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/smp_lock.h>
  84 #include <linux/completion.h>
  85 #include <linux/mutex.h>
  86 #include <asm/uaccess.h>
  87 #include <linux/usb.h>
  88 #include <linux/poll.h>
  89
  90
  91 #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);
 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 /* prevent races between open() and disconnect */
 259 static DEFINE_MUTEX (disconnect_mutex);
 260
 261 /* file operations needed when we register this driver */
 262 static const 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         usb_free_urb(dev->interrupt_in_urb);
 321         usb_free_urb(dev->interrupt_out_urb);
 322         kfree (dev->read_buffer);
 323         kfree (dev->interrupt_in_buffer);
 324         kfree (dev->interrupt_out_buffer);
 325         kfree (dev);
 326
 327         dbg(2, "%s: leave", __FUNCTION__);
 328 }
 329
 330
 331 /**
 332  *      tower_open
 333  */
 334 static int tower_open (struct inode *inode, struct file *file)
 335 {
 336         struct lego_usb_tower *dev = NULL;
 337         int subminor;
 338         int retval = 0;
 339         struct usb_interface *interface;
 340         struct tower_reset_reply reset_reply;
 341         int result;
 342
 343         dbg(2, "%s: enter", __FUNCTION__);
 344
 345         nonseekable_open(inode, file);
 346         subminor = iminor(inode);
 347
 348         mutex_lock (&disconnect_mutex);
 349
 350         interface = usb_find_interface (&tower_driver, subminor);
 351
 352         if (!interface) {
 353                 err ("%s - error, can't find device for minor %d",
 354                      __FUNCTION__, subminor);
 355                 retval = -ENODEV;
 356                 goto unlock_disconnect_exit;
 357         }
 358
 359         dev = usb_get_intfdata(interface);
 360
 361         if (!dev) {
 362                 retval = -ENODEV;
 363                 goto unlock_disconnect_exit;
 364         }
 365
 366         /* lock this device */
 367         if (down_interruptible (&dev->sem)) {
 368                 retval = -ERESTARTSYS;
 369                 goto unlock_disconnect_exit;
 370         }
 371
 372         /* allow opening only once */
 373         if (dev->open_count) {
 374                 retval = -EBUSY;
 375                 goto unlock_exit;
 376         }
 377         dev->open_count = 1;
 378
 379         /* reset the tower */
 380         result = usb_control_msg (dev->udev,
 381                                   usb_rcvctrlpipe(dev->udev, 0),
 382                                   LEGO_USB_TOWER_REQUEST_RESET,
 383                                   USB_TYPE_VENDOR | USB_DIR_IN | USB_RECIP_DEVICE,
 384                                   0,
 385                                   0,
 386                                   &reset_reply,
 387                                   sizeof(reset_reply),
 388                                   1000);
 389         if (result < 0) {
 390                 err("LEGO USB Tower reset control request failed");
 391                 retval = result;
 392                 goto unlock_exit;
 393         }
 394
 395         /* initialize in direction */
 396         dev->read_buffer_length = 0;
 397         dev->read_packet_length = 0;
 398         usb_fill_int_urb (dev->interrupt_in_urb,
 399                           dev->udev,
 400                           usb_rcvintpipe(dev->udev, dev->interrupt_in_endpoint->bEndpointAddress),
 401                           dev->interrupt_in_buffer,
 402                           le16_to_cpu(dev->interrupt_in_endpoint->wMaxPacketSize),
 403                           tower_interrupt_in_callback,
 404                           dev,
 405                           dev->interrupt_in_interval);
 406
 407         dev->interrupt_in_running = 1;
 408         dev->interrupt_in_done = 0;
 409         mb();
 410
 411         retval = usb_submit_urb (dev->interrupt_in_urb, GFP_KERNEL);
 412         if (retval) {
 413                 err("Couldn't submit interrupt_in_urb %d", retval);
 414                 dev->interrupt_in_running = 0;
 415                 dev->open_count = 0;
 416                 goto unlock_exit;
 417         }
 418
 419         /* save device in the file's private structure */
 420         file->private_data = dev;
 421
 422 unlock_exit:
 423         up (&dev->sem);
 424
 425 unlock_disconnect_exit:
 426         mutex_unlock (&disconnect_mutex);
 427
 428         dbg(2, "%s: leave, return value %d ", __FUNCTION__, retval);
 429
 430         return retval;
 431 }
 432
 433 /**
 434  *      tower_release
 435  */
 436 static int tower_release (struct inode *inode, struct file *file)
 437 {
 438         struct lego_usb_tower *dev;
 439         int retval = 0;
 440
 441         dbg(2, "%s: enter", __FUNCTION__);
 442
 443         dev = (struct lego_usb_tower *)file->private_data;
 444
 445         if (dev == NULL) {
 446                 dbg(1, "%s: object is NULL", __FUNCTION__);
 447                 retval = -ENODEV;
 448                 goto exit;
 449         }
 450
 451         if (down_interruptible (&dev->sem)) {
 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                 up (&dev->sem); /* unlock here as tower_delete frees dev */
 464                 tower_delete (dev);
 465                 goto exit;
 466         }
 467
 468         /* wait until write transfer is finished */
 469         if (dev->interrupt_out_busy) {
 470                 wait_event_interruptible_timeout (dev->write_wait, !dev->interrupt_out_busy, 2 * HZ);
 471         }
 472         tower_abort_transfers (dev);
 473         dev->open_count = 0;
 474
 475 unlock_exit:
 476         up (&dev->sem);
 477
 478 exit:
 479         dbg(2, "%s: leave, return value %d", __FUNCTION__, retval);
 480         return retval;
 481 }
 482
 483
 484 /**
 485  *      tower_abort_transfers
 486  *      aborts transfers and frees associated data structures
 487  */
 488 static void tower_abort_transfers (struct lego_usb_tower *dev)
 489 {
 490         dbg(2, "%s: enter", __FUNCTION__);
 491
 492         if (dev == NULL) {
 493                 dbg(1, "%s: dev is null", __FUNCTION__);
 494                 goto exit;
 495         }
 496
 497         /* shutdown transfer */
 498         if (dev->interrupt_in_running) {
 499                 dev->interrupt_in_running = 0;
 500                 mb();
 501                 if (dev->udev)
 502                         usb_kill_urb (dev->interrupt_in_urb);
 503         }
 504         if (dev->interrupt_out_busy && dev->udev)
 505                 usb_kill_urb(dev->interrupt_out_urb);
 506
 507 exit:
 508         dbg(2, "%s: leave", __FUNCTION__);
 509 }
 510
 511
 512 /**
 513  *      tower_check_for_read_packet
 514  *
 515  *      To get correct semantics for signals and non-blocking I/O
 516  *      with packetizing we pretend not to see any data in the read buffer
 517  *      until it has been there unchanged for at least
 518  *      dev->packet_timeout_jiffies, or until the buffer is full.
 519  */
 520 static void tower_check_for_read_packet (struct lego_usb_tower *dev)
 521 {
 522         spin_lock_irq (&dev->read_buffer_lock);
 523         if (!packet_timeout
 524             || time_after(jiffies, dev->read_last_arrival + dev->packet_timeout_jiffies)
 525             || dev->read_buffer_length == read_buffer_size) {
 526                 dev->read_packet_length = dev->read_buffer_length;
 527         }
 528         dev->interrupt_in_done = 0;
 529         spin_unlock_irq (&dev->read_buffer_lock);
 530 }
 531
 532
 533 /**
 534  *      tower_poll
 535  */
 536 static unsigned int tower_poll (struct file *file, poll_table *wait)
 537 {
 538         struct lego_usb_tower *dev;
 539         unsigned int mask = 0;
 540
 541         dbg(2, "%s: enter", __FUNCTION__);
 542
 543         dev = file->private_data;
 544
 545         poll_wait(file, &dev->read_wait, wait);
 546         poll_wait(file, &dev->write_wait, wait);
 547
 548         tower_check_for_read_packet(dev);
 549         if (dev->read_packet_length > 0) {
 550                 mask |= POLLIN | POLLRDNORM;
 551         }
 552         if (!dev->interrupt_out_busy) {
 553                 mask |= POLLOUT | POLLWRNORM;
 554         }
 555
 556         dbg(2, "%s: leave, mask = %d", __FUNCTION__, mask);
 557
 558         return mask;
 559 }
 560
 561
 562 /**
 563  *      tower_llseek
 564  */
 565 static loff_t tower_llseek (struct file *file, loff_t off, int whence)
 566 {
 567         return -ESPIPE;         /* unseekable */
 568 }
 569
 570
 571 /**
 572  *      tower_read
 573  */
 574 static ssize_t tower_read (struct file *file, char __user *buffer, size_t count, loff_t *ppos)
 575 {
 576         struct lego_usb_tower *dev;
 577         size_t bytes_to_read;
 578         int i;
 579         int retval = 0;
 580         unsigned long timeout = 0;
 581
 582         dbg(2, "%s: enter, count = %Zd", __FUNCTION__, count);
 583
 584         dev = (struct lego_usb_tower *)file->private_data;
 585
 586         /* lock this object */
 587         if (down_interruptible (&dev->sem)) {
 588                 retval = -ERESTARTSYS;
 589                 goto exit;
 590         }
 591
 592         /* verify that the device wasn't unplugged */
 593         if (dev->udev == NULL) {
 594                 retval = -ENODEV;
 595                 err("No device or device unplugged %d", retval);
 596                 goto unlock_exit;
 597         }
 598
 599         /* verify that we actually have some data to read */
 600         if (count == 0) {
 601                 dbg(1, "%s: read request of 0 bytes", __FUNCTION__);
 602                 goto unlock_exit;
 603         }
 604
 605         if (read_timeout) {
 606                 timeout = jiffies + read_timeout * HZ / 1000;
 607         }
 608
 609         /* wait for data */
 610         tower_check_for_read_packet (dev);
 611         while (dev->read_packet_length == 0) {
 612                 if (file->f_flags & O_NONBLOCK) {
 613                         retval = -EAGAIN;
 614                         goto unlock_exit;
 615                 }
 616                 retval = wait_event_interruptible_timeout(dev->read_wait, dev->interrupt_in_done, dev->packet_timeout_jiffies);
 617                 if (retval < 0) {
 618                         goto unlock_exit;
 619                 }
 620
 621                 /* reset read timeout during read or write activity */
 622                 if (read_timeout
 623                     && (dev->read_buffer_length || dev->interrupt_out_busy)) {
 624                         timeout = jiffies + read_timeout * HZ / 1000;
 625                 }
 626                 /* check for read timeout */
 627                 if (read_timeout && time_after (jiffies, timeout)) {
 628                         retval = -ETIMEDOUT;
 629                         goto unlock_exit;
 630                 }
 631                 tower_check_for_read_packet (dev);
 632         }
 633
 634         /* copy the data from read_buffer into userspace */
 635         bytes_to_read = min(count, dev->read_packet_length);
 636
 637         if (copy_to_user (buffer, dev->read_buffer, bytes_to_read)) {
 638                 retval = -EFAULT;
 639                 goto unlock_exit;
 640         }
 641
 642         spin_lock_irq (&dev->read_buffer_lock);
 643         dev->read_buffer_length -= bytes_to_read;
 644         dev->read_packet_length -= bytes_to_read;
 645         for (i=0; i<dev->read_buffer_length; i++) {
 646                 dev->read_buffer[i] = dev->read_buffer[i+bytes_to_read];
 647         }
 648         spin_unlock_irq (&dev->read_buffer_lock);
 649
 650         retval = bytes_to_read;
 651
 652 unlock_exit:
 653         /* unlock the device */
 654         up (&dev->sem);
 655
 656 exit:
 657         dbg(2, "%s: leave, return value %d", __FUNCTION__, retval);
 658         return retval;
 659 }
 660
 661
 662 /**
 663  *      tower_write
 664  */
 665 static ssize_t tower_write (struct file *file, const char __user *buffer, size_t count, loff_t *ppos)
 666 {
 667         struct lego_usb_tower *dev;
 668         size_t bytes_to_write;
 669         int retval = 0;
 670
 671         dbg(2, "%s: enter, count = %Zd", __FUNCTION__, count);
 672
 673         dev = (struct lego_usb_tower *)file->private_data;
 674
 675         /* lock this object */
 676         if (down_interruptible (&dev->sem)) {
 677                 retval = -ERESTARTSYS;
 678                 goto exit;
 679         }
 680
 681         /* verify that the device wasn't unplugged */
 682         if (dev->udev == NULL) {
 683                 retval = -ENODEV;
 684                 err("No device or device unplugged %d", retval);
 685                 goto unlock_exit;
 686         }
 687
 688         /* verify that we actually have some data to write */
 689         if (count == 0) {
 690                 dbg(1, "%s: write request of 0 bytes", __FUNCTION__);
 691                 goto unlock_exit;
 692         }
 693
 694         /* wait until previous transfer is finished */
 695         while (dev->interrupt_out_busy) {
 696                 if (file->f_flags & O_NONBLOCK) {
 697                         retval = -EAGAIN;
 698                         goto unlock_exit;
 699                 }
 700                 retval = wait_event_interruptible (dev->write_wait, !dev->interrupt_out_busy);
 701                 if (retval) {
 702                         goto unlock_exit;
 703                 }
 704         }
 705
 706         /* write the data into interrupt_out_buffer from userspace */
 707         bytes_to_write = min_t(int, count, write_buffer_size);
 708         dbg(4, "%s: count = %Zd, bytes_to_write = %Zd", __FUNCTION__, count, bytes_to_write);
 709
 710         if (copy_from_user (dev->interrupt_out_buffer, buffer, bytes_to_write)) {
 711                 retval = -EFAULT;
 712                 goto unlock_exit;
 713         }
 714
 715         /* send off the urb */
 716         usb_fill_int_urb(dev->interrupt_out_urb,
 717                          dev->udev,
 718                          usb_sndintpipe(dev->udev, dev->interrupt_out_endpoint->bEndpointAddress),
 719                          dev->interrupt_out_buffer,
 720                          bytes_to_write,
 721                          tower_interrupt_out_callback,
 722                          dev,
 723                          dev->interrupt_out_interval);
 724
 725         dev->interrupt_out_busy = 1;
 726         wmb();
 727
 728         retval = usb_submit_urb (dev->interrupt_out_urb, GFP_KERNEL);
 729         if (retval) {
 730                 dev->interrupt_out_busy = 0;
 731                 err("Couldn't submit interrupt_out_urb %d", retval);
 732                 goto unlock_exit;
 733         }
 734         retval = bytes_to_write;
 735
 736 unlock_exit:
 737         /* unlock the device */
 738         up (&dev->sem);
 739
 740 exit:
 741         dbg(2, "%s: leave, return value %d", __FUNCTION__, retval);
 742
 743         return retval;
 744 }
 745
 746
 747 /**
 748  *      tower_interrupt_in_callback
 749  */
 750 static void tower_interrupt_in_callback (struct urb *urb)
 751 {
 752         struct lego_usb_tower *dev = (struct lego_usb_tower *)urb->context;
 753         int retval;
 754
 755         dbg(4, "%s: enter, status %d", __FUNCTION__, urb->status);
 756
 757         lego_usb_tower_debug_data(5, __FUNCTION__, urb->actual_length, urb->transfer_buffer);
 758
 759         if (urb->status) {
 760                 if (urb->status == -ENOENT ||
 761                     urb->status == -ECONNRESET ||
 762                     urb->status == -ESHUTDOWN) {
 763                         goto exit;
 764                 } else {
 765                         dbg(1, "%s: nonzero status received: %d", __FUNCTION__, urb->status);
 766                         goto resubmit; /* maybe we can recover */
 767                 }
 768         }
 769
 770         if (urb->actual_length > 0) {
 771                 spin_lock (&dev->read_buffer_lock);
 772                 if (dev->read_buffer_length + urb->actual_length < read_buffer_size) {
 773                         memcpy (dev->read_buffer + dev->read_buffer_length,
 774                                 dev->interrupt_in_buffer,
 775                                 urb->actual_length);
 776                         dev->read_buffer_length += urb->actual_length;
 777                         dev->read_last_arrival = jiffies;
 778                         dbg(3, "%s: received %d bytes", __FUNCTION__, urb->actual_length);
 779                 } else {
 780                         printk(KERN_WARNING "%s: read_buffer overflow, %d bytes dropped", __FUNCTION__, urb->actual_length);
 781                 }
 782                 spin_unlock (&dev->read_buffer_lock);
 783         }
 784
 785 resubmit:
 786         /* resubmit if we're still running */
 787         if (dev->interrupt_in_running && dev->udev) {
 788                 retval = usb_submit_urb (dev->interrupt_in_urb, GFP_ATOMIC);
 789                 if (retval) {
 790                         err("%s: usb_submit_urb failed (%d)", __FUNCTION__, retval);
 791                 }
 792         }
 793
 794 exit:
 795         dev->interrupt_in_done = 1;
 796         wake_up_interruptible (&dev->read_wait);
 797
 798         lego_usb_tower_debug_data(5, __FUNCTION__, urb->actual_length, urb->transfer_buffer);
 799         dbg(4, "%s: leave, status %d", __FUNCTION__, urb->status);
 800 }
 801
 802
 803 /**
 804  *      tower_interrupt_out_callback
 805  */
 806 static void tower_interrupt_out_callback (struct urb *urb)
 807 {
 808         struct lego_usb_tower *dev = (struct lego_usb_tower *)urb->context;
 809
 810         dbg(4, "%s: enter, status %d", __FUNCTION__, urb->status);
 811         lego_usb_tower_debug_data(5, __FUNCTION__, urb->actual_length, urb->transfer_buffer);
 812
 813         /* sync/async unlink faults aren't errors */
 814         if (urb->status && !(urb->status == -ENOENT ||
 815                              urb->status == -ECONNRESET ||
 816                              urb->status == -ESHUTDOWN)) {
 817                 dbg(1, "%s - nonzero write bulk status received: %d",
 818                     __FUNCTION__, urb->status);
 819         }
 820
 821         dev->interrupt_out_busy = 0;
 822         wake_up_interruptible(&dev->write_wait);
 823
 824         lego_usb_tower_debug_data(5, __FUNCTION__, urb->actual_length, urb->transfer_buffer);
 825         dbg(4, "%s: leave, status %d", __FUNCTION__, urb->status);
 826 }
 827
 828
 829 /**
 830  *      tower_probe
 831  *
 832  *      Called by the usb core when a new device is connected that it thinks
 833  *      this driver might be interested in.
 834  */
 835 static int tower_probe (struct usb_interface *interface, const struct usb_device_id *id)
 836 {
 837         struct usb_device *udev = interface_to_usbdev(interface);
 838         struct lego_usb_tower *dev = NULL;
 839         struct usb_host_interface *iface_desc;
 840         struct usb_endpoint_descriptor* endpoint;
 841         struct tower_get_version_reply get_version_reply;
 842         int i;
 843         int retval = -ENOMEM;
 844         int result;
 845
 846         dbg(2, "%s: enter", __FUNCTION__);
 847
 848         if (udev == NULL) {
 849                 info ("udev is NULL.");
 850         }
 851
 852         /* allocate memory for our device state and initialize it */
 853
 854         dev = kmalloc (sizeof(struct lego_usb_tower), GFP_KERNEL);
 855
 856         if (dev == NULL) {
 857                 err ("Out of memory");
 858                 goto exit;
 859         }
 860
 861         init_MUTEX (&dev->sem);
 862
 863         dev->udev = udev;
 864         dev->open_count = 0;
 865
 866         dev->read_buffer = NULL;
 867         dev->read_buffer_length = 0;
 868         dev->read_packet_length = 0;
 869         spin_lock_init (&dev->read_buffer_lock);
 870         dev->packet_timeout_jiffies = packet_timeout * HZ / 1000;
 871         dev->read_last_arrival = jiffies;
 872
 873         init_waitqueue_head (&dev->read_wait);
 874         init_waitqueue_head (&dev->write_wait);
 875
 876         dev->interrupt_in_buffer = NULL;
 877         dev->interrupt_in_endpoint = NULL;
 878         dev->interrupt_in_urb = NULL;
 879         dev->interrupt_in_running = 0;
 880         dev->interrupt_in_done = 0;
 881
 882         dev->interrupt_out_buffer = NULL;
 883         dev->interrupt_out_endpoint = NULL;
 884         dev->interrupt_out_urb = NULL;
 885         dev->interrupt_out_busy = 0;
 886
 887         iface_desc = interface->cur_altsetting;
 888
 889         /* set up the endpoint information */
 890         for (i = 0; i < iface_desc->desc.bNumEndpoints; ++i) {
 891                 endpoint = &iface_desc->endpoint[i].desc;
 892
 893                 if (usb_endpoint_xfer_int(endpoint)) {
 894                         if (usb_endpoint_dir_in(endpoint))
 895                                 dev->interrupt_in_endpoint = endpoint;
 896                         else
 897                                 dev->interrupt_out_endpoint = endpoint;
 898                 }
 899         }
 900         if(dev->interrupt_in_endpoint == NULL) {
 901                 err("interrupt in endpoint not found");
 902                 goto error;
 903         }
 904         if (dev->interrupt_out_endpoint == NULL) {
 905                 err("interrupt out endpoint not found");
 906                 goto error;
 907         }
 908
 909         dev->read_buffer = kmalloc (read_buffer_size, GFP_KERNEL);
 910         if (!dev->read_buffer) {
 911                 err("Couldn't allocate read_buffer");
 912                 goto error;
 913         }
 914         dev->interrupt_in_buffer = kmalloc (le16_to_cpu(dev->interrupt_in_endpoint->wMaxPacketSize), GFP_KERNEL);
 915         if (!dev->interrupt_in_buffer) {
 916                 err("Couldn't allocate interrupt_in_buffer");
 917                 goto error;
 918         }
 919         dev->interrupt_in_urb = usb_alloc_urb(0, GFP_KERNEL);
 920         if (!dev->interrupt_in_urb) {
 921                 err("Couldn't allocate interrupt_in_urb");
 922                 goto error;
 923         }
 924         dev->interrupt_out_buffer = kmalloc (write_buffer_size, GFP_KERNEL);
 925         if (!dev->interrupt_out_buffer) {
 926                 err("Couldn't allocate interrupt_out_buffer");
 927                 goto error;
 928         }
 929         dev->interrupt_out_urb = usb_alloc_urb(0, GFP_KERNEL);
 930         if (!dev->interrupt_out_urb) {
 931                 err("Couldn't allocate interrupt_out_urb");
 932                 goto error;
 933         }
 934         dev->interrupt_in_interval = interrupt_in_interval ? interrupt_in_interval : dev->interrupt_in_endpoint->bInterval;
 935         dev->interrupt_out_interval = interrupt_out_interval ? interrupt_out_interval : dev->interrupt_out_endpoint->bInterval;
 936
 937         /* we can register the device now, as it is ready */
 938         usb_set_intfdata (interface, dev);
 939
 940         retval = usb_register_dev (interface, &tower_class);
 941
 942         if (retval) {
 943                 /* something prevented us from registering this driver */
 944                 err ("Not able to get a minor for this device.");
 945                 usb_set_intfdata (interface, NULL);
 946                 goto error;
 947         }
 948         dev->minor = interface->minor;
 949
 950         /* let the user know what node this device is now attached to */
 951         info ("LEGO USB Tower #%d now attached to major %d minor %d", (dev->minor - LEGO_USB_TOWER_MINOR_BASE), USB_MAJOR, dev->minor);
 952
 953         /* get the firmware version and log it */
 954         result = usb_control_msg (udev,
 955                                   usb_rcvctrlpipe(udev, 0),
 956                                   LEGO_USB_TOWER_REQUEST_GET_VERSION,
 957                                   USB_TYPE_VENDOR | USB_DIR_IN | USB_RECIP_DEVICE,
 958                                   0,
 959                                   0,
 960                                   &get_version_reply,
 961                                   sizeof(get_version_reply),
 962                                   1000);
 963         if (result < 0) {
 964                 err("LEGO USB Tower get version control request failed");
 965                 retval = result;
 966                 goto error;
 967         }
 968         info("LEGO USB Tower firmware version is %d.%d build %d",
 969              get_version_reply.major,
 970              get_version_reply.minor,
 971              le16_to_cpu(get_version_reply.build_no));
 972
 973
 974 exit:
 975         dbg(2, "%s: leave, return value 0x%.8lx (dev)", __FUNCTION__, (long) dev);
 976
 977         return retval;
 978
 979 error:
 980         tower_delete(dev);
 981         return retval;
 982 }
 983
 984
 985 /**
 986  *      tower_disconnect
 987  *
 988  *      Called by the usb core when the device is removed from the system.
 989  */
 990 static void tower_disconnect (struct usb_interface *interface)
 991 {
 992         struct lego_usb_tower *dev;
 993         int minor;
 994
 995         dbg(2, "%s: enter", __FUNCTION__);
 996
 997         mutex_lock (&disconnect_mutex);
 998
 999         dev = usb_get_intfdata (interface);
1000         usb_set_intfdata (interface, NULL);
1001
1002
1003         down (&dev->sem);
1004
1005         minor = dev->minor;
1006
1007         /* give back our minor */
1008         usb_deregister_dev (interface, &tower_class);
1009
1010         /* if the device is not opened, then we clean up right now */
1011         if (!dev->open_count) {
1012                 up (&dev->sem);
1013                 tower_delete (dev);
1014         } else {
1015                 dev->udev = NULL;
1016                 up (&dev->sem);
1017         }
1018
1019         mutex_unlock (&disconnect_mutex);
1020
1021         info("LEGO USB Tower #%d now disconnected", (minor - LEGO_USB_TOWER_MINOR_BASE));
1022
1023         dbg(2, "%s: leave", __FUNCTION__);
1024 }
1025
1026
1027
1028 /**
1029  *      lego_usb_tower_init
1030  */
1031 static int __init lego_usb_tower_init(void)
1032 {
1033         int result;
1034         int retval = 0;
1035
1036         dbg(2, "%s: enter", __FUNCTION__);
1037
1038         /* register this driver with the USB subsystem */
1039         result = usb_register(&tower_driver);
1040         if (result < 0) {
1041                 err("usb_register failed for the "__FILE__" driver. Error number %d", result);
1042                 retval = -1;
1043                 goto exit;
1044         }
1045
1046         info(DRIVER_DESC " " DRIVER_VERSION);
1047
1048 exit:
1049         dbg(2, "%s: leave, return value %d", __FUNCTION__, retval);
1050
1051         return retval;
1052 }
1053
1054
1055 /**
1056  *      lego_usb_tower_exit
1057  */
1058 static void __exit lego_usb_tower_exit(void)
1059 {
1060         dbg(2, "%s: enter", __FUNCTION__);
1061
1062         /* deregister this driver with the USB subsystem */
1063         usb_deregister (&tower_driver);
1064
1065         dbg(2, "%s: leave", __FUNCTION__);
1066 }
1067
1068 module_init (lego_usb_tower_init);
1069 module_exit (lego_usb_tower_exit);
1070
1071 MODULE_AUTHOR(DRIVER_AUTHOR);
1072 MODULE_DESCRIPTION(DRIVER_DESC);
1073 #ifdef MODULE_LICENSE
1074 MODULE_LICENSE("GPL");
1075 #endif