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 the driver core
 275  */
 276 static struct usb_class_driver tower_class = {
 277         .name =         "legousbtower%d",
 278         .fops =         &tower_fops,
 279         .minor_base =   LEGO_USB_TOWER_MINOR_BASE,
 280 };
 281
 282
 283 /* usb specific object needed to register this driver with the usb subsystem */
 284 static struct usb_driver tower_driver = {
 285         .name =         "legousbtower",
 286         .probe =        tower_probe,
 287         .disconnect =   tower_disconnect,
 288         .id_table =     tower_table,
 289 };
 290
 291
 292 /**
 293  *      lego_usb_tower_debug_data
 294  */
 295 static inline void lego_usb_tower_debug_data (int level, const char *function, int size, const unsigned char *data)
 296 {
 297         int i;
 298
 299         if (debug < level)
 300                 return;
 301
 302         printk (KERN_DEBUG __FILE__": %s - length = %d, data = ", function, size);
 303         for (i = 0; i < size; ++i) {
 304                 printk ("%.2x ", data[i]);
 305         }
 306         printk ("\n");
 307 }
 308
 309
 310 /**
 311  *      tower_delete
 312  */
 313 static inline void tower_delete (struct lego_usb_tower *dev)
 314 {
 315         dbg(2, "%s: enter", __FUNCTION__);
 316
 317         tower_abort_transfers (dev);
 318
 319         /* free data structures */
 320         if (dev->interrupt_in_urb != NULL) {
 321                 usb_free_urb (dev->interrupt_in_urb);
 322         }
 323         if (dev->interrupt_out_urb != NULL) {
 324                 usb_free_urb (dev->interrupt_out_urb);
 325         }
 326         kfree (dev->read_buffer);
 327         kfree (dev->interrupt_in_buffer);
 328         kfree (dev->interrupt_out_buffer);
 329         kfree (dev);
 330
 331         dbg(2, "%s: leave", __FUNCTION__);
 332 }
 333
 334
 335 /**
 336  *      tower_open
 337  */
 338 static int tower_open (struct inode *inode, struct file *file)
 339 {
 340         struct lego_usb_tower *dev = NULL;
 341         int subminor;
 342         int retval = 0;
 343         struct usb_interface *interface;
 344         struct tower_reset_reply reset_reply;
 345         int result;
 346
 347         dbg(2, "%s: enter", __FUNCTION__);
 348
 349         nonseekable_open(inode, file);
 350         subminor = iminor(inode);
 351
 352         down (&disconnect_sem);
 353
 354         interface = usb_find_interface (&tower_driver, subminor);
 355
 356         if (!interface) {
 357                 err ("%s - error, can't find device for minor %d",
 358                      __FUNCTION__, subminor);
 359                 retval = -ENODEV;
 360                 goto unlock_disconnect_exit;
 361         }
 362
 363         dev = usb_get_intfdata(interface);
 364
 365         if (!dev) {
 366                 retval = -ENODEV;
 367                 goto unlock_disconnect_exit;
 368         }
 369
 370         /* lock this device */
 371         if (down_interruptible (&dev->sem)) {
 372                 retval = -ERESTARTSYS;
 373                 goto unlock_disconnect_exit;
 374         }
 375
 376         /* allow opening only once */
 377         if (dev->open_count) {
 378                 retval = -EBUSY;
 379                 goto unlock_exit;
 380         }
 381         dev->open_count = 1;
 382
 383         /* reset the tower */
 384         result = usb_control_msg (dev->udev,
 385                                   usb_rcvctrlpipe(dev->udev, 0),
 386                                   LEGO_USB_TOWER_REQUEST_RESET,
 387                                   USB_TYPE_VENDOR | USB_DIR_IN | USB_RECIP_DEVICE,
 388                                   0,
 389                                   0,
 390                                   &reset_reply,
 391                                   sizeof(reset_reply),
 392                                   1000);
 393         if (result < 0) {
 394                 err("LEGO USB Tower reset control request failed");
 395                 retval = result;
 396                 goto unlock_exit;
 397         }
 398
 399         /* initialize in direction */
 400         dev->read_buffer_length = 0;
 401         dev->read_packet_length = 0;
 402         usb_fill_int_urb (dev->interrupt_in_urb,
 403                           dev->udev,
 404                           usb_rcvintpipe(dev->udev, dev->interrupt_in_endpoint->bEndpointAddress),
 405                           dev->interrupt_in_buffer,
 406                           le16_to_cpu(dev->interrupt_in_endpoint->wMaxPacketSize),
 407                           tower_interrupt_in_callback,
 408                           dev,
 409                           dev->interrupt_in_interval);
 410
 411         dev->interrupt_in_running = 1;
 412         dev->interrupt_in_done = 0;
 413         mb();
 414
 415         retval = usb_submit_urb (dev->interrupt_in_urb, GFP_KERNEL);
 416         if (retval) {
 417                 err("Couldn't submit interrupt_in_urb %d", retval);
 418                 dev->interrupt_in_running = 0;
 419                 dev->open_count = 0;
 420                 goto unlock_exit;
 421         }
 422
 423         /* save device in the file's private structure */
 424         file->private_data = dev;
 425
 426 unlock_exit:
 427         up (&dev->sem);
 428
 429 unlock_disconnect_exit:
 430         up (&disconnect_sem);
 431
 432         dbg(2, "%s: leave, return value %d ", __FUNCTION__, retval);
 433
 434         return retval;
 435 }
 436
 437 /**
 438  *      tower_release
 439  */
 440 static int tower_release (struct inode *inode, struct file *file)
 441 {
 442         struct lego_usb_tower *dev;
 443         int retval = 0;
 444
 445         dbg(2, "%s: enter", __FUNCTION__);
 446
 447         dev = (struct lego_usb_tower *)file->private_data;
 448
 449         if (dev == NULL) {
 450                 dbg(1, "%s: object is NULL", __FUNCTION__);
 451                 retval = -ENODEV;
 452                 goto exit;
 453         }
 454
 455         if (down_interruptible (&dev->sem)) {
 456                 retval = -ERESTARTSYS;
 457                 goto exit;
 458         }
 459
 460         if (dev->open_count != 1) {
 461                 dbg(1, "%s: device not opened exactly once", __FUNCTION__);
 462                 retval = -ENODEV;
 463                 goto unlock_exit;
 464         }
 465         if (dev->udev == NULL) {
 466                 /* the device was unplugged before the file was released */
 467                 up (&dev->sem); /* unlock here as tower_delete frees dev */
 468                 tower_delete (dev);
 469                 goto exit;
 470         }
 471
 472         /* wait until write transfer is finished */
 473         if (dev->interrupt_out_busy) {
 474                 wait_event_interruptible_timeout (dev->write_wait, !dev->interrupt_out_busy, 2 * HZ);
 475         }
 476         tower_abort_transfers (dev);
 477         dev->open_count = 0;
 478
 479 unlock_exit:
 480         up (&dev->sem);
 481
 482 exit:
 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->interrupt_in_urb != NULL && dev->udev) {
 506                         usb_kill_urb (dev->interrupt_in_urb);
 507                 }
 508         }
 509         if (dev->interrupt_out_busy) {
 510                 if (dev->interrupt_out_urb != NULL && dev->udev) {
 511                         usb_kill_urb (dev->interrupt_out_urb);
 512                 }
 513         }
 514
 515 exit:
 516         dbg(2, "%s: leave", __FUNCTION__);
 517 }
 518
 519
 520 /**
 521  *      tower_check_for_read_packet
 522  *
 523  *      To get correct semantics for signals and non-blocking I/O
 524  *      with packetizing we pretend not to see any data in the read buffer
 525  *      until it has been there unchanged for at least
 526  *      dev->packet_timeout_jiffies, or until the buffer is full.
 527  */
 528 static void tower_check_for_read_packet (struct lego_usb_tower *dev)
 529 {
 530         spin_lock_irq (&dev->read_buffer_lock);
 531         if (!packet_timeout
 532             || time_after(jiffies, dev->read_last_arrival + dev->packet_timeout_jiffies)
 533             || dev->read_buffer_length == read_buffer_size) {
 534                 dev->read_packet_length = dev->read_buffer_length;
 535         }
 536         dev->interrupt_in_done = 0;
 537         spin_unlock_irq (&dev->read_buffer_lock);
 538 }
 539
 540
 541 /**
 542  *      tower_poll
 543  */
 544 static unsigned int tower_poll (struct file *file, poll_table *wait)
 545 {
 546         struct lego_usb_tower *dev;
 547         unsigned int mask = 0;
 548
 549         dbg(2, "%s: enter", __FUNCTION__);
 550
 551         dev = file->private_data;
 552
 553         poll_wait(file, &dev->read_wait, wait);
 554         poll_wait(file, &dev->write_wait, wait);
 555
 556         tower_check_for_read_packet(dev);
 557         if (dev->read_packet_length > 0) {
 558                 mask |= POLLIN | POLLRDNORM;
 559         }
 560         if (!dev->interrupt_out_busy) {
 561                 mask |= POLLOUT | POLLWRNORM;
 562         }
 563
 564         dbg(2, "%s: leave, mask = %d", __FUNCTION__, mask);
 565
 566         return mask;
 567 }
 568
 569
 570 /**
 571  *      tower_llseek
 572  */
 573 static loff_t tower_llseek (struct file *file, loff_t off, int whence)
 574 {
 575         return -ESPIPE;         /* unseekable */
 576 }
 577
 578
 579 /**
 580  *      tower_read
 581  */
 582 static ssize_t tower_read (struct file *file, char __user *buffer, size_t count, loff_t *ppos)
 583 {
 584         struct lego_usb_tower *dev;
 585         size_t bytes_to_read;
 586         int i;
 587         int retval = 0;
 588         unsigned long timeout = 0;
 589
 590         dbg(2, "%s: enter, count = %Zd", __FUNCTION__, count);
 591
 592         dev = (struct lego_usb_tower *)file->private_data;
 593
 594         /* lock this object */
 595         if (down_interruptible (&dev->sem)) {
 596                 retval = -ERESTARTSYS;
 597                 goto exit;
 598         }
 599
 600         /* verify that the device wasn't unplugged */
 601         if (dev->udev == NULL) {
 602                 retval = -ENODEV;
 603                 err("No device or device unplugged %d", retval);
 604                 goto unlock_exit;
 605         }
 606
 607         /* verify that we actually have some data to read */
 608         if (count == 0) {
 609                 dbg(1, "%s: read request of 0 bytes", __FUNCTION__);
 610                 goto unlock_exit;
 611         }
 612
 613         if (read_timeout) {
 614                 timeout = jiffies + read_timeout * HZ / 1000;
 615         }
 616
 617         /* wait for data */
 618         tower_check_for_read_packet (dev);
 619         while (dev->read_packet_length == 0) {
 620                 if (file->f_flags & O_NONBLOCK) {
 621                         retval = -EAGAIN;
 622                         goto unlock_exit;
 623                 }
 624                 retval = wait_event_interruptible_timeout(dev->read_wait, dev->interrupt_in_done, dev->packet_timeout_jiffies);
 625                 if (retval < 0) {
 626                         goto unlock_exit;
 627                 }
 628
 629                 /* reset read timeout during read or write activity */
 630                 if (read_timeout
 631                     && (dev->read_buffer_length || dev->interrupt_out_busy)) {
 632                         timeout = jiffies + read_timeout * HZ / 1000;
 633                 }
 634                 /* check for read timeout */
 635                 if (read_timeout && time_after (jiffies, timeout)) {
 636                         retval = -ETIMEDOUT;
 637                         goto unlock_exit;
 638                 }
 639                 tower_check_for_read_packet (dev);
 640         }
 641
 642         /* copy the data from read_buffer into userspace */
 643         bytes_to_read = min(count, dev->read_packet_length);
 644
 645         if (copy_to_user (buffer, dev->read_buffer, bytes_to_read)) {
 646                 retval = -EFAULT;
 647                 goto unlock_exit;
 648         }
 649
 650         spin_lock_irq (&dev->read_buffer_lock);
 651         dev->read_buffer_length -= bytes_to_read;
 652         dev->read_packet_length -= bytes_to_read;
 653         for (i=0; i<dev->read_buffer_length; i++) {
 654                 dev->read_buffer[i] = dev->read_buffer[i+bytes_to_read];
 655         }
 656         spin_unlock_irq (&dev->read_buffer_lock);
 657
 658         retval = bytes_to_read;
 659
 660 unlock_exit:
 661         /* unlock the device */
 662         up (&dev->sem);
 663
 664 exit:
 665         dbg(2, "%s: leave, return value %d", __FUNCTION__, retval);
 666         return retval;
 667 }
 668
 669
 670 /**
 671  *      tower_write
 672  */
 673 static ssize_t tower_write (struct file *file, const char __user *buffer, size_t count, loff_t *ppos)
 674 {
 675         struct lego_usb_tower *dev;
 676         size_t bytes_to_write;
 677         int retval = 0;
 678
 679         dbg(2, "%s: enter, count = %Zd", __FUNCTION__, count);
 680
 681         dev = (struct lego_usb_tower *)file->private_data;
 682
 683         /* lock this object */
 684         if (down_interruptible (&dev->sem)) {
 685                 retval = -ERESTARTSYS;
 686                 goto exit;
 687         }
 688
 689         /* verify that the device wasn't unplugged */
 690         if (dev->udev == NULL) {
 691                 retval = -ENODEV;
 692                 err("No device or device unplugged %d", retval);
 693                 goto unlock_exit;
 694         }
 695
 696         /* verify that we actually have some data to write */
 697         if (count == 0) {
 698                 dbg(1, "%s: write request of 0 bytes", __FUNCTION__);
 699                 goto unlock_exit;
 700         }
 701
 702         /* wait until previous transfer is finished */
 703         while (dev->interrupt_out_busy) {
 704                 if (file->f_flags & O_NONBLOCK) {
 705                         retval = -EAGAIN;
 706                         goto unlock_exit;
 707                 }
 708                 retval = wait_event_interruptible (dev->write_wait, !dev->interrupt_out_busy);
 709                 if (retval) {
 710                         goto unlock_exit;
 711                 }
 712         }
 713
 714         /* write the data into interrupt_out_buffer from userspace */
 715         bytes_to_write = min_t(int, count, write_buffer_size);
 716         dbg(4, "%s: count = %Zd, bytes_to_write = %Zd", __FUNCTION__, count, bytes_to_write);
 717
 718         if (copy_from_user (dev->interrupt_out_buffer, buffer, bytes_to_write)) {
 719                 retval = -EFAULT;
 720                 goto unlock_exit;
 721         }
 722
 723         /* send off the urb */
 724         usb_fill_int_urb(dev->interrupt_out_urb,
 725                          dev->udev,
 726                          usb_sndintpipe(dev->udev, dev->interrupt_out_endpoint->bEndpointAddress),
 727                          dev->interrupt_out_buffer,
 728                          bytes_to_write,
 729                          tower_interrupt_out_callback,
 730                          dev,
 731                          dev->interrupt_out_interval);
 732
 733         dev->interrupt_out_busy = 1;
 734         wmb();
 735
 736         retval = usb_submit_urb (dev->interrupt_out_urb, GFP_KERNEL);
 737         if (retval) {
 738                 dev->interrupt_out_busy = 0;
 739                 err("Couldn't submit interrupt_out_urb %d", retval);
 740                 goto unlock_exit;
 741         }
 742         retval = bytes_to_write;
 743
 744 unlock_exit:
 745         /* unlock the device */
 746         up (&dev->sem);
 747
 748 exit:
 749         dbg(2, "%s: leave, return value %d", __FUNCTION__, retval);
 750
 751         return retval;
 752 }
 753
 754
 755 /**
 756  *      tower_interrupt_in_callback
 757  */
 758 static void tower_interrupt_in_callback (struct urb *urb, struct pt_regs *regs)
 759 {
 760         struct lego_usb_tower *dev = (struct lego_usb_tower *)urb->context;
 761         int retval;
 762
 763         dbg(4, "%s: enter, status %d", __FUNCTION__, urb->status);
 764
 765         lego_usb_tower_debug_data(5, __FUNCTION__, urb->actual_length, urb->transfer_buffer);
 766
 767         if (urb->status) {
 768                 if (urb->status == -ENOENT ||
 769                     urb->status == -ECONNRESET ||
 770                     urb->status == -ESHUTDOWN) {
 771                         goto exit;
 772                 } else {
 773                         dbg(1, "%s: nonzero status received: %d", __FUNCTION__, urb->status);
 774                         goto resubmit; /* maybe we can recover */
 775                 }
 776         }
 777
 778         if (urb->actual_length > 0) {
 779                 spin_lock (&dev->read_buffer_lock);
 780                 if (dev->read_buffer_length + urb->actual_length < read_buffer_size) {
 781                         memcpy (dev->read_buffer + dev->read_buffer_length,
 782                                 dev->interrupt_in_buffer,
 783                                 urb->actual_length);
 784                         dev->read_buffer_length += urb->actual_length;
 785                         dev->read_last_arrival = jiffies;
 786                         dbg(3, "%s: received %d bytes", __FUNCTION__, urb->actual_length);
 787                 } else {
 788                         printk(KERN_WARNING "%s: read_buffer overflow, %d bytes dropped", __FUNCTION__, urb->actual_length);
 789                 }
 790                 spin_unlock (&dev->read_buffer_lock);
 791         }
 792
 793 resubmit:
 794         /* resubmit if we're still running */
 795         if (dev->interrupt_in_running && dev->udev) {
 796                 retval = usb_submit_urb (dev->interrupt_in_urb, GFP_ATOMIC);
 797                 if (retval) {
 798                         err("%s: usb_submit_urb failed (%d)", __FUNCTION__, retval);
 799                 }
 800         }
 801
 802 exit:
 803         dev->interrupt_in_done = 1;
 804         wake_up_interruptible (&dev->read_wait);
 805
 806         lego_usb_tower_debug_data(5, __FUNCTION__, urb->actual_length, urb->transfer_buffer);
 807         dbg(4, "%s: leave, status %d", __FUNCTION__, urb->status);
 808 }
 809
 810
 811 /**
 812  *      tower_interrupt_out_callback
 813  */
 814 static void tower_interrupt_out_callback (struct urb *urb, struct pt_regs *regs)
 815 {
 816         struct lego_usb_tower *dev = (struct lego_usb_tower *)urb->context;
 817
 818         dbg(4, "%s: enter, status %d", __FUNCTION__, urb->status);
 819         lego_usb_tower_debug_data(5, __FUNCTION__, urb->actual_length, urb->transfer_buffer);
 820
 821         /* sync/async unlink faults aren't errors */
 822         if (urb->status && !(urb->status == -ENOENT ||
 823                              urb->status == -ECONNRESET ||
 824                              urb->status == -ESHUTDOWN)) {
 825                 dbg(1, "%s - nonzero write bulk status received: %d",
 826                     __FUNCTION__, urb->status);
 827         }
 828
 829         dev->interrupt_out_busy = 0;
 830         wake_up_interruptible(&dev->write_wait);
 831
 832         lego_usb_tower_debug_data(5, __FUNCTION__, urb->actual_length, urb->transfer_buffer);
 833         dbg(4, "%s: leave, status %d", __FUNCTION__, urb->status);
 834 }
 835
 836
 837 /**
 838  *      tower_probe
 839  *
 840  *      Called by the usb core when a new device is connected that it thinks
 841  *      this driver might be interested in.
 842  */
 843 static int tower_probe (struct usb_interface *interface, const struct usb_device_id *id)
 844 {
 845         struct usb_device *udev = interface_to_usbdev(interface);
 846         struct lego_usb_tower *dev = NULL;
 847         struct usb_host_interface *iface_desc;
 848         struct usb_endpoint_descriptor* endpoint;
 849         struct tower_get_version_reply get_version_reply;
 850         int i;
 851         int retval = -ENOMEM;
 852         int result;
 853
 854         dbg(2, "%s: enter", __FUNCTION__);
 855
 856         if (udev == NULL) {
 857                 info ("udev is NULL.");
 858         }
 859
 860         /* allocate memory for our device state and initialize it */
 861
 862         dev = kmalloc (sizeof(struct lego_usb_tower), GFP_KERNEL);
 863
 864         if (dev == NULL) {
 865                 err ("Out of memory");
 866                 goto exit;
 867         }
 868
 869         init_MUTEX (&dev->sem);
 870
 871         dev->udev = udev;
 872         dev->open_count = 0;
 873
 874         dev->read_buffer = NULL;
 875         dev->read_buffer_length = 0;
 876         dev->read_packet_length = 0;
 877         spin_lock_init (&dev->read_buffer_lock);
 878         dev->packet_timeout_jiffies = packet_timeout * HZ / 1000;
 879         dev->read_last_arrival = jiffies;
 880
 881         init_waitqueue_head (&dev->read_wait);
 882         init_waitqueue_head (&dev->write_wait);
 883
 884         dev->interrupt_in_buffer = NULL;
 885         dev->interrupt_in_endpoint = NULL;
 886         dev->interrupt_in_urb = NULL;
 887         dev->interrupt_in_running = 0;
 888         dev->interrupt_in_done = 0;
 889
 890         dev->interrupt_out_buffer = NULL;
 891         dev->interrupt_out_endpoint = NULL;
 892         dev->interrupt_out_urb = NULL;
 893         dev->interrupt_out_busy = 0;
 894
 895         iface_desc = interface->cur_altsetting;
 896
 897         /* set up the endpoint information */
 898         for (i = 0; i < iface_desc->desc.bNumEndpoints; ++i) {
 899                 endpoint = &iface_desc->endpoint[i].desc;
 900
 901                 if (((endpoint->bEndpointAddress & USB_ENDPOINT_DIR_MASK) == USB_DIR_IN) &&
 902                     ((endpoint->bmAttributes & USB_ENDPOINT_XFERTYPE_MASK) == USB_ENDPOINT_XFER_INT)) {
 903                         dev->interrupt_in_endpoint = endpoint;
 904                 }
 905
 906                 if (((endpoint->bEndpointAddress & USB_ENDPOINT_DIR_MASK) == USB_DIR_OUT) &&
 907                     ((endpoint->bmAttributes & USB_ENDPOINT_XFERTYPE_MASK) == USB_ENDPOINT_XFER_INT)) {
 908                         dev->interrupt_out_endpoint = endpoint;
 909                 }
 910         }
 911         if(dev->interrupt_in_endpoint == NULL) {
 912                 err("interrupt in endpoint not found");
 913                 goto error;
 914         }
 915         if (dev->interrupt_out_endpoint == NULL) {
 916                 err("interrupt out endpoint not found");
 917                 goto error;
 918         }
 919
 920         dev->read_buffer = kmalloc (read_buffer_size, GFP_KERNEL);
 921         if (!dev->read_buffer) {
 922                 err("Couldn't allocate read_buffer");
 923                 goto error;
 924         }
 925         dev->interrupt_in_buffer = kmalloc (le16_to_cpu(dev->interrupt_in_endpoint->wMaxPacketSize), GFP_KERNEL);
 926         if (!dev->interrupt_in_buffer) {
 927                 err("Couldn't allocate interrupt_in_buffer");
 928                 goto error;
 929         }
 930         dev->interrupt_in_urb = usb_alloc_urb(0, GFP_KERNEL);
 931         if (!dev->interrupt_in_urb) {
 932                 err("Couldn't allocate interrupt_in_urb");
 933                 goto error;
 934         }
 935         dev->interrupt_out_buffer = kmalloc (write_buffer_size, GFP_KERNEL);
 936         if (!dev->interrupt_out_buffer) {
 937                 err("Couldn't allocate interrupt_out_buffer");
 938                 goto error;
 939         }
 940         dev->interrupt_out_urb = usb_alloc_urb(0, GFP_KERNEL);
 941         if (!dev->interrupt_out_urb) {
 942                 err("Couldn't allocate interrupt_out_urb");
 943                 goto error;
 944         }
 945         dev->interrupt_in_interval = interrupt_in_interval ? interrupt_in_interval : dev->interrupt_in_endpoint->bInterval;
 946         dev->interrupt_out_interval = interrupt_out_interval ? interrupt_out_interval : dev->interrupt_out_endpoint->bInterval;
 947
 948         /* we can register the device now, as it is ready */
 949         usb_set_intfdata (interface, dev);
 950
 951         retval = usb_register_dev (interface, &tower_class);
 952
 953         if (retval) {
 954                 /* something prevented us from registering this driver */
 955                 err ("Not able to get a minor for this device.");
 956                 usb_set_intfdata (interface, NULL);
 957                 goto error;
 958         }
 959         dev->minor = interface->minor;
 960
 961         /* let the user know what node this device is now attached to */
 962         info ("LEGO USB Tower #%d now attached to major %d minor %d", (dev->minor - LEGO_USB_TOWER_MINOR_BASE), USB_MAJOR, dev->minor);
 963
 964         /* get the firmware version and log it */
 965         result = usb_control_msg (udev,
 966                                   usb_rcvctrlpipe(udev, 0),
 967                                   LEGO_USB_TOWER_REQUEST_GET_VERSION,
 968                                   USB_TYPE_VENDOR | USB_DIR_IN | USB_RECIP_DEVICE,
 969                                   0,
 970                                   0,
 971                                   &get_version_reply,
 972                                   sizeof(get_version_reply),
 973                                   1000);
 974         if (result < 0) {
 975                 err("LEGO USB Tower get version control request failed");
 976                 retval = result;
 977                 goto error;
 978         }
 979         info("LEGO USB Tower firmware version is %d.%d build %d",
 980              get_version_reply.major,
 981              get_version_reply.minor,
 982              le16_to_cpu(get_version_reply.build_no));
 983
 984
 985 exit:
 986         dbg(2, "%s: leave, return value 0x%.8lx (dev)", __FUNCTION__, (long) dev);
 987
 988         return retval;
 989
 990 error:
 991         tower_delete(dev);
 992         return retval;
 993 }
 994
 995
 996 /**
 997  *      tower_disconnect
 998  *
 999  *      Called by the usb core when the device is removed from the system.
1000  */
1001 static void tower_disconnect (struct usb_interface *interface)
1002 {
1003         struct lego_usb_tower *dev;
1004         int minor;
1005
1006         dbg(2, "%s: enter", __FUNCTION__);
1007
1008         down (&disconnect_sem);
1009
1010         dev = usb_get_intfdata (interface);
1011         usb_set_intfdata (interface, NULL);
1012
1013
1014         down (&dev->sem);
1015
1016         minor = dev->minor;
1017
1018         /* give back our minor */
1019         usb_deregister_dev (interface, &tower_class);
1020
1021         /* if the device is not opened, then we clean up right now */
1022         if (!dev->open_count) {
1023                 up (&dev->sem);
1024                 tower_delete (dev);
1025         } else {
1026                 dev->udev = NULL;
1027                 up (&dev->sem);
1028         }
1029
1030         up (&disconnect_sem);
1031
1032         info("LEGO USB Tower #%d now disconnected", (minor - LEGO_USB_TOWER_MINOR_BASE));
1033
1034         dbg(2, "%s: leave", __FUNCTION__);
1035 }
1036
1037
1038
1039 /**
1040  *      lego_usb_tower_init
1041  */
1042 static int __init lego_usb_tower_init(void)
1043 {
1044         int result;
1045         int retval = 0;
1046
1047         dbg(2, "%s: enter", __FUNCTION__);
1048
1049         /* register this driver with the USB subsystem */
1050         result = usb_register(&tower_driver);
1051         if (result < 0) {
1052                 err("usb_register failed for the "__FILE__" driver. Error number %d", result);
1053                 retval = -1;
1054                 goto exit;
1055         }
1056
1057         info(DRIVER_DESC " " DRIVER_VERSION);
1058
1059 exit:
1060         dbg(2, "%s: leave, return value %d", __FUNCTION__, retval);
1061
1062         return retval;
1063 }
1064
1065
1066 /**
1067  *      lego_usb_tower_exit
1068  */
1069 static void __exit lego_usb_tower_exit(void)
1070 {
1071         dbg(2, "%s: enter", __FUNCTION__);
1072
1073         /* deregister this driver with the USB subsystem */
1074         usb_deregister (&tower_driver);
1075
1076         dbg(2, "%s: leave", __FUNCTION__);
1077 }
1078
1079 module_init (lego_usb_tower_init);
1080 module_exit (lego_usb_tower_exit);
1081
1082 MODULE_AUTHOR(DRIVER_AUTHOR);
1083 MODULE_DESCRIPTION(DRIVER_DESC);
1084 #ifdef MODULE_LICENSE
1085 MODULE_LICENSE("GPL");
1086 #endif