
 857
 858         if (udev == NULL) {
 859                 info ("udev is NULL.");
 860         }
 861
 862         /* allocate memory for our device state and initialize it */
 863
 864         dev = kmalloc (sizeof(struct lego_usb_tower), GFP_KERNEL);
 865
 866         if (dev == NULL) {
 867                 err ("Out of memory");
 868                 goto exit;
 869         }
 870
 871         init_MUTEX (&dev->sem);
 872
 873         dev->udev = udev;
 874         dev->open_count = 0;
 875
 876         dev->read_buffer = NULL;
 877         dev->read_buffer_length = 0;
 878         dev->read_packet_length = 0;
 879         spin_lock_init (&dev->read_buffer_lock);
 880         dev->packet_timeout_jiffies = packet_timeout * HZ / 1000;
 881         dev->read_last_arrival = jiffies;
 882
 883         init_waitqueue_head (&dev->read_wait);
 884         init_waitqueue_head (&dev->write_wait);
 885
 886         dev->interrupt_in_buffer = NULL;
 887         dev->interrupt_in_endpoint = NULL;
 888         dev->interrupt_in_urb = NULL;
 889         dev->interrupt_in_running = 0;
 890         dev->interrupt_in_done = 0;
 891
 892         dev->interrupt_out_buffer = NULL;
 893         dev->interrupt_out_endpoint = NULL;
 894         dev->interrupt_out_urb = NULL;
 895         dev->interrupt_out_busy = 0;
 896
 897         iface_desc = interface->cur_altsetting;
 898
 899         /* set up the endpoint information */
 900         for (i = 0; i < iface_desc->desc.bNumEndpoints; ++i) {
 901                 endpoint = &iface_desc->endpoint[i].desc;
 902
 903                 if (((endpoint->bEndpointAddress & USB_ENDPOINT_DIR_MASK) == USB_DIR_IN) &&
 904                     ((endpoint->bmAttributes & USB_ENDPOINT_XFERTYPE_MASK) == USB_ENDPOINT_XFER_INT)) {
 905                         dev->interrupt_in_endpoint = endpoint;
 906                 }
 907
 908                 if (((endpoint->bEndpointAddress & USB_ENDPOINT_DIR_MASK) == USB_DIR_OUT) &&
 909                     ((endpoint->bmAttributes & USB_ENDPOINT_XFERTYPE_MASK) == USB_ENDPOINT_XFER_INT)) {
 910                         dev->interrupt_out_endpoint = endpoint;
 911                 }
 912         }
 913         if(dev->interrupt_in_endpoint == NULL) {
 914                 err("interrupt in endpoint not found");
 915                 goto error;
 916         }
 917         if (dev->interrupt_out_endpoint == NULL) {
 918                 err("interrupt out endpoint not found");
 919                 goto error;
 920         }
 921
 922         dev->read_buffer = kmalloc (read_buffer_size, GFP_KERNEL);
 923         if (!dev->read_buffer) {
 924                 err("Couldn't allocate read_buffer");
 925                 goto error;
 926         }
 927         dev->interrupt_in_buffer = kmalloc (le16_to_cpu(dev->interrupt_in_endpoint->wMaxPacketSize), GFP_KERNEL);
 928         if (!dev->interrupt_in_buffer) {
 929                 err("Couldn't allocate interrupt_in_buffer");
 930                 goto error;
 931         }
 932         dev->interrupt_in_urb = usb_alloc_urb(0, GFP_KERNEL);
 933         if (!dev->interrupt_in_urb) {
 934                 err("Couldn't allocate interrupt_in_urb");
 935                 goto error;
 936         }
 937         dev->interrupt_out_buffer = kmalloc (write_buffer_size, GFP_KERNEL);
 938         if (!dev->interrupt_out_buffer) {
 939                 err("Couldn't allocate interrupt_out_buffer");
 940                 goto error;
 941         }
 942         dev->interrupt_out_urb = usb_alloc_urb(0, GFP_KERNEL);
 943         if (!dev->interrupt_out_urb) {
 944                 err("Couldn't allocate interrupt_out_urb");
 945                 goto error;
 946         }
 947         dev->interrupt_in_interval = interrupt_in_interval ? interrupt_in_interval : dev->interrupt_in_endpoint->bInterval;
 948         dev->interrupt_out_interval = interrupt_out_interval ? interrupt_out_interval : dev->interrupt_out_endpoint->bInterval;
 949
 950         /* we can register the device now, as it is ready */
 951         usb_set_intfdata (interface, dev);
 952
 953         retval = usb_register_dev (interface, &tower_class);
 954
 955         if (retval) {
 956                 /* something prevented us from registering this driver */
 957                 err ("Not able to get a minor for this device.");
 958                 usb_set_intfdata (interface, NULL);
 959                 goto error;
 960         }
 961         dev->minor = interface->minor;
 962
 963         /* let the user know what node this device is now attached to */
 964         info ("LEGO USB Tower #%d now attached to major %d minor %d", (dev->minor - LEGO_USB_TOWER_MINOR_BASE), USB_MAJOR, dev->minor);
 965
 966         /* get the firmware version and log it */
 967         result = usb_control_msg (udev,
 968                                   usb_rcvctrlpipe(udev, 0),
 969                                   LEGO_USB_TOWER_REQUEST_GET_VERSION,
 970                                   USB_TYPE_VENDOR | USB_DIR_IN | USB_RECIP_DEVICE,
 971                                   0,
 972                                   0,
 973                                   &get_version_reply,
 974                                   sizeof(get_version_reply),
 975                                   1000);
 976         if (result < 0) {
 977                 err("LEGO USB Tower get version control request failed");
 978                 retval = result;
 979                 goto error;
 980         }
 981         info("LEGO USB Tower firmware version is %d.%d build %d",
 982              get_version_reply.major,
 983              get_version_reply.minor,
 984              le16_to_cpu(get_version_reply.build_no));
 985
 986
 987 exit:
 988         dbg(2, "%s: leave, return value 0x%.8lx (dev)", __FUNCTION__, (long) dev);
 989
 990         return retval;
 991
 992 error:
 993         tower_delete(dev);
 994         return retval;
 995 }
 996
 997
 998 /**
 999  *      tower_disconnect
1000  *
1001  *      Called by the usb core when the device is removed from the system.
1002  */
1003 static void tower_disconnect (struct usb_interface *interface)
1004 {
1005         struct lego_usb_tower *dev;
1006         int minor;
1007
1008         dbg(2, "%s: enter", __FUNCTION__);
1009
1010         down (&disconnect_sem);
1011
1012         dev = usb_get_intfdata (interface);
1013         usb_set_intfdata (interface, NULL);
1014
1015
1016         down (&dev->sem);
1017
1018         minor = dev->minor;
1019
1020         /* give back our minor */
1021         usb_deregister_dev (interface, &tower_class);
1022
1023         /* if the device is not opened, then we clean up right now */
1024         if (!dev->open_count) {
1025                 up (&dev->sem);
1026                 tower_delete (dev);
1027         } else {
1028                 dev->udev = NULL;
1029                 up (&dev->sem);
1030         }
1031
1032         up (&disconnect_sem);
1033
1034         info("LEGO USB Tower #%d now disconnected", (minor - LEGO_USB_TOWER_MINOR_BASE));
1035
1036         dbg(2, "%s: leave", __FUNCTION__);
1037 }
1038
1039
1040
1041 /**
1042  *      lego_usb_tower_init
1043  */
1044 static int __init lego_usb_tower_init(void)
1045 {
1046         int result;
1047         int retval = 0;
1048
1049         dbg(2, "%s: enter", __FUNCTION__);
1050
1051         /* register this driver with the USB subsystem */
1052         result = usb_register(&tower_driver);
1053         if (result < 0) {
1054                 err("usb_register failed for the "__FILE__" driver. Error number %d", result);
1055                 retval = -1;
1056                 goto exit;
1057         }
1058
1059         info(DRIVER_DESC " " DRIVER_VERSION);
1060
1061 exit:
1062         dbg(2, "%s: leave, return value %d", __FUNCTION__, retval);
1063
1064         return retval;
1065 }
1066
1067
1068 /**
1069  *      lego_usb_tower_exit
1070  */
1071 static void __exit lego_usb_tower_exit(void)
1072 {
1073         dbg(2, "%s: enter", __FUNCTION__);
1074
1075         /* deregister this driver with the USB subsystem */
1076         usb_deregister (&tower_driver);
1077
1078         dbg(2, "%s: leave", __FUNCTION__);
1079 }
1080
1081 module_init (lego_usb_tower_init);
1082 module_exit (lego_usb_tower_exit);
1083
1084 MODULE_AUTHOR(DRIVER_AUTHOR);
1085 MODULE_DESCRIPTION(DRIVER_DESC);
1086 #ifdef MODULE_LICENSE
1087 MODULE_LICENSE("GPL");
1088 #endif